Leszek Chlubny

SHS Synthesis of the Materials in the Ti-Al-C-N System Using Intermetallics

Materials in the Ti-Al-C-N system due to their specific heterodesmic structure show pseudo-plastic properties. Direct synthesis of these compounds from respective elements requires high-temperature and long-lasting reaction. Presented work shows attempts to prepare some ternary compounds using self-propagating high-temperature synthesis (SHS). Intermetalic precursors, TiAl and Ti3Al, were used to synthesize fine and sinterable powders of 211 and 312 complex structure materials.

Sintering and Hot-Pressing of Ti2AlC Obtained by SHS Process

Some of ternary materials in the Ti-Al-C system are called MAX-phases and are characterised by heterodesmic layer structure. Their specific structure consisting of covalent and metallic chemical bonds influence its semi-ductile features locating them on the boundary between metals and ceramics, which may lead to many potential applications, for example as a part of a ceramic armour. Ti2AlC is one of this nanolaminate materials. Self-propagating High-temperature Synthesis (SHS) was applied to obtain sinterable powders of Ti2AlC Utilization of heat produced in exothermal reaction in adiabatic conditions to sustain process until all substrates are transformed into product is one of the advantages of the method that result in low energy consumption and low cost combined with high efficiency. Different substrates were used to produce fine powders of ternary material. Phase compositions of obtained powder were examined by XRD method. Than selected powders were used for sintering in various temperature both in a presureless sintering and hot-pressing in argon atmosphere. Properties and phase composition of obtained products were examined.

Composites Produced by SHS Method – Current Development and Future Trends

Basic stages of progress in composite materials, prepared by SHS method, from a scientific approach to a promising and rapidly developing applications are discussed in this paper. The systematic review of different forms of composites prepared directly by SHS or by SHS-origin precursors is presented. Powders are usually the starting material for manufacturing of ceramic and a lot of attention has been paid to find new routes for synthesis powders in form of nano or micro particles. The present work is aimed at efficient and convenient powder processing by SHS as an important target for future composites technology. The use of SHS may bring a considerable development in ceramic technology, by enabling a manufacturing of sinterable, high-purity nano or micro powders. It can be demonstrated in different ceramic systems explored by the authors and coworkers using SHS e.g. (a) Si-C-N, (b) Al-O-N as well as (c) Ti-Si-C-N. Rapid combustion conditions were successfully used to manufacturing composite powders and nanopowders suitable for preparing multiphase composite materials having controlled properties.