摘要
使用电弧喷涂通过包套挤压+拉拔的方法制备的Zn55Al伪合金丝材在Q235钢上喷涂出了Zn55Al涂层。通过扫描电镜和微区XRD研究了Zn55Al伪合金丝材的显微结构。通过浸泡腐蚀实验和电化学方法研究了Zn55Al涂层、Zn15Al涂层和Al涂层的腐蚀行为,并对比了3种涂层之间的差异。结果表明Zn55Al伪合金丝材由纯锌和纯铝组成,在整个成型过程中没有产生合金化。Zn55Al涂层由层片状的富锌相和富铝相组成。经过20 d的浸泡实验,Zn55Al涂层形成了一层致密的钝化膜,比其他2种涂层有更好的耐腐蚀性。Zn55Al涂层的自腐蚀电位大约是–1.25 V,高于Zn15Al涂层,低于纯Al涂层和Q235基体。电偶腐蚀实验表明,Zn55Al涂层比Zn15Al涂层具有更好的电化学保护作用。这些结果说明Zn55Al涂层具有更好的耐腐蚀性,可以给Q235基体提供更强的电化学保护。本研究也讨论了Zn55Al涂层的的腐蚀机理。
A Zn55Al pseudo-alloy wires with high Al content were prepared by multi-core canned hot extrusion and a cold drawing method, and then they were deposited on Q235 steel by arc spraying to form a Zn55Al coating. The microstructure of the Zn55Al pseudo-alloy wire was investigated by scanning electron microscopy(SEM) and micro-region X-ray diffraction(Micro-XRD). The corrosion behaviours of the Zn55Al coating and pure Al coating as well as the Zn15Al coating were investigated by an immersion corrosion test and electrochemical measurements, and the difference between the coatings was also assessed. The results indicate that Zn55Al pseudo-alloy wires are composed of pure Zn and pure Al. An alloying phenomenon does not occur in the whole formation process. The Zn55Al coating that contains Zn-rich phases and Al-rich phases exhibits an obvious lamellar structure with a few holes and gaps. After 20 d of immersion, it is found that the Zn55Al coating forms a dense passive film and has better corrosion resistance than the Zn15Al coating. The corrosion potential(Ecorr) of the Zn55Al coatings is approximately –1.25 V, which is more positive than that of the Zn15Al coatings but is more negative than that of the pure Al coatings and the Q235 substrate. The results of galvanic corrosion test also shows that the Zn55Al coating can provide better electrochemical protection than Zn15Al coating to the Q235 substrate. This suggests that Zn55Al coating displays not only a better corrosion resistance but also a stronger electrochemical protection to the Q235 substrate. The protective mechanisms of the Zn55Al coating were also discussed.
作者
冯上宾
贾丽娜
张花蕊
王方方
刘光旭
张虎
Feng Shangbin;Jia Lina;Zhang Huarui;Wang Fangfang;Liu Guangxu;Zhang Hu(Beihang University,Beijing 100191,China)
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2019年第4期1087-1095,共9页
Rare Metal Materials and Engineering
基金
National Key Research and Development Program of China(2016YFB0300901)
