Chapter 38. Special Modified Silazanes for Coatings, Fibers and CMC'S
- Todd Jessen,
- Ersan Ustundag
Published Online: 28 MAR 2008
Copyright © 2000 The American Ceramic Society
24th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: B: Ceramic Engineering and Science Proceedings, Volume 21, Issue 4
How to Cite
Motz, G., Hacker, J. and Ziegler, G. (2008) Special Modified Silazanes for Coatings, Fibers and CMC'S, in 24th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: B: Ceramic Engineering and Science Proceedings, Volume 21, Issue 4 (eds T. Jessen and E. Ustundag), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470294635.ch38
- Published Online: 28 MAR 2008
- Published Print: 1 JAN 2000
Print ISBN: 9780470375693
Online ISBN: 9780470294635
- tailored precursors;
- liquid phase infiltration;
- organometallic compound;
- preceramic polymers
Tailored precursors in the systems Si-C-N(Ti) were synthesized for various appli- cations by different reaction types by using the same two chlorosilanes. For the liquid phase infiltration (LP1)-process coammonolysis of CH3Cl2SiH and CH3Cl2SiCH=CH2 leads to a liquid cross-linkable precursor with a high ceramic yield (75 %) after pyrolysis at 1400°C. Therefore, this precursor is excellent as matrix source for CMCs.
Hydrosilylation of the chlorosilanes as the first step and subsequent ammonolysis result in a meltable solid (∼ 100°C). This precursor was produced in a pilot plant and continuously meltspun to fibers with small diameters (∼ 20 μm). Curing of the polymer fibers and subsequent pyrolysing at 1000°C (N2) lead to non-oxide SiCN fibers.
The liquid SiCN precursor modified by organometallic compounds (e.g. Ti(NR2)4) results in unmeltable but soluble solids. These polymers are suitable for applications as inorganic polymer-, and at higher temperatures, as ceramic-like-coatings (CLC). With corresponding precursor solutions different substrates (metals, ceramics, glass, plastics) with complex-shaped geometry can be coated by using simple dip- and spray-coating techniques. In all cases the adhesion to the substrate is very strong.
Selected results from the research areas mentioned above are presented in order to illustrate the potential of these silazane-based materials, with particular emphasis on the latest results of coating investigations.