Preparation and performance of C/Ta4HfC5-SiC composite fabricated by PIP combined with RMI process

Based on self-made Ta4HfC5 precursor, C/Ta4HfC5-SiC composite material were prepared by precursor impregnation and pyrolysis (PIP) combined with reactive melting infiltration (RMI) process. The density and open porosity of C/Ta4HfC5-SiC composite material are 2.71 f 0.73 g/cm3 and 7.07 f 1.29 %, respectively. Pores are distributed at multiple levels, including primarily nanopores below 40 nm, micropores between 0.04 and 8.5 mu m, and a small number of macropores between 10 and 285 mu m. The Ta4HfC5 phase exists in two forms: dispersed particles in the matrix and a "layered interface" on the surface of fibers within the bundle. The average bending strength, elastic modulus and fracture toughness of C/Ta4HfC5-SiC composite are 84.24 f 8.71 MPa, 16.13 f 5.42 GPa and 3.62 f 0.63 MPa m 1/2 , respectively, showing a clear brittle fracture mode during the test. The line ablation rate and mass ablation rate of 60 s assessed by the oxyacetylene flame were 7.20 f 0.35 mu m/s and 10.84 f 0.84 mg/s, respectively. The oxidation products such as Ta2O5, HfO2, Ta(Hf)CxOy formed by Ta4HfC5 phase during ablation present as thicker oxide layers, forming the main anti-ablation components.