High Magnetization Fe-Co And Fe-Ni Submicron And Nanosize Particles By Thermal Decomposition And Hydrogen Reduction

This paper reports morphology, structure, and magnetic properties of air-stable soft magnetic FexCo100-x (x = 65, 50, and 34) and Fe50Ni50 (at. %) submicron and nanosize particles fabricated by template-free thermal decomposition of nitrates of Fe, Co, and Ni and subsequent hydrogen reduction. The particle compositions were tuned by modification of the precursor solution concentrations. The as-synthesized Fe-Co and Fe50Ni50 particles have body centered cubic and face centered cubic poly-nanocrystalline structures, respectively. The Fe-Co and Fe50Ni50 particles have particle sizes in the range of 28-200 nm and 70-480 nm, and average grain sizes of 16-29 nm and 20-24 nm, respectively. The particle and grain sizes were controlled by tuning particle composition, and the temperature and time of hydrogen reduction. Saturation magnetization M-s as high as 207-224 emu/g and intrinsic coercivity H-ci of 59-228 Oe were obtained in the Fe-Co particles reduced at 550 degrees C for 90 min. Of special note, the M-s of 224 emu/g (similar to 2.3 T) obtained in the Fe65Co35 particles is among the highest values for Fe-Co particles reported so far. M-s of 135-137 emu/g and H-ci of 59-111 Oe were obtained in the Fe50Ni50 particles reduced at 500 or 550 degrees C for 20 min. (C) 2014 AIP Publishing LLC.