Effect of Al additive in Si slurry coating on liquid Si infiltration into carbon-carbon composites

Two-dimensional carbon-carbon composites (2D-C/C) applied with a pure Si pre-coating or a Si-6 wt.%Al pre-coating by dipping slurry method were heated above Si melting point to perform liquid Si infiltration. For pure Si slurry pre-coating, liquid Si excessively infiltrated into the CIC composite and many cracks were formed inside resulting in serious degradation of the flexural strength of the C/C composite. For Si-6 wt.%Al pre-coating, only a little amount of liquid Si infiltrated into the CIC composite and the flexural strength was mostly retained after performing liquid Si infiltration. No deleterious effect of the At additive on the formation of SiC conversion layer was found. (C) 2001 Elsevier Science Ltd. All rights reserved.