The wustite-spinel interface

1987 ◽  
Vol 45 ◽  
pp. 268-269
Author(s):  
S.R. Summerfelt ◽  
C.B. Carter
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Strain Energy ◽  
Matrix Material ◽  
Lattice Misfit ◽  
Solid State Reactions ◽  
Oxygen Sublattice ◽  
Large Particles ◽  
Small Lattice ◽  
Coherent Interfaces

The wustite-spinel interface can be viewed as a model interface because the wustite and spinel can share a common f.c.c. oxygen sublattice such that only the cations distribution changes on crossing the interface. In this study, the interface has been formed by a solid state reaction involving either external or internal oxidation. In systems with very small lattice misfit, very large particles (>lμm) with coherent interfaces have been observed. Previously, the wustite-spinel interface had been observed to facet on {111} planes for MgFe2C4 and along {100} planes for MgAl2C4 and MgCr2O4, the spinel then grows preferentially in the <001> direction. Reasons for these experimental observations have been discussed by Henriksen and Kingery by considering the strain energy. The point-defect chemistry of such solid state reactions has been examined by Schmalzried. Although MgO has been the principal matrix material examined, others such as NiO have also been studied.

The Structure of Spinel/Oxide Reaction Fronts During Spinel-Forming Solid State Reactions

1994 ◽  
Vol 357 ◽  
Author(s):  
D. Hesse ◽  
R. Scholz ◽  
S. Senz ◽  
H. Sieber ◽  
P. Werner ◽  
...  
Keyword(s):  
Solid State ◽  
Reaction Front ◽  
Lattice Misfit ◽  
Solid State Reactions ◽  
Interface Plane ◽  
Misfit Dislocations ◽  
Spinel Oxide ◽  
Oxygen Sublattice ◽  
Cross Sectional ◽  
Reaction Fronts

AbstractA series of spinels were grown by topotaxial solid state reaction on MgO(001) and sapphire(11.2) substrates. The structure of the various spinel/oxide reaction fronts was investigated by cross-sectional high resolution electron microscopy and other methods. While for extremely low misfit the reaction front is completely coherent, different interfacial defects form in other cases, depending on sign and amount of the spinel/oxide lattice misfit. For a large positive misfit, a network of misfit dislocations occured all running along <100<, with Burgers vectors of types a/2[101] and a/2[011] pointing out of the interface. The perpendicular Burgers vector component along [001] permits these dislocations to glide in order to cope with the advancing reaction front, avoiding kinetically unfavourable climb processes. The latter have, however, been observed in negative misfit, where the interfacial dislocations run along <110>, with their Burgers vectors lying in the interface plane. At the sapphire/MgAl2O4 front the structure is completely different. Here the h.c.p.-type oxygen sublattice of sapphire is reconstructed into the f.c.c-type oxygen sublattice of the spinel, which requires a tilt of the MgAl2O4 lattice and the formation of interfacial ledges.

Paradigm Change for Solid State Reactions: Synthesis of Lithium Orthophosphate Li3PO4 Nanoparticles by a Water Assisted Solid State Reaction (WASSR) Method

2017 ◽  
Vol 10 (4) ◽  
pp. 592-596 ◽  
Author(s):  
Sun Woog Kim ◽  
Kenji Toda ◽  
Takuya Hasegawa ◽  
Mizuki Watanabe ◽  
Tatsuro Kaneko ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Solid State Reactions ◽  
Paradigm Change

Enhanced production of magnesium silicates from strained magnesia

1965 ◽  
Vol 35 (269) ◽  
pp. 177-188 ◽  
Author(s):  
W. F. Bush ◽  
W. O. Williamson
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Strain Energy ◽  
Free Energies ◽  
Hydrated Silica ◽  
Enhanced Production ◽  
Before And After ◽  
Magnesium Silicates ◽  
The Difference

SummaryMechanically strained, in contrast to annealed, MgO produced greater yields of forsterite and protoenstatite by solid-state reaction with a quartz–cristobalite mixture at 1200–1400° C. The specific surfaces of the strained and of the annealed MgO were similar. The strained MgO was more hygroscopic and similarity of the surface free energies was thus unlikely. The difference in the amounts of silicates produced from the two types of MgO decreased as the temperatures of synthesis increased. This was ascribed to loss of strain energy by unavoidable annealing before and after these temperatures had been reached.Similar results were obtained when hydrated silica was substituted for the quartz-eristobalite mixture, but more forsterite was produced.

Solid-State Reactions in Fe/Si Multilayer Nanofilms

2014 ◽  
Vol 215 ◽  
pp. 144-149 ◽  
Author(s):  
Sergey M. Zharkov ◽  
Roman R. Altunin ◽  
Evgeny T. Moiseenko ◽  
Galina M. Zeer ◽  
Sergey N. Varnakov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Solid State ◽  
Electron Diffraction ◽  
Solid State Reaction ◽  
Room Temperature ◽  
Solid State Reactions ◽  
Transmission Electron ◽  
Reaction Processes

Solid-state reaction processes in Fe/Si multilayer nanofilms have been studied in situ by the methods of transmission electron microscopy and electron diffraction in the process of heating from room temperature up to 900ºС at a heating rate of 8-10ºС/min. The solid-state reaction between the nanolayers of iron and silicon has been established to begin at 350-450ºС increasing with the thickness of the iron layer.

Spinel/oxide interfaces formed by internal solid-state reactions

1983 ◽  
Vol 41 ◽  
pp. 54-55
Author(s):  
K. M. Ostyn ◽  
H. Schmalzried ◽  
C. B. Carter
Keyword(s):  
Solid Solution ◽  
Solid State ◽  
Solid State Reaction ◽  
Elevated Temperatures ◽  
Solid State Reactions ◽  
Second Phase ◽  
Oxide Interfaces ◽  
Valence States ◽  
Internal Reaction ◽  
Kinetics Of

The usual method of forming the spinel AB2O4 by a solid-state reaction is to bring two oxides, AO and B2O3, into contact with one another at elevated temperatures, where diffusion is fast. The spinel then grows into both parent oxides; the kinetics of this solid-state reaction are well understood. Spinel can also be formed by exsoluting it as a second-phase in an oxide matrix. The two distinct internal reaction systems which have been used in this study are internal reduction and internal oxidation. Starting with an (Al-xBx)2O3 (x<1) solid solution, where one of the cations (B) can exist in at least two different valence states, it is possible to form spinel particles in an almost pure A2O3 matrix by internal reduction. Similarly, an (Al-xBX)O solid solution can be internally oxidized to form spinel in an almost pure AO matrix.

The Spinel/Alumina Phase Boundary

1985 ◽  
Vol 43 ◽  
pp. 216-217 ◽  
Author(s):  
Y.M. Kouh ◽  
C.B. Carter ◽  
H. Schmalzried
Keyword(s):  
Solid State ◽  
Phase Boundary ◽  
Solid State Reactions ◽  
Oxygen Sublattice ◽  
Oxygen Ions ◽  
Shockley Partial ◽  
Alumina Phase ◽  
Small Rotation ◽  
Structural Aspects

The formation of spinel during solid-state reactions between two oxides of the type A0 (e.g. Mg0) and B203 (e.g. A1203), has been extensively studied both from a theoretical viewpoint and an experimental one. The present paper will illustrate the structural aspects of the study of the spinel/sesquioxide interface. It has recently been shown by Carter and Schmalzried, that, when Co0 and A1203 react to form Co-Al spinel, the {111} oxygen planes in the spinel do not lie parallel to the (0001) oxygen planes in the parent alumina even though the oxygen ions are almost close-packed in both planes. The small rotation which is present implies that the mechanism whereby the alumina is transformed to spinel is not simply the glide of either isolated, or bundles of, Shockley partial-like transformation dislocations as had previously been assumed, but rather involves a new defect which causes a rotation of the oxygen sublattice.

Artificially Synthesized Non-Coherent Interfaces in Fe-Ti Multilayers and their Influence on Solid State Reactions

1994 ◽  
Vol 343 ◽  
Author(s):  
Z.H. Yan ◽  
M.L. Trudeau ◽  
A. Van Neste ◽  
R. Schulz ◽  
D.H. Ryan ◽  
...  
Keyword(s):  
Solid State ◽  
Amorphous Phase ◽  
Interfacial Structure ◽  
Solid State Reactions ◽  
Interfacial Region ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
Preparation Conditions ◽  
Mössbauer Measurements ◽  
Coherent Interfaces

ABSTRACTThe influence of the interfacial structure on the solid state reaction products in Fe-Ti multilayers has been studied using various preparation conditions and characterization techniques. Sharp and diffused interfaces were produced by using either sequential or co-evaporation in the interfacial region. The reaction product, in the case of the sharp interface, is the bcc supersaturated solid solution of Ti(Fe) while, in the case of the diffused interface, an amorphous phase is formed. Therefore, nucleating the amorphous phase at the interface by local co-evaporation alters the reaction path observed in Fe-Ti multilayers. The solid state reactions were studied using low and high angle X-ray diffraction and Mossbauer measurements. The results are discussed in light of recent thermodynamic calculations on the Fe-Ti system.

Time-Dependent Interfacial Reaction Mechanism in a Spinel-Forming Solid State Reaction Studied by TEM

1996 ◽  
Vol 466 ◽  
Author(s):  
P. Werner ◽  
H. Sieber ◽  
R. Huxebrand ◽  
D. Hesse
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Interfacial Reaction ◽  
Lattice Misfit ◽  
High Resolution Electron Microscopy ◽  
Atomic Scale ◽  
Time Dependent ◽  
Solid State Reactions ◽  
Misfit Dislocations ◽  
Resolution Electron

ABSTRACTInterfacial reaction mechanisms were investigated in case of topotaxial formation of MgIn2O4 spinel on MgO crystals, which is an appropriate model system for thin film solid state reactions in ceramics. The reaction interface MgO/MgIn2O4(001), which is characterized by a large lattice misfit (+4.2%) between these cubic crystals, was investigated by transmission electron microscopy (TEM). Thin spinel films (thickness t< 0.5μm) consist of domains tilted off (≈3.5°) the exact cube-to-cube orientation into four directions, while thicker films (t> 1μm) show an accurate (001) orientation. High-resolution electron microscopy (HREM) showed that this time-dependent orientation behavior correlates with the atomic scale structure of the interface, especially with the different types of misfit dislocations. Based on these results, the misfit accommodation mechanism at the propagating reaction front in this spinel system is discussed including transitions between glide and climb processes.

Movement of the spinel-wustite interface in thin films

1988 ◽  
Vol 46 ◽  
pp. 766-767
Author(s):  
Scott R. Summerfelt ◽  
C.B. Carter
Keyword(s):  
Thin Films ◽  
Interfacial Energy ◽  
Strain Energy ◽  
Lattice Misfit ◽  
Particle Morphology ◽  
Interface Boundary ◽  
Flat Plates ◽  
Oxygen Sublattice

The wustite-spinel interface boundary can be thought of as a model interface since wustite and spinel share a common f.c.c. oxygen sublattice with only the cations changing across the interface. However, a wide variety of spinel precipitate morphologies has been experimentally observed and ranges from flat plates parallel to {001} planes in the MgAl2O4-MgO system, to coherent ellipsoids parallel to the {001} planes in the NiCr2O4-NiO system, to large coherent particles having “arms” in the <001> direction bounded by {111~ and {110~ planes in the NiFe2O4-NiO system. The particle morphology is determined by a combination of the interfacial energy and the strain energy which results from the lattice misfit between the wustite matrix and the spinel precipitate. In this study, a TEM sample was made containing spinel particles precipitated in the bulk. Individual precipitates were then characterized between a series of anneals.

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