PHOTOLUMINESCENCE OF NON-CRYSTALLINE ALUMINA NANOWIRES SYNTHESIZED BY DIRECT ANODIZATION OF ALUMINUM

2009 ◽  
Vol 23 (14) ◽  
pp. 1819-1825
Author(s):  
JAYA SARKAR ◽  
GOBINDA GOPAL KHAN ◽  
A. BASUMALLICK
Keyword(s):  
Light Emission ◽  
Pure Aluminum ◽  
Bath Temperature ◽  
Constant Current ◽  
X Ray Diffraction ◽  
Constant Current Density ◽  
X Ray ◽  
Anodization Process ◽  
Potential Applications ◽  
Crystalline Alumina

Alumina nanowires have been synthesized by a simple electrochemical route, by tailoring the anodization process of aluminum. Two-stage anodization of pure aluminum foils were carried out in 0.3 M oxalic acid electrolyte by maintaining a constant current density of 250 A/m2 and suitably controlling the other anodization parameters: anodization voltage, bath temperature and anodization time. The fabricated alumina nanowires were investigated by field-emission scanning electron microscope (FE-SEM) and energy dispersive X-ray spectroscopy (EDS). Moreover, the X-ray diffraction (XRD) study on the prepared nanowires shows that they are non-crystalline in nature. The photoluminescence (PL) spectra of alumina nanowires exhibit two stable emission bands at 438 and 581 nm. The blue luminescence behavior of the alumina nanowires are attributed to the oxygen-deficient defect centers. PL study of alumina nanowires shows that they have potential applications in light emission devices.

scholarly journals Luminescence Performance of Yellow Phosphor SrxBa1−xTiO3: Eu3+, Gd3+for Blue Chip

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Limin Dong ◽  
Jian Li ◽  
Qin Li ◽  
Lianwei Shan ◽  
Zhidong Han
Keyword(s):  
Light Emission ◽  
Solid Phase ◽  
Phase Method ◽  
Photoluminescence Excitation ◽  
X Ray Diffraction ◽  
Yellow Light ◽  
X Ray ◽  
Potential Applications ◽  
Solid Phase Method ◽  
Luminescence Performance

The SrxBa1−xTiO3: Eu3+, Gd3+phosphors are synthesized by high temperature solid-phase method. Multiple techniques including X-ray diffraction (XRD), and scanning electron microscopy (SEM) are used to examine the surface morphology and structural properties of SrxBa1−xTiO3: Eu3+, Gd3+phosphors. The optical properties are presented and discussed in terms of photoluminescence (PL) and photoluminescence excitation (PLE) spectra. The as-obtained SrxBa1−xTiO3: Eu3+, Gd3+phosphors show higher PL emission intensity (at 591, 611 nm). The peaks at 591 and 611 nm are attributed to Eu3+  5D0-7F1,5D0-7F2. Gd3+has a strong sensitization on Eu3+. A certain amount of Sr2+and Ba2+is contributed to the intensity of light emission. After being irradiated with blue light, the phosphor samples emit yellow light. This suggests its potential applications in many fields.

scholarly journals A Research on Niw Alloy Coatings on Mild Steel through Electrodeposition Method

2019 ◽  
Vol 8 (9S2) ◽  
pp. 442-445
Keyword(s):  
Mechanical Properties ◽  
Mild Steel ◽  
Deposition Time ◽  
Wear Behavior ◽  
Hardness Test ◽  
Bath Temperature ◽  
Constant Current ◽  
X Ray Diffraction ◽  
Constant Current Density ◽  
Pin On Disc

In order to enhance the structural and mechanical properties of mild steel, NiW nanocrystalline thin layer has been coated on the surface of mild steel through electroplating technique at bath temperature of 40 C over the deposition time of 45 minutes. The nanocrystalline NiW alloy coatings were deposited on mild steel at constant current density of 1 A/dm2 . The structural and chemical characterizations of the NiW alloy coated mild steel were performed by scanning electron microscopy (SEM) and X-ray diffraction pattern (XRD). The micro hardness value of the coated mild steel was determined by using Vickers Hardness test. The effect of NiW on wear behavior of mild steel was analyzed using Pin-on-disc apparatus. The mechanical properties of mild steel such as hardness, roughness and wear resistance have been enhanced in an appreciable manner. This is primarily due to the NiW alloy coatings on mild steel. The variations in structural and mechanical properties of NiW coated mild steel were also studied

Study of Hydroxyapatite/Al2O3 (anodic) Biocomposite Coating on Titanium with a Novel Multi-Step Method

2006 ◽  
Vol 312 ◽  
pp. 257-262
Author(s):  
Li Ping He ◽  
Zhen Jun Wu ◽  
Zong Zhang Chen ◽  
Yiu Wing Mai
Keyword(s):  
Hydrothermal Treatment ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Energy Dispersive Spectrometry ◽  
Constant Current ◽  
X Ray Diffraction ◽  
Step Method ◽  
Constant Current Density ◽  
X Ray ◽  
Scanning Electron

A novel hydroxyapatite/Al2O3 (anodic) biocomposite coating has been successfully fabricated on titanium using a multi-step technique including physical vapor deposition (PVD), anodization, electrodeposition and hydrothermal treatment. Scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and X-ray diffraction (XRD) were employed to investigate morphologies and compositions of the pre- and post-hydrothermally treated hydroxyapatite/Al2O3 (anodic) biocomposite coatings. The results showed that plate-like Ca-deficient hydroxyapatite coating was directly elctrodeposited onto anodic Al2O3 at a constant current density of 2.0 mA/cm2 using NaH2PO4 as the phosphorous source. The plate-like Ca-deficient hydroxyapatite was converted into network-like Ca-rich hydroxyapatite after hydrothermal treatment.

Electrochemical Performance of Nanocrystalline Zinc Ferrite Films Synthesized Using Electrodeposition

2020 ◽  
Vol 835 ◽  
pp. 1-6
Author(s):  
E. Mostafa Elsayed ◽  
Mohamed M. Rashad ◽  
H.F.Y. Khalil ◽  
M.R. Hussein ◽  
M.M.B. El-Sabbah ◽  
...  
Keyword(s):  
Zinc Ferrite ◽  
Room Temperature ◽  
Crystal Size ◽  
Bath Temperature ◽  
Alloy Film ◽  
X Ray Diffraction ◽  
X Ray ◽  
Anodization Process ◽  
Sem Micrograph ◽  
Deposited Film

Nanocrystalline spinel zinc ferrite ZnFe2O4 thin film has been studied and synthesized via the electrodeposition-anodization process. Electrodeposited ZnFe2 alloys were obtained from aqueous sulphate bath. The resulted alloys were electrochemically oxidized in strong alkaline solution (1 M KOH) at room temperature to the analogous hydroxides. The electroanodized ZnFe2 alloy film was annealed in air at 400 °C for 2 h to get the required zinc ferrite. The electrochemical factors controlling of the electrodeposition of ZnFe2 alloys such as the bath temperature, agitation, the current density were studied and optimized. The crystal structure, crystal size and microstructure of the produced ferrites were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The deposited film was mainly composed of ZnFe2O4 based on XRD studies. The produced film had a spinel structure and the crystallite size was 4.9 nm. SEM micrograph of the resulted zinc ferrite particles shows compact crystallites shapes and agglomerated chains with smallest semicircular particles like morphology.

scholarly journals Laser-Induced Deposition of Plasmonic Ag and Pt Nanoparticles, and Periodic Arrays

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 10
Author(s):  
Daria V. Mamonova ◽  
Anna A. Vasileva ◽  
Yuri V. Petrov ◽  
Denis V. Danilov ◽  
Ilya E. Kolesnikov ◽  
...  
Keyword(s):  
Substrate Surface ◽  
Pt Nanoparticles ◽  
Single Step ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
X Ray ◽  
Periodic Arrays ◽  
Potential Applications ◽  
Surface Decoration ◽  
Wide Potential

Surfaces functionalized with metal nanoparticles (NPs) are of great interest due to their wide potential applications in sensing, biomedicine, nanophotonics, etc. However, the precisely controllable decoration with plasmonic nanoparticles requires sophisticated techniques that are often multistep and complex. Here, we present a laser-induced deposition (LID) approach allowing for single-step surface decoration with NPs of controllable composition, morphology, and spatial distribution. The formation of Ag, Pt, and mixed Ag-Pt nanoparticles on a substrate surface was successfully demonstrated as a result of the LID process from commercially available precursors. The deposited nanoparticles were characterized with SEM, TEM, EDX, X-ray diffraction, and UV-VIS absorption spectroscopy, which confirmed the formation of crystalline nanoparticles of Pt (3–5 nm) and Ag (ca. 100 nm) with plasmonic properties. The advantageous features of the LID process allow us to demonstrate the spatially selective deposition of plasmonic NPs in a laser interference pattern, and thereby, the formation of periodic arrays of Ag NPs forming diffraction grating

scholarly journals Synthesis of Three-Dimensional Fe3O4/Graphene Aerogels for the Removal of Arsenic Ions from Water

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Yan Ye ◽  
Da Yin ◽  
Bin Wang ◽  
Qingwen Zhang
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
3D Structure ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Graphene Aerogels ◽  
Transmission Electron ◽  
Potential Applications ◽  
Removal Of Arsenic

We report the synthesis of three-dimensional Fe3O4/graphene aerogels (GAs) and their application for the removal of arsenic (As) ions from water. The morphology and properties of Fe3O4/GAs have been characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and superconducting quantum inference device. The 3D nanostructure shows that iron oxide nanoparticles are decorated on graphene with an interconnected network structure. It is found that Fe3O4/GAs own a capacity of As(V) ions adsorption up to 40.048 mg/g due to their remarkable 3D structure and existence of magnetic Fe3O4nanoparticles for separation. The adsorption isotherm matches well with the Langmuir model and kinetic analysis suggests that the adsorption process is pseudo-second-ordered. In addition to the excellent adsorption capability, Fe3O4/GAs can be easily and effectively separated from water, indicating potential applications in water treatment.

Hydrothermal synthesis, crystal structure and properties of a two-dimensional uranyl coordination polymer based on a flexible zwitterionic ligand

2018 ◽  
Vol 74 (3) ◽  
pp. 366-371 ◽  
Author(s):  
Wen Cui ◽  
Ruyu Wang ◽  
Xi Shu ◽  
Yu Fan ◽  
Yang Liu ◽  
...  
Keyword(s):  
Coordination Polymer ◽  
Hydrothermal Reaction ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Uranyl Compounds ◽  
X Ray ◽  
Potential Applications ◽  
Ft Ir ◽  
Fuel Reprocessing ◽  
Ft Ir Spectroscopy

The interaction between the uranyl cation, (UO2)2+, and organic species is of interest due to the potential applications of the resulting compounds with regard to nuclear waste disposal and nuclear fuel reprocessing. The hydrothermal reaction of various uranyl compounds with flexible zwitterionic 1,1′-[1,4-phenylenebis(methylene)]bis(pyridin-1-ium-4-carboxylate) dihydrochloride (Bpmb·2HCl) in deionized water containing drops of H2SO4resulted in the formation of a novel two-dimensional uranyl coordination polymer, namely poly[tetraoxido{μ2-1,1′-[1,4-phenylenebis(methylene)]bis(pyridin-1-ium-4-carboxylate)}di-μ3-sulfato-diuranium(VI)], [(UO2)2(SO4)2(C20H16N2O4)]n, (1). Single-crystal X-ray diffraction reveals that this coordination polymer exhibits a layered arrangement and the (UO2)2+centre is coordinated by five equatorial O atoms. The structure was further characterized by FT–IR spectroscopy, powder X-ray diffraction (PXRD) and thermogravimetric analysis (TGA). The polymer shows high thermal stability up to 696 K. Furthermore, the photoluminescence properties of (1) has also been studied, showing it to exhibit a typical uranyl fluorescence.

Coating thickness determination in highly absorbent core–shell systems

2012 ◽  
Vol 45 (5) ◽  
pp. 906-913 ◽  
Author(s):  
Herve Palancher ◽  
Anne Bonnin ◽  
Veijo Honkimäki ◽  
Heikki Suhonen ◽  
Peter Cloetens ◽  
...  
Keyword(s):  
Coating Thickness ◽  
Protective Layer ◽  
Test Sample ◽  
High Energy ◽  
Core Shell ◽  
Single Shot ◽  
X Ray Diffraction ◽  
X Ray ◽  
Alloy Particles ◽  
Potential Applications

This article describes a single-shot methodology to derive an average coating thickness in multi-particle core–shell systems exhibiting high X-ray absorption. Powder composed of U–Mo alloy particles surrounded by a micrometre-thick UO2protective layer has been used as a test sample. Combining high-energy X-ray diffraction and laser granulometry, the average shell thickness could be accurately characterized. These results have been validated by additional measurements on single particles by two techniques: X-ray nanotomography and high-energy X-ray diffraction. The presented single-shot approach gives rise to many potential applications on core–shell systems and in particular on as-fabricated heterogeneous nuclear fuels.

Synthesis and Electrochemical Properties of a LiNi0.7Co0.3O1.9Cl0.1 Cathode Material for Lithium-Ion Battery

2007 ◽  
Vol 336-338 ◽  
pp. 463-465 ◽  
Author(s):  
Xin Lu Li ◽  
Fei Yu Kang ◽  
Yong Ping Zheng ◽  
Xiu Juan Shi ◽  
Wan Ci Shen
Keyword(s):  
Hexagonal Lattice ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
Constant Current ◽  
Cyclic Voltammograms ◽  
X Ray Diffraction ◽  
X Ray ◽  
Constant Current Charge ◽  
Initial Cycle ◽  
Partial Oxygen

Partial oxygen in LiNi0.7Co0.3O2 was replaced by chlorine to form LiNi0.7Co0.3O1.9Cl0.1. Phase structure of LiNi0.7Co0.3O1.9Cl0.1 was identified as a pure hexagonal lattice of α-NaFeO2 type by X-ray diffraction. Discharge capacity of LiNi0.7Co0.3O1.9Cl0.1 was 202 mAh/g in initial cycle at 15 mA/g current density in 2.5- 4.3 V potential window. The constant current charge/discharge experiments and cyclic voltammograms showed that chlorine addition was effective to improve reversible capacity and cycle stability of LiNi0.7Co0.3O2.

W-Doped VO2 (M) with Tunable Phase Transition Temperature

2013 ◽  
Vol 320 ◽  
pp. 483-487 ◽  
Author(s):  
Ming Li ◽  
Deng Bing Li ◽  
Jing Pan ◽  
Guang Hai Li
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Variable Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Infrared Transmittance ◽  
Transmission Electron ◽  
Potential Applications

W-doped VO2 (B) nanoneedles were successfully synthesized by solgel combing with hydrothermal treatment, in which the polyethylene glycol (PEG) was used as both surfactant and reducing. The metastable VO2 (B) was completely transformed to thermochromic VO2 (M) after annealing at high purity N2 atmosphere. The DSC results exhibit a strong crystallographic transition, and the phase transition temperature of VO2 (M) can be reduced to about 38 °C by W-doping. Field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) were used to characterize the morphology and crystalline structure of the samples. The variable-temperature infrared transmittance spectra of VO2 (M) demonstrate their potential applications in energy saving field.

Sign in / Sign up

Export Citation Format

Share Document