Friction and Wear Properties of CoCrAlSiY Alloy Coating Prepared byHigh Velocity Oxy-Fuel Spraying

CoCrAlSiY alloy coatings were prepared by high velocity oxy-fuel spraying. The microstructure and mechanical properties as well as the friction and wear property under different loads (2, 5, 8 N) of the coating were studied. The results show that the CoCrAlSiY alloy coating was composed of CoCr₂O₄,CoAl and α-Al₂O₃ phases and the phases distributed uniformly. The coating was compact. The hardness of the coating was (7.41±0.16) GPa, which was close to that of other similar alloy coatings. During friction and wear under 2, 5, 8 N loads, the average friction coefficients of the CoCrAlSiY alloy coating were 0.33, 0.24, 0.22, and the corresponding wear rates were 3.52×10^-5, 4.85×10^-5, 5.58×10^-5 mm³·N^-1·m^-1, respectively. The wear mechanisms under low load (2 N) were mainly adhesive wear and abrasive wear; under high loads (5, 8 N), brittle fracture occurred to the coating and large pieces peeled off. During friction and wear, oxides were formed on surface of the coating. Under 5 N and 8 N loads, a large number of oxides such as α-Al₂O₃ and CoCr₂O₄ appeared on the wear surface.