Ni-金刚石复合镀层的制备

摘要

The Ni-diamond composite electrodeposition was prepared by composite electroplating when diamond particles with a diameter of 40 μm were put into the solution ofNi electroplating.The effects of temperature,pH value of solution,concentration of Ni2+,cathode current density and concentration of diamond particles on the quality of Ni-diamond composite coatings were investigated by the cathodic potentiodynamic polarization,SEM and microhardness tester.The optimized technological conditions of Ni-diamond composite electrodeposition were obtained.The structure of optimized Ni-diamond composite coating was tested by XRD.The experimental results show that the optimized technological conditions are:NiSO4·6H2O,132 g/L; NiCl2,15 g/L; H3BO3,30 g/L; temperature,(50±1) ℃; pH,3-4;cathode current density,4 A/dm2; concentration of diamond particles,30 g/L.The results of SEM indicate that the surface of the Ni-diamond composite coating containing 62.7％ diamond particles is neat,and small homogeneous grains are obtained.In comparison with pure Ni coating,the grains of the Ni-diamond composite coating are obviously refined.%通过复合电镀方法,在镀镍液中加入粒径为40 μm的金刚石粉体制备Ni-金刚石复合镀层.采用阴极动电位极化方法、扫描电镜和显微硬度计探讨镀液温度、pH、镍离子浓度、电流密度和金刚石粉体质量浓度对镀层质量的影响,优化Ni-金刚石复合镀的工艺参数；采用X线衍射分析仪表征优化后复合镀层的结构.研究结果表明:优化的镀液组成和工艺参数为:NiSO4·6H2O 132 g/L,NiCl2 15 g/L,H3BO3 30 g/L,镀液温度(50±1)℃,pH 3～4,阴极电流密度4 A/dm2,金刚石粉体质量浓度30 g/L;优化后的复合镀层表面平整,晶粒细小均匀,且金刚石粉体的质量分数为62.7％；与纯Ni镀层的晶粒相比,Ni-金刚石复合镀层的晶粒明显细化.