3D Cf/ZrB2-SiC Composites Fabricated by Reactive Hot Pressing: Microstructure and High Temperature Mechanical Properties

Reactive hot pressing technology facilitates the rapid densification and sintering of UHTC-based composites, presenting significant potential for applications in the aerospace field. However, challenges persist in achieving uniform dispersion of fibers and lowering the densification temperature required for optimal consolidation. In this work, the ZrSi 2 , B 4 C and active carbon were used as the raw materials, and the 3D C f /ZrB 2 -SiC composite with an open porosity of 0.91% were successfully fabricated through the slurry impregnation-drying cycles followed by a reactive hot pressing at 1800 °C. The microstructure evolution and high-temperature mechanical properties were also systematically investigated. The microstructure analysis found that the in situ reaction of ZrSi 2 , B 4 C and active carbon during sintering led to the formation of ZrB 2 -SiC ceramic matrix and effectively promoted densification. The 3D C f /ZrB 2 -SiC composite exhibited an average flexural strength of 232.9   MPa at RT, retaining a value of 112.1   MPa at 1200 °C.