Effect of preparation conditions on mechanical, dielectric and wave-transparent properties of Al₂O_3f/mullite composites

Alumina fiber reinforced mullite matrix (Al₂O_3f/mullite) composites were prepared by precursor infiltration and sintering (PIS) process. The effects of different sintering temperatures and fiber fabrics volume fractions on the microstructure, mechanical, dielectric and wave-transparent properties of the composites were investigated. The flexural strength decreased sharply and then increased slightly with the increase in sintering temperature. The best flexural strength was obtained 91 MPa at 600 °C for 2 h. Then, the effect of fiber fabrics volume fraction on Al₂O_3f/mullite composite was further investigated at 1000 °C. The experimental results showed that the maximum flexural strength was obtained with 35% of fiber volume fraction. The excellent wave-transparent property was obtained at 600 °C for 2 h and the corresponding high wave-transparent (| T| ²≥ 90 %) bandwidth is 1.60 mm, which implies that Al₂O_3f/mullite composite is a good candidate as wave-transparent materials. This result will provide a basis for further research on fiber-reinforced ceramic matrix composites in the field of wave-transparent.