Glass-ceramic precursors in the B2O3‒SiO2‒MxOy systems (M ― Ti, Zr, Cr) as a source for producing fine-dispersed mixtures of high-melting carbides and borides

Author(s):  
T. V. Kotsar ◽  
D. P. Danilovich ◽  
S. S. Ordanyan
Author(s):  
T.R. Dinger ◽  
G. Thomas

The use of Si3N4, alloys for high temperature, high stress structural applications has prompted numerous studies of the oxynitride glasses which exist as intergranular phases in their microstructures. Oxynitride glasses have been investigated recently in their bulk form in order to understand their crystallization behavior for subsequent Si3N4 applications and to investigate their worth as glass-ceramic precursors. This research investigates the crystallization sequence of a glass having a normalized composition of Y26Si30Al11 ON11 and lying in the A1N-Y2O3-SiO2 section of the Y-Si-Al-O-N system. Such glasses exist as intergranular phases in the technologically important Y2O3/Al2O3-fluxed Si3N4 alloys.


2000 ◽  
Vol 192-195 ◽  
pp. 337-340
Author(s):  
A. Krajewski ◽  
A. Ravaglioli ◽  
M. Mazzocchi ◽  
G. Foresti

2013 ◽  
Vol 278-280 ◽  
pp. 418-421
Author(s):  
Na Zhao

the controlled crystallization and characterization of Li2O-Al2O3-SiO2-P2O5 glass ceramic by XRD and numerical calculus. The results indicate that the controlled model of crystallization is the process though controlling the growing size of crystallization grain by forming residual glass phase with high melting point, and proper high-melting supplement such as Y2O3、Al2O3 can reduce crystal grain size at the same time that does not change nucleation quantity. At last, transparent glass-ceramic with little crystal grain can be obtained by the theorizing analytic model.


Author(s):  
Stuart A. Maloy

MoSi2 has recently been investigated as a potential material for high temperature structural applications. It has excellent oxidation resistance up to 1700°C, a high melting temperature, 2030°C, and a brittle-to-ductile transition temperature at 900-1000°C. WSi2 is isomorphous with MoSi2 and has a body-centered tetragonal unit cell of the space group 14/mmm. The lattice parameters are a=3.20 Å and c=7.84 Å for MoSi2 and a=3.21 Å and c=7.88 Å for WSi2. Therefore, WSi2 was added to MoSi2 to improve its strength via solid solution hardening. The purpose of this study was to investigate the slip systems in polycrystalline MoSi2/WSi2 alloys.


Author(s):  
J.M. Schwartz ◽  
L.F. Francis ◽  
L.D. Schmidt ◽  
P.S. Schabes-Retchkiman

Ceramic thin films and coatings are of interest for electrical, optical, magnetic and thermal barrier applications. Critical for improved properties in thin films is the development of specific microstructures during processing. To this end, the sol-gel method is advantageous as a versatile processing route. The sol-gel process involves depositing a solution containing metalorganic or colloidal ceramic precursors onto a substrate and heating the deposited layer to form a crystalline or non-crystalline ceramic coating. This route has several advantages, including the ability to create tailored microstructures and properties, to coat large or small areas, simple or complex shapes, and to more easily prepare multicomponent ceramics. Sol-gel derived coatings are amorphous in the as-deposited state and develop their crystalline structure and microstructure during heat-treatment. We are particularly interested in studying the amorphous to crystalline transformation, because many key features of the microstructure such as grain size and grain size distribution may be linked to this transformation.


Author(s):  
S.f. Antonov ◽  
◽  
E.F. Kutsevich ◽  
A.I. Matveeva ◽  
R.V. Bartko ◽  
...  

Variants of the intensification of the solvent dewaxing process, which increase the yield of base oils, are described. One of the promising ways to improve the technical and economic indicators of the dewaxing process is the use of modifying additives. The work shows that the introduction of a polymer additive requires a decrease in the filtration rate and, accordingly, an increase in the performance of the dewaxing unit. This results in a petrolatum with a reduced oil content, which is a qualifying factor for the production of high-melting ceresins, protective-wax components, and lubricants for various purposes.


2008 ◽  
Author(s):  
Xiaomei Guo ◽  
Kewen Kevin. Li ◽  
Xuesheng Chen ◽  
Yingyin Kevin. Zou ◽  
Hua Jiang

Sign in / Sign up

Export Citation Format

Share Document