Thermal oxidation of cold sprayed Ti-5Al-XZn coatings for tribological applications

Abstract

Room temperature tribological behavior of the thermally oxidized (at 600 degrees C for 60 h in air) low-pressure cold spray coatings fabricated on a Co-Cr alloy by deposition of Ti (85-95 wt.%) and Al (5 wt.%) powder mixture with and without the addition of Zn powder (up to 10 wt.%) were examined. At the outermost surface, the thermal oxidation caused mainly formation of a wear resistant TiO2 layer; also containing ZnO over the Zn accumulated regions of the coatings. The presence of ZnO induced a reduction in the coefficient of friction to a value as low as 0.12 against the sliding contact of the Al2O3 counterface for the coating fabricated by deposition of the 5wt.%Zn containing powder mixture.