Mechanical properties and structural characterization of carbon nanotube/alumina composites prepared by precursor method

Multi-walled carbon nanotubes/alumina composites were prepared by precursor method. Here, the distilled water with a small amount of surfactant (2,2,2-nitrilotriethanol) was used as a dispersing agent for MWCNTs. In order to evaluate the effects of MWCNT addition on mechanical properties and micro/nanostructure of the resultant composites, we employed two sets of the composites having different sintering additives (silica and magnesia). XRD analysis revealed that MWCNT/alumina composites were successfully synthesized by the dehydration of aluminum hydroxide-MWCNTs mixture at 1500 °C during spark plasma sintering. However, fracture property tests have shown that no improvement of the bending strength and fracture toughness of both the composites was achieved by addition of MWCNTs. According to the fracture property tests and SEM data, in conjunction with the relationship between porosity and bending strength, the MWCNT aggregate in the matrix may possess no load-carry ability.