目的 将Al2O3/Ni纳米复合电刷镀技术应用到失效凸轮轴修复，使失效凸轮轴得以再制造利用。方法 在快速镍镀液中加入Al2O3纳米颗粒和分散剂柠檬酸三铵、十六烷基三甲基溴化铵形成复合镀液，将复合镀液放在恒温磁力搅拌器上加热并搅拌，使复合镀液温度达到50 ℃且纳米Al2O3悬浮稳定。利用电刷镀技术将复合镀液镀于与凸轮轴材质相同的45#钢板表面，通过硬度测试，分别评价纳米Al2O3质量浓度、刷镀电压对复合镀层硬度的影响。结果 复合镀层的硬度大于45#钢，且硬度随刷镀电压、纳米Al2O3质量浓度的增加而增加。当刷镀电压大于10 V后，硬度随纳米Al2O3质量浓度的增加而减小。复合镀层表面裂纹随纳米Al2O3质量浓度、刷镀电压的增加而增多，纳米Al2O3的质量浓度越低，电压变化对复合镀层表面硬度的影响越大。相对纳米Al2O3质量浓度，电压对复合镀层表面硬度的影响更大。结论 用Al2O3/Ni纳米复合电刷镀技术修复失效凸轮轴可提高凸轮轴表面硬度，使其得以再制造利用。为提高凸轮轴表面质量，避免出现表面疏松、焦糊等缺陷影响表面硬度，应开发自动化纳米复合电刷镀设备及采用不同镀层交替叠加方式刷镀。

The work aims to apply Al2O3/Ni nano composite brush electro-plating technology to repair and remanufacturing of damaged engine camshaft. Composite plating solution was obtained by adding nano Al2O3 power and dispersants including triammonium citrate and cetyltrimethylammonium bromide into high speed nickel-plating solution. Then the composite plating solution was heated and stirred on a constant temperature magnetic stirrer until the temperature of composite plating solution reached 50 ℃ and Al2O3 nano powers suspended steadily. The brush electro-plating technology was adopted to coat the composite plating solution on the surface of 45# steel plate made from materials identical to those of engine camshaft. The influences of brush plating voltage and mass concentration of Al2O3 nano power on surface morphology and surface hardness of the composite coating were evaluated based upon surface observation and hardness test, respectively. Hardness of the composite coating was higher than that of 45# steel, and surface hardness increased with the increase of brush plating voltage and concentration of Al2O3 nano power. As the plating voltage was over 10 V, surface hardness decreased with the increase of concentration of Al2O3 nano power increased. Surface cracks of the composite coating increased with the increase of the brush plating voltage and concentration of Al2O3 nano power. The lower the concentration of Al2O3 nano power was, the greater the influence of brush plating voltage on surface hardness of the composite coating was. The influence of the brush plating voltage on the surface hardness of the composite coatings was greater than that of mass concentration of Al2O3 nano power. Surface hardness of the camshaft can be improved by applying the Al2O3/Ni nano composite brush electro-plating technology to repair damaged camshafts. In order to improve the surface quality of camshafts and prevent surface defects such as surface porosity and coke paste from affecting surface hardness, automatic nano brush electro-plating plating equipment should be developed, and the plating process in different coating alternatively overlay method shall be adopted.