Low temperature synthesis and formation mechanism of dense SiC coating layer by fluidized bed chemical vapor deposition

Usually, it requires extremely high temperature for preparation of SiC materials, so it is an important research direction for reducing the preparation temperature of SiC. SiC coating layer with a thickness of many microns on the ZrO₂ spherical ceramic particles was synthesized using the fluidized bed chemical vapor deposition method. Through the study of microscopic morphology and microstructure change rule of SiC coating layer deposited at different temperatures, the deposition efficiency variation rule is obtained, and it is found that the low temperature product is silicon-rich, and the high-temperature product is carbon-rich. It is also found that the addition of argon can promote the deposition reaction toward to the carbon-rich direction by experimental study of different argon contents, so dense SiC coating layer can be prepared in the condition that the temperature is significantly reduced. Based on experimental results, the diagram map of SiC phase distribution with the variation of temperature and argon concentration in the fluidized bed chemical vapor deposition system is also given.