含Ag@Ni核壳结构粉体镍基复合涂层的多循环高温摩擦学性能

Tribological properties of Ni-based composite coatings with addition of Ag@Ni core−shell particles over multiple thermal cycles

为了抑制Ag的扩散,采用化学镀方法制备Ag@Ni核壳结构粉体,并利用大气等离子喷涂技术制备NiCrAlY-Mo-Ag@Ni涂层,详细研究核壳结构设计对涂层在高温循环工况下的力学及摩擦学性能的影响。研究结果表明:Ag的核壳结构设计可以提高镍基涂层中Ag与NiCrAlY的界面结合强度,进而显著提高复合涂层的硬度。Ni覆层有效地抑制了Ag在高温摩擦过程中的扩散与耗散。800℃时NiCrAlY-Mo-Ag@Ni涂层的摩擦因数仅为0.25,磨损率仅为1×10^(-5)mm^(3)/(N·m),显著低于NiCrAlY-Mo-Ag涂层。同时,Ag的核壳结构设计使得涂层在高温多循环工况下始终保持良好的自润滑性和耐磨性。

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℃are only about 0.25 and 1×10^(−5)mm^(3)/(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.