Determination of local residual stress in an air plasma spray thermal barrier coating (APS-TBC) by microscale ring coring using a picosecond laser

2019 ◽  
Vol 167 ◽  
pp. 126-130 ◽  
Author(s):  
Xun Zhang ◽  
Chun Li ◽  
Philip J. Withers ◽  
Nicolaie Markocsan ◽  
Ping Xiao
Keyword(s):  
Residual Stress ◽  
Thermal Barrier Coating ◽  
Plasma Spray ◽  
Picosecond Laser ◽  
Thermal Barrier ◽  
Air Plasma Spray ◽  
Air Plasma ◽  
Barrier Coating

HOT CORROSION OF CERIA-YTTRIA STABILIZED ZIRCONIA PLASMA SPRAYED THERMAL BARRIER COATING BY EUTECTIC VANDIUM PENTAOXIDE-SODIUM SULFATE

2018 ◽  
Vol 18 (1) ◽  
pp. 182-192 ◽  
Author(s):  
Mohammed J Kadhim ◽  
Mohammed H Hafiz ◽  
Maryam A Ali Bash
Keyword(s):  
Thermal Barrier Coating ◽  
Hot Corrosion ◽  
Monoclinic Phase ◽  
Volume Fraction ◽  
High Volume ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Plan View ◽  
Barrier Coating ◽  
Plasma Sprayed

The high temperature corrosion behavior of thermal barrier coating (TBC) systemconsisting of IN-738 LC superalloy substrate, air plasma sprayed Ni24.5Cr6Al0.4Y (wt%)bond coat and air plasma sprayed ZrO2-20 wt% ceria-3.6 wt% yttria (CYSZ) ceramic coatwere characterized. The upper surfaces of CYSZ covered with 30 mg/cm2 , mixed 45 wt%Na2SO4-55 wt% V2O5 salt were exposed at different temperatures from 800 to 1000 oC andinteraction times from 1 up to 8 h. The upper surface plan view of the coatings wereidentified for topography, roughness, chemical composition, phases and reaction productsusing scanning electron microscopy, energy dispersive spectroscopy, talysurf, and X-raydiffraction. XRD analyses of the plasma sprayed coatings after hot corrosion confirmed thephase transformation of nontransformable tetragonal (t') into monoclinic phase, presence ofYVO4 and CeVO4 products. Analysis of the hot corrosion CYSZ coating confirmed theformation of high volume fraction of YVO4, with low volume fractions of CeOV4 and CeO2.The formation of these compounds were combined with formation of monoclinic phase (m)from transformation of nontransformable tetragonal phase (t').

Modeling Thermally Grown Oxides in Thermal Barrier Coatings Using Koch Fractal

2019 ◽  
Author(s):  
Peter Warren ◽  
Sandip Haldar ◽  
Seetha Raghavan ◽  
Ranajay Ghosh
Keyword(s):  
Thermal Barrier Coating ◽  
Critical Role ◽  
Thermally Grown Oxide ◽  
Stress Generation ◽  
Interfacial Region ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Barrier Coating ◽  
Koch Fractal ◽  
Thermally Grown

Abstract Growth of the Thermally Grown Oxide (TGO) between the bond coat and thermal barrier coating (TBC) during service is one of the most common causes of failure within thermal barrier coating (TBC) systems. Initially this oxide will provide protection from oxidation for the substrate, but stress build up will contribute to delamination of the topcoat. Research has been carried out over the stresses caused by this TGO growth, and how to best mitigate these induced stresses. The interface topography plays a critical role for air plasma sprayed (APS) TBCs in development of stress profiles across the TGO/TBC interface [1, 2]. The APS TBCs fail by cracking in the TBC close to the TGO-TBC interface. Most models treat TGO as a sinusoidal wavelength interface. However, most TGO surfaces have been experimentally observed to have fractal like patterns at the interfacial region of the bondcoat and topcoat. Fractals provide us a better understanding of interactions at rough interfaces between two materials adhered to one another. In this work, we model the topography of the TGO using a Koch fractal. We find the geometry selected to model the TGO layer has a direct effect on the stress generation and creep strain during simulation.

Pore filling behavior of air plasma spray thermal barrier coatings under CMAS attack

2020 ◽  
Vol 167 ◽  
pp. 108478
Author(s):  
Xiao Shan ◽  
Wenfu Chen ◽  
Lixia Yang ◽  
Fangwei Guo ◽  
Xiaofeng Zhao ◽  
...  
Keyword(s):  
Thermal Barrier Coatings ◽  
Plasma Spray ◽  
Thermal Barrier ◽  
Air Plasma Spray ◽  
Air Plasma ◽  
Pore Filling ◽  
Barrier Coatings
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