A modified processing route, which is based on the active filler controlled pyrolysis technique, was followed here to form a homogeneous mullite-SiC nanocomposite. An Al2O3-filled polymethylsiloxane was prepared by the in-situ formation of the SiCO network via a sol-gel process. The filled gels obtained in this way show an excellent machinability with conventional surface grinding techniques. Heat treatment up to 1500°C initiated crystallization of mullite, which showed intragranular SiC precipitation. Based on microstructure characterization in conjunction with thermal analysis, a formation mechanism is proposed which includes the glass transition temperature of SiCO as well as its phase separation into SiO2 plus nanosized SiC crystallites, giving rise to this new mullite-SiC nanocomposite.
Development of Mullite-SiC Nanocomposites by Pyrolysis of Filled Polymethylsiloxane Gels
Sorarù, Gian Domenico;Ceccato, Riccardo;
2000-01-01
Abstract
A modified processing route, which is based on the active filler controlled pyrolysis technique, was followed here to form a homogeneous mullite-SiC nanocomposite. An Al2O3-filled polymethylsiloxane was prepared by the in-situ formation of the SiCO network via a sol-gel process. The filled gels obtained in this way show an excellent machinability with conventional surface grinding techniques. Heat treatment up to 1500°C initiated crystallization of mullite, which showed intragranular SiC precipitation. Based on microstructure characterization in conjunction with thermal analysis, a formation mechanism is proposed which includes the glass transition temperature of SiCO as well as its phase separation into SiO2 plus nanosized SiC crystallites, giving rise to this new mullite-SiC nanocomposite.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione
