Hejun Li
材料科学技术（英）
2D needle-punched fiber felt was infiltrated by a kind of rapid isothermal chemical vapor infiltration technique.
The infiltration process and texture transition of the infiltrated C/C composites were investigated. The porosity
and the variations of the cumulative pore volume were determined by mercury porosimetry. The texture of
matrix carbon was studied under a polarized light microscope. The results show that the relative mass gain
of the sample increases directly as the infiltration time at the initial stage until 20 h, and subsequently the
increasing rate of the relative mass gain decreases gradually with the prolonging of infiltration time. Three layers
of pyrocarbon were formed around fibers. Low-textured pyrocarbon was obtained at the initial stage. With the
densification going on, high-textured pyrocarbon was formed on the surface of low-textured pyrocarbon. Then,
low-textured pyrocarbon was produced again during the final stage of densification. The texture transition is
ascribed to the variation of the ratio of cumulative inner surface area to volume of pores and the gas partial
pressure in pores.
关键词:
C/C composites
,
Isothermal chemical vapor infiltration (ICVI)
,
Pyrocarbon
,
Mercury porosimetry
,
Polarized light microscope
