TY - GEN
T1 - Penetration of water into yttrium- and scandium-doped barium zirconate and its relation to proton conductivity
AU - Nose, Y.
AU - Okumura, Y.
AU - Imashuku, S.
AU - Suehiro, K.
AU - Uda, T.
AU - Awakura, Y.
PY - 2009
Y1 - 2009
N2 - The diffusion coefficient and amount of water in trivalent cation doped barium zirconate were investigated by thermogravimetry. The apparent diffusion coefficient of water of yttrium-doped barium zirconate which was sintered for 24 hours, Y24, was 2.9 × 10-11 m2 s-1 at 700 °C under pH2O= 0.05 atm. The diffusion coefficient is almost independent of the sintering period. This means that the diffusion coefficient is independent of the grain size. The ratio of water to oxide ion vacancy before water introduction was evaluated from weight change of water in thermogravimetry. This ratio in Y24 is about 32 % and 62 % at 600 °C and 500 °C, respectively. Electric conductivity of sintered pellets was also measured. In S24, which is scandium-doped barium zirconate sintered for 24 hours, the change of the bulk conductivity after change of the atmosphere from dry to wet was governed by the diffusion of water. It takes more than 10 hours to thermodynamically complete full hydration of the specimen in the disk with the diameter of 10 mm and thickness of 1.5 mm even at 700 °C.
AB - The diffusion coefficient and amount of water in trivalent cation doped barium zirconate were investigated by thermogravimetry. The apparent diffusion coefficient of water of yttrium-doped barium zirconate which was sintered for 24 hours, Y24, was 2.9 × 10-11 m2 s-1 at 700 °C under pH2O= 0.05 atm. The diffusion coefficient is almost independent of the sintering period. This means that the diffusion coefficient is independent of the grain size. The ratio of water to oxide ion vacancy before water introduction was evaluated from weight change of water in thermogravimetry. This ratio in Y24 is about 32 % and 62 % at 600 °C and 500 °C, respectively. Electric conductivity of sintered pellets was also measured. In S24, which is scandium-doped barium zirconate sintered for 24 hours, the change of the bulk conductivity after change of the atmosphere from dry to wet was governed by the diffusion of water. It takes more than 10 hours to thermodynamically complete full hydration of the specimen in the disk with the diameter of 10 mm and thickness of 1.5 mm even at 700 °C.
KW - Amount of water
KW - Barium zirconate
KW - Diffusion of water
KW - Perovskite-type oxide
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M3 - Conference contribution
AN - SCOPUS:77950661673
SN - 9781615674237
T3 - The Minerals, Metals and Materials Society - 3rd International Conference on Processing Materials for Properties 2008, PMP III
SP - 223
EP - 228
BT - The Minerals, Metals and Materials Society - 3rd International Conference on Processing Materials for Properties 2008, PMP III
T2 - 3rd International Conference on Processing Materials for Properties 2008, PMP III
Y2 - 7 December 2008 through 10 December 2008
ER -