Preparation and characterization of NiO-Cr₂O₃ high-emissivity coating

The high-emissivity powders were prepared by sold state calcination and spray drying method. The Air Plasma Spraying (APS) was adopted to prepare high-emissivity coating. The X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS), scanning electron microscopy (SEM) and DS Hemispherical emissivity measurement were used to characterized the coatings. The results showed that the doping of TiO₂ and MnO₂ to NiCr₂O₄ will lead to the lattice distortion improving the emissivity. The incorporation of Mn will lead to the mixed spinel crystal structure. At room temperature, the highest emissivity reached 0.88.