Gd. Soraru et al., Development of mullite-SiC nanocomposites by pyrolysis of filled polymethylsiloxane gels, J EUR CERAM, 20(14-15), 2000, pp. 2509-2517
A modified processing route, which is based on the active filler controlled
pyrolysis technique, was followed here to form a homogeneous mullite-SiC n
anocomposite. An Al2O3-filled polymethylsiloxane was prepared by the in-sit
u formation of the SiCO network via a sol-gel process. The filled gels obta
ined in this way show an excellent machinability with conventional surface
grinding techniques. Heat treatment up to 1500 degreesC initiated crystalli
zation of mullite, which showed intragranular SiC precipitation. Based on m
icrostructure characterization in conjunction with thermal analysis, a form
ation mechanism is proposed which includes the glass transition temperature
of SiCO as well as its phase sparation into SiO2 plus nanosized SiC crysta
llites, giving rise to this new mullite-SiC nanocomposite. (C) 2000 Elsevie
r Science Ltd. All rights reserved.