锌镍合金镀层耐蚀性的研究

MECHANISM OF CORROSION RESISTANCE OF Zn—Ni ALLOY PLATING

用X射线衍射(XRD),X光电子能谱(XPS),离子探针(IMA)和俄歇电子能谱(AES)等测试方法对锌镍合金镀层及其腐蚀产物进行了分析。锌镍合金镀层的晶体结构和耐蚀性随合金成份的变化而变化,当镀层中镍含量为13wt％左右时,耐蚀性最佳。探讨了锌镍合金镀层的微观结构与耐蚀性的关系以及锌镍合金镀层具有高耐蚀性的原因,并讨论了锌镍合金镀层的腐蚀机理。

The corrosion mechanism of Zn-Ni alloy coating has been investigated. The composition, distribution and chemical states of the alloy coating and corrosion products have been measured by means of X-ray diffraction, Auger Electro Spectroscopy, X-ray photoelectron spectroscopy and Ion Microanalysis. The Zn-Ni alloy plating containing about 13％(wt) Ni has the best corrosion resistance in salt spray test. The structure of the alloy with about 13％ Ni is γ phase and has the composition of NiZn_3 or Ni_5Zn_(21).The main corrosion product of 13％ Ni alloy deposit is ZnCl_2·4Zn(OH)_2 which can restrain the corrosion process.