LI Junfeng, LU Wu, LUO Zhengping

(Aerospace Research Institute of Materials and Processing Technology, Beijing 100076, China)

Abstract: The high-emissivity coatings with different thickness and different filler volume percentage were prepared. The transition metal oxides and boron carbide were used as fillers, and the ceramic precursor resin was used as coating forming matter. The emissivity at room temperature and 1100 K and thermal shock performance were measured. The influences of coating thickness and filler volume percentage on the emissivity and thermal shock performance were studied. It was found that the coating emissivity increased quickly as the coating thickness increased, and then became steady. The minimum coating thickness with steady emissivity was about 50 μm, and the coating emissivity at 1100 K was not less than 0.90. The high emissivity coating with the fillers content of 50vol.% has intact structure and good oxidation resistance at high temperature and no spalling after 20 times of thermal shock cycles from 1100 K to room temperature.

Key words: high emissivity coating; thickness; filler volume percentage; emissivity; thermal shock performance