Effect of Zn/Mg ratio on cathodic protection of carbon steel using Al-Zn-Mg sacrificial anodes  

锌镁比对Al-Zn-Mg牺牲阳极用于碳钢阴极保护的影响

作　　者：Mosaad SADAWY Saad SAAD Randa ABDEL-KARIM Mosaad SADAWY;Saad SAAD;Randa ABDEL-KARIM(Department of Mining and Petroleum Engineering,Faculty of Engineering,Nasr City,Al-Azhar University,Cairo 11371,Egypt;Department of Metallurgy,Faculty of Engineering,Cairo University,Giza 12613,Egypt)

机构地区：[1]Department of Mining and Petroleum Engineering,Faculty of Engineering,Nasr City,Al-Azhar University,Cairo 11371,Egypt [2]Department of Metallurgy,Faculty of Engineering,Cairo University,Giza 12613,Egypt

出　　处：《Transactions of Nonferrous Metals Society of China》2020年第8期2067-2078,共12页中国有色金属学报（英文版）

摘　　要：Al-Zn-Mg alloys with different Zn/Mg mass ratios were evaluated as sacrificial anodes for cathodic protection of carbon steel in 3.5 wt.%Na Cl solution.The anodes were fabricated from pure Al,Zn and Mg metals using casting technique.Optical microscopy,SEM-EDS,XRD and electrochemical techniques were used.The results indicated that with decreasing Zn/Mg mass ratio,the grain size ofα(Al)and the particle size of the precipitates decreased while the volume fraction of the precipitates increased.The anode with Zn/Mg mass ratio>4.0 exhibited the lowest corrosion rate,while the anode with Zn/Mg mass ratio<0.62 gave the highest corrosion rate and provided the highest cathodic protection efficiency for carbon steel(AISI 1018).Furthermore,the results showed that the anode with Zn/Mg mass ratio<0.62 exhibited a porous corrosion product compared to the other anodes.研究不同锌镁质量比的Al-Zn-Mg合金作为牺牲阳极在3.5wt.%Na Cl溶液中用于碳钢阴极保护的性能。用纯Al、Zn和Mg金属通过铸造法制备Al-Zn-Mg阳极。采用光学显微镜、扫描电镜-能谱、X射线衍射和电化学等技术对样品进行表征和测试。结果表明,随着锌镁质量比的降低,α(Al)的晶粒尺寸和析出物的粒径减小,析出物的体积分数增大。当锌镁质量比大于4.0时,Al-Zn-Mg阳极具有最低的腐蚀速率;当锌镁质量比小于0.62时,Al-Zn-Mg阳极具有最高的腐蚀速率且对碳钢(AISI 1018)具有最好的阴极保护效果。与其他阳极相比,锌镁质量比为0.62的Al-Zn-Mg阳极具有多孔腐蚀产物。

关 键 词：cathodic protection Al-Zn-Mg sacrificial anode current capacity passive film PRECIPITATE grain size 

分 类 号：TG174.41[金属学及工艺—金属表面处理]