Degradation yttria stabilized zirconia

It is said that the yttria-stabilized zirconia (Y-TZP) generally used will degrade if it remains for a long period of time under low-temperature and moist conditions, such as in the human body. Indeed, Piconi et al. have reported on a case of fracture of an artificial hip joint made of Y-TZP. 

Hauch A, Ebbesen SD, Jensen SH, Mogensen M (2008) Solid oxide electrolysis cells microstructure and degradation of the Ni/yttria-stabilized zirconia electrode. JElectrochem Soc 155(11) B1184—B1193... 

A recent study (Osenbach et al., 1997) of the reliability of InP-based diode lasers in non-hermetic conditions has shown that the commonly used facet coating layer, yttria-stabilized zirconia (YSZ), degrades in the presence of water vapor. In a typical experiment with lasers operating under conditions of 85 °C and 90% RH, the lasers failed with a median life of less than 1000 h. In this study, the median life of these lasers was determined as a function of RH and temperature, so that acceleration factors for these parameters could be determined. Application of these acceleration factors indicated that the median life in a test at 85 °C and 90% RH must be at least 3000 h to meet the field reliability expected by telecommunications providers. Thus, typical lasers used in hermetic packages do not have sufficient reliability for non-hermetic applications. 

H. Mitsuyasu, Y. Nonaka, K. Eguchi, Analysis on Solid State Reaction at the Interface of Yttria-Doped Ceria/Yttria-Stabilized Zirconia, Solid State Ionics 113-115,279-284 (1998) N. Sakai, H. Kishimoto, K. Yamaji, T. Horita, M.E. Brito, H. Yokokawa, Degradation Behavior at Interface of LSCF Cathodes and Rare Earth Doped Ceria, SOFC X, ECS Transactions, 7(1) 389-398 (2007)... 

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