The pyrochlore to ‘defect fluorite’ transition in the Y2(ZryTi1−y)2O7 system and its underlying crystal chemistry

Liu, Yun; Withers, Raymond; Norén, Lasse

doi:10.1016/j.jssc.2004.09.014

Cited by 62 publications

(51 citation statements)

References 23 publications

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“…1). The width of the P + F two-phase field along the 50Y isoconcentrate is in good agreement with the compositions reported by Liu et al 44 for a sample of 20Ti-50Y-30Zr equilibrated at 1350 • C, i.e. 23Ti-50Y-27Zr (F) and 16Ti-50Y-34Zr (P).…”

Section: Isothermal Sections Of the Tio 2 -Yo 15 -Zro 2 Systemsupporting

confidence: 91%

Phase equilibria in the TiO2–YO1.5–ZrO2 system

Schaedler

Fabrichnaya

Levi

2008

Journal of the European Ceramic Society

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Section: Isothermal Sections Of the Tio 2 -Yo 15 -Zro 2 Systemsupporting

confidence: 91%

Phase equilibria in the TiO2–YO1.5–ZrO2 system

Schaedler

Fabrichnaya

Levi

2008

Journal of the European Ceramic Society

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“…3b, e, and f). These pairs of nodes are actually sections through rings of diffuse intensity oriented normal to the /111S* directions [24][25][26][27][28]. The magnitude of the node splitting, and hence the ring diameter, is on the order of 0.04-0.07 Å À1 normal to /111S* and appears to increase from La 0.…”

Section: Microstructure and Chemistrymentioning

confidence: 99%

Lanthanum pyrochlores and the effect of yttrium addition in the systems La2−xYxZr2O7 and La2−xYxHf2O7

Whittle

Cranswick

Redfern

et al. 2009

Journal of Solid State Chemistry

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The crystal structures of the compounds La 2Àx Y x Zr 2 O 7 and La 2Àx Y x Hf 2 O 7 with x ¼ 0.0, 0.4, 0.8, 1.2, 1.6, and 2.0 have been studied using neutron powder diffraction and electron microscopy to determine the stability fields of the pyrochlore and fluorite solid solutions. The limits of pyrochlore stability in these solid solutions are found to be close to La 0.8 Y 1.2 Zr 2 O 7 and La 0.4 Y 1.6 Hf 2 O 7 , respectively. In both systems the unit cell parameter is found to vary linearly with Y content across those compositions where the pyrochlore phase is stable, as does the x-coordinate of the oxygen atoms on the 48f (x, 3 8 , 3 8 ) sites. In both systems, linear extrapolations of the pyrochlore data suggest that the disordering is accompanied by a small decrease in the lattice parameter of approximately 0.4%. After the pyrochlore solid solution limit is reached, a sharp change is observed from x$0.41 to 0.375 as the disordered defect fluorite structure is favoured. Electron diffraction patterns illustrate that some short-range order remains in the disordered defect fluorite phases.

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“…The loss of cation and anion ordering during the pyrochlore to fluorite transformation could be a reason for the low swelling observed for the pyrochlore samples. The rare earth zirconia pyrochlore lattice has a lower density than the REE stabilised zirconia with (defect) fluorite structure [11,29]. Therefore, the swelling induced by self-radiation might be compensated by the concomitant densification caused by the loss in cation and anion ordering.…”

Section: Self-irradiation Effects On Crystal Structurementioning

confidence: 99%