A new method for the identification and quantification of magnetite–maghemite mixture using conventional X-ray diffraction technique

The electrical explosion of Fe wire in air produced nanoparticles containing the binary mixture of magnetite (Fe3O4) and maghemite (γ-Fe2O3). The phase identification of magnetite and maghemite by the conventional X-ray diffraction method is not a simple matter because both have the same cubic structure and their lattice parameters are almost identical. Here, we propose a convenient method to assess the presence of magnetite–maghemite mixture and to further quantify its phase composition using the conventional peak deconvolution technique. A careful step scan around the high-angle peaks as (5 1 1) and (4 4 0) revealed the clear doublets indicative of the mixture phases. The quantitative analysis of the mixture phase was carried out by constructing a calibration curve using the pure magnetite and maghemite powders commercially available. The correlation coefficients, R2, for magnetite–maghemite mixture was 0.9941. According to the method, the iron oxide nanoparticles prepared by the wire explosion in this study was calculated to contain 55.8 wt.% maghemite and 44.2 wt.% magnetite. We believe that the proposed method would be a convenient tool for the study of the magnetite–maghemite mixture which otherwise requires highly sophisticated equipments and techniques.

► A simple method is presented for the fast identification and quantification of magnetite–maghemite mixture.
► The iron oxide nanoparticles produced by electrical wire explosion contained 55.8 wt.% maghemite and 44.2 wt.% magnetite.
► The method is expected to be extended to other binary mixture systems whose lattice parameters are very close.