Mg-Al alloys are widely used in various fields such as architecture and aviation due to their low density, high specific strength, good corrosion resistance and ease of processing. The components applied to special vehicles need to have high temperature creep resistance. The addition of a small amount of rare earth elements in the Mg-Al alloy can meet this requirement.
The research group led by Jang Pok Nam, an institute head at the Faculty of Metal Engineering, has already worked on the preparation of Mg-Al-La master alloy by chloride-fluoride molten salt electrolysis in MgCl2-KCl-AlF3-La2O3 system. In this method, AlF3 exists in a solid state in molten salts and it is consumed through chemical reactions going with electrolysis. However, the separation of this solid fluoride and the resulting master alloy is not easy and evaporation loss of chlorides is big due to relatively high electrolytic temperature.
Therefore, the research group has proposed a method of preparing Mg-Al-La master alloy by chloride electrolysis to reduce electrolytic temperature and facilitate the separation of electrolytes and alloys.
No studies have been reported on the preparation of Mg-Al-La master alloys by molten salt electrolysis in MgCl2-KCl-AlCl3 molten salts.
After preparing the Mg-Al-La master alloy by molten salt electrolysis in MgCl2-KCl-AlCl3 ternary molten salt, they have investigated the factors affecting the element contents and current efficiencies in the production of Mg-Al-La master alloy, such as electrolysis temperature, cathode current density and electrolysis time.
He has found that increasing electrolytic temperature favors the increase in the contents of Al and La in the alloy, and the optimum electrolytic temperature is 600-650℃, and that as cathodic current density and electrolytic time increase, the content of Mg in the alloy also increases steadily but the content of La decreases.
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