活化元素对锌合金牺牲阳极电化学性能的影响

Effect of Active Elements on Electrochemical Performance of Zinc Alloy Sacrificial Anodes

目的 满足深潜装备用高强钢材料阴极保护需求,探明活化元素对锌合金牺牲阳极电化学性能的影响规律。方法 采用合金化设计方法,控制活化元素,制备新型锌合金牺牲阳极。通过常规电化学性能试验、电化学测试、扫描开尔文探针测试数据及微观形貌表征结果,综合分析活化元素对锌合金牺牲阳极组织和综合性能的影响,探明低驱动电位锌合金牺牲阳极性能的变化规律。结果 添加Ga、Mn、Sn和Cd活化元素的牺牲阳极,表面溶解形貌相对均匀,阳极电位发生不同程度的正移,用于阴极保护时,驱动电位得到降低,其工作电位基本处于–1.02~–0.8 V(vs. Ag/AgCl),牺牲试样呈现表面溶解活性降低、溶解速率变慢的趋势。结论 通过添加各类活化元素,均使锌合金牺牲阳极性能得到不同程度的优化改善。Cd元素可增大阳极试样表面的杂乱度,随Sn、Mn含量的增加,牺牲阳极试样的晶粒尺寸得到一定细化。其中,Zn-0.5Mn系列牺牲阳极较满足高强钢阴极保护的需求,工作电位为–0.95~–0.84V(vs.Ag/AgCl),表面活性位点分布均匀,可进一步开发适用于高强钢结构材料阴极保护的新型牺牲阳极。

The work aims to explore the influence of activating elements on the electrochemical performance of zinc alloy sacrificial anodes to meet the cathodic protection requirements of high-strength steel materials for deep diving equipment.A new type of zinc alloy sacrificial anode was prepared according to the alloying design method to control the activation elements.Through conventional electrochemical performance tests,electrochemical tests,scanning Kelvin probe test data,and micro-structure characterization results,the influence of activation elements on the microstructure and comprehensive properties of zinc alloy sacrificial anodes was comprehensively analyzed,and the changes in the performance of low driving potential zinc alloy sacrificial anodes were explored.The surface dissolution morphology of the sacrificial anode added with Ga,Mn,Sn,and Cd activation elements was relatively uniform,and the anode potential underwent different degrees of positive shift.When used for cathodic protection,the driving potential was reduced,and its working potential was basically within the range of-1.02~-0.8 V(vs.Ag/AgCl).The sacrificial sample showed a trend of decreased surface dissolution activity and slower dissolution rate.By adding various activating elements,the sacrificial anode performance of zinc alloy is optimized and improved to varying de-grees.Cd element can increase the surface disorder of the anode sample,and the grain size of the sacrificial anode sample is re-fined to a certain extent with the increase of Sn and Mn content.Among them,the Zn-0.5Mn series sacrificial anode better meets the cathodic protection requirements of high-strength steel,with a working potential of-0.95~-0.84 V(vs.Ag/AgCl)and a uni-form distribution of surface active sites.Further development of new sacrificial anodes suitable for cathodic protection of high-strength steel structural materials is possible.