Influence of Oxidation on the High-Temperature Tribological Properties of Tungsten-Carbide-Reinforced Cu-Ni-Mn Composite Coatings

Cu-Ni-Mn alloy coatings and their associated composite coatings reinforced with tungsten-carbide (WC) particles were deposited onto a steel substrate using the manual oxy-acetylene weld hardfacing method. The sliding wear behaviors in air at 350 °C were investigated. The relative wear-resistance values of the as-deposited and the age-hardened WC/Cu-Ni-Mn hardfacing coatings with regard to the commercial Fe-Cr-C hardfacing coatings at 350 °C were 1.90 and 2.39, respectively. The excellent sliding wear-resistance performance of the WC/Cu-Ni-Mn hardfacing coatings was mainly ascribed to the hard and thermally stable WC particles embedded uniformly in the Cu-Ni-Mn metal matrix. The high-temperature wear mechanisms of the coatings were determined to be mainly abrasion and adhesion. The oxidation of the metal matrix improved sliding wear-resistance performance at high temperatures. Compared to the results at room temperature, the friction coefficients of the coating decreased, whereas the sliding wear volume loss increased slightly under dry sliding wear conditions at high temperatures.