POROUS MULLITE CERAMIC COMPOSITES WITH NEEDLE-LIKE MICROSTRUCTURE AND ZIRCONIA GRAINS. PROCESSING AND PROPERTIES.

PAULA LOPEZ; ANABELLA MOCCIARO; M. FLORENCIA HERNANDEZ; DIEGO RICHARD; NICOLÁS R. RENDTORFF

Florianopolis

Congreso; 67 Congreso de Ceramica Brasilero; 2023

Asociación de Ceramica Brasilera

This work describes the effect of incorporating stabilized zirconia in ceramic composites based on acicular mullite (3Al2O3.2SiO2), produced by ceramic processing. The acicular grains of mullite, being defect-free single crystals, act as reinforcement. This needle microstructure was favored by a molybdenum oxide (MoO3) precursor additive. The obtained novel composite presents a well-defined and consolidated homogeneous microstructure, with mullite needle-shaped grains and well dispersed zirconia sub-micron grains. Mullite grains have high aspect ratio above 12:1, being their diameters below 1 micron. On the other hand, zirconia grains present diameters similar to those of the starting material. The effect of zirconia on the formation and growth mechanisms of mullite needles was not significant. Although the ceramic products present high porosities, an enhancement (17 %) of the mechanical properties was obtained. These results encourage further investigations to establish novel material design strategies at the microscale by tuning the initial formulation.