A WHISKER REINFORCED HIGH TEMPERATURE STRUCTURAL INSULATION

NEW, UNIQUE HIGH TEMPERATURE CERAMIC MATRIX COMPOSITES WITH LOW THERMAL CONDUCTIVITY, HIGH STRENGTH AND THERMOCHEMICAL STABILITY TO 5000 DEGREES FAHRENHEIT (2760 DEGREES CENTIGRADE) ARE A PREREQUISITE TO SIGNIFICANT ADVANCES IN HEAT SHIELD TECHNOLOGY. AVAILABLE HEAT SHIELDS INCLUDE CARBON PHENOLICS WHICH OCCUPY A LOT OF SPACE AND MORE RECENTLY DEVELOPED REUSABLE SURFACE INSULATION UTILIZING RIGID FIBROUS STRUCTURE OF SILICA AND ALUMINA HAVE A LIMITEDTEMPERATURE CAPABILITY TO ABOUT 2500 DEGREES FAHRENHEIT. BOTH OF THESE HEAT SHIELD INSULATORS HAVE EXTREMELY LOW MECHANICAL PROPERTIES. SOME CERAMIC OXIDES HAVE THERMOCHEMICAL STABILITY TO TEMPERATURES IN THE RANGE OF 5000 DEGREES FAHRENHEIT. SUCH COMPOSITIONS COUPLED WITH SELECTED ADVANCED WHISKER REINFORCEMENTS OFFER THE POTENTIALTO PRODUCE CERAMIC COMPOSITES WITH ULTRA HIGH TEMPERATURE STRUCTURAL AND INSULATIVE PROPERTIES THAT HAVE NOT HERETOFORE BEEN ACHIEVED. SOL-GEL TECHNOLOGY COUPLED WITH APLASMA SINTERING TECHNIQUE PRODUCES A POROUS YET WELL BONDEDCOMPOSITE THAT HAS VERY LOW THERMAL CONDUCTIVITY WITH GOOD STRUCTURAL STRENGTH. THIS PROGRAM PROPOSES TO FABRICATE NEWAND UNIQUE ZIRCONIA MATRIX BASED COMPOSITES WITH WHISKER REINFORCEMENTS AND EVALUATE THERMAL AND MECHANICAL PROPERTIES FOR THE DEVELOPMENT OF A LOAD BEARING HEAT SHIELD IN 5000 DEGREES FAHRENHEIT ENVIRONMENT REGIONS.