scholarly journals Thermal Insulation of YSZ and Erbia-Doped Yttria-Stabilised Zirconia EB-PVD Thermal Barrier Coating Systems after CMAS Attack

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4382 ◽  
Author(s):  
Germain Boissonnet ◽  
Christine Chalk ◽  
John R. Nicholls ◽  
Gilles Bonnet ◽  
Fernando Pedraza
Keyword(s):  
Thermal Insulation ◽  
Vapour Deposition ◽  
Thermal Barrier ◽  
Physical Vapour Deposition ◽  
Barrier Coatings ◽  
Barrier Coating ◽  
Ysz Coating ◽  
Calcium Magnesium ◽  
The Impact ◽  
Aluminium Silicates

The impact of small deposits of calcium–magnesium–aluminium silicates (CMAS) on the top of thermal barrier coatings (TBCs) made of yttria-stabilised zirconia (YSZ) produced via electron-beam physical vapour deposition (EB-PVD) is shown to play a role in the microstructural and chemical stability of the coatings; hence, it also affects the thermal insulation potential of TBCs. Therefore, the present work investigates the degradation potential of minor CMAS deposits (from 0.25 to 5 mg·cm−2) annealed at 1250 °C for 1 h on a novel Er2O3-Y2O3 co-stabilised ZrO2 (ErYSZ) EB-PVD TBC, which is compared to the standard YSZ coating. Due to the higher reactivity of ErYSZ coatings with CMAS, its penetration is limited in comparison with the standard YSZ coatings, hence resulting in a better thermal insulation of the former after ageing.

Emittance of Y2O3 stabilised ZrO2 thermal barrier coatings prepared by electron-beam physical-vapour deposition

2000 ◽  
Vol 32 (3) ◽  
pp. 361-368 ◽  
Author(s):  
Jochen Manara ◽  
Rainer Brandt ◽  
Joachim Kuhn ◽  
Jochen Fricke ◽  
Thomas Krell ◽  
...  
Keyword(s):  
Electron Beam ◽  
Thermal Barrier Coatings ◽  
Vapour Deposition ◽  
Thermal Barrier ◽  
Physical Vapour Deposition ◽  
Barrier Coatings

Solid particle erosion of thermal spray and physical vapour deposition thermal barrier coatings

Wear ◽  
2011 ◽  
Vol 271 (11-12) ◽  
pp. 2909-2918 ◽  
Author(s):  
F. Cernuschi ◽  
L. Lorenzoni ◽  
S. Capelli ◽  
C. Guardamagna ◽  
M. Karger ◽  
...  
Keyword(s):  
Thermal Spray ◽  
Solid Particle ◽  
Thermal Barrier Coatings ◽  
Vapour Deposition ◽  
Thermal Barrier ◽  
Solid Particle Erosion ◽  
Physical Vapour Deposition ◽  
Particle Erosion ◽  
Barrier Coatings

scholarly journals Modelling evaporation in electron-beam physical vapour deposition of thermal barrier coatings

2021 ◽  
Author(s):  
Julie Chevallier ◽  
Luis Isern ◽  
Koldo Almandoz Forcen ◽  
Christine Chalk ◽  
John R. Nicholls
Keyword(s):  
Electron Beam ◽  
Thermal Barrier Coatings ◽  
Computational Models ◽  
Evaporation Rate ◽  
Vapour Deposition ◽  
Thermal Barrier ◽  
Physical Vapour Deposition ◽  
Local Composition ◽  
Barrier Coatings ◽  
Compositional Segregation

AbstractThis work presents computational models of ingot evaporation for electron-beam physical vapour deposition (EB-PVD) that can be applied to the deposition and development of thermal barrier coatings (TBCs). TBCs are insulating coatings that protect aero-engine components from high temperatures, which can be above the component’s melting point. The development of advanced TBCs is fuelled by the need to improve engine efficiency by increasing the engine operating temperature. Rare-earth zirconates (REZ) have been proposed as the next-generation TBCs due to their low coefficient of thermal conductivity and resistance to molten calcium-magnesium alumina-silicates (CMAS). However, the evaporation of REZ has proven to be challenging, with some coatings displaying compositional segregation across their thickness. The computational models form part of a larger analytical model that spans the whole EB-PVD process. The computational models focus on ingot evaporation, have been implemented in MATLAB and include data from 6 oxides: ZrO2, Y2O3, Gd2O3, Er2O3, La2O3 and Yb2O3. Two models (2D and 3D) successfully evaluate the evaporation rates of constituent oxides from multiple-REZ ingots, which can be used to highlight incompatibilities and preferential evaporation of some of these oxides. A third model (local composition activated, LCA) successfully predicts the evaporation rate of the whole ingot and replicates the cyclic change in composition of the evaporated plume, which is manifested as changes in compositional segregation across the coating’s thickness. The models have been validated with experimental data from Cranfield University’s EB-PVD coaters, published vapour pressure calculations and evaporation rate formulas described in the literature.

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