Mullite/Zirconia Nanocomposites from a Preceramic Polymer and Nanosized Fillers

摘要

A novel methodology for the production of mullite/zirconia nanocomposites is proposed, starting from a mixture of a preceramic polymer containing y-A1_2O_3 and ZrO_2 nanosized powders as fillers. After heat treatment at 1350℃ in air crack-free monoliths with nanometric grain size for both matrix and reinforcement phase were obtained. Different commercial ZrO_2 nanosized powders were tested, and indentation tests showed a remarkable increase of toughness due to a very effective transformation-toughening mechanism. Moreover, the additional introduction of a small quantity of TiO_2 nanosized powder led to an increase in density of the nanocomposites at relatively low sintering temperature.