Preparation Of Al-Ce Alloy By Molten Salt Electrolysis

Al-RE alloys have broad application prospect and great development breadth and depth because of the characteristics of low specific gravity,high strength,high temperature resistance and corrosion resistance.Cerium is a "bad" by-product in rare earth mining,so the additional value of products is low,and the cerium glut has depressed prices for long.But now the application of Al-Ce alloy in aeroengine and internal-combustion engine makes the demand for cerium and Al-Ce alloy increasingly strong.Therefore,the research on preparation technology and properties of Al-Ce alloy is very important to improve the value of cerium products and promote the balanced and healthy development of rare earth industry.At present,mix-melting method is commonly used to prepare A1 alloys.Some studies show that performance of the alloys prepared by molten salt electrolysis is better than that of mix-melting method.In this paper,technique of Al-Ce alloy prepared by molten-salt electrolysis was investigated and the properties of the alloy prepared by two methods were studied.Technique and electrode process for preparing Al-Ce alloy by liquid A1 cathode process was studied.The influence of temperature,amount of NH4CI,time and vacuum degree on the dehydration effect of CeCl3 7H2O was investigated,and the technological parameters were determined.Electrochemical behaviors of Ce3+ on W electrode and liquid aluminum cathode in NaCl-KC1-CeCl3 were studied by cyclic voltammetry,square wave voltammetry and chronopotentiometry.The results show that the electrochemical reduction process of Ce3+/Ce on the W electrode is a quasi-reversible process of three electronic reactions in one step,and the electrochemical process is controlled by diffusion.The reduction of Ce3+ on the liquid aluminum cathode has obvious depolarization effect,and the depolarization value is about 1.OV compared to the W electrode.The influence of CeCl3 content,cathode current density and electrolysis temperature on the current efficiency was studied in NaCl-KCl-CeCl3,the parameters of electrolytic process were determined,that is,CeCl3 content is 30%,cathode current density is 1.0 A/cm2,electrolysis temperature is 750?,the current efficiency is 92.3%.The influence of temperature,time and stirring method on distribution uniformity of alloy phase of Al-Ce intermediate alloy prepared by mix-melting method were discussed,results show that the Al-Ce alloy is composed of Al and Al11Ce3.Al-0.3Ce alloy was prepared by mix-melting method and liquid Al cathode process,and its mechanical properties and corrosion resistance were also investigated.The results show that the tensile strength of the alloy prepared by liquid Al cathode process increased by 12.1%,the elongation increased by 56.3%,and the corrosion resistance was significantly improved.The chlorination of AICl3 on CeO2 was explored in the NaCl-KCl-AlCl3,and the Al-12.8Ce alloy is obtained by codeposition.It was found that the distribution uniformity of the alloy phase was more uniform than that of the mix-melting method and liquid Al cathode process.Therefore,there is good reason to believe that the codeposition method is expected to be more widely used than the mix-melting method and the liquid Al cathode process in the future.