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Zr
O
Otobe, Haruyoshi; Nakamura, Akio; Yamashita, Toshiyuki; Minato, Kazuo
Journal of Physics and Chemistry of Solids, 66(2-4), p.329 - 334, 2005/02
Times Cited Count:24 Percentile:65.88(Chemistry, Multidisciplinary)Pyrochlore-type (P-type) zirconias have been attracting significant research interest as disposable forms of high-level radioactive waste. In this work, we have clarified the oxygen potentials (g(O
)) vs. oxygen nonstoichiometry (x) and temperature relations of P-type Ce
Zr
O
by the emf method and determined the lattice parameters (a0) with respect to x by XRD method.
M
O
7(M=Pu, Ce) by EMF methodOtobe, Haruyoshi; Nakamura, Akio; Yamashita, Toshiyuki; Ogawa, Toru
Journal of Nuclear Science and Technology, 39(Suppl.3), p.652 - 655, 2002/11
Pyrochlore-type (P-type) zirconia has been widely studied as a disposable form of the high-level radioactive nuclear waste. We have developed the EMF (electromotive force) measurement system using the cubic zirconia sensor, in order to investigate the oxygen potential (
g(O
)) of P-type Zr
Pu(Ce)
O
. For P-type Zr
Ce
O
at 1078 K, we have found that
g(O
) vs. oxygen composition (x) relationship has different behavior between x more than 0.34 and x less than 0.34. This may suggest that the degree and way of the ordering of oxide ions (O
) and oxygen vacancies (V0) should change around x =0.34. We have also measured the
g(O
) vs. temperature (T) relationship between 763 and 1078 K at various x, and derived the partial molar enthalpy (h(O
)) and entropy (s(O
)) of oxygen. It was found that h(O
) and s(O
) of P-type Zr
Ce
O
exhibit significantly different behavior from those of fluorite-type CeO
. The similar experiments are in progress for P-type Zr
Pu
O
, and the results are discussed in comparison with those of P-type Zr
Ce
O
mentioned above.