Preparation and study of porous transition metal-doped coatings on electric vacuum ceramics for suppressing surface flashover

Insulation failure caused by surface flashover is the main problem of high-voltage equipment. In this study, screen printing and solid-state sintering techniques were adopted to prepare Cr₂O₃-based composite coatings containing elements such as Cu, Mg, Mn, Ti, and Zn on the surface of alumina ceramics, in order to enhance their compressive resistance. SEM shows that Cr/Cu coating has the largest uniform porosity, AFM indicated that the roughness of the Cu₂O coating was increased by 60 % compared with the control group. The SPD test shows the Cr/Cu coating has the slowest potential decay, with a deep trap level of 0.96 eV and density of 5.12 eV^-1m⁻³, and a shallow trap level of 0.78 eV with a density of 2.36 eV^-1m⁻³. By changing the surface and electrical properties of Al₂O₃ ceramics to improve its flashover performance, it provides an effective strategy for vacuum insulation applications.