High temperature magnetic properties of 49%Co–2%V–Fe alloy

Abstract

Direct current hysteresis loops of 49%Co–2%V–Fe alloy have been measured at temperatures up to 800 °C. Two phase structure is evident in the B–H loops between 580 and 730 °C. This alloy cannot be reliably operated above 580 °C. The second magnetic phase is believed to result from the nucleation and growth of disordered α phase in the ordered α′ phase matrix. Magnetic properties (measured as B at H=2.5 and 10 Oe) degrade with time during aging at 450 °C, but approach stable values after about 1000 h, which provides the possibility for long‐term high temperature (e.g., 450 °C) operation if the degraded properties are still acceptable for the application. The coercive field remains unchanged while the permeability decreases irreversibly during aging. The irreversible magnetic property changes that occur during aging at 450 °C are most likely caused by an increase in the long range order parameter.