Processing and Thermal Cycling Effects on the Erosion Behavior of Thermal Barrier Coatings

1997 ◽  
Author(s):  
J. Gutleber ◽  
S. Sampath ◽  
S. Usmani
Keyword(s):  
Thermal Spray ◽  
Thermal Barrier Coatings ◽  
Room Temperature ◽  
Erosion Resistance ◽  
Thermal Spray Coatings ◽  
Thermal Barrier ◽  
Powder Particle Size ◽  
Barrier Coatings ◽  
Erosion Behavior ◽  
Spray Coatings

Abstract The erosion behavior of yttria stabilized zirconia thermal barrier coatings is investigated with respect to powder particle size. Solid particle erosion experiments were conducted at room temperature to determine the mechanism of erosion for ceramic thermal spray coatings. Testing was carried out on as-sprayed as well as thermally cycled specimens. Porosity and bend testing measurements indicate that a decrease in porosity and an increase in inter-lamellar strength leads to an increase in the erosion resistance of ceramic thermal spray coatings.

Erosion Behavior of PS-PVD Thermal Barrier Coatings and the Effect of Composite Coating (PS-PVD + APS) Thickness

2020 ◽  
Vol 993 ◽  
pp. 1095-1103
Author(s):  
Wen Long Chen ◽  
Hong Jian Wu ◽  
Min Liu ◽  
Xiao Ling Xiao
Keyword(s):  
Thermal Barrier Coatings ◽  
Erosion Resistance ◽  
Failure Behavior ◽  
Thermal Barrier ◽  
Dense Layer ◽  
Particle Erosion ◽  
Barrier Coatings ◽  
Erosion Behavior ◽  
Layered Coating ◽  
Resistance Performance

In this work, feather-column 7YSZ thermal barrier coatings (TBCs) were prepared by plasma spray-physical vapor deposition (PS-PVD). The anti-particle erosion test was carried out at room temperature to study the erosion behavior and failure mechanism of PS-PVD TBCs. The results showed that the particle erosion process of the PS-PVD TBCs experienced three stages of high-rate, medium-rate and slow-rate erosion. In order to improve the particle erosion resistance of the PS-PVD TBCs, different thicknesses of dense-layered coatings were prepared on the surface of the PS-PVD TBCs by air plasma spraying (APS). The effect of dense-layered thickness on the erosion behaviour of PS-PVD TBCs was discussed. Experimental results showed that, as the thickness of the dense-layered increased, the erosion resistance of the PS-PVD TBCs enhanced. When the thickness of the dense-layered coating was 5μm, it was not obvious upon the influence on the erosion failure behavior of the PS-PVD TBCs. In the case of a 10μm dense-layered coating, the erosion resistance performance of the PS-PVD TBCs improved by about 30%. While the erosion resistance performance of the PS-PVD TBCs increased almost 4 times when the thickness of the dense layer reached 20μm.

Thermal Cycling Behavior of Lanthanum-Cerium Oxide Thermal Barrier Coatings Prepared by Air Plasma Spraying

2007 ◽  
Vol 336-338 ◽  
pp. 1759-1761 ◽  
Author(s):  
Wen Ma ◽  
Yue Ma ◽  
Sheng Kai Gong ◽  
Hui Bin Xu ◽  
Xue Qiang Cao
Keyword(s):  
Cerium Oxide ◽  
Plasma Spraying ◽  
Thermal Barrier Coatings ◽  
Bond Coat ◽  
Room Temperature ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Air Plasma Spraying ◽  
Cyclic Testing ◽  
Barrier Coatings

Lanthanum-cerium oxide (La2Ce2O7, LC) is considered as a new candidate material for thermal barrier coatings (TBCs) because of its low thermal conductivity and high phase stability between room temperature and 1673K. The LC coatings with different La2O3 contents were prepared by air plasma spraying (APS) and their lifetime was evaluated by thermal cyclic testing from room temperature to 1373 K. The structures of the coatings were characterized by XRD and SEM and the deviation of the composition from the powder was determined by EDS analysis. Long time annealing for the freestanding coating at 1673K reveals that the near stoichiometric LC coating is stable up to 240h, and the stability decreases with increasing the deviation from stoichiometric LC composition. During thermal cyclic testing, spallation was observed within the top coat near the bond coat. It is considered that the effect of intrinsic stress caused by the coefficient of thermal expansion (CTE) mismatch between top coat and bond coat is larger than that of thermally grown oxide (TGO) and the bond adherence of top coat with TGO.

Mechanical Properties of Thermal Barrier Coatings at Room Temperature

2005 ◽  
Vol 290 ◽  
pp. 336-339 ◽  
Author(s):  
G. Guidoni ◽  
Y. Torres Hernández ◽  
Marc Anglada
Keyword(s):  
Mechanical Properties ◽  
Thermal Barrier Coatings ◽  
Room Temperature ◽  
Inconel 625 ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Bending Tests ◽  
Four Point Bending ◽  
Barrier Coating ◽  
Plasma Sprayed

Four point bending tests have been carried out on a thermal barrier coating (TBC) system, at room temperature. The TBC system consisted of a plasma sprayed Y-TZP top coat with 8 % in weight of Yttria, a bond coat of NiCrAlY and a Ni-based superalloy Inconel 625 as substrate. The TBC coating was deposited on both sides of the prismatic specimens. Efforts have been done in detecting the damage of the coating by means of Maltzbender et al [1] model.

Synchrotron XRD Measurements Mapping Internal Strains of Thermal Barrier Coatings During Thermal Gradient Mechanical Fatigue Loading

2014 ◽  
Author(s):  
Kevin Knipe ◽  
Albert C. Manero ◽  
Stephen Sofronsky ◽  
John Okasinski ◽  
Jonathan Almer ◽  
...  
Keyword(s):  
High Temperature ◽  
Thermal Barrier Coatings ◽  
Mechanical Loading ◽  
Bond Coat ◽  
Thermal Gradient ◽  
Room Temperature ◽  
Material Behavior ◽  
Thermal Barrier ◽  
X Rays ◽  
Barrier Coatings

An understanding of the high temperature mechanics experienced in Thermal Barrier Coatings (TBC) during cycling conditions would be highly beneficial to extending the lifespan of the coatings. This study will present results obtained using synchrotron x-rays to measure depth resolved strains in the various layers of TBCs under thermal mechanical loading and a superposed thermal gradient. Tubular specimens, coated with Yttria Stabilized Zirconia (YSZ) and an aluminum containing nickel alloy as a bond coat both through Electron Beam - Physical Vapor Deposition (EBPVD), were subjected to external heating and controlled internal cooling generating a thermal gradient across the specimen’s wall. Temperatures at the external surface were in excess of 1000 °C. Throughout high temperature testing, 2-D high-resolution XRD strain measurements are taken at various locations through the entire depth of the coating layers. Across the YSZ a strain gradient was observed showing higher compressive strain at the interface to the bond coat than towards the surface. This behavior can be attributed to the specific microstructure of the EB-PVD-coating, which reveals higher porosity at the outer surface than at the interface to the bond coat, resulting in a lower in plane modulus near the surface. This location at the interface displays the most significant variation due to applied load at room temperature with this effect diminishing at elevated uniform temperatures. During thermal cycling with a thermal gradient and mechanical loading, the bond coat strain moves from a highly tensile state at room temperature to an initially compressive state at high temperature before relaxing to zero during the high temperature hold. The results of these experiments give insight into previously unseen material behavior at high temperature which can be used to develop an increased understanding of various failure modes and their causes.

Ultra-Low Thermal Conductivity in Nanoscale Layered Oxides

2009 ◽  
Vol 132 (3) ◽  
Author(s):  
J. Alvarez-Quintana ◽  
Ll. Peralba-Garcia ◽  
J. L. Lábár ◽  
J. Rodríguez-Viejo
Keyword(s):  
Thermal Conductivity ◽  
Thermal Barrier Coatings ◽  
Room Temperature ◽  
Thermal Barrier ◽  
Layered Oxides ◽  
Barrier Coatings ◽  
3Ω Method ◽  
Nanometer Thickness ◽  
Intrinsic Thermal Conductivity ◽  
Strong Barrier

The cross-plane thermal conductivity of several nanoscale layered oxides SiO2/Y2O3, SiO2/Cr2O3, and SiO2/Al2O3, synthesized by e-beam evaporation was measured in the range from 30 K to 300 K by the 3ω method. Thermal conductivity attains values around 0.5 W/m K at room temperature in multilayer samples, formed by 20 bilayers of 10 nm SiO2/10 nm Y2O3, and as low as 0.16 W/m K for a single bilayer. The reduction in thermal conductivity is related to the high interface density, which produces a strong barrier to heat transfer rather than to the changes of the intrinsic thermal conductivity due to the nanometer thickness of the layers. We show that the influence of the first few interfaces on the overall thermal resistance is higher than the subsequent ones. Annealing the multilayered samples to 1100°C slightly increases the thermal conductivity due to changes in the microstructure. These results suggest a route to obtain suitable thermal barrier coatings for high temperature applications.

The Structure Property Relationship of Erosion Resistant Thermal Spray Coatings

1998 ◽  
Author(s):  
R.C. Tucker ◽  
A.A. Ashari
Keyword(s):  
Thermal Spray ◽  
Elevated Temperatures ◽  
Erosion Resistance ◽  
Industrial Applications ◽  
Thermal Spray Coatings ◽  
Steam Turbines ◽  
Structure Property ◽  
Spray Coatings ◽  
Relationship Of ◽  
The Relationship

Abstract Thermal spray coatings are widely used for erosion resistance, but the relationship between the microstructure of the coatings and their erosion resistance is not well understood. In this paper the performance of several commonly used coatings at ambient and elevated temperatures is reviewed in light of the coatings' structure and compared with a new coating. Two high temperature industrial applications, solid particle erosion in steam turbines and alumina-based erosion have been chosen to illustrate the significance of a coating's structure on its performance.

Solid particle erosion of thermal spray and physical vapour deposition thermal barrier coatings

Wear ◽  
2011 ◽  
Vol 271 (11-12) ◽  
pp. 2909-2918 ◽  
Author(s):  
F. Cernuschi ◽  
L. Lorenzoni ◽  
S. Capelli ◽  
C. Guardamagna ◽  
M. Karger ◽  
...  
Keyword(s):  
Thermal Spray ◽  
Solid Particle ◽  
Thermal Barrier Coatings ◽  
Vapour Deposition ◽  
Thermal Barrier ◽  
Solid Particle Erosion ◽  
Physical Vapour Deposition ◽  
Particle Erosion ◽  
Barrier Coatings
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