Abstract

A novel method is employed for the formation of rare earth phosphate solid solution compounds with unique mesoscopic structures. Europium- And lanthanum-doped sodium borate glass microspheres and particles, ranging in sizes from 50 to 300 μm, were reacted in 0.25 M K2HPO4 solution to form hollow spheres of nanocrystalline rare earth phosphate compounds by dissolution-precipitation reactions. The initially X-ray amorphous precipitated rare earth phosphate materials were heat-treated at 700°C for 2 h to form nanocrystalline compounds. Differential thermal analysis (DTA) experiments yield an average activation energy for crystallization of 394 ± 26 kJ/mol. X-ray diffraction (XRD) data indicate that samples crystallized to the monazite structure (monoclinic P21/n) with unit cell volumes ranging from 306.5 Å3 for LaPO4 to 282.5 Å3 for EuPO4 and with crystallite grain sizes of 56 ± 14 nm. Compositions containing both rare earth elements formed solid solutions with the composition La(1-x) EuxPO4. Raman spectroscopy indicates that the P-O symmetric stretching vibrations (ν1) change systematically from 963 cm-1 for LaPO4 to 986 cm-1 for EuPO4, consistent with a systematic decrease in average P-O bond length. Photoluminescence measurements show maximum emission intensity for the La0.65Eu0.35PO4 composition. © 2014 The American Ceramic Society.

Department(s)

Materials Science and Engineering

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Full Access

Comments

National Science Foundation, Grant DMR-0305202

International Standard Serial Number (ISSN)

1551-2916; 0002-7820

Document Type

Article - Journal

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Citation

File Type

text

Language(s)

English

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© 2024 Wiley, All rights reserved.

Publication Date

01 Jan 2014

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