Development of high infrared emissivity porous ceramic coating using pre-synthesized flower-like CeO2 powder for high temperature applications

In this article, a unique high infrared emissivity porous ceramic coating was prepared by slurry spraying method. In the first step, flower-like CeO2 powder particles were synthesized by precursor pyrolysis method using Ce-2(CO3)(3)center dot 8H(2)O as the transition phase. Subsequently, flower-like CeO2 ceramic particles (filler) and silicate (binder) were deposited by air spraying. The microstructure and phase composition of the prepared particles and the ceramic coating were examined using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). High temperature performance of the coating was assessed by conducting prolong isothermal oxidation and thermal shock tests. Infrared emissivity of the coating was tested at 750 degrees C by employing infrared radiation instrument. The prepared coating exhibited excellent high temperature resistance and high infrared emissivity (epsilon(3-5 mu m) = 0.887, epsilon(8-14 mu m) = 0.889 and epsilon(2.5-19 mu m) = 0.893) at 750 degrees C. This was attributed to the presence of a large number of pores (within and among CeO2 particles) in the coating. In the end, possible mechanisms related with high infrared emissivity of the coating were discussed in detail.