硼对电解锌用铝阴极板组织与耐腐蚀性能的影响

Effect of Boron on the Structure and Corrosion Resistance of Electrolytic Zinc with Aluminum Cathode Plates

通过在780℃熔融工业纯铝(1070)中添加硼酸盐(Na_2B_4O_7),制备了电解锌用铝合金阴极板,研究了硼酸盐添加量与反应时间对阴极板显微组织与耐蚀性能的影响.研究结果表明,随着Na_2B_4O_7添加量的提高以及保温时间的延长,Al阴极板中的Fe相含量逐渐减少,且析出形貌由针状逐渐变为细小的颗粒状.因此,在铝熔液中加入Na_2B_4O_7可有效降低Al中的Fe含量,并改变Fe相的形貌.对不同Na_2B_4O_7添加量和保温时间所得到的Al阴极板在模拟电解液浸泡腐蚀实验以及电化学测试的结果表明:随着硼酸盐添加量的增加,合金阴极板的耐蚀性能逐渐增加,当硼酸盐的添加量为0.7%(质量分数),保温时间为60min时,所得到的Al阴极板Fe相含量最少,并表现出最佳的耐蚀性.

In the present study, the borate agents （Na2B4O7）were added to the Al melt at 780 ℃, and the cathode plates for the electrolytic zinc were prepared by casting method.The effects of the amount of the borate agents and the reaction time on the microstructure and corrosion behavior of the Al cathode plates were investigated. The results indicate that,with the additions of borate agents increasing and the reaction time prolonging,the volume fraction of the Fe-rich phases decrease,and the shape of the Fe-rich phases changes from the needle-like shape to the fine granular shape.Thus,the addition of the borate agents can reduce the Fe contains and change the shape of the Fe-rich phases.The corrosion behaviors of the Al cathode plates obtained with the different borate agents additions and reaction durations in the simulated electrolyte were evaluated by immersion corrosion tests and electrochemical property tests.The results indicate that,with the additions of borate agents increasing and the reaction time prolonging, the corrosion resistance of the Al cathode plate increases. The Al cathode plate obtained with 0.7% additions of Na2B4O7 and 60 min reaction duration exhibits the highest corrosion resistance due to its low contain of the rich-Fe phase.