Abstract: Aluminum oxide ceramic composite articles having high flexural and tensile strength are produced by introducing a liquid aluminum oxide precursor material into a ceramic reinforcement fabric, curing the precursor material at an elevated temperature, and converting the cured precursor material to an aluminum oxide ceramic by pyrolysis at temperatures which do not result in the degradation of the reinforcement material. Such ceramic composite articles are particularly useful for applications requiring a low dielectric constant and a high mechanical strength.

Abstract: Reinforced composite tubes are formed by rolling a flat reinforcement fabric onto a cylindrical or conical mandrel under tension. By pre-impregnating the fabric with a suitable matrix precursor or by serving the individual threads of the fabric with a thermoplastic, the fabric may be compressed by applying heat and pressure during the rolling process. After rolling, the resulting prepreg is cured in a suitable vacuum bag, also under heat and pressure. The cured prepreg may then be converted by pyrolysis and densified by repeated impregnation and converting steps. The resulting composite tubes are substantially free from mechanical defects which would reduce their strength.

Abstract: Ceramic composite articles having high flexural and tensile strength are produced by introducing multiple layers of a ceramic matrix material onto a ceramic reinforcement fabric. Crack propagation in the resulting structure is inhibited by applying refractory interface layers intermediate successive ceramic matrix layers. Such ceramic composite articles are particularly useful for high temperature applications requiring a high degree of strength, such as rocket motor insulation and turbine blades, combustion chambers, and after burners for jet motors.

Abstract: Rigidized composite preforms are fabricated by first serving individual reinforcement strands with a thread of a thermoplastic material. After shaping the reinforcement strands into a desired geometry, the shaped strands are heated to melt the thermoplastic threads. By then cooling the shaped reinforcement strands, the thermoplastic material solidifies and acts as an adhesive or glue in holding the preform together in a rigid fashion. Such rigid preforms are particularly suitable for handling, storage and transportation to other locations and media prior to densification. Densification may be performed by conventional techniques to produce the final composite article. Pyrolysis of the matrices and subsequent densification of the matrix may be accomplished.