scholarly journals Effects of Layer Thickness and Edge Conditions to Thermoelastic Characteristics on Thermal Barrier Coatings

2014 ◽  
Vol 05 (16) ◽  
pp. 2417-2425
Author(s):  
Jaegwi Go ◽  
Je-Hyun Lee
Keyword(s):  
Layer Thickness ◽  
Thermal Barrier Coatings ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Edge Conditions ◽  
Thermoelastic Characteristics

Effects of Pre-Oxide Layer Thickness on Thermal Cyclic Behavior of Thermal Barrier Coatings

2007 ◽  
Vol 336-338 ◽  
pp. 1746-1749 ◽  
Author(s):  
Dong Bo Zhang ◽  
Sheng Kai Gong ◽  
Hui Bin Xu
Keyword(s):  
Oxide Layer ◽  
Layer Thickness ◽  
Thermal Barrier Coatings ◽  
Failure Modes ◽  
Thermally Grown Oxide ◽  
Layer Growth ◽  
Cyclic Behavior ◽  
Thermal Barrier ◽  
Oxide Layer Thickness ◽  
Barrier Coatings

Conventional two-layered structure thermal barrier coatings (TBCs) with different pre-oxide layer thicknesses were produced by EB-PVD onto Ni-based superalloy. The pre-oxide layer with different thicknesses was formed after vacuum heat treatment for 2 hours and before ceramic deposition by heating the bond coat to 1323K in air for different times. It has been found that with pre-oxide layer thickness increasing from 1μm to 3.1μm, the growth rate of thermally grown oxide (TGO) increased during thermal cycling test and the thermal cyclic lifetime of TBCs decreased from 730hs to 400hs Two failure modes were observed for TBCs with different pre-oxide layer thicknesses and different TGO layer growth rates.

scholarly journals Durability of Gadolinium Zirconate/YSZ Double-Layered Thermal Barrier Coatings under Different Thermal Cyclic Test Conditions

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2238
Author(s):  
Satyapal Mahade ◽  
Nicholas Curry ◽  
Stefan Björklund ◽  
Nicolaie Markocsan ◽  
Shrikant Joshi
Keyword(s):  
Layer Thickness ◽  
Thermal Barrier Coatings ◽  
Failure Modes ◽  
Cyclic Test ◽  
Sintering Behavior ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Gadolinium Zirconate ◽  
Test Conditions ◽  
Thermal Cyclic Test

Higher durability in thermal barrier coatings (TBCs) is constantly sought to enhance the service life of gas turbine engine components such as blades and vanes. In this study, three double layered gadolinium zirconate (GZ)-on-yttria stabilized zirconia (YSZ) TBC variants with varying individual layer thickness but identical total thickness produced by suspension plasma spray (SPS) process were evaluated. The objective was to investigate the role of YSZ layer thickness on the durability of GZ/YSZ double-layered TBCs under different thermal cyclic test conditions i.e., thermal cyclic fatigue (TCF) at 1100 °C and a burner rig test (BRT) at a surface temperature of 1400 °C, respectively. Microstructural characterization was performed using SEM (Scanning Electron Microscopy) and porosity content was measured using image analysis technique. Results reveal that the durability of double-layered TBCs decreased with YSZ thickness under both TCF and BRT test conditions. The TBCs were analyzed by SEM to investigate microstructural evolution as well as failure modes during TCF and BRT test conditions. It was observed that the failure modes varied with test conditions, with all the three double-layered TBC variants showing failure in the TGO (thermally grown oxide) during the TCF test and in the ceramic GZ top coat close to the GZ/YSZ interface during BRT. Furthermore, porosity analysis of the as-sprayed and TCF failed TBCs revealed differences in sintering behavior for GZ and YSZ. The findings from this work provide new insights into the mechanisms responsible for failure of SPS processed double-layered TBCs under different thermal cyclic test conditions.

Analysis of Residual Stress and Damage Durability with Thermal Fatigue Behavior in Thermal Barrier Coatings

2004 ◽  
Vol 821 ◽  
Author(s):  
Dong-Ho Park ◽  
Hyung-Jun Jang ◽  
Yeon-Gil Jung ◽  
Jung-Chel Chang ◽  
Ungyu Paik
Keyword(s):  
Mechanical Properties ◽  
Layer Thickness ◽  
Thermal Barrier Coatings ◽  
Thermal Fatigue ◽  
Coating Layer ◽  
Fatigue Tests ◽  
Holding Time ◽  
Thermal Barrier ◽  
Bonding Layer ◽  
Barrier Coatings

AbstractStatic thermal fatigue tests for thermal barrier coatings (TBCs) were conducted to observe effects of temperature and holding time on its mechanical properties, hardness and modulus, and damage durability. For which three TBCs samples with different thickness in bonding layer (0.08, 0.14, and 0.28 mm) were prepared using an air plasma spraying (APS) method. Temperature of 950 and 1100°C and holding time of 10 and 100 hr were selected for the thermal fatigue tests. The TBCs with thin bonding layer (0.08 mm) maintain sound condition for all the thermal fatigue tests, even showing an evidence of cracking at the interface between coating and bonding layers. However, the TBCs with intermediate (0.14 mm) and thick (0.28 mm) bonding layers show delamination at interface and fracture of coating layer after the thermal fatigue tests at 1100°C for 100 hr. Thermal growth oxide (TGO) layer is created at the interface between coating and bonding layers in all the TBCs after the thermal fatigue tests, and the TGO layer thickness is mainly affected by temperature. Modulus and hardness of coating layer are increased with an increase of temperature in the thermal fatigue tests, due to the re-sintering of coating layer during the thermal fatigue tests. Effects of bonding layer thickness and thermal fatigue condition on mechanical properties, residual stresses, damage durability of the TBCs are discussed extensively.

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