稀土元素对桥梁缆索用热浸镀Zn-10Al镀层钢丝耐蚀性能的影响

Effect of Rare Earth Elements on Corrosion Resistance of Hot-dip Zn-10Al Coated Steel Wire for Bridge Cables

通过双镀法制备Zn-10Al-xRE(x=0.05,0.08,0.11,0.14,0.17)五种热浸镀锌铝镀层,并利用中性加速盐雾试验、电化学实验及扫描电子显微镜(SEM)分析其腐蚀形貌及耐蚀性能。结果表明,五种镀层在中性加速盐雾试验下,可保证基体在120d以内不被腐蚀,而纯锌镀层在30d时已经出现红锈,证明Zn-10Al-xRE的耐蚀性能可达到纯锌镀层4~5倍。Zn-10Al-xRE镀层钢丝的耐蚀性能随稀土含量的上升先升高再降低,添加0.08%RE的Zn-10Al镀层耐蚀性最好。用SEM对120d盐雾试验下的镀层钢丝进行观察,可以看出纯锌镀层的腐蚀产物较为疏松,Zn-10Al-xRE的腐蚀产物较为致密,Zn-10Al-xRE中腐蚀产物大约分为韧窝状、球状及针片状,耐蚀性能最好的Zn-10Al-0.08RE镀层中含有大量韧窝状腐蚀产物。

Five kinds of hot-dip galvanized aluminum coatings of Zn-10Al-xRE(x=0.05,0.08,0.11,0.14,0.17)were prepared by double plating method,and neutral accelerated salt spray test,electrochemical test and scanning electron microscope were used(SEM)analysis of its corrosion morphology and corrosion resistance.The results show that the five coatings can ensure that the substrate is not corroded within 120 d under the neutral accelerated salt spray test,while the pure zinc coating has red rust at 30 d,which proves that the corrosion resistance of Zn-10Al-xRE can reach pure the zinc coating is 4~5 times.The corrosion resistance of Zn-10Al-xRE coated steel wire first increased and then decreased with the increase of rare earth content,and the corrosion resistance of Zn-10Al coating with 0.08%RE was the best.Observing the coated steel wire under the 120 d salt spray test with SEM,it can be seen that the corrosion products of pure zinc coating are relatively loose,the corrosion products of Zn-10Al-xRE are relatively dense,and the corrosion products in Zn-10Al-xRE are roughly divided into dimples the Zn-10Al-0.08RE coating with the best corrosion resistance contains a large number of dimple-shaped corrosion products.