A method for removing a chromide coating from the surface of a substrate is described.
The coating is treated with a composition which includes an acid having the formula
HxAF6, where "A" can be Si, Ge, Ti, Zr, Al, or Ga; and x
is 1-6. An exemplary acid is hexafluorosilicic acid. The composition may also include
a second acid, such as phosphoric acid or nitric acid. In some instances, a third
acid is employed, such as hydrochloric acid. A related repair method for replacing
a worn or damaged chromide coating is described. The coating is often applied to
portions of turbine engine components made from superalloy materials.