Thermal treatment of magnetite nanoparticles.

Beata Kalska-Szostko,Per Nordblad,Dariusz Satula,Urszula Wykowska

doi:10.3762/bjnano.6.143

Beata Kalska-Szostko, Per Nordblad + Show 2 more

Open Access

https://doi.org/10.3762/bjnano.6.143

Copy DOI

Abstract

This paper presents the results of a thermal treatment process for magnetite nanoparticles in the temperature range of 50–500 °C. The tested magnetite nanoparticles were synthesized using three different methods that resulted in nanoparticles with different surface characteristics and crystallinity, which in turn, was reflected in their thermal durability. The particles were obtained by coprecipitation from Fe chlorides and decomposition of an Fe(acac)3 complex with and without a core–shell structure. Three types of ferrite nanoparticles were produced and their thermal stability properties were compared. In this study, two sets of unmodified magnetite nanoparticles were used where crystallinity was as determinant of the series. For the third type of particles, a Ag shell was added. By comparing the coated and uncoated particles, the influence of the metallic layer on the thermal stability of the nanoparticles was tested. Before and after heat treatment, the nanoparticles were examined using transmission electron microscopy, IR spectroscopy, differential scanning calorimetry, X-ray diffraction and Mössbauer spectroscopy. Based on the obtained results, it was observed that the fabrication methods determine, to some extent, the sensitivity of the nanoparticles to external factors.

Highlights

Nanostructured magnetite has become one of the most investigated materials due to its unusual magnetic properties
The obtained nanoparticles were thermally treated in an oven in the temperature range 50–500 °C for 24 h with a temperature step of 50 °C
The performed experiments show that thermal stability of magnetite nanoparticles is dependent on the fabrication procedure

Summary

Introduction

Nanostructured magnetite has become one of the most investigated materials due to its unusual magnetic properties. For the MNP-2 particles, a more rapid change in color was observed, accompanied by a drastic decrease of the powder weight in the temperature range 200–300 °C. For the MNP-3 series, the appearance of the particles after heating is the most different from the as-prepared case but the size and shape of the structures are maintained.

Results

Conclusion