Characterisation of carbon fibres grown from carbonaceous gases by measurements of their density and oxidation resistance

In the present work it has been demonstrated, by measurements of their dens ity and air oxidation resistance, that different sorts of carbon fibres gro wn from a gaseous stage, vapour grown carbon fibres (VGCF), present a duple x structure. By means of these two experimental techniques, structural diff erences between both constituent phases of this kind of fibres have been de termined. It has been proved that the catalytic phase or nucleus presents h igher level of crystalline perfection than the pyrolytic or cortical phase. This is corroborated by the fact that thin VGCF show better mechanical pro perties than thick fibres.