H₂O catalysis of aluminum carbide formation in the aluminum-silicon carbide system

Aluminum carbide was found to form catalytically at aluminum-silicon carbide interfaces upon exposure to water vapor. Samples, composed of approximately 2 nm thick layers of Al on SiC, were fabricated and reacted in vacuo, and analyzed using XPS. Enhanced carbide formation was detected in samples exposed to 500 Langmuirs H₂O and subsequently reacted for 600 s at 873 K. The cause of the catalysis phenomenon is hypothesized to be the weakening of silicon-carbon bonds caused by very strong bonding of oxygen atoms to the silicon carbide surface. Aluminum carbide formation is of interest because of its degrading effect on the mechanical properties of aluminum/silicone carbide reinforced metal matrix composites, as well as its effect on the electrical properties of aluminum metallizations on silicon carbide layers in microelectronic components.