Process Improvement of Normal Temperature Phosphating Solution

Orthogonal test was used to optimize the phosphating solution at 40 ℃. The results showed that when the solution composition was zinc oxide 15 g/L, zinc dihydrogen phosphate 12 g/L, phosphoric acid 25 ml/L, sodium fluoride 0.6 g/L, potassium chlorate 0.3 g/L, citric acid 0.2 g/L, urotropine 0.25 g/L, sodium molybdate 0.18 g/L, SDBS 0.18 g/L, zinc phosphate 3.5 g/L, 50% manganous nitrate 3.5 g/L, the average time of copper sulfate drip of the prepared film was 78 s and the average value of the phosphating solution acid ratio was 23.8. The reaction temperature and the amount for manganese ions of the phosphating solution are lower than that of other phosphating process. The improved process is an economical, green and environmental process route.