Patent ID: 7968217

Claim:
An article comprising: a substrate; and a self-sealing and substantially hermetic sealing layer disposed over the substrate, wherein the sealing layer comprises a rare-earth aluminosilicate, wherein the rare earth aluminosilicate has a composition in the range bounded by a region in alumina/silica/rare-earth oxide compositional space defined by a first line connecting a first composition point at (10 mole % alumina, 62 mole % silica, 28 mole % rare-earth oxide) with a second composition point at (40.5 mole % alumina, 48.5 mole % silica, 11 mole % rare-earth oxide); a second line connecting a third composition point at (58.3 mole % alumina, 27.8 mole % silica, 14 mole % rare-earth oxide) with a fourth composition point at (24.5 mole % alumina, 42.5 mole % silica, 33 mole % rare-earth oxide); a third line connecting the first composition point with the fourth composition point; and a fourth line connecting the second composition point with the third composition point.