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Determination of particle size distribution in an Fe2O3-based catalyst using magnetometry and x-ray diffraction

Published online by Cambridge University Press:  31 January 2011

Manjula M. Ibrahim ,
Jianmin Zhao  and
Mohindar S. Seehra
Manjula M. Ibrahim
Affiliation:
Physics Department, West Virginia University, Morgantown, West Virginia 26506
Jianmin Zhao
Affiliation:
Physics Department, West Virginia University, Morgantown, West Virginia 26506
Mohindar S. Seehra*
Affiliation:
Physics Department, West Virginia University, Morgantown, West Virginia 26506
*
a)Author to whom correspondence should be addressed.
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Abstract

In this paper, the techniques of SQUID magnetometry and line broadening in x-ray diffraction are employed for determining an important parameter for catalysts, viz. the particle size distribution. Magnetization versus temperature (5 K–400 K) and magnetization versus field (up to 55 kOe) data are reported for an α–Fe2O3 based catalyst. After determining the region of superparamagnetism, the distribution function f(r) is determined assuming a log normal distribution and Langevin paramagnetism of superparamagnetic particles. The distribution is found to be fairly symmetric with center near 65 Å and range of 35 to 115 Å. From line-broadening of Bragg peaks in x-ray diffraction, particle radii varying between 75 Å and 110 Å are obtained. These results are compared with the reported Mössbauer measurements of Huffman et al. on the same sample.

Type
Articles
Information
Journal of Materials Research , Volume 7 , Issue 7 , July 1992 , pp. 1856 - 1860
Copyright
Copyright © Materials Research Society 1992

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