Mechanism of Anomalous Electrodeposition of Fe-Ni
Mechanism of Anomalous Electrodeposition of Fe-Ni
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DOI：
10.4139/sfj.55.428
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
Hiroaki Nakano;S. Oue;Shunsuke Kawano;M. Yano;Shigeo Kobayashi;T. Tsuru;H. Fukushima
中科院分区：
文献类型：
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作者：
Hiroaki Nakano;S. Oue;Shunsuke Kawano;M. Yano;Shigeo Kobayashi;T. Tsuru;H. Fukushima
在pH为1 ~ 3的硫酸液中，在40℃下进行了Fe-Ni合金的电沉积，探讨了其共沉积机理。结果表明：(1)Fe- ni合金的电沉积行为表现出典型的异常共沉积特征，在大多数电镀条件下，电化学性质较低的Fe优先沉积。这种异常共沉积是由于铁的共沉积抑制了Ni的沉积。(2)异常共沉积明显依赖于溶液的pH缓冲能力，这可以解释为在水合铁族金属离子的多步还原过程中，FeOH+和NiOH+的解离常数不同，导致FeOH在沉积位点上的优先吸附。(3)在电镀条件下，降低了低品位铁的优先沉积程度，减少了FeOH在阴极上的吸附。(4)用NaOH溶液在Fe2+单浴中测定pH滴定曲线。Fe2+单浴液在pH 6.3左右表现出pH缓冲作用，对应于由FeOH+解离常数计算的滴定曲线中FeOH+的生成。
Electrodeposition of Fe-Ni alloys was conducted galvanostatically in sulfate baths of pH 1-3 at 40oC to investigate their codeposition mechanism. The results obtained are described as follows : (1) The electrodeposition behavior of Fe-Ni alloy showed a typical feature of anomalous codepostion, in which electrochemically less noble Fe deposits preferentially under most plating conditions. This anomalous codepostion was caused by the suppression of Ni deposition due to codeposition of Fe. (2) The anomalous codeposition was evidently dependent on the pH buffer capacity of the baths, which can be explained in terms of the preferential adsorption of FeOH on the deposition sites due to different dissociation constants between FeOH+ and NiOH+ in the multi-step reduction process of hydrated iron-group metal ions. (3) The degree of the preferential deposition of less noble Fe was decreased under the plating conditions to decrease the adsorption of FeOH on the cathode. (4) The pH titration curves were measured in an Fe2+ single bath using NaOH solution. The Fe2+ -single bath showed pH buffering action around pH 6.3, which corresponds to FeOH+ formation in the titration curve calculated from the dissociation constant of FeOH+.