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1
Content available Hydrothermal Synthesis, Impedance and Optical Properties of Tm-Doped SrBi2Nb2O9 Ceramics
Afqir Mohamed, Stojadinović Stevan, Elaatmani Mohamed, Zegzouti Abdelouahad, Tahiri Nabiha, Daoud Mohamed
Archives of Metallurgy and Materials
|
2022
|
Vol. 67, iss. 1
45--50
EN
In this study, Strontium Bismuth Niobate (SrBi2-xTmxNb2O9 with 0 ≤ x ≤ 0.1) doped by Tm was synthesized using by the hydrothermal method. The microstructure and electrical properties were mainly investigated. XRD analysis showed a single-phase orthorhombic structure for Tm-doped SrBi2Nb2O9 samples. The crystallite size is anisotropic and the strain is apparently independent of Tm amount. Dielectric properties for doped SrBi2Nb2O9 with Tm3+ ion have the same trend discussed for the pure sample. FTIR resulats showed that NbO6 octahedral is formed, on one hand, and on the other hand, it shows that spectras for doped and undoped samples are nearly the same. The Cross-section of ceramics showed the plate-like morphology, also the distribution of the pore in ceramics are observed for all samples. Tm dopants produce only minor changes in the impendence parameter values at room temperature. The luminescent (PL) properties of Tm-doped SrBi2Nb2O9 ceramic powders were investigated. The optimum Tm3+ concentration for the maximum PL intensity was found to be at x = 0.075.
2
Content available Effect of Reaction Time and Heat Treatment in the Production of Hydroxyapatite by Hydrothermal Synthesis
Kati Nida, Ozan Sermin, Yildiz Tülay, Arslan Mehmet
Archives of Metallurgy and Materials
|
2022
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Vol. 67, iss. 4
1427--1434
EN
In the present work, Hydroxyapatite synthesis was carried out using hydrothermal method with calcium nitrate tetrahydrate (Ca(NO3)2.4H2O) and fosfor pentaoksit (P2O5) as precursors. For the hydrothermal method, constant reaction temperature (180°C) and different reaction times (6 hours, 12 hours, 18 hours and 24 hours) were determined. The samples produced were divided into two groups. Four samples were not heat treatment; four samples were heat treatment at 700°C for 1 hour. The obtained products were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) techniques, X-ray diffraction (XRD) and UV-Vis spectrometer. SEM photos showed that the Hydroxyapatite powders produced are in the form of the agglomerate. According to EDS results, Hydroxyapatite samples are of high purity. XRD’s findings confirm that the diffraction peaks correspond to the pure phase of Hydroxyapatite. A general decrease was observed in the energy band gap of the samples with increasing hydrothermal reaction time.
3
Content available Geochemical and tectonic characteristics of manganese mineralization in the Yozgat region, Turkey
Öksüz Nursel, Koçak İsmail, Temiz Uğur
Geological Quarterly
|
2021
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Vol. 65, No. 2
art. no. 31
EN
North of the Central Anatolian Crystalline Complex and bordered by the İzmir-Ankara-Erzincan Suture Zone, mineralization occurs within ophiolites known as Anatolian Ophiolite Complex. The mineralization is present within banded, laminated and lenticular radiolarites which are intensely fractured and folded. It is distributed around Derbent, Baltasarilar, Cihanpasa, Buyukmahal, Eymir and Kadisehri where pyrolusite, psilomelane, manganite and braunite comprise the main paragenesis and jacobsite, magnetite, limonite and goethite are minor phases. The negative Eu anomaly suggests that the hydrothermal source was distant from the mineralization area or was mixed with seawater. All samples from the Cihanpasa and Buyukmahal areas have a negative Ce anomaly and resemble low-temperature hydrothermal mineral deposits. Samples from other locations (Derbent, Baltasarilar, Cihanpasa, Eymir, Buyukmahal, Tarhana) are characterized by both negative and positive Ce anomalies. From this it can be inferred that both hydrothermal and hydrogenetic processes were active in mineralization. High Ba contents and a LREE-enriched pattern together with negative Ce anomalies and trace element distributions indicate that the mineralization in the area was derived from a primary hydrothermal source. In addition, diagenetic and epigenetic processes may also have played an important role in the manganese mineralization.
4
Content available Loading Effect of Ag Nanoparticles on Photocatalytic Activity of TiO2 Nanorod Arrays Prepared by Hydrothermal Method
Lee Kwangmin, Yoo Daeheung, Zakiyuddin Ahmad
Archives of Metallurgy and Materials
|
2021
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Vol. 66, iss. 3
751--754
EN
Rutile-TiO2 nanorod thin films were formed on Ti disks via alkali treatment in NaOH solutions followed by heat treatment at 700°C. Ag nanoparticles were loaded on nanorods using a photo-reduction method to improve the photocatalytic properties of the prepared specimen. The surface characterization and the photo-electrochemical properties of the Ag-loaded TiO2 nanorods were investigated using a field-emission scanning electron microscope (FE-SEM), X-ray photoelectron spectroscopy (XPS), UV-Vis spectroscopy and electrochemical impedance spectroscopy (EIS). The TiO2 nanorods obtained after the heat treatment were 80 to 180 nm thick and 1 μm long. The thickness of the nanorods increased with the NaOH concentration. The UV-Vis spectra exhibit a shift in the absorption edge of the Ag-loaded TiO2 to the visible light range and further narrowing of the bandgap. The decrease in the size of the capacitive loops in the EIS spectra showed that the Ag loading effectively improved the photocatalytic activity of the TiO2 nanorods.
5
Content available Chemically Modified Cellulose Capped Zinc Oxide Nanocomposite: Spectral and Optical Properties
Jagadeeswari R., Selvakumar P., Jeevanantham V., Saravanan R.
Archives of Metallurgy and Materials
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2021
|
Vol. 66, iss. 3
911--915
EN
In this study, a new chemically modified cellulose polymer-capped ZnO nanopowder prepared by hydrothermal method using chemically modified cellulose polymer as capping agent was successfully reported. The structural characteristics of CMC-capped ZnO nanopowder was reported by FTIR, XRD, SEM and EDX studies. XRD results revealed crystallographic properties like crystal composition, phase purity and crystallite size of the prepared CMC-capped ZnO nanopowder and average size calculated by Debye Scherrer formula as 14.66 nm. EDX studies revealed that the presence of elemental compositions of capping agent in the nanopowder samples. The optical characterization of the CMC-capped ZnO nanopowder was studied using UV absorption (λ max = 303 nm) and PL spectroscopy (λ ex = 295 nm). The average crystal diameter and grain size were calculated by effective mass approximation formula and compared with XRD findings that agreed well and verified CMC capped ZnO with particle size of 193 nm. Thus, the promising optical characteristics shown by the synthesized CMC capped ZnO nanopowders exposes its potential usage in bio-medical fields.
6
Content available Hydrothermal Synthesis of Highly Uniform Chalcopyrite CuFeS2 Nanoparticles
Sabet Mohammad, Mahdavi Kamran, Salmeh Fahimeh
Archives of Metallurgy and Materials
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2020
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Vol. 65, iss. 2
595--600
EN
In this research work, high uniform CuFeS2 chalcopyrite with 20-40 nm particles were synthesized via a simple hydrothermal method. Different analysis were used to characterize the obtained product such as X-ray diffraction pattern (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermal gravimetric analysis (TGA). The photocatalytic activity of the product was investigated by degradation three different dyes namely acid brown, acid red and methylene blue. The results showed the synthesized CuFeS2 nanoparticles have high photocatalytic activity and can degrade the used dyes in large quantities.
7
Content available Facile synthesis of chitosan/CuO nanocomposites for potential use as biocontrol agents
Siriphannon P., Iamphaojeen Y.
Bulletin of the Polish Academy of Sciences. Technical Sciences
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2018
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Vol. 66, nr 3
311--316
EN
Chitosan/CuO nanocomposites (Chi/CuO) were prepared by facile and eco-friendly technique. The 2%w/v chitosan solution was mixed with 0.5 %w/w sodium tripolyphosphate (STPP), resulting in the formation of ionically crosslinked chitosan. The crosslinked chitosan was soaked in an aqueous solution containing 0.001, 0.01 or 0.1 mol/L CuSO4·5H2O for 24 hrs, in which the Cu2+ ions were absorbed into the chitosan network, forming as the chitosan/Cu2+ precursors. The chitosan/Cu2+ precursors were hydrothermally reacted in two different basic media, i.e. NaOH and NH4OH, at 100°C for 24 hrs, resulting in the nano-sized CuO crystals hydrothermally grew and embedded in the crosslinked chitosan matrix. The CuO grown in the NaOH possessed larger crystallite size and higher crystallinity than that in the NH4OH. In addition, the CuO crystallite size in the nanocomposites increased with the increase of initial concentration of Cu2+ starting agent due to the increase of Cu2+ quantity in the chitosan/Cu2+ precursors. The chitosan/CuO nanocomposites prepared by using 0.01 and 0.1 mol/L Cu2+ could exhibit the antibacterial activities after intimate contact with Staphylococcus aureus and Escherichia coli under JIS L 1902:1998 (Qualitative) test method, indicating their potential use as biocontrol agents.
8
Template Assisted Growth of Molybdenum Oxide Nanocrystals Through Hydrothermal Process
Farzaneh F., Najafi M.
Polish Journal of Chemistry
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2009
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Vol. 83, nr 9
1523-1528
EN
Rod shaped MoO3 nanocrystals were prepared from ammonium heptamolybdate tetra - hydrate (AHM) and ethylene diamine (en) as template agent in water via a hydrothermal process at 180 graduate C. The prepared nanocrystals were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The range size of nanorods are from a few nanometers (nm) to micrometers in length and 50 to 200 nm in diameter. It was also found that nanostructures of varied dimensionality such as plates and helical plates are formed using citric acid (CA), and starch as template respectively.
9
Content available remote Preparation of ZrO2:Tb via microwave hydrothermal method
Kaszewski J., Łojkowski W., Narkiewicz U.
Optica Applicata
|
2009
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Vol. 39, nr 4
773-779
EN
Terbium doped zirconium dioxide was successfully synthesized using microwave hydrothermal method. The powder is strongly agglomerated and has mean crystallite size around 6 nm. The density of obtained powders is significantly lower than density of bulk zirconium dioxide indicating the existence of zirconium and dopant hydroxides remaining after the hydrothermal process. The effect of terbium on morphology, phase composition, specific surface area and density of the samples was determined.
10
Content available remote Hydroxyapatite coated dental implants by sputtering technique
Ozeki K., Fukui Y., Aoki H.
Biocybernetics and Biomedical Engineering
|
2006
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Vol. 26, no. 1
95-101
EN
Hydroxyapatite (HA) was coated onto titanium substrates using radio frequency sputtering, and the coated HA films were crystallized in autocIave at 110°C using the low temperature hydtrothermal method. In pull-out tests, the adhesion strength of the sputtered film to the substrate increased from 1.9 : 0.2 to 5.3 : 1.6 MPa after the hydrothermal treatment. Sputtered films subjected to the hydrothermal treatment and plasma-sprayed coating on titanium columns were implanted in the diaphysis of the femora of six adult dogs, and pull-out tests were carried out after two, four, and 12 weeks. The sputtered film showed a higher bone bonding strength than the plasma-sprayed coating at the same periods. The coated implants were also placed into mandibles for 2,4, 12 and 24 weeks for histological examination. In the histological examination, connective tissue was noted after 2 and 4 weeks around the controls, whereas, in the sputter-coated implant, new bone formation was noted after 2 and 4 weeks, without any connective tissue.
11
Content available remote Fundamentals on inorganic membranes: present and new developments
Larbot A. B.
Polish Journal of Chemical Technology
|
2003
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Vol. 5, nr 2
8-13
EN
The classical methods for preparing ceramic membranes from macroporous support to microporous or dense layers, as extrusion, suspended powder method, sol-gel processes, will be described. But other techniques are also used as chemical vapour deposition or electroless for dense or microporous membranes, hydrothermal treatment to elaborate zeolite layers will be also described. Hollow fibers, a new configuration for ceramic membranes will be presented.
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