Hard chromium substitution using HVOF coatings

Electroplated hard chromium coatings have long been used to improve the wear and/or corrosion resistance of components. However, concerns over the health problems associated with hexavalent chromium solutions have led to increasing regulation of this process route. One promising substitute for hard chromium is 'cermet' layers (e.g. Cr3C2–NiCr and WC–CoCr) which may be deposited by the high velocity oxyfuel process. High velocity oxyfuel coatings were characterised by microscopy, X-ray spectroscopy, density and a microabrasive wear test. The WC–CoCr coating provided the best overall performance and is an excellent candidate for hard chromium substitution.