CHARACTERIZATION OF ZIRCONIA-TOUGHENED ALUMINA (ZTA) CERAMICS BY SEM-CATHODOLUMINESCENCE

Cathodoluminescence (CL) studies in a scanning electron microscope of zirconia-toughened alumina (ZTA) with three different zirconia contents are described. The CL spectra show a broad violet emission centered at about 3.1 eV (400 nm) and a large and complex blue-green band centered near 2.6 eV (475 nm). The former arises from alumina, whereas the latter is associated with the zirconia component. A correlation between the luminescence and the nature of monoclinic to tetragonal zirconia is found. The results are discussed on the basis of oxygen vacancies and complex defects. The effects of toughening mechanisms on the luminescence of the ZTA samples are also considered.