scholarly journals In situ TEM Observation of MultiLayer Graphene Formation from CO on Cobalt Nanoparticles at Atmospheric Pressure

2017 ◽  
Vol 23 (S1) ◽  
pp. 896-897 ◽  
Author(s):  
G. Marien Bremmer ◽  
Eirini Zacharaki ◽  
Anja O. Sjastad ◽  
Violeta Navarro ◽  
Joost W. M. Frenken ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Cobalt Nanoparticles ◽  
In Situ Tem ◽  
Multilayer Graphene

In situ TEM studies of the shape evolution of Pd nanocrystals under oxygen and hydrogen environments at atmospheric pressure

2017 ◽  
Vol 53 (99) ◽  
pp. 13213-13216 ◽  
Author(s):  
Xun Zhang ◽  
Jun Meng ◽  
Beien Zhu ◽  
Jian Yu ◽  
Shihui Zou ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
In Situ Tem ◽  
Shape Evolution

The shape evolutions of Pd nanocrystals under oxygen and hydrogen environments at atmospheric pressure were studied using in situ TEM.

scholarly journals Thermal behavior of Pd@SiO2 nanostructures in various gas environments: a combined 3D and in situ TEM approach

Nanoscale ◽  
2018 ◽  
Vol 10 (43) ◽  
pp. 20178-20188 ◽  
Author(s):  
Walid Baaziz ◽  
Mounib Bahri ◽  
Anne Sophie Gay ◽  
Alexandra Chaumonnot ◽  
Denis Uzio ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Behavior ◽  
Atmospheric Pressure ◽  
Electron Tomography ◽  
Core Shell ◽  
In Situ Tem ◽  
Environmental Tem ◽  
First Time ◽  
Thermal Stability Of

The thermal stability of core–shell Pd@SiO2 was for the first time monitored by using in situ Environmental TEM at atmospheric pressure coupled with Electron Tomography on the same particles.

In situ TEM study of the Ru-RuOx/TiO2 catalyst for low temperature methanation of carbondioxide

1990 ◽  
Vol 48 (4) ◽  
pp. 288-289
Author(s):  
P. Ruterana ◽  
P-A. Buffat (I2M) ◽  
K.R Thampi ◽  
M. Graetzel (ICP)
Keyword(s):  
Carbon Dioxide ◽  
Low Temperature ◽  
Surface Area ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Metal Particles ◽  
In Situ Tem ◽  
Tio2 Catalyst ◽  
Optimal Loading

The Ru-RuOx/TiO2 catalyst has been shown to be able to produce methane from hydrogen and carbon dioxide at room temperature and atmospheric pressure at reasonably high rates (TOF: 10-6 at 25C and 10-4 at 90C). The best results were obtained using the P25 support (Degussa 80% anatase and 20% rutile) in the 55-60 m2/g surface area range. The optimal loading for the metal is 3.8% Ru metal.We found that in the most active catalysts, the metal (>90%) is selectively loaded on the rutile crystallites. This distribution shows up clearly in a 500C reduced sample (fig.l) in which the size of the metal particles has increased.

Microstructure and Property Change of Ti-49Al Induced by Hydrogen Charging

2000 ◽  
Vol 646 ◽  
Author(s):  
E. Abe ◽  
K.W. Gao ◽  
M. Nakamura
Keyword(s):  
Atmospheric Pressure ◽  
Single Phase ◽  
Amorphous Region ◽  
Hydrogen Gas ◽  
In Situ Tem ◽  
Al Alloy ◽  
Two Phase ◽  
Hydrogen Charging ◽  
Nano Crystalline

ABSTRACTWe have investigated an effect of hydrogen gas-charging on the microstructure and the mechanical property of a Ti-49at.%Al alloy. After hydrogen-charging performed under an atmospheric pressure of hydrogen gas at 1023K for 3 hours, the alloy with γ-single phase has become completely brittle, while this hydrogen-induced embrittlement is suppressed for that with (γ+α2) two-phase microstructure composed of lath-precipitates in the γ matrix. A significant microstructural change was found to occur for the two-phase alloy (approximately 340ppm hydrogen in the alloy); a thin amorphous layers with a few nm thickness appear at the preexisting γ/α2 interfaces in the lath-precipitates after hydrogen-charging. In-situ TEM observation confirmed that the amorphous region transforms to a nano-crystalline state after heating to 1000K at which the hydrogen could be removed (degassed), indicating that the amorphous phase is not a binary Ti-Al phase but a ternary Ti-Al-H one. This, in turn, suggests that the γ/α2 interface in the lath packets act as the most preferential sites for hydrogen storage. Therefore, the scavenging is expected to occur effectively for the microstructure composed of γ-α2 fine lamellae in which a large number of γ/α2 interfaces exist. It is worthwhile mentioning that the fine-scale of the lamellae makes it possible to have a large number of interfaces for a given volume of the α2 phase.

In situ TEM studies of irradiation effects for materials improvement

1991 ◽  
Vol 49 ◽  
pp. 452-453
Author(s):  
Charles W. Allen
Keyword(s):  
Nuclear Reactor ◽  
Austenitic Stainless Steels ◽  
High Energy ◽  
Point Of View ◽  
In Situ Tem ◽  
Irradiation Effects ◽  
Tem Analysis ◽  
Radiation Induced ◽  
Analytical Tools

Irradiation effects studies employing TEMs as analytical tools have been conducted for almost as many years as materials people have done TEM, motivated largely by materials needs for nuclear reactor development. Such studies have focussed on the behavior both of nuclear fuels and of materials for other reactor components which are subjected to radiation-induced degradation. Especially in the 1950s and 60s, post-irradiation TEM analysis may have been coupled to in situ (in reactor or in pile) experiments (e.g., irradiation-induced creep experiments of austenitic stainless steels). Although necessary from a technological point of view, such experiments are difficult to instrument (measure strain dynamically, e.g.) and control (temperature, e.g.) and require months or even years to perform in a nuclear reactor or in a spallation neutron source. Consequently, methods were sought for simulation of neutroninduced radiation damage of materials, the simulations employing other forms of radiation; in the case of metals and alloys, high energy electrons and high energy ions.

In situ TEM measurements of the electrical properties of interface dislocations

1992 ◽  
Vol 50 (2) ◽  
pp. 1338-1339
Author(s):  
F. M. Ross ◽  
R. Hull ◽  
D. Bahnck ◽  
J. C. Bean ◽  
L. J. Peticolas ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Electronic Device ◽  
In Situ Tem ◽  
Device Performance ◽  
Misfit Dislocations ◽  
Electrical Characteristics ◽  
Strained Layer ◽  
Transmission Electron ◽  
Interfacial Dislocations

We describe an investigation of the electrical properties of interfacial dislocations in strained layer heterostructures. We have been measuring both the structural and electrical characteristics of strained layer p-n junction diodes simultaneously in a transmission electron microscope, enabling us to correlate changes in the electrical characteristics of a device with the formation of dislocations.The presence of dislocations within an electronic device is known to degrade the device performance. This degradation is of increasing significance in the design and processing of novel strained layer devices which may require layer thicknesses above the critical thickness (hc), where it is energetically favourable for the layers to relax by the formation of misfit dislocations at the strained interfaces. In order to quantify how device performance is affected when relaxation occurs we have therefore been investigating the electrical properties of dislocations at the p-n junction in Si/GeSi diodes.

In situ TEM Studies of agglomeration of sub-nanometer Ru layers in Ru/C multilayers

1992 ◽  
Vol 50 (1) ◽  
pp. 256-257
Author(s):  
Tai D. Nguyen ◽  
Ronald Gronsky ◽  
Jeffrey B. Kortright
Keyword(s):  
Layered Structure ◽  
Driving Force ◽  
High Energy ◽  
Superior Performance ◽  
In Situ Tem ◽  
Rayleigh Instability ◽  
Practical Applications ◽  
Transmission Electron ◽  
Diffraction Patterns

Nanometer period Ru/C multilayers are one of the prime candidates for normal incident reflecting mirrors at wavelengths < 10 nm. Superior performance, which requires uniform layers and smooth interfaces, and high stability of the layered structure under thermal loadings are some of the demands in practical applications. Previous studies however show that the Ru layers in the 2 nm period Ru/C multilayer agglomerate upon moderate annealing, and the layered structure is no longer retained. This agglomeration and crystallization of the Ru layers upon annealing to form almost spherical crystallites is a result of the reduction of surface or interfacial energy from die amorphous high energy non-equilibrium state of the as-prepared sample dirough diffusive arrangements of the atoms. Proposed models for mechanism of thin film agglomeration include one analogous to Rayleigh instability, and grain boundary grooving in polycrystalline films. These models however are not necessarily appropriate to explain for the agglomeration in the sub-nanometer amorphous Ru layers in Ru/C multilayers. The Ru-C phase diagram shows a wide miscible gap, which indicates the preference of phase separation between these two materials and provides an additional driving force for agglomeration. In this paper, we study the evolution of the microstructures and layered structure via in-situ Transmission Electron Microscopy (TEM), and attempt to determine the order of occurence of agglomeration and crystallization in the Ru layers by observing the diffraction patterns.

In situ TEM observations of melting in nanosized eutectic Pb-Cd inclusions embedded in Al

1996 ◽  
Vol 54 ◽  
pp. 986-987
Author(s):  
S. Hagège ◽  
U. Dahmen ◽  
E. Johnson ◽  
A. Johansen ◽  
V.S. Tuboltsev
Keyword(s):  
Electron Microscope ◽  
Melt Spinning ◽  
Ternary Alloys ◽  
Solid Matrix ◽  
Eutectic System ◽  
In Situ Tem ◽  
In Situ Observation ◽  
Orientation Relationships ◽  
Transmission Electron

Small particles of a low-melting phase embedded in a solid matrix with a higher melting point offer the possibility of studying the mechanisms of melting and solidification directly by in-situ observation in a transmission electron microscope. Previous studies of Pb, Cd and other low-melting inclusions embedded in an Al matrix have shown well-defined orientation relationships, strongly faceted shapes, and an unusual size-dependent superheating before melting.[e.g. 1,2].In the present study we have examined the shapes and thermal behavior of eutectic Pb-Cd inclusions in Al. Pb and Cd form a simple eutectic system with each other, but both elements are insoluble in solid Al. Ternary alloys of Al (Pb,Cd) were prepared from high purity elements by melt spinning or by sequential ion implantation of the two alloying additions to achieve a total alloying addition of up to lat%. TEM observations were made using a heating stage in a 200kV electron microscope equipped with a video system for recording dynamic behavior.

Postmortem and in situ TEM methods to study the mechanism of failure in controlled-morphology high-impact polystrene resin

1996 ◽  
Vol 54 ◽  
pp. 178-179
Author(s):  
R. C. Cieslinski ◽  
M. T. Dineen ◽  
J. L. Hahnfeld
Keyword(s):  
Poisson Ratio ◽  
Acrylonitrile Butadiene Styrene ◽  
High Impact ◽  
In Situ Tem ◽  
Styrene Copolymers ◽  
Controlled Morphology ◽  
Point Bend ◽  
Mechanism Of Failure ◽  
Impact Energies

Advanced Styrenic resins are being developed throughout the industry to bridge the properties gap between traditional HIPS (High Impact Polystyrene) and ABS (Acrylonitrile-Butadiene-Styrene copolymers) resins. These new resins have an unprecedented balance of high gloss and high impact energies. Dow Chemical's contribution to this area is based on a unique combination of rubber morphologies including labyrinth, onion skin, and core-shell rubber particles. This new resin, referred as a controlled morphology resin (CMR), was investigated to determine the toughening mechanism of this unique rubber morphology. This poster will summarize the initial studies of these resins using the double-notch four-point bend test of Su and Yee, tensile stage electron microscopy, and Poisson Ratio analysis of the fracture mechanism.

Growth kinetics of Al2Cu in an Al-1.5Cu thin film by in Situ TEM

1993 ◽  
Vol 51 ◽  
pp. 1172-1173
Author(s):  
M. Park ◽  
S.J. Krause ◽  
S.R. Wilson
Keyword(s):  
Thin Film ◽  
In Situ Tem ◽  
Collector Plate ◽  
Transmission Electron ◽  
Device Processing ◽  
Corrosion Susceptibility ◽  
Precipitation Phenomena ◽  
Semiconductor Chips ◽  
Kinetics Of

Cu alloying in Al interconnection lines on semiconductor chips improves their resistance to electromigration and hillock growth. Excess Cu in Al can result in the formation of Cu-rich Al2Cu (θ) precipitates. These precipitates can significantly increase corrosion susceptibility due to the galvanic action between the θ-phase and the adjacent Cu-depleted matrix. The size and distribution of the θ-phase are also closely related to the film susceptibility to electromigration voiding. Thus, an important issue is the precipitation phenomena which occur during thermal device processing steps. In bulk alloys, it was found that the θ precipitates can grow via the grain boundary “collector plate mechanism” at rates far greater than allowed by volume diffusion. In a thin film, however, one might expect that the growth rate of a θ precipitate might be altered by interfacial diffusion. In this work, we report on the growth (lengthening) kinetics of the θ-phase in Al-Cu thin films as examined by in-situ isothermal aging in transmission electron microscopy (TEM).

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