Abstract
Thermal barrier coatings are gaining considerable importance for the improvement the energetic efficiency of turbines. These materials are often applied on the surface of blades and are based on a layer of antioxidation material (mainly MCrAlY alloys) and a top layer that acts as proper thermal barrier (normally Yttria partially stabilized Zirconia). Coating removal is an important aspect in the production of these blades. "Decoating" or "stripping" is needed for the production of new components as well as for the reconditioning of existing ones. The present paper is dedicated to the comparison of different stripping methods and to the characterization of the blades surface after removal of thermal spray coatings both of Zirconia and of MCrAlY. The results reported here show that chemical stripping is particularly suitable for MCrAlY coating removal and does not affect the substrate. Water jet stripping can successfully be used for Zirconia-MCrAlY system removal although care is needed to avoid substrate damage. Salt bath technologies have been formed to be effective for TBC removal but not for MCrAlY removal.
