Tribological Behaviour of Thermally Sprayed Coatings at Elevated Temperatures

Hardmetal coatings prepared by high-velocity oxy-fuel (HVOF) spraying represent an advanced solution for surface protection against wear. The work presented in this paper focussed on the comparison of the tribological behaviour of WC-Co, Cr₃C₂-NiCr and (Ti,Mo)(C,N)-NiCo hardmetal coatings under dry sliding wear conditions at room and elevated temperatures (at 500°C and 700°C). The friction properties of these HVOF-sprayed coatings were studied in detail. The progression of the coefficient of friction (CoF) was measured during the pin-on-disc tests at the different temperatures. The mechanisms of wear and the heat-related changes in surface roughness and microhardness of the coatings were studied.