Development of thermal spray powders for improved tribological and corrosive applications and cost-effective solutions

HVOF sprayed carbide/metal coatings are used widely to prevent wear and corrosion of engineering components. However, in some specific applications additional properties, such as low friction surfaces with good sliding properties and/or more improved corrosion resistances with simultaneous high wear resistance are required. Often such properties are not obtained by using conventional commercial spray powder compositions. The cost of the spray powders and sprayed coating plays very often also an important role. Therefore, cost-effective solutions are also needed. The aim of the present work is to describe the development of special hard metal powders with tailored powder compositions and structures. Experimental Cr3C2-25Ni + 10vol-% solid lubricant powders, WC-15% corrosion resistant metal binder powders, and WC-10Co-4Cr powder manufactured from recycled hard metal scrap were prepared by using the spray drying and sintering process. The powders were sprayed by High-Velocity Oxy-Fuel (HVOF) spray process. The microstructures of the developed powders and coatings are reported.