Correlation between residual stress and abrasive wear of WC–17Co coatings

• WC-Co coating was thermally sprayed unto four metal substrates.
• A conclusive evidence on the influence of residual stress on the abrasion resistance has been established.
• The residual stresses in WC phase over the entire large sample were compressive, but quite different in the different positions.
• There was correlation between residual stresses, abrasive wear and coating properties.

This investigation had been conducted to determine the influence of residual stresses on the abrasive wear resistance of HVOF thermal spray WC–17 wt.% Co coatings, as well as to derive stress relaxation after cutting by wire electric discharge machining (EDM). The abrasive wear properties of the coatings were characterised using an ASTM-G65 three body abrasive wear machine with silica sand as the abrasive. The residual stress was measured by means of X-ray diffraction techniques, on the coated samples before and after the abrasive wear tests. Compressive residual stresses were observed in the surface layer of the large coated samples. However, stress relaxation results after cutting into small sizes were distinctly different. There was strong correlation between residual stresses in the surface layer and abrasive wear resistance, as well as yield strength of a material.