Oxycarbide Glasses in the Mg-Al-Si-O-C System |
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Authors: | JOSEPH HOMENY GREGORY G NELSON SUBHASH H RISBUD |
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Affiliation: | Department of Ceramic Engineering, University of Illinois, Urbana, Illinois 61801;Department of Materials Science and Engineering, University of Arizona, Tucson, Arizona 85721 |
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Abstract: | Oxycarbide glasses in the Mg-Al-Si-O-C system were produced at initial carbon levels of 0.0, 0.5, 1.0, 1.5, 2.0, and 2.5 wt%. Carbon was incorporated into the glass melts by means of SiC additions. The glasses were melted between 1750° and 1800°C under nitrogen atmospheres. The limit of carbon incorporation was reached at the 2.5% carbon level, as these glasses crystallized (predominantly cordierite, 2MgO˙2Al2O3˙5SiO2) upon gradual cooling from the meit. Glasses containing less than 2.5% carbon were amorphous according to standard X-ray diffraction methods. Further examination of these oxycarbide glasses by transmission electron microscopy indicated the lack of microcrystalline phases and the potential for producing clear inclusion-free glasses. The Mg-Al-Si-O-C glasses showed significant increases in density, Young's elastic modulus, shear modulus, Vickers hardness, and fracture toughness with increasing carbon content. |
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