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Deevi, S.C.; Sikka, V.K.; Swindeman, C.J.; Seals, Roland D

doi:10.1023/a:1018691826809

Cited by 36 publications

(12 citation statements)

References 7 publications

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“…However, Mössbauer results presented below indicated the presence of the Fe 3 Al phase. Fe-Al intermetallic phases occur when Fe is in contact with melted aluminum [8,10,11], condition met in this thermite process, especially in the case of thermite samples with aluminum in excess. The iron-rich Fe-Al intermetallic phase, Fe 3 Al, is likely to occur in the thermite products since, with the Fe 2 O 3 :Al equivalence ratios used, the iron produced in thermite reaction is in a much higher amount than the exceeding aluminum.…”

Section: Resultsmentioning

confidence: 99%

Fe2O3/aluminum thermite reaction intermediate and final products characterization

Durães

Costa

Santos³

et al. 2007

Materials Science and Engineering: A

124

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Radial combustion experiments on Fe 2 O 3 /aluminum thermite thin circular samples were conducted. A stoichiometric (Fe 2 O 3 + 2Al) and four over aluminized mixtures were tested. The combustion products were characterized by X-ray diffraction and Mössbauer spectroscopy and the influence of Fe 2 O 3 /aluminum ratio on their composition was assessed. The main products were identified as alumina (␣-Al 2 O 3 ) and iron (Fe). A significant amount of hercynite (FeAl 2 O 4 ) was detected, decreasing with the aluminum excess in the reactants. Close to the sample/confinement interface, where reaction quenching occurs, a non-stoichiometric alumina (Al 2.667 O 4 ) was observed, being its XRD intensity correlated to the hercynite amount. Fe 3 Al intermetallic phase was found in the products of over aluminized mixtures. A reaction mechanism was proposed comprising: (i) Fe 2 O 3 reduction to Fe 3 O 4 and FeO; (ii) Al oxidation to Al 2 O 3 ; (iii) interaction of the remaining Al with Fe 3 O 4 and FeO with formation of iron-aluminates (hercynite) and iron; (iv) for the over aluminized mixtures, incorporation of Al into the iron-aluminates takes place with the formation of iron and alumina and, in parallel, Al reacts with iron to produce intermetallics.

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Section: Resultsmentioning

confidence: 99%

Fe2O3/aluminum thermite reaction intermediate and final products characterization

Durães

Costa

Santos³

et al. 2007

Materials Science and Engineering: A

124

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“…A control of the spraying parameters with the objective to obtain coatings with unique exploiting properties like resistance to abrasive wear, erosion, corrosion, high temperature corrosion or thermal shocks, as well as good adhesion and low porosity was the subject of number of works [1][2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Meta-stable Solidification Created by the Detonation Method of Coating Formation

Wołczyński¹,

Garzeł²,

Morgiel³

et al. 2012

Archives of Foundry Engineering

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Particles of the Fe-Al type (less than 50 µm in diameter) were sprayed onto the 045 steel substrate by means of the detonation method. The TEM, SAED and EDX analyses revealed that the Fe-Al particles have been partially melted in the experiment of coating formation. Particle undergone melting even within about 80% of its volume. Therefore, solidification of the melted part of particles was expected. Solidification differed significantly due to a large range of chemical composition of applied particles (from 15 at.% Al up to 63 at.% Al). A single particle containing 63 at.% Al was subjected to the detailed analysis, only. The TEM / SAED techniques revealed in the solidified part of particle three sub-layers: an amorphous phase, A ε , periodically situated FeAl + Fe 2 Al 5 phases, and a non-equilibrium phase, N ε .A hypothesis dealing with the inter-metallic phases formation in such a single particle of the nominal composition 0 0.63 N = is presented. At first, the solid / liquid system is treated as an interconnection: / / substrate liquid nonmelted particle part . Therefore, it is suggested that the solidification occurs simultaneously in two directions: towards a substrate and towards a non-melted part of particle. The solidification mechanism is referred to the Fe-Al meta-stable phase diagram. It is shown that the melted part of particle solidifies rapidly according to the phase diagram of meta-stable equilibrium and at a significant deviation from the thermodynamic equilibrium.

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“…As indicated by Morsi, [1] of the five Al-Ni intermetallic phases in the Al-Ni system, AlNi and AlNi 3 have received the most attention. Because of their high strength-to-weight ratio, good high-temperature stability, and good corrosion resistance, nickel aluminides may be found in a large variety of structural applications such as aircraft or automotive components.…”

Section: Introductionmentioning

confidence: 99%

“…Because of their high strength-to-weight ratio, good high-temperature stability, and good corrosion resistance, nickel aluminides may be found in a large variety of structural applications such as aircraft or automotive components. Of the many methods attempted to process nickel aluminides, [2][3][4][5][6] combustion synthesis (CS), wherein the products are directly synthesized from their precursors, offers a latitude in process conditions that is unmatched by other, more conventional techniques. The CS of metastable Ni ϩ Al mixtures has been studied by several groups.…”

Section: Introductionmentioning

confidence: 99%

Severe plastic deformation of nickel-coated aluminum precursor powders at elevated temperatures

Kecskes

Woodman²,

Barber

et al. 2006

Metall Mater Trans A

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Two nickel (Ni)-coated aluminum (Al) powders were consolidated to full or near-full density by using the equal-channel angular extrusion (ECAE) technique. Mixtures (in at. pct) of 78Al-22Ni (63Al-37Ni in wt pct), hereafter termed Al-22Ni, and of 39Al-61Ni (23Al-77Ni in wt pct), hereafter termed Al-61Ni, were placed in square-shaped copper (Cu) or Ni casings, sealed, and heated to a uniform temperature. Subsequently, the billets were dropped into the ECAE die and were single-pass extruded. Preheating temperatures ranged from ambient temperature to 700 °C. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and microhardness measurements were used to examine the resultant intermetallics. The onset and nature of the transformation from the precursors into the products were further studied by differential thermal analysis. It was found that the preheating temperature affected the transformation of the Ni-coated Al powder into a nickel-aluminide intermetallic. Specifically, samples of Al-22Ni and Al-61Ni, preheated and consolidated below the nominal reaction temperature of Ni and Al, consisted of a cellular Al structure interposed with a Ni boundary layer. The samples preheated and consolidated above this temperature consisted of Al 3 Ni and Al 3 Ni 2 , AlNi, and AlNi 3 , respectively. In this case, ECAE caused the multiphase structure of the intermetallics to homogenize and disperse; this was more so for 78Al-22Ni than for 39Al-61Ni. It was also found that the use of a Ni vs Cu casing material greatly improved the densification of the powders. Unlike that found with the Cu casing, full densification using a Ni casing was achieved in a single pass.

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Untitled

Cited by 36 publications

References 7 publications

Fe2O3/aluminum thermite reaction intermediate and final products characterization

Fe2O3/aluminum thermite reaction intermediate and final products characterization

Meta-stable Solidification Created by the Detonation Method of Coating Formation

Severe plastic deformation of nickel-coated aluminum precursor powders at elevated temperatures

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