ChemInform Abstract: TEM Investigations of Spinel-Forming Solid State Reactions: Reaction Mechanism, Film Orientation, and Interface Structure During MgAl2O4 Formation on MgO (001) and Al2O3 (11.2) Single Crystal Substrates.

ChemInform ◽  
2010 ◽  
Vol 28 (1) ◽  
pp. no-no
Author(s):  
H. SIEBER ◽  
D. HESSE ◽  
X. PAN ◽  
ST. SENZ ◽  
J. HEYDENREICH
2020 ◽  
Vol 49 (18) ◽  
pp. 5932-5938
Author(s):  
Yunwei Zhao ◽  
Pengfei Jiang ◽  
Wenliang Gao ◽  
Rihong Cong ◽  
Jing Ju ◽  
...  

A high level of Eu3+ (7 atom%) was doped successfully, suggesting the possible single crystal growth of bi-functional RE3+-doped δ-BiB3O6.


1991 ◽  
Vol 6 (9) ◽  
pp. 1958-1963 ◽  
Author(s):  
David W. Susnitzky ◽  
C. Barry Carter

Solid-state reactions between bulk samples of copper oxide and alumina have been studied using scanning electron microscopy and electron microprobe analysis. Both CuAl2O4 and CuAlO2 were found to form during reactions in air at 1100 °C between CuO powder and single-crystal alumina substrates. The relative position of the CuAl2O4 and CuAlO2 layers was observed to depend on the crystallographic orientation of the surface of the alumina substrate: CuAl2O4 formed in contact with (0001) alumina substrates while CuAlO2 formed when the alumina substrate surface was (110). Faceted Cu–aluminate/alumina phase boundaries were observed to develop when single-crystal alumina rods were reacted with CuO, although the interfaces invariably tended to be wavy.


1997 ◽  
Vol 52 (5) ◽  
pp. 643-646 ◽  
Author(s):  
M. Staack ◽  
Hk. Müller-Buschbaum

Abstract The compound Co6O2 [TeO4(CoAsO5)2] has been prepared by solid state reactions. Single crystal X -ray techniques led to orthorhombic symmetry, space group D 182h-Cmca, a = 6.020(1), b = 23.763(5), c = 8.841(2) Å , Z = 4. The new structure type contains the hitherto unknown cobaltoarsenate group CoAsO7, oxidic oxygen connected exclusively to cobalt, and TeO6 octahedra.


1994 ◽  
Vol 9 (3) ◽  
pp. 648-657 ◽  
Author(s):  
J.S. Chen ◽  
E. Kolawa ◽  
M-A. Nicolet ◽  
R.P. Ruiz ◽  
L. Baud ◽  
...  

Thermally induced solid-state reactions between a 70 nm Pt film and a single-crystal (001) β-SiC substrate at temperatures from 300 °C to 1000 °C for various time durations are investigated by 2 MeV He backscattering spectrometry, x-ray diffraction, secondary ion mass spectrometry, scanning electron microscopy, and cross-sectional transmission electron microscopy. Backscattering spectrometry shows that Pt reacts with SiC at 500 °C. The product phase identified by x-ray diffraction is Pt3Si. At 600–900 °C, the main reaction product is Pt2Si, but the depth distribution of the Pt atoms changes with annealing temperature. When the sample is annealed at 1000 °C, the surface morphology deteriorates with the formation of some dendrite-like hillocks; both Pt2Si and PtSi are detected by x-ray diffraction. Samples annealed at 500–900 °C have a double-layer structure with a silicide surface layer and a carbon-silicide mixed layer below in contact with the substrate. The SiC—Pt interaction is resolved at an atomic scale with high-resolution electron microscopy. It is found that the grains of the sputtered Pt film first align themselves preferentially along an orientation of {111}Pt//{001}SiC without reaction between Pt and SiC. A thin amorphous interlayer then forms at 400 °C. At 450 °C, a new crystalline phase nucleates discretely at the Pt-interlayer interface and projects into or across the amorphous interlayer toward the SiC, while the undisturbed amorphous interlayer between the newly formed crystallites maintains its thickness. These nuclei grow extensively down into the substrate region at 500 °C, and the rest of the Pt film is converted to Pt3Si. Comparison between the thermal reaction of SiC-Pt and that of Si–Pt is discussed.


1969 ◽  
Vol 77 (890) ◽  
pp. 341-347 ◽  
Author(s):  
Hideo TAGAI ◽  
Takayoshi ISEKI ◽  
Takeo SAEKI ◽  
Toshiro KOUNOSU

A synchrotron X-ray topographic examination has been made of the structural changes that occur during the polymerization of 2,4-hexadiynediol bis( p -toluene sulphonate) monomer crystals by radiolytic, photolytic and thermal means, in situ in the synchrotron X-ray beam. Exposure of the monomer crystals to the full synchrotron X-ray beam ( λ ≈ 0.01-0.3 nm) yields rapid polymerization which results in the complete transformation of monomer crystal to polymer crystal by a single crystal to single crystal transformation. Filtering the softer components ( λ > 0.1 nm) from the beam allowed the extension of the induction period to polymerization to an extent which enabled the study of structural changes that occurred during preliminary photo and thermal polymerization before the initiation of rapid X-ray polymerization. The results show that radiolytic and photolytic polymerization initiate and progress uniformly in the bulk and surface regions of the crystal respectively. These processes are not apparently influenced by the presence of dislocations or other recognizable structural defects (twins and growth sector boundaries) in the crystal. In contrast, thermal polymerization initiates in the locus of bundles of growth dislocations and inclusions in the crystal. Single dislocations do not appear to act as nuclei. The mechanism by which preferential nucleation can occur at groups of dislocations is discussed.


1997 ◽  
Vol 52 (9) ◽  
pp. 1031-1036 ◽  
Author(s):  
Nicola Zoche ◽  
Martin Jansen

K3BiO3 and Rb3BiO3 have been synthesized for the first time by solid state reactions of the respective binary compounds. K3BiO3 was obtained from Bi2O3 and K2O at 550 °C, Rb3BiO3 from Bi2O3 and Rb2O at 650 °C. The compounds were structurally examined by single-crystal X -ray investigations (K3BiO3: I 4̅ 3 m, a = 1070.15(2) pm, Z = 8; Rb3BiO3: P 21 3, a = 875.48(2) pm, Z = 4). The structures reveal “isolated” BiO33- groups. While K3BiO3 is isostructural to Na3BiO3, Rb3BiO3 has the same crystal structure as Cs3BiO3.


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