Effect of WC particle size on the abrasive wear of thermally sprayed WC-Co coatings

Four types of WC-Co powders with different WC particle sizes are sprayed to produce WC-Co coatings with a Jet-Kote gun using a gas mixture of C₂H₂-30% C₃H₆ and pure propylene as fuel gases. The carbide size in sprayed high velocity oxy-fuel (HVOF) WC-Co coatings is measured from the microstructure. The abrasive wear of the coatings is characterized using a Suga abrasive wear tester. The abrasive wear mechanism of thermally sprayed WC-Co is discussed. The relationship between the relative wear of WC-Co coatings and carbide sizes is established according to the strength theory on hard alloy. The correlation with experimental data proves that the relative abrasive wear of WC-Co coating is proportional to square root of relative carbide size.