Transformation of yttrium-doped hydrated zirconium into tetragonal and cubic nanocrystalline zirconia
- National Univ. of Mexico (Mexico). Inst. of Physics
- National Polytechnic Inst., Mexico Distrito Federal (Mexico)
- Inframat Corp., North Haven, CT (United States)
- Univ. of Connecticut, Storrs, CT (United States). Precision Mfg. Center
Nanostructured yttrium-stabilized zirconia powders, with yttria concentrations between 0.0 and 10.0 mol%, were prepared via the hydrolysis of an aqueous solution of zirconyl and yttrium chloride, and ammonium hydroxide. Powder phases were characterized by using X-ray powder diffraction; their crystalline structures were refined with the Rietveld technique. When samples were annealed below 200 C, their diffraction patterns corresponded to an amorphous atom distribution and were independent of yttria concentration. The doped amorphous phases crystallized, at 400 C, into tetragonal or cubic nanocrystalline zirconia, which were stabilized by yttrium. These results suggest that yttrium atoms served as a substitute for zirconium atoms not only in the crystalline phases but also in the amorphous phases, which are determined by the fast condensation of zirconyl clusters. Nondoped samples contained a mixture of monoclinic and tetragonal nanocrystalline zirconia; those with 2.5 to 5.0 mol% yttria contained only the tetragonal zirconia nanophase, and those with 7.5 to 10.0 mol% had only the nanocrystalline cubic phase. The average crystallite size of the nanophases diminished when Y{sub 2}O{sub 3} concentration was increased.
- OSTI ID:
- 329188
- Journal Information:
- Journal of Solid State Chemistry, Vol. 142, Issue 2; Other Information: PBD: 1 Feb 1999
- Country of Publication:
- United States
- Language:
- English
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