Formation of discontinuous Al2O3 layers during high-temperature oxidation of RuAl alloys

2006 ◽  
Vol 21 (1) ◽  
pp. 276-286 ◽  
Author(s):  
P.J. Bellina ◽  
A. Catanoiu ◽  
F.M. Morales ◽  
M. Rühle
Keyword(s):  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
Microstructural Characterization ◽  
Isothermal Oxidation ◽  
Thermal Barrier ◽  
Interface Instability ◽  
Temperature Oxidation ◽  
Bond Coats ◽  
Barrier Coating ◽  
Transmission Electron

Bond coats play a crucial role in the performance of thermal barrier coating systems. Ru alloys have been identified as promising candidates; therefore, systematic studies were performed on the oxidation behavior of bulk RuAl (50–50 at.%). Isothermal oxidation and thermogravimetric analyses were performed at 1100 °C for different times ranging from 0.1 h to 500 h. Microstructural characterization was performed by scanning and transmission electron microscopy. The results showed the formation of an α–Al2O3 layer on top of a δ–Ru layer. Interface instability between these layers and evaporation of gaseous Ru-oxides lead to the formation of large elongated cavities and alternating α–Al2O3/δ–Ru layers.

High Temperature Oxidation of Thermal Barrier Coating Systems on RR3000 Substrates: Pt Aluminide Bond Coats

2001 ◽  
Vol 369-372 ◽  
pp. 615-622 ◽  
Author(s):  
K. Bouhanek ◽  
O.A. Adesanya ◽  
F.Howard Stott ◽  
Peter Skeldon ◽  
D.G. Lees ◽  
...  
Keyword(s):  
High Temperature ◽  
Thermal Barrier Coating ◽  
High Temperature Oxidation ◽  
Thermal Barrier ◽  
Temperature Oxidation ◽  
Bond Coats ◽  
Barrier Coating

scholarly journals High Temperature Oxidation and Thermal Shock Properties of La2Zr2O7 Thermal Barrier Coatings Deposited on Nickel-Based Superalloy by Laser-Cladding

Coatings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 370 ◽  
Author(s):  
Kaijin Huang ◽  
Wei Li ◽  
Kai Pan ◽  
Xin Lin ◽  
Aihua Wang
Keyword(s):  
High Temperature ◽  
Thermal Shock ◽  
Laser Cladding ◽  
High Temperature Oxidation ◽  
Isothermal Oxidation ◽  
Oxidation Products ◽  
Thermal Barrier ◽  
Temperature Oxidation ◽  
Nickel Based Superalloy ◽  
Barrier Coating

In order to reduce the difficulty and cost of manufacturing and improve the high temperature oxidation and thermal shock properties of nickel-based superalloy, a thin La2Zr2O7 thermal barrier coating without bond coat was successfully prepared by laser-cladding using La2Zr2O7 powders on a nickel-based superalloy substrate. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) methods were used to characterize the microstructure of the coating. The high temperature oxidation and thermal shock properties of the coating were evaluated by the air isothermal oxidation method at 1100 °C for 110 h and thermal cycling method at 25~1100 °C, respectively. The results show that the coating is mainly composed of La2Zr2O7 phase. The oxidation weight gain rate of the coating is about two-thirds of that of the substrate, and the first crack thermal shock lifetime of the coating is about 1.67 times of that of the substrate. The oxidation products of the coating are mainly Fe2O3, Cr2O3, NiCr2O4, Nb2O5 and La2Zr2O7. The existence of La2Zr2O7 phase in the coating is the main reason for the improvement of its oxidation resistance at 1100 °C and its thermal shock resistance at 25~1100 °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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