超音速等离子喷涂NiCr-Cr_3C_2涂层的组织结构与微动磨损性能

Microstructure and fretting wear property of NiCr-Cr_3C_2 coatings prepared by supersonic plasma spray

采用超音速等离子喷涂法在1045钢表面制备NiCr-Cr_3C_2涂层,分析涂层的微观结构及化学成分以及涂层的晶粒结构,利用MICROMET-6030显微硬度仪和Nano-test 600纳米压痕仪测定涂层的显微硬度与弹性模量,通过油润滑微动摩擦磨损试验测试涂层的微动磨损性能。结果表明,NiCr-Cr_3C_2涂层为明显的层状结构,具有单晶、纳米多晶与过渡区共存的复杂晶体学结构,显微硬度HV0.3高达998,约为基体材料硬度的3倍,弹性模量为224.6GPa;涂层的微动摩擦因数随载荷增大而减小,随温度升高而增大。喷涂层的抗微动摩擦磨损性能较基体优异,摩擦因数及体积磨损量分别比基体降低36.7%和55.6%。涂层的磨损机理以磨粒磨损和疲劳剥落为主。

The NiCr-Cr3C2 coatings were deposited by supersonic plasma spraying （SPS）. The microstructures and chemical composition of the coatings were analyzed, and the grain structure was examined from the ultra-microscopic perspective; the microhardness, elastic modulus were tested and analyzed by MICROMET-6030 microhardness tester and Nano-test 600 nanoindententation apparatus, respectively. The results show that NiCr-Cr3C2 coatings have obvious layered structure, and contain complex regions such as the single crystal region, polycrystalline region, and transition region. The value of microhardness, elastic modulus are 998 HV0.3 and 224.6 GPa, respectively. The fretting friction coefficients of the coatings decrease with increasing load and increase with increasing temperature. The coating shows much better fretting wear resistance than that of the substrate. The friction coefficient and the wear volume loss are decreased by 36.7% and 55.6%, respectively. The main wear mechanism of the coating is abrasive wear and fatigue spalling.