scholarly journals Aluminium/zirconium alloys obtained by Al underpotential deposition onto Zr from low temperature AlCl3+NaCl molten salts

2019 ◽  
Vol 84 (11) ◽  
pp. 1329-1344
Author(s):  
Vesna Cvetkovic ◽  
Niko Jovicevic ◽  
Natasa Vukicevic ◽  
Jovan Jovicevic
Keyword(s):  
Low Temperature ◽  
Zirconium Alloys ◽  
Linear Sweep Voltammetry ◽  
Underpotential Deposition ◽  
Alloy Formation ◽  
X Ray Diffraction ◽  
Electrode Surfaces ◽  
Chloroaluminate Melt ◽  
Thermal Preparation

Contrary to the widely accepted hypothesis that it is not possible, aluminium underpotential deposition (UPD) onto zirconium from a low temperature (200, 250 and 300?C) equimolar chloroaluminate melt was recorded. Furthermore, it was shown that aluminium UPD facilitates alloy formation between the deposited aluminium monolayer and the zirconium substrate by interdiffusion. The aluminium/zirconium alloys formed at the temperatures substantially lower than those needed for thermal preparation of the same alloys were: Al3Zr2 and Al3Zr. Experimental techniques used were linear sweep voltammetry, potential step, scanning electron microscope, energy dispersive spectroscopy and X-ray diffraction were used for characterization of obtained electrode surfaces.

scholarly journals Alloy formation by Mg underpotential deposition on al from nitrate melts

2015 ◽  
Vol 21 (4) ◽  
pp. 527-536 ◽  
Author(s):  
Vesna Cvetkovic ◽  
Luka Bjelica ◽  
Natasa Vukicevic ◽  
Jovan Jovicevic
Keyword(s):  
Energy Dispersive Spectrometry ◽  
Electrochemical Techniques ◽  
Linear Sweep Voltammetry ◽  
Stripping Voltammetry ◽  
Underpotential Deposition ◽  
Magnesium Nitrate ◽  
Energy Dispersive ◽  
Alloy Formation ◽  
X Ray Diffraction ◽  
X Ray

Magnesium was underpotentially deposited on aluminium electrodes from magnesium nitrate-ammonium nitrate melts at temperatures ranging from 390 K to 500 K. Electrochemical techniques used were linear sweep voltammetry and potential step. Electrodes were studied by Scanning electron microscopy (SEM), Energy dispersive spectrometry (EDS), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). It was found that reduction processes of nitrate, nitrite and water (when present), in the underpotential range studied, took part simultaneously with magnesium underpotential deposition. Consequently, magnesium UPD reduction and stripping voltammetry peaks were not pronounced and well defined. Nevertheless, EDS, EDX and XRD measurements showed evidence of Mg2Al3, MgAl2 and Al12Mg17 alloys formed by underpotential deposition of magnesium onto aluminium substrate.

SYNTHESIS AND CHARACTERIZATION OF NANOCRYSTALLINE FeNi AND Ni3Fe ALLOYS

2011 ◽  
Vol 25 (07) ◽  
pp. 1013-1019 ◽  
Author(s):  
S. AZADEHRANJBAR ◽  
F. KARIMZADEH ◽  
M. H. ENAYATI
Keyword(s):  
Ball Mill ◽  
Morphological Evolution ◽  
Lattice Parameter ◽  
Internal Stresses ◽  
Alloy Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Particles ◽  
Fe Alloys

Nanocrystalline FeNi and Ni 3 Fe alloys were prepared by mechanical alloying of Fe and Ni elemental powders using a planetary ball mill under protection atmosphere. X-ray diffraction measurements were performed to follow alloy formation process in these alloys. A heat treatment of 1 h at 800°C was carried out to relax the internal stresses of the milled samples. Morphological evolution of powder particles was revealed by scanning electron microscopy. The value of lattice parameter was reached to 0.35762 nm and the hardness was found to be 686 HV at 30 h milled FeNi powder. In the case of Ni 3 Fe the values of 0.3554 nm and 720 HV were obtained for lattice parameter and hardness, respectively.

The Preparation and Characterization of LiFe0.98Mn0.02PO4/C by Spray-Drying and Low Temperature Reduction Route

2012 ◽  
Vol 581-582 ◽  
pp. 525-528
Author(s):  
Jia Feng Zhang ◽  
Bao Zhang ◽  
Xue Yi Guo ◽  
He Zhang Chen ◽  
Jian Long Wang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Spray Drying ◽  
Xrd Analysis ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Temperature Reduction ◽  
Co Precipitation ◽  
Low Temperature Reduction

The LiFe0.98Mn0.02PO4/C was synthesized by spray-drying and low temperature reduction route using FePO4•2H2O as precursor, which was prepared by a simple co-precipitation method. The LiFe0.98Mn0.02PO4/C sample was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and electrochemical measurements. The XRD analysis and SEM images show that sample has the good ordered structure and spherical particle. The charge-discharge tests demonstrate that the powder has the better electrochemical properties, with an initial discharge capacity of 162.1 mAh•g−1 and 155.8 mAh•g−1 at current density of 0.1 C and 1C, respectively. The capacity retention reaches 99.4% after 100 cycles at 1C.

Fabrication and Characterization of Alumina/Zirconia Ceramic Compound

2012 ◽  
Vol 724 ◽  
pp. 249-254 ◽  
Author(s):  
Bum Rae Cho ◽  
Ji Hoon Chae ◽  
Bo Lang Kim ◽  
Jong Bong Kang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Low Temperature ◽  
Mechanical Strength ◽  
Sem Analysis ◽  
Zirconia Ceramic ◽  
Sintering Process ◽  
Sintering Aids ◽  
X Ray Diffraction

Sintered ZTA(zirconia toughened alumina) which has good mechanical properties at a low temperature was produced by milling and mixing with Al2O3 and ZrO2(3Y-TZP). In order to examine the effect of sintering aids on the mechanical properties of ZTA, fracture toughness and hardness of the produced ZTA were observed in accordance with change of the added quantity of ZrO2 Scanning electron microscopy and X-ray diffraction technique were applied to observe microstructural change and phase transformation during the process. Experimental results showed that the addition of sintering aids in ZTA at a low temperature induced densification and adding SiO2 and talc lowered sintering temperature and promoted crystallization process of the compound. The mechanical strength of ZTA added ZrO2 showed higher mechanical strength and SEM analysis revealed that Al2O3 and ZrO2 during the sintering process restrained the grain growth each other. Especially, the 92% Al2O3 added sintering aids showed more than 98% of the theoretical density and more than 1500 Hv of hardness value at a low temperature of 1400. It was also showed that the fracture toughness is gradually increasing first and decreasing later in accordance with the quantity of ZrO2.

scholarly journals Preparation and Characterization of Nano-Cadmium Ferrite

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
S. M. Ismail ◽  
Sh. Labib ◽  
S. S. Attallah
Keyword(s):  
Particle Size ◽  
Low Temperature ◽  
Sol Gel ◽  
Stable Phase ◽  
X Ray Diffraction ◽  
Economic Point ◽  
Sol Gel Process ◽  
Pure Phase ◽  
Microstructural Studies

Nano-hematite (α-Fe2O3) and nano-cadmium ferrite (CdFe2O4) are prepared using template-assisted sol-gel method. The prepared samples are analyzed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and Mössbauer spectroscopy techniques for structural and microstructural studies. Nano-α-Fe2O3 with particle size ~60 nm is formed at 500°C, while nano-CdFe2O4 with smaller particle size (~40 nm) is formed at 600°C. It is found that with a simple sol-gel process we can prepare nano-CdFe2O4 with better conditions than other methods: pure phase at lower sintering temperature and time (economic point) and of course with a smaller particle size. So, based on the obtained experimental results, a proposed theoretical model is made to explain the link between the use of the sol-gel process and the formation of nano-CdFe2O4 as a pure phase at low temperature. This model is based on a simple magnetostatic interaction between the formed nuclei within the solution leading to the formation of the stable phase at low temperature.

Preparation at Low-Temperature and Characterization of TiO2 Film Used for Solar Cells

2013 ◽  
Vol 537 ◽  
pp. 205-208
Author(s):  
Xiao Qiang Wang ◽  
Yue Liu Li ◽  
Jian Min Wang ◽  
Jing Guo ◽  
Ming Ya Li
Keyword(s):  
Low Temperature ◽  
Fill Factor ◽  
Sol Gel ◽  
Influence Factors ◽  
Raw Material ◽  
Tetrabutyl Titanate ◽  
X Ray Diffraction ◽  
Glass Substrates ◽  
Photoelectric Properties

In this work, nanocrystalline TiO2 powder was prepared by the sol-gel method via tetrabutyl titanate as raw material, non-ion surfactant TO8 as a template. Then the nanocrystalline TiO2 thin film electrodes which were coated on FTO glass substrates via the slurry consiting of TiO2 powder prepared by us and the trabutyl titanate precursor were successfully prepared by using a simple and convenient hydrothermal method at low temperature. The structure and morphology of powders and films were characterized by X-ray diffraction, scanning electric microscopy. The influence factors on the samples were discussed. The photoelectric properties of cells assembled by the films were measured. The results show that, at 25°C and under 1000W/m2 light intensity，open voltage is 708mV, Jsc is 14.648mA/cm2, fill factor is 53.788, the conversion efficiency is 5.5988%.

scholarly journals Electrodeposition of Nb and Al from chloroaluminate melt on vitreous carbon

10.30544/217 ◽  
2016 ◽  
Vol 22 (2) ◽  
pp. 91-100
Author(s):  
Nataša M. Vukićević ◽  
Vesna S. Cvetković ◽  
Ljiljana S. Jovanović ◽  
Olga S. Radulović ◽  
Jovan N. Jovićević
Keyword(s):  
Anodic Dissolution ◽  
Al Alloys ◽  
Argon Atmosphere ◽  
Vitreous Carbon ◽  
Alloy Formation ◽  
Al Alloy ◽  
Chemical Dissolution ◽  
Reduction Processes ◽  
Chloroaluminate Melt

Niobium and aluminium were electrodeposited at 200 °C under argon atmosphere onto vitreous carbon from inorganic chloroaluminate melts (AlCl3+NaCl) with added niobium. Niobium was introduced into the electrolyte by anodic dissolution of metallic niobium or by chemical dissolution of Nb2O5 in a melt of equimolar AlCl3+NaCl mixture. The processes of deposition/dissolution onto/from vitreous carbon were investigated by cyclic voltammetry and chronoamperometry. Characterization of the obtained deposits was done by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The only observed reduction processes on the working electrode in the potential window from 1.000 V to – 1.000 V vs. Al, were individual niobium deposition and codeposition of niobium and aluminium with Al-Nb alloys formation. Electrodeposition of niobium from the chloroaluminate melt with added niobium (V) oxide seems to start at around – 0.100 V vs. Al and at about – 0.200 V vs. Al aluminium starts codepositing. During the codeposition Nb-Al alloys were formed. Niobium deposition starting potential from the electrolyte with niobium added by anodic dissolution starts at 0.100 V vs. Al, and aluminium codeposition starting potential was at around – 0.025 V vs. Al, followed by Nb/Al alloy formation.

scholarly journals Synthesis and Characterization of Si Oxide Coated Nano Ceria by Hydrolysis, and Hydrothermal Treatment at Low Temperature

2017 ◽  
Vol 62 (2) ◽  
pp. 1125-1129
Author(s):  
M. Kong ◽  
H.W. Kim
Keyword(s):  
Electron Microscopy ◽  
Low Temperature ◽  
Silicon Oxide ◽  
X Ray Diffraction ◽  
Oxide Coatings ◽  
Transmission Electron ◽  
Amorphous Nature ◽  
Simple Growth ◽  
Solution Aggregation

AbstractThe purpose of this work was to the application of Si oxide coatings. This study deals with the preparation of ceria (CeO2) nanoparticles coating with SiO2by water glass and hydrolysis reaction. First, the low temperature hydro-reactions were carried out at 30~100°C. Second, Silicon oxide-coated Nano compounds were obtained by the catalyzing synthesis. CeO2Nano-powders have been successfully synthesized by means of the hydrothermal method, in a low temperature range of 100~200°C. In order to investigate the structure and morphology of the Nano-powders, scanning electron microscopy (SEM) and X-ray diffraction (XRD) were employed. The XRD results revealed the amorphous nature of silica nanoparticles. To analyze the quantity and properties of the compounds coated with Si oxide, transmission electron microscopy (TEM) in conjunction with electron dispersive spectroscopy was used. Finally, it is suggested that the simple growth process is more favorable mechanism than the solution/aggregation process.

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