Ceramic powders containing tetragonal zirconia prepared by a sol-gel route

The question of enhancing the mechanical properties of ceramics such as strength, toughness, thermal shock resistance, etc., by additions of zirconia particles in the monoclinic and/or the tetragonal form is now widely open. Among the different methods which have proved capable of dispersing and maintaining tetragonal zirconia particles in ceramic matrices, annealing of partially stabilized zirconias, reaction sintering of zircon-based powders and the mixed powder route are the best known. Other techniques are appearing and among them is the preparation of powders containing tetragonal zirconia and their further dispersion followed by consolidation in ceramic matrices. This letter describes preliminary results of the preparation of powders of composition 3Al sub(2)O sub(3) - 2SiO sub(2) - 2ZrO sub(2) (with 2 wt% MgO) containing tetragonal zirconia and obtained by densification of glasses produced by the sol - gel route.