TANSO

Relationship between coefficient of thermal expansion and physical properties of carbon solids made from various cokes has been investigated. The samples selected include needle-like cokes which are used commercially as the filler in the manufacture of (ultra) high power graphite electrode.
Changes in the bulk density, coefficient of thermal expansion, intensity of (002) X-ray diffraction peak and pore distribution measured with mercury porosimetry for carbon solids after heat treatment at baking and graphitizing temperatures are presented. The coefficient of thermal expansion is related to the orientation of crystallites, the total pore volume and the transitional pore volume for both the calcined cokes and graphitized solids.
The microstructures has been observed using a polarized light microscope. Shrinkage cracking running parallel to needle-like layer is one of the important factors governing the thermal expansion.

View full abstract

Show abstractHide abstract

This paper deals with the changes of X-ray parameters in graphitization process and the relations among them. Thirteen aromatic compounds were used as the raw materials and were heat-treated at 1000°C, 2000°C, 2400°C and 2800°C under nitrogen. The relations between the heat-treatment temperature and X-ray parameters varied to great extent depending on the king of aromatic compounds used as the raw materials. Tetrabenzo (a, c, h, j) phenazine gave the most graphitizing carbon, and phenolphthalein gave a typical nongraphitizing one. Carbons prepared from other compounds, 1, 8-diaminochrysazine, 1, 5-diaminoanthrarufin, violanthrone, pyranthrone, dibromo-pyranthrone, polyphenylene, dichloro-iso-violanthrone, dichloro-violanthrone and dimethoxy-violanthrone, lied between the above two materials. On the basis of these results and the relations among the parameters, it has been found that the graphitizability of carbons prepared from the aromatic compounds depends chiefly on the degree of flatness of the molecules and on the fusibility of the compounds.

View full abstract

Download PDF (689K)

Register with J-STAGE for free!