铝合金磷化工艺探讨

The Process Discussion on Phosphatization of Aluminum Alloy

为了开发一种适用于工业化的铝合金磷化技术,通过单因素实验研究磷化液各组分含量对磷化膜耐蚀性能的影响,通过正交试验确定磷化液最佳配方,并对工艺参数进行优选。确定磷化液最佳配方及工艺条件为:30 m L/L磷酸,10 m L/L硝酸,12 g/L氧化锌,1.8 g/L氟化钠,1.4 g/L硫酸亚铁,0.6 g/L硝酸镍,2.0 g/L柠檬酸。游离酸度1.0~1.4点,磷化θ为45~55℃,t为6~10 min。结果表明,制备的磷化膜外观均匀致密,呈浅灰至灰色,平均耐硫酸铜点滴t为122 s,膜质量为4.7 g/m^2,耐蚀性能较好。磷化后进行喷漆处理,漆膜耐中性盐雾t为168 h,耐湿热试验大于48 h,磷化膜层与漆膜配套性较好。

In order to develop a appropriate phosphating solution for aluminum alloy,effects of components content of phosphating solution on corrosion resistance of phosphating film were investigated by single factor experiment,the optimum formula was determined by orthogonal test,and the process parameters were optimized. The optimum formula and technological conditions of phosphating solution are as follows： phosphoric acid is 30 m L / L,nitric acid is 10 m L / L,zinc oxide is 12 g / L,sodium fluoride is 1. 8 g / L,ferrous sulfate is 1. 4 g / L,nickel nitrate is 0. 6 g / L,citric acid is 2. 0 g / L,free acidity is 1. 0 ～ 1. 4,temperature is45 ～ 55 ℃ and time is 6 ～ 10 min. The results showed that the phosphate film possessed uniform,compact and light grey surface,tolerance of the phosphate film to copper sulfate drop time was 122 s,film mass was4. 7 g / m2,and the corrosion resistance of the film was excellent. With spray painting treatment after phosphating,resistance of the film to neutral salt spray time was 168 s,to damp heat test time was more than48 h,phosphating film layer and paint film showed good compatibility.