沥青基碳／碳复合材料压力浸渍—碳化机理分析

煤沥青是一种内部成分非常复杂的芳烃类混合物，含有许多稠环结构。由于其组成成分的复杂性导致其碳化过程的复杂。液态沥青向制件孔内的浸渍过程中，既要克服由于液态沥青表面张力所产生的阻力，还要克服制件内部孔隙中气体所产生的阻力。经研究表明，沥青在常压下碳化，大量含碳的低分子成分挥发出去,晃但造成碳化收率的降低，而且也影响了致密效率。沥青在高压下碳化，不但提高了碳化收率，而且也影响碳化过程，有利于基体碳向石墨结构的转变。

Analysis of Process of Densification of Pitch-Based Carbon-Carbon Composites

We used modulated coal tar pitch (CTP) as the precursor of matrix of carbon-carbon composite. We investigated the carbonization of modulated CTP under low and high pressure with thermal analysis, X-ray diffraction and microstructure analysis, etc. When modulated CTP carbonized under low pressure, a large number of small molecules containing carbon volatilized, reducing the carbon yield of modulated CTP and thus also reducing the densification efficiency of carbon-carbon composite. When modulated CTP carbonized under high pressure (such as 40 MPa), the carbon yield increased and the carbonization process benefited the structure transition of matrix from turbostratic to graphitic.