Regular Fe3O4 octahedrons with excellent soft magnetic properties prepared by dealloying technique

•Regular Fe3O4 octahedrons was successfully fabricated by dealloying technique.•Dealloying factors were compared and optimized to obtain Fe3O4 octahedrons.•The presently prepared Fe3O4 octahedrons revealed good magnetic properties.•The Fe3O4 octahedrons exhibited a promising application prospect.

The dealloying processes of Al–15Fe (at.%) alloy ribbons consisting of two distinct phases of α-Al (Fe) and Al13Fe4 in NaOH solutions were investigated. The effects of NaOH solution concentration, dealloying temperature and time on the results were comparatively discussed. The as-dealloyed samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). It was found that all of the three experimental conditions could affect the morphology of the as-dealloyed samples, and the influence of solution concentration was the crucial factor. The Al could be leached out from both the α-Al (Fe) and Al13Fe4 phases to obtain regular octahedral Fe3O4 under most of the experimental conditions except for that in the 0.5 mol L−1 NaOH solution at ambient temperature. In particular, the Fe3O4 from dealloying Al–15Fe ribbons in 5 mol L−1 NaOH solution for 48 h at ambient temperature shows a uniform octahedral structure (average edge length: 667 ± 158 nm) and special magnetic properties (saturation magnetization: 83.3 emu g−1, residual magnetization: 10.4 emu g−1 and coercive force: 256.9 Oe), implying its potential applications in magnetic fluid, information storage, etc.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide