Raman, XRD and microscopic investigations on CeO{sub 2}-Lu{sub 2}O{sub 3} and CeO{sub 2}-Sc{sub 2}O{sub 3} systems: A sub-solidus phase evolution study

Journal Article · Fri Aug 15 04:00:00 EDT 2008 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2008.04.001· OSTI ID:21128394

Grover, V ^[1]; Banerji, Ankita ^[2]; Sengupta, P ^[3]

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1. Chemistry Division, Bhabha Atomic Research Centre, Mumbai-400 085 (India)
2. High Pressure Physics Division, Bhabha Atomic Research Centre, Mumbai-400 085 (India)
3. Material Science Division, Bhabha Atomic Research Centre, Mumbai-400 085 (India)

A sub-solidus phase evolution study was done in CeO{sub 2}-Sc{sub 2}O{sub 3} and CeO{sub 2}-Lu{sub 2}O{sub 3} systems under slow-cooled conditions from 1400 deg. C. Long-range order probing of X-ray diffraction technique is utilized in conjunction with the ability of Raman spectroscopy to detect the changes in local co-ordination. Lu{sub 2}O{sub 3} showed solubility of 30 mol% in CeO{sub 2}, thus forming an anion deficient fluorite-type (F-type) solid solution, whereas Sc{sub 2}O{sub 3} did not show any discernible solubility. A biphasic region (F+C) was unequivocally detected by Raman spectroscopy in Ce{sub 1-x}Lu{sub x}O{sub 2-x/2} (0.4{<=}x{<=}0.9) and in Ce{sub 1-x}Sc{sub x}O{sub 2-x/2} (0.1{<=}x{<=}0.9) systems. Raman spectroscopy was valuable in studying these systems since oxygen vacancies are created on doping RE{sub 2}O{sub 3} into ceria and Raman spectroscopy is very much sensitive to oxygen polarizability and local coordination. Back scattered images collected on representative compositions support the above-mentioned results. - Graphical abstract: Powder XRD and Raman spectroscopy were used in conjunction to delineate the phases present in CeO{sub 2}-Lu{sub 2}O{sub 3} and CeO{sub 2}-Sc{sub 2}O{sub 3} systems. LuO{sub 1.5} has 30 mol% miscibility, whereas Sc{sub 2}O{sub 3} has no discernible solubility in CeO{sub 2}. Raman spectroscopy clearly showed the evolution of second phase with change in concentration of the reactants thus supporting XRD data. Back scattered images obtained on representative compositions verify the results.

• OSTI ID: 21128394
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 8 Vol. 181; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CERIUM OXIDES
FLUORITE
LUTETIUM OXIDES
OXYGEN
POLARIZABILITY
RAMAN SPECTROSCOPY
SCANDIUM OXIDES
SOLID SOLUTIONS
SOLUBILITY
VACANCIES
X-RAY DIFFRACTION