Electron microscope observations of iron-catalyzed gasification of graphite

1978 ◽  
Vol 36 (1) ◽  
pp. 452-453
Author(s):  
A. Szirmae ◽  
V.U.S. Rao ◽  
R.M. Fisher
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Single Crystal ◽  
Catalytic Effect ◽  
Vacuum Deposition ◽  
Gas Chromatograph ◽  
Small Particles ◽  
Transmission Electron

A well known catalytic effect of transition metals and particularly iron in contack with carbonaceous carbon exposed to oxidizing or hydrogenating atmospheres (02, CO-CO2, H2-H2O) has been investigated by scanning and high voltage transmission electron microscopy in a program aimed at determining the fundamental mechanisms of the gasification reactions. Samples of polycrystalline planchets and single crystal flakes of graphite were reacted at temperatures from 650°to 1100°C in “wet” and “dry” hydrogen . Quantitative electron microscope observations were supplemented by weight loss measurements and continuous gas chromatograph analysis of the CO and CH4, produced. Prior to exposure to the reacting gases, small particles of metallic iron are formed on the surface of single crystal graphite flakes or pressed carbon planchets by vacuum deposition of thin films ranging from 1 Å to 2000 Å in thickness.

Microtexture of shock reaction products of niobium and silica mixtures

1999 ◽  
Vol 14 (7) ◽  
pp. 3169-3174 ◽  
Author(s):  
Reiko Murao ◽  
Masae Kikuchi ◽  
Kiyoto Fukuoka ◽  
Eiji Aoyagi ◽  
Toshiyuki Atou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Shock Compression ◽  
Pressure Range ◽  
Reaction Products ◽  
Small Particles ◽  
Powder Mixtures ◽  
X Ray ◽  
Transmission Electron

Shock compression experiments on powder mixtures of niobium metal and quartz were conducted for the pressure range of 30–40 GPa by a 25-mm single-stage propellant gun. Chemical reaction occurred above 35 GPa, and products were found to be mainly so-called “Cu3Au-type” Nb3Si, which contained a small amount of oxygen. Microtextures of the specimen were examined by scanning and transmission electron microscopy. A field-emission transmission electron microscope was used for energy-dispersive x-ray analysis of microtextures in small particles found in the SiO2 matrix, and various species with different Nb/Si ratio and oxygen content were shown to be produced through the nonequilibrium process of shock compression.

Characterization of spray-pyrolized superconducting YBaCuO thin films on single-crystal MgO by transmission electron microscopy

1990 ◽  
Vol 5 (8) ◽  
pp. 1605-1611 ◽  
Author(s):  
S. J. Golden ◽  
H. Isotalo ◽  
M. Lanham ◽  
J. Mayer ◽  
F. F. Lange ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Film Thickness ◽  
Single Crystal ◽  
Processing Parameters ◽  
Transmission Electron ◽  
Film Substrate ◽  
Mgo Substrate

Superconducting YBaCuO thin films have been fabricated on single-crystal MgO by the spray-pyrolysis of nitrate precursors. The effects on the superconductive behavior of processing parameters such as time and temperature of heat treatment and film thickness were investigated. The superconductive behavior was found to be strongly dependent on film thickness. Films of thickness 1 μm were found to have a Tc of 67 K while thinner films showed appreciably degraded properties. Transmission electron microscopy studies have shown that the heat treatments necessary for the formation of the superconductive phase (for example, 950 °C for 30 min) also cause a substantial degree of film-substrate interdiffusion. Diffusion distances for Cu in the MgO substrate and Mg in the film were found to be sufficient to explain the degradation of the superconductive behavior in films of thickness 0.5 μm and 0.2 μm. From the concentration profiles obtained by EDS analysis diffusion coefficients at 950 °C for Mg into the YBaCuO thin film and for Cu into the MgO substrate were evaluated as 3 × 10−19 m2/s and 1 × 10−17 m2/s, respectively.

Annealing Effects in Ten Films of Thoria

1968 ◽  
Vol 26 ◽  
pp. 392-393
Author(s):  
S. E. Bronisz ◽  
Dana L. Douglass
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
Electron Microscope ◽  
Single Crystals ◽  
Crystalline Materials ◽  
Transmission Electron ◽  
Annealing Effects ◽  
Diffraction Effects

Thin films of thoria, either cleaved from air-fired material or vacuum deposited on polished copper substrates, were examined by transmission electron microscopy. As prepared, the two types of samples were considerably different, but after being heated in the electron microscope they were closely similar.The cleaved samples were obtained by means of extraction replication of fracture surfaces of polycrystalline thoria. The thin flakes ranged from about 0.1 to 20 μm in diameter. Most of them were single crystals exhibiting the diffraction effects expected of crystalline materials and containing many long dislocations. Upon heating with the unapertured electron beam the dislocations disappeared, the crystals became more electron transparent, and the striated microstructure shown in Fig. 1 developed. The orientations of most of the cleaved crystals were equally divided among ﹛110﹜, ﹛111﹜, and ﹛112﹜. The striae were usually parallel to <110> or <135>.

DEFECTS OF A15 SMALL PARTICLES IN TUNGSTEN THIN FILMS

1996 ◽  
Vol 03 (01) ◽  
pp. 1191-1194 ◽  
Author(s):  
MASASHI ARITA ◽  
ISAO NISHIDA
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Crystal Defects ◽  
Type Structure ◽  
Special Structure ◽  
Small Particles ◽  
Structure Unit ◽  
Transmission Electron ◽  
Means Of Transmission

Crystal defects of A15 small particles in tungsten thin films were studied by means of transmission electron microscopy. Defects found in nanoscale crystals were analyzed to have special structure containing the Zr4Al3-type structure unit.

Interactions Of Evaporated Nickel And Silicon Thin Films

1985 ◽  
Vol 54 ◽  
Author(s):  
L. R. Zheng ◽  
L. S. Hung ◽  
J. W. Mayer
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Single Crystal ◽  
Formation Temperature ◽  
Si Substrates ◽  
Silicon Thin Films ◽  
Transmission Electron ◽  
Amorphous Si ◽  
The Stability

ABSTRACTInteractions of evaporated Ni and Si thin films were investigated by a combination of backseat tering spectrometry and transmission electron microscopy. The presence of amorphous Si has no significant effects on Ni2Si and NiSi formation, but it drastically lowers the formation temperature of NiSi. Experiments with evaporated thin markers established that Ni is the dominant diffusing species in the growth of the three suicides. The stability of NiSi was examined by sequential evaporation of Ni34Si66 and Ni50Si50 thin films both on Si(100) and on evaporated Si substrates. The results showed that NiSi2 grows at the expence of NiSi when the stucture is in contact with evaporated Si, while it dissociates into NiSi and Si when in contact with single crystal Si.

Detection and Measurement of Intermetallic Thin Films Using EDX Line Scanning

2015 ◽  
Author(s):  
Carl Nail
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
Electron Microscope ◽  
Tem Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Line Scanning ◽  
Scanning Electron

Abstract Elementally characterizing intermetallic compounds (IMCs) to identify phases has routinely required relatively expensive transmission electron microscopy (TEM) analysis. A study was done characterizing IMCs using less expensive energydispersive x-ray (EDX) spectroscopy tools to investigate it as a practical alternative to TEM. The study found that EDX line scanning can differentiate phases by tracking changes in count rate as the electron beam of a scanning electron microscope (SEM) passes from one phase to another.

The Morphology of YBa2Cu3O7−x Thin Films Grown on Ceramic Substrates

1987 ◽  
Vol 99 ◽  
Author(s):  
L. A. Tietz ◽  
B. C. De Cooman ◽  
C. B. Carter ◽  
D. K. Lathrop ◽  
S. E. Russek ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Single Crystal ◽  
Ion Beam ◽  
Substrate Surface ◽  
The Other ◽  
Ceramic Substrates ◽  
Transmission Electron ◽  
Beam Damage

ABSTRACTThe microstructure of thin films of the high Tc superconductor YBa2Cu3O7−x deposited on SrTiO3 and Y-stabilized cubic-zirconia (YSZ) single-crystal substrates has been characterized by transmission electron microscopy. Films on both substrates were polycrystalline. On {001 }-oriented SrTiO3, the grains are oriented with <110> normal to the substrate surface. On the same orientation of YSZ, two microstructures are observed: one in which grains have their c-axes normal to the substrate surface, the other in which grains have the a- (or b-) axis normal to the substrate surface. Both of these microstructures contain special grain boundaries. Annealing of ion-milled TEM specimens is presented as a means of removing ion-beam damage.

Phenomena Associated with Oxygen in Titanium

1967 ◽  
Vol 25 ◽  
pp. 310-311
Author(s):  
E. U. Lee ◽  
P. A. Garner ◽  
J. S. Owens
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Microstructural Changes ◽  
Electrolytic Polishing ◽  
Interstitial Impurities ◽  
Thin Foils ◽  
Transmission Electron ◽  
Iodide Titanium ◽  
Alpha Titanium

Evidence for ordering (1-6) of interstitial impurities (O and C) has been obtained in b.c.c. metals, such as niobium and tantalum. In this paper we report the atomic and microstructural changes in an oxygenated c.p.h. metal (alpha titanium) as observed by transmission electron microscopy and diffraction.Oxygen was introduced into zone-refined iodide titanium sheets of 0.005 in. thickness in an atmosphere of oxygen and argon at 650°C, homogenized at 800°C and furnace-cooled in argon. Subsequently, thin foils were prepared by electrolytic polishing and examined in a JEM-7 electron microscope, operated at 100 KV.

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