A Novel Process of CNTs/Al2O3 Hybrid Ceramics

Carbon nanotubes possess extraordinary mechanical, thermal and electrical properties. Attempts have been made to develop advanced engineering materials with improved or novel properties through the incorporation of carbon nanotubes in selected matrices (polymers, metals and ceramics). Recently, the use of carbon nanotubes to reinforce ceramic composites has made exciting progress. However, oxidation of CNTs associated with high temperature process is still an challenge. The major disadvantages of current in situ CNT-Fe-Al2O3 nanocomposite ceramic process are 1) carbon nanotubes were damaged due to hot-press high temperature process (>1500°C); 2) Even at 1500°C, the CNT-Fe-Al2O3 nanocomposite ceramic was not sintered. The density is low (< 93% TD); and 3) Poor CNT/ceramic matrix bonding. In this proposed research, the surface of CNTs-Fe-Al2O3 nanocomposite powder will be modified with an ultrathin adhesive layer. With this ultrathin layer, the green density and the bonding between CNTs and Al2O3 powder can be greatly improved. Due to high green density and high electric conductive nature of CNT-Fe-Al2O3 nanocomposite, it is possible to use electrical field assisted rapid sintering process to densify and sinter the CNT-Fe-Al2O3 nanocomposite ceramics at the temperature <1200°C and ambient pressure condition.