On fractal nature of the structure of nanoporous carbon obtained from carbides

The curves describing small-angle x-ray scattering at npor-C nanoporous car bon samples obtained from polycrystalline alpha-SiC, TiC, and Mo2C and a 6H -SiC single crystal have been analyzed. An algorithm is developed for takin g into account the corrections to experimental curves for the intensity of the primary beam transmitted through the sample and the height of the inlet slit in these measurements. Two systems of nanoclusters observed in the np or-C structure differ in the type of stacking of structural elements: small -scale mass fractals of a dimension 1 < D-2 < 3 and a size L-2 = 50-90 Angs trom, which depend on the type of the initial carbide, and large-scale nano clusters having a size L-1 > 550 Angstrom. In most samples, large-scale nan oclusters can be regarded as objects with a fractal surface and a dimension 2 < D-1 < 13, which also depends on the type of the initial carbide. Large -scale nanoclusters in npor-C obtained from Mo2C prove to be mass fractals with a dimension D-1 > 2. Peculiarities of the structure formation of nanop orous carbon obtained from various carbides are discussed. (C) 2000 MAIK "N auka /Interperiodica".