The Effect of Trace Amounts of Mg in FeCrAl Alloys on the Microstructure of the Protective Alumina Surface Scales

Untoro, Pudji; Dani, Mohammad; Klaar, Hans Joachim; Mayer, Joachim; Naumenko, D.; Kuo, Jui‐Chao; Quadakkers, Willem J.

doi:10.1002/3527600531.ch26

Cited by 8 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…S TUDIES of the effects of reactive elements (RE) on the oxidation behavior of FeCrAl-type alloys have been ongoing for 40 years. This type of alloy is of interest not only for applications such as heating elements and as catalyst supports for both automotive catalytic converters 28,32,41,51,56,57 and catalytic combustion, but also as a model former of alumina. Many of the early studies sought to explain the RE effect by comparing the performance of RE-doped alloys to undoped alloys.…”

Section: Introductionmentioning

confidence: 99%

“…This type of work produced numerous hypotheses about the RE effect 58 -62 and has greatly increased the level of understanding about critical factors important for the formation, growth, and adhesion of alumina scales. More recent studies have used 18 O tracers, 29,34,[63][64][65] photograph-stimulated laser spectroscopy (PSLS), 47,48 and transmission electron microscopy (TEM) 19,20,34,35,38,40,42,45,49,51,53,54,56 to more carefully study the RE effect. However, these comparative or mechanistic studies rarely discussed the relative performance of RE additions or how to optimize the effects for alloy development.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Optimization of Reactive‐Element Additions to Improve Oxidation Performance of Alumina‐Forming Alloys

Pint¹

2003

Journal of the American Ceramic Society

250

View full text Add to dashboard Cite

It is well‐known that the addition of reactive elements (including yttrium, zirconium, lanthanum, cerium, and hafnium) improve the high‐temperature oxidation performance of alumina‐forming alloys. Less studied are strategies for optimizing these additions for developing a high‐performance, wrought FeCrAl alloy with maximum oxidation‐limited component life. Results from the literature are summarized regarding potential improvements. One promising strategy is the addition of two reactive elements, such as yttrium and hafnium, which has been effective in commercial and laboratory nickel‐based alloys and appears to impart the expected benefits, such as reducing the scale growth rate while minimizing detrimental effects, such as the formation of reactive element‐rich oxides in the scale and internal oxidation. Although there are promising data, the long‐term studies are not yet complete, and it is difficult to predict if “co‐doped” FeCrAl alloys will produce superior oxidation‐limited lifetimes in high‐temperature environments.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optimization of Reactive‐Element Additions to Improve Oxidation Performance of Alumina‐Forming Alloys

Pint¹

2003

Journal of the American Ceramic Society

250

View full text Add to dashboard Cite

show abstract

“…At high temperatures FeCrAl alloys, such as Kanthal AF, form a protective ␣-Al 2 O 3 scale that provides excellent oxidation resistance. While most of the research performed on these materials concerns temperatures above 1000°C, [1][2][3][4] they are often used at lower temperatures. Thus, FeCrAl materials are used as carrier materials for catalytic converters where the temperature is below 800°C.…”

mentioning

confidence: 99%

Microstructural Investigation of the Initial Oxidation of the FeCrAlRE Alloy Kanthal AF in Dry and Wet O[sub 2] at 600 and 800°C

Canovic¹,

Engkvist

Liu³

et al. 2010

J. Electrochem. Soc.

View full text Add to dashboard Cite

The FeCrAlRE (where RE is reactive element) alloy Kanthal AF was exposed isothermally at 600 and 800°C for 72 h in dry normalO2 and in normalO2 with 10 vol % normalH2O . The mass gains were 3–5 times higher at the higher temperature. The presence of water vapor increased the oxidation rate at 800°C , while no significant effect was observed at 600°C . A thin two-layered oxide formed at 600°C : an outer (Fe,Cr)2normalO3 corundum-type oxide, containing some Al, and an inner, probably amorphous, Al-rich oxide. At 800°C a two-layered oxide formed in both environments. The inner layer consisted of inward grown α-Al2normalO3 . In dry normalO2 the originally formed outward grown γ-Al2normalO3 had transformed to α-Al2normalO3 after 72 h. Water vapor stabilized the outward grown γ-Al2normalO3 and hence no transformation occurred after 72 h in humid environment. RE-rich oxide particles with varying composition (Y, Zr, and Ti) were distributed in the base oxide at both temperatures and in both environments. The RE-rich particles were separated from the alloy substrate by a layer of Al-rich oxide. At 800°C the Y-rich RE particles were surrounded by thick oxide patches in both dry and humid normalO2 .

show abstract

“…Substantial progress in understanding of the oxidation and degradation of 'alumina formers' achieved recently results from taking into account a variety of factors which affect their behaviour under service conditions. The following factors were considered : (i) stresses and strains, as described earlier; (ii) presence of additions and impurities [4,24,[32][33][34][35][36]; (iii) effect of sample geometry and shape, including its thickness [6,[37][38][39]; (iv) influence of reaction conditions under both, isothermal and thermal cyclic regimes [40][41][42]. Despite of the substantial progress achieved recently, the substrate-related effects still need to be studied more thoroughly in order to include them into proposed models.…”

Section: Modeling Of the Oxidation And Degradation Of 'Alumina Former...mentioning

confidence: 99%

Defect-Diffusion-Stress Relationships in Modeling the Oxidation and Degradation Processes of Alumina Formers: A Brief Survey

Jedliński

2005

DDF

View full text Add to dashboard Cite

In the modeling of the oxidation and degradation processes of the superior metallic materials in terms of the high temperature oxidation resistance, being the so-called alumina formers, the matter transport only via grain boundaries of α-Al2O3 is usually taken into account. This paper indicates that such an approach needs to be re-visited. It is pointed out that the following factors should be taken into account (i) diffusion via point defects in the unstable alumina polymorphs (γ, δ, θ) which grow during the early oxidation stages; (ii) dislocation-related processes; (iii) formation of the oxide in three-dimensional defects, being the cracks in the oxide layer; (iv) outward oxide growth resulting from the formation of the new oxide within the existing layer. The mentioned above effects as well as the other ones, related to the interfacial and stress-induced processes are illustrated and discussed. It is pointed out that alumina formers constitute a wide group of materials and several categories should be distinguished among them with respect to their composition and production route on one hand, and the oxidation and degradation mechanisms, on the other hand. It is shown that the comprehensive approach enables better and self-consistent modeling of the oxidation and degradation mechanisms of alumina formers.

show abstract

The Effect of Trace Amounts of Mg in FeCrAl Alloys on the Microstructure of the Protective Alumina Surface Scales

Cited by 8 publications

References 0 publications

Optimization of Reactive‐Element Additions to Improve Oxidation Performance of Alumina‐Forming Alloys

Optimization of Reactive‐Element Additions to Improve Oxidation Performance of Alumina‐Forming Alloys

Microstructural Investigation of the Initial Oxidation of the FeCrAlRE Alloy Kanthal AF in Dry and Wet O[sub 2] at 600 and 800°C

Defect-Diffusion-Stress Relationships in Modeling the Oxidation and Degradation Processes of Alumina Formers: A Brief Survey

Contact Info

Product

Resources

About