Patent ID: 7364807

Claim:
An article comprising: a substrate comprised of a silicon containing material; an environmental barrier coating (EBC) overlying the substrate; and a thermal barrier coating (TBC) on the environmental barrier coating, said thermal barrier coating comprising a compound consisting essentially of a rhombohedral phase, wherein said compound has the formula of: A 4 B 3 O 12 , wherein A comprises at least one rare earth element; and B is selected from the group consisting of Zr, Hf and mixtures thereof, said TBC comprises a primary constituent portion and a stabilizer portion, said stabilizer portion of said TBC comprises an oxide of said at least one of rare earth element A, said primary constituent portion of said TBC consists of an oxide of B, to produce a stabilized hafnia, a stabilized zirconia or a mixture thereof on the EBC and wherein said primary constituent portion consists of hafnia or a mixture of zirconia and hafnia, or zirconia.