| Abstract
| - The preparation of β-SiC/MC (M = Ti, Nb, and Ta) nanocomposite ceramics by the pyrolysisunder an inert atmosphere of precursors consisting in interpenetrating networks of poly[(dimethylsilylene)diacetylene], 1, and polymeric metal oxide is described. The precursorsare obtained by in-situ precipitation of the desired metal alkoxide into the organosiliconpolymeric matrix. The precursor-to-ceramic conversion involved two critical transformations: (i) the thermal cross-linking of 1 and (ii) the carbothermal reduction of the oxide bythe free carbon resulting from the degradation of 1. At 1400 °C, the pure carbides are obtainedas nanometer-sized highly crystalline powders. Analyses have shown that both β-SiC andthe other metal carbide are present simultaneously in each ceramic particle as discretephases. All of these results show that we are faced with materials that can be described asnanocomposite ceramics with interpenetrating networks.
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