Carbon disc of high density and strength prepared from synthetic pitch-derived mesocarbon microbeads

Binderless carbon discs were prepared from mesocarbon microbeads (MCMB) derived from the synthetic naphthalene pitch without and with carbon black. The carbonized discs were evaluated in terms of physical properties and textures. Carbon black included in the stabilized MCMB was found to enhance significantly the compressive strength of the disc by suppressing the formation and propagation of the fissures and voids in the disc. Strikingly high compressive strength of 420 MPa, bulk density of 1.71 g/cm(3), and large volumetric shrinkage of 33% were successfully obtained by calcining the disc at 1300 degrees C, which were prepared from the stabilized MCMB with 3% BP2000 (Black Pearls 2000). The. disc of no stabilization without carbon black exhibited a flow texture with large voids and deformed shape. Oxidative stabilization at 300 degrees C for 1 h provided the fine mosaic texture in the disk with the excellent shape stability and homogeneous shrinkage. The discs from MCMB with BP2000 and KB (Ketjen Black) stabilized at 270 degrees C for 1 h showed the intimate adhesion among MCMB particles with homogeneous texture, no large fissure being found in the calcined disc, corresponding to their higher mechanical strength. No stabilization of MCMB with carbon black provided inferior strength and shape stability to that of stabilized MCMB with carbon black, but much superior to those of MCMB without carbon black regardless of the stabilization. (C) 1999 Elsevier Science Ltd. All rights reserved.