Preparation and characterization of ceramic composites derived from rice husk ash and polysiloxane

Ceramic matrix composites (CMCs) were prepared from a polysiloxane network filled with rice husk ash (RHA), a reactive filler. CMCs were obtained by pyrolysis at 1000 and 1600 degrees C of green bodies prepared from a mixture of polysiloxane network and RHA at a weight ratio of 4: 1, respectively. The RHA and the CMCs were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS), in addition to density and mechanical measurements. The CMCs were obtained without macroscopic defects, and their initial observed porosity was reduced by polymeric infiltrations cycles of the polymeric precursor, which improved their flexural strength and modulus up to 100%. (c) 2007 Elsevier Ltd and Techna Group S.r.l. All rights reserved.