Fabrication and Characterization of Functionally Gradient Diamondlike Carbon Coatings

1999 ◽  
Vol 594 ◽  
Author(s):  
Q. Wei ◽  
A.K. Sharma ◽  
S. Yamolenko ◽  
J. Sankar ◽  
J. Narayan
Keyword(s):  
Substrate Surface ◽  
High Vacuum ◽  
Functionally Graded ◽  
Carbon Coatings ◽  
Bonding Structure ◽  
Functionally Gradient ◽  
Transmission Electron ◽  
Alternative Approach ◽  
Diamondlike Carbon

AbstractPure diamondlike carbon thin films largely bonded by four-fold coordination suffer from a large internal compressive stress that gives rise to a serious adhesion problem. In this work, functionally gradient (FG) diamondlike carbon thin coatings were prepared by pulsed laser deposition in a high vacuum chamber as an alternative approach to address the adhesion problem of diamondlike films. Copper, silver and titanium were incorporated into the growing films with their concentration as a function of the distance from the substrate surface. The top of the thin coating is pure DLC of about 400 nm in thickness. The total thickness of the functionally graded superhard DLC coatings can exceed 1.0 μm without buckling. Visible micro-Raman spectroscopy was used to characterize the bonding structure of the layers which contain alloy atoms. High resolution transmission electron microscopy was employed to study the microstructure of the coatings. Nanoscale mechanical characterizations using Nanoindenter XP™ were carried out to study the mechanical behavior of the functionally gradient DLC films.

Fabrication and Characterization of Functionally Gradient Diamond-Like Carbon Coatings

1999 ◽  
Vol 593 ◽  
Author(s):  
Q. Wei ◽  
A. K. Sharma ◽  
S. Yamolenko ◽  
J. Sankar ◽  
J. Narayan
Keyword(s):  
Substrate Surface ◽  
High Vacuum ◽  
Functionally Graded ◽  
Carbon Coatings ◽  
Bonding Structure ◽  
Functionally Gradient ◽  
Transmission Electron ◽  
Alternative Approach ◽  
Diamondlike Carbon

ABSTRACTPure diamondlike carbon thin films largely bonded by four-fold coordination suffer from a large internal compressive stress that gives rise to a serious adhesion problem. In this work, functionally gradient (FG) diamondlike carbon thin coatings were prepared by pulsed laser deposition in a high vacuum chamber as an alternative approach to address the adhesion problem of diamondlike films. Copper, silver and titanium were incorporated into the growing films with their concentration as a function of the distance from the substrate surface. The top of the thin coating is pure DLC of about 400 nm in thickness. The total thickness of the functionally graded superhard DLC coatings can exceed 1.0 μm without buckling. Visible micro-Raman spectroscopy was used to characterize the bonding structure of the layers which contain alloy atoms. High resolution transmission electron microscopy was employed to study the microstructure of the coatings. Nanoscale mechanical characterizations using Nanoindenter XPTM were carried out to study the mechanical behavior of the functionally gradient DLC films.

A Reactor for “Ex-Situ” TEM Catalyst Characterization

1999 ◽  
Vol 5 (S2) ◽  
pp. 926-927 ◽  
Author(s):  
C.E. Kliewer ◽  
M.M. Disko ◽  
S.L Soled ◽  
G.J. DeMartin
Keyword(s):  
Catalytic Properties ◽  
Structural Information ◽  
High Vacuum ◽  
Chemical Characterization ◽  
Ex Situ ◽  
Catalyst Characterization ◽  
Initial Development ◽  
Transmission Electron ◽  
Pressure Variable

The microstructural and chemical characterization of catalysts is not only integral to their initial development but also to understanding and controlling their behavior over time. To better elucidate the morphology of these materials and relate physical properties to catalytic properties (e.g., activity, selectivity, etc.), “ex-situ” methods for studying catalysts under reactive conditions have been developed.Because conventional transmission electron microscopy (CTEM) is conducted under high vacuum conditions, it is difficult to replicate the exact chemical environment of a catalyst (e.g., high pressure, variable gas mixtures, etc) within the TEM. Consequently, most analyses focus on comparing “fresh” and “spent” materials. In general, this methodology provides useful structural information albeit with limitations associated with the comparison of dissimilar regions and the effects of sampling inhomogenieties.

Plasma-assisted deposition and characterization of Ti-containing diamondlike carbon coatings

1998 ◽  
Vol 83 (11) ◽  
pp. 6076-6081 ◽  
Author(s):  
W. J. Meng ◽  
T. J. Curtis ◽  
L. E. Rehn ◽  
P. M. Baldo
Keyword(s):  
Carbon Coatings ◽  
Diamondlike Carbon

scholarly journals Correlation of nanoindentation-induced deformation microstructures in diamondlike carbon coatings on silicon substrates with simulation studies

2010 ◽  
Vol 25 (5) ◽  
pp. 910-920 ◽  
Author(s):  
Ayesha J. Haq ◽  
Paul R. Munroe ◽  
Mark Hoffman ◽  
Phil J. Martin ◽  
Avi Bendavid
Keyword(s):  
Shear Stress ◽  
Silicon Substrate ◽  
Hydrostatic Stress ◽  
Dislocation Motion ◽  
Indentation Load ◽  
Cross Sectional ◽  
Carbon Coatings ◽  
Si Substrates ◽  
Transmission Electron ◽  
Diamondlike Carbon

The effect of the presence of diamondlike carbon coatings deposited on (100) Si substrates on the deformation mechanisms operating in the silicon substrate during contact loading have been investigated by both cross-sectional transmission electron microscopy and modeling of the stresses generated beneath the indenter tip. The observed subsurface microstructures were correlated to the Tresca shear stress and the hydrostatic stress generated in the silicon substrate beneath the indenter tip. The presence of the coating altered the stresses generated in the substrate, and changed the deformation mechanism from one of principally phase transformation in uncoated Si to predominantly dislocation motion in the silicon substrate for the diamondlike C–Si system. The magnitude and distribution of the shear and hydrostatic stresses in the substrate were found to depend on both the indentation load and the thickness of the coating. Furthermore, the observed width of deformation, parallel to the interface, which was found to increase with coating thickness, was correlated to the wider distribution of the Tresca shear stress in the substrate brought about by the presence of the coating.

Structural Characterization of Reaction Product Region in Al/MgO and Al/MgAl2O4 Systems

2011 ◽  
Vol 172-174 ◽  
pp. 1273-1278 ◽  
Author(s):  
Rafal Nowak ◽  
Natalia Sobczak ◽  
Edmund Sienicki ◽  
Jerzy Morgiel
Keyword(s):  
Electron Microscopy ◽  
Single Crystals ◽  
High Vacuum ◽  
Single Layer ◽  
Oxide Phase ◽  
Metallic Phase ◽  
Ultra High Vacuum ◽  
Transmission Electron ◽  
Oxide Particles

The reaction product region, formed between molten aluminium and MgO and MgAl2O4 single crystals of three different crystallographic orientations, was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) coupled with X-ray energy dispersive spectrometry (EDS). The Al/MgO and Al/MgAl2O4 couples were produced under ultra high vacuum at 800, 900 and 1000°C. The observations proved the redox reactions of Al with both MgO and MgAl2O4. Independently of crystallographic orientation of initial oxide single crystals, the reaction product region (RPR) was formed and it was built of oxide particles surrounded by continuous metallic phase. For Al/MgO couples, the RPR was composed of two layers, where in the first layer, the oxide phase was Al2O3 while in the second layer, the MgAl2O4 was identified. In the case of Al/MgAl2O4 couples, a single layer was distinguished and only the Al2O3 phase was recognized.

scholarly journals Electrochemistry at single bimetallic nanoparticles – using nano impacts for sizing and compositional analysis of individual AgAu alloy nanoparticles

2016 ◽  
Vol 193 ◽  
pp. 327-338 ◽  
Author(s):  
En Ning Saw ◽  
Viktoria Grasmik ◽  
Christian Rurainsky ◽  
Matthias Epple ◽  
Kristina Tschulik
Keyword(s):  
Bimetallic Nanoparticles ◽  
Compositional Analysis ◽  
Alloy Nanoparticles ◽  
Bimetallic Alloy ◽  
Single Nanoparticle ◽  
Transmission Electron ◽  
Alternative Approach ◽  
Scanning Transmission ◽  
Modern Technologies

The increasing interest in producing bimetallic nanoparticles and utilizing them in modern technologies sets the demand for fast and affordable characterization of these materials. To date Scanning Transmission Electron Microscopy (STEM) coupled to energy dispersive X-ray spectroscopy is usually used to determine the size and composition of alloy nanoparticles, which is time-consuming and expensive. Here electrochemical single nanoparticle analysis is presented as an alternative approach to infer the particle size and composition of alloy nanoparticles, directly in a dispersion of these particles. As a proof of concept, 14 nm sized Ag0.73Au0.27 alloy nanoparticles are analyzed using a combination of chronoamperometric single nanoparticle analysis and cyclic voltammetry ensemble studies. It is demonstrated that the size, the alloying and the composition can all be inferred using this approach. Thus, the electrochemical characterization of single bimetallic alloy nanoparticles is suggested here as a powerful and convenient complement or alternative to TEM characterization of alloy nanoparticles.

Three Dimensional Characterization of Interfaces in Semiconductors by Scanning Electron Microscopy

1986 ◽  
Vol 69 ◽  
Author(s):  
David C. Joy ◽  
D. M. Maher ◽  
R C Farrow
Keyword(s):  
Electron Microscopy ◽  
Three Dimensional ◽  
Preparation Time ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Alternative Approach ◽  
Imaging Mode ◽  
Structural Characterizations ◽  
Scanning Electron

AbstractIn many semiconductor materials problems, structural characterizations must be achieved in both the lateral and vertical dimensions. Although a combination of cross-sectional and planar transmission electron microscopy can provide this information, the sample preparation time is demanding and only relatively small volumes of material are examined. We describe here an alternative approach in which the charge collection (‘CCM’) imaging mode of the scanning electron microscope (SEM) is used. It is shown that, by varying the incident electron beam energy, electricallly active defects at different positions beneath the entrance surface of the material can be imaged and their depth estimated.

FABRICATION AND CHARACTERIZATION OF FUNCTIONALLY GRADED Ni–Ti MULTILAYER THIN FILMS

2009 ◽  
Vol 02 (02) ◽  
pp. 61-66 ◽  
Author(s):  
H. TIAN ◽  
D. SCHRYVERS ◽  
K. P. MOHANCHANDRA ◽  
G. P. CARMAN ◽  
J. VAN HUMBEECK
Keyword(s):  
Cross Section ◽  
Functionally Graded ◽  
Multilayer Thin Films ◽  
Si Substrate ◽  
Transmission Electron Microscopy Micrographs ◽  
Transmission Electron ◽  
Alloy Target ◽  
Fabrication And Characterization ◽  
Better Than

A functionally graded multilayer Ni – Ti thin film was deposited on a SiO 2/ Si substrate by d.c. sputtering using a ramped heated Ni – Ti alloy target. The stand-alone films were crystallized at 500°C in vacuum better than 10-7 Torr. Transmission electron microscopy micrographs taken along the film cross section show two distinct regions, thin and thick, with weak R and B2 phases, respectively. The film compositions along the thickness were measured and quantified using the standard-less EELSMODEL method. The film deposited during the initial thermal ramp (thin regions) displays an average of 54 at.% Ni while the film deposited at a more elevated target temperature (thick regions) shows about 51 at.% Ni .

scholarly journals Characterization of Sulfur and Nanostructured Sulfur Battery Cathodes in Electron Microscopy Without Sublimation Artifacts

2017 ◽  
Vol 23 (1) ◽  
pp. 155-162 ◽  
Author(s):  
Barnaby D.A. Levin ◽  
Michael J. Zachman ◽  
Jörg G. Werner ◽  
Ritu Sahore ◽  
Kayla X. Nguyen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Vacuum ◽  
Lithium Ion ◽  
Multiple Length Scales ◽  
Transmission Electron ◽  
Nanoscale Characterization ◽  
Infusion Method ◽  
Electron Microscopes ◽  
Sulfur Battery

AbstractLithium sulfur (Li–S) batteries have the potential to provide higher energy storage density at lower cost than conventional lithium ion batteries. A key challenge for Li–S batteries is the loss of sulfur to the electrolyte during cycling. This loss can be mitigated by sequestering the sulfur in nanostructured carbon–sulfur composites. The nanoscale characterization of the sulfur distribution within these complex nanostructured electrodes is normally performed by electron microscopy, but sulfur sublimates and redistributes in the high-vacuum conditions of conventional electron microscopes. The resulting sublimation artifacts render characterization of sulfur in conventional electron microscopes problematic and unreliable. Here, we demonstrate two techniques, cryogenic transmission electron microscopy (cryo-TEM) and scanning electron microscopy in air (airSEM), that enable the reliable characterization of sulfur across multiple length scales by suppressing sulfur sublimation. We use cryo-TEM and airSEM to examine carbon–sulfur composites synthesized for use as Li–S battery cathodes, noting several cases where the commonly employed sulfur melt infusion method is highly inefficient at infiltrating sulfur into porous carbon hosts.

Transmission Electron Microscope Characterization of Siz Selective Deposition of Si-Nanoparticles

1999 ◽  
Vol 5 (S2) ◽  
pp. 752-753
Author(s):  
Hai-Ping Wu ◽  
Kimihiro Nishimura ◽  
Nouari Kebaili ◽  
Haruko Fujinuma ◽  
Kunio Takayanagi
Keyword(s):  
Gas Flow ◽  
Light Emission ◽  
High Vacuum ◽  
Silicon Cluster ◽  
Silicon Clusters ◽  
Size Selection ◽  
Large Size ◽  
Transmission Electron ◽  
Si Nanoparticles

Nanosized semiconductors have been highly desirable as optoelectronic materials since the discovery of photoluminescence from porous nanostructured silicon. There are many investigations about visible light emission from nanostructured semiconductors, and several studies showed the size dependence of the photoluminescent and electronic property [1], [2]. In order to investigate the size effect of those optical properties of nanoparticles, the size-selection technique is important.Size-selection of silicon nanoclusters has been carried out by crossing, an Ar molecular beam perpendicularly to the silicon cluster beam. The laser ablation in inert gas method was used for fabricating nanometer-sized silicon. Large size silicon clusters are produced by Nd:YAG laser irradiation of a silicon wafer which was rotating in ablation chamber under He-gas flow. Produced nanoparticles were extracted through a nozzle ( ϕ = 0.6 mm) to a differentially pumped chamber and then skimmed into a high vacuum chamber for size selection and deposition.

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