Tribological properties of Ni-based composite coatings with addition of Ag@Ni core-shell particles over multiple thermal cycles
(1. College of Mechanical and Electrical Engineering, Shaanxi University of Science &Technology, Xi’an 710021, China;
2. State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China)
2. State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China)
Abstract: In order to inhibit the diffusion of Ag, Ag@Ni core-shell structure particles were prepared by the electroless plating, and then the NiCrAlY-Mo-Ag@Ni coatings were prepared by atmospheric plasma spraying. The effects of core-shell structure design on the mechanical and tribological properties of the coatings over multiple thermal cycles were researched in detail. The results show that the core-shell structure design of Ag could enhance the interfacial bonding strength between Ag and NiCrAlY by the Ni-coated layer, and then improve the hardness of the coating obviously. The Ni-coated layer inhibits the diffusion and dissipation of Ag effectively in the friction process at high temperatures. The friction coefficient and wear rate of the NiCrAlY-Mo-Ag@Ni coating tested at 800 °C are only about 0.25 and 1×10-5 mm3/(N·m), respectively, which are obviously lower than those of the NiCrAlY-Mo-Ag coating. Meanwhile, the core-shell structure design of Ag endows the coating with excellent self-lubricating and wear resistance over multiple thermal cycles.
Key words: core-shell structure; Ag@Ni; Ni-based composite coating; tribological properties; multiple thermal cycles