Study On Corrosion Resistance Of Decorative Satin Nickel Plating

Conductive plastic plating has a wide range of applications in the automotive,optical instruments and other industrial fields and can replace a variety of metalproducts. Satin nickel plating can improve the dazzling glare of traditional brightnickel plating by adjusting the dosage of satin additive in electroplating solution,resulting in varying degrees of "matte", in order to meet the requirements of industrialapplications of the low-gloss. In the future satin nickel will become the trends ofelectroplating decoration market. At present, the research in low-gloss or matte nickelplating is more focusing on stabilize the emulsification of satin additive andimprovement of plating appearance performance.This study examined the corrosion resistance of satin nickel plating onconductive plastic. The electrochemical tests were to analyze the impact of glossinessand chroma and the corrosion behavior of satin nickel plating with different processesin3.5%NaCl solution. The results show that, because the satin nickel plating has anorganic film on its surface due to process characteristics, the film results in differentcorrosion resistance. By increasing satin additive concentration dosage, the nickelplating chroma decreases, the micro-surface of the plating becomes rough, and thecorrosion resistance is followed by decrease.At the same time, the subject carried on electrochemical analysis of multilayernickel satin nickel plus trivalent chromium plating system, and compared with thetraditional bright nickel plating. Studies showed that the decorative trivalent chromiumcan enhance the corrosion resistance of the satin nickel plating, but EIS results showedonce additive dosage up to0.4ml/L or above, although the glossiness reached100°oreven lower, but the corrosion resistance will decrease. When the satin additive dosagereaches0.6ml/L, protection of chrome plating becomes very weak; the polarizationcurrent density has no decrease compared to the plating without chrome.The subject also studies different protection treatment processes to improve thecorrosion resistance of low-gloss coating, including water repellents, sealer andelectrolytic passivation, etc. Studies showed that electrolytic passivation can improvethe corrosion resistance of plating. Taking additive0.6ml/L sample as example, afterthe process, the study showed its corrosion resistance becomes equivalent to additive 0.4ml/L without protection treatment.