The effect of morphology of thermally grown oxide on the stress field in a turbine blade with thermal barrier coatings

2015 ◽  
Vol 276 ◽  
pp. 160-167 ◽  
Author(s):  
W. Zhu ◽  
M. Cai ◽  
L. Yang ◽  
J.W. Guo ◽  
Y.C. Zhou ◽  
...  
Keyword(s):  
Stress Field ◽  
Turbine Blade ◽  
Thermal Barrier Coatings ◽  
Thermally Grown Oxide ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Thermally Grown

Determination of the Structure and Chemistry of Thermally Grown Oxides in Thermal Barrier Coatings

1999 ◽  
Vol 5 (S2) ◽  
pp. 854-855
Author(s):  
M.R. Brickey ◽  
J.L. Lee
Keyword(s):  
Thermal Barrier Coatings ◽  
Nickel Aluminide ◽  
Physical Vapor Deposition ◽  
Thermal Exposure ◽  
Thermally Grown Oxide ◽  
Thermal Barrier ◽  
Engine Operation ◽  
Barrier Coatings ◽  
Combustion Gas ◽  
Thermally Grown

Thermal barrier coatings (TBCs) insulate gas turbine hot section components from the hot (∽1200 - 1450°C) combustion gas exhaust stream. An airline company can save millions of dollars per year by using TBCs to protect vital engine components and to improve fuel efficiency. TBCs typically consist of an 8 wt.% yttria-partially-stabilized zirconia (YPSZ) ceramic topcoat deposited on a platinum-nickel-aluminide (Pt-Ni-Al) bondcoat covering a nickel-based superalloy substrate. Thermal exposure during YPSZ electron beam-physical vapor deposition (EB-PVD) and engine operation promotes the formation of a thermally grown oxide (TGO) between the Pt-Ni-Al and the YPSZ layers. Stresses can develop at the Pt-Ni-Al/TGO and TGO/YPSZ interfaces due to TGO growth and thermal expansion coefficient mismatch. These stresses eventually cause spallation of the YPSZ, leaving the metallic substrate vulnerable to high temperature degradation since exhaust temperatures are often higher than the melting temperature of most nickel-based superalloys (∽1200 - 1450°C).

Interfacial Kinetics of High Temperature Oxidation in YSZ Thermal Barrier Coatings With Bond Coatings of NiCoCrAlY With 0.25% Hf

2009 ◽  
Author(s):  
Winston Soboyejo ◽  
Patrick Mensah ◽  
Ravinder Diwan
Keyword(s):  
High Temperature ◽  
Thermal Barrier Coatings ◽  
High Temperature Oxidation ◽  
Structural Evolution ◽  
Isothermal Oxidation ◽  
Thermally Grown Oxide ◽  
Thermal Barrier ◽  
Temperature Oxidation ◽  
Barrier Coatings ◽  
Thermally Grown

This paper presents the results of an experimental study of the high-temperature isothermal oxidation behavior and micro-structural evolution in plasma sprayed thermal barrier coatings (TBCs) at temperatures between 900 and 1200 °C. Two types of specimens were produced for testing. These include a standard and vertically cracked (VC) APS. High temperature oxidation has been carried out at 900, 1000, 1100 and 1200 °C. The experiments have been performed in air under isothermal conditions. At each temperature, the specimens are exposed for 25, 50, 75 and 100 hours. The corresponding microstructures and microchemistries of the TBC layers are then examined using scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy EDS. Changes in the dimensions of the thermally grown oxide (TGO) layer are determined as functions of time and temperature. The evolution of bond coat microstructures/interdiffusion zones and thermally grown oxide (TGO) layers are compared in TBCs with standard (STD) and vertically cracked (VC) microstructures.

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