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Chemical aspects of antiballistic cermets preparation
Brožek, Vlastimil ; Kubatík, Tomáš František ; Chráska, Tomáš ; Mušálek, Radek ; Janata, Marek ; Mastný, L.
The paper aims to demonstrate the possibilities of metal-ceramic material deposition on different types of metal or ceramic substrates using plasma deposition. A number of self-supporting components and the preparation of metal-braced composites are described and the results of plasma depositions of two particular extremely hard ceramic materials, boride and nitride of titanium are presented. The plasma deposition of these material is performed in technological conditions which prevent undesirable high-temperature oxidation. The paper describes deposition conditions that may lead to materials suited to create anti-ballistic protection and complicated shapes or improve parameters of surface layers of present anti-ballistic ceramics.
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Ceramo-metallic materials of the Ti-B-C and Ti-B-N systems
Brožek, V. ; Doležal, J. ; Novák, M. ; Ctibor, Pavel ; Kolman, Blahoslav Jan
Products prepared by the sintering of titanium and boron carbide powder and by the sintering of titanium and boron nitride powder were studied. The sintering was performed at 2,000 °C under the pressure of 6 GPa in a high-pressure apparatus of BELT-type with sufficient holding time to reach thermodynamic equilibrium. The results of chemical and phase composition analyses were compared with thermodynamic prediction of possible reactions in the system. We proved the preferential formation of borides TiB and TiB2 prior to the carbides or nitrides formation. The products, which may be considered Ti-(TiB,TiB2)-TiN or Ti-(TiB,TiB2)-TiC cermets, were analysed in order to determine their microstructure, phase and chemical composition and their influence on mechanical properties such as hardness or elastic modulus. This work precedes similar study which will be performed using the same powders processed by plasma spraying, which enables to stabilize high-temperature phases by rapid cooling.
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Nitride-based materials in nanotechnologies
Dufek, V. ; Brožek, Vlastimil
The contribution draws attention to the research results of nitrides in the Czech Republic. The nanotechnology of TiN is on the world top, but the state of silicon and boron nitrides production where we in certain sense surpassed the world niveau deceased. PRAMET Šumperk does not continue in cubic BN and OVU Karlštejn in hexagonal BN development. The information from Bayreuth University indicates that nanoclusters of fullerene ACNR (Agregated Carbon NanoRods) can reach the hardness higher than that of diamond. The same is valid for boron nitride superhard materials.
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