碱性锌-钴合金镀液中锌、钴含量的测定

Determination of zinc and cobalt content in alkaline zinc-cobalt alloy plating bath

为获得耐蚀性良好的锌 钴合金镀层 ,必须维持镀液中的锌 钴含量在工艺范围内。采用EDTA滴定和分光光度相结合的方法测定碱性锌 钴合金镀液中的锌、钴含量。介绍了该方法的分析步骤 ,探讨了测量波长的确定 ,亚硝酸钠、镀液共存组分、酸度以及铜离子和铁离子等杂质对测量结果的影响。结果表明 ,在 530nm波长下 ,钴浓度在 0 - 3μg/mL范围内所测吸光度与钴浓度间的关系遵守比耳定律 ,该方法准确度高 ,回收率达 97% - 1 0 3 5%。

Zinc and cobalt content in zinc cobalt alloy plating bath should be maintained in a suitable range so that corrosion resistant zinc cobalt alloy deposit can be obtained. Zinc and cobalt content in zinc cobalt alloy plating bath are determined by the combined method of titration with EDTA and spectrophotometry. Measuring procedures were described in detail. Measuring wave length was optimized by experiments. The effects of sodium nitrite, co existing bath components, acidity, impurities such as cupric ions and ferric ions on the measured absorbance were studied. Results show that the measured absorbance to cobalt content curve follows Beer's Law under 530 nms measuring wave length and cobalt content of 0-3 μg/mL. This method has high accuracy with recovery of 97 %-103 5 %.