REACTION SINTERING PHENOMENA OF SELF-PROPAGATING HIGH-TEMPERATURE SYNTHESIS-DERIVED CERAMIC POWDERS IN THE TI-SI-C SYSTEM

Sintering phenomena of self-propagating high-temperature synthesis (SH S)-derived powders often have a character of densification accompanied by a reaction in solid and/or liquid phase. The problem is discussed in the case of preparation of Ti3SiC2-based materials. This novel lami nate ceramics has some unique properties like low hardness, high fract ure toughness, corrosion resistance and ductile character at elevated temperature. Because of specific mechanisms during rapid combustion-ty pe SHS reactions, it is possible to prepare Ti3SiC2-rich powders that can be used as precursors for preparation of Ti3SiC2-based polycrystal s. Densification of these powders occurs with formation of transient m etallic liquid phase. As a result, dense polycrystals with controlled microstructures in form of particulate composites with Ti3SiC2 matrix and controlled TiC inclusions can be obtained. The reactions occurring during preparation of Ti3SiC2-based composites with WC and B4C are al so discussed.