Factor Analysis on Coercivity of Hot-deformed Nd-Fe-B Magnets

摘要

Coercivity measurements, microstructure observations, and magnetic domain characterization of hot-deformed Nd-Fe-B magnets made with various conditions were conducted. Initial magnetization curves of hot-deformed magnets exhibit a two-step process with an inflection point. From the magnetic domain observation which shows that these samples consist of single-domain and multi-domain grains, it is thought that the two-step process of initial magnetization curve corresponds to the magnetization process of each grain. Coercivities of the samples increase with increasing of three factors (the ratio of single-domain content (SDGR), amount of total rare earth element, and Dy content). The multiple regression for coercivity was also carried out to study the influence of these factors. The effect of TRE on coercivity at 180°C decreses to about 1/2 of the RT values, while the coefficient of SDGR is almost constant. The increase of SDGR brings high coercivity and high heat resistance of hot-deformed magnets.