Growth stage kinetics in the synthesis of Al2O3/Al composites by directed oxidation of Al-Mg and Al-Mg-Si alloys

Venugopalan, H. S.; DebRoy, T.

doi:10.1016/0955-2219(96)00068-4

Cited by 13 publications

(11 citation statements)

References 21 publications

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“…Although formation of Al 2 O 3 should be a predominant reaction as per Ellingham Diagram, 12 no Al 2 0 3 was detected. This can be attributed to the instantaneous formation of Al 2 O 3 on the surface when the temperature is less than 5,384 K. Because the diffusivity of aluminum through this layer is very low (diffusion coefficient = 10 -11 cm/s 2 and activation energy = 170 kCal/mol), 13,14 and the rate of cooling is very high in LSE, growth of Al 2 O 3 will not proceed to any detectable level. On the contrary, formation of Fe 3 O 4 , possibly because of dissociation of FeO, was detected, indicating an oxygen partial pressure greater than 10 -34 Pa present in the melt pool.…”

Section: Resultsmentioning

confidence: 99%

The laser-assisted iron oxide coating of cast Al auto engines

Dahotre

Nayak

Popoola

2001

JOM

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Narendra B. Dahotre and S. Nayak are with the Department of Materials Science and Engineering Center for Laser Applications at University of Tennessee. Oludele O. Popoola is with the Manufacturing Systems Department at Ford Motor Company. For more information, contact N.B. Dahotre, University of Tennessee, Department of Materials Science and Engineering Center for Laser Applications, Knoxville, TN 37932; (865) 974-0523; fax (865) 974-0530; e-mail ndahotre@ utsi.edu. online at www.tms.org/pubs/ journals/JOM/jom.html JO Visit

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Section: Resultsmentioning

confidence: 99%

The laser-assisted iron oxide coating of cast Al auto engines

Dahotre

Nayak

Popoola

2001

JOM

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“…In the cup test, the sequence of surface reactions of Al alloy (containing Mg and Zn) with air in the gap, as shown in Fig. (a), is believed to occur through the following steps: Al oxidizes to form an alumina layer on the surface of the alloy. This layer grows in thickness with increasing heating temperature to 850°C. Mg present in the alloy reduces alumina to form magnesia.…”

Section: Discussionmentioning

confidence: 99%

Interfacial Reactions Between BaAl₂Si₂O₈ and Molten Al Alloy at 850°C

et al. 2015

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A corrosion cup test was undertaken using BaAl 2 Si 2 O 8 and Al4.1Zn3.2Mg alloy, heated in air for 150 h at 850°C. Electron probe microanalysis, X-ray diffraction, and scanning electron microscopy coupled with energy dispersive spectroscopy were used to identify the mineralogical and microstructural changes at the interfaces. The microstructural results revealed three microstructural areas: (1) Spinel layer with large numbers of Al alloy channels; (2) interfacial area with mainly alumina, spinel, and BaAl 2 Si 2 O 8 ; and (3) interdiffusion zone chemically close to barium hexaaluminate. The principal observations are:1. BaAl 2 Si 2 O 8 was highly resistant to molten Al alloy corrosion owing to sluggish kinetics, as evidenced by the observation of unreacted BaAl 2 Si 2 O 8 grains in the interfacial area. 2. The nature of the microstructure, particularly an interdiffusion zone instead of a continuous layer of precipitated alumina at the interface between the Al alloy channels and the unreacted BaAl 2 Si 2 O 8 supports the conclusion that the corrosion mechanism is governed by interdiffusion (Si/Ba and Al/Mg) and substitution. 3. The formation and limited retention of an MgO layer at the metal-ceramic interface played a critical role in alloy oxidation and the consequent interfacial phenomena.

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“…It seems that magnesium hinders formation of the protective alumina film; therefore, melt oxidation proceeds without any barrier. 8,10 In this step, Al-3 wt. % Mg and Al-5 wt.…”

Section: Oxidation Of Liquid Aluminum-magnesium Alloymentioning

confidence: 99%

“…In pure aluminum, the protective film was weakened by changes in alumina structure whereas, in Al-Mg alloys, formation of metal channels in the protective film could be held responsible. 10 Higher oxidation rates of Al-Mg alloys in the second stage indicated that the second mechanism was more effective on destructing the protective film. In Al-Mg alloys, with more magnesium content, oxidation rate had slight increase.…”

Section: Oxidation Of Liquid Aluminum-magnesium Alloymentioning

confidence: 99%

“…TGA is commonly used for investigating oxidation behavior of aluminum and magnesium for different alloy elements and atmospheres. [8][9][10][11][12][13][14][15][16] Bulk viscosity is another physical property which would be affected by oxidation. It is expected that, by meltatmosphere reactions, some oxides are generated and sunk in the underlying melt.…”

Section: Introductionmentioning

confidence: 99%

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A new method for investigating oxidation behavior of liquid metals

Elahi

Abdi

Shahverdi

2014

Review of Scientific Instruments

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A novel method was introduced to investigate oxidation behavior of melts in different conditions such as flux, alloying element, atmosphere, etc. This approach was based on rheology properties of melts, in which by tracing viscosity variations during oxidation, the behavior of melt can be explored. A modified falling ball viscometer was proposed and used for viscometry. Oxidation of aluminum and Al-Mg alloys was studied using this method. According to the results, it was found that this method was not only a proper approach for investigating oxidation behavior but also could be used as a compliment along conventional approaches.

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Growth stage kinetics in the synthesis of Al2O3/Al composites by directed oxidation of Al-Mg and Al-Mg-Si alloys

Cited by 13 publications

References 21 publications

The laser-assisted iron oxide coating of cast Al auto engines

The laser-assisted iron oxide coating of cast Al auto engines

Interfacial Reactions Between BaAl₂Si₂O₈ and Molten Al Alloy at 850°C

A new method for investigating oxidation behavior of liquid metals

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Growth stage kinetics in the synthesis of Al2O3/Al composites by directed oxidation of Al-Mg and Al-Mg-Si alloys

Cited by 13 publications

References 21 publications

The laser-assisted iron oxide coating of cast Al auto engines

The laser-assisted iron oxide coating of cast Al auto engines

Interfacial Reactions Between BaAl2Si2O8 and Molten Al Alloy at 850°C

A new method for investigating oxidation behavior of liquid metals

Contact Info

Product

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About

Interfacial Reactions Between BaAl₂Si₂O₈ and Molten Al Alloy at 850°C