Incorporation of Iron (II) Sulfate Additive into Nanocomposite Coating Formed by Plasma Electrolytic Oxidation of Aluminium Alloy

摘要: Plasma electrolytic oxidation (PEO), based on the traditional anodic oxidation, is a promising novel process to form ceramic-like coatings on valve metals (Al, Mg and Ti, etc.) with appropriate corrosion and wear resistance, biomimetic and also thermal barrier properties. A series of chemical, electrochemical and plasma chemical reactions take place on the sample’s surface in a suitable electrolytic by relatively high applied voltage. The obtained surface coatings can greatly improve the corrosion, wear and high temperature oxidation resistance of the valve metal. The microstructure of PEO coatings are related with the chemical composition and concentration of the electrolyte, current density, mode of power supply and the substrate composition, in which, the effect of chemical composition of the electrolyte on the final properties of the PEO coatings is quite important. In this view, some attempts have been made in this study, to improve the properties of PEO coatings. We investigate the incorporation of Iron (II) sulfate into electrolyte of PEO for 1010 aluminium alloy using direct current. To reach nanocomposite coating, silicon nitride nanoparticles were added to electrolyte as suspension. The effects of Iron (II) sulfate additive on the voltage response, mass change, microstructure, composition, wear and corrosion resistance of PEO coatings were investigated.