On the nature of the nanospikes obtained in the sonication of a molten mixture of bismuth and indium under silicone oil

A molten mixture of bismuth and indium, immersed in hot silicone oil, was dispersed into nano- and micro spheres under ultrasonic irradiation. Examination of the composition of these spheres by X-ray diffraction and Rietveld refinement revealed that they were composed of intermetallic compounds, mainly BiIn and BiIn2. TEM and SEM images showed that the surface of the spheres was covered with tiny spikes. Their chemical composition, as determined by EDS and electron diffraction, was found to be In2O3. We assume that upon formation they were composed of In, which was oxidized when exposed to air. (C) 2016 Elsevier B.V. All rights reserved.