Effects of Si on the microstructure, soft magnetic properties and bendability of rapidly-annealed nanocrystalline Fe-Si-B-P-Cu alloy ribbons

The high Fe-content Fe-Si-B-P-Cu nanocrystalline alloys obtained by annealing the amorphous/nano-crystalline precursors are brittle and their magnetic properties are sensitive to the annealing process, which are disadvantageous for the practical applications of the alloys. In this study, the effects of Si on micro-structure, soft magnetic properties and bendability of the rapidly-annealed Fe83SixB14-xP2Cu1 (x = 2-6 at%) nanocrystalline ribbons were investigated, and the properties of the nanocrystalline alloys with different Si contents were discussed in correlation to the structural evolution and element distribution. It was found that the partial substitution B with Si in the Fe-Si-B-P-Cu alloy system could promote the primary crys-tallization of alpha-Fe(Si) grains and suppress the precipitation of the hard-magnetic Fe-metalloid phase, thus widening the optimum annealing temperature (Top) ranges for preparing the alloys with high saturation magnetization (Bs) and low coercivity (Hc). The alloys rapidly annealed at Top for 30 s possess fine and uniform amorphous/alpha-Fe(Si) nanocrystalline structure, and exhibit good soft magnetic properties including high Bs of 1.80-1.85 T and low Hc of 5.2-7.2 A/m. Furthermore, the atom probe tomography (APT) results indicated that the distribution of Si in the nanocrystalline alloys is more uniform than that of B. The sub-stitution of B with Si could decrease the compositional inhomogeneity, contributing to an improvement of bendability for the alloys with higher Si contents.(c) 2023 Elsevier B.V. All rights reserved.

Automated summary

The effects of Si on the microstructure, soft magnetic properties, and bendability of rapidly-annealed Fe83SixB14-xP2Cu1 nanocrystalline ribbons were investigated. The substitution of B with Si promoted the formation of alpha-Fe(Si) grains and suppressed the precipitation of the hard-magnetic phase, resulting in a wider annealing temperature range for preparing alloys with high saturation magnetization and low coercivity. The alloys with higher Si contents exhibited improved bendability due to a more uniform distribution of Si compared to B.