The chrystallografic structures of both oxides zirconia and alumina, can be different upon their composition and the processing route. In this work, zirconia-ytria / pseudobohemite (seeded whith alpha-alumina) composites, with different compositions were formulated. The initial powders were put on suspension and those suspensions were spray dried at optimized conditions [1]. After that, they were calcined at 1200ºC for 1 hour, to transform the original pseudoboehmite into alpha-Al 2 O 3 and

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... nent monoclinic-zirconia the into tetragonal-zirconia. The results shown in figures 1 and 2, correspond to the 100% alumina and 85% alumina samples, respectively. Those samples are representative of the chrystallografic phases found in the other composites. In these, the pseudobohemite presented a serie of transformations during the thermal treatment [2]. The figures 1a and 1b correspond to the pure alumina sample, they show a diffraction pattern and a high resolution TEM image, respectively. The figures 2a, 2b and 2c show a tetragonal zirconia diffraction pattern, a monoclinic zirconia diffraction pattern and a high resolution TEM image from a monocrinic grain, respectively. A. (2 0 -2 ) B. ( 0 1 4 ) C. ( 2 1 2 ) A. ( 0 0 2 ) B. ( 1 1 0 ) C. ( 1 1 2 ) A. ( 0 1-1 ) B. ( 0 1 1 ) C. ( 0 2 0 )