High Resolution Transmission Electron Microscopy of an automobile catalytic converter

1990 ◽  
Vol 48 (4) ◽  
pp. 242-243
Author(s):  
Jan-Olle Malm ◽  
Jan-Olov Bovin
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Catalytic Converter ◽  
Active Material ◽  
Image Intensifier ◽  
High Resolution Electron Microscopy ◽  
Detailed Knowledge ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Atomic Surface

Understanding of catalytic processes requires detailed knowledge of the catalyst. As heterogeneous catalysis is a surface phenomena the understanding of the atomic surface structure of both the active material and the support material is of utmost importance. This work is a high resolution electron microscopy (HREM) study of different phases found in a used automobile catalytic converter.The high resolution micrographs were obtained with a JEM-4000EX working with a structural resolution better than 0.17 nm and equipped with a Gatan 622 TV-camera with an image intensifier. Some work (e.g. EDS-analysis and diffraction) was done with a JEM-2000FX equipped with a Link AN10000 EDX spectrometer. The catalytic converter in this study has been used under normal driving conditions for several years and has also been poisoned by using leaded fuel. To prepare the sample, parts of the monolith were crushed, dispersed in methanol and a drop of the dispersion was placed on the holey carbon grid.

Structure of InAs Quantum Dots in Si Matrix Investigated by High Resolution Electron Microscopy

1999 ◽  
Vol 571 ◽  
Author(s):  
N. D. Zakharov ◽  
P. Werner ◽  
V. M. Ustinov ◽  
A.R. Kovsh ◽  
G. E. Cirlin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Critical Thickness ◽  
High Resolution Electron Microscopy ◽  
Geometrical Parameters ◽  
Inas Quantum Dots ◽  
Temperature Growth ◽  
Transmission Electron ◽  
Resolution Electron

ABSTRACTQuantum dot structures containing 2 and 7 layers of small coherent InAs clusters embedded into a Si single crystal matrix were grown by MBE. The structure of these clusters was investigated by high resolution transmission electron microscopy. The crystallographic quality of the structure severely depends on the substrate temperature, growth sequence, and the geometrical parameters of the sample. The investigation demonstrates that Si can incorporate a limited volume of InAs in a form of small coherent clusters about 3 nm in diameter. If the deposited InAs layer exceeds a critical thickness, large dislocated InAs precipitates are formed during Si overgrowth accumulating the excess of InAs.

Silicon-Sapphire Interface: A High Resolution Electron Microscopy Study

1980 ◽  
Vol 2 ◽  
Author(s):  
Fernando A. Ponce
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Silicon Layer ◽  
High Resolution Electron Microscopy ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Resolution Limit ◽  
High Concentration ◽  
Transmission Electron ◽  
Resolution Electron

ABSTRACTThe structure of the silicon-sapphire interface of CVD silicon on a (1102) sapphire substrate has been studied in crøss section by high resolution transmission electron microscopy. Multibeam images of the interface region have been obtained where both the silicon and sapphire lattices are directly resolved. The interface is observed to be planar and abrupt to the instrument resolution limit of 3 Å. No interfacial phase is evident. Defects are inhomogeneously distributed at the interface: relatively defect-free regions are observed in the silicon layer in addition to regions with high concentration of defects.

High Resolution Electron Microscopy Observations About The Interface Structure In A Ti/TiN Multilayer Material

1991 ◽  
Vol 238 ◽  
Author(s):  
X. G. Ning ◽  
L. P. Guo ◽  
R. F. Huang ◽  
J. Gong ◽  
B. H. Yu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Orientation Relationship ◽  
High Resolution Electron Microscopy ◽  
Interface Structure ◽  
Multilayer Material ◽  
Transition Layers ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Specific Orientation

ABSTRACTThe interface structure in a Ti/TiN multilayer material has been investigated by high resolution transmission electron microscopy (HRTEM). It was shown that the α-Ti and β-TiN layers consisted of many cylindrical crystals growing along the close packed directions normal to the surface of a stainless steel. There existed specific orientation relationship at the Ti/TiN interfaces without transition layers: (111)TiN ‖ (001)Ti, [110]TiN ‖ [100]Ti. However there was no such orientation relationship at the Ti/TiN interfaces with TixN (x >1) transition layers.

Combined Use of Small Angle Neutron Scattering (Sans) and (Conventional and High Resolution) Electron Microscopy for the Characterization of Early Stages of Ordering and Phase Separation in Ni-Ti

1986 ◽  
Vol 82 ◽  
Author(s):  
A. Cerri ◽  
R. Schmelczer ◽  
P. Schwander ◽  
G. Kostorz ◽  
A.F. Wright
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Tem Analysis ◽  
Zone Formation ◽  
Early Stages ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Combined Use ◽  
Integrated Intensity

ABSTRACTThe decomposition of Ni ∼ 11.5 at.% Ti single crystals was studied for an ageing temperature of 540°C. In this alloy, coherent ordered zones of γ′-Ni3Ti (Cu3Au structure) are formed prior to the stable n precipitates. The early stages of zone formation were investigated by in-beam SANS and transmission electron microscopy (TEM). Electron diffraction, high resolution electron microscopy, TEM analysis of dislocation arrangements in samples deformed after ageing and X-ray measurements of the integrated intensity at L12 superstructure positions show that ordered regions already appear in quenched samples, whereas compositional changes, as determined by SANS measurements, occur only upon ageing.

High Resolution Transmission Electron Microscopy of Partial States of Oxygen Order in YBa2Cu3Oz

1990 ◽  
Vol 183 ◽  
Author(s):  
C. P. Burmester ◽  
S. Quong ◽  
L. T. Wille ◽  
R. Gronsky ◽  
B. T. Ahn ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Contrast Effects ◽  
Oxygen Loss ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Out Of Plane ◽  
Partial States

AbstractHigh resolution electron microscopy is used to investigate the effect of electron irradiation induced oxygen loss on the states of partial order in YBa2Cu3Oz. Contrast effects visible in the [001] zone image as a result of the degree of the out-of-plane correlation of these ordered states are investigated. Using statistical simulations to aid in the analysis of the HREM images, an interpretation based on a kinetically limited evolution of the variation of long range [001] ordering is proposed.

Transmission electron microscopy study of Co/Pd and Co/Au multilayers

1993 ◽  
Vol 8 (5) ◽  
pp. 1019-1027 ◽  
Author(s):  
F. Hakkens ◽  
A. De Veirman ◽  
W. Coene ◽  
Broeder F.J.A. den
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Microscopy Study ◽  
Columnar Structure ◽  
Electron Microscopy Study ◽  
Misfit Dislocations ◽  
Transmission Electron ◽  
Resolution Electron

The structure of Co/Pd and Co/Au (111) multilayers is studied using transmission electron microscopy and high resolution electron microscopy. We focused on microstructure, atomic stacking (especially at the interfaces), and coherency, as these are structural properties that have considerable magnetic effects. A columnar structure with a strong curvature of the multilayer influenced by substrate temperature during growth is observed. High resolution imaging shows numerous steps at the interfaces of the multilayer structure and the presence of misfit dislocations. In bright-field images, periodic contrast fringes are observed at these interfaces as the result of moiré interference. These moiré fringes are used to study the misfit relaxation at the interfaces, whereas electron diffraction gives the average relaxation over the whole layer. Both measurements determined that, for Co/Pd as well as Co/Au multilayers, 80–85% of the misfit is relaxed and 20–15% remains in the form of strain, independent of the Co layer thickness in the regime studied.

scholarly journals Vitrification of Y zeolite and its effects on HREM images

1986 ◽  
Vol 44 ◽  
pp. 774-775
Author(s):  
R. Csencsits
Keyword(s):  
Electron Microscopy ◽  
Computer Simulation ◽  
Electron Microscope ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Systematic Investigation ◽  
Y Zeolite ◽  
Y Zeolites ◽  
Transmission Electron ◽  
Resolution Electron

High resolution electron microscopy (HREM) is a valuable technique for studying catalytic zeolite systems because it gives direct information about the structure and defects present in the structure. The difficulty with doing an HREM study on zeolites is that they become amorphous under electron irradiation. This work is a systematic investigation of the damage of Y zeolites in the transmission electron microscope (TEM); the goals of this study are to determine the mechanism for electron damage and to access the effects of damage in Y zeolites on their HREM images using computer simulation.

Unstained Biological Specimens in High Resolution Electron Microscopy

1974 ◽  
Vol 32 ◽  
pp. 234-235
Author(s):  
M. K. Lamvik ◽  
J. M. Pullman ◽  
A. V. Crewe
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Heavy Atom ◽  
High Resolution Electron Microscopy ◽  
Scanning Transmission Electron Microscope ◽  
Dark Field ◽  
Structural Studies ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Scanning Transmission

Negative staining and high resolution shadowing have been extensively used for structural studies in electron microscopy. However, these techniques cover the specimen with a layer of heavy salt or metal, and hence do not allow determination of true mass distribution or localization of specific sites using heavy atom markers. A prerequisite for such structural studies is an examination of unstained specimens. For thin specimens dark field microscopy must be used to obtain adequate contrast. The scanning transmission electron microscope is preferred for such studies since elastic, energyloss, and unscattered electrons can be recorded and analyzed quantitatively to form images with a minimum of beam-induced damage.

Elucidation of the crystal structure of oxyapatite by high-resolution electron microscopy

1999 ◽  
Vol 55 (2) ◽  
pp. 170-176 ◽  
Author(s):  
Peter Alberius Henning ◽  
Angel R. Landa-Cánovas ◽  
Ann-Kristin Larsson ◽  
Sven Lidin
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Structural Model ◽  
High Resolution Electron Microscopy ◽  
Group Symmetry ◽  
Space Group ◽  
Threefold Symmetry ◽  
Transmission Electron ◽  
Crude Model ◽  
Resolution Electron

High-resolution electron-microscopy (HREM) images from different hydroxyapatite (OHAp) samples showed p3 projection symmetry along [001] instead of the p6 projection symmetry compatible with the space group P6_3/m of OHAp. Image processing was used to establish without ambiguity that threefold symmetry dominates the images along [001]. OHAp crystals decompose in the transmission electron microscope and it is concluded that the threefold symmetry observed corresponds to an early step in the decomposition process, the dehydration of OHAp to oxyapatite (OAp). A structural model for OAp where every second O atom along the 63 axis in OHAp is removed has the maximal space-group symmetry P\bar6. This is compatible with the p3 projection symmetry observed. Atomic shifts in this OAp model compared to the OHAp structure were estimated using the HREM images and geometric optimizations of the atomic structure. No refinements of the atomic coordinates against diffraction data were possible but the simulated HREM images of this crude model fit well with the experimental images.

On the interpretation of electron diffraction patterns from materials containing planar boundaries: the intergrowth tungsten bronzes

1990 ◽  
Vol 429 (1876) ◽  
pp. 91-117 ◽  
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Electron Diffraction ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
General Interest ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Resolution Imaging ◽  
Diffraction Patterns

Materials containing planar boundaries are of general interest and complete understanding of their structures is important. When direct imaging of the boundaries by, for instance, high-resolution electron microscopy, is impracticable, details of their structure and arrangement may be obtained from electron diffraction patterns. Such patterns are discussed in terms of those from intergrowth tungsten bronzes as specific examples. Fourier-transform calculations for proposed structures have been made to establish, in conjunction with optical-diffraction analogues, the features of the far-field diffraction patterns. These results have been compared with diffraction patterns obtained experimentally by transmission electron microscopy. The aim of the study, to show that the arrangement of the boundaries in these complicated phases can be deduced from their diffraction patterns without the need for high-resolution imaging, has been achieved. The steps to be taken to make these deductions are set out.

Sign in / Sign up

Export Citation Format

Share Document