First Principles and Multi-Scale Modeling of the Roles of Impurities and Dopants on Thermal Barrier Coating Failure

2007 ◽  
Author(s):  
Emily A. Carter
Keyword(s):  
Thermal Barrier Coating ◽  
First Principles ◽  
Thermal Barrier ◽  
Multi Scale ◽  
Scale Modeling ◽  
Barrier Coating ◽  
Coating Failure ◽  
Multi Scale Modeling

Multi-scale modeling of damage development in a thermal barrier coating

2015 ◽  
Vol 276 ◽  
pp. 399-407 ◽  
Author(s):  
L. Saucedo-Mora ◽  
K. Slámečka ◽  
U. Thandavamoorthy ◽  
T.J. Marrow
Keyword(s):  
Thermal Barrier Coating ◽  
Thermal Barrier ◽  
Damage Development ◽  
Multi Scale ◽  
Scale Modeling ◽  
Barrier Coating ◽  
Multi Scale Modeling

Multiscale modeling of charge transfer in polymers with flexible backbones

2019 ◽  
Vol 21 (4) ◽  
pp. 1812-1819 ◽  
Author(s):  
Masahiro Sato ◽  
Akiko Kumada ◽  
Kunihiko Hidaka
Keyword(s):  
First Principles ◽  
Kinetic Monte Carlo ◽  
First Principles Calculations ◽  
Multi Scale ◽  
Carrier Transfer ◽  
Scale Modeling ◽  
Kinetic Monte Carlo Simulations ◽  
Multi Scale Modeling ◽  
Dynamics Simulations ◽  
Transfer Properties

In order to evaluate carrier transfer properties in polymers with flexible backbones, we have proposed a simplified multi-scale modeling approach combining molecular dynamics simulations, first-principles calculations and kinetic Monte Carlo simulations.

Burner Rig Testing of Thermal Barrier Coatings for Lifetime Prediction

2014 ◽  
Author(s):  
Grégoire Witz ◽  
Klaus F. Staerk ◽  
Carlo M. Maggi ◽  
Ulrich Krasselt ◽  
Hans-Peter Bossmann
Keyword(s):  
Failure Mechanism ◽  
Thermal Barrier Coating ◽  
Thermal Gradient ◽  
Field Experience ◽  
Lifetime Prediction ◽  
Cyclic Test ◽  
Thermal Barrier ◽  
Test Results ◽  
Barrier Coating ◽  
Coating Failure

Thermal barrier coating lifetime prediction has been commonly performed using furnace cyclic test results. This testing method causes coating failures driven by the bondcoat oxidation. This allows definition of lifetime prediction models representative of the field experience for thin thermal barrier coating systems where the difference between the bondcoat temperature and the coating surface are limited to 100–200 °C. Thick thermal barrier coating systems can experience coating surface temperatures 500 °C higher than the bondcoat temperature. In such cases sintering and phase transformations in the ceramic layers can also affect the coating lifetime. For this reason cyclic test methods like thermal gradient burner rig and laser heat-flux tests have been developed. They allow to test a coating system with surface temperatures >1400 °C while keeping bondcoat temperature <900 °C. The main issue of such tests is the often limited samples statistic, the reproducibility of the test conditions, and the coating failure mode that is not representative of the field experience. In Alstom, a burner rig test has been developed to solve these issues. It allows to test in parallel 10 samples, with a closed loop control system allowing live adjustment of the heat and cooling air input to keep an individually controlled constant thermal gradient with a homogeneous temperature distribution on the sample surface. Modeling of the test has been performed to understand the coating failure mechanism and to adapt the testing conditions such to get a failure mechanism closer to the relevant degradation mechanisms experienced in the field. Testing of coatings coming from the same production batch in various test campaign shows a low scatter in test results confirming that the burner rig test design allowed solving the test reproducibility and samples statistics issues. Examples will be shown how this burner rig test can be used for the development of lifetime prediction rules for thermal barrier coating systems.

The Research of Coat Materials Performance Based on Multi-Scale Method

2011 ◽  
Vol 255-260 ◽  
pp. 3717-3721
Author(s):  
Ke Liang Ren ◽  
Yan Dong ◽  
Yan Chang Wang
Keyword(s):  
Thermal Barrier Coating ◽  
Optimization Design ◽  
Operational Matrix ◽  
Thermal Barrier ◽  
Algebraic Equations ◽  
Coating Materials ◽  
Multi Scale ◽  
Barrier Coating ◽  
The Matrix ◽  
Operational Matrix Of Integration

As for the multi-scale coupling phenomenon among substrate, bonding coat and coating in thermal barrier coating materials, the method of wavelet-based homogenization are used to convert the thermal equilibrium equation into a group of algebraic equations. Using this method, an operational matrix of integration based on the wavelet is established and the procedure for applying the matrix to solve the temperature and displacement are formulated. The results provide a theoretical basic for selecting coating thickness of thermal barrier coating materials in optimization design.

Alumina Growth and Interface Strengthening Mechanisms of Pt on the Surface of Bond Coats in EB-PVD TBC System Based on First-Principles

2016 ◽  
Vol 850 ◽  
pp. 253-258 ◽  
Author(s):  
Yi Qun Wang ◽  
Peng Song ◽  
Hong Xing Liao ◽  
Qiang Ji ◽  
Jian Sheng Lu
Keyword(s):  
Thermal Barrier Coating ◽  
First Principles ◽  
Density Functional ◽  
Oxygen Adsorption ◽  
Thermal Barrier ◽  
Interface Adhesion ◽  
Bond Coats ◽  
Bonding Performance ◽  
Barrier Coating ◽  
The Density Functional Theory

Oxygen adsorption, aluminium segregation and interface adhesion on the surface of NiPtAl and MCrAlY bond coats (BC) in EB-PVD TBC system were investigated using first-principles calculations within the density functional theory (DFT). Examination of oxygen adsorption and aluminium segregation indicated that the addition of Pt always obstructed the growth of alumina. In addition, NiPtAl, as bond coats in EB-PVD TBC System, had less lattice variation and stronger interface adhesion than MCrAlY when alumina was produced. It is found that Pt is an important factor that affects the Al2O3 growth in thermal barrier coating. It is proved that Pt improves the bonding performance of Al2O3 and lifetime of thermal barrier coating. This offsets the high cost of Pt in industry application.

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').

Sign in / Sign up

Export Citation Format

Share Document