Comments on the paper `The application of a glancing-angle X-ray diffraction film technique to the study of the low-temperature oxidation of iron-chromium alloys'

1968 ◽  
Vol 1 (3) ◽  
pp. 387-389 ◽  
Author(s):  
R J Pearce ◽  
W R Price
Keyword(s):  
Low Temperature ◽  
X Ray Diffraction ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
X Ray ◽  
Chromium Alloys ◽  
Glancing Angle ◽  
Iron Chromium

STUDY OF MICROSTRUCTURE AND CATALYTIC ACTIVITY OF γ-Bi2MoO6 AND Bi2WO6 COMPOUNDS

2002 ◽  
Vol 09 (05n06) ◽  
pp. 1779-1783 ◽  
Author(s):  
R. RANGEL ◽  
P. BARTOLO-PÉREZ ◽  
A. GÓMEZ-CORTÉZ ◽  
G. DÍAZ ◽  
D. H. GALVÁN
Keyword(s):  
Catalytic Activity ◽  
Structural Changes ◽  
Potential Candidate ◽  
Nitrogen Absorption ◽  
X Ray Diffraction ◽  
Low Temperature Oxidation ◽  
Auger Analysis ◽  
Temperature Oxidation ◽  
X Ray ◽  
Lower Temperature

Bi 2 MO 6 (M=Mo, W) compounds were prepared for low-temperature oxidation. The catalysts were prepared by solid-state reaction. The structural changes were followed by X-ray diffraction, scanning electron microscopy, Auger electron spectroscopy and BET nitrogen absorption. Auger analysis shows that Bi 2 WO 6 catalysts have more bismuth on the surface than γ- Bi 2 MoO 6, although both samples are bismuth deficient as compared to the stoichiometric compound. The results regarding catalytic activity show that Bi 2 WO 6 prepared at 1073 K reaches total conversion of CO (100%) at a lower temperature when compared to γ- Bi 2 MoO 6. This indicates that Bi 2 WO 6 is a potential candidate to be used as catalyst in the CO to CO 2 oxidation.

Nucleation and growth of iron oxides in olivines, (Mg,Fe)2SiO4

1970 ◽  
Vol 37 (291) ◽  
pp. 790-800 ◽  
Author(s):  
P. E. Champness
Keyword(s):  
Electron Microscopy ◽  
Iron Oxide ◽  
Amorphous Silica ◽  
Nucleation And Growth ◽  
X Ray Diffraction ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
X Ray ◽  
The Matrix ◽  
Equiaxed Grains

SummaryIron-rich olivines have been oxidized in air in the laboratory and the mechanism of their breakdown has been elucidated using X-ray diffraction and electron microscopy. Low-temperature oxidation (500–800 °C) produces well-oriented hematite- and magnetite-like precipitates together with amorphous silica. The reaction is a cellular one in which thin needles of oxide about 50–100 Å apart grow into the matrix separated by regions of amorphous silica. Nucleation of spherical colonies of the iron oxide and silica occurs on dislocations.Although the hematite or magnetite always shows the same topotactic relationship with the matrix, the direction in which the needle-like precipitates grow is determined by the orientation of the nucleating dislocation. The small size and highly distorted nature of these precipitates accounts for the diffuseness of their X-ray reflections.Oxidation at 1000 °C produces undistorted equiaxed grains of the oxides about 0·2 μm in size. They are surrounded by silica, which produces a disordered electron diffraction pattern. As the temperature is raised, the silica achieves more structural order and the oxide grains increase in size.

Low Temperature Oxidation Behaviors of CNTs/MoSi2 Composites

2014 ◽  
Vol 983 ◽  
pp. 116-120
Author(s):  
Houan Zhang ◽  
He Jian Wu ◽  
Jia Lin ◽  
Si Yong Gu ◽  
Lei Yu
Keyword(s):  
Electron Microscopy ◽  
Molybdenum Disilicide ◽  
Phase Identification ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
X Ray ◽  
Scanning Electron ◽  
Oxidation Behaviors

Molybdenum disilicide (MoSi2) matrix composites with various contents of carbon nanotubes (CNTs) were fabricated by sintering in vacuum at 1550 °C for 1 h. The oxidation behaviors of CNTs/MoSi2composites at 400 °C and 500 °C for 200 h in air were studied. Results showed that the weight loss of CNTs/MoSi2composites increased with the increase of CNTs content. “Pest” phenomenon happened at 400 °C but not at 500 °C. Phase identification and microstructure of the samples were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that many MoO3whiskers and microcracks only occurred on the surface of CNTs/MoSi2composites when oxidized at 400 °C in air, which leaded to the catastrophic disintegration of CNTs/MoSi2composites.

Low Temperature Oxidation Processing with High Purity Ozone

1996 ◽  
Vol 429 ◽  
Author(s):  
A. Kurokawa ◽  
S. Ichimura ◽  
H. J. Kang ◽  
D. W. Moon
Keyword(s):  
Low Temperature ◽  
Thermal Oxidation ◽  
High Purity ◽  
Photoelectron Spectroscopy ◽  
Oxide Formation ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
X Ray

AbstractTo lower the temperature of oxide-passivation processing the high- purity ozone (more than 98 mole %) was used instead of usual thermal oxidation. Initial oxide formation on a Si(111) surface with high-purity ozone is investigated by X-ray photoelectron spectroscopy (XPS). From the comparison of the suboxides formed with ozone and oxygen exposures, it is clear that ozone forms less suboxide than oxygen. The oxidation with ozone also proceeds on the hydrogen passivated surface which oxygen molecules do not oxidize.

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