| Aluminum alloy is one of the most widely used metal materials in industry. With the development of society, it is very important to develop a new type of aluminum alloy with high performance. Research shows that rare earth yttrium as an additive into aluminum alloy can refine the microstructure, remove defectsand greatly improve material properties. The element yttrium is usually added to the aluminum alloy in the form of an yttrium aluminum alloy. At present, the process of preparing yttrium aluminum alloy mainly depends on the method of mixed melting. There are problems of high pollution and high energy consumption in the process of production. The large difference of the melting point will lead to uneven composition in the process of mixed melting. For the current existing problems, it is very important to explore a new preparation technology. As a new type of electrolytic technology, the FFC cambridge process has great advantage in the preparation of metal or alloy.In this paper,yttrium-aluminum intermediate alloy was prepared by the method of electro-deoxidation in molten salt CaCl2. The preparation process of cathode in electrolysis process and the chemical changes in the process of electrolysis were mainly studied.Various preparation conditions and electrolysis conditions were optimized, and the best parameters were obtained. Finally, the yttrium-aluminum intermediate alloy with low oxygen was prepared.In the first part of the experiment, the effect of sintering on composition, morphology and porosity of the mixed cathode was studied.The best sintering mechanism was obtained by electrolysis experiment of cathode pellets with different sintering conditions.The sintering temperature has great influence on the composition and morphology of the cathode.After sintering at low temperature, the composition of the cathode pelletswere still the mixture oxides, the microstructure of the cathode was regular and the particle distribution was uniform; With the increase of sintering temperature, a new material was produced in the cathode pellets, and the morphology was in the shape of the glass, the porosity was decreased significantly.The electrolytic product was a single YAl2 phase, and the microstructure was regular, and the oxygen content in the product was low after sintering at 900℃.The influence of sintering time on the composition and morphology of the cathode was relatively small.After sintering at different time, the composition of the cathode pelletswere still the mixture oxides, the morphology was more regular, no glass shape appeared, the porosity decreased with the sintering time prolonging.After sintered 4 h,the electrolytic product was a single YAl2 phase, the morphology of the electrolytic product showedthe clear sponge, the oxygen content was reduced to 1.85%.In the second part of the experiment, the mechanism of electrolytic process was studied based on the optimum sintering mechanism, and the effect of electrolytic temperature on the electrolytic process was studied.The electrolytic mechanism was speculated by analyzing the composition of the products under different electrolysis time.It was found that the electro-deoxidation process included many steps from raw materials to products, and YAl2 alloy was prepared after electrolysis.The microstructure of the product at different electrolysis temperature was uniform, the composition was single YAl2, and the oxygen content in the product was gradually decreased with the increase of the electrolysis temperature.In the third part of the experiment, the experiment of different ratio of yttrium aluminum oxide electrolysis were carried out.The results showed that the mixed oxides with the ratio of YAl2 was completely electrolytic under the same conditions of cathode preparation and electrolysis.The other ratio of mixed oxide electrolysis did not get the corresponding products. In subsequent research, if want to get other ratio of yttrium aluminum alloy,it need more strict control of preparation conditions and electrolytic conditions, there is still a lot of work to do.In this paper, yttrium aluminum alloy was successfully prepared, which provides the theoretical basis and preparation conditions for the preparation of rare earth alloy by cathode electrolysis of mixed oxides, provides a new idea for the preparation of rare earth aluminum alloy. |
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