Model
Digital Document
Publisher
Florida Atlantic University
Description
Raman spectroscopy was used to investigate how phase structure and phase stability of zirconia mixtures depend on temperature, type and concentration of added rare earth oxides, and fabrication process. All 8wt% yttria samples exhibited the tetragonal structure between 300 and 10 K. The TZP sample, prepared under pressure and fully hardened, exhibited the most completely stabilized tetragonal structure. The plasma coating process did not improve the stability of the tetragonal structure. Adding ceria to zirconia did not completely stabilize the tetragonal structure, while adding alumina actually destabilized it. Mode Gruneisen parameters, obtained from changes in frequency for yttria samples with different concentration, agreed with published results under pressure, except for one Eg mode. The negative value obtained for this mode was ascribed to changes in cation-anion interactions. The temperature dependence of the linewidth for this mode was quantitatively explained by cubic anharmonic interactions.
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