稀土对锌基牺牲阳极材料耐蚀性的影响

Effect of Rare-earth on Corrosion Resistance of Zinc-based Sacrificial Anode Material

以Zn-30%Al合金为研究对象,通过改变混合稀土(La,Ce)的含量,制备新型合金涂层材料。通过电化学性能分析,考察合金元素的种类和含量对合金表面溶解状况的影响;借助金相显微镜,对合金组织进行探讨和研究。发现:混合稀土(La,Ce)加入后,在3.5%NaCl溶液中,合金的开路电位和腐蚀电位均有所负移,腐蚀电流减小;在1mol/L HCl溶液中,合金的腐蚀电流有所减小,说明稀土的加入降低了合金在酸性溶液中的自腐蚀率。其中添加1.0%Re的锌铝合金在1mol/L HCl溶液中保护效果最好,表面形成了一层明显的白色氧化膜。

Zn-30%Al alloy was taken as study object,Zn-Al alloys of different content of RE（La,Ce） are cast.Their electrochemical performances are tested with constant current method.Microstructures are also observed and analyzed by metallographic microscope,in order to study the alloy surface dissolution conditions affected by the type and content of alloying elements.Conclusions as follows： the corrosion potential and open circuit potential becomes more negative and less the rate of self-corrosion in Zn-Al-Re in 3.5%NaCl solution after mixed with rare earth（La,Ce） addition.Also,the same result was revealed in 1 mol/L HCl solution,Zn-Al alloy with 1.0% Re content shows the best corrosion resistance,which surface produce a dense passive film.