Alloying Elements And Solid Solution Treatment On The Microstructure And Mechanical Properties Of Magnesium Ap65 Anode

The electrochemical properties and corrosion resistance of AP65magnesium anode depend on the alloy composition and microstructure. To overcome the shortages of severe corrosion, positive potential and long activation time in AP65anode, we choose proper alloying elements and explore their influence on the microstructure and electrochemical properties of AP65magnesium anode. The microstructure and electrochemical properties of AP65-1.5In anode have been examined in3.5%NaCl solution after solution treatment, which will provide theoretical basis for the preparation of high performance AP65anode materials.The influences of Sn, Mn, Zn and In elements and their contents on the microstructure and electrochemical properties of AP65anodes were studied. The four kinds of AP65anodes have similar microstructure, their structures are a-Mg, Mg17Al12and Mg+Mg2Sn, a-Mg and Mg+Mg17Al12, α-Mg and Mg17Al12, a-Mg and Mg+Mg17Al12. The addition of Sn cannot improve the electrochemical activity and corrosion resistance of AP65anode significantly, but after0.7%Mn and1.0Zn%addition, the corrosion resistance and the electrochemical activity of AP65anode improved slightly. The effects of In on AP65anodes are to enhance the corrosion resistance and improve the electrochemical activity obviously. AP65-1.5In have good comprehensive performance in comparison.The influences of solution treatment on microstructure and electrochemical properties of AP65-1.5In anode were studied. The experimental results show that, the β-Mg17Al12phase solubilizes into the a-Mg matrix, the cathode-to-anode area ratio of the anodes decreases, and the self-corrosion rates increase after solution treatment. The corrosion current density of AP65-1.5In anode increases from0.023to0.283mA/cm2and the corrosion potential of positive shift from-1.370V to-1.268V after solution treatment. Since excellent performance cannot be obtained by sole solution treatment, rolling and annealing are needed in the following research.The corrosion behaviors of AP65anode in3.5%NaCl solution were explored. Pit corrosion and crevice corrosion promote each other during the corrosion process of AP65anode. On the one hand, the crevice corrosion of pitting hole spreading in a radial way, result in a-Mg matrix particles fall off and the scope of pitting hole expanded. Pitting corrosion at the bottom of the hole is inside development, and constantly expand the depth of the hole. On the other hand, pitting corrosion create conditions for crevice corrosion. And defects inevitable emerge in the surface of AP65anode, where provide places for crevice corrosion. Moreover, pitting corrosion make the medium produces concentration sent and provides convenience for the generation of crevice corrosion.