Protective and non-protective scale formation of NiCr alloys in water vapour containing high- and low-pO2 gases

Essuman, E.; Meier, G. H.; Żurek, J.; Hänsel, M.; Norby, Truls; Singheiser, L.; Quadakkers, W. J.

doi:10.1016/j.corsci.2008.03.001

Cited by 89 publications

(47 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…8 Oxidation resistance of these alloys depends strongly on the Cr concentration and it has been found that addition of <8 wt.% leads to an increase in oxidation rate while alloying with 10-20 wt.% Cr results in reduced oxidation rates due to the formation of a continuous chromium oxide layer protects the material from further degradation. [9][10][11] Despite the technological relevance, the initial reaction steps in the oxidation of the alloy are not well understood. A facile route for fabrication of high quality NiCr alloy thin films would open up a path for the atomic scale study of oxidation as a function of Cr composition and prevents the need for cost intensive fabrication and cleaning of single crystals of different compositions.…”

Section: Introductionmentioning

confidence: 99%

Growth of Ni and Ni-Cr alloy thin films on MgO(001): Effect of alloy composition on surface morphology

Ramalingam

Reinke

2016

Journal of Applied Physics

View full text Add to dashboard Cite

The effects of substrate treatment, growth temperature and composition on the surface morphology of Ni-Cr thin films grown on MgO(001) are studied by scanning tunneling microscopy (STM) and atomic force microscopy (AFM). We demonstrate that a combination of acid-etched substrates and high temperature deposition (400 °C) will result in smooth films with well-defined terraces (up to 30 nm wide) that are suitable for the study of progression of chemical reactions on the surface. Two different treatments are used to prepare the MgO substrates for deposition and they introduce characteristic differences in film surface morphology. Thin films that are grown on the phosphoric acid-treated substrates present reduced nucleation density during the initial stages of film growth which results in long and wide terraces. Due to the ≈16% lattice mismatch in the Ni(001)/MgO(001) system, film growth at 400 °C yields discontinuous films and a twostep growth process is necessary to obtain a continuous layer. Ni films are deposited at 100 °C and subjected to a post-growth anneal at 300 °C for 2 hours to obtain a smoother surface. The addition of just 5 wt.% Cr drastically changes the film growth processes and yields continuous films at 400 °C without de-wetting in contrast to pure Ni films. With increasing Cr content, the films become progressively smoother with wider terraces.Ni5Cr alloy thin films have an rms surface roughness of 3.63±0.75 nm while Ni33Cr thin film is smoother with an rms roughness of only 0.29±0.13 nm. The changes in film growth initiated by alloying with Cr are due to changes in the interfacial chemistry which 2 favorably alters the initial adsorption of the metal atoms on MgO surface and suggests a reduction of the Ehrlich-Schwoebel barrier. The growth of smooth Ni-Cr thin films with a well-defined surface structure opens up a new pathway for a wide range of surface science studies related to alloy performance.

show abstract

Section: Introductionmentioning

confidence: 99%

Growth of Ni and Ni-Cr alloy thin films on MgO(001): Effect of alloy composition on surface morphology

Ramalingam

Reinke

2016

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…Water vapour effects have already been described in the literature [18][19][20][21]. Several studies were conducted on chromia forming alloys [22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Influence of water vapour on 316L oxidation at high temperature - in situ X-Ray diffraction

Buscail¹,

Rolland²,

Perrier³

2015

Ann. Chim. Sci. Mat.

View full text Add to dashboard Cite

-Water vapour mixed with air (10 vol.% H 2 O) has little effect on the AISI 316L stainless steel oxidation under isothermal conditions at 800 and 900 °C. The oxide scale is composed of Cr 2 O 3 and Mn 1.5 Cr 1.5 O 4 located at the external interface. Results show that the presence of water lowers the specimen's mass gain. At 1000 °C, the effect of water vapour on the scale structure is deleterious. In situ X-ray diffraction permits to show that the breakaway is due to iron oxidation starting after about 30 hours. This leads to an external Fe 2 O 3 scale growth and an internal multilayered FeCr 2 O 4 scale formation.

show abstract

“…The reason that the two types of gas systems were adopted for environment of the experiments is to evaluate water molecule effect on characteristics of oxide (7) and cracking susceptibility of Ni-Cr alloys. Figure 1 shows target oxygen partial pressure (P O2 ) in the experiments.…”

Section: Oxidation Experimentsmentioning

confidence: 99%

Oxidation Behavior and Cracking Susceptibility of Ni-Cr Alloys in Dry Steam and Inert Gas under Extremely-Low Oxygen Partial Pressure

Abe

Kenmoku

Endo

et al. 2010

JMMP

View full text Add to dashboard Cite

In order to investigate oxidation behavior and cracking susceptibility of the Ni-Cr alloys under extremely-low oxygen partial pressure, three Ni-Cr alloys (Ni-14Cr, Ni-22Cr and Ni-30Cr) were used as plate specimen and reverse U-bend specimen for oxidation experiments for 750 hours at 400 o C in two kinds of gas system (inert gas and dry steam) under various oxygen potential (Ni stable, Ni/NiO equilibrium and NiO stable). The Ni-Cr alloys cracked along grain boundary both in inert gas system (with trace O 2 , without H 2 O) and in hydrogenated steam. In the inert gas system, the cracking susceptibility was confirmed in near NiO stable condition. On the other hand, no crack was found in near Ni stable condition. In the dry steam system, the cracking susceptibility was confirmed in near Ni/NiO equilibrium. In contrast, no crack was found in near NiO stable condition. The cracking susceptibility was confirmed in near Ni/NiO equilibrium in hydrogenated steam as contrasted with higher oxygen potential in inert gas system. This result shows that potential range for the cracking susceptibility seemed to be different between the two kinds of gas system. Cracking severity was highest for Ni-14Cr and lowest for Ni-30Cr both in inert gas and steam; however, even Ni-30Cr was not immune to intergranular cracking in steam near Ni/NiO equilibrium.

show abstract

Protective and non-protective scale formation of NiCr alloys in water vapour containing high- and low-pO2 gases

Cited by 89 publications

References 19 publications

Growth of Ni and Ni-Cr alloy thin films on MgO(001): Effect of alloy composition on surface morphology

Growth of Ni and Ni-Cr alloy thin films on MgO(001): Effect of alloy composition on surface morphology

Influence of water vapour on 316L oxidation at high temperature - in situ X-Ray diffraction

Oxidation Behavior and Cracking Susceptibility of Ni-Cr Alloys in Dry Steam and Inert Gas under Extremely-Low Oxygen Partial Pressure

Contact Info

Product

Resources

About