前处理工艺对AZ31镁合金浸锌层性能的影响

浸锌是镁合金电镀与化学镀之前的重要工艺,浸锌层的质量直接影响电镀层或化学镀层的性能。本工作采用扫描电镜(SEM)、动电位极化曲线等方法研究了酸洗和活化工艺对镁合金浸锌层质量的影响。结果表明,最优的酸洗工艺为:30ml/L 65%HNO3+0.5g/L硫脲,室温,时间20s;最优的活化工艺为:375ml/L HF(40%),室温,时间10min;经优化工艺前处理浸锌后能够得到晶粒细小均匀的浸锌层,而且浸锌层与基体结合良好,耐蚀性优良。

Influence of Pretreatment on Zinc Dipped Coating of AZ91D Magnesium Alloy

Zinc dipping is an important process before electroless platingor electroplating of magnesium.The quality of zinc coating affected the properties of electroless or electroplating coatings directly.The effects of picking and activating processes on the properties of zinc coating were investigated by SEM and potentio-dynamic polarization test.The results show that the best pickling process is pickling 20 s at ambient temperature in 30 ml/L 65% HNO3 + 0.5 g/L thiourea.The best activating process is activating 10 minutes at ambient temperature in HF(40%) 375 ml/L.Fine zinc coating can be obtained in optimization process.The zinc coating combined well with magnesium matrix and had good corrosion resistance.