Abstract
Pitch Carbon is a binderless-carbon product which is prepared from variant pitch material (VPM).The present work was undertaken to elucidate how a small amount of soluble components in VPM influences on the properties of resulting Pitch Carbon. VPM was prepared by heating coal tar pitch up to 550°C bubbling nitrogen gas through it.It contained 0.5% of benzen soluble component, 1.8%R of quinoline soluble component and 0.5% of volatile component through heating under reduced pressure of 3 mmHg at 350°C for 1 hour. After pulverizing to-100 mesh, the VPM was further treated to cover the VPM particles with soluble components and to change the soluble component content in it. Eight kinds of VPMs thus prepared were moulded into pellet (20 mm∅ and several mm in thickness) under 1000 kg/cm2 and then heated at 1000° and 2800°C.
The soluble components covering VPM particles caused Pitch Carbon to decrease density and hardness.This decrease was more marked in Pitch Carbon from the VPM particles covered with thicker soluble component layer.It became apparent from the microscopic observations that through the heat-treatment process, the soluble components covering VPM particles decompose to result in formation of porous carbon between VPM particles and/or to form gaps along VPM particle surface.These phenomena causes Pitch Carbon to make less dense and less hard. The VPM free from soluble component gave Pitch Carbon having almost same properties as that from the VPM with no specific treatment.The causes of these phenomena are discussed.
