热镀锌板表面钝化时的磷化工艺

热镀锌板表面钝化（铬酸盐钝化），主要是为了防止在使用过程中其表面被氧化。由于表面的钝化膜的存在。使得磷化工艺无法进行，从而影响涂装后涂层的附着力（铬酸盐钝化膜不如磷化膜附着性好）和耐蚀性能（铬离子不耐氯离子的腐蚀）。为了提高热镀锌板表面钝化后其表面的涂装性能，开发出一种适合上述条件的磷化工艺。

Phosphatizing Technique for Passivated Surface of Hot Galvanized Steel Plate

Surface passivation by chromate for the hot dip galvanized plate is applied to prevent the surface oxidation during the process time. However, the phosphatization technics can not be processed due to the existing of passivating film on the surface, therefore both the adhesive force and the erosion resistance are affected because the adhesive force of chromate passivating film is not as strong as the phosphatizing film and chlorine ion can erode the chrome ion. In order to improve the performance of the painting on the passivation surface of the hot galvanized plate, we developed one phosphatizing technics that can be adapted to above conditions.