X-ray diffraction investigation of the alloy formation process in the products of reduction of tungsten and molybdenum from a complex oxide

1983 ◽  
Vol 22 (7) ◽  
pp. 528-530
Author(s):  
V. V. Skorokhod ◽  
Yu. M. Solonin
Keyword(s):  
Formation Process ◽  
Complex Oxide ◽  
Alloy Formation ◽  
X Ray Diffraction ◽  
X Ray

Control by Mixed-Chloride Additives of the Quality and Homogeneity of Bulk Halide Perovskite upon Film Formation Process

2021 ◽  
Author(s):  
Thierry Pauporté ◽  
Daming zheng
Keyword(s):  
Solar Cells ◽  
Formation Process ◽  
High Efficiency ◽  
Film Formation ◽  
Perovskite Solar Cells ◽  
X Ray Diffraction ◽  
X Ray ◽  
Stability Issue ◽  
Halide Perovskite ◽  
The Stability

Nowadays, overcoming the stability issue of perovskite solar cells (PSCs) while keeping high efficiency has become an urgent need for the future of this technology. By using x-ray diffraction (XRD),...

Hydrogen and Oxygen Chemisorptions and Titrations by Platinum on Zirconia Catalysts Reduced between 673 and 1273 K

1985 ◽  
Vol 2 (2) ◽  
pp. 55-68 ◽  
Author(s):  
L. Tournayan ◽  
A. Auroux ◽  
H. Charcosset ◽  
R. Szymanski
Keyword(s):  
Surface Composition ◽  
Pt Catalyst ◽  
Hydrogen Chemisorption ◽  
Alloy Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxygen Chemisorption ◽  
Alloy Particles ◽  
Frontal Method ◽  
The Mean

Some 10 wt % Pt supported on zirconia catalysts were investigated by hydrogen and oxygen chemisorptions and titrations by means of automated catharometric equipment (frontal method). Microcalorimetry was further used to determine the heats of oxygen chemisorption. The temperature of reduction by hydrogen, TR, was varied between 673 and 1273 K. At 673 K, the H and O coverages of Pt were about the same as for Pt supported on SiO2 (Euro Pt catalyst). The increase in TR from 673 to 873 K was accompanied by a strong decrease of the hydrogen to oxygen chemisorption ratio. It is proposed that this is due to Pt1– xZr x alloy formation, with small values of x (≤0·05). When TR was above 873 K, x determined by X-ray diffraction analysis increased up to 0·25. The hydrogen chemisorption is confined to Pt s, while the oxygen chemisorption takes place on Pt s and Zr sO x. The surface composition may be derived and is found twice as rich in Zr as the mean composition of the alloy particles.

The Oxide Scale Growth Mechanism on Fe20Cr5Al+RE Alloy in SO2+O2

2009 ◽  
Vol 289-292 ◽  
pp. 541-550 ◽  
Author(s):  
Jerzy Jedlinski ◽  
Zbigniew Żurek ◽  
Martah Homa ◽  
G. Smoła ◽  
J. Camra
Keyword(s):  
Phase Composition ◽  
Secondary Ion Mass Spectrometry ◽  
Grazing Angle ◽  
Oxidation Mechanism ◽  
Complex Oxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thin Foils ◽  
Manufacturing Procedure ◽  
Secondary Ion

The oxidation mechanism of FeCrAl (+RE), RE: reactive elements: Y and Hf) thin foils was studied at temperatures ranging from 1093 K to 1173 K in SO2+1%O2 atmosphere. Materials were subjected to isothermal and thermal cycling exposures as well as to the so-called two-stage-oxidation. In the latter, an oxygen isotope 18O2 was used as a tracer. Starting materials and scales were characterized using Grazing Angle X-Ray Diffraction (GA-XRD), EDX, SEM, XPS and High Spatial Resolution Secondary Ion Mass Spectrometry (HSR-SIMS). The obtained results showed within the studied range of exposure conditions the scales on all the studied alloys grow via outward mechanism typical for transient oxides and not for the -Al2O3 which is consistent with phase composition results and scale morphology and/or microstructure. It was also found that ‘as received’ foils are not bare metals but complex oxide-on-metal systems resulting from their manufacturing procedure. The obtained results are discussed in terms of the diffusion-related transport properties of the scale and of the scale phase composition.

SYNTHESIS AND CHARACTERIZATION OF NANOCRYSTALLINE FeNi AND Ni3Fe ALLOYS

2011 ◽  
Vol 25 (07) ◽  
pp. 1013-1019 ◽  
Author(s):  
S. AZADEHRANJBAR ◽  
F. KARIMZADEH ◽  
M. H. ENAYATI
Keyword(s):  
Ball Mill ◽  
Morphological Evolution ◽  
Lattice Parameter ◽  
Internal Stresses ◽  
Alloy Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Particles ◽  
Fe Alloys

Nanocrystalline FeNi and Ni 3 Fe alloys were prepared by mechanical alloying of Fe and Ni elemental powders using a planetary ball mill under protection atmosphere. X-ray diffraction measurements were performed to follow alloy formation process in these alloys. A heat treatment of 1 h at 800°C was carried out to relax the internal stresses of the milled samples. Morphological evolution of powder particles was revealed by scanning electron microscopy. The value of lattice parameter was reached to 0.35762 nm and the hardness was found to be 686 HV at 30 h milled FeNi powder. In the case of Ni 3 Fe the values of 0.3554 nm and 720 HV were obtained for lattice parameter and hardness, respectively.

X-ray microdiffraction study of the half-V-shaped switching liquid crystal

2004 ◽  
Vol 19 (1) ◽  
pp. 53-55 ◽  
Author(s):  
Kazuhiro Takada ◽  
Takashi Noma ◽  
Takeshi Togano ◽  
Taihei Mukaide ◽  
Atsuo Iida
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Formation Process ◽  
Ferroelectric Liquid Crystal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transient Layer ◽  
Smectic C ◽  
Layer Structures ◽  
Temperature Controlled

Local layer structures and their formation process in a half-V-shaped switching ferroelectric liquid crystal (HV-FLC) were investigated by means of synchrotron X-ray microdiffraction. The HV-FLC is a FLC that has a cholesteric–chiral smectic C (Ch–SmC*) phase transition sequences. X-ray microdiffraction measurements revealed that the SmC* phase in the HV-FLC was composed of asymmetric chevron and inclined-bookshelf structures. In addition, temperature-controlled X-ray diffraction measurements showed that the transient layer structures appeared during the Ch to SmC* phase transition.

In Situ Time-Resolved X-Ray Diffraction of Tobermorite Formation Process Under Autoclave Condition

2010 ◽  
Vol 93 (9) ◽  
pp. 2667-2674 ◽  
Author(s):  
Jun Kikuma ◽  
Masamichi Tsunashima ◽  
Tetsuji Ishikawa ◽  
Shin-Ya Matsuno ◽  
Akihiro Ogawa ◽  
...  
Keyword(s):  
Formation Process ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray

Synthesis of PbTe Intermetalic Compound by Mechanical Alloying

2010 ◽  
Vol 660-661 ◽  
pp. 347-352 ◽  
Author(s):  
Y.A. Chen ◽  
Cosme Roberto Moreira Silva ◽  
D. Michael Rowe
Keyword(s):  
Mechanical Alloying ◽  
Critical Mass ◽  
Alloy Formation ◽  
X Ray Diffraction ◽  
Pure Lead ◽  
X Ray ◽  
Sieve Size ◽  
Profile Fitting ◽  
Lower Charge ◽  
Hardened Tool Steel

The formation of PbTe intermetallic compound by mechanical alloying (MA) has been investigated. The elemental starting materials were 99.5% pure lead and tellurium, with a sieve size of 80 and 200 mesh, respectively. A SPEX 8000 shaker milling was used to perform the MA, using WC balls as milling media in a cylindrical hardened tool steel vial. X-ray diffraction analysis was performed with a profile-fitting program, to evaluate time evolution of the alloy formation. An exotermical reaction occurs on PbTe formation, with entalphy H= - 16.3 Kcal/mol. The *T value is confirmed by the heat exchange equation *Q = |*Hf | =* i (mici ) *T, where the summation comprises the mass and specific heat of vial, balls and powder material. For the standard milling conditions employed, the PbTe formation occurs at aproximately 90 seconds of milling, when using charge ratios between 3:1 and 7.5:1. However, for lower charge ratios (8:1 to 10:1), isolated reactions at the mixture occurs, but the amount of material is not enough to raise the temperature of adjacent regions, and the propagation of the reaction is avoided. There is therefore a minimum amount of powder (“critical mass”), and below this value the reaction will not be self-sustained.

Synthesis of Ultrafine Cr3C2 Powders by Carbothermal Reduction of Precursors

2012 ◽  
Vol 549 ◽  
pp. 310-313
Author(s):  
Yong Zhong Jin ◽  
Fa Ming Ye ◽  
Chun Hai Liu ◽  
Rui Song Yang
Keyword(s):  
Electron Microscopy ◽  
Carbothermal Reduction ◽  
Complex Oxide ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
Precursor Method ◽  
Air Drying ◽  
X Ray ◽  
Homogeneous Chemical ◽  
Scanning Electron

Ultrafine Cr3C2 powders with globular-like particle of ~0.3-0.8 μm were synthesized by a new precursor method, namely carbothermal reduction of complex chromium oxide-carbon mixture, which was made initially from salt solution containing chromium and carbon elements by air drying and subsequent calcining at 400 °C for 1 h. Phase composition of reaction products was discussed by X-ray diffraction (XRD), and microstructure of the calcined powders and final products was studied by scanning electron microscopy (SEM). The results show that the synthesizing temperature of Cr3C2 powders was reduced greatly by the new precursor method. Thus, the preparation of ultrafine Cr3C2 powders is at only 1000 °C for 2 h. The lowering of synthesizing temperature is mainly due to the homogeneous chemical composition of the complex oxide-carbon mixture. There is a coarsening tendency of Cr3C2 powders with the increase of reaction temperature and time.

Effect of Gallium and Indium Co-Substituting on Upconversion Properties of Er/Yb:Yttrium Aluminum Garnet Powders Prepared by the Co-Precipitation Method

2016 ◽  
Vol 16 (4) ◽  
pp. 3517-3521 ◽  
Author(s):  
Wei Zhang ◽  
Yun-Ling Liang ◽  
Zheng-Fa Hu ◽  
Zu-Yong Feng ◽  
Ma Lun ◽  
...  
Keyword(s):  
Emission Spectrum ◽  
Infrared Spectra ◽  
Formation Process ◽  
Photoelectron Spectroscopy ◽  
Blue Shift ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermo Gravimetry ◽  
Co Precipitation

Gallium and Indium co-substituted Yb, Er:YAG was fabricated through the chemical co-precipitation method. The formation process and structure of the Ga3+ and In3+ substituted phosphor powders were characterized by the X-ray diffraction, thermo-gravimetry analyzer, infrared spectra, and X-ray photoelectron spectroscopy, and the effects of Ga3+ and In3+ concentration on the luminescence properties were investigated by spectrum. The results showed that the blue shift occurred after the substitution of Ga3+ and In3+ for Al3+ in matrix, and the intensity of emission spectrum was affected by the concentration of Ga3+ and In3+.

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