Internal displacement reactions in multicomponent oxides: Part II. Oxide solid solutions of wide composition range

Reddy, S. N. S.; Wiggins, L. B.; Leonard, D. N.; Jacob, Κ. T.

doi:10.1007/s11661-005-0266-1

Cited by 6 publications

(12 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As part of a study of internal displacement reactions between a metal and a multicomponent oxide, previous articles [1,2] (Parts I and II) considered the reactions involving two types of ternary oxides: (1) line compound of narrow homogeneity range and (2) solid solution of wide composition range. The cation concentration profiles in the reaction zone are qualitatively different for the two types of oxides.…”

Section: Introductionmentioning

confidence: 99%

“…As such, in (A,B) CO mϩn, concentration gradients exist only for A and B and not for C. As a model of Reaction [1], the results for the reaction couple Fe/NiTiO 3 were reported. [1] (2) The displacement reaction inside an oxide of wide composition range is represented as [2] For the sake of simplicity, only the monoxides are considered in Reaction [2]. The oxides AO, BO, and CO have the same crystal structure and form complete solid solutions.…”

Section: Introductionmentioning

confidence: 99%

“…The product oxide, " in which all the cations occupy a single sublattice and their diffusion is strongly correlated. During Reaction [2], at a given location in product oxide, J A ϭ ϪJ B and J C 0. The direction of J C is determined by the thermodynamics of (A,B,C)O solid solution; for most reactions, J C is in the same direction as J A .…”

Section: Introductionmentioning

confidence: 99%

“…As models of Reaction [2], the results for the reaction couples Fe/(Ni x Mg 1-x )O and Fe/(Co 0.5 Mg 0.5 )O were reported. [2] This article considers an internal displacement reaction between a metal and a quaternary solid solution of ternary line compounds, which can be generally represented as [3] where ⌬G 3 is the Gibbs energy change for Reaction [3]. The starting oxide, (B x C 1-x )DO mϩn, is a solid solution of the ternary compounds BDO mϩn and CDO mϩn .…”

Section: Introductionmentioning

confidence: 99%

“…The diffusion of "inert" cations and the concentration profile in the product oxide are dependent on the nature of the oxide: (1) "line" compound of narrow homogeneity range or (2) solid solution of wide composition range. These reactions were discussed in previous articles [1,2] (Parts I and II) along with specific examples. This article is a continuation of studies in Parts I and II and involves the internal displacement reaction between a metal and a quaternary oxide, which is a solid solution of two ternary line compounds.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Internal displacement reactions in multicomponent oxides: Part III. Solid solutions of ternary oxide compounds

Reddy

2005

Metall Mater Trans A

Self Cite

View full text Add to dashboard Cite

In an internal displacement reaction between a reactive metal A and multicomponent oxide (B,C,D,...)O, the noble cation B in the oxide is selectively displaced by reactive metal A, without changing the crystal structure of the oxide. Concurrently, B is precipitated as an internal metal phase in the oxide matrix. The cations (C,D,...) are inert in terms of exchange reaction. The solid-state displacement reaction occurs by the counterdiffusion of A and B inside the reaction zone. The diffusion of "inert" cations and the concentration profile in the product oxide are dependent on the nature of the oxide: (1) "line" compound of narrow homogeneity range or (2) solid solution of wide composition range. These reactions were discussed in previous articles [1,2] (Parts I and II) along with specific examples. This article is a continuation of studies in Parts I and II and involves the internal displacement reaction between a metal and a quaternary oxide, which is a solid solution of two ternary line compounds. As a model, the reaction between Fe and an ilmenite solid solution of NiTiO 3 -MgTiO 3 was studied at 1273 K as a function of time:In ilmenite solid solution (Ni, Fe, Mg) occupy the same cation sublattice, which is different from the Ti sublattice. During the reaction, only Ni cation in the oxide is displaced by Fe; Mg and Ti are "inert" in terms of cation exchange. The reaction products consist of internal "Ni" precipitates (Ni-Fe alloy) in a matrix of (Fe, Mg, Ni)TiO 3 solid solution. In particular, the study focuses on cation flux during the reaction and evolution of product oxide composition profile after time t. The three cations in the product oxide that occupy the same sublattice, (Ni, Fe, Mg), show concentration gradients across the reaction zone, even though Mg is inert for cation displacement. The counterdiffusion of Fe and Ni is consistent with their chemical potential gradients. The diffusion of Mg is in the same direction as that of Fe, indicating that, at constant N MgTiO3 , the chemical potential for MgTiO 3 is higher in (Mg, Fe)TiO 3 solid solution than in (Mg, Ni)TiO 3 solid solution. The concentration of Ti, which occupies a different sublattice, remains constant across the reaction zone (i.e., zero diffusional flux for Ti). The ratio, (Fe ϩ Mg ϩ Ni):Ti ϭ 1:1, is consistent with the ilmenite structure of the product oxide. The shape of the cation concentration profiles indicates that terms containing cross-coefficients in the general flux equations contribute significantly to cation diffusion during the reaction.Fe ϩ (Ni 0.5 Mg 0.5 )TiO 3 ϭ "Ni" ϩ "(Fe 0.5 Mg 0.5 )TiO 3 "

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Internal displacement reactions in multicomponent oxides: Part III. Solid solutions of ternary oxide compounds

Reddy

2005

Metall Mater Trans A

Self Cite

View full text Add to dashboard Cite

show abstract

Internal displacement reactions in multicomponent oxides. Part I. Line compounds with narrow homogeneity range

Reddy¹,

Leonard²,

Wiggins

et al. 2005

Metall Mater Trans A

Self Cite

View full text Add to dashboard Cite

As a model of an internal displacement reaction involving a ternary oxide "line" compound, the following reaction was studied at 1273 K as a function of time, t:Both polycrystalline and single-crystal materials were used as the starting NiTiO 3 oxide. During the reaction, the Ni in the oxide compound is displaced by Fe and it precipitates as a ␥-(Ni-Fe) alloy. The reaction preserves the starting ilmenite structure. The product oxide has a constant Ti concentration across the reaction zone, with variation in the concentration of Fe and Ni, consistent with ilmenite composition. In the case of single-crystal NiTiO 3 as the starting oxide, the ␥ alloy has a "layered" structure and the layer separation is suggestive of Liesegang-type precipitation. In the case of polycrystalline NiTiO 3 as the starting oxide, the alloy precipitates mainly along grain boundaries, with some particles inside the grains. A concentration gradient exists in the alloy across the reaction zone and the composition is Ͼ95 at. pct Ni at the reaction front. The parabolic rate constant for the reaction is k p ϭ 1.3 ϫ 10 Ϫ12 m 2 s Ϫ1 and is nearly the same for both single-crystal and polycrystalline oxides. Fe ϩ NiTiO 3 ϭ "Ni" ϩ "FeTiO 3 "

show abstract

Where did the largest diamonds grow? The experiments on percolation of Fe-Ni melt through olivine matrix in the presence of hydrocarbons

Жимулев

Чепуров

Сонин

2021

Lithos

View full text Add to dashboard Cite

Internal displacement reactions in multicomponent oxides: Part II. Oxide solid solutions of wide composition range

Cited by 6 publications

References 18 publications

Internal displacement reactions in multicomponent oxides: Part III. Solid solutions of ternary oxide compounds

Internal displacement reactions in multicomponent oxides: Part III. Solid solutions of ternary oxide compounds

Internal displacement reactions in multicomponent oxides. Part I. Line compounds with narrow homogeneity range

Where did the largest diamonds grow? The experiments on percolation of Fe-Ni melt through olivine matrix in the presence of hydrocarbons

Contact Info

Product

Resources

About