Experimental Proof of Microwave Sintering of Nd–Fe–B Powders Toward Fabrication of Permanent Magnets

The Nd–Fe–B magnets were prepared using conventional and microware sintering processes. A finely tuned microwave cavity operating in the 2.45 GHz, which works in single mode of electric field (e-field), was used to investigate the microwave sintering of Nd–Fe–B powders. The highest sintering temperature used was 1173 K, and the sintering lasted up to 610 s. The density of microwave sintered Nd–Fe–B magnets could reach values as high as 7.43 g/cc. We have managed to sinter Nd–Fe–B powders and produce magnets at a fraction of the time and energy used in conventional resistive/radiant heating, which is in excess of 1273 K for many hours, and in many cases after homogenization at high temperatures.