Mark D. Ediger (University of Wisconsin-Madison) presents at the Fred Kavli Special Symposium: From Unit Cell to Biological Cell at the APS March Meeting 2019 in Boston, MA. View abstract below.
-------------------------------------------------
The Design And Growth Of Ultra-Stable Glasses
-------------------------------------------------
Glasses are generally regarded as highly disordered and the idea of "controlling" molecular packing in glasses is reasonably met with skepticism. However, as glasses are non-equilibrium materials, a vast array of amorphous structures are possible in principle. Physical vapor deposition (PVD) allows a surprising amount of control over molecular packing in glasses and can be used to test the limits of amorphous packing in two ways. PVD can prepare glasses that approach the limits of the most dense and lowest energy amorphous packings that are possible. The activation barriers for rearrangements in these materials are very high, giving rise to high thermal and chemical stability. In addition, PVD allows control over anisotropic packing in glasses. For rod-shaped molecules, for example, glasses can be prepared in which the molecules have a substantial tendency to stand-up or lie-down relative to the substrate. As these materials have applications in organic electronics, an important question is: How much anisotropic order can be added to a glass without destroying key technological advantages such as macroscopic homogeneity? The high density and anisotropic packing of PVD glasses can be explained by a mechanism that is "anti-epitaxial" as structure is templated by the top surface rather than by the underlying substrate.
Synthesis and charaterization of la1 x srxmno3 perovskite nanoparticlesMai Trần
In recent times perovskite materials are extensively studied and have attracted much attention because they exhibit interesting the properties, showing potential applications in commercial, technical and biomedical. In Vietnam, perovskite materials be of interest research and applications are strong but with major research direction is to go deep into the electrical properties and the magnetic properties. The Lanthanum Strontium manganite is a perovskite-based crystal-structured ceramic material with the formula of La1-xSrxMnO3, where x describes the doping ratio. It has attracted much attention due to its good magnetic, electrical, and catalytic properties and is becoming an attractive possibility material in several biomedical applications, particularly with nano-size. In industry, this material is commonly used in as a cathode material in commercially produced solid oxide fuel cells. In this thesis, we present the Perovskite nanoparticles La1-xSrxMnO3 were successfully synthesized of the nanosize La1-xSrxMnO3 at x = 0; 0.1; 0.2; 0.3 and 0.4 which prepared by a modified sol-gel method. Structure and magnetic properties of them were systematically investigated in dependence on doped Sr ratio x. The structure was investigated by XRD and show slightly changed but magnetic properties varied strongly with changing the doping ratio x. Magnetic properties of samples were studied by Vibrating Sample Mode of Physical Properties Measurement System show at the room temperature, the samples show superparamagnetic properties with high saturated magnetization MS of 57 emu/g which strongly dependents on the doped Sr ratio x.
A dental implant (also known as an endosseous implant or fixture) is a surgical component that interfaces with the bone of the jaw or skull to support a dental prosthesis such as a crown, bridge, denture, facial prosthesis or to act as an orthodontic anchor. The basis for modern dental implants is a biologic process called osseointegration where materials, such as titanium, form an intimate bond to bone.
We are going to discuss the four Biomaterials and their Dental Applications, the Advantages and Disadvantages of each Material.
Plenary lecture of the XIV SBPMat Meeting, given by Prof. Paul Ducheyne (University of Pennsylvania, USA) on September 29, 2015, in Rio de Janeiro (Brazil).
Mark D. Ediger (University of Wisconsin-Madison) presents at the Fred Kavli Special Symposium: From Unit Cell to Biological Cell at the APS March Meeting 2019 in Boston, MA. View abstract below.
-------------------------------------------------
The Design And Growth Of Ultra-Stable Glasses
-------------------------------------------------
Glasses are generally regarded as highly disordered and the idea of "controlling" molecular packing in glasses is reasonably met with skepticism. However, as glasses are non-equilibrium materials, a vast array of amorphous structures are possible in principle. Physical vapor deposition (PVD) allows a surprising amount of control over molecular packing in glasses and can be used to test the limits of amorphous packing in two ways. PVD can prepare glasses that approach the limits of the most dense and lowest energy amorphous packings that are possible. The activation barriers for rearrangements in these materials are very high, giving rise to high thermal and chemical stability. In addition, PVD allows control over anisotropic packing in glasses. For rod-shaped molecules, for example, glasses can be prepared in which the molecules have a substantial tendency to stand-up or lie-down relative to the substrate. As these materials have applications in organic electronics, an important question is: How much anisotropic order can be added to a glass without destroying key technological advantages such as macroscopic homogeneity? The high density and anisotropic packing of PVD glasses can be explained by a mechanism that is "anti-epitaxial" as structure is templated by the top surface rather than by the underlying substrate.
Synthesis and charaterization of la1 x srxmno3 perovskite nanoparticlesMai Trần
In recent times perovskite materials are extensively studied and have attracted much attention because they exhibit interesting the properties, showing potential applications in commercial, technical and biomedical. In Vietnam, perovskite materials be of interest research and applications are strong but with major research direction is to go deep into the electrical properties and the magnetic properties. The Lanthanum Strontium manganite is a perovskite-based crystal-structured ceramic material with the formula of La1-xSrxMnO3, where x describes the doping ratio. It has attracted much attention due to its good magnetic, electrical, and catalytic properties and is becoming an attractive possibility material in several biomedical applications, particularly with nano-size. In industry, this material is commonly used in as a cathode material in commercially produced solid oxide fuel cells. In this thesis, we present the Perovskite nanoparticles La1-xSrxMnO3 were successfully synthesized of the nanosize La1-xSrxMnO3 at x = 0; 0.1; 0.2; 0.3 and 0.4 which prepared by a modified sol-gel method. Structure and magnetic properties of them were systematically investigated in dependence on doped Sr ratio x. The structure was investigated by XRD and show slightly changed but magnetic properties varied strongly with changing the doping ratio x. Magnetic properties of samples were studied by Vibrating Sample Mode of Physical Properties Measurement System show at the room temperature, the samples show superparamagnetic properties with high saturated magnetization MS of 57 emu/g which strongly dependents on the doped Sr ratio x.
A dental implant (also known as an endosseous implant or fixture) is a surgical component that interfaces with the bone of the jaw or skull to support a dental prosthesis such as a crown, bridge, denture, facial prosthesis or to act as an orthodontic anchor. The basis for modern dental implants is a biologic process called osseointegration where materials, such as titanium, form an intimate bond to bone.
We are going to discuss the four Biomaterials and their Dental Applications, the Advantages and Disadvantages of each Material.
Plenary lecture of the XIV SBPMat Meeting, given by Prof. Paul Ducheyne (University of Pennsylvania, USA) on September 29, 2015, in Rio de Janeiro (Brazil).
Implant dentistry is growing well in Myanmar. As a faculty member and a dentist who is specialized in Prosthetic Dentistry including Dental Implant, the presenter notice that we have to move another one step...usage of bio-material... in clinical practice.
K2O - CdO - B2O3 – SiO2glasses containing different concentrations of MnO2 have been prepared. The Physical properties of the glasses are studied from their density. The studies have been analysed in the light of different oxidation states of manganese ion with the aid of the data from optical absorption. The analysis shows that manganese ions exist mainly in Mn2+ state, occupy tetrahedral positions and increase the insulating strength of the glass if MnO2 is present in smaller concentrations.
Synthesis and Elastic Studies of Lead Boro-Tellurite Glass SystemSidek Aziz
Synthesis and Elastic Studies of Lead Boro-Tellurite Glass System presented Seminar Kebangsaan Aplikasi Sains dan Matematik 29-30 October 2013 ata UTHM Johor
Growth and Optimization of Aluminium-doped Zinc Oxide using Spray Pyrolysis T...Kevin V. Alex
Highly conducting and transparent Al-doped ZnO thin films were grown on glass substrate using 0.3M of zinc acetate dihydrate and aluminum acetylacetonate solution via spray pyrolysis technique. Methanol was used as the main solvent and Nitrogen as the carrier gas. This work consists of two set of studies. The structural properties of the grown films were characterized using XRD. The crystallite size was also calculated from the XRD data. The optical studies of the prepared samples were studied using UV-Vis spectrometer and their respective optical band-gaps were determined. The film thickness was measured using the stylus profiler while the resistivity measurements were done in the source measuring unit. The surface morphology of the film was studied using the SEM images of the samples.
Embedding is the process in which the tissues or the specimens are enclosed in a mass of the embedding medium using different types of mould e.g steel molds ,glass
mold, plastic molds etc . Embedding is the crucial step in determining the orientation of sectioning. the tissue blocks are very thin in thickness they need a supporting
medium in which the tissue blocks are embedded. This supporting medium is called embedding medium. Various embedding substances are paraffin wax, celloidin,
synthetic resins, gelatine, etc.
Implant dentistry is growing well in Myanmar. As a faculty member and a dentist who is specialized in Prosthetic Dentistry including Dental Implant, the presenter notice that we have to move another one step...usage of bio-material... in clinical practice.
K2O - CdO - B2O3 – SiO2glasses containing different concentrations of MnO2 have been prepared. The Physical properties of the glasses are studied from their density. The studies have been analysed in the light of different oxidation states of manganese ion with the aid of the data from optical absorption. The analysis shows that manganese ions exist mainly in Mn2+ state, occupy tetrahedral positions and increase the insulating strength of the glass if MnO2 is present in smaller concentrations.
Synthesis and Elastic Studies of Lead Boro-Tellurite Glass SystemSidek Aziz
Synthesis and Elastic Studies of Lead Boro-Tellurite Glass System presented Seminar Kebangsaan Aplikasi Sains dan Matematik 29-30 October 2013 ata UTHM Johor
Growth and Optimization of Aluminium-doped Zinc Oxide using Spray Pyrolysis T...Kevin V. Alex
Highly conducting and transparent Al-doped ZnO thin films were grown on glass substrate using 0.3M of zinc acetate dihydrate and aluminum acetylacetonate solution via spray pyrolysis technique. Methanol was used as the main solvent and Nitrogen as the carrier gas. This work consists of two set of studies. The structural properties of the grown films were characterized using XRD. The crystallite size was also calculated from the XRD data. The optical studies of the prepared samples were studied using UV-Vis spectrometer and their respective optical band-gaps were determined. The film thickness was measured using the stylus profiler while the resistivity measurements were done in the source measuring unit. The surface morphology of the film was studied using the SEM images of the samples.
Embedding is the process in which the tissues or the specimens are enclosed in a mass of the embedding medium using different types of mould e.g steel molds ,glass
mold, plastic molds etc . Embedding is the crucial step in determining the orientation of sectioning. the tissue blocks are very thin in thickness they need a supporting
medium in which the tissue blocks are embedded. This supporting medium is called embedding medium. Various embedding substances are paraffin wax, celloidin,
synthetic resins, gelatine, etc.
The discovery and commercialization of graphene, the first two-dimensional material, which is impossibly thin and incredibly strong, has kicked off a renaissance in nanomaterial research and development. This revolution in the understanding of manipulation at the molecular level could reshape a range of businesses, including energy, construction, and manufacturing. Thus far, however, the large incumbent chemical companies have remained aloof from the hive of activity at startups and in academic research labs. Given the potential of these materials to alter a host of industries, that aloofness may be a luxury they can no longer afford.
this presentation was prepared for the first annual Cal Poly Materials Engineering Industry Day, with the intention of inspiring Materials Engineering students about the wide variety of careers and opportunities available to them as Materials Engineers.
Did you know that a surfboard could be made out of mushrooms? That NASA has developed a self-healing material and that most of the contents in an oil barrel is burned rather than being used as raw material? Check out our infographic on new materials.
Nanotechnology: Shaping the world atom by atomIJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
Portal Projects examines the components of Digital and Ark Glass and looks for its relevancy to known projects and methods that support the technology. It also recommends a profile for starting resources of glass business and steps through the growth of its business case startup Magi and Marcus, ENG through their streamline, remote and branching efforts. V1 is an examination of Portal Evidence for building upon the topic.
The beauty and nightmare of plastics, bath university 2019Malcolm Mackley
This presentation was given at Bath University in March 2019 and it describes the beauty of science relating to plastics and the problems associated with certain application areas of the material
2016-June-15-Glass - An unsung hero of scientific revolution
1. Ashutosh Goel
Department of Materials Science and Engineering
Rutgers, The State University of New Jersey
Glass – An unsung hero of the scientific
revolution
2. Picture, if you can, a world without glass. There would be no microscopes or
telescopes, no sciences of microbiology or astronomy. People with poor vision would
grope in the shadows, and planes, cars won’t exist. Artists would draw without the
benefit of three-dimensional perspective, and ships would still be steered by what stars
navigators could see through the naked eye.
A. Macfarlane and G. Martin, “Glass: A World History”, The University of Chicago Press, 2002
Grumpy cat with Google Glass
A world without glass
4. What is glass?
Classical definition: “Glass is a super-cooled liquid.”
If this statement is “true”, does glass flow over time?
Are medieval windows melting/flowing?
Italian stained-glass windows, from medieval
times, are often round - like this one from the
Basilica di Santa Maria del Fiore in Florence.
Courtesy: www.awesomestories.com
In medieval European cathedrals, the glass sometimes
looks odd. Some panes are thicker at the bottom than
they are at the top. The seemingly solid glass appears
to have melted. This is evidence, say tour guides,
internet rumors and even high school chemistry
teachers, that glass is actually a liquid. And, because
glass is hard, it must be a supercooled liquid.
- C. Curtin, “Fact or Fiction?: Glass is a (supercooled) liquid”,
Scientific American, Feb 22, 2007.
5. What is glass?
According to a study conducted by Professor Edgar D. Zanotto, window glasses may flow at
ambient temperature only over incredibly long times, which exceed the limits of human
history.
- E.D. Zanotto, “Do cathedral glasses flow?”, American Journal of Physics, 66 (1998) 392.
Glass is actually neither a liquid – supercooled or otherwise – nor a solid. It is an amorphous
solid – a state somewhere between those two states of matter. And yet, glass’s liquid-like
properties are not enough to explain the thicker-bottomed windows, because glass atoms move
too slowly for changes to be visible.
- C. Curtin, “Fact or Fiction?: Glass is a (supercooled) liquid”, Scientific American, Feb 22, 2007.
Can we still define glass to be a supercooled liquid?
If medieval windows are not flowing, why the bottom part of these
windows is thicker than the remaining window?
6. If medieval windows are not flowing, why the bottom part of
these windows is thicker than the remaining window?
Crown glass manufacture, C18th
Courtesy: Corning Museum of Glass
The reason behind non-uniform thickness of medieval windows may be attributed to their manufacturing
process. At that time, glassblowers created glass cylinders that were then flattened to make panes of glass.
The resulting pieces may never have been uniformly flat and workers installing windows preferred, for
one reason or another, to put the thicker sides of the pane at the bottom. This gives them a melted look,
but does not mean glass is true liquid.
- C. Curtin, “Fact or Fiction?: Glass is a (supercooled) liquid”, Scientific American, Feb 22, 2007.
14. First compound microscope
A clinical mercury-in-glass
thermometer
Glass Lab ware
Microscope: One of the first major developments
leading to saving of lives was the optical microscope
(Year: 1590). The invention of the microscope using
glass spheres to focus on the objects was the seminal
step towards discovering microscopic life, for example:
pathogens. This discovery led to the treatment and
eventually elimination of many diseases.
Other examples: Thermometers, Lab ware, Eye glasses
This enormous social change can be termed a revolution in life
preservation.
A major consequence of life preservation was an expansion of
the human lifespan from an average of 45 years to 78 years.
It is projected that by 2050, there will be more than 1 billion
people alive on earth aged 60 years or older.
Hench et al., Glass and Medicine, Int. J. Appl. Glass Sci. 1(2010) 104-117
15. The second revolution in healthcare has occurred in last 50 years, i.e. a
revolution in tissue replacement.
Bio-inert Biomaterials
CellProteins
Bioactive Biomaterials
Cell
Adhesion,
spreading,
migration, growth,
apoptosis and
differentiation
Human “spare parts” is a huge business worth tens of billions of dollars
http://www.synergybiomedical.com/technology.htm
16. 45S5 Bioglass®
(mol.%): 46.1 SiO2 - 26.9 CaO - 24.4 Na2O - 2.5 P2O5
First bioactive materials were
discovered by Hench et al. in 1971.
They designed melt-derived Na2O-CaO-P2O5-SiO2 based glasses which have the ability to
bond to bone and soft tissues in human body through a sequence of chemical processes.
The most bioactive composition discovered until today from this class of materials is
45S5 Bioglass®, which has been used in > 650,000 human cases already.
J. Am. Ceram. Soc. 74 (1991) 1487
17.
18. Scaffold fabrication from bioactive glass
Trinity of an ideal biomaterial for
tissue engineering and
regenerative medicine
- Underlying concept of tissue engineering is the belief that cells can be
isolated from the patient, and its population then can be expanded in a
cell culture and seeded onto a carrier. The resulting tissue engineering
construct is then grafted back into the same patient to function as the
introduced replacement tissue.
- This new paradigm requires scaffolds that balance temporary
mechanical function with mass transport to aid biological delivery and
tissue regeneration in three dimensions (3D).
- The choice of a suitable material for fabrication of scaffold with
desired properties is the biggest challenge.
Desired properties
Right surface chemistry to promote cell
attachment
Biodegradability – degradable into non-
toxic components
Mechanical strength – needed for
creation of macroporous scaffold that
will retain the structure after
implantation
21. Our research in the field of bioactive glasses
2 Merino sheep
(Age: 1 year)
We created 5 non-critical
defects with 5 mm
diameter in lateral
diaphysis in the femur
1st defect: Empty (control)
2nd defect: 45S5 (Reference)
3rd – 5th defect: FastOsTM
Defects in femur diaphysis
3 mm
45S5
3 mm
Control
FastOs
3 mm
23. Nuclear waste management in USA
Hanford site - 586 mi.2 of desert next
to Columbia river in southeastern
Washington
Hanford site was established in 1943 to produce
plutonium for the production of nuclear weapons
that were used in World War II and continued
throughout the Cold War.
B-Reactor
(1944-1968)
Produced the plutonium used in “Fat man” bomb dropped
over Nagasaki in August 1945.
The production of plutonium ceased in 1987.
55 million gallons of high level radioactive
waste was stored in 177 underground tanks.
Clean-up began May 15, 1989.
www.hanford.govWaste tanks at Hanford site in Washington
26. Why glass?
- Reduces the volume of waste by
75%.
- High chemical durability over
long term.
- Commercial vitrification plants
operate in France, U.K. an
Belgium produce about 1000
metric tons per year of such
vitrified waste (2500 canisters)
and some have been operating for
more than 16 years.
The nuclear waste from the production of
nuclear electrical energy of one person’s
entire life is contained in the glass in
hand.
27. Nuclear waste vitrification in USA
The U.S. Department of Energy (DOE) is
building a Tank Waste Treatment and
Immobilization Plant (WTP) at Hanford site in
Washington state.
Vitrification plant at Hanford
View inside a Joule Heated Ceramic Melter
(JHCM) that will be used to vitrify the
nuclear waste into borosilicate glass at
1150 °C.
Although the process of nuclear waste immobilization via vitrification seems simple, it is
plagued by several complex practical problems starting from design of glass compositions
(owing to the compositional complexity of nuclear waste), to processing in glass melters, and
finally to long term performance of the vitrified waste forms.
Our research is focused on the following three problems…
28. Challenges with vitrification - USA
Problem#1 Spinel crystallization in glass melters
The cost of vitrifying radioactive waste is directly proportional to the volume of glass to be
produced. It is therefore desirable to maximize waste loading in glass to decrease the overall
volume, but without posing unacceptable risk for the melter operation.
The major factor limiting waste loading in
nuclear waste glasses is the precipitation,
growth, and subsequent accumulation of
spinel crystals (Fe, Ni, Mn, Zn, Sn)II(Fe,
Cr)III
2O4 in the glass discharge riser of the
melter during idling.
Once formed, spinels are stable
to temperatures much higher than
the typical JHCM operating
temperatures (1150–1200 °C).
This can result in clogging of the melter discharge channel, and interfere
with the flow of glass from the melter
29. Challenges with vitrification - USA
Problem#2 Crystallization vs. chemical durability
Schematic cross-section of an
underground steel tank depicting
layer by layer arrangement of the
radioactive and chemical waste.
- The high level radioactive waste at Hanford is rich
in sodium and alumina (Al2O3).
- The strategy is to convert this waste into borosilicate
glass, with maximized waste loading.
- Increasing concentration of Na2O and Al2O3 in these
glasses results in crystallization of nepheline
(Na2O•Al2O3•2SiO2) based phases.
- Since nepheline crystallization results in removal of
1 mole of Al2O3 and 2 moles of SiO2, this decreases
the chemical durability of final waste form.
30. Challenges with vitrification - USA
Problem#3 Volatile radioactive species – for example, iodine
- The 2011 Fukushima Daiichi nuclear disaster was
one of the worst nuclear incidents in World history.
- The release of large amount of radioactive iodine
(129I, t1/2 = 1.6 x 107 y), and cesium in Pacific ocean
will be disastrous for the flora and fauna of ocean.
- According to scientists, these radioactive elements
will be adsorbed by marine life, and will eventually
make their way up the food chain, to fish, marine
animals, and humans.
Fukushima Nuclear Disaster
No country has a defined protocol for immobilization of radioactive iodine as iodine is not
amenable to vitrification. For example, radioactive iodine in U.K. is currently discharged to sea.
Innovative synthesis routes need to explored for development of
ceramic waste forms for immobilization of radioactive iodine at low
temperature (<200 °C) .
31.
32. But glass still breaks….
https://youtu.be/7j9hluDLWIU
Brittleness of glass has been perceived as its gravest handicap. Over the centuries, accepting this
handicap and benefitting from optical properties and universal processability, glasses have found their
role in applications with low levels of tensile stress.
There is very high demand for novel approaches towards stronger, or more precisely, damage resistant
glasses.
33. Aluminosilicates – Backbone of specialty glasses
Corning Gorilla Glass
Ultra-smooth and Ultra-Strong Ion exchanged Glass
[Adv. Funct. Mater. 23 (2013) 3233-3238]
Used as cover glass on 4.5
billion devices
Property Value
Density 2.42 g/cm3
Young’s Modulus 65.8 GPa
Poisson’s ratio 0.22
Shear Modulus 26.0 GPa
Vickers hardness (200 g load)
Un-strengthened 489 kgf/mm2 (4.79 GPa)
Strengthened 596 kgf/mm2 (5.84 GPa)
Fracture Toughness 0.67 MPa m0.5
34. Aluminosilicates vs. Aluminates
Glass forming region in Na2O-Al2O3 SiO2 system (mol.%)
[Ref: Mysen and Richet, Silicate Glasses and Melts, Elsevier]
Vicker’s hardness: 4 – 6 GPa
Young’s modulus: 60 – 85 GPa
Fracture toughness: ~0.7 – 1 MPa m1/2
[Yoshida et al., J. Non-Cryst. Solids, 344 (2004) 37-43]
40 SiO2 – 60 Al2O3
(mol.%)
Vicker’s hardness: 8.07 GPa
Young’s modulus: 134.2 GPa
[Rosales-Sosa et al., Sci. Rep., 6 (2016) 23620]
35. Density: 2.55 – 2.85 g/cm3
Vicker’s hardness: 7.23 – 8.07 GPa
Young’s modulus: 74 – 134 GPa
Cracking Probability curves for the xAl2O3 –
(100-x) SiO2 glasses
Cracking resistance of 40 SiO2- 60Al2O3 glass
is ~7 times higher in comparison to SiO2
glass!!
[Rosales-Sosa et al., Crack – resistant Al2O3 – SiO2 glasses, Sci. Rep., 6 (2016) 23620]
Aluminosilicates vs. Aluminates
36. Challenges in synthesis of aluminate glasses
Two major challenges
1. High melting and processing
temperatures – not amenable for
synthesis in conventional glass melting
furnaces
2. Small glass forming region – high
tendency towards crystallization
76 79 82 85 88 97 Al2O3
mol.%
1800
1850
2000
1950
Phase diagram of the alumina- rich La2O3-Al2O3 system
[Fritsche and Tensmeyer, J. Am. Ceram. Soc. 50 (1967) 167]
Example
La2O3-Al2O3 glasses
Al2O3-rich glasses near eutectic of
La2O3–Al2O3 have been synthesized.
[Rosenflanz et al., Nature, 430 (2004) 761]
- Processing temperature: >1800 °C
- Small glass forming region
- Synthesized either by flame spray method or
aero-levitation technique
- Difficult to obtain monolith glasses for
practical applications.
37. Strategy to overcome these challenges
Synthesis route – melt quench vs. aero-levitation
Depending on processing temperatures
Melt-quenching
T ≤ 1650 °C
Glasses with Al2O3 ≤ 55 mol.%
Fabricate monolith samples – ready to use
T > 1650 °C
Aero-levitation technique
In collaboration with Prof. Mario Affatigato, Coe
College, Cedar Rapids, IA
Will provide glass beads which will require
further processing!!
38. Ultra-strong glasses and glass-ceramics
Map of hardness against Al2O3 content in different
material classes.
It has been shown that transparent
aluminate glass-ceramics with hardness
similar to Al2O3 can be synthesized.
Bulk rare-earth aluminate glass-ceramics
Rosenflanz et al., Bulk glasses and ultrahard nanoceramics based on alumina and rare-earth oxides, Nature, 430 (2004) 761.