氟化物熔盐电解制备Al-Sc中间合金阴极过程的研究

The Al-Sc master alloy is the key raw material to produce the Aluminum alloy containing the metal Sc with the excellent performance such as lightweight, high strength, corrosion resistance, etc. The method of the molten salt electrolysis has attracted much attention due to the low-cost and the low-energy consumption. But during the electrolysis, there exits some shortcomings. For example, the current efficiency is low, the distribution of metal Sc is not uniform, and the size of the grain of intermetallic compound Al3Sc is too large. To solve these problems, this project intends to carry out the research on the cathode process of electrochemical preparation of Al-Sc master alloy in the fluoride molten salt..The following research is conducted which includes that the mechanisms of the reduction of Sc2O3 at the cathode, the kinetic characteristics of the reduction of Sc2O3 and the alloying process of the metal Sc, and the formation and its growth of intermetallic compound Al,Sc. From these, the precipitation mechanism of the metal Sc under the electrolysis conditions is discovered. The generation and evolution of intermetallic compound Al,Sc is also illuminated. And then, a control mechanism would be founded, which would realize that the high precipitation efficient and uniform distribution of the metal Sc. A synergy between the reduction of Sc2O3 and the alloying process of the metal Sc would be achieved during electrolysis.Thus, a theoretical basis of the technology for preparing the Al-Sc master alloy, which is based on the molten salt electrolysis, would be provided. It is advantageous to promote the extensive application of the Aluminum alloy containing the metal Sc. Simultaneously, a reference would also be provided for the development of the technologies for preparing binary alloy, multi-component alloy, or other refractory metal with the method of the molten salt electrolysis.

Al-Sc中间合金是生产具有轻质、高强、耐蚀等优异性能含Sc铝合金的关键原材料。熔盐电解法因能实现该材料的低成本、低能耗制备而备受关注。申请者针对该法制备Al-Sc中间合金过程中电流效率低、金属Sc分布不均、金属间化合物Al3Sc颗粒大等问题，提出开展氟化物熔盐电解制备Al-Sc中间合金的阴极过程研究。.通过研究氟化物熔盐电解过程Sc2O3的阴极还原机理，Sc2O3还原与金属Sc合金化过程的动力学，以及Al,Sc金属间化合物的形成与生长，揭示电解条件下金属Sc析出机制，明晰Al,Sc金属间化合物生成及演变规律，建立起金属Sc高效析出与均匀化分布的调控机制，掌握电解状态下Sc2O3还原与金属Sc合金化过程相互协同的方法，为创建低成本、低能耗制备Al-Sc中间合金的熔盐电解技术奠定理论基础，推动含Sc铝合金的广泛应用。同时，该项目研究也可为其他二元或多元合金以及难熔金属的熔盐电解法制备提供借鉴

Al-Sc中间合金是生产具有轻质、高强、耐蚀等优异性能含Sc铝合金的关键原材料。熔盐电解法因能实现该材料的低成本、低能耗制备而备受关注。项目针对该法制备Al-Sc中间合金过程中电流效率低、金属Sc分布不均、金属间化合物Al3Sc颗粒大等问题，开展了氟化物熔盐电解过程Sc2O3的阴极还原机理，工艺参数与熔体组成对金属Sc的析出过程的影响规律，以及金属Sc析出后的行为等研究。通过研究，弄清了Na3AlF6-K3AlF6-AlF3熔体内Sc2O3存在金属热还原与电化学还原，掌握了金属Sc与金属Al在Na3AlF6-K3AlF6-AlF3熔盐电解时的阴极析出调控原理，揭示了电解工艺参数与熔体组成对金属Sc阴极电解析出的影响规律，获得了可制备Sc含量达2.33 wt.%的 Al-Sc合金电解工艺参数，为创建低成本、低能耗制备Al-Sc中间合金的熔盐电解技术奠定理论基础，推动含Sc铝合金的广泛应用。同时，该项目研究也可为其他二元或多元合金以及难熔金属的熔盐电解法制备提供借鉴。