Abstract ▼ AI-Helper

The microstructural evolution related to the thickness of thermal barrier coating (TBC) and their thermal stability have been investigated with a specific attention to defect species as well as to its morphology with the thermal exposure time. The TBCs with different thicknesses of 600 and 2,000 &mi...

The microstructural evolution related to the thickness of thermal barrier coating (TBC) and their thermal stability have been investigated with a specific attention to defect species as well as to its morphology with the thermal exposure time. The TBCs with different thicknesses of 600 and 2,000 µm were prepared by an air plasma spray (APS) and the thermal exposure tests were performed at 950C in a furnace with a dwell time of 100 h till 500 h. The thickness of thermally grown oxide (TGO) layer in the TBC with 2,000 mm is thinner than that with 600 mm. Also, the TBC with 2,000 mm is more efficient in improving the oxidation resistance of bond coat than that with 600 mm. The crack formation of the TBC with 600 mm is easier than that with 2,000 mm, showing relatively longer cracks, independent of thermal exposure. However, the crack formation and propagation through the interface does not observed in the TBC with 2,000 mm, showing crack propagation through the top coat near the interface. These results imply that the interfacial stability of TBC can be also improved with increasing the coating thickness.
Keywords: Thermal barrier coatings; Thermal exposure; Thermally grown oxide; Oxidation resistance; Interfacial stability