Influence of High-Enthalpy Atmospheric Plasma Spraying Process Parameters on Microwave Dielectric Properties of Y 2 O 3 Coatings

The low-dielectric inorganic adhesive is an important component of electromagnetic wave absorption coatings due to impedance matching with the atmospheric environment. Herein, high-enthalpy atmospheric plasma spraying (HE-APS) equipment is utilized to prepare Y2O3 ceramic coatings, and the influence of spraying power on dielectric and physical properties of Y2O3 ceramic coatings is systematically investigated. The surface and cross-sectional SEM images of Y2O3 coating show that the overall coating morphology is smooth and less porous at high spraying power. This result is consistent with the trend of coating density and porosity. The XRD pattern demonstrates that the Y2O3 coating possesses a stable cubic structure. The experimental results reveal that the dielectric properties of Y2O3 coating are mainly affected by the porosity. According to the dielectric mixing rule of composite materials, Y2O3 coating exhibits the minimum density of 4.86 g/cm3 and permittivity of 9.70 under the spraying power of 55 kW. The current work highlights the feasibility of Y2O3 as a low-dielectric inorganic adhesive in the field of electromagnetic wave applications.