Effect of Pyrolysis Temperature on the Piezoresistivity of Polymer-Derived Ceramics

Authors

  • Yiguang Wang,

    1. National Key Laboratory of Thermostructure Composite Materials, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China
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    • *Member, The American Ceramic Society.

  • Jian Ding,

    1. National Key Laboratory of Thermostructure Composite Materials, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China
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  • Wei Feng,

    1. National Key Laboratory of Thermostructure Composite Materials, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China
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  • Linan An

    Corresponding author
    1. National Key Laboratory of Thermostructure Composite Materials, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China
    2. Advanced Materials Processing and Analysis Center, University of Central Florida, Orlando, Florida 32826
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  • R. Riedel—contributing editor

  • This work was supported by the “111” program (B08040) and the National Science Foundation of USA (DMR-0706526).

†Author to whom correspondence should be addressed. e-mail: lan@mial.ucf.edu

Abstract

Amorphous silicon carbonitride (SiCN) ceramics were synthesized by pyrolyzing a polysilazane at different temperatures between 900° and 1400°C. The microstructures and compositions of the materials obtained were analyzed using X-ray diffraction, elemental analysis, and Raman spectroscopy. To study their piezoresistive behavior, the resistivity of the resultant materials were measured as a function of applied stress. We found that the piezoresistive behavior of all materials can fit the tunneling-percolation model. The piezoresistive stress coefficient of the materials obtained at temperatures below 1200°C showed both reverse and logarithmical dependences on applied stress, but that of the materials obtained at higher temperatures showed only logarithmical dependence. We believe that the pyrolysis temperature induces a change in the free carbon structure thus, causing this effect on the piezoresistivity.

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