用极谱法、电势扫描法以及电解法研究了铁系镀液中抗坏血酸的作用机理。实验结果表明:抗坏血酸可把Fe~(3+)离子还原成Fe~(2+)离子,可把溶液中溶解氧减少至微量。抗坏血酸的氧化产物可用电解法使之还原,变成抗坏血酸。因此,铁系镀液中的抗坏血酸可以保持在一个恒定值,从而有效地防止了Fe~(2+)离子的氧化。 The action mechanism of ascorbic acid in iron-based bath was studied by polarography, potentiometric scanning and electrolysis. The experimental results show that ascorbic acid can reduce Fe 3+ ions to Fe 2+ ions and reduce the dissolved oxygen in the solution to trace amount. The oxidation products of ascorbic acid can be electrolytically reduced to become ascorbic acid. Therefore, ascorbic acid in the iron-based plating solution can be kept at a constant value, thereby effectively preventing the oxidation of Fe 2+ ions.