Effects of Carbonization Pressure on Microstructure of Graphitized Pitch-derived Carbons

Graphitized pitch-derived carbons were prepared under carbonization pressures of 30MPa and 60MPa respectively,using high temperature pitch as raw material.Microstructure of the samples were investigated by SEM and TEM.Results indicate that the samples prepared at 30MPa and 60MPa are dominated by easy graphitized flow/flow domain type texture and non-graphitized mosaic/domain type texture,respectively.Nucleation,growth and amalgamation of carbonaceous mesophase spherule as well as microstructures of as-prepared materials are influenced by carbonization pressures.Carbonaceous mesophase spherule can amalgamate completely to form anisotropic flow type texture at the carbonization pressure of 30MPa,while amalgamation of carbonaceous mesophase spherule is blocked to form mosaic type texture at the carbonization pressure of 60MPa.TEM and SAED results show that main texture of the sample prepared at 30MPa is flow type texture,some isotropic textures exist at the rim of lamellar structures or among them.Samples prepared at 60MPa exhibit non-homogeneous microstructure where(002) rings distribute by spotted state.It can be concluded that uniformity and orientation of the sample prepared at 30MPa are better than those of the sample prepared at 60MPa.