超音速火焰喷涂CoCrAlSiY合金涂层的摩擦磨损性能

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

采用超音速火焰喷涂技术制备CoCrAlSiY合金涂层,研究了该涂层的微观结构、力学性能,以及在不同载荷(2,5,8 N)下的摩擦磨损性能。结果表明:CoCrAlSiY合金涂层主要由CoCr_(2)O_(4)、CoAl和α-Al2O_(3)相组成,各物相分布均匀,涂层致密;涂层的硬度为(7.41±0.16) GPa,与其他同类合金涂层硬度相近;在2,5,8 N载荷下摩擦磨损时,CoCrAlSiY合金涂层的平均摩擦因数分别为0.33,0.24,0.22,对应的磨损率分别为3.52×10^(-5),4.85×10^(-5),5.58×10^(-5)mm^(3)·N^(-1)·m^(-1);低载荷(2 N)下的磨损机制主要是黏着磨损和磨粒磨损,高载荷(5,8 N)下涂层发生脆性断裂而大块剥落;在摩擦磨损过程中涂层表面形成氧化物,特别是在5 N和8 N载荷下,磨损表面出现大量α-Al2O_(3)和CoCr_(2)O_(4)等氧化物。

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 CoCr_(2)O_(4),CoAl and α-Al2O_(3)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)mm^(3)·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-Al2O_(3)and CoCr_(2)O_(4)appeared on the wear surface.