Metal-based magnetic functional fluids with amorphous particles

Abstract

Two metal-based magnetic functional fluids, Ga–Sn and Ga–In magnetic liquids, were fabricated by doping with Fe_73.5Nb₃Cu₁Si_13.5B₉ metallic glass particles and nanoscale Fe₃O₄ particles, respectively. The saturation magnetization of the metallic glass particles, Fe_73.5Nb₃Cu₁Si_13.5B₉, is about 125 emu g⁻¹, nearly 50% larger than that of Fe₃O₄ crystalline particles which are usually used in water-based magnetic fluids. It is discovered that functional fluids, Ga_85.8In_14.2 and Ga_91.6Sn_8.4 alloy liquids, with Fe_73.5Nb₃Cu₁Si_13.5B₉ particles exhibit high saturation magnetization as well as low coercivity and remanence. Furthermore, the magnetic hysteresis curves confirm that the liquid metal-based magnetic functional fluids with Fe_73.5Nb₃Cu₁Si_13.5B₉ particles have higher magnetization than the metal-based Fe₃O₄ fluids. Owing to the high alloy boiling point more than 2000 K, the metal-based functional fluids should be useful materials for engineering applications when the surrounding temperature is relatively high. Interestingly, these functional fluids offer the properties of superior thermal or electrical conductivity over conventional water-based fluids.