占空比对脉冲电镀Ni-Co-Al_(2)O_(3)-WS_(2)复合镀层摩擦学性能的影响

Effect of Pulse Duty Cycle on Tribological Properties of Ni-Co-Al_(2)O_(3)-WS_(2) Composite Coating

为提高CrNi3MoVA钢的耐磨性能,用脉冲电沉积法在CrNi3MoVA钢表面制备了Ni-Co-Al_(2)O_(3)-WS_(2)复合镀层,利用扫描电镜(SEM)和X射线衍射仪(XRD)分析镀层的表面形貌和物相结构,用纳米压痕仪和往复式摩擦磨损试验机测试镀层的纳米力学性能与摩擦学性能。结果表明:Ni-Co-Al_(2)O_(3)-WS_(2)复合镀层表面呈结节状凸起,随着占空比的增加,镀层表面结节密度减少,(111)晶面择优取向更加明显。占空比为0.1的复合镀层拥有最高的硬度7.24GPa,最低的平均摩擦系数0.38和体积磨损率1.52×10^(-4) mm^(3)·(N·m)^(-1)。镀层中的n-Al_(2)O_(3)颗粒会支撑在摩擦面上减少摩擦副间的接触面积,同时与n-WS_(2)颗粒与在剪切作用下脱落形成润滑膜,发挥协同减磨作用提高镀层摩擦学性能。

Ni-Co-Al_(2)O_(3)-WS_(2) composite coating was prepared on the surface of CrNi_(3)MoVA steel by pulse electrodeposition to improve the wear resistance of CrNi_(3)MoVA steel.The surface morphology and phase structure of the coating were analyzed using scanning electron microscopy(SEM)and X-ray diffraction(XRD),and the nano mechanical and tribological properties of the coating were tested using a nanoindentation instrument and a reciprocating friction and wear tester.The results showed that the surface of the Ni-Co-Al_(2)O_(3)-WS_(2) composite coating exhibited nodular protrusions.With the increase of the duty cycle,the density of nodules on the coating surface decreased,and the preferred orientation of the(111)crystal plane became more obvious.The composite coating with a duty cycle of 0.1 had the highest hardness of 7.24 GPa,the lowest average friction coefficient of 0.38,and a wear rate of-41.52×10 mm^(3)·(N·m)^(-1).The n-Al_(2)O_(3) particles in the coating can support on the friction surface to reduce the contact area between the friction pairs,and at the same time,they can detach with the n-WS_(2) particles under shear to form a lubricating film,exerting a synergistic anti wear effect to improve the tribological performance of the coating.