EFFECT OF CARBON CONTENT ON THE FORMATION OF Ti_3SiC_2 IN THE LIQUID SILICON INFILTRATION PROCESS

摘要

In the present work, Ti_3SiC_2-based composite was fabricated by pressureless infiltrating TiC-C preform with liquid silicon. The effect of carbon content on the phase composition and microstructure is studied, and then the reaction path of forming Ti_3SiC_2 in the liquid silicon infiltration (LSI) process is discussed. The existence of carbon is beneficial to the formation of Ti_3SiC_2, and Ti_3SiC_2 only appears in the sample with enough carbon content owing to the direct reaction between silicon melt and carbon. In the LSI process, silicon melt firstly reacts with TiC to form TiSi_2 and SiC, and then Ti-Sinch eutectic is formed by dissolving the intermediate phase TiSi_2 in silicon melt. Finally, Ti_3SiC_2 is formed by the reaction between Ti-Si_(rich) eutectic and TiC with the existence of carbon.