scholarly journals Microstructural and mechanical properties of thermal barrier coating at 1400°C treatment

2014 ◽  
Vol 4 (2) ◽  
pp. 021008 ◽  
Author(s):  
Jianguo Zhu ◽  
Kang Ma
Keyword(s):  
Mechanical Properties ◽  
Thermal Barrier Coating ◽  
Thermal Barrier ◽  
Barrier Coating

scholarly journals Phase Composition, Thermal Conductivity, and Toughness of TiO2-Doped, Er2O3-Stabilized ZrO2 for Thermal Barrier Coating Applications

Coatings ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 253 ◽  
Author(s):  
Qi Wang ◽  
Lei Guo ◽  
Zheng Yan ◽  
Fuxing Ye
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Phase Composition ◽  
Thermal Barrier Coating ◽  
Thermal Barrier ◽  
Promising Candidate ◽  
Dopant Content ◽  
Barrier Coating ◽  
M Phase ◽  
T Phase

TiO2 was doped into Er2O3-stabilized ZrO2 (ErSZ) to obtain desirable properties for thermal barrier coating (TBC) applications. The phase composition, thermal conductivity, and mechanical properties of TiO2-doped ErSZ were investigated. ErSZ had a non-transformable metastable tetragonal (t′) phase, the compound with 5 mol % TiO2 consisted of t′ and cubic (c) phases, while 10 mol % TiO2 doped ErSZ had t′, c, and about 3.5 mol % monoclinic (m) phases. Higher TiO2 doping contents caused more m phase, and the compounds were composed of t′ and m phases. When the dopant content was below 10 mol %, TiO2 doping could decrease the thermal conductivity and enhance the toughness of the compounds. At higher doping levels, the compounds exhibited an increased thermal conductivity and a reduction in the toughness, mainly attribable to the formation of the undesirable m phase. Hence, 10 mol % TiO2-doped ErSZ could be a promising candidate for TBC applications.

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.

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