Effect of carbonization pressure on microstructure and morphology of pitch derived carbon

Pitch cokes are prepared by carbonization of mesophase pitch and normal pitch at different pressures. Polarized-light microscopy (PLM) and scanning electron microscopy (SEM) are used to observe the morphology of above cokes at different pressures. The results show that the pitch cokes have different morphologies at different pressures using PLM analysis. The mesophase pitch coke at low pressure and high pressure are mainly of small domains, domain and flow domain respectively. The normal pitch coke at low pressure and high pressure are mainly of acicular flow domain anisotropy, mosaics and small domains respectively. The result of SEM shows that the pores change from big pores in different sizes to small ones in uniform size along with increasing carbonization pressure for two types of pitches. When the carbonization pressure is 40 MPa, the morphology of mesophase pitch coke is mainly of layered structure and that of normal pitch is layered and grapy structure.