Article ID Journal Published Year Pages File Type
1800897 Journal of Magnetism and Magnetic Materials 2010 4 Pages PDF
Abstract

Effects of post-sintering annealing on the microstructure and coercivity have been investigated for the Al85Cu15-added (Pr, Nd)14.8Fe78.7B6.5 sintered magnets. It is found that the optimum annealing temperature at which the coercivity iHc reaches a maximum decreases from 550 °C for the magnets added with 0.3% and 0.6% Al85Cu15 to 480 °C for the magnets added with 0.9% and 1.2% Al85Cu15. The decrease in optimum annealing temperature is related to the precipitation of Al–Cu or (Pr, Nd)−Cu liquid phase among (Pr, Nd)-rich phases during annealing. Existence of Al–Cu or (Pr, Nd)−Cu liquid phase is beneficial to dissolve the irregularities of (Pr, Nd)2Fe14B grain interface and increase the quantities of (Pr, Nd)-rich phases at the grain boundary, thus optimizing the grain boundary microstructure. The modifications of the microstructure are helpful to decouple the exchange interaction between (Pr, Nd)2Fe14B hard magnetic grains, thereby increasing the coercivity.

Related Topics
Physical Sciences and Engineering Physics and Astronomy Condensed Matter Physics
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