Processing and Properties of Nextel™ 720 Fiber Reinforced Alumina-Zirconia Ceramic Matrix Composites

The continuous NextelTM 720 fiber-reinforced zirconia/alumina ceramic matrix composites (CMCs) were pre-pared by slurry infiltration process and precursor infiltration pyrolysis (PIP) process. The introduction of sub -micron zirconia powders into the aqueous slurry was optimized to offer comprehensively good sintering activity, high thermal resistance and good mechanical properties for the CMCs. Meanwhile, the zirconia and alumina preceramic polymers were used to strengthen the porous ceramic matrix through the PIP process. The final CMC sample achieved a high flexural strength of 200 MPa after one infiltration cycle of alumina preceramic polymer and thermal treatment at 1150 degrees C for 2 h. The flexural strength retention of the improved CMC sample was 104% and 89% respectively after thermal exposure at 1100 degrees C and 1200 degrees C for 24 h.