Metastable Phase Formation, Microstructure, and Dielectric Properties in Plasma-Sprayed Alumina Ceramic Coatings

The need for new solutions electrical insulation is growing due to the increased electrification in numerous industrial sectors, opening door innovation. Plasma spraying a fast and efficient way deposit various ceramics as insulators, which are used conditions where polymers not suitable. Alumina (Al2O3) among most employed coating industry since it exhibits good dielectric properties, high hardness, melting point, while still being cost-effective. Various parameters (e.g., feedstock type, spray distance, plasma power) significantly influence resulting terms of microstructure, porosity, metastable phase formation. Consequently, these be investigated estimate impact on properties plasma-sprayed alumina coatings. In this work, coatings with different distances have been prepared via atmospheric (APS) copper substrates. corresponding formation analyzed optical microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM). Moreover, we present an in-depth analysis fundamental e.g., direct current (DC) resistance, breakdown strength, loss tangent, permittivity. Our results show that decreasing distance reduces resistivity from 6.31 × 109?m (130 mm) 6.33 108?m (70 mm), at same time enhances ?-Al2O3 phase. Furthermore, space charge polarization determined main mechanism low frequencies.