Development and Performance Evaluation of Thick Air Plasma Sprayed Thermal Barrier Coatings

2000 ◽  
Author(s):  
Z.Z. Mutasim ◽  
Y.L. Nava
Keyword(s):  
Thermal Barrier Coating ◽  
Thermal Barrier Coatings ◽  
Ceramic Coatings ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Barrier Coatings ◽  
Barrier Coating ◽  
And Performance ◽  
Plasma Sprayed ◽  
Industrial Gas Turbine

Abstract Air plasma sprayed thermal barrier coatings have been widely used to reduce metal wall temperatures of industrial gas turbine combustor liners. Thermal barrier coatings provide thermal gradients, with the goal of reducing the liner wall temperature to acceptable levels as a result of their low thermal conductivity. A typical thermal barrier coating consists of a 0.1-0.2 mm MCrAlY bond coating and a 0.25-0.35 mm thick 8 wt.% yttria stabilized zirconia ceramic top coating. A method to increase thermal barrier coating effectiveness is the application of thicker ceramic coatings. Development and performance testing of 0.5-0.8 mm thick ceramic coatings are discussed in this paper. Cyclic oxidation tests that simulate industrial gas turbine environments were conducted. Thermal barrier coating degradation-mechanisms were determined from microstructural evaluation of thermally exposed samples.

Characterization of Plasma Sprayed and Electron Beam-Physical Vapor Deposited Thermal Barrier Coatings

1997 ◽  
Author(s):  
Z. Mutasim ◽  
C. Rimlinger ◽  
W. Brentnall
Keyword(s):  
Electron Beam ◽  
Thermal Barrier Coatings ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Barrier Coatings ◽  
And Performance ◽  
Plasma Sprayed ◽  
Industrial Gas Turbine ◽  
Tbc Systems

Laboratory testing was conducted on air plasma sprayed (APS) and electron beam-physical vapor deposited (EB-PVD) thermal barrier coatings (TBCs) applied onto nickel alloy specimens. As-coated chemistry, microstructure, and bond strength of the TBC systems were evaluated. Cyclic oxidation tests that simulated industrial gas turbine environments were also conducted on the various thermal barrier coatings. This study evaluated the effects of ceramic and metallic coating compositions and application processes on coatings microstructure and performance. The relative cyclic performance of the TBC systems was determined from the laboratory tests.

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.

Effect of Spinel Growth on the Delamination of Thermal Barrier Coatings

2011 ◽  
Vol 462-463 ◽  
pp. 389-394 ◽  
Author(s):  
Wei Xu Zhang ◽  
Yong Le Sun ◽  
Tie Jun Wang
Keyword(s):  
Growth Rate ◽  
Service Life ◽  
Thermal Barrier Coating ◽  
Thermal Barrier Coatings ◽  
Unit Area ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Barrier Coating ◽  
Thermal Growth ◽  
Plasma Sprayed

The spinel growth induces undulation of the thermal growth oxide layer and decreases the service life of plasma-sprayed thermal barrier coatings. An analytical model is introduced to investigate the effect of spinel growth on the delamination of thermal barrier coating. The analytical results show that the number per unit area and the growth rate of spinel have significant influence on the delamination of thermal barrier coating. The stiffer and thicker thermal barrier coating is more easily to delaminate from the bond coat due to the existence of spinels. The effect of spinel on the delamination cannot be neglected. How to reduce the growth rate and the number of spinel is a key problem to prolong the service life of thermal barrier coatings.

A study of suspension plasma-sprayed insulated pistons evaluated in a heavy-duty diesel engine

2019 ◽  
Vol 21 (6) ◽  
pp. 987-997 ◽  
Author(s):  
Anders Thibblin ◽  
Ulf Olofsson
Keyword(s):  
Fuel Consumption ◽  
Thermal Barrier Coating ◽  
Thermal Barrier Coatings ◽  
Heat Losses ◽  
Specific Fuel Consumption ◽  
Atmospheric Plasma ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Barrier Coating ◽  
Plasma Sprayed

Thermal barrier coatings can be used to reduce the heat losses in heavy-duty diesel engines. A relatively new coating method for thermal barrier coatings is suspension plasma-spraying. Single-cylinder engine tests have been run to evaluate how heat losses to piston, cylinder head and exhausts as well as the specific fuel consumption are influenced by coating pistons with two different suspension plasma-sprayed thermal barrier coatings and one atmospheric plasma-sprayed thermal barrier coating, and comparing the results to those from an uncoated steel piston. The two suspension plasma-sprayed thermal barrier coatings showed reduced heat losses through the piston and less heat redirected to the cylinder head compared to conventional atmospheric plasma-sprayed thermal barrier coating, while one suspension plasma-sprayed coating with yttria-stabilized zirconia as top coat material showed increased exhaust temperature. However, the indicated specific fuel consumption was higher for all tested thermal barrier coatings than for an uncoated engine. The best performing thermal barrier coating with respect to indicated specific fuel consumption was a suspension plasma-sprayed coating with gadolinium zirconate as top coat material.

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').

scholarly journals An image-based model for the sintering of air plasma sprayed thermal barrier coatings

2021 ◽  
Vol 206 ◽  
pp. 116649
Author(s):  
Xun Zhang ◽  
Alan C.F. Cocks ◽  
Yoshifumi Okajima ◽  
Kazuma Takeno ◽  
Taiji Torigoe
Keyword(s):  
Thermal Barrier Coatings ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Barrier Coatings ◽  
Plasma Sprayed

NONDESTRUCTIVE IMPEDANCE SPECTROSCOPY EVALUATION OF THE BOND COAT OXIDATION IN THERMAL BARRIER COATINGS

2007 ◽  
Vol 14 (05) ◽  
pp. 935-943 ◽  
Author(s):  
L. YANG ◽  
Y. C. ZHOU ◽  
W. G. MAO ◽  
Q. X. LIU
Keyword(s):  
Impedance Spectroscopy ◽  
Thermal Barrier Coatings ◽  
Bond Coat ◽  
Equivalent Circuit Model ◽  
Isothermal Oxidation ◽  
Thermally Grown Oxide ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Barrier Coatings ◽  
Plasma Sprayed

In this paper, the impedance spectroscopy technique was employed to examine nondestructively the isothermal oxidation of air plasma sprayed (APS) thermal barrier coatings (TBCs) in air at 800°C. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were also used to characterize the microstructure evolution of TBCs. After oxidation, the thermally grown oxide (TGO), which was mainly composed of alumina as confirmed by EDX, formed at the upper ceramic coat/bond coat interface, the lower bond coat/substrate interface, and the bond coat. Impedance diagrams obtained from impedance measurements at room temperature were analyzed according to the equivalent circuit model proposed for the TBCs. Various observed electrical responses relating to the growth of oxides and the sintering of YSZ were explained by simulating the impedance spectra of the TBCs.

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