Effect of Nickel Sulfate Additives in Electrolytes for Micro-Arc Oxidation on Structure, Composition and Properties of Coatings Formed on Titanium

Abstract

UDC 544.653.2: 620.193: 620.197

DOI  https://doi.org/10.5281/zenodo.1053965

The effect of nickel sulfate additives in acid and alkali electrolytes for microarc oxidation on the structure, composition and properties of coatings formed on titanium of VT1-0 grade with the purpose of low soluble titanium anodes creating is investigated. A possibility of nickel (nickel oxide) incorporating into the coatings is established. The X-ray phase analysis showed that the coatings contain nickel oxide β-NiO with a cubic lattice, TiO₂ in the form of rutile, and also SiO₂ in the form of a high-temperature β-cristobalite. The greatest thickness and content of nickel in the surface layer, minimum anodic dissolution currents and electrical strength were obtained for coatings formed in a silicate-alkaline (3 g/L KOH + 4.5 g/L Na₂SiO₃) electrolyte with the addition of 1 g/L nickel sulfate NiSO₄.

Keywords: micro-arc oxidation, titanium, micro-arc oxidation coatings, nickel sulphate, structure, composition, anodic dissolution currents, thickness, electrical strength, low soluble titanium anodes.