Co和P对Ni-金刚石复合电沉积机理的影响

Effect of Co and P on mechanism of Ni-diamond composites electro-deposition

在电镀液中添加金刚石微粉,采用复合电镀方法可以制备Ni-金刚石复合镀层,为了研究元素添加对复合镀层工艺的影响,采用电化学方法研究Ni-金刚石复合电沉积机理,分析Co、P元素的加入对复合电沉积过程的影响规律.结果表明:通过循环伏安与动电位极化分析,Co或Co、P的共同加入使得复合电沉积过程中沉积电位正移,说明其可降低阴极表面Ni结晶的驱动力,促进金属的沉积.通过电化学阻抗分析,表明随着Co和P的加入,阴极沉积过程出现2个时间常数,说明阴极沉积反应分2步进行,Co比Ni优先在阴极沉积,并且Ni-Co-P-金刚石复合镀层具有较小的电荷转移电阻,说明Co和P的加入可促进阴极电沉积速率.

The Ni-diamond composite coating can be obtained by the electro-deposition with the diamond particles added in electrolyte. To obtain the rapid fabrication method of Ni-diamond composite coating, the electrochemical method was used to investigate the mechanism of Ni-diamond electro-deposition. The effect of Co and P addition on electro-deposition process of Ni-diamond was studied. The results show that, by analyzing the cyclic voltammetry, the electro-deposition potential of Ni-diamond become positive with the addition of Co or Co and P, which means the crystallization drive force of nickel is decreased and the deposition of nickel is improved. By the electrochemical impedance spectroscopy analyzing, the deposition process of cathode presents two time constants. The cathodic deposition reaction is carried out in two steps,and the Co is deposited before the Ni deposition. Then, the transfer resistance of Ni-Co-P is smaller. The deposition rate is enhanced by the Co and P addition.