Low-temperature processing of B4C-Al composites via infiltration technique

An infiltration technique is commonly used for the fabrication of B4C-Al composites. However, due to the low wettability of aluminum on B4C, the process is currently performed at a relatively high temperature (1200 degreesC) in industries. As a result, a large amount of reaction products are formed in the system, causing a significant loss of the initial B4C and Al which are required for practical applications. In this study a sol-gel technique was employed to coat the B4C powders with TiO2. A subsequent heat treatment produced TiB2 layers which enhance the wettability of Al. This process facilitated aluminum infiltration at or below 1000 degreesC. In addition, this low-temperature process suppressed the formation of various reaction phases including deleterious Al4C3 It was also noted from the measurements of mechanical properties that the influences of undesirable reaction phases are considerably reduced. (C) 2001 Published by Elsevier Science B.V.