Contact-damage-resistant ceramic/single-wall carbon nanotubes and ceramic/graphite composites

Nat Mater. 2004 Aug;3(8):539-44. doi: 10.1038/nmat1161. Epub 2004 Jul 18.


There has been growing interest in incorporating single-wall carbon nanotubes (SWNTs) as toughening agents in brittle ceramics. Here we have prepared dense Al(2)O(3)/SWNT composites using the spark-plasma sintering (SPS) method. Vickers (sharp) and Hertzian (blunt) indentation tests reveal that these composites are highly contact-damage resistant, as shown by the lack of crack formation. However, direct toughness measurements, using the single-edge V-notch beam method, show that these composites are as brittle as dense Al(2)O(3) (having a toughness of 3.22 MPa m(0.5)). This type of unusual mechanical behaviour was also observed in SPS-processed, dense Al(2)O(3)/graphite composites. We argue that the highly shear-deformable SWNTs or graphite heterogeneities in the composites help redistribute the stress field under indentation, imparting the composites with contact-damage resistance. These composites may find use in engineering and biomedical applications where contact loading is important.

Publication types

  • Comparative Study
  • Evaluation Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Aluminum Oxide / chemistry*
  • Ceramics / chemistry*
  • Crystallization / methods*
  • Elasticity
  • Hardness
  • Hardness Tests / instrumentation
  • Hardness Tests / methods
  • Manufactured Materials
  • Materials Testing / instrumentation
  • Materials Testing / methods*
  • Nanotechnology / instrumentation*
  • Nanotechnology / methods*
  • Nanotubes, Carbon / chemistry*
  • Nanotubes, Carbon / ultrastructure
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Shear Strength
  • Surface Properties


  • Nanotubes, Carbon
  • Aluminum Oxide