Microstructures and Thermophysical Properties of Polymer Derived SiC/C Composites

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Polymer derived SiC ceramics usually present a relatively low thermal conductivity for the large porosity and complex phases. In order to obtain condensed SiC ceramic with low thermal conductivity, a preceramic precursor polycarbosilane (PCS) was selected as the raw materials. And hot press sintering processes were performed at 1600 °C under Ar atmosphere with the holding time in the range of 20 to 40 min for consolidation. The microstructures and phases were analyzed by scanning electron microscopy (SEM) with energy disperse X-ray spectroscopy (EDS), X-ray diffraction (XRD) and high-resolution transmission electron microscope (HRTEM). The specific heat, thermal diffusivities and thermal conductivities were measured and investigated from room temperature to 650 °C. A minimum thermal conductivity of 4.13 W•m-1•K-1 was obtained at 650 °C with a holding time of 30 min.

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86-90

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January 2012

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© 2012 Trans Tech Publications Ltd. All Rights Reserved

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