Influence of addition of polysiloxane on sintering

Abstract

The effects of adding polysiloxane (polymethylsilsesquioxane) on the sintering behavior, microstructure and hardness of alumina ceramics have been studied. The sintering kinetics of coldpressed specimens was studied by dilatometry. Polymer sintering aid was used for alumina based ceramics sintered at 1650º C. The sintered materials were characterized using helium picnometry, x-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, energy dispersive x-ray spectrometry and Vickers indentation. The addition of polymethylsilsesquioxane yielded alumina/Si2Al4O4N4 composites. The sintering studies in nitrogen atmosphere (1650 °C/1h) revealed that the highest densities were obtained for specimens with 1wt% PMS. The materials prepared with ceramic polymer precursors had higher hardness than the standard specimen. The preparation of ceramic composites using small amounts of polymer precursors is suited for alumina based ceramics. The processing route being simple, it has the potential to enable the manufacture of complex shaped pieces.