Die Oxydationsgeschwindigkeit von Nickel bei kleinen Zusätzen von Chrom und Mangan. Beitrag zur Theorie des Anlaufvorganges.

Wagner, Carl; Zimens, Karl-Erik; Sillén, Lars Gunnar; Linnasalmi, Annikki; Laukkanen, Pentti

doi:10.3891/acta.chem.scand.01-0547

Cited by 73 publications

(28 citation statements)

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“…[35][36][37] Thus, the increased scaling kinetics on the NiCrCo alloy must be largely attributed to cobalt oxidation and to the change in the boundary conditions at the alloy/scale interface for scale growth. These effects outweighed any beneficial doping effect of Co in Cr 2 O 3 .…”

Section: Discussionmentioning

confidence: 99%

Effects of Silicon on the Oxidation Behavior of Ni-Base Chromia-Forming Alloys

Gleeson

2006

Oxid Met

117

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This paper compares and analyzes the oxidation behavior of Ni-base alloyswith and without about 2.7 wt.% Si addition. The Ni-base alloys studied were of two types: cast model alloys or wrought commercial alloys. Oxidation testing was conducted at 1000 • C in still air. The specific aspects studied were scale spallation resistance, nature by which the silicon oxidized, and the influence of silicon on the subsurface depletion behavior of chromium. From oxidation results of the cast model alloys, Si addition was found to improve oxidation resistance by forming a continuous SiO 2 layer at the alloy/scale interface, which resulted in decreased oxidation kinetics. The cast alloys with Si addition also showed larger average effective interdiffusion coefficients of chromium compared to the cast alloys without Si addition. As a consequence, the Si addition assisted in the establishment and re-formation of a chromia scale during oxidation. In the case of the wrought commercial alloys, a discontinuous distribution of SiO 2 precipitates in the vicinity of the alloy/scale interface was found to be beneficial to cyclic oxidation resistance.KEY WORDS: high temperature oxidation; silicon effect; chromia-former; Ni-base alloy; chromium depletion and interdiffusion behavior.

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Section: Discussionmentioning

confidence: 99%

Effects of Silicon on the Oxidation Behavior of Ni-Base Chromia-Forming Alloys

Gleeson

2006

Oxid Met

117

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“…Previous studies on Ni-Cr and Co-Cr binary alloys have determined that a concentration of Cr in excess of 10 wt.% is required to allow the formation of a protective chromia layer [6]. The parabolic growth rate of this oxide has been shown to decrease as the concentration of Cr increases, reaching a minimum around 20 -25 wt.% [15,16]. The presence of Al in the alloy has also been shown to improve the oxidation characteristics of chromia scale forming alloys by increasing the Cr activity [17].…”

Section: Introductionmentioning

confidence: 99%

The Oxidation Behaviour of Alloys Based on the Ni–Co–Al–Ti–Cr System

et al. 2015

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The isothermal oxidation behaviour of a series of quinary Ni-Co-AlTi-Cr alloys were studied at 800°C. Alloys with higher Cr concentrations exhibited lower mass gain after 100-h exposure, as did the alloys richest in Ni and Al for a given Cr concentration. Extensive internal oxidation and nitridation was also observed in all alloys, except those containing the highest concentrations of Ni and Al. All alloys studied generated continuous chromium oxide layers, beneath which alumina particles were observed. Compositional analysis of the subscales identified shallower Cr concentration gradients in alloys containing equiatomic levels of Ni and Co, suggesting increased availability of Cr in the alloy. Thermodynamic calculations confirmed that these alloys contained higher concentrations of Cr in their c matrices as a result of a combination of both the elemental partitioning behaviour and the increased mole fraction of c 0 precipitates forming in the alloy.

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“…A small amount of Ta 2 O 5 and Ta-containing spinels dispersed among the Cr 2 O 3 , playing the role of dopant. When Cr 2 O 3 is doped with Ta 2 O 5 , higher valence Ta ions, Ta 5+ , will increase the concentration of cation vacancies in Cr 2 O 3 scale and further accelerate the growth rate of Cr 2 O 3 [10,22]:…”

Section: Interaction Of Ta and Crmentioning

confidence: 99%

Investigation on Optimal Ta/Cr Ratio of a Single Crystal Ni-Base Superalloy in View of the Isothermal Oxidation Behavior

et al. 2021

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The relative content of strengthening element tantalum (Ta) and oxidation-resistant element chromium (Cr) is an essential value for superalloys to obtain an excellent combination of oxidation resistance and mechanical properties. In the present paper, the isothermal oxidation behavior of several single crystal Ni-base superalloys with different Ta/Cr (wt. %, similarly hereinafter) ratios at 1000 °C in static air has been systematically investigated to explore the optimal Ta/Cr for excellent oxidation resistance. A detailed microstructure study using X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) and an electro-probe microanalyzer (EPMA) was performed to reveal the oxidation products and mechanisms. For all alloys, a three-layer structured scale consisting of an outer (Cr, Al, Ti, Ni, Ta)-O layer, an inner Al2O3 layer and an inner nitride layer was formed. As Ta/Cr increased, the amounts of Ta-containing products, cracks, holes and inner nitride increased. Meanwhile, the completeness of the Al2O3 layer got worse. It was shown that if Ta/Cr ≤ 0.5, Ta increased the growth rate of Cr2O3 via the doping effect induced by Ta cations. If Ta/Cr > 0.5, Ta reduced the completeness of Cr2O3 through competitive growth of Ta2O5 and Cr2O3. A good oxidation performance can be expected with the value Ta/Cr ≤ 0.5.

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Die Oxydationsgeschwindigkeit von Nickel bei kleinen Zusätzen von Chrom und Mangan. Beitrag zur Theorie des Anlaufvorganges.

Cited by 73 publications

References 0 publications

Effects of Silicon on the Oxidation Behavior of Ni-Base Chromia-Forming Alloys

Effects of Silicon on the Oxidation Behavior of Ni-Base Chromia-Forming Alloys

The Oxidation Behaviour of Alloys Based on the Ni–Co–Al–Ti–Cr System

Investigation on Optimal Ta/Cr Ratio of a Single Crystal Ni-Base Superalloy in View of the Isothermal Oxidation Behavior

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