Phase structure and heating efficiency of as-synthesised iron-oxide nanoparticles and after long time storage in glycerol

Abstract

In the present work the structural characteristics and heating efficiencies of iron-oxide nanoparticles were studied. The investigated samples were produced by co-precipitation of Fe–O nanoparticles from mixture of Fe2+ and Fe3+ salts in the alkaline environment. Furthermore, the influence of processing route and storage environment on the phase structure and heating efficiency was studies for glycol dispersed nanoparticles. The heating efficiency experiments were performed on 5 wt% glycerol dispersions of Fe–O nanoparticles. The measurements were carried out on specimens directly after precipitation and for those kept in glycerol for substantial period of time in order to determine how the storage environment can impact their performance as a heating medium. Furthermore, comparative studies for nanoparticles produced at different processing routes were performed. The structural studies were carried out using X-ray diffractometry and transmission electron microscopy. The heating efficiencies and specific loss powers were determined using the self-constructed setup operating in the alternating magnetic field of various amplitudes from 2 to 4 kA/m and frequency of 100 kHz.