Size effects on high temperature oxidation of MCrAlY coatings processed via APS and HVOF depositions

Kalush, Ali; Texier, Damien; Ecochard, Maxime; Sirvin, Quentin; Choquet, Karim; Gheno, Thomas; Vanderesse, Nicolas; Jomaa, Walid; Bocher, Philippe

doi:10.1016/j.surfcoat.2022.128483

Cited by 20 publications

(4 citation statements)

References 51 publications

(100 reference statements)

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“…It is also understandable that the heat-treatment temperatures (900-1500 K) used in industry are intermediate within the theoretical range (600-1600 K), because a too-low temperature limits the microstructural evolutions (e.g., grain growth and precipitation) during an industrial processing time (from minutes to 24 h), and a too high temperature makes the microstructure kinetically over excited and unfavored for meticulous tuning. In thermal barrier coatings for gas turbines, the optimized compositions for bond-coat NiCrAlY and NiCrCoAlY (x Cr = 16-22 at%) 4,[89][90][91][92][93] should also comply with such thermodynamic principles.…”

Section: Free Energies Of Formation For Alloys and Compoundsmentioning

confidence: 99%

Elemental partitioning and corrosion resistance of Ni–Cr alloys revealed by accurate ab-initio thermodynamic and electrochemical calculations

Huang,

Xie,

Sieradzki

et al. 2023

npj Mater Degrad

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Elemental partitioning during thermal processing can significantly affect the corrosion resistance of bulk alloys operating in aggressive electrochemical environments, for which, despite decades of experimental and theoretical studies, the thermodynamic and electrochemical mechanisms still lack accurate quantitative descriptions. Here, we formulate an ab initio thermodynamic model to obtain the composition- and temperature-dependent free energies of formation (ΔfG) for Ni–Cr alloys, a prototypical group of corrosion-resistant metals, and discover two equilibrium states that produce the driving forces for the elemental partitioning in Ni–Cr. The results are in quantitative agreement with the experimental studies on the thermodynamic stability of Ni–Cr. We further construct electrochemical (potential–pH) diagrams by obtaining the required ΔfG values of native oxides and (oxy)hydroxides using high-fidelity ab-initio calculations that include exact electronic exchange and phononic contributions. We then analyze the passivation and electrochemical trends of Ni–Cr alloys, which closely explain various oxide-film growth and corrosion behaviors observed on alloy surfaces. We finally determine the optimal Cr content range of 14–34 at%, which provides the Ni–Cr alloys with both the preferred heat-treatment stability and superior corrosion resistance. We conclude by discussing the consequences of these findings on other Ni–Cr alloys with more complex additives, which can guide the further optimization of industrial Ni–Cr-based alloys.

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Section: Free Energies Of Formation For Alloys and Compoundsmentioning

confidence: 99%

Elemental partitioning and corrosion resistance of Ni–Cr alloys revealed by accurate ab-initio thermodynamic and electrochemical calculations

Huang,

Xie,

Sieradzki

et al. 2023

npj Mater Degrad

View full text Add to dashboard Cite

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“…The high temperatures used in the coating process ensure that the molten or semi-molten particles have significant thermal energy. The coating particles are delivered to the substrate surface at a rate of 500 to 800 m/s (Kalush et al, 2022;. The negative effects brought on by high temperatures are lessened by the fact that the temperature is lower than the plasma spray coating process.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Hot Corrosion Behavior of WC-Co-Cr Coatings Coated by the HVOF Method

Ozgurluk

2023

Journal of Materials and Mechatronics: A

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Thermal spray coating techniques have wide-ranging applications in various fields, including marine, automotive, biomedical, and aerospace industries. These methods are popularly used because materials coated with thermal spray coatings exhibit excellent resistance to oxidation, erosion, corrosion, and abrasive environments, particularly at high temperatures. The present study utilized the high-speed oxy-fuel (HVOF) technique, a state-of-the-art thermal spray coating method, to apply a hard cermet ceramic coating material consisting of WC-Co-Cr onto a 316L stainless steel substrate. Isothermal hot corrosion tests were also conducted at 750°C in the presence of 45% Na2SO4 and 55% V2O5 hot corrosion salts for 1, 3, and 5 hours. Advanced characterization techniques such as X-Ray Diffractometry (XRD), Energy Dispersive Spectrum (EDS), scanning electron microscopy (SEM), and elemental mapping analysis devices were used to characterize the samples coated with the HVOF technique before and after hot corrosion tests. The findings indicate that WC-Co-Cr hard coatings, which are known for their high resistance to abrasion, sustain severe damage at high temperatures. The coating was damaged after 5 hours in the hot corrosion tests performed in the presence of V2O5 and Na2SO4 molten salt at 750°C.

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“…Thermal Barrier Coating (TBC) can protect critical areas such as turbine blades and combustion chambers due to its excellent resistance to high temperatures [1][2][3]. A bonded coating (BC) and a ceramic top coat (TC) are usually applied to the surface of a hightemperature nickel-based alloy forming the TBC [4,5].…”

Section: Introductionmentioning

confidence: 99%

Effect of Interface Curvature on Local Growth Behavior and Stress of Thermal Barrier Coatings

Wang,

Yu,

Zhang

et al. 2023

Coatings

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It is well known that coating spalling often occurs between the top ceramic coating (TC) and the metal bonding coating (BC) during the working process where the thermal mismatch stress between the layers plays a key role. Dynamic changes in the thermally grown oxide (TGO) between the facing and bonding layers during thermal cycling increase the thermal mismatch at the interface. The effect of oxide thickening on localized mismatch stresses under thermal cycling with different interfacial curvatures is quantitatively investigated using numerical methods in this paper. A dynamic growth model of the oxide was developed based on the consideration of the composition and morphology of the thermally grown oxide. The results show that TGO growth behavior, local stress evolution, crack initiation location, and crack propagation length are influenced by the interface curvature at the same aspect ratio. The interface between the oxide layer and the bonding layer gradually developed significant tensile to dangerous stresses during thermal cycling. These tensile stresses are predominantly distributed at the crest during the early stages of thermal exposure and gradually transferred to the near-peak (the region near the peak) and ramp regions (the region in between the peak and the valley) as the oxidation process progressed. The crack initiation and propagation phenomenon can be observed at various regions during thermal exposure. Increasing interface curvature leads to an earlier dangerous stress moment in the ramp area due to higher maximum tensile stress. Therefore, the small changes in the interface curvature severely affected the location and time of crack initiation and the crack length.

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Size effects on high temperature oxidation of MCrAlY coatings processed via APS and HVOF depositions

Cited by 20 publications

References 51 publications

Elemental partitioning and corrosion resistance of Ni–Cr alloys revealed by accurate ab-initio thermodynamic and electrochemical calculations

Elemental partitioning and corrosion resistance of Ni–Cr alloys revealed by accurate ab-initio thermodynamic and electrochemical calculations

Evaluation of Hot Corrosion Behavior of WC-Co-Cr Coatings Coated by the HVOF Method

Effect of Interface Curvature on Local Growth Behavior and Stress of Thermal Barrier Coatings

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