Catalytic graphitization of fibrous and particulate carbons

Catalytic graphitization of carbon fibers, carbon black and anisopropic mesophase spheres by chromia and chromium compounds was studied to examine the influences of the amount of catalyst, procedures of catalyst dispersion and heating on the extent of graphitization. Catalyst addition as a liquid solution provided better dispersion than mixing of powdered catalyst with the carbons by grinding, and permitted graphitization of intact carbon fibers. However, the catalytic action caused restructuring of the fibers and the carbon black. Sequential heat treatments at temperatures < 2000°C were more effective for graphitization than higher temperature treatments in which the catalyst sublimed. In all cases the amount of graphitization increased sharply with the amount of catalyst. The mechanism of catalytic graphitization is briefly discussed.