LAZ900镁锂合金化学镀镍前处理工艺

为了优化镁锂合金化学镀镍前处理工艺,采用磷酸、硝酸和磷酸+硝酸混合溶液3种工艺对镁锂合金进行酸洗,采用氢氟酸、氟化氢铵和磷酸+氟化氢铵混合溶液3种工艺对镁锂合金进行活化,并对活化后的镁锂合金进行镀镍处理。使用金相显微镜、扫描电子显微镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)对处理后试样进行表面分析。结果表明:经硝酸+磷酸混合处理的试样表面氧化皮去除完整、有光泽,3种工艺活化后的试样表面均有氟化镁膜生成,经氟化氢铵活化后的试样表面制得的镍磷合金颗粒均匀,排列致密。最优前处理工艺为:酸洗H3PO42mL/L,HNO310mL/L,NaF 1g/L,室温浸蚀5~30s;活化NH4HF220g/L,室温活化1~3min。

Pretreatment for Electroless Nickel Planting on LAZ900 Mg-Li Alloy

To find a better way of pretreatment for electroless nickel planting on MgLi alloy. MgLi alloy was pickled by using three different processes: phosphoric acid solution, nitric acid solution, phosphoric acid, and nitric acid solution. MgLi alloy was activated by using three different processes: hydrofluoric acid, ammonium hydrogen fluoride solution, and phosphoric acid and Ammonium hydrogen fluoride solution. Electroless nickel planting on MgLi alloy has been finished after different activations. The specimen was analyzed after activation and after nickel plating using metallurgical microscope, SEM, EDS and XRD. The results show that the oxide layer on the surface of MgLi alloy has been completely dismissed during pickling by phosphoric acid and nitric acid solution, and the surface is glossy. A layer of magnesium fluoride is formed on the surface of the sample after each activation process. The nickelphosphorus alloy coating is formed, and the particles are uniform and arrange tight. The best process of pretreatment is phosphoric acid 2 mL/L, nitric acid solution 10 mL/L, sodium fluoride 1 g/L, and 530 s at room temperature for pickling; ammonium hydrogen fluoride 20 g/L, 13 min at room temperature for activation.