Low infrared emissivity of the Cr39Ni7C/inorganic silicate coatings with excellent heat-resistant

Low infrared emissivity coatings with good heat-resistant property are prepared by using Cr39Ni7C powders and inorganic silicate as filler and binder, respectively. The effects of ball-milling time and heating temperatures on both the microstructure and crystallinity of Cr39Ni7C powders as well as the infrared emissivity of the coatings are detailedly explored. The results show that large spherical Cr39Ni7C particles change into smaller flakey particles gradually with ball-milling time extending to 70 h. Meanwhile, crystallinity of Cr39Ni7C powders enhances with temperature increasing from 300 °C to 700 °C. Contributed by the small flakey particles and enhanced crystallinity, the Cr39Ni7C coating could possess low emissivity value of 0.59 at room temperature, and it further reduces to 0.55 with the temperature rising up to 600 °C. Additionally, good thermal stability is obtained due to the SiOSi space network structure and the SiOM bonding between the coatings and substrates.