抄録
The change of thermal dilatation during the aging process of Alnico 5 treated at various aging temperatures was observed and discussed. The result was compared with the previous result of the measurement on the temperature dependence of electrical resistance and it was found that the result supported the previous conclusion. The outstanding changes observed were that of contraction at 350 to 550°C, the great expansion at 550° to 650°C, and the change of expansion at 700 to 800°C; They vary with aging conditions. Thus, it was concluded that there are two different kinds of transformation mechanism during the aging process. One, which occurs below about 600°C may be something like order-disorder transition, and the other is a precipitation which occurs during the aging process above 650°C. It seems that the former mainly causes the best magnetic properties.
