Oxidation behaviour of molten magnesium and AZ91D magnesium alloy in 1,1,1,2-tetrafluoroethane/air atmospheres

Liu, Jianrui; Chen, Hukui; Zhao, Lun; Huang, Weidong

doi:10.1016/j.corsci.2008.10.011

Cited by 33 publications

(10 citation statements)

References 5 publications

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“…Liu and co-workers [57] using TGA measurements found that pure Mg and AZ91 exposed at 760 C in air containing 0.001 vol.% HFC-134a exhibited linear oxidation kinetics without an incubation period. This implied that the rapid oxidation occurred directly on the surface of the melt.…”

Section: Molten Alloysmentioning

confidence: 98%

“…This implied that the rapid oxidation occurred directly on the surface of the melt. The oxidation products on the surface of the pure Mg were MgO and Mg3N2, whereas the surface of the AZ91 melt contained MgO with small amounts of Mg3N2, AlN, MgAl2O4 [57]. AlN and Mg3N2 were considered as burning products as a result of the chemical reaction of nitrogen with Al and Mg vapour during burning [56].…”

Section: Molten Alloysmentioning

confidence: 99%

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Oxidation of magnesium alloys at elevated temperatures in air: A review

et al. 2016

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Highlights The oxidation behaviours of Mg alloys from low to high temperatures are reviewed. Characteristics of MgO during oxidation is discussed. Mechanisms of Mg oxidation is presented. Effect of various alloying elements is analysed. AbstractThis paper reviews (i) the oxidation of Mg alloys at elevated temperatures in air; (ii) the influence of alloying elements on the oxidation of Mg alloys; and (iii) the progress in the development of oxidation-resistant Mg alloys. Low oxidation rates have been shown by Mg alloys containing the alloying elements, Ca, Be and rare earth elements. However, these alloying elements may also decrease mechanical properties, such as ductility.

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Section: Molten Alloysmentioning

confidence: 98%

Section: Molten Alloysmentioning

confidence: 99%

Oxidation of magnesium alloys at elevated temperatures in air: A review

et al. 2016

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“…This film does also not protect the magnesium melt and its alloys from oxidation. It even burns at high temperatures of melting and casting processes [2]. So that, it needs to protect the molten magnesium from oxidation.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, researchers mentioned about 18 times lower global warming potential of HFC-134a than SF6. On the contrary, the atmospheric lifetime of HFC-134a is only 0.46% of SF6 [2][3][4][5][6]. In literature, understanding of the mechanism of SF6, a melting technology in a sealed furnace was proposed, and the protection behavior of magnesium alloys in the sealed melting furnace was investigated under the protective atmosphere containing HFC-134a [7].…”

Section: Introductionmentioning

confidence: 99%

Investigation of Protective Surface Film Behavior of Fluorine Containing Cover Gas Parameters on Molten Magnesium Alloy

Vanli¹,

Akdogan²,

Eryıldız³

2020

Pamukkale J Eng Sci

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ÖzProtection of molten magnesium is one of the most important issues for existing and potential magnesium users. An effective melt protection system is necessary for safety reasons as well as minimizing expensive metal losses. Since SF6 has an extremely high global warming potential, HFC-134a is an effective solution in many applications. In this study, surface films formed on molten AZ91A alloy under HFC-134a/N2 atmosphere are examined in various parameters such as molten metal temperatures, exposure times, concentrations and flow rates of the protective gases. The obtained surface films as a result of the experiments were analyzed by optical microscope. The Taguchi experimental design method was used to determine the optimum process parameters. Process parameters provide the best protective layer on the melt; exposure time of 60 min, molten magnesium temperature of 660 °C, concentration of 0.30% vol., and the flow rate of protective gas mixture of 600 l/h. were determined.Ergimiş magnezyumun korunması, mevcut ve potansiyel magnezyum kullanıcıları için en önemli konulardan biridir. Pahalı metal kayıplarının en az seviyeye indirilmesinin yanı sıra güvenlik gibi nedenlerinden de ötürü, etkili bir ergiyik koruma sistemi gereklidir. SF6, son derece yüksek bir küresel ısınma potansiyeline sahip olduğundan, HFC-134a birçok uygulamada etkili bir çözümdür. Bu çalışmada, HFC-134a/N2 atmosferi altında ergimiş AZ91A alaşımında oluşan yüzey filmleri, farklı ergimiş metal sıcaklıkları, temas süreleri, konsantrasyonları ve koruyucu gaz debileri gibi çeşitli parametrelerde incelenmektedir. Optimum işlem parametrelerinin belirlenmesi için Taguchi deneysel tasarım yöntemi kullanılmıştır. Deneyler neticesinde elde edilen yüzey filmleri optik mikroskop ile analiz edilmiştir. Proses parametrelerinin ergiyik üzerinde en iyi koruyucu tabaka sağlayanları; 60 dakikalık temas süresi, 660 °C ergimiş magnezyum sıcaklığı, % 0.30 hacimsel gaz konsantrasyon ve 600 l/h'lik koruyucu gaz karışım debisi olarak belirlenmiştir.

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“…Since SF 6 has been identified as a GHG [5,7,8], the protective films formed on molten magnesium and its alloys under gas protection have been an active subject of research, with the aim of finding suitable industrial alternatives to SF 6 gas for melt protection [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. The use of SF 6 gas will be banned from the European Union from 2018 [22] (as cited in Reference [23]), in which case, replacement of SF 6 as a cover gas in the Mg industry would no longer be eligible as Clean Development Mechanism (CDM) project or Joint Implementation (JI) project, nor sell the reduced emission as 'carbon credits' [24].…”

Section: Introductionmentioning

confidence: 99%

Melt Protection of Mg-Al Based Alloys

Balart

Patel

Fan

2016

Metals

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This paper reports the current status of Mg melt protection in view to identify near-future challenges, but also opportunities, for Mg melt protection of Mg-Al based alloys. The goal is to design and manufacture sustainable Mg alloys for resource efficiency, recycling and minimising waste. Among alternative cover gas technologies for Mg melt protection other than SF 6 : commercially available technologies containing-HFC-134a, fluorinated ketone and dilute SO 2 -and developed technologies containing solid CO 2 , BF 3 and SO 2 F 2 , can potentially produce toxic and/or corrosive by-products. On the other hand, additions of alkaline earth metal oxides to Mg and its alloys have developed a strong comparative advantage in the field of Mg melt protection. The near-future challenges and opportunities for Mg-Al based alloys include optimising and using CO 2 gas as feedstock for both melt protection and grain refinement and TiO 2 additions for melt protection.

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Oxidation behaviour of molten magnesium and AZ91D magnesium alloy in 1,1,1,2-tetrafluoroethane/air atmospheres

Cited by 33 publications

References 5 publications

Oxidation of magnesium alloys at elevated temperatures in air: A review

Oxidation of magnesium alloys at elevated temperatures in air: A review

Investigation of Protective Surface Film Behavior of Fluorine Containing Cover Gas Parameters on Molten Magnesium Alloy

Melt Protection of Mg-Al Based Alloys

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