Mechanism of Carbon Diffusion in the Iron Sheet During Gas–Solid Decarburization

Hong, Lukuo; Cheng, Rong; Ai, Liqun; Sun, Caijiao

doi:10.1007/s12666-018-1484-8

Cited by 10 publications

(5 citation statements)

References 12 publications

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“…It is the reverse process of carburization in which material was heated in air at an austenizing temperature. As a result, oxygen molecules react with the surface's carbon atoms and produces carbon monoxide (CO) and carbon dioxide (CO 2 ) gas which then dissolve into atmosphere [46]. Both steels were heated at the same temperature under a similar environment, but due to alloying difference of carbon within the chemical composition, SUS 430 showed less diffusion of carbon as compared to Crofer 22 APU.…”

Section: Resultsmentioning

confidence: 99%

Mitigation of Chromium Poisoning of Ferritic Interconnect from Annealed Spinel of CuFe2O4

Hassan

Mamat

2020

Processes

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Low-temperature solid oxide fuel cells permit the possibility of metallic interconnects over conventional ceramic interconnects. Among various metallic interconnects, the ferritic interconnects are the most promising. However, chromium poisoning in them adversely affects their performance. To resolve this issue, various coatings and pretreatment methods have been studied. Herein, this article encloses the coating of CuFe2O4 spinel over two prominent ferritic interconnects (Crofer 22 APU and SUS 430). The CuFe2O4 spinel layer coating has been developed by the dip-coating of both samples in CuFe2O4 slurry, followed by heat treatment at 800 °C in a reducing environment (5% hydrogen and 95% nitrogen). Additionally, both samples were annealed to further enhance their spinel coating structure. The morphological and crystallinity analysis confirmed that the spinel coating formed multiple layers of protection while annealing further reduced the thickness and improved the densities. Moreover, the area-specific resistance (ASR) and weight gain rate (WGR) of both samples before and after annealing was calculated using mathematical modeling, which matches with the experimental data. It has been noted that CuFe2O4 spinel coating improved the ASR and WGR of both samples which were further improved after annealing. This research reveals that the CuFe2O4 spinel is the promising protective layer for ferritic interconnects and annealing is the better processing technique for achieving the preferred properties.

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Section: Resultsmentioning

confidence: 99%

Mitigation of Chromium Poisoning of Ferritic Interconnect from Annealed Spinel of CuFe2O4

Hassan

Mamat

2020

Processes

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“…Our team previously reported basic studies in two atmospheres, H 2 O-H 2 and CO-CO 2 [38][39][40][41][42], with a maximum decarburisation temperature of 1413 K. In this paper, the decarburisation effect under two atmospheres is studied, and the difference in the decarburisation mechanism is analysed. Although there was a carbon concentration gradient in the steel plate during the decarburisation process, there were different structures and phase compositions.…”

Section: Introductionmentioning

confidence: 99%

Analysis of decarburisation mechanism of Fe-C alloy strip

Zhou

Hong

et al. 2023

Materials Science and Technology

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Comparative experiments on different decarburisation processes of Fe-C alloys in Ar-CO-CO2 and Ar-H2O-H2 atmospheres were carried out. The fundamental principles of carbon distribution, migration, and conversion are elucidated during decarburisation in both atmospheres. The completely decarburised layer of 2-mm-thick strip in Ar-CO-CO2 atmosphere appeared about 20 min later than the decarburisation in Ar-H2O-H2 atmosphere. Compared with the decarburisation in the Ar-H2O-H2 atmosphere, the carbon-rich phase dissolution zone is wider and the solid solution carbon content in the centre side is lower in the Ar-CO-CO2 atmosphere. The concentration gradient of solid solution carbon on the centre side of the interface of austenite zone in Ar-CO-CO2 atmosphere is smaller than that in the Ar-H2O-H2 atmosphere.

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“…Decarburization is a carbon-loss process in a material that occurs due to its exposure to oxidizing environments at elevated temperatures [ 1 ]. At high temperatures, the diffusion rate of carbon is so large that a significant amount of carbon loss may occur in regions adjacent to the surface [ 2 , 3 ]. Decarburization results in poor material properties, such as lower strength, poor wear resistance, and reduced fatigue life [ 4 , 5 , 6 ].…”

Section: Introductionmentioning

confidence: 99%

Decarburization of Wire-Arc Additively Manufactured ER70S-6 Steel

et al. 2023

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Decarburization is an unwanted carbon-loss phenomenon on the surfaces of a material when they are exposed to oxidizing environments at elevated temperatures. Decarburization of steels after heat treatment has been widely studied and reported. However, up to now, there has not been any systematic study on the decarburization of additively manufactured parts. Wire-arc additive manufacturing (WAAM) is an efficient additive manufacturing process for producing large engineering parts. As the parts produced by WAAM are usually large in size, the use of a vacuum environment to prevent decarburization is not always feasible. Therefore, there is a need to study the decarburization of WAAM-produced parts, especially after the heat treatment processes. This study investigated the decarburization of a WAAM-produced ER70S-6 steel using both the as-printed material and samples heat-treated at different temperatures (800 °C, 850 °C, 900 °C, and 950 °C) for different durations (30 min, 60 min, and 90 min). Furthermore, numerical simulation was carried out using Thermo-Calc computational software to predict the carbon concentration profiles of the steel during the heat treatment processes. Decarburization was found to occur not only in the heat-treated samples but also on the surfaces of the as-printed parts (despite the use of Ar for shielding). The decarburization depth was found to increase with an increase in heat treatment temperature or duration. The part heat-treated at the lowest temperature of 800 °C for merely 30 min was observed to have a large decarburization depth of about 200 μm. For the same heating duration of 30 min, an increase in temperature of 150 °C to 950 °C increased the decarburization depth drastically by 150% to 500 μm. This study serves well to demonstrate the need for further study to control or minimize decarburization for the purpose of ensuring the quality and reliability of additively manufactured engineering components.

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Mechanism of Carbon Diffusion in the Iron Sheet During Gas–Solid Decarburization

Cited by 10 publications

References 12 publications

Mitigation of Chromium Poisoning of Ferritic Interconnect from Annealed Spinel of CuFe2O4

Mitigation of Chromium Poisoning of Ferritic Interconnect from Annealed Spinel of CuFe2O4

Analysis of decarburisation mechanism of Fe-C alloy strip

Decarburization of Wire-Arc Additively Manufactured ER70S-6 Steel

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