Native Air-Formed Oxide Film and its Effect on Magnesium Alloys Corrosion

In order to develop ignition-proof magnesium alloys, the effect of alloying element Ce on the ignition-proof properties and surface tension of AZ91D-2.5Ca alloy were investigated. The results show that the addition of Ce can significantly raise the ignition temperature and change the structure of surface oxide film as well as the surface tension. When the Ce content increases to 1.2%, the ignition point reaches 1371K. Upon the addition of Ce, the oxide film of AZ91D-2.5Ca melt changes to fine and close structure from the porous structure before the Ce addition. The composite oxide film mainly composed of MgO, Al2O3, CaO and Ce2O3. The surface tension of AZ91D-2.5Ca decrease with the increasing Ce content, as the active-element Ce enriched at the melt surface.

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Environmental Effect on Fatigue Properties of Die-Cast Magnesium Alloys

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.152-154.548 ◽

2012 ◽

Vol 152-154 ◽

pp. 548-553

Author(s):

Ma Bao Liu ◽

Qi Da Liu ◽

Xian Hui Wang ◽

Hong Gao

Keyword(s):

Oxide Film ◽

Magnesium Alloys ◽

Environmental Effect ◽

Ambient Air ◽

Fatigue Properties ◽

Nacl Solution ◽

Die Cast ◽

Endurance Limits ◽

Cast Magnesium Alloys ◽

Cast Magnesium

In order to study the environmental effect on fatigue properties of die-cast magnesium alloys, several fatigue tests were performed for AM50HP and AZ91HP in ambient air, vacuum, engine oil, deionized water and 3.5% NaCl solution. It is found that the S-N curves are steeper in corrosive environment and AM50HP shows a higher sensitivity to the action of 3.5% NaCl solution than AZ91HP. Both alloys do not have endurance limits in 3.5% NaCl solution, whereas endurance limits could be detected in ambient air, which are about 90MPa and 100MPa for AZ91HP and AM50HP respectively. It is also found that FCP rate is substantially increased in corrosion media: the presence of oxygen causes the production of oxide film on the fresh surfaces made during the cyclic loading and the oxide film would restrict the deformation of the matrix beneath the hard film and promote hydrogen embrittlement in the wet condition.

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Optimization of Environmentally Friendly Anodic Oxide Film for Magnesium Alloys

MATERIALS TRANSACTIONS ◽

10.2320/matertrans.47.1013 ◽

2006 ◽

Vol 47 (4) ◽

pp. 1013-1019 ◽

Cited By ~ 10

Author(s):

Masaaki Hara ◽

Kenji Matsuda ◽

Wataru Yamauchi ◽

Masaaki Sakaguchi ◽

Toshiyuki Yoshikata ◽

...

Keyword(s):

Oxide Film ◽

Magnesium Alloys ◽

Environmentally Friendly ◽

Anodic Oxide ◽

Anodic Oxide Film

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Graphene oxide as a corrosion-inhibitive coating on magnesium alloys

RSC Advances ◽

10.1039/c5ra05974g ◽

2015 ◽

Vol 5 (55) ◽

pp. 44149-44159 ◽

Cited By ~ 35

Author(s):

Zhaozhong Qiu ◽

Rui Wang ◽

Jinzhu Wu ◽

Yushen Zhang ◽

Yunfei Qu ◽

...

Keyword(s):

Graphene Oxide ◽

Oxide Film ◽

Magnesium Alloys ◽

Self Assembly ◽

Physical Separation ◽

Assembly Method ◽

Peo Coatings

A graphene oxide film was formed on the PEO coatings of magnesium alloys via an electrostatic self-assembly method, which functioned as a physical separation with inhibiting effects between the protected metal and reactants.

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Deposited emulsion particles in the pores of aluminum oxide film

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109392 ◽

1978 ◽

Vol 36 (1) ◽

pp. 450-451

Author(s):

Michio Ashida ◽

Yasukiyo Ueda

Keyword(s):

Oxide Film ◽

Acid Solution ◽

Barrier Layer ◽

Colloidal Particles ◽

Oxalic Acid Solution ◽

Anodic Oxide ◽

Anodic Oxide Film ◽

Carbon Replica ◽

Sectioning Method ◽

Thin Sectioning

An anodic oxide film is formed on aluminum in an acidic elecrolyte during anodizing. The structure of the oxide film was observed directly by carbon replica method(l) and ultra-thin sectioning method(2). The oxide film consists of barrier layer and porous layer constructed with fine hexagonal cellular structure. The diameter of micro pores and the thickness of barrier layer depend on the applying voltage and electrolyte. Because the dimension of the pore corresponds to that of colloidal particles, many metals deposit in the pores. When the oxide film is treated as anode in emulsion of polyelectrolyte, the emulsion particles migrate onto the film and deposit on it. We investigated the behavior of the emulsion particles during electrodeposition.Aluminum foils (99.3%) were anodized in either 0.25M oxalic acid solution at 30°C or 3M sulfuric acid solution at 20°C. After washing with distilled water, the oxide films used as anode were coated with emulsion particles by applying voltage of 200V and then they were cured at 190°C for 30 minutes.

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The nature of the oxide film formed on stainless steel immersed in concentrated hydrogen peroxide (H.T.P.)

Journal of Biochemical Toxicology ◽

10.1002/jbt.2570101205 ◽

1960 ◽

Vol 10 (12) ◽

pp. 497-505

Author(s):

J. Diederichsen

Keyword(s):

Hydrogen Peroxide ◽

Stainless Steel ◽

Oxide Film

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Determination of rare earth metals in magnesium alloys by atomic emission spectrometry with inductively coupled plasma

Izmeritel`naya Tekhnika ◽

10.32446/0368-1025it.2019-4-62-66 ◽

2019 ◽

pp. 62-66

Author(s):

R. M. Dvoretskov ◽

V. B. Baranovskaya ◽

F. N. Karachevtsev ◽

A. F. Letov

Keyword(s):

Rare Earth ◽

Magnesium Alloys ◽

Inductively Coupled Plasma ◽

Rare Earth Metals ◽

Atomic Emission ◽

Atomic Emission Spectrometry ◽

Emission Spectrometry ◽

Inductively Coupled

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Microstructural and Mechanical Behaviour Evaluation of Mg-Al-Zn Alloy Friction Stir Welded Joint

International Journal of Automotive and Mechanical Engineering ◽

10.15282/ijame.17.3.2020.08.0612 ◽

2020 ◽

Vol 17 (3) ◽

pp. 8150-8159

Author(s):

Kulwant Singh ◽

Gurbhinder Singh ◽

Harmeet Singh

Keyword(s):

Heat Treatment ◽

Friction Stir Welding ◽

Magnesium Alloys ◽

Mechanical Performance ◽

Fuel Efficiency ◽

Research Work ◽

Grain Structure ◽

Tensile Fracture ◽

Friction Stir ◽

The Impact

The weight reduction concept is most effective to reduce the emissions of greenhouse gases from vehicles, which also improves fuel efficiency. Amongst lightweight materials, magnesium alloys are attractive to the automotive sector as a structural material. Welding feasibility of magnesium alloys acts as an influential role in its usage for lightweight prospects. Friction stir welding (FSW) is an appropriate technique as compared to other welding techniques to join magnesium alloys. Field of friction stir welding is emerging in the current scenario. The friction stir welding technique has been selected to weld AZ91 magnesium alloys in the current research work. The microstructure and mechanical characteristics of the produced FSW butt joints have been investigated. Further, the influence of post welding heat treatment (at 260 °C for 1 h) on these properties has also been examined. Post welding heat treatment (PWHT) resulted in the improvement of the grain structure of weld zones which affected the mechanical performance of the joints. After heat treatment, the tensile strength and elongation of the joint increased by 12.6 % and 31.9 % respectively. It is proven that after PWHT, the microhardness of the stir zone reduced and a comparatively smoothened microhardness profile of the FSW joint obtained. No considerable variation in the location of the tensile fracture was witnessed after PWHT. The results show that the impact toughness of the weld joints further decreases after post welding heat treatment.

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