炭化压力对沥青成焦形貌及航空刹车用C/C复合材料浸渍增密效果的影响

将武钢中温沥青和太钢高温沥青在不同压力下炭化，进一步对所得沥青焦进行了高温热处理，利用扫描电子显微镜（SEM）和光学显微镜观察所得沥青焦形貌。结果表明；低压炭化时，沥青焦体积密度小，疏松、多大孔，主要为流线区域型各向异性结构；高压炭化时，沥青焦体积密度明显变大，孔变小且均匀分布，主要为小区域和细镶嵌型各向异笥显微结构。考察了不同炭化压力对浸渍增密航空刹车用C／C复合材料的增密效率的影响，结果显示，对整个沥青而言的宏观残炭率明显高于只针对样品而言的实际残炭率，因此有必要进行高压浸渍／炭化实现快速增密。利用XRD和显微硬度测试仪检测了不同炭化压力所得沥青焦热处理后的石墨化度和显微硬度，发现高压下形成的沥青炭更难于石墨化，但石墨化度与显微硬度的热处理后的粗糙层（RL）CVD炭有较好的可比性。

EFFECT OF CARBONIZATION PRESSURE ON THE MORPHOLOGY OF ITCH DERIVED CARBON AND DENSIFICATION EFFICIENCY OF C/C COMPOSITES USED FOR AIRCRAFT BRAKES

Pitch cokes were prepared by carbonization of pitches from Wuhan Iron and Steel Plant and the Taiyuan Iron and Steel Plant under different pressures and heat treatments. Scanning electron microscopy (SEM) and polarized light microscopy were used to observe the morphology of the pitch derived carbon before and after graphitization. The results indicated that the pitch coke produced by low carbonization pressure was mainly of the flow domain anisotropy type with low bulk density, while the one resulting from high pressure was mainly coarse grained mosaic or fine grained mosaic with higher bulk density. X ray determination of the graphitization degree and microindentation hardness test showed that pitch derived carbon was comparable to rough laminar type CVD derived carbon to some extent and the pitch could be used as a precursor for the matrix of C/C composites. Results of densifying C/C composites under different pressure proved that densification efficiency was determined by carbon yield depending on the specimen, and relatively high pressure was needed to shorten the production time.