SELF-ADHESIVE CARBON GRAINS OXIDATIVELY PREPARED FROM NAPHTHALENE-DERIVED MESOPHASE PITCH FOR MOLD OF HIGH-DENSITY

Self-adhesive carbonaceous grains for binderless mould were prepared through the oxidation treatment of the ground mesophase pitches catalytically synthesized from naphthalene with HF/BF3. The oxidation conditions strongly influenced the carbonization behaviors of the mesophase pitch grains and the strength of the resultant carbon artifacts (diameter: 20 mm, thickness: 4 mm). The oxidation at 493 K for 1-2 h in air flow was optimum to balance the fusibility and the thermosetting property of the mesophase pitch grains. The properly oxidized grains were proven to show self-adhesive ability, shape stability, and higher carbon yield, providing a carbon artifact of strikingly high density, 1.88 g/cm3, high compressive strength, 2.9-2.6 tf/cm2, and large shrinkage ratio, 33-42 vol% by the calcination at 1573 K. The observation using a polarized light optical microscope and SEM indicated fine-mosaic texture, dense packing, and sufficient adhesion of the grains in the carbonized artifact.