Fabrication and mechanical evaluation of aligned multi-walled carbon nanotube sheet/alumina laminated ceramic composites

Here we present a simple way of preparing an alumina ceramic material that contains aligned multi-walled carbon nanotube (MWCNT) layers, i.e., aligned MWCNT sheet/alumina laminated ceramics are prepared for the first time by using a filtration technique and spark plasma sintering (SPS) method. It is demonstrated that the introduction of the aligned MWCNT sheets is an effective approach to deflect cracks preventing catastrophic failure whilst raising the fracture toughness from 3.81 ± 0.09 MPa·m^1/2 to 4.10 ± 0.10 MPa·m^1/2 and work required to break the samples from 43 ± 7 J/m² to 256 ± 70 J/m². The electrical conductivities of the composites, containing 0.7 vol.% aligned MWCNT sheets, in directions both parallel and perpendicular to the MWCNT alignment reach values of 858.5 S/m and 117.2 S/m, respectively, compared with that of 10^-10-10^-12 S/m for monolithic alumina samples.