(393an) Reactive Synthesis of Rare Earth-Based Nanostructured Materials

Rare earth-based nanostructured materials were manufactured using sonolytic synthesis techniques. When specifically considering the application of bimetallic nanomaterials, additional design considerations included the control of relative metal compositions and requirements of production consistency regarding the layering of active metal on the surfaces of the nanomaterials. All nanostructured materials were characterized using x-ray diffraction (XRD), elemental analysis, BET surface area analysis, scanning and transmission electron microscopies (SEM and TEM) and superconducting quantum interference device (SQUID) magnetometric analysis. Morphology and crystallite sizes were affected by the chemical composition of the synthesis mixture and also upon the sequence of NH₃OH addition to the metal chloride solutions. The majority of interesting structural morphologies were formed in Mg/Ca, Mg/Fe, Mg/Ca mixtures and CaCO₃.  The morphology of CaCO₃ precipitated microstructures indicated a dependence upon the presence of NH₃OH. When NH₃OH was included to the reaction mixture prior to sonication, CaCO₃ microcubics were produced. Conversely, the addition of NH₃OH after sonication was observed to produce CaCO₃ microdiscoids.  Mg/Ca mixtures were observed to form nanorods.  Mg/Fe mixtures were observed to produce flower-like peddles. Crystallite sizes were observed to range from 5.92 to 72.13 nm.