Abstract:
A method for increasing density and strength in baked carbonaceous products such as carbon or graphiteelectrodes. A baked carbonaceous body is subjected to a conventional pitch impregnation, and is then coated with a thermosetting polymerizable composition, which composition is at least partially cured to provide an encasing shell of polymeric material. The shell-encased body containing impregnated pitch is thereafter subjected to carbonization by rebaking. During rebake, the shell is mechanically stable to temperatures above the softening and free flowing temperatures for the impregnant, whereby the shell (which is decomposed and carbonized as higher temperatures are attained) acts during initial stages of carbonization to retain the impregnant within the body. This results in larger quantities of coked impregnant remaining in the body with consequent higher apparent density and strength in the resultant product. The product can then, as desired, by subjected to a conventional heating schedule to effect graphitization.