常温高效硫酸盐三价铬电镀工艺

六价铬电镀工艺严重污染环境,有望被三价铬电镀取代.三价铬电镀分为氯化物体系和硫酸盐体系,其中硫酸盐体系因具有阳极无有害气体析出、不腐蚀设备等优点,近年来发展迅速.通过大量试验开发出常温甲酸-草酸体系硫酸盐工艺,并借助小槽挂镀、Tafel曲线、EIS曲线和CASS试验等方法对镀液和镀层性能进行了分析.结果表明,在优化工艺条件下,该工艺镀层沉积速率高达0.18μm/min以上,分散能力93%,覆盖能力96%,耐蚀性好,是一种性能优良、高效的三价铬电镀工艺.

Technology for Efficient Chromium Electroplating at Ambient Temperature in Trivalent Chromium Sulfate Bath

The technology for trivalent chromium electroplating at ambient temperature in a sulfate bath containing formate-oxalate oomplexing agents was established based on a series of screening tests. The properties of the plating bath and Cr coating as well were analyzed by making use of suspended plating in a small cell, measurement of Tafel curve and electrochemical impedance spectra, and corrosion-accelerating salt-spraying (CASS) test. Results indicate that a deposition rate of 0. 18 μm/min, a throw power of 93% and a cover power of 96 % are obtained under optimized plating conditions. And the resulting Cr coating had good corrosion resistance, indicating that the established technology might be used for high efficient electroplating of trivalent Cr.