ABSTRACT

Previously, the authors developed a stable citrate ethylene glycol (EG) electrolyte providing the electrodeposition of Ni–Sn alloy at quite high rate, current efficiency and nickel content in the alloy. In this study a complexation in the solution containing nickel and tin(II) chlorides, and citric acid was studied. IR spectroscopy data have shown the availability of Ni(EG)₂Cl₂ and Sn(EG)Cl₂ complex compounds in the EG solution. At the addition of citric acid complexation of Ni(II) and Sn(II) with dihydrocitrate ions occurs. Binding of Sn(II) ions into complex compounds like Sn(EG)(H₂Cit)₂ promotes regulation of Ni(II) and Sn(II) reduction rates, and ensures the increased nickel quota in the alloy and the stability of electrolyte against Sn(II) to Sn(IV) oxidation. The rate of coating deposition strongly depends on the electrical conductivity of the EG solution and rises with an increase in the temperature and concentration of metal halide crystalline hydrates.

摘要

此前，作者开发了一种稳定的柠檬酸乙二醇 (EG) 电解质，以相当高的速率、电流效率和合金中的镍含量提供 Ni-Sn 合金的电沉积。在这项研究中，研究了含有氯化镍和氯化锡 (II) 以及柠檬酸的溶液中的络合。IR 光谱数据表明 EG 溶液中存在 Ni(EG) ₂ Cl ₂和 Sn(EG)Cl ₂复合化合物。在添加柠檬酸时，发生 Ni(II) 和 Sn(II) 与二氢柠檬酸根离子的络合。将 Sn(II) 离子结合成复杂的化合物，如 Sn(EG)(H ₂ Cit) ₂促进 Ni(II) 和 Sn(II) 还原率的调节，并确保合金中镍配额的增加和电解液对 Sn(II) 到 Sn(IV) 氧化的稳定性。涂层沉积速率很大程度上取决于 EG 溶液的电导率，并随着温度和金属卤化物结晶水合物浓度的增加而升高。