Engineers from InnoTech Alberta evaluated a coating consisting of tungsten carbide overspray for parts requiring moderate-to-low wear resistance. Tungsten carbide-based metal matrix composite coatings are widely used in the resource sector. Typically, the coatings are applied by high velocity oxy-fuel (HVOF) spraying, and can provide excellent levels of protection against wear and corrosion. However, it has disadvantages: It is relatively high in cost due to the high proportion of WC in the powder blend, and the low deposition efficiency of the HVOF powder. It is common for approximately 50% of the powder to be deposited on a substrate, with the excess “over-spray” collected and disposed of.
This study will look at using this “over-spray” in a coating for moderate to low wear applications, rather than disposing of it. The development of a lower-cost coating with a degree of corrosion resistance was studied. The coating is comprised of “over-spray” WC-based powder blended with a standard 316-grade stainless steel. Microstructure, chemical analysis, corrosion resistance, and abrasion wear performance of the overlay were discussed in the presentation.
Johanna Meier, Gary Fisher, InnoTech Alberta
