scholarly journals Characterization in the icosahedral phase of the system Al63Cu25Fe12

2021 ◽  
Vol 24 (3) ◽  
pp. 1-5
Author(s):  
Luciano Nascimento ◽  
Anastasia Melnyk

The present work aimed to characterize the microstructure of the icosahedral phase (ɸ-quasicrystalline phase) of the system with stoichiometric composition of the quasicrystal Al63Cu25Fe12. The ternary alloy with nominal composition of Al63Cu25Fe12 was processed by Mechanical Alloying (MA) as a viable solid state processing method for producing various metastable and stable quasicrystalline phases. The structural characterization of the obtained samples was performed by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM), while the elemental composition of the chemical elements Al, Fe and Cu were determined by the technique of X-ray spectroscopy by dispersive energy (EDS). According to the results of XRD, the diffraction patterns of Al63Cu25Fe12 showed the presence of β-Al (Fe, Cu) and λ-Al13Fe4 phases coexist with the thermodynamic ɸ-phase quasicrystalline. Finally, elemental analysis indicates that during alloy synthesis there is little variation of the ideal composition. The results indicate that alloys with high percentage of icosahedral phase can be obtained by casting in the air.

2019 ◽  
Vol 28 (1) ◽  
pp. 51-56
Author(s):  
Anastazia Melnik ◽  
Luciano Nascimento

The present work aimed to characterize the microstructure of the icosahedral phase (quasicrystalline phase-ϕ) of the system with stoichiometric composition of the quasicrystal Al63Cu25Fe12. The ternary alloy with nominal composition of Al63Cu25Fe12 was processed by mechanical alloying (MA) as a viable solid state processing method for producing various metastable and stable quasicrystalline phases. The structural characterization of the obtained samples was performed by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM), while the elemental composition of the chemical elements Al, Fe and Cu were determined by X-ray spectroscopy technique of dispersive energy (EDS). According to the results of XRD, the diffraction patterns of Al63Cu25Fe12 showed the presence of β-Al(Fe, Cu) and λ-Al13Fe4 phases coexist with the thermodynamic ϕ-phase quasicrystalline. Finally, elemental analysis indicates that during alloy synthesis there is little variation of the ideal composition. The results indicate that alloys with high percentage of icosahedral phase can be obtained by casting in the air.


2020 ◽  
Vol 4 (01) ◽  
pp. 1-14
Author(s):  
Luciano Nascimento

The present work aimed to characterize the microstructure of the icosahedral phase (quasicrystalline phase-ϕ) of the system with stoichiometric composition of the quasicrystal Al65Cu25Fe15 . The ternary alloy with nominal composition of Al63Cu25Fe12 was processed by mechanical alloying (MA) as a viable solid state processing method for producing various metastable and stable quasicrystalline phases. The structural characterization of the obtained samples was performed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), while the elemental composition was determined by dispersive energy spectroscopy (DES). The diffraction patterns of Al65Cu25Fe15 showed the presence of ω-Al7Cu2Fe , β-Al(Fe, Cu) and λ-Al13Fe4 phases that coexist with the thermodynamic quasicrystalline phase-ϕ. Finally, elemental analysis indicates that during alloy synthesis there is little variation of the ideal composition. The results indicate that alloys with high percentage of icosahedral phase can be obtained by casting in the air.


2013 ◽  
Vol 27 (04) ◽  
pp. 1350026 ◽  
Author(s):  
JING WANG ◽  
SHENGLIN JIANG ◽  
LINHUA SONG

To meet the requirement of next-generation multilayer ceramic capacitors, the synthesis and characterization of Ba 0.985 Bi 0.01 TiO 3-based high-k dielectric compositions are reported. Solid solutions with a nominal composition of 0.4 Ba 0.985 Bi 0.01 TiO 3–0.6 BaTi 1-x Zr x O 3 (x = 0.001, 0.005, 0.01, 0.02, 0.04, 0.06, 0.1) was synthesized by distillation method. Room-temperature X-ray diffraction patterns showed an increase and then a decrease in the tetragonality of Ba 0.985 Bi 0.01 TiO 3 after modifying with BaTi 1-x Zr x O 3. The decrement in tetragonality (c/a ratio) was accompanied by lowering of Curie temperature. 0.4 Ba 0.985 Bi 0.01 TiO 3–0.6 BaTi 0.995 Zr 0.005 O 3 was found to exhibit diffuse phase transition accompanied by an ultrahigh dielectric constant of 77,619, a loss tangent < 1 and a grain size < 1 μm.


2017 ◽  
Vol 8 ◽  
pp. 1257-1265 ◽  
Author(s):  
Urszula Klekotka ◽  
Magdalena Rogowska ◽  
Dariusz Satuła ◽  
Beata Kalska-Szostko

Ferrite nanoparticles with nominal composition Me0.5Fe2.5O4 (Me = Co, Fe, Ni or Mn) have been successfully prepared by the wet chemical method. The obtained particles have a mean diameter of 11–16 ± 2 nm and were modified to improve their magnetic properties and chemical activity. The surface of the pristine nanoparticles was functionalized afterwards with –COOH and –NH2 groups to obtain a bioactive layer. To achieve our goal, two different modification approaches were realized. In the first one, glutaraldehyde was attached to the nanoparticles as a linker. In the second one, direct bonding of such nanoparticles with a bioparticle was studied. In subsequent steps, the nanoparticles were immobilized with enzymes such as albumin, glucose oxidase, lipase and trypsin as a test bioparticles. The characterization of the nanoparticles was acheived by transmission electron microscopy, X-ray diffraction, energy dispersive X-ray and Mössbauer spectroscopy. The effect of the obtained biocomposites was monitored by Fourier transform infrared spectroscopy. The obtained results show that in some cases the use of glutaraldehyde was crucial (albumin).


2014 ◽  
Vol 793 ◽  
pp. 23-27
Author(s):  
C. Patiño-Carachure ◽  
J. Luis López-Miranda ◽  
F. de la Rosa ◽  
M. Abatal ◽  
R. Pérez ◽  
...  

In this investigation the Al64Cu24Fe12 alloy was melted in an induction furnace and solidified under normal casting conditions. The as-cast sample was subject to a heat treatment at 700 oC under argon atmosphere in order to obtain the icosahedral quasicrystalline phase in a monophase region. Subsequently, the icosahedral phase was milled for different times and water added conditions. The pre-alloyed and milled powders were characterized using scanning electron microscopy, X-Ray diffraction, and transmission electron microscopy. The experimental results showed that the icosahedral phase is sensitive to the reaction between water and aluminum of the quasicrystalline alloy to generate hydrogen. As the milling time and the amount of water are increased, the embrittlement reaction of the alloy is accentuated releasing more hydrogen.


Author(s):  
Fikri Alatas ◽  
Fahmi Abdul Azizsidiq ◽  
Titta Hartyana Sutarna ◽  
Hestyari Ratih ◽  
Sundani Nurono Soewandhi

An effort to improve the solubility of albendazole (ABZ), an anthelmintic drug has been successfully carried out through the formation of multicomponent crystal with dl-malic acid (MAL). Construction of phase solubility curve of ABZ in MAL solution and crystal morphological observations after recrystallization in the acetone-ethanol (9:1) mixture were performed for initial prediction of multicomponent crystal formation. ABZ-MAL multicomponent crystal was prepared by wet grinding or also known as solvent-drop grinding (SDG) with acetone-ethanol (9:1) mixture as a solvent followed by characterization of the multicomponent crystal formation by powder X-ray diffraction and Fourier transform infrared (FTIR) methods. The solubility of ABZ-MAL multicomponent crystal was tested in water at ambient temperature and in pH 1.2, 4.5 and 6.8 of buffered solutions at 37°C. The phase solubility curve of the ABZ in the MAL solution showed type Bs. The ABZ-MAL mixture has a different crystalline morphology than pure ABZ and MAL after recrystallization in the acetone-ethanol mixture (9:1). The powder X-ray diffraction pattern and the FTIR spectrum of ABZ-MAL from SDG different from intact ABZ and MAL powder X-ray diffraction patterns and these results can indicate the ABZ-MAL multicomponent crystal formation. The ABZ-MAL multicomponent crystal has better solubility than pure ABZ in all media used. These results can be concluded that ABZ-MAL multicomponent crystal can be prepared by solvent-drop grinding method with acetone-ethanol (9:1) mixture as a solvent and can increase the solubility of albendazole.


2005 ◽  
Vol 03 (2) ◽  
pp. 24-29
Author(s):  
P.M. PIMENTEL ◽  
A.M.G. PEDROSA ◽  
H.K.S. SOUZA ◽  
C.N.S. JÚNIOR ◽  
R.C.A. PINTO ◽  
...  

Spinel oxides with the composition ZnCo2O4 and ZnCo2O4:Eu3+ have been synthesized by the Pechini method and characterized by X-ray diffraction, infrared spectroscopy, thermal analysis and scanning electron microscopy. IR spectroscopy revealed the presence of n1 and n2 bands, typical of spinel structures. The formation of monophase cubic spinel structure was confirmed by X-ray diffraction patterns. Extra lines corresponding to other phase has been observed in the powders calcined at 900 ºC. The results showed the extremely lower synthesis temperature than those presents in conventional methods.


2004 ◽  
Vol 831 ◽  
Author(s):  
Phanikumar Konkapaka ◽  
Huaqiang Wu ◽  
Yuri Makarov ◽  
Michael G. Spencer

ABSTRACTBulk GaN crystals of dimensions 8.5 mm × 8.5 mm were grown at growth rates greater than 200μm/hr using Gallium Vapor Transport technique. GaN powder and Ammonia were used as the precursors for growing bulk GaN. Nitrogen is used as the carrier gas to transport the Ga vapor that was obtained from the decomposition of GaN powder. During the process, the source GaN powder was kept at 1155°C and the seed at 1180°C. Using this process, it was possible to achieve growth rates of above 200 microns/hr. The GaN layers thus obtained were characterized using X-Ray diffraction [XRD], scanning electron microscopy [SEM], and atomic force microscopy [AFM]. X-ray diffraction patterns showed that the grown GaN layers are single crystals oriented along c direction. AFM studies indicated that the dominant growth mode was dislocation mediated spiral growth. Electrical and Optical characterization were also performed on these samples. Hall mobility measurements indicated a mobility of 550 cm2/V.s and a carrier concentration of 6.67 × 1018/cm3


2021 ◽  
Vol 1039 ◽  
pp. 307-312
Author(s):  
Mohammad Malik Abood ◽  
Osama Abdul Azeez Dakhil ◽  
Aref Saleh Baron

Methyl ammonium lead iodide CH3NH3PbI3 Perovskite was synthesized by a new method mixing between one and two steps, in addition, the ethanol solvent was used to dissolve CH3NH3I and compared with isopropanol solvent. The characterizations of synthesized perovskite samples included the structural properties, morphological characteristics and optical properties. The intensity and orientation in X-ray diffraction patterns appear clearly in ethanol solvent while disappearing at a peak at 12o due to the speed reaction of perovskite in this solvent. Additionally, the ethanol solvent increasing the grain size of perovskite which homogeneity of the surface morphology. the ethanol solvent cause a decrease in the wavelength of absorbance edge in addition to an increase in the energy bandgap value. Keywords: Ethanol Solvent, Perovskite, Photovoltaic Technologies, X-ray diffraction.


1996 ◽  
Vol 11 (3) ◽  
pp. 230-234 ◽  
Author(s):  
M. D. Santos ◽  
J. R. Matos ◽  
L. R. F. Carvalho ◽  
L. M. Sant’Agostino ◽  
M. Korn

Characterization of some crystalline species present in atmospheric particulate matter can be investigated by an X-ray diffractometric technique. According to the analytical strategy, filtering media suitable for collecting airborne particles must be selected. In order to recognize the X-ray diffraction patterns and consequently the inherent analytical interference of filtering media, a systematic X-ray diffraction evaluation of several substrates was performed. Although artifact formation during ambient sampling can occur on quartz and glass fiber filters, these filters were also included in the diffractometric characterization. In this work, commercial filters were thermally treated and submitted to X-ray diffraction scanning. Results have shown pronounced variations in the diffractometric profiles of each thermally treated substrate. The selection criteria for choosing the filtering media was established by considering their chemical and physical properties and also the crystalline species to be collected on them.


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