Oxygen Potentials of Pyrochlore-Type Am2zr2o7+Y

The relations between the oxygen potentials and the excess oxygen-nonstoichiometry (y) of the pyrochlore-type Am2Zr2O7+y at 1333 K were measured by the electrochemical method using a zirconia solid electrolyte and the change of mass by oxidation and reduction. The oxygen potentials at 1333 K smoothly increased from -516.5 to 0.00 kJ/mol with increasing y from 0.00 to 0.56. It was found that the oxygen potentials of Am2Zr2O7+y were higher than those of AmO2-x and Am0.5Np0.5O2-x measured in our previous studies at 1333 K. The results were discussed with the valence state and ionic radius of cations as well as the phase relations.