Fe_xCo_1-x alloy nanoparticles: Synthesis, structure, magnetic characterization and magnetorheological application

Highlights

• Synthesis of FexCo1-x good quality nanoparticles by the chemical reduction technique.

• FexCo1-x nanoparticles with bcc cubic structure and no impurities.

• FexCo1-x nanoparticles with good soft magnetic behaviour.

• FexCo1-x nanoparticles with saturation magnetization up to 235 emu/g.

• Good magnetorheological behaviour by using Fe47Co53 nanoparticles as fluid fillers.

Abstract

We present results concerning the synthesis of Fe_xCo_1-x (0 < x < 1) alloy nanoparticles (NPs) with different compositions by the chemical reduction technique and subsequent structural (XRD patterns), morphological (TEM images) and magnetic (VSM magnetometry) characterization. We have got excellent quality NPs in the cubic bcc structure showing a room temperature magnetization as high as 235 emu/g for the Fe₆₆Co₃₄ composition alloy. Powder of composition Fe₄₇Co₅₃ was used to fabricate a magnetorheological fluid (MRF) by using mineral oil as carrier liquid and Aerosil 300 as additive to control the viscosity of the fluid. This MRF showed a strong magnetorheological response with a superior performance under applied magnetic field up to 616.7 kA/m and good reversibility after demagnetization process. At that highest applied magnetic field, we determined a yield stress value of 2729 Pa, that competes well with the best ones reported in the most recent literature.