Future atmospheric entry vehicles will need new, reusable, lightweight thermal protection systems capable of withstanding significantly higher heat fluxes than is possible with currently available materials. A low density foam of a zirconia-silica-boria composition will be synthesized by a sol-gel route, using a known method for making hollow ceramic microspheres and cast bricks of refractory insulation material. Surface layers of such glassy oxides are formed in-situ during plasma arc-jet testing of zirconium diboride-silicon carbon-carbon advanced refractory composites. The refractory foam is expected to have exceptionally good resistance to thermal shock and to exhibit a low recession rate at temperatures of 2400øC.
Potential Commercial Applications:The porous refractory material has commercial applications as a high-temperature furnace insulation and as an insulating material for heat engines and rockets.
