Impact Of Co–Cr, Ni, and NiCr binder systems on the microstructure and functional properties of WC coatings produced by detonation spraying

Abstract

This study investigates the influence of metallic binder composition (Co–Cr, Ni, and NiCr) on the microstructure and performance characteristics of tungsten carbide-based coatings deposited by detonation spraying. A comprehensive characterization was carried out using scanning electron microscopy, EDS elemental mapping, microhardness testing, tribological evaluation, scratch testing, and electrochemical corrosion analysis. The results demonstrate that binder type significantly affects coating porosity, WC phase distribution, hardness, and tribological behavior. The WC–Co-Cr coating exhibited the most favorable combination of properties: the lowest coefficient of friction (0.515), the highest microhardness (1232.55 HV), the best scratch resistance, and superior corrosion resistance in 3.5 wt.% NaCl solution. The WC–Ni coating showed the lowest porosity (0.40%) due to the high fluidity of the nickel binder, while WC–NiCr demonstrated the highest porosity (2.78%) and the most pronounced susceptibility to cracking under progressive loading. The findings confirm the strong potential of detonation-sprayed WC–Co-Cr coatings for extending the service life of pipeline valves and other components operating under wear and corrosion conditions in the oil and gas industry.