The effect of SiC coatings microstructure on their infrared emissivity
Jia‐Bao Liu, Zhaofeng Chen, Lixia Yang, Pan Chai, Qiang Wan
Abstract
Infrared temperature measurement is widely used in the MOCVD process, and improving the surface infrared emissivity of the graphite base is beneficial to improve the temperature measurement accuracy. In this study, SiC coatings were prepared by CVD on graphite substrate using different process parameters including CVD temperature, total pressure, H2/MTS ratio. The infrared emissivity of SiC coatings with different microstructures was investigated. All SiC coatings obtained were β-SiC. The infrared emissivities of the three samples with different surface morphologies are 0.93, 0.95 and 0.97, respectively. As the surface roughness increases, the reflection and scattering of thermally radiated electromagnetic waves increases, resulting in higher infrared emissivity. The loose structure of the grain surface makes the surface electromagnetic wave and light wave resonant coupling, thus increasing the infrared emissivity.