Gamma-ray irradiation on microsized Nd-Fe-B and Sr-ferrite magnets at low temperature.

The gamma-ray irradiation on microsized Nd-Fe-B and Sr-Fe permanent magnet at low temperature and room temperature was investigated. The change of shape and magnetic properties of two kinds of magnet powder before and after irradiation at low temperature was measured. The crystal structure of each permanent magnet powders was analyzed using X-ray powder diffraction (XRD) and the size and shape were characterized by scanning electron microscope (SEM).

The influence of low temperature on gamma-ray irradiated permanent magnets.

The temperature effect on the magnetic property of gamma-ray irradiated Nd-Fe-B and Sr-Ferrite magnets has been investigated. When the permanent magnets are exposed to gamma-ray, it's magnetic and other related properties are declined with degree of dose. The decreased magnetic property by gamma-ray irradiation at low temperature is similar with the result of magnet at high temperature.

Characterization on the microstructure of gamma-ray irradiated Nd2Fe14B magnet.

The effect of 60Co gamma-ray irradiation on the microstructure of Nd2Fe14B magnets was investigated with electron spin resonance (ESR) and thermal mechanical analyzer (TMA). When the 60Co gamma-ray with dose from 0 Mrad to 100 Mrad was exposed to Nd2Fel,4B magnet having different sizes at room temperature, the increased demagnetization properties of the Nd2Fe14B magnets were studied by Hall probe. For all samples, changed Curie temperature and micro-crystal structure of Nd2Fe14B magnet by gamma-ray irradiation has been also studied.