Processing and properties of alumina–carbon nano fibre ceramic composites using standard ceramic technology

Multi-wall carbon nano fibres (MWCNFs) offer an alternative to multi-wall carbon nanotubes (MWCNTs) as conductive reinforcing phases in ceramic composites. The main differences being their lower cost and larger dimensions. Alumina (Al2O3) composite materials with up to 12.5 vol.% content of carbon nano fibres (CNFs) have been produced using standard ceramic processing technology and additives. A detailed description of the milling and dispersion procedure, which produces a homogenous dispersion of the CNFs in the Al2O3 microstructure is presented. Dense hot pressed ceramic–CNF composites produced thereof have been characterized for electrical and thermal conductivity, three point bending strength and microstructure. The composites show that a critical flaw size is introduced with the CNFs and the decrease in strength does not vary with increasing CNF content. The composites show a near linear increase in electrical conductivity as a function of CNF content. A slight decrease in the thermal conductivity with increasing CNF content was also observed.