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POLYMER-DERIVED CERAMICS: ELECTRONIC PROPERTIES AND APPLICATION

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Date Issued:
2006
Abstract/Description:
In this work, we studied the electronic behavior of polymer-derived ceramics (PDCs) and applied them for the synthesis of carbon nanotube reinforced ceramic nanocomposites and ceramic MEMS (Micro-Electro-Mechanical Systems) structures. Polymer-derived SiCN ceramics were synthesized by pyrolysis of a liquid polyureasilazane with dicumyl peroxide as thermal initiator. The structural evolution during pyrolysis and post-annealing was studied using FTIR, solid state NMR and Raman. The results revealed that the resultant ceramics consisted of SiCxNx-4 as major building units. These units were connected with each other through C-C/C=C bonds or by shearing N/C. The amount of sp2 free carbon strongly depends on composition and processing condition. Electron paramagnetic resonance (EPR) was used to investigate electronic structure of PDCs; the results revealed that the materials contain unpaired electron centers associated with carbons. Electronic behavior of the SiCN ceramics was studied by measuring their I-V curves, temperature dependence of d.c.-conductivities and impendence. The results revealed that the SiCN ceramics exhibited typical amorphous semiconductor behavior, and their conductivity varied in a large range. The results also revealed that the materials contain more than one phase, which have the different electronic behavior. We explored possibility of using polymer-derived ceramics to make ceramic MEMS for harsh environmental applications with a lithography technique. The cure depth of the polymer precursor was measured as a function of UV intensity and exposure time. The experimental data was compared with the available theoretical model. A few typical SiCN parts were fabricated by lithography technique. We also prepared carbon nanotube reinforced ceramic nanocomposites by using PDC processing. The microstructures of the composites were characterized using SEM and TEM; the mechanical properties were studied characterized using nanoindentation. The significant improvement in mechanical properties was observed for the nanocomposites.
Title: POLYMER-DERIVED CERAMICS: ELECTRONIC PROPERTIES AND APPLICATION.
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Name(s): xu, weixing , Author
An, Linan, Committee Chair
University of Central Florida, Degree Grantor
Type of Resource: text
Date Issued: 2006
Publisher: University of Central Florida
Language(s): English
Abstract/Description: In this work, we studied the electronic behavior of polymer-derived ceramics (PDCs) and applied them for the synthesis of carbon nanotube reinforced ceramic nanocomposites and ceramic MEMS (Micro-Electro-Mechanical Systems) structures. Polymer-derived SiCN ceramics were synthesized by pyrolysis of a liquid polyureasilazane with dicumyl peroxide as thermal initiator. The structural evolution during pyrolysis and post-annealing was studied using FTIR, solid state NMR and Raman. The results revealed that the resultant ceramics consisted of SiCxNx-4 as major building units. These units were connected with each other through C-C/C=C bonds or by shearing N/C. The amount of sp2 free carbon strongly depends on composition and processing condition. Electron paramagnetic resonance (EPR) was used to investigate electronic structure of PDCs; the results revealed that the materials contain unpaired electron centers associated with carbons. Electronic behavior of the SiCN ceramics was studied by measuring their I-V curves, temperature dependence of d.c.-conductivities and impendence. The results revealed that the SiCN ceramics exhibited typical amorphous semiconductor behavior, and their conductivity varied in a large range. The results also revealed that the materials contain more than one phase, which have the different electronic behavior. We explored possibility of using polymer-derived ceramics to make ceramic MEMS for harsh environmental applications with a lithography technique. The cure depth of the polymer precursor was measured as a function of UV intensity and exposure time. The experimental data was compared with the available theoretical model. A few typical SiCN parts were fabricated by lithography technique. We also prepared carbon nanotube reinforced ceramic nanocomposites by using PDC processing. The microstructures of the composites were characterized using SEM and TEM; the mechanical properties were studied characterized using nanoindentation. The significant improvement in mechanical properties was observed for the nanocomposites.
Identifier: CFE0001228 (IID), ucf:46885 (fedora)
Note(s): 2006-08-01
Ph.D.
Engineering and Computer Science, Department of Mechanical, Materials, and Aerospace Engineering
Doctorate
This record was generated from author submitted information.
Subject(s): polymer
ceramic
electronic behavior
nanotube
nanocomposites
Micro-Electro-Mechanical Systems(MEMS)
Persistent Link to This Record: http://purl.flvc.org/ucf/fd/CFE0001228
Restrictions on Access: public
Host Institution: UCF

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