硼砂对电镀铜-镍合金耐蚀性的影响

Effect of borax on corrosion resistance of electroplated copper-nickel alloy coating

在Cu-Ni合金电镀液(由NiSO_(4)·6H_(2)O 174 g/L、CuSO_(4)·5H_(2)O 16 g/L、Na_(3)C6H5O_(7)·2H_(2)O 87 g/L和CH_(3)COONa 10 g/L组成)中添加0~5 g/L硼砂(Na_(2)B_(4)O_(7)·10H_(2)O),对比了硼砂质量浓度不同时铜基材上所得Cu-Ni合金镀层的外观、厚度和表面形貌。通过电化学阻抗谱(EIS)和Tafel曲线测试研究了硼砂质量浓度对电镀Cu-Ni合金耐蚀性的影响。结果表明,镀液中添加1~5 g/L硼砂对沉积速率影响不大,但能够提高Cu-Ni合金镀层的均匀性、致密性和平整性,进而改善其耐蚀性。随电镀液中硼砂质量浓度增大,Cu-Ni合金镀层的耐蚀性先改善后变差。当硼砂质量浓度为3 g/L时,Cu-Ni合金镀层的表面形貌最佳,耐蚀性最好。

The electroplating of Cu-Ni alloy was conducted with copper as substrate in a bath composed of NiSO_(4)·6H_(2)O 174 g/L,CuSO_(4)·5H_(2)O 16 g/L,Na_(3)C_(6)H_(5)O_(7)·2H_(2)O 87 g/L,CH_(3)COONa 10 g/L and borax(Na_(2)B_(4)O_(7)·10H_(2)O)0-5 g/L.The appearance,thicknesses,and surface morphologies of the Cu-Ni alloy coatings electrodeposited with different mass concentrations of borax were compared.The effect of the mass concentration of borax on the corrosion resistance of Cu-Ni alloy coating was studied by electrochemical impedance spectroscopy(EIS)and Tafel curve measurement.The results showed that the addition of 1-5 g/L of borax to the electroplating bath slightly affected the deposition rate of Cu-Ni alloy coating,but improved its uniformity,compactness,and smoothness,resulting in a better corrosion resistance.The corrosion resistance of Cu-Ni alloy coating was improved initially and then deteriorated with the increasing of the mass concentration of borax.The Cu-Ni alloy coating electrodeposited with 3 g/L of borax had the best surface morphology and corrosion resistance.