Cr颗粒浓度对车轴上电沉积石墨增强Ni基涂层结构的影响

Effect of Cr Particle Concentration onStructure of Ni-based Protective Coating Enhanced by Electrodeposited Graphite on Axle

在电沉积Ni-C过程中添加不同浓度含量Cr颗粒得到Ni-Cr-C保护涂层,分析了Cr颗粒浓度对Ni-Cr-C保护涂层性能的优化效果,测定了涂层表面硬度。结果表明:形成了较平滑的Ni-C涂层,大部分区域呈现规则多边形形态。添加Cr颗粒后,表面区域形成了一些无规则外形的结节状组织,产生了大量孔隙。逐渐提高Cr颗粒量后,在涂层表面形成了尺寸更小的孔隙。当Cr颗粒的含量提高后,在涂层内形成了不同最高强度的Ni衍射峰,从原先的(110)晶面转变成(101)晶面。当Cr颗粒含量提高后,形成了更小Ni晶粒,加入80 g/L的Cr颗粒时Ni晶粒外径尺寸为29.2 nm。可通过加入Cr颗粒来制备硬度更高的涂层;且随Cr含量提高,沉积层的硬度也随之上升。更高含量的Cr颗粒(80 g/L)时,Ni-Cr-C层获得了更高的硬度551 HV。

The protective coating of Ni-Cr-C was obtained by adding Cr particles with different concentrations in the electrodeposition process of Ni-C.The optimization effect of Cr particle concentration on the performance of protective coating of Ni-Cr-C was analyzed,and the surface hardness of the coating was measured.The results show that the smooth Ni-C coating is formed,and most areas are in regular polygon shape.After Cr particles are added,some random nodular microstructure is formed in the surface area,and a large number of pores are generated.After increasing the Cr particle size gradually,smaller pores are formed on the coating surface.When the content of Cr particles increase,Ni diffraction peaks with different highest intensities are formed in the coating,which changes from the original(110)crystal plane to(101)crystal plane.When the Cr content increases,smaller Ni grains are formed,and the outer diameter of Ni grains reaches 29.2 nm with the addition of 80 g/L Cr particles.Stricter coatings can be prepared by adding Cr particles,and the hardness of the deposited layer increases with the increase of Cr content.The hardness of Ni-Cr-C layer is 551 HV when the content of Cr particles is higher.