Fabrication of FeSiBCr/wollastonite amorphous soft magnetic powder cores with low loss and high-quality factor

Abstract

In this paper, the best magnetic properties of FeSiBCr/wollastonite soft magnetic composites were explored by adjusting the content of wollastonite powder and annea- ling temperature. FeSiBCr/wollastonite soft magnetic composites with low loss and high quality factor were successfully prepared by adding micron-sized wollastonite po-wder into amorphous magnetic powder. Wollastonite was used as the insulating coating material of amorphous magnetic powder for the first time, which showed good performance in reducing the loss of magnetic powder. The loss change of FeSiBCr/wollastonite magnetic powder cores was studied by B-H analyzer and loss separation analysis model. The results show that the total loss (Pcv) of FeSiBCr/woll- astonite composite cores is lower than that of the pure FeSiBCr cores. With the incre- ase of wollastonite powder content and annealing temperature, the total loss of FeSiBCr/wollastonite composite powder cores shows a trend of first decreasing and then increasing. The composite powder cores containing 0.8 wt% wollastonite powder was heat treated at 678 K for 1 hour under the protection of nitrogen, and its magnetic properties were the best, with a permeability of 28.93 and a loss of 196.2 mW/cm3( f =1 MHz and Bm =20 mT). Wollastonite is a new coating material, which has a good effect of reducing loss. At the same time, this work also provides a new scheme for reducing the total loss of soft magnetic powder cores.