Molybdate passivation film was prepared on the surface of Zn-5% Al galvanized steel sheet. Effects of bath pH, treatment temperature and time on the film properties were discussed. Corrosion resistance of the passivation film was studied by electrochemical method. Results showed that anodic polarization curve of the passivation film presented in passivation characteristics. Surface morphology of the passivation film was observed by environmental scanning electron (SEM) ,and it was found that the passivation film formed on Zn-5% Al galvanized steel sheet presented in lamellar structure. Composition of the passivation film was analyzed by energy diffraction X-ray (EDX) and result indicated that the passivation film was composed of Mo,P,O,Zn and Al.%在钢板热浸镀Zn-5％Al合金表面制备了钼酸盐钝化膜,探讨了溶液pH、θ及t对钝化膜性能的影响.采用电化学方法对钝化膜耐腐蚀性能进行测试.结果表明,Zn-5％Al合金钝化膜阳极极化曲线呈现钝化特征.用扫描电镜对钝化膜的表面形貌进行观察,发现钝化膜呈片层状结构,用环境扫描电镜配套的能谱仪对钝化膜成分进行分析,结果表明钝化膜由Mo、P、O、Zn和Al等元素组成.
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