ARTICLES HAVING REDUCED EXPANSION AND HERMETIC ENVIRONMENTAL BARRIER COATINGS AND METHODS FOR THEIR

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PROBLEM TO BE SOLVED : To provide articles having reduced expansion and hermetic environmental barrier coatings useful as a barrier to water vapor and other detrimental substances, and methods for their manufacture. SOLUTION : Articles 200 suitable for use as high-temperature machine components include a substrate 202 and an environmental barrier coating 210 disposed thereover. The environmental barrier coating 210 includes at least one hermetic self-sealing layer 212 formed from a mixture including an alkaline earth metal aluminosilicate and a rare-earth silicate. The hermetic self-sealing layer 212 exhibits substantially no net remnant or residual expansion when subjected to high temperature heat treatment. The environmental barrier coating 210 can further include a bondcoat 204 disposed between the substrate 202 and the hermetic self-sealing layer 212, a topcoat 214 disposed over the hermetic self-sealing layer 212, and/or an intermediate layer 216 disposed between the hermetic self-sealing layer 212 and the bondcoat 204. COPYRIGHT : (C)2016, JPO&INPIT