Exploring failure modes of alumina scales on FeCrAl and FeNiCrAl alloys in a nitriding environment

Mortazavi, Anna N.; Esmaily, Mohsen; Geers, Christine; Birbilis, Nick; Svensson, Jan‐Erik; Halvarsson, Mats; Chandrasekaran, Dilip; Johansson, Lars‐Gunnar

doi:10.1016/j.actamat.2020.09.058

Cited by 20 publications

(7 citation statements)

References 49 publications

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“…Also, it was reported that FeCrAl(RE) alloys tend to develop such scale imperfections at RE-rich inclusions in the alloy. Moreover, it has been shown that the tendency to act as points-of-entry for nitrogen increases steeply with inclusion size, RE inclusions smaller than a critical size not causing nitridation [31]. In accordance to [31] and [32], it is argued that the relative vulnerability of alloy APMT towards nitridation in comparison to EF101 and EF100, as evidenced in this study, can be attributed to the occurrence of a small number of large RE-inclusions in the former alloy.…”

Section: The Alumina-forming Alloyssupporting

confidence: 78%

“…Moreover, it has been shown that the tendency to act as points-of-entry for nitrogen increases steeply with inclusion size, RE inclusions smaller than a critical size not causing nitridation [31]. In accordance to [31] and [32], it is argued that the relative vulnerability of alloy APMT towards nitridation in comparison to EF101 and EF100, as evidenced in this study, can be attributed to the occurrence of a small number of large RE-inclusions in the former alloy. These large inclusions disturb the formation of the alumina layer, causing cracks that do not easily heal in the very dry N 2 + H 2 exposure environment.…”

Section: The Alumina-forming Alloyssupporting

confidence: 78%

“…5 and 6 shows that APMT features a population of very large RE-rich inclusions in the alloy which is lacking in EF101. Working at 900 °C, Mortazavi et al [31] showed that nitridation of alumina-forming alloys in N 2 + H 2 environment is associated with imperfections in the alumina layer, the layer itself being practically impermeable to nitrogen. Also, it was reported that FeCrAl(RE) alloys tend to develop such scale imperfections at RE-rich inclusions in the alloy.…”

Section: The Alumina-forming Alloysmentioning

confidence: 99%

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A Comparison of the Oxidation and Nitridation Properties of Selected Chromia- and Alumina-Forming Alloys at 800 °C

et al. 2022

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Three FeCrAl alloys and two chromia-formers (a stainless steel, and a Ni-base alloy) have been exposed in four environments (dry air, air + 20% H2O, 20% H2 + 20% H2O + Ar and 95% N2 + 5% H2) for 168 h at 800 °C. The corroded samples were investigated by SEM/EDS, XRD and gravimetry, and the formation of CrO2(OH)2(g) was measured as a function of time using a denuder technique. The Fe-base alloy formed a Cr-rich protective oxide scale in dry air and wet air but suffered break-away oxidation in 20% H2 + 20% H2O + Ar. In contrast, the Ni-base alloy suffered extensive NiO formation and internal oxidation in dry air and wet air but formed a protective chromia scale in 20% H2 + 20% H2O. All three FeCrAl alloys formed protective alumina scales in dry air, wet air and 20% H2 + 20% H2O + Ar. The FeCrAl alloy Kanthal APMT was severely nitrided in the 95% N2 + 5% H2 environment due to defects in the oxide scale associated with RE-rich inclusions which allowed nitrogen to enter the alloy. In contrast, the two Cr-lean FeCrAl alloys Kanthal EF101 and Kanthal EF100 did not suffer nitridation at all.

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Section: The Alumina-forming Alloyssupporting

confidence: 78%

Section: The Alumina-forming Alloyssupporting

confidence: 78%

Section: The Alumina-forming Alloysmentioning

confidence: 99%

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A Comparison of the Oxidation and Nitridation Properties of Selected Chromia- and Alumina-Forming Alloys at 800 °C

et al. 2022

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“…Locally enhanced inward growth of the alumina surface layer, as evidenced in the present case both by Kanthal ® APMT and by the Kanthal ® APMT/YAG:Ce 3+ composite, is frequently reported for FeCrAl(RE) alloys at high temperature. 14 It is noted that the CTE mismatch may have deleterious effects on the ability of the composite to withstand oxidation under thermal cycling.…”

Section: Resultsmentioning

confidence: 99%

Phosphor Thermometry of Alumina-Forming High-Temperature Alloys Using Luminescent Rare-Earth Ions in YAG: Proof of Concept Using a Dispersion of Ce³⁺ -Doped YAG Particles in a FeCrAl Alloy

Yangui

Sand²,

Helander³

et al. 2023

ECS J. Solid State Sci. Technol.

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Most high-temperature processes require monitoring and controlling temperature, preferably with high precision and good lateral resolution. Here we evaluate the use of the technique commonly known as phosphor thermometry, which exploits the temperature dependent photoluminescence from an inorganic phosphor, for the determination of the temperature of a composite material consisting of the metallic alloy FeCrAl dispersed with phosphor particles of yttrium aluminum garnet (Y3Al5O12, YAG) doped with a small amount of luminescent Ce3+ ions (YAG:Ce3+). The results show that with some optimization and by changing the dopant ion, YAG-based phosphor particles offer a unique opportunity to measure the surface temperature of metal alloys with high precision and high lateral resolution, all the way up to the maximum working temperature of alumina-forming high temperature alloys at ca. 1300°C.

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“…It is known that nickel aluminides and iron aluminides are resistant to oxidation and carburization up to temperatures of around 1000 °C [ 20 , 21 ]. However, studies describing the resistance of aluminides to nitridation are not widely reported [ 22 ]. Recently, nitriding of iron aluminides to increase the hardness of such phases or alloys based on these phases has been reported with growing frequency [ 23 , 24 , 25 , 26 ].…”

Section: Introductionmentioning

confidence: 99%

Resistance of Aluminide Coatings on Austenitic Stainless Steel in a Nitriding Atmosphere

2021

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A new slurry cementation method was used to produce silicide-aluminide protective coatings on austenitic stainless steel 1.4541. The slurry cementation processes were carried out at temperatures of 800 and 1000 °C for 2 h with and without an additional oxidation process at a temperature of 1000 °C for 5 min. The microstructure and thickness of the coatings were studied by scanning electron microscopy (SEM). The intention was to produce coatings that would increase the heat resistance of the steel in a nitriding atmosphere. For this reason, the produced coatings were subjected to gas nitriding at a temperature of 550–570 °C in an atmosphere containing from 40 to 60% of ammonia. The nitriding was carried out using four time steps: 16, 51, 124, and 200 h, and microstructural observations using SEM were performed after each step. Analysis of the chemical composition of the aluminide coatings and reference sample was performed using wavelength (WDS) and energy (EDS) dispersive X-ray microanalysis, and phase analysis was carried out using X-ray diffraction (XRD). The resistance of the aluminide coatings in the nitriding atmosphere was found to depend strongly on the phase composition of the coating. The greatest increase in resistance to gas corrosion under nitriding atmosphere conditions was achieved using a manufacturing temperature of 1000 °C.

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Exploring failure modes of alumina scales on FeCrAl and FeNiCrAl alloys in a nitriding environment

Cited by 20 publications

References 49 publications

A Comparison of the Oxidation and Nitridation Properties of Selected Chromia- and Alumina-Forming Alloys at 800 °C

A Comparison of the Oxidation and Nitridation Properties of Selected Chromia- and Alumina-Forming Alloys at 800 °C

Phosphor Thermometry of Alumina-Forming High-Temperature Alloys Using Luminescent Rare-Earth Ions in YAG: Proof of Concept Using a Dispersion of Ce³⁺ -Doped YAG Particles in a FeCrAl Alloy

Resistance of Aluminide Coatings on Austenitic Stainless Steel in a Nitriding Atmosphere

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Exploring failure modes of alumina scales on FeCrAl and FeNiCrAl alloys in a nitriding environment

Cited by 20 publications

References 49 publications

A Comparison of the Oxidation and Nitridation Properties of Selected Chromia- and Alumina-Forming Alloys at 800 °C

A Comparison of the Oxidation and Nitridation Properties of Selected Chromia- and Alumina-Forming Alloys at 800 °C

Phosphor Thermometry of Alumina-Forming High-Temperature Alloys Using Luminescent Rare-Earth Ions in YAG: Proof of Concept Using a Dispersion of Ce3+ -Doped YAG Particles in a FeCrAl Alloy

Resistance of Aluminide Coatings on Austenitic Stainless Steel in a Nitriding Atmosphere

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Phosphor Thermometry of Alumina-Forming High-Temperature Alloys Using Luminescent Rare-Earth Ions in YAG: Proof of Concept Using a Dispersion of Ce³⁺ -Doped YAG Particles in a FeCrAl Alloy