Perturbed angular correlation investigation of zirconia ceramics
A four-detector time differential perturbed angular correlation (PAC) spectrometer was built and has been used to characterize phases and study local properties and defect dynamics of pure zirconia, yttria-stabilized cubic zirconia, and yttria partially stabilized zirconia (Y-PSZ). The PAC spectra of pure zirconia were characterized by discrete frequencies. The electric field gradient (EFG) magnitude, the asymmetry parameter, and the EFG distribution were determined from the spectra by a least-square fitting procedure. The EFG in the monoclinic and tetragonal phase is weakly temperature-dependent and in larger in the tetragonal phase. The EFG was calculated using a point-ion charge model. The results agree qualitatively with the experimental data, but the calculated EFG magnitudes were typically 40-50% smaller than the experimental field gradients. PAC spectra in cubic stabilized zirconia are characterized by a wide frequency distribution. While spectra at highest and lowest temperatures are static, the spectra in the intermediate temperature range show relaxation phenomena arising from oxygen vacancy diffusion. PAC spectra in Y-PSZ show two components, one tetragonal-like, the other cubic-like. From a least-squares fitting procedure the phase boundary between the cubic and tetragonal-cubic mixed region was determined.
- Research Organization:
- Oregon State Univ., Corvallis (USA)
- OSTI ID:
- 6977997
- Country of Publication:
- United States
- Language:
- English
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ANGULAR CORRELATION
CHALCOGENIDES
CORRELATIONS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ELECTRIC FIELDS
HIGH TEMPERATURE
METALLURGICAL EFFECTS
OXIDES
OXYGEN COMPOUNDS
PERTURBED ANGULAR CORRELATION
PHASE STUDIES
SPECTRA
STABILIZATION
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES