The Diffusion Process of Methane through a Silicalite Single Crystal Membrane

2002 ◽  
Vol 106 (20) ◽  
pp. 5163-5168 ◽  
Author(s):  
M. Goktug Ahunbay ◽  
J. Richard Elliott ◽  
Orhan Talu
Keyword(s):  
Diffusion Process ◽  
Single Crystal

Boron Segregation and Out-diffusion in Single-Crystal Si 1-y C y

2003 ◽  
Vol 765 ◽  
Author(s):  
E. J. Stewart ◽  
J.C. Sturm
Keyword(s):  
Diffusion Process ◽  
Single Crystal ◽  
Carbon Diffusion ◽  
Subsequent Oxidation ◽  
Boron Segregation ◽  
Carbon Precipitation

AbstractBoron segregation and its effect on carbon diffusion is studied in single-crystal Si1-yCy. We find that boron segregates from silicon to Si0.996C0.004 at a level m=[B]SiC/[B]Si = 1.7 during a 2 hour, 850°Cannealin N2. After this anneal, if most of the carbon is then removed from the Si1-yCy layer (via an oxidation-enhanced out-diffusion process), most of the boron segregation is removed as well. This argues against immobile B-C defects as the predominant mechanism driving the segregation. Boron is shown to increase carbon diffusion during the N2 anneal, but also appears to enhance carbon precipitation during a subsequent oxidation.

scholarly journals Effect of Interactions Among Elements on Diffusion Process Associated with γ′ Coarsening in a Ni-Based Single-Crystal Superalloy

2020 ◽  
Vol 33 (7) ◽  
pp. 1013-1020
Author(s):  
Guang-Lei Wang ◽  
Dong-Qing Qi ◽  
Ji-De Liu ◽  
Jin-Lai Liu ◽  
Yi-Zhou Zhou ◽  
...  
Keyword(s):  
Diffusion Process ◽  
Single Crystal ◽  
Single Crystal Superalloy

scholarly journals Unexpected Precipitation of a Re-Rich Phase in Single Crystal Superalloy CMSX-4 during Thermal Exposure

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Kuiyu Cheng ◽  
ChangYong Jo ◽  
DooHyun Kim ◽  
Tao Jin ◽  
Zhuangqi Hu
Keyword(s):  
Diffusion Process ◽  
Single Crystal ◽  
Interdendritic Region ◽  
Thermal Exposure ◽  
Dendrite Core ◽  
Single Crystal Superalloy ◽  
Core Formation ◽  
Rich Phase

A Re-rich phase (up to 85.40% wt.Re) was occasionally found in a single crystal superalloy during thermal exposure. Interestingly, this phase is located in front of the dendrite periphery in the interdendritic region, while the Re is segregated in the dendrite core. Formation of this phase was suggested to relate to the unusual accumulation of the Re resulting from the uneven diffusion process of Re. Appearance of this phase may imply the preference of forming Re-Re atomic bond in the superalloys.

Solvent diffusion through a non-porous crystal ‘caught in the act’ and related single-crystal-to-single-crystal transformations in a cationic dinuclear Ag(i) complex

CrystEngComm ◽  
2015 ◽  
Vol 17 (46) ◽  
pp. 8957-8964 ◽  
Author(s):  
Jo Alen ◽  
Luc Van Meervelt ◽  
Wim Dehaen ◽  
Liliana Dobrzańska
Keyword(s):  
Diffusion Process ◽  
Single Crystal ◽  
Crystal Lattice ◽  
Solvent Diffusion ◽  
Solvent Uptake ◽  
Porous Crystal

A few snapshots of a dynamic solvent diffusion process through a seemingly non-porous crystal of a dinuclear, cyclic Ag(i) complex were revealed. These indicate the complexity of the process, which involves not only relocation of the molecules in the crystal lattice, but also conformational adjustments of the metallocycles in response to solvent uptake/release.

scholarly journals Study on abnormal hot corrosion behavior of nickel-based single-crystal superalloy at 900 °C after drilling

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Zehao Chen ◽  
Mengmeng Wu ◽  
Yanling Pei ◽  
Shusuo Li ◽  
Shengkai Gong
Keyword(s):  
Diffusion Process ◽  
Single Crystal ◽  
Oxide Layer ◽  
Corrosion Behavior ◽  
Surface Stress ◽  
Hot Corrosion ◽  
Single Crystal Superalloy ◽  
Alloying Elements ◽  
Stable Oxide ◽  
Change Of Microstructure

AbstractThe hot corrosion behavior of nickel-based single-crystal superalloy after drilling is investigated at 900 °C. The characteristics of hot corrosion after drilling which are different from normal hot corrosion are reflected in the formation of a more stable oxide layer and less severe spallation. The change of microstructure around the hole is the main reason for the formation of a stable oxide layer during hot corrosion by changing the diffusion process of alloying elements. Subsequently, the formation of a stable oxide layer can reduce the effect of spalling by optimizing surface stress.

A Preparation of High Resolution Standards for Electron Microscopy. Part II

1971 ◽  
Vol 29 ◽  
pp. 160-161
Author(s):  
Akira Tanaka ◽  
David F. Harling
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Carbon Black ◽  
Single Crystal ◽  
Dark Field ◽  
Graphitized Carbon Black ◽  
Graphitized Carbon ◽  
Dark Field Imaging ◽  
Crystal Films ◽  
Micro Holes

In the previous paper, the author reported on a technique for preparing vapor-deposited single crystal films as high resolution standards for electron microscopy. The present paper is intended to describe the preparation of several high resolution standards for dark field microscopy and also to mention some results obtained from these studies. Three preparations were used initially: 1.) Graphitized carbon black, 2.) Epitaxially grown particles of different metals prepared by vapor deposition, and 3.) Particles grown epitaxially on the edge of micro-holes formed in a gold single crystal film.The authors successfully obtained dark field micrographs demonstrating the 3.4Å lattice spacing of graphitized carbon black and the Au single crystal (111) lattice of 2.35Å. The latter spacing is especially suitable for dark field imaging because of its preparation, as in 3.), above. After the deposited film of Au (001) orientation is prepared at 400°C the substrate temperature is raised, resulting in the formation of many square micro-holes caused by partial evaporation of the Au film.

Structure of Palladium Single-Crystal Films Prepared by Flash Evaporation onto (001) NaCl Substrates

1970 ◽  
Vol 28 ◽  
pp. 456-457
Author(s):  
L. E. Murr ◽  
G. Wong
Keyword(s):  
Single Crystal ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
High Rate ◽  
Flash Evaporation ◽  
Optimum Load ◽  
Single Crystal Films ◽  
Crystal Films ◽  
A Current

Palladium single-crystal films have been prepared by Matthews in ultra-high vacuum by evaporation onto (001) NaCl substrates cleaved in-situ, and maintained at ∼ 350° C. Murr has also produced large-grained and single-crystal Pd films by high-rate evaporation onto (001) NaCl air-cleaved substrates at 350°C. In the present work, very large (∼ 3cm2), continuous single-crystal films of Pd have been prepared by flash evaporation onto air-cleaved (001) NaCl substrates at temperatures at or below 250°C. Evaporation rates estimated to be ≧ 2000 Å/sec, were obtained by effectively short-circuiting 1 mil tungsten evaporation boats in a self-regulating system which maintained an optimum load current of approximately 90 amperes; corresponding to a current density through the boat of ∼ 4 × 104 amperes/cm2.

Dislocations, Ordering and Antiferromagnetic Domains in MnO

1970 ◽  
Vol 28 ◽  
pp. 522-523
Author(s):  
D. J. Barber ◽  
R. G. Evans
Keyword(s):  
Electron Diffraction ◽  
Single Crystal ◽  
Optical Microscopy ◽  
Defect Chemistry ◽  
Magnetic Structures ◽  
Optically Transparent ◽  
Magnetic Features ◽  
Antiferromagnetic Domains

Manganese (II) oxide, MnO, in common with CoO, NiO and FeO, possesses the NaCl structure and shows antiferromagnetism below its Neel point, Tn∼ 122 K. However, the defect chemistry of the four oxides is different and the magnetic structures are not identical. The non-stoichiometry in MnO2 small (∼2%) and below the Tn the spins lie in (111) planes. Previous work reported observations of magnetic features in CoO and NiO. The aim of our work was to find explanations for certain resonance results on antiferromagnetic MnO.Foils of single crystal MnO were prepared from shaped discs by dissolution in a mixture of HCl and HNO3. Optical microscopy revealed that the etch-pitted foils contained cruciform-shaped precipitates, often thick and proud of the surface but red-colored when optically transparent (MnO is green). Electron diffraction and probe microanalysis indicated that the precipitates were Mn2O3, in contrast with recent findings of Co3O4 in CoO.

Electron Microscopy of Shock Loaded Polycrystalline Beryllium

1974 ◽  
Vol 32 ◽  
pp. 506-507 ◽  
Author(s):  
J. M. Galbraith ◽  
L. E. Murr ◽  
A. L. Stevens
Keyword(s):  
Electron Microscopy ◽  
Wave Propagation ◽  
Structural Change ◽  
Single Crystal ◽  
Diffraction Pattern ◽  
Shock Loading ◽  
Slip Systems ◽  
Compression Tests ◽  
X Ray Diffraction ◽  
X Ray

Uniaxial compression tests and hydrostatic tests at pressures up to 27 kbars have been performed to determine operating slip systems in single crystal and polycrystal1ine beryllium. A recent study has been made of wave propagation in single crystal beryllium by shock loading to selectively activate various slip systems, and this has been followed by a study of wave propagation and spallation in textured, polycrystal1ine beryllium. An alteration in the X-ray diffraction pattern has been noted after shock loading, but this alteration has not yet been correlated with any structural change occurring during shock loading of polycrystal1ine beryllium.This study is being conducted in an effort to characterize the effects of shock loading on textured, polycrystal1ine beryllium. Samples were fabricated from a billet of Kawecki-Berylco hot pressed HP-10 beryllium.

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