This document discusses ceramics, including their classification, applications, and processing methods. It addresses how ceramics are classified into categories like glasses, clay products, refractories, and advanced ceramics. It also summarizes the main ceramic fabrication techniques of glass forming, particulate forming, and cementation. Key steps like drying, firing, and sintering are also outlined.
Ceramics are important engineering materials from engineering applications point of view.This presentation gives briefly important properties and applications of ceramics
This document discusses various types of crystal defects including point defects, line defects, and planar defects. It defines point defects as zero-dimensional defects involving a single atom change, such as vacancies, interstitials, and impurities. Line defects are described as one-dimensional dislocations, including edge and screw dislocations. Planar defects are two-dimensional grain boundaries that separate crystalline regions with different orientations within a polycrystalline solid. The document explores how these defects influence material properties.
Dispersion Hardening:
Hard particles:
Mixed with matrix powder
Consolidated
Processed by powder metallurgy techniques
Second phase – Very little solubility (Even at elevated temp.)
No coherency
So thermally Stable at very high temp.
Resists :
Grain growth
Over aging
Recrystallization
Mobility of dislocation
Different from particle Metallic Composites (Volume Fraction is 3 to 4% max.) (Does not affect stiffness)
Examples : Al2O3 in Al or Cu, ThO2 in Ni
1. Metals have the greatest number of dislocations present because dislocation motion is easiest in metals due to their non-directional bonding and close-packed crystal structures.
2. Strength and dislocation motion are related because dislocations allow plastic deformation via slip and strength increases as dislocation motion is impeded.
3. Heating alters strength and other properties by allowing recovery and recrystallization processes that reduce dislocation density and form new defect-free grains, decreasing strength but increasing ductility.
[1] Crystal defects are irregularities in the structure of a crystal that arise from imperfect packing of atoms. There are several types of crystal defects including point defects, line defects, surface defects, and volume defects.
[2] Point defects are zero-dimensional and include vacancies, interstitial defects, Schottky defects, and Frenkel defects. Line defects are one-dimensional and include edge and screw dislocations. Surface defects are two-dimensional and include grain boundaries, twin boundaries, and stacking faults. Volume defects are three-dimensional voids or non-crystalline regions within the crystal structure.
Composite materials are composed of two or more physically distinct phases that produce properties different from the individual components. Composites can be very strong yet light weight. Examples include fiberglass, carbon fiber reinforced plastics, and cemented carbides. Composites find applications in aerospace, automotive, sports equipment due to their high strength to weight ratio and other advantageous properties. They are classified based on matrix material (polymer, metal, ceramic) and type of reinforcement (particles, fibers).
This document discusses ceramics, including their classification, applications, and processing methods. It addresses how ceramics are classified into categories like glasses, clay products, refractories, and advanced ceramics. It also summarizes the main ceramic fabrication techniques of glass forming, particulate forming, and cementation. Key steps like drying, firing, and sintering are also outlined.
Ceramics are important engineering materials from engineering applications point of view.This presentation gives briefly important properties and applications of ceramics
This document discusses various types of crystal defects including point defects, line defects, and planar defects. It defines point defects as zero-dimensional defects involving a single atom change, such as vacancies, interstitials, and impurities. Line defects are described as one-dimensional dislocations, including edge and screw dislocations. Planar defects are two-dimensional grain boundaries that separate crystalline regions with different orientations within a polycrystalline solid. The document explores how these defects influence material properties.
Dispersion Hardening:
Hard particles:
Mixed with matrix powder
Consolidated
Processed by powder metallurgy techniques
Second phase – Very little solubility (Even at elevated temp.)
No coherency
So thermally Stable at very high temp.
Resists :
Grain growth
Over aging
Recrystallization
Mobility of dislocation
Different from particle Metallic Composites (Volume Fraction is 3 to 4% max.) (Does not affect stiffness)
Examples : Al2O3 in Al or Cu, ThO2 in Ni
1. Metals have the greatest number of dislocations present because dislocation motion is easiest in metals due to their non-directional bonding and close-packed crystal structures.
2. Strength and dislocation motion are related because dislocations allow plastic deformation via slip and strength increases as dislocation motion is impeded.
3. Heating alters strength and other properties by allowing recovery and recrystallization processes that reduce dislocation density and form new defect-free grains, decreasing strength but increasing ductility.
[1] Crystal defects are irregularities in the structure of a crystal that arise from imperfect packing of atoms. There are several types of crystal defects including point defects, line defects, surface defects, and volume defects.
[2] Point defects are zero-dimensional and include vacancies, interstitial defects, Schottky defects, and Frenkel defects. Line defects are one-dimensional and include edge and screw dislocations. Surface defects are two-dimensional and include grain boundaries, twin boundaries, and stacking faults. Volume defects are three-dimensional voids or non-crystalline regions within the crystal structure.
Composite materials are composed of two or more physically distinct phases that produce properties different from the individual components. Composites can be very strong yet light weight. Examples include fiberglass, carbon fiber reinforced plastics, and cemented carbides. Composites find applications in aerospace, automotive, sports equipment due to their high strength to weight ratio and other advantageous properties. They are classified based on matrix material (polymer, metal, ceramic) and type of reinforcement (particles, fibers).
The document discusses rate controlled sintering in advanced ceramic processes. It explains that sintering transforms ceramic powder compacts into dense materials through heating by reducing pores and growing grains. The driving force is lowering free energy. Sintering occurs in three stages and is affected by various factors. Rate controlled sintering controls the heating rate or temperature to control the sintering process for improved material properties. It provides examples demonstrating the effects of heating rate on microstructure.
(1) Crystal imperfections refer to defects in the regular geometric arrangement of atoms in a crystal structure. They influence properties like mechanical strength.
(2) Imperfections include point defects like vacancies and interstitial atoms, line defects like edge and screw dislocations, surface defects like grain boundaries, and volume defects like cracks and voids.
(3) Dislocations are one-dimensional defects where some atoms are misaligned. They are responsible for ductility in materials. Edge dislocations occur when a slip plane is incomplete, while screw dislocations involve a shear distortion.
OUTCOMES:
-Describes slips plane and slips direction
-Explain the types of dislocation.
-Understand the metallic crystal structure, FCC, BCC and HCP
-Understand the crystallographic direction and planes, and able to find the linear and planar density
-Explain about slip systems, the way to determine it and its effect on the metal characteritcs.
Ceramic materials are inorganic, non-metallic materials made from compounds of a metal and a non metal. Ceramic materials may be crystalline or partly crystalline.
The word ceramic comes from the Greek word keramiko of pottery" or for pottery from keramos.
The document presents information on crystal defects, specifically line defects. It discusses two types of line defects: edge defects and screw defects. Edge defects occur when an extra half-plane of atoms is introduced into the crystal structure. Screw defects occur when the planes of atoms trace a helical path around the dislocation line. The document was presented by Mehak Tariq, a student at Ghazi University DG Khan, as part of a class project on crystal defects.
This document provides information on the properties of ceramics. It begins with an introduction to ceramics, including their atomic bonding and crystal structures. It then discusses defects in ceramics and general properties such as brittleness, toughness, and strength at high temperatures. The document classifies ceramics and discusses various types including electronic ceramics. It provides details on properties like piezoelectricity and applications of piezoelectric ceramics in devices. Processing methods for ceramics are also briefly mentioned.
Ceramic Structures and properties: - coordination number and radius rations - AX,
AmXp, AmBmXp type crystal structures – imperfections in ceramics- phase diagrams of
Al2O3 – Cr2O3 and MgO- Al2O3 only – mechanical properties – mechanisms of plastic
deformation – ceramic application in heat engine, ceramic armor and electronic
packaging.
Phase refers to any physically distinct structure within a material. There are several types of phases including solid, liquid, and gas for pure elements. Alloys can also have multiple solid phases that differ in crystal structure. When other elements are added to a pure material intentionally as alloying elements, they are accommodated through solid solution, compound formation, or phase separation into distinct structures. Solid solutions are classified as substitutional, where atoms replace ones in the host lattice, or interstitial, where small atoms fill spaces within the host lattice. Compounds form new crystal structures distinct from the components. Hume-Rothery rules outline factors that influence solid solution formation such as atomic size, valence, and electronegativity differences between
This document discusses the classification of composite materials. Composites can be classified based on the type of matrix, such as polymer matrix composites, metal matrix composites, and ceramic matrix composites. They can also be classified based on the type of reinforcement, such as fibre reinforced composites, particulate composites, and laminates. The document provides details on different types of matrices, reinforcements, and examples of various composite materials.
In this presentation, a brief description of Young's Modulus, Hardness and Fracture Toughness is discussed, also an experimental way to determine the above mentioned properties is also discussed.
The document summarizes the presentation given by Vamsi Krishna Rentala on stress fields around dislocations. It first defines dislocations and the three main types: edge, screw, and mixed. It then describes how stress fields are produced by dislocations using linear elasticity theory. Simple models are used to illustrate the stress fields around screw and edge dislocations. Key results presented include the diverging stresses near dislocations and variations in stress type (tensile vs. compressive) above and below the slip plane for an edge dislocation. The document concludes by noting mixed dislocations contain both edge and screw components and summarizing some properties of stress fields.
This document discusses the thermo-mechanical processing of titanium alloys. It begins with an abstract describing titanium alloy properties and applications in aerospace and medical fields. It then covers titanium crystal structures, properties, advantages, classifications including commercially pure, alpha, near-alpha, alpha-beta and beta alloys. Heat treatments including annealing, quenching and aging are described for different alloy types. Microstructures, properties and applications of various alloys are also summarized.
This document discusses fracture mechanics and provides background information on the topic. It introduces key concepts in fracture mechanics including stress intensity factor, linear elastic fracture mechanics (LEFM), ductile to brittle transition, and fracture toughness. Applications of fracture mechanics are described such as its use in analyzing cracking in pavement systems. The document also covers probabilistic fracture of brittle materials and how their strength is affected by the presence of flaws.
Titanium is named after the Titans, the
powerful sons of the earth in Greek mythology.
• Titanium is the forth abundant metal on
earth crust (~ 0.86%) after aluminium, iron and
magnesium.
Titans
homepage.mac.com
Rutile (TiO2)
mineral.galleries.com
Ilmenite (FeTiO3)
• Not found in its free, pure metal form in
nature but as oxides, i.e., ilmenite (FeTiO3)
and rutile (TiO2).
• Found only in small amount in Thailand...
This document discusses the processing of traditional and new ceramics. It describes the key steps in ceramic processing which include preparation of raw materials, shaping, drying/dewatering, and firing/sintering. For traditional ceramics, the raw materials are naturally occurring minerals that are comminuted into powder and shaped using methods like slip casting or plastic forming before being dried and fired. New ceramics use synthetic powders and advanced shaping methods like dry pressing, hot pressing, or isostatic pressing, followed by sintering to achieve final densification. Sintering is a critical heat treatment process that bonds ceramic particles without melting by facilitating mass transfer through diffusion.
This document summarizes a seminar on cast metal matrix composites presented by Vijit Gajbhiye. It discusses various processing techniques for metal matrix composites including stir casting, sand and permanent mold casting, centrifugal casting, compocasting, infiltration, squeeze casting, vacuum infiltration, electromagnetic infiltration, and centrifugal infiltration. It provides examples of applications of metal matrix composites in automotive and aerospace industries such as pistons, brake rotors, and aircraft components.
Ceramic materials are inorganic, non-metallic materials made from compounds of metals and non-metals. Ceramic properties are determined by the atoms present and bonding between them. Ceramics are widely used in construction materials like bricks and tiles as well as industrial applications due to properties like corrosion and heat resistance. Common ceramic materials include alumina and silicon nitride, and ceramics are used in products like dental implants, gas turbine engines, and cutting tools.
Graphite is a natural form of carbon that occurs in metamorphic rocks. It is an excellent conductor of heat and electricity. While China produces 80% of the world's natural graphite, demand is growing due to applications in lithium-ion batteries, fuel cells, and other technologies. This creates supply risks as China also controls much of the exports. Turkey has many graphite occurrences, mainly of the amorphous type, but also contains deposits that are more crystalline and pure. Production in Turkey was over 18,000 tonnes in 1990 but has declined since, though demand remains high. Low-cost graphite projects and further development in Turkey may help address future supply needs.
The document discusses silicon carbide (SiC) as a material for high temperature power applications. SiC has several advantages over silicon, including higher thermal stability, lower intrinsic carrier concentration, and lower leakage current at high temperatures. These advantages allow SiC devices to operate at higher junction temperatures compared to silicon. The document outlines the crystal structure of SiC, its material properties, and why it can operate at higher temperatures. Commercial SiC devices are currently available as Schottky diodes up to 1200V. SiC has potential to improve power converter efficiency and allow for smaller components in high temperature applications like electric vehicles.
- Edward G Acheson produced silicon carbide in 1891 while experimenting to create a hard material by passing an electric current through a mixture of clay and coke. He recognized its abrasive properties, patented it, and formed The Carborundum Company.
- Silicon carbide is produced in furnaces and has properties of hardness, heat resistance, electrical conductivity, and strength at high temperatures. It can be used to replace ferroalloys in iron and steel production.
- Using silicon carbide provides benefits over ferroalloys like more efficient graphite formation, lower impurities, and reduced production costs.
The document discusses rate controlled sintering in advanced ceramic processes. It explains that sintering transforms ceramic powder compacts into dense materials through heating by reducing pores and growing grains. The driving force is lowering free energy. Sintering occurs in three stages and is affected by various factors. Rate controlled sintering controls the heating rate or temperature to control the sintering process for improved material properties. It provides examples demonstrating the effects of heating rate on microstructure.
(1) Crystal imperfections refer to defects in the regular geometric arrangement of atoms in a crystal structure. They influence properties like mechanical strength.
(2) Imperfections include point defects like vacancies and interstitial atoms, line defects like edge and screw dislocations, surface defects like grain boundaries, and volume defects like cracks and voids.
(3) Dislocations are one-dimensional defects where some atoms are misaligned. They are responsible for ductility in materials. Edge dislocations occur when a slip plane is incomplete, while screw dislocations involve a shear distortion.
OUTCOMES:
-Describes slips plane and slips direction
-Explain the types of dislocation.
-Understand the metallic crystal structure, FCC, BCC and HCP
-Understand the crystallographic direction and planes, and able to find the linear and planar density
-Explain about slip systems, the way to determine it and its effect on the metal characteritcs.
Ceramic materials are inorganic, non-metallic materials made from compounds of a metal and a non metal. Ceramic materials may be crystalline or partly crystalline.
The word ceramic comes from the Greek word keramiko of pottery" or for pottery from keramos.
The document presents information on crystal defects, specifically line defects. It discusses two types of line defects: edge defects and screw defects. Edge defects occur when an extra half-plane of atoms is introduced into the crystal structure. Screw defects occur when the planes of atoms trace a helical path around the dislocation line. The document was presented by Mehak Tariq, a student at Ghazi University DG Khan, as part of a class project on crystal defects.
This document provides information on the properties of ceramics. It begins with an introduction to ceramics, including their atomic bonding and crystal structures. It then discusses defects in ceramics and general properties such as brittleness, toughness, and strength at high temperatures. The document classifies ceramics and discusses various types including electronic ceramics. It provides details on properties like piezoelectricity and applications of piezoelectric ceramics in devices. Processing methods for ceramics are also briefly mentioned.
Ceramic Structures and properties: - coordination number and radius rations - AX,
AmXp, AmBmXp type crystal structures – imperfections in ceramics- phase diagrams of
Al2O3 – Cr2O3 and MgO- Al2O3 only – mechanical properties – mechanisms of plastic
deformation – ceramic application in heat engine, ceramic armor and electronic
packaging.
Phase refers to any physically distinct structure within a material. There are several types of phases including solid, liquid, and gas for pure elements. Alloys can also have multiple solid phases that differ in crystal structure. When other elements are added to a pure material intentionally as alloying elements, they are accommodated through solid solution, compound formation, or phase separation into distinct structures. Solid solutions are classified as substitutional, where atoms replace ones in the host lattice, or interstitial, where small atoms fill spaces within the host lattice. Compounds form new crystal structures distinct from the components. Hume-Rothery rules outline factors that influence solid solution formation such as atomic size, valence, and electronegativity differences between
This document discusses the classification of composite materials. Composites can be classified based on the type of matrix, such as polymer matrix composites, metal matrix composites, and ceramic matrix composites. They can also be classified based on the type of reinforcement, such as fibre reinforced composites, particulate composites, and laminates. The document provides details on different types of matrices, reinforcements, and examples of various composite materials.
In this presentation, a brief description of Young's Modulus, Hardness and Fracture Toughness is discussed, also an experimental way to determine the above mentioned properties is also discussed.
The document summarizes the presentation given by Vamsi Krishna Rentala on stress fields around dislocations. It first defines dislocations and the three main types: edge, screw, and mixed. It then describes how stress fields are produced by dislocations using linear elasticity theory. Simple models are used to illustrate the stress fields around screw and edge dislocations. Key results presented include the diverging stresses near dislocations and variations in stress type (tensile vs. compressive) above and below the slip plane for an edge dislocation. The document concludes by noting mixed dislocations contain both edge and screw components and summarizing some properties of stress fields.
This document discusses the thermo-mechanical processing of titanium alloys. It begins with an abstract describing titanium alloy properties and applications in aerospace and medical fields. It then covers titanium crystal structures, properties, advantages, classifications including commercially pure, alpha, near-alpha, alpha-beta and beta alloys. Heat treatments including annealing, quenching and aging are described for different alloy types. Microstructures, properties and applications of various alloys are also summarized.
This document discusses fracture mechanics and provides background information on the topic. It introduces key concepts in fracture mechanics including stress intensity factor, linear elastic fracture mechanics (LEFM), ductile to brittle transition, and fracture toughness. Applications of fracture mechanics are described such as its use in analyzing cracking in pavement systems. The document also covers probabilistic fracture of brittle materials and how their strength is affected by the presence of flaws.
Titanium is named after the Titans, the
powerful sons of the earth in Greek mythology.
• Titanium is the forth abundant metal on
earth crust (~ 0.86%) after aluminium, iron and
magnesium.
Titans
homepage.mac.com
Rutile (TiO2)
mineral.galleries.com
Ilmenite (FeTiO3)
• Not found in its free, pure metal form in
nature but as oxides, i.e., ilmenite (FeTiO3)
and rutile (TiO2).
• Found only in small amount in Thailand...
This document discusses the processing of traditional and new ceramics. It describes the key steps in ceramic processing which include preparation of raw materials, shaping, drying/dewatering, and firing/sintering. For traditional ceramics, the raw materials are naturally occurring minerals that are comminuted into powder and shaped using methods like slip casting or plastic forming before being dried and fired. New ceramics use synthetic powders and advanced shaping methods like dry pressing, hot pressing, or isostatic pressing, followed by sintering to achieve final densification. Sintering is a critical heat treatment process that bonds ceramic particles without melting by facilitating mass transfer through diffusion.
This document summarizes a seminar on cast metal matrix composites presented by Vijit Gajbhiye. It discusses various processing techniques for metal matrix composites including stir casting, sand and permanent mold casting, centrifugal casting, compocasting, infiltration, squeeze casting, vacuum infiltration, electromagnetic infiltration, and centrifugal infiltration. It provides examples of applications of metal matrix composites in automotive and aerospace industries such as pistons, brake rotors, and aircraft components.
Ceramic materials are inorganic, non-metallic materials made from compounds of metals and non-metals. Ceramic properties are determined by the atoms present and bonding between them. Ceramics are widely used in construction materials like bricks and tiles as well as industrial applications due to properties like corrosion and heat resistance. Common ceramic materials include alumina and silicon nitride, and ceramics are used in products like dental implants, gas turbine engines, and cutting tools.
Graphite is a natural form of carbon that occurs in metamorphic rocks. It is an excellent conductor of heat and electricity. While China produces 80% of the world's natural graphite, demand is growing due to applications in lithium-ion batteries, fuel cells, and other technologies. This creates supply risks as China also controls much of the exports. Turkey has many graphite occurrences, mainly of the amorphous type, but also contains deposits that are more crystalline and pure. Production in Turkey was over 18,000 tonnes in 1990 but has declined since, though demand remains high. Low-cost graphite projects and further development in Turkey may help address future supply needs.
The document discusses silicon carbide (SiC) as a material for high temperature power applications. SiC has several advantages over silicon, including higher thermal stability, lower intrinsic carrier concentration, and lower leakage current at high temperatures. These advantages allow SiC devices to operate at higher junction temperatures compared to silicon. The document outlines the crystal structure of SiC, its material properties, and why it can operate at higher temperatures. Commercial SiC devices are currently available as Schottky diodes up to 1200V. SiC has potential to improve power converter efficiency and allow for smaller components in high temperature applications like electric vehicles.
- Edward G Acheson produced silicon carbide in 1891 while experimenting to create a hard material by passing an electric current through a mixture of clay and coke. He recognized its abrasive properties, patented it, and formed The Carborundum Company.
- Silicon carbide is produced in furnaces and has properties of hardness, heat resistance, electrical conductivity, and strength at high temperatures. It can be used to replace ferroalloys in iron and steel production.
- Using silicon carbide provides benefits over ferroalloys like more efficient graphite formation, lower impurities, and reduced production costs.
GE has developed advanced silicon carbide (SiC) semiconductor technology that allows for more efficient and compact power electronics that can operate at higher voltages, temperatures, and frequencies compared to traditional silicon-based chips. GE has been researching SiC technology for over 50 years and has produced the first SiC power semiconductor that can operate at 200 degrees Celsius, which involves a fabrication process of almost 300 steps. SiC technology enables power electronics to be smaller and simpler while reducing power losses.
Silicon carbide (SiC) is a synthetic material that was first discovered in 1893. It is formed through heating carbon and silica in an Acheson graphite electric resistance furnace at temperatures between 1700-2500°C. The most common crystalline form is alpha-SiC. SiC has several desirable properties including high strength, hardness, thermal conductivity, and chemical inertness. Its applications include use in automotive parts, cutting tools, jewelry, and power electronics. Specifically, its wide bandgap and high operating temperature make it suitable for use in fast switching power devices such as Schottky diodes, MOSFETs, and IGBTs.
Nuclear damage parameters for SiC composites in fusion systemSURESH BHAISARE
The document discusses nuclear damage parameters for silicon carbide/silicon carbide (SiC/SiC) composites for use as structural materials in fusion reactor systems. It finds that:
1) The helium/dpa ratio is significantly higher in fusion reactors than fission reactors due to the harder neutron spectrum in fusion. This effect is more pronounced for SiC.
2) SiC/SiC composites are being considered for use in first walls, blankets, and other components due to their properties. However, lifetime is a major issue due to effects of radiation on the fiber, matrix, and interfaces.
3) Calculations were performed to determine dpa, helium production, hydrogen
China silicon carbide industry report, 2016 2020ResearchInChina
Since China's silicon carbide export quota was abolished, China’s silicon carbide export volume grew rapidly during 2013-2014, and tended to stabilize during 2015-2016. In 2016, China’s silicon carbide exports came to 321,500 tons, up 2.1% year on year; wherein, Ningxia’s export volume amounted to 111,900 tons, accounting for 34.9% of the total exports and acting as a main silicon carbide exporter in China.
As China's silicon carbide products are mainly low-end preliminarily processed products with moderate added value, the average price gap between export and import is enormous. In 2016, China's silicon carbide exports had the average price at USD0.9 / kg, less than 1/4 of the import average price (USD4.3 / kg).
SILICON-CARBIDE BASED TEMPERATURE SENSOR USING OPTICAL PYROMETRY AND LASER I...I'am Ajas
This document describes a silicon carbide based temperature sensor that uses optical pyrometry and laser interferometry to measure high temperatures. The sensor is able to reliably measure temperatures up to 2500°C, which makes it suitable for applications like gas turbine combustion chambers that require measuring temperatures of 1500°C. It works by using a tunable laser, beam splitter, and optical filters to direct thermal radiation from a silicon carbide target onto detectors. The detector output is related to temperature based on Planck's law and is calibrated by recording output ratios at different temperatures to create a calibration curve. Tests showed the sensor can measure temperature within 0.1°C resolution and is more accurate than thermocouples.
The document discusses silicon carbide, also known as SiC or carborundum. It is produced from quartz sand and petroleum coke in an electric resistant furnace at high temperatures. SiC has a hardness between corundum and synthetic diamond, and higher mechanical strength than corundum, making it suitable for abrasive tools. Green silicon carbide is produced using the same materials as black SiC but with the addition of salt. Green SiC has a hexagonal crystal structure, hardness, strong cutting ability, and excellent heat conductivity. It is purer than black SiC, making green SiC preferable for wire sawing applications unless the application requires lower cost over purity.
Silicon carbide is a compound of silicon and carbon with the chemical formula SiC. It occurs naturally as the rare mineral moissanite. Mass production of silicon carbide powder began in 1893 for use as an abrasive. Edward Acheson produced silicon carbide experimentally in 1891 and patented the process, founding the Carborundum Company. Silicon carbide exists in over 250 crystalline structures and polymorphs. It has excellent chemical and physical properties including high hardness, thermal conductivity, resistance to acids and heat. The main production method involves heating quartz sand and carbon in an electric resistance furnace above 2000°C. Silicon carbide has many applications due to its properties, including use in abrasives, automotive brake discs
Silicon carbide (SiC) is a wide bandgap semiconductor material with exceptional properties like high thermal conductivity, high electric field breakdown strength, and high saturated electron drift velocity. These properties make SiC useful for applications requiring high temperature, high power, and high frequency performance. SiC was first discovered in 1824 and was later synthesized as a bulk material in 1891. Common growth methods now include vapor-phase epitaxy. Over 200 SiC polytypes exist due to its polymorphic crystal structure, with the most common being 3C, 2H, 4H, and 6H SiC. Doping allows SiC to be made n-type or p-type for semiconductor devices. SiC's wide bandgap
This technical presentation summarizes ceramic composites. It begins by defining ceramics and composites. Ceramic composites have higher strength, damage tolerance, and toughness than monolithic ceramics due to reinforcement. Examples of structural ceramic composites in aerospace include rocket engine nozzles and scramjet engines. Case studies show ceramic composite armor provides ballistic impact protection while reducing weight compared to steel. Reinforcements like silicon carbide and matrices like alumina are discussed. In conclusion, ceramic composites are well-suited for applications requiring high-temperature or weight-constrained ballistic impact protection.
3 Things Every Sales Team Needs to Be Thinking About in 2017Drift
Thinking about your sales team's goals for 2017? Drift's VP of Sales shares 3 things you can do to improve conversion rates and drive more revenue.
Read the full story on the Drift blog here: http://blog.drift.com/sales-team-tips
How to Become a Thought Leader in Your NicheLeslie Samuel
Are bloggers thought leaders? Here are some tips on how you can become one. Provide great value, put awesome content out there on a regular basis, and help others.
This document discusses magnesium and its properties and production processes. Magnesium is the lightest structural metal and has good properties like strength, rigidity, and recyclability. It can be extracted through electrolytic processes or thermal reduction, then alloyed and given surface treatments. Common alloys produced include AZ91, AM60, and AM50 which are used in die casting applications. Magnesium has attractive characteristics for automotive and other applications to reduce weight and improve fuel efficiency.
IJERD (www.ijerd.com) International Journal of Engineering Research and Devel...IJERD Editor
This study investigated hydrogenated amorphous silicon (a-Si:H) and microcrystalline silicon (μc-Si) thin films deposited by inductively coupled plasma chemical vapor deposition (ICP-CVD) for potential use in hetero-junction (HJ) solar cells. Raman spectroscopy showed peaks indicating the presence of a-Si:H and μc-Si in deposited films. Films deposited at low temperature followed by solid phase crystallization exhibited a crystalline peak, demonstrating microcrystalline phase in an amorphous matrix. Different HJ solar cell structures were fabricated and tested, including structures with and without a μc-Si buffer layer.
The document summarizes research on inkjet-printed graphene for flexible micro-supercapacitors. Graphene is an ideal electrode material due to its high surface area, conductivity, and stability. The researchers used graphene oxide ink that was reduced to graphene after printing. Printed graphene films were highly porous with a surface area of 282 m2/g. Electrochemical testing showed the printed graphene achieved a capacitance of 132 F/g and could be charged and discharged rapidly while retaining 97% of its capacitance over many cycles. The research demonstrated inkjet printing as a scalable method for producing graphene-based flexible micro-supercapacitors.
Zinc Oxide Nanowires Prepared by Hot Tube Thermal EvaporationSyahida Suhaimi
The document describes a study investigating the effect of substrate tilt angle and argon gas flow rate on the structural properties of zinc oxide nanowires synthesized using a hot tube thermal evaporation method. Zinc oxide nanowires were grown on silicon substrates under different tilt angles (0-30 degrees) and flow rates (1.1-5.0 sccm). The nanowires were characterized using field emission scanning electron microscopy and energy dispersive X-ray spectroscopy. The results showed that higher tilt angles and flow rates produced nanowires with improved density, higher aspect ratio, and altered optical properties.
Isaf2007 Presentation Bst Ito Funakubo KoutsaroffIvo Koutsaroff
1. The document discusses the effect of strain from the substrate on the tunability of (100) one-axis oriented (Ba0.5Sr0.5)TiO3 thin films.
2. (Ba,Sr)TiO3 films were prepared on substrates with different thermal expansion coefficients to induce varying degrees of tensile and compressive strain. The dielectric properties of the films were then characterized.
3. The results showed that the relative dielectric constant and tunability of the films increased with compressive strain and decreased with tensile strain, consistent with expectations based on thermal strain calculations and previous literature.
Robust Welding Schedules Sheet Metal Welding ConferenceGajendra Tawade
The document presents the results of experimental spot welding trials to develop robust welding lobes for DP600 steel. Single pulse and enhanced double pulse welding schedules were tested to weld DP600 to itself and to HSLA steel. Analysis of the weld nugget growth showed that an enhanced double pulse with 87.5% current intensity on the second pulse produced wider welding lobes compared to a single pulse. Wider welding parameter windows allow for greater flexibility during vehicle assembly.
Novel applications of nano and multiscale composites through case studiesPadmanabhan Krishnan
This document discusses novel applications of nano-composites and multiscale composites through five case studies. It summarizes the nanostructuring of Kevlar fibers through surface chemical modification for better composite properties. It also discusses multiscale dental composites and novel nano-steel and nano cast iron containing carbon nano phases. Additionally, it outlines glass fabric/epoxy composites containing carbon nanotubes for electronic and structural applications. Finally, the synthesis of a bio-resin nano-composite containing nano-silica and carbon black for electronics is described.
The document presents research on estimating temperature distribution in silicon during micro laser assisted machining. Experiments were conducted using a diamond tipped tool attached to an infrared laser to preferentially heat and soften silicon. Thermal imaging showed the temperature increased through stages as the high pressure phase of silicon transformed. Analytical and finite element models were developed to estimate the temperature profile using properties of silicon phases. The models predicted temperature increases of 778°C and 468°C that agreed with experimental results. Future work could investigate other laser wavelengths and machining processes.
Material technology Newly develpoed engineering materialsMihir Taylor
This document discusses several newly developed engineering materials including lead zirconate titanate (PZT), zirconium dioxide (ZrO2), amorphous silicon, and magneto rheological fluid. PZT is a piezoelectric ceramic used in sensors and actuators due to its ability to generate voltage or change shape with electric fields or temperature changes. ZrO2 is a ceramic material that can be stabilized in different crystal phases for uses like thermal barriers or insulators. Amorphous silicon lacks a crystalline structure but can be used in devices like thin-film transistors and solar cells when hydrogenated. Magneto rheological fluid increases viscosity when exposed to magnetic fields, allowing controllable damp
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1. 1
FABRICATION OF SiC/SiCf COMPOSITE
BY VACUUM INFILTRATION AND
HOT PRESSING
Parlindungan Yonathan1, Jong-Hyun Lee1, Dang-Hyok Yoon1,
Weon-Ju Kim2 and Ji-Yeon Park2
1School of Materials Science and Engineering, Yeungnam University
2Nuclear Materials Research Division, KAERI, Korea
2. 2
Presentation Outline
Background
SiC/SiCff Experiment advantages
SiC/SiC applications and
Fusion reactors applications and issues
Conclusion
Main Goal
Materials
Process
Composition
Design
Result
4. 4
SiC/SiCf Advantages
High specific strength
Good high-temperature properties
Good fracture resistance
Good thermal conductivity
Corrosion and wear resistance
Low induced radioactivity under nuclear
environments
6. 6
Fusion Reactors
He bubbles
First Wall
Be, Be-alloy
W, W-alloy
SiC/SiCf,C/C
Fusion reactor blanket concept:
• TAURO, European Union (SiC/SiCf)
• ARIES-AT, US (SiC/SiCf)
• DREAM, Japan (Be-Li2O-SiC)
ARIES-AT vertical cross-section
*Fusion technology institute, University Wisconsin
7. Permeability issue in SiC/SiCf 7
0.86Å
Bombardment of high Point defect behavior in
energetic neutrons in to ceramics
composite surface
He and H atoms will move to a
Bubbles formation on the porous site, vacancy cluster,
surface or blistering and grain boundary to start
causing delamination issue
* J.H Kim, Y.D Kwon, Parlindungan Yonathan, I. Hidayat, “The energetic of He and H atoms in the irradiated β-SiC: ab
initio approach”
8. 8
Main Goal
To achieve a high density SiC/SiCf composite by
maximizing SiC slurry infiltration into SiC woven fiber
and finally to attain high structural strength composite
material
Process development high density composite material:
Milling process
Infiltration method
Slurry composition
Tape casting
Evaluation of material performance
Material characteristics and morphology
Mechanical properties
10. 10
SiC powder
β-SiC, NanoAmor β-SiC, Marketech
Average particle size: 52nm(NanoAmor),
30nm(Marketech)
Fine & spherical β-SiC
BET: 80 m2/g (NanoAmor), 109 m2/g (Marketech)
Surface is covered with SiO2 layer thinner than 1.7nm
2nm
11. 11
SiC Woven fiber
(220nm)
Top view Cross-section view Pyrolitic carbon-coated fiber
TyrannoTM-SA Grade-3 Fiber
Ube Industries, Ltd., Tokyo, Japan 2D woven fiber
Properties Tyranno-SA Grade-3
Atomic composition (C/Si) 1.08, Al 0.005
PyC coated by KAERI
Diameter (mm) 7.5 PyC coated design was
Number of
filaments/yarn
1600 based on CVI-SiC/SiCf
Tensile strength (MPa) 2500 composite process
Mass density (g/cm3) 3.1
12. 12
Sintering Additives
Alumina Oxide (Al2O3) Magnesium Oxide (MgO) Yttrium (III) Oxide (Y2O3)
Sintering additives facilitate the densification of
SiC due to its highly covalent bond structure
Al2O3/Y2O3/MgO = (0.64/0.26/0.1) wt%*
Liquid phase assisted sintering
* KY Lim, DH Jang, YW Kim, JY Park, DS Park,quot; Effect of the processing parameters on the densification and strength
of 2D SiC fiber-SiC matrix composites fabricated by slurry infiltration and stacking process
14. 14
Process focus
Milling (dispersion)
Solid volume fraction in green body
Infiltration
Rate of infiltration and densification
Sinterability (pressure, temperature)
Effective infiltration
Controllable infiltration
15. 15
Ball milling vs. High Energy
Milling
@
Ball mill High energy mill
The most conventional Recently introduced
mechanical milling (MiniCer, Netzsch)
2–200 mm spherical or 0.01 – 0.8 mm ZrO2 beads
cylindrical balls
Rotation up to 4200rpm
Rotation under 200 rpm
Very effective in milling
16. 16
Why HEM
Milling time (min) Herring’s scalling laws:
0 20 40 60 80 100 120
n
15000
t1 ⎛ r1 ⎞
High energy milling
=⎜ ⎟
⎜r ⎟
⎝ 2 ⎠
12000
t2
Viscosity(mPa.s)
9000 At constant temp
Ball milling Rumpf’s Equation:
6000
1.1φ A
3000 σ= .
0
1 − φ 12rl 2
0 20 40 60 80 100 120
Milling time (hr)
All proposed mechanisms of sintering and densification of ceramic powder
compacts agree that the particle size is one of the most important parameters
in the rate of progress of these processes.
* Nono Darsono a, Dang-Hyok Yoon a,*, Jaemyung Kim b, “Milling and dispersion of multi-walled
carbon nanotubes in texanol”
17. 17
Vacuum Infiltration
Enhance the infiltration by vacuum
absorption force
Enhance the composite density in
fiber
18. 18
Vacuum Infiltration
The slurry is infiltrated as the
vacuum pressure
Vacuum release
Vacuum on progressively released to
return to surrounding pressure,
thereby causing the slurry to
be forced through the fiber
pores.
Advantages:
SiC Slurry Using vacuum force to help
infiltration process
SiC Fiber Infiltration can be controlled by
altering the vacuum pressure
and release of vacuum time.
Vacuum pressure 0.1Pa
Pumping speed 120L/min
19. 19
Vacuum Infiltrated fiber - SEM
Top view
Cross-section view
Normal infiltration (dipping) Vacuum infiltration
28. 28
Composite structure
Composite formed by stacking
SiC green tape
the SiC green sheet and the
Infiltrated SiC infiltrated SiC fibers
fiber with SiC
slurry Binder burn-out at 4000C for 2-
hours at 1oC/min
Hot pressed at 1750oC, 20MPa,
Hot pressing 3-hours
5cm SiC infiltrated SiC infiltrated
fiber (NanoAmor) fiber
20 infiltrated fibers and (Marketech)
tapes
SiC/SiCf composite [0o/45o] Green tape Green tape
62-72% fiber volume fraction (NanoAmor) (Marketech)
29. 29
Effect of green tape
Binder solution
HEM (High energy milling)
vacuum infiltration & stack with SiC
Tapes
Drying Cryo-fracture
Binder burn-out SEM
Tape casting
Sintering (Hot Factors:
Pressing)
Slurry composition
Dispersion
Bending test Density SEM Zeta potential
(4-point) (Archimedes)
Viscosity
DISPERSION STABILITY AND ITS EFFECT ON TAPE CASTING OF SOLVENT-BASED SiC SLURRY
Jong-Hyun Lee, Parlindungan Yonathan, Dang-Hyok Yoon, Weon-Ju Kim* and Ji-Yeon Park* (Yeungnam University,
Korea, * KAERI, Daejeon, Korea)
30. Sintered SiC/SiCf 30
Relative density & Flexural strength of SiC/SiC f
100 300
Flexural Strength (MPa)
Relative Density (%)
200
80 Sample 1 (Nano-tape)
100
60
Nano-tape Nano Marketech
Powder type Sample 2 (Nano)
Vacuum
Other Hot
infiltration &
pressing CVI-PiP
Hot pressing
reported value
Density (g/cm3) 3.161 2.9-3.0 2.5-2.8
Percent density (%) 98.78% 90-95% 80-90%
Sample 3 (Mark-tape)
33. 33
XRD result
XRD result of SiC/SiC f composite The phase
structure were
Marketech
Sample 3 changed for
both nano
powder,
Intensity (a.u.)
Nano however phase
Sample 2 change were
not observed
for marketech
β− SiC phase Nanotape powder
α− SiC phase Sample 1
20 30 40 50 60 70 80
2θ
34. 34
Conclusion
• High density of SiC/SiCf was achieved at 3.161g/cm3
(98.78%) by vacuum infiltration and hot pressing process.
• Flexural strength of 230MPa was achieved with a brittle
fracture mode showing very little fiber pull out.
• Phase changed was observed after hot pressing at 1750oC-
20MPa-3hours, showing both alpha and beta-SiC phase in
the composite.
• SiC tape improved the sintered density and strength in the
SiC/SiCf composite.
• Slurry formulation including sintering additives plays an
important role in vacuum infiltration and hot pressing process.
• More intensive experiment on SiC/SiCf interface to improve
the composite strength.
35. 35
Acknowledgement
This project is financial supports by:
The Ministry of Knowledge Economy through a Materials &
Components Technology R&D Program
Highly appreciated