Corrosion Behavior of Fe-Ni-Al Alloy Inert Anode in Cryolite Melts

Fe-Ni-based alloys are promising materials of inert anodes for use in aluminum electrolysis and adding Al can further improve the corrosion resistance. Fe-Ni-Al alloys with 1.4–8.6 wt.% Al were prepared by vacuum melting, and their corrosion as anodes during the production of pure Al (98.14–99.68%) by electrolysis was studied in a melt of NaF-AlF3-NaCl-CaF2-Al2O3 at 850 °C. The corrosion layer on the anode contains fluorine salt that corrodes the oxide film, and the inner layer is Ni-enriched while the outer layer is enriched with Fe and O due to the preferential oxidation of Fe. The electrolytically deposited oxide films on Fe-Ni-Al alloys with different compositions contains Fe2O3, Fe3O4, NiO, Al2O3, FeAl2O4, NiFe2O4, and other protective oxides, making the alloys very corrosion-resistant. The linear voltammetric curves can be divided into three parts: active dissolution, passivation transition, and over-passivation zones. The alloy with 3.9 wt.% Al (57.9Fe-38.2Ni-3.9Al) has a relatively negative passivation potential, and therefore, is easier to become passivated. According to the Tafel curve, this alloy shows a relatively positive corrosion potential as anode (1.20 V vs. Al/AlF3), and thus can form a protective film.

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Effects of the Duration of Potentiostatic Anodizing on the Corrosion Resistance and Surface Morphology of Films Formed on Mg-Al Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.486-487.125 ◽

2005 ◽

Vol 486-487 ◽

pp. 125-128 ◽

Cited By ~ 1

Author(s):

Seong Jong Kim ◽

Seok Ki Jang ◽

Jeong Il Kim

Keyword(s):

Corrosion Resistance ◽

Surface Morphology ◽

Anodic Oxide ◽

Al Alloys ◽

Anodic Film ◽

Al Alloy ◽

Active Dissolution ◽

Dissolution Reaction ◽

Alloy Az91 ◽

Morphology Of Films

The effects of the duration of potentiostatic anodizing on the corrosion resistance and surface morphology of anodic oxide films formed on Mg-Al alloy (AZ91) in 1 M NaOH were investigated. With the formation of an anodic film, the current density decreased gradually, started to stabilize at 300 s, and was relatively constant at 600 s. These results may be related to the increased time for catalysis of the active dissolution reaction, which not only enlarges the area covered by the anodic film, but also produces a more coherent, thicker film. The reference corrosion potentials of the anodic oxide film for AZ91 shifted in the noble direction with time. In general, the corrosion resistance characteristics were improved with anodizing time.

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Influence of ageing treatment on microstructure, mechanical properties and adhesive wear behaviour of 6063 aluminium alloy

Industrial Lubrication and Tribology ◽

10.1108/ilt-01-2012-0007 ◽

2014 ◽

Vol 66 (4) ◽

pp. 520-524 ◽

Cited By ~ 1

Author(s):

Serkan Büyükdoğan ◽

Süleyman Gündüz ◽

Mustafa Türkmen

Keyword(s):

Mechanical Properties ◽

Wear Resistance ◽

High Speed ◽

Al Alloys ◽

Wear Behaviour ◽

Al Alloy ◽

Strain Ageing ◽

Content Type ◽

Static Strain ◽

Structural Applications

Purpose – The paper aims to provide new observations about static strain ageing in aluminium (Al) alloys which are widely used in structural applications. Design/methodology/approach – The present work aims to provide theoretical and practical information to industries or researchers who may be interested in the effect of static strain ageing on mechanical properties of Al alloys. The data are sorted into the following sections: introduction, materials and experimental procedure, results and discussion and conclusions. Findings – Tensile strength, proof strength (0.2 per cent) and percentage elongation measurement were used to investigate the effect of strain ageing on the mechanical properties. Wear tests were performed by sliding the pin specimens, which were prepared from as-received, solution heat-treated, deformed and undeformed specimens after ageing, on high-speed tool steel (64 HRC). It is concluded that the variations in ageing time improved the strength and wear resistance of the 6063 Al alloy; however, a plastically deformed solution-treated alloy has higher strength and wear resistance than undeformed specimens for different ageing times at 180°C. Practical implications – A very useful source of information for industries using or planning to produce Al alloys. Originality/value – This paper fulfils an identified resource need and offers practical help to the industries.

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Effect of TiN content on properties of NiFe 2 O 4 based ceramic inert anode for aluminum electrolysis

International Journal of Applied Ceramic Technology ◽

10.1111/ijac.13752 ◽

2021 ◽

Author(s):

Zhigang Zhang ◽

Yukun Wang ◽

Guoyin Zu ◽

Zhuokun Cao ◽

Jinli Liu ◽

...

Keyword(s):

Inert Anode ◽

Aluminum Electrolysis ◽

Tin Content

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Direct Cladding from Molten Metals of Aluminum and Magnesium Alloys Using a Tandem Horizontal Twin Roll Caster

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.772.250 ◽

2015 ◽

Vol 772 ◽

pp. 250-256 ◽

Cited By ~ 5

Author(s):

Hideto Harada ◽

Shin Ichi Nishida ◽

Mayumi Suzuki ◽

Hisaki Watari ◽

T. Haga

Keyword(s):

Surface Condition ◽

Hardness Test ◽

Al Alloys ◽

Mg Alloy ◽

Al Alloy ◽

Molten Metals ◽

Electron Probe Micro Analyzer ◽

Twin Roll Caster ◽

Aluminum And Magnesium Alloys ◽

Twin Roll

This paper describes direct cladding of magnesium (Mg) and aluminum (Al) alloys using a tandem horizontal twin roll caster that has three pairs of upper and lower rolls. Manufacturing conditions that are appropriate for fabricating Al/Mg and Al/Mg/Al cladded material were investigated. The surface condition of the cladded cast strip was examined. An electron probe micro analyzer was used to observe the interface between Al alloy and Mg alloy. The thickness of the mixed layer of Al and Mg alloy was 15μm, and how the materials were connected was clarified. Microscopic observation and backscattered electron analysis were used to investigate the cladding mechanisms of the Al and Mg alloy layers. Average hardness was determined using the Vickers hardness test at the Al layer and at the diffused layer between Mg and Al alloys. Cladding of Al/Mg alloy and A/Mg/Al alloy was possible using a tandem twin-roll caster. In addition, Al3Mg2 and Al12Mg17 phase precipitation at the interface of the Al and Mg alloys was confirmed during direct cladding from molten metals.

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Effect of double-sided friction stir welding on the mechanical and microstructural characteristics of AA5754 aluminium alloy

Materials Testing ◽

10.1515/mt-2021-0009 ◽

2021 ◽

Vol 63 (9) ◽

pp. 829-835

Author(s):

Sare Çelik ◽

Fatmagül Tolun

Keyword(s):

Friction Stir Welding ◽

Al Alloys ◽

Fusion Welding ◽

Welding Parameters ◽

Al Alloy ◽

Test Results ◽

Feeding Rates ◽

Microstructural Characteristics ◽

Friction Stir ◽

Tool Tilt Angle

Abstract AA5754Al alloy is widely used in industry. However, as in the case of all Al alloys, the 5xxx series Al alloys cannot be easily joined through fusion welding techniques. To address this problem, in this study, the effect of double-sided friction stir welding at various tool rotational speeds (450, 710, and 900 rpm), feeding rates (40, 50, and 80 mm × min-1), and tool tilt angles (0°, 1°, 2°) on the welding parameters and mechanical and microstructural characteristics of AA5754 Al alloy was determined. Tensile strength tests and microhardness tests were performed to examine the mechanical properties of the welded specimens. The microstructures of the welded zone were examined by obtaining optical microscopy and scanning electron microscopy images. The tensile test results indicated that the specimens exhibited the highest welding performance of 95.17 % at a tool rotational speed, feed rate, and tool tilt angle of 450 rpm, 50 mm × min-1 and 1°, respectively.

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Effect of Nanopowder Content on Properties of NiFe2O4 Matrix Inert Anode for Aluminum Electrolysis

Light Metals 2012 ◽

10.1002/9781118359259.ch239 ◽

2012 ◽

pp. 1381-1384 ◽

Cited By ~ 3

Author(s):

Zhigang Zhang ◽

Yihan Liu ◽

Guangchun Yao ◽

Di Wu ◽

Junfei Ma

Keyword(s):

Inert Anode ◽

Aluminum Electrolysis

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Effect of Voltage on Mg-Li-Al Alloy Anodic Oxide Film

Materials Science Forum ◽

10.4028/www.scientific.net/msf.941.1194 ◽

2018 ◽

Vol 941 ◽

pp. 1194-1197 ◽

Cited By ~ 1

Author(s):

Naoya Miyakita ◽

Natsuki Tanigaki ◽

Taiki Morishige ◽

Toshihide Takenaka

Keyword(s):

Oxide Film ◽

Phosphoric Acid ◽

Anodic Oxidation ◽

Surface Coating ◽

Low Voltage ◽

Active Surface ◽

Anodic Oxide ◽

Al Alloys ◽

Anodic Oxide Film ◽

Al Alloy

Anodic oxidation of Mg-Li-Al alloys using phosphoric acid-based bath were processed to obtain the corrosion-proof surface coating. The specimen oxidized at low voltage anodically dissolved without the formation of oxidized film. Anodic oxidation film could be formed at higher voltage due to thin layer preferentially formed on tthe active surface, this layer develops to stable thick film. There were no significant differences in film thickness between LA141 and LA143 alloys.

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