Accession Number : ADA329738

Title :   Beta-Alumina Fiber Matrix Interfacial Coatings

Descriptive Note : Final rept. 1 Jul 94-30 Jun 97

Corporate Author : GEORGIA INST OF TECH ATLANTA

Personal Author(s) : Lackey, W. J. ; Lewis, J. S. ; Richards, R. ; Pickering, E. ; King, H. C.

PDF Url : ADA329738

Report Date : 31 AUG 1997

Pagination or Media Count : 7

Abstract : Three technical areas were pursued during this three year project: oxidation resistant beta-alumina fiber matrix interface coatings, prediction and experimental verification of the microstructure of CVD/CVI carbon, and a new class of laminated matrix composite. Magnetoplumbite and beta-alumina fiber coatings were synthesized by powder feeding of metalorganic reagents into a hot wall reactor. Annealing temperature was found to control both the phase assemblage and the extent of preferred orientation. For the second area, combination of thermodynamic microstructure and densification models permitted prediction of the microstructure of the carbon matrix deposited during forced flow thermal gradient chemical vapor infiltration (FCVI). The model also showed that it should be possible to deposit, by the FCVI process, either isotropic or highly anisotropic carbon. The former might be desirable for structural applications while the later is best when high thermal conductivity is of most interest. Finally, a new class of composite material possessing a laminated matrix was conceived. The new material was experimentally demonstrated with alternate layers of carbon and SiC having layer thicknesses in the range 0.01 to 0.5 micrometers. It is anticipated that the laminated matrix will enhance fracture toughness and may provide improved resistance to oxidation compared to carbo-carbon composites.

Descriptors :   *CHEMICAL VAPOR DEPOSITION, *METAL COATINGS, *CORROSION RESISTANCE, *ANISOTROPY, TEMPERATURE, ANNEALING, MICROSTRUCTURE, THERMODYNAMICS, LAMINATES, MATRIX MATERIALS, CARBON, OXIDATION, THERMAL CONDUCTIVITY, CHEMICAL AGENTS.

Subject Categories : Coatings, Colorants and Finishes

Distribution Statement : APPROVED FOR PUBLIC RELEASE