Abstract: An article used for thermal protection includes a base structure having at least one surface. The base structure is made of a ceramic oxide material. A silicide coating is formed on the at least one surface of the base structure. The coating comprises a refractory metal and silicon, which together form a silicide. The coating is at least partially diffused into the base structure at the at least one surface.

Abstract: An article used for thermal protection includes a base structure having at least one surface. The base structure is made of a ceramic oxide material. A silicide coating is formed on the at least one surface of the base structure. The coating comprises a refractory metal and silicon, which together form a silicide. The coating is at least partially diffused into the base structure at the at least one surface.

Abstract: An article used for thermal protection includes a base structure having at least one surface. The base structure is made of a ceramic oxide material. A silicide coating is formed on the at least one surface of the base structure. The coating comprises a refractory metal and silicon, which together form a silicide. The coating is at least partially diffused into the base structure at the at least one surface.

Abstract: Low density fused fibrous ceramic composites are prepared from amorphous silica and/or alumina fibers with 2 to 12% boron nitride by weight of fibers, used as a fluxing agent to reduce the melting temperature of the fibers and allow the fibers to fuse at their intersections creating a three dimensional rigid matrix. The matrix is useful as a cell-culture substrate, as an implant material, and for chromatographic separation of blood cells.

Abstract: An acoustic structure for use as a sound insulator in a jet engine is disclosed. The structure, which is carried in a sound-absorbing compartment of the engine, includes a framework and an acoustical insulation material disposed within the framework. The material is composed of a rigid matrix of randomly oriented, fused silica fibers having fiber diameters predominantly in the range 2-8 .mu.m, a three-dimensionally continuous network of open, intercommunicating voids, a flow resistivity between about 10-200K rayls/m, and a density of between about 2 and 8 lb/ft3. Also disclosed are a clad acoustical structure for sound attenuation in a jet engine, where operational temperatures exceed current jet engine designs, and a method of attenuating jet engine noise.