缓蚀剂对镁合金化学镀镍的影响

目的寻找有效抑制镁合金腐蚀的缓蚀剂,提高镀层质量。方法研究缓蚀剂的种类和用量对缓解镁合金腐蚀的影响,研究不同缓蚀剂对化学镀镍层的影响。采用全浸失重实验对缓蚀剂的性能进行评价,并通过扫描电子显微镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)和电化学测试对不同缓蚀剂下所得镀镍层的性能进行表征。结果经过初步筛选,六次甲基四胺(Hexamethylenetetramine)、氟化胺(NH_4F)、氟化氢铵(NH_4HF_2)缓蚀剂的效果较明显。AZ9l D镁合金在腐蚀溶液中,随着添加六次甲基四胺浓度的增加,腐蚀速率先减小后增加。随着添加氟化铵、氟化氢铵浓度的增加,腐蚀速率逐渐减小。添加缓蚀剂的体系中较不加缓蚀剂的体系中测得的电化学曲线好。六次甲基四胺、氟化铵、氟化氢铵效果最好时,质量分数分别为1%、1.5%、2%。不同种类缓蚀剂均可以有效抑制镁合金的腐蚀,减小腐蚀电流。加入缓蚀剂的化学镀镍配方沉积和镀覆效果明显,镀层电化学性能也有很大的提升。结论六次甲基四胺(Hexamethylenetetramine)、氟化胺(NH_4F)、氟化氢铵(NH_4HF_2)缓蚀剂的使用可以有效抑制镁合金的腐蚀,提高化学镀镍层的质量。

Effect of Corrosion Inhibitor on Electroless Nickel Plating on Magnesium Alloy

The work aims to look for corrosion inhibitors that effectively inhibit magnesium alloy corrosion and improve the quality of coating. Effects of corrosion inhibitors in different types and amounts on inhibiting corrosion of magnesium alloy and effects of different corrosion inhibitors on electroless nickel plating were studied. The performance of the corrosion inhibitor was evaluated by total immersion and weight loss test and the properties of nickel coatings with different corrosion inhibitors were characterized by scanning electron microscopy (SEM), energy disperse spectroscopy (EDS), X-ray diffractometer (XRD) and electrochemical tests. After a preliminary screening, the effects of hexamethylenetetramine, NH4F and NH4HF2 are more obvious. The corrosion rate of AZ9lD magnesium alloy firstly decreased and then increased with the addition of hexamethylenetetramine concentration in the corrosion solution. With the addition of NH4F and NH4HF2, the corrosion rate decreased gradually. The electrochemical curve measured in the system after addition of corrosion inhibitor was lower than that of the system without corrosion inhibitor. The effects of hexamethylenetetramine, NH4F and NH4HF2 reached the best at mass fraction at 1%, 1.5%, 2% respectively. All inhibitors regardless of type could effectively inhibit the corrosion of magnesium alloys and reduce the corrosion current. The deposition and plating effect of electroless nickel plating added with corrosion inhibitors was obvious and the electrochemical performance also improved greatly. Hexamethylenetetramine, NH4F, NH4HF2 corrosion inhibitor can effectively inhibit the corrosion of magnesium alloys and improve the quality of electroless nickel plating.