Preparation and characterization of NextelTM 720/ alumina ceramic composites via the prepreg process

Abstract In this work, the continuous Nextel™ 720 fiber reinforced alumina ceramic matrix composites (CMCs) were prepared by the prepreg process. The alumina matrix derived from aqueous slurry, which consisted of organic glue, alumina sol, nanometer alumina powder and micrometer alumina powder. This combination endowed the ceramic matrix composite with the prepreg processing capability, making the low-cost fabrication of complex shape components possible. The ratio of different alumina sources in aqueous slurry was optimized to offer good sintering activity, high thermal resistance, and excellent mechanical properties simultaneously. Furthermore, the preceramic polymer of mullite was used to strengthen the ceramic matrix through multiple impregnation process. The final CMC sample achieved a high flexural strength of 255 MPa and a good high-temperature stability. The maximum flexural strength of the CMC sample still remained 85% after heat-treatment at 1100 ℃ for 24 h.