Ceramic Fibers and Coatings Advanced Materials for the Twenty-First Century (1998) / Chapter Skim
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8 Recommendations and Future Directions
8 Recommendations and Future Directions
Pages 83-86
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From page 83... ...
Producing the database will require the following steps: 83 · existing nonclassified data that is not broadly accessible because of its association with classified or restricted studies be made generally available (in particular, the committee recommends that, wherever possible, agency owned engineering data be made accessible and that new programs avoid restricting data) · data that is currently classified be reassessed to determine if it can be declassified and, if so, that it be made more generally available · low risk, government sponsored insertion programs for CMCs be expanded to demonstrate the field performance of CMC components · standardized tests for obtaining engineering data on CMCs be instituted or developed.
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From page 84... ...
Coating approaches that promise to provide damage tolerant oxide composites should be evaluated to prove or disprove their viability. Based on the preliminary results discussed in Chapter 6, the committee has concluded that research should be focused on the following areas: weakly bonded, thermally stable oxide coatings (e.g., rare-earth phosphates of the general formula Me3+PO4~; and the development of oxide composites that do not require fiber coatings (e.g., porous matrices)
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From page 85... ...
The key areas of investigation recommended for non-oxide fibers are recently developed amorphous non-oxide fibers, such as Si-B-N-C fibers, to verify their stability and creep resistance and the utility of the reported in-situ coatings, and microstructural refinements to improve performance in crystalline non-oxide fibers. The development of higher temperature, higher performance fibers will enable the use of CMCs in long service-life, high-temperature applications (e.g., thermally loaded gas turbine engine components and heat exchangers for externally fired combined cycle power systems)
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From page 86... ...
The development and use of less expensive fiber precursors also offer a potential reduction in variable costs. Finally, because applying coatings to fibers via CVD adds considerably to the final cost of CMCs, liquid precursor coatings or coatings developed on the fiber in-situ (without a separate processing step)
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