摘要
通过5 wt%NaCl溶液浸泡腐蚀实验和电化学极化实验测量了热浸锌镀层的腐蚀速率和极化曲线,采用光学显微镜、扫描电镜SEM观察了镀层腐蚀后表面的显微组织,初步探讨了腐蚀机理.研究结果表明:锌浴中加入钴的合金镀层抗腐蚀能力要强于纯锌浴镀层;在盐水腐蚀溶液中,锌镀层能够阻滞腐蚀保护基体的主要原因,是牺牲阳极锌和在镀层表面形成了一层由ZnO和ZnCl2.4Zn(OH)2组成的钝化膜;当锌浴中添加适量钴元素后,在镀层中会形成富钴层,可以阻碍镀层的腐蚀,也有利于稳定腐蚀初期生成的Zn(OH)2或ZnCl2.4Zn(OH)2,降低腐蚀电流,提高镀层的耐腐蚀性能.
The corrosion resistance of the galvanizing coatings was studied by 5 wt% NaC1 solution immersion test and electrochemical polarization. The microstructures of eroded coatings were investigated by means of optical microscopy and SEM. The results shows that Co addition in Zn bath could improve the tarnish resistance of galvanizing coating. In erosive solution, the Zinc coatings protected steels from corrosion mostly by eroding anode zinc first and shaping some surface passivation films of ZnO and ZnC12＂4Zn（OH）2 on the coatings. When Co addition in Zn bath, it formed a Co-rich layer which could play a barrier layer role, on the other hand, Co can stabilify Zn（OH）2 and ZnClE-4Zn（OH）2 which produced in earlier corrosion, and reduce electric current of corrosion. So it improved the tarnish resistance of hot-dipping Zn-Co coating.
出处
《湖南文理学院学报（自然科学版）》
CAS
2012年第2期64-67,72,共5页
Journal of Hunan University of Arts and Science(Science and Technology)
基金
教育部博士点基金(20114301110005)
湘潭大学自然科学研究项目(10XZX15)
关键词
钴
热浸镀锌层
耐腐蚀性
Co
hot-dipping galvanized coating
corrosion resistance
