From custom-engineered polymer precursors to silicon carbonitride-based fibers
| Reference | Presenter | Authors (Institution) | Abstract |
|---|---|---|---|
| 18-045 | David Lopez Ferber | Lopez Ferber, D.(Institut de Recherche sur les Céramiques); Viard, A.(University of Bayreuth); Lucas, R.(Institut de Recherche sur les Céramiques); Motz, G.(Universität Bayreuth); Bernard, S.(Institut de Recherche sur les Céramiques); | Ceramic fibers
are of great interest as reinforcing agents for ceramic matrix composites
(CMCs). Research and development over last decades have mainly focused on using
silicon carbide (SiC)-based fibers as reinforcing agents because of their high
mechanical properties. There are three generations of SiC-based fibers; the properties of the third-generation
fibers approaching those of pure crystalline SiC. This was in particular
related to the addition of boron in the Si-C-O precursor fibers; boron acting
as a sintering aid of SiC during the decomposition of the oxycarbide phase.
These works nicely illustrated the contribution of the organosilicon precursor
chemistry to fiber design. These fibers are still being produced by NGS
Advanced Fibers Co., Ltd, Ube Industries, Ltd and COI ceramics, Inc. Alternative compositions based on the silicon-carbon-nitrogen (Si-C-N) system allows significantly reducing the cost of polymer-derived non-oxide ceramic fibers while comparable mechanical performances could be expected . Such fibers are derived from polysilazanes as precursors. Additionally, the introduction of boron in polysilazanes offers an excellent stability to the derived amorphous Si-C-N network at high temperature. These properties make Si-B-C-N fibers a prime candidate for applications as reinforcing agents. In this presentation, we will discuss our recent results concerning the elaboration and characterization of Si-B-C-N fibers. We will focus our work on the chemistry behind the synthesis of boron-modified polysilazanes. A detailed characterization of melt-spinnable polymers is provided. Then, polymers are melt-spun into green fibers before curing under ammonia then pyrolysis under nitrogen at 1000°C. The high temperature behavior and mechanical properties of fibers are investigated. As a proof of concept, we will present the design of hollow fibers that opens application of these materials as support for membranes. <!--[if gte mso 9]> |
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