Effect of annealing treatment on the microstructure and current carrying tribological properties of in-situ formed TiO2−x coating prepared by plasma spraying

Titanium suboxide (TiO2−x) of Magnéli phases was in-situ formed by using supersonic plasma spraying with the agglomerated TiO2 powders. The effect of annealing treatment on phase constitution, microstructure, mechanical, electrical and tribological properties of the as-sprayed TiO2−x coating was analyzed. The results showed that the phase constitution and microstructure of the annealed TiO2−x coatings transformed with the annealing temperatures, which greatly affected the mechanical properties and electrical conductivity. Compared to dry friction, the friction coefficients of the coatings declined under the action of electric current. Owing to the increase in the roughness and intensification of the abrasive properties on the worn surfaces, the wear loss of the coatings increased notably under current-carrying condition.