Exposure effects of strong alkaline conditions on the microscale abrasion-corrosion of D-gun sprayed WC-10Co-4Cr coating

The synergistic effects between abrasion and corrosion for detonation gun (D-gun) sprayed WC-10Co-4Cr coatings have been studied for alkaline conditions. Comparisons between exposed and freshly polished coating surfaces in strong NaOH solutions (pH 11) show that significantly lower wear rates were seen for the exposed surface due to a negative wear-corrosion synergy. The negative synergy was seen to increase with increasing sliding distances for both fresh and exposed surfaces. The physical mechanisms of this negative synergy are discussed. The effect of anodic surface treatments on wear-corrosion to elucidate the influence of corrosion on the negative synergy is also reported. (c) 2007 Elsevier Ltd. All rights reserved.