Impact of superalloy composition, bond coat roughness and water vapor on TBC lifetime with HVOF NiCoCrAlYHfSi bond coatings

2013 ◽  
Vol 237 ◽  
pp. 65-70 ◽  
Author(s):  
J.A. Haynes ◽  
K.A. Unocic ◽  
M.J. Lance ◽  
B.A. Pint
Keyword(s):  
Water Vapor ◽  
Bond Coat ◽  
Bond Coatings ◽  
Tbc Lifetime

Effect of increased water vapor levels on TBC lifetime with Pt-containing bond coatings

2011 ◽  
Vol 206 (7) ◽  
pp. 1566-1570 ◽  
Author(s):  
B.A. Pint ◽  
G.W. Garner ◽  
T.M. Lowe ◽  
J.A. Haynes ◽  
Y. Zhang
Keyword(s):  
Water Vapor ◽  
Bond Coatings ◽  
Tbc Lifetime

The Effect of Environment on TBC Lifetime

2015 ◽  
Author(s):  
Bruce A. Pint ◽  
Kinga A. Unocic ◽  
J. Allen Haynes
Keyword(s):  
Water Vapor ◽  
Carbon Capture ◽  
Air Plasma ◽  
Combustion Gas ◽  
Bond Coatings ◽  
Barrier Coating ◽  
Coating Failure ◽  
Negative Effect ◽  
Plasma Sprayed ◽  
Tbc Lifetime

While the water vapor content of the combustion gas in natural gas-fired land based turbines is ∼10%, it can be 20–85% with coal-derived (syngas or H2) fuels or innovative turbine concepts for more efficient carbon capture. Additional concepts envisage working fluids with high CO2 contents to facilitate carbon capture and sequestration. To investigate the effects of changes in the gas composition on thermal barrier coating (TBC) lifetime, furnace cycling tests (1 and 100h cycles) were performed in air with 10, 50 and 90 vol.% water vapor and CO2-10%H2O and compared to prior results in dry air or O2. Two types of TBC’s were investigated: (1) diffusion bond coatings (Pt diffusion or Pt-modified aluminide) with commercial electron-beam physical vapor-deposited yttria-stabilized zirconia (YSZ) top coatings on second-generation superalloy N5 and N515 substrates and (2) high velocity oxygen fuel (HVOF) sprayed MCrAlYHfSi bond coatings with air-plasma sprayed YSZ top coatings on superalloys X4, 1483 or 247 substrates. For both types of coatings exposed in 1h cycles, the addition of water vapor resulted in a decrease in coating lifetime, except for Pt diffusion coatings which were unaffected by the environment. In 100h cycles, environment was less critical, perhaps because coating failure was chemical (i.e. due to interdiffusion) rather than mechanical. In both 1h and 100h cycles, CO2 did not appear to have any negative effect on coating lifetime.

scholarly journals The Effect of Environment on Thermal Barrier Coating Lifetime

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Bruce A. Pint ◽  
Kinga A. Unocic ◽  
J. Allen Haynes
Keyword(s):  
Water Vapor ◽  
Thermal Barrier Coating ◽  
Carbon Capture ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Combustion Gas ◽  
Bond Coatings ◽  
Barrier Coating ◽  
Negative Effect ◽  
Plasma Sprayed

While the water vapor content of the combustion gas in natural gas-fired land-based turbines is ∼10%, it can be 20–85% with coal-derived (syngas or H2) fuels or innovative turbine concepts for more efficient carbon capture. Additional concepts envisage working fluids with high CO2 contents to facilitate carbon capture and sequestration. To investigate the effects of changes in the gas composition on thermal barrier coating (TBC) lifetime, furnace cycling tests (1-h and 100-h cycles) were performed in air with 10, 50, and 90 vol. % water vapor and CO2-10% H2O and compared to prior results in dry air or O2. Two types of TBCs were investigated: (1) diffusion bond coatings (Pt-diffusion or Pt-modified aluminide) with commercial electron-beam physical vapor-deposited yttria-stabilized zirconia (YSZ) top coatings on second-generation superalloy N5 and N515 substrates and (2) high-velocity oxygen fuel (HVOF) sprayed MCrAlYHfSi bond coatings with air plasma-sprayed YSZ top coatings on superalloys X4, 1483, or 247 substrates. For both types of coatings exposed in 1-h cycles, the addition of water vapor resulted in a decrease in coating lifetime, except for Pt-diffusion coatings which were unaffected by the environment. In 100-h cycles, environment was less critical, perhaps because coating failure was chemical (i.e., due to interdiffusion) rather than mechanical. In both 1-h and 100-h cycles, CO2 did not appear to have any negative effect on coating lifetime.

scholarly journals Kinetic Monte Carlo Simulations of Oxygen Diffusion in Environmental Barrier Coating Materials

MRS Advances ◽  
2018 ◽  
Vol 3 (10) ◽  
pp. 511-518 ◽  
Author(s):  
Brian S. Good
Keyword(s):  
Monte Carlo ◽  
Water Vapor ◽  
Bond Coat ◽  
Oxygen Diffusion ◽  
Kinetic Monte Carlo ◽  
Ceramic Matrix Composite ◽  
Low Oxygen ◽  
Coating Materials ◽  
Environmental Barrier ◽  
Oxygen Diffusivity

ABSTRACTCeramic Matrix Composite (CMC) materials are of interest for use in next-generation turbine engine components, offering a number of significant advantages, including reduced weight and high operating temperatures. However, in the hot environment in which such components operate, the presence of water vapor can lead to corrosion and recession, limiting the useful life of the components. Such degradation can be reduced through the use of Environmental Barrier Coatings (EBCs) that limit the amount of oxygen and water vapor reaching the component. Candidate EBC materials include Yttrium and Ytterbium silicates. In this work we present results of kinetic Monte Carlo (kMC) simulations of oxygen diffusion, via the vacancy mechanism, in Yttrium and Ytterbium disilicates, along with a brief discussion of interstitial diffusion.An EBC system typically includes a bond coat located between the EBC and the component surface. Bond coat materials are generally chosen for properties other than low oxygen diffusivity, but low oxygen diffusivity is nevertheless a desirable characteristic, as the bond coat could provide some additional component protection, particularly in the case where cracks in the coating system provide a direct path from the environment to the bond coat interface. We have therefore performed similar kMC simulations of oxygen diffusion in this material.

Microstructural Evolution of Durable Thermal Barrier Coatings with Hf and/or Y Modified CMSX-4TM Superalloy Substrates

2007 ◽  
Vol 539-543 ◽  
pp. 1206-1211 ◽  
Author(s):  
J. Liu ◽  
Yong Ho Sohn ◽  
K.S. Murphy
Keyword(s):  
Thermal Barrier Coatings ◽  
Bond Coat ◽  
Thermal Cycle ◽  
Thermal Barrier ◽  
Growth Constant ◽  
Cross Sectional ◽  
Barrier Coatings ◽  
Forced Air ◽  
Parabolic Growth Constant ◽  
Tbc Lifetime

Thermal cyclic lifetime and microstructural degradation of thermal barrier coatings (TBCs) with (Ni,Pt)Al bond coat and Hf- and/or Y-modified CSMX-4 superalloy substrates were examined. Thermal cyclic lifetime of TBCs was measured using a furnace thermal cycle test that consisted of 10-minute heat-up, 50-minute dwell at 1135°C, and 10-minute forced-air-quench. TBC lifetime was observed to improve from 600 cycles to over 3200 cycles with appropriate Hf- and/or Y-alloying of CMSX-4 superalloys. This significant improvement in TBC lifetime is the highest reported lifetime in literature with similar testing parameters. Cross-sectional microstructure of TBC specimens were examined by scanning electron microscopy (SEM) after the spallation failure. While undulation of TGO/bond coat interface (e.g., rumpling and racheting) was observed to be main damage mechanisms for TBCs on baseline CMSX-4, the same interface remained relatively flat for durable TBCs on Hf- and/or Y-modified CSMX-4. The parabolic growth constant of the TGO scale was slightly lower for TBCs with Hfand/ or Y-modified CSMX-4.

scholarly journals High-Temperature Oxidation Resistance of PDC Coatings in Synthetic Air and Water Vapor Atmospheres

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2388
Author(s):  
Milan Parchovianský ◽  
Ivana Parchovianská ◽  
Peter Švančárek ◽  
David Medveď ◽  
Mateus Lenz-Leite ◽  
...  
Keyword(s):  
Water Vapor ◽  
Bond Coat ◽  
Protective Coatings ◽  
Temperature Oxidation ◽  
Oxidative Resistance ◽  
Strong Adhesion ◽  
Different Temperatures ◽  
Water Vapor Atmosphere ◽  
Scratch Tests ◽  
Steel Substrates

This work is aimed at the development and investigation of the oxidation behavior of ferritic stainless-steel grade AISI 441 and polymer-derived ceramic (PDC) protective coatings. Double-layer coatings of a PDC bond coat below a PDC top coat with glass and ceramic passive fillers’ oxidative resistance were studied at temperatures up to 1000 °C in a flow-through atmosphere of synthetic air and in air saturated with water vapor. Investigation of the oxide products formed at the surface of the samples in synthetic air and water vapor atmospheres, at different temperatures (900, 950, 1000 °C) and exposure times (24, 96 h) was carried out on both uncoated steel and steel coated with selected coatings by scanning electron microscopy (SEM) and X-Ray diffraction (XRD). The Fe, Cr2O3, TiO2, and spinel (Mn,Cr)3O4 phases were identified by XRD on oxidized steel substrates in both atmospheres. In the cases of the coated samples, m- ZrO2, c- ZrO2, YAG, and crystalline phases (Ba(AlSiO4)2–hexacelsian, celsian) were identified. Scratch tests performed on both coating compositions revealed strong adhesion after pyrolysis as well as after oxidation tests in both atmospheres. After testing in the water vapor atmosphere, Cr ions diffused through the bond coat, but no delamination of the coatings was observed.

scholarly journals The effect of cycle frequency, H2O and CO2 on TBC lifetime with NiCoCrAlYHfSi bond coatings

2014 ◽  
Vol 260 ◽  
pp. 107-112 ◽  
Author(s):  
M.J. Lance ◽  
K.A. Unocic ◽  
J.A. Haynes ◽  
B.A. Pint
Keyword(s):  
Cycle Frequency ◽  
Bond Coatings ◽  
Tbc Lifetime
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