Studies of crystallization and soft magnetic properties of FeNiMoB(Si) alloys

Abstract

Crystallization behaviors of Fe 40Ni 38Mo 4B 18, Fe 38Ni 35Mo 4Si 5B 18, and Fe 39Ni 36Mo 2Si 5B 18 (at%) amorphous alloys as well as magnetic properties of the Fe 40Ni 38Mo 4B 18 alloy, annealed in the temperature range from 400 to 520 °C for 1 h, have been investigated. The results show that for the samples of Fe 40Ni 38Mo 4B 18, annealed in the temperature range of 430–450 °C, a single-crystalline FCC phase with composition near Ni 3Fe solid solution and grain size of about 10 nm precipitates in the amorphous matrix, and the samples exhibit good soft magnetic properties. As the samples are annealed at T a⩾470 °C, the magnetic properties drop rapidly, this is mainly due to the formation of Fe–B and Ni–B compounds. For the samples of Fe 38Ni 35Mo 4Si 5B 18 and Fe 39Ni 36Mo 2Si 5B 18, a single FCC crystalline phase structure cannot be formed in the amorphous matrix, where more than single-crystalline phase such as Fe–B compounds as well as γ-(Fe, Ni) phase are precipitated almost simultaneously by the annealing treatment.