Abstract: An article comprising a silicon carbide and/or silicon metal-containing substrate and an environmental barrier layer overlaying the substrate, wherein the environmental barrier layer has a thickness up to about 5 mils (127 microns) and comprises a reaction-generated corrosion resistant metal silicate. A process is also provided for reacting a metal source and a silica source over the silicon carbide and/or silicon metal-containing substrate to form the environmental barrier layer comprising the reaction-generated corrosion resistant metal silicate.

Abstract: An article comprising a substrate and a plurality of coating units disposed over the substrate is provided. Each coating unit comprises an oxygen-getter layer and a barrier layer. Embodiments of the present invention introduce redundancy to enhance the robustness of a coating system. Multiple protective coating units are disposed over a substrate so that failure of one of the coating units will be far less likely to subject the substrate to direct risk of exposure to the environment. Failure of an outer coating unit merely exposes a pristine protective coating unit, rather than the substrate or a less protective coating layer. In this way, embodiments of the present invention drastically reduce reliance on the performance of one particular coating layer, promoting a more robust and reliable system.

Abstract: Articles for use in a high temperature environment, and methods for protecting articles in such environments, are provided. The article comprises a substrate comprising silicon; a bondcoat comprising silicon, disposed over the substrate; an intermediate barrier disposed over the bondcoat, the barrier comprising at least one layer, wherein the at least one layer comprises a rare-earth silicate and is substantially free of mullite; and a topcoat disposed over the intermediate barrier, the topcoat comprising a rare-earth monosilicate. The method comprises providing a substrate, the substrate comprising silicon; disposing a bondcoat comprising silicon over the substrate; disposing an intermediate barrier over the bondcoat, the barrier comprising at least one layer, wherein the at least one layer comprises a rare-earth silicate and is substantially free of mullite; and disposing a topcoat over the intermediate barrier, the topcoat comprising a rare-earth monosilicate.

Abstract: A coating for silicon based materials such as those used in high temperature, aqueous environments. An aspect of the invention is directed to an article including a silicon based substrate, a bond coat comprising silicon, and a barrier coat. The barrier coat includes an aluminate such as an alkaline earth metal aluminate or a rare earth aluminate. The barrier coat may be an intermediate coat between the bond coat and a top coat, or it may be the top coat.