Abstract: An apparatus and method for consolidating a composite workpiece are provided. The apparatus includes an electromagnetic field generator for inducing a current and thereby heating a susceptor in thermal communication with the workpiece. The workpiece is supported by one or more support tools, each of which transmits the electromagnetic field so that the support tools are not substantially heated by the electromagnetic field. Thus, the time and energy required for heating the workpiece are reduced relative to conventional consolidation techniques.

Abstract: An apparatus and method for consolidating a composite workpiece are provided. The apparatus includes an electromagnetic field generator for inducing a current and thereby heating a susceptor in thermal communication with the workpiece. The workpiece is supported by one or more support tools, each of which transmits the electromagnetic field so that the support tools are not substantially heated by the electromagnetic field. Thus, the time and energy required for heating the workpiece are reduced relative to conventional consolidation techniques.

Abstract: An apparatus and method for consolidating a composite workpiece are provided. The apparatus includes an electromagnetic field generator for inducing a current and thereby heating a susceptor in thermal communication with the workpiece. The workpiece is supported by one or more support tools, each of which transmits the electromagnetic field so that the support tools are not substantially heated by the electromagnetic field. Thus, the time and energy required for heating the workpiece are reduced relative to conventional consolidation techniques.

Abstract: An apparatus and method for consolidating a composite workpiece are provided. The apparatus includes an electromagnetic field generator for inducing a current and thereby heating a susceptor in thermal communication with the workpiece. The workpiece is supported by one or more support tools, each of which transmits the electromagnetic field so that the support tools are not substantially heated by the electromagnetic field. Thus, the time and energy required for heating the workpiece are reduced relative to conventional consolidation techniques.

Abstract: A fibrous ceramic mat is molded from a slurry of ceramic fibers and/or ceramic micropartides and/or a metal. The mat is impregnated with a sol prior to drying. A catalyst for the sol is introduced into the mat to cause the sol to gel. The sol-gel binder forms bonds so that the mat is dimensionally stabilized. The mat is dried to produce the desired ceramic insulation that has preferably a consistent microstructure and a fully gelled sol-gel binder through its entire thickness. If we use a metal, it corrodes (i.e., oxidizes) or otherwise reacts to form a refractory binder that augments the sol and reduces the need to infuse sol incrementally to achieve strength. Using metal powder significantly reduces the cost of manufacture.

Abstract: A fibrous ceramic mat is molded from a slurry of ceramic fibers and/or ceramic microparticles and/or a metal. The mat is impregnated with a sol prior to drying. A catalyst for the sol is introduced into the mat to cause the sol to gel. The sol-gel binder forms bonds so that the mat is dimensionally stabilized. The mat is dried to produce the desired ceramic insulation that has preferably a consistent microstructure and a fully gelled sol-gel binder through its entire thickness. If we use a metal, it corrodes (i.e., oxidizes) or otherwise reacts to form a refractory binder that augments the sol and reduces the need to infuse sol incrementally to achieve strength. Using metal powder significantly reduces the cost of manufacture.

Abstract: A coated ceramic has alumina as an amorphous residue from an alumina sol containing alumina powder or and, optionally, a high emittance powder. The alumina powder alters the rheology and wetting characteristics of the sol to aid in forming the residue and increases the alumina concentration (% solids) in the residue. The high emittance powder radiates heat out of the residue and away from the ceramic when the coated ceramic is heated, such as during orbital reentry.

Abstract: A slurry is molded from ceramic fibers and/or microparticles to form a soft felt mat which is impregnated with a sol prior to drying the mat. A catalyst for the sol is caused to diffuse into the mat by exposing the mat to the catalyst and subjecting the mat to a soak time during which the catalyst diffuses into the mat and causes the sol to gel. The sol-gel binder forms bonds so that the mat is dimensionally stabilized. The mat is dried to produce ceramic insulation.Ceramic insulation having a consistent microstructure and a fully gelled sol-gel binder through its entire thickness is also provided.

Abstract: A fibrous ceramic mat is molded from a slurry of ceramic fibers and/or ceramic microparticles and/or a metal. The mat is impregnated with a sol prior to drying. A catalyst for the sol is introduced into the mat to cause the sol to gel. The sol-gel binder forms bonds so that the mat is dimensionally stabilized. The mat is dried to produce the desired ceramic insulation that has preferably a consistent microstructure and a fully gelled sol-gel binder through its entire thickness. When a metal is used, it corrodes (i.e., oxidizes) or otherwise reacts to form a refractory binder that augments the sol and reduces the need to infuse sol incrementally to achieve strength. Using metal powder significantly reduces the cost of manufacture.

Abstract: A slurry is molded from ceramic fibers and/or microparticles to form a soft felt mat which is impregnated with a sol prior to drying the mat. A catalyst for the sol is caused to diffuse into the mat by exposing the mat to the catalyst and subjecting the mat to a soak time during which the catalyst diffuses into the mat and causes the sol to gel. The sol-gel binder forms bonds so that the mat is dimensionally stabilized. The mat is dried to produce ceramic insulation.

Abstract: A slurry is molded from ceramic fibers and/or microparticles to form a soft felt mat which is impregnated with a sol prior to drying the mat. A catalyst for the sol is caused to diffuse into the mat by exposing the mat to the catalyst and subjecting the mat to a soak time during which the catalyst diffuses into the mat and causes the sol to gel. The sol-gel binder forms bonds so that the mat is dimensionally stabilized. The mat is dried to produce ceramic insulation, ceramic insulation having a consistent microstructure and a fully gelled sol-gel binder through its entire thickness.

Abstract: A monolithic silicon nitride radome structure having a forward portion, an after portion and a transition portion therebetween, is provided. The forward portion has a density of about 0.75 to 1.0 g/cc, the after portion has a density of about 1.6 to 2.0 g/cc and the transition portion has regions of increasing density, from forward to aft, each region having a greater density than the preceding portion or region. Also provided is a method for manufacturing the above-described radome structure which comprises filling and compacting a series of formulations consisting essentially of particulate silicon, silicon nitride and a fugitive pore-forming material into a radome mold, removing the shaped compact from the mold, subliming the pore-forming material from the compact to form a porous compact structure, and reacting the porous structure with nitrogen to convert the porous structure to an identically shaped radome structure of .alpha.-silicon nitride whiskers.

Abstract: Oxide-based ceramic fibers are treated in a novel process to create a substantially uniform boron nitride barrier coating at their surface. The process involves heating the fibers in a nitriding atmosphere at between about 2200-2600.degree. F. to create a BN coating at the surface of the fiber from boron initially within the fiber.

Abstract: Oxide-based ceramic fibers are treated in a novel process to create a substantially uniform boron nitride barrier coating at their surface. The process includes the step of heating the fiber, preferably an aluminoborosilicate fiber like NEXTEL, for between about 5-90 minutes in a nitriding atmosphere of ammonia, hydrogen and nitrogen at a temperature of between about 2200.degree.-2600.degree. F. to diffuse boron from the fiber to the surface of the fiber where it reacts to form the boron nitride coating.

Abstract: A method for producing .alpha.-silicon nitride whiskers. Silicon is blended with amorphous silicon nitride and a pore-forming composition particles able to be removed without leaving a residue, such as naphthalene particles. The mixture is compacted to a desired shape, after which the pore-forming particles are removed from the mixture to form a porous silicon precursor compact having the desired shape. The silicon precursor is reacted with a substance that releases free nitrogen, such as nitrogen or dry ammonia. The reaction is carried out at a temperature sufficiently high to form an identically shaped porous compact of .alpha.-silicon nitride whiskers but sufficiently low to avoid subliming substantially all of the formed whiskers. Preferably, the reaction is carried out in a range between about 1100.degree. C. and 1500.degree. C. The shaped porous compact of .alpha.

Abstract: A sound attenuating laminate exhibiting a relatively low change in acoustic resistance with respect to particle velocity is disclosed. The laminate includes a gas permeable mat of randomly arranged, small diameter filaments interleaved between two layers of resin impregnated, open weave web or cloth. A predetermined pattern of adhesive applied to the filamentous mat penetrates the mat to bond the laminate into an integral structure. The laminate can be easily fabricated to form sound attenuating panels having a variety of contours by curing the composite within a mold.