电沉积方式对Ni-CeO_2纳米复合镀层摩擦磨损性能的影响

Effects of electrodeposition methods on friction and wear properties of Ni-CeO_2 nanocomposite coatings

采用直流电沉积、脉冲电沉积和超声辅助脉冲电沉积制备Ni-CeO2纳米复合镀层,研究电沉积方式对纳米复合镀层表面形貌、显微硬度和摩擦磨损性能的影响,并用扫描电子显微镜分析其磨损机理。结果表明:电沉积方式对Ni-CeO2纳米复合镀层的晶粒尺寸和性能有较大影响;当超声波引入脉冲电沉积过程时,超声波的强力搅拌作用和超声空化效应能促进CeO2纳米颗粒在镀层中均匀分布,进一步减小镀层的晶粒尺寸,明显提高镀层的显微硬度,从而改善镀层的摩擦磨损性能;Ni-CeO2纳米复合镀层的摩擦磨损性能均优于纯Ni镀层的;而超声辅助脉冲电沉积制备的Ni-CeO2纳米复合镀层的晶粒更加细小、显微硬度最高,其摩擦因数最低,耐磨损性能最佳。

The Ni-CeO2 nanocomposite coatings were fabricated by direct current electrodeposition,pulse current electrodeposition and ultrasonic-assisted pulse electrodeposition.The effects of electrodeposition methods on the surface morphology,microhardness as well as friction and wear properties of the Ni-CeO2 nanocomposite coatings were investigated.The wear mechanism of the nanocomposite coatings was analyzed using a scanning electron microscope（SEM）.The results show that the electrodeposition methods can markedly affect the grain sizes and the properties of Ni-CeO2 nanocomposite coatings.While the ultrasound is introduced in the pulse electrodeposition process,the strong stirring action and the cavitating effect of ultrasound not only promot the uniform distribution of CeO2 nanoparticles in the coatings,but also reduce the grain sizes further,which leads to the enhancement of the microhardness of the coatings and then improves the friction and wear properties of the coatings.The friction and wear properties of the Ni-CeO2 nanocomposite coatings are better than those of the pure Ni coating.The Ni-CeO2 nanocomposite coatings prepared by ultrasonic-assisted pulse electrodeposition,which possess finer grains and highest microhardness,exhibit the lowest friction coefficient and the best wear-resistance.