A1基Pb-Ag合金复合阳极的制备及其性能试验研究

Preparation and Performance of Al-based Pb-Ag Alloy Composite Anode

研究了在铝棒表面通过挤压复合技术包覆铅银合金得到Al基铅合金复合阳极,并在硫酸锌溶液中以500 A/m2恒电流条件下极化48 h,采用X射线衍射、扫描电子显微镜、循环伏安法、阳极极化和交流阻抗法等分析阳极表面氧化膜层物相、形貌及电化学性能,采用显微图像分析仪和数显显微硬度计表征合金金相及硬度,并通过电子拉伸试验测定阳极的极限抗拉强度。结果表明:所制备的Al基复合阳极为Al基Pb-0.2%Ag和Al基Pb-0.75%Ag;合金中银含量增加,合金阳极的析出氧过电位降低,催化活性及耐腐蚀性能提高,合金组织的晶型结构改变较大,但机械性能变化不大;含银量高的阳极表面,氧化层排列不规则,晶粒大,粗糙度大;银含量增加,PbO_(2)(111)含量降低,β-PbO_(2)含量增大,但变化不明显;较高含量β-PbO_(2)可以提高阳极表面氧化层的导电性能。

The Al-based lead alloy composite anode was prepared by coating lead-silver alloy on the aluminum rod surface by extrusion composite technology.The anode was polarized for 48 h in a zinc sulfate solution at a constant current of 500 A/m2.The oxide film on anode surface were characterized by X-ray diffraction,scanning electron microscope,cyclic voltammetry,anodic polarization and AC impedance method.The metallographic and hardness of the lead alloy were also characterized by microscopic image analyzer and the digital microscope hardness tester.The ultimate tensile strength of the composite anode was determined by electronic tensile test.The results show that the prepared Al-based composite anodes are Al-based Pb-0.2%Ag and Al-based Pb-0.75%Ag,and the oxygen evolution overpotential of the anode decreases and the catalytic activity and corrosion resistance increases with the silver content in the alloy increasing.The change of silver content changes obviously the alloy crystal structure,but has little effect on the anode mechanical properties.On the anode surface with high silver content,the oxide film layer arranges irregularly with large crystal grains and large roughness.With silver content increasing,the PbO_(2)(111)content decreases slightly and theβ-PbO_(2) content increases slightly.A higher content ofβ-PbO_(2) can improve the conductivity of anode surface oxide layer.