Improvement of Soft Magnetic Properties of Fe-Si-Al Metal Powder Cores by Metallurgical Process

Considering the new applications of high power electronics for (hybrid) electric vehicles, a lot of new requirements arise for soft magnetic materials. The combination of high permeability under DC excitation (DC Bias characteristics), low core loss, good thermal stability, and low cost allows the reduction of size, weight, and price of magnetic components used in. Among the today's most relevant soft magnetic materials to high power inductors, metal alloy powder cores are good candidates. In this paper, improved experimental results of Fe-Si-Al alloy powder cores by metallurgical process are shown and discussed : Dramatic decrease of hysteresis loss of Fe-Si-Al alloy powder cores (150 mW/cc @50KHz, 0.1T) was achieved by getting lower coercive force(Hc) through the high temperature grain growth process of raw material powders. Lowest core loss and increased DC Bias characteristics are simultaneously achieved by controlling the shape of individual particles and adjusting the metallurgical alloy composition of Fe-Si-Al powders. It was found that precise metallurgical process controlling could provide the high potential of possible innovations of the inductive components.