Formation at low temperature with low shrinkage of polymer/Al/Al2O3 derived mullite

The active filler controlled pyrolysis of polymer has been used to synthesize mullite from Al/Al2O3-filled siloxane. This monolith has been compared to mullite synthesized in the same conditions from Al-filled and Al2O3-filled siloxanes. Due to the presence of transition alumina and to a finer scale of mixing of the mullite precursors provided from the active Al-filler, the initial mullitization temperature was lowered in the two first systems (1200–1250°C) in comparison to the last one (1400°C). However, the improved microstructure obtained with the Al/Al2O3-filled mixture indicates that this system has advantages of low temperature and shrinkage, and low defect mullite, in comparison to mullite obtained from Al-filled and Al2O3-filled siloxanes.