摘要
Zn是钢防腐常用的金属。进一步添加其他元素,如Ni,可以降低其腐蚀速率,保持其牺牲性保护作用。采用动电位、恒电位和恒电流技术研究Zn、Ni和不同Ni含量（0.5%~10%）的Zn-Ni合金在3.5%Na Cl溶液中的阳极溶解行为。利用EDX和SEM对Zn,Ni和Zn-Ni合金腐蚀层的成分和显微组织进行表征。恒电位曲线表明,所有研究电极的阳极行为都呈现活化/钝化转变,而且除99.5Zn-0.5Ni合金外,随着Ni含量的增加,合金的钝化趋势减弱。而动电位曲线表明,只有Zn表现出活化/钝化转变。表面分析表明,腐蚀产物主要为氧化物、氯化物和氢氧氯化物。与Zn相比,90Zn-10Ni合金中可观察到细微的裂纹。
Zinc is common metal used for steel protection from corrosion.The addition of further element,such as Ni,can modify the corrosion rate and maintain sacrificial protection.The anodic dissolution behavior of Zn,Ni and Zn-Ni alloys with different Ni contents（from 0.5% to 10%,mass fraction） in 3.5% Na Cl solution was investigated using potentiodynamic,potentiostatic and galvanostatic techniques.The composition and microstructure of the corrosion layer on Zn,Ni and Zn-Ni alloys were characterized by energy-dispersive X-ray spectroscopy analysis（EDX） and scanning electron microscopy（SEM）.The galvanostatic curves show that the anodic behavior of all investigated electrodes exhibits active/passive transition and the tendency of the alloys to passivity decreases with the increase in Ni content,except for 99.5Zn-0.5Ni alloy.While the potentiodynamic curves exhibit active passive transition only for pure Zn.Surface analysis reveals the presence of oxides,chlorides and metal hydroxide chloride in corrosion products,and very small cracks are observed for 90Zn-10 Ni alloy compared with that of Zn.
