Microstructure and properties of WC/diamond/Co-based gradient composite coatings on high-speed steel fabricated by laser cladding

Improving the wear resistance and corrosion of high-speed steel (HSS), WC/diamond/Co-based gradient composite coatings were produced on HSS substrates by laser cladding with different composition powder mixture (Co-Cr alloy powder, 80Co-Cr powder+20WC, 53Co-Cr powder+40WC+7diamond, wt%). The macromorphology, microstructures, phase characterized optical microscope (OM), scanning electron microscopy (SEM) equipped energy-dispersive spectrometry (EDS), X-ray diffraction (XRD) techniques. microhardness, resistance, also investigated, respectively. results indicate that prepared layer has a fine morphology cross sections transition grain size been achieved. microhardness result presents distribution along depth coating. is strengthened due to dispersions M7C3 (M Fe, Cr), Co3C, CrCo, Cr3C2, Fe3C in coating, highest 1342 HV0.2 can be detected layer. friction coefficient values range from 0.27 0.40, which much lower than substrate (0.50–0.60). Furthermore, loss (1.1 mg) decreases more 3 times comparing (3.5 mg). polarization show excellent reach value 236488.1 Ω·cm2. mechanical properties chemical metallurgical combination between particle (WC, diamond) adhesive obtained cladding, improves surface.