The effect of current frequency on the structure, composition and properties of oxide layers formed by plasma electrolytic oxidation on aluminum-silicon alloy

Abstract

Oxide layers formed by plasma electrolytic oxidation (PEO) on pre-eutectic aluminum-silicon alloy 361.0 (9.8 wt.% Si) at various current pulse frequencies (50, 500, and 1000 Hz) were investigated. Scanning electron microscopy (SEM), energy dispersive X-ray microanalysis (EDXMA), x-ray diffraction analysis (XRD) were applied for the investigation of the oxide layers. Thickness, roughness, microhardness, wear resistance and thermal conductivity of the obtained oxide layers were measured. It was found that at a forming current frequency of 500 Hz, the best productivity of forming of the oxide layer is achieved, and the layer has the best hardness and wear resistance, and the smallest roughness.