以镍盐为促进剂,以有机酸为添加剂,在钼酸盐溶液体系中,在热浸镀锌钢板表面制备出黑色钼酸盐化学转化膜。用电化学技术评价了转化膜的耐化学腐蚀性能,确定了最佳制备工艺条件。结果表明:在3.5%NaCl溶液中,转化膜动电位极化曲线阳极分支呈现钝化状态,电化学阻抗谱为单一容抗弧。扫描电镜观察表明,钝化膜均匀致密。EDS分析显示,钝化膜主要由Mo、P、O、Zn、Al等元素组成。
Black molybdate chemical conversion coating was prepared on the surface of hot dip galvanized steel from molybdate bath using nickel salt as accelerator and organic acid as additive.The anti-corrosion performance was estimated by electrochemical techniqe and the optimal preperation condition was determined.The results show that the anodic branch of potentiodynamic polarization curve presented passivation status,and the electrochemical impedance spectrum showed single capacitive impedance arc.Scanning electron microscope observation indicat that the passive film is uniform and compact.EDX analysis exhibits that the film is composed of molybdenum,phosphorus,oxygen,zinc and aluminum.