Influence of Zirconia Powder Fractional Composition on Microstructure and Properties of Thermal Barrier Coating Obtained by Thermal Spraying

2019 ◽  
Vol 945 ◽  
pp. 700-705
Author(s):  
V.Yu. Hristosova ◽  
O. S. Bondareva ◽  
Sergey V. Konovalov
Keyword(s):  
Thermal Barrier Coating ◽  
Fractional Composition ◽  
Average Pore Size ◽  
Thermal Spraying ◽  
Physical And Mechanical Properties ◽  
Ceramic Layer ◽  
Thermal Barrier ◽  
Zirconia Powder ◽  
Average Pore ◽  
Barrier Coating

Thermal spraying is one of the most promising methods for obtaining thermal barrier coatings for aerospace applications. Providing the necessary set of coating properties and their stable reproducibility are an actual task of the modern production. The purpose of this work was to determine the influence of the initial powders fractional composition on the structure and properties of the protective coating. The microstructure and the elemental composition features of the heat-resistant and ceramic layers of the thermal barrier coating are investigated. It is shown that the microstructure, porosity and microhardness of the coating ceramic layer depend on the ZrO2+8%Y2O3initial powder fractional composition. The porosity of the coating and the average pore size increase with increasing particle size of the powder. The maximum value of the ceramic layer microhardness is observed when using a powder fraction of 40-80 μm. The studies have found that microstructure and the necessary combination of coating physical and mechanical properties are achieved during the deposition of zirconia powder fractions 40-80 microns.

Evolution of Thermal Barrier Coating Strain Tolerance During Engine Operation and its Application to Lifing Models

2012 ◽  
Author(s):  
Markus Schaudinn ◽  
Grégoire Witz ◽  
Hans-Peter Bossmann
Keyword(s):  
Mechanical Properties ◽  
Thermal Barrier Coating ◽  
Residual Life ◽  
Propagation Model ◽  
Ceramic Layer ◽  
Limiting Factor ◽  
Thermal Barrier ◽  
Engine Operation ◽  
Strain Tolerance ◽  
Barrier Coating

Models for thermal barrier coating lifetime prediction are often based on bondcoat oxidation models leading to an end of life criterion either based on bondcoat full consumption or a critical thermally grown oxide thickness. Such models can be satisfactory on turbine parts where the most common coating delamination modes are black or grey failure which are linked to the bondcoat behaviour. Such models are not reliable for combustor parts with thick thermal barrier coating systems where the most common life limiting factor is the formation of cracks appearing in the ceramic layer few tens of microns above the bondcoat interface. This behaviour is linked to the TBC layer mechanical properties and should be described by a model taking into account the evolution of the TBC mechanical properties during engine operation, the mechanical loads in the ceramic layer and a crack propagation model in the TBC. A study of the strain tolerance of TBC from combustor parts after engine operation was performed by taking samples from combustor liners at various locations having different TBC surface temperature. The strain tolerance of TBC samples was measured by four-point bending and correlated with the TBC microstructure and various engine operation parameters. It was shown that the TBC microstructure has an influence on TBC strain tolerance, and that the evolution of the TBC strain tolerance during engine operation is linked to the TBC temperature as well as the operating hours. The data have been used to develop a predictive model of the evolution of the TBC strain tolerance during engine operation. This model allows optimization of parts reconditioning interval, and provides tools for determining the residual life of coated components.

Two-Dimensional Thermal Performance Analysis of a Semi-Transparent Spectral Zirconia Thermal Barrier Coating

2004 ◽  
Author(s):  
Nalini Uppu ◽  
Patrick F. Mensah ◽  
Ravinder Diwan
Keyword(s):  
Heat Transfer ◽  
Thermal Barrier Coating ◽  
Thermal Performance ◽  
Operating Temperature ◽  
Turbine Blades ◽  
The Other ◽  
Ceramic Layer ◽  
Thermal Barrier ◽  
Barrier Coating ◽  
Super Alloy

The performance of an aero engine can be increased in two ways: one by reducing the air requirement for the cooling of the turbine blades and secondly by increasing the turbine inlet temperature (TIT) that is operating temperature of the turbine blades. Taking into account the latter approach the blade material must withstand high temperatures of above 1350°C. For this enhancing purpose, protective coatings called the thermal barrier coatings (TBC) are being employed. The thermal barrier coating mainly consists of two layers; one is the metallic coating MCrAlY, which is the premiere layer over the substrate Ni based super alloy. The other is the ceramic layer made of Yttria Stabilized Zirconia (YSZ). Apart from these two layers, an intermediate layer of Al2O3 is formed by the oxidation of the aluminum in MCrAlY called the diffusion layer which also enhances the adhesion between the two layers. M stands for Nickel or Cobalt. The present study is an investigation on the in-situ thermal performance of TBCs by considering the ceramic layer as a semi-transparent media and varying its thickness and simultaneously increasing the operating temperature on its other boundary surface. The above thermal boundary value problem is modeled in 2-dimensions and solved numerically using the discrete ordinate model for radiative heat transfer in a commercial computational fluid dynamics and heat transfer software. Two samples of Ni based super alloy substrate with dimensions 40 × 100 × 3mm are considered; one sample with a thickness of 0.25 mm ceramic layer and the other sample with 1 mm coating thickness for transient thermal analysis. Simulated transient temperature histories are presented for use in a thermo-mechanical analysis in order to predict the failure modes in the TBC. The temperature distribution in TBC coating mainly depends on the radiative effects combined with heat conduction and convection and radiation at the material boundaries.

Mechanisms of Degradation and Failure in a Plasma-Deposited Thermal Barrier Coating

1990 ◽  
Vol 112 (4) ◽  
pp. 521-526 ◽  
Author(s):  
J. T. DeMasi-Marcin ◽  
K. D. Sheffler ◽  
S. Bose
Keyword(s):  
Thermal Barrier Coating ◽  
Damage Accumulation ◽  
Ceramic Coating ◽  
Coating Layer ◽  
Thermal Exposure ◽  
Ceramic Layer ◽  
Constitutive Behavior ◽  
Thermal Barrier ◽  
Accumulation Process ◽  
Barrier Coating

Failure of a two-layer plasma-deposited thermal barrier coating is caused by cyclic thermal exposure and occurs by spallation of the outer ceramic layer. Spallation life is quantitatively predictable, based on the severity of cyclic thermal exposure. This paper describes and attempts to explain unusual constitutive behavior observed in the insulative ceramic coating layer, and presents details of the ceramic cracking damage accumulation process, which is responsible for spallation failure. Comments also are offered to rationalize the previously documented influence of interfacial oxidation on ceramic damage accumulation and spallation life.

Thermal cycling and hot corrosion behavior of a novel LaPO4/YSZ double-ceramic-layer thermal barrier coating

2018 ◽  
Vol 44 (8) ◽  
pp. 8818-8826 ◽  
Author(s):  
Chenglong Zhang ◽  
Jingming Fei ◽  
Lei Guo ◽  
Jianxing Yu ◽  
Binbin Zhang ◽  
...  
Keyword(s):  
Thermal Cycling ◽  
Thermal Barrier Coating ◽  
Corrosion Behavior ◽  
Hot Corrosion ◽  
Ceramic Layer ◽  
Thermal Barrier ◽  
Barrier Coating

Superposed structure of double-ceramic layer based on YSZ/LaMgAl11O19 thermal barrier coating

2022 ◽  
Author(s):  
Binglin Zou ◽  
Xiaolong Cai ◽  
Yongqiu Zhang ◽  
Pai Huang ◽  
Ying Wang ◽  
...  
Keyword(s):  
Thermal Barrier Coating ◽  
Ceramic Layer ◽  
Thermal Barrier ◽  
Barrier Coating
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