Nickel aluminide coating with improved oxide stability

A NiAl overlay bond coating composition comprising a NiAl alloy, the alloy comprising Zr and at least one modifying element in an amount effective to form a stabilized oxide structure comprising stabilized zirconia including a substantially tetragonal structure upon oxidation of the alloy, wherein the tetragonal structure is stabilized such that it does not change phases and revert to a monoclinic or monoclinic and tetragonal structure, which is not substantially tetragonal, upon thermal cycling wherein the element is an element selected from the group consisting of Mg in an amount effective to form between about 4 and about 12 mol. % MgO in the zirconia, which stabilizes the zirconia, Dy in an amount effective to form between about 4 and about 20 mol. % DyO1.5 in the zirconia, which stabilizes the zirconia, Eu in an amount effective to form between about 4 and about 13 mol. % EuO1.5 in the zirconia, which stabilizes the zirconia, Sc in an amount effective to form between about 4 and about 17 mol. % ScO1.5 in the zirconia, which stabilizes the zirconia, La in an amount effective to form between about 4 and about 20 mol. % LaO1.5 in the zirconia, which stabilizes the zirconia, Er in an amount effective to form between about 4 and about 20 mol. % ErO1.5 in the zirconia, which stabilizes the zirconia, Ce in an amount effective to form between about 10 and about 40 mol. % CeO2 in the zircoma, which stabilizes the zirconia, and Gd in an amount effective to form between about 4 and about 20 mol.% GdO1.5 in the zirconia.

A method of producing a stable, thermally grown oxide structure comprising:

• providing a NiAl overlay bond coat comprising a NiAl alloy, the NiAl alloy comprising Zr and at least one modifying element selected from the group consisting of Mg, Dy, Eu, Sc, La, Er, Gd, and Ce in an amount effective to form a stabilize oxide structure comprising zirconia having a substantially tetragonal structure upon oxidation of the alloy;
• and
• exposing the alloy to heat to thereby oxidize the alloy and form the stable, thermally grown oxide structure;
• wherein the tetragonal structure does not change phases and revert to a monoclinic or monoclinic and tetragonal structure, which is not substantially tetragonal, upon heating or thermal cycling.