镁合金直接化学镀镍工艺及镀层性能

摘要

The optimal process conditions for direct electroless nickel plating on AZ31D magnesium alloy are as follows: nickel sulfate 14-22 g/L, sodium hypophosphite 20-28 g/L, citric acid 5-7 g/L, sodium acetate 9-17 g/L,ammonium hydrogen fluoride 8 g/L, hydrofluoric acid (volume fraction 40％) 12 mL/L, thiourea 2 mg/L, pH 6.2-6.4(adjusted with ammonia water), temperature 75-85 ℃ and deposition time 10-60 min. Under the given conditions, the deposit has the features of good appearance, strong adhesion to magnesium alloy substrate, high corrosion resistance, phosphorus content of 6％-10％ and fast deposition rate.%AZ31D镁合金上直接化学镀镍的较佳工艺条件为:硫酸镍14～22g/L,次磷酸钠20～28 g/L,柠檬酸5～7 g/L,乙酸钠9～17 g/L,氟化氢铵8 g/L,40%(体积分数)的氢氟酸12 mL/L,硫脲2 mg/L,pH(用氨水调节)6.2～6.4,温度75～85℃,时间10～60 min.在此条件下获得的化学镀镍层外观良好,磷含量为6%～10%(质量分数),与镁合金基体结合牢固,耐蚀性能好且沉积速率较快.