Preparation and microstructure of multi-wall carbon nanotubes-toughened Al2O3 composite

With multi-wall carbon nanotubes (MWNTs) as reinforcement, a 12 vol% MWNTs/alumina (Al2O3) ceramic composite was obtained by hot pressing. A fracture toughness of 5.55 +/- 0.26 MPa.m(1/2), 1.8 times that of pure Al2O3 ceramics, was achieved. Experimental results showed that the enveloping of carbon nanotubes (CNTs) with sodium dodecyl sulfate (SDS) is effective in changing the hydrophobicity of CNTs to hydrophilicity and improving the dispersion of CNTs in aqueous solution. Enveloped with SDS, CNTs can be homogeneously mixed with Al2O3 at a microscopic level by heterocoagulation. This mixing method can obviously improve the chemical compatibility between CNTs and Al2O3, which is important for enhancement of interfacial strength between them.