等离子喷涂纳米WC-12％Co涂层与陶瓷和不锈钢配副时的摩擦磨损性能对比研究

Comparative Study of the Friction and Wear Behavior and Wear Mechanism of Plasma Sprayed WC-12% Co Coatings Matched with Ceramic and Stainless Steel Balls under Dry Sliding Condition

利用大气等离子喷涂技术制备了纳米和微米WC-12% Co涂层,采用SRV摩擦磨损试验机考察了纳米和微米WC-12%Co涂层在干摩擦条件下分别与Si3N4陶瓷球和不锈钢球配副时的摩擦磨损性能.结果表明:在相同试验条件下,纳米和微米WC-12% Co涂层分别与Si3N4陶瓷球和不锈钢球配副时的摩擦系数相差不大,但纳米WC-12% Co涂层的抗磨性能明显优于微米WC-12% Co涂层;2种涂层的磨损机制差异亦较小,纳米涂层在低载荷下的主要磨损机制为微断裂和轻微磨粒磨损,而在较高载荷下的磨损机制为硬质相的剥落和磨粒磨损;微米涂层在较低载荷下的磨损机制为微断裂和磨粒磨损,在较高载荷下为疲劳磨损.在相同试验条件下,纳米WC-12% Co涂层的磨损表面损伤明显较轻微.

Nanostructured and conventional WC-12% Co coatings were deposited on stainless steel substrate using atmospheric plasma spraying. The friction and wear properties of the coatings sliding against silicon nitride ceramic ball and stainless steel ball under dry condition were investigated using an SRV friction and wear tester. As slid against the ceramic and stainless steel counterparts under the same conditions, the results show that the two types of plasma sprayed WC-12% Co coatings exhibited minor differences in friction coefficients and wear mechanism. Both nanostructured and microstructured coatings were dominated by slight micro-cracking and abrasive wear at relatively lower load, while they were characterized by severe abrasive wear and brittle fracture at relatively larger load. However, the nanostructured coating experienced less worn surface damage and showed much better wear resistance than the conventional one under the same testing condition. This could be largely attributed to the more compact microstructure and higher microhardness, cohesion, and adhesion to substrate of the nanostructured WC-12% Co coating as compared with the conventional coating.