High brittleness severely restricts the practical use of nanocrystalline cores in low-frequency power electronics. To enhance mechanical strength and facilitate cutting and transportation, curing techniques are commonly employed, yet their influence on the magnetic properties of the cores remains unclear. In this work, three curing techniques, namely, fluid-phase adhesive curing, gel-phase adhesive curing, and vacuum-evacuated gel-phase adhesive curing (VGAC), are applied to prepare cores with varying curing degrees. The magnetic properties of them are quantitatively compared with those of uncured cores within the range of 50–550 Hz. Results show that all three curing techniques demonstrably reduce the eddy current losses of the cores. Specifically, the VGAC-based core exhibits a 50% reduction in eddy current loss compared to the uncured core at 550 Hz and 0.8 T. Meanwhile, high saturation flux density is retained in all cured samples. However, curing also reduces permeability and raises coercivity. Furthermore, cured cores demonstrate increased hysteresis and residual losses, leading to higher total losses. The relationship between core losses and temperature rise is also investigated to provide important guidance for the safe operation of cured cores. In addition, microscopic images under 200× magnification are presented to elucidate the mechanisms underlying these observed influences.
Wang et al. (Tue,) studied this question.