Influence of water vapour on the HfO2 distribution within the oxide layer on CoNiCrAlHf alloys

Li, Chao; Song, Peng; Khan, Asghar; Feng, Jing; Chen, Kunlun; Zang, Junjie; Xiong, Xiping; Lu, Jian; Lu, Jiansheng

doi:10.1016/j.jallcom.2017.12.334

Cited by 23 publications

(4 citation statements)

References 33 publications

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“…However, no characteristic peaks of NiFe2O4 are found in the 25% pre-strained alloy, indicating that pre-strain inhibits the formation of NiFe2O4. Furthermore, based on the XRD and EDS analysis (Table 2), it can be concluded that the white oxides observed in Figure 2 are HfO2 which has been proved by other researchers [45]. It should be noted that the oxidation products in different regions of the pre-strained specimens exhibit noticeable differences.…”

Section: Growth Behavior Of Short-term Oxidation Productssupporting

confidence: 60%

Oxidation Behavior of Pre-Strained Polycrystalline Ni3Al-Based Superalloy

Guo,

Ding,

Wang

et al. 2024

Materials

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The harsh service environment of aeroengine hot-end components requires superalloys possessing excellent antioxidant properties. This study investigated the effect of pre-strain on the oxidation behavior of polycrystalline Ni3Al-based superalloys. The growth behaviors of oxidation products were analyzed by scanning electron microscope, transmission electron microscope, X-ray Photoelectron Spectroscopy and Raman spectroscopy. The results indicated that the 5% pre-strained alloys exhibited lower mass gain, shallower oxidation depth and more compact oxide film structures compared to the original alloy. This is mainly attributed to the formation of rapid diffusion paths for Al atoms diffusing to the surface under 5% pre-strain, which promotes the faster formation of protective Al2O3 film while continuing to increase the pre-strain to 25% results in less protective transient oxidation behavior being aggravated due to the increase in dislocation density within the alloy, which prevents the timely formation of the protective Al2O3 film, resulting in uneven oxidation behavior on the alloy.

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Section: Growth Behavior Of Short-term Oxidation Productssupporting

confidence: 60%

Oxidation Behavior of Pre-Strained Polycrystalline Ni3Al-Based Superalloy

Guo,

Ding,

Wang

et al. 2024

Materials

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“…Cyclic oxidation tests were performed in a tube furnace that was equipped with a steam generator. During testing, the content of water vapour in the furnace was 25% [26]. In each oxidation cycle, the specimens were heated in a 1050 • C furnace with air plus water vapour for 15 h and were then removed and cooled in the laboratory (approximately 25 • C) for 1 h. For comparison, cyclic oxidation testing was also conducted in air without the addition of water vapour.…”

Section: Methodsmentioning

confidence: 99%

“…When compared with the samples oxidized in air (Figure 8b), the in situ DBL (Si/Cr-rich phases) in air plus water vapour has a different morphology. The high partial pressure of O (P O ) promoted the lateral growth of the DBL in air plus water vapour, while low P O inhibited its lateral growth in air The Al in the aluminide coating was mainly depleted by the outward diffusion of Al, due to form a Al 2 O 3 scale in air plus water vapour, and the concentration of O (C O(water) ) increased in air plus water vapour due to severe spallation on the oxide scale [26]. High C O(water) decreases the concentration of Al (C Al ) in the aluminide coating too much (32 at.%).…”

Section: Differences In the Diffusion Barrier Layermentioning

confidence: 99%

Destructive Effect of Water Vapour on an In Situ Diffusion Barrier Layer within an Aluminide Coating on IN738 Alloy

Song

Chen

et al. 2018

Coatings

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High-temperature interdiffusion within a hot-dipped aluminide (Al-10 wt.% Si) coating on an IN738 superalloy was investigated at 1050 • C in air and in air plus water vapour. The resulting morphology of in situ diffusion barrier layer (DBL) within the aluminide coating is affected by oxidizing atmospheres; DBL can effectively retard the interdiffusion of aluminium within the coating. The location of the in situ DBL is governed by the partial pressure of oxygen at different depths from the oxide scales in both atmospheres. Meanwhile, the diffusion fluxes of different elements led to DBLs with different morphologies in the aluminide coating on the Ni-based alloy. growth and temperature of the DBL (intermetallic layer) that was formed in Pd/Cu and Pd/Ag porous stainless steel, the DBL formed by the oxidation of the substrate at 430 • C, and the DBL was effective in reducing the intermetallic diffusion at 500 • C. Müller et al. [24] discussed the effects of reactive element oxides and the property of diffusion on a self-forming DBL on nickel-based superalloys, and the DBL was destroyed due to the reaction of Y and Hf from MCrAlY (M = Ni, Co). The above studies indicated that the relationships between the growth, temperatures and reactive element oxides of the DBL, as well as its oxidation resistance, are complex and not yet fully understood at high temperature. Therefore, many factors affect the growth and morphology of the DBL. The relationship between the growth of the DBL and diffusion of elements in different atmospheres requires further study.The purpose of this research was to understand the influence between the in situ DBL and the diffusion of elements during exposure to air and air plus water vapour environment. Moreover, the relationship between the external environment and the growth of DBL has been examined. Coatings 2018, 8, x FOR PEER REVIEW 10 of 11 Author Contributions: Conceptualization, C.L. and P.S.; Methodology, J.L.; Software, X.H.; Validation, K.C., X.Y. and P.S.; Formal Analysis, X.H., K.C. and X.Y.; Investigation, C.L.; Resources, P.S.; Data Curation, J.L.; Writing-Original Draft Preparation, C.L.; Writing-Review & Editing, C.L. and P.S.; Visualization, K.C.; Supervision, P.S. and J.L.; Project Administration, P.S.

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“…Among them one can cite titanium alloys [14], thermal barrier coatings [15] and other ceramic materials [16]. Surprisingly cobalt-based superalloys seem having been forgotten in this set of works, as suggested by the rather low number of articles concerning the effect of water vapour on the high temperature oxidation of cobalt-based superalloys [17][18][19]. The aim of the present work is to investigate the oxidation behaviour at high temperature (900°C) of three selected cast cobalt alloys, more or less complex in terms of chemical composition, in an atmosphere essentially made of water vapour.…”

Section: Introductionmentioning

confidence: 99%

Surface degradation of three Cr-containing cobalt-based alloys exposed to pure water vapour at 900°C

Berthod

Léglise

Aranda

et al. 2020

Corrosion Engineering, Science and Technology

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Three cast cobalt-based alloys containing or not chromium carbides and tantalum carbides were exposed at 900°C to 100% water vapour for 46 or 100 h. The oxidised samples were characterised by XRD, SEM and EDS. Chromia was the main oxide formed in all cases. Spinel oxide appeared on the carbide-free alloy and NiO was also detected on the TaC-containing alloy. Chromia was the single oxide formed on the alloy containing chromium carbides. The scales were thin and the subsurfaces and the bulks were slightly affected by oxidation or thermal exposure. All alloys demonstrated remarkable oxidation resistance but oxide spallation, enhanced maybe by the low thickness of the scales, by the porosities induced by chromia volatilisation, as well as by the CrTaO 4 complex oxide formed at the interface in the case of the TaC-containing alloy, is a critical problem to solve. The Co-10Ni-30Cr-0.5C was the best of the three alloys.

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Influence of water vapour on the HfO2 distribution within the oxide layer on CoNiCrAlHf alloys

Cited by 23 publications

References 33 publications

Oxidation Behavior of Pre-Strained Polycrystalline Ni3Al-Based Superalloy

Oxidation Behavior of Pre-Strained Polycrystalline Ni3Al-Based Superalloy

Destructive Effect of Water Vapour on an In Situ Diffusion Barrier Layer within an Aluminide Coating on IN738 Alloy

Surface degradation of three Cr-containing cobalt-based alloys exposed to pure water vapour at 900°C

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