High emissivity coating on C-263 substrate for high temperature applications

An aluminium phosphate based high emissivity coating has been deposited on Ni based superalloy C-263 by dip coating method wherein the substrate was immersed in a chemical sol followed by curing of the green coating. Deposition of the coating by spraying the sol on the substrate surface has also been explored. The presence of carbon imparted high emissivity to the coating. Depending on the thickness of the coating, it exhibited an emissivity value of 0·6–0·9 in the wavelength range of 2.5–25 μm. The coating was found to offer good oxidation resistance to the substrate. Cyclic oxidation performance of uncoated and coated substrates has been evaluated at 800 and 1000°C for 100 h in air.