Mechanical properties and microstructure of WC–10Co–4Cr and WC–12Co thermal spray coatings deposited by HVOF

Abstract

The present investigation has been conducted in order to determine the microstructural features, hardness and elastic modulus of two different WC–Co and WC–Co–Cr high velocity oxy fuel sprayed coatings. Particular emphasis has been given to the evaluation of the elastic modulus on the surface and cross-section of both coatings, employing three different indenters and the influence of the applied load on such property. For this purpose, both conventional and instrumented indentation tests were carried out on the surface and cross-section of the coatings. The elastic modulus was computed by means of the Oliver and Pharr method (1992; 2004) and compared with the values determined by means of the Marshall et al. method (1982). The values of the elastic modulus found both on the surface and on the cross-section of the samples were ∼250 GPa, which indicates a quasi-isotropic behaviour due to the uniform and dense microstructure observed along both directions.