镀锌层三价铬钝化膜腐蚀行为的研究  

Corrosion Behavior of Passivation Coatings on Hot-Dipping Galvanized Steel Prepared from Trivalent Chromium Salt

作　　者：任艳萍[1] 陈锦虹[2] 

机构地区：[1]广州民航职业技术学院,广东广州510403 [2]华南理工大学材料学院,广东广州510640

出　　处：《材料保护》2007年第2期7-10,41,共5页Materials Protection

摘　　要：通过盐雾试验、扫描电镜、电化学测试和X射线光电子谱(XPS)等手段,研究了三价铬盐(TC)和三价铬盐加丙烯酸树脂(TCA)两种钝化液制得钝化膜的腐蚀行为及其耐蚀机理。结果表明,热浸镀锌层经TC、TCA钝化处理后,均能有效提高其抗腐蚀能力;SEM发现TC钝化膜表面出现微裂纹,TCA钝化膜表面呈网状的胞状组织覆盖于镀锌层之上,这种致密性好、稳定性高的膜层起到了更好的机械隔离作用,并能抑制钝化膜中微裂纹的产生,所以耐蚀性能大大提高;XPS分析表眀,TC及TCA钝化膜层铬是以CrOOH或Cr(OH)3三价存在。此外,TCA膜层中还含有四价C、五价N。The passivation solutions composed of bivalent chromium salt (TC) and trivalent chromium salt-acrylic resin (TCA) were used to replace toxic chromate passivation solution for the surface modification of hot - dipping galvanized steel. The corrosion behavior ofthe resulting passivation coatings was evaluated using neutral salt -spraying test and electrochemical test, and the anticorrosion mechanism of the passivation coatings was discussed. Moreover, the mi crostructures of the passivation coatings were observed using a scanning electron microscope, while the chemical states of the typical elements in the coatings were analyzed using an X-ray photoe lectron spectroscope. It was found that the corrosion resistance of the hot-dipping galvanized steel was effectively increased after passivation with both TC and TCA solutions, and the TCA passivation coating had similar inhibitive efficiency as chromate passivation coating. Besides, some micro-cracks were observed in the TC passivation coating, but the TCA passivation coating was uniform and compact and showed network - cystiform morphology ascribed to a-crylic resin, which could contribute to greatly increasing the corrosion resistance of the TCA coating. In addition, the chromium in both the TC and TCA coatings existed as trivalent Cr, i. e. , Cr(OH)3 or CrOOH, and quadrivalence C and quinquevalence N were also detected in the TCA passivation coating.

关 键 词：三价铬钝化 丙烯酸树脂 镀锌层 

分 类 号：TG174.44[金属学及工艺—金属表面处理]