Diffusion in Oxides

Orman, James A. Van; Crispin, K. L.

doi:10.2138/rmg.2010.72.17

Cited by 170 publications

(83 citation statements)

References 178 publications

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“…Mn and Ti were reported by Aggarwal and Dieckmann [24]. The data were summarized by Van Orman and Crispin [18] Oxid Met (2017) 87:333-341 335 to lose its protective properties under more corrosive conditions, e.g. when water vapour, traces of alkali and/or chlorides are combined with O 2 , and in low oxygen activity environments containing water vapour, see, e.g.…”

Section: Resultsmentioning

confidence: 96%

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High-Temperature Oxidation of FeCr(Ni) Alloys: The Behaviour After Breakaway

Jonsson

Larsson²,

Karlsson

et al. 2017

Oxid Met

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The oxidation of an austenitic FeCr(Ni) steel at 600°C in H 2 O ? KCl ? O 2 /H 2 ? H 2 O ? Ar environments is studied up to 168 h. The oxidation behaviour after ''breakaway'' is investigated by microstructural investigations, and thermodynamic calculations (Thermo-Calc) on the FeCr(Ni)-O system are used to interpret the results. The characteristic ''breakaway'' scale morphology exhibits an outward-growing iron oxide and a bottom layer consisting of inward-growing spinel oxide and reaction zones containing Cr-rich oxide precipitates and Cr-depleted metal. The equilibrium calculations show that a miscibility gap appears in the FeCr spinel oxide below 665°C influencing the microstructure of the inward-growing scale. Equilibrium calculations on the FeCrNi-O system show that Ni is not expected to enter the spinel oxide in low oxygen activity conditions, in accordance with observations.

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Section: Resultsmentioning

confidence: 96%

“…in the spinel phase. shows the plot of the diffusivities of several cations in magnetite against oxygen activity at 1200°C, (adapted after Van Orman and Crispin [18] ) are expected to diffuse relatively rapidly towards the gas/scale interface during oxidation while the cations belonging to the latter group (i.e. Cr 3? )…”

Section: Fecr-o Systemmentioning

confidence: 99%

High-Temperature Oxidation of FeCr(Ni) Alloys: The Behaviour After Breakaway

Jonsson

Larsson²,

Karlsson

et al. 2017

Oxid Met

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“…This phenomenon can be explained in terms of the diffusivity of the Fe and Cr in TiO 2 . Fe has a relatively high diffusivity in rutile TiO 2 compared to other metals [33] and is detected in all of the 6 µm coatings, but at concentration less than 1.5 atomic percent. The Fe concentration increases with deposition temperature (shown in Figure 8).…”

Section: Methodsmentioning

confidence: 95%

Titania‐based photocatalytic coatings on stainless steel hospital fixtures

Krumdieck

Lee³

et al. 2015

Phys. Status Solidi C

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A scaled-up pulsed-pressure MOCVD system was used to deposit TiO 2 coatings from tetra-isopropoxide precursor solution on stainless steel substrates and on 3-D objects. The objective of the work is the production of antimicrobial coatings for handles in health care facilities. Antimicrobial coatings are sought to manage the transmission of hospital acquired infections (HAI's), which are reported to cost around one million pounds per annum in the UK alone. Titania is a promising material for this application due to the photocatalytic production of reactive oxygen species that are crucial for the destruction of organic pathogens.TiO 2 coatings of 0.2 to 13 µm thickness were deposited at temperatures between 375 o C and 475 o C. The crystallite size and photocatalytic activity are influenced by deposition temperature. No dependence of stoichiometry on the deposition temperature has been observed. The films on stainless steel exhibit reasonably good photocatalytic performance. The photocatalytic performance and the stoichiometry improve with the film thickness. A three dimensional object (door handle) was coated with good conformity. The reactor scale-up for coating production on door handles is proposed for future wear and hygiene performance testing.

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“…The error caused by temperature uncertainty is thus small (less than a factor of 2) because the temperature of concern is near this minimum value. The diffusion coefficient of Mg in magnetite has rarely been reported and has not been cited even in the most comprehensive review papers (e.g., Costa et al 2008;Van Orman and Crispin 2010). Only experiments by Semberg et al (2011) Semberg et al (2011).…”

Section: Diffusion Coefficients In Magnetitementioning

confidence: 99%

“…Recently, Mg in plagioclase has been used to provide time scales of days to years (e.g., Costa et al 2003Costa et al , 2008Druitt et al 2012;Ruprecht and Cooper 2012). Magnetite phenocrysts are particularly useful in silicic magma systems for detecting the processes within days to months before eruption (e.g., Nakamura 1996; Devine et al 2003;Chertkoff and Gardner 2004;Tomiya and Takahashi 2005) because of their rapid diffusion (Van Orman and Crispin 2010) and common occurrence in various types of magma. Titanium diffusion profiles of magnetite have often been analyzed to discuss time scales from magma mixing to eruption.…”

Section: Introductionmentioning

confidence: 99%

Short time scales of magma-mixing processes prior to the 2011 eruption of Shinmoedake volcano, Kirishima volcanic group, Japan

et al. 2013

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We estimated time scales of magma-mixing processes just prior to the 2011 sub-Plinian eruptions of Shinmoedake volcano to investigate the mechanisms of the triggering processes of these eruptions. The sequence of these eruptions serves as an ideal example to investigate eruption mechanisms because the available geophysical and petrological observations can be combined for interpretation of magmatic processes. The eruptive products were mainly phenocryst-rich (28 vol%) andesitic pumice (SiO 2 57 wt%) with a small amount of more silicic pumice (SiO 2 62-63 wt%) and banded pumice. These pumices were formed by mixing of low-temperature mushy silicic magma (dacite) and high-temperature mafic magma (basalt or basaltic andesite). We calculated the time scales on the basis of zoning analysis of magnetite phenocrysts and diffusion calculations, and we compared the derived time scales with those of volcanic inflation/deflation observations. The magnetite data revealed that a significant mixing process (mixing I) occurred 0.4 to 3 days before the eruptions (preeruptive mixing) and likely triggered the eruptions. This mixing process was not accompanied by significant crustal deformation, indicating that the process was not accompanied by a significant change in volume of the magma chamber. We propose magmatic overturn or melt accumulation within the magma chamber as a possible process. A subordinate mixing process (mixing II) also occurred only several hours before the eruptions, likely during magma ascent (syn-eruptive mixing). However, we interpret mafic injection to have begun more than several tens of days prior to mixing I, likely occurring with the beginning of the inflation (December 2009). The injection did not instantaneously cause an eruption but could have resulted in stable stratified magma layers to form a hybrid andesitic magma (mobile layer). This hybrid andesite then formed the main eruptive component of the 2011 eruptions of Shinmoedake.

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Diffusion in Oxides

Cited by 170 publications

References 178 publications

High-Temperature Oxidation of FeCr(Ni) Alloys: The Behaviour After Breakaway

High-Temperature Oxidation of FeCr(Ni) Alloys: The Behaviour After Breakaway

Titania‐based photocatalytic coatings on stainless steel hospital fixtures

Short time scales of magma-mixing processes prior to the 2011 eruption of Shinmoedake volcano, Kirishima volcanic group, Japan

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