Sm-Co permanent magnets: effects of fast neutron irradiation
Radiation-induced decay of remanence is investigated for Sm-Co5 and Sm2Co17 magnets irradiated with fast neutrons at temperatures below ambient with and without a bucking field. It is shown that most of the remanence is lost during the first minute of irradiation,i.e., at fluences of ≈2.5 × 1014 n/cm2. Also, different magnet materials, even with the same Co:Sm ratio, show markedly different decay rates. The effect of an applied bucking field and a low length-to-diameter ratio of the magnet is to increase the decay rate for a given neutron fluence. These remanence losses obtained with radiation are compared to results due to either an applied bucking field or annealing above 350 K.
