Mechanical properties and oxidation behaviors of carbon/carbon composites with C–TaC–C multi-interlayer

To improve the mechanical properties and oxidation-resistance properties, a C–TaC–C multi-interlayer structure was introduced in carbon/carbon (C/C) composites by chemical vapor infiltration. Compared with conventional C/C composites, a higher fracture toughness and strength have been achieved by using the C–TaC–C multi-interlayer. In addition, the composites also exhibit a higher preliminary oxidation temperature and a lower mass loss at high temperatures. The oxidation rate of the composites increases with temperature increasing in the range of 700–1300 °C, reaching a maximum value at 1300 °C, then decreases in 1300–1400 °C. A hexagonal structure of Ta2O5 phase is obtained when being oxidized at 700–800 °C, and it transforms to an orthorhombic phase at temperatures above 900 °C. The structures of C–TaC–C multi-interlayer are intact without cracks or porosities after being oxidized at 700–800 °C. In 900–1300 °C, the composites are oxidized uniformly with the formation of pores. At temperatures above 1300 °C, there are oxidation and non-oxidation regions with the oxidation process being controlled by diffusion.