Analysis of the structure of a glassy carbon using the fourier transform technique

• Published in: Carbon (New York) 1973-01, Vol.11 (2), p.127-138
• Main Authors: Ergun, Sabri, Schehl, Richard R
• Format: Article
• Language: English
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/0008-6223(73)90063-8

The structure of a heat-treated (~3000°C) glassy carbon produced from a polymer of furfural alcohol has been studied by the Fourier inversion of scattering intensities obtained using AgKα 1 radiation. Using Cauchy's distribution, novel theoretical expressions have been developed for the Fourier transforms that take into account the effects of distortion and defects in the lattice in addition to termination effects. The cosine transform of the (002) reflections showed that stacking of layers is extensive but faulty, mean spacing between faults being ~ 21 Å. The mean interlayer spacing was found to be 3.42 ± 0.03 A ̊ , the value of 0.03 Å representing the semi-quartile range of the mean interlayer spacing. A detailed analysis of the Fourier transforms of the ( hk) reflections revealed that the sample studied is made up of distorted hexagonal rings. The distortion is severe enough to make it very difficult, if not to prohibit, precise definition of the two-dimensional lattice. Three different lattices (two involving quinoidal rings) have been found to explain the observed transforms equally well. The transform yielded a mean defect-free distance in the layers of ~ 86 Å. Compared to 37 Å indicated by the line-width of the (11) reflections, it is clear that distortion effects outweight the defect or layer size effects in the observed profile of the (11) reflections. In the absence of equations for intensity profiles of random layered lattices that take into account the distortion effects, the Fourier transform procedure outlined in this study constitutes the only method that permits an authentic structural analysis.