scholarly journals Investigation of selenium compounds as targets for 76,77Br production using protons of energies up to 34 MeV

2017 ◽  
Vol 105 (10) ◽  
Author(s):  
H. Ebrahim Hassan ◽  
Khaled M. El-Azony ◽  
Ahmed Azzam ◽  
Syed M. Qaim
Keyword(s):  
Phase Composition ◽  
X Ray Diffraction ◽  
Selenium Compounds ◽  
X Ray ◽  
Conventional Sintering ◽  
Sintering Method ◽  
Separation Conditions

AbstractSelenium compounds of Zn, Sn and Cu were prepared using a conventional sintering method and the phase composition of each compound was investigated using X-ray diffraction. The compounds prepared were tested under variable irradiation and separation conditions for

Formation of Tricalcium Silicate Prepared by Electric and Microwave Sintering

2010 ◽  
Vol 148-149 ◽  
pp. 1119-1123
Author(s):  
Kai Ke ◽  
Bao Guo Ma ◽  
Xiao Liang Wang ◽  
Xiang Guo Li
Keyword(s):  
Heating Temperature ◽  
Microwave Sintering ◽  
Electric Heating ◽  
Tricalcium Silicate ◽  
Experimental Results ◽  
X Ray Diffraction ◽  
X Ray ◽  
Conventional Sintering ◽  
Sintering Method

A microwave sintering method was used to prepare C3S from Ca(OH)2, SiO2 and MexOy. f-CaO assay, X-ray diffraction and SEM were used to characterize the sintered samples.The results indicated that ion oxides played a very important role in C3S formation in conventional sintering, the use of MexOy as an additive was so effective in promoting C3S formation. The experimental results showed that samples were heated at an electric heating temperature(1500°C) and then further sintered with microwave for 30~60 min, tricalcium silicate could be formed with kilogram step. The new burning technique can greatly increase the forming speed of tricalcium silicate, MnO2, CuO and Ni2O3 could enhance the microwave sintering.

scholarly journals Synthesis of Cu-CNTs nanocomposites via double pressing double sintering method

2018 ◽  
Vol 23 (4) ◽  
pp. 319-334 ◽  
Author(s):  
Marjan Darabi ◽  
Masoud Rajabi
Keyword(s):  
Electrical Conductivity ◽  
Ball Mill ◽  
Bending Strength ◽  
Sintering Process ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Conventional Sintering ◽  
Cold Pressed ◽  
Sintering Method

In this research, copper (Cu)-carbon nanotubes (CNTs) nanocomposites were synthesized with different weight percentages of CNTs by double pressing double sintering (DPDS) method as well as conventional sintering method. A planetary ball mill was used to disperse CNTs in Cu matrix. The milled powders were first cold pressed to 450 MPa in a uniaxial stainless-steel die with cylindrical compacts (diameter: 12 mm and height: 5 mm). The effect of CNTs content and the DPDS method on the properties of the nanocomposites were investigated. The microstructure and phase analysis of Cu-CNTs nanocomposite samples were studied by FESEM and X-Ray Diffraction. The electrical conductivity of nanocomposites was measured and compared to both sintering methods. Mechanical properties of Cu-CNTs nanocomposites were characterized using bending strength and micro-hardness measurements. Enhancements of about 32% in bending strength, 31.6% in hardness and 19.5% in electrical conductivity of Cu-1 wt.% CNTs nanocomposite synthesized by DPDS method were observed as compared to Cu-1 wt.% CNTs nanocomposites fabricated under the similar condition by a conventional sintering process.

Control of the phase composition of advanced calcium phosphates using an x-ray diffractometer with a curved position-sensitive detector

2020 ◽  
Vol 86 (6) ◽  
pp. 29-35
Author(s):  
V. P. Sirotinkin ◽  
O. V. Baranov ◽  
A. Yu. Fedotov ◽  
S. M. Barinov
Keyword(s):  
Phase Composition ◽  
Calcium Phosphates ◽  
Position Sensitive Detector ◽  
Sensitive Detector ◽  
X Ray Diffraction ◽  
X Ray ◽  
Impurity Phases ◽  
Position Sensitive ◽  
Diffraction Peaks ◽  
Diffraction Patterns

The results of studying the phase composition of advanced calcium phosphates Ca10(PO4)6(OH)2, β-Ca3(PO4)2, α-Ca3(PO4)2, CaHPO4 · 2H2O, Ca8(HPO4)2(PO4)4 · 5H2O using an x-ray diffractometer with a curved position-sensitive detector are presented. Optimal experimental conditions (angular positions of the x-ray tube and detector, size of the slits, exposure time) were determined with allowance for possible formation of the impurity phases during synthesis. The construction features of diffractometers with a position-sensitive detector affecting the profile characteristics of x-ray diffraction peaks are considered. The composition for calibration of the diffractometer (a mixture of sodium acetate and yttrium oxide) was determined. Theoretical x-ray diffraction patterns for corresponding calcium phosphates are constructed on the basis of the literature data. These x-ray diffraction patterns were used to determine the phase composition of the advanced calcium phosphates. The features of advanced calcium phosphates, which should be taken into account during the phase analysis, are indicated. The powder of high-temperature form of tricalcium phosphate strongly adsorbs water from the environment. A strong texture is observed on the x-ray diffraction spectra of dicalcium phosphate dihydrate. A rather specific x-ray diffraction pattern of octacalcium phosphate pentahydrate revealed the only one strong peak at small angles. In all cases, significant deviations are observed for the recorded angular positions and relative intensity of the diffraction peaks. The results of the study of experimentally obtained mixtures of calcium phosphate are presented. It is shown that the graphic comparison of experimental x-ray diffraction spectra and pre-recorded spectra of the reference calcium phosphates and possible impurity phases is the most effective method. In this case, there is no need for calibration. When using this method, the total time for analysis of one sample is no more than 10 min.

Formation of nanoscale sodium dodecahydro-closo- dodecaborate Na2[B12H12] on silicate matrix surface

2019 ◽  
Vol 484 (1) ◽  
pp. 41-43
Author(s):  
E. A. Malinina ◽  
V. K. Skachkova ◽  
I. V. Kozerozhets ◽  
V. V. Avdeeva ◽  
L. V. Goeva ◽  
...  
Keyword(s):  
Phase Composition ◽  
Ammonium Salt ◽  
Liquid Glass ◽  
Silicate Matrix ◽  
X Ray Diffraction ◽  
X Ray ◽  
Salt Sample ◽  
Matrix Surface

The method of nanoscaled sodium dodecahydro-closo-dodecaborate Na2[B12H12] synthesis is presented. The composite is heated to 200°C to yield the desired product, forming with the introduction of triethyl- ammonium salt [Et3NH]2[B12H12] into the silicate matrix of a sodium liquid glass. The morphology and phase composition of the synthesized sample are studied through SEM and X-ray diffraction methods, in comparison to those of a standard salt sample Na2[B12H12]. Based on the obtained data, the sample under study is an amorphous composite, on the surface of which nanoscale crystals of Na2[B12H12] form.

Phase composition depth profiles using spatially resolved energy dispersive X-ray diffraction

2004 ◽  
Vol 37 (6) ◽  
pp. 967-976 ◽  
Author(s):  
Andrew C. Jupe ◽  
Stuart R. Stock ◽  
Peter L. Lee ◽  
Nikhila N. Naik ◽  
Kimberly E. Kurtis ◽  
...  
Keyword(s):  
Phase Composition ◽  
Spatial Resolution ◽  
Zinc Coating ◽  
High Energy ◽  
Sulfate Attack ◽  
Energy Dispersive ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spatially Resolved ◽  
Composition Profiles

Spatially resolved energy dispersive X-ray diffraction, using high-energy synchrotron radiation (∼35–80 keV), was used nondestructively to obtain phase composition profiles along the radii of cylindrical cement paste samples to characterize the progress of the chemical changes associated with sulfate attack on the cement. Phase distributions were acquired to depths of ∼4 mm below the specimen surface with sufficient spatial resolution to discern features less than 200 µm thick. The experimental and data analysis methods employed to obtain quantitative composition profiles are described. The spatial resolution that could be achieved is illustrated using data obtained from copper cylinders with a thin zinc coating. The measurements demonstrate that this approach is useful for nondestructively visualizing the sometimes complex transformations that take place during sulfate attack on cement-based materials. These transformations can be spatially related to microstructure as seen by computed microtomography.

Synthesis of CaWO4:(Eu3+,Tb3+) Thin Films by a Two-Step Method at Room Temperature

2013 ◽  
Vol 710 ◽  
pp. 170-173
Author(s):  
Lian Ping Chen ◽  
Yuan Hong Gao
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Phase Composition ◽  
Room Temperature ◽  
Electrochemical Techniques ◽  
Luminescent Properties ◽  
X Ray Diffraction ◽  
Step Method ◽  
X Ray ◽  
Rare Earth Doped

It is hardly possible to obtain rare earth doped CaWO4thin films directly through electrochemical techniques. A two-step method has been proposed to synthesize CaWO4:(Eu3+,Tb3+) thin films at room temperature. X-ray diffraction, energy dispersive X-ray analysis, spectrophotometer were used to characterize their phase, composition and luminescent properties. Results reveal that (Eu3+,Tb3+)-doped CaWO4films have a tetragonal phase. When the ratio of n (Eu)/n (Tb) in the solution is up to 3:1, CaWO4:(Eu3+,Tb3+) thin film will be enriched with Tb element; on the contrary, when the ratio in the solution is lower than 1:4, CaWO4:(Eu3+,Tb3+) thin film will be enriched with Eu element. Under the excitation of 242 nm, sharp emission peaks at 612, 543, 489 and 589 nm have been observed for CaWO4:(Eu3+,Tb3+) thin films.

Microwave Sintering of YSZ Electrolyte Materials for SOFC

2008 ◽  
Vol 368-372 ◽  
pp. 238-240 ◽  
Author(s):  
Xi Tang Wang ◽  
Girish M. Kale
Keyword(s):  
Microwave Sintering ◽  
X Ray Diffraction ◽  
Final Phase ◽  
X Ray ◽  
Microwave Furnace ◽  
Scanning Electron Microcopy ◽  
Conventional Sintering ◽  
Y2o3 Content ◽  
Ysz Electrolyte ◽  
Considerable Enhancement

Microwave sintering behaviors of four different compositions of YSZ electrolyte materials were investigated. The samples were sintered in 2.45GHz microwave furnace. For comparison, conventional sintering was performed at 1821K.The densities of sintered samples showed considerable enhancement in the densification process under the influence of microwave fields. The samples with lower Y2O3 content are easy to sinter. The influence of the composition and sintering methods on the final phase composition and microstructure were investigated by X-ray diffraction and scanning electron microcopy. Finer and more uniform microstructures were observed in the microwave sintered samples comparing to the conventionally sintered samples.

scholarly journals Iterative regularity and parent-offspring growth mold of stable grain array in bismuth silicate micro-crystals

2011 ◽  
Vol 43 (1) ◽  
pp. 105-112
Author(s):  
Z.G. Zhang ◽  
X.F. Wang ◽  
Q.Q. Tian
Keyword(s):  
Environmental Scanning Electron Microscopy ◽  
Morphological Properties ◽  
Environmental Scanning ◽  
X Ray Diffraction ◽  
Bismuth Silicate ◽  
X Ray ◽  
Offspring Growth ◽  
Line Spacing ◽  
Array Structure ◽  
Sintering Method

Bismuth silicate micro-crystals with grain array structure were prepared by sintering method under atmosphere pressure. The samples were characterized for structural and surface morphological properties by X-ray diffraction (XRD) and Environmental scanning electron microscopy (ESEM). The result shows that stable grain arrays grow by iterative mode. If a stable grain array eliminates, a new stable grain array will generate. In a stable parent array, an offspring array may generate after the corresponding partial elimination of its parent array. If one part of an offspring array stops growing, it will be as a new parent array, and then its offspring grain array will create. The sum of the lengths of an offspring array and the corresponding eliminated part of its parent array is equal to the length of the next eliminated part of its parent array. It means the growth rate of an offspring array is equal to that of the corresponding survived part of its parent array. There is a highly correlation between grain array length and average grain line spacing. It means that larger average grain line spacing corresponds to the stable grain array with lager length. When average grain line spacing increases 1?m, the corresponding array length will increase approximately 7.6?m.

Laser Sintering of Greens Compacts of MoSi2

2006 ◽  
Vol 530-531 ◽  
pp. 364-368
Author(s):  
G. de Vasconcelos ◽  
R. Cesar Maia ◽  
Carlos Alberto Alves Cairo ◽  
R. Riva ◽  
N.A.S. Rodrigues ◽  
...  
Keyword(s):  
Cross Section ◽  
Laser Processing ◽  
Single Phase ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heating Source ◽  
Scanning Electron Microcopy ◽  
Conventional Sintering ◽  
Reduced Time

In this study, the results of the feasibility of sintering green compacts of metallic powder of MoSi2 by a CO2 laser beam as the heating source has been investigated. The main advantage of this technique is to promote a dense material in a reduced time when compared to the conventional sintering process. In order to sintering the MoSi2 powder, green compacts of 6mm of diameter and 1.6mm thickness were produced in a steel die in a uniaxial press at 100MPa and after, isostatic pressed at 350MPa. The micrograph of the samples exposed to the laser radiation performed by scanning electron microcopy (SEM) reveal the efficiency of the sintering process and the X-ray diffraction of the powders confirmed the presence of single phase after and before laser processing. The average microhardness of these compacts reached near to 700 Hv0.2 in the cross section to the laser irradiation, indicating the all sintering of the green compact.

Preparation and Microstructure of Pressureless Sintered Si2ON2-SiC Ceramic

2011 ◽  
Vol 335-336 ◽  
pp. 699-703
Author(s):  
Hui Hui Tan ◽  
Zhu Xing Tang ◽  
Xia Zhao ◽  
He Zhang
Keyword(s):  
Bulk Density ◽  
Sintering Temperature ◽  
Pressureless Sintering ◽  
Nitriding Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Effect Of Additives ◽  
Sic Ceramic ◽  
Sintering Method ◽  
Scanning Electron

This paper introduces Si2ON2-SiC ceramic fabricated by pressureless sintering method and studies the effect of additives, nitriding temperatures on bulk density, porosity, phase composition and microstructure. It is discovered that additives MgO, CeO2 can increase the densities of Si2ON2-SiC ceramic apparently, and MgO additive has a better effect than CeO2. Nitriding temperature also is an important factor. The bulk density of the specimen with MgO additive reaches maximum at 1.91 g/cm3 when sintered at 1450 °C, and the bulk density of specimen with CeO2 additive is 1.86 g/cm3 at the same condition while the bulk density of the specimen without additive is only 1.75 g/cSuperscript textm3. The X-ray diffraction and scanning electron microscopy of the specimens show that the amount of Si2ON2 increase with the sintering temperature increase. But when the temperature is higher than 1500 °C the Si2ON2 grains will decompose into Si3N4, and Si2ON2 will vanish at 1550 °C

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