Laser based ablation of gas turbine blade coating system

To enable turbine components to run through reparations with recoating up to five operating cycles, a high surface quality with low roughness and the lowest possible base material removal is essential. In particular, the use of blades with thermal barrier coatings in combination with adhesive coatings, an efficient decoating method for the coating system is needed. The conventional decoating method is harmful to the environment due to aggressive fluids and strong acids, therefore laser decoating is analyzed in the current study as an alternative method. In this regard, a Nd:YAG laser, a fiber laser and a pico laser with wavelengths around 1 µm are used in in combination with a suitable largescale ablation strategy. By means of SEM-EDS analysis, the atomic elements in the coating were examined in more detail. First ablation tests on real blade components with complex geometry including curvatures and cooling air holes show promising results.