Ceramic compositions for thermal barrier coatings stabilized in the cubic crystalline phase

A method for preparing a thermal barrier coating on an underlying substrate, the method comprising the step of:

• A. forming a thermal barrier coating over the metal substrate by depositing a zirconia-containing ceramic composition so that the zirconia is stabilized in the cubic crystalline phase, the ceramic composition comprising:
• 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 ceramic composition;
• 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 ceramic composition;
• and
• 1. 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 ceramic composition;
• and
• b. tantala in an amount of from about 0.5 to about 10 mole % of the ceramic composition.

A zirconia-containing ceramic composition capable of providing a thermal barrier coating wherein the zirconia is stabilized in the cubic crystalline phase, and which comprises:

• 1. from about 50 to about 90 mole % zirconia;
• and
• 2. a stabilizing amount of from about 5 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 composition;
• b. optionally a second metal oxide selected from the group consisting of yttria, calcia, ceria, scandia, magnesia, india and mixtures thereof in an amount of about 0.1 mole % or less of the composition;
• 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 composition;
• and
• b. tantala in an amount of from about 0.5 to about 10 mole % of the composition.

A thermally protected article, which comprises:

• A. a substrate;
• and
• B. a thermal barrier coating that is stabilized in the cubic crystalline phase, and which comprises:
• 1. from about 50 to about 90 mole % zirconia;
• and
• 2. a stabilizing amount of from about 5 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 thermal barrier coating;
• b. optionally a second metal oxide selected from the group consisting of yttria, calcia, ceria, scandia, magnesia, india and mixtures thereof in an amount of about 0.1 mole % or less of the thermal barrier coating;
• 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 thermal barrier coating;
• and
• b. tantala in an amount of from about 0.5 to about 10 mole % of the thermal barrier coating.