Liu Xin, Lin Yufeng, Li Yu, Liu Nian
Department of Basic, Naval University of Engineering, Wuhan 430033, China.
Navy 91844 Troops, Guangzhou 510000, China.
Materials (Basel). 2024 Feb 8;17(4):811. doi: 10.3390/ma17040811.
Cathodic protection is widely used for metal corrosion protection. To improve their performance, it is necessary and urgent to study the influence of metal oxides on the microstructure and performance of aluminum alloy sacrificial anodes. Taking an Al-Ga-In sacrificial anode as the research object, the dissolution morphology and current efficiency characteristics were studied by means of electrochemical testing and microstructural observation, and the influence of varying Pb and Bi contents on the performance of an aluminum alloy sacrificial anode was investigated. The test results reveal that: (1) The Al-Ga-In sacrificial anode with 4% Pb and 1% Bi contents exhibits the best sacrificial anode performance. (2) The inclusion of an appropriate Bi element content shifts the open-circuit potential in a negative direction and promotes activation dissolution. Conversely, excessive Bi content leads to uneven dissolution, resulting in the shedding of anode grains and greatly reducing the current efficiency. (3) During the activation dissolution of the aluminum alloy, the second phase preferentially dissolves, and the activation point destroys the oxide film, resulting in the dissolution of the exposed aluminum matrix. Consequently, the concentration of dissolved metal ions is reduced and deposited back on the surface of the anode sample, promoting the continuous dissolution of the anode.
阴极保护广泛应用于金属腐蚀防护。为提高其性能，研究金属氧化物对铝合金牺牲阳极微观结构和性能的影响十分必要且迫切。以Al-Ga-In牺牲阳极作为研究对象，通过电化学测试和微观结构观察研究其溶解形态和电流效率特性，并研究了不同Pb和Bi含量对铝合金牺牲阳极性能的影响。试验结果表明：(1) Pb含量为4%、Bi含量为1%的Al-Ga-In牺牲阳极表现出最佳的牺牲阳极性能。(2) 适当的Bi元素含量会使开路电位向负方向移动并促进活化溶解。相反，过量的Bi含量会导致溶解不均匀，导致阳极晶粒脱落并大大降低电流效率。(3) 在铝合金的活化溶解过程中，第二相优先溶解，活化点破坏氧化膜，导致暴露的铝基体溶解。因此，溶解的金属离子浓度降低并重新沉积在阳极样品表面，促进阳极的持续溶解。
