铝合金表面电沉积Ni-SiC复合镀层的研究

针对铝合金表面的电镀特点,采用化学侵锌、预镀镍等预处理方法,在铝合金表面得到了表面光洁平整,内部质量优良,与铝合金基体结合紧密的Ni-SiC复合镀层。研究了镀液中SiC浓度、电流密度、搅拌速度、镀液pH值和镀液温度等电镀参数对复合镀层厚度、镀层中的SiC体积分数及镀层显微硬度的影响。结果表明,电镀工艺条件的改变影响Ni-SiC复合镀层的共沉积速度与SiC粒子在镀层中的体积分数。当镀液SiC浓度为120g/L时,镀层中的SiC体积分数为8.5％,硬度为504.6HV,较纯铝(82.5HV)提高5倍,较纯镍(242.5.HV)提高l倍。

STUDY ON Ni-SiC COMPOSITES COATING ON THE ALUMINUM ALLOY BY ELECTRO DEPOSITION

Ni-SiC composites coating on the Al alloy with smooth surface, good interior quality and tight combination with substrate is obtained by the pretreatment such as chemical zinc coating and nickel pre-electroplating. The effects of the SiC particle composition of the electrolyte , the current density, the stirring rate, the pH of the electrolyte, the temperature on the volume fraction of SiC deposited in the Ni layer, thickness and hardness of the coating are studied. The results show that these technical variables have remarkable effects on the co-depositing rate of Ni-SiC coating, hardness and the volume fraction of SiC particles. When the SiC particles composition of the electrolyte is 120 g/L, SiC in the coating is 8.5% in volume fraction, and the hardness is 504.6 HV, which is 6 times of pure Al(82.5 HV), 2 times of pure Ni(242.5 HV).