Artículos de revistas: "Copper crystalline phases"

1

Semenov, A. P., Dmitriy Badma-Dorzhievich Tsyrenov y I. A. Semenova. "Sintez nanokompozitnykh pokrytiy TiN-Cu na printsipe sopryazheniya protsessov vakuumno-dugovogo ispareniya, magnetronnogo raspyleniya i raspyleniya ionnym puchkom". Микология и фитопатология, n.º 2 (15 de diciembre de 2023): 45–47. http://dx.doi.org/10.31857/s0869573323020064.

Texto completo

Resumen

Superhard TiN-Cu composite coatings have been obtained, the synthesis of which is based on the principle of coupling the operating modes of a vacuum arc evaporator a planar magnetron and a plasma ion source. The constitution, structure and properties of TiN-Cu composite coating do not depend on the type of hybrid methods of their synthesis. It is shown that the coatings have a characteristic homogeneous globular structure with crystallite sizes in the range of 20-50 nm and are textured along the plane (111). Copper does not form its own crystalline phase and is not in the crystal lattice of other phases, it is located at the boundaries of crystallites in an amorphous or X-ray amorphous state. The copper content throughout the coating profile is 5-10 at.%. The microhardness of the coatings is 38-42 GPa.

Los estilos APA, Harvard, Vancouver, ISO, etc.

2

Che Halin, Dewi Suriyani, Norainiza Saud y Haiza Haroon. "Microstructure Study on Cuprous Oxide Thin Films Deposited on n-Si Substrate via Sol-Gel Spin Coating Technique". Materials Science Forum 803 (agosto de 2014): 362–66. http://dx.doi.org/10.4028/www.scientific.net/msf.803.362.

Texto completo

Resumen

Cuprous oxide thin films were prepared by sol-gel method was successfully deposited onto n-Si substrate. Sol solutions were prepared by dissolving copper (II) acetate in isopropyl alcohol. Diethanolamine and glucopone were added into the sol solution to dissolve the copper (II) acetate rapidly to prevent the precipitation of blue copper (II) acetate. Crystalline phases are identified by X-ray diffraction (XRD) and the crystallite size is estimated by using Scherrer’s formula which indicates that the largest crystallite size is 41.84 nm with the lowest lattice parameter 4.25 Å. The optical band gap of the films is determined by optical absorption technique and the surface morphologies of films are analyzed by scanning electron microscopy (SEM). The SEM micrographs show that the particles agglomerate with different shapes and sizes.

Los estilos APA, Harvard, Vancouver, ISO, etc.

3

White, Rachel, Paul Thomas, Matthew R. Phillips, Ken Moran y Richard Wuhrer. "X-Ray Mapping and Scatter Diagram Analysis of the Discoloring Products Resulting from the Interaction of Artist's Pigments". Microscopy and Microanalysis 16, n.º 5 (31 de agosto de 2010): 594–98. http://dx.doi.org/10.1017/s143192761009375x.

Texto completo

Resumen

AbstractThe discoloring interaction between the artist's pigments cadmium yellow and the copper-containing malachite, an interaction that is conjectured to cause black spotting in oil paintings of the 19th and early 20th centuries, was examined using X-ray mapping and scatter diagram analysis. The application of these coupled techniques confirmed that copper sulfide phases were produced during discoloration reaction. Scatter diagram analysis indicated that two copper sulfide stoichiometries (CuS and Cu3S2) were present as reaction products where previously only crystalline CuS (covellite) had been identified by X-ray diffraction. The results demonstrate the potential of X-ray mapping coupled with scatter diagram analysis for the identification of both crystalline and X-ray amorphous phases produced by such complex heterogeneous interactions and their applicability to the investigation of interactions of artists' pigments.

Los estilos APA, Harvard, Vancouver, ISO, etc.

4

Wang, Xin. "Surface Crystallization in Mg-Based Bulk Metallic Glass during Copper Mold Casting". Advances in Materials Science and Engineering 2014 (2014): 1–4. http://dx.doi.org/10.1155/2014/798479.

Texto completo

Resumen

The localized crystallization of Mg54Cu28Ag7Y11bulk metallic glass (BMG) in the injection casting process using a copper mold was investigated. It has been found that several crystalline phases were formed close to the as-cast surface but did not exist in the internal part of the BMG plate. It is abnormal that the as-cast surface is partially crystallized with higher cooling rate than that of inside. Overheating of the melt and nucleation induced by the surface of copper mold play key roles in the abnormal crystallization. It is suggested that the function of copper mold to trigger heterogeneous nucleation cannot be totally ignored, although it provides the high cooling rate for the glass formation during casting.

Los estilos APA, Harvard, Vancouver, ISO, etc.

5

Wang, Yi Ming, Li Jing Zheng y Shu Jie Pang. "Formation and Mechanical Properties of Mg-Cu-Al-Gd Bulk Metallic Glass Composites". Materials Science Forum 650 (mayo de 2010): 290–94. http://dx.doi.org/10.4028/www.scientific.net/msf.650.290.

Texto completo

Resumen

The effect of Al addition to Mg65Cu25Gd10 glassy alloy on the microstructure, thermal properties and mechanical properties were investigated. The Mg65Cu25-xAlxGd10 (x=1-7at. %) bulk metallic glass composites were formed by copper mold casting, and the fraction and size of the crystalline phases in the glassy matrix changed with the Al content. The Mg65Cu24Al1Gd10 glass composite consisted of a small amount of crystalline phases in the glassy matrix possesses high compressive strength up to about 850 MPa.

Los estilos APA, Harvard, Vancouver, ISO, etc.

6

Phiri, Tina, Pritam Singh y Aleksandar Nikoloski. "Mineralogical Characterisation of Copper Slag and Phase Transformation after Carbocatalytic Reduction for Hydrometallurgical Extraction of Copper and Cobalt". Metals 14, n.º 10 (1 de octubre de 2024): 1119. http://dx.doi.org/10.3390/met14101119.

Texto completo

Resumen

Copper smelting slag is a significant potential resource for cobalt and copper. The recovery of copper and cobalt from copper slag could significantly augment the supply of these metals, which are essential to facilitating the transition to green energy while simultaneously addressing environmental concerns regarding slag disposal. However, the complex mineral composition of copper slag poses an enormous challenge. This study investigated the mineralogical and chemical characteristics of copper slag, which are vital for devising the most effective processing techniques. XRD and FESEM-EDS were employed to examine the morphologies of copper slag before and after the reduction process. The effects of borax and charcoal (carbocatalytic) reduction on phase transformation were evaluated. The XRD analysis revealed that the primary phases in the copper slag were Fe2SiO4 and Fe3O4. The FESEM-EDS analysis verified the presence of these phases and yielded supplementary details regarding metal embedment in the Fe2SiO4, Fe3O4, and Cu phases. The carbocatalytic reduction process expedited the transformation of copper slag microstructures from crystalline dendritic to amorphous and metallic phases. Finally, leaching experiments demonstrated the potential benefits of carbocatalytic reduction by yielding high extractions of Cu, Co, and Fe.

Los estilos APA, Harvard, Vancouver, ISO, etc.

7

Purvis, O. W., B. Pawlik-Skowrońska, G. Cressey, G. C. Jones, A. Kearsley y J. Spratt. "Mineral phases and element composition of the copper hyperaccumulator lichen Lecanora polytropa". Mineralogical Magazine 72, n.º 2 (abril de 2008): 607–16. http://dx.doi.org/10.1180/minmag.2008.072.2.607.

Texto completo

Resumen

AbstractMineral phases and element localization were investigated in the vivid turquoise-coloured lichen, Lecanora polytropa, sampled from a psammite boulder in a wall supporting mine spoil at the abandoned copper mine, Riddarhyttan Kopparverke, southern Sweden. Normally pale yellowish (usnic acid), the lichen is turquoise coloured internally with bluish inclusions. X-ray mapping shows that Cu occurs on and within the lichen and does not coincide with P or S, suggesting that it is indeed associated with carbon or other elements not detected (or reported) using X-ray mapping. Scanning electron microscopy in back-scatter mode confirmed that the greatest Cu concentrations occur in the form of crystalline aggregates in coloured inclusions below the major internal turquoise layer with smaller Cu contents. X-ray diffraction with a position-sensitive detector (XRD-PSD) confirmed coloured crystalline aggregates consisted of the copper oxalate, moolooite. The study confirms the value of XRD-PSD as a non-destructive tool to characterize small (~50 μm) metal oxalate inclusions obtained from within lichen samples.

Los estilos APA, Harvard, Vancouver, ISO, etc.

8

Ma, Minghong y Yongqian Huang. "Impact of adding Na₂SiF₆ on the crystal phase and copper valence state in glass ceramics made from leftover granite for use as architectural ornamentation". Journal of Physics: Conference Series 2842, n.º 1 (1 de septiembre de 2024): 012017. http://dx.doi.org/10.1088/1742-6596/2842/1/012017.

Texto completo

Resumen

Abstract The accumulation of granite waste can result in the occupation of a considerable amount of land resources. Using granite waste as glass ceramics for architectural decoration represents a potential solution to this issue. The microstructure, valence state, and crystalline phase of copper ions were examined by using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The findings demonstrated that the concentration of Na2SiF6 affects the valence condition of Cu ions in crystallized glass. The crystalline phases of the sample containing 1.84 wt% Na2SiF6 consisted of forsterite (MgSiO3) and diopside (CaMgSi2O6), and the Cu+ accounted for 39.9% of the total Cu ions in the sample which showed a grey-black color. For the sample containing 3.67 wt% Na2SiF6, the crystalline phases consisted of richterite (Na, F) syn (Na (Na, Ca) Mg5Si8O22F2), cuprite (Cu2O), and forsterite, its Cu+ accounted for 39.9%, and the sample appeared orange-red. With the increase of Na2SiF6 content, the percentage of Cu+ in the total Cu ions showed an increasing trend, and the corresponding red color of the samples gradually deepened.

Los estilos APA, Harvard, Vancouver, ISO, etc.

9

Maldivi, P., D. Guillon, A. M. Giroud-Godquin, J. C. Marchon, H. Abied, H. Dexpert y A. Skoukios. "Copper K edge EXAFS spectroscopy of the crystalline and columnar phases of copper (II) carboxylates". Journal de Chimie Physique 86 (1989): 1651–64. http://dx.doi.org/10.1051/jcp/1989861651.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

10

Dyakova, Vanya, Hristina Spasova, Yoanna Kostova, Yana Mourdjeva y Georgi Stefanov. "EFFECT OF CU AS МINORITY АLLOYING ЕLEMENT ON GLASS FORMING ABILITY AND CRYSTALLIZATION BEHAVIOR OF RAPIDLY SOLIDIFIED AL-SI-NI RIBBONS". ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference 3 (13 de junio de 2023): 69–73. http://dx.doi.org/10.17770/etr2023vol3.7200.

Texto completo

Resumen

The influence of copper as a minority alloying element in the process of rapid solidification of Al-Si-Ni ribbons produced by Chill Block Melt Spinning (CBMS) was investigated. XRD and TEM analyses proved a completely amorphous structure of the alloys Al74Ni16Si10 and (Al74Ni16Si10)98Cu2. The crystallization behaviour of these alloys was studied by DSC analysis. It was found that the crystallization of the amorphous alloys (Al74Ni16Si10)100-xCux, x=0, 2 runs in two steps. The temperatures Tx1 and Tx2 of each of the crystallization steps were determined. It was proven that the addition of 2 at. % copper does not significantly change Tx temperatures. The temperature difference ΔTx was calculated and it showed that more thermally stable is the copper containing alloy. Crystalline analogues of the amorphous alloys were obtained by annealing of the melt-spun amorphous ribbons at a temperature which exceeded by 170°C the onset crystallization temperature. The type and size of separated crystalline phases were determined by XRD. It was found that the addition of 2 at. % Cu to Al74Ni16Si10 alloy causes a separation of new phases - Cu3.8Ni and (Al, Cu)Ni3 and 54%, 24% and 7% size increase of the phases Al, Al3Ni, NiSi2 respectively.

Los estilos APA, Harvard, Vancouver, ISO, etc.

11

Amin, Muhammad, Saadat A. Siddiqi, Ahmad Ashfaq, Murtaza Saleem, Shahid M. Ramay, Asif Mahmood y Yousef S. Al-Zaghayer. "Study of structural and magnetic properties of melt spun Nd2Fe13.6Zr0.4B ingot and ribbon". Modern Physics Letters B 29, n.º 35n36 (30 de diciembre de 2015): 1550250. http://dx.doi.org/10.1142/s0217984915502504.

Texto completo

Resumen

Nd2Fe[Formula: see text]Zr[Formula: see text]B hard magnetic material were prepared using arc-melting technique on a water-cooled copper hearth kept under argon gas atmosphere. The prepared samples, Nd2Fe[Formula: see text]Zr[Formula: see text]B ingot and ribbon are characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) for crystal structure determination and morphological studies, respectively. The magnetic properties of the samples have been explored using vibrating sample magnetometer (VSM). The lattice constants slightly increased due to the difference in the ionic radii of Fe and that of Zr. The bulk density decreased due to smaller molar weight and low density of Zr as compared to that of Fe. Ingot sample shows almost single crystalline phase with larger crystallite sizes whereas ribbon sample shows a mixture of amorphous and crystalline phases with smaller crystallite sizes. The crystallinity of the material was highly affected with high thermal treatments. Magnetic measurements show noticeable variation in magnetic behavior with the change in crystallite size. The sample prepared in ingot type shows soft while ribbon shows hard magnetic behavior.

Los estilos APA, Harvard, Vancouver, ISO, etc.

12

Khorokhorina, Irina V., Sergey I. Lazarev, Yuri M. Golovin y Dmitry S. Lazarev. "STRUCTURAL CHARACTERISTICS OF MEMBRANES AND KINETIC DEPENDENCES OF ELECTRONANOFILTRATION WASTE WATER TREATMENT OF LATINATING PROCESS". IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 63, n.º 7 (22 de mayo de 2020): 95–102. http://dx.doi.org/10.6060/ivkkt.20206307.6117.

Texto completo

Resumen

The basic structural characteristics of the membrane and kinetic dependences of the electron-filtration separation of wastewater of the brassing process are investigated. The retention factor and the specific output flow for the near-anode and near-cathode membrane were calculated. The dependences of the retention factor and the specific output flow on the transmembrane pressure and current density are analyzed, and it is noted that the anode membrane as a result of the application of a constant electric potential to the membrane-solution system starts to clog and a sludge layer forms on its surface due to the electrochemical process. A comparison is made of the retention capacity of OPMN-P and OPMN-K membranes for a real spent technological solution after the process of brazing and a model solution containing the same concentrations of copper ions (Cu2+) and zinc (Zn2+) as in real runoff. The structural characteristics of nanofiltration membranes of the type OFAM-K and OPMN-P were studied and analyzed. Changes in the crystalline and amorphous phases of the active layer and the membrane substrate are considered. The change in crystalline parameters in crystallites can be explained only by the structural features of macromolecules of polyamide and their orientation during crystallization. Under the action of transmembrane pressure and transport of water molecules, the polymorphism of the packing of the crystal lattice occurs. The packing density of the amorphous phases of the working membrane decreases, which affects the transport and selective properties of the membrane. In fact, the deformation of an amorphous-crystalline polymer leads to a restructuring of the structure not only in the orientation of the macromolecules of the amorphous, but also the crystalline phases of the membranes. It was also noted that the packing density of the amorphous phases of the working membrane decreases, which affects the transport and selective properties of the membrane.

Los estilos APA, Harvard, Vancouver, ISO, etc.

13

Prasad, Arun S. "Green synthesis and spectral analysis of surface encapsulated copper (II) oxide nanostructures". Materials Science-Poland 37, n.º 3 (1 de septiembre de 2019): 503–9. http://dx.doi.org/10.2478/msp-2019-0062.

Texto completo

Resumen

AbstractNanostructures of copper (II) oxide were synthesized through chemical reduction of copper (II) sulfate pentahydrate using phytochemicals present in leaf extracts of Leucas aspera. The crystalline phases and size were assessed by X-ray diffraction data analysis. From the Bragg reflection peaks, existence of monoclinic end-centered phase of copper (II) oxide along with presence of cubic primitive phase of copper (I) oxide and traces of cubic face centered lattices of zero valent copper was revealed. The three Raman active modes corresponding to CuO phase were identified in the sample with permissible merging of characteristic bands due to nanostructuring and organic capping. The surface topography measurement using field emission scanning electron microscope evidenced the occurrence of cylindrical rod shaped morphological structures along with a number of unshaped aggregates in the sample. The effective crystallite size and lattice strain were estimated from Williamson-Hall analysis of Bragg reflection data. Tauc plot analysis of UV-Vis-NIR absorption data in direct transition mode provided an estimation of band gap, viz. 1.83 eV and 2.06 eV respectively, for copper (II) oxide and copper (I) oxide. Thermal degradation study using thermogravimetric curve analysis could reveal the amount of moisture content, volatile components as well as the polymer capping over nanorods present in the sample. It could be seen that upon heating, inorganic core crystals undergo oxidation process and at temperature above 464 °C, the sample was found to be composed solely of inorganic crystallite phase of copper (II) oxide.

Los estilos APA, Harvard, Vancouver, ISO, etc.

14

Fausto, Rui, M. F. Ramos Moita y Maria Leonor T. S. Duarte. "An FT-IR spectroscopic study of the crystalline and columnar liquid-crystalline phases of copper (II) carboxylates". Journal of Molecular Structure 349 (abril de 1995): 439–42. http://dx.doi.org/10.1016/0022-2860(95)08803-4.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

15

Betancourt-Galindo, R., P. Y. Reyes-Rodriguez, B. A. Puente-Urbina, C. A. Avila-Orta, O. S. Rodríguez-Fernández, G. Cadenas-Pliego, R. H. Lira-Saldivar y L. A. García-Cerda. "Synthesis of Copper Nanoparticles by Thermal Decomposition and Their Antimicrobial Properties". Journal of Nanomaterials 2014 (2014): 1–5. http://dx.doi.org/10.1155/2014/980545.

Texto completo

Resumen

Copper nanoparticles were synthesized by thermal decomposition using copper chloride, sodium oleate, and phenyl ether as solvent agents. The formation of nanoparticles was evidenced by the X-ray diffraction and transmission electron microscopy. The peaks in the XRD pattern correspond to the standard values of the face centered cubic (fcc) structure of metallic copper and no peaks of other impurity crystalline phases were detected. TEM analysis showed spherical nanoparticles with sizes in the range of 4 to 18 nm. The antibacterial properties of copper nanoparticles were evaluatedin vitroagainst strains ofStaphylococcus aureusandPseudomonas aeruginosa. The antibacterial activity of copper nanoparticles synthesized by thermal decomposition showed significant inhibitory effect against these highly multidrug-resistant bacterial strains.

Los estilos APA, Harvard, Vancouver, ISO, etc.

16

Tomšič, Sara, Janez Košmrlj y Andrej Pevec. "Four Different Crystalline Products from One Reaction: Unexpected Diversity of Products of the CuCl2 Reaction with N-(2-Pyridyl)thiourea". Acta Chimica Slovenica 67, n.º 4 (15 de diciembre de 2020): 1290–300. http://dx.doi.org/10.17344/acsi.2020.6252.

Texto completo

Resumen

The reaction of N-(2-pyridyl)thiourea with CuCl2 in methanol yields four different crystalline products: yellow dimeric complex, [Cu2Cl2(μ-Cl)2(L)2] (1), red polymeric complex, [Cu3Cl8L2]n (2), orange crystalline product with ionic structure, L2[CuCl4] (3), and colourless ionic compound LCl (4), where L = 2-amino-[1,2,4]thiadiazolo[2,3-a]pyridin-4-ium cation as a result of oxidative cyclization of N-(2-pyridyl)thiourea. The crystal structures of all these crystalline products have been determined by single-crystal X-ray diffraction analysis. Compound 1 involves a copper(I) ion while in 2 and 3 the copper centre is in the divalent state. 1H NMR spectra for compounds 1–3 are identical and confirm deprotonated thioamide groups of N-(2-pyridyl)thiourea and the formation of a thiadiazolopyridinium cation in solution. The hydrogen bonding and π–π stacking interactions were investigated in the solid state. In addition, all crystalline products 1–4 exhibit also S···Cl bonding interactions which consolidate the complexes into networks. The X-ray diffraction analyses indicate the absence of other crystalline phases in the crude reaction mixture.

Los estilos APA, Harvard, Vancouver, ISO, etc.

17

Mos, Yvonne M., Arnold C. Vermeulen, Cees N. J. Buisman y Jan Weijma. "X-Ray Diffraction of Iron Containing Samples: The Importance of a Suitable Configuration". Solid State Phenomena 262 (agosto de 2017): 545–48. http://dx.doi.org/10.4028/www.scientific.net/ssp.262.545.

Texto completo

Resumen

X-ray diffraction (XRD) is a commonly used technology to identify crystalline phases. However, care must be taken with the combination of XRD configuration and sample. Copper (most commonly used radiation source) is a poor match with iron containing materials due to induced fluorescence. Magnetite and maghemite are analysed in different configurations using copper or cobalt radiation. Results show the effects of fluorescence repressing measures and the superiority of diffractograms obtained with cobalt radiation. Diffractograms obtained with copper radiation make incontestable phase identification often impossible. Cobalt radiation on the other hand yields high quality diffractograms, making phase identification straightforward.

Los estilos APA, Harvard, Vancouver, ISO, etc.

18

Tam, C. Y. y C. H. Shek. "Oxidation-induced copper segregation in Cu60Zr30Ti10 bulk metallic glass". Journal of Materials Research 21, n.º 4 (1 de abril de 2006): 851–55. http://dx.doi.org/10.1557/jmr.2006.0120.

Texto completo

Resumen

Copper segregation in a subsurface layer during annealing of Cu60Zr30Ti10 bulk metallic glass at 773 K under oxygen atmosphere has been investigated by x-ray diffraction, Auger electron spectroscopy, x-ray photoelectron spectroscopy, and scanning electron microscopy. The formation of metallic copper is strongly dependent on the annealing environment. Various oxides with metallic copper are formed after annealing in oxygen atmosphere, but only crystalline intermetallic phases are found under vacuum annealing. Besides, surface characterization results show that the sample annealed in oxygen and vacuum result in enrichment and depletion of Cu on the surface region, respectively.

Los estilos APA, Harvard, Vancouver, ISO, etc.

19

Caccavale, F., C. Sada, F. Segato, L. D. Bogomolova, N. A. Krasil'nikova, Yu N. Korkishko, V. A. Fedorov y T. V. Morozova. "Copper–lithium ion exchange in LiNbO3". Journal of Materials Research 15, n.º 5 (mayo de 2000): 1120–24. http://dx.doi.org/10.1557/jmr.2000.0159.

Texto completo

Resumen

Copper-doped LiNbO3 waveguides were prepared by Cu–Li ion-exchange process. Compositional, structural, and optical analyses were performed by secondary ion mass spectrometry, x-ray diffraction, and m-line spectroscopy, respectively. The chemical state of Cu2+ ions was studied by electron paramagnetic resonance, and the results were correlated with structural modification of the LiNbO3 matrix. Copper incorporation in the crystal took place under different regimes, and it induced a lattice rearrangement with the formation of new crystalline phases. Cu2+ ions were surrounded by tetragonally compressed octahedra with rhombic distortions. Cu:LiNbO3 optical waveguides were formed supporting two optical modes.

Los estilos APA, Harvard, Vancouver, ISO, etc.

20

Nitsenko, A. V., V. N. Volodin, X. A. Linnik, F. Kh Tuleutay y N. M. Burabaeva. "Distillation recovery of tellurium from copper telluride in oxide forms". Izvestiya Vuzov. Tsvetnaya Metallurgiya (Universities' Proceedings Non-Ferrous Metallurgy) 28, n.º 4 (18 de agosto de 2022): 45–54. http://dx.doi.org/10.17073/0021-3438-2022-4-45-54.

Texto completo

Resumen

The paper presents the results of studies into tellurium extraction from its compounds with copper in the form of oxides by the pyrometallurgical method. Commercial copper telluride of Kazakhmys Corporation LLP containing crystalline phases, wt.%: Cu7Te4 – 36.5; Cu5Te3 – 28.5; Cu2Te – 12.9; Cu2.5SO4(OH)3·2H2O – 16.2 and Cu3(SO4)(OH)4 – 6.0 was used as an object of research. The physical and chemical research and technology experiments showed the fundamental possibility of commercial copper telluride processing by oxidative distillation roasting with the extraction of tellurium into a separate product. Air oxygen was used as an oxidant. It was established that a pressure decrease in the range of 80–0.67 kPa at the same temperature entails an increase in the degree of tellurium extraction. However, the tellurium extraction degree (93.0–98.0 %) at all pressures (within 1 hour) acceptable from the technology point of view is achieved at 1100 °C. Increasing the exposure to 3 hours has a minor beneficial effect. Diffractometric studies of cinders from technology experiments showed a decrease in the content of copper oxides in the pressure range of 80–40 kPa and an increase in the Cu3TeO6 phase content. With a subsequent increase in rarefaction from 40 to 0.67 kPa, there is a noticeable decrease in the amount of cuprite and, as a consequence, a sharp increase in the amount of cuprous oxide. A slowdown in the increase of the copper tellurate volume was noted at pressures of 40–20 kPa, and a sharp drop in its content at pressures below 13.3 kPa. The derived condensate is a free-flowing mixture of crystalline phases of tellurium dioxide (67.7 %) and tellurium oxysulfate (32.3 %). This condensate is a middling product for further production of elemental tellurium.

Los estilos APA, Harvard, Vancouver, ISO, etc.

21

Koga, Guilherme, Lucas Otani, Ana Silva, Virginie Roche, Ricardo Nogueira, Alberto Jorge, Claudemiro Bolfarini, Claudio Kiminami y Walter Botta. "Characterization and Corrosion Resistance of Boron-Containing-Austenitic Stainless Steels Produced by Rapid Solidification Techniques". Materials 11, n.º 11 (5 de noviembre de 2018): 2189. http://dx.doi.org/10.3390/ma11112189.

Texto completo

Resumen

The composition of a commercial duplex stainless steel was modified with boron additions (3.5, 4.5, and 5.5 wt.%) and processed by rapid-quenching techniques: Melt-spinning, copper-mold casting, and high-velocity oxygen fuel (HVOF). Spray deposition was also used to produce alloys as the process may induce rapid-solidified-like microstructures. These processing routes led to microstructures with distinguished corrosion resistance. Among the alloys with different boron contents, the 63.5Fe25Cr7Ni4.5B composition enabled the production of fully amorphous ribbons by melt-spinning. The cooling rate experienced during copper-mold casting, high-velocity oxygen fuel, and spray deposition did not ensure complete amorphization. The crystalline phases thereby formed were (Fe,Cr)2B and (Fe,Mo)3B2 borides in an austenitic-matrix with morphology and refinement dependent of the cooling rates. Fully amorphous 63.5Fe25Cr7Ni4.5B ribbons exhibited outstanding corrosion resistance in chloride-rich alkaline and acid media with negligible corrosion current densities of about 10−8 A/cm² and a broad passivation plateau. Although the specimens of the same composition produced by HVOF process and spray deposition exhibited lower corrosion resistance because of intrinsic porosity and crystalline phases, their corrosion behaviors were superior to those of AISI 1045 steel used as substrate with the advantage to be reinforced with hard borides known to be resistant against wear.

Los estilos APA, Harvard, Vancouver, ISO, etc.

22

Abd-Elnaiem, Alaa M., Moustafa A. Abdel-Rahim, Atta Y. Abdel-Latief, Ahmed Abdel-Rahim Mohamed, Kristina Mojsilović y Wojciech Jerzy Stępniowski. "Fabrication, Characterization and Photocatalytic Activity of Copper Oxide Nanowires Formed by Anodization of Copper Foams". Materials 14, n.º 17 (2 de septiembre de 2021): 5030. http://dx.doi.org/10.3390/ma14175030.

Texto completo

Resumen

In recent paper anodization of copper foams in 0.1 M K2CO3 is reported. Anodization was performed in the voltage range of 5–25 V and in all the cases oxides with a developed surface area were obtained. However, anodizing only at 20 and 25 V resulted in the formation of nanostruc-tures. In all the cases, the products of anodizing consisted of crystalline phases like cuprite (Cu2O), tenorite (CuO), parameconite (Cu4O3) as well as spertiniite (Cu(OH)2). Copper foams after ano-dizing were applied as catalysts in the photocatalytic decolorization of a model organic compound such as methylene blue. The highest photocatalytic activity was observed for samples anodized at 25 V and closely followed by samples anodized at 5 V. The anodized copper foams proved to be a useful material in enhancing the photocatalytic efficiency of organic dye decomposition.

Los estilos APA, Harvard, Vancouver, ISO, etc.

23

Kozlov, A. S., P. S. Chizhov, V. A. Filichkina y M. N. Filippov. "Determination of the mineral composition of copper ores by X-Ray methods". Industrial laboratory. Diagnostics of materials 87, n.º 10 (18 de octubre de 2021): 5–11. http://dx.doi.org/10.26896/1028-6861-2021-87-10-5-11.

Texto completo

Resumen

One of the most difficult tasks of the analytical control of copper ores is the determination of the mineral forms of copper. Currently, for this purpose, iodometric and atomic absorption methods are used with preliminary leaching of various mineral forms. The disadvantage of those methods is a rather complicated sample preparation procedure and significant time of analysis. The most universal method for determining the mineral composition of solid samples is the X-ray diffraction method. However, significant variations in the phase composition of copper ores, overlapping reflections of different phases, the presence of an amorphous phase and structural defects necessitate the development of special approaches. In this work, the presence of an amorphous phase is taken into account by direct calculation of the mass fractions of crystalline phases by the G-factor method. The total copper content is determined by the X-ray fluorescence method. Methodological approaches based on using only X-ray methods are proposed, which exclude the procedures of leaching and dissolution of samples and provide determination of primary and secondary copper sulfides using calibration characteristics (3 min), and gaining data on the complete phase composition at the stage of routine analysis (10 – 15 min) and for research purposes (15 – 20 min).

Los estilos APA, Harvard, Vancouver, ISO, etc.

24

Cîrcu, Viorel, Constantin P. Ganea, Mihail Secu, Doina Manaila-Maximean, George Cătălin Marinescu, Roua Gabriela Popescu y Iuliana Pasuk. "Columnar Liquid Crystals of Copper(I) Complexes with Ionic Conductivity and Solid State Emission". Molecules 28, n.º 10 (19 de mayo de 2023): 4196. http://dx.doi.org/10.3390/molecules28104196.

Texto completo

Resumen

Two neutral copper(I) halide complexes ([Cu(BTU)2X], X = Cl, Br) were prepared by the reduction of the corresponding copper(II) halides (chloride or bromide) with a benzoylthiourea (BTU, N-(3,4-diheptyloxybenzoyl)-N′-(4-heptadecafluorooctylphenyl)thiourea) ligand in ethanol. The two copper(I) complexes show a very interesting combination of 2D supramolecular structures, liquid crystalline, emission, and 1D ionic conduction properties. Their chemical structure was ascribed based on ESI–MS, elemental analysis, IR, and NMR spectroscopies (1H and 13C), while the mesomorphic behavior was analyzed through a combination of differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and powder X-ray diffraction (XRD). These new copper(I) complexes have mesomorphic properties and exhibit a hexagonal columnar mesophase over a large temperature range, more than 100 K, as evidenced by DSC studies and POM observations. The thermogravimetric analysis (TG) indicated a very good thermal stability of these samples up to the isotropization temperatures and over the whole temperature range of the liquid crystalline phase existence. Both complexes displayed a solid-state emission with quantum yields up to 8% at ambient temperature. The electrical properties of the new metallomesogens were investigated by variable temperature dielectric spectroscopy over the entire temperature range of the liquid crystalline phase. It was found that the liquid crystal phases favoured anhydrous proton conduction provided by the hydrogen-bonding networks formed by the NH…X moieties (X = halide or oxygen) of the benzoylthiourea ligand in the copper(I) complexes. A proton conductivity of 2.97 × 10−7 S·cm−1 was achieved at 430 K for the chloro-complex and 1.37 × 10−6 S·cm−1 at 440K for the related bromo-complex.

Los estilos APA, Harvard, Vancouver, ISO, etc.

25

Machado, K. D., J. C. de Lima, T. A. Grandi, C. E. M. Campos, C. E. Maurmann, A. A. M. Gasperini, S. M. Souza y A. F. Pimenta. "Structural study of Cu2−x Se alloys produced by mechanical alloying". Acta Crystallographica Section B Structural Science 60, n.º 3 (17 de mayo de 2004): 282–86. http://dx.doi.org/10.1107/s0108768104007475.

Texto completo

Resumen

The crystalline structures of the superionic high-temperature copper selenides Cu2−x Se (0 < x < 0.25) produced using mechanical alloying were investigated using X-ray diffraction (XRD). The measured XRD patterns showed the presence of peaks corresponding to the crystalline superionic high-temperature α-Cu2Se phase in the as-milled sample, and its structural data were determined by means of a Rietveld refinement procedure. After heat treatment in argon at 473 K for 90 h, this phase transforms to the superionic high-temperature α-Cu1.8Se phase, whose structural data were also determined by Rietveld refinement. In this phase, a very low occupation of the trigonal 32(f) sites (∼ 3%) by Cu ions is found. In order to explain the evolution of the phases in the samples, two possible mechanisms are suggested: (i) the high mobility of Cu ions in superionic phases and (ii) the important diffusive processes in the interfacial component of samples produced by mechanical alloying.

Los estilos APA, Harvard, Vancouver, ISO, etc.

26

Berezhnoi, Yu M., D. I. Monastyrsky y O. N. Romanova. "Influence of Polyelectrolytes on the Processes of Structure Formation of Copper Powders". Solid State Phenomena 299 (enero de 2020): 1069–74. http://dx.doi.org/10.4028/www.scientific.net/ssp.299.1069.

Texto completo

Resumen

The results of the studies on the synthesis of ultrafine copper powders are described in the article. The mechanisms of formation of ultrafine powders, using water-soluble polyacrylamide and polyvinyl-pyrrolidone polymers, as particle growth inhibitors, are presented. The processes occurring in the presence of water-soluble polymers and their influence on the structure of the obtained ultrafine copper powders are described. The interaction of the matrix of polymer composite materials with filler particles is analyzed. The kinetics of crystallization and transformation of crystalline phases of the powder, due to the process in the presence of water-soluble polymers, as stabilizers of particle growth, are investigated.

Los estilos APA, Harvard, Vancouver, ISO, etc.

27

Shibutani, Yoji, Jun Young Park y Masato Wakeda. "Shear Banding Analyses of Amorphous Alloys with Crystalline Particles". Materials Science Forum 561-565 (octubre de 2007): 1323–28. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.1323.

Texto completo

Resumen

Plastic deformability of the binary (copper and zirconium) amorphous alloy with embedded nanosized crystals under uniaxial tension and compression is analyzed using molecular dynamics simulations. The number and the size of the nanocrystals are taken as the study parameters. The number of nanocrystals affects the distribution of defects, that is, shear bands nucleation and thus changes the stress-strain curve, whereas the size of the nanocrystals does not significantly influence the response. As already reported in the experimental works, coalescent voids are found under tension in the shear bands or at the interface between crystalline and amorphous phases. This suggests that much attention should be paid to the interface strength around the particles.

Los estilos APA, Harvard, Vancouver, ISO, etc.

28

Khairetdinova, D. R., I. M. Doludenko, I. V. Perunov, I. S. Volchkov, L. V. Panina, D. L. Zagorskiy, K. V. Frolov y V. M. Kanevskii. "Nanowires made of ternary alloys – synthesis features and magnetic properties". Kristallografiâ 69, n.º 5 (23 de octubre de 2024): 866–75. http://dx.doi.org/10.31857/s0023476124050132.

Texto completo

Resumen

Nanowires of FexCoyCu(100–x–y) and FexNiyCu(100–x–y) alloys have been studied. The features of obtaining such structures by the matrix synthesis method have been investigated. Elemental analysis of nanowires grown at sequentially increasing voltages revealed a significant decrease in the amount of copper, as well as a change in the ratio of the main magnetic elements. X-ray phase analysis showed that FeCoCu is a three-component solid solution, while FeNiCu contains three phases of solid solutions: FeCu with copper content up to 80%, FeNi with high iron content, and NiCu in an amorphous or fine-crystalline state with nickel content up to 80%. Mössbauer spectroscopy revealed that the addition of copper can lead to a change in the angle of magnetic moment misalignment in nanowires, which correlates with magnetometry data.

Los estilos APA, Harvard, Vancouver, ISO, etc.

29

Putatunda, Susil K., Khurpa S. Vijayaragavan y Gavin Lawes. "Deposition of Superconducting Thin Films of Magnesium Di-Boride on Various Substrates by Electroless Plating Process". Materials Science Forum 654-656 (junio de 2010): 1840–43. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.1840.

Texto completo

Resumen

Superconducting thin films of magnesium diboride (MgB2) has been synthesized on various substrates such as gold, silver, copper and silicon using a novel electroless plating technique. The microstructures and the superconducting properties of these films have been characterized using X-ray diffraction, scanning electron microscopy and temperature dependent magnetometry. X-ray diffraction measurements confirm that the films are crystalline magnesium diboride with some impurity phases. Clear evidence for a superconducting transition in the magnetization measurements was observed.

Los estilos APA, Harvard, Vancouver, ISO, etc.

30

Biletska, Olga, Kevin J. Laws, Mark Gibson y Michael Ferry. "Production of Mg-Based Bulk Metallic Glass Composites with High Magnesium Content". Materials Science Forum 773-774 (noviembre de 2013): 263–67. http://dx.doi.org/10.4028/www.scientific.net/msf.773-774.263.

Texto completo

Resumen

In this work, in-situ BMG composites based on the Mg-Ni-Gd system with high Mg content (>80 at. %) were produced by copper mould gravity and injection casting methods. The morphology, distribution and volume fraction of the crystalline phases that form in the amorphous matrix was shown to be influenced by cooling rate, composition and casting parameters. Hence, the mechanical properties and deformation behaviour of Mg-Ni-RE BMG composites can be tailored by controlling the microstructure generated during casting.

Los estilos APA, Harvard, Vancouver, ISO, etc.

31

KAYANI, ZOHRA NAZIR, SAIRA RIAZ y SHAHZAD NASEEM. "STRUCTURAL AND MAGNETIC PROPERTIES OF THIN FILM OF IRON NITRIDE". Surface Review and Letters 21, n.º 01 (febrero de 2014): 1450013. http://dx.doi.org/10.1142/s0218625x14500139.

Texto completo

Resumen

The nano-crystalline iron nitride films with a mixture of γ- Fe 4 N , ε Fe 3 N and α Fe 2 N phases were synthesized on copper substrate by sol–gel technology. The structure, morphology and magnetic properties of the samples were characterized using X-ray diffraction, scanning electron microscopy, and vibrating sample magnetometer. The films are ferromagnetic at room temperature. Magnetic properties such as coercive forces and saturation magnetization were found to be 398 Oestered and 32.92 emu/cm3, respectively.

Los estilos APA, Harvard, Vancouver, ISO, etc.

32

Nazari, Roshanak Rafiei, Hoda Enayati Taloobaghi y Hosein Eshghi. "Crystalline phase evolution in nanostructured copper sulfide thin films prepared by spray pyrolysis method: the effect of annealing". Materials Science-Poland 35, n.º 3 (20 de octubre de 2017): 673–80. http://dx.doi.org/10.1515/msp-2017-0083.

Texto completo

Resumen

AbstractIn this study, physical properties of copper sulfide thin films deposited on glass substrates by spray pyrolysis method at different temperatures (260 °C, 285 °C and 310 °C) were investigated. The influence of annealing time on the physical properties of grown layers was also studied. According to FESEM images, the sizes of the compact copper sulfide grains were varied from about 100 nm to 60 nm. Hall effect and resistivity measurements confirmed that all samples had p-type conductivity. The XRD patterns showed that, together with the dominant digenite phase (Cu1.8S) in all samples, the copper-rich phases also appeared as a result of increasing substrate temperature. The optical UV-Vis spectra analysis showed that due to increasing the substrate temperature, the band gap of the layers was reduced from about 2.4 eV to 2.0 eV. We found that as a result of annealing at 400 °C for 1.5 h in Ar atmosphere, the sample which was initially grown at 310 °C with the highest copper content, totally transformed into the polycrystalline monoclinic chalcocite phase (Cu2S) with 3D nanoporous architecture.

Los estilos APA, Harvard, Vancouver, ISO, etc.

33

Shabatina, Tatyana I. y Yurii N. Morosov. "Hybrid Nanosystems Based on Metal-Containing Mesogenic CyanoAlkyl and Alkoxybiphenyls". Crystals 10, n.º 2 (30 de enero de 2020): 77. http://dx.doi.org/10.3390/cryst10020077.

Texto completo

Resumen

The paper reviews the results of the authors on the production of hybrid nanosystems based on liquid crystalline (LC) long-chain cyano(alkyl and alkoxy)biphenyls (5CB, 5OCB, and 8CCB) including nanosized metal species. The samples were obtained through the direct incorporation of metal (silver and copper) atoms and small clusters into mesogenic CB matrices via a low temperature co-condensation technique, and the formation of biligand metal complexes were revealed by FTIR and ESR-spectroscopy. The heating of the systems led to the controlled growth of metal clusters and nanosized metal particles of the definite size beginning from 1 up to 200 nanometers, and their highly-ordered assemblies stabilized in the solid and liquid crystalline phases. It is shown that supramolecular ordering in different LC phases of cyanobiphenyl matrices determines the size and shape of nanosized metal species that are formed in the systems under investigation, as well as the morphology of their aggregates. TEM and atomic force microscopy (AFM) data revealed the existence of orientationally-ordered nanostructures in the nematic phases of 5CB and 5OCB. The growth of quasi-fractal 2D-aggregates was shown for layer-structured smectic mesophase of 8CB. The UV–Visible spectra of hybrid metal–mesogenic nanosystems Ag-5CB and Cu-5CB that were incorporated into polymeric films revealed intensive plasmonic bands at 400–450 nm, similar to silver nanoparticles, and 540–650 nm, similar to copper nanoparticles. The increasing of the metal contents in the samples caused the growth of highly anisometric shaped metal rods, with the ratio of the length to the diameter being more than 10 and plasmonic bands at region of λ ≥ 650 nm.

Los estilos APA, Harvard, Vancouver, ISO, etc.

34

Karpov, I. V. y A. V. Ushakov. "Synthesis of Metal-Organic Framework Structures Based on Copper in a Low-Pressure Arc Discharge Plasma". International Journal of Nanoscience 19, n.º 05 (octubre de 2020): 2050003. http://dx.doi.org/10.1142/s0219581x20500039.

Texto completo

Resumen

Plasma-chemical synthesis of nanopowders based on copper oxide and metal-organic framework structures was carried out using low-pressure arc discharge plasma. The study of the obtained material was carried out by several methods (XRD, FTIR, TEM, TGA and EIS). TEM showed that the obtained powder is highly agglomerated particles with an average particle size of 13 nm, and the crystalline ordering of nanoparticles with a large (about 2 nm) lattice parameter is clearly visible. XRD showed the presence of four crystalline phases corresponding to [Cu3 (BTC)2], Cu, Cu2O and CuO. XRD results are in good agreement with FTIR studies. The DTA curve demonstrates a continuous exothermic process associated with a number of features of plasma-chemical synthesis and the morphology of the obtained nanoparticles. The study of the electrochemical properties of the materials obtained by the method of impedance spectroscopy revealed an anomalous accumulation of electrical charges around the electrodes due to electrochemical reactions for [Cu3 (BTC)2], which are associated with various reactions involving copper species in the organic framework.

Los estilos APA, Harvard, Vancouver, ISO, etc.

35

de Salvi, Simone T. B., Diego Luiz Tita, Carlos de O. Paiva-Santos y Selma G. Antonio. "Characterization of hydrochlorothiazide in solid formulations". Powder Diffraction 30, S1 (4 de mayo de 2015): S127—S130. http://dx.doi.org/10.1017/s0885715615000226.

Texto completo

Resumen

Hydrochlorothiazide (HCTZ) is a diuretic used for the treatment of blood pressure (hypertension). HCTZ has two anhydrous polymorphs denoted as Forms I and II. Aiming at solid-state characterization, X-ray powder diffraction (XRPD) is known to be a powerful technique which has been successfully applied in investigating polymorphism in medicines. In this work, three tablets of HCTZ (a reference and two generic) were analyzed. The data were collected using Rigaku RINT2000 diffractometer copper rotate anode. The Rietveld method (RM) was applied for the characterization of HCTZ polymorphic form. For the crystalline excipients where the crystal structure is known, their phases were identified by the RM either. The results showed that all the tablets exhibit Form I of HCTZ, while the excipient lactose monohydrate is found to exhibit the crystalline form. One of the generics is also found to exhibit the excipient sodium lauryl sulfate (SLS) in the crystalline form. Therefore, the RM and XRPD are an efficient methodology for characterization of the crystalline Form I of the active principle of HCTZ and crystalline excipients lactose monohydrate and SLS in solid formulations. It is also interesting to observe excipients not described in the package insert of the medicament.

Los estilos APA, Harvard, Vancouver, ISO, etc.

36

Caccavale, F., C. Sada, F. Segato, L. D. Bogomolova, V. A. Jachkin y N. A. Krasil'nikova. "Electronic paramagnetic resonance study of Cu2+ ions in copper ion-exchanged layers of lithium niobate crystals". Journal of Materials Research 16, n.º 6 (junio de 2001): 1554–58. http://dx.doi.org/10.1557/jmr.2001.0216.

Texto completo

Resumen

Copper-doped LiNbO3 layers prepared by an Cu–Li ion-exchange process are characterized by electronic paramagnetic resonance. It is found that the majority of Cu2+ ions are coupled by strong exchange interactions which is characteristic of short distances between paramagnetic ions. Such ions are accumulated in a thin layer near the crystal surface and can enter in new crystalline phases formed as a result of the Cu–Li ion exchange. A small amount of Cu2+ ions is incorporated into weakly distorted LiNbO3 crystal lattice inside the diffusion layer.

Los estilos APA, Harvard, Vancouver, ISO, etc.

37

Ivanauskas, Remigijus, Ingrida Ancutienė, Daiva Milašienė, Algimantas Ivanauskas y Asta Bronušienė. "Effect of Reducing Agent on Characteristics and Antibacterial Activity of Copper-Containing Particles in Textile Materials". Materials 15, n.º 21 (30 de octubre de 2022): 7623. http://dx.doi.org/10.3390/ma15217623.

Texto completo

Resumen

Textile materials modified with copper-containing particles have antibacterial and antiviral properties that have prospects for use in healthcare. In the study, textile materials were saturated with copper-containing particles in their entire material volume by the absorption/diffusion method. The antibacterial properties of modified textile materials were confirmed by their inhibitory effect on Staphylococcus aureus, a Gram-positive bacterium that spreads predominantly through the respiratory tract. For the modification, ordinary textile materials of various origins and fiber structures were used. Technological conditions and compositions of modifying solutions were established, as well as the most suitable textile materials for modification. To assess the morphological and physical characteristics of copper-containing particles and the textile materials themselves, X-ray diffraction, a scanning electron microscope, and an energy-dispersive X-ray spectrum were used. In modified textile samples, XRD data showed the presence of crystalline phases of copper (Cu) and copper (I) oxide (Cu2O). On the grounds of the SEM/EDS analysis, the saturation of textile materials with copper-containing particles depends on the structure of the textile materials and the origins of the fibers included in their composition, as well as the modification conditions and the copper precursor.

Los estilos APA, Harvard, Vancouver, ISO, etc.

38

Abied, H., D. Guillon, A. Skoulios, P. Weber, A. M. Giroud-godquin y J. C. Marchon. "Investigation of the Structures of the Crystalline and Columnar Phases of Linear Chain Copper(II) Alkanoates". Liquid Crystals 2, n.º 3 (mayo de 1987): 269–79. http://dx.doi.org/10.1080/02678298708086676.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

39

Napruszewska, Bogna D., Alicja Michalik, Anna Walczyk, Dorota Duraczyńska, Roman Dula, Wojciech Rojek, Lidia Lityńska-Dobrzyńska, Krzysztof Bahranowski y Ewa M. Serwicka. "Composites of Laponite and Cu–Mn Hopcalite-Related Mixed Oxides Prepared from Inverse Microemulsions as Catalysts for Total Oxidation of Toluene". Materials 11, n.º 8 (6 de agosto de 2018): 1365. http://dx.doi.org/10.3390/ma11081365.

Texto completo

Resumen

Composites of Laponite and Cu–Mn hopcalite-related mixed oxides, prepared from hydrotalcite-like (Htlc) precursors obtained in inverse microemulsions, were synthesized and characterized with XRF, XRD, SEM, TEM, H2 temperature-programmed reduction (TPR), and N2 adsorption/desorption at −196 °C. The Htlc precursors were precipitated either with NaOH or tetrabutylammonium hydroxide (TBAOH). Al was used as an element facilitating Htlc structure formation, and Ce and/or Zr were added as promoters. The composites calcined at 600 °C are mesoporous structures with similar textural characteristics. The copper–manganite spinel phases formed from the TBAOH-precipitated precursors are less crystalline and more susceptible to reduction than the counterparts obtained from the precursors synthesized with NaOH. The Cu–Mn-based composites are active in the combustion of toluene, and their performance improves further upon the addition of promoters in the following order: Ce < Zr < Zr + Ce. The composites whose active phases are prepared with TBAOH are more active than their counterparts obtained with the use of the precursors precipitated with NaOH, due to the better reducibility of the less crystalline mixed oxide active phase.

Los estilos APA, Harvard, Vancouver, ISO, etc.

40

Liu, Zirou, Xinhang Xu, Li Guo, Qiusong Chen y Chongchong Qi. "Characterization, Concentration, and Speciation of Metal Elements in Copper Slag: Implications for Secondary Metal Recovery". Crystals 14, n.º 5 (29 de abril de 2024): 420. http://dx.doi.org/10.3390/cryst14050420.

Texto completo

Resumen

The treatment of large amounts of copper slag is an unavoidable issue resulting from the high demand for copper during the global transition to a sustainable development path. Metal-rich copper slag might serve as a potential source of metals through secondary recovery. In this study, two copper slags (CS1 and CS2) with different metallurgical properties were characterized, focusing on secondary metal recovery. The X-ray diffraction (XRD) results show that fayalite (Fe2SiO4) and magnetite (Fe3O4) were the main crystalline phases in both CS1 and CS2. In addition, CS2 exhibited a more stable amorphous silicate network than CS1, which was attributed to the differences in the content of Si-O-3NBO linkages. The sequential extraction of Zn, Cu, Fe, and Pb from the slags was also explored, with the Cu content in CS1 being substantially lower than that in CS2. All metals were distributed in the F5 residue fraction. Cu was the most mobile metal as a result of the large proportion of soluble fractions (F1–F3), followed by Zn and Fe. This study explored the chemical speciation of Zn, Cu, Fe, and Pb from copper slags, which has practical implications for secondary metal recovery from such materials.

Los estilos APA, Harvard, Vancouver, ISO, etc.

41

Ochoa, M. Nieves Corella, Geoffrey J. T. Cooper, Graham N. Newton, De-Liang Long, Georg Seeber y Leroy Cronin. "Supramolecular Architectures of Copper(II) Perchlorate Complexes of cis,trans-1,3,5-Triaminocyclohexane Assembled Exploiting the Delicate Balance Between Weak and Strong Interactions". Zeitschrift für Naturforschung B 65, n.º 3 (1 de marzo de 2010): 304–10. http://dx.doi.org/10.1515/znb-2010-0312.

Texto completo

Resumen

The complexation of copper(II) perchlorate with cis,trans-1,3,5-triamino-cyclohexane (transtachH) yields four related mononuclear complexes, [Cu(trans-tachH)2](ClO4)4・(H2O) (1), [Cu(transtachH) 2](ClO4)4・2MeOH (2), [Cu(trans-tachH)2(ClO4)](ClO4)3 (3) and [Cu(trans-tach)(transtachH)( ClO4)2](ClO4)・H2O (4). These complexes only differ with respect to ligand protonation, solvent coordination / content, and counterion binding, yet these small differences manifest as vast differences in the supramolecular structures, and we also show that certain crystalline phases of these four compounds persist for different lengths of time in the mother liquor.

Los estilos APA, Harvard, Vancouver, ISO, etc.

42

Ibn-Elhaj, M., D. Guillon y A. Skoulios. "Volumetric and x-ray investigations of the crystalline and columnar phases of copper (II) soaps under pressure". Physical Review A 46, n.º 12 (1 de diciembre de 1992): 7643–51. http://dx.doi.org/10.1103/physreva.46.7643.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

43

Halin, Dewi Suriyani Che, Ibrahim Abu Talib, Abdul Razak Daud y Muhammad Azmi Abdul Hamid. "Effect of Annealing Atmosphere on the Morphology of Copper Oxide Thin Films Deposited on TiO₂ Substrates Prepared by Sol-Gel Process". Key Engineering Materials 594-595 (diciembre de 2013): 113–17. http://dx.doi.org/10.4028/www.scientific.net/kem.594-595.113.

Texto completo

Resumen

Copper oxide films were prepared via sol-gel like spin coating starting from methanolic solutions of cupric chloride onto the TiO2 substrates. Films were obtained by spin coating under room conditions (temperature, 25-30 °C) and were subsequently annealed at different temperatures (200-400 °C) in oxidizing (air) and inert (N2) atmospheres. X-ray diffraction (XRD) patterns showed crystalline phases, which were observed as a function of the annealing conditions. The film composition resulted single or multi-phasic depending on both temperature and atmosphere. The grain size of film was measured using scanning electron microscopy (SEM) and the surface roughness of thin films was characterized by atomic force microscopy (AFM). The grain size of which was annealed in air at 300 °C was 30.39 nm with the surface roughness of 96.16 nm. The effects of annealing atmosphere on the structure and morphology of copper oxide thin films are reported.

Los estilos APA, Harvard, Vancouver, ISO, etc.

44

Triveño Rios, Carlos y R. Contieri. "Crystallization of Amorphous Cu_49.7Ti_31.8Zr_11.3Ni_7.2 Alloy". Materials Science Forum 869 (agosto de 2016): 464–69. http://dx.doi.org/10.4028/www.scientific.net/msf.869.464.

Texto completo

Resumen

Bulk metallic glasses are attractive materials for structural and functional applications when compared to crystalline materials. The Cu-based glasses exhibit particular interest due primarily to their relatively low cost and high fracture resistance. In this work the Cu49.7Ti31.8Zr11.3Ni7.2 alloy was prepared from the mixture of pure metals by arc melting and following the ingot was re-melted by centrifugal casting in wedge-section copper mould. The structure of wedge bulk sample was evaluated by a combination of X-Ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC). The results show that the amorphous state is formed in the thinner region and it is maintained up to thickness of 3.5 mm in the wedge bulk-sample. The crystallization temperature was observed above 400 °C coinciding with the studies of thermal crystallization by XRD and DSC. Dynamical heating of the amorphous phase from room temperature up to 750°C showed the formation of CuTi, Cu10Zr7 e Cu2TiZr crystalline phases.

Los estilos APA, Harvard, Vancouver, ISO, etc.

45

Kozieł, T., J. Latuch y A. Zielińska-Lipiec. "Structure of the Amorphous-Crystalline Fe66Cu6B19Si5Nb4 Alloy Obtained by the Melt-Spinning Process". Archives of Metallurgy and Materials 58, n.º 2 (1 de junio de 2013): 601–5. http://dx.doi.org/10.2478/amm-2013-0044.

Texto completo

Resumen

This paper presents structure investigations of the rapidly cooled Fe66Cu6B19Si5Nb4 alloy. A proper selection of chemical composition enabled in-situ formation of the amorphous-crystalline composite during the melt spinning process. Liquid phase separation into the Fe-rich and the Cu-rich phases was confirmed. The microstructures of alloy, melt-spun from 1723 and 1773 K, are composed of the Fe-rich amorphous matrix and Cu-rich spherical crystalline precipitates. For the higher melt-ejection temperature, no coarse precipitates could be observed. Amorphous nature of the Fe-rich matrix was confirmed by presence of a broad diffraction maximum on the X-ray diffraction patterns, a halo ring on the electron diffraction pattern as well as presence of exothermic effects, related to the crystallization of the Fe-rich amorphous matrix, in the differential scanning calorymetry. Beside presence of copper, revealing positive heat of mixing with iron, relatively large supercooled liquid region, was noticed.

Los estilos APA, Harvard, Vancouver, ISO, etc.

46

Paul, Henryk, Piotr Bobrowski, Robert Chulist, Magdalena M. Miszczyk y Mariusz Prazmowski. "Microstructure Development in the Bonding Zone of Explosively Welded Ti and Cu Sheets". Materials Science Forum 1016 (enero de 2021): 1114–20. http://dx.doi.org/10.4028/www.scientific.net/msf.1016.1114.

Texto completo

Resumen

The interplay of various hardening and softening processes during explosive welding and post-processing annealing have been analysed in titanium/copper bimetallic sheets using scanning electron microscopy and microhardness measurements. Severe plastic deformation and intermetallics’ formation are typical processes leading to hardening, whereas dynamic/static recrystallization and the transformation of amorphous phases into crystalline ones lead to softening. In the as-welded state the interfacial layers of both parent sheets are severely deformed. However, they can undergo intense recrystalization in areas near large melted zones. Inside the melted zones a wide variety of chemical compositions can be detected, however, most of the phases do not appear in the Ti-Cu equilibrium phase diagram. The post-processing annealing at 973 K for 1 h leads to full recrystallization of severely deformed layers of parent sheets and transforms the non-equilibrium phases forming melted zone into the equilibrium TiCu4 and Ti3Cu4 ones via spinodal decomposition. Simultaneously, the growth of four intermetallic layers: Ti2Cu, TiCu, Ti3Cu4, TiCu4 situated along the whole interface was detected.

Los estilos APA, Harvard, Vancouver, ISO, etc.

47

Chen, Jiunn, Yi-Shao Lai, Ping-Feng Yang, Chung-Yuan Ren y Di-Jing Huang. "Structural and elastic properties of Cu6Sn5 and Cu3Snfrom first-principles calculations". Journal of Materials Research 24, n.º 7 (julio de 2009): 2361–72. http://dx.doi.org/10.1557/jmr.2009.0273.

Texto completo

Resumen

We investigated the elastic properties of two tin-copper crystalline phases, the η′-Cu6Sn5 and ε-Cu3Sn, which are often encountered in microelectronic packaging applications. The full elastic stiffness of both phases is determined based on strain-energy relations using first-principles calculations. The computed results show the elastic anisotropy of both phases that cannot be resolved from experiments. Our results, suggesting both phases have the greatest stiffness along the c direction, particularly showed the unique in-plane elastic anisotropy associated with the lattice modulation of the Cu3Sn superstructure. The polycrystalline moduli obtained using the Voigt-Reuss scheme are 125.98 GPa for Cu6Sn5 and 134.16 GPa for Cu3Sn. Our data analysis indicates that the smaller elastic moduli of Cu6Sn5 are attributed to the direct Sn–Sn bond in Cu6Sn5. We reassert the elastic modulus and hardness of both phases using the nanoindentation experiment for our calculation benchmark. Interestingly, the computed polycrystalline elastic modulus of Cu6Sn5 seems to be overestimated, whereas that of Cu3Sn falls nicely in the range of reported data. Based on the observations, the elastic modulus of Cu6Sn5 obtained from nanoindentation tests admit the microstructure effect that is absent for Cu3Sn is concluded. Our analysis of electronic structure shows that the intrinsic hardness and elastic modulus of both phases are dominated by electronic structure and atomic lattice structure, respectively.

Los estilos APA, Harvard, Vancouver, ISO, etc.

48

Catto, F. L., A. H. G. Gabriel, C. Bolfarini, Claudio Shyinti Kiminami y Conrado Ramos Moreira Afonso. "Rapid Solidification and Laser Cladding of Gas Atomized Ni-Nb-Sn Bulk Metallic Glass". Materials Science Forum 899 (julio de 2017): 311–16. http://dx.doi.org/10.4028/www.scientific.net/msf.899.311.

Texto completo

Resumen

Glassy overspray powders of Ni59Nb35Sn6 (at%) bulk metallic glass (BMG) obtained by spray forming were used in order to produce coatings on AISI 1020 mild steel substrate by laser cladding of the pre-placed powders. Different laser parameters, resulting in a variation of the power density, PD (J/mm2), were tested with a Yb fiber laser (up to 500 W). Gas atomized powders, suction cast sample trough copper mold casting and the laser clad tracks were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and coatings were subjected to measurements of Vickers microhardness. Atomized powder obtained showed no crystalline phases formation up to 425 μm, indicating good glass forming ability (GFA) of Ni59Nb35Sn6 (at%) alloy. Microstructure characterization confirmed maximum glassy dimension of tc =1mm for the Ni59Nb35Sn6 (at%). Laser cladding track showed nanocrystalline phases embedded in a glassy matrix with Vickers microhardness ranging from 336 to 1184 HV.

Los estilos APA, Harvard, Vancouver, ISO, etc.

49

Yasin, Sahl, Salma Hamid, Mohammed Sulieman Ali Eltoum, Abdalsakhi S. M Hamed y Mohammed Alzubair Almaleeh. "A Unique Modified Eggshell Method as a Model to Reduce and Remove Copper(II) from Aqueous Solutions for Water Treatment". Oriental Journal Of Chemistry 39, n.º 3 (30 de junio de 2023): 694–702. http://dx.doi.org/10.13005/ojc/390320.

Texto completo

Resumen

The aim of this study was to investigate the removal of Cu2+ using eggshells and iron-modified eggshells. Batch adsorption experiments were conducted to assess the impact of various operational parameters, including contact time, pH, isotherms, and kinetics. The samples were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS). XRD analysis confirmed the presence of crystalline phases, specifically trigonal and hexagonal structures, in both eggshell samples. The addition of iron resulted in a reduction in the average crystallite size from 33.157 nm to 16.086 nm. The FTIR spectra exhibited a carbonyl peak at 1804 cm-1. The results indicated that Cu2+ adsorption on eggshells occurred rapidly, reaching equilibrium within 80 min, with an optimal pH range of 6.0 to 7.0. Furthermore, the modified eggshells demonstrated superior Cu2+ removal compared to unmodified eggshells due to the increased external surface area. The copper concentration on the eggshell surface increased from 0% to 94.58%, suggesting an ion exchange between iron and copper within the modified eggshell. The experimental data exhibited a better fit with the Freundlich isotherm model, indicating the presence of heterogeneous adsorption sites for Cu2+. The kinetics of adsorption followed a pseudo-second-order rate equation. This study highlights the efficacy of using eggshells, particularly iron-modified eggshells, as a cost-effective and accessible method for the efficient removal of heavy metals like Cu2+ from drinking water or industrial wastewater.

Los estilos APA, Harvard, Vancouver, ISO, etc.

50

Finkelman, Robert B., Henry R. Dodds, Naomi T. Nichols y Glenn B. Stracher. "Coal Fire Sublimates: Are We Missing Something?" Sustainability 15, n.º 23 (24 de noviembre de 2023): 16262. http://dx.doi.org/10.3390/su152316262.

Texto completo

Resumen

Uncontrolled coal fires present a nearly unparalleled environmental and human health disaster. These fires can cause the destruction of the ecosystem, ignite forest fires, become a source of windblown dust and siltation of streams, and pollute surface water, ground water, and crops. They can cause significant disruption of families and communities resulting from physical hazards of collapse or explosion, excessive heat, visual blight and loss of potentially valuable acreage, deterioration of cultural infrastructure, personal and public property, and loss of a valuable energy resource. The emission of CO2 and other greenhouse gases presents a significant health hazard due to respiration of dust and aerosols, and exposure to acidic gases, potentially toxic trace elements, and organic compounds. Numerous studies have described many dozens of phases that have condensed from the effluents of these fires. However, many of these studies may have overlooked the nano- and ultra-fine particles that exist beside, in, and under the brightly colored, often spectacular crystalline macro phases. Using a scanning electron microscope with an energy dispersive X-ray detector we examined a small (30 mm × 10 mm) piece of condensate from an uncontrolled coal fire in the Jharia region of India and found more than 30 different phases in this one small piece. The phases included ammonium, copper, iron, lead, bismuth chlorides; bismuth, lead, and ammonium silici-fluorides; ammonium and lead iodates; iron, barium, lead, copper, and zinc sulfides; iron and silicon oxides; and others. Broken fragments revealed multiple generations of phases. Though not strictly nanoparticles (smaller than 0.1 μm), many of these particles are in the micrometer to sub-micron range and it is likely that there are phases present in the nanoparticle size range. Certainly, particulates in the nanoparticle and ultra-fine particle range are being released from the uncontrolled coal fires and may be impacting the environment and the health of the mine workers and nearby residents, an issue that should be investigated.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Artículos de revistas sobre el tema "Copper crystalline phases"

Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros