High Toughness Ceramics Containing Carbon Nanotube Reinforcement

In January 2003, the US Army Natick Soldier Center awarded a Phase I SBIR contract to NanoLab, Inc. The main contract goal was to improve the toughness of boron carbide armor materials, through the addition of carbon nanotubes. To reach this goal, NanoLabconducted studies to determine suitable blending and compounding techniques to obtain uniformly dispersed composite powders of nanotubes and boron carbide. After identifying suitable blending techniques, NanoLab was given access to the facilities at theArmy Research Laboratory (ARL). The facilities at Aberdeen include a plasma pressure compaction unit. This unit, similar to a hot press, allows the rapid consolidation of ceramic powders into a sintered article, such as an armor tile. With the assistanceof the staff at ARL, NanoLab investigated the processing parameters required to make fully dense boron carbide nanotube composites. Once these parameters were identified, NanoLab used characterization facilities at Boston College and Worcester PolytechnicInstitute to analyze these samples. The analysis revealed that the toughness has been doubled, in comparison to the standard boron carbide. In addition, the high hardness of boron carbide is preserved. These results are based on indent tests, and samplepreparation for ballistic tests are ongoing. The work undertaken in this program will yield tougher, more damage-resistant ceramic components for applications including armor and industrial products. The significant enhancement of the boron carbidetoughness has immediate applications in blast nozzles and other high wear components that suffer from high brittleness.