THE EFFECT OF INCIDENT ATOMIC VELOCITY ON THE STRUCTURE OF EVAPORATED SILVER FILMS

1956 ◽  
Vol 34 (8) ◽  
pp. 731-736 ◽  
Author(s):  
R. A. Aziz ◽  
G. D. Scott
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
High Vacuum ◽  
The Other ◽  
Qualitative Explanation ◽  
Nitrogen Gas ◽  
Silver Films ◽  
Resistivity Measurements

The influence of the incident atomic velocity on the structure of evaporated films has been studied for silver films in the thickness range from 50 to 500 Å. The thermal velocities of the evaporated atoms were reduced (i) by "reflection" from a teflon surface at room temperature, and (ii) by "diffusion" through nitrogen gas at 3.0 μ. Films formed by these two methods are compared with "normal" high vacuum films for the same rates of deposition, which were relatively slow (0.4 to 4 Å of thickness per second). The results of both resistivity measurements and electron microscopy show that "diffusion" films are less aggregated, i.e. more continuous, than "normal" high vacuum films. "Reflected" films have a structure intermediate between the other two. A qualitative explanation of the observed effects is given in terms of the formation of nuclei and the growth of aggregates.

Comparison of Hydrogen Sulfide Sensing Properties between Multiple-Walled Carbon Nanotubes (MWNTs) and MWNTs-HAuCl4 Materials

2014 ◽  
Vol 936 ◽  
pp. 310-314
Author(s):  
Si Xuan He ◽  
Guang Zhong Xie ◽  
Ya Dong Jiang ◽  
Guang Di Zhang ◽  
Yong Zhou
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Hydrogen Sulfide ◽  
Response Time ◽  
Room Temperature ◽  
The Other ◽  
High Toxicity ◽  
Walled Carbon Nanotubes ◽  
Scanning Electron

The rapid and precise detection of hydrogen sulfide (H2S) has great significance due to its high toxicity. In this work, the response properties of multiple-walled carbon nanotubes (MWNTs) and MWNTs-HAuCl4 to H2S at room temperature were compared. Scanning electron microscopy (SEM) technique was used to characterize MWNTs and MWNTs-HAuCl4 films. It was found that sensors with MWNTs-HAuCl4 exhibited much higher response value. On the other hand, sensors with MWNTs were observed to have faster response time and better recovery properties.

Investigation of Ti3SiC2 MAX Phase Formation onto N-Type 4H-SiC

2012 ◽  
Vol 717-720 ◽  
pp. 845-848 ◽  
Author(s):  
Alexia Drevin-Bazin ◽  
Jean François Barbot ◽  
Thierry Cabioc’h ◽  
Marie France Beaufort
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
High Vacuum ◽  
Max Phase ◽  
Vacuum System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Annealing Temperatures ◽  
Transmission Electron

In this study, investigations on MAX phase Ti3SiC2 formation to n-type 4H-SiC substrates and its ohmic-behaved are reported. Ti-Al layers were deposited onto SiC substrates at room temperature by magnetron sputtering in high vacuum system. Thermal annealing at 1000°C in Ar atmosphere were performed to allow interdiffusion processes. X-ray diffraction and High Resolution Transmission Electron Microscopy reveal that a Ti3SiC2 contact, in perfect epitaxy with 4H-SiC substrate, is so-obtained. In situ annealing experiment underlines the evolution of Ti-Al contact microstructure versus temperature. The evolution of contact system from Schottky to Ohmic behaved is observed by I-V measurements for annealing temperatures larger than 700°C.

The crystallography and nucleation of pearlite

1973 ◽  
Vol 333 (1595) ◽  
pp. 455-467 ◽  
Keyword(s):  
Electron Microscopy ◽  
Grain Boundaries ◽  
Room Temperature ◽  
Thin Foil ◽  
The Other ◽  
Morphological Aspects ◽  
Austenite Grain ◽  
Orientation Relations ◽  
Iron Manganese ◽  
Thin Foil Electron

By choice of a suitable iron—manganese—carbon alloy it has been possible to study pearlite nodules growing in austenite, without the austenite transforming on cooling to room temperature. Thin foil electron microscopy has been used to examine the orientation relations between cementite, ferrite and austenite as well as morphological aspects of the transformation. It is shown that one of the classical ferrite—cementite orientation relations found in pearlite (Pitsch—Petch) arises when the pearlite colonies nucleate on ‘clean’ austenite grain boundaries. The other familiar relation (Bagaryatski) arises when the colonies nucleate on pre-existing hyper-eutectoid cementite layers at the austenite grain boundaries. Some observations are made on the mode of nucleation of the pearlite nodules.

Reflection Electron Microscopy (REM) of Surface Steps & Dislocations on GaP(110) & GaAs(110)

1982 ◽  
Vol 40 ◽  
pp. 450-451
Author(s):  
Tung Hsu ◽  
Sumio Iijima
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Heating Stage ◽  
Surface Steps ◽  
Reflection Electron Microscopy ◽  
Electron Microscopes ◽  
High Vacuum Environment

Reflection electron microscopy (REM) in ultra high vacuum environment with heating stage has been reported by Osakabe, et al. In this paper, we present our results in REM imaging of single steps and dislocations using commercial electron microscopes (JEM-100B and Philips-400T) under ordinary pressure (10-7 torr) and room temperature.

Development of high-vacuum equipment for EM specimen preparation

1992 ◽  
Vol 50 (2) ◽  
pp. 1082-1083
Author(s):  
Richard A. Denton
Keyword(s):  
Electron Microscopy ◽  
High Vacuum ◽  
The Other ◽  
Specimen Preparation ◽  
Vacuum Equipment ◽  
Optical Film ◽  
Diffusion Pump ◽  
Shadow Casting ◽  
Mechanical Pump ◽  
The U.S

High-vacuum techniques made electron microscopy possible. In the 1930s vacuum evaporators with glass or metal chambers, diffusion pumps and oil sealed mechanical pumps were used in Europe and the U.S. The earliest systems used mercury pumps with liquid air traps. Oil diffusion pumps were manufactured in the U.S. by D.P.I. from glass or metal. In 1940 the first RCA TEM went into production as the EMB. First shadow casting in the U.S. was by Williams and Wycoff in 1944 and in Europe by Műller in 1942. Due to war secrecy, neither knew about the other. In 1944 RCA built the first production evaporator for EM under the direction of Bob Picard. The system had an 18" dia. glass bell jar and a metal baseplate with an oil diffusion pump backed by a Cenco Hypervac 20 mechanical pump. In 1948 Optical Film Engineering designed a 12" dia. bell jar evaporator for EM. This SC-3 employed a Welch 5 cfm mechanical pump and a 3" diffusion pump. Carbon evaporation for substrates or replicas was invented by D.E. Bradley in England and published in 1954.

Electron Microscopy investigations of buried Si3N4 isolation layers

1990 ◽  
Vol 48 (4) ◽  
pp. 642-643
Author(s):  
S.K. Maksimov ◽  
V.N. Kukin
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Cross Section ◽  
Room Temperature ◽  
Ion Beam ◽  
The Other ◽  
Silicon Epitaxial Layer ◽  
P Type ◽  
Structure Investigations ◽  
Plane View

Formation of buried Si3N4 layers obtained by using repeated cycles of implantation and annealing has been investigated. Structure investigations were made with the use of a CM30 Twin electron microscope (whose diaphragm is 0.18 nm-1 ). In HREM studies, axial micrographs in Si reflections of the 000, 111 and 220 types were employed. Two types of samples were used: "plane view" samples and those of a "cross section". Si3N4 precipitates were identified by application of the EELS method on the LN and Lsiedges.N+ - ions were implanted into silicon wafers (of p-type, (001), 10 Ω cm) at a room temperature- The dose pf ions implanted in each cycle was 5.1010 cm-2 . The total dose was 5.1017 cm-2 , The energy of ions - 150 keV, the current density of the ion beam 25 μA/cm-2 . Annealing in the atmosphere of nitrogen was made at 1100° C which lasted 2 hours after the first cycle of implantation; in the other cycles it lasted 0.5 hours at 850° C. After the operation of ion beam synthesis was completed a silicon epitaxial layer 0.8-1 μm thick was grown.

The Influence of B4C on Mechanical Properties of MgO-SiC Based Refractory Castables

2013 ◽  
Vol 634-638 ◽  
pp. 2397-2401 ◽  
Author(s):  
Jun Cong Wei ◽  
Jing Wang ◽  
Jun Bo Tu
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Liquid Phase ◽  
Room Temperature ◽  
The Other ◽  
Cold Strength ◽  
Refractory Castables ◽  
Direct Binding ◽  
Scanning Electron

The effects of B4C addition on the room temperature physical properties and hot mechanical properties of MgO-SiC based refractory castables were investigated using magnesia and SiC fines as starting materials and silica fume as a binder. The microstructure was characterized by scanning electron microscopy (SEM). The results showed that drying strength of MgO-SiC based castables decreased with the increase in B4C addition, the immediate temperature strength and hot temperature strength increased. The HMOR at 1400°C for 0.5h decreased. This is because B4C oxidized and produced a liquid phase during heating, contributing to sintering and making the material denser. So the cold strength increased. On the other hand, due to the formation of liquids, direct binding reduced and the HMOR decreased

Effects of Pulsed Magnetic Treatment on Mechanical Characteristics of Manufactured Parts

2006 ◽  
Author(s):  
Barney E. Klamecki
Keyword(s):  
Room Temperature ◽  
Mechanical Characteristics ◽  
Experimental Studies ◽  
Magnetic Treatment ◽  
The Other ◽  
Thin Wall ◽  
Qualitative Explanation ◽  
The Difference ◽  
And Performance ◽  
And Control

The use of magnetic fields to treat manufactured parts is attractive since easy-to-produce, easy-to-control fields can be used at room temperature, in contrast to more complex treatments such as heat treatment. Little research has been done to apply magnetic treatment to the modification and control of mechanical properties, behavior and performance of manufactured parts. This paper contains descriptions of experimental studies of the effects of pulsed magnetic treatment on the residual stress in machined surfaces and in welded thin-wall tubes, and includes a qualitative explanation of some of the results in terms of dislocation density. The machined part results indicated only possibly small effects, and so further experiments were done with thin-wall tubes that were expected to be more susceptible to magnetic treatment, and a more sensitive measurement technique was used. The difference in damping of vibration of untreated and pulsed magnetically treated welded tubes was used as a measure of treatment effects. Two significant results are reported. One is that pulsed magnetic treatment increased damping by up to 20%, with smaller effects in most tests. The other result is that damping increased, decreased, increased, and so on, as the length of magnetic treatment was increased.

scholarly journals Amorphization and the Effect of Implanted Ions in Sic

1994 ◽  
Vol 373 ◽  
Author(s):  
L. L. Snead ◽  
S. J. Zinkle
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Volume Change ◽  
Room Temperature ◽  
Threshold Dose ◽  
The Other ◽  
Ion Chemistry ◽  
Transmission Electron ◽  
Ion Species

AbstractThe effects of implanted ion chemistry and displacement damage on the amorphization threshold dose of SiC were studied using cross-section transmission electron microscopy. Room temperature as well as 200 and 400°C irradiations were carried out with 3.6 MeV Fe, 1.8 MeV Cl, 1 MeV He or 0.56 MeV Si ions. The room temperature amorphization threshold dose in irradiated regions well separated from the implanted ions was found to range from 0.3 to 0.5 dpa for the four different ion species. The threshold dose for amorphization in the He, Si and Fe ion-implanted regions was also σ0.3 to 0.5 dpa. On the other hand, the amorphization threshold in the Climplanted region was only about 0.1 dpa. The volume change associated with amorphization was σ17&. No evidence for amorphization was obtained in specimens irradiated at 200 or 400°C.

Effect of SPS processing temperature on the microstructure and properties of a Ti49Al47Cr2Nb2 alloy

2006 ◽  
Vol 980 ◽  
Author(s):  
Alain Couret ◽  
Guy Molénat ◽  
Jean Galy ◽  
Marc Thomas
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
The Other ◽  
Processing Temperature ◽  
Post Mortem ◽  
Tial Alloys ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Limited Creep

AbstractThe sintering of TiAl alloys by the Spar Plasma Sintering (SPS) technique is investigated in the present paper. Compactions are conducted between 1100°C and 1225°C on a Ti49Al47Cr2Nb2 powder. Single phased and lamellar microstructures are generated at low and high temperatures, respectively. The former exhibits enhanced tensile properties at room temperature but at the expense of a limited creep resistance. On the other hand, the latter suffers from a poor ductility.The deformation systems which are activated are determined by post-mortem transmission electron microscopy. The behavior of the single phased-alloy is analyzed in terms of the Hall-Petch law.

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