碳布缝合预制体孔隙与热解碳沉积时变相依的多尺度研究

Multi-Scale Relationship of Pores in Carbon Cloth Stitched Preform and Deposition of Pyrocarbon

以甲烷为前驱体,碳布缝合织物为预制体,采用等温化学气相渗透(ICVI)工艺,在1 368 K温度和1 s滞留时间下制备了C/C复合材料。采用压汞仪表征不同致密化时间下预制体的孔隙分布,采用偏光显微镜观察热解碳的结构。结果表明:预制体的孔隙分布呈现多峰分布,热解碳的沉积速率与[A/V]值成反比,热解碳的结构与预制体的比表面积相关,沉积初期比表面积较大时,得到的热解碳织构为各相同性和低织构热解碳,随着沉积的进行,比表面积逐渐减小,在纤维束的边沿等部位出现了高织构热解碳。

Isothermal chemical vapor infiltration（ICVI） was used to study carbon cloth stitched preform densifi- cation process,methane was the precursor, at the temperature of 1 368 K and residence time of 1 s. Carbon cloth stitched preform porosity distribution under different time was characterized by mercury porosimetry, and the pyrocar- bon structure was observed by PLM. It is found that the porosity presented multipeek shape, and pyrocarbon deposition rate and [A/V] value showed a inverse correlation throughout the whole study process. The texture of the pyrocarbon had a relationship with the specific surface area. Isotropic and low textured pyrocarbon was first got at the initial of in- filtration, then high textured pyrocarbon was discovered at larger size pores like the edge of the bundle.