Rare-earth oxide coatings for refractory alloys, methods of manufacturethereof and articles comprising the same

A method of disposing a thermal barrier coating on a turbine airfoil, the method comprising:

• blending metal oxides in a blender to form a composition having the formula (1)
• (M1(1-a-b-c-d, . . . n)M2aM3bM4c..MNn)2O3(1), where the subscript “a” represents the molar fraction of element M2, “b” represents the molar fraction of element M3, “c” represents the molar fraction of element M4, and “n” represents molar fraction of element MN (in the metal oxide of formula (1));
• and where the sum of a+b+c+d+ . . . +n is less than 1;
• where M1 represents a base element derived from a metal oxide that has a density of less than or equal to 7.0 grams per cubic centimeter, while M2, M3, M4, . . . , MN each represent a different element derived from the plurality of metal oxides each of which have a density greater than 7.0 g/cm3;
• suspending the metal oxide in a solvent to form a suspension;
• disposing the suspension on an airfoil;
• and
• heating the suspension to dry the composition.