Phase transformation mechanism and magnetic properties of Sm-Fe alloys produced by melt-spinning and high-energy ball milling

摘要

The phase transformation mechanism and magnetic properties of the Sm-Fe alloy powders produced by melt-spinning and high-energy ball milling are investigated. The amorphous phase is stable between 2 and 5 h, and the SmFe_9 phase is precipitated from the amorphous matrix after milled for 5 h. The time of 3-5 h is optimal to obtain the largest number of short-range/medium-range order in the amorphous alloy, which can contribute to the formation of uniform microstructure in the subsequent crystallization annealing process. The magnetic properties of the nitrided powders produced by crystallizing the amorphous precursors are improved compared to the properties of those produced by direct melt-spinning. The coercivity (H_(cj)) and the remanence (B_r) are increased by 1.28 kOe and 23.6 emu/g, respectively. This kind of micro-regulation plays a key role in improving the magnetic properties after nitrogenating and lays the foundation for the production of bulk materials in the future.