The influence of a magnetic field during carbonization on the microstructure and electrical conductivity of needle cokes

The influence of a magnetic field during thermal polycondensation and carbonization of intermediate coal tar pitch on the electrical conductivity of the resulting needle cokes was explored using a pressure vessel under an external magnetic field. The microstructure of the cokes was analyzed by X-ray diffraction and polarized light microscopy. The electrical conductivity was measured during the coke forming process. Results indicated that aromatic molecules were ordered under the magnetic field during carbonization, leading to an improvement in the microcrystalline structure and an increase in the electrical conductivity of the cokes. Resistance-temperature curves also indicated that the magnetic field can accelerate the polymerization rate and reduce the dependence of the polymerization on temperature, which can be explained by the Zeeman effect.