Synergistic Interaction Between NdCl3 and NdF3 in Magnesiothermic Reduction Process

To increase the reaction driving force and prepare Mg–Nd master alloys, the synergistic interaction between NdCl3 and NdF3 was used in the magnesiothermic reduction process in NdCl3–NdF3-containing molten salt. Thermomechanical analysis was used to investigate the possibility of the synergistic interaction in molten salt. Then the verification of synergistic interaction was conducted by analyzing the composition of the molten salt and the alloys obtained in the magnesiothermic reduction process. After that, the factors affecting synergistic interaction were investigated. At last, the mechanism of the synergistic interaction between NdCl3 and NdF3 in molten salt was proposed and discussed. The coupling reaction formed in the magnesiothermic reduction process and the existence of three reaction mechanisms increased the reaction driving force. Mg–RE master alloys with the content of Nd being 25 to 30 wt pct were prepared under the optimum conditions and the conversion rate of NdF3 was greater than 70.94 pct. The content of Nd and the content of various impurities in the alloys obtained both met the requirements of the commercial Mg–Nd master alloys.