中文摘要：

控制生坯在焙烧过程中的体积膨胀是制备优良性能石墨的关键因素。通过采用不同温度成型,研究了它们在焙烧过程中的膨胀机理。结果表明：170℃模压成型生坯在焙烧过程中的膨胀现象符合＂气压＂膨胀机理,生坯气体渗透性差,在沥青高温分解过程中易引起凸起、裂纹等表面形变,通过降低焙烧升温速率可以抑制焙烧过程中产生的膨胀;而135℃模压成型生坯,在焙烧过程中膨胀现象符合残余应力松弛-＂气压＂膨胀复合机理,气体渗透性比170℃制备的生坯好,膨胀主要发生在沥青软化阶段,采用适当的成型压力和较低焙烧升温速率可以提高焙烧品性能。

英文摘要：

Controlling the volumetric dilation during baking is a key factor in the preparation of excellent graphite and carbon materials.The mechanism of expansion of shaped carbonaceous products at different forming temperatures during baking was investigated.Results showed that the green body hot-pressed at 170 ℃ can easily form a convex surface,cracks and other deformations during baking,which is in accordance with the gas dilation mechanism because of the poor gas permeability of the green body.The expansion and deformation can be inhibited by lowering the heating rate during baking.The expansion of the green body hot-pressed at 135 ℃ was caused by both the relaxation of residual stress and the gas dilation mechanism.The gas permeability of green body hot-pressed at 135 ℃ is superior to that hot-pressed at 170 ℃ and the dilation of the former mainly occurred at the pitch softening stage,and was also affected by heating rate during baking.The performance of the baked products can be improved by optimizing pitch/carbon ratio,molding temperature and pressure and by lowering the heating rate during baking.