Articulo
On the occurrence of a metastable tetragonal t′-phase in a ZrO<SUB>2</SUB> −13.6 mole % MgO ceramic and its microscopic thermal evolution
Registro en:
issn:0884-2914
issn:2044-5326
Autor
Caracoche, María Cristina
Rivas, Patricia Claudia
Pasquevich, Alberto Felipe
López García, Alberto Raúl
Aglietti, Esteban Fausto
Scian, Alberto Néstor
Institución
Resumen
The time-differential perturbed angular correlation technique has been used to investigate the thermal behavior of a ZrO 2 −13.6 mole % MgO ceramic between room temperature and 1423 K. Two different quadrupole hyperfine interactions corresponding to a tetragonal structure have been found to result on cooling the ceramic from the single-phase cubic field. One of them agrees with that depicting the pure t -ZrO 2 tetragonal phase and the other one has been interpreted as describing a high-MgO-content nontransformable t '–ZrO 2 phase. As temperature increases, the latter gives rise to a similar but fluctuating interaction related to the oxygen vacancies mobility and which shows a thermal behavior analogous to that already reported for the stabilized cubic ZrO 2 . Above 1100 K these dynamic t '-sites transform into pure tetragonal ones which behave ordinarily, suffering the t → m phase transition when cooling to room temperature. Differences found between TDPAC results and information drawn from other techniques are discussed. Facultad de Ciencias Exactas Centro de Tecnología de Recursos Minerales y Cerámica