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

文件类型：PDF文档
文件大小：166K
Articles (200) suitable for use as high-temperature machine components include a substrate (202) and an environmental barrier coating (210) disposed over the substrate (202), where 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, and where the at least one 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). The intermediate layer (216) can include a barrier material that is substantially inert with respect to silica.