Polymer-derived porous ceramics from novel silicon-based preceramic/sucrose systems |
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Affiliation: | Ceramics Division, Research Institute for Materials Science and Technology (INTEMA), CONICET-UNMdP, B7606BWV, Mar del Plata, Argentina |
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Abstract: | Porous Si/C/O/(N) ceramic bodies were developed by the direct consolidation of novel liquid silicon-based preceramic polymer/porogen (methacryloxypropyl silsesquioxane/sucrose) systems, burnout, and N2 pyrolysis (1300–1500 °C), and they were characterized via open porosity, volumetric shrinkage, and mass loss measurements. The evolution of phases as temperature increased was analyzed using XRD, TGA-mass spectrometry tests, and 29Si NMR. The free carbon phase was characterized via Raman spectroscopy, and its content was determined using a carbon analyzer. Porous microstructures were analyzed by SEM/EDS and Hg-porosimetry, and by measuring the N2 adsorption/desorption and specific surface area. The final ceramics exhibited a hierarchical porosity composed of large irregular pores that grew with temperature, together with a lower volume of meso- and micropores. β-SiC whiskers and faceted hexagonal crystals of α-Si3N4 were observed inside of cavities. The presence of meso- and micropores explained the high specific surface area achieved in the material pyrolyzed at 1500 °C. |
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Keywords: | Polymer-derived ceramics Silicon-based preceramic polymer Processing Porosity |
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