TY - JOUR
T1 - Oxygen diffusion in niobia-doped zirconia as surrogate for oxide film on Zr-Nb alloy
T2 - AC impedance analysis
AU - Yamana, Teppei
AU - Arima, Tatsumi
AU - Yoshihara, Takatoshi
AU - Inagaki, Yaohiro
AU - Idemitsu, Kazuya
PY - 2013
Y1 - 2013
N2 - The oxygen conductivities and crystallographic properties of niobia-doped yttria-stabilized tetragonal zirconia with 0.0-2.6 wt% Nb2O 5 were evaluated by the AC impedance analysis and the X-ray diffraction measurement, respectively. The tetragonality of zirconia increased with niobia content and approached ∼1.017 while the tetragonal-to-monoclinic phase transition occurred above ca. 1 wt% Nb2O5. On the other hand, oxygen conductivities of bulk and grain-boundary (GB) decreased with increasing niobia content. The bulk conductivity controlled the total ionic conductivity at high temperatures, and its activation energy had smaller dependence on temperature than that of GB. In addition to the effect of [VO] depletion by niobia addition, the behaviors of bulk and GB conductivities might be explained by the decrease of mobility of oxygen ion due to Coulomb repulsion between Nb5+ and VO and by no segregation of Nb ions in the space-charge layers, respectively.
AB - The oxygen conductivities and crystallographic properties of niobia-doped yttria-stabilized tetragonal zirconia with 0.0-2.6 wt% Nb2O 5 were evaluated by the AC impedance analysis and the X-ray diffraction measurement, respectively. The tetragonality of zirconia increased with niobia content and approached ∼1.017 while the tetragonal-to-monoclinic phase transition occurred above ca. 1 wt% Nb2O5. On the other hand, oxygen conductivities of bulk and grain-boundary (GB) decreased with increasing niobia content. The bulk conductivity controlled the total ionic conductivity at high temperatures, and its activation energy had smaller dependence on temperature than that of GB. In addition to the effect of [VO] depletion by niobia addition, the behaviors of bulk and GB conductivities might be explained by the decrease of mobility of oxygen ion due to Coulomb repulsion between Nb5+ and VO and by no segregation of Nb ions in the space-charge layers, respectively.
UR - http://www.scopus.com/inward/record.url?scp=84888302337&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84888302337&partnerID=8YFLogxK
U2 - 10.1016/j.jnucmat.2013.10.015
DO - 10.1016/j.jnucmat.2013.10.015
M3 - Article
AN - SCOPUS:84888302337
SN - 0022-3115
VL - 443
SP - 608
EP - 613
JO - Journal of Nuclear Materials
JF - Journal of Nuclear Materials
IS - 1-3
ER -