电泳涂装常温磷化工艺及磷化膜的耐碱性研究

Room Temperature Phosphating Technology for Electro-phoretic Coating and Alkaliproof Performance of the Phosphating Film

在自制的低温锌系磷化液基础上,通过加入镍盐、锰盐和羧基聚合物,并以硝基苊为促进剂,研制出了一种适用于电泳涂装的低镍、低锌锰改性常温磷化工艺,获得了其最佳工艺参数为:2.6g/L Zn2+,12.0g/L PO43-,4.0g/L NO3-,2.1g/L羧酸化合物,1.0g/L Ni2+,5.0g/L Mn2+,2.5g/L硝基苊,10.0g/L羧基聚合物,磷化时间10min。试验结果表明:该磷化工艺在常温下可在10min内在金属表面形成一层完整、致密、耐碱性好、抗蚀性强的椭球状磷酸盐晶体薄膜。

Nickel salt,manganese salt,carboxyl-containing polymer,and nitro-acenaphthene accelerating agent were introduced in low-temperature Zn-system phosphating bath to develop a new phosphating technology characterized by low content of Ni,Zn and Mn and suitable to electro-phoretic coating.The optimized phosphating bath composition was determined as 2.6 g/L Zn2+,12.0 g/L PO43-,4.0 g/L NO3-,2.1 g/L carboxylic acid,1.0 g/L Ni2+,5.0 g/L Mn2+,2.5 g/L nitro acenaphthene,and 10.0 g/L carboxyl-containing polymer,while the phosphating duration was suggested as 10 min.Moreover,the alkaliproof performance of the phosphating film was evaluated.It was found that the modified phosphating process could be used to prepare compact phosphating film on metal surfaces at ambient temperature,and the resulting phosphating film had good alkaliproof performance and corrosion resistance as well.