HEAT-TREATED NANO-STRUCTURED SHUNGITE ROCKS AND ELECTROPHYSICAL PROPERTIES ASSOCIATED

Abstract

Shungite rocks of two different types were treated at ~ 1400 ◦C and a set of nanomaterials have been obtained. Among the different materials obtained were: carbon hollow fibers; spherical or ellipsoid particles; silicon carbide amorphous; crystalline nanofibers and nanoparticles having different morphologies; iron and iron silicide nanoparticles encapsulated into carbon shells. Measurements were performed for shielding effectiveness (SE) and the electrical conductivity (σ) of untreated and heat-treated shungite rocks. The shungite rock with dominated hyperfullerene carbon is remarkable for a two-fold increase in the σ and a 10 dB increase in SE with a slight decrease of the carbon content by 1.5 % in relation to the untreated sample. In contrast, the treated shungite rock with high SiC nanofiber content is characterized by a halving of the σ and a 10 dB decrease in SE with a decrease of the carbon content by 6 % relative to the original sample.