Superior deoxidation performance of mixed molten CaH2–LiCl to prepare high-entropy CrMnFeCoNi alloy powders from metal oxides

CrMnFeCoNi high-entropy alloy powders were prepared by reducing a physical mixture of Cr 2 O 3 , MnO 2 , Fe 2 O 3 , Co 3 O 4 , and NiO at 850 °C using molten CaH 2 or mixed molten CaH 2 –LiCl as a reducing agent. However, the powders obtained using mixed molten CaH 2 –LiCl contained smaller amounts of impurities resulting from the corrosion of the SUS 316 containers, than those obtained using molten CaH 2 , indicating that the mixed molten salt has a milder corrosion capacity. In addition, oxygen removal from the raw metal oxides was faster in molten CaH 2 –LiCl than in molten CaH 2 , indicating that the mixed molten salt has a higher deoxidation capacity than the single salt. It was suggested that a calcium hydride halide (Ca 7 H 12 Cl 2 ) detected in the mixed molten salt could be concerned with the superior deoxidation performance. Finally, the lowest remaining oxygen content (0.21 wt%), corresponding to 99.3 % oxygen removal from the raw metal oxides, was achieved in the CrMnFeCoNi alloy powder prepared using CaH 2 –LiCl with twice the stoichiometric amount of CaH 2 with a reduction time of 20 h. • CrMnFeCoNi high-entropy alloy prepared from metal oxides using mixed molten CaH 2 –LiCl. • A physical mixture of Cr 2 O 3 , MnO 2 , Fe 2 O 3 , Co 3 O 4 , and NiO used as raw material. • Mixed molten salt showing a superior deoxidation capacity with 99.3 % oxygen removal.