一起金镀层脱落质量事故的分析及处理

Analysis and treatment for peeling off problem of gold electroplating coating

因一起金层脱落的质量事故,分析了预镀镍层与镀金层结合力弱的原因。试验发现,镍层钝化和被带入镀金槽中的镍离子的水解产物附着在镍层表面,是造成金层剥离的原因。预镀镍后活化,加强镀金前水洗,以及调整镀金液的pH为4.2～4.5,可保证金层与镍层良好的结合力。

The causes for poor adhesion between nickel pre-plating coating and subsequently plated gold coating were analyzed in view of a quality accident about peeling off of gold coating. It was found through experiments that the peeling of gold coating was caused by the passivation of nickel coating and the adsorption of hydrolysis product of nickel ions dragged into gold plating bath onto the nickel coating. By adding an activation step after nickel pre-plating, improving water rinsing before gold plating, and adjusting the pH of gold plating bath to 4.2-4.5, the adhesion strength between nickel coating and gold coatingcan be guaranteed.