Protective coating with reactive interlayer on reinforcement in silicon carbide composite

Abstract

A protective coating for a reinforcement phase exposed to molten silicon or silicon alloy infiltrant comprises, an inner layer material resistant to reaction with the molten infiltrant, an interlayer of a reactive material that reacts with the infiltrant to form compounds having a melting temperature greater than the infiltrant, and an outer layer material resistant to reaction with the molten infiltrant. Materials resistant to reaction with molten silicon are a metal carbide from the group consisting of carbides of titanium, hafnium, zirconium, and tantalum; a metal nitride from the group consisting of nitrides of boron, silicon, aluminum, titanium, zirconium, hafnium, niobium, and tantalum; a metal boride from the group consisting of borides of titanium, zirconium, hafnium, silicon, and aluminum, or combinations thereof. Another inner layer material resistant to reaction with molten silicon is a metal oxide that is an oxide of aluminum, yttrium, titanium, zirconium, hafnium, beryllium, silicon, lanthanum, scandium, or the rare earths. Another outer layer material is rhodium, iridium, metal that reacts with silicon to form a silicide, metal carbide, metal silicide, metal nitride, or metal boride. Suitable metal silicides are silicides of chromium, molybdenum, tantalum, titanium, tungsten, or zirconium. Materials reactive with the molten silicon are carbon, molybdenum, titanium, chromium, niobium, zirconium, iridium, and combinations thereof.

Dependencies are inferred from the claim text.