Effects of synthesis temperature and Fe catalyst amount on the performance of in situ CNTs/TiB2 composites

Carbon nanotubes (CNTs) were synthesized in situ over TiB2 powders by using a Fe catalyst at temperatures ranging from 800 °C to 1000 °C. The CNT(Fe)-TiB2 composites were then successfully consolidated by spark plasma sintering. Results indicated that CNT(Fe)-TiB2 composites with 20 wt% Fe sintered at 1400 °C for 5 min provided the optimal combination of dense microstructures and excellent properties. These properties included the following: relative density, 97.3%; flexural strength, 985 ± 48 MPa; and fracture toughness, 11.8 ± 0.4 MPa m1/2. Retention of the perfect structure and homogenous dispersion at the molecular level of CNTs in TiB2 matrix were identified as the main factors that contribute to the marked improvement of the mechanical properties of the composites.