The addition of multi-wall carbon nanotubes (MWCNTs) to ceramic matrices could provide nanocomposites with enhanced properties. Efforts to produce these materials are normally frustrated by two major issues: firstly, the difficulty of attaining a homogenous distribution of MWCNTs in the matrix and secondly the poor bonding between the MWCNTs and the ceramic matrix. Herein, a processing method that overcomes these problems by using a solegel route to produce a low-melting point silica matrix, in combination with a dispersion method for the MWCNTs that is compatible with the sol is reported. This
universal method was used to coat mesoporous silica on conventional, nitrogen-doped (CNX) and borondoped (CBX) produced using aerosol assisted chemical vapour deposition (AACVD) as well as commercially available MWCNTs. After hot-pressing the powders, record improvements (ca. 50%) in hardness for the nanocomposites over the silica were observed and this improvement is enhanced by 50% if spark plasma sintering is used to consolidate the nanocomposites. Nanocomposites containing conventional nanotubes produced from AACVD and commercially available nanotubes have near identical hardness even though the nanotubes have different properties and characteristics.