The aim of this study was to prepare and to characterize the structure of Al2O3–3YSZ composites with 5% TiO2 addition
as well as the surface modification upon treatments with SnF2 and NaBF4, respectively. SEM micrographs showed the
controlled densification of the composites as an effect of 3YSZ and TiO2 addition to alumina matrix. By FTIR and XRD,
the characteristics of Al-O and Zr-O vibrations, respectively, the diffractions lines related to a-corundum and zirconia in
tetragonal phase were discussed. Qualitative and quantitative results obtained by XPS and ATR FTIR demonstrated that the
proposed materials are more sensitive to SnF2 than to NaBF4 treatment.
Dry Sliding Wear Behaviour of Rheocat Al-5.7Si-2Cu-0.3Mg AlloyDr. Manal Abdullatif
In this study, the effect of improved microstructure of Al-5.7Si-2Cu-0.3Mg alloys by using semisolid process on hardness and dry sliding wear behaviour were investigated. The microstructures of conventional cast alloy were totally dendritic, while in rheocasting the dendrit-ic transfer to fine globular microstructures after using cooling slope casting. Tribological tests were carried out by using a pin-on-disc apparatus in dry sliding conditions. Wear tests were at low sliding speed 1ms-1 ,applied load at 50N and three different sliding distance (i.e., 1.8Km, 5.4Km and 9Km) respectively. An optical microscope and a scanning electron microscope were used to examine the micro-structure and to understand the wear mechanism on the worn surface of both samples. The results showed that, the wear resistance of rheocast alloy was improved and higher than that those produce by conventional casting. The volume loss of rheocast alloy show reduc-tion more than 18% at 1.8Km and 10% at 9Km compared to as-cast alloy. Moderate wear regimes were appeared in both alloys, accord-ing to the range of wear rate. The friction coefficient had increased due to increase in the contact point between pin and disc materials. The dominant wear mechanism for conventional and rheocasting alloys was adhesion wear and abrasive wear respectively.
Investigate Temperature Preheating on the Chill Plate to Identify Surface Cha...Natalino Fonseca
1. The document describes an investigation into the effect of temperature preheating on the chill plate to characterize the surface of ductile iron castings.
2. Samples of ductile iron were cast against chill plates that were preheated to different temperatures (500°C, 700°C, 900°C, and unheated) to study the microhardness, surface layer thickness, and elemental composition on the casting surface.
3. Preliminary results found that higher preheat temperatures produced a carbide structure on the casting surface, while no preheating resulted in a fully ferritic microstructure with uniform carbide formation and a pearlite-ferrite microstructure.
. One of the methods used to surface hardening of ductile iron is chilled cast iron. Chill as the fast cooling rate in the mold during solidification and chill thickness greatly affects the thickness of the hardness layer. The main material used is ductile iron, and the chill material is SS 304. Casting uses the sand casting method. Before pouring, the chill plate has been inserted onto the surface of the pattern that has been formed in the mold, then the chill plate is preheated at 700OC. Pouring was carried out at a melting temperature of 1400OC, and then cooled with argon and O2 sprays into the mold in solidification conditions at exactly 700OC. The results analyzed were the microstructure, hardness value, and the hardness of the thickness layer. This chill coolant will absorb heat very quickly and the Cr and Ni alloy will diffuse to the specimen surface to stabilize the ferrite and austenite phases in the final solidification. The particles on the hard surface have Ferro carbide M7C3, which is in the form of cementite and martensitic phases so that to categorized as white cast iron structure formed on the surface with an area around 1.5-3mm has a hardness of 61-65HRC. But in the center area is 31-49HRC
The Influence of Shot Angle Variation at the Process of Dry Shot Peening to t...IJAEMSJORNAL
AISI 316L is the austenitic stainless steel type that widely used in biomedical implant and artificial organs. This material’s cannot be hardened by heat treatment but the mechanical strength could be increased by cold working process. Dry shot peening is the one of cold working process in which the surface specimen bombarded with spherical media called shot to produce a compressive residual stress layer and modify mechanical properties of metal’s surface. The objectives of this research are to investigate the effect of shot angle variation of dry shot peening process on the surface roughness and corrosion resistance of AISI 316L.
Effect of Nanoporous Anodic Aluminum Oxide (AAO) Characteristics On Solar Abs...A Behzadmehr
Nanoporous anodic aluminum oxide (AAO) has been used in many different fields of science and technology, due to its great structural characteristics. Solar selective surface is an important application of this type porous material. This paper investigates the effect of nanoporous AAO properties, including; film thickness, pore area percentage and pore diameter, on absorption spectra in the range of solar radiation. The parameters were verified individually depending on anodization condition, and the absorption spectra were characterized using spectrophotometer analysis. The results showed that the absorptivity was increased with growth of the film thickness. Furthermore, increasing the pore diameter shifted the absorption spectra to the right range, and vice versa. The investigation revealed the presence of an optimum pore area percentage around 14% in which the absorptivity was at its maximum value.
This document summarizes research on modifying the surface of titanium alloys through radio frequency magnetron sputtering of titanium dioxide (TiO2) thin films at different thicknesses. TiO2 films with thicknesses of 200, 300, and 500nm were deposited on commercially pure titanium (CPTi) and Ti-6Al-4V alloy substrates heated to 100°C using argon gas under low pressure. Field emission scanning electron microscopy, optical microscopy, and Vickers microhardness tests were performed to analyze surface morphology, microstructure, and hardness at each film thickness. Preliminary results indicate hardness increases and corrosion resistance improves for coated samples compared to uncoated, especially for the 300nm film thickness.
Erosive Corrosive Wear Performance of Single Layer CrN Coatings on AISI 304 S...IJAEMSJORNAL
The purpose of present study was to investigate the erosive corrosive wear behavior of single layer (CrN) coatings on AISI 304 Stainless Steel samples with varying coating thickness (0-200 nm) in the range of 50 nm. The slurry jet erosive test was conducted on Slurry Jet Erosion Tester in saline slurry (3.5wt% salt) under the different working conditions with varying impact velocity (10-25 m/s), impingement angle (30°-75°) and erodent discharge (160-280 gm/min). Steady state analysis was applied to find optimum parameters for the minimization of erosion rate of various coated and uncoated samples. The finding of steady state condition tests indicated that the erosion rate increased with the increase in impact velocity and erodent discharge but decreased with the increase in coating thickness. The results also indicated that erodent discharge was the most significant factor, followed by impingement angle and impact velocity for the CrN coated samples. The SEM characterization of the eroded samples was carried out in order to analyze the topography of the eroded surface to investigate the wear mechanisms induced by slurry jet erosion test.
This document summarizes a study on the effects of yttrium on the mechanical properties and chemical stability of the passive film on an aluminide coating applied to 1045 steel. Samples were prepared with and without the addition of yttrium. Nanoindentation tests found that the yttrium-containing coating had greater hardness and elasticity than the yttrium-free coating. Scratch tests also showed that the passive film on the yttrium coating had a higher critical load, indicating greater resistance to failure. Electron work function measurements demonstrated that the passive film on the yttrium coating was more chemically stable. The addition of yttrium improved both the mechanical properties and chemical stability of the passive film, enhancing corrosion and
Dry Sliding Wear Behaviour of Rheocat Al-5.7Si-2Cu-0.3Mg AlloyDr. Manal Abdullatif
In this study, the effect of improved microstructure of Al-5.7Si-2Cu-0.3Mg alloys by using semisolid process on hardness and dry sliding wear behaviour were investigated. The microstructures of conventional cast alloy were totally dendritic, while in rheocasting the dendrit-ic transfer to fine globular microstructures after using cooling slope casting. Tribological tests were carried out by using a pin-on-disc apparatus in dry sliding conditions. Wear tests were at low sliding speed 1ms-1 ,applied load at 50N and three different sliding distance (i.e., 1.8Km, 5.4Km and 9Km) respectively. An optical microscope and a scanning electron microscope were used to examine the micro-structure and to understand the wear mechanism on the worn surface of both samples. The results showed that, the wear resistance of rheocast alloy was improved and higher than that those produce by conventional casting. The volume loss of rheocast alloy show reduc-tion more than 18% at 1.8Km and 10% at 9Km compared to as-cast alloy. Moderate wear regimes were appeared in both alloys, accord-ing to the range of wear rate. The friction coefficient had increased due to increase in the contact point between pin and disc materials. The dominant wear mechanism for conventional and rheocasting alloys was adhesion wear and abrasive wear respectively.
Investigate Temperature Preheating on the Chill Plate to Identify Surface Cha...Natalino Fonseca
1. The document describes an investigation into the effect of temperature preheating on the chill plate to characterize the surface of ductile iron castings.
2. Samples of ductile iron were cast against chill plates that were preheated to different temperatures (500°C, 700°C, 900°C, and unheated) to study the microhardness, surface layer thickness, and elemental composition on the casting surface.
3. Preliminary results found that higher preheat temperatures produced a carbide structure on the casting surface, while no preheating resulted in a fully ferritic microstructure with uniform carbide formation and a pearlite-ferrite microstructure.
. One of the methods used to surface hardening of ductile iron is chilled cast iron. Chill as the fast cooling rate in the mold during solidification and chill thickness greatly affects the thickness of the hardness layer. The main material used is ductile iron, and the chill material is SS 304. Casting uses the sand casting method. Before pouring, the chill plate has been inserted onto the surface of the pattern that has been formed in the mold, then the chill plate is preheated at 700OC. Pouring was carried out at a melting temperature of 1400OC, and then cooled with argon and O2 sprays into the mold in solidification conditions at exactly 700OC. The results analyzed were the microstructure, hardness value, and the hardness of the thickness layer. This chill coolant will absorb heat very quickly and the Cr and Ni alloy will diffuse to the specimen surface to stabilize the ferrite and austenite phases in the final solidification. The particles on the hard surface have Ferro carbide M7C3, which is in the form of cementite and martensitic phases so that to categorized as white cast iron structure formed on the surface with an area around 1.5-3mm has a hardness of 61-65HRC. But in the center area is 31-49HRC
The Influence of Shot Angle Variation at the Process of Dry Shot Peening to t...IJAEMSJORNAL
AISI 316L is the austenitic stainless steel type that widely used in biomedical implant and artificial organs. This material’s cannot be hardened by heat treatment but the mechanical strength could be increased by cold working process. Dry shot peening is the one of cold working process in which the surface specimen bombarded with spherical media called shot to produce a compressive residual stress layer and modify mechanical properties of metal’s surface. The objectives of this research are to investigate the effect of shot angle variation of dry shot peening process on the surface roughness and corrosion resistance of AISI 316L.
Effect of Nanoporous Anodic Aluminum Oxide (AAO) Characteristics On Solar Abs...A Behzadmehr
Nanoporous anodic aluminum oxide (AAO) has been used in many different fields of science and technology, due to its great structural characteristics. Solar selective surface is an important application of this type porous material. This paper investigates the effect of nanoporous AAO properties, including; film thickness, pore area percentage and pore diameter, on absorption spectra in the range of solar radiation. The parameters were verified individually depending on anodization condition, and the absorption spectra were characterized using spectrophotometer analysis. The results showed that the absorptivity was increased with growth of the film thickness. Furthermore, increasing the pore diameter shifted the absorption spectra to the right range, and vice versa. The investigation revealed the presence of an optimum pore area percentage around 14% in which the absorptivity was at its maximum value.
This document summarizes research on modifying the surface of titanium alloys through radio frequency magnetron sputtering of titanium dioxide (TiO2) thin films at different thicknesses. TiO2 films with thicknesses of 200, 300, and 500nm were deposited on commercially pure titanium (CPTi) and Ti-6Al-4V alloy substrates heated to 100°C using argon gas under low pressure. Field emission scanning electron microscopy, optical microscopy, and Vickers microhardness tests were performed to analyze surface morphology, microstructure, and hardness at each film thickness. Preliminary results indicate hardness increases and corrosion resistance improves for coated samples compared to uncoated, especially for the 300nm film thickness.
Erosive Corrosive Wear Performance of Single Layer CrN Coatings on AISI 304 S...IJAEMSJORNAL
The purpose of present study was to investigate the erosive corrosive wear behavior of single layer (CrN) coatings on AISI 304 Stainless Steel samples with varying coating thickness (0-200 nm) in the range of 50 nm. The slurry jet erosive test was conducted on Slurry Jet Erosion Tester in saline slurry (3.5wt% salt) under the different working conditions with varying impact velocity (10-25 m/s), impingement angle (30°-75°) and erodent discharge (160-280 gm/min). Steady state analysis was applied to find optimum parameters for the minimization of erosion rate of various coated and uncoated samples. The finding of steady state condition tests indicated that the erosion rate increased with the increase in impact velocity and erodent discharge but decreased with the increase in coating thickness. The results also indicated that erodent discharge was the most significant factor, followed by impingement angle and impact velocity for the CrN coated samples. The SEM characterization of the eroded samples was carried out in order to analyze the topography of the eroded surface to investigate the wear mechanisms induced by slurry jet erosion test.
This document summarizes a study on the effects of yttrium on the mechanical properties and chemical stability of the passive film on an aluminide coating applied to 1045 steel. Samples were prepared with and without the addition of yttrium. Nanoindentation tests found that the yttrium-containing coating had greater hardness and elasticity than the yttrium-free coating. Scratch tests also showed that the passive film on the yttrium coating had a higher critical load, indicating greater resistance to failure. Electron work function measurements demonstrated that the passive film on the yttrium coating was more chemically stable. The addition of yttrium improved both the mechanical properties and chemical stability of the passive film, enhancing corrosion and
The document describes an experimental study of the tribological properties of commercially pure titanium with different microstructures and coatings. The results show that titanium with an ultrafine-grained structure produced through severe plastic deformation has lower friction coefficient values and higher load-bearing capacity compared to coarse-grained titanium. Titanium samples coated with TiC using ion plasma spraying or TiO2 using microarc oxidation also exhibited lower friction coefficients than uncoated samples. The study provides data on friction coefficients and shear strengths of coated and uncoated titanium with different grain sizes.
Detecting of NH3, CO2 polluted gases by using ZnO- In2O3 thin filmsijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
This document summarizes a study on eliminating white layer formation during hard turning of AISI D3 steel to improve fatigue life. Experiments were conducted using chamfered CBN tool inserts under dry and gas cooling conditions. Results found that gas cooling with argon and CO2 eliminated the white layer, which was over 2 μm thick with dry cutting. Surface hardness was also lower with gas cooling than dry cutting. Microstructural analysis found depletion of iron and chromium and increase in carbon and oxygen in the white layer formed during dry cutting. Gas cooling protected the machined surface and reduced phase transformations. In conclusion, using argon and CO2 gas cooling can eliminate white layer formation during hard turning of hardened steel.
Corrosion Measursement, Friction testing and XRD Analysis of Single Layer CrN...IJAEMSJORNAL
The purpose of present study was to investigate the erosive corrosive wear behavior of single layer (CrN) coatings on AISI 304 Stainless Steel samples with varying coating thickness (0-200 nm) in the range of 50 nm. The slurry jet erosive test was conducted on Slurry Jet Erosion Tester in saline slurry (3.5wt% salt) under the different working conditions with varying impact velocity (10-25 m/s), impingement angle (30°-75°) and erodent discharge (160-280 gm/min). Corrosion tests were conducted in 3.5 wt. % NaCl solution using a Potentiostat, in order to analyze the corrosion behavior of the coated samples in sea water environment. Coefficient of friction was measured using a Scratch Tester. XRD analysis of the eroded samples indicated the presence of both CrN and Cr2N (200) in the coatings.
The document summarizes a study characterizing the anodized film developed on titanium plates in a KOH bath. Key findings:
1. Anodizing titanium in a KOH bath between 20-72V produced films with colors ranging from blue to yellow to purple to green.
2. Analysis found the film consisted mainly of TiO2 and Ti2O3 and was uniform and compact.
3. Corrosion testing showed the film anodized at 50-52V exhibited the best corrosion resistance in salt spray, acid, and impedance tests, while films at lower and higher voltages had decreasing resistance.
Sebastiani - Nano-mechanical and microstructural characterization of MS-PVD N...thinfilmsworkshop
This document summarizes a presentation on nano-mechanical and microstructural characterization of niobium thin films deposited by magnetron sputtering. Key points discussed include:
- Four niobium coatings were produced by varying the applied bias voltage and substrate material.
- Nanoindentation testing revealed the coatings' hardness is not affected by the substrate at depths less than one tenth the coating thickness.
- Analysis of deformation mechanisms using FIB sectioning showed columnar grain sliding and recrystallization during plastic deformation.
- A thin surface oxide layer of around 10nm was found, which could impact the coatings' superconducting performance.
This study examined the aluminizing behavior of low carbon steel with and without surface mechanical attrition treatment (SMAT) at lower temperatures. The following were observed for the SMAT sample compared to the untreated sample:
1) A much thicker iron aluminide compound layer formed with an enhanced growth kinetics of the η-Fe2Al5 phase at temperatures as low as 500-600°C.
2) The aluminide layer in the SMAT sample had a weakened crystallographic texture compared to the untreated sample.
3) The promoted aluminizing kinetics in the SMAT sample is attributed to increased diffusion and nucleation frequency in the nanostructured surface layer produced by SMAT.
Direct coupling of a carbon nanotube membrane to a mass spectrometer - contra...David Edwards
This document summarizes a study comparing a carbon nanotube membrane to a capillary tube for introducing gas samples to a mass spectrometer. Carbon nanotubes were grown within the pores of an aluminum oxide membrane using chemical vapor deposition. The selectivity and conductance properties of gases passing through the carbon nanotube membrane versus a capillary tube were then evaluated using the mass spectrometer. The study found the carbon nanotube membrane was more transmissive to methane than the capillary tube. Conductance through the two systems also differed in their dependence on total pressure for various gases.
This document provides an overview of various nanotechnology applications including DNA sequencing using nanopores, filtration, uses in clothing and sports, composites, nanomedicine, superconductors, magnetic nanowires, ferroelectrics, and dielectric nanostructures. It also discusses the business of nanotechnology and provides examples of research on growing superconducting lead nanowires, fabricating yttrium barium copper oxide superconductor nanowires, investigating the magnetic properties of ferromagnetic nanowires, and developing ferroelectric nanotubes and metamaterials using dielectric nanostructures.
The document summarizes a study on increasing the salt fog corrosion resistance of plasma nitrided AISI 4340 steel through a pulsed plasma post-oxidation process. Key findings:
1) Post-oxidation treatment produces an oxidized layer on the nitrided surface that fills and seals pores, improving corrosion resistance.
2) Samples post-oxidized for 15 minutes showed the best corrosion performance when exposed to salt fog, with only 1/16 as much red rust as nitrided samples alone.
3) X-ray diffraction analysis found the oxidized layer consisted mainly of magnetite iron oxide, which provides high corrosion resistance.
Taguchi analysis of single layer CrN coatings on AISI 304 Stainless Steel to ...IJAEMSJORNAL
This document summarizes a study investigating the erosive corrosive wear behavior of single layer chromium nitride (CrN) coatings on AISI 304 stainless steel samples. Taguchi analysis was used to test coated and uncoated samples under varying impact velocity, impingement angle, and erodent discharge. The results showed that CrN coatings reduced the wear rate by nearly 2 times compared to uncoated samples. Taguchi analysis identified that among coated samples, erodent discharge was the most significant factor affecting wear rate, followed by coating thickness and impingement angle, with impact velocity being the least significant. For uncoated samples, impact velocity was the most significant factor. The optimum parameters for minimum wear rate
Effect of broaching on high temperature fatigue behaviorPhuong Dx
The document discusses the effect of broaching on the high-temperature fatigue behavior of notched INCONEL 718 specimens. Two batches of specimens were broached, resulting in differing extents of subsurface deformation and surface roughness. Fatigue tests at 600°C found that the batch with more severe subsurface deformation, but lower surface roughness, had the worst fatigue performance. Finite element analysis showed the work hardening from subsurface deformation accounted for the difference in fatigue lives between batches. Differences were also seen in crack initiation and growth behavior between batches and between broached and polished specimens.
EROSION PROTECTION OF PULVERIZED BOILER COAL PREPARATION EQUIPMENTMilos Djukic
This document summarizes research on erosion protection materials for pulverized coal preparation equipment in fossil fuel power plants. Samples were tested with different erosion protection materials applied, including two metal alloy coatings applied via cold spraying and one alloy applied via weld overlay. Following erosion testing, the samples were analyzed to compare erosion damage profiles and weight loss. Microstructural analysis found that the weld overlay sample showed the best erosion resistance for the given test conditions, with the cold spray coatings also demonstrating good bonding quality to the substrate. Further testing is needed to determine the best erosion protection methods for different equipment and operating conditions.
INVESTIGATION OF OXIDATION RESISTANCE OF NI- TI ELECTROCHEMICAL CODEPOSITION ...IAEME Publication
The effects of Ti particle loading in a plating bath on the morphology and hardness of Ni-Ti composite coatings via an electrochemical codeposition coating were investigated. The Ti-reinforced Ni-matrix composite coatings were codeposited on Austenitic Stainless Steel (316 L) substrates using a Ni-ion electrolytic solution stably suspended with -20 m max. diameter Ti particles and heat treated under vacuum atmosphere for six hours at 950 °C prior to oxidation testing.
IRJET - Tribological Characteristics of Al-SIC-MOS2 Cylindrical Powder Prefor...IRJET Journal
The document summarizes the tribological characteristics of Al-SiC-MoS2 cylindrical powder preforms under dry atmospheric conditions. It discusses conducting wear tests using a pin-on-disc apparatus against silicon carbide abrasive paper under various testing conditions such as applied load, sliding velocity, and time. The wear is measured by weight loss and the relationship between weight loss and applied load is established. Materials used include aluminum, silicon carbide, and molybdenum disulfide powder preforms compacted at different pressures and sintered at one temperature.
Densification and deformation behaviour of sinteredIAEME Publication
This document summarizes a study on the densification and deformation behavior of sintered powder metallurgy copper-7% tungsten composite during cold upsetting. The study evaluated the effect of initial preform density and aspect ratio on the densification properties. Preforms with an initial theoretical density of 0.85 and aspect ratios of 0.4, 0.6, and 0.8 were upset at 750°C. Properties like linear strain, lateral strain, and true stress were evaluated. Results showed that composites obtained higher stress and strain values than pure tungsten powder. The composite with the lowest initial aspect ratio of 0.4 achieved the highest stress and strain.
Corrosion Behaviour of Titanium Anodized Film in Different Corrosive Environm...IJERA Editor
Anodizing is an electrochemical process in which thickness of the natural oxide layer is increased and converted it into a decorative, durable, corrosion-resistant film. Titanium is used as a biocompatible material in human implants due to its excellent corrosion and wears resistance. Stable, continuous, highly adherent, and protective oxide films can be developed on titanium using various acid or alkaline baths. Anodizing of titanium generates a spectrum of different color without use of dyes. This spectrum of color dependent on the thickness of the oxide, voltage ranges, interference of light reflecting off the oxide surface and reflecting off the underlying metal surface. The anodized film of Titanium is mainly consists of TiO2 or mixtures of TiO2 & Ti2O3 etc. In the present work, Pure Titanium plate has been anodized using bath of Chromic Acid at different voltage range. The anodized film is characterized by visual observation, SEM & EDAX analysis & A.C Impedance Spectroscopy, while the corrosion studies were performed using Potentiodynamic studies were performed in 3.5% NaCl & 0.1N H2SO4. The Results show that the anodized film of Titanium show different spectrum of colors from Brown-Violet-Tea or Peacock. SEM & EDAX analyses show that the anodized film of Titanium is mainly made up of TiO2 and Ti2O3. Potentiodynamic study implies that the film developed on Titanium using the bath of Chromic Acid exhibits good corrosion resistance. The A.C. Impedance study shows that the film is more compact, adherent and more uniform in chromic acid bath.
Simona cavalu_ Adherence Properties of Acrylic Bone Cement to AluminaSimona Cavalu
The aim of this study is to investigate the adherence properties of acrylic cement based on PMMA to alumina
ceramics. These ceramics are suitable for orthopedic and dental applications, as bioinert components in prosthetic
surgery. The surface of alumina specimens were subjected to a special treatment based on acid etched followed by
two dierent uoride treatments: SnF2 and NaBF4, respectively.
Annealing and Microstructural Characterization of Tin-Oxide Based Thick Film ...Anis Rahman
Abstract. The sheet resistance of tin oxide based thick-film resistors exhibits two regions of temperature dependence,
described by hopping (23°C-200°C) and diffusion mechanisms (200°C-350°C), respectively.
Annealing these samples causes the sheet resistance to increase in both regions. In the post-annealed samples,
the hopping conduction range is extended by 50°C (23°C-250°C) while the hopping parameter, To, is decreased by
more than 50%. The activation energy of diffusion (0.60 eV) is the same for both pre- and post annealed samples, but
the magnitude of resistance in the diffusion controlled region is increased significantly as a result of annealing. These
changes are explained in terms of a net decrease in the concentration of tin ions in the glass matrix. From a careful
microstructural study it was found that a conduction path composed of tin-oxide grains or their clusters in contact
with each other does not exist in the present system. HREM micrographs showed the presence of nanocrystalline
tin-oxide particles in the glass phase separating the tin-oxide grain clusters. Estimated average separation between
the nanocrystals in 4 nm, consistent with a variable-range hopping conduction via the dissolved tin ions in the glass
matrix.
surface characteristics and electrochemical impedance investigation of spark-...mohammad fazel
This document summarizes a study that investigated the surface characteristics of oxide films formed on Ti-6Al-4V alloy by spark anodization in H2SO4/H3PO4 electrolyte at different voltages. The results showed that increasing the anodization voltage increased the pore diameter and porosity of the oxide layer. Higher voltages also produced thicker oxide layers and rougher surfaces. Analysis found the layers incorporated elements from the electrolyte and consisted of crystalline anatase. Electrochemical testing indicated the impedance behavior was affected by the space charge region, inner compact layer and outer porous layer, and that corrosion resistance decreased with higher voltages.
Stainless steels are selected primarily for their excellent corrosion and oxidation resistance properties. One of the effective methods for manufacturing stainless steel parts of high quality and accuracy at low cost is through powder metallurgy. The demand for sintered stainless steels has
increased notably, in the recent years due to their promising properties, ease of fabrication, and are economical in production, especially where number of complex objects are involved.
The document describes an experimental study of the tribological properties of commercially pure titanium with different microstructures and coatings. The results show that titanium with an ultrafine-grained structure produced through severe plastic deformation has lower friction coefficient values and higher load-bearing capacity compared to coarse-grained titanium. Titanium samples coated with TiC using ion plasma spraying or TiO2 using microarc oxidation also exhibited lower friction coefficients than uncoated samples. The study provides data on friction coefficients and shear strengths of coated and uncoated titanium with different grain sizes.
Detecting of NH3, CO2 polluted gases by using ZnO- In2O3 thin filmsijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
This document summarizes a study on eliminating white layer formation during hard turning of AISI D3 steel to improve fatigue life. Experiments were conducted using chamfered CBN tool inserts under dry and gas cooling conditions. Results found that gas cooling with argon and CO2 eliminated the white layer, which was over 2 μm thick with dry cutting. Surface hardness was also lower with gas cooling than dry cutting. Microstructural analysis found depletion of iron and chromium and increase in carbon and oxygen in the white layer formed during dry cutting. Gas cooling protected the machined surface and reduced phase transformations. In conclusion, using argon and CO2 gas cooling can eliminate white layer formation during hard turning of hardened steel.
Corrosion Measursement, Friction testing and XRD Analysis of Single Layer CrN...IJAEMSJORNAL
The purpose of present study was to investigate the erosive corrosive wear behavior of single layer (CrN) coatings on AISI 304 Stainless Steel samples with varying coating thickness (0-200 nm) in the range of 50 nm. The slurry jet erosive test was conducted on Slurry Jet Erosion Tester in saline slurry (3.5wt% salt) under the different working conditions with varying impact velocity (10-25 m/s), impingement angle (30°-75°) and erodent discharge (160-280 gm/min). Corrosion tests were conducted in 3.5 wt. % NaCl solution using a Potentiostat, in order to analyze the corrosion behavior of the coated samples in sea water environment. Coefficient of friction was measured using a Scratch Tester. XRD analysis of the eroded samples indicated the presence of both CrN and Cr2N (200) in the coatings.
The document summarizes a study characterizing the anodized film developed on titanium plates in a KOH bath. Key findings:
1. Anodizing titanium in a KOH bath between 20-72V produced films with colors ranging from blue to yellow to purple to green.
2. Analysis found the film consisted mainly of TiO2 and Ti2O3 and was uniform and compact.
3. Corrosion testing showed the film anodized at 50-52V exhibited the best corrosion resistance in salt spray, acid, and impedance tests, while films at lower and higher voltages had decreasing resistance.
Sebastiani - Nano-mechanical and microstructural characterization of MS-PVD N...thinfilmsworkshop
This document summarizes a presentation on nano-mechanical and microstructural characterization of niobium thin films deposited by magnetron sputtering. Key points discussed include:
- Four niobium coatings were produced by varying the applied bias voltage and substrate material.
- Nanoindentation testing revealed the coatings' hardness is not affected by the substrate at depths less than one tenth the coating thickness.
- Analysis of deformation mechanisms using FIB sectioning showed columnar grain sliding and recrystallization during plastic deformation.
- A thin surface oxide layer of around 10nm was found, which could impact the coatings' superconducting performance.
This study examined the aluminizing behavior of low carbon steel with and without surface mechanical attrition treatment (SMAT) at lower temperatures. The following were observed for the SMAT sample compared to the untreated sample:
1) A much thicker iron aluminide compound layer formed with an enhanced growth kinetics of the η-Fe2Al5 phase at temperatures as low as 500-600°C.
2) The aluminide layer in the SMAT sample had a weakened crystallographic texture compared to the untreated sample.
3) The promoted aluminizing kinetics in the SMAT sample is attributed to increased diffusion and nucleation frequency in the nanostructured surface layer produced by SMAT.
Direct coupling of a carbon nanotube membrane to a mass spectrometer - contra...David Edwards
This document summarizes a study comparing a carbon nanotube membrane to a capillary tube for introducing gas samples to a mass spectrometer. Carbon nanotubes were grown within the pores of an aluminum oxide membrane using chemical vapor deposition. The selectivity and conductance properties of gases passing through the carbon nanotube membrane versus a capillary tube were then evaluated using the mass spectrometer. The study found the carbon nanotube membrane was more transmissive to methane than the capillary tube. Conductance through the two systems also differed in their dependence on total pressure for various gases.
This document provides an overview of various nanotechnology applications including DNA sequencing using nanopores, filtration, uses in clothing and sports, composites, nanomedicine, superconductors, magnetic nanowires, ferroelectrics, and dielectric nanostructures. It also discusses the business of nanotechnology and provides examples of research on growing superconducting lead nanowires, fabricating yttrium barium copper oxide superconductor nanowires, investigating the magnetic properties of ferromagnetic nanowires, and developing ferroelectric nanotubes and metamaterials using dielectric nanostructures.
The document summarizes a study on increasing the salt fog corrosion resistance of plasma nitrided AISI 4340 steel through a pulsed plasma post-oxidation process. Key findings:
1) Post-oxidation treatment produces an oxidized layer on the nitrided surface that fills and seals pores, improving corrosion resistance.
2) Samples post-oxidized for 15 minutes showed the best corrosion performance when exposed to salt fog, with only 1/16 as much red rust as nitrided samples alone.
3) X-ray diffraction analysis found the oxidized layer consisted mainly of magnetite iron oxide, which provides high corrosion resistance.
Taguchi analysis of single layer CrN coatings on AISI 304 Stainless Steel to ...IJAEMSJORNAL
This document summarizes a study investigating the erosive corrosive wear behavior of single layer chromium nitride (CrN) coatings on AISI 304 stainless steel samples. Taguchi analysis was used to test coated and uncoated samples under varying impact velocity, impingement angle, and erodent discharge. The results showed that CrN coatings reduced the wear rate by nearly 2 times compared to uncoated samples. Taguchi analysis identified that among coated samples, erodent discharge was the most significant factor affecting wear rate, followed by coating thickness and impingement angle, with impact velocity being the least significant. For uncoated samples, impact velocity was the most significant factor. The optimum parameters for minimum wear rate
Effect of broaching on high temperature fatigue behaviorPhuong Dx
The document discusses the effect of broaching on the high-temperature fatigue behavior of notched INCONEL 718 specimens. Two batches of specimens were broached, resulting in differing extents of subsurface deformation and surface roughness. Fatigue tests at 600°C found that the batch with more severe subsurface deformation, but lower surface roughness, had the worst fatigue performance. Finite element analysis showed the work hardening from subsurface deformation accounted for the difference in fatigue lives between batches. Differences were also seen in crack initiation and growth behavior between batches and between broached and polished specimens.
EROSION PROTECTION OF PULVERIZED BOILER COAL PREPARATION EQUIPMENTMilos Djukic
This document summarizes research on erosion protection materials for pulverized coal preparation equipment in fossil fuel power plants. Samples were tested with different erosion protection materials applied, including two metal alloy coatings applied via cold spraying and one alloy applied via weld overlay. Following erosion testing, the samples were analyzed to compare erosion damage profiles and weight loss. Microstructural analysis found that the weld overlay sample showed the best erosion resistance for the given test conditions, with the cold spray coatings also demonstrating good bonding quality to the substrate. Further testing is needed to determine the best erosion protection methods for different equipment and operating conditions.
INVESTIGATION OF OXIDATION RESISTANCE OF NI- TI ELECTROCHEMICAL CODEPOSITION ...IAEME Publication
The effects of Ti particle loading in a plating bath on the morphology and hardness of Ni-Ti composite coatings via an electrochemical codeposition coating were investigated. The Ti-reinforced Ni-matrix composite coatings were codeposited on Austenitic Stainless Steel (316 L) substrates using a Ni-ion electrolytic solution stably suspended with -20 m max. diameter Ti particles and heat treated under vacuum atmosphere for six hours at 950 °C prior to oxidation testing.
IRJET - Tribological Characteristics of Al-SIC-MOS2 Cylindrical Powder Prefor...IRJET Journal
The document summarizes the tribological characteristics of Al-SiC-MoS2 cylindrical powder preforms under dry atmospheric conditions. It discusses conducting wear tests using a pin-on-disc apparatus against silicon carbide abrasive paper under various testing conditions such as applied load, sliding velocity, and time. The wear is measured by weight loss and the relationship between weight loss and applied load is established. Materials used include aluminum, silicon carbide, and molybdenum disulfide powder preforms compacted at different pressures and sintered at one temperature.
Densification and deformation behaviour of sinteredIAEME Publication
This document summarizes a study on the densification and deformation behavior of sintered powder metallurgy copper-7% tungsten composite during cold upsetting. The study evaluated the effect of initial preform density and aspect ratio on the densification properties. Preforms with an initial theoretical density of 0.85 and aspect ratios of 0.4, 0.6, and 0.8 were upset at 750°C. Properties like linear strain, lateral strain, and true stress were evaluated. Results showed that composites obtained higher stress and strain values than pure tungsten powder. The composite with the lowest initial aspect ratio of 0.4 achieved the highest stress and strain.
Corrosion Behaviour of Titanium Anodized Film in Different Corrosive Environm...IJERA Editor
Anodizing is an electrochemical process in which thickness of the natural oxide layer is increased and converted it into a decorative, durable, corrosion-resistant film. Titanium is used as a biocompatible material in human implants due to its excellent corrosion and wears resistance. Stable, continuous, highly adherent, and protective oxide films can be developed on titanium using various acid or alkaline baths. Anodizing of titanium generates a spectrum of different color without use of dyes. This spectrum of color dependent on the thickness of the oxide, voltage ranges, interference of light reflecting off the oxide surface and reflecting off the underlying metal surface. The anodized film of Titanium is mainly consists of TiO2 or mixtures of TiO2 & Ti2O3 etc. In the present work, Pure Titanium plate has been anodized using bath of Chromic Acid at different voltage range. The anodized film is characterized by visual observation, SEM & EDAX analysis & A.C Impedance Spectroscopy, while the corrosion studies were performed using Potentiodynamic studies were performed in 3.5% NaCl & 0.1N H2SO4. The Results show that the anodized film of Titanium show different spectrum of colors from Brown-Violet-Tea or Peacock. SEM & EDAX analyses show that the anodized film of Titanium is mainly made up of TiO2 and Ti2O3. Potentiodynamic study implies that the film developed on Titanium using the bath of Chromic Acid exhibits good corrosion resistance. The A.C. Impedance study shows that the film is more compact, adherent and more uniform in chromic acid bath.
Simona cavalu_ Adherence Properties of Acrylic Bone Cement to AluminaSimona Cavalu
The aim of this study is to investigate the adherence properties of acrylic cement based on PMMA to alumina
ceramics. These ceramics are suitable for orthopedic and dental applications, as bioinert components in prosthetic
surgery. The surface of alumina specimens were subjected to a special treatment based on acid etched followed by
two dierent uoride treatments: SnF2 and NaBF4, respectively.
Annealing and Microstructural Characterization of Tin-Oxide Based Thick Film ...Anis Rahman
Abstract. The sheet resistance of tin oxide based thick-film resistors exhibits two regions of temperature dependence,
described by hopping (23°C-200°C) and diffusion mechanisms (200°C-350°C), respectively.
Annealing these samples causes the sheet resistance to increase in both regions. In the post-annealed samples,
the hopping conduction range is extended by 50°C (23°C-250°C) while the hopping parameter, To, is decreased by
more than 50%. The activation energy of diffusion (0.60 eV) is the same for both pre- and post annealed samples, but
the magnitude of resistance in the diffusion controlled region is increased significantly as a result of annealing. These
changes are explained in terms of a net decrease in the concentration of tin ions in the glass matrix. From a careful
microstructural study it was found that a conduction path composed of tin-oxide grains or their clusters in contact
with each other does not exist in the present system. HREM micrographs showed the presence of nanocrystalline
tin-oxide particles in the glass phase separating the tin-oxide grain clusters. Estimated average separation between
the nanocrystals in 4 nm, consistent with a variable-range hopping conduction via the dissolved tin ions in the glass
matrix.
surface characteristics and electrochemical impedance investigation of spark-...mohammad fazel
This document summarizes a study that investigated the surface characteristics of oxide films formed on Ti-6Al-4V alloy by spark anodization in H2SO4/H3PO4 electrolyte at different voltages. The results showed that increasing the anodization voltage increased the pore diameter and porosity of the oxide layer. Higher voltages also produced thicker oxide layers and rougher surfaces. Analysis found the layers incorporated elements from the electrolyte and consisted of crystalline anatase. Electrochemical testing indicated the impedance behavior was affected by the space charge region, inner compact layer and outer porous layer, and that corrosion resistance decreased with higher voltages.
Stainless steels are selected primarily for their excellent corrosion and oxidation resistance properties. One of the effective methods for manufacturing stainless steel parts of high quality and accuracy at low cost is through powder metallurgy. The demand for sintered stainless steels has
increased notably, in the recent years due to their promising properties, ease of fabrication, and are economical in production, especially where number of complex objects are involved.
Corrosion behaviour of sintered 316 l austenitic stainless steel compositesIAEME Publication
This document discusses corrosion behavior testing of sintered 316L austenitic stainless steel composites reinforced with metal oxide powders. Powders of Ga2O3, Nb2O5, and ZrO2 were added at 1-3% by weight to 316L stainless steel powder. The mixtures were sintered at 1250°C and analyzed using SEM and Tafel polarization testing. SEM showed increased porosity with higher melting point oxides like ZrO2. Tafel testing found composites had higher corrosion rates than plain 316L, with 3% Nb2O5 showing the lowest rate due to enhanced densification from liquid phase formation during sintering. Overall, reinforcement
AN APPROACH FOR ENERGY CONSERVATION ON PARTIALLY LATERISED KHONDALITE ROCKS U...IAEME Publication
Partially Lateritised Khondalite (PLK) rocks are the bauxite mining waste materials generated during mining and dumped at the mining site, create environmental pollution. These waste
rocks can be utilized as filler materials for different industrial applications after grinding to suitable mesh size. Thermal shock treatment on ore is used for grain boundary breakage and size reduction,due to thermal shock treatment the surface adsorbed gangue minerals also releases and expose new
surface area in the ore. Comminution study is used after this treatment for further reduction in size.
Partially Lateritised Khondalite (PLK) rocks are the bauxite mining waste materials
generated during mining and dumped at the mining site, create environmental pollution. These waste
rocks can be utilized as filler materials for different industrial applications after grinding to suitable
mesh size. Thermal shock treatment on ore is used for grain boundary breakage and size reduction,
due to thermal shock treatment the surface adsorbed gangue minerals also releases and expose new
surface area in the ore. Comminution study is used after this treatment for further reduction in size.
In comminution study, ball mill has good selective grinding performance. This paper deals with the
effect of thermal shock treatment on grinding characteristics of PLK rock and the overall energy
savings achieved. Alumina based filler/ceramic materials were used in different industries. Thermal
shock of the samples was evaluated using water quench test. Surface deterioration level of samples
was monitored by image analysis before and after quenching. A total energy saving of the order of
52.8 % could be achieved when a sample preheated at 1123 K for 60 minutes followed by coldwater
quenching and grinding.
Ni ion release of ti o2 and tio2 hydroxylapatite composite coatings formedIAEME Publication
This document summarizes a study that investigated the effect of TiO2 and TiO2/HA composite coatings on nickel ion release from porous NiTi shape memory alloy implants. Porous NiTi samples were produced by powder metallurgy and coated using H2O2 oxidation to form TiO2 and a combined H2O2/KOH treatment followed by immersion in simulated body fluid to form a TiO2/HA composite coating. Nickel ion release testing in saline solution found that TiO2 coating alone was insufficient to reduce nickel ion levels below safety thresholds, but the TiO2/HA composite coating was able to maintain lower nickel ion levels over time. The coatings were characterized using XRD to analyze phase composition.
Study on hardening mechanisms in aluminium alloysIJERA Editor
The Al-Zn-Mg alloys are most commonly used age-hardenable aluminium alloys. The hardening mechanism is
further enhanced in addition of Sc. Sc additions to aluminium alloys are more promising. Due to the
heterogeneous distribution of nano-sized Al3Sc precipitates hardening effect can be accelerated. Mainly,
highlight on hardening mechanism in Al-Zn-Mg alloys with Sc effect is to study. In addition, several
characterisations have been done to age-hardening measurements at elevated temperatures from 120oC to 180
oC. The ageing kinetics has also been calculated from Arrhenius equation. Furthermore, friction stir processing
(FSP) can be introduced to surface modification process and hardened the cast aluminium alloys. In this study,
hardening mechanism can be evaluated by Vicker’s hardness measurement and mechanical testing is present
task.
Study on hardening mechanisms in aluminium alloysIJERA Editor
The Al-Zn-Mg alloys are most commonly used age-hardenable aluminium alloys. The hardening mechanism is
further enhanced in addition of Sc. Sc additions to aluminium alloys are more promising. Due to the
heterogeneous distribution of nano-sized Al3Sc precipitates hardening effect can be accelerated. Mainly,
highlight on hardening mechanism in Al-Zn-Mg alloys with Sc effect is to study. In addition, several
characterisations have been done to age-hardening measurements at elevated temperatures from 120oC to 180
oC. The ageing kinetics has also been calculated from Arrhenius equation. Furthermore, friction stir processing
(FSP) can be introduced to surface modification process and hardened the cast aluminium alloys. In this study,
hardening mechanism can be evaluated by Vicker’s hardness measurement and mechanical testing is present
task.
This document summarizes a study that investigated improving osseointegration of alumina/zirconia ceramic implants through fluoride surface treatment. Specifically, it discusses:
1) Fabricating alumina/zirconia composites and modifying their surface with SnF2 and NaBF4 treatments. Characterization showed the treatments incorporated fluoride onto the surface.
2) Evaluating the treatments in vitro with human fibroblast cultures, which showed better cell proliferation and layer formation on SnF2-treated surfaces.
3) Testing the treatments in vivo with rabbit femur implants, which revealed the SnF2 treatment resulted in better bone-implant contact after 6 weeks.
Electrochemical Synthesis of MoO3 Nanoparticles Effect of Temperature Convert...IJERA Editor
MoO3 nanorods were prepared by electrochemical reduction method using the tetra propyl ammonium bromide (TPAB) was structure directing agent in an organic medium viz. tetra hydro furan (THF) and acetonitrile (ACN) in 4:1 ratio and at current density 14mA &18 mA. The reduction process takes place under atmospheric condition over a period of 2 h. Dried sample was calcinated in muffle furnace at 500ºC. The parameters such as current density and concentration of stabilizers were used to control the size of nanorods. The synthesized MoO3 nanorods were characterized by using UV-Visible, FT-IR, XRD, SEM-EDS and TEM analysis techniques.
Corrosion Behaviour of 6061 Al-SiC Composites in KOH MediumEditor IJCATR
The present research work deals with the corrosion behaviour of 6061 Al-15% (vol) SiC(P) composites. The addition of the
reinforcement like SiC to Aluminium has been reported to decrease the corrosion resistance of the matrix due to several reasons, one
of them being galvanic action between the reinforcement and the matrix. In the present work, the corrosion behaviour of 6061 Al-15%
(vol) SiC(P) composites in KOH at different concentration (0.5M, 1M, 1.5M) and different temperature (300C, 350C, 400C, 450C, 500C)
was determined by Tafel extrapolation technique. The inhibition action of 8-Hydroxyquinoline on corrosion behaviour of 6061 Al-
15% (vol) SiC(P) composites in KOH at different concentration of inhibitor (200ppm, 400ppm); different concentration of medium
(0.5M, 1M,1.5M) and different temperature (300C, 350C, 400C, 450C, 500C) was investigated. The results indicate that corrosion rate
of Al-SiC composite in KOH increases as the concentration of medium increases and also as temperature of medium increases. The
results indicate that the inhibitor is moderately effective in inhibiting the corrosion of 6061 Al-15% (vol) SiC(P) composites. As the
inhibitor concentration increases, the corrosion rate decreases. The surface morphology of the metal surface was investigated using
scanning electron microscope (SEM). Activation energy was evaluated using Arrhenius equation, and enthalpy of activation and
entropy of activation values were calculated using transition state equation
The document investigates the effect of deep cryogenic treatment (DCT) on the microstructure and properties of an AE42 magnesium alloy. Key findings include:
1) DCT for 4-16 hours reduced the volume fraction of the brittle Al4RE phase in the alloy microstructure. The longest DCT time of 16 hours produced the lowest Al4RE content.
2) UTS and ductility increased with DCT, attributed to dissolution of the brittle Al4RE phase, while YS saw a marginal rise. The 16-hour DCT alloy achieved the best tensile properties.
3) Creep resistance decreased with DCT due to reduced amounts of the thermally stable Al
Microstructure and tribological properties of nanoparticulate wcIAEME Publication
The document summarizes a study on the microstructure and tribological properties of aluminum metal matrix composites reinforced with tungsten carbide nanoparticles. Nanoparticulate WC/Al composites were fabricated using vacuum melt processing. Sliding wear tests found that adding WC nanoparticles effectively reduced the frictional coefficient and wear rate of the composites compared to the unreinforced aluminum alloy. Examination of worn surfaces using SEM suggested the nanoparticles promote a positive rolling effect that improves the load carrying capacity of the nanocomposites.
This document summarizes a study on the effect of quenching media, heat treatment, and alloying elements on the properties of Al-Si-Mg alloys. The study prepared Al-Si-Mg alloys and studied how quenching in polymer solution or water, heat treatment, and adding alloying elements like B and Ti impacted properties like microhardness. Results showed that adding 0.15% B with 1% Ti improved microhardness by 57% compared to the base alloy. Quenching in polymer solution also improved thermal stability during aging at 175°C compared to water quenching. Mechanical properties were measured using ultrasound techniques and microstructure was examined using optical microscopy.
Characterization and Dielectric Study of Mihaliccik Tremoliteijtsrd
The document describes a study characterizing and analyzing the dielectric properties of tremolite, a calcium magnesium silicate mineral, collected from Mihaliccik, Turkey. X-ray diffraction, energy dispersive spectroscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy were used to analyze the mineral's chemical composition and structure. The mineral was found to contain mostly silicon dioxide, magnesium oxide, and calcium oxide with minor amounts of aluminum oxide and calcite impurity. Dielectric measurements were performed on tremolite samples fired at different temperatures to investigate how firing affects permittivity and loss tangent.
Studies of the Atomic and Crystalline Characteristics of Ceramic Oxide Nano P...albertdivis
In the present study, some transition metal oxides (Zinc oxide, iron oxide and copper oxide) which are widely used in the fabrication of electronic devices were selected and subjected to biofield treatment.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Electrospun Nanofibers Reinforced Aluminium Matrix Composites, A Trial to Imp...IJAMSE Journal
A comparison between TiO2 nanofibers and carbon nanofibers as fibers reinforced metal matrix composites with respect to mechanical properties improvements have been made in this paper. Al and Mg have been chosen as metal matrices. The used carbon and ceramic nanofibers (Titanium Oxide) were successfully synthesized using electrospinning technique. Various weight percentage of calcined
electrospun TiO2 and carbon nanofibers (1, 3, 5 and 10%) were mixed with metal matrix and fabricated by route of powder metallurgy using High Frequency Induction heat Sintering (HFIHS). Mechanical properties of the sintered composites have been investigated. The manufactured pellets were tested for compression test, hardness and microstructures by the field emission scanning electron microscopes (FESEM), which reveals the homogeneous distribution of nanofibers in the Al/Mg matrices. In addition,
energy-dispersive X-ray spectroscopy (EDS) was employed to obtain the chemical analysis of each composite. The result shows that, the ultimate compressive strength increased to 415 MPa at 5% TiO2, which is 13.5% more than the pure Al. The hardness increased up to 64% in case of using the ceramic nanofibers as reinforcement. While using CNFs as reinforcement to the Al matrix deteriorates the
mechanical properties.
Similar to SIMONA CAVALU_Surface Modification of Alumina/ Zirconia Ceramics Upon Different Fluoride-Based Treatments (20)
Cavalu Simona_PMMA/Mg3Al2(SiO4)3 BONE CEMENTS: PRODUCTION, STRUCTURAL CHARACT...Simona Cavalu
The document discusses the production and characterization of acrylic bone cements reinforced with 5% magnesium aluminosilicate (Mg3Al2(SiO4)3). Structural analysis using FTIR and XRD showed the inclusion of the Mg3Al2(SiO4)3 crystalline phase within the PMMA polymer matrix. SEM images revealed the additive created a porous structure in PMMA, facilitating hydroxyapatite formation in vitro. Biocompatibility tests with human fibroblasts showed cell attachment and proliferation on specimens with and without the magnesium aluminosilicate; no cytotoxic effects were observed. The study aims to improve the mechanical and bioactive properties of acrylic bone cements.
SIMONA CAVALU_Biomaterials and regenerative biomedicineSimona Cavalu
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New evidences of key factors involved in “silent stones” ethiopathogenesis an...Simona Cavalu
The knowledge of the key factors involved in ethiopathogenesis of the gallstones disease requires chemical, structural and elemental composition analysis.
The knowledge of the key factors involved in ethiopathogenesis of the gallstones disease requires chemical, structural and elemental composition analysis
This document summarizes research on PMMA/Ag2O acrylic bone cement coated with collagen to improve biomineralization, biocompatibility, and antibacterial properties. Collagen was electrodeposited on cement samples containing 0.5%, 1%, and 2% silver oxide. FTIR analysis showed collagen deposition depended on silver content. In vitro tests in simulated body fluid revealed silver ion release and mineralization of hydroxyapatite on surfaces over 3 weeks. Antimicrobial tests showed inhibition of E. coli and S. aureus growth, with effectiveness depending on silver content.
This document summarizes research on the adsorption behavior of hyaluronidase enzyme onto silver nanoparticles and polymethyl methacrylate (PMMA) bone substitute surfaces. Surface-enhanced Raman scattering (SERS) and infrared (IR) spectroscopy techniques were used to analyze the adsorption. SERS spectra of hyaluronidase adsorbed to silver nanoparticles showed well-resolved Raman signals and indicated oxygen adsorption from functional groups. IR analysis of PMMA incubated with hyaluronidase showed shifts in amide band positions, suggesting changes to secondary structure upon adsorption. Band deconvolution and fitting of amide peaks revealed decreases in α-helix and β-sheet content for adsorbed hyaluronidase, with increases
This document summarizes research on the adsorption behavior of hyaluronidase enzyme onto silver nanoparticles and polymethyl methacrylate (PMMA) bone substitute surfaces. Surface-enhanced Raman scattering (SERS) and infrared (IR) spectroscopy techniques were used to analyze the adsorption. SERS spectra of hyaluronidase adsorbed to silver nanoparticles showed well-resolved Raman signals and suggested oxygen adsorption from functional groups. IR analysis of PMMA incubated with hyaluronidase showed shifts in amide band positions, indicating changes to secondary structure upon adsorption. Band deconvolution and fitting of amide peaks revealed decreases in α-helix and β-sheet content for adsorbed hyaluronidase, with increases
SIMONA CAVALU_ Bone Cement silver joam2007Simona Cavalu
This study evaluated two types of silver-doped bone cement composites for their properties and ability to release silver ions with antibacterial effects. Electrochemical measurements showed both composites reduced calcium ion concentration in simulated body fluid over 14 days, with one composite releasing more silver ions within 5 hours. Scanning electron microscopy images revealed both composites developed hydroxyapatite crystal structures on their surfaces after 14 days, indicating bioactivity. Infrared spectroscopy confirmed mineral deposition and showed one composite absorbed more water over time. The antibiotic-containing composite showed greater mineralization and formation of a calcium phosphate layer, suggesting it may be more suitable for applications requiring bone growth.
This document summarizes a study that compares the microstructure, bioactivity, and biocompatibility of two types of acrylic bone cements: BIOLOS3® and ANTIBIOTIC SIMPLEX®. Electrochemical measurements, SEM imaging, and FTIR spectroscopy were used to analyze the materials after incubation in simulated body fluid for up to 34 days. The results showed that ANTIBIOTIC SIMPLEX® developed a more intense mineralization layer on its surface, as evidenced by greater calcium phosphate formation and water uptake. Hemolysis testing also indicated ANTIBIOTIC SIMPLEX® had better blood compatibility. In conclusion, the antibiotic-containing cement demonstrated superior in vitro bioactivity and bi
Introducing BoxLang : A new JVM language for productivity and modularity!Ortus Solutions, Corp
Just like life, our code must adapt to the ever changing world we live in. From one day coding for the web, to the next for our tablets or APIs or for running serverless applications. Multi-runtime development is the future of coding, the future is to be dynamic. Let us introduce you to BoxLang.
Dynamic. Modular. Productive.
BoxLang redefines development with its dynamic nature, empowering developers to craft expressive and functional code effortlessly. Its modular architecture prioritizes flexibility, allowing for seamless integration into existing ecosystems.
Interoperability at its Core
With 100% interoperability with Java, BoxLang seamlessly bridges the gap between traditional and modern development paradigms, unlocking new possibilities for innovation and collaboration.
Multi-Runtime
From the tiny 2m operating system binary to running on our pure Java web server, CommandBox, Jakarta EE, AWS Lambda, Microsoft Functions, Web Assembly, Android and more. BoxLang has been designed to enhance and adapt according to it's runnable runtime.
The Fusion of Modernity and Tradition
Experience the fusion of modern features inspired by CFML, Node, Ruby, Kotlin, Java, and Clojure, combined with the familiarity of Java bytecode compilation, making BoxLang a language of choice for forward-thinking developers.
Empowering Transition with Transpiler Support
Transitioning from CFML to BoxLang is seamless with our JIT transpiler, facilitating smooth migration and preserving existing code investments.
Unlocking Creativity with IDE Tools
Unleash your creativity with powerful IDE tools tailored for BoxLang, providing an intuitive development experience and streamlining your workflow. Join us as we embark on a journey to redefine JVM development. Welcome to the era of BoxLang.
QA or the Highway - Component Testing: Bridging the gap between frontend appl...zjhamm304
These are the slides for the presentation, "Component Testing: Bridging the gap between frontend applications" that was presented at QA or the Highway 2024 in Columbus, OH by Zachary Hamm.
What is an RPA CoE? Session 2 – CoE RolesDianaGray10
In this session, we will review the players involved in the CoE and how each role impacts opportunities.
Topics covered:
• What roles are essential?
• What place in the automation journey does each role play?
Speaker:
Chris Bolin, Senior Intelligent Automation Architect Anika Systems
Connector Corner: Seamlessly power UiPath Apps, GenAI with prebuilt connectorsDianaGray10
Join us to learn how UiPath Apps can directly and easily interact with prebuilt connectors via Integration Service--including Salesforce, ServiceNow, Open GenAI, and more.
The best part is you can achieve this without building a custom workflow! Say goodbye to the hassle of using separate automations to call APIs. By seamlessly integrating within App Studio, you can now easily streamline your workflow, while gaining direct access to our Connector Catalog of popular applications.
We’ll discuss and demo the benefits of UiPath Apps and connectors including:
Creating a compelling user experience for any software, without the limitations of APIs.
Accelerating the app creation process, saving time and effort
Enjoying high-performance CRUD (create, read, update, delete) operations, for
seamless data management.
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Charlie Greenberg, host
Must Know Postgres Extension for DBA and Developer during MigrationMydbops
Mydbops Opensource Database Meetup 16
Topic: Must-Know PostgreSQL Extensions for Developers and DBAs During Migration
Speaker: Deepak Mahto, Founder of DataCloudGaze Consulting
Date & Time: 8th June | 10 AM - 1 PM IST
Venue: Bangalore International Centre, Bangalore
Abstract: Discover how PostgreSQL extensions can be your secret weapon! This talk explores how key extensions enhance database capabilities and streamline the migration process for users moving from other relational databases like Oracle.
Key Takeaways:
* Learn about crucial extensions like oracle_fdw, pgtt, and pg_audit that ease migration complexities.
* Gain valuable strategies for implementing these extensions in PostgreSQL to achieve license freedom.
* Discover how these key extensions can empower both developers and DBAs during the migration process.
* Don't miss this chance to gain practical knowledge from an industry expert and stay updated on the latest open-source database trends.
Mydbops Managed Services specializes in taking the pain out of database management while optimizing performance. Since 2015, we have been providing top-notch support and assistance for the top three open-source databases: MySQL, MongoDB, and PostgreSQL.
Our team offers a wide range of services, including assistance, support, consulting, 24/7 operations, and expertise in all relevant technologies. We help organizations improve their database's performance, scalability, efficiency, and availability.
Contact us: info@mydbops.com
Visit: https://www.mydbops.com/
Follow us on LinkedIn: https://in.linkedin.com/company/mydbops
For more details and updates, please follow up the below links.
Meetup Page : https://www.meetup.com/mydbops-databa...
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Blogs: https://www.mydbops.com/blog/
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"Frontline Battles with DDoS: Best practices and Lessons Learned", Igor IvaniukFwdays
At this talk we will discuss DDoS protection tools and best practices, discuss network architectures and what AWS has to offer. Also, we will look into one of the largest DDoS attacks on Ukrainian infrastructure that happened in February 2022. We'll see, what techniques helped to keep the web resources available for Ukrainians and how AWS improved DDoS protection for all customers based on Ukraine experience
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Read More - https://bit.ly/3VKly70
This talk will cover ScyllaDB Architecture from the cluster-level view and zoom in on data distribution and internal node architecture. In the process, we will learn the secret sauce used to get ScyllaDB's high availability and superior performance. We will also touch on the upcoming changes to ScyllaDB architecture, moving to strongly consistent metadata and tablets.
inQuba Webinar Mastering Customer Journey Management with Dr Graham HillLizaNolte
HERE IS YOUR WEBINAR CONTENT! 'Mastering Customer Journey Management with Dr. Graham Hill'. We hope you find the webinar recording both insightful and enjoyable.
In this webinar, we explored essential aspects of Customer Journey Management and personalization. Here’s a summary of the key insights and topics discussed:
Key Takeaways:
Understanding the Customer Journey: Dr. Hill emphasized the importance of mapping and understanding the complete customer journey to identify touchpoints and opportunities for improvement.
Personalization Strategies: We discussed how to leverage data and insights to create personalized experiences that resonate with customers.
Technology Integration: Insights were shared on how inQuba’s advanced technology can streamline customer interactions and drive operational efficiency.
"$10 thousand per minute of downtime: architecture, queues, streaming and fin...Fwdays
Direct losses from downtime in 1 minute = $5-$10 thousand dollars. Reputation is priceless.
As part of the talk, we will consider the architectural strategies necessary for the development of highly loaded fintech solutions. We will focus on using queues and streaming to efficiently work and manage large amounts of data in real-time and to minimize latency.
We will focus special attention on the architectural patterns used in the design of the fintech system, microservices and event-driven architecture, which ensure scalability, fault tolerance, and consistency of the entire system.
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Mobile Security Framework - MobSF is a free and open source automated mobile application security testing environment designed to help security engineers, researchers, developers, and penetration testers to identify security vulnerabilities, malicious behaviours and privacy concerns in mobile applications using static and dynamic analysis. It supports all the popular mobile application binaries and source code formats built for Android and iOS devices. In addition to automated security assessment, it also offers an interactive testing environment to build and execute scenario based test/fuzz cases against the application.
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Using MobSF for static analysis of mobile applications.
Interactive dynamic security assessment of Android and iOS applications.
Solving Mobile app CTF challenges.
Reverse engineering and runtime analysis of Mobile malware.
How to shift left and integrate MobSF/mobsfscan SAST and DAST in your build pipeline.
Northern Engraving | Nameplate Manufacturing Process - 2024Northern Engraving
Manufacturing custom quality metal nameplates and badges involves several standard operations. Processes include sheet prep, lithography, screening, coating, punch press and inspection. All decoration is completed in the flat sheet with adhesive and tooling operations following. The possibilities for creating unique durable nameplates are endless. How will you create your brand identity? We can help!
As AI technology is pushing into IT I was wondering myself, as an “infrastructure container kubernetes guy”, how get this fancy AI technology get managed from an infrastructure operational view? Is it possible to apply our lovely cloud native principals as well? What benefit’s both technologies could bring to each other?
Let me take this questions and provide you a short journey through existing deployment models and use cases for AI software. On practical examples, we discuss what cloud/on-premise strategy we may need for applying it to our own infrastructure to get it to work from an enterprise perspective. I want to give an overview about infrastructure requirements and technologies, what could be beneficial or limiting your AI use cases in an enterprise environment. An interactive Demo will give you some insides, what approaches I got already working for real.
Keywords: AI, Containeres, Kubernetes, Cloud Native
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Essentials of Automations: Exploring Attributes & Automation ParametersSafe Software
Building automations in FME Flow can save time, money, and help businesses scale by eliminating data silos and providing data to stakeholders in real-time. One essential component to orchestrating complex automations is the use of attributes & automation parameters (both formerly known as “keys”). In fact, it’s unlikely you’ll ever build an Automation without using these components, but what exactly are they?
Attributes & automation parameters enable the automation author to pass data values from one automation component to the next. During this webinar, our FME Flow Specialists will cover leveraging the three types of these output attributes & parameters in FME Flow: Event, Custom, and Automation. As a bonus, they’ll also be making use of the Split-Merge Block functionality.
You’ll leave this webinar with a better understanding of how to maximize the potential of automations by making use of attributes & automation parameters, with the ultimate goal of setting your enterprise integration workflows up on autopilot.
2. Introduction
Ceramics have a great potential in the biomedical
field, thanks to their biocompatibility, strength, and
wear resistance. The two dominant ceramic materials in
clinical use today as bearing surfaces are still alumina
(Al2O3) and zirconia (ZrO2).1–3
Alumina exhibits
excellent hardness and wear properties; fracture tough-
ness values are lower than those of the metals used in
orthopedic surgery. However, it is a brittle material,
with low resistance to the propagation of cracks. Zirco-
nia was introduced to overcome the limitations of alu-
mina. It is well known that transformation toughening
improves the mechanical properties of zirconia ceram-
ics, as their major drawback is the strength reduction,
due to an unfavorable tetragonal to monoclinic mar-
tensitic phase transformation during the contact with
physiological fluids.4–7
Zirconia, in contrast to alumina,
is an unstable material, existing in three crystalline
phases: monoclinic, tetragonal, and cubic. The tetrago-
nal phase that is the most resistant tends to transform
into the monoclinic phase under certain conditions
(aging, thermal treatment). The addition of stabilizing
materials such as Y2O3 or CeO2 during manufacture
can control the phase transformation of zirconia.5–7
Therefore, the ideal ceramic for orthopedic and dental
applications is a high-performance biocomposite mate-
rial that combines the excellent material properties of
alumina in terms of chemical stability, hydrothermal
stability, biocompatibility, and extremely low wear and
of zirconia with its superior mechanical strength and
fracture toughness.8–11
On the other hand, the surfaces
modification and postsynthesis treatment also influence
the performances of the bioceramics designed to dental
applications.12,13
It was demonstrated that the adminis-
tration of complex fluorides as compared with NaF
suggests the possibility of using them as effective agents
in dental caries prevention in human populations.14,15
For example, stannous fluoride converts the calcium
mineral apatite into fluorapatite, which makes tooth
enamel more resistant to bacteria generated acid attacks.
In toothpastes containing calcium minerals, sodium
fluoride becomes ineffective over time, while stannous
fluoride remains effective in strengthening tooth
enamel. Stannous fluoride has been shown to be more
effective than sodium fluoride in reducing the incidence
of dental caries and controlling gingivitis.16
Further
aspects related to the action of these new bioceramics
upon different surface treatments on dentinal tissue are
to be analyzed, to be properly used by professionals, so
that they can make the best of properties during clini-
cal applications.17
Even if increasing attention has been
paid to elucidating the influence of fluoride chemistry
in tooth mineralization, there are also some debates
about the use of fluoride in osteoporosis treatment, par-
ticularly concerning the beneficial effects on bone mass
and quality.18
NaF has been known to be one of the
most effective agents for the treatment of vertebral oste-
oporosis by its stimulating effect on new bone forma-
tion.19
In this study, we are focused on the possible
beneficial effect of fluorination with respect to dental
bioceramics. The surface modifications of alumina and
alumina/zirconia bioceramics are investigated upon dif-
ferent treatments with sodium tetrafluoroborate and
stannous fluoride, respectively. The proposed bioceram-
ics are designed for orthopedic or dental implants,
being prepared by Spark Plasma Sintering.20
Using
complementary spectroscopic tools such as Attenuated
Total Reflection Fourier Transform Infrared Spectros-
copy (ATR FTIR) and X-rays Photoelectron Spectros-
copy (XPS), the chemical changes on the surface
induced by fluoride treatment are discussed in terms of
their effectiveness.
Materials and Methods
Preparation and Structural Characterization of
Alumina and Alumina/Zirconia Specimens
Al2O3 (Baikowski grade SM8, an average particle
size of 0.6 lm), 3 mol% yttria stabilized ZrO2 (3YSZ,
Tosoh grade, an average particle size of 0.1 lm), and
TiO2 (Merck, an average particle size of 1 lm) pow-
ders were used as starting materials. The raw materials
were weighed in appropriate quantities, ball milled in
ethanol for 24 h and then dried. A graphite die 5 mm
inner diameter was used in the sintering process. Al2O3
and Al2O3–3YSZ composites with 5% (wt) TiO2 addi-
tion were prepared using a spark plasma sintering
method (SPS apparatus SPS-7.40 MK-VII Syntex, Fuji
Electronic Industrial, Saitama, Japan) at 1350°C for
5 min with a heating rate of 100°C/min in vacuum,
under a pressure of 40 MPa, resulting three different
specimens with the chemical composition as follows:
specimen 1- monolithic Al2O3; specimen
2- 80%Al2O3 À 20%3YSZ; specimen 3- 80%Al2O3
À 20%3YSZ + 5%TiO2. The specific Al2O3/3YSZ
ratio was chosen because it was previously demon-
2 International Journal of Applied Ceramic Technology—Cavalu, et al. 2013
3. strated that zirconia has a reinforcing effect up to
30%.20
In the same time, as a result of our optimiza-
tion studies (not presented here), it was found that
5 wt% TiO2 addition had a remarkable effect with
respect to their mechanical properties. Structural char-
acterization of the specimens was made by FTIR spec-
troscopy (BXII spectrometer using K Br pellet
technique, resolution of 2/cm, at room temperature;
Perkin-Elmer, Waltham, MA), and X-ray diffraction
analysis carried out with a Shimadzu XRD- 600 diffrac-
tometer, using Cu-Ka radiation (k = 1.5418
A) with
Ni-filter. The morphology of the specimen surface (on
fracture) was investigated by scanning electron micros-
copy (JSM 7000F, JEOL, Tokyo, Japan).
Fluoride Surface Treatment and Surface
Investigation of the Specimens
High purity stannous fluoride (Tin II fluoride) and
sodium tetrafluoroborate (Sigma Aldrich, St. Louis,
MO) were used to prepare saturated solutions (0.4 g/
mL and 1 g/mL, respectively) for surface treatment of
the specimens by conventional anodization during 2 h
at 12V. Upon the anodization treatment, the specimens
were ultrasonically treated for 90 min to remove the
deposits, then air-dried. The modifications of samples
surface upon both fluoride treatment were investigated
by ATR FTIR spectroscopy using ATR Miracle device
(single reflection with ZnSe crystal) and XPS measure-
ments performed with SPECS PHOIBOS 150 MCD
system equipped with monochromatic Al-Ka source
(250W, hm = 1486.64 eV) and Epass = 50 eV, with a
resolution of 1 eV/step. The vacuum in the analysis
chamber during the measurements was kept in the
range 10À9
–10À10
mbar.
All binding energies were referenced to the C 1 s
peak arising from adventitious carbon at 284.6 eV. The
peak areas combined with the appropriate sensitivity
factors allowed to quantify the elemental composition
at the surface. The depth of analysis was about 5 nm.
Results
Structural Investigation of the Specimens by SEM,
FTIR, XRD Spectroscopy
The morphological characteristics and the details
of the fractured surfaces of the proposed specimens
were evidenced by SEM analysis and presented in
Fig. 1. The details including the size and shape of the
alumina (micron size, gray) and zirconia (submicron,
bright white) grains clearly demonstrate that Spark
Plasma Sintering makes possible the densification of
Al2O3 based composites at a lower temperature and in
a shorter time compared with some other conventional
techniques.9,11,21
Furthermore, the microstructure and
grain size can be controlled by a fast heating rate and
shorter processing time. The structural details were
observed from the analysis of the FTIR spectra
recorded between 400 and 1400/cm and presented in
Fig. 2. The FTIR spectra are dominated by absorption
lines arising from Al2O3 phase (1088/cm, 780 and
797/cm). The addition of zirconia phase clearly modi-
fies the relative intensity of these bands. The vibration
of Zr-O bond in tetragonal phase is visible at 518 and
580/cm. A superposition of the characteristic absorp-
tion bands occurs in the spectral region 500–650/cm
upon TiO2 addition to alumina/zirconia matrix and, as
a consequence, Ti-O vibration band cannot be distin-
guished. The XRD patterns of the proposed specimens
are presented in Fig. 3 showing the characteristic peaks
of a-corundum (JCPDS: 30-0415) and tetragonal
zirconia (JCPDS: 42-1164). The reflection lines occur-
ring from crystallographic planes related to a-corundum
are clearly marked at 2h = 25.6; 35.2; 37.9; 43.4;
57.5; 61.3; 66.4; 68.2; 76.9, and 80.7°,
while the iden-
tification of tetragonal zirconia is assigned to
2h = 29.9; 49.9; 59.7, and 62.5° in specimen 2 and 3.
The pattern show highest tetragonal intensities of (111)
planes at 2h = 29.9° and (220) planes at 2h = 59.7°
and lower intensities of (113) and (311) at 2h = 62.5°.
The presence of rutile TiO2 is assigned to small peaks
at 2h = 26.4 and 36° in specimen 3. No monoclinic
phase of ZrO2 was detected from the XRD results.
Surface Modification Upon Fluoride Treatments
Investigated by ATR FTIR and XPS Spectroscopy
In Fig. 4a are presented the vibrational ATR FTIR
details of both fluoride as received from the supplier
(crystalline powder). The fingerprints of SnF2 are
observed at 492, respectively, 548/cm and assigned to
symmetric and asymmetric stretch mode, whereas for
NaBF4, the marker bands in the selected region are
443, 472, 498, and 575/cm, as the [BF4] species
belongs to a symmetry group with four normal modes
of vibration. For the wide range of tetrafluoroborates
and other [XF4] compounds (X = C, Si, Al, Ge, N, P,
www.ceramics.org/ACT Alumina Zirconia Bioceramics 3
4. etc.), the position of the normal modes follows the
trend: m3 m1 m4 m2.
Upon the fluoride treatment, the surface of the
specimens was strongly affected as revealed by the ATR
FTIR spectra presented in Fig. 4(b-d). The marker
bands of both SnF2 and NaBF4 can be observed along
with the characteristic features of Al-O stretching vibra-
tions at 435/cm and, respectively, Zr-O at 526/cm.
The survey XPS spectra recorded on the surface of the
specimens before and after fluoride treatment are pre-
sented comparatively in Fig. 5. The main photoelectron
peaks in the spectra of the specimens before treatments
are assigned to Al 2s (117.9 eV), Al 2p (74.3 eV), O
1s (531.8 eV) (specimen 1), Zr 3d (180 eV), and Ti
2p (456 eV) (specimen 2 and 3 respectively). After
SnF2 treatment, a strong peak at 487.1 eV indicates
the contribution of Sn 3d electrons, while the presence
of fluorine is proved by F 1s photoelectrons peak at
685 eV. These marker peaks are strongly visible for all
the specimens, but as presented in Table 1, the atomic
concentration of the elements shows a higher percent
of Sn on the surface of composites (specimen 2 and 3)
(a) (b)
(c) (d)
(e) (f)
Fig. 1. SEM micrographs recorded on the fractured surface of the specimens, with different details and magnifications along with the
EDAX spectrum: specimen 1 (a, b); specimen 2 (c, d); and specimen 3(e, f).
4 International Journal of Applied Ceramic Technology—Cavalu, et al. 2013
5. compared with the monolithic Al2O3. With respect to
the NaBF4 treatment, the marker peaks in this case are
F1s at 685.7 eV and Na 1s at 1072 eV, but this treat-
ment shows a less effectiveness compared with SnF2.
Anyway, the maximum effect in this case is observed
toward the specimen 3. The results obtained by both
XPS and ATR FTIR spectroscopy show a good correla-
tion from the standpoint of qualitative and quantitative
aspects.
Discussion
To overcome the low toughness of alumina and
the aging sensitivity of zirconia, alumina-zirconia, com-
posites have been proposed for biomedical applications.
The toughening mechanism in ZTA ceramics (zirconia
toughened alumina) is related to structural properties
of these materials, conferred especially by zirconia due
to its versatile structural properties. The details pre-
sented in Fig. 1 demonstrate that the presence of zirco-
nia as a second phase is beneficial with respect to the
inhibition of grain growth. Fine zirconia particles
located on the boundaries inhibit the movement and
prevent the grain growth of alumina (about 50%
reduction in alumina grain size was observed). It has
been previously demonstrated that the zirconia addition
to alumina matrix promotes composites with higher
densities, higher flexural strength, and fracture tough-
ness.11,21
Moreover, as shown in Fig. 1 (e, f), adding
TiO2 particles is more effective, as the size of alumina
grains is reduced by comparison with Fig.1 (c, d). A
special behavior with respect to the evolution of the
structural units present in these samples was observed
from the analysis of the FTIR spectra recorded between
400 and 1400 cm (Fig. 2). The correlation between IR
(a)
(b)
(c)
Fig. 2. Fourier transform infrared spectroscopy (FTIR) spectra
of alumina and alumina-zirconia specimens: (a) specimen 1, (b)
specimen 2, and (c) specimen 3.
0 10 20 30 40 50 60 70 80 90 100
0
500
1000
1500
2000
T
T
A
A
AZ
AA
A
Z
A
A
Z
Z
Z
A
A
A
A
AA
AA
A
(b)
(a)
Intensity(a.u.)
2 theta (degrees)
(c)
Fig. 3. XRD patterns of specimen 1 (a), specimen 2 (b), and specimen 3 (c).
www.ceramics.org/ACT Alumina Zirconia Bioceramics 5
6. absorption bands and different types of aluminate poly-
hedral is based on previous results obtained for alumi-
nate crystals.22–25
The Al-O stretching vibrations of tetrahedral AlO4
groups are related to the broad, strong band at 1088/
cm with the shoulder at 1168/cm and to the doublet at
780 and 797/cm. The aluminum atoms are differently
coordinated, usually by four or six oxygen atoms, and
less likely by five oxygens. The absorption bands and
shoulders recorded in the spectral region between 465
and 648/cm are assigned to six coordinated aluminum
which are associated with stretching modes of AlO6
octahedra. The addition of zirconia phase clearly modi-
fies the relative intensity of these bands. In some previ-
ous studies on zirconia structural characteristics, the
authors mentioned absorption bands at 410, 445, 500,
572, 740, 1104, and 1187/cm.26
Other studies27,28
reported FTIR bands at 740/cm corresponding to Zr-O
vibrations in monoclinic ZrO2 and bands at 510/cm
and 590/cm corresponding to Zr-O vibrations in
tetragonal ZrO2. In our spectra, the vibrations of Zr-O
in tetragonal phase are visible at 518 and 580/cm.
Moreover, upon TiO2 addition to alumina-zirconia
matrix, the relative intensity of 648/617/cm is consider-
ably modified, as a superposition of the characteristics
absorption bands occurs in this region.29
The analysis
of XRD patterns (Fig. 3) led to results that are in
agreement with previously reported studies with respect
(a) (b)
(c) (d)
Fig. 4. (A) Attenuated total reflection fourier transform infrared spectroscopy (ATR FTIR) spectra of SnF2 and NaBF4 powders as
received from the supplier (a), and ATR FTIR spectra recorded on specimen surface before and after treatment using SnF2 and NaBF4:
specimen 1 (b), specimen 2 (c), and specimen 3 (d).
6 International Journal of Applied Ceramic Technology—Cavalu, et al. 2013
7. to the effect of zirconia content on properties of Al2O3
–ZrO2 (Y2O3) composites.30–32
As expected, the con-
straint exerted by the alumina matrix on the zirconia
particles maintains them in tetragonal state. In the same
time, the intensity ratio of the main peaks for alumina
and zirconia is in agreement with the ZrO2 content in
samples. The results demonstrate that the high density
of the matrix correlated with the optimization of the
zirconia particles microstructure can assure the parame-
ters of better material performances.33
According to their interaction with surrounding
tissue, bioceramics can be categorized as “bioinert” or
“bioactive.” Tough and strong ceramics like zirconia,
alumina, or alumina-zirconia composites are not capa-
ble of creating a biologically adherent interface layer
with bone due to the chemically inert nature of these
two stable oxides.34
It has been demonstrated that sur-
face morphology and bone–implant interactions deter-
mine the predictability of endosseous implant bone
integration.13,35
Different surface treatments such as
Table 1. Atomic concentration of Sn, F, and Na on
the surface of the specimens after fluoride treatment
determined from X-rays photoelectron spectroscopy
(XPS) survey spectra
Specimen
Elemental composition (at %)
Sn
F
NaSnF4 NaBF4
1 3.4 4.9 3.2 2.1
2 12.8 3.9 2.4 1.9
3 12.4 3.3 6.8 4.2
1200 1000 800 600 400 200 0
O1s
F1s
O2s
Al2s
Al2p
F1s
Al2p
OAuger
Na1s
O1s
C1s
Intensity(a.u)
Binding Energy (eV)
Sn3d
Al2s
O2s
Sn4dF2sNa2p
Specimen 1
SnF2
NaBF4
1200 1000 800 600 400 200 0
F1s
Al2s
Zr3d
Al2p
C1s
N1s
O1s
Sn4dZr4pF2s
Sn3p
1
Sn3d
Zr3d
N1s
F1s
Al2p
Na1s
O1s
C1s
Intensity(a.u)
Binding Energy (eV)
Sn3p
3
Al2s
OAuger
Zr4p
Specimen 2
SnF2
NaBF4
1200 1000 800 600 400 200 0
Sn4d,Zr4p,F2s,Na2p,Ti3p
B1s
FAuger
Al2s
Al2p
OAuger
F1s
Al2p
C1s
Ti2p
O1sO1s
Sn3p
1
Sn3d
F1s
Na1s
O1s
C1s
Intensity(a.u.)
Binding energy (eV)
Al2s
Zr3d
Ti2p
OAuger
Sn3p
3
SnAuger
Specimen 3
SnF2
NaBF4
(a) (b)
(c)
Fig. 5. X-rays photoelectron spectroscopy (XPS) survey spectra of specimen 1 (a), specimen 2 (b), and specimen 3 (c) before and after
treatment with SnF2 and NaBF4.
www.ceramics.org/ACT Alumina Zirconia Bioceramics 7
8. surface blasting or acid etching can increase the rate
and amount of new bone formation on the implant
surface. Sandblasting procedure may be performed
using either medium or large grit Al2O3 particles,
whereas acid-etching process can employ hydrofluoric
acid/nitric acid. Some authors36
evaluated and reported
the apatite-forming ability of a zirconia/alumina nano-
composite (10Ce-TZP/Al2O3) in SBF as a result of the
formation of ZrAlOH groups on the surface after
chemical treatment of the material in H3PO4, H2SO4,
HCl, and NaOH at 95°C for 4 days. Hence, many dif-
ferent techniques are currently in use to condition the
surfaces of abutments and fixtures of implants.37
Sev-
eral in vitro and in vivo studies have demonstrated that
the surface structure of implant abutments influences
both the orientation and proliferation of connective tis-
sue cells and inhibits epithelial downgrowth.38
In this
study, the surface modifications of the proposed alu-
mina and alumina/zirconia ceramics upon different
fluoride treatments are emphasized by complementary
techniques ATR FTIR and XPS spectroscopy. The
ATR FTIR spectra recorded on the specimens’ surface
(Fig. 4) clearly demonstrate that the surface is being
treated, emphasized by the presence of the marker
bands of both SnF2 and NaBF4 according to their spe-
cific vibration modes.39,40
By comparing with the
FTIR spectra of the specimens before fluoride treat-
ments (Fig. 2), the changes are evident. On the other
hand, taking account of the relative intensities of the
fluoride marker bands with respect to each specimen,
one can observe that, even after the removal of the
surface deposits, different fluoride concentration can
be detected on the surface. To obtain more details,
XPS survey spectra were recorded on the specimens’
surface before and after fluoride treatment (Fig. 5). In
some previous studies, XPS has been successfully used
to investigate the surface chemistry of the commercial
zirconia implants, showing substantial differences from
bulk.41
After sandblasting procedure performed by the
manufacturer, large differences in the XPS elemental
composition were identified for the collar and threaded
root of the commercial implants. These values may
imply that the residual Al2O3 particles are aggregated
in a thinner superficial layer. Other studies related to
XPS analysis of tin oxide on glass surface demon-
strated the presence of several valences of tin that gave
rice to Sn 3d3/2 and Sn 3d5/2 typical peaks at
494.70 eV and 486.24 eV, along with two additional
peaks at 493.13 eV and 484.71 eV.42–45
The binding
energy of the doublet at 495.5 and 487.1 eV is in
good agreement with the data reported for In2O3–
SnO2 films prepared using as starting material for tin
oxide the hydrated stannic chloride (SnCl4 9
5H2O).43
By comparing the results presented in Fig. 5
(a-c), we can notice that all the specimens present a
high sensitivity to the SnF2 treatment. These results
are in a good agreement with those obtained by ATR
FTIR spectroscopy. To our knowledge, this is the first
study dealing with the aspects of different fluoride
treatment applied to alumina/zirconia-sintered compos-
ites. Although it is known that fluoride is responsible
for the regulation of biomineralization process, the
chemical process that combines zirconia dental ceram-
ics with fluorine is still unexplained, as mentioned in
a very recently published report on dental ZrO2-based
materials.46
The most well-documented effect of fluo-
ride is that this ion substitutes for an hydroxyl in the
apatite structure, giving rise to a reduction in crystal
volume and, consequently, a more stable structure.47
Free fluoride ions in solutions can react with apatite
crystal or biomaterial in several different ways, depend-
ing on their concentrations and solution composition.
Of course, further in vitro tests are required to be per-
formed to establish a correlation between the effective-
ness of surface treatment in improving the bioactivity
of alumina/zirconia composites.
Conclusions
The composites investigated in this study are
designed for orthopedic and dental implants, being pre-
pared by Spark Plasma Sintering. The structural prop-
erties of alumina and alumina/zirconia composites were
determined by SEM analysis, X-ray diffraction, and
FTIR spectroscopy. As showed by SEM micrographs,
the grain growth of alumina particles was suppressed by
the addition of zirconia. No monoclinic phase of ZrO2
was detected from the XRD results, as supported also
by the FTIR spectra. The samples were fluorinated to
improve the performances of these bioceramics as con-
sidered for dental applications. The surface modifica-
tion of the specimens upon different treatments with
sodium tetrafluoroborate and stannous fluoride, respec-
tively, was investigated by ATR FTIR and XPS. Quali-
tative and quantitative results obtained by XPS and
ATR FTIR demonstrated that the proposed materials
are more sensitive to SnF2 than to NaBF4 treatment
8 International Journal of Applied Ceramic Technology—Cavalu, et al. 2013
9. for samples fluorination. These results support other
previously reported studies justifying the long-term
effectiveness of topical fluoride treatment in dentistry
and maxillofacial applications.
Acknowledgments
This work was supported by the Romanian
National Authority for Scientific Research CNCS-UE-
FISCDI, project PNII-ID-PCE 2011-3-0441 contract
237/2011 and Bilateral Cooperation between Romania
and Turkey 2012-2013.
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