Effect of Substrate Surface Roughness on the Splat Formation in the HVOF Spraying of WC-Co

The effect of substrate surface roughness on the splat formation and adhesion between WC-Co splat HVOF(high velocity oxy-fuel) sprayed and steel substrate are studied.The results showed that with the increase of surface roughness the restriction to flattening of splat is enhanced so that the number of spherical to nearly spherical particles became reduced while the ratio of splat with complex morphologies increased.Furthermore,the physical contact and adhesion between the WC-Co splat and substrate got better as a result of increased surface roughness.Suitable duration of grit blasting can improve the bonding strength.