Plasma-Electrolytic Coatings Obtained on VT1-0 Titanium with a Short Processing Time

Abstract

The possibility of obtaining thin continuous plasma-electrolyte protective oxide coatings on VT1-0 titanium in a nickel sulfate alkaline electrolyte without the addition of silicates in the sparking mode was studied. The elemental composition and the microstructure of coatings manufactured via plasma electrolytic oxidation (PEO) both on the substrate and after the destruction of the coating in 25% sulfuric acid were studied. As a result of the research, a possibility of forming thin (1–7 μm) continuous PEO coatings, with a treatment duration of 3–10 min, respectively, was established. The introduction of additives (for example, nickel sulfate) into the electrolyte is effective when the duration of PEO is more than 10 min. It was supposed that nickel was incorporated into the coating mainly due to the action of plasma microarcs. The limited corrosion resistance of the resulting coatings in aggressive media was noted. An analysis of the elemental composition of the dry residues of the coating after destruction in a 25% sulfuric acid solution gives grounds to assume the electrochemical nature of the corrosion destruction of such coatings.