Mechanical Properties of Silicon Oxycarbide Ceramic Foams |
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Authors: | Paolo Colombo John R Hellmann David L Shelleman |
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Affiliation: | Dipartimento di Chimica Applicata e Scienza dei Materiali, Universitàdi Bologna, Viale Risorgimento 2, 40136 Bologna, Italy;Materials Research Institute, Department of Material Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 |
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Abstract: | The mechanical properties of ceramic foams obtained through a novel process that uses the direct foaming and pyrolysis of preceramic polymer/polyurethane solutions were investigated. The elastic modulus, flexural strength, and compressive strengths were obtained for foams in the as-pyrolyzed condition; values up to 7.1 GPa, 13 MPa, and 11 MPa, respectively, were obtained. The strength of the foam was virtually unchanged at temperatures up to 1200°C in air; however, long-term exposure at 1200°C led to a moderate degradation in strength, which was attributed to the evolution of intrastrut porosity during the oxidation of residual free carbon, as well as devitrification of the foams struts. |
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Keywords: | silicon oxycarbide foams pores/porosity |
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