The effect of coating thickness on the contact fatigue and wear of thermal barrier coatings (TBCs) are investigated in this study. The same bondcoat material thickness (250 μm) are used for each sample, which allows the effect of the coating thickness of the topcoat to be investigated. TBCs with different coating thicknesses (200, 400, and 600 μm) are prepared by changing processing parameters such as the feeding rate of the feedstock, spraying speed, and spraying distance during APS(air plasma spray) coating. The damage size on the surface are strongly affected by the coating thickness effect. Although the damage size from contact fatigue using a spherical indenter diminish at a TBC of 200 μm, a high wear resistance such as a low friction coefficient and little mass change are found at a TBC of 600 μm. These results indicate that the coating thickness strongly affects the mechanical behavior in TBCs during gas turbine operation.

Keywords: Gas turbine, Thermal barrier coating, Coating thickness, Contact fatigue, Wear