Effects of VC additions on the mechanical properties of bimodal WC–Co HVOF thermal sprayed coatings measured by nanoindentation

• Bimodal VC-doped coatings showed better mechanical properties than commercial systems.
• Nanoindentation helped studying H and E of phases present in HVOF WC–VC–Co coatings.
• Deconvolution of indentation data was used to study H and E of phases in the coatings.

Measurement of mechanical properties in cermets is complex since they are formed by several phases. How to quantitatively determine the relationship between the performance and the complex microstructure of this particular group of materials, especially when analyzing the effect of the reinforcement phase, is still one of the top challenging problems yet to be solved. Hardness and elastic modulus of bimodal WC–Co HVOF thermal spray coatings doped with vanadium carbide (VC) additions were studied by performing a statistical analysis of nanoindentation results. A mathematical deconvolution procedure and a Weibull distribution analysis of hardness and elastic modulus results are proposed to identify the individual contribution of each phase to the mechanical properties of different WC–12Co coatings. Both analysis methods allowed to detect a reinforcing effect of vanadium on the hardness and elastic modulus of bimodal VC-doped coatings. The combination of VC additions and a bimodal WC particle size distribution in the WC–Co coatings proved successful in increasing their mechanical properties, as the coatings processed in this work showed better mechanical properties than that reported in the literature for coatings having exclusively a bimodal WC particle size distribution or those only doped with VC additions.