Carbon/graphite seal materials prepared from mesocarbon microbeads Original Research Article

Mesocarbon microbeads were molded at different pressures, and then heat-treated. The resulting carbonized/graphitized blocks were evaluated in terms of physical properties and textures to determine their potential as seal materials. In order to seek optimum technical conditions, different molding pressure and heat treatment temperatures (HTT) were investigated. Results indicated that the bulk density and compressive strength and flexural strength increased with the molding pressure. The highest compressive strength of 402 MPa was obtained by using the molding pressure of 200 MPa and then carbonized at 900 °C. With increased HTT, the volumetric shrinkage of the blocks increased, and reached 39.3% when graphitized at 2800 °C. X-ray diffraction patterns and scanning electron microscopy showed that the blocks molded at pressures over 100 MPa had a fine mosaic texture. However at lower molding pressures a coarse mosaic texture and many pores and cracks were found.