实践逼出来的点滴创新 第六部分──镀铬液中三价铬的控制

Some technical innovations inspired from practice Part Ⅵ──Control of trivalent chromium in chromium-plating bath

不同镀铬工艺所允许的三价铬含量上限各不相同,过多均有害。采用传统的小阴极大阳极电解法,费时费料费电。实践发现,采用含锡量为20%左右的铅锡阳极时,三价铬含量有不断下降的趋势。三价铬含量偏低时,根据计算加入适量草酸即可很方便地将其控制在最佳范围内。

The upper limits of Cr（Ⅲ） concentration in different Cr-plating processes are different. Traditional electrolysis with small cathode and large anode has disadvantages of long treatment time, high material consumption and high energy consumption. The content of Cr（Ⅲ） in plating bath is decreased constantly by using Pb-Sn anode containing ca. 20% Sn. The concentration of Cr（Ⅲ） is easily controlled in optimal range by adding a proper amount of oxalic acid when Cr（Ⅲ） content is low.