Temperature effect on magnetic characteristics of Fe-Cr-Co-Si alloy specimens processed by thermomagnetic treatments

Fe-Cr-Co magnets getting research focus due to the rapid increase of magnet demand, especially for super-speed motors owing to their remanence values equivalent to that of NdFeB super magnets. In this work, the magnetic characteristics in Fe-Cr-Co-Si alloy samples were induced by processing through isothermal thermomagnetic and step aging treatments, and then, the samples were investigated for thermal effect on magnetic characteristics. The effects of an increase in temperature on the remanence, coercivity and energy product were measured using a BH-Curve tracer. The specimens were prepared from the thermomagnetically processed and aged alloy bricks. Demagnetisation curves were measured at temperatures ranging from 20 °C to 400 °C, and the results were also analysed for thermal variation coefficients. A decline in magnetic properties with increasing temperature was noted. At 400 °C, the magnetic induction is reduced by 0.03%, the coercivity by 0.018% and the energy product decreased by 0.12% per kelvin.