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将聚丙烯腈基炭纤维在石墨化炉中维持定长加热,以模拟炭/炭复合材料制备过程中炭纤维结构的变化,并采用小角X射线散射(SAXS)和高分辨透射电子显微镜(HRTEM)检测石墨化过程中的结构演变。随着温度的提高炭纤维中微孔的平均回转半径、长度、宽度、截面积和体积分数呈现先减小后增大的趋势,并在约2300℃出现极小值。炭纤维中孔隙尺寸的变化与炭层片的活动性密切相关。炭层的缩合和有序化导致孔隙率的减小,而炭层在更高温的簇状化导致孔隙尺寸的增大。
The polyacrylonitrile-based carbon fibers were heated in a graphitizing furnace for the purpose of simulating the carbon fiber structure changes during the preparation of the carbon / carbon composites. Small angle X-ray scattering (SAXS) and high resolution transmission electron microscopy (HRTEM) ) To detect the structural evolution during graphitization. The average radius of gyration, length, width, cross-sectional area and volume fraction of micro-pores in carbon fiber tend to decrease and then increase with the increase of temperature, and the minimum appears at about 2300 ℃. The change of pore size in carbon fiber is closely related to the activity of carbon sheets. Condensation and ordering of the carbon layers leads to a reduction in porosity, while clustering of the carbon layers at higher temperatures leads to an increase in pore size.