Arc Sprayed Ti-N Coatings for Protection Against Corrosion and Wear

Abstract

TiN reinforced Ti coatings were produced by using the arc spraying process. TiN hard phases were synthesized during spraying using Ar/N2 reactive atomizing gas. The spray process was realised in an air atmosphere with a shrouded gun and in a chamber with closed loop Ar/N2-gas atmosphere. The content of TiN phases in Ti-coatings was increased by rising the N2-amount in atomizing gas during spraying. Sprayed coatings obtained a graded hardness ranging from 450HV0.1 near the substrate up to 650HV0.1 near the top (mean values). TiN-particle precipitations exhibited micro hardness up to 1350HV0.1. Structure investigations of manufactured coatings proved that they consist of pure titanium, titanium nitrides and small amounts of titanium oxides. Wear resistance of the coatings, tested by Taber Abraser and Pin on Disc, decreases from the coating surface to the substrate. According to Kesternich test, Ti/TiN-arc sprayed coatings exhibit good corrosion resistance.