Optimization of Spray Parameters in Preparation of WC-Cr₃C₂-Ni Coating by High Velocity Oxygen Fuel Spraying

WC-Cr₃C₂-Ni coatings were prepared by high velocity oxygen fuel (HVOF) spraying on the Q235 steel. The orthogonal experiment of three factors and three levels was designed by regarding spraying distance, oxygen flow rate and kerosene flow rate as variables, and the porosity, hardness and comprehensive index of the coatings were graded to obtain the best combination of spray parameters. The results show that the optimal spray parameters of WC-Cr₃C₂-Ni coating were 1 740 scfh (49 242 L·h^-1) for the oxygen flow, 7.0 gph (26.495 L·h^-1) for the kerosene flow and 330 mm for the spray distance.