Novel FePBNbCr glassy alloys “ SENNTIX” with good soft-magnetic properties for high efficiency commercial inductor cores

Abstract

According to a recent study, Fe-based glassy alloys are expected good soft-magnetic properties such as high saturation magnetization and lower coercive force. We focused on Fe-based glassy alloys and have succeeded in developing novel glassy Fe 97− x− y P x B y Nb 2Cr 1 ( x = 5–13, y = 7–15) alloys for an inductor material. The glassy alloy series of Fe 97− x− y P x B y Nb 2Cr 1 ( x = 5–13, y = 7–15) have high glass-forming ability with the large critical thickness of 110–150 μm and high B s of 1.25–1.35 T. The glassy alloy powder with chemical composition Fe 77P 10.5B 9.5Nb 2Cr 1 exhibits an excellent spherical particle shape related to the lower melting point and liquid phase point. In addition, Fe–P–B–Nb–Cr powder/resin composite core has much lower core loss of 653–881 kW/m 3, which is approximately 1/3 lower than the conventional amorphous Fe–Si–B–Cr powder/resin composite core and 1/4 lower than the conventional crystalline Fe–Si–Cr powder/resin composite core due to the lower coercive force of 2.5–3.1 A/m. Based on above results, the glassy Fe 77P 10.5B 9.5Nb 2Cr 1 alloy powder enable to achieve ultra-high efficient and high quality products in a commercial inductor. In fact, the surface mounted inductor using Fe–P–B–Nb–Cr powder/resin exhibits the high efficiency of approximately 2.0% compared with the conventional inductors made of the crystalline Fe–Si–Cr powder/resin composite core.