Valery Khabashesku
University of Houston, USA
Title: Pressure-temperature-induced transformations of hydrocarbon-fluorocarbon mixtures into nano- and micron-size diamonds
Biography
Biography: Valery Khabashesku
Abstract
Studies of thermal transformations of naphthalene, octafluoronaphthalene and their binary mixtures under pressure of 8 GPa have been undertaken as models for gaining understanding of processes of carbonization, graphitization and diamond formation in pure hydrocarbon, fluorocarbon and carbon-hydrogen-fluorine-containing systems under high pressures. The studies found a significant reduction in the initiation temperature thresholds for all major thermal transformation processes in case of binary mixtures with respect to thresholds for pure naphthalene and fluoronaphthalene. The naphthalene-octafluoronaphthalene mixture was selected as an example for investigation of the nature of large scale formation of micro (5-20 μm) and nanosize (10-20 nm) fractions of diamond in the transformations of binary mixtures of hydrocarbon and fluorocarbon compounds under high pressures. The origin of nanodiamond was found to be due to the specifics of carbonization of fluorocarbon compounds under pressure, which at 800-1000 °Ð¡ produces, along with submicron particles of graphite-like material, a significant amount of closed shell 2-5 layer carbon nanoparticles of 5-15 nm size. These carbon nanoparticles act as precursors for formation of nanosize diamond fractions in the transformations of binary mixtures of hydrocarbon and fluorocarbon compounds. These results potentially open a new direction for metal catalyst-free synthesis of nano/micro-size fractions of pure and doped diamonds for broad areas of applications.