Mechanochemical synthesis of submicron sized Nd-Fe-B particles using planetary ball mill
ORAL
Abstract
Mechanochemical synthesis of Nd$_{2}$Fe$_{14}$B particles with size below 0.5 $\mu$m is done via planetary ball mill, followed by annealing of rare-earth oxides, iron oxide and boron oxide in the presence of a reducing agent (Ca) and a dispersant material (CaO). Compared to high energy ball mill, planetary mill gives a range in milling energy. Our purpose is to control the particle size and size distribution by changing the milling energy. In preliminary work, annealed particles in the CaO dispersant with coercivity 4.7 kOe were produced. After washing off the dispersant due to the interstitial modification of 2:14:1 phase with hydrogen, coercivity of the particles was decreased to 1.2 kOe. Electron micrographs of the samples showed that rectangular Nd$_{2}$Fe$_{14}$B particles are present with size distribution in the submicron range. The aim of this study is to obtain nanoparticles with a size below 500 nm and study the effect of size and surface on their magnetic properties. Work supported by DOE DE-FG02-04ERU612.
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Authors
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Ozlem Koylu-Alkan
Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, USA, University of Delaware
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George Hadjipanayis
Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, USA, University of Delaware, Department of Physics and Astronomy, University of Delaware, Newark, DE 19716, USA, Department of Physics and Astronomy, University of Delaware, 217 Sharp Lab, Newark, DE 19716, United States
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David Sellmyer
University of Nebraska, Univ of Nebraska - Lincoln