R. Vaßen, Forschungszentrum Jülich GmbH, Jülich, Germany; D. Stöver, Forschungszentrum Juelich, Juelich, Germany
Thermal barrier coatings (TBCs) with different types of microstructures were produced with the atmospheric plasma-spraying (APS) process. The investigation includes a variation of the micro crack density and of the porosity level. In addition, also segmented TBCs were produced. Finally, also PVD-TBC systems have added to the investigation.
The different TBC systems were cycled in a natural gas/oxygen burner rig with a surface temperature of about 1250°C and a bond coat temperature of about 1100°C or below. The used relatively low surface temperature guarantees a failure mode close to the bond coat promoted by the growth of the thermally grown oxide (TGO). After failure metallographic inspection was made to determine the thickness of the TGO layer and the depleted zone. In addition, the crack path was analyzed and compared for the different microstructures.
Summary: Thermal barrier coatings (TBCs) with different types of microstructures were produced with the atmospheric plasma-spraying (APS) process. The investigation includes a variation of the micro crack density and of the porosity level. In addition, also segmented TBCs were produced. Finally, also PVD-TBC systems have added to the investigation.
The different TBC systems were cycled in a natural gas/oxygen burner rig with a surface temperature of about 1250°C and a bond coat temperature of about 1100°C or below. The used relatively low surface temperature guarantees a failure mode close to the bond coat promoted by the growth of the thermally grown oxide (TGO). After failure metallographic inspection was made to determine the thickness of the TGO layer and the depleted zone. In addition, the crack path was analyzed and compared for the different microstructures.
