Influence of Applied Electric Field on Low Temperature Degradation of Y-TZP

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J. Korean Ceram. Soc. > Volume 34(12); 1997 > Article

Journal of the Korean Ceramic Society 1997;34(12): 1254.

인가 전압이 Y-TZP의 저온열화에 미치는 영향

장주웅, 이홍림, 김대준¹, 오남식¹, 이득용²

연세대학교 세라믹공학과
¹한국과학기술연구원 세라믹스부
²대림전문대학 금속재료과

Influence of Applied Electric Field on Low Temperature Degradation of Y-TZP

ABSTRACT

Influence of applied electric field on the low temperature degradation of 3 mol% YaO3 stabilized tetragonal zirconia polycrystals(3Y-TZP) was investigated using X-ray diffractometry of specimens aged under the dc field of 1.1 kV/mm in silicone oil both of 12$0^{circ}C$-21$0^{circ}C$. After the aging, the tetragonal to monoclinic phase transformation was observed only on the specimen surface of 3Y-TZP faced to the anode. This indicated that the surface was overcrowded with oxygen ions as a result of diffusion of oxygen vacancies toward the cathode-sided surface. To elucidate an influence of the applying time of the electric field on the extent of the degradation of 3Y-TZP in air, specimens were aged fore 0-2 hours under the electric field in the oil bath of 12$0^{circ}C$ and then subsequently aged for 3h at 22$0^{circ}C$ in air. The longer the specimens were aged under the field, the more extensive the transformation to the monoclinic phase was on the specimen surface faced to the cathode, probably originated from a high diffusion rate of oxygen ions due to a steep oxygen vacancy concentration gradient.

Key words: Tetragonal zirconia, 3Y-TZP, Low temperature degradation