Determination of particle size distribution in an Fe sub 2 O sub 3 -based catalyst using magnetometry and x-ray diffraction

Journal Article · Wed Jul 01 04:00:00 EDT 1992 · Journal of Materials Research; (United States)

DOI:https://doi.org/10.1557/JMR.1992.1856· OSTI ID:7068295

Ibrahim, M M; Zhao, J; Seehra, M S ^[1]

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1. Physics Department, West Virginia University, Morgantown, West Virginia 26506 (United States)

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 {alpha}--Fe{sub 2}O{sub 3} based catalyst. After determining the region of superparamagnetism, the distribution function {ital f} ({ital 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 A and range of 35 to 115 A. From line-broadening of Bragg peaks in x-ray diffraction, particle radii varying between 75 A and 110 A are obtained. These results are compared with the reported Moessbauer measurements of Huffman {ital et} {ital al}. on the same sample.

• DOE Contract Number: FC22-90PC90029
• OSTI ID: 7068295
• Journal Information: Journal of Materials Research; (United States), Journal Name: Journal of Materials Research; (United States) Vol. 7:7; ISSN JMREE; ISSN 0884-2914
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
CATALYSTS
CHALCOGENIDES
COHERENT SCATTERING
DIFFRACTION
ELECTRONIC EQUIPMENT
EQUIPMENT
FLUXMETERS
IRON COMPOUNDS
IRON OXIDES
LINE BROADENING
MAGNETIZATION
MEASURING INSTRUMENTS
MICROWAVE EQUIPMENT
OXIDES
OXYGEN COMPOUNDS
PARTICLE SIZE
PARTICLES
SCATTERING
SIZE
SQUID DEVICES
SUPERCONDUCTING DEVICES
TEMPERATURE RANGE
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
TRANSITION ELEMENT COMPOUNDS
X-RAY DIFFRACTION