Corrosion Resistance of Titanium Alloys with Oxynitride Coatings in Concentrated Inorganic Acids

摘要

We study the corrosion behavior of VT1-0, VT6s, and VT14 titanium alloys after thermodiffusion oxynitriding in 20 and 30% aqueous solutions of hydrochloric acid and in 40, 80, and 85% solutions of sulfuric acid. It is shown that the oxynitride coatings better protect titanium alloys than oxide and nitride coatings. This is explained by the specific features of the structure and chemical bonds between the atoms in the crystal lattice of titanium oxynitride. It is also shown that the formed oxynitride layer guarantees high corrosion resistances of titanium alloys in hydrochloric acid, whereas the layered structure containing the oxide and oxynitride components better protects titanium alloys in sulfuric acid.