Mechanical enhancement of lightweight ZrB₂-modified carbon-bonded carbon fiber composites with self-grown carbon nanotubes

Carbon-bonded carbon fiber (CBCF) composites consist of chopped carbon fibers network by vitreous carbon at the intersections with high porosity, low thermal conductivity and higherature resistance. To further enhance mechanical properties of CBCF composites, nanostructured modification can inspire the creation of CBCF composites with tunable mechanical properties. Here, we report an self-grown strategy to prepare carbon nanotubes (CNTs) and ZrB₂-modified CBCF composites with a green and single-step process without any foreign gases. The CNTs-ZrB₂ was directly self-grown in CBCF matrix from zirconium (Zr) and boron (B)-contained polymeric precursors during thermal pyrolysis. Results showed that the CNTs are uniformly dispersed in the composites with several hundred micrometers length. The CNTs play a significant role on improving mechanical properties of CBCF composites by pulling-out and bridging effect compared with CBCF composites without CNTs.