Patent ID: 6887595

Claim:
A thermal barrier coating, which comprises: A. a zirconia-containing upper layer wherein the zirconia is stabilized in the cubic crystalline phase, and which comprises: 1. at least about 50 mole % zirconia; and 2. a stabilizing amount up to about 49 mole % of a stabilizer component comprising: a. a first metal oxide selected from the group consisting of ytterbia, neodymia, mixtures of ytterbia and neodymia, mixtures of ytterbia and lanthana, mixtures of neodymia and lanthana, and mixtures of ytterbia, neodymia and lanthana in an amount of from about 5 to about 49 mole % of the upper layer; and b. a second metal oxide selected from the group consisting of yttria, calcia, ceria, scandia, magnesia, india and mixtures thereof in an amount of about 4 mole % or less of the upper layer; and 3. one or more of a third metal oxide selected from the group consisting of: a. hafnia in an amount from about 0.5 to about 40 mole % of the upper layer; and b. tantala in an amount of from about 0.5 to about 10 mole % of the upper layer; and B. a zirconia-containing lower layer wherein the zirconia is stabilized in the tetragonal crystalline phase, and which comprises: 1. at least about 80 mole % zirconia; 2. a stabilizing amount up to about 10 mole % of a stabilizer component, which comprises: a. a first metal oxide selected from the group consisting of yttria, calcia, ceria, scandia, magnesia, india and mixtures thereof in an amount of from about 1.5 to about 6 mole %; and b. a second metal oxide selected from the group consisting of lanthana, neodymia, ytterbia and mixtures thereof in an amount of from about 0.5 to about 8.5 mole %.