Thermodynamic description of the sintering aid system in silicon carbide ceramics with the addition of yttrium

The Y3Si2C2 coating on the surface of the silicon carbide powders can play as an important additive to improve the sintering process of silicon carbide ceramics. A detailed thermodynamic description for the Y-Si-C system is desired to study the sintering and densification mechanisms. Coupling the first-principles calculations and CALPHAD approach, we have thermodynamically investigated the Y-Si-C with its binary sub-systems. The presently obtained thermodynamic parameters can reasonably reproduce the available experimental data. With the theoretical analysis, we have successfully elaborated the thermal behaviors of the Y3Si2C2 coating during the sintering process. Similar work on other SiC based systems may provide a solid thermodynamic basis for the development of other sintering aids in ceramics.