Synthesis of intermetallic NiAl and Ni3Al fine powders through organometallic precursors

1991 ◽  
Vol 6 (5) ◽  
pp. 928-934 ◽  
Author(s):  
Osami Abe ◽  
Akira Tsuge
Keyword(s):  
Heat Treatment ◽  
Thermal Decomposition ◽  
Particle Size ◽  
Aqueous Solutions ◽  
Single Phase ◽  
Initial Step ◽  
The Other ◽  
Fine Powders ◽  
Organometallic Precursors ◽  
Step Heat Treatment

Fine powders of intermetallic NiAl and Ni3Al were synthesized through organometallic precursors, which were coprecipitated from aqueous solutions of NiCl2 and AlCl3 by the addition of ammonium benzoate and hydradinium monochloride as precipitants. Ni3Al and NiAl were synthesized by a two-step heat treatment of the precursors. The initial step was the thermal decomposition of organic groups to form homogeneous mixtures of Ni3C, amorphous Al2O3, and free C below 1000 °C. The other step was the reaction above 1300 °C to form the intermetallics. Single phase powders of NiAl and Ni3Al with the particle size less than 3 μm were obtained above 1300 and 1400 °C, respectively.

Quantitative Determimatioh of Sulfur, Chlorine, Potassium, Calcium, Scandium and Titanium in Aqueous Solutions by Radioisotopic Excited Fluorescent Spectrometer and by Conventional X-Ray Spectrometer

1970 ◽  
Vol 14 ◽  
pp. 102-126 ◽  
Author(s):  
Frank L. Chan ◽  
W. Barclay Jones
Keyword(s):  
Particle Size ◽  
Aqueous Solutions ◽  
Experimental Results ◽  
The Other ◽  
X Rays ◽  
Helium Atmosphere ◽  
X Ray ◽  
Effect Of Particle Size ◽  
The One

AbstractAn x-ray spectrometer with experimental results is herewith described using a radiosotope source Fe55 having a halflife of 2.6 years. As a result of the disintegration, the managanese x-rays are capable of exciting fluorescent x-rays of such elements as sulfur, chlorine, potassium, calcium, scandium and titanium in aqueous solutions. These elements with the Ka wavelengths ranging from 5.3729 Å to 2.7496 Å may be designated as between the very soft x-rays on the one hand and the hard x-rays on the other. The x-ray spectrometer presently described has achieved a resolution of 136 ev, FWHM.Simultaneously, these elements have also been quantitatively determined by conventional x-ray fluorescent spectrometers. Since one of the spectrometers is designed to operate in vacuum as well as in helium or air, determination of sulfur, potassium and calcium were carried out in vacuum. Determination of chlorine was carried out in a helium atmosphere, Calcium, scandium and titanium were determined in air with an air-path spectrometer.In the present study aqueous solutions containing these elements were used. The use of aqueous solutions has the inherent advantages of being homogeneous and free from effect of particle size.

Effect of Ausageing on the Precipitation Behavior of MX Carbonitride in Modified 9Cr-1Mo Steel

2007 ◽  
Vol 539-543 ◽  
pp. 2976-2981
Author(s):  
Masataka Yoshino ◽  
Yoshinao Mishima ◽  
Yoshiaki Toda ◽  
Hideaki Kushima ◽  
Kota Sawada ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Single Phase ◽  
Equilibrium Phase ◽  
The Other ◽  
Austenite Matrix ◽  
Precipitation Behavior ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
The Matrix ◽  
Equilibrium Mole Fraction

The precipitation behavior of MX carbonitride during a normalizing heat treatment with and without ausageing was investigated in a modified 9Cr-1Mo steel. The normalizing heat treatment was performed at 1150 oC for 1800 s. Ausageing was conducted at 765 and 500 oC for 1800 to 86400 s during the cooling from the heat treatment. The matrix of the steel was austenite single phase during normalizing and ausageing, except for that ausaged at 765 oC for 86400 s. The initial austenite grain size and hardness were not influenced by ausageing, except for the sample ausaged at 765 oC for 86400 s. Although Nb-rich MX (NbX) and cementite were observed, V-rich MX (VX) was not observed under any of the conditions investigated. The amount of NbX in the steel ausaged at 500 oC was at least twice as large as that under the other conditions, and the amount in the steel ausaged at 760 oC was slightly larger than that in the steel that did not undergo ausageing. The precipitation of NbX took place during ausageing in the austenite matrix. On the other hand, it is well known that VX precipitates during tempering. An equilibrium mole fraction of VX in the austenite matrix calculated by Thermo-Calc. was larger than that of NbX at the ausageing temperatures. It is proposed that VX is an equilibrium phase at the ausageing temperature; however, VX nucleation takes much longer in the austenite matrix. It is postulated that the precipitation of VX is more strongly influenced by the interfacial energy rather than supersaturation. It is concluded that the precipitation of MX carbonitride, especially NbX, can be controlled by ausageing during cooling after a normalizing heat treatment.

Effect of Heat Treatment on Chemical Structure of a Bio-Filler from Vetiver Grass

2011 ◽  
Vol 410 ◽  
pp. 71-74 ◽  
Author(s):  
Wimonlak Sutapun ◽  
Yupaporn Ruksakulpiwat ◽  
Nitinat Suppakarn
Keyword(s):  
Heat Treatment ◽  
Thermal Decomposition ◽  
Particle Size ◽  
Crystalline Structure ◽  
Chemical Structure ◽  
Fiber Surface ◽  
Thermogravimetric Analyzer ◽  
Heat Treated ◽  
Particle Size Analyzer ◽  
Ftir Spectrometer

In this work, the effect of heat treatment on chemical and crystalline structure of vetiver powder was studied. The vetiver powder was heat treated at 170°C, the temperature below thermal decomposition of hemicellulose, for 2-6 hours. The chemical structure, crystalline structure, and thermal decomposition of untreated and heat-treated vetiver were examined via FTIR spectrometer X-ray diffractometer, and thermogravimetric analyzer, respectively. In addition, the particle size and size distribution, fiber surface, and specific surface area were investigated by particle size analyzer, scanning electron microscope, and BET surface analyzer, repectively. It was founded that some waxes, lignin, and hemicellulose were removed by the thermal treatment. This resulted in smaller particle size of heat-treated vetivers. In addition, moisture content was minimized from 7 to 4 wt% by the treatment. However, removal of those compositions did not influence crystal structure of cellulose and surface functional groups of heat-treated vetiver.

Microwave Preparation of Mullite Powders

1988 ◽  
Vol 124 ◽  
Author(s):  
Sridhar Komarneni ◽  
Else Breval ◽  
Rustum Roy
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Microwave Heating ◽  
Single Phase ◽  
Processing Parameters ◽  
Microwave Processing ◽  
Microwave Oven ◽  
Fine Powders ◽  
Diphasic Gels

ABSTRACTMullite, Al6Si2O13 composition gels were made by the single phase and diphasic routes. The wet mullite gels were heated in the insulated cavity of an ordinary kitchen microwave oven (2.45 GHz; 700 watts). Crystalline mullite powders were obtained from single phase gels while the diphasic gels yielded α-Al2O3 and mullite in a matter of 20–25 minutes of microwave heating. Trans- mission electron microscopy showed that the mullite particle size varied between 50 nm to 1 μm. The results of this study suggest that fine powders of mullite can be obtained from single phase mullite gels by optimizing the microwave processing parameters.

The Influence of Thermal Treatment on Defect Characteristics in Cz-Silicon Wafers Investigated by Positron Annihilation Spectroscopy

1992 ◽  
Vol 262 ◽  
Author(s):  
P. Mascher ◽  
W. Puff ◽  
S. Hahn ◽  
K. H. Cno ◽  
B. Y. Lee
Keyword(s):  
Heat Treatment ◽  
Fourier Transform ◽  
Positron Lifetime ◽  
Positron Annihilation Spectroscopy ◽  
Silicon Wafers ◽  
The Other ◽  
Doppler Broadening ◽  
Bulk Silicon ◽  
Distinctive Difference ◽  
Step Heat Treatment

ABSTRACTPositron lifetime and Doppler-broadening experiments as well as Fourier-transform infrared spectroscopy (FTIR) were performed on a variety of six-inch Czochralski (CZ) silicon wafers. Measurements were done at 14 equidistant locations across the wafers which were cut from the seed-, middle-, and tail-sections of two boules grown at different pull-speeds.In the as-grown wafers, the positron response consisted of components from small oxygen-related clusters and “perfect” bulk silicon only. Possible contributions from vacancy-type defects were at or just below the detection limit. After a two-step heat treatment (750°C/ 4 hrs + 1050°C/6 hrs in N2) FTIR showed that significant amounts of oxygen (4–8 ppma) had precipitated in wafers taken from the seed-sections of the boules but not in any of the other wafers. The positron data did not reflect this distinctive difference, however, both lifetime and Doppler-broadening results strongly indicate the creation of vacancy-type defects at concentrations in the 1016cm−3-range.

Effect of MCl (M = Na, K) addition on microstructure and electrical conductivity of forsterite

2020 ◽  
Vol 92 (1) ◽  
pp. 10901
Author(s):  
Saloua El Asri ◽  
Hamid Ahamdane ◽  
Lahoucine Hajji ◽  
Mohamed El Hadri ◽  
Moulay Ahmed El Idrissi Raghni ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Electrical Conductivity ◽  
Single Phase ◽  
Sol Gel ◽  
Complex Impedance ◽  
Transmission Spectra ◽  
Electrical Measurements ◽  
Cation Type ◽  
Edx Analyses ◽  
The Fourier Transform

Forsterite single phase powder Mg2SiO4 was synthesized by sol–gel method alongside with heat treatment, using two different cation alkaline salts MCl as mineralizers (M = Na, K) with various mass percentages (2.5, 5, 7.5, and 10 wt.%). In this work, we report on the effect of the cation type and the added amount of used mineralizer on microstructure and electrical conductivity of Mg2SiO4. The formation of forsterite started at 680–740  °C and at 630–700  °C with KCl and NaCl respectively, as shown by TG-DTA and confirmed by XRD. Furthermore, the Fourier transform infrared (FTIR) transmission spectra indicated bands corresponding to vibrations of forsterite structure. The morphology and elemental composition of sintered ceramics were examined by SEM-EDX analyses, while their densities, which were measured by Archimedes method, increased with addition of both alkaline salts. The electrical measurements were performed by Complex Impedance Spectroscopy. The results showed that electrical conductivity increased with the addition of both mineralizers, which was higher for samples prepared with NaCl than those prepared with KCl.

Eurasian "Theory of Economy Management" as an Organic Part of the Russian Economic School

2003 ◽  
pp. 95-110
Author(s):  
M. Voeykov
Keyword(s):  
Economic Development ◽  
Theoretical Model ◽  
Initial Step ◽  
State Regulation ◽  
Soviet Economy ◽  
The Other ◽  
Large Share ◽  
Organic Part ◽  
Two Sides ◽  
Enterprise Activity

The original version of "the theory of economy management", developed in the 1920s by Russian economists-emigrants who called themselves "Eurasians" (N. Trubetskoy, P. Savitskiy, etc.) is analyzed in the article. They considered this theory to be the basis of the original Russia's way of economic development. The Eurasian theory of economy management focuses on two sides of enterprise activity: managerial as well as social and moral. The Eurasians accepted the Soviet economy with the large share of state regulation as the initial step of development. On the other hand they paid much attention to the private sector activity. Eurasians developed a theoretical model of the mixed economy which can be attributed as the Russian economic school.

Disinfection of Fruits with Activated Water

2019 ◽  
Vol 10 ◽  
pp. 1864-1872
Author(s):  
Prof. Teodora P. Popova
Keyword(s):  
Antimicrobial Activity ◽  
Aqueous Solutions ◽  
Antimicrobial Properties ◽  
The Other ◽  
Gram Negative Bacteria ◽  
High Antimicrobial Activity ◽  
Gram Negative ◽  
E Coli ◽  
Number Of Microorganisms ◽  
Lower Effect

The effect of ionized aqueous solutions (anolytes and catholyte) in the processing of fruits (cherries, morellos, and strawberries) for decontamination has been tested. Freshly prepared analytes and catholyte without the addition of salts were used, as well as stored for 7 months anolytes, prepared with 0.5% NaCl and a combination of 0.5% NaCl and 0.5% Na2CO3. The anolyte prepared with a combination of 0.5% NaCl and 0.5% Na2CO3, as well as the anolyte obtained with 0.5% NaCl, exhibit high antimicrobial activity against the surface microflora of strawberries, cherries, and sour cherries. They inactivate E. coli for 15 minutes. The other species of the fam. Enterobacteriaceae were also affected to the maximum extent, as is the total number of microorganisms, especially in cherries and sour cherries. Even stored for 7 months, they largely retain their antimicrobial properties. Anolyte and catholyte, obtained without the addition of salts, showed a lower effect on the total number of microorganisms, but had a significant effect on Gram-negative bacteria, and especially with regard to the sanitary indicative E. coli.

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