INFLUENCE OF MAGNETIC FIELD ON DEALLOYING OF Al-15Fe RIBBONS AND FORMATION OF Fe_3O_4 OCTAHEDRA

摘要

The dealloying behavior of Al-15Fe (at.%) ribbons in a 5 mol·L~(-1) NaOH solution under static magnetic field has been investigated. The as-dealloyed samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) analysis. The results reveal that Al atoms can be leached out from the α-Al(Fe) and Al_(13)Fe_4 phases in NaOH solutions with magnetic field, and the magnetic field can significantly reduce the particle size of the as-dealloyed samples comparing with those from non-treatment dealloying (1093 ± 202 nm). The average edge lengths of these octahedra are 303 ± 67 nm (under 0.25 T), 380 ± 141 nm (0.5 T), 421 ± 187 nm (0.75 T), respectively, implying that an optimized selection of magnetic intensity is helpful to obtain refined Fe_3O_4 particles. In addition, the particle morphology is obviously influenced by magnetic field and the effects were also systematically discussed.