Microtopographic inspection of laser-glazed thermal barrier coatings

Manuel Filipe M. Costa; C. Batista; A. Portinha; Vasco M. Teixeira; C. R. Oliveira; Ricardo Mendes Ribeiro

doi:10.1117/1.2946698

1 June 2008 Microtopographic inspection of laser-glazed thermal barrier coatings

Manuel Filipe M. Costa, C. Batista, A. Portinha, Vasco M. Teixeira, C. R. Oliveira, Ricardo Mendes Ribeiro

Author Affiliations +

Optical Engineering, Vol. 47, Issue 6, 063603 (June 2008). https://doi.org/10.1117/1.2946698

Abstract

Thermal barrier coatings (TBCs) are extremely useful in gas turbine engines. The quality of these coatings can be improved by subjecting their surface to laser glazing. A reduction in surface roughness, eliminating open porosity on the surface, and the generation of a controlled segmented crack network, can be achieved. TBCs consisting of atmospheric plasma sprayed (APS) ZrO₂-8%wtY₂O₃ are subjected to a CO₂ continuous wave laser glazing process to seal their surface porosity, generating an external dense layer. Different amounts of irradiation are applied to the specimens. The microtopograpic inspection of the samples reveal a significant decrease of the surface roughness after laser treatment. However, a network of surface cracks, dependent on the laser scanning speed and track overlapping, are noticed. The cracks have a tendency to be oriented in two perpendicular directions, one in the direction of the laser beam travel direction, the other perpendicular to it. Cracks parallel to the beam scanning direction are found to be at the overlapping zone, in the edge of the subsequent track.

©(2008) Society of Photo-Optical Instrumentation Engineers (SPIE)

Citation Download Citation

Manuel Filipe M. Costa, C. Batista, A. Portinha, Vasco M. Teixeira, C. R. Oliveira, and Ricardo Mendes Ribeiro "Microtopographic inspection of laser-glazed thermal barrier coatings," Optical Engineering 47(6), 063603 (1 June 2008). https://doi.org/10.1117/1.2946698

Published: 1 June 2008

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