Investigation of Element Effect on High Temperature Oxidation of HVOF NiCoCrAlX Coatings

Zhang, Pimin; Peng, Ru Lin; Li, Xinhai; Johansson, Sten

doi:10.20944/preprints201803.0105.v1

Cited by 4 publications

(3 citation statements)

References 35 publications

(50 reference statements)

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“…which suppresses the extent of internal oxidation in coating. The addition of Ru in MCrAlY also achieves a similar effect as reported in Ref [130].…”

Section: Coating-superalloy Interdiffusion 33supporting

confidence: 79%

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Performance of MCrAlX coatings : Oxidation, Hot corrosion and Interdiffusion

Zhang

2019

Linköping Studies in Science and Technology. Dissertations

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MCrAlY coatings (M=Ni and/or Co) are widely used for the protection of superalloy components against oxidation and hot corrosion in the hot sections of gas turbines. The drive for coating systems to bestow adequate oxidation and corrosion resistance upon the components becomes urgent as an inevitable result of the necessary improvement in engine combustion efficiency and service lifetime. Through careful design of the composition, MCrAlY coating performance can be optimized to meet the needs under different service conditions and component materials, therefore, "MCrAlX", with "X" standing for the minor alloying elements, is used to highlight the effect. In the present thesis, the performance of new MCrAlX coatings is investigated with respect to oxidation, hot corrosion and interactions between coating-superalloy substrates.Coating performance can be affected by many factors, where their impacts may vary at different oxidation stages, therefore experiments are designed by targeting each stage. Investigation on the initial stage oxidation behavior of MCrAlY coatings with post-deposition surface treatments reveals the different growth mechanisms of alumina scales. Results showed that surface treatments significantly reduce the alumina growth rate by suppressing transient alumina development and aiding the early formation of α-Al 2 O 3 , which improves the long-term oxidation performance of the coating. Similarly, the modification of minor alloy elements in MCrAlX coatings also yields a similar effect. Subsequently, study on the oxidation behavior of new MCrAlX coatings is carried out at the steady oxidation stage, followed by the microstructure observation, and thermodynamic and kinetic simulations. As an alternative reactive element to Y, Ce shows a negative effect on the formation of columnar alumina scales of high strain tolerance. In comparison, Fe or Ru addition shows no influence on alumina growth, rather than strengthening the phase stability in the coating and reducing the interdiffusion between coating-substrate through different mechanisms. As the oxidation proceeds to the close-to-end stage, a reliable criterion to estimate the capability of coating to form α-Al 2 O 3 is of great importance to accurately evaluate coating lifetime. A iii iv temperature-dependent critical Al-activity criterion is proposed to better predict the formation of a continuous α-Al 2 O 3 scale based on correction of the elemental activity using commercial thermodynamic databases to replace the empirical Al-concentration based criterion.Severe interdiffusion occurs between coating-substrate during high temperature oxidation, accelerating the degradation of the system. Interdiffusion behavior of diffusion couples of superalloys-MCrAlX coatings are examined. It is highlighted that the the recrystallization of superficial layer of the substrate contributes to the secondary reaction zone formation and element interdiffusion controls subsequent zone thickening.Study on Type I hot corrosion behavior of new MCrAlX coatings shows that the ...

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“…which suppresses the extent of internal oxidation in coating. The addition of Ru in MCrAlY also achieves a similar effect as reported in Ref [130].…”

Section: Coating-superalloy Interdiffusion 33supporting

confidence: 79%

“…Diffusion module of Thermo-Calc software package, DICTRA, is quite handy to investigate the short-range and long-range diffusion behaviour. For instance, it demonstrated the positive effect of Ru on stabilizing β phase [130].…”

Section: Thermodynamic and Kinetic Modellingmentioning

confidence: 99%

Performance of MCrAlX coatings : Oxidation, Hot corrosion and Interdiffusion

Zhang

2019

Linköping Studies in Science and Technology. Dissertations

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“…Abrasive damage, erosion by solid particles and corrosion are the most frequently described damage processes in literature [13][14][15][16]. Despite the fact that the HVOF method is widely used for metallic or cermet coating deposition [7,9,15,[17][18][19][20], the anti-wear properties of HVOF coatings are still being investigated. New studies on the abrasive wear of thermally deposited coatings are published, and even though these issues seem to be quite well-known there are relatively few scientific reports combining both sliding and cavitation testing of HVOF metallic coatings.…”

Section: Introductionmentioning

confidence: 99%

Resistance to Cavitation Erosion and the Sliding Wear of MCrAlY and NiCrMo Metallic Coatings

Szala

Walczak

Łatka

et al. 2020

2nd Coatings and Interfaces Web Conference (CIWC-2 2020)

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Bulk cobalt- and nickel-based metallic materials exhibit superior resistance to cavitation erosion and sliding wear. Thus, thermally deposited High-Velocity Oxygen Fuel (HVOF) coatings seem promising for increasing the wear resistance of the bulk metal substrate. However, the effect of chemical composition on the cavitation erosion and sliding wear resistance of M(Co,Ni)CrAlY and NiCrMo coatings has not yet been exhaustively studied. In this study, High-Velocity Oxygen Fuel (HVOF) coatings such as CoNiCrAlY, NiCoCrAlY, and NiCrMoFeCo were deposited on AISI 310 (X15CrNi25-20) steel coupons. The microstructure, hardness, phase composition and surface morphology of the as-sprayed coatings were examined. Cavitation erosion tests were conducted using the vibratory method in accordance with the ASTM G32 standard. Sliding wear was examined with the use of a ball-on-disc tribometer, and friction coefficients were measured. The mechanism of wear was identified with the scanning electron microscope equipped with an energy dispersive spectroscopy (SEM-EDS) method. In comparison to the NiCrMoFeCo coating, the CoNiCrAlY and NiCoCrAlY coatings have a lower sliding and cavitation wear resistance.

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Structure and Tribological Properties of Ni–Cr–Al-Based Gradient Coating Prepared by Detonation Spraying

et al. 2021

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In this paper, Ni–Cr–Al coatings were deposited using the detonation spraying method. The aim was to investigate how technological parameters influence coating structure formation, phase composition and tribological performances. We observed that the degree to which the barrel is filled with an O2/C2H2 gas mixture strongly influences the chemical composition of manufactured coatings. High degrees of barrel filling led to a decrease in aluminum content in the coating. Filling degrees of 40% and 50% produced sprayed coatings in which only Ni–Cr phases could be found. When the filling degree was reduced up to 25%, Ni–Al phases began to form in the sprayed coatings. Gradient Ni–Cr–Al coatings were produced by gradually reducing the filling degree from 50% to 25%. These coatings are characterized by Ni–Cr near the substrate level with Ni–Cr and Ni–Al phases at higher levels. The results obtained confirm that gradient Ni–Cr–Al coatings exhibit high hardness as well as good wear resistance.

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Investigation of Element Effect on High Temperature Oxidation of HVOF NiCoCrAlX Coatings

Cited by 4 publications

References 35 publications

Performance of MCrAlX coatings : Oxidation, Hot corrosion and Interdiffusion

Performance of MCrAlX coatings : Oxidation, Hot corrosion and Interdiffusion

Resistance to Cavitation Erosion and the Sliding Wear of MCrAlY and NiCrMo Metallic Coatings

Structure and Tribological Properties of Ni–Cr–Al-Based Gradient Coating Prepared by Detonation Spraying

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