Journal ArticleDOI
Surface thermal cracking of thermal barrier coatings owing to stress relaxation: zirconia vs. mullite
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TLDR
The initiation of surface cracks in zirconia based multilayer thermal barrier coatings is related to stress relaxation which occurs at the top surface of the coating at high temperatures as mentioned in this paper.Abstract:
The initiation of surface cracks in zirconia based multilayer thermal barrier coatings is related to stress relaxation which occurs at the top surface of the coating at high temperatures. An analytical model is used to show that the compressive stresses decrease over time and become tensile upon cooling of the coating, thus resulting in cracks. Mullite, which exhibits significantly reduced stress relaxation behavior, is shown to remain in compression, thus preventing the initiation of surface cracks. This behavior is compared for the cases of equal heat flux and equal surface temperature conditions.read more
Citations
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Journal ArticleDOI
Ceramic materials for thermal barrier coatings
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Journal ArticleDOI
Higher-order theory for functionally graded materials
TL;DR: In this article, the authors present a generalization of the Cartesian coordinate-based higher-order theory for functionally graded materials developed by the authors during the past several years, which is based on volumetric averaging of various field quantities, together with imposition of boundary and interfacial conditions in an average sense between the subvolumes used to characterize the composite's functionally graded microstructure.
Journal ArticleDOI
Effects of residual stress on the performance of plasma sprayed functionally graded ZrO2/NiCoCrAlY coatings
Khiam Aik Khor,Y.W. Gu +1 more
TL;DR: In this paper, functional graded ZrO2/NiCoCrAlY coatings were produced by plasma spraying using pre-mixed and spheroidized powders as the feedstock.
Journal ArticleDOI
Thermal fracture behavior of metal/ceramic functionally graded materials
Akira Kawasaki,Ryuzo Watanabe +1 more
TL;DR: In this article, the thermal fracture behavior of metal/ceramic functionally graded materials (FGMs) was evaluated by a well controlled burner heating method using a H2/O2 combustion flame, which simulated real environment.
Journal ArticleDOI
Modeling of residual stresses in a plasma-sprayed zirconia/alumina functionally graded-thermal barrier coating
TL;DR: In this article, a numerical study using finite element analysis (FEA) was performed to investigate the effects of system architecture on the residual stresses developed in functionally graded-thermal barrier coatings (FG-TBCs) and in a typical duplex TBC comprising of NiCoCrAlY bondcoat and ZrO2 topcoat.
References
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Mullite and mullite ceramics
TL;DR: Crystal Chemistry of Mullite Phase Equilibria of Mica and Mica-Ceramics Industrial Use of the Mullite as mentioned in this paper, and its Industrial Use in Mining and Mining.
Journal ArticleDOI
Plastic Deformation of Fine‐Grained Alumina (Al2O3): I, Interface‐Controlled Diffusional Creep
TL;DR: In this paper, the deformation dynamics of fine-grained alumina polycrystals (grain size 1 to 15 μm) were studied and diffusional creep, basal slip, and unaccommodated grain-boundary sliding were investigated.
Journal ArticleDOI
Performance of thermal barrier coatings in high heat flux environments
TL;DR: In this article, thermal barrier coatings were exposed to the high temperature and high heat flux produced by a 30 kW plasma torch, and the results showed that the temperature drop across the thickness of the 0.038 cm ceramic layer was about 1100 C after 0.5 sec in the flame.
Journal ArticleDOI
Thermal barrier coating development for diesel engine aluminum pistons
TL;DR: In this paper, a finite element model is used to analyze thermal barrier coating systems, including the impact of material properties, coating thickness, residual stress and boundary conditions, and the primary cause of coating failure is low cycle fatigue resulting from localized yielding when the coating is hot and in compression.
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