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U.S. Department of Energy
Office of Scientific and Technical Information

Ceramic-fiber coating development and demonstration. Annual technical report, 1 Jul 89-31 Dec 90

Technical Report ·
OSTI ID:5392172
The objective of this program is to develop fiber coating techniques by gas phase and liquid phase processes. Thermochemical evaluation of fiber/coating/matrix systems was completed. Experimental studies on chemical and mechanical interaction between coating and substrate materials indicate no reaction zones in samples treated up to 1400 C. Mechanical tests revealed that the strength of interfaces decreases with increasing temperature treatment. Nicalon, Nextel and FR-PRD-166 fibers were coated with SiC and Si3N4 from preceramic polymer solutions. The same fibers were coated with Y2O3, Al2O3, MgAl2O4. YAlO3 and MgO from aqueous nitrate sols. Tensile strengths for Y2O3 coated Nicalon are comparable to as received fibers while Al2O3 coated Nicalon exhibits a 20% degradation. Nicalon, HPZ, Nextel and FP-PRD-166 were CVD coated with SiC. TEM data for Al2O3 coatings show evidence of crystallinity above 800 C annealing temperature.
Research Organization:
General Atomics, San Diego, CA (United States)
OSTI ID:
5392172
Report Number(s):
AD-A-234773/0/XAB; GA-C--20422; CNN: F49620-89-C-0078; ARPA Order-6808
Country of Publication:
United States
Language:
English