Research on reducing infrared emissivity of 8YSZ coating by regulating microstructure

•The infrared properties of YSZ coating with layered structure is better compared with columnar structure.•The surface roughness and emissivity of YSZ coating significantly decreased after plasma surface treatment.•The YSZ coating with low roughness shows higher specular reflection in comparison with high roughness. Yttria stabilized zirconia (YSZ) has low thermal conductivity and high electrical conductivity in high temperature environment, and has great application potential in the field of infrared stealth. Herein, we used plasma spraying physical vapor deposition (PS-PVD) and air plasma spraying (APS) to prepare 8YSZ coatings with different microstructures by regulating the spraying distance and surface treatment, and explored the influence of the microstructures on the emissivity of the 8YSZ coating. The results show that the 8YSZ coating prepared by APS has a distinctive lamellar porous structure, and its emissivity is lower than that of the 8YSZ feather columnar prepared by PS-PVD. In addition, the plasma surface treatment further reduces the emissivity of the coating prepared by APS. The emissivity significantly decreased from 0.54 to 0.43 at 3–5 μm waveband along with decreased surface roughness.