Liquid metal Ga-Sn alloy based ferrofluids with amorphous nano-sized Fe-Co-B magnetic particles

Amorphous Fe-Co-B nano-sized magnetic particles were prepared and firstly introduced into Ga 91.6 Sn 8.4 alloy to fabricate liquid metal-based ferrofluids. The Fe-Co-B particles are amorphous and spherical with an average particle size of 10.6 nm. The saturation magnetization of amorphous Fe-Co-B nanoparticles after annealing treatment at 550 °C is 81 emu/g, which is higher than that of Fe-Co-B nanoparticles without and after annealing treatment at 450 °C. The annealed Ga 91.6 Sn 8.4 alloy-based ferrofluids with amorphous Fe-Co-B nanoparticles exhibit high stability, which is superparamagnetic with a saturation magnetization of 2.57 emu/g. Besides, the Ga 91.6 Sn 8.4 alloy-based ferrofluids show temperature-sensitive magnetic property. The magnetoviscous property demonstrates that the annealed Ga 91.6 Sn 8.4 alloy-based ferrofluids show relatively strong magnetic responsiveness. The hysteresis curves of viscosity–magnetic field show the annealed Ga 91.6 Sn 8.4 alloy-based ferrofluids have superior reversibility and exhibit a desirable high-temperature performance.