Al-mg-x (hg, Sn, Ga) The Organization And Performance Of Anode Materials Research

The properties of electrochemical and corrosion resistance of Al anode materials depend on alloying elements and microstructure. Against some problems such as non-uniform dissolving and low current efficiency in Al anode materials, it is necessary to choose proper alloying elements and study their activity mechanisms on Al anode materials. Further studies on accurate Al alloy phase diagrams, the influence of second phases as well as microstructure evolution on electrochemical and corrosion properties of Al anode materials are meaningful for alloy design, microstructure controlling and heat treatment technology decision of Al anode materials with high activity in power seawater battery. In this work, Al-Mg-X(Hg,Sn,Ga) ternary alloys which were prepared by smelting and founding was developed by orthogonal design. The influences of alloy compositions and second phases and heat treatment technology on the properties of Al anode materials were investigated by electrochemical and microstructure measurements. This work is comprised of three parts as follows.1,The influences of Mg and X(Hg,Sn,Ga) content on Al-Mg-X(Hg,Sn,Ga) anode materials were studied through scanning electron microscope(SEM) and electrochemical measurements. The results demonstrate that the adjustment of Mg content have great effect in alloy dissolution and accelerate self-corrosion at 80℃4.5%NaOH solution,but the element Hg can control this acceleration at the same time improve activity of anode.The second phase composed by Mg and Sn can become the active points to bring pitting. The low content of Ga will result in negative work potential and low corrosion current density of Al anode.The Al-0.5%Mg-0.12%Ga anode has the best activity which adapt to the demand of high power battery.2,The influences of thermal treatment on Al-0.5%Mg-0.12%Ga anode materials were studied through SEM analysis and electrochemical measurements analysed the microstructure alteration after 450℃,500℃,550℃homogenization and 250℃,300℃,350℃annealing. The results demonstrate that the second phase can distribution uniformly after homogenization, especially homogenization of 500℃-4h had the best comprehensive performance.The defects from rolling can dissolve by annealing which can reduce the active points of corrosion. The recrystallization produced through annealing of 300℃-4h, and control the growth of grain, which make the anode have better properties3,The corrosion type of the Al-0.5%Mg-0.12%Ga anode materials and the activity mechanism were studied through SEM analysis,electrochemical measurements and solution and aging. The results demonstrate that the activity of the anodes is reduced by solution,but the corrosion resistance is increased. Acoording the aging at 200℃the second phase precipitate from the inside of grains and its number and volume increase with time,which make the stable potential become negative and evolution rate increase. The corrosion type of the Al-0.5%Mg-0.12%Ga anode materials is coexistence of galvanic corrosion,piting and intergranular corrosion.At the beginning of the dissolution the second phases formed by Mg and Ga which was dissolved in Al basal body formate activator between Al basal body and oxide film, they can inbibit the formation of compact oxide film, strengthen the activity of alloy;And then the element Ga follow the mechanism of dissolution-redeposition, promote dissolution fo Al anode sequentially.