Electroplating Nanostructured Hard Gold through the Pulse Galvanostatic Method

摘要

The present work shows a full study of the pulse electroplating of cobalt hard gold on a nickelsubstrate. Certain parameters in the pulse galvanostatic method, including pulse height (currentamplitude), relaxation time (toff), pulse time (ton) and bath temperature, were effectively optimized bythe 渙ne at a time" method to obtain a suitable nanostructured layer. SEM, XRD, EDS, micro-hardnesstesters, roughness measuring instruments and the Auto Lab electrochemical analyzer were utilized instudying the influence of pulse electrodeposition variables on the surface morphology, particles sizes,film composition, mechanical characteristics and electrochemical behaviors of the deposited layer. Theobtained results indicate that under the optimized conditions for pulse electroplating, the pulse height,-2 the toff, the ton, and the bath temperature are 3 mA.cm , 1.5 s, 0.5 s, and 25 C respectively. Theelectroplated surface in the optimum conditions includes a uniform nanostructured layer with lowporosity and fine grains, with an average diameter of 70 nm which has excellent mechanical andelectrochemical properties such as hardness and anticorrosion.