Preparation of FeCoNi medium entropy alloy from Fe3+-Co2+-Ni2+ solution system

In recent years, medium entropy alloys have become a research hotspot due to their excellent physical and chemical performances. By controlling reasonable elemental composition and processing parameters, the medium entropy alloys can exhibit similar properties to high entropy alloys and have lower preparation costs. In this paper, a FeCoNi medium entropy alloy precursor was prepared via sol-gel and co-precipitation methods, respectively, and FeCoNi medium entropy alloys were prepared by carbothermal and hydrogen reduction. The phases and magnetic properties of FeCoNi medium entropy alloy were investigated. Results showed that the decompose temperature of the precursor prepared by sol-gel and co-precipitation methods was 369 °C and 834 °C, respectively. FeCoNi medium entropy alloy was produced by carbothermal and hydrogen reduction at 1500 °C. Some carbon was detected in the FeCoNi medium entropy alloy prepared by carbothermal reduction. The FeCoNi medium entropy alloy prepared by hydrogen reduction had uniform composition, and showed a relative high purity. Moreover, hydrogen reduction product exhibited a higher saturation magnetization and lower coercivity.