SELF-PROPAGATING HIGH-TEMPERATURE SYNTHESIS AND REACTION MECHANISM IN Ti-W-C SYSTEM

The effects of W content, Ti powder size and preheating temperature on combustion temperature and combustion velocity in SHS of Ti-W-C system were investigated. The phase components of SHS products were examined. The reaction mechanism was studied. Uniphase (W,Ti)C can be synthesized without being preheated in the condition of W/(Ti+W)≤0.3. Preheating mixtures can accelerate the formation of (W,Ti)C. There are two reaction mechanisms in SHS reaction process, which are solution-precipitation and diffusion-solution in solid state respectively.