Anion Diffusion in α‐Cr<sub>2</sub>O<sub>3</sub>

Hagel, W. C.

doi:10.1111/j.1151-2916.1965.tb11802.x

Cited by 124 publications

(37 citation statements)

References 14 publications

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“…4 within the coordinates Al/~ ~ /~ products !inearizationo This relationship is inherent in many refractoried which sinter through volume diffusion [6]. 6 demonstrate the reasonable agreement of our results for Poa = 10-I~ Pa, both with the coefficient of self-diffusion of the oxygen ion into Cr2Oa [9], and also with the energy of activation of the process (~ 400 kJ/mole). 4 to calculate the apparent coefficient of diffusion Dap p from the equation obtained for the simplest model of a sintering sphere [7].…”

supporting

confidence: 83%

“…The authors of [ii] came to similar conclusions on the basis of the similarity of the diffusion coefficients measured by the radioisotope method [9] and the values of Dap p found from the experimental results for sintering Cr=03.…”

Section: Data Insupporting

confidence: 60%

“…A reduction in P02 from 10 -3 to 10 -7 Pa reinforces the sintering action of Ti02 in the range 1200-1400~ when it is added in amounts of both 5% and 20%. Relationship between the apparent coefficient of diffusion Dap p of Cr203 and inverse temperature: I) according to [8]; 2) according to Krivoruchko's data [12]; 3) according to [9]; 4) according to [ii]; 5-8) our data when po 2 equals 10 -I , 10 -4 , 10 -7 , and 10 -I~ Pa respectively. 1 shows that titanium dioxide aids the sintering of Cr203 at 1300~ in the whole PO range studied; it aids at 1400~ in the case of PO =~ 3Pa, while at 1500~ additional shrinkage on account of alloying does not excee~l% for all P02 values.…”

mentioning

confidence: 97%

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Sintering and recrystallization of chromium oxide

et al. 1983

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Investigations of the sintering of chromium oxide have shown that the most effective sintering additive is titanium dioxide, and the crucial factor in obtaining dense specimens is a reduction on the partial pressure of the oxygen P02 in the firing atmosphere [12,[1][2][3][4]. However, the linking of both conditions has been studied only at one temperature --in [1-4] for a single composition , and in [3] in a limited range of TiO= concentrations. In actual conditions the sintering of Cr203 occurs in a wide temperature range and POd range, created either in furnaces with a controlled atmosphere, or in the presence of carbon-containing agents. Therefore, to clarify the mechanism of chromium-oxide sintering and the differentiation of the properties of refractories, we need to obtain data on the combined influence of P02 and sintering additive in a rather wide temperature range. This paper gives the results of a study of the sintering of Cr20s without additives and with an addition of from 0.5 to 20% * Ti02 at 1200-1600~ in the range P02 = 2"104-10-6 Pa and recrystallization of the chromium oxide with an addition of 1% TiO= and MgO at 1450-1760~ in air, and in an atmosphere with a reduced oxygen concentration. The subject of the investigation consisted of powdered Cr=03 grade OKhM-I and Ti02 of chemical purity grade, the properties of which were given in [5]. The variable partial pressure of oxygen in the furnace and its measurement were provided with apparatus described previously [12]. The crystal size were determined by the section method, and the ceramic and strength factors of the specimens were measured with the standard methods. *Here and subsequently, molar proportions are used. so~~oo~c L. 1~oo'c , t 15oo~ ! 16oo~ ,o --~ 2.107 2or 1 s ]1o-' .3"!o ~ ,~-'~=----" 16~ I 3./0" I 9 lO-J I I 0 " ~ iO'~ I0 "s 0 4 8 f2 16 20 ~ 8 12 I6 20 # 8 f2 16 204 8 12 f6 20 4 8 12 1620Content of riOz, %

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supporting

confidence: 83%

Section: Data Insupporting

confidence: 60%

mentioning

confidence: 97%

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Sintering and recrystallization of chromium oxide

et al. 1983

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“…Der Diffusionskoeffizient von O"-Ionen in CreOs fur 1300'K mit D = 1.6 . 10-16 ist dagegen erheblich geringer(7…”

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“…= 1.6 . 10-16 ist dagegen erheblich geringer(7). Der Schwefel wird also schneller ins Chromoxid wandern als02 -und sich unterhalb der Oxidschicht rnit Chrommetall zu Sulfid umsetzen.…”

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Die Rolle der Alkalisulfate bei der Hochtemperaturkorrosion. Teil III: Modellversuche zur Sulfidbildung unter Luftausschluß

Fechner

Umland

1973

Materials & Corrosion

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Die mit verschiedenen Metallen ( Ni, Cr, Co, Ti, NiCr 80 20, NiCrTi 75 20 2,5) in geschmolzenem Natriumsulfat in Argonatmosphäre bei 900 °C durchgeführten Versuche zeigen die ausschlaggebende Rolle des Sauerstoffpartialdrucks an der Grenzfläche Metall/Zunder. Nickelsulfid entsteht nur bei sehr niedrigen Sauerstoffpartialdrucken. Um die Bildung von Nickelsulfiden — insbesondere des äußerst gefährlichen Ni3S2 — zu verhindern, muß man darauf achten, daß der Sauerstoffpartialdruck an der Grenzfläche verhältnismäßig hoch bleibt; diese Bedingung wird erfüllt, wenn die Sulfatschicht auf dem Metall verhältnismäßig dünn ist oder wenn man diese Schicht durch Zusatz indifferenter Stoffe etwas auflockert.

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Resolving Diverse Oxygen Transport Pathways Across Sr‐Doped Lanthanum Ferrite and Metal‐Perovskite Heterostructures

Taylor

Yano

Sassi

et al. 2023

Adv Materials Inter

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Perovskite structured transition metal oxides are important technological materials for catalysis and solid oxide fuel cell applications. Their functionality often depends on oxygen diffusivity and mobility through complex oxide heterostructures, which can be significantly impacted by structural and chemical modifications, such as doping. Further, when utilized within electrochemical cells, interfacial reactions with other components (e.g., Ni‐ and Cr‐based alloy electrodes and interconnects) can influence the perovskite's reactivity and ion transport, leading to complex dependencies that are difficult to control in real‐world environments. Here, this work uses isotopic tracers and atom probe tomography to directly visualize oxygen diffusion and transport pathways across perovskite and metal‐perovskite heterostructures, that is, (Ni‐Cr coated) Sr‐doped lanthanum ferrite (La0.5Sr0.5FeO3; LSFO). Annealing in 18O2(g) results in elemental and isotopic redistributions through oxygen exchange (OE) in the LSFO while Ni‐Cr undergoes oxidation via multiple mechanisms and transport pathways. Complementary density functional theory calculations at experimental conditions provide rationale for OE reaction mechanisms and reveal a complex interplay of different thermodynamic and kinetic drivers. These results shed light on the fundamental coupling of defects and oxygen transport in an important class of catalytic materials.

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Anion Diffusion in α‐Cr₂O₃

Cited by 124 publications

References 14 publications

Sintering and recrystallization of chromium oxide

Sintering and recrystallization of chromium oxide

Die Rolle der Alkalisulfate bei der Hochtemperaturkorrosion. Teil III: Modellversuche zur Sulfidbildung unter Luftausschluß

Resolving Diverse Oxygen Transport Pathways Across Sr‐Doped Lanthanum Ferrite and Metal‐Perovskite Heterostructures

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Anion Diffusion in α‐Cr2O3

Cited by 124 publications

References 14 publications

Sintering and recrystallization of chromium oxide

Sintering and recrystallization of chromium oxide

Die Rolle der Alkalisulfate bei der Hochtemperaturkorrosion. Teil III: Modellversuche zur Sulfidbildung unter Luftausschluß

Resolving Diverse Oxygen Transport Pathways Across Sr‐Doped Lanthanum Ferrite and Metal‐Perovskite Heterostructures

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Anion Diffusion in α‐Cr₂O₃