The effect of the decomposition of CH₄ gas on polycrystalline SiC coating on SiC ceramics using Si vapor

Abstract

We investigated the application of polycrystalline SiC coating on SiC ceramics using vapor from a Si melt as a Si source and C2H2 generated by decomposition of CH4 gas as a C source. First, the temperature distribution and gas flow in the furnace, the decomposition behavior of CH4 gas, and the production rate were calculated using the simulation software Virtual Reactor. Based on these numerical results, the structure of the furnace and its internal layout were decided. Next, SiC coating on SiC ceramics was performed with two different furnace layouts, and the generated SiC coating layer was evaluated by observation of the microstructure. With a CH4 gas flow rate of 50 sccm and a pressure inside the furnace of 0.5 atm, SiC coating with a coating rate of 26 μm/h was achieved.