Mechanical properties of SiC composites incorporating SiC-coated multi-walled carbon nanotubes

摘要

Multi-walled carbon nanotubes (MWCNTs) were coated with a nanometer-sized SiC polycrystalline layer by the reaction of SiO(g) and CO(g). Nanometer-sized SiC powders were mixed with 1-5 vol percent SiC-coated MWCNTs and successfully sintered at 1800 deg C by means of pulsed electric current sintering. These composites showed superior microhardness of 30.6 GPa and toughness of 5.4 MPa m compared to monolithic SiC ceramics due to the improvement of adhesion between MWCNTs and the SiC matrix by the SiC coating. The microhardness and toughness of the monolithic SiC ceramics are 25.5 GPa and 4.8 MPa m~(1/2), respectively. The SiC-coated MWCNTs/SiC composites showed an interesting behavior with the elastic recovery when undergoing an indentation test.