A Statistical Assessment of the Damage State in Plasma-Sprayed Thermal Barrier Coating

2003 ◽  
Author(s):  
X. J. Wu ◽  
P. C. Patnaik ◽  
M. Liao ◽  
W. R. Chen
Keyword(s):  
Thermal Barrier Coating ◽  
Bond Coat ◽  
Damage Evolution ◽  
Protective Coatings ◽  
Mechanistic Model ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Damage State ◽  
Barrier Coating ◽  
Plasma Sprayed

Thermal barrier coatings (TBC), which consist of yttria-partially-stabilized zirconia top coat and metallic bond coat deposited onto superalloy substrate, are favorably used as protective coatings of the hot section parts in advanced gas turbine engines to withstand increased inlet temperatures and thus improve engine performance. However, understanding and modeling the damage evolution in TBC under service exposed conditions still remain to be a challenge. This is due to the failure by the coupled effects of the external load-environment, the thermal expansion mismatch between the bond coat and TBC, microstructure of the coating, and degradation of the bond coat. In this study, the damage state in an air-plasma-sprayed APS) thermal barrier coating system was assessed using metallurgical and statistical methods. The damage evolution in the TBC can thus be described with a high degree of confidence. A mechanistic model, representing the micro-cracking mechanism, is presented and its prediction is also assessed on a statistical basis.

scholarly journals Damage evolution in a self‐healing air plasma sprayed thermal barrier coating containing self‐shielding MoSi 2 particles

2019 ◽  
Vol 102 (8) ◽  
pp. 4899-4910 ◽  
Author(s):  
Ying Chen ◽  
Xun Zhang ◽  
Sybrand van der Zwaag ◽  
Willem G. Sloof ◽  
Ping Xiao
Keyword(s):  
Thermal Barrier Coating ◽  
Damage Evolution ◽  
Thermal Barrier ◽  
Self Healing ◽  
Air Plasma ◽  
Barrier Coating ◽  
Plasma Sprayed

scholarly journals Investigation on the performance of air plasma sprayed thermal barrier coating with Lu/Hf-doped NiAl bond coat

2019 ◽  
Vol 360 ◽  
pp. 140-152 ◽  
Author(s):  
Chunshan Zhao ◽  
Lirong Luo ◽  
Jie Lu ◽  
Xiaofeng Zhao ◽  
Xin Wang ◽  
...  
Keyword(s):  
Thermal Barrier Coating ◽  
Bond Coat ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Barrier Coating ◽  
Plasma Sprayed

Depletion Model of Aluminum in Bond Coat for Plasma-Sprayed Thermal Barrier Coatings

2009 ◽  
Vol 75 ◽  
pp. 31-35 ◽  
Author(s):  
Chang Che ◽  
G.Q. Wu ◽  
Hong Yu Qi ◽  
Z. Huang ◽  
Xiao Guang Yang
Keyword(s):  
Mathematical Model ◽  
Thermal Barrier Coating ◽  
Thermal Barrier Coatings ◽  
Bond Coat ◽  
Thermal Exposure ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Barrier Coatings ◽  
Barrier Coating ◽  
Plasma Sprayed

The aluminum depletion of NiCrAlY bond coat in an air-plasma-sprayed thermal barrier coating (TBC) has been studied by experimental and simulative approaches. Upon thermal exposure, Al depletion regions were observed. The depletion of aluminum is resulting from Al diffusion towards the surface of bond coat and into substrate. A mathematical model of Al depletion was presented. The model is able to explain the observed results in a qualitative way and has been shown that Al depletes within the bond coat by diffusion.

scholarly journals Thermal Fatigue Behavior of Air-Plasma Sprayed Thermal Barrier Coating with Bond Coat Species in Cyclic Thermal Exposure

Materials ◽  
2013 ◽  
Vol 6 (8) ◽  
pp. 3387-3403 ◽  
Author(s):  
Zhe Lu ◽  
Sang-Won Myoung ◽  
Yeon-Gil Jung ◽  
Govindasamy Balakrishnan ◽  
Jeongseung Lee ◽  
...  
Keyword(s):  
Thermal Barrier Coating ◽  
Thermal Fatigue ◽  
Bond Coat ◽  
Fatigue Behavior ◽  
Thermal Exposure ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Barrier Coating ◽  
Thermal Fatigue Behavior ◽  
Plasma Sprayed

scholarly journals Isothermal and Cyclic Oxidation of an Air Plasma-Sprayed Thermal Barrier Coating System

1996 ◽  
Author(s):  
J. Allen Haynes ◽  
Mattison K. Ferber ◽  
Wallace D. Porter ◽  
E. Douglas Rigney
Keyword(s):  
Thermal Barrier Coating ◽  
Oxidation Kinetics ◽  
Bond Coat ◽  
High Mass ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Reaction Products ◽  
Barrier Coating ◽  
Plasma Sprayed ◽  
Tbc Systems

Thermogravimetric methods for evaluating bond coat oxidation in plasma-sprayed thermal barrier coating (TBC) systems were assessed by high-temperature testing of TBC systems with air plasma-sprayed (APS) Ni-22Cr-10Al-1Y bond coatings and yttria-stabilized zirconia top coatings. High-mass thermogravimetric analysis (at 1150°C) was used to measure bond coat oxidation kinetics. Furnace cycling was used to evaluate APS TBC durability. This paper describes the experimental methods and relative oxidation kinetics of the various specimen types. Characterization of the APS TBCs and their reaction products are discussed.

scholarly journals Cracking Behaviour of an Air-Plasma-Sprayed Thermal Barrier Coating

2009 ◽  
Author(s):  
W. R. Chen ◽  
X. Wu ◽  
B. R. Marple ◽  
X. Huang ◽  
P. C. Patnaik
Keyword(s):  
Thermal Barrier Coating ◽  
Bond Coat ◽  
Thermally Grown Oxide ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Barrier Coating ◽  
Ceramic Bond ◽  
Maximum Crack ◽  
Plasma Sprayed ◽  
Thermally Sprayed

The degradation of a thermal barrier coating (TBC) system is dominated by the formation and growth of a thermally grown oxide (TGO) layer between the ceramic topcoat and metallic bond coat, leading to a separation near the ceramic/bond coat interface during service. Crack propagation in a thermally sprayed TBC normally proceeds via the opening and growth of pre-existing discontinuities in the ceramic layer near the ceramic/bond coat interface region assisted by cracking associated with the evolution of the TGO. The combined effect of these degradation processes results in premature TBC failure. In the present study, TGO growth and cracking behaviours were investigated under cyclic oxidation conditions with different cycle frequencies. The results showed a likely relationship between the maximum crack length and TGO thickness, suggesting that the establishment of an empirical formula may be possible to serve as the basis for a TBC life prediction model.

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').

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