Thermally stimulated iron oxide transformations and magnetic behaviour of cerium dioxide/iron oxide reactive sorbents

• Published in: Materials characterization Vol. 120; pp. 295 - 303
• Main Authors: Luacek, J, ivotsky, O, Jiraskova, Y, Bursik, J, Janos, P
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-10-2016
• Subjects: ANNEALING; CALCINATION; Cerium oxide; CERIUM OXIDES; Dioxides; FERRITES; GRAIN SIZE; Grain size distribution; HYSTERESIS; IRON OXIDES; Magnetic parameters; MAGNETIC PROPERTIES; MAGNETIZATION; MATERIALS SCIENCE; MOESSBAUER EFFECT; MORPHOLOGY; Mössbauer spectroscopy; Oxide-nano-composites; Phase composition; PHASE TRANSFORMATIONS; RESOLUTION; Sorbents; TEM; TEMPERATURE RANGE 0273-0400 K; TEMPERATURE RANGE 0400-1000 K; Transformations; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION; Cerium oxide; Magnetic parameters; Oxide-nano-composites; TEM; Mössbauer spectroscopy
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2016.09.009

The present paper is devoted to detailed study of the magnetically separable sorbents based on a cerium dioxide/iron oxide composite annealed at temperatures Ta=773K, 873K, and 973K. The X-ray diffraction and high resolution transmission electron microscopy are used to determine the phase composition and microstructure morphology. Mössbauer spectroscopy at room (300K) and low (5K) temperatures has contributed to more exact identification of iron oxides and their transformations Fe3O4→γ-Fe2O3 (ε-Fe2O3)→α-Fe2O3 in dependence on calcination temperature. Different iron oxide phase compositions and grain size distributions influence the magnetic characteristics determined from the room- and low-temperature hysteresis loop measurements. The results are supported by zero-field-cooled and field-cooled magnetization measurements allowing a quantitative estimation of the grain size distribution and its effect on the iron oxide transformations.
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•Magnetically separable sorbents based on a CeO2/Fe2O3 composite were investigated.•Microstructure of sorbents was determined by XRD, TEM and Mössbauer spectroscopy.•Magnetic properties were studied by hysteresis loops at room- and low-temperatures.•Phase transitions of iron oxides with increasing annealing temperature are observed.