scholarly journals Electrocatalytic properties and stability of titanium anodes activated by the inorganic sol-gel procedure

2008 ◽  
Vol 73 (11) ◽  
pp. 1083-1112 ◽  
Author(s):  
Vladimir Panic ◽  
Branislav Nikolic
Keyword(s):  
Electrochemical Impedance ◽  
Sol Gel ◽  
Open Circuit ◽  
Stability Test ◽  
Electrochemical Characteristics ◽  
Potential Region ◽  
Metal Chlorides ◽  
Transmission Electron ◽  
Accelerated Stability ◽  
Activity Loss

The properties of activated titanium anodes, RuO2-TiO2/Ti and RuO2--TiO2-IrO2/Ti, prepared from oxide sols by the sol-gel procedure, are reviewed. RuO2 and TiO2 sols were synthesized by forced hydrolysis of the corresponding chlorides in acid medium. The morphology of the prepared sols was investigated by transmission electron microscopy. The chemical composition of the RuO2 sol was determined by X-ray diffraction and thermogravimetric analysis. The loss of electrocatalytic activity of a RuO2-TiO2/Ti anode during an accelerated stability test was investigated by examination of the changes in the electrochemical characteristics in the potential region of the chlorine and oxygen evolution reaction, as well as on the open circuit potential. These electrochemical characteristics were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and polarization measurements. The changes in electrochemical characteristics of the anode prepared by the sol-gel procedure were compared to the changes registered for an anode prepared by the traditional thermal decomposition of metal chlorides. The comparison indicated that the main cause for the activity loss of the sol-gel prepared anode was the electrochemical dissolution of RuO2, while in the case of thermally prepared anode the loss was mainly caused by the formation of an insulating TiO2 layer in the coating/Ti substrate interphase. The results of an accelerated stability test on RuO2-TiO2/Ti and RuO2--TiO2-IrO2/Ti anodes showed that the ternary coating is considerably more stable than the binary one, which is the consequence of the greater stability of IrO2 in comparison to RuO2.

scholarly journals Sol-gel prepared active ternary oxide coating on titanium in cathodic protection

2007 ◽  
Vol 72 (12) ◽  
pp. 1393-1402 ◽  
Author(s):  
Vladimir Panic ◽  
Branislav Nikolic
Keyword(s):  
Cathodic Protection ◽  
Sol Gel ◽  
Oxide Coating ◽  
Molar Ratio ◽  
Ternary Oxide ◽  
Electrochemical Characteristics ◽  
Accelerated Corrosion ◽  
Metal Chlorides ◽  
Corrosion Stability ◽  
The Stability

The characteristics of a ternary oxide coating, on titanium, which consisted of TiO2, RuO2 and IrO2 in the molar ratio 0.6:0.3:0.1, calculated on the metal atom, were investigated for potential application for cathodic protection in a seawater environment. The oxide coatings on titanium were prepared by the sol-gel procedure from a mixture of inorganic oxide sols, which were obtained by forced hydrolysis of metal chlorides. The morphology of the coating was examined by scanning electron microscopy. The electrochemical properties of activated titanium anodes were investigated by cyclic voltammetry and polarization measurements in a H2SO4- and NaCl-containing electrolyte, as well as in seawater sampled on the Adriatic coast in Tivat, Montenegro. The anode stability during operation in seawater was investigated by the galvanostatic accelerated corrosion stability test. The morphology and electrochemical characteristics of the ternary coating are compared to that of a sol-gel-prepared binary Ti0.6Ru0.4O2 coating. The activity of the ternary coating was similar to that of the binary Ti0.6Ru0.4O2 coating in the investigated solutions. However, the stability in seawater is found to be considerably greater for the ternary coating.

scholarly journals Electrochemical and Oxidation Behavior of Yttria Stabilized Zirconia Coating on Zircaloy-4 Synthesized via Sol-Gel Process

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
S. Rezaee ◽  
Gh. R. Rashed ◽  
M. A. Golozar
Keyword(s):  
Heat Treatment ◽  
Electrochemical Impedance ◽  
Sol Gel ◽  
Dip Coating ◽  
Open Circuit ◽  
Treatment Temperature ◽  
Yttria Stabilized Zirconia ◽  
Coated Sample ◽  
Stabilized Zirconia ◽  
Temperature Oxidation

Sol-gel 8 wt.% Yttria Stabilized Zirconia (YSZ) thin films were prepared on zirconium (zircaloy-4 alloy) by dip-coating technique followed by heat treating at various temperatures (200°C, 400°C, and 700°C) in order to improve both electrochemical corrosion and high temperature oxidation properties of the substrate. Differential thermal analysis and thermogravimetric analysis (DTA-TG) revealed the coating formation process. X-ray diffraction (XRD) was used to determine the crystalline phase structure transformation. The morphological characterization of the coatings was carried out using scanning electron microscopy (SEM). The electrochemical behavior of the coated and uncoated samples was investigated by means of open circuit potential, Tafel, and electrochemical impedance spectroscopy (EIS) in a 3.5 wt.% NaCl solution. The homogeneity and surface appearance of coatings produced was affected by the heat treatment temperature. According to the corrosion parameters, the YSZ coatings showed a considerable increase in the corrosion resistance, especially at higher heat treatment temperatures. The coating with the best quality, from the surface and corrosion point of view, was subjected to oxidation test in air at 800°C. The coated sample presented a 25% reduction in oxidation rate in comparison with bare substrate.

A comparative study of doped and un-doped sol-gel TiO2 and P25 TiO2 (photo)electrodes

2007 ◽  
Vol 55 (12) ◽  
pp. 153-160 ◽  
Author(s):  
Y. Pooarporn ◽  
A. Worayingyong ◽  
M. Wörner ◽  
P. Songsiriritthigul ◽  
A.M. Braun
Keyword(s):  
Indium Tin Oxide ◽  
Electrochemical Impedance ◽  
Anatase Phase ◽  
Sol Gel ◽  
Oxide Glass ◽  
Electrochemical Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Titanium Dioxide Films ◽  
Indium Tin Oxide Glass

Doped and undoped titanium dioxide films have been deposited on indium tin oxide glass using the sol-gel technique. The percentage of rutile in the prepared TiO2, calcined at 823 K and determined by X-ray diffraction, was 23% compared to 24% of rutile in P25-TiO2. Cerium doped TiO2 showed mainly the anatase phase, as characterised by both X-ray diffraction and Raman spectroscopy. The electrochemical and photoelectrochemical properties of the films were studied by cyclic voltammetry and electrochemical impedance spectroscopy. The (photo)electrochemical characteristics of the different films are reported and discussed.

Effect of nanomaterials in platinum-decorated carbon nanotube paste-based electrodes for amperometric glucose detection

2008 ◽  
Vol 23 (5) ◽  
pp. 1457-1465 ◽  
Author(s):  
Jining Xie ◽  
Shouyan Wang ◽  
L. Aryasomayajula ◽  
V.K. Varadan
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Electrochemical Impedance ◽  
Glucose Sensing ◽  
Electrochemical Characteristics ◽  
Current Response ◽  
X Ray Diffraction ◽  
Multiwalled Carbon ◽  
Transmission Electron ◽  
Wide Range

The effect of nanomaterials in platinum-decorated, multiwalled, carbon nanotube-based electrodes for amperometric glucose sensing was investigated by a comparative study with other carbon material-based electrodes such as graphite, glassy carbon, and multiwalled carbon nanotubes. Scanning and transmission electron microscopy and x-ray diffraction were used to investigate their morphologies and crystallinities. Electrochemical impedance spectroscopy was conducted to compare the electrochemical characteristics of these electrodes. The glucose-sensing results from the chronoamperometric measurements indicated that carbon nanotubes improve the linearity of the current response to glucose concentrations over a wide range, and that platinum decoration of the carbon nanotubes produces improved electrochemical performance with a higher sensitivity.

scholarly journals SiO2-GO nanofillers enhance the corrosion resistance of waterborne polyurethane acrylic coatings

2020 ◽  
Vol 29 ◽  
pp. 2633366X2094152
Author(s):  
Liqi Liu ◽  
Xiaofeng Guo ◽  
Lei Shi ◽  
Liquan Chen ◽  
Fangzhou Zhang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Electron Microscope ◽  
Electrochemical Impedance ◽  
Sol Gel ◽  
Waterborne Polyurethane ◽  
Metal Corrosion ◽  
X Ray Diffraction ◽  
Functionalized Graphene Oxide ◽  
Transmission Electron ◽  
Acrylic Coatings

Corrosion to metal is a great challenge to major industries. Anticorrosive coatings can effectively prevent metal corrosion. In this study, we propose a novel method to prepare silica nanoparticles-covered graphene oxide (SiO2-GO) nanohybrids and anticorrosion SiO2-GO/waterborne polyurethane acrylic (WPUA) coatings. Firstly, we obtained silane-functionalized graphene oxide (A-GO) via a simple covalent functionalization of graphene oxide (GO) with 3-aminopropyltriethoxysilane. Secondly, SiO2-GO was synthesized by a simple sol–gel method with tetraethoxysilane in water–alcohol solution. Finally, the obtained SiO2-GO nanofillers were added into WPUA to prepare SiO2-GO/WPUA coatings. GO, A-GO, and SiO2-GO nanohybrids could be confirmed by X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectra, and transmission electron microscope. SiO2-GO nanohybrids showed small size compared with the unfunctionalized GO. Meanwhile, GO, A-GO, and SiO2-GO nanofillers were added into WPUA. The electrochemical impedance spectroscopy and field emission scanning electron microscope indicate that SiO2-GO nanohybrids can be homogeneously dispersed in the WPUA coatings at 0.4% loading level and the SiO2-GO/WPUA film exhibits excellent anticorrosion performance. SiO2-GO nanoparticles can effectively utilize in the area of anticorrosive nanofiller industry. This study provides a convenient method of anticorrosive coating production.

Electrochemical Determination of the Corrosion Resistance of Ag-Pd Dental Alloys

2008 ◽  
Vol 59 (9) ◽  
Author(s):  
Daniel Mareci ◽  
Igor Cretescu ◽  
Neculai Aelenei ◽  
Julia Claudia Mirza Rosca
Keyword(s):  
Corrosion Resistance ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Artificial Saliva ◽  
Surface Film ◽  
Electrochemical Determination ◽  
Open Circuit ◽  
Electrochemical Characteristics

The electrochemical behavior of a three Ag-Pd alloys used in dental prosthetics construction for crowns and bridges was studied in artificial saliva using the polarization curves and electrochemical impedance spectroscopy (EIS). The corrosion resistance was evaluated by means of the corrosion currents value and by coulometric analysis. The open circuit potential of Ag-Pd are attributed to dealloying followed by surface enrichment with Ag and the possible formation of an insoluble AgCl surface film on the respective alloy surfaces. Our results have shown that these alloys have a somewhat good corrosion resistance in artificial saliva. When increasing the content of Cu, corrosion resistance decreases. The passivation of all samples occurred spontaneously at the open circuit potential. The electrochemical properties of the spontaneously passivated electrodes at the open circuit potential were studied by EIS. The polarization resistance (Rp) and the electrode capacitance (Cdl) were determined. The polarisation resistance of all the samples increases with the immersion time. The polarization resistances are largest and decrease when increasing the content of Cu. Cu reduces the Ag-Pd alloy corrosion resistance. The present study, thought limited, has shown that electrochemical characteristics can be use to identify such alloys. Knowledge of the in vitro corrosion behaviour of these alloys may lead to better understanding of any biologically adverse effects in vitro.

scholarly journals Characterization of Oxide Film of Implantable Metals by Electrochemical Impedance Spectroscopy

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3466 ◽  
Author(s):  
Okazaki
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Oxide Film ◽  
Electrochemical Impedance ◽  
Saturated Calomel Electrode ◽  
Oxide Films ◽  
Relative Dielectric Constant ◽  
Open Circuit ◽  
Thin Oxide Film ◽  
Transmission Electron

The oxide film resistance (RP) and capacitance (CCPE) diagrams of implantable metals (commercially pure Ti, four types of Ti alloys, Co–28Cr–6Mo alloy, and stainless steel) were investigated by electrochemical impedance spectroscopy (EIS). The thin oxide film formed on each implantable metal surface was observed in situ by field-emission transmission electron microscopy (FE-TEM). The Ti–15Zr–4Nb–1Ta and Ti–15Zr–4Nb–4Ta alloys had higher oxygen concentrations in the oxide films than the Ti–6Al–4V alloy. The thickness (d) of the TiO2 oxide films increased from approximately 3.5 to 7 nm with increasing anodic polarization potential from the open-circuit potential to a maximum of 0.5 V vs. a saturated calomel electrode (SCE) in 0.9% NaCl and Eagle’s minimum essential medium. RP for the Ti–15Zr–4Nb–1Ta and Ti–15Zr–4Nb–4Ta alloys was proportional to d obtained by FE-TEM. CCPE was proportional to 1/d. RP tended to decrease with increasing CCPE. RP was large (maximum: 13 MΩ·cm2) and CCPE was small (minimum: 12 μF·cm−2·sn−1, n = 0.94) for the Ti–15Zr–4Nb–(0 to 4)Ta alloys. The relative dielectric constant (εr) and resistivity (kOX) of the oxide films formed on these alloys were 136 and 2.4 × 106–1.8 × 107 (MΩ·cm), respectively. The Ta-free Ti–15Zr–4Nb alloy is expected to be employed as an implantable material for long-term use.

Dye-Sensitized Solar Cells Based on Novel Mixed Dyes

2011 ◽  
Vol 383-390 ◽  
pp. 5510-5515
Author(s):  
Tien Tsan Hung
Keyword(s):  
Solar Cells ◽  
Electrochemical Impedance ◽  
Short Circuit ◽  
Sol Gel ◽  
Dye Sensitized Solar Cells ◽  
Open Circuit ◽  
Membrane Electrode ◽  
Dye Sensitized ◽  
Phthalocyanine Derivative ◽  
Sensitized Solar Cells

Novel phthalocyanine derivative and azo derivative have been synthesized as photosensitizers for the dye-sensitized solar cells (DSSCs). We used sol-gel method to prepare the titanium oxide (TiO2) membrane electrode of the DSSCs. The crystalline phase and surface morphology of TiO2 were characterized by using X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM) to investigate the effects of processing parameters on the films characteristic, microstructure and thickness. The performance of DSSCs was characterized by using electrochemical impedance spectroscopy (EIS) and current-voltage curve analysis. The sensitizing properties of phthalocyanine derivative, azo derivative and mixed dyes were studied, and it was found that the cell consisted of mixed dyes generated the highest power conversion efficiency () of 2.3 %, short circuit photocurrent density (Jsc) of 13.6 mA cm-2, open circuit photovoltage (Voc) of 0.46 V and fill factor (FF) of 0.37 under simulated AM 1.5 irradiation (100 mW cm-2) with a active area of 0.25 cm2.

scholarly journals Differences in the electrochemical behavior of ruthenium and iridium oxide in electrocatalytic coatings of activated titanium anodes prepared by the sol-gel procedure

2010 ◽  
Vol 75 (10) ◽  
pp. 1413-1420 ◽  
Author(s):  
Vladimir Panic ◽  
Aleksandar Dekanski ◽  
Vesna Miskovic-Stankovic ◽  
Slobodan Milonjic ◽  
Branislav Nikolic
Keyword(s):  
Sol Gel ◽  
Potential Range ◽  
Electrochemical Characteristics ◽  
H2so4 Solution ◽  
Metal Chlorides ◽  
Impedance Characteristics ◽  
Voltammetric Behavior ◽  
Redox Transitions ◽  
Surface Redox ◽  
Hydrolysis Of

The electrochemical characteristics of Ti0.6Ir0.4O2/Ti and Ti0.6Ru0.4O2/Ti anodes prepared by the sol-gel procedure from the corresponding oxide sols, obtained by force hydrolysis of the corresponding metal chlorides, were compared. The voltammetric properties in H2SO4 solution indicate that Ti0.6Ir0.4O2/Ti has more pronounced pseudocapacitive characteristics, caused by proton-assisted, solid state surface redox transitions of the oxide. At potentials negative to 0.0 VSCE, this electrode is of poor conductivity and activity, while the voltammetric behavior of the Ti0.6Ru0.4O2/Ti electrode is governed by proton injection/ejection into the oxide structure. The Ti0.6Ir0.4O2/Ti electrode had a higher electrocatalytical activity for oxygen evolution, while the investigated anodes were of similar activity for chlorine evolution. The potential dependence of the impedance characteristics showed that the Ti0.6Ru0.4O2/Ti electrode behaved like a capacitor over a wider potential range than the Ti0.6Ir0.4O2/Ti electrode, with fully-developed pseudocapacitive properties at potentials positive to 0.60 VSCE. However, the impedance characteristics of the Ti0.6Ir0.4O2/Ti electrode changed with increasing potential from resistor-like to capacitor-like behavior.

Anatase TiO2 Films via a Sol-Gel and Hydrothermal Crystallization for Enhanced Corrosion Resistance

2011 ◽  
Vol 356-360 ◽  
pp. 2707-2710 ◽  
Author(s):  
Hong Yun ◽  
Chang Jian Lin ◽  
Qun Jie Xu
Keyword(s):  
Corrosion Resistance ◽  
Hydrothermal Treatment ◽  
316L Stainless Steel ◽  
Electrochemical Impedance ◽  
Sol Gel ◽  
Metallic Substrates ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Sol Gel Process

Anatase of TiO2films were supplied on the surface of 316L stainless steel by a sol–gel process followed by hydrothermal treatment in water. The as-prepared samples were characterized with filed emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), atomic force microscopy (AFM) and Raman spectroscopy. The corrosion performances of the films in 3.5 wt% NaCl solution were evaluated by electrochemical impedance spectroscopy (EIS) and polarization measurements. The results revealed that the corrosion resistance of the TiO2films via the hydrothermal treatment at 170°C for 4h exceeded that of the counterparts treated by conventional calcination at 450°C. This could be attributed that the surface of such a sample was more compact and uniform, relatively well-crystallized, able to act as an optimal barrier layer to metallic substrates.

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