Preparation and Investigation of High Emissivity Coatings Prepared by Plasma Spraying

The high emissivity coating was deposited by Air Plasma Spraying (APS). Ni2O3, Cr2O3 were the main raw materials in this study. The feedstock powder was prepared by spray drying and post-sintering at 1420 °C for 2hours. The microstructure, phase structure, flowability and bulk density of the plasma sprayed powder were characterized. The microstructure, bond strength and infrared emissivity of the high emissivity coating were also analyzed in this paper. The results reveal that the powder before and after sintering presents good flowability and is suitable for plasma spraying process. A dense coating with the bond strength of 28.14MPa was prepared successfully. The normal emissivity of the coating in all waveband is 0.87 at the temperature of 300°C, 600°C, 900°C, 1000°C, 1100°C and 1200°C