镍-铁合金镀液中硼酸分析方法的改进

Improvement of Analytical Method of Boric Acid in Ni-Fe Alloy Plating Bath

用传统方法分析镍-铁合金镀液中的硼酸,亚铁离子严重影响测定结果。用亚铁氰化钾沉淀分离镀液中的亚铁离子和镍离子,用甘露醇与硼酸反应生成酸性较强的络合酸,以酚酞作指示剂,用氢氧化钠标准滴定溶液滴定。实验表明,测定结果的平均偏差为0.20%,回收率为98.2%～101.2%。本法准确、简单,优于其它方法。

Ferrous ions have serious influence on the analysis results of boric acid in a Ni-Fe alloy plating bath when the conventional method is used as the analyzing method. In our research, the ferrous ions and nickel ions were first precipitated by utilizing potassium ferrocyanid and separated subsequently, then boric acid was reacted with D-mannitol to produce a complex acid with stronger acidity, and finally, the complex acid was titrated by using sodium hydroxide standard solution with phenothalin as an indicator. Tests showed that the relative average deviation of determination result was 0.20% and recovery was 98.2% ～ 101.2%. This method is accurate,simple,and superior to other methods.