Research on Effect of Rare Earth Compounds in Phosphating Process

The effect of REC on appearance, weight and coating corrosion resistance was discussed, of which results suggest that addition of a small quantity of the REC into phosphating bath is very advantageous in terms of coating resistance to corrosion and depositing speed, and the scale of optimizing doses of REC added in bath is 30 ～ 55 mg ·L -1.Through analyses of configurations and components of films by SEM and EDS, it was ascertained that the samples gained in bath added REC, relative to the sample got in bath without REC, improve the coating inoxidizability because of increasing of covering rate of sheet crystals in the surface, and the sequence of what elements P, Fe and Zn contribute to erosion resistance of films is Fe ＞ P ＞ Zn.