Preparation Of Mg-Li Mg-Li-Zr Zn-Zr Alloys By Electrolysis In Molten Salt

The Mg-Li,Mg-Li-Zr,Zn-Zr alloys were prepared by electrolysis in molten in this paper.A new technology for preparation of low cost Mg-Li alloys was studied. The alloys were prepared by electrolysis in molten LiCl-KCl(weight ratio is 1:1) electrolyte with Mg rod severing as the consumed cathode. Main factors that affect current efficiency were investigated and optimal electrolysis parameters were obtained. Mg-Li alloys with 30～34 wt% Li were prepared in electrolyte containing 50±2 wt % LiCl at 450～480℃. The mean current efficiency of Li reached to 91.4%. Mg-Li alloys with low lithium content(about 25%) were prepared by the method of a higher heat preservation treatment after electrolysis at low temperature. The results showed that the electrolysis could be carried out at low temperature and this reduced preparation cost in order to energy saving. The new technology for the preparation of Mg-Li alloy by electrolysis in molten salt was proved to be feasible.The preparation of Mg-Li-Zr alloy was explored. The alloys were prepared by electrolysis in molten KCl-K₂ZrF₆(weight ratio is 3:1) electrolyte with Mg-Li alloys severing as liquid cathode at 750℃. The melting point of K₂ZrF₆ was about 840℃, KCl was an assistant electrode that was used to reduce the temperature of system. in the range of electrolysis temperature, the melted metal Mg-Li(8%wt) did not volatilizate and the cathode did not damnify. Electrochemical measurement showed that ZrF6₂^2- had different decomposition voltage on the different electrode. SEM and EDS results indicated that the Zr atom proliferated rulelessly in the Mg-Li alloy.The preparation of Zn-Zr alloy was explored. The alloys were prepared by electrolysis in molten KCl-NaCl(LiCl)-K₂ZrF₆(weight ratio is 21:21:8) electrolyte with Zn alloys severing as liquid cathode. In the range of electrolysis temperature investigated in this study, the melted metal Zn did not volatilizate and the cathode did not damnify. NaCl puted into electrolyte system could reduce the melting point of the electrolyte syetem, increase the flow of electrolyte system, increase the difference of surface tension of melted salt and alloys and be propitious to separate alloys from impurities. Raplacing NaCl could reduce the temperature of the electrolyte syetem. By using X radial diffraction,SEM and EDS, the impact of current density, electrolysis time and electrolysis temperature on the composition was investigated. In the conditions of the same electrolysis time 1h,electrolysis temperature 760～765℃, the impact of different current density on the alloys was investigated. In the conditions of the same current density 0.45 A/cm²,electrolysis temperature 760～765℃, the impact of different electrolysis time on the alloys was investigated. In the conditions of the same electrolysis time 1h,current density 0.45A/cm², the impact of different electrolysis temperature on the alloys was investigated, results showed that Zr atom proliferated rulelessly frome surface to inside of metal Zn. The electrolysis can be carried out at the lower current density 0.2A/cm²,the shorter electrolysis time 20min and the lower electrolysis temperature 500℃. the preparation of Zn-Zr alloy by electrolysis in molten salt was proved to be feasible.