Composition Design of High Bs Fe-Based Amorphous Powders with Good Sphericity

Abstract

Abstract: Fe83SixByC(17-x-y) has good amorphous forming ability (AFA), and high saturation magnetic induction (Bs), and spherical amorphous powder can be prepared using a gas-water two-phase coupling atomization (GWC) device. Herein, the effects of metalloid elements (B, C, Si, and P) on the thermal parameters and magnetic properties of the Fe83SixByC(17-x-y) powder are discussed. The research conclusion shows that the Fe83Si2.5B11.5C3 amorphous powder exhibits the best comprehensive performance. Through the Lorentz microscope pattern of Fe83Si2.5B11.5C3 amorphous powder, magnetic domains walls are observed to gather and interlace in the outer region of the particle. The Fe83Si2.5B11.5C3 amorphous powder exhibits a high initial crystallization temperature (Tx1), followed by a ΔTx of 27 ℃, and then crystallization completion at 561.1 ℃. Some clusters or primary crystals are produced in the amorphous matrix after annealing at 520 ℃ (below Tx1 534 ℃) for 1 h. A further increase in the annealing temperature to 570 ℃ (beyond Te1 561.1 ℃) causes the precipitation of a large amount of crystalline phase α- Fe (Si) and hard magnetic phase Fe2B, thereby resulting in the rapid deterioration of the magnetic properties of the amorphous powder.

Keywords: amorphous forming ability, high Bs, gas-water two-phase coupling atomization, magnetic domains walls, Annealing