低污染中温锌系磷化的研究

Study on the low-polluting zinc phosphating process at med-temperature

以硫酸铜点蚀试验作为评定磷化膜耐蚀性的依据,开发了一种高耐蚀性、低污染的中温锌系磷化液的配方及应用工艺。对不含亚硝酸盐促进剂的低污染磷化液进行研究,用自制促进剂A来替代亚硝酸钠,对磷化液组成和使用工艺进行了探讨。通过条件实验得到磷化液的最佳配比:硝酸镍质量浓度为20 g/L,氧化锌质量浓度为35 g/L,硝酸体积分数为4%,磷酸体积分数为3.8%。该磷化液的最佳使用条件:磷化温度为(70±2)℃;磷化时间为10～12 min。扫描电镜显示所得的磷化膜致密、均匀,具有优异的耐蚀性能。

A high corrosion resistance,low-pollution,med-temperature zinc phosphating solution were studied,in which a low-pollution phosphating solution contains the self-accelerating agent A to replace the sodium nitrite.The experiments demonstrate that the best ratio of materials is nickel nitrate 20 g/L,zinc oxide 35 g/L,nitrate 4%,phosphoric acid 3.8%.The best conditions using the phosphating solution were phosphate temperature（70±2） ℃,phosphating time 10-12 min.Phosphating film obtained is compact,uniform,excellent corrosion resistance.