Abstract No.:
5202

 Scheduled at:
Wednesday, June 07, 2017, Hall 27 2:00 PM
Suspension Spraying I


 Title:
SPS coating microstructure controlled by the surface topography using laser texturing

 Authors:
Robin Kromer / University Franche-Comté , France
P. Sokolowski / Faculty of Mechanical Engineering, Wroclaw University of Science and Engineering, Poland
R.T. Candidato/ SPCTS, University of Limoges, France
S. Costil*/ University Bourgogne Franche-Comté, France
L. Pawlowski/ SPCTS, University of Limoges, France

 Abstract:
Thermal barrier coatings (TBCs) fabricated either by atmospheric plasma spraying (APS) or electron beam physical vapor deposition (EB PVD) are widely used in the hot-temperature sections of turbines to provide thermal and corrosion protections. An emerging technology of suspension plasma spraying has become interesting for the production of thermal barrier coatings thanks to the advantages of columnar structure similar to that of EB-PVD deposits associated with considerably lower price of manufacturing. A narrow window of optimal suspension plasma spraying parameters remain an outstanding problem in reaching a favorable microstructure. The recent studies demonstrated that the substrate roughness may play an important role in reaching columnar growth of the coatings. This study presents a follow up by showing how the substrate topography obtained by laser surface texturing may be controlled to create regular columnar structure thanks to. The laser generated peaks disposed regularly on the surface can promote columnar structure growth. The formulated suspensions were sprayed onto superalloy substrates coated with powder plasma sprayed bond coats. Optimized previously, plasma spray parameters were selected to generate columnar structures and to find out the influence of the suspension behavior on coating microstructures. Testing of the produced thermal barrier coating (TBC) systems has included thermal cyclic tests and oxidation analysis. The results indicate that columnar SPS coating microstructure can be controlled using laser tools. Test results suggest that control of surface topography may be an important factor to improve the performances of SPS coatings.

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