Effect of heating rate, temperature, and residence time during graphitization on the mechanical and electrical properties of isotropic graphite blocks

The present study aimed to determine the correlation between graphitization parameters during the manufacturing of isotropic graphite blocks, including temperature, residence time, and heating rate, and the physical properties of the obtained graphite blocks. It was found that during graphitization, nitrogen- and sulfur-containing gases were generated, and the isotropic graphite blocks exhibited volume shrinkage, and their apparent density and bulk density increased, regardless of any changes in the process parameters, due to the intrinsic microstructure of the isotropic coke. Graphite blocks with varying graphitization temperatures and residence time exhibited increased bulk density and open porosity but decreased flexural strength and electrical resistivity compared to carbonized blocks. It was also confirmed that the heating rate process parameter was related to gas release rates and crystallization. In addition, it was observed that micron-sized pores were created around the developed graphite layered structure with increasing graphitization degree.