稀土元素对铅合金耐腐蚀性能影响的研究

Study on the effects of rare earth elements on the corrosion resistance properties of lead alloys

以铅钙锡合金为母合金添加不同含量的稀土元素镧(La)和铈(Ce),制备圆柱形电极,并进行耐腐蚀性能实验测试。利用恒电位极化、计时电位法、失重法和电子显微镜(SEM)表征,对不同合金中的阳极腐蚀过程及腐蚀机理进行深入分析。稀土元素La和Ce加入到铅钙锡母合金中后,一方面可以细化合金晶粒和薄化晶界,从而降低晶界腐蚀的深度和宽度,另一方面可以增大表面氧化膜厚度,抑制电解液对基底的侵蚀,从而显著降低铅合金的腐蚀速率。

Cylindrical electrodes were prepared by adding lanthanum(La)and cerium(Ce)with different contents of rare earth elements in Pb-Ca-Sn alloy as the master alloy.The corrosion resistance was tested.The process and mechanism of anodic corrosion in different alloys were analyzed by potentiostatic polarization,chronopotentiometry,weightlessness and electron microscopy(SEM).The addition of rare earth elements La and Ce into the Pb-Ca-Sn parent alloy can,on the one hand,refine the alloy grain and thin the grain boundary,thus reducing the depth and width of grain boundary corrosion;on the other hand,it can increase the thickness of the oxide film on the surface and inhibit the corrosion of the substrate by electrolyte,thus significantly reducing the corrosion rate of the lead alloy.