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.

Sintering-induced delamination of thermal barrier coatings by gradient thermal cyclic test

2017 ◽  
Vol 100 (5) ◽  
pp. 1820-1830 ◽  
Author(s):  
Bo Cheng ◽  
Yu-Ming Zhang ◽  
Ning Yang ◽  
Meng Zhang ◽  
Lin Chen ◽  
...  
Keyword(s):  
Thermal Barrier Coatings ◽  
Cyclic Test ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Thermal Cyclic Test

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.

Influence of microstructure on the durability of gadolinium zirconate thermal barrier coatings using APS & SPPS processes

2018 ◽  
Vol 337 ◽  
pp. 117-125 ◽  
Author(s):  
Rishi Kumar ◽  
Drew Cietek ◽  
Chen Jiang ◽  
Jeffrey Roth ◽  
Maurice Gell ◽  
...  
Keyword(s):  
Thermal Barrier Coatings ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Gadolinium Zirconate

Performance of single YSZ, Gd2Zr2O7 and double-layered YSZ/Gd2Zr2O7 thermal barrier coatings in isothermal oxidation test conditions

Vacuum ◽  
2020 ◽  
Vol 177 ◽  
pp. 109401
Author(s):  
Kadir Mert Doleker ◽  
Abdullah Cahit Karaoglanli ◽  
Yasin Ozgurluk ◽  
Akira Kobayashi
Keyword(s):  
Thermal Barrier Coatings ◽  
Isothermal Oxidation ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Oxidation Test ◽  
Test Conditions

scholarly journals High-Porosity Thermal Barrier Coatings from High-Power Plasma Spray Equipment—Processing, Performance and Economics

Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 957
Author(s):  
Nicholas Curry ◽  
Matthias Leitner ◽  
Karl Körner
Keyword(s):  
Thermal Barrier Coatings ◽  
High Power ◽  
Deposition Efficiency ◽  
Sintering Behavior ◽  
Thermal Barrier ◽  
Low Density ◽  
High Porosity ◽  
Plasma System ◽  
Barrier Coatings ◽  
The Impact

High-porosity thermal barrier coatings are utilized on gas turbine components where maximizing the coating thermal insulation capability is the primary design criteria. Though such coatings have been in industrial use for some time, manufacturing high-porosity coatings quickly and efficiently has proven challenging. With the industry demand to increase productivity and reduce waste generation, there is a drive to look at improved coating manufacturing methods. This article looks at high-porosity coatings manufactured using a high-power plasma system in comparison with a current industrial coating. A commercial spray powder is compared with an experimental Low-Density powder developed to maximize coating porosity without sacrificing coating deposition efficiency. The resultant coatings have been assessed for their microstructure, adhesion strength, furnace cyclic lifetime, thermal conductivity and sintering behavior. Finally, the impact of spray processing on coating economics is discussed. The use of a Low-Density powder with a high-power plasma system allows a high-porosity coating to be manufactured more efficiently and more cost effectively than with conventional powder feedstock. The improvement in thermal properties for the experimental coating demonstrates there is scope to improve industrial coatings by designing with specific thermal resistance rather than thickness and porosity as coating requirements.

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