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对于各种常用的聚粒状人造碳或石墨来说,都要求是高密度材料,因为它们的渗透性低、机械性能高。由250℃左右的煤焦油沥青熔体浸渍经800℃预处理的碳基体可达到这种致密化。常压下,100～300℃范围内再加热浸渍材料时,熔融沥青出现较大的回流,这种现象称为“热渗析”。加热至800℃后,初始浸入的沥青只有30wt％以焦炭形式残存在孔隙中。那些原因引起热渗析?如何防止或减少这种现象? 乍看起来,热渗析可能涉及许多物理参
High density materials are required for a variety of commonly used aggregates of synthetic carbon or graphite because of their low permeability and high mechanical properties. This densification can be achieved by impregnating a coal matrix pretreated at 800 ° C with a coal tar pitch melt at about 250 ° C. Atmospheric pressure, 100 ~ 300 ℃ reheat the impregnated material within the range, the melt bitumen appears a larger reflux, a phenomenon called “thermal dialysis.” After heating to 800 ° C, only 30% by weight of the initially impregnated bitumen remains in the pores as coke. What causes thermal dialysis? How do you prevent or reduce this? At first glance, thermal dialysis may involve many physical parameters