Modification of the Nanoglobular Structure of Glassy Carbon by Heat Treatment and Ion Irradiation

The results of a comparative experimental study of the structure and morphology of high-temperature glassy carbon of brand SU-2500 after high-fluence (10(18) cm(-2) and higher) irradiation with 30-keV Ar+ ions in the temperature range of 60-600 degrees C and glassy carbon samples after treatment at temperatures of 850, 1300, 2000, and 2500 degrees C are reported and discussed. The Raman spectra of irradiated glassy carbon SU-2500 show the amorphous state of the surface layer after irradiation at temperatures below that of dynamic annealing of radiation damage, which is determined from the temperature dependence of the ion-induced electron emission yield, a graphite-like state after irradiation at temperatures of 150-250 degrees C, and a structure typical of glassy carbon samples treated at elevated temperatures after irradiation at temperatures in the range of 250 < T <= 600 degrees C. Ion irradiation under conditions of the dynamic annealing of radiation damage leads to a cellular topography, i.e., nanowalls connected by nodes. The sizes of the structure cells are about 150 and 300 nm after irradiation at temperatures of 250 and 600 degrees C, respectively.