title: A novel structure for carbon nanotube reinforced alumina composites with improved mechanical properties.
abstract: Engineering ceramics have high stiffness, excellent thermostability, and relatively low density, but their brittleness impedes their use as structural materials. Incorporating carbon nanotubes (CNTs) into a brittle ceramic might be expected to provide CNT/ceramic composites with both high toughness and high temperature stability. Until now, however, materials fabrication difficulties have limited research on CNT/ceramic composites. The mechanical failure of CNT/ceramic composites reported previously is primarily attributed to poor CNT-matrix connectivity and severe phase segregation. Here we show that a novel processing approach based on the precursor method can diminish the phase segregation of multi-walled carbon nanotubes (MWCNTs), and render MWCNT/alumina composites highly homogeneous. The MWCNTs used in this study are modified with an acid treatment. Combined with a mechanical interlock induced by the chemically modified MWCNTs, this approach leads to improved mechanical properties. Mechanical measurements reveal that only 0.9 vol% acid-treated MWCNT addition results in 27% and 25% simultaneous increases in bending strength (689.6 ± 29.1 MPa) and fracture toughness (5.90 ± 0.27 MPa m(1/2)), respectively.
authors.affiliation: Institute of Fluid Science, Tohoku University, Sendai 980-8577, Japan. Graduate School of Environmental Studies, Tohoku University, Sendai 980-8579, Japan.
authors.forename: G
authors.initials: G
authors.lastname: Yamamoto
authors.forename: M
authors.initials: M
authors.lastname: Omori
authors.forename: T
authors.initials: T
authors.lastname: Hashida
authors.forename: H
authors.initials: H
authors.lastname: Kimura