三价铬体系铬-镍合金电镀工艺及镀层性能的研究

Cr-Ni Alloy Electroplating Technology in Trivalent Chromium Bath and Coating Performance

以工业级的革鞣剂和硫酸镍为主盐,研究了硫酸盐体系电镀铬镍合金工艺配方与工艺规范、阴极电流密度、pH值、温度对镀层的影响,讨论了镀层中的铬含量对镀层耐腐蚀性和钎焊性的影响。通过工艺调整使合金中铬质量分数控制在10%～50%。镀层中铬质量分数在10%以下时,镀层有良好的钎焊性。通过测定镀层腐蚀电流,比较其耐腐蚀性,镀层中铬质量分数在25%～40%时,镀层的耐腐蚀性较好,铬质量分数为30%时,腐蚀电流最小可达4.18×10-7A,采用有隔膜电镀槽,提高了镀液的稳定性。

The technological formula and criterion for the chromiumnickel alloy electroplating in a sulfate bath were studied using industrial grade leathertanning agent chromium sulfate and nickel sulfate as the major salts. The influences of cathode current density, pH value, and temperature on the performance of the coating were investigated, while the correlation among the Cr content in the plating and the corrosion resistance and solderability was explored. The corrosion resistance of the CrNi alloy coatings with different compositions was compared by corrosion current measurement. As the results, it was feasible to control the Cr content (mass fraction) in the alloy coating within 10%~50% by properly adjusting the plating parameters. The plating with Cr content below 10% had excellent solderability. The CrNi alloy coating containing 25%~40% Cr had good corrosion resistance, and the coating containing 30% Cr had the lowest corrosion current as much as 4.18×10^(-7)A. Moreover, it was able to increase the stability of the plating bath using membrane.