The Influence of Post Treatment on Microstructure Characterization of Thermally Sprayed Abradable Coatings

To increase efficiency of the gas turbine it is desirable to minimize clearence between rotor and stator and gas leakage over the blade tips. To achieve this aim thermally sprayed abradable coatings are applied. The coating is soft enough to allow the blade tips to cut a path into the abradable layer at the same time this coating saves structural integrity and resists erosion from the gas stream.

In this study abradable composite coatings for service temperature of GTE under 870K (compressor) and above 1020K (turbine) were investigated. They were obtained by plasma spraying technology. The composition and microstructure of these coatings were investigated by using optical microscopy, EDS, SEM.

To achieve high abradability and at the same time high erosion resistance we changed post treatment parameters to control porosity and macrohardness. Microstructure сharacterization and erosion resistance of standard and new abradable composite coatings were studied compared to commercially available abradable materials. Results of test will be usefull to understand abradabillity of new abradable composite coatings.