Capillary infiltration studies of liquids into 3D-stitched C-C preforms Part A: Internal pore characterization by solvent infiltration, mercury porosimetry, and permeability studies

摘要

Mathematical modeling of silicon infiltration in porous carbon-carbon (C-C) preforms is the key to fabricate liquid silicon infiltration based carbon-silicon carbide (C-SiC) composite components. Existing models for silicon infiltration are based on straight capillaries. For interconnected capillary systems, e.g. as in 3D-stitched C-C preforms these show large deviations when compared with experimental observations. The aim of the present study is to develop a mathematical model suitable for silicon infiltration in 3D-stitched C-C preforms. The work is being presented in two parts: A and B. This part (Part A) describes the experimental details pertaining to the fabrication of the C-C preforms and their pore structure characterization by mercury porosimetry, infiltration of solvents by capillary rise, and by permeability studies. A two-pore capillary infiltration model termed as modified Washburn equation has been proposed. It has been validated by experimental data of solvent infiltration. The same model correlates silicon infiltration observations as well (Part B).