Void Formation in the Growing Scale Induced by the Divergence of the Diffusive Ionic Flux in High Temperature Oxidation of Metals

Maruyama, Toru; Ueda, Mitsutoshi; Kawamura, Kazutaka

doi:10.4028/www.scientific.net/ddf.289-292.1

Cited by 10 publications

(5 citation statements)

References 7 publications

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“…This is because magnetite's spinel structure exhibits ferrimagnetism which enhances its magnetic and electrical properties compared to hematite's alpha-corundum crystal structure. Other than that, void percentage results from this paper have been compared to previous work done by Akiba et al [36], Maruyama et al [14], Ueda et al [19] and Kaderi et al [12].…”

Section: Discussionmentioning

confidence: 79%

“…Figure 17 shows a summary of work done on volume fraction of voids on the outermost scale of the sample with respect to oxygen partial pressure, . A study on void at formation at magnetite scale conducted by Ueda et al [19] and Maruyama et al [14] showed a very small range of void formed in the range of 0.05 to 0.06. Note that that these two studies were conducted in a controlled environment.…”

Section: Volume Fraction Of Voids In Oxide Scalementioning

confidence: 98%

“…al. [14] wherein he claimed that void formation during high temperature oxidation was closely related to the divergence of ionic uxes.…”

Section: P Omentioning

confidence: 99%

“…al. [14] wherein he claimed that void formation during high temperature oxidation was closely related to the divergence of ionic uxes. Therefore, it is possible to investigate the oxidation of metal surfaces in the presence of an oxidising agent by combining Fick's rst law with Wagner's oxidation kinetics where the calculations have been discussed by Noguchi and Yakuwa [15].…”

Section: Introductionmentioning

confidence: 99%

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Voltage-Induced Void Formation in High-Temperature Oxide Scales of Boiler Tubes

Rosdin,

Bakar,

Hamid

et al. 2024

Preprint

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The formation of voids in the oxide scale during high temperature oxidation is one of critical issues that leads to poor oxide scale adherence, fouling, spalling and materials loss, which affect substrate’s performance. Visual inspection is currently the sole way to detect corrosion process at high temperature environment. At room temperature, under the standard condition, cathodic protection has been successfully employed to monitor and control the corrosion. Understanding the development of voids in oxide scale is crucial to develop mitigation strategies and predictive maintenance. Thus, this study was intended to serve as a preliminary step to emulate the cathodic protection technique at high temperature. By polarizing the sample, it is postulated that it may affects the diffusivity of cation/anion in oxide scale, which is the rate determining step of the oxidation process. Ueda et al and Maruyama et al has shown that the difference in flux, or chemical potential of the oxygen species is the sole factor for the formation of void in oxide scale in controlled environment. In this study, the amount of voids present was measure directly on T91 alloys exposed at 823 K under various induced voltageT91 alloy which consists of Fe-9%Cr was externally induced with voltages of 0V, 50V and 300V for 43.2 ks, 259.2 ks and 432 ks at 923 K in air (\({P}_{{O}_{2}}\)) = 0.21 atm = 2.1 × 104 Pa). The presence of oxide layers was analysed using X-Ray Diffraction (XRD) and the void formed was inspected using Scanning Electron Microscopy (SEM). XRD results reveal that peaks of Fe2O3, Fe3O4, FeCr2O3 and Cr2O3 were formed on all sample. The parabolic rate constant, Kp was calculated as 3.83 × 10–14 m2/s, 2.17 × 10–14 m2/s and 9.25 × 10–14 m2/s respectively, verifying that the reaction occurred was a solid state diffusion. Changes in Kp at different induced voltages is clear evidence that the diffusivity was altered by external electrical potential. It was observed that the overall void formation decreased by 17%. Apparently, inducing voltage onto T91 alloy effects the ionic diffusivity and changes the void formation. Conversely, it may be used to promote diffusivity of more inert species such as Cr to form protective layer at early stage of oxidation.

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Section: Discussionmentioning

confidence: 79%

Section: Volume Fraction Of Voids In Oxide Scalementioning

confidence: 98%

“…al. [14] wherein he claimed that void formation during high temperature oxidation was closely related to the divergence of ionic uxes.…”

Section: P Omentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Voltage-Induced Void Formation in High-Temperature Oxide Scales of Boiler Tubes

Rosdin,

Bakar,

Hamid

et al. 2024

Preprint

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show abstract

“…The formation of void, gap and pore are common phenomena in Fe 3 O 4 scale of Fe 9-10%Cr steels. It has been reported that higher quantity of void formed in the Fe 3 O 4 scale grown on Fe substrate exposed in higher PO 2 atmosphere (PO 2 = 1.6 × 10 -11 Pa) equivalent to H 2 /H 2 O ratio of 7 × 10 -5 [18,21] . Figure 4 is a compilation of quantitative studies on volume fraction of voids with respect to oxygen partial pressure, PO 2 .…”

Section: Void Formation In Oxide Scalementioning

confidence: 99%

Studies on Initial Stage of High Temperature Oxidation of Fe - 9 to 12%Cr Alloys in Water Vapour Environment

Kaderi

Ani

Herman

et al. 2012

AMR

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Fe - 9 to 12%Cr alloys are a material for the thick sections boiler components and steam lines of a power plant. The role Fe - 9 to 12%Cr alloys is becoming more prominent in the development of a new generation of Ultra-Supercritical (USC) Power Plant due to the target operating temperature is reaching 620 °C (893 K), in 100% steam condition as well as pressure in excess of 300 bar (30 × 106 Pa). In such condition, the integrity of Fe - 9 to 12%Cr alloys relies on the oxide scale formed during the time of exposure. However due to the high temperature and water vapor condition, it is a well known fact that, the formation of oxide scale is accelerated thus depleting the structural integrity of the Fe - 9 to 12%Cr alloys over the time. Studies show that not only the formation of protective oxide scale was suppressed but the formation of non-protective oxide scale was accelerated instead. Decades of studies done by various groups around the globe has yet to have consensual on the exact mechanism of this phenomenon. Initial stage oxidation of these alloys plays great roles in hope to understand the formation of oxide scale in water vapor condition at high temperature. This paper reviews previous research works to understand the initial stage oxidation of Fe - 9 to 12%Cr alloys at high temperature in water vapor condition.

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Corrosion of 9Cr Steel in CO2 at Intermediate Temperature I: Mechanism of Void-Induced Duplex Oxide Formation

et al. 2011

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Under CO 2 exposure at an intermediate temperature, typically 550°C, 9Cr-1Mo steel forms a duplex oxide scale made of an outer magnetite layer and an almost-as-thick inner Fe-Cr rich spinel oxide layer. It is proposed that the inner Fe-Cr spinel layer grows according to a mechanism involving void formation at the oxide/ metal interface. The driving force for pore formation is the outward magnetite growth: iron vacancies are injected at the oxide/metal interface then condense into voids. The fresh metallic surface made available is then oxidized by CO 2 , which diffuses fast through the scale. The physical aspects, the integrity and the nature of the scale are shown to be very dependent on the oxygen potential existing in the environment.

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Void Formation in the Growing Scale Induced by the Divergence of the Diffusive Ionic Flux in High Temperature Oxidation of Metals

Cited by 10 publications

References 7 publications

Voltage-Induced Void Formation in High-Temperature Oxide Scales of Boiler Tubes

Voltage-Induced Void Formation in High-Temperature Oxide Scales of Boiler Tubes

Studies on Initial Stage of High Temperature Oxidation of Fe - 9 to 12%Cr Alloys in Water Vapour Environment

Corrosion of 9Cr Steel in CO2 at Intermediate Temperature I: Mechanism of Void-Induced Duplex Oxide Formation

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