退火溫度對燒結Nd_(15)Fe_(77)B_8磁石微結構及磁性的影響

Effect of Annealing Temperature on the Microstructure and Magnetic Properties of a Sintered Nd_(15)Fe_(77)B_8 Magnet

洪銘盤(M. P. Hung) ； 黃明山(M. S. Huang) ； 蔡篤幸(D. S. Tsai) ； 張炎輝(Y. H. Chang) ； 金重勳(T. S. Chin)

《鑛冶：中國鑛冶工程學會會刊》 32卷1期 (1988/03) Pp. 93-102

https://doi.org/10.30069/MM.198803_32(1).0009

摘要

Nd_(15)Fe_(77)B_8合金塊經過2.5小時的振動研磨，垂直磁場（12KOe）下壓型，在1090°C燒結一小時後水中淬火至室溫而得異方性磁石。磁石再經過400°至700℃，一小時的退火後，Br隨退火溫度上升而一直減少，iHc則隨退火溫度由400°升至550℃而增加，但自550℃起開始下降。由金相及X光繞射觀察判斷，上述結果與退火期間中，Nd_2Fe_(14)B共晶相異方性及形態之變化有關。

並列摘要

A sintered Nd_(15)Fe_(77)B_8 magnet was prepared by the following powder metallurgy techniques. The alloy powders were vibration-milled for 2.5 hours, compressed in a vertical magnetic field (12 kOe), sintered at 1090°C for one hour and finally quenched in water to room temperature. The sintered magnets were then subjcted to annealing in the range of 400° to 700°C for one hour and quenched in water to room temperature. As a result, remanence decreased monotonously with increasing annealing temperature, while intrinsic coercivity increased with increasing annealing temperature from 400° to 550°C and fell off at 550°C. From the metallographic and X-ray diffraction observations, it is deduced that the variation in the anisotropy and morphology of the eutectic Nd_2F_(14)B phase during annealing is liable for the above-mentioned results.