The effect of tungsten carbide nanoparticles added to electrolyte on the composition and properties of oxide layers formed by plasma electrolytic oxidation on pre-eutectic silumin

Abstract

The effect of a low concentration (500 mg/L) additive of tungsten carbide (WC) nanoparticles (NPs) with a dispersion of 50–80 nm in an electrolyte on the structure, composition, and properties of oxide layers formed by plasma electrolytic oxidation (PEO) on 357.0 aluminum-silicon alloy (7.5 wt.% Si) was investigated. The oxide layers were studied by scanning electron microscopy (SEM), energy dispersive X-ray spectral microanalysis (EDXMA), X-ray diffraction analysis (XRD), and instrumental indentation. The thickness, roughness, microhardness, and wear resistance of the oxide layers were determined. It was found that the addition of WC nanoparticles at a concentration of 500 mg/L into the base electrolyte leads to an increase in the average thickness of the layer from 73 μm to 92 μm. It was found that the average microhardness was increased from 882 MPa to 1307 MPa, and the average wear was decreased from 592·10−9 g/(N·m) to 81·10−9 g/(N·m).