Effect of sintering temperature on microstructure and properties of Nd_24.38Ce_0.52Gd_6.65Fe_bal.TM_1.76B_0.95 magnet

Nd_24.38Ce_0.52Gd_6.65FebalanceTM_2.18 B_0.95(mass fraction, %) permanent magnets were prepared using dual-alloy technology.The effect of sintering temperature on the microstructure and properties of the magnets was probed by scanning electron microscopy, energy dispersive spectrometer, AMT-4 magnetic tester and electronic universal mechanical testing machine.The sintering temperature applied in the article ranged from 1 060℃ to 1 100℃.The results show that when the sintering temperature is 1 080℃, the best microstructure of the magnets is obtained with uniform and tight grains and even-distributed Re-rich phase; with the sintering temperature rising from 1 060℃ to 1 100℃, the content of Re in Re-rich phase rapidly increases from 84.98% up to 98.04% and the diffusion of Ce from the main phase to the Re-rich phase is greatly improved during the sintering process; magnetic remanence (B_r), coercivity (H_cj), and maximum energy product(BH) _max of the magnets raise first and then decrease as the increase of sintering temperature; when sintered at 1 080℃, the magnets exhibits the best properties, with B_r of 1.22 T, H_cj of 964 kA/m and (BH) _max of 293 kJ/m³, along with the maximum bending strength of 257 MPa.