Cf/(CrZrHfNbTa)C–SiC high-entropy ceramic matrix composites for potential multi-functional applications

In this work, Cf/(CrZrHfNbTa)C-SiC high-entropy ceramic matrix composites with good load-bearing, electromagnetic shielding and ablation resistance were designed and reported for the first time. The composites were fabricated by an efficient combined processing of slurry infiltration lamination (SIL) and precursor infiltration and pyrolysis (PIP). Density and porosity of the as-fabricated composites are 2.72 g/m3 and 12.44 vol.%, respectively, and the flexural strength is 185 ± 13 MPa. Due to the carbon fiber reinforcement with high conductivity and strong reflection, and high-entropy (CrZrHfNbTa)C ceramic matrix with strong absorbability, the total Electromagnetic interference shielding efficiency (SET) of the composites with a thickness of 3 mm are as high as 88.2 dB and 90 dB respectively in X-band and Ku-band. This means that higher than 99.999999% electromagnetic shielding is achieved at 8-18 GHz, showing excellent electromagnetic shielding performance. The Cf/(CrZrHfNbTa)C-SiC composites also present excellent ablation resistance, with the linear and mass ablation rates of 0.9 μm/s and 1.82 mg/s after ablation at the heat flux of 5 MW/m2 for 300 s (∼2450°C). This work opens a new insight for the synergistic design of structural and functional integrated materials with load-bearing, electromagnetic shielding and ablation resistance, etc.