A process for coating a gas turbine engine component is disclosed herein. The process comprises applying a bond coat on a substrate of a gas turbine engine. A thermal barrier material is applied to the bond coat. A coating containing polynuclear aluminum oxide/hydroxide clusters is then applied to the thermal barrier material. The polynuclear aluminum oxide/hydroxide clusters are Al13 Keggin clusters having the formula [AlO4Al12(OH)24(H2O)12]7+, or are salts of the Al13 Keggin clusters called Al13 Keggin complexes. A gas turbine engine component comprising a superalloy substrate; a bond coat disposed on the substrate; a thermal barrier material on the bond coat; and a coating containing the polynuclear aluminum oxide/hydroxide clusters on the thermal barrier material is disclosed herein.