Tribological performance and corrosion resistance of HVOF WC-17 wt. % Co coatings: influence of micro-to-nanoscale morphology

We investigated the wear and corrosion properties of high-velocity oxygen fuel (HVOF)-sprayed microstructured and near-nanostructured WC-17 wt. % Co coatings fabricated on steel substrates. The near-nanostructured variant exhibited a high hardness value of ~991 Hv, a low corrosion rate of ~0.10624 MPY, a low wear rate of ~0.0012 mm³/m, and a low cumulative wear volume loss of ~0.1304 mm³. Corrosion effects resulted in a reduction of hardness by 23.02% and 30.07% for the near-nanostructured and microstructured samples, respectively; moreover, the wear volume loss of the microstructured coating was 30.02% higher compared to the near-nanostructured coating. We attribute the enhanced corrosion and wear resistance of the near-nanostructured HVOF coating to its dense and uniform surface morphology, low porosity, minimal decarburization, and high hardness. Triboscopic imaging studies further confirmed a low degradation rate, high wear resistance, and minimal wear volume loss.