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Sample records for plasma electrolytic oxidation

  1. Plasma electrolytic oxidation of metals

    Directory of Open Access Journals (Sweden)

    Stojadinović Stevan

    2013-01-01

    Full Text Available In this lecture results of the investigation of plasma electrolytic oxidation (PEO process on some metals (aluminum, titanium, tantalum, magnesium, and zirconium were presented. Whole process involves anodizing metals above the dielectric breakdown voltage where numerous micro-discharges are generated continuously over the coating surface. For the characterization of PEO process optical emission spectroscopy and real-time imaging were used. These investigations enabled the determination of electron temperature, electron number density, spatial density of micro-discharges, the active surface covered by micro-discharges, and dimensional distribution of micro-discharges at various stages of PEO process. Special attention was focused on the results of the study of the morphology, chemical, and phase composition of oxide layers obtained by PEO process on aluminum, tantalum, and titanium in electrolytes containing tungsten. Physicochemical methodes: atomic force microscopy (AFM, scanning electron microscopy (SEM-EDS, x-ray diffraction (XRD, x-ray photoelectron spectroscopy (XPS, and Raman spectroscopy served as tools for examining obtained oxide coatings. Also, the application of the obtained oxide coatings, especially the application of TiO2/WO3 coatings in photocatalysis, were discussed.

  2. Plasma electrolytic oxidation of AMCs

    Science.gov (United States)

    Morgenstern, R.; Sieber, M.; Lampke, T.

    2016-03-01

    Aluminum Matrix Composites (AMCs) consisting of high-strength alloys and ceramic reinforcement phases exhibit a high potential for security relevant lightweight components due to their high specific mechanical properties. However, their application as tribologically stressed components is limited because of their susceptibility against fatigue wear and delamination wear. Oxide ceramic protective coatings produced by plasma electrolytic oxidation (PEO) can solve these problems and extend the possible applications of AMCs. The substrate material was powder metallurgically processed using alloy EN AW 2017 and SiC or Al2O3 particles. The influence of material properties like particle type, size and volume fraction on coating characteristics is clarified within this work. An alkaline silicate electrolyte was used to produce PEO coatings with technically relevant thicknesses under bipolar-pulsed current conditions. Coating properties were evaluated with regard to morphology, chemical composition, hardness and wear resistance. The particle type proved to have the most significant effect on the coating properties. Whereas compactness and thickness are not deteriorated by the incorporation of thermodynamically stable alumina particles, the decomposition of silica particles during the PEO processes causes an increase of the porosity. The higher silica particle content decreases also the coating thickness and hardness, which leads in particular to reduction of the wear resistance of the PEO coatings. Finally, different approaches for the reduction of the coating porosity of silica reinforced AMCs are discussed.

  3. Plasma electrolytic oxidation of Titanium Aluminides

    International Nuclear Information System (INIS)

    Morgenstern, R; Sieber, M; Lampke, T; Grund, T; Wielage, B

    2016-01-01

    Due to their outstanding specific mechanical and high-temperature properties, titanium aluminides exhibit a high potential for lightweight components exposed to high temperatures. However, their application is limited through their low wear resistance and the increasing high-temperature oxidation starting from about 750 °C. By the use of oxide ceramic coatings, these constraints can be set aside and the possible applications of titanium aluminides can be extended. The plasma electrolytic oxidation (PEO) represents a process for the generation of oxide ceramic conversion coatings with high thickness. The current work aims at the clarification of different electrolyte components’ influences on the oxide layer evolution on alloy TNM-B1 (Ti43.5Al4Nb1Mo0.1B) and the creation of compact and wear resistant coatings. Model experiments were applied using a ramp-wise increase of the anodic potential in order to show the influence of electrolyte components on the discharge initiation and the early stage of the oxide layer growth. The production of PEO layers with technically relevant thicknesses close to 100 μm was conducted in alkaline electrolytes with varying amounts of Na 2 SiO 3 ·5H 2 O and K 4 P 2 O 7 under symmetrically pulsed current conditions. Coating properties were evaluated with regard to morphology, chemical composition, hardness and wear resistance. The addition of phosphates and silicates leads to an increasing substrate passivation and the growth of compact oxide layers with higher thicknesses. Optimal electrolyte compositions for maximum coating hardness and thickness were identified by statistical analysis. Under these conditions, a homogeneous inner layer with low porosity can be achieved. The frictional wear behavior of the compact coating layer is superior to a hard anodized layer on aluminum. (paper)

  4. Plasma electrolytic oxide coatings on silumin for oxidation CO

    Science.gov (United States)

    Borisov, V. A.; Sigaeva, S. S.; Anoshkina, E. A.; Ivanov, A. L.; Litvinov, P. V.; Vedruchenko, V. R.; Temerev, V. L.; Arbuzov, A. B.; Kuznetsov, A. A.; Mukhin, V. A.; Suprunov, G. I.; Chumychko, I. A.; Shlyapin, D. A.; Tsyrul'nikov, P. G.

    2017-08-01

    Some catalysts of CO oxidation on silumin alloy AK12M2, used for the manufacture of pistons for Russian cars were investigated. The catalysts were prepared by the method of plasma electrolytic oxidation of silumin in electrolytes of various compositions with further activation by the salts Ce, Cu, Co, Ni, Mn and Al. The catalytic tests were carried out in a flow reactor in a mixture of 1% CO and 99% air, with the temperature range of 25-500 °C. The most active catalysts in CO oxidation are those activated with Ce and Cu salts on silumin, treated for 3 hours in an electrolyte containing 4 g/l KOH, 40 g/l Na2B4O7 (conversion of CO is 93.7% at a contact time of 0.25 s). However, the catalysts obtained from silumin treated in the electrolyte containing 3 g/l KOH, 30 g/l Na2SiO3 are more suitable for practical usage. Because when the treatment time of those catalysts is 10 - 20 minutes it is possible to achieve comparable CO conversion. The morphology and composition of the catalysts were studied by the methods of a scanning electron microscope with energy-dispersive surface analysis and X-ray phase analysis. The surface of the non-activated sample consists of γ-Al2O3 and SiO2 particles, due to which the active components get attached to the support. CeO2 and CuO are present on the surface of the sample with the active component.

  5. Study of Plasma Electrolytic Oxidation Coatings on Aluminum Composites

    Directory of Open Access Journals (Sweden)

    Leonid Agureev

    2018-06-01

    Full Text Available Coatings, with a thickness of up to 75 µm, were formed by plasma electrolytic oxidation (PEO under the alternating current electrical mode in a silicate-alkaline electrolyte on aluminum composites without additives and alloyed with copper (1–4.5%. The coatings’ structure was analyzed by scanning electron microscopy, X-ray microanalysis, X-ray photoelectron spectroscopy, nuclear backscattering spectrometry, and XRD analysis. The coatings formed for 60 min were characterized by excessive aluminum content and the presence of low-temperature modifications of alumina γ-Al2O3 and η-Al2O3. The coatings formed for 180 min additionally contained high-temperature corundum α-Al2O3, and aluminum inclusions were absent. The electrochemical behavior of coated composites and uncoated ones in 3% NaCl was studied. Alloyage of aluminum composites with copper increased the corrosion current density. Plasma electrolytic oxidation reduced it several times.

  6. Effect upon biocompatibility and biocorrosion properties of plasma electrolytic oxidation in trisodium phosphate electrolytes.

    Science.gov (United States)

    Kim, Yu-Kyoung; Park, Il-Song; Lee, Kwang-Bok; Bae, Tae-Sung; Jang, Yong-Seok; Oh, Young-Min; Lee, Min-Ho

    2016-03-01

    Surface modification to improve the corrosion resistance and biocompatibility of the Mg-Al-Zn-Ca alloy was conducted via plasma electrolytic oxidation (PEO) in an electrolyte that included phosphate. Calcium phosphate can be easily induced on the surface of a PEO coating that includes phosphate in a physiological environment because Ca(2+) ions in body fluids can be combined with PO4 (3-). Cytotoxicity of the PEO coating formed in electrolytes with various amounts of Na3PO4 was identified. In particular, the effects that PEO films have upon oxidative stress and differentiation of osteoblast activity were studied. As the concentration of Na3PO4 in the electrolyte increased, the oxide layer was found to become thicker, which increased corrosion resistance. However, the PEO coating formed in electrolytes with over 0.2 M of added Na3PO4 exhibited more microcracks and larger pores than those formed in smaller Na3PO4 concentrations owing to a large spark discharge. A nonuniform oxide film that included more phosphate caused more cytotoxicity and oxidative stress, and overabundant phosphate content in the oxide layer interrupted the differentiation of osteoblasts. The corrosion resistance of the magnesium alloy and the thickness of the oxide layer were increased by the addition of Na3PO4 in the electrolyte for PEO treatment. However, excessive phosphate content in the oxide layer led to oxidative stress, which resulted in reduced cell viability and activity.

  7. Composition of highly concentrated silicate electrolytes and ultrasound influencing the plasma electrolytic oxidation of magnesium

    Science.gov (United States)

    Simchen, F.; Rymer, L.-M.; Sieber, M.; Lampke, T.

    2017-03-01

    Magnesium and its alloys are increasingly in use as lightweight construction materials. However, their inappropriate corrosion and wear resistance often prevent their direct practical use. The plasma electrolytic oxidation (PEO) is a promising, environmentally friendly method to improve the surface characteristics of magnesium materials by the formation of oxide coatings. These PEO layers contain components of the applied electrolyte and can be shifted in their composition by increasing the concentration of the electrolyte constituents. Therefore, in contrast to the use of conventional low concentrated electrolytes, the process results in more stable protective coatings, in which electrolyte species are the dominating constitutes. In the present work, the influence of the composition of highly concentrated alkaline silicate electrolytes with additives of phosphate and glycerol on the quality of PEO layers on the magnesium alloy AZ31 was examined. The effect of ultrasound coupled into the electrolyte bath was also considered. The process was monitored by recording the electrical process variables with a transient recorder and by observation of the discharge phenomena on the sample surface with a camera. The study was conducted on the basis of a design of experiments. The effects of the process parameter variation are considered with regard to the coatings thickness, hardness and corrosion resistance. Information about the statistical significance of the effects of the parameters on the considered properties is obtained by an analysis of variance (ANOVA).

  8. Designing advanced materials by environmental friendly plasma electrolytic oxidation

    International Nuclear Information System (INIS)

    Toader, I.; Valeca, M.; Rusu, O.; Coaca, E.; Marin, A.

    2016-01-01

    In the CANDU-PHWR nuclear reactors, Zr-2.5Nb coated with a black adherent oxide film of 1 to 2 μm in thickness is currently used for the manufacture of pressure tubes. The black oxide thin film has corrosion protective properties. However, it can be damaged during the regular refueling process, thus causing hydrogen/oxygen ingression. Therefore, an enhanced wear and corrosion resistance coating is needed. Plasma electrolytic oxidation (PEO) is an anodic electrochemical treatment, both cost-effective and environmentally friendly, widely used in the formation of a protective oxide film on the metal surface to enhance wear and corrosion resistance as well as prolonging component lifetime. The state of the art reveals that PEO method is suitable for improving the wear resistance of Zr-2.5Nb alloy. Few studies are performed in this field and thus, it is necessary to conduct a more detailed insight study on the processing parameters for PEO treatment. By understanding the influence of process parameters, such as electrolyte temperature and electrolyte composition, we can find the way to obtain a coating with improved mechanical and corrosion properties on zirconium alloys. (authors)

  9. AC plasma electrolytic oxidation of magnesium with zirconia nanoparticles

    International Nuclear Information System (INIS)

    Arrabal, R.; Matykina, E.; Viejo, F.; Skeldon, P.; Thompson, G.E.; Merino, M.C.

    2008-01-01

    The incorporation of monoclinic zirconia nanoparticles and their subsequent transformation is examined for coatings formed on magnesium by plasma electrolytic oxidation under AC conditions in silicate electrolyte. The coatings are shown to comprise two main layers, with nanoparticles entering the coating at the coating surface and through short-circuit paths to the region of the interface between the inner and outer coating layers. Under local heating of microdischarges, the zirconia reacts with magnesium species to form Mg 2 Zr 5 O 12 in the outer coating layer. Relatively little zirconium is present in the inner coating layer. In contrast, silicon species are present in both coating layers, with reduced amounts in the inner layer

  10. Discharge behaviors during plasma electrolytic oxidation on aluminum alloy

    International Nuclear Information System (INIS)

    Liu, Run; Wu, Jie; Xue, Wenbin; Qu, Yao; Yang, Chaolin; Wang, Bin; Wu, Xianying

    2014-01-01

    A plasma electrolytic oxidation (PEO) process was performed on the 2024 aluminum alloy in silicate electrolyte to fabricate ceramic coatings under a constant voltage. Optical emission spectroscopy (OES) was employed to evaluate the characteristics of plasma discharge during PEO process. The plasma electron temperature and density were obtained by analyzing the spectral lines of OES, and the atomic ionization degree in discharge zone was calculated in terms of Saha thermal ionization equation. The illumination intensity of plasma discharge and the temperature in the interior of alloy were measured. Combining the surface morphology and cross-sectional microstructure with the optical emission spectra and illumination at different discharge stage, a discharge model in the growth of PEO ceramic coatings was proposed. It is found that there are two discharge modes of type A with small spark size and type B with large spark size, and the latter only appears in the intermediate stage of PEO process. The illumination intensity has a maximum value in the initial stage of oxidation with many sparks of discharge type A. The electron temperature in plasma discharge zone is about 3000 K–7000 K and atomic ionization degree of Al is about 2.0 × 10 −5 –7.2 × 10 −3 , which depend on discharge stage. The discharge type B plays a key role on the electron temperature and atomic ionization degree. The electron density keeps stable in the range of about 8.5 × 10 21  m −3 –2.6 × 10 22  m −3 . - Highlights: • The characteristics of PEO plasma discharge was evaluated by OES. • Electron temperature, concentration, atomic ionization degree were calculated. • Discharge model for the growth of PEO coatings was proposed. • Temperature in the interior of alloy during PEO process was measured

  11. Effects of electrolytes variation on formation of oxide layers of 6061 Al alloys by plasma electrolytic oxidation

    Institute of Scientific and Technical Information of China (English)

    Kai WANG; Bon-Heun KOO; Chan-Gyu LEE; Young-Joo KIM; Sung-Hun LEE; Eungsun BYON

    2009-01-01

    Plasma electrolytic oxidation(PEO) processes were carried out to produce ceramic layers on 6061 aluminum substrates in four kinds of electrolytes such as silicate and aluminate solution with and without sodium fluorosilicate. The PEO processes were carried out under a hybrid voltage (260 V DC combined with 200 V, 60 Hz AC amplitude) at room temperature for 5 min. The composition, microstructure and element distribution analyses of the PEO-treated layers were carried out by XRD and SEM & EDS. The effect of the electrolyte contents on the growth mechanism, element distribution and properties of oxide layers were studied. It is obvious that the layers generated in aluminate solutions show smoother surfaces than those in silicate solutions. Moreover, an addition of fluorine ion can effectively control the layer porosity; therefore, it can enhance the properties of the layers.

  12. Corrosion evaluation of zirconium doped oxide coatings on aluminum formed by plasma electrolytic oxidation.

    Science.gov (United States)

    Bajat, Jelena; Mišković-Stanković, Vesna; Vasilić, Rastko; Stojadinović, Stevan

    2014-01-01

    The plasma electrolytic oxidation (PEO) of aluminum in sodium tungstate (Na(2)WO(4) · (2)H(2)O) and Na(2)WO(4) · (2)H(2)O doped with Zr was analyzed in order to obtain oxide coatings with improved corrosion resistance. The influence of current density in PEO process and anodization time was investigated, as well as the influence of Zr, with the aim to find out how they affect the chemical content, morphology, surface roughness, and corrosion stability of oxide coatings. It was shown that the presence of Zr increases the corrosion stability of oxide coatings for all investigated PEO times. Evolution of EIS spectra during the exposure to 3% NaCl, as a strong corrosive agent, indicated the highest corrosion stability for PEO coating formed on aluminum at 70 mA/cm(2) for 2 min in a zirconium containing electrolyte.

  13. Preparation and corrosion resistance of a nanocomposite plasma electrolytic oxidation coating on Mg-1%Ca alloy formed in aluminate electrolyte containing titania nano-additives

    DEFF Research Database (Denmark)

    Daroonparvar, Mohammadreza; Yajid, M. A. M.; Yusof, N. M.

    2016-01-01

    Titania nanoparticles were utilized as suspension in alkaline aluminate electrolyte to form nanocomposite coatings on magnesium alloy containing 1 wt% calcium by plasma electrolytic oxidation process. Microhardness, wettability, potentiodynamic polarization, wettability, electrochemical impedance...

  14. Electrochemical corrosion behaviour of plasma electrolytic oxidation coatings on AM50 magnesium alloy formed in silicate and phosphate based electrolytes

    International Nuclear Information System (INIS)

    Liang, J.; Srinivasan, P. Bala; Blawert, C.; Stoermer, M.; Dietzel, W.

    2009-01-01

    PEO coatings were produced on AM50 magnesium alloy by plasma electrolytic oxidation process in silicate and phosphate based electrolytes using a pulsed DC power source. The microstructure and composition of the PEO coatings were analyzed by scanning electron microscopy (SEM) and X-ray Diffraction (XRD). The corrosion resistance of the PEO coatings was evaluated using open circuit potential (OCP) measurements, potentiodynamic polarisation tests and electrochemical impedance spectroscopy (EIS) in 0.1 M NaCl solution. It was found that the electrolyte composition has a significant effect on the coating evolution and on the resulting coating characteristics, such as microstructure, composition, coating thickness, roughness and thus on the corrosion behaviour. The corrosion resistance of the PEO coating formed in silicate electrolyte was found to be superior to that formed in phosphate electrolyte in both the short-term and long-term electrochemical corrosion tests.

  15. Plasma electrolytic oxidation of titanium in a phosphate/silicate electrolyte and tribological performance of the coatings

    Energy Technology Data Exchange (ETDEWEB)

    Aliasghari, S.; Skeldon, P., E-mail: p.skeldon@manchester.ac.uk; Thompson, G.E.

    2014-10-15

    Highlights: • Plasma electrolytic oxidation performed of titanium in silicate/phosphate electrolyte. • Range of duty cycle, current density, positive-to-negative current ratio studied. • Coatings contain anatase, rutile, Ti{sub 3}O{sub 5}, and amorphous silica. • Ptfe incorporated into coatings by addition of ptfe emulsion to the electrolyte. • Fiction reduced but wear life relatively short due to porosity of coatings. - Abstract: Plasma electrolytic oxidation of titanium has been investigated using a phosphate/silicate electrolyte with a square waveform and a frequency of 50 Hz. A range of constant rms current densities, duty cycles and negative-to-positive current ratios was employed. The resultant coatings were examined by analytical scanning and transmission electron microscopies and X-ray diffraction. The coatings, which were limited in thickness to ∼40 to 50 μm, contained anatase, rutile, Ti{sub 2}O{sub 5} and silicon-rich, amorphous material. The tribological behaviour was investigated using a ball-on-disc test, revealing a coefficient of friction against steel of ∼0.8, which reduced to ∼0.4 by incorporation of ptfe particles from the electrolyte. However, due to the composition and morphology of the coatings, their wear life was relatively short.

  16. Plasma electrolytic oxidation of titanium in a phosphate/silicate electrolyte and tribological performance of the coatings

    International Nuclear Information System (INIS)

    Aliasghari, S.; Skeldon, P.; Thompson, G.E.

    2014-01-01

    Highlights: • Plasma electrolytic oxidation performed of titanium in silicate/phosphate electrolyte. • Range of duty cycle, current density, positive-to-negative current ratio studied. • Coatings contain anatase, rutile, Ti 3 O 5 , and amorphous silica. • Ptfe incorporated into coatings by addition of ptfe emulsion to the electrolyte. • Fiction reduced but wear life relatively short due to porosity of coatings. - Abstract: Plasma electrolytic oxidation of titanium has been investigated using a phosphate/silicate electrolyte with a square waveform and a frequency of 50 Hz. A range of constant rms current densities, duty cycles and negative-to-positive current ratios was employed. The resultant coatings were examined by analytical scanning and transmission electron microscopies and X-ray diffraction. The coatings, which were limited in thickness to ∼40 to 50 μm, contained anatase, rutile, Ti 2 O 5 and silicon-rich, amorphous material. The tribological behaviour was investigated using a ball-on-disc test, revealing a coefficient of friction against steel of ∼0.8, which reduced to ∼0.4 by incorporation of ptfe particles from the electrolyte. However, due to the composition and morphology of the coatings, their wear life was relatively short

  17. In situ formation of low friction ceramic coatings on carbon steel by plasma electrolytic oxidation in two types of electrolytes

    International Nuclear Information System (INIS)

    Wang Yunlong; Jiang Zhaohua

    2009-01-01

    In situ formation of ceramic coatings on Q235 carbon steel was achieved by plasma electrolytic oxidation (PEO) in carbonate electrolyte and silicate electrolyte, respectively. The surface and cross-section morphology, phase and elemental composition of PEO coatings were examined by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS). The bond strength of the coating was determined using a direct pull-off test. The hardness as well as tribological properties of the ceramic coating was primarily studied. The results indicated that the coating obtained in carbonate electrolyte was Fe 3 O 4 , while the coating achieved from silicate electrolyte was proved to be amorphous. Both kinds of coatings showed coarse and porous surface. The Fe 3 O 4 coatings obtained in carbonate electrolyte showed a high bonding strength to the substrate up to 20 ± 2 MPa and the value was 15 ± 2 MPa for the amorphous coatings obtained in carbonate electrolyte. The micro hardness of the amorphous coating and the Fe 3 O 4 coating was 1001 Hv and 1413 Hv, respectively, which was more than two and three times as that of the Q235 alloy substrate (415 Hv). The friction coefficient exhibited by amorphous coating and Fe 3 O 4 coating was 0.13 and 0.11, respectively, both lower than the uncoated Q235 substrate which ranged from 0.17 to 0.35.

  18. Electrochemical testing of suspension plasma sprayed solid oxide fuel cell electrolytes

    Science.gov (United States)

    Waldbillig, D.; Kesler, O.

    Electrochemical performance of metal-supported plasma sprayed (PS) solid oxide fuel cells (SOFCs) was tested for three nominal electrolyte thicknesses and three electrolyte fabrication conditions to determine the effects of electrolyte thickness and microstructure on open circuit voltage (OCV) and series resistance (R s). The measured OCV values were approximately 90% of the Nernst voltages, and electrolyte area specific resistances below 0.1 Ω cm 2 were obtained at 750 °C for electrolyte thicknesses below 20 μm. Least-squares fitting was used to estimate the contributions to R s of the YSZ bulk material, its microstructure, and the contact resistance between the current collectors and the cells. It was found that the 96% dense electrolyte layers produced from high plasma gas flow rate conditions had the lowest permeation rates, the highest OCV values, and the smallest electrolyte-related voltage losses. Optimal electrolyte thicknesses were determined for each electrolyte microstructure that would result in the lowest combination of OCV loss and voltage loss due to series resistance for operating voltages of 0.8 V and 0.7 V.

  19. Formation of a Spinel Coating on AZ31 Magnesium Alloy by Plasma Electrolytic Oxidation

    Science.gov (United States)

    Sieber, Maximilian; Simchen, Frank; Scharf, Ingolf; Lampke, Thomas

    2016-03-01

    Plasma electrolytic oxidation (PEO) is a common means for the surface modification of light metals. However, PEO of magnesium substrates in dilute electrolytes generally leads to the formation of coatings consisting of unfavorable MgO magnesium oxide. By incorporation of electrolyte components, the phase constitution of the oxide coatings can be modified. Coatings consisting exclusively of MgAl2O4 magnesium-aluminum spinel are produced by PEO in an electrolyte containing hydroxide, aluminate, and phosphate anions. The hardness of the coatings is 3.5 GPa on Martens scale on average. Compared to the bare substrate, the coatings reduce the corrosion current density in dilute sodium chloride solution by approx. one order of magnitude and slightly shift the corrosion potential toward more noble values.

  20. Effects of CH3OH Addition on Plasma Electrolytic Oxidation of AZ31 Magnesium Alloys

    Science.gov (United States)

    He, Yongyi; Chen, Li; Yan, Zongcheng; Zhang, Yalei

    2015-09-01

    Plasma electrolytic oxidation (PEO) films on AZ31 magnesium alloys were prepared in alkaline silicate electrolytes (base electrolyte) with the addition of different volume concentrations of CH3OH, which was used to adjust the thickness of the vapor sheath. The compositions, morphologies, and thicknesses of ceramic layers formed with different CH3OH concentrations were determined via X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), and scanning electron microscopy (SEM). Corrosion behavior of the oxide films was evaluated in 3.5 wt.% NaCl solution using potentiodynamic polarization tests. PEO coatings mainly comprised Mg, MgO, and Mg2SiO4. The addition of CH3OH in base electrolytes affected the thickness, pores diameter, and Mg2SiO4 content in the films. The films formed in the electrolyte containing 12% CH3OH exhibited the highest thickness. The coatings formed in the electrolyte containing different concentrations of CH3OH exhibited similar corrosion resistance. The energy consumption of PEO markedly decreased upon the addition of CH3OH to the electrolytes. The result is helpful for energy saving in the PEO process. supported by National Natural Science Foundation of China (No. 21376088), the Project of Production, Education and Research, Guangdong Province and Ministry of Education (Nos. 2012B09100063, 2012A090300015), and Guangzhou Science and Technology Plan Projects of China (No. 2014Y2-00042)

  1. Factors Influencing Plasma Electrolytic Oxidation(PEO) Coatings on Magnesium Alloys: A Review

    Energy Technology Data Exchange (ETDEWEB)

    Shim, Gunchoo [KISTI ReSEAT Program, Daejon (Korea, Republic of)

    2017-05-15

    Magnesium alloys, which possess excellent specific strength and castability, are highly susceptible to corrosion. Although anodizing is widely used to resolve this problem, it requires toxic electrolytes and produces relatively thin and weak surface coatings. Recently, plasma electrolytic oxidation (PEO) has emerged as an alternative to anodizing. Although it is derived from conventional anodizing, it uses eco-friendly electrolytes and forms thicker, denser, and harder coatings on the surface of magnesium alloys. However, PEO is a complex process involving physical, chemical, and electrochemical reactions, and it is influenced by various factors such as the alloy substrate composition, electrolyte/additive composition, and the electrical variables including the mode of power supply, applied voltage/current density, frequency, and duty cycle. In this article, the detailed effects of these parameters on the microstructure and properties of the PEO coatings are reviewed, and methods of improving the coatings are proposed.

  2. A general strategy toward the rational synthesis of metal tungstate nanostructures using plasma electrolytic oxidation method

    International Nuclear Information System (INIS)

    Jiang, Yanan; Liu, Baodan; Zhai, Zhaofeng; Liu, Xiaoyuan; Yang, Bing; Liu, Lusheng; Jiang, Xin

    2015-01-01

    Graphical abstract: A general strategy for the rational synthesis of tungstate nanostructure has been developed based on plasma electrolytic oxidation (PEO) technology (up). Using this method, ZnWO 4 and NiWO 4 nanostructures with controllable morphologies and superior crystallinity can be easily obtained (down), showing obvious advantage in comparison with conventional hydrothermal and sol–gel methods. - Highlights: • Plasma electrolyte oxidation (PEO) method has been used for the rational synthesis of tungstate nanostructures. • ZnWO 4 nanoplates have strong mechanical adhesion with porous TiO 2 film substrate. • The morphology and dimensional size of ZnWO 4 nanostructures can be selectively tailored by controlling the annealing temperature and growth time. • The PEO method can be widely applied to the growth of various metal oxides. - Abstract: A new method based on conventional plasma electrolytic oxidation (PEO) technology has been developed for the rational synthesis of metal tungstate nanostructures. Using this method, ZnWO 4 and NiWO 4 nanostructures with controllable morphologies (nanorods, nanosheets and microsheets) and superior crystallinity have been synthesized. It has been found that the morphology diversity of ZnWO 4 nanostructures can be selectively tailored through tuning the electrolyte concentration and annealing temperatures, showing obvious advantages in comparison to traditional hydrothermal and sol–gel methods. Precise microscopy analyses on the cross section of the PEO coating and ZnWO 4 nanostructures confirmed that the precursors initially precipitated in the PEO coating and its surface during plasma discharge process are responsible for the nucleation and subsequent growth of metal tungstate nanostructures by thermal annealing. The method developed in this work represents a general strategy toward the rational synthesis of metal oxide nanostructures and the formation mechanism of metal tungstate nanostructures fabricated by

  3. A general strategy toward the rational synthesis of metal tungstate nanostructures using plasma electrolytic oxidation method

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Yanan; Liu, Baodan, E-mail: baodanliu@imr.ac.cn; Zhai, Zhaofeng; Liu, Xiaoyuan; Yang, Bing; Liu, Lusheng; Jiang, Xin, E-mail: xjiang@imr.ac.cn

    2015-11-30

    Graphical abstract: A general strategy for the rational synthesis of tungstate nanostructure has been developed based on plasma electrolytic oxidation (PEO) technology (up). Using this method, ZnWO{sub 4} and NiWO{sub 4} nanostructures with controllable morphologies and superior crystallinity can be easily obtained (down), showing obvious advantage in comparison with conventional hydrothermal and sol–gel methods. - Highlights: • Plasma electrolyte oxidation (PEO) method has been used for the rational synthesis of tungstate nanostructures. • ZnWO{sub 4} nanoplates have strong mechanical adhesion with porous TiO{sub 2} film substrate. • The morphology and dimensional size of ZnWO{sub 4} nanostructures can be selectively tailored by controlling the annealing temperature and growth time. • The PEO method can be widely applied to the growth of various metal oxides. - Abstract: A new method based on conventional plasma electrolytic oxidation (PEO) technology has been developed for the rational synthesis of metal tungstate nanostructures. Using this method, ZnWO{sub 4} and NiWO{sub 4} nanostructures with controllable morphologies (nanorods, nanosheets and microsheets) and superior crystallinity have been synthesized. It has been found that the morphology diversity of ZnWO{sub 4} nanostructures can be selectively tailored through tuning the electrolyte concentration and annealing temperatures, showing obvious advantages in comparison to traditional hydrothermal and sol–gel methods. Precise microscopy analyses on the cross section of the PEO coating and ZnWO{sub 4} nanostructures confirmed that the precursors initially precipitated in the PEO coating and its surface during plasma discharge process are responsible for the nucleation and subsequent growth of metal tungstate nanostructures by thermal annealing. The method developed in this work represents a general strategy toward the rational synthesis of metal oxide nanostructures and the formation mechanism of

  4. X-ray Computed Tomographic Investigation of the Porosity and Morphology of Plasma Electrolytic Oxidation Coatings

    Czech Academy of Sciences Publication Activity Database

    Zhang, X.; Aliasghari, S.; Němcová, A.; Burnett, T.L.; Kuběna, Ivo; Šmíd, Miroslav; Thompson, G.; Skeldon, P.; Withers, P.J.

    2016-01-01

    Roč. 8, č. 13 (2016), s. 8801-8810 ISSN 1944-8244 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : plasma electrolytic oxidation * porosity * scanning electron microscopy * titanium * X-ray computed tomography Subject RIV: JK - Corrosion ; Surface Treatment of Materials Impact factor: 7.504, year: 2016 http://pubs.acs.org/doi/abs/10.1021/acsami.6b00274

  5. Mg-containing hydroxyapatite coatings produced by plasma electrolytic oxidation of titanium

    Energy Technology Data Exchange (ETDEWEB)

    Antonio, Cesar Augusto; Rangel, Elidiane Cipriano; Durrant, Steven Frederick; Cruz, Nilson Cristino da, E-mail: cesar.augustoa@hotmail.com [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sorocaba, SP (Brazil). Lab. de Plasmas Tecnologicos; Delgado-Silva, Adriana de Oliveira [Universidade Federal de Sao Carlos (UFSCar), Sorocaba, SP (Brazil); Tabacniks, Manfredo H. [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Fisica

    2017-07-15

    Plasma Electrolytic Oxidation (PEO) is promising for the processing of biomaterials because it enables the production of surfaces with adjustable composition and structure. In this work, aimed at the improvement of the bioactivity of titanium, PEO has been used to grow calcium phosphide coatings on titanium substrates. The effects of the addition of magnesium acetate to the electrolytes on the composition of the coatings produced during 120 s on Ti disks using bipolar voltage pulses and solutions of calcium and magnesium acetates and sodium glycerophosphate as electrolytes have been studied. Scanning electron microscopy, X-ray energy dispersive spectroscopy, Rutherford backscattering spectroscopy, X-ray diffractometry with Rietveld refinement and profilometry were used to characterize the modified samples. Coatings composed of nearly 50 % of Mg-doped hydroxyapatite have been produced. In certain conditions up to 4% Mg can be incorporated into the coating without any observable significant structural modifications of the hydroxyapatite. (author)

  6. TiO2 Deposition on AZ31 Magnesium Alloy Using Plasma Electrolytic Oxidation

    Directory of Open Access Journals (Sweden)

    Leon White

    2013-01-01

    Full Text Available Plasma electrolytic oxidation (PEO has been used in the past as a useful surface treatment technique to improve the anticorrosion properties of Mg alloys by forming protective layer. Coatings were prepared on AZ31 magnesium alloy in phosphate electrolyte with the addition of TiO2 nanoparticles using plasma electrolytic oxidation (PEO. This present work focuses on developing a TiO2 functional coating to create a novel electrophotocatalyst while observing the surface morphology, structure, composition, and corrosion resistance of the PEO coating. Microstructural characterization of the coating was investigated by X-ray diffraction (XRD and scanning electron microscopy (SEM followed by image analysis and energy dispersive spectroscopy (EDX. The corrosion resistance of the PEO treated samples was evaluated with electrochemical impedance spectroscopy (EIS and DC polarization tests in 3.5 wt.% NaCl. The XRD pattern shows that the components of the oxide film include Mg from the substrate as well as MgO and Mg2TiO4 due to the TiO2 nanoparticle addition. The results show that the PEO coating with TiO2 nanoparticles did improve the corrosion resistance when compared to the AZ31 substrate alloy.

  7. Role of electrolyte composition on structural, morphological and in-vitro biological properties of plasma electrolytic oxidation films formed on zirconium

    International Nuclear Information System (INIS)

    M, Sandhyarani; T, Prasadrao; N, Rameshbabu

    2014-01-01

    Highlights: • Uniform oxide films were formed on zirconium by plasma electrolytic oxidation. • Silicate in electrolyte alter the growth of m-ZrO 2 from (1 ¯ 11) to (2 0 0) orientation. • Addition of KOH to electrolyte improved the corrosion resistance of oxide films. • Silicon incorporated oxide films showed higher surface roughness and wettability. • Human osteosarcoma cells were strongly adhered and spreaded on all the oxide films. - Abstract: Development of oxide films on metallic implants with a good combination of corrosion resistance, bioactivity and cell adhesion can greatly improve its biocompatibility and functionality. Thus, the present work is aimed to fabricate oxide films on metallic Zr by plasma electrolytic oxidation (PEO) in methodically varied concentrations of phosphate, silicate and KOH based electrolyte systems using a pulsed DC power source. The oxide films fabricated on Zr are characterized for its phase composition, surface morphology, chemical composition, roughness, wettability, surface energy, corrosion resistance, apatite forming ability and osteoblast cell adhesion. Uniform films with thickness varying from 6 to 11 μm are formed. XRD patterns of all the PEO films showed the predominance of monoclinic zirconia phase. The film formed in phosphate + KOH electrolyte showed superior corrosion resistance, which can be ascribed to its pore free morphology. The films formed in silicate electrolyte showed higher apatite forming ability with good cell adhesion and spreading over its surface which is attributed to its superior surface roughness and wettability characteristics. Among the five different electrolyte systems employed in the present study, the PEO film formed in an electrolyte system with phosphate + silicate + KOH showed optimum corrosion resistance, apatite forming ability and biocompatibility

  8. Corrosion-electrochemical characteristics of oxide-carbide and oxide-nitride coatings formed by electrolytic plasma

    International Nuclear Information System (INIS)

    Tomashov, N.D.; Chukalovskaya, T.V.; Medova, I.L.; Duradzhi, V.N.; Plavnik, G.M.

    1990-01-01

    The composition, structure, microhardness and corrosion-electrochemical properties of oxide-carbide and oxide-nitride coatings on titanium in 5n H 2 SO 4 , 50 deg, produced by the method of chemical-heat treatment in electrolytic plasma, containing saturation components of nitrogen and carbon, were investigated. It is shown that the coatings produced have increased hardness, possess high corrosion resistance in sulfuric acid solution at increased temperature, as to their electrochemcial behaviour they are similar to titanium carbide and nitride respectively. It is shown that high corrosion resistance is ensured by electrochemical mechanism of the oxide-carbide and oxide-nitride coating protection

  9. Enhanced mechanical properties and increased corrosion resistance of a biodegradable magnesium alloy by plasma electrolytic oxidation (PEO)

    International Nuclear Information System (INIS)

    White, Leon; Koo, Youngmi; Neralla, Sudheer; Sankar, Jagannathan; Yun, Yeoheung

    2016-01-01

    Highlights: • Plasma electrolytic oxidation (PEO) method was developed to control corrosion, porosity, and mechanical property. • Mechanical properties of PEO-coated AZ31 alloys were affected by the different electrolyte. • Mechanical properties and corrosion resistance of PEO-coated AZ31 alloys were compared with uncoated one. - Abstract: We report the enhanced mechanical properties of AZ31 magnesium alloys by plasma electrolytic oxidation (PEO) coating in NaOH, Na_2SiO_3, KF and NaH_2PO_4·2H_2O containing electrolytes. Mechanical properties including wear resistance, surface hardness and elastic modulus were increased for PEO-coated AZ31 Mg alloys (PEO-AZ31). DC polarization in Hank's solution indicating that the corrosion resistance significantly increased for PEO-coating in KF-contained electrolyte. Based on these results, the PEO coating method shows promising potential for use in biodegradable implant applications where tunable corrosion and mechanical properties are needed.

  10. Tribological and Corrosion Properties of Coatings Produced by Plasma Electrolytic Oxidation on the ZA27 Alloy

    Science.gov (United States)

    Li, Guangyin; Mao, Yifan; Li, Zhijian; Wang, Linlin; DaCosta, Herbert

    2018-05-01

    In this paper, a continuous and dense coating was deposited on samples of the ZA27 alloy through the plasma electrolytic oxidation (PEO) process to improve its wear and corrosion performance. A nontoxic and environmentally friendly inorganic salt, Na2SiO3, is chosen as electrolytes with different concentrations. The effect of the concentration of Na2SiO3 aqueous solutions on the coating performances was investigated. The coatings with 3Al2O3·2SiO2 (mullite), Zn2SiO4 and Al2O3 (either crystal phase or with some amorphous SiO2 phases) were formed by the PEO processes. It was found that the coating thickness increased with the increase in electrolyte concentration. However, the wear and corrosion resistance performance of the coatings did not improve as the coating's thickness increased. This was due to the fact that the coating produced with electrolytes of 10 g/L has a porous structure with large pore size. Among all the samples, coating produced by 15 g/L Na2SiO3 has the best wear and corrosion resistance, which is attributed to its continuous and dense structure with thickness of about 47 μm.

  11. Tribological and Corrosion Properties of Coatings Produced by Plasma Electrolytic Oxidation on the ZA27 Alloy

    Science.gov (United States)

    Li, Guangyin; Mao, Yifan; Li, Zhijian; Wang, Linlin; DaCosta, Herbert

    2018-04-01

    In this paper, a continuous and dense coating was deposited on samples of the ZA27 alloy through the plasma electrolytic oxidation (PEO) process to improve its wear and corrosion performance. A nontoxic and environmentally friendly inorganic salt, Na2SiO3, is chosen as electrolytes with different concentrations. The effect of the concentration of Na2SiO3 aqueous solutions on the coating performances was investigated. The coatings with 3Al2O3·2SiO2 (mullite), Zn2SiO4 and Al2O3 (either crystal phase or with some amorphous SiO2 phases) were formed by the PEO processes. It was found that the coating thickness increased with the increase in electrolyte concentration. However, the wear and corrosion resistance performance of the coatings did not improve as the coating's thickness increased. This was due to the fact that the coating produced with electrolytes of 10 g/L has a porous structure with large pore size. Among all the samples, coating produced by 15 g/L Na2SiO3 has the best wear and corrosion resistance, which is attributed to its continuous and dense structure with thickness of about 47 μm.

  12. Growth kinetics and morphology of plasma electrolytic oxidation coating on aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Erfanifar, Eliyas; Aliofkhazraei, Mahmood, E-mail: maliofkh@gmail.com; Fakhr Nabavi, Houman; Sharifi, Hossein; Rouhaghdam, Alireza Sabour

    2017-01-01

    Plasma electrolytic oxidation (PEO) was carried out on AA1190 aluminum alloy in mixed silicate-phosphate-based electrolyte in order to fabricate ceramic coating under constant current density. The variations of PEO coating duration with kinetics, surface roughness, amount and size of discharge channels were studied with respect to PEO processing time. The growth mechanism of the ceramic coating was described considering a variation of volume and diameters of discharge channels and pancakes during the PEO. Scanning electron microscope (SEM), atomic force microscope (AFM), and roughness tester were used to study the plasma discharge channels of the PEO coatings. In addition, the effect of alumina nanoparticles in the electrolyte as the suspension was studied on the geometric parameters of discharge channels. It seems that the nanoparticles are adsorbed to the locations of erupted molten oxide, where the dielectric breakdown occurs. Nanoparticles were embedded in the dense oxide layer and were adsorbed at the walls of voids and coatings surface. As a result, they caused significant changes in roughness parameters of the samples containing nanoparticles compared to those without nanoparticles. The obtained results showed that growth kinetics followed a linear trend with respect to PEO coating duration. It was also observed that in the absence of alumina nanoparticles, the average volume of the pancakes is 150% greater than the ones fabricated in the suspension of nanoparticles. Besides, increasing the PEO coating duration leads to adsorbing more nanoparticles on the coating surface, filling the voids, and flattening the surface, and alterations in R{sub v}, R{sub sk}, and R{sub lo} parameters. Correlation between the diameter of discharge channel (d{sub c}) and thickness of the pancake (h) also showed a linear relation. - Highlights: • Precise calculation of thickness of pancake with AFM. • Study of different roughness parameters for PEO coating. • Calculation

  13. Growth kinetics and morphology of plasma electrolytic oxidation coating on aluminum

    International Nuclear Information System (INIS)

    Erfanifar, Eliyas; Aliofkhazraei, Mahmood; Fakhr Nabavi, Houman; Sharifi, Hossein; Rouhaghdam, Alireza Sabour

    2017-01-01

    Plasma electrolytic oxidation (PEO) was carried out on AA1190 aluminum alloy in mixed silicate-phosphate-based electrolyte in order to fabricate ceramic coating under constant current density. The variations of PEO coating duration with kinetics, surface roughness, amount and size of discharge channels were studied with respect to PEO processing time. The growth mechanism of the ceramic coating was described considering a variation of volume and diameters of discharge channels and pancakes during the PEO. Scanning electron microscope (SEM), atomic force microscope (AFM), and roughness tester were used to study the plasma discharge channels of the PEO coatings. In addition, the effect of alumina nanoparticles in the electrolyte as the suspension was studied on the geometric parameters of discharge channels. It seems that the nanoparticles are adsorbed to the locations of erupted molten oxide, where the dielectric breakdown occurs. Nanoparticles were embedded in the dense oxide layer and were adsorbed at the walls of voids and coatings surface. As a result, they caused significant changes in roughness parameters of the samples containing nanoparticles compared to those without nanoparticles. The obtained results showed that growth kinetics followed a linear trend with respect to PEO coating duration. It was also observed that in the absence of alumina nanoparticles, the average volume of the pancakes is 150% greater than the ones fabricated in the suspension of nanoparticles. Besides, increasing the PEO coating duration leads to adsorbing more nanoparticles on the coating surface, filling the voids, and flattening the surface, and alterations in R v , R sk , and R lo parameters. Correlation between the diameter of discharge channel (d c ) and thickness of the pancake (h) also showed a linear relation. - Highlights: • Precise calculation of thickness of pancake with AFM. • Study of different roughness parameters for PEO coating. • Calculation the amount of

  14. Solid oxide fuel cell electrolytes produced via very low pressure suspension plasma spray and electrophoretic deposition

    Science.gov (United States)

    Fleetwood, James D.

    Solid oxide fuel cells (SOFCs) are a promising element of comprehensive energy policies due to their direct mechanism for converting the oxidization of fuel, such as hydrogen, into electrical energy. Both very low pressure plasma spray and electrophoretic deposition allow working with high melting temperature SOFC suspension based feedstock on complex surfaces, such as in non-planar SOFC designs. Dense, thin electrolytes of ideal composition for SOFCs can be fabricated with each of these processes, while compositional control is achieved with dissolved dopant compounds that are incorporated into the coating during deposition. In the work reported, sub-micron 8 mole % Y2O3-ZrO2 (YSZ) and gadolinia-doped ceria (GDC), powders, including those in suspension with scandium-nitrate dopants, were deposited on NiO-YSZ anodes, via very low pressure suspension plasma spray (VLPSPS) at Sandia National Laboratories' Thermal Spray Research Laboratory and electrophoretic deposition (EPD) at Purdue University. Plasma spray was carried out in a chamber held at 320 - 1300 Pa, with the plasma composed of argon, hydrogen, and helium. EPD was characterized utilizing constant current deposition at 10 mm electrode separation, with deposits sintered from 1300 -- 1500 °C for 2 hours. The role of suspension constituents in EPD was analyzed based on a parametric study of powder loading, powder specific surface area, polyvinyl butyral (PVB) content, polyethyleneimine (PEI) content, and acetic acid content. Increasing PVB content and reduction of particle specific surface area were found to eliminate the formation of cracks when drying. PEI and acetic acid content were used to control suspension stability and the adhesion of deposits. Additionally, EPD was used to fabricate YSZ/GDC bilayer electrolyte systems. The resultant YSZ electrolytes were 2-27 microns thick and up to 97% dense. Electrolyte performance as part of a SOFC system with screen printed LSCF cathodes was evaluated with peak

  15. Gibbs energy calculation of electrolytic plasma channel with inclusions of copper and copper oxide with Al-base

    Science.gov (United States)

    Posuvailo, V. M.; Klapkiv, M. D.; Student, M. M.; Sirak, Y. Y.; Pokhmurska, H. V.

    2017-03-01

    The oxide ceramic coating with copper inclusions was synthesized by the method of plasma electrolytic oxidation (PEO). Calculations of the Gibbs energies of reactions between the plasma channel elements with inclusions of copper and copper oxide were carried out. Two methods of forming the oxide-ceramic coatings on aluminum base in electrolytic plasma with copper inclusions were established. The first method - consist in the introduction of copper into the aluminum matrix, the second - copper oxide. During the synthesis of oxide ceramic coatings plasma channel does not react with copper and copper oxide-ceramic included in the coating. In the second case is reduction of copper oxide in interaction with elements of the plasma channel. The content of oxide-ceramic layer was investigated by X-ray and X-ray microelement analysis. The inclusions of copper, CuAl2, Cu9Al4 in the oxide-ceramic coatings were found. It was established that in the spark plasma channels alongside with the oxidation reaction occurs also the reaction aluminothermic reduction of the metal that allows us to dope the oxide-ceramic coating by metal the isobaric-isothermal potential oxidation of which is less negative than the potential of the aluminum oxide.

  16. Plasma electrolytic oxidation of magnesium and its alloys: Mechanism, properties and applications

    Directory of Open Access Journals (Sweden)

    Gh. Barati Darband

    2017-03-01

    Full Text Available Plasma Electrolyte Oxidation (PEO process has increasingly been employed to improve magnesium surface properties by fabrication of an MgO-based coating. Originating from conventional anodizing procedures, this high-voltage process produces an adhesive ceramic film on the surface. The present article provides a comprehensive review around mechanisms of PEO coatings fabrication and their different properties. Due to complexity of PEO coatings formation, a complete explanation regarding fabrication mechanisms of PEO coatings has not yet been proposed; however, the most important advancements in the field of fabrication mechanisms of PEO coatings were gathered in this work. Mechanisms of PEO coatings fabrication on magnesium were reviewed considering voltage–time plots, optical spectrometry, acoustic emission spectrometry and electronic properties of the ceramic film. Afterwards, the coatings properties, affecting parameters and improvement strategies were discussed. In addition, corrosion resistance of coatings, important factors in corrosion resistance and methods for corrosion resistance improvement were considered. Tribological properties (important factors and improvement methods of coatings were also studied. Since magnesium and its alloys are broadly used in biological applications, the biological properties of PEO coatings, important factors in their biological performance and existing methods for improvement of coatings were explained. Addition of ceramic based nanoparticles and formation of nanocomposite coatings may considerably influence properties of plasma electrolyte oxidation coatings. Nanocomposite coatings properties and nanoparticles adsorption mechanisms were included in a separate sector. Another method to improve coatings properties is formation of hybrid coatings on PEO coatings which was discussed in the end.

  17. Spectroscopic study of plasma during electrolytic oxidation of magnesium- and aluminium-alloy

    International Nuclear Information System (INIS)

    Jovović, J.; Stojadinović, S.; Šišović, N.M.; Konjević, N.

    2012-01-01

    We present the results of an optical emission spectroscopy study of Plasma during Electrolytic Oxidation (PEO) of magnesium- and aluminum-alloy. Plasma electron number density N e diagnostics is performed either from the H β line shape or from the width or shift of non-hydrogenic ion lines of aluminum and magnesium. The line profile analysis of the H β suggests presence of two PEO processes characterized by relatively low electron number densities N e ≈1.2×10 15 cm −3 and N e ≈2.3×10 16 cm −3 . Apart from these two low N e processes, there is the third one related to the ejection of evaporated anode material through micro-discharge channels. This process is characterized by larger electron density N e =(1.2–1.6)10 17 cm −3 , which is detected from the shape and shift of aluminum and magnesium singly charged ion lines. Two low N e values detected from the H β and large N e measured from the widths and shift of ion lines suggest presence of three types of discharges during PEO with aluminum- and magnesium-alloy anode. On the basis of present and earlier results one can conclude that low N e processes do not depend upon anode material or electrolyte composition. The electron temperature of 4000 K and 33,000 K are determined from relative intensities of Mg I and O II lines, respectively. The attention is drawn to the possibility of N e application for T e evaluation using Saha equation what is of importance for PEO metal plasma characterization. During the course of this study, difficulties in the analysis of spectral line shapes are encountered and the ways to overcome some of the obstacles are demonstrated. -- Highlights: ► Optical emission spectroscopy of plasma during electrolytic oxidation. ► Spectral line profiles of the H-beta and non-hydrogenic singly charged ion lines of aluminum and magnesium. ► Experimental line profiles with complex structure. ► Three plasma processes involved. ► The application of Saha equation for the process

  18. Data on the surface morphology of additively manufactured Ti-6Al-4V implants during processing by plasma electrolytic oxidation

    Directory of Open Access Journals (Sweden)

    Ingmar A.J. van Hengel

    2017-08-01

    Full Text Available Additively manufactured Ti-6Al-4V implants were biofunctionalized using plasma electrolytic oxidation. At various time points during this process scanning electron microscopy imaging was performed to analyze the surface morphology (van Hengel et al., 2017 [1]. This data shows the changes in surface morphology during plasma electrolytic oxidation. Data presented in this article are related to the research article “Selective laser melting porous metallic implants with immobilized silver nanoparticles kill and prevent biofilm formation by methicillin-resistant Staphylococcus aureus” (van Hengel et al., 2017 [1].

  19. Effect of electrolyte additives on performance of plasma electrolytic oxidation films formed on magnesium alloy AZ91D

    International Nuclear Information System (INIS)

    Duan, Hongping; Yan, Chuanwei; Wang, Fuhui

    2007-01-01

    Various plasma electrolytic oxidation (PEO) films were prepared on magnesium alloy AZ91D in a silicate bath with different additives such as phosphate, fluoride and borate. Effects of the additives on chemical composition and corrosion resistance of the PEO films were examined by means of scanning electron microscopy (SEM), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in 3.5% NaCl solution. The results showed that the PEO films obtained in solutions with both borate and fluoride had better corrosion resistance. In order to understand the corrosion mechanism of PEO films on magnesium alloy AZ91D, electronic property of the magnesium electrode with PEO films was studied by Mott-Schottky approach in a solution containing borate and chloride. The results indicated that magnesium electrodes with and without PEO films all exhibited n-type semiconducting property. However, in comparison with the magnesium electrode treated in solutions containing phosphate or borate, the electrode treated in solutions containing both borate and fluoride (M-film) had lower donor concentration and much negative flat band potential; therefore, the M-film had lower reactivity and higher corrosion resistance

  20. Transmission electron microscopy of coatings formed by plasma electrolytic oxidation of titanium.

    Science.gov (United States)

    Matykina, E; Arrabal, R; Skeldon, P; Thompson, G E

    2009-05-01

    Transmission electron microscopy and supporting film analyses are used to investigate the changes in composition, morphology and structure of coatings formed on titanium during DC plasma electrolytic oxidation in a calcium- and phosphorus-containing electrolyte. The coatings are of potential interest as bioactive surfaces. The initial barrier film, of mixed amorphous and nanocrystalline structure, formed below the sparking voltage of 180 V, incorporates small amounts of phosphorus and calcium species, with phosphorus confined to the outer approximately 63% of the coating thickness. On commencement of sparking, calcium- and phosphorus-rich amorphous material forms at the coating surface, with local heating promoting crystallization in underlying and adjacent anodic titania. The amorphous material thickens with increased treatment time, comprising almost the whole of the approximately 5.7-microm-thick coating formed at 340 V. At this stage, the coating is approximately 4.4 times thicker than the oxidized titanium, with a near-surface composition of about 12 at.% Ti, 58 at.% O, 19 at.% P and 11 at.% Ca. Further, the amount of titanium consumed in forming the coating is similar to that calculated from the anodizing charge, although there may be non-Faradaic contributions to the coating growth.

  1. Enhanced mechanical properties and increased corrosion resistance of a biodegradable magnesium alloy by plasma electrolytic oxidation (PEO).

    Science.gov (United States)

    White, Leon; Koo, Youngmi; Neralla, Sudheer; Sankar, Jagannathan; Yun, Yeoheung

    2016-06-01

    We report the enhanced mechanical properties of AZ31 magnesium alloys by plasma electrolytic oxidation (PEO) coating in NaOH, Na 2 SiO 3 , KF and NaH 2 PO 4 ·2H 2 O containing electrolytes. Mechanical properties including wear resistance, surface hardness and elastic modulus were increased for PEO-coated AZ31 Mg alloys (PEO-AZ31). DC polarization in Hank's solution indicating that the corrosion resistance significantly increased for PEO-coating in KF-contained electrolyte. Based on these results, the PEO coating method shows promising potential for use in biodegradable implant applications where tunable corrosion and mechanical properties are needed.

  2. Characterization of coatings formed on AZX magnesium alloys by plasma electrolytic oxidation

    Science.gov (United States)

    Anawati, Anawati; Gumelar, Muhammad Dikdik

    2018-05-01

    Plasma Electrolytic Oxidation (PEO) is an electrochemical anodization process which involves the application of a high voltage to create intense plasma on a metal surface to form a ceramic type of oxide. The resulted coating exhibits high wear resistance and good corrosion barrier which are suitable to enhance the performance of biodegradable Mg alloys. In this work, the role of alloying element Ca in modifying the characteristics of PEO layer formed on AZ61 series magnesium alloys was investigated. PEO treatment was conducted on AZ61, AZX611, and AZX612 alloys in 0.5 M Na3PO4 solution at a constant current of 200 A/m2 at 25°C for 8 min. The resulted coatings were characterized by field emission-scanning electron microscope (FESEM), X-ray diffraction spectroscopy (XRD), and X-ray fluorescence spectroscopy (XRF), as well as hardness test. The presence of alloying element Ca in the AZ61 alloys accelerated the PEO coatings formation without altering the coating properties significantly. The coating formed on AZX specimen was slightly thicker ( 14-17 µm) than that of formed onthe AZ specimens ( 13 µm). Longer exposure time to plasma discharge was the reason for faster thickening of the coating layer on AZX specimen. XRD detected a similar crystalline oxide phase of Mg3(PO4)2 in the oxide formed on all of the specimens. Zn was highly incorporated in the coatings with a concentration in the range 24-30 wt%, as analyzed by XRF. Zn compound might exist in amorphous phases. The microhardness test on the coatings revealed similar average hardness 124 HVon all of the specimens.

  3. IMPLEMENTATION OF A SWITCHED POWER SUPPLY FOR THE PLASMA ELECTROLYTIC OXIDATION TECHNIQUE

    Directory of Open Access Journals (Sweden)

    Fernando Gordillo-Delgado

    2017-07-01

    Full Text Available A switched-mode power supply was implemented for using in the Plasma Electrolytic Oxidation (PEO technique. The electronic devices are inexpensive and ordinarily used, which facilitates the construction of the system. A MICROCHIP microcontroller was used for generating a digital signal with frequency and duty cycle control; a capacitor bank and a diode bridge were also used for rectifying the input signal from the electrical network. The management of the output voltage was made with an arrangement of MOSFET transistors in the "low side" configuration; the measurement of the current was made with a Hall Effect sensor and using the USB communication the data was sent to a computer for visualization with a LabVIEW algorithm. The power supply was tested for creating microcavities in a titanium sheet with the aim of forming nanostructures of titanium dioxide.

  4. Data on the surface morphology of additively manufactured Ti-6Al-4V implants during processing by plasma electrolytic oxidation

    NARCIS (Netherlands)

    van Hengel, I.A.J. (Ingmar A.J.); M. Riool (Martijn); L.E. Fratila-Apachitei (L.); J. Witte-Bouma (Janneke); E. Farrell (Eric); A.A. Zadpoor (Amir Abbas); S.A.J. Zaat (Sebastiaan); I. Apachitei (I.)

    2017-01-01

    textabstractAdditively manufactured Ti-6Al-4V implants were biofunctionalized using plasma electrolytic oxidation. At various time points during this process scanning electron microscopy imaging was performed to analyze the surface morphology (van Hengel et al., 2017) [1]. This data shows the

  5. Data on the surface morphology of additively manufactured Ti-6Al-4V implants during processing by plasma electrolytic oxidation

    NARCIS (Netherlands)

    van Hengel, I.A.J.; Riool, Martijn; Fratila-Apachitei, E.L.; Witte-Bouma, Janneke; Farrell, Eric; Zadpoor, A.A.; Zaat, Sebastian A.J.; Apachitei, I.

    2017-01-01

    Additively manufactured Ti-6Al-4V implants were biofunctionalized using plasma electrolytic oxidation. At various time points during this process scanning electron microscopy imaging was performed to analyze the surface morphology (van Hengel et al., 2017) [1]. This data shows the changes in

  6. Hydroxyapatite coatings containing Zn and Si on Ti-6Al-4Valloy by plasma electrolytic oxidation

    Science.gov (United States)

    Hwang, In-Jo; Choe, Han-Cheol

    2018-02-01

    In this study, hydroxyapatite coatings containing Zn and Si on Ti-6Al-4Valloy by plasma electrolytic oxidation were researched using various experimental instruments. The pore size is depended on the electrolyte concentration and the particle size and number of pore increase on surface part and pore part. In the case of Zn/Si sample, pore size was larger than that of Zn samples. The maximum size of pores decreased and minimum size of pores increased up to 10Zn/Si and Zn and Si affect the formation of pore shapes. As Zn ion concentration increases, the size of the particle tends to increase, the number of particles on the surface part is reduced, whereas the size of the particles and the number of particles on pore part increased. Zn is mainly detected at pore part, and Si is mainly detected at surface part. The crystallite size of anatase increased as the Zn ion concentration, whereas, in the case of Si ion added, crystallite size of anatase decreased.

  7. Zirconia based ceramic coating on a metal with plasma electrolytic oxidation

    Science.gov (United States)

    Akatsu, T.; Kato, T.; Shinoda, Y.; Wakai, F.

    2011-10-01

    We challenge to fabricate a thermal barrier coating (TBC) made of ZrO2 based ceramics on a Ni based single crystal superalloy with plasma electrolytic oxidation (PEO) by incorporating metal species from electrolyte into the coating. The PEO process is carried out on the superalloy galvanized with aluminium for 15min in Na4O7P4 solution for an oxygen barrier coating (OBC) and is followed by PEO in K2[Zr(CO3)2(OH)2] solution for TBC. We obtained the following results; (1) Monoclinic-, tetragonal-, cubic-ZrO2 crystals were detected in TBC. (2) High porosity with large pores was observed near the interface between OBC and TBC. The fine grain structure with a grain size of about 300nm was typically observed. (3) The adhesion strength between PEO coatings and substrate was evaluated to be 26.8±6.6MPa. At the adhesion strength test, PEO coatings fractured around the interface between OBC and TBC. The effect of coating structure on adhesion strength is explained through the change in spark discharge during PEO process.

  8. Non-electrolytic synthesis of copper oxide/carbon nanocomposite by surface plasma in super-dehydrated ethanol

    Science.gov (United States)

    Kozak, Dmytro S.; Sergiienko, Ruslan A.; Shibata, Etsuro; Iizuka, Atsushi; Nakamura, Takashi

    2016-02-01

    Electrolytic processes are widely used to synthesize different nanomaterials and it does not depend on what kind of the method has been applied (wet-chemistry, sonochemistry, plasma chemistry, electrolysis and so on). Generally, the reactions in the electrolyte are considered to be reduction/oxidation (REDOX) reactions between chemical reagents or the deposition of matter on the electrodes, in line with Faraday’s law. Due to the presence of electroconductive additives in any electrolyte, the polarization effect of polar molecules conducting an electrical current disappears, when external high-strength electric field is induced. Because initially of the charge transfer always belongs of electroconductive additive and it does not depend on applied voltage. The polarization of ethanol molecules has been applied to conduct an electric current by surface plasma interaction for the synthesis of a copper oxide/carbon nanocomposite material.

  9. Real-time imaging, spectroscopy, and structural investigation of cathodic plasma electrolytic oxidation of molybdenum

    Energy Technology Data Exchange (ETDEWEB)

    Stojadinović, Stevan, E-mail: sstevan@ff.bg.ac.rs; Tadić, Nenad; Šišović, Nikola M.; Vasilić, Rastko [Faculty of Physics, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia)

    2015-06-21

    In this paper, the results of the investigation of cathodic plasma electrolytic oxidation (CPEO) of molybdenum at 160 V in a mixed solution of borax, water, and ethylene glycol are presented. Real-time imaging and optical emission spectroscopy were used for the characterization of the CPEO. During the process, vapor envelope is formed around the cathode and strong electric field within the envelope caused the generation of plasma discharges. The spectral line shape analysis of hydrogen Balmer line H{sub β} (486.13 nm) shows that plasma discharges are characterized by the electron number density of about 1.4 × 10{sup 21 }m{sup −3}. The electron temperature of 15 000 K was estimated by measuring molybdenum atomic lines intensity. Surface morphology, chemical, and phase composition of coatings formed by CPEO were characterized by scanning electron microscopy with energy dispersive x-ray spectroscopy and x-ray diffraction. The elemental components of CPEO coatings are Mo and O and the predominant crystalline form is MoO{sub 3}.

  10. Corrosion protection performance of single and dual Plasma Electrolytic Oxidation (PEO) coating for aerospace applications

    International Nuclear Information System (INIS)

    Madhan Kumar, A.; Kwon, Sun Hwan; Jung, Hwa Chul; Shin, Kwang Seon

    2015-01-01

    Plasma Electrolytic Oxidation (PEO) coatings are known to be one of the most appropriate method for corrosion protection of magnesium (Mg) alloy. The improvement of PEO coatings and the optimization of their surface aspects are of major importance. In this current work, the influence of dual PEO coating on strip-cast AZ31 Mg alloy substrate has been evaluated with the aim of improving the surface and corrosion protection aspects. For this purpose, AZ31 Mg substrates are subjected to single and dual PEO processing in silicate and phosphate electrolyte under similar condition. Scanning electron microscopy (SEM) analysis confirmed that the number of pores in PEO coating processed in silicate electrolyte is higher than others. X-ray diffraction analysis of PEO coatings showed that the surface coating is mainly comprised of Mg 2 SiO 4 , Mg 3 (PO 4 ) 2 and MgO with different quantity based on PEO processing. Compared with the AZ31 Mg, the corrosion potential (E corr ) of both type PEO coatings was positively shifted about 250–400 mV and the corrosion current density (i corr ) was lowered by 3-4 orders of magnitude as result of adequate corrosion protection to the Mg alloy in 3.5% NaCl solution. All of the observation obviously showed that the dual PEO coating provides better corrosion protection performance than their respective single due to its synergistic beneficial effect. - Highlights: • Influence of dual PEO coating on AZ31 Mg alloy substrate was evaluated. • XRD confirmed formation of thin MgO inner, Mg 3 (PO 4 ) 2 and Mg 2 SiO 4 outer layer. • SEM results showed uniform coating with no cracks and relatively less micro pores. • Micro hardness of dual PEO coatings is higher than single PEO coatings. • Dual coating provides superior corrosion performance due to its synergistic effect

  11. Composite plasma electrolytic oxidation to improve the thermal radiation performance and corrosion resistance on an Al substrate

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Donghyun [Department of Materials Science and Engineering, Pusan National University, Busan 46241 (Korea, Republic of); Sung, Dahye [Department of Materials Science and Engineering, Pusan National University, Busan 46241 (Korea, Republic of); Korea Institute of Industrial Technology (KITECH), Busan 46742 (Korea, Republic of); Lee, Junghoon [Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ 07030 (United States); Kim, Yonghwan [Korea Institute of Industrial Technology (KITECH), Busan 46742 (Korea, Republic of); Chung, Wonsub, E-mail: wschung1@pusan.ac.kr [Department of Materials Science and Engineering, Pusan National University, Busan 46241 (Korea, Republic of)

    2015-12-01

    Highlights: • Composite plasma electrolytic oxidation was performed using dispersed CuO particles in convectional PEO electrolyte. • Thermal radiation performance and corrosion resistance were examined by FT-IR spectroscopy and electrochemical methods, respectively. • Deposited copper oxide on the surface of the Al substrate was enhanced the corrosion resistance and the emissivity compared with the conventional PEO. - Abstract: A composite plasma electrolytic oxidation (PEO) was performed for enhancing the thermal radiation performance and corrosion resistance on an Al alloy by dispersing cupric oxide (CuO) particles in a conventional PEO electrolyte. Cu-based oxides (CuO and Cu{sub 2}O) formed by composite PEO increased the emissivity of the substrate to 0.892, and made the surface being dark color, similar to a black body, i.e., an ideal radiator. In addition, the corrosion resistance was analyzed using potentio-dynamic polarization and electrochemical impedance spectroscopy tests in 3.5 wt.% NaCl aqueous solution. An optimum condition of 10 ampere per square decimeter (ASD) current density and 30 min processing time produced appropriate surface morphologies and coating thicknesses, as well as dense Cu- and Al-based oxides that constituted the coating layers.

  12. Effect of substrate and cathode parameters on the properties of suspension plasma sprayed solid oxide fuel cell electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Waldbillig, D.; Tang, Z.; Burgess, A. [British Columbia Univ., Vancouver, BC (Canada); Kesler, O. [Toronto Univ., ON (Canada)

    2008-07-01

    An axial injection suspension plasma spray system has been used to produce layers of fully stabilized yttriastabilized zirconia (YSZ) that could be used as solid oxide fuel cell (SOFC) electrolytes. Suspension plasma spraying is a promising technique for the rapid production of coatings with fine microstructures and controlled porosity without requiring a post-deposition heat treatment. This new manufacturing technique to produce SOFC active layers requires the build up of a number of different plasma sprayed SOFC functional layers (cathode, electrolyte and anode) sequentially on top of each other. To understand the influence of the substrate and previouslydeposited coating layers on subsequent coating layer properties, YSZ layers were deposited on top of plasma sprayed composite lanthanum strontium manganite (LSM)/YSZ cathode layers that were first deposited on porous ferritic stainless steel substrates. Three layer half cells consisting of the porous steel substrate, composite cathode, and suspension plasma sprayed electrolyte layer were then characterized. A systematic study was performed in order to investigate the effect of parameters such as substrate and cathode layer roughness, substrate surface pore size, and cathode microstructure and thickness on electrolyte deposition efficiency, cathode and electrolyte permeability, and layer microstructure. (orig.)

  13. Effects of plasma electrolytic oxidation process on the mechanical properties of additively manufactured porous biomaterials.

    Science.gov (United States)

    Gorgin Karaji, Zahra; Hedayati, Reza; Pouran, Behdad; Apachitei, Iulian; Zadpoor, Amir A

    2017-07-01

    Metallic porous biomaterials are recently attracting more attention thanks to the additive manufacturing techniques which help produce more complex structures as compared to conventional techniques. On the other hand, bio-functional surfaces on metallic biomaterials such as titanium and its alloys are necessary to enhance the biological interactions with the host tissue. This study discusses the effect of plasma electrolytic oxidation (PEO), as a surface modification technique to produce bio-functional layers, on the mechanical properties of additively manufactured Ti6Al4V scaffolds based on the cubic unit cell. For this purpose, the PEO process with two different oxidation times was applied on scaffolds with four different values of relative density. The effects of the PEO process were studied by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), optical microscopy as well as static and dynamic (fatigue) mechanical testing under compression. SEM results indicated pore formation on the surface of the scaffolds after oxidation with a thickness of 4.85±0.36μm of the oxide layer after 2min and 9.04±2.27μm after 5min oxidation (based on optical images). The static test results showed the high effect of relative density of porous structure on its mechanical properties. However, oxidation did not influence most of the mechanical properties such as maximum stress, yield stress, plateau stress, and energy absorption, although its effect on the elastic modulus was considerable. Under fatigue loading, none of the scaffolds failed even after 10 6 loading cycles at 70% of their yield stress. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Bioactivity and biocompatibility of hydroxyapatite-based bioceramic coatings on zirconium by plasma electrolytic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Aktuğ, Salim Levent, E-mail: saktug@gtu.edu.tr [The Department of Materials Science and Engineering, Gebze Technical University, Gebze, Kocaeli 41400 (Turkey); Durdu, Salih, E-mail: durdusalih@gmail.com [The Department of Industrial Engineering, Giresun University, Merkez, Giresun 28200 (Turkey); Yalçın, Emine, E-mail: emine.yalcin@giresun.edu.tr [The Department of Biology, Giresun University, Merkez, Giresun 28200 (Turkey); Çavuşoğlu, Kültigin, E-mail: kultigin.cavusoglu@giresun.edu.tr [The Department of Biology, Giresun University, Merkez, Giresun 28200 (Turkey); Usta, Metin, E-mail: ustam@gtu.edu.tr [The Department of Materials Science and Engineering, Gebze Technical University, Gebze, Kocaeli 41400 (Turkey); Materials Institute, Marmara Research Center, TUBITAK, Gebze, Kocaeli 41470 (Turkey)

    2017-02-01

    In the present work, hydroxyapatite (HAP)-based plasma electrolytic oxide (PEO) coatings were produced on zirconium at different current densities in a solution containing calcium acetate and β-calcium glycerophosphate by a single step. The phase structure, surface morphology, functional groups, thickness and roughness of the coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), eddy current method and surface profilometer, respectively. The phases of cubic-zirconia, calcium zirconate and HAP were detected by XRD. The amount of HAP and calcium zirconate increased with increasing current density. The surface of the coatings was very porous and rough. Moreover, bioactivity and biocompatibility of the coatings were analyzed in vitro immersion simulated body fluid (SBF) and MTT (3-(4,5-dimethyl thiazol-2yl)-2,5-diphenyl tetrazolium bromide) assay, hemolysis assay and bacterial formation. The apatite-forming ability of the coatings was evaluated after immersion in SBF up to 28 days. After immersion, the bioactivity of HAP-based coatings on zirconium was greater than the ones of uncoated zirconium and zirconium oxide-based surface. The bioactivity of PEO surface on zirconium was significantly improved under SBF conditions. The bacterial adhesion of the coatings decreased with increasing current density. The bacterial adhesion of the coating produced at 0.370 A/cm{sup 2} was minimum compared to uncoated zirconium coated at 0.260 and 0.292 A/cm{sup 2}. The hemocompatibility of HAP-based surfaces was improved by PEO. The cell attachment and proliferation of the PEO coatings were better than the one of uncoated zirconium according to MTT assay results. - Highlights: • Hydroxyapatite was formed on zirconium at different current densities by single-step plasma electrolytic oxidation. • The amount of hydroxyapatite and calcium-based phases increased with

  15. Plasma electrolytic oxidation treatment mode influence on corrosion properties of coatings obtained on Zr-1Nb alloy in silicate-phosphate electrolyte

    Science.gov (United States)

    Farrakhov, R. G.; Mukaeva, V. R.; Fatkullin, A. R.; Gorbatkov, M. V.; Tarasov, P. V.; Lazarev, D. M.; Babu, N. Ramesh; Parfenov, E. V.

    2018-01-01

    This research is aimed at improvement of corrosion properties for Zr-1Nb alloy via plasma electrolytic oxidation (PEO). The coatings obtained in DC, pulsed unipolar and pulsed bipolar modes were assessed using SEM, XRD, PDP and EIS techniques. It was shown that pulsed unipolar mode provides the PEO coatings having promising combination of the coating thickness, surface roughness, porosity, corrosion potential and current density, and charge transfer resistance, all contributing to corrosion protection of the zirconium alloy for advanced fuel cladding applications.

  16. High Current Plasma Electrolytic Oxidation Coating Processes for Wear and Corrosion Prevention of Al 2024

    Science.gov (United States)

    Wang, Rui

    Plasma electrolytic oxidation (PEO) treatments have been used in the aerospace and automotive industries because the coating formed on light metals or alloys has great hardness, high wear, corrosion, and oxidation resistance, and a low friction coefficient that improves lifetime length and provide a higher surface quality. However, the PEO treatments that are presently used for industrial applications require a long period of time to confirm the quality of the coating. For this reason, the present study seeks to increase the current density of PEO treatments to improve their efficiency and explore the performance of the obtained coatings. It was found that for high current density (0.18A/cm2) PEO treatments, smaller ratio, such as 50% and 70%, is beneficial to obtaining a better performance coating. When compared with the coating of a "normal" (current density: 0.09A/cm2) PEO treatment, it had better wear resistance; however, for corrosion resistance, it had a lower performance than the coatings obtained by the "normal" current density PEO treatment which was attributed to the negative influence of porosity increase.

  17. Effect of Nano-crystalline Ceramic Coats Produced by Plasma Electrolytic Oxidation on Corrosion Behavior of AA5083 Aluminum Alloy

    International Nuclear Information System (INIS)

    Thayananth, T.; Muthupandi, V.; Rao, S. R. Koteswara

    2010-01-01

    High specific strength offered by aluminum and magnesium alloys makes them desirable in modern transportation industries. Often the restrictions imposed on the usage of these alloys are due to their poor tribological and corrosion properties. However, their corrosion properties can be further enhanced by synthesizing ceramic coating on the substrate through Plasma Electrolytic Oxidation (PEO) process. In this study, nano-crystalline alumina coatings were formed on the surface of AA5083 aluminum alloy test coupons using PEO process in aqueous alkali-silicate electrolyte with and without addition of sodium aluminate. X-ray diffraction (XRD) studies showed that the crystallite size varied between 38 and 46 nm and α- and γ- alumina were the dominant phases present in the coatings. Corrosion studies by potentiodynamic polarization tests in 3.5% NaCl revealed that the electrolyte composition has an influence on the corrosion resistance of nano-crystalline oxide layer formed.

  18. Enhanced mechanical properties and increased corrosion resistance of a biodegradable magnesium alloy by plasma electrolytic oxidation (PEO)

    Energy Technology Data Exchange (ETDEWEB)

    White, Leon; Koo, Youngmi [FIT BEST Laboratory, Engineering Research Center, Department of Chemical, Biological, and Bio Engineering, North Carolina A& T State University, Greensboro, NC 27411 (United States); Neralla, Sudheer [Jet-Hot LLC, Burlington, NC 27215 (United States); Sankar, Jagannathan [FIT BEST Laboratory, Engineering Research Center, Department of Chemical, Biological, and Bio Engineering, North Carolina A& T State University, Greensboro, NC 27411 (United States); Yun, Yeoheung, E-mail: yyun@ncat.edu [FIT BEST Laboratory, Engineering Research Center, Department of Chemical, Biological, and Bio Engineering, North Carolina A& T State University, Greensboro, NC 27411 (United States)

    2016-06-15

    Highlights: • Plasma electrolytic oxidation (PEO) method was developed to control corrosion, porosity, and mechanical property. • Mechanical properties of PEO-coated AZ31 alloys were affected by the different electrolyte. • Mechanical properties and corrosion resistance of PEO-coated AZ31 alloys were compared with uncoated one. - Abstract: We report the enhanced mechanical properties of AZ31 magnesium alloys by plasma electrolytic oxidation (PEO) coating in NaOH, Na{sub 2}SiO{sub 3}, KF and NaH{sub 2}PO{sub 4}·2H{sub 2}O containing electrolytes. Mechanical properties including wear resistance, surface hardness and elastic modulus were increased for PEO-coated AZ31 Mg alloys (PEO-AZ31). DC polarization in Hank's solution indicating that the corrosion resistance significantly increased for PEO-coating in KF-contained electrolyte. Based on these results, the PEO coating method shows promising potential for use in biodegradable implant applications where tunable corrosion and mechanical properties are needed.

  19. Effect of DC Plasma Electrolytic Oxidation on Surface Characteristics and Corrosion Resistance of Zirconium

    Directory of Open Access Journals (Sweden)

    Maciej Sowa

    2018-05-01

    Full Text Available Zr is a valve metal, the biocompatibility of which is at least on par with Ti. Recently, numerous attempts of the formation of bioactive coatings on Zr by plasma electrolytic oxidation (PEO in solutions that were based on calcium acetate and calcium β-glycerophosphate were made. In this study, the direct current (DC PEO of commercially pure zirconium in the solutions that contained Ca(H2PO22, Ca(HCOO2, and Mg(CH3COO2 was investigated. The treatment was conducted at 75 mA/cm2 up to 200, 300, or 400 V. Five process stages were discerned. The treatment at higher voltages resulted in the formation of oxide layers that had Ca/P or (Mg+Ca/P ratios that were close to that of hydroxyapatite (Ca/P = 1.67, determined by SEM/EDX. The corrosion resistance studies were performed using electrochemical impedance spectroscopy (EIS and DC polarization methods. R(Q[R(QR] circuit model was used to fit the EIS data. In general, the coatings that were obtained at 200 V were the most corrosion resistant, however, they lacked the porous structure, which is typical for PEO coatings, and is sought after in the biomedical applications. The treatment at 400 V resulted in the formation of the coatings that were more corrosion resistant than those that were obtained at 300 V. This was determined mainly by the prevailing plasma regime at the given process voltage. The pitting resistance of Zr was also improved by the treatment, regardless of the applied process conditions.

  20. Plasma electrolytic oxidation of AZ91D magnesium alloy with different additives and its corrosion behavior

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Fa-he; Cao, Jiang-lin; Zhang, Zhao [Department of Chemistry, Zhejiang University, Hangzhou 310027 (China); Zhang, Jian-qing; Cao, Chu-nan [Department of Chemistry, Zhejiang University, Hangzhou 310027 (China); State Key Laboratory for Corrosion and Protection, Institute of Metal Research, The Chinese Academy of Sciences, Shenyang 110016 (China)

    2007-09-15

    Plasma electrolytic oxidation (PEO) of Mg-based AZ91D alloys was investigated using 50 Hz AC anodizing technique in an alkaline borate solution, which contained a new kind of organic additive and without F, P, and Cr. The anodizing technological parameters have been optimized and a kind of ivory-white smooth anodic film with high corrosion resistance was obtained. It was found that the formation of the anodic films was always coupled with sparking and oxygen evolution, whose intensity changed with the additive and anodizing voltage. All EIS plots have two capacitive loops and one low frequency inductive component. Two capacitive arcs present the barrier and porous layer of the PEO film and the inductive component in the low frequency domain is a complex behavior due to the porous structure connected to the electrolyte. EIS plots and fitting results show that a self-sealing process of the PEO firm with different additives takes place in the beginning of immersion time, then corrosion attack becomes a preponderant process to promote the degradation of the film. Tafel results show that PEO treatment decreases the corrosion current density by four, even five orders of magnitude, while additives content does not affect strongly the electrochemical corrosion behavior. Salt spray test shows that the PEO film formed with NaAlO{sub 2} and Na{sub 2}SiO{sub 3} presents good corrosion resistance, over 600 h without any sealing treatment. The difference of corrosion resistance arose by additives examined by electrochemical techniques and salt spray test does not show strict corresponding relationship. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  1. XPS and GDOES Characterization of Porous Coating Enriched with Copper and Calcium Obtained on Tantalum via Plasma Electrolytic Oxidation

    Directory of Open Access Journals (Sweden)

    Krzysztof Rokosz

    2016-01-01

    Full Text Available XPS and GDOES characterizations of porous coatings on tantalum after Plasma Electrolytic Oxidation (PEO at 450 V for 3 minutes in electrolyte containing concentrated (85% phosphoric acid with calcium nitrate and copper (II nitrate are described. Based on the obtained data, it may be concluded that the PEO coating consists of tantalum (Ta5+, calcium (Ca2+, copper (Cu2+  and Cu+, and phosphates (PO43-. It has to be pointed out that copper and calcium are distributed throughout the volume. The authors also propose a new model of PEO, based on the derivative of GDOES signals with sputtering time.

  2. Electrochemical and biological characterization of coatings formed on Ti-15Mo alloy by plasma electrolytic oxidation.

    Science.gov (United States)

    Kazek-Kęsik, Alicja; Krok-Borkowicz, Małgorzata; Pamuła, Elżbieta; Simka, Wojciech

    2014-10-01

    β-Type titanium alloys are considered the future materials for bone implants. To improve the bioactivity of Ti-15Mo, the surface was modified using the plasma electrolytic oxidation (PEO) process. Tricalcium phosphate (TCP, Ca3PO4), wollastonite (CaSiO3) and silica (SiO2) were selected as additives in the anodizing bath to enhance the bioactivity of the coatings formed during the PEO process. Electrochemical analysis of the samples was performed in Ringer's solution at 37°C. The open-circuit potential (EOCP) as a function of time, corrosion potential (ECORR), corrosion current density (jCORR) and polarization resistance (Rp) of the samples were determined. Surface modification improved the corrosion resistance of Ti-15Mo in Ringer's solution. In vitro studies with MG-63 osteoblast-like cells were performed for 1, 3 and 7 days. After 24h, the cells were well adhered on the entire surfaces, and their number increased with increasing culture time. The coatings formed in basic solution with wollastonite exhibited better biological performance compared with the as-ground sample. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Electrochemical Impedance and Polarization Corrosion Studies of Tantalum Surface Modified by DC Plasma Electrolytic Oxidation

    Directory of Open Access Journals (Sweden)

    Maciej Sowa

    2018-04-01

    Full Text Available Tantalum has recently become an actively researched biomaterial for the bone reconstruction applications because of its excellent corrosion resistance and successful clinical records. However, a bare Ta surface is not capable of directly bonding to the bone upon implantation and requires some method of bioactivation. In this study, this was realized by direct current (DC plasma electrolytic oxidation (PEO. Susceptibility to corrosion is a major factor determining the service-life of an implant. Therefore, herein, the corrosion resistance of the PEO coatings on Ta was investigated in Ringer’s solution. The coatings were formed by galvanostatic anodization up to 200, 300 and 400 V, after which the treatment was conducted potentiostatically until the total process time amounted to 5 min. Three solutions containing Ca(H2PO22, Ca(HCOO2 and Mg(CH3COO2 were used in the treatment. For the corrosion characterization, electrochemical impedance spectroscopy and potentiodynamic polarization techniques were chosen. The coatings showed the best corrosion resistance at voltages low enough so that the intensive sparking was absent, which resulted in the formation of thin films. The impedance data were fitted to the equivalent electrical circuits with two time constants, namely R(Q[R(QR] and R(Q[R(Q[RW

  4. Plasma Electrolytic Oxidation of Titanium Implant Surfaces: Microgroove-Structures Improve Cellular Adhesion and Viability.

    Science.gov (United States)

    Hartjen, Philip; Hoffmann, Alexia; Henningsen, Anders; Barbeck, Mike; Kopp, Alexander; Kluwe, Lan; Precht, Clarissa; Quatela, Olivia; Gaudin, Robert; Heiland, Max; Friedrich, Reinhard E; Knipfer, Christian; Grubeanu, Daniel; Smeets, Ralf; Jung, Ole

    2018-01-01

    Plasma electrolytic oxidation (PEO) is an established electrochemical treatment technique that can be used for surface modifications of metal implants. In this study we to treated titanium implants with PEO, to examine the resulting microstructure and to characterize adhesion and viability of cells on the treated surfaces. Our aim was to identify an optimal surface-modification for titanium implants in order to improve soft-tissue integration. Three surface-variants were generated on titanium alloy Ti6Al4V by PEO-treatment. The elemental composition and the microstructures of the surfaces were characterized using energy dispersive X-ray spectroscopy, scanning electron microscopy and profilometry. In vitro cytocompatibility of the surfaces was assessed by seeding L929 fibroblasts onto them and measuring the adhesion, viability and cytotoxicity of cells by means of live/dead staining, XTT assay and LDH assay. Electron microscopy and profilometry revealed that the PEO-surface variants differed largely in microstructure/topography, porosity and roughness from the untreated control material as well as from one another. Roughness was generally increased after PEO-treatment. In vitro, PEO-treatment led to improved cellular adhesion and viability of cells accompanied by decreased cytotoxicity. PEO-treatment provides a promising strategy to improve the integration of titanium implants with surrounding tissues. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  5. Corrosion and nanomechanical behaviors of plasma electrolytic oxidation coated AA7020-T6 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Venugopal, A., E-mail: arjun_venu@hotmail.com [Materials and Metallurgy Group, Materials and Mechanical Entity, Vikram Sarabhai Space Centre, Thiruvananthapuram (India); Srinath, J. [Materials and Metallurgy Group, Materials and Mechanical Entity, Vikram Sarabhai Space Centre, Thiruvananthapuram (India); Rama Krishna, L. [International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Balapur P.O., Hyderabad 500005 (India); Ramesh Narayanan, P.; Sharma, S.C.; Venkitakrishnan, P.V. [Materials and Metallurgy Group, Materials and Mechanical Entity, Vikram Sarabhai Space Centre, Thiruvananthapuram (India)

    2016-04-13

    Alumina coating was deposited on AA7020 aluminum alloy by plasma electrolytic oxidation (PEO) method. The corrosion, stress corrosion cracking (SCC) and nano-mechanical behaviors were examined by means of potentiodynamic polarization, slow strain rate test (SSRT) and nano-indentation tests. Potentiodynamic polarization (PP) was used to evaluate the corrosion resistance of the coating and slow strain rate test (SSRT) was used for evaluating the environmental cracking resistance in 3.5% NaCl solution. The mechanical properties (hardness and elastic modulus) were obtained from each indentation as a function of the penetration depth across the coating cross section. The above results were compared with similar PEO coated aluminum and magnesium alloys. Results indicated that PEO coating on AA7020 alloy significantly improved the corrosion resistance. However the environmental cracking resistance was found to be only marginal. The hardness and elastic modulus values were found to be much higher when compared to the base metal and similar PEO coated 7075 aluminum alloys. The fabricated coating also exhibited good adhesive strength with the substrate similar to other PEO coated aluminum alloys reported in the literature.

  6. Characterization and formation of hydroxyapatite on Ti6Al4V coated by plasma electrolytic oxidation

    International Nuclear Information System (INIS)

    Durdu, Salih; Deniz, Ömer Faruk; Kutbay, Işıl; Usta, Metin

    2013-01-01

    Highlights: ► Ti6Al4V alloys were coated by PEO in calcium acetate and β-calcium glycerophosphate. ► Hydroxyapatite and calcium apatite based phases were directly formed on Ti6Al4V. ► Hydroxyapatite coatings were characterized systematically for different times. ► After 5 min, hydroxyapatite and calcium based phases begin to form on the coating. ► HAp on the coating is amorphous due to the rapid solidification during PEO. - Abstract: In this study, Ti6Al4V alloy was coated in the solution consisting of calcium acetate (CA) and β-calcium glycerophosphate (β-Ca-GP) by plasma electrolytic oxidation (PEO) to produce hydroxyapatite and calcium apatite-based composite used as of bioactive and biocompatible materials in biomedical applications. The phase structures, surface morphologies, functional groups of molecules, chemical compositions of the surfaces and the binding energies of atoms in the coating were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS), respectively. Anatase, rutile, calcium oxide, titanium phosphide, whitlockite, tri-calcium phosphate (TCP), perovskite calcium titanate and hydroxyapatite phases on the coating were detected by XRD analysis. The surface of coatings produced by PEO method has a porous structure. The amount of amorphous hydroxyapatite is the highest value for the coating produced at 5 min in XPS and ATR-FTIR results, whereas the amount of crystalline hydroxyapatite has the highest value for coating produced at 120 min in XRD results.

  7. Bioactivity and biocompatibility of hydroxyapatite-based bioceramic coatings on zirconium by plasma electrolytic oxidation.

    Science.gov (United States)

    Aktuğ, Salim Levent; Durdu, Salih; Yalçın, Emine; Çavuşoğlu, Kültigin; Usta, Metin

    2017-02-01

    In the present work, hydroxyapatite (HAP)-based plasma electrolytic oxide (PEO) coatings were produced on zirconium at different current densities in a solution containing calcium acetate and β-calcium glycerophosphate by a single step. The phase structure, surface morphology, functional groups, thickness and roughness of the coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), eddy current method and surface profilometer, respectively. The phases of cubic-zirconia, calcium zirconate and HAP were detected by XRD. The amount of HAP and calcium zirconate increased with increasing current density. The surface of the coatings was very porous and rough. Moreover, bioactivity and biocompatibility of the coatings were analyzed in vitro immersion simulated body fluid (SBF) and MTT (3-(4,5-dimethyl thiazol-2yl)-2,5-diphenyl tetrazolium bromide) assay, hemolysis assay and bacterial formation. The apatite-forming ability of the coatings was evaluated after immersion in SBF up to 28days. After immersion, the bioactivity of HAP-based coatings on zirconium was greater than the ones of uncoated zirconium and zirconium oxide-based surface. The bioactivity of PEO surface on zirconium was significantly improved under SBF conditions. The bacterial adhesion of the coatings decreased with increasing current density. The bacterial adhesion of the coating produced at 0.370A/cm 2 was minimum compared to uncoated zirconium coated at 0.260 and 0.292A/cm 2 . The hemocompatibility of HAP-based surfaces was improved by PEO. The cell attachment and proliferation of the PEO coatings were better than the one of uncoated zirconium according to MTT assay results. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Preparation of ceramic coating on Ti substrate by Plasma electrolytic oxidation in different electrolytes and evaluation of its corrosion resistance

    Science.gov (United States)

    Shokouhfar, M.; Dehghanian, C.; Baradaran, A.

    2011-01-01

    Ceramic oxide coatings (titania) were produced on Ti by micro-arc oxidation in different aluminate and carbonate based electrolytes. This process was conducted under constant pulsed DC voltage condition. The effect of KOH and NaF in aluminate based solution was also studied. The surface morphology, growth and phase composition of coatings were investigated using scanning electron microscope and X-ray diffraction. Corrosion behavior of the coatings was also examined by potentiodynamic polarization and electrochemical impedance spectroscopy. It was found that the sparking initiation voltage (spark voltage) had a significant effect on the form and properties of coatings. Coatings obtained from potassium aluminate based solution had a lower spark voltage, higher surface homogeneity and a better corrosion resistance than the carbonate based solution. Addition of NaF instead of KOH had improper effects on the homogeneity and adhesion of coatings which in turn caused a poor corrosion protection behavior of the oxide layer. AC impedance curves showed two time constants which is an indication of the coatings with an outer porous layer and an inner compact layer.

  9. In situ fabrication of blue ceramic coatings on wrought Al Alloy 2024 by plasma electrolytic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Wang Zhijiang; Nie Xueyuan; Hu, Henry; Hussein, Riyad O. [Department of Mechanical, Automotive and Materials Engineering, University of Windsor, Windsor, Ontario N9B 3P4 (Canada)

    2012-03-15

    In situ formation of ceramic coatings on 2024 Al alloy with a blue color was successfully achieved using a plasma electrolytic oxidation process working at atmospheric pressure. This novel blue ceramic coating overcomes the shortcomings of surface treatments resulting from conventional dyeing processes by depositing organic dyes into the porous structure of anodic film, which has poor resistance to abrasion and rapid fading when exposed to sunlight. X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy were employed to characterize the microstructure of the blue ceramic coating. The fabricated ceramic coating was composed of CoAl{sub 2}O{sub 4}, {alpha}-Al{sub 2}O{sub 3}, and {gamma}-Al{sub 2}O{sub 3.} By controlling the working parameters, the distribution of the CoAl{sub 2}O{sub 4} phase on the surface can be adjusted, and plays a key role in the appearance of the coating. Electrochemical testing, thermal cycling method, and pin-on-disk sliding wear testing were employed to evaluate corrosion, thermal cycling, and wear resistance of the ceramic coatings. The results indicate that the blue ceramic coating has a similar polarization resistance to that of conventional anodic film and can significantly enhance the corrosion resistance of aluminum alloy. There are no destructive horizontal cracks observed within the blue ceramic coating when subjected to 120 times of thermal cycling, which heats the samples up to 573 K and followed by submersion in water at room temperature for 10 min. Compared with the aluminum substrate as well as a conventional anodic film coated aluminum sample, the wear resistance of the blue ceramic coating coated sample was significantly increased while the coefficient of friction was decreased from 0.34 to 0.14.

  10. Osseointegration improvement by plasma electrolytic oxidation of modified titanium alloys surfaces.

    Science.gov (United States)

    Echeverry-Rendón, Mónica; Galvis, Oscar; Quintero Giraldo, David; Pavón, Juan; López-Lacomba, José Luis; Jiménez-Piqué, Emilio; Anglada, Marc; Robledo, Sara M; Castaño, Juan G; Echeverría, Félix

    2015-02-01

    Titanium (Ti) is a material frequently used in orthopedic applications, due to its good mechanical properties and high corrosion resistance. However, formation of a non-adherent fibrous tissue between material and bone drastically could affect the osseointegration process and, therefore, the mechanical stability of the implant. Modifications of topography and configuration of the tissue/material interface is one of the mechanisms to improve that process by manipulating parameters such as morphology and roughness. There are different techniques that can be used to modify the titanium surface; plasma electrolytic oxidation (PEO) is one of those alternatives, which consists of obtaining porous anodic coatings by controlling parameters such as voltage, current, anodizing solution and time of the reaction. From all of the above factors, and based on previous studies that demonstrated that bone cells sense substrates features to grow new tissue, in this work commercially pure Ti (c.p Ti) and Ti6Al4V alloy samples were modified at their surface by PEO in different anodizing solutions composed of H2SO4 and H3PO4 mixtures. Treated surfaces were characterized and used as platforms to grow osteoblasts; subsequently, cell behavior parameters like adhesion, proliferation and differentiation were also studied. Although the results showed no significant differences in proliferation, differentiation and cell biological activity, overall results showed an important influence of topography of the modified surfaces compared with polished untreated surfaces. Finally, this study offers an alternative protocol to modify surfaces of Ti and their alloys in a controlled and reproducible way in which biocompatibility of the material is not compromised and osseointegration would be improved.

  11. In situ fabrication of blue ceramic coatings on wrought Al Alloy 2024 by plasma electrolytic oxidation

    International Nuclear Information System (INIS)

    Wang Zhijiang; Nie Xueyuan; Hu, Henry; Hussein, Riyad O.

    2012-01-01

    In situ formation of ceramic coatings on 2024 Al alloy with a blue color was successfully achieved using a plasma electrolytic oxidation process working at atmospheric pressure. This novel blue ceramic coating overcomes the shortcomings of surface treatments resulting from conventional dyeing processes by depositing organic dyes into the porous structure of anodic film, which has poor resistance to abrasion and rapid fading when exposed to sunlight. X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy were employed to characterize the microstructure of the blue ceramic coating. The fabricated ceramic coating was composed of CoAl 2 O 4 , α-Al 2 O 3 , and γ-Al 2 O 3. By controlling the working parameters, the distribution of the CoAl 2 O 4 phase on the surface can be adjusted, and plays a key role in the appearance of the coating. Electrochemical testing, thermal cycling method, and pin-on-disk sliding wear testing were employed to evaluate corrosion, thermal cycling, and wear resistance of the ceramic coatings. The results indicate that the blue ceramic coating has a similar polarization resistance to that of conventional anodic film and can significantly enhance the corrosion resistance of aluminum alloy. There are no destructive horizontal cracks observed within the blue ceramic coating when subjected to 120 times of thermal cycling, which heats the samples up to 573 K and followed by submersion in water at room temperature for 10 min. Compared with the aluminum substrate as well as a conventional anodic film coated aluminum sample, the wear resistance of the blue ceramic coating coated sample was significantly increased while the coefficient of friction was decreased from 0.34 to 0.14.

  12. Characterization of metal-supported axial injection plasma sprayed solid oxide fuel cells with aqueous suspension plasma sprayed electrolyte layers

    Science.gov (United States)

    Waldbillig, D.; Kesler, O.

    A method for manufacturing metal-supported SOFCs with atmospheric plasma spraying (APS) is presented, making use of aqueous suspension feedstock for the electrolyte layer and dry powder feedstock for the anode and cathode layers. The cathode layer was deposited first directly onto a metal support, in order to minimize contact resistance, and to allow the introduction of added porosity. The electrolyte layers produced by suspension plasma spraying (SPS) were characterized in terms of thickness, permeability, and microstructure, and the impact of substrate morphology on electrolyte properties was investigated. Fuel cells produced by APS were electrochemically tested at temperatures ranging from 650 to 750 °C. The substrate morphology had little effect on open circuit voltage, but substrates with finer porosity resulted in lower kinetic losses in the fuel cell polarization.

  13. Characterization of metal-supported axial injection plasma sprayed solid oxide fuel cells with aqueous suspension plasma sprayed electrolyte layers

    Energy Technology Data Exchange (ETDEWEB)

    Waldbillig, D. [University of British Columbia, Department of Materials Engineering, 309-6350 Stores Road, Vancouver, BC (Canada); Kesler, O. [University of Toronto, Department of Mechanical and Industrial Engineering, 5 King' s College Road, Toronto, Ontario (Canada)

    2009-06-15

    A method for manufacturing metal-supported SOFCs with atmospheric plasma spraying (APS) is presented, making use of aqueous suspension feedstock for the electrolyte layer and dry powder feedstock for the anode and cathode layers. The cathode layer was deposited first directly onto a metal support, in order to minimize contact resistance, and to allow the introduction of added porosity. The electrolyte layers produced by suspension plasma spraying (SPS) were characterized in terms of thickness, permeability, and microstructure, and the impact of substrate morphology on electrolyte properties was investigated. Fuel cells produced by APS were electrochemically tested at temperatures ranging from 650 to 750 C. The substrate morphology had little effect on open circuit voltage, but substrates with finer porosity resulted in lower kinetic losses in the fuel cell polarization. (author)

  14. Influence of the reuse of the electrolytic solution on the properties of hydroxyapatite coatings produced by plasma electrolytic oxidation of grade 4 titanium

    Energy Technology Data Exchange (ETDEWEB)

    Antonio, Cesar A.; Rangel, Elidiane Cipriano; Cruz, Nilson Cristino, E-mail: cesar.augustoa@hotmail.com [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sorocaba, SP (Brazil)

    2016-07-01

    Full text: Plasma electrolytic oxidation (PEO) is a process able to produce oxide coatings on light metals, such as Al, Ti, V, Mg, Ta and Nb. In this technique, the application of a voltage, in the range of hundreds of volts, between the sample and a cathode immersed in an electrolyte solution produces electrical fields intense enough to breakdown the insulating oxide layer on the sample surface giving rise to micro electric sparks[1]. These micro-arcs can locally melt the substrate alloying it with elements in the electrolyte solution [2]. In this work PEO has been used to produce coatings with high concentration of hydroxyapatite on Grade 4 titanium disks. The treatments were performed in a 1 liter stainless steel tank. The tank wall was used as the cathode and the coatings were produced during 120 s using calcium acetate and sodium glycerophosphate water solutions as electrolyte. The samples were biased with 480 V pulses with frequency and duty cycle of 100 Hz and 60%, respectively. Using profilometry, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction it has been evaluated the influence of the number of reuses of the solution on the coating properties. The coating produced contains around 85% of HA and it has not been observed any significant changes in their properties when the same solution was reused up to 5 times. [1] A.L. Yerokhin, X. Nie, A. Leyland, A. Matthews, Surf. Coat. Technol. 130 (2000) 195 206. [2] C. A. Antonio, N. C. Cruz, et al. Materials Research. 17(6) 2014; 1427-1433. (author)

  15. Effect of additive on electrochemical corrosion properties of plasma electrolytic oxidation coatings formed on CP Ti under different processing frequency

    Energy Technology Data Exchange (ETDEWEB)

    Babaei, Mahdi, E-mail: mahdi.babaei@ut.ac.ir; Dehghanian, Changiz; Vanaki, Mojtaba

    2015-12-01

    Highlights: • PEO coatings formed on Cp Ti from phosphate electrolyte with zirconate additive. • The SEM results provide information of microdischarge behavior. • The effect of additive on structure and long-term corrosion behavior was investigated. • The additive influence on coating performance varies with processing frequency. - Abstract: The plasma electrolytic oxidation (PEO) coating containing zirconium oxide was fabricated on CP Ti at different processing frequencies viz., 100 Hz and 1000 Hz in a (Na{sub 2}ZrO{sub 3}, Na{sub 2}SiO{sub 3})-additive containing NaH{sub 2}PO{sub 4}-based solution, and long-term electrochemical corrosion behavior of the coatings was studied using electrochemical impedance spectroscopy (EIS) in 3.5 wt.% NaCl solution. Electrochemical degradation behavior of two-layered coatings formed at different frequencies was turned out to be governed by concentration of electrolyte additive. With increasing additive concentration, the coating obtained at frequency of 1000 Hz exhibited enhanced corrosion resistance. However, corrosion resistance of the coating prepared at 100 Hz was found to decrease with increased additive, which was attributed to intensified microdischarges damaging the protective effect of inner layer. Nevertheless, the electrolyte additive was found to mitigate the long-term degradation of the coatings to a significant extent.

  16. A Simple Method to Functionalize the Surface of Plasma Electrolytic Oxidation Produced TiO2 Coatings for Growing Hydroxyapatite

    International Nuclear Information System (INIS)

    Teng, Huan-Ping; Yang, Chia-Jung; Lin, Jia-Fu; Huang, Yu-Hsin; Lu, Fu-Hsing

    2016-01-01

    Highlights: • TiO 2 coatings with porous surfaces were produced by plasma electrolytic oxidation. • Simple pre-immersion in K 2 HPO 4 could functionalize the surfaces of the TiO 2 . • Such pre-immersion enhanced substantially the growth of hydroxyapatite in SBF. • Growth mechanisms of hydroxyapatite via the pre-immersion have been proposed. • MTT assay shows great osteoblast-like cell activity on the obtained hydroxyapatite. - Abstract: Conventionally, hydrothermal treatment was often used to modify the TiO 2 surface prior to the growth of hydroxyapatite (HA) that is one of the most important implant biomaterials. In this work, a simple pre-immersion of the obtained TiO 2 in a weak base, instead of the conventionally high pressure-temperature hydrothermal pre-treatment, was conducted prior to the growth of HA. Firstly, anatase TiO 2 coatings with porous surfaces were produced by plasma electrolytic oxidation with optimized processing parameters. X-ray diffraction patterns and field-emission microscopy reveal that the anatase TiO 2 films with porous surfaces were produced by plasma electrolytic oxidation. Subsequently, the films were pre-immersed in 0.1–2 M K 2 HPO 4 solutions for only 10 min. Fourier transform infrared spectroscopy shows that the −OH functional groups were generated after such pre-immersion, which could enhance significantly the growth of a single phase of HA in simulated body fluid (SBF). Growth mechanisms of HA via the pre-immersion treatment and soaking in SBF have been proposed. Moreover, the proliferation rate and attachment of the MG-63 osteoblast cells were greatly enhanced on the obtained HA compared to that without the immersion pre-treatment from the MTT assay and morphology analyses. This simple immersion pre-treatment evidently provides an easy route for the growth of HA and has great potential for biomedical applications.

  17. Surface Charge at the Oxide/Electrolyte Interface: Toward Optimization of Electrolyte Composition for Treatment of Aluminum and Magnesium by Plasma Electrolytic Oxidation

    Czech Academy of Sciences Publication Activity Database

    Nominé, A.; Martin, J.; Noël, C.; Henrion, G.; Belmonte, T.; Bardin, I.V.; Lukeš, Petr

    2016-01-01

    Roč. 32, č. 5 (2016), s. 1405-1409 ISSN 0743-7463 Institutional support: RVO:61389021 Keywords : corrosion-resistance * Mg-alloy * cotings * layers * microstructure * porosity * points Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.833, year: 2016

  18. Effects of concentration of Ag nanoparticles on surface structure and in vitro biological responses of oxide layer on pure titanium via plasma electrolytic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Ki Ryong; Kim, Yeon Sung; Kim, Gye Won [Department of Materials Science and Engineering, Hanyang University, Ansan 425-791 (Korea, Republic of); Yang, Hae Woong [School of Materials Science and Engineering, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Ko, Young Gun, E-mail: younggun@ynu.ac.kr [School of Materials Science and Engineering, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Shin, Dong Hyuk, E-mail: dhshin@hanyang.ac.kr [Department of Materials Science and Engineering, Hanyang University, Ansan 425-791 (Korea, Republic of)

    2015-08-30

    Highlights: • Ag nanoparticles were embedded into the oxide surface without any compositional changes. • Oxide layer from the electrolyte with 0.1 g/l Ag nanoparticles could disinfect all bacteria. • With increasing Ag nanoparticles, bone-forming ability and cell proliferation rate decrease. - Abstract: This study was to investigate how Ag nanoparticles with various concentrations affect the surface structure and in vitro biological properties of oxide layers on the pure titanium produced by a plasma electrolytic oxidation (PEO) process. For this aim, PEO processes were carried out at an AC current density of 100 mA/cm{sup 2} for 300 s in potassium pyrophosphate (K{sub 4}P{sub 2}O{sub 7}) electrolytes containing 0, 0.1, 0.3 and 0.5 g/l Ag nanoparticles. Structural investigations using scanning electron microscopy evidenced that the oxide layers showed the successful incorporation of Ag nanoparticles, and the topographical deformation of the porous surface was found when the concentration of Ag nanoparticles was more than 0.1 g/l. Based on the anti-bacterial activity of all oxide layers, the Ag nanoparticles uniformly spread were of considerable importance in triggering the disinfection of E. coli bacteria. The bone forming abilities and cell (MC3T3-E1) proliferation rates of oxide layers produced in electrolytes containing 0 and 0.1 g/l Ag nanoparticles were higher than those containing 0.3 and 0.5 g/l Ag nanoparticles. Consequently, the oxide layer on pure titanium via PEO process in the electrolyte with 0.1 g/l Ag nanoparticles exhibited better the bioactivity accompanying the anti-bacterial activity.

  19. A spectroscopic and microstructural study of oxide coatings produced on a Ti–6Al–4V alloy by plasma electrolytic oxidation

    International Nuclear Information System (INIS)

    Hussein, R.O.; Nie, X.; Northwood, D.O.

    2012-01-01

    Highlights: ► PEO (plasma electrolytic oxidation) for production of oxide coatings on a Ti–6Al–4V alloy. ► Two different current modes namely pulsed unipolar and bipolar was used. ► Optical emission spectroscopy (OES) was used to characterize the PEO plasma. ► This is the first attempt to characterize spectroscopically the PEO plasma of Ti and its alloys. ► The discharge behavior effect on the formation and structure of the coating was determined. - Abstract: In this study, we have used PEO (plasma electrolytic oxidation) for the production of oxide coatings on a Ti–6Al–4V alloy at two different current modes, namely pulsed unipolar and bipolar. Optical emission spectroscopy (OES) in the visible and near UV band (280–800 nm) was used to characterize the PEO plasma. The emission spectra were recorded and the plasma temperature profile versus processing time was constructed using a line intensity ratios method. The aim of this work was to study the effect of the process parameters, including current mode and pulse duration time, on the plasma characteristics, surface morphology and microstructure and corrosion resistance of oxides grown on Ti–6Al–4V by PEO process. Scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDS) and X-ray diffraction (XRD) were used to study the coating microstructure, morphology and phase composition. The corrosion resistance of the coated and uncoated samples was examined by potentiodynamic polarization in a 3.5% NaCl solution. It was found that the plasma temperature profiles are significantly influenced by changing the current mode from unipolar to bipolar. The strongest discharges that are initiated at the interface between the substrate and the coating can be reduced or eliminated by using a bipolar current mode. This produces a thinner, denser and more corrosion-resistant coating.

  20. Electrochemical performance of solid oxide fuel cells having electrolytes made by suspension and solution precursor plasma spraying

    Science.gov (United States)

    Marr, M.; Kuhn, J.; Metcalfe, C.; Harris, J.; Kesler, O.

    2014-01-01

    Yttria-stabilized zirconia (YSZ) electrolytes were deposited by suspension plasma spraying (SPS) and solution precursor plasma spraying (SPPS). The electrolytes were evaluated for permeability, microstructure, and electrochemical performance. With SPS, three different suspensions were tested to explore the influence of powder size distribution and liquid properties. Electrolytes made from suspensions of a powder with d50 = 2.6 μm were more gas-tight than those made from suspensions of a powder with d50 = 0.6 μm. A peak open circuit voltage of 1.00 V was measured at 750 °C with a cell with an electrolyte made from a suspension of d50 = 2.6 μm powder. The use of a flammable suspension liquid was beneficial for improving electrolyte conductivity when using lower energy plasmas, but the choice of liquid was less important when using higher energy plasmas. With SPPS, peak electrolyte conductivities were comparable to the peak conductivities of the SPS electrolytes. However, leak rates through the SPPS electrolytes were higher than those through the electrolytes made from suspensions of d50 = 2.6 μm powder. The electrochemical test data on SPPS electrolytes are the first reported in the literature.

  1. Evolution processes of the corrosion behavior and structural characteristics of plasma electrolytic oxidation coatings on AZ31 magnesium alloy

    Science.gov (United States)

    Chen, Dong; Wang, Ruiqiang; Huang, Zhiquan; Wu, Yekang; Zhang, Yi; Wu, Guorui; Li, Dalong; Guo, Changhong; Jiang, Guirong; Yu, Shengxue; Shen, Dejiu; Nash, Philip

    2018-03-01

    Evolution processes of the corrosion behavior and structural characteristics of the plasma electrolytic oxidation (PEO) coated AZ31 magnesium alloy were investigated by using scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), potentio-dynamic polarization curves and electrochemical impedance spectroscopy (EIS) measurements. Detached coating samples were fabricated by an electrochemical method and more details of the internal micro-structure of coatings were clearly observed on the fractured cross-section morphologies of the samples compared to general polished cross-section morphologies. Evolution mechanisms of the coating corrosion behavior in relation to the evolution of micro-structural characteristics were discussed in detail.

  2. Effects of cathode pulse at low frequency on the structure and composition of plasma electrolytic oxidation ceramic coatings

    International Nuclear Information System (INIS)

    Yao Zhongping; Xu Yongjun; Jiang Zhaohua; Wang Fuping

    2009-01-01

    The aim of this work is to investigate the effects of the cathode pulse under the low working frequency on the structure and the composition of the ceramic coatings on Ti-6Al-4V alloys by plasma electrolytic oxidation (PEO). Ceramic coatings were prepared on Ti alloy by pulsed bi-polar plasma electrolytic oxidation in NaAlO 2 solution. The phase composition, morphology, and element distribution in the coating were investigated by X-ray diffractometry, scanning electron microscopy, and energy distribution spectroscopy. The coating was mainly composed of a large amount of Al 2 TiO 5 and a little α-Al 2 O 3 and rutile TiO 2 . Increasing the cathode pulse, the amount of rutile TiO 2 was increased while the amount of Al 2 O 3 was decreased; and decreasing the cathode pulse, the amount of Al 2 O 3 was increased while the amount of rutile TiO 2 was decreased. The thickness of the coatings was increased and then decreased with the increase of the cathode pulse. The grain sizes of Al 2 TiO 5 were increased with the cathode current densities, but changed little with the cathode pulse width. The grain size of α-Al 2 O 3 was decreased with the decrease of the cathode pulse, while the grain size of TiO 2 was increased with the increase of the cathode pulse. The proper cathode pulse was helpful to reduce the roughness and to increase the density of the coatings.

  3. Formation of Ca/P ceramic coatings by Plasma Electrolytic Oxidation (PEO) on Ti6Al4V ELI alloy

    Science.gov (United States)

    Rodriguez-Jaimes, Y.; Naranjo, D. I.; Blanco, S.; García-Vergara, S. J.

    2017-12-01

    The formation of PEO ceramic coatings on Ti6Al4V ELI alloy was investigated using a phosphate/calcium containing electrolyte at 300 and 400V at 310K for different times. The Plasma Electrolytic Oxidation (PEO) coated specimens were then heat treated at 873 and 1073K for 2 hours. Scanning electron microscopy, Energy Dispersive X-Ray Spectroscopy (EDS) and X-ray diffraction analysis were used to study the composition and the morphology of the ceramic coatings. The corrosion behaviour of the coatings was studied by Electrochemical Impedance Spectroscopy (EIS) in Simulated Body Fluid (SBF). The PEO-treated specimens primarily revealed a porous structure with thickness between 4 and 12μm, according to the voltage and process time used. The coatings are mainly composed of hydroxyapatite; however, as the voltage and anodizing time increase, the Ca/P ratio decreases. Generally, the corrosion resistance of the alloy was improved by the PEO-treated coatings, although the specimens treated at 1073K showed the presence of cracks that reduced the protective effect of the coatings.

  4. An electrochemical analysis of AZ91 Mg alloy processed by plasma electrolytic oxidation followed by static annealing

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Y.G. [School of Materials Science and Engineering, Yeungnam University, 214-1 Dae-Dong, Gyeongsan 712-749, Gyeongbuk (Korea, Republic of); Lee, K.M.; Lee, B.U. [Department of Metallurgy and Materials Engineering, Hanyang University, Ansan 425-791 (Korea, Republic of); Shin, D.H., E-mail: dhshin@hanyang.ac.kr [Department of Metallurgy and Materials Engineering, Hanyang University, Ansan 425-791 (Korea, Republic of)

    2011-06-15

    Research highlights: > The amount of MgO in the oxide film increased with increasing annealing temperature. > The dehydration reaction resulted in the formation of micro-cracks in the oxide film. > Electrochemical response of the PEO-treated sample annealed at 150 deg. C was improved. - Abstract: In this study, the effect of subsequent annealing on the electrochemical response of AZ91 Mg alloy coated via plasma electrolytic oxidation (PEO) was investigated. PEO coating was carried out on the Mg alloy under AC condition in an alkaline silicate electrolyte, and the PEO-coated samples underwent several subsequent annealing treatments at three different temperatures of 100, 150, and 200 deg. C. The surface morphologies of the coating layers were observed via a scanning electron microscope (SEM) and their constituent compounds were characterized by qualitative observation based on X-ray photoelectron spectroscopy (XPS). In addition, the corrosion protection properties of the PEO-coated sample were examined by electrochemical impedance spectroscopy (EIS) in a 3.5 wt% NaCl solution with a focus on exploring the effect of subsequent annealing on the electrochemical response in a quantitative manner. SEM and XPS observations evidenced that the subsequent annealing at temperatures higher than 150 deg. C resulted in significant morphological changes due to the dehydration reaction of Mg(OH){sub 2} to form MgO. Thus, it was found that the sample annealed at 150 deg. C exhibited a better corrosion resistance than the other samples, which were analyzed by taking an equivalent circuit model into account.

  5. Characterization of Porous Phosphate Coatings Enriched with Magnesium or Zinc on CP Titanium Grade 2 under DC Plasma Electrolytic Oxidation

    Directory of Open Access Journals (Sweden)

    Krzysztof Rokosz

    2018-02-01

    Full Text Available The aim of the paper is to study and determine the effect of voltage increasing from 500 up to 650 VDC on chemical and electrochemical properties of the obtained porous coatings with plasma electrolytic oxidation (PEO processes, known also as micro arc oxidation (MAO. In the present paper, the chemical and electrochemical characterization of porous phosphate coatings enriched with magnesium or zinc on commercially pure (CP Titanium Grade 2 under DC-PEO obtained in electrolytes based on concentrated 85% analytically pure H3PO4 (98 g/mole acid with additions of 500 g·L−1 of zinc nitrate Zn(NO32∙6H2O or magnesium nitrate Mg(NO32∙6H2O, are described. These materials were characterized using scanning electron microscope (SEM with energy-dispersive X-ray spectroscopy (EDS, X-ray photoelectron spectroscopy (XPS and glow discharge optical emission spectroscopy (GDOES. It was found that the voltage of PEO process has influence on the chemical composition and thickness of the obtained porous coatings as well as on their electrochemical behavior. The higher the potential of PEO treatment, the higher the amount of zinc-to-phosphorus ratio for zinc enriched coatings was obtained, whereas in magnesium enriched coatings, the average amount of magnesium detected in PEO coating is approximately independent of the PEO voltages. Based on XPS studies, it was found out that most likely the top 10 nm of porous coatings is constructed of titanium (Ti4+, magnesium (Mg2+, zinc (Zn2+, and phosphates PO43− and/or HPO42− and/or H2PO4− and/or P2O74−. On the basis of GDOES studies, a four-sub-layer model of PEO coatings is proposed. Analysis of the potentiodynamic corrosion curves allowed to conclude that the best electrochemical repeatability was noted for magnesium and zinc enriched coatings obtained at 575 VDC.

  6. OH – on plasma electrolytic oxidation of Ti–5Mo–4V–3Al

    Indian Academy of Sciences (India)

    Corrosion resistance is evaluated by open circuit potential (OCP) variation of samples in NaCl 3.5% and potentiodynamic polarization. The results show that the unstable film is formed by using more aggressive PEO electrolyte. By increasing this ratio, pore size varied from fine to coarse and the rate of corrosion decreased ...

  7. Application of sol gel spin coated yttria-stabilized zirconia layers for the improvement of solid oxide fuel cell electrolytes produced by atmospheric plasma spraying

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Lars [University of British Columbia, Department of Materials Engineering, 309-6350 Stores Road, Vancouver, British Columbia, V6T 1Z4 (Canada); National Research Council, Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, British Columbia, V6T 1W5 (Canada); Kesler, Olivera [National Research Council, Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, British Columbia, V6T 1W5 (Canada); University of British Columbia, Department of Mechanical Engineering, 2054-6250 Applied Science Lane, Vancouver, British Columbia, V6T 1Z4 (Canada); Tang, Zhaolin; Burgess, Alan [Northwest Mettech Corp., 467 Mountain Hwy, North Vancouver, British Columbia, V7J 2L3 (Canada)

    2007-05-15

    Due to its high thermal stability and purely oxide ionic conductivity, yttria-stabilized zirconia (YSZ) is the most commonly used electrolyte material for solid oxide fuel cells (SOFCs). Standard electrolyte fabrication techniques for planar SOFCs involve wet ceramic techniques such as tape-casting or screen printing, requiring sintering steps at temperatures above 1300 C. Plasma spraying (PS) may provide a more rapid and cost efficient method to produce SOFCs without sintering. High-temperature sintering requires long processing times and can lead to oxidation of metal alloys used as mechanical supports, or to detrimental interreactions between the electrolyte and adjacent electrode layers. This study investigates the use of spin coated sol gel derived YSZ precursor solutions to fill the pores present in plasma sprayed YSZ layers, and to enhance the surface area for reaction at the electrolyte-cathode interface, without the use of high-temperature firing steps. The effects of different plasma conditions and sol concentrations and solid loadings on the gas permeability and fuel cell performance have been investigated. (author)

  8. Adjustment of the ratio of Ca/P in the ceramic coating on Mg alloy by plasma electrolytic oxidation

    International Nuclear Information System (INIS)

    Yao Zhongping; Li Liangliang; Jiang Zhaohua

    2009-01-01

    The ceramic coatings containing Ca and P were prepared on AZ91D Mg alloy by plasma electrolytic oxidation technique in NaOH system and Na 2 SiO 3 system, respectively. The phase composition, morphology and the element distribution of the coatings was studied by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The corrosion resistance of the coatings was examined by polarizing curve methods in a 0.9% NaCl solution. In NaOH system, there were a large number of micro-holes distributing evenly on the surface of the coating, and the coating was mainly composed of Mg, Al, P and Ca. In Na 2 SiO 3 system, the micro-holes in the coatings were reduced greatly in number and the distribution of the micro-holes was uneven, and the coating was mainly composed of Mg, Al, Si, P and Ca. The ratio of Ca/P in the coating can be controlled by the adjustment of the technique parameters to a certain extent. The adjustment of the concentration of Ca 2+ in the electrolyte was an effective method to change the ratio of Ca/P in the coating in both systems; the reaction time and the working voltage for the adjustment of the ratio of Ca/P in the coating was more suitable for the NaSi 2 O 3 system than the NaOH system. The polarizing curve tests showed the coatings improved the corrosion resistance of the AZ91D Mg alloy in 0.9% NaCl solution by nearly two orders of magnitude.

  9. Magnesium Oxide (MgO) pH-sensitive Sensing Membrane in Electrolyte-Insulator-Semiconductor Structures with CF4 Plasma Treatment.

    Science.gov (United States)

    Kao, Chyuan-Haur; Chang, Chia Lung; Su, Wei Ming; Chen, Yu Tzu; Lu, Chien Cheng; Lee, Yu Shan; Hong, Chen Hao; Lin, Chan-Yu; Chen, Hsiang

    2017-08-03

    Magnesium oxide (MgO) sensing membranes in pH-sensitive electrolyte-insulator-semiconductor structures were fabricated on silicon substrate. To optimize the sensing capability of the membrane, CF 4 plasma was incorporated to improve the material quality of MgO films. Multiple material analyses including FESEM, XRD, AFM, and SIMS indicate that plasma treatment might enhance the crystallization and increase the grain size. Therefore, the sensing behaviors in terms of sensitivity, linearity, hysteresis effects, and drift rates might be improved. MgO-based EIS membranes with CF 4 plasma treatment show promise for future industrial biosensing applications.

  10. Preparation and in vitro evaluation of nanostructured TiO2/TCP composite coating by plasma electrolytic oxidation

    International Nuclear Information System (INIS)

    Hu, Hongjie; Liu, Xuanyong; Ding, Chuanxian

    2010-01-01

    Porous and nanostructured TiO 2 /tricalcium phosphate (TCP) composite coating on titanium substrate was prepared by plasma electrolytic oxidation (PEO). The microstructure and phase composition of the coating were characterized using scanning electron microscopy and X-ray diffraction. Its bioactivity was evaluated by simulated body fluid (SBF) immersion tests. MG63 cells were cultured on the surface of the coating to investigate its cytocompatibility. Potentiodynamic polarization tests were applied to measure its corrosion resistance. The results revealed that rough and hydrophilic TiO 2 /TCP composite coating with pores of several micrometers and grains of 50-200 nm was prepared by one-step PEO treatment. The TiO 2 /TCP composite coating showed good apatite-forming ability in SBF, and the TCP phase in the coating played an important role in inducing apatite formation. MG63 cells could adhere and proliferate on the surface of the coating, indicating its good cytocompatibility. The composite coating also exhibited good corrosion resistance in 0.9% NaCl solution.

  11. Influence of chloride ion concentration on the electrochemical corrosion behaviour of plasma electrolytic oxidation coated AM50 magnesium alloy

    International Nuclear Information System (INIS)

    Liang, J.; Srinivasan, P. Bala; Blawert, C.; Dietzel, W.

    2010-01-01

    The electrochemical degradation of a silicate- and a phosphate-based plasma electrolytic oxidation (PEO) coated AM50 magnesium alloy obtained using a pulsed DC power supply was investigated using potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) in NaCl solutions of different chloride ion concentrations viz., 0.01 M, 0.1 M, 0.5 M and 1 M. The surface of the PEO coated specimens after 50 h of immersion/EIS testing was examined by optical microscopy and scanning electron microscopy. The results showed that the corrosion deterioration of PEO coated magnesium alloy in NaCl solutions was significantly influenced by chloride ion concentration. The silicate-based coating was found to offer a superior corrosion resistance to the magnesium substrate than the phosphate-based coatings in lower chloride ion concentration NaCl solutions (0.01 M and 0.1 M NaCl). On the other hand both these PEO coatings were found to be highly susceptible to localized damage, and could not provide an effective corrosion protection to Mg alloy substrate in solutions containing higher chloride concentrations (0.5 M and 1 M). The extent of localized damage was observed to be more with increase in chloride concentration in both the cases.

  12. Properties of nanostructured undoped ZrO{sub 2} thin film electrolytes by plasma enhanced atomic layer deposition for thin film solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Gu Young; Noh, Seungtak; Lee, Yoon Ho; Cha, Suk Won, E-mail: ybkim@hanyang.ac.kr, E-mail: swcha@snu.ac.kr [Department of Mechanical and Aerospace Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Ji, Sanghoon [Graduate School of Convergence Science and Technology, Seoul National University, Iui-dong, Yeongtong-gu, Suwon 443-270 (Korea, Republic of); Hong, Soon Wook; Koo, Bongjun; Kim, Young-Beom, E-mail: ybkim@hanyang.ac.kr, E-mail: swcha@snu.ac.kr [Department of Mechanical Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791 (Korea, Republic of); An, Jihwan [Manufacturing Systems and Design Engineering Programme, Seoul National University of Science and Technology, 232 Gongneung-ro, Nowon-gu, Seoul 139-743 (Korea, Republic of)

    2016-01-15

    Nanostructured ZrO{sub 2} thin films were prepared by thermal atomic layer deposition (ALD) and by plasma-enhanced atomic layer deposition (PEALD). The effects of the deposition conditions of temperature, reactant, plasma power, and duration upon the physical and chemical properties of ZrO{sub 2} films were investigated. The ZrO{sub 2} films by PEALD were polycrystalline and had low contamination, rough surfaces, and relatively large grains. Increasing the plasma power and duration led to a clear polycrystalline structure with relatively large grains due to the additional energy imparted by the plasma. After characterization, the films were incorporated as electrolytes in thin film solid oxide fuel cells, and the performance was measured at 500 °C. Despite similar structure and cathode morphology of the cells studied, the thin film solid oxide fuel cell with the ZrO{sub 2} thin film electrolyte by the thermal ALD at 250 °C exhibited the highest power density (38 mW/cm{sup 2}) because of the lowest average grain size at cathode/electrolyte interface.

  13. Fabrication of Coatings on the Surface of Magnesium Alloy by Plasma Electrolytic Oxidation Using ZrO2 and SiO2 Nanoparticles

    Directory of Open Access Journals (Sweden)

    S. V. Gnedenkov

    2015-01-01

    Full Text Available Results of investigation of the incorporation of zirconia and silica nanoparticles into the coatings formed on magnesium alloy by plasma electrolytic oxidation are presented. Comprehensive research of electrochemical and mechanical properties of obtained coatings was carried out. It was established that the polarization resistance of the samples with a coating containing zirconia nanoparticles is two times higher than that for the sample with base PEO layer. One of the important reasons for improving the protective properties of coatings formed in electrolytes containing nanoparticles consists in enhanced morphological characteristics, in particular, the porosity decrease and increase of thickness and resistivity (up to two orders of magnitude for ZrO2-containing coating of porousless sublayer in comparison with base PEO layer. Incorporation of silica and zirconia particles into the coating increases the mechanical performances. The layers containing nanoparticles have greater hardness and are more wear resistant in comparison with the coatings formed in the base electrolyte.

  14. Fractal approach to surface roughness of TiO{sub 2}/WO{sub 3} coatings formed by plasma electrolytic oxidation process

    Energy Technology Data Exchange (ETDEWEB)

    Rožić, L.J., E-mail: ljrozic@nanosys.ihtmbg.ac.rs [University of Belgrade, IChTM-Department of Catalysis and Chemical Engineering, Njegoševa 12, Belgrade (Serbia); Petrović, S.; Radić, N. [University of Belgrade, IChTM-Department of Catalysis and Chemical Engineering, Njegoševa 12, Belgrade (Serbia); Stojadinović, S. [University of Belgrade, Faculty of Physics, Studentski trg 12-16, Belgrade (Serbia); Vasilić, R. [Faculty of Environmental Governance and Corporate Responsibility, Educons University, Vojvode Putnika 87, Sremska Kamenica (Serbia); Stefanov, P. [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Sofia 1113 (Bulgaria); Grbić, B. [University of Belgrade, IChTM-Department of Catalysis and Chemical Engineering, Njegoševa 12, Belgrade (Serbia)

    2013-07-31

    In this study, we have shown that atomic force microscopy is a powerful technique to study the fractal parameters of TiO{sub 2}/WO{sub 3} coatings prepared by plasma electrolytic oxidation (PEO) process. Since the surface roughness of obtained oxide coatings affects their physical properties, an accurate description of roughness parameters is highly desirable. The surface roughness, described by root mean squared and arithmetic average values, is analyzed considering the scans of a series of atomic force micrographs. The results show that the oxide coatings exhibit lower surface roughness in initial stage of PEO process. Also, the surfaces of TiO{sub 2}/WO{sub 3} coatings exhibit fractal behavior. Positive correlation between the fractal dimension and surface roughness of the surfaces of TiO{sub 2}/WO{sub 3} coatings in initial stage of PEO process was found. - Highlights: • TiO{sub 2}/WO{sub 3} coatings were obtained by plasma electrolytic oxidation. • Oxide coatings exhibit lower surface roughness in initial stage of process. • The surfaces of TiO{sub 2}/WO{sub 3} coatings exhibit fractal behavior.

  15. Effect of individual discharge cascades on the microstructure of plasma electrolytic oxidation coatings

    International Nuclear Information System (INIS)

    Troughton, S.C.; Nominé, A.; Dean, J.; Clyne, T.W.

    2016-01-01

    Highlights: • High speed current/video monitoring of discharge cascades. • SEM and X-ray Computed Tomography of cascade sites. • Effects of supply frequency and process interruption. • Explanation of cascade localisation. - Abstract: Short duration (∼1 s) PEO treatments have been applied to aluminium alloy samples on which coatings of thickness ∼100 μm had previously been created. This was done using the small area electrical monitoring system previously developed in the Gordon Laboratory in Cambridge. Voltage supply frequencies of 50 Hz and 2.5 kHz were employed. Fairly high resolution SEM micrographs were taken, covering the whole surface of small area samples (ie over a circular area of diameter about 0.9 mm). This was done both before and after the 1 s PEO treatments. X-ray tomographic data were also obtained in the vicinity of a recently-completed set of discharges. The outcomes of these observations were correlated with synchronised high speed electrical monitoring and video photography, carried out during the PEO treatment periods. Localised cascades (comprising hundreds of individual discharges) were observed in all cases, persisting throughout the 1 s periods and also reappearing in the same location when a second 1 s PEO treatment was applied to the same sample. This repetition of discharges at the same location is apparently due to the deep pores associated with these sites, creating a pathway of low electrical resistance, even after appreciable oxidation has occurred in the vicinity. Observations were made of the way in which the surfaces were reconstructed locally as discharge cascades occurred. With the high frequency voltage supply, discharge lifetimes were limited to the half-cycle period (of 200 μs), but in other respects the cascades were similar to those with the lower frequency. However, some discharges occurred during cathodic half-cycles with the high frequency supply, at the same location as the anodic discharges in the cascade

  16. Effect of individual discharge cascades on the microstructure of plasma electrolytic oxidation coatings

    Energy Technology Data Exchange (ETDEWEB)

    Troughton, S.C. [Department of Materials Science & Metallurgy, Cambridge Universitym 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); Nominé, A. [Department of Physical Sciences, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Dean, J. [Department of Materials Science & Metallurgy, Cambridge Universitym 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); Clyne, T.W., E-mail: twc10@cam.ac.uk [Department of Materials Science & Metallurgy, Cambridge Universitym 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom)

    2016-12-15

    Highlights: • High speed current/video monitoring of discharge cascades. • SEM and X-ray Computed Tomography of cascade sites. • Effects of supply frequency and process interruption. • Explanation of cascade localisation. - Abstract: Short duration (∼1 s) PEO treatments have been applied to aluminium alloy samples on which coatings of thickness ∼100 μm had previously been created. This was done using the small area electrical monitoring system previously developed in the Gordon Laboratory in Cambridge. Voltage supply frequencies of 50 Hz and 2.5 kHz were employed. Fairly high resolution SEM micrographs were taken, covering the whole surface of small area samples (ie over a circular area of diameter about 0.9 mm). This was done both before and after the 1 s PEO treatments. X-ray tomographic data were also obtained in the vicinity of a recently-completed set of discharges. The outcomes of these observations were correlated with synchronised high speed electrical monitoring and video photography, carried out during the PEO treatment periods. Localised cascades (comprising hundreds of individual discharges) were observed in all cases, persisting throughout the 1 s periods and also reappearing in the same location when a second 1 s PEO treatment was applied to the same sample. This repetition of discharges at the same location is apparently due to the deep pores associated with these sites, creating a pathway of low electrical resistance, even after appreciable oxidation has occurred in the vicinity. Observations were made of the way in which the surfaces were reconstructed locally as discharge cascades occurred. With the high frequency voltage supply, discharge lifetimes were limited to the half-cycle period (of 200 μs), but in other respects the cascades were similar to those with the lower frequency. However, some discharges occurred during cathodic half-cycles with the high frequency supply, at the same location as the anodic discharges in the cascade

  17. Systematic understanding of corrosion behavior of plasma electrolytic oxidation treated AZ31 magnesium alloy using a mouse model of subcutaneous implant

    International Nuclear Information System (INIS)

    Jang, Yongseok; Tan, Zongqing; Jurey, Chris; Collins, Boyce; Badve, Aditya; Dong, Zhongyun; Park, Chanhee; Kim, Cheol Sang; Sankar, Jagannathan; Yun, Yeoheung

    2014-01-01

    This study was conducted to identify the differences between corrosion rates, corrosion types, and corrosion products in different physiological environments for AZ31 magnesium alloy and plasma electrolytic oxidation (PEO) treated AZ31 magnesium alloy. In vitro and in vivo tests were performed in Hank's Balanced Salt Solution (HBSS) and mice for 12 weeks, respectively. The corrosion rates of both AZ31 magnesium alloy and PEO treated AZ31 magnesium alloy were calculated based on DC polarization curves, volume of hydrogen evolution, and the thickness of corrosion products formed on the surface. Micro X-ray computed tomography (Micro-CT), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) were used to analyze morphological and chemical characterizations of corrosion products. The results show that there is more severe localized corrosion after in vitro test in HBSS; however, the thicknesses of corrosion products formed on the surface for AZ31 magnesium alloy and PEO treated AZ31 magnesium alloy in vivo were about 40% thicker than the thickness of corrosion products generated in vitro. The ratio of Ca and P (Ca/P) in the corrosion products also differed. The Ca deficient region and higher content of Al in corrosion product than AZ31 magnesium alloy were identified after in vivo test in contrast with the result of in vitro test. - Highlights: • Effects of plasma electrolytic oxidation on AZ31 in vitro and in vivo • Retardation of degradation via plasma electrolytic oxidation in vitro and in vivo • Differentiation of in vitro and in vivo corrosion types and products

  18. Systematic understanding of corrosion behavior of plasma electrolytic oxidation treated AZ31 magnesium alloy using a mouse model of subcutaneous implant

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Yongseok [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC, 27411 (United States); Tan, Zongqing [Internal Medicine, College of Medicine, University of Cincinnati, OH 45211 (United States); Jurey, Chris [Luke Engineering, Wadsworth, OH 44282 (United States); Collins, Boyce [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC, 27411 (United States); Badve, Aditya [Business and Biology, The University of North Carolina at Chapel Hill, NC 27514 (United States); Dong, Zhongyun [Internal Medicine, College of Medicine, University of Cincinnati, OH 45211 (United States); Park, Chanhee; Kim, Cheol Sang [Department of Bio-nano System Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Sankar, Jagannathan [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC, 27411 (United States); Yun, Yeoheung, E-mail: yyun@ncat.edu [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC, 27411 (United States)

    2014-12-01

    This study was conducted to identify the differences between corrosion rates, corrosion types, and corrosion products in different physiological environments for AZ31 magnesium alloy and plasma electrolytic oxidation (PEO) treated AZ31 magnesium alloy. In vitro and in vivo tests were performed in Hank's Balanced Salt Solution (HBSS) and mice for 12 weeks, respectively. The corrosion rates of both AZ31 magnesium alloy and PEO treated AZ31 magnesium alloy were calculated based on DC polarization curves, volume of hydrogen evolution, and the thickness of corrosion products formed on the surface. Micro X-ray computed tomography (Micro-CT), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) were used to analyze morphological and chemical characterizations of corrosion products. The results show that there is more severe localized corrosion after in vitro test in HBSS; however, the thicknesses of corrosion products formed on the surface for AZ31 magnesium alloy and PEO treated AZ31 magnesium alloy in vivo were about 40% thicker than the thickness of corrosion products generated in vitro. The ratio of Ca and P (Ca/P) in the corrosion products also differed. The Ca deficient region and higher content of Al in corrosion product than AZ31 magnesium alloy were identified after in vivo test in contrast with the result of in vitro test. - Highlights: • Effects of plasma electrolytic oxidation on AZ31 in vitro and in vivo • Retardation of degradation via plasma electrolytic oxidation in vitro and in vivo • Differentiation of in vitro and in vivo corrosion types and products.

  19. Corrosion behaviors and effects of corrosion products of plasma electrolytic oxidation coated AZ31 magnesium alloy under the salt spray corrosion test

    Science.gov (United States)

    Wang, Yan; Huang, Zhiquan; Yan, Qin; Liu, Chen; Liu, Peng; Zhang, Yi; Guo, Changhong; Jiang, Guirong; Shen, Dejiu

    2016-08-01

    The effects of corrosion products on corrosion behaviors of AZ31 magnesium alloy with a plasma electrolytic oxidation (PEO) coating were investigated under the salt spray corrosion test (SSCT). The surface morphology, cross-sectional microstructure, chemical and phase compositions of the PEO coating were determined using scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction analysis (XRD), respectively. Further, the corrosion process of the samples under the SSCT was examined in a non-aqueous electrolyte (methanol) using electrochemical impedance spectroscopy (EIS) coupled with equivalent circuit. The results show that the inner layer of the coating was destroyed firstly and the corrosion products have significant effects on the corrosion behaviors of the coating. The results above are discussed and an electrochemical corrosion model is proposed in the paper.

  20. Plasma electrolytic oxidation of A1050 aluminium alloy in homogeneous silicate-alkaline electrolytes with edta{sup 4−} complexes of Fe, Co, Ni, Cu, La and Ba under alternating polarization conditions

    Energy Technology Data Exchange (ETDEWEB)

    Rogov, A.B., E-mail: alex-lab@bk.ru [Nikolaev Institute of Inorganic Chemistry, 3, Acad. Lavrentiev Ave., Novosibirsk, 630090 (Russian Federation); Scientific and Technical Centre “Pokrytie-A” (OOO), 15, Dzerzhinskogo Ave., Novosibirsk, 630015 (Russian Federation)

    2015-11-01

    This work is devoted to the synthesis of coatings containing a number of transition elements by plasma electrolytic oxidation (PEO) on aluminium A1050 alloy. The paper discusses PEO coatings obtained in silicate-alkaline electrolytes containing complexes of Fe, Co, Ni, Cu, La and Ba with ethylenediaminetetraacetic anion edta{sup 4−}. It is also focused on the chemical basis of the electrolyte components choice and their role in the process of PEO. Possible mechanism of coating formation process is also discussed. Alternating current mode (symmetrical sinusoidal current pulses, initial average current density - 100 mA cm{sup −2}) was used to produce the coatings. The PEO process was characterized by behaviours of the anodic and cathodic peak voltage curves. Coating surfaces and cross sections are studied by optical dark field microscopy and scanning electron microscopy, X-ray and energy dispersive analysis. - Highlights: • Alkaline homogeneous electrolyte with transition metal-edta{sup 4-} complexes. • Coatings contain Fe, Co, Ni, Cu, La, Ba elements in alumina-silica matrix. • Alternating symmetric sinusoidal current of 100 mA cm{sup −2} was applied. • Borax buffer solution and silicate passivating agent were used.

  1. Effects of cathode current density on structure and corrosion resistance of plasma electrolytic oxidation coatings formed on ZK60 Mg alloy

    International Nuclear Information System (INIS)

    Su Peibo; Wu Xiaohong; Guo Yun; Jiang Zhaohua

    2009-01-01

    Current density is a key factor in plasma electrolytic oxidation (PEO) process. The aim of this paper is to study the effects of cathode current density on the composition, morphology, and corrosion resistance of ceramic coatings on ZK60 magnesium alloy prepared through bi-polar plasma electrolytic oxidation in Na 3 PO 4 solution. The phase composition, morphology, and corrosion resistance were studied by X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Electrochemical Impedance Spectroscopy (EIS) and potentiodynamic polarization in 3.5% NaCl solution. It is found that the as-produced coatings are only composed of MgO. The increase of cathode current density made the coatings less porous and more compact. Analysis of EIS and potentiodynamic polarization technique on the samples shows that the corrosion resistance of the coated samples is better than that of ZK60 magnesium alloy, and that a bigger cathode current density can improve the corrosion resistance of as-prepared coatings.

  2. Study of the effect of Pyrophosphate in low voltage Plasma Electrolytic Oxidation on the corrosion resistance of AZ31B Magnesium alloy

    International Nuclear Information System (INIS)

    Yun, Jae Gon; Kim, Eng Chan; Kim, Ki Hong

    2016-01-01

    In this study, low voltage Plasma Electrolytic Oxidation (PEO) was utilized to eliminate the drawbacks of high voltage PEO such as high cost, dimensional deformation, and porosity. Low voltage PEO produces a thin coating, which leads to low corrosion resistance. In order to solve this problem, 0.1⁓0.6 M pyrophosphates were added to a bath containing 1.4 M NaOH and 0.35 M Na_2SiO_3.PEO at 70V was conducted at 25℃ for 3 minutes. The chemical composition, morphology, and corrosion resistance of the anodized coating were analyzed. The anodized film was composed of MgO, Mg_2SiO_4, and Mg_2O_7P_2. Themorphology of the film showed a inappropriately dense structure and low porosity in the anodized layers. It is found that low voltage Plasma Electrolytic Oxidation in cooperation with phosphating treatment can provide good corrosion protection for the AZ31B magnesium alloy.

  3. Study of the effect of Pyrophosphate in low voltage Plasma Electrolytic Oxidation on the corrosion resistance of AZ31B Magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Jae Gon; Kim, Eng Chan [Yeungnam University, Gyeongsan (Korea, Republic of); Kim, Ki Hong [Catholic University of Daegu, Gyeongsan (Korea, Republic of)

    2016-01-15

    In this study, low voltage Plasma Electrolytic Oxidation (PEO) was utilized to eliminate the drawbacks of high voltage PEO such as high cost, dimensional deformation, and porosity. Low voltage PEO produces a thin coating, which leads to low corrosion resistance. In order to solve this problem, 0.1⁓0.6 M pyrophosphates were added to a bath containing 1.4 M NaOH and 0.35 M Na{sub 2}SiO{sub 3}.PEO at 70V was conducted at 25℃ for 3 minutes. The chemical composition, morphology, and corrosion resistance of the anodized coating were analyzed. The anodized film was composed of MgO, Mg{sub 2}SiO{sub 4}, and Mg{sub 2}O{sub 7}P{sub 2}. Themorphology of the film showed a inappropriately dense structure and low porosity in the anodized layers. It is found that low voltage Plasma Electrolytic Oxidation in cooperation with phosphating treatment can provide good corrosion protection for the AZ31B magnesium alloy.

  4. High-compactness coating grown by plasma electrolytic oxidation on AZ31 magnesium alloy in the solution of silicate–borax

    International Nuclear Information System (INIS)

    Shen, M.J.; Wang, X.J.; Zhang, M.F.

    2012-01-01

    Highlights: ► The MgO ceramic coating has been prepared on the surface of AZ31 magnesium alloy by plasma electrolytic oxidation in the borax-doped silicate system. ► Boron element exists in the PEO films in the form of noncrystal. ► The microhardness and compactness of doped ceramic coating are much higher than that of the substrate and undoped ceramic coating, and this doped coated sample shows better wear-resisting property. - Abstract: A ceramic coating was formed on the surface of AZ31 magnesium alloy by plasma electrolytic oxidation (PEO) in the silicate solution with and without borax doped. The composition, morphology, elements and roughness as well as mechanical property of the coating were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectrometry (EDS), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and reciprocal-sliding tribometer. The results show that the PEO coating is mainly composed of magnesia. When using borax dope, boron element is permeating into the coating and the boron containing phase exist in the form of amorphous. In addition, the microhardness and compactness of the PEO coating are improved significantly due to doped borax.

  5. Effect of (NaPO3)6 concentrations on corrosion resistance of plasma electrolytic oxidation coatings formed on AZ91D magnesium alloy

    International Nuclear Information System (INIS)

    Luo Haihe; Cai Qizhou; Wei Bokang; Yu Bo; Li Dingjun; He Jian; Liu Ze

    2008-01-01

    Different plasma electrolytic oxidation (PEO) coatings were prepared on AZ91D magnesium alloy in electrolytes containing various concentrations of (NaPO 3 ) 6 . The morphologies, chemical compositions and corrosion resistance of the PEO coatings were characterized by environmental scanning electron microscopy (ESEM), X-ray diffractometer (XRD), energy dispersive analysis of X-rays (EDAX), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) test. The results showed that the PEO coatings were mainly composed of MgO, Mg 2 SiO 4 , MgAl 2 O 4 and amorphous compounds. As the (NaPO 3 ) 6 concentrations increased from 0 to 10 g/l, the thickness and surface roughness of the coatings approximately linearly increased; the MgO and Mg 2 SiO 4 phase increased within the concentration range of 0-3 and 0-5 g/l, and then decreased within the range of 3-10 and 5-10 g/l, respectively, while the MgAl 2 O 4 phase gradually decreased. Moreover, the corrosion resistance of the coatings increased within the range of 0-5 g/l and then decreased within the range of 5-10 g/l. The best corrosion resistance coating was obtained in electrolyte containing 5 g/l (NaPO 3 ) 6 , it had the most compact microstructure. Besides, a reasonable equivalent circuit was established, and the fitting results were consistent with the results of the EIS test

  6. Comparison of electrochemical corrosion behaviour of MgO and ZrO2 coatings on AM50 magnesium alloy formed by plasma electrolytic oxidation

    International Nuclear Information System (INIS)

    Liang, J.; Srinivasan, P. Bala; Blawert, C.; Dietzel, W.

    2009-01-01

    Two types of PEO coatings were produced on AM50 magnesium alloy using pulsed DC plasma electrolytic oxidation process in an alkaline phosphate and acidic fluozirconate electrolytes, respectively. The phase composition and microstructure of these PEO coatings were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The corrosion behaviour of the coated samples was evaluated by open circuit potential (OCP) measurements, potentiodynamic polarization tests, and electrochemical impedance spectroscopy (EIS) in neutral 0.1 M NaCl solution. The results showed that PEO coating prepared from alkaline phosphate electrolyte consisted of only MgO and on the other hand the one formed in acidic fluozirconate solution was mainly composed of ZrO 2 , MgF 2 . Electrochemical corrosion tests indicated that the phase composition of PEO coating has a significant effect on the deterioration process of coated magnesium alloy in this corrosive environment. The PEO coating that was composed of only MgO suffered from localized corrosion in the 50 h exposure studies, whereas the PEO coating with ZrO 2 compounds showed a much superior stability during the corrosion tests and provided an efficient corrosion protection. The results showed that the preparation of PEO coating with higher chemical stability compounds offers an opportunity to produce layers that could provide better corrosion protection to magnesium alloys.

  7. The formation of tungsten doped Al{sub 2}O{sub 3}/ZnO coatings on aluminum by plasma electrolytic oxidation and their application in photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Stojadinović, Stevan, E-mail: sstevan@ff.bg.ac.rs [University of Belgrade, Faculty of Physics, Studentski trg 12-16, 11000 Belgrade (Serbia); Vasilić, Rastko [University of Belgrade, Faculty of Physics, Studentski trg 12-16, 11000 Belgrade (Serbia); Radić, Nenad [University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Department of Catalysis and Chemical Engineering, Njegoševa 12, 11000 Belgrade (Serbia); Tadić, Nenad [University of Belgrade, Faculty of Physics, Studentski trg 12-16, 11000 Belgrade (Serbia); Stefanov, Plamen [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Block 11, 1113 Sofia (Bulgaria); Grbić, Boško [University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Department of Catalysis and Chemical Engineering, Njegoševa 12, 11000 Belgrade (Serbia)

    2016-07-30

    Highlights: • Tungsten doped Al{sub 2}O{sub 3}/ZnO coatings are formed by plasma electrolytic oxidation (PEO). • Coatings are mainly composed of alpha alumina, ZnO and metallic tungsten. • Photocatalytic activity of doped Al{sub 2}O{sub 3}/ZnO coatings is higher than of undoped ones. • The increase of photoluminescence corresponds to decrease of photocatalytic activity. • Tungsten acts as a charge trap to reduce the recombination rate of electron/hole pairs. - Abstract: Tungsten doped Al{sub 2}O{sub 3}/ZnO coatings are formed by plasma electrolytic oxidation of aluminum substrate in supporting electrolyte (0.1 M boric acid + 0.05 M borax + 2 g/L ZnO) with addition of different concentrations of Na{sub 2}WO{sub 4}·2H{sub 2}O. The morphology, crystal structure, chemical composition, and light absorption characteristics of formed surface coatings are investigated. The X-ray diffraction and X-ray photoelectron spectroscopy results indicate that formed surface coatings consist of alpha and gamma phase of Al{sub 2}O{sub 3}, ZnO, metallic tungsten and WO{sub 3}. Obtained results showed that incorporated tungsten does not have any influence on the absorption spectra of Al{sub 2}O{sub 3}/ZnO coatings, which showed invariable band edge at about 385 nm. The photocatalytic activity of undoped and tungsten doped Al{sub 2}O{sub 3}/ZnO coatings is estimated by the photodegradation of methyl orange. The photocatalytic activity of tungsten doped Al{sub 2}O{sub 3}/ZnO coatings is higher thanof undoped Al{sub 2}O{sub 3}/ZnO coatings; the best photocatalytic activity is ascribed to coatings formed in supporting electrolyte with addition of 0.3 g/L Na{sub 2}WO{sub 4}·2H{sub 2}O. Tungsten in Al{sub 2}O{sub 3}/ZnO coatings acts as a charge trap, thus reducing the recombination rate of photogenerated electron-hole pairs. The results of PL measurements are in agreement with photocatalytic activity. Declining PL intensity corresponds to increasing photocatalytic activity of the

  8. The formation of tungsten doped Al_2O_3/ZnO coatings on aluminum by plasma electrolytic oxidation and their application in photocatalysis

    International Nuclear Information System (INIS)

    Stojadinović, Stevan; Vasilić, Rastko; Radić, Nenad; Tadić, Nenad; Stefanov, Plamen; Grbić, Boško

    2016-01-01

    Highlights: • Tungsten doped Al_2O_3/ZnO coatings are formed by plasma electrolytic oxidation (PEO). • Coatings are mainly composed of alpha alumina, ZnO and metallic tungsten. • Photocatalytic activity of doped Al_2O_3/ZnO coatings is higher than of undoped ones. • The increase of photoluminescence corresponds to decrease of photocatalytic activity. • Tungsten acts as a charge trap to reduce the recombination rate of electron/hole pairs. - Abstract: Tungsten doped Al_2O_3/ZnO coatings are formed by plasma electrolytic oxidation of aluminum substrate in supporting electrolyte (0.1 M boric acid + 0.05 M borax + 2 g/L ZnO) with addition of different concentrations of Na_2WO_4·2H_2O. The morphology, crystal structure, chemical composition, and light absorption characteristics of formed surface coatings are investigated. The X-ray diffraction and X-ray photoelectron spectroscopy results indicate that formed surface coatings consist of alpha and gamma phase of Al_2O_3, ZnO, metallic tungsten and WO_3. Obtained results showed that incorporated tungsten does not have any influence on the absorption spectra of Al_2O_3/ZnO coatings, which showed invariable band edge at about 385 nm. The photocatalytic activity of undoped and tungsten doped Al_2O_3/ZnO coatings is estimated by the photodegradation of methyl orange. The photocatalytic activity of tungsten doped Al_2O_3/ZnO coatings is higher thanof undoped Al_2O_3/ZnO coatings; the best photocatalytic activity is ascribed to coatings formed in supporting electrolyte with addition of 0.3 g/L Na_2WO_4·2H_2O. Tungsten in Al_2O_3/ZnO coatings acts as a charge trap, thus reducing the recombination rate of photogenerated electron-hole pairs. The results of PL measurements are in agreement with photocatalytic activity. Declining PL intensity corresponds to increasing photocatalytic activity of the coatings, indicating slower recombination of electron-hole pairs.

  9. Electrolytic plasma processing of steel surfaces

    International Nuclear Information System (INIS)

    Bejar, M.A; Araya, R.N; Baeza, B

    2006-01-01

    The thermo-chemical treatments of steels with plasma is normally carried out in low-pressure ionized gaseous atmospheres. Among the treatments used most often are: nitruration, carburization and boronized. A plasma can also generate at atmospheric pressure. One way to produce it is with an electrochemical cell that works at a relatively high inter-electrode voltage and under conditions of heavy gas generation. This type of plasma is known as electrolytic plasma. This work studies the feasibility of using electrolytic plasma for the surface processing of steels. Two processes were selected: boronized and nitruration., for the hardening of two types of steel: one with low carbon (1020) and one with low alloy (4140). In the case of the nitruration, the 1020 steel was first aluminized. The electrolytes were aqueous solutions of borax for the boronizing and urea for the nitruration. The electrolytic plasmas were classified qualitatively, in relation with their luminosity by low, medium and high intensity. The boronizing was carried out with low intensity plasmas for a period of one hour. The nitruration was performed with plasmas of different intensities and for period of a few minutes to half an hour. The test pieces processed by electrolytic plasma were characterized by micro-hardness tests and X-ray diffraction. The maximum surface hardnesses obtained for the 1020 and 4140 steels were the following: 300 and 700 HV for the boronizing, and 1650 and 1200 HV for the nitruration, respectively. The utilization of an electrolytic plasma permits the surface processing of steels, noticeably increasing their hardness. With this type of plasma some thermo-chemical surface treatments can be done very rapidly as well (CW)

  10. High-compactness coating grown by plasma electrolytic oxidation on AZ31 magnesium alloy in the solution of silicate-borax

    Science.gov (United States)

    Shen, M. J.; Wang, X. J.; Zhang, M. F.

    2012-10-01

    A ceramic coating was formed on the surface of AZ31 magnesium alloy by plasma electrolytic oxidation (PEO) in the silicate solution with and without borax doped. The composition, morphology, elements and roughness as well as mechanical property of the coating were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectrometry (EDS), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and reciprocal-sliding tribometer. The results show that the PEO coating is mainly composed of magnesia. When using borax dope, boron element is permeating into the coating and the boron containing phase exist in the form of amorphous. In addition, the microhardness and compactness of the PEO coating are improved significantly due to doped borax.

  11. Effects of cathode pulse at high frequency on structure and composition of Al2TiO5 ceramic coatings on Ti alloy by plasma electrolytic oxidation

    International Nuclear Information System (INIS)

    Yao Zhongping; Liu Yunfu; Xu Yongjun; Jiang Zhaohua; Wang Fuping

    2011-01-01

    Research highlights: → Al 2 TiO 5 in the coating on Ti alloy by PEO treatment changes with the increase of the cathode pulse, regardless of the amount and the grain size. → The cathode pulse brings about the decrease of γ-Al 2 O 3 and the increase of rutile TiO 2 in the coating. → The appropriate cathode pulse during PEO process is beneficial to reduce residual discharging channels and improve the density of the coating. - Abstract: The aim of this work is to investigate the effects of cathode pulse under high working frequency on structure and composition of ceramic coatings on Ti-6Al-4V alloys by plasma electrolytic oxidation (PEO). Ceramic coatings were prepared on Ti alloy by pulsed bi-polar plasma electrolytic oxidation in NaAlO 2 solution. The phase composition, morphology and element distribution in the coating were investigated by X-ray diffractometry, scanning electron microscopy and energy distribution spectroscopy, respectively. The coating was mainly composed of a large amount of Al 2 TiO 5 . As the cathode pulse was increased, the amount and grain size of Al 2 TiO 5 were first increased, and then decreased. γ-Al 2 O 3 in the coating was gradually decreased to nothing with the increase in the cathode pulse whereas rutile TiO 2 began to form in the coating. As opposed to the single-polar anode pulse mode, the cathode pulse reduced the thickness of the coatings. However, as the cathode pulse intensity continued to increase, the coating then became thicker regardless of cathode current density or pulse width. In addition, the residual discharging channels were reduced and the density of the coating was increased with the appropriate increase of the cathode pulse.

  12. Understanding corrosion behavior of Mg–Zn–Ca alloys from subcutaneous mouse model: Effect of Zn element concentration and plasma electrolytic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Yongseok [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC 27411 (United States); Tan, Zongqing [Department of Internal Medicine, College of Medicine, University of Cincinnati, Cincinnati, OH 45221 (United States); Jurey, Chris [Luke Engineering, Wadsworth, OH 44282 (United States); Xu, Zhigang [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC 27411 (United States); Dong, Zhongyun [Department of Internal Medicine, College of Medicine, University of Cincinnati, Cincinnati, OH 45221 (United States); Collins, Boyce [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC 27411 (United States); Yun, Yeoheung, E-mail: yyun@ncat.edu [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC 27411 (United States); Sankar, Jagannathan [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC 27411 (United States)

    2015-03-01

    Mg–Zn–Ca alloys are considered as suitable biodegradable metallic implants because of their biocompatibility and proper physical properties. In this study, we investigated the effect of Zn concentration of Mg–xZn–0.3Ca (x = 1, 3 and 5 wt.%) alloys and surface modification by plasma electrolytic oxidation (PEO) on corrosion behavior in in vivo environment in terms of microstructure, corrosion rate, types of corrosion, and corrosion product formation. Microstructure analysis of alloys and morphological characterization of corrosion products were conducted using x-ray computed tomography (micro-CT) and scanning electron microscopy (SEM). Elemental composition and crystal structure of corrosion products were determined using x-ray diffraction (XRD) and electron dispersive x-ray spectroscopy (EDX). The results show that 1) as-cast Mg–xZn–0.3Ca alloys are composed of Mg matrix and a secondary phase of Ca{sub 2}Mg{sub 6}Zn{sub 3} formed along grain boundaries, 2) the corrosion rate of Mg–xZn–0.3Ca alloys increases with increasing concentration of Zn in the alloy, 3) corrosion rates of alloys treated by PEO sample are decreased in in vivo environment, and 4) the corrosion products of these alloys after in vivo tests are identified as brucite (Mg(OH){sub 2}), hydroxyapatite (Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}), and magnesite (MgCO{sub 3}·3H{sub 2}O). - Highlights: • Effects of PEO and Zn concentration in Mg–xZn–0.3Ca alloys on biodegradation • Corrosion rate of Mg–xZn–0.3Ca alloys increases with increasing Zn concentration. • Plasma electrolytic oxidation retards the biodegradation of Mg–xZn–0.3Ca alloys.

  13. Structure, tribocorrosion and biocide characterization of Ca, P and I containing TiO{sub 2} coatings developed by plasma electrolytic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Sáenz de Viteri, V., E-mail: virginia.saenzdeviteri@tekniker.es [IK4-Tekniker, Polo Tecnológico de Eibar, Calle Iñaki Goenaga, 5, Eibar 20600 (Spain); Bayón, R.; Igartua, A. [IK4-Tekniker, Polo Tecnológico de Eibar, Calle Iñaki Goenaga, 5, Eibar 20600 (Spain); Barandika, G. [Departamento de Química Inorgánica, Facultad de Ciencia y Tecnología, Universidad del País Vasco, UPV/EHU, Apartado 644, Bilbao E-48080 (Spain); Moreno, J. Esteban; Peremarch, C. Pérez-Jorge; Pérez, M. Martínez [Department of Clinical Microbiology, IIS-Fundación Jiménez Díaz, Av. Reyes Católicos 2, Madrid 28040 (Spain)

    2016-03-30

    Graphical abstract: - Highlights: • Ca, P and I doped TiO{sub 2} coatings were developed by means of plasma electrolytic oxidation (PEO) technique. • Microstructure and chemical composition of the developed coating were in depth analyzed. • The effect of wear-corrosion synergy was studied through tribocorrosion tests. • Antibacterial efficiency of iodine as biocide agent was analyzed by means of bacterial adhesion study. • A TiO{sub 2} coating with improved wear-corrosion resistance, suitable surface for cell adhesion and biocide properties was achieved. - Abstract: In hip joint implants, in particular in the stems, wear-corrosion effects can accelerate the degradation of the biomaterial. The lack of osseointegration and the risk of contracting implant-associated infections may be other reasons for a premature failure of the implant. In this work, TiO{sub 2} coatings have been developed by means of plasma electrolytic oxidation (PEO) technique in order to achieve wear-resistant hard coatings with osseointegration ability and biocide characteristics. During the PEO process, elements that favor cell growth, like Ca and P, were introduced into the coating. With the purpose of providing the coating with antibacterial properties iodine was added like biocide agent. The microstructure and chemical composition of the developed coatings were analyzed in order to see if the surface of the films was suitable for the cell attachment. The effect of wear-corrosion synergy was studied by means of tribocorrosion tests. Finally, the biocide capacity of iodine against Staphylococcus aureus and Staphylococcus epidermidis was analyzed through bacterial adhesion tests. High wear and corrosion resistance was shown in one of the developed coatings. The achieved surface microstructures seem to be appropriate to improve the osseointegration with proper pore size and porosity index. The antibacterial capacity of iodine was confirmed for S. epidermidis.

  14. Corrosion behaviors and effects of corrosion products of plasma electrolytic oxidation coated AZ31 magnesium alloy under the salt spray corrosion test

    International Nuclear Information System (INIS)

    Wang, Yan; Huang, Zhiquan; Yan, Qin; Liu, Chen; Liu, Peng; Zhang, Yi; Guo, Changhong; Jiang, Guirong; Shen, Dejiu

    2016-01-01

    Highlights: • Corrosion behaviors of a PEO coating was investigated after the salt spray test. • Corrosion products have significant effects on corrosion behaviors of the coating. • An electrochemical corrosion model is proposed. - Abstract: The effects of corrosion products on corrosion behaviors of AZ31 magnesium alloy with a plasma electrolytic oxidation (PEO) coating were investigated under the salt spray corrosion test (SSCT). The surface morphology, cross-sectional microstructure, chemical and phase compositions of the PEO coating were determined using scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction analysis (XRD), respectively. Further, the corrosion process of the samples under the SSCT was examined in a non-aqueous electrolyte (methanol) using electrochemical impedance spectroscopy (EIS) coupled with equivalent circuit. The results show that the inner layer of the coating was destroyed firstly and the corrosion products have significant effects on the corrosion behaviors of the coating. The results above are discussed and an electrochemical corrosion model is proposed in the paper.

  15. Corrosion behaviors and effects of corrosion products of plasma electrolytic oxidation coated AZ31 magnesium alloy under the salt spray corrosion test

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yan; Huang, Zhiquan; Yan, Qin; Liu, Chen; Liu, Peng; Zhang, Yi [State Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Guo, Changhong; Jiang, Guirong [College of Mechanical Engineering, Yanshan University, Qinhuangdao 066004 (China); Shen, Dejiu, E-mail: DejiuShen@163.com [State Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China)

    2016-08-15

    Highlights: • Corrosion behaviors of a PEO coating was investigated after the salt spray test. • Corrosion products have significant effects on corrosion behaviors of the coating. • An electrochemical corrosion model is proposed. - Abstract: The effects of corrosion products on corrosion behaviors of AZ31 magnesium alloy with a plasma electrolytic oxidation (PEO) coating were investigated under the salt spray corrosion test (SSCT). The surface morphology, cross-sectional microstructure, chemical and phase compositions of the PEO coating were determined using scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction analysis (XRD), respectively. Further, the corrosion process of the samples under the SSCT was examined in a non-aqueous electrolyte (methanol) using electrochemical impedance spectroscopy (EIS) coupled with equivalent circuit. The results show that the inner layer of the coating was destroyed firstly and the corrosion products have significant effects on the corrosion behaviors of the coating. The results above are discussed and an electrochemical corrosion model is proposed in the paper.

  16. Surface characterization and corrosion behavior of calcium phosphate-base composite layer on titanium and its alloys via plasma electrolytic oxidation: A review paper.

    Science.gov (United States)

    Rafieerad, A R; Ashra, M R; Mahmoodian, R; Bushroa, A R

    2015-12-01

    In recent years, calcium phosphate-base composites, such as hydroxyapatite (HA) and carbonate apatite (CA) have been considered desirable and biocompatible coating layers in clinical and biomedical applications such as implants because of the high resistance of the composites. This review focuses on the effects of voltage, time and electrolytes on a calcium phosphate-base composite layer in case of pure titanium and other biomedical grade titanium alloys via the plasma electrolytic oxidation (PEO) method. Remarkably, these parameters changed the structure, morphology, pH, thickness and crystallinity of the obtained coating for various engineering and biomedical applications. Hence, the structured layer caused improvement of the biocompatibility, corrosion resistance and assignment of extra benefits for Osseo integration. The fabricated layer with a thickness range of 10 to 20 μm was evaluated for physical, chemical, mechanical and tribological characteristics via XRD, FESEM, EDS, EIS and corrosion analysis respectively, to determine the effects of the applied parameters and various electrolytes on morphology and phase transition. Moreover, it was observed that during PEO, the concentration of calcium, phosphor and titanium shifts upward, which leads to an enhanced bioactivity by altering the thickness. The results confirm that the crystallinity, thickness and contents of composite layer can be changed by applying thermal treatments. The corrosion behavior was investigated via the potentiodynamic polarization test in a body-simulated environment. Here, the optimum corrosion resistance was obtained for the coating process condition at 500 V for 15 min in Ringer solution. This review has been summarized, aiming at the further development of PEO by producing more adequate titanium-base implants along with desired mechanical and biomedical features. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Systematic understanding of corrosion behavior of plasma electrolytic oxidation treated AZ31 magnesium alloy using a mouse model of subcutaneous implant.

    Science.gov (United States)

    Jang, Yongseok; Tan, Zongqing; Jurey, Chris; Collins, Boyce; Badve, Aditya; Dong, Zhongyun; Park, Chanhee; Kim, Cheol Sang; Sankar, Jagannathan; Yun, Yeoheung

    2014-12-01

    This study was conducted to identify the differences between corrosion rates, corrosion types, and corrosion products in different physiological environments for AZ31 magnesium alloy and plasma electrolytic oxidation (PEO) treated AZ31 magnesium alloy. In vitro and in vivo tests were performed in Hank's Balanced Salt Solution (HBSS) and mice for 12 weeks, respectively. The corrosion rates of both AZ31 magnesium alloy and PEO treated AZ31 magnesium alloy were calculated based on DC polarization curves, volume of hydrogen evolution, and the thickness of corrosion products formed on the surface. Micro X-ray computed tomography (Micro-CT), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) were used to analyze morphological and chemical characterizations of corrosion products. The results show that there is more severe localized corrosion after in vitro test in HBSS; however, the thicknesses of corrosion products formed on the surface for AZ31 magnesium alloy and PEO treated AZ31 magnesium alloy in vivo were about 40% thicker than the thickness of corrosion products generated in vitro. The ratio of Ca and P (Ca/P) in the corrosion products also differed. The Ca deficient region and higher content of Al in corrosion product than AZ31 magnesium alloy were identified after in vivo test in contrast with the result of in vitro test. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Understanding corrosion behavior of Mg-Zn-Ca alloys from subcutaneous mouse model: effect of Zn element concentration and plasma electrolytic oxidation.

    Science.gov (United States)

    Jang, Yongseok; Tan, Zongqing; Jurey, Chris; Xu, Zhigang; Dong, Zhongyun; Collins, Boyce; Yun, Yeoheung; Sankar, Jagannathan

    2015-03-01

    Mg-Zn-Ca alloys are considered as suitable biodegradable metallic implants because of their biocompatibility and proper physical properties. In this study, we investigated the effect of Zn concentration of Mg-xZn-0.3Ca (x=1, 3 and 5wt.%) alloys and surface modification by plasma electrolytic oxidation (PEO) on corrosion behavior in in vivo environment in terms of microstructure, corrosion rate, types of corrosion, and corrosion product formation. Microstructure analysis of alloys and morphological characterization of corrosion products were conducted using x-ray computed tomography (micro-CT) and scanning electron microscopy (SEM). Elemental composition and crystal structure of corrosion products were determined using x-ray diffraction (XRD) and electron dispersive x-ray spectroscopy (EDX). The results show that 1) as-cast Mg-xZn-0.3Ca alloys are composed of Mg matrix and a secondary phase of Ca2Mg6Zn3 formed along grain boundaries, 2) the corrosion rate of Mg-xZn-0.3Ca alloys increases with increasing concentration of Zn in the alloy, 3) corrosion rates of alloys treated by PEO sample are decreased in in vivo environment, and 4) the corrosion products of these alloys after in vivo tests are identified as brucite (Mg(OH)2), hydroxyapatite (Ca10(PO4)6(OH)2), and magnesite (MgCO3·3H2O). Copyright © 2014 Elsevier B.V. All rights reserved.

  19. An investigation into the mechanical and tribological properties of plasma electrolytic oxidation and hard-anodized coatings on 6082 aluminum alloy

    International Nuclear Information System (INIS)

    Malayoglu, Ugur; Tekin, Kadir C.; Malayoglu, Ufuk; Shrestha, Suman

    2011-01-01

    Highlights: → Mechanical properties of PEO and anodised coatings were studied using ultra-micro hardness tester. → Elastic modulus and hardness of the PEO coating were found much higher than those of the anodised coating. → Improved sliding wear of PEO coating is due to presence of hard α and γ-Al 2 O 3 phases. - Abstract: A ceramic coating on AA6082 aluminum alloy prepared by plasma electrolytic oxidation (PEO) has been studied and compared against a sulphuric acid hard-anodized coating on the same alloy. Surface morphology and microstructures of the coatings have been examined by scanning electron microscopy. X-ray diffraction is used to determine the phase composition of the coatings. The adhesion strength of the coatings has been evaluated using a scratch test method. The coating's mechanical properties such elastic modulus and hardness data have been generated using a dynamic ultra-microhardness tester. Sliding wear tests with different loading rates are performed on the coatings in order to assess their wear resistance. Test results show that the PEO treated samples exhibit significantly better mechanical properties compared to hard anodized samples. The elastic modulus and hardness of the PEO coating are 2-3 times greater than of the hard anodized coating and subsequently, an improved wear resistance of the PEO coating has been achieved. The mechanical properties of the coatings and their relations to their tribological performance are discussed.

  20. Scan-Mode Atmospheric-Pressure Plasma Jet Processed Reduced Graphene Oxides for Quasi-Solid-State Gel-Electrolyte Supercapacitors

    Directory of Open Access Journals (Sweden)

    Aliyah R. Hsu

    2018-01-01

    Full Text Available A scanning atmospheric-pressure plasma jet (APPJ is essential for high-throughput large-area and roll-to-roll processes. In this study, we evaluate scan-mode APPJ for processing reduced graphene oxides (rGOs that are used as the electrodes of quasi-solid-state gel-electrolyte supercapacitors. rGO nanoflakes are mixed with ethyl cellulose (EC and terpineol to form pastes for screen-printing. After screen-printing the pastes on carbon cloth, a DC-pulse nitrogen APPJ is used to process the pastes in the scan mode. The maximal temperature attained is ~550 °C with a thermal influence duration of ~10 s per scan. The pastes are scanned by APPJ for 0, 1, 3 and 5 times. X-ray photoelectron spectroscopy (XPS indicates the reduction of C-O binding content as the number of scan increases, suggesting the oxidation/decomposition of EC. The areal capacitance increases and then decreases as the number of scan increases; the best achieved areal capacitance is 15.93 mF/cm2 with one APPJ scan, in comparison to 4.38 mF/cm2 without APPJ processing. The capacitance retention rate of the supercapacitor with the best performance is ~93% after a 1000-cycle cyclic voltammetry (CV test. The optimal number of APPJ scans should enable the proper removal of inactive EC and improved wettability while minimizing the damage caused to rGOs by nitrogen APPJ processing.

  1. Electrolytes for solid oxide fuel cells

    Science.gov (United States)

    Fergus, Jeffrey W.

    The high operating temperature of solid oxide fuel cells (SOFCs), as compared to polymer electrolyte membrane fuel cells (PEMFCs), improves tolerance to impurities in the fuel, but also creates challenges in the development of suitable materials for the various fuel cell components. In response to these challenges, intermediate temperature solid oxide fuel cells (IT-SOFCs) are being developed to reduce high-temperature material requirements, which will extend useful lifetime, improve durability and reduce cost, while maintaining good fuel flexibility. A major challenge in reducing the operating temperature of SOFCs is the development of solid electrolyte materials with sufficient conductivity to maintain acceptably low ohmic losses during operation. In this paper, solid electrolytes being developed for solid oxide fuel cells, including zirconia-, ceria- and lanthanum gallate-based materials, are reviewed and compared. The focus is on the conductivity, but other issues, such as compatibility with electrode materials, are also discussed.

  2. Electrolytes for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Fergus, Jeffrey W. [Auburn University, Materials Research and Education Center, 275 Wilmore Laboratories, Auburn, AL 36849 (United States)

    2006-11-08

    The high operating temperature of solid oxide fuel cells (SOFCs), as compared to polymer electrolyte membrane fuel cells (PEMFCs), improves tolerance to impurities in the fuel, but also creates challenges in the development of suitable materials for the various fuel cell components. In response to these challenges, intermediate temperature solid oxide fuel cells (IT-SOFCs) are being developed to reduce high-temperature material requirements, which will extend useful lifetime, improve durability and reduce cost, while maintaining good fuel flexibility. A major challenge in reducing the operating temperature of SOFCs is the development of solid electrolyte materials with sufficient conductivity to maintain acceptably low ohmic losses during operation. In this paper, solid electrolytes being developed for solid oxide fuel cells, including zirconia-, ceria- and lanthanum gallate-based materials, are reviewed and compared. The focus is on the conductivity, but other issues, such as compatibility with electrode materials, are also discussed. (author)

  3. Structural, photoluminescent and photocatalytic properties of TiO{sub 2}:Eu{sup 3+} coatings formed by plasma electrolytic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Stojadinović, Stevan, E-mail: sstevan@ff.bg.ac.rs [University of Belgrade, Faculty of Physics, Studentski trg 12–16, Belgrade 11000 (Serbia); Radić, Nenad; Grbić, Boško [University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Department of Catalysis and Chemical Engineering, Njegoševa 12, Belgrade 11000 (Serbia); Maletić, Slavica [University of Belgrade, Faculty of Physics, Studentski trg 12–16, Belgrade 11000 (Serbia); Stefanov, Plamen [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Block 11, Sofia 1113 (Bulgaria); Pačevski, Aleksandar [University of Belgrade, Faculty of Mining and Geology, Đušina 7, 11000 Belgrade (Serbia); Vasilić, Rastko [University of Belgrade, Faculty of Physics, Studentski trg 12–16, Belgrade 11000 (Serbia)

    2016-05-01

    Graphical abstract: - Highlights: • TiO{sub 2}:Eu{sup 3+} coatings are formed by plasma electrolytic oxidation (PEO). • Photoluminescence is related to transitions of Eu{sup 3+} from level {sup 5}D{sub 0} to levels {sup 7}F{sub J}. • Eu{sup 3+} ions occupy non-inversion symmetry sites in the coatings. • PEO time is an important factor affecting photocatalytic activity. - Abstract: In this paper, we used plasma electrolytic oxidation (PEO) of titanium in water solution containing 10 g/L Na{sub 3}PO{sub 4}·12H{sub 2}O + 2 g/L Eu{sub 2}O{sub 3} powder for preparation of TiO{sub 2}:Eu{sup 3+} coatings. The surfaces of obtained coatings exhibit a typical PEO porous structure. The energy dispersive X-ray spectroscopy analysis showed that the coatings are mainly composed of Ti, O, P, and Eu; it is observed that Eu content in the coatings increases with PEO time. The X-ray diffraction analysis indicated that the coatings are crystallized and composed of anatase and rutile TiO{sub 2} phases, with anatase being the dominant one. X-ray photoelectron spectroscopy revealed that Ti 2p spin-orbit components of TiO{sub 2}:Eu{sup 3+} coatings are shifted towards higher binding energy, with respect to pure TiO{sub 2} coatings, suggesting that Eu{sup 3+} ions are incorporated into TiO{sub 2} lattice. Diffuse reflectance spectroscopy showed that TiO{sub 2}:Eu{sup 3+} coatings exhibit evident red shift with respect to the pure TiO{sub 2} coatings. Photoluminescence (PL) emission spectra of TiO{sub 2}:Eu{sup 3+} coatings are characterized by sharp emission bands in orange–red region ascribed to f–f transitions of Eu{sup 3+} ions from excited level {sup 5}D{sub 0} to lower levels {sup 7}F{sub J} (J = 0, 1, 2, 3, and 4). The excitation PL spectra of TiO{sub 2}:Eu{sup 3+} coatings can be divided into two regions: the broad band region from 250 nm to 350 nm associated with charge transfer state of Eu{sup 3+} and the series of sharp peaks in the range from 350 nm to 550 nm

  4. Plasma electrolytic polishing of metalized carbon fibers

    Directory of Open Access Journals (Sweden)

    Falko Böttger-Hiller

    2016-02-01

    Full Text Available Efficient lightweight structures require intelligent materials that meet versatile functions. Especially, carbon-fiber-reinforced polymers (CFRPs are gaining relevance. Their increasing use aims at reducing energy consumption in many applications. CFRPs are generally very light in weight, while at the same time being extremely stiff and strong (specific strength: CFRPs: 1.3 Nm kg–1, steel: 0.27 Nm kg–1; specific stiffness: CFRPs: 100 Nm kg–1, steel: 25 Nm kg–1. To increase performance and especially functionality of CFRPs, the integration of microelectronic components into CFRP parts is aspired. The functionalization by sensors, actuators and electronics can enable a high lightweight factor and a new level of failure-safety. The integration of microelectronic components for this purpose requires a working procedure to provide electrical contacts for a reliable connection to energy supply and data interfaces. To overcome this challenge, metalized carbon fibers are used. Metalized fibers are, similar to the usual reinforcing fibers, able to be soldered and therefore easy to incorporate into CFRPs. Unfortunately, metalized fibers have to be pre-treated by flux-agents. Until now, there is no flux which is suitable for mass production without destroying the polymer of the CFRP. The process of plasma electrolytic polishing (PeP could be an option, but is so far not available for copper. Thus, in this study, plasma electrolytic polishing is transferred to copper and its alloys. To achieve this, electrolytic parameters as well as the electrical setup are adapted. It can be observed that the gloss and roughness can be adjusted by means of this procedure. Finally, plasma electrolytic polishing is used to treat thin copper layers on carbon fibers.

  5. TEM analysis and wear resistance of the ceramic coatings on Q235 steel prepared by hybrid method of hot-dipping aluminum and plasma electrolytic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Lu Lihong [State Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Science and Research Department, Chinese People' s Armed Police Academy, Langfang 065000 (China); Zhang Jingwu [State Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Shen Dejiu, E-mail: sdj217@ysu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Wu Lailei; Jiang Guirong [State Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Li Liang [State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084 (China)

    2012-01-25

    Highlights: Black-Right-Pointing-Pointer Transmission electron microscopy (TEM) was firstly used to analyze the phase composition of the ceramic coatings. Black-Right-Pointing-Pointer The phase composition of the ceramic coatings is mainly amorphous phase and crystal Al{sub 2}O{sub 3} oxides. Black-Right-Pointing-Pointer The cross-section micro-hardness of the treated samples was investigated, the hardness of the ceramic coatings is about HV1300. Black-Right-Pointing-Pointer The wear resistance of the PEO samples is about 3 times higher than that of the heat treated 45 steel. - Abstract: The hybrid method of PEO and hot-dipping aluminum (HDA) was employed to deposit composite ceramic coatings on the surface of Q235 steel. The composition of the composite coatings was investigated with X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The cross-section microstructure and micro-hardness of the treated specimens were investigated and analyzed with scanning electron microscopy (SEM) and microscopic hardness meter (MHM), respectively. The wear resistance of the ceramic coatings was investigated by a self-made rubbing wear testing machine. The results indicate that metallurgical bonding can be observed between the ceramic coatings and the steel substrate. There are many micro-pores and micro-cracks, which act as the discharge channels and result of quick and non-uniform cooling of melted sections in the plasma electrolytic oxidation ceramic coatings. The phase composition of the ceramic coatings is mainly composed of amorphous phase and crystal Al{sub 2}O{sub 3} oxides. The crystal Al{sub 2}O{sub 3} phase includes {kappa}-Al{sub 2}O{sub 3}, {theta}-Al{sub 2}O{sub 3} and {beta}-Al{sub 2}O{sub 3}. The grain size of the {kappa}-Al{sub 2}O{sub 3} crystal is quite non-uniform. The hardness of the ceramic coatings is about HV1300 and 10 times higher than that of the Q235 substrate, which was favorable to the better wear resistance of the ceramic

  6. Electrolytic recovery of uranium oxides

    International Nuclear Information System (INIS)

    Gurr, W.R.

    1979-01-01

    A method is described for extracting uranium oxide from a solution of one or more uranium compounds, e.g. leach liquors, comprising subjecting the solution to electrolysis utilizing a high current density, e.g. 500 to 4000 amp/m 2 , whereby uranium oxide is formed at the cathode and is recovered. The method is particularly suited to a continuous process using a rotating cathode cell. (author)

  7. Plasma electrolytic liquefaction of cellulosic biomass

    Science.gov (United States)

    Dingliang, TANG; Xianhui, ZHANG; Si-ze, YANG

    2018-04-01

    In this paper, the rapid liquefaction of a corncob was achieved by plasma electrolysis, providing a new method for cellulosic biomass liquefaction. The liquefaction rate of the corncob was 95% after 5 min with polyethylene glycol and glycerol as the liquefying agent. The experiments not only showed that H+ ions catalyzed the liquefaction of the corncob, but also that using accelerated H+ ions, which were accelerated by an electric field, could effectively improve the liquefaction efficiency. There was an obvious discharge phenomenon, in which the generated radicals efficiently heated the solution and liquefied the biomass, in the process of plasma electrolytic liquefaction. Finally, the optimum parameters of the corncob liquefaction were obtained by experimentation, and the liquefaction products were analyzed.

  8. Physicochemistry of the plasma-electrolyte solution interface

    International Nuclear Information System (INIS)

    Chen Qiang; Saito, Kenji; Takemura, Yu-ichiro; Shirai, Hajime

    2008-01-01

    The atmospheric rf plasma discharge was successfully investigated using NaOH or HCl electrolyte solutions as a counter electrode at different pH values. The emission intensities of solution components, self bias, and electron density strongly depend on the pH value of electrolyte. An addition of ethanol to the electrolyte solutions enhanced the dehydration, which markedly promoted the emissions of solution components as well as electrons from the solution. An acidification of the solution was always observed after the plasma exposure and two coexisting mechanisms were proposed to give a reasonable interpretation. The plasma-electrolyte interface was discussed based on a model of hydrogen cycle

  9. Operating mechanisms of electrolytes in magnesium ion batteries: chemical equilibrium, magnesium deposition, and electrolyte oxidation.

    Science.gov (United States)

    Kim, Dong Young; Lim, Younhee; Roy, Basab; Ryu, Young-Gyoon; Lee, Seok-Soo

    2014-12-21

    Since the early nineties there have been a number of reports on the experimental development of Mg electrolytes based on organo/amide-magnesium chlorides and their transmetalations. However, there are no theoretical papers describing the underlying operating mechanisms of Mg electrolytes, and there is no clear understanding of these mechanisms. We have therefore attempted to clarify the operating mechanisms of Mg electrolytes by studying the characteristics of Mg complexes, solvation, chemical equilibrium, Mg-deposition processes, electrolyte-oxidation processes, and oxidative degradation mechanism of RMgCl-based electrolytes, using ab initio calculations. The formation and solvation energies of Mg complexes highly depend on the characteristics of R groups. Thus, changes in R groups of RMgCl lead to changes in the equilibrium position and the electrochemical reduction and oxidation pathways and energies. We first provide a methodological scheme for calculating Mg reduction potential values in non-aqueous electrolytes and electrochemical windows. We also describe a strategy for designing Mg electrolytes to maximize the electrochemical windows and oxidative stabilities. These results will be useful not only for designing improved Mg electrolytes, but also for developing new electrolytes in the future.

  10. Reference Values for Plasma Electrolytes and Urea in Nigerian ...

    African Journals Online (AJOL)

    Reference values for plasma electrolytes and urea have been defined for Nigerian children and adolescents residing in Abeokuta and its environs, a location in southern Nigeria, by estimating plasma sodium, potassium bicarbonate and urea concentrations in a reference population. The study group comprised three ...

  11. Low temperature solid oxide electrolytes (LT-SOE): A review

    Science.gov (United States)

    Singh, B.; Ghosh, S.; Aich, S.; Roy, B.

    2017-01-01

    Low temperature solid oxide fuel cell (LT-SOFC) can be a source of power for vehicles, online grid, and at the same time reduce system cost, offer high reliability, and fast start-up. A huge amount of research work, as evident from the literature has been conducted for the enhancement of the ionic conductivity of LT electrolytes in the last few years. The basic conduction mechanisms, advantages and disadvantages of different LT oxide ion conducting electrolytes {BIMEVOX systems, bilayer systems including doped cerium oxide/stabilised bismuth oxide and YSZ/DCO}, mixed ion conducting electrolytes {doped cerium oxides/alkali metal carbonate composites}, and proton conducting electrolytes {doped and undoped BaCeO3, BaZrO3, etc.} are discussed here based on the recent research articles. Effect of various material aspects (composition, doping, layer thickness, etc.), fabrication methods (to achieve different microstructures and particle size), design related strategies (interlayer, sintering aid etc.), characterization temperature & environment on the conductivity of the electrolytes and performance of the fuel cells made from these electrolytes are shown in tabular form and discussed. The conductivity of the electrolytes and performance of the corresponding fuel cells are compared. Other applications of the electrolytes are mentioned. A few considerations regarding the future prospects are pointed.

  12. Pulsed nanocrystalline plasma electrolytic boriding as a novel ...

    Indian Academy of Sciences (India)

    Potentiodynamic polarization and electrochemical impedance spectroscopy were employed to test borided CP-Ti, treated by a relatively new method called pulsed plasma electrolytic boriding. The results show excellent corrosion resistance for modified CP-Ti. The effect of frequency and duty cycle of pulsed current was ...

  13. Pulsed nanocrystalline plasma electrolytic boriding as a novel ...

    Indian Academy of Sciences (India)

    WINTEC

    borided CP-Ti, treated by a relatively new method called pulsed plasma electrolytic boriding. The results ... ratio, high stiffness and strength (Donachie 2000; Lutjer- ing and Albrecht ..... both direct current and a.c. techniques. Although the main ...

  14. Preparation and characterization of polyindole - iron oxide nanocomposite electrolyte

    International Nuclear Information System (INIS)

    Rajasudha, G.; Stephen, A.; Narayanan, V.

    2009-01-01

    Full text: A novel polyindole-iron oxide containing LiClO 4 solid polymer electrolyte has been prepared. The diverse property of magnetic nanoparticle has elicited wide interest from the point of view of technological applications. Their properties are known to be strongly dependent on size, anisotropy and inter particle interactions. The proton conducting materials has received considerable attention as electrolyte materials in technological applications such as fuel cells, sensors and electrochromic display. In this work, polyindole-iron oxide nanocomposite containing LiClO 4 was prepared by in situ polymerization. The indole was polymerized in the presence of iron oxide, using ammonium peroxy disulphate as an oxidizing agent. The polyindole-iron oxide nanocomposite was characterized by XRD, IR, SEM, TGA and TEM. The iron oxide nano particles was incorporated into polyindole and was confirmed by XRD and Fourier transform infrared (FTIR) spectroscopy. The surface Morphology and thermal stability were studied by thermogravimetric analysis (TGA) and SEM respectively. The ionic conductivity of polyindole electrolyte was analyzed from impedance spectrum. The prepared polyindole-iron oxide nanocomposite could be used as solid electrolyte in lithium ion batteries

  15. Characteristics of MOX dissolution with silver mediated electrolytic oxidation method

    Energy Technology Data Exchange (ETDEWEB)

    Umeda, Miki; Nakazaki, Masato; Kida, Takashi; Sato, Kenji; Kato, Tadahito; Kihara, Takehiro; Sugikawa, Susumu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    MOX dissolution with silver mediated electrolytic oxidation method is to be applied to the preparation of plutonium nitrate solution to be used for criticality safety experiments at Nuclear Fuel Cycle Safety Engineering Research Facility (NUCEF). Silver mediated electrolytic oxidation method uses the strong oxidisation ability of Ag(II) ion. This method is though to be effective for the dissolution of MOX, which is difficult to be dissolved with nitric acid. In this paper, the results of experiments on dissolution with 100 g of MOX are described. It was confirmed from the results that the MOX powder to be used at NUCEF was completely dissolved by silver mediated electrolytic oxidation method and that Pu(VI) ion in the obtained solution was reduced to tetravalent by means of NO{sub 2} purging. (author)

  16. Solid polymer electrolyte composite membrane comprising plasma etched porous support

    Science.gov (United States)

    Liu, Han; LaConti, Anthony B.

    2010-10-05

    A solid polymer electrolyte composite membrane and method of manufacturing the same. According to one embodiment, the composite membrane comprises a rigid, non-electrically-conducting support, the support preferably being a sheet of polyimide having a thickness of about 7.5 to 15 microns. The support has a plurality of cylindrical pores extending perpendicularly between opposing top and bottom surfaces of the support. The pores, which preferably have a diameter of about 0.1 to 5 microns, are made by plasma etching and preferably are arranged in a defined pattern, for example, with fewer pores located in areas of high membrane stress and more pores located in areas of low membrane stress. The pores are filled with a first solid polymer electrolyte, such as a perfluorosulfonic acid (PFSA) polymer. A second solid polymer electrolyte, which may be the same as or different than the first solid polymer electrolyte, may be deposited over the top and/or bottom of the first solid polymer electrolyte.

  17. Electrochemical oxidation of quaternary ammonium electrolytes : Unexpected side reactions in organic electrochemistry

    NARCIS (Netherlands)

    Nouri Nigjeh, Eslam; de Vries, Marcel; Bruins, Andries P.; Bischoff, Rainer; Permentier, Hjalmar P.

    Quaternary ammonium salts are among the most widely used electrolytes in organic electrochemistry, but there is little known about their unwanted side oxidation reactions. We have, therefore, studied the constant potential oxidation products of quaternary ammonium electrolytes using mass

  18. Permeability and Microstructure of Suspension Plasma-Sprayed YSZ Electrolytes for SOFCs on Various Substrates

    Science.gov (United States)

    Marr, Michael; Kesler, Olivera

    2012-12-01

    Yttria-stabilized zirconia electrolyte coatings for solid oxide fuel cells were deposited by suspension plasma spraying using a range of spray conditions and a variety of substrates, including finely structured porous stainless steel disks and cathode layers on stainless steel supports. Electrolyte permeability values and trends were found to be highly dependent on which substrate was used. The most gas-tight electrolyte coatings were those deposited directly on the porous metal disks. With this substrate, permeability was reduced by increasing the torch power and reducing the stand-off distance to produce dense coating microstructures. On the substrates with cathodes, electrolyte permeability was reduced by increasing the stand-off distance, which reduced the formation of segmentation cracks and regions of aligned and concentrated porosity. The formation mechanisms of the various permeability-related coating features are discussed and strategies for reducing permeability are presented. The dependences of electrolyte deposition efficiency and surface roughness on process conditions and substrate properties are also presented.

  19. Influence of process parameters on plasma electrolytic surface treatment of tantalum for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Sowa, Maciej, E-mail: maciej.sowa@polsl.pl [Faculty of Chemistry, Silesian University of Technology, B. Krzywoustego Street 6, 44-100 Gliwice (Poland); Woszczak, Maja; Kazek-Kęsik, Alicja [Faculty of Chemistry, Silesian University of Technology, B. Krzywoustego Street 6, 44-100 Gliwice (Poland); Dercz, Grzegorz [Institute of Materials Science, University of Silesia, 75 Pułku Piechoty Street 1A, 41-500 Chorzów (Poland); Korotin, Danila M. [M.N. Mikheev Institute of Metal Physics of the Ural Branch of Russian Academy of Sciences, S. Kovalevskoi Street 18, 620990 Yekaterinburg (Russian Federation); Institute of Physics and Technology, Ural Federal University, Mira Street 19, 620002 Yekaterinburg (Russian Federation); Zhidkov, Ivan S. [Institute of Physics and Technology, Ural Federal University, Mira Street 19, 620002 Yekaterinburg (Russian Federation); Kurmaev, Ernst Z. [M.N. Mikheev Institute of Metal Physics of the Ural Branch of Russian Academy of Sciences, S. Kovalevskoi Street 18, 620990 Yekaterinburg (Russian Federation); Institute of Physics and Technology, Ural Federal University, Mira Street 19, 620002 Yekaterinburg (Russian Federation); Cholakh, Seif O. [Institute of Physics and Technology, Ural Federal University, Mira Street 19, 620002 Yekaterinburg (Russian Federation); Basiaga, Marcin [Faculty of Biomedical Engineering, Silesian University of Technology, Gen. de Gaulle’a Street 66, 41-800 Zabrze (Poland); Simka, Wojciech, E-mail: wojciech.simka@polsl.pl [Faculty of Chemistry, Silesian University of Technology, B. Krzywoustego Street 6, 44-100 Gliwice (Poland)

    2017-06-15

    Highlights: • 2-step plasma electrolytic oxidation (PEO) of tantalum was investigated. • PEO coatings surface composition were reflected by the composition of anodizing baths. • Hydrophobic surfaces were obtained from acetate and formate containing baths. • Bioactive phases were identified. - Abstract: This work aims to quantify the effect of anodization voltage and electrolyte composition used during DC plasma electrolytic oxidation (PEO), operated as a 2-step process, on the surface properties of the resulting oxide coatings on tantalum. The first step consisted of galvanostatic anodization (150 mA cm{sup −2}) of the tantalum workpiece up to several limiting voltages (200, 300, 400 and 500 V). After attaining the limiting voltage, the process was switched to voltage control, which resulted in a gradual decrease of the anodic current density. The anodic treatment was realized in a 0.5 M Ca(H{sub 2}PO{sub 2}){sub 2} solution, which was then modified by the addition of 1.15 M Ca(HCOO){sub 2} as well as 1.15 M and 1.5 M Mg(CH{sub 3}COO){sub 2}. The increasing voltage of anodization led to the formation of thicker coatings, with larger pores and enriched with electrolytes species to a higher extent. The solutions containing HCOO{sup −} and CH{sub 3}COO{sup −} ions caused the formation of coatings which were slightly hydrophobic (high contact angle). In the case of the samples anodized up to 500 V, scattered crystalline deposits were observed. Bioactive phases, such as hydroxyapatite, were detected in the treated oxide coatings by XRD and XPS.

  20. Solid oxide fuel cells with bi-layered electrolyte structure

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xinge; Robertson, Mark; Deces-Petit, Cyrille; Xie, Yongsong; Hui, Rob; Qu, Wei; Kesler, Olivera; Maric, Radenka; Ghosh, Dave [Institute for Fuel Cell Innovation, National Research Council Canada, 4250 Wesbrook Mall, Vancouver, B.C. V6T 1W5 (Canada)

    2008-01-10

    In this work, we have developed solid oxide fuel cells with a bi-layered electrolyte of 2 {mu}m SSZ and 4 {mu}m SDC using tape casting, screen printing, and co-firing processes. The cell reached power densities of 0.54 W cm{sup -2} at 650 C and 0.85 W cm{sup -2} at 700 C, with open circuit voltage (OCV) values larger than 1.02 V. The electrical leaking between anode and cathode through an SDC electrolyte has been blocked in the bi-layered electrolyte structure. However, both the electrolyte resistance (R{sub el}) and electrode polarization resistance (R{sub p,a+c}) increased in comparison to cells with single-layered SDC electrolytes. The formation of a solid solution of (Ce, Zr)O{sub 2-x} during sintering process and the flaws in the bi-layered electrolyte structure seem to be the main causes for the increase in the R{sub el} value (0.32 {omega} cm{sup 2}) at 650 C, which is almost one order of magnitude higher than the calculated value. (author)

  1. Raising the Corrosion Resistance of Low-Carbon Steels by Electrolytic-Plasma Saturation with Nitrogen and Carbon

    Science.gov (United States)

    Kusmanov, S. A.; Grishina, E. P.; Belkin, P. N.; Kusmanova, Yu. V.; Kudryakova, N. O.

    2017-05-01

    Structural features of the external oxide layer and internal nitrided, carbonitrided and carburized layers in steels 10, 20 and St3 produced by the method of electrolytic plasma treatment are studied. Specimens of the steels are tested for corrosion in a naturally aerated 1-N solution of sodium chloride. The condition of the metal/sodium chloride solution interface is studied by the method of electrochemical impedance spectroscopy. It is shown that the corrosion resistance of low-carbon steels can be raised by anode electrolytic-plasma saturation with nitrogen and carbon. Recommendations are given on the choice of carbonitriding modes for structural steels.

  2. Synthesis and evaluation of tetracycline encapsulated in poly (lactic-co-glycolic acid) on porous titania formed by using plasma electrolytic oxidation

    International Nuclear Information System (INIS)

    Moon, Seung-Kyun; Kang, Min-Kyung; Im, Su-Yeon; Kim, Kyoung-Nam; Kwon, Jae-Sung

    2012-01-01

    Despite a relatively high success rate in treating bacterial infection, it is still the major complication following dental implant surgery. Many attempts have been carried out to produce antibacterial effects on implant metals, and there have included coating of antibiotics encapsulated in polymers by using the electro-spray deposition (ESD) method. However, remnant polymer following full release of the medication, resulting in delamination between the surface layers of the implant and newly formed bone, has been a major problem. Hence, different organic polymer of poly (lactic-co-glycolic acid) (PLGA) were used in this study. Commercially pure titanium was used in this experiment and was anodized to improve biocompatibility. The PLGA was dissolved in dichloromethane along with tetracycline, and the fabricated tetracycline encapsulated in PLGA was then coated on a porous oxide layer of titanium by using the ESD method. The surface characteristics were analyzed, and the antibacterial effects of the specimen were assessed using bacteria of Staphylococcus aereus. Finally, the cytotoxicity and cell proliferation on the surface was evaluated. The results indicated that such titanium formed by a coating of tetracycline encapsulated in PLGA on a porous titania structure exhibited antibacterial effects and was both non-cytotoxic and biocompatible. Also, PLGA seemed to be an ideal candidate as the medium to encapsulate antibiotics or other medications such as growth factors due to its rapid degradation compared to other organic polymer. From this experiment, we conclude that porous titania coated by tetracycline encapsulated in PLGA by using ESD method is appropriate for use in dental or medical implants to prevent the major complication of surgery, infection.

  3. Synthesis and evaluation of tetracycline encapsulated in poly (lactic-co-glycolic acid) on porous titania formed by using plasma electrolytic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Seung-Kyun; Kang, Min-Kyung; Im, Su-Yeon; Kim, Kyoung-Nam; Kwon, Jae-Sung [Yonsei University, Seoul (Korea, Republic of)

    2012-03-15

    Despite a relatively high success rate in treating bacterial infection, it is still the major complication following dental implant surgery. Many attempts have been carried out to produce antibacterial effects on implant metals, and there have included coating of antibiotics encapsulated in polymers by using the electro-spray deposition (ESD) method. However, remnant polymer following full release of the medication, resulting in delamination between the surface layers of the implant and newly formed bone, has been a major problem. Hence, different organic polymer of poly (lactic-co-glycolic acid) (PLGA) were used in this study. Commercially pure titanium was used in this experiment and was anodized to improve biocompatibility. The PLGA was dissolved in dichloromethane along with tetracycline, and the fabricated tetracycline encapsulated in PLGA was then coated on a porous oxide layer of titanium by using the ESD method. The surface characteristics were analyzed, and the antibacterial effects of the specimen were assessed using bacteria of Staphylococcus aereus. Finally, the cytotoxicity and cell proliferation on the surface was evaluated. The results indicated that such titanium formed by a coating of tetracycline encapsulated in PLGA on a porous titania structure exhibited antibacterial effects and was both non-cytotoxic and biocompatible. Also, PLGA seemed to be an ideal candidate as the medium to encapsulate antibiotics or other medications such as growth factors due to its rapid degradation compared to other organic polymer. From this experiment, we conclude that porous titania coated by tetracycline encapsulated in PLGA by using ESD method is appropriate for use in dental or medical implants to prevent the major complication of surgery, infection.

  4. Hydroxyl radical production in plasma electrolysis with KOH electrolyte solution

    Energy Technology Data Exchange (ETDEWEB)

    Saksono, Nelson; Febiyanti, Irine Ayu, E-mail: irine.ayu41@ui.ac.id; Utami, Nissa; Ibrahim [Department of Chemical Engineering, Universitas Indonesia, Depok 16424, Indonesia Phone: +62217863516, Fax: +62217863515 (Indonesia)

    2015-12-29

    Plasma electrolysis is an effective technology for producing hydroxyl radical (•OH). This method can be used for waste degradation process. This study was conducted to obtain the influence of applied voltage, electrolyte concentration, and anode depth in the plasma electrolysis system for producing hydroxyl radical. The materials of anode and cathode, respectively, were made from tungsten and stainless steel. KOH solution was used as the solution. Determination of hydroxyl radical production was done by measuring H{sub 2}O{sub 2} amount formed in plasma system using an iodometric titration method, while the electrical energy consumed was obtained by measuring the electrical current throughout the process. The highest hydroxyl radical production was 3.51 mmol reached with 237 kJ energy consumption in the power supply voltage 600 V, 0.02 M KOH, and 0.5 cm depth of anode.

  5. Microhardness of anodic aluminum oxide formed in an alkaline electrolyte

    Science.gov (United States)

    Kanygina, O. N.; Filyak, M. M.

    2017-04-01

    The microhardness of anodic aluminum oxide formed by anodizing of aluminum sheet in electrolyte on the basis of sodium hydroxide has been determined experimentally. The microhardness of the hard film/soft substrate system has been estimated by three approaches: indentation geometry (length of diagonals) in film surfaces, the sum of the hardnesses of the film and the surface with allowance for the indentation surface area and geometry, and with allowance for the indentation depth. It is demonstrated that the approach accounting for the indentation depth makes it possible to eliminate the influence of the substrate. It is established that the microhardness of the films formed in alkaline electrolytes is comparable with that formed in acid electrolytes.

  6. Evaluation of apatite silicates as solid oxide fuel cell electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Marrero-Lopez, D. [Dpto. de Fisica Aplicada I, Laboratorio de Materiales y Superficies (Unidad Asociada al C.S.I.C.), Universidad de Malaga, 29071 Malaga (Spain); Dpto. de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain); Martin-Sedeno, M.C.; Aranda, M.A.G. [Dpto. de Quimica Inorganica, Universidad Malaga, 29071 Malaga (Spain); Pena-Martinez, J. [Dpto. de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain); Instituto de Energias Renovables, Parque Tecnologico, Universidad de Castilla La Mancha, 02006 Albacete (Spain); Ruiz-Morales, J.C.; Nunez, P. [Dpto. de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain); Ramos-Barrado, J.R. [Dpto. de Fisica Aplicada I, Laboratorio de Materiales y Superficies (Unidad Asociada al C.S.I.C.), Universidad de Malaga, 29071 Malaga (Spain)

    2010-05-01

    Apatite-type silicates have been considered as promising electrolytes for Solid Oxide Fuel Cells (SOFC); however studies on the potential use of these materials in SOFC devices have received relatively little attention. The lanthanum silicate with composition La{sub 10}Si{sub 5.5}Al{sub 0.5}O{sub 26.75} has been evaluated as electrolyte with the electrode materials commonly used in SOFC, i.e. manganite, ferrite and cobaltite as cathode materials and NiO-CGO composite, chromium-manganite and Sr{sub 2}MgMoO{sub 6} as anode materials. Chemical compatibility, area-specific resistance and fuel cell studies have been performed. X-ray powder diffraction (XRPD) analysis did not reveal any trace of reaction products between the apatite electrolyte and most of the aforementioned electrode materials. However, the area-specific polarisation resistance (ASR) of these electrodes in contact with apatite electrolyte increased significantly with the sintering temperature, indicating reactivity at the electrolyte/electrode interface. On the other hand, the ASR values are significantly improved using a ceria buffer layer between the electrolyte and electrode materials to prevent reactivity. Maximum power densities of 195 and 65 mWcm{sup -2} were obtained at 850 and 700 C, respectively in H{sub 2} fuel, using an 1 mm-thick electrolyte, a NiO-Ce{sub 0.8}Gd{sub 0.2}O{sub 1.9} composite as anode and La{sub 0.6}Sr{sub 0.4}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} as cathode materials. This fuel cell was tested for 100 h in 5%H{sub 2}-Ar atmosphere showing stable performance. (author)

  7. Catalysed electrolytic metal oxide dissolution processes

    International Nuclear Information System (INIS)

    Machuron-Mandard, X.

    1994-01-01

    The hydrometallurgical processes designed for recovering valuable metals from mineral ores as well as industrial wastes usually require preliminary dissolution of inorganic compounds in aqueous media before extraction and purification steps. Unfortunately, most of the minerals concerned hardly or slowly dissolve in acidic or basic solutions. Metallic oxides, sulfides and silicates are among the materials most difficult to dissolve in aqueous solutions. They are also among the main minerals containing valuable metals. The redox properties of such materials sometimes permit to improve their dissolution by adding oxidizing or reducing species to the leaching solution, which leads to an increase in the dissolution rate. Moreover, limited amounts of redox promoters are required if the redox agent is regenerated continuously thanks to an electrochemical device. Nuclear applications of such concepts have been suggested since the dissolution of many actinide compounds (e.g., UO 2 , AmO 2 , PuC, PuN,...) is mainly based on redox reactions. In the 1980s, improvements of the plutonium dioxide dissolution process have been proposed on the basis of oxidation-reduction principles, which led a few years later to the design of industrial facilities (e.g., at Marcoule or at the french reprocessing plant of La Hague). General concepts and well-established results obtained in France at the Atomic Energy Commission (''Commissariat a l'Energie Atomique'') will be presented and will illustrate applications to industrial as well as analytical problems. (author)

  8. Failure analysis of electrolyte-supported solid oxide fuel cells

    Science.gov (United States)

    Fleischhauer, Felix; Tiefenauer, Andreas; Graule, Thomas; Danzer, Robert; Mai, Andreas; Kuebler, Jakob

    2014-07-01

    For solid oxide fuel cells (SOFCs) one key aspect is the structural integrity of the cell and hence its thermo mechanical long term behaviour. The present study investigates the failure mechanisms and the actual causes for fracture of electrolyte supported SOFCs which were run using the current μ-CHP system of Hexis AG, Winterthur - Switzerland under lab conditions or at customer sites for up to 40,000 h. In a first step several operated stacks were demounted for post-mortem inspection, followed by a fractographic evaluation of the failed cells. The respective findings are then set into a larger picture including an analysis of the present stresses acting on the cell like thermal and residual stresses and the measurements regarding the temperature dependent electrolyte strength. For all investigated stacks, the mechanical failure of individual cells can be attributed to locally acting bending loads, which rise due to an inhomogeneous and uneven contact between the metallic interconnect and the cell.

  9. Increasing Wear Resistance of Titanium Alloys by Anode Plasma Electrolytic Saturation with Interstitial Elements

    Science.gov (United States)

    Belkin, P. N.; Kusmanov, S. A.; Dyakov, I. G.; Silkin, S. A.; Smirnov, A. A.

    2017-05-01

    In our previous studies, we have shown that anode plasma electrolytic saturation of titanium alloys with nitrogen and carbon can improve their tribological properties. Obtained structure containing oxide layer and solid solution of diffused element in titanium promotes the enhancement of running-in ability and the decrease in the wear rate in some special cases. In this paper, further investigations are reported regarding the tribological properties of alpha- and beta-titanium alloys in wear test against hardened steel (50 HRC) disk using pin-on-disk geometry and balls of Al2O3 (6.25 mm in diameter) or bearing steel (9.6 mm in diameter) with ball-on-plate one and normal load from 5 to 209 N. Reproducible results were obtained under testing samples treated by means of the plasma electrolytic nitriding (PEN) with the mechanical removal of the oxide layer. Friction coefficient of nitrided samples is 0.5-0.9 which is somewhat higher than that for untreated one (0.48-0.75) during dry sliding against Al2O3 ball. An increase in the sliding speed results in the polishing of nitrided samples and reduction of their wear rate by 60 times. This result is obtained for 5 min at 850 °C using PEN in electrolyte containing 5 wt.% ammonia and 10 wt.% ammonium chloride followed by quenching in solution. Optical microscope was employed to assist in the evaluation of the wear behavior. Sizes of wear tracks were measured by profilometer TR200.

  10. Kinetics and mechanism of oxidation of carbidized electrolytic chromium coatings

    International Nuclear Information System (INIS)

    Arkharov, V.I.; Yar-Mukhamedov, Sh.Kh.

    1978-01-01

    Thermal stability carbidized electrolytic chromium coatings has been studied depending on the conditions of their formation; the specific features of the mechanism of oxidation at 1200 deg in an air atmosphere have been elucidated. It has been established that kinetics of high temperature oxidation of the coatings depends essentially on the conditions of their formation and on the composition of steel to which the coating is applied. It has been shown that two oxidation mechanisms are possible: by diffusion of the residual chromium through a carbide layer along the carbide grain boundaries outwards or, when there is no residual chromium, by chemical reaction of carbon combustion and oxidation of the liberated chromium. The comparison of oxidation kinetic curves of the samples of 38KhMYuA, 35KhGSA, and DI-22 steels with and without coating has shown that the coatings under study have a better protective effect on 38KhMYuA steel than on 35KhGSA, although without coating oxidability of the first steel is higher than that of the second

  11. Plasma Membranes Modified by Plasma Treatment or Deposition as Solid Electrolytes for Potential Application in Solid Alkaline Fuel Cells

    Science.gov (United States)

    Reinholdt, Marc; Ilie, Alina; Roualdès, Stéphanie; Frugier, Jérémy; Schieda, Mauricio; Coutanceau, Christophe; Martemianov, Serguei; Flaud, Valérie; Beche, Eric; Durand, Jean

    2012-01-01

    In the highly competitive market of fuel cells, solid alkaline fuel cells using liquid fuel (such as cheap, non-toxic and non-valorized glycerol) and not requiring noble metal as catalyst seem quite promising. One of the main hurdles for emergence of such a technology is the development of a hydroxide-conducting membrane characterized by both high conductivity and low fuel permeability. Plasma treatments can enable to positively tune the main fuel cell membrane requirements. In this work, commercial ADP-Morgane® fluorinated polymer membranes and a new brand of cross-linked poly(aryl-ether) polymer membranes, named AMELI-32®, both containing quaternary ammonium functionalities, have been modified by argon plasma treatment or triallylamine-based plasma deposit. Under the concomitant etching/cross-linking/oxidation effects inherent to the plasma modification, transport properties (ionic exchange capacity, water uptake, ionic conductivity and fuel retention) of membranes have been improved. Consequently, using plasma modified ADP-Morgane® membrane as electrolyte in a solid alkaline fuel cell operating with glycerol as fuel has allowed increasing the maximum power density by a factor 3 when compared to the untreated membrane. PMID:24958295

  12. Plasma membranes modified by plasma treatment or deposition as solid electrolytes for potential application in solid alkaline fuel cells.

    Science.gov (United States)

    Reinholdt, Marc; Ilie, Alina; Roualdès, Stéphanie; Frugier, Jérémy; Schieda, Mauricio; Coutanceau, Christophe; Martemianov, Serguei; Flaud, Valérie; Beche, Eric; Durand, Jean

    2012-07-30

    In the highly competitive market of fuel cells, solid alkaline fuel cells using liquid fuel (such as cheap, non-toxic and non-valorized glycerol) and not requiring noble metal as catalyst seem quite promising. One of the main hurdles for emergence of such a technology is the development of a hydroxide-conducting membrane characterized by both high conductivity and low fuel permeability. Plasma treatments can enable to positively tune the main fuel cell membrane requirements. In this work, commercial ADP-Morgane® fluorinated polymer membranes and a new brand of cross-linked poly(aryl-ether) polymer membranes, named AMELI-32®, both containing quaternary ammonium functionalities, have been modified by argon plasma treatment or triallylamine-based plasma deposit. Under the concomitant etching/cross-linking/oxidation effects inherent to the plasma modification, transport properties (ionic exchange capacity, water uptake, ionic conductivity and fuel retention) of membranes have been improved. Consequently, using plasma modified ADP-Morgane® membrane as electrolyte in a solid alkaline fuel cell operating with glycerol as fuel has allowed increasing the maximum power density by a factor 3 when compared to the untreated membrane.

  13. Performance limitations of polymer electrolytes based on ethylene oxide polymers

    International Nuclear Information System (INIS)

    Buriez, Olivier; Han, Yong Bong; Hou, Jun; Kerr, John B.; Qiao, Jun; Sloop, Steven E.; Tian, Minmin; Wang, Shanger

    1999-01-01

    Studies of polymer electrolyte solutions for lithium-polymer batteries are described. Two different salts, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium trifluoromethanesulfonate (LiTf), were dissolved in a variety of polymers. The structures were all based upon the ethylene oxide unit for lithium ion solvation and both linear and comb-branch polymer architectures have been examined. Conductivity, salt diffusion coefficient and transference number measurements demonstrate the superior transport properties of the LiTFSI salt over LiTf. Data obtained on all of these polymers combined with LiTFSI salts suggest that there is a limit to the conductivity achievable at room temperature, at least for hosts containing ethylene oxide units. The apparent conductivity limit is 5 x 10-5 S/cm at 25 C. Providing that the polymer chain segment containing the ethylene oxide units is at least 5-6 units long there appears to be little influence of the polymer framework to which the solvating groups are attached. To provide adequate separator function, the mechanical properties may be disconnected from the transport properties by selection of an appropriate architecture combined with an adequately long ethylene oxide chain. For both bulk and interfacial transport of the lithium ions, conductivity data alone is insufficient to understand the processes that occur. Lithium ion transference numbers and salt diffusion coefficients also play a major role in the observed behavior and the transport properties of these polymer electrolyte solutions appear to be quite inadequate for ambient temperature performance. At present, this restricts the use of such systems to high temperature applications. Several suggestions are given to overcome these obstacles

  14. Modification of steel surface by plasma electrolytic saturation with nitrogen and carbon

    Energy Technology Data Exchange (ETDEWEB)

    Kusmanov, S.A., E-mail: sakusmanov@yandex.ru; Kusmanova, Yu.V., E-mail: yulia.kusmanova@yandex.ru; Smirnov, A.A., E-mail: sciencealexsm@gmail.com; Belkin, P.N., E-mail: belkinp@yandex.ru

    2016-06-01

    The effect of the electrolyte composition with ammonia, acetone, and ammonium chloride on the structure and properties of low carbon steel was studied in anode plasma electrolytic nitrocarburising. An X-ray diffractometer, a scanning electron microscopy (SEM) and an optical microscope were used to characterize the phase composition of the modified layer and its surface morphology. Surface roughness was studied with a profilometer–profilograph. The hardness of the treated and untreated samples was measured using a microhardness tester. The sources of nitrogen and carbon are shown to be the products of evaporation and thermal decomposition of the electrolyte components. It is established that the influence of concentration of ammonia, acetone, and ammonium chloride on the size of the structural components of the hardened layer is explained by the competition of the anode dissolution, high-temperature oxidation and diffusion of the saturating component. The electrolyte composition (10–12.5% ammonium chloride, 5% acetone, 5% ammonia) and processing mode (800 °C, 5–10 min) of low carbon steels allowing to obtain the hardened surface layer up to 0.2 mm with microhardness 930 HV and with decrease in the roughness (R{sub a}) from 1.013 to 0.054 μm are proposed. The anode plasma electrolytic nitricarburising is able to decrease friction coefficient of the treated low carbon steel from 0.191 to 0.169 and wear rate from 13.5 mg to 1.0 mg. - Highlights: • Aqueous solution (12.5% NH{sub 4}Cl, 5% ammonia, 5% acetone) is proposed for PEN/C steels. • Microhardness of steel (0.2% C) is 930 HV due to PEN/C for 5–10 min at 800 °C. • Anode PEN/C of low carbon steel decreases its roughness (R{sub a}) from 1.013 to 0.054 μm. • Anode PEN/C decreases friction coefficient of low carbon steel from 0.191 to 0.169 • Anode PEN/C decreases wear loss of low carbon steel from 13.5 mg to 1.0 mg.

  15. Dual Electrolytic Plasma Processing for Steel Surface Cleaning and Passivation

    Science.gov (United States)

    Yang, L.; Zhang, P.; Shi, J.; Liang, J.; Tian, W. B.; Zhang, Y. M.; Sun, Z. M.

    2017-10-01

    To remove the rust on rebars and passivate the fresh surfaces, electrodes reversing electrolytic plasma processing (EPP) was proposed and conducted in a 10 wt.% Na2CO3 aqueous solution. The morphology and the composition of the surface were investigated by SEM and XPS. Experimental results show that the rust on the surface was removed effectively by cathode EPP, and a passive film containing Cr2O3 was achieved by the succeeding anode EPP treatment, by a simple operation of reversing the bias. The corrosion resistance was evaluated in a 3.5 wt.% NaCl aqueous solution using an electrochemical workstation. In comparison, the corrosion resistance was improved by the succeeding anode EPP treatment, which is evidenced by a positive shift of the open-circuit potential, an increase in the electrochemical impedance representing the inner layer by 76.8% and the decrease in the corrosion current density by 49.6%. This is an effective and environment-friendly technique to clean and passivate rebars and similar steel materials.

  16. Research of plasma-electrolyte discharge in the processes of obtaining metallic powders

    Science.gov (United States)

    Kashapov, R. N.; Kashapov, L. N.; Kashapov, N. F.

    2017-11-01

    The use of the plasma electrolyte process has never been considered as a simple, cheap and fast method of obtaining powders used in selective laser melting processes. Therefore, the adaptation of the plasma-electrolyte process to the production of metal powders used in additive production is an urgent task. The paper presents the results of studies of gas discharge parameters between a metal and liquid electrode in the processes of obtaining metallic iron powders. The discharge combustion conditions necessary for the formation of metal powders of micron size are determined. A possible mechanism for the formation of powder particles in a discharge plasma is proposed.

  17. Zirconium oxide based ceramic solid electrolytes for oxygen detection

    International Nuclear Information System (INIS)

    Caproni, Erica

    2007-01-01

    Taking advantage of the high thermal shock resistance of zirconia-magnesia ceramics and the high oxide ion conductivity of zirconia-yttria ceramics, composites of these ceramics were prepared by mixing, pressing and sintering different relative concentrations of ZrO 2 : 8.6 mol% MgO and ZrO 2 : 3 mol% Y 2 O 3 solid electrolytes. Microstructural analysis of the composites was carried out by X-ray diffraction and scanning electron microscopy analyses. The thermal behavior was studied by dilatometric analysis. The electrical behavior was evaluated by the impedance spectroscopy technique. An experimental setup was designed for measurement the electrical signal generated as a function of the amount of oxygen at high temperatures. The main results show that these composites are partially stabilized (monoclinic, cubic and tetragonal) and the thermal behavior is similar to that of ZrO 2 : 8.6 mol% MgO materials used in disposable high temperature oxygen sensors. Moreover, the results of analysis of impedance spectroscopy show that the electrical conductivity of zirconia:magnesia is improved with zirconia-yttria addition and that the electrical signal depends on the amount of oxygen at 1000 deg C, showing that the ceramic composites can be used in oxygen sensors. (author)

  18. Molybdenum oxide nanowires based supercapacitors with enhanced capacitance and energy density in ethylammonium nitrate electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Sarfraz, Mansoor; Aboud, Mohamed F.A.; Shakir, Imran, E-mail: shakir@skku.edu

    2015-11-25

    Orthorhombic molybdenum trioxide (α-MoO{sub 3}) nanowires as an electrode for electrochemical supercapacitors in ethylammonium nitrate (EAN) electrolyte exhibits a high specific capacitance of 288 Fg{sup −1}, which is 8 times higher than the specific capacitance obtained from MoO{sub 3} nanowires in water based electrolyte. MoO{sub 3} nanowires in EAN electrolyte exhibit energy density of 46.32 Wh kg{sup −1} at a power density of 20.3 kW kg{sup −1} with outstanding cycling stability with specific capacitance retention of 96% over 3000 cycles. We believe that the superior performance of the MoO{sub 3} nanowires in EAN based electrolyte is primarily due to its relatively low viscosity (0.28 P at 25 °C), high electrical conductivity (20 mS cm{sup −1} at 25 °C) and large working voltage window. The results clearly demonstrate that EAN as electrolyte is one of the most promising electrolyte for high performance large scale energy storage devices. - Highlights: • Synthesis of single crystalline molybdenum oxide nanowires. • Ethylammonium Nitrate as an electrolyte for high performance large scale psuedocapacitor based energy storage devices. • Molybdenum oxide nanowires based electrodes shows 8 fold enhancement in Ethylammonium Nitrate electrolyte as compared to water based electrolytes. • The devices in Ethylammonium Nitrate exhibit excellent stability, retaining 96% of its initial capacity after 3000 cycles.

  19. Sweating, thirst perception and plasma electrolyte composition in ...

    African Journals Online (AJOL)

    Thirst is a perception, the subjective experience evoked by fluid deficits. Exercise induces sweating and subsequently electrolyte loss and thirst but there is little documented on post exercise thirst perception in women of varying body mass indices. 40 apparently healthy young women (19-25years) in the follicular phase of ...

  20. Spectroscopic investigation of plasma electrolytic borocarburizing on q235 low-carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Run [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Zhenjiang Watercraft College, Zhenjiang 212000, Jiangsu (China); Wang, Bin; Wu, Jie [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Xue, Wenbin, E-mail: xuewb@bnu.edu.cn [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Jin, Xiaoyue; Du, Jiancheng; Hua, Ming [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

    2014-12-01

    Highlights: • The plasma discharge behaviors for PEB/C on steels were evaluated by OES. • Electron temperature, concentration, atomic ionization degree were calculated. • The decomposition mechanism of electrolyte and was analyzed. - Abstract: A plasma electrolytic borocarburizing process (PEB/C) in borax electrolyte with glycerin additive was employed to fabricate a hardening layer on Q235 low-carbon steel. Optical emission spectroscopy (OES) was utilized to investigate the spectroscopy characteristics of plasma discharge around the steel during PEB/C process. Some plasma parameters were calculated in terms of OES. The electron temperature and electron concentration in plasma discharge zone is about 3000–12,000 K and 2 × 10{sup 22} m{sup −3}–1.4 × 10{sup 23} m{sup −3}. The atomic ionization degrees of iron, carbon and boron are 10{sup −16}–10{sup −3}, and 10{sup −23}–10{sup −6}, 10{sup −19}–10{sup −4}, respectively, which depend on discharge time. The surface morphology and cross-sectional microstructure of PEB/C hardening layer were observed, and the electrolyte decomposition and plasma discharge behaviors were discussed.

  1. Spectroscopic investigation of plasma electrolytic borocarburizing on q235 low-carbon steel

    International Nuclear Information System (INIS)

    Liu, Run; Wang, Bin; Wu, Jie; Xue, Wenbin; Jin, Xiaoyue; Du, Jiancheng; Hua, Ming

    2014-01-01

    Highlights: • The plasma discharge behaviors for PEB/C on steels were evaluated by OES. • Electron temperature, concentration, atomic ionization degree were calculated. • The decomposition mechanism of electrolyte and was analyzed. - Abstract: A plasma electrolytic borocarburizing process (PEB/C) in borax electrolyte with glycerin additive was employed to fabricate a hardening layer on Q235 low-carbon steel. Optical emission spectroscopy (OES) was utilized to investigate the spectroscopy characteristics of plasma discharge around the steel during PEB/C process. Some plasma parameters were calculated in terms of OES. The electron temperature and electron concentration in plasma discharge zone is about 3000–12,000 K and 2 × 10 22 m −3 –1.4 × 10 23 m −3 . The atomic ionization degrees of iron, carbon and boron are 10 −16 –10 −3 , and 10 −23 –10 −6 , 10 −19 –10 −4 , respectively, which depend on discharge time. The surface morphology and cross-sectional microstructure of PEB/C hardening layer were observed, and the electrolyte decomposition and plasma discharge behaviors were discussed

  2. Electrolytic exfoliation of graphite in water with multifunctional electrolytes: en route towards high quality, oxide-free graphene flakes.

    Science.gov (United States)

    Munuera, J M; Paredes, J I; Villar-Rodil, S; Ayán-Varela, M; Martínez-Alonso, A; Tascón, J M D

    2016-02-07

    Electrolytic--usually referred to as electrochemical--exfoliation of graphite in water under anodic potential holds enormous promise as a simple, green and high-yield method for the mass production of graphene, but currently suffers from several drawbacks that hinder its widespread adoption, one of the most critical being the oxidation and subsequent structural degradation of the carbon lattice that is usually associated with such a production process. To overcome this and other limitations, we introduce and implement the concept of multifunctional electrolytes. The latter are amphiphilic anions (mostly polyaromatic hydrocarbons appended with sulfonate groups) that play different relevant roles as (1) an intercalating electrolyte to trigger exfoliation of graphite into graphene flakes, (2) a dispersant to afford stable aqueous colloidal suspensions of the flakes suitable for further use, (3) a sacrificial agent to prevent graphene oxidation during exfoliation and (4) a linker to promote nanoparticle anchoring on the graphene flakes, yielding functional hybrids. The implementation of this strategy with some selected amphiphiles even furnishes anodically exfoliated graphenes of a quality similar to that of flakes produced by direct, ultrasound- or shear-induced exfoliation of graphite in the liquid phase (i.e., almost oxide- and defect-free). These high quality materials were used for the preparation of catalytically efficient graphene-Pt nanoparticle hybrids, as demonstrated by model reactions (reduction of nitroarenes). The multifunctional performance of these electrolytes is also discussed and rationalized, and a mechanistic picture of their oxidation-preventing ability is proposed. Overall, the present results open the prospect of anodic exfoliation as a competitive method for the production of very high quality graphene flakes.

  3. Crystalline structure and microstructural characteristics of the cathode/electrolyte solid oxide half-cells

    International Nuclear Information System (INIS)

    Chiba, Rubens; Vargas, Reinaldo Azevedo; Andreoli, Marco; Santoro, Thais Aranha de Barros; Seo, Emilia Satoshi Miyamaru

    2009-01-01

    The solid oxide fuel cell (SOFC) is an electrochemical device generating of electric energy, constituted of cathode, electrolyte and anode; that together they form a unity cell. The study of the solid oxide half-cells consisting of cathode and electrolyte it is very important, in way that is the responsible interface for the reduction reaction of the oxygen. These half-cells are ceramic materials constituted of strontium-doped lanthanum manganite (LSM) for the cathode and yttria-stabilized zirconia (YSZ) for the electrolyte. In this work, two solid oxide half-cells have been manufactured, one constituted of LSM cathode thin film on YSZ electrolyte substrate (LSM - YSZ half-cell), and another constituted of LSM cathode and LSM/YSZ composite cathode thin films on YSZ electrolyte substrate (LSM - LSM/YSZ - YSZ half cell). The cathode/electrolyte solid oxide half-cells were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results have been presented with good adherence between cathode and electrolyte and, LSM and YSZ phases were identified. (author)

  4. Application of atmospheric-pressure plasma jet processed carbon nanotubes to liquid and quasi-solid-state gel electrolyte supercapacitors

    Science.gov (United States)

    Kuok, Fei-Hong; Kan, Ken-Yuan; Yu, Ing-Song; Chen, Chieh-Wen; Hsu, Cheng-Che; Cheng, I.-Chun; Chen, Jian-Zhang

    2017-12-01

    We use a dc-pulse nitrogen atmospheric-pressure plasma jet (APPJ) to calcine carbon nanotubes (CNTs) pastes that are screen-printed on carbon cloth. 30-s APPJ treatment can efficiently oxidize and vaporize the organic binders, thereby forming porous structures. As indicated by X-ray photoelectron spectroscopy (XPS) and electron probe microanalysis (EPMA), the oxygen content decreases after APPJ treatment owing to the oxidation and vaporization of ethyl cellulose, terpineol, and ethanol. Nitrogen doping was introduced to the materials by the nitrogen APPJ. APPJ-calcination improves the wettability of the CNTs printed on carbon cloth, as evidenced by water contact angle measurement. Raman spectroscopy indicates that reactive species of nitrogen APPJ react violently with CNTs in only 30-s APPJ processing time and introduce defects and/or surface functional groups on CNTs. Carbon cloths with calcined CNT layers are used as electrodes for liquid and quasi-solid-state electrolyte supercapacitors. Under a cyclic voltammetry test with a 2 mV/s potential scan rate, the specific capacitance is 73.84 F/g (areal capacitance = 5.89 mF/cm2) with a 2 M KCl electrolyte and 66.47 F/g (areal capacitance = 6.10 mF/cm2) with a H2SO4/polyvinyl alcohol (PVA) gel electrolyte.

  5. Multi-layer thin-film electrolytes for metal supported solid oxide fuel cells

    Science.gov (United States)

    Haydn, Markus; Ortner, Kai; Franco, Thomas; Uhlenbruck, Sven; Menzler, Norbert H.; Stöver, Detlev; Bräuer, Günter; Venskutonis, Andreas; Sigl, Lorenz S.; Buchkremer, Hans-Peter; Vaßen, Robert

    2014-06-01

    A key to the development of metal-supported solid oxide fuel cells (MSCs) is the manufacturing of gas-tight thin-film electrolytes, which separate the cathode from the anode. This paper focuses the electrolyte manufacturing on the basis of 8YSZ (8 mol.-% Y2O3 stabilized ZrO2). The electrolyte layers are applied by a physical vapor deposition (PVD) gas flow sputtering (GFS) process. The gas-tightness of the electrolyte is significantly improved when sequential oxidic and metallic thin-film multi-layers are deposited, which interrupt the columnar grain structure of single-layer electrolytes. Such electrolytes with two or eight oxide/metal layers and a total thickness of about 4 μm obtain leakage rates of less than 3 × 10-4 hPa dm3 s-1 cm-2 (Δp: 100 hPa) at room temperature and therefore fulfill the gas tightness requirements. They are also highly tolerant with respect to surface flaws and particulate impurities which can be present on the graded anode underground. MSC cell tests with double-layer and multilayer electrolytes feature high power densities more than 1.4 W cm-2 at 850 °C and underline the high potential of MSC cells.

  6. Plasma electrolytes in patients with asthma in a tertiary hospital in ...

    African Journals Online (AJOL)

    Background: We compared plasma electrolytes in patients with and without asthma. Methods: Subjects for the study comprised of 17 male and 45 female asthmatics attending the Chest Clinic of the University of Benin Teaching Hospital (UBTH), Benin City, Nigeria. These patients had questionnaires administered and the ...

  7. Surface modification by electrolytic plasma processing for high Nb-TiAl alloys

    Science.gov (United States)

    Gui, Wanyuan; Hao, Guojian; Liang, Yongfeng; Li, Feng; Liu, Xiao; Lin, Junpin

    2016-12-01

    Metal surface modification by electrolytic plasma processing (EPP) is an innovative treatment widely commonly applied to material processing and pretreatment process of coating and galvanization. EPP involves complex processes and a great deal of parameters, such as preset voltage, current, solution temperature and processing time. Several characterization methods are presented in this paper for evaluating the micro-structure surfaces of Ti45Al8Nb alloys: SEM, EDS, XRD and 3D topography. The results showed that the oxide scale and other contaminants on the surface of Ti45Al8Nb alloys can be effectively removed via EPP. The typical micro-crater structure of the surface of Ti45Al8Nb alloys were observed by 3D topography after EPP to find that the mean diameter of the surface structure and roughness value can be effectively controlled by altering the processing parameters. The mechanical properties of the surface according to nanomechanical probe testing exhibited slight decrease in microhardness and elastic modulus after EPP, but a dramatic increase in surface roughness, which is beneficial for further processing or coating.

  8. Performance of a novel type of electrolyte-supported solid oxide fuel cell with honeycomb structure

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-Morales, Juan Carlos; Savvin, Stanislav N.; Nunez, Pedro [Departmento de Quimica Inorganica, Universidad de La Laguna, 38200 Tenerife (Spain); Marrero-Lopez, David [Departamento de Fisica Aplicada I, Universidad de Malaga, 29071 Malaga (Spain); Pena-Martinez, Juan; Canales-Vazquez, Jesus [Instituto de Energias Renovables-Universidad de Castilla la Mancha, 02006 Albacete (Spain); Roa, Joan Josep; Segarra, Merce [DIOPMA, Departamento de Ciencia de los Materiales e Ing. Metalurgica, 08028 Barcelona (Spain)

    2010-01-15

    A novel design, alternative to the conventional electrolyte-supported solid oxide fuel cell (SOFC) is presented. In this new design, a honeycomb-electrolyte is fabricated from hexagonal cells, providing high mechanical strength to the whole structure and supporting the thin layer used as electrolyte of a SOFC. This new design allows a reduction of {proportional_to}70% of the electrolyte material and it renders modest performances over 320 mW cm{sup -2} but high volumetric power densities, i.e. 1.22 W cm{sup -3} under pure CH{sub 4} at 900 C, with a high OCV of 1.13 V, using the standard Ni-YSZ cermet as anode, Pt as cathode material and air as the oxidant gas. (author)

  9. Electrochemical oxidation of organic carbonate based electrolyte solutions at lithium metal oxide electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Imhof, R; Novak, P [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    The oxidative decomposition of carbonate based electrolyte solutions at practical lithium metal oxide composite electrodes was studied by differential electrochemical mass spectrometry. For propylene carbonate (PC), CO{sub 2} evolution was detected at LiNiO{sub 2}, LiCoO{sub 2}, and LiMn{sub 2}O{sub 4} composite electrodes. The starting point of gas evolution was 4.2 V vs. Li/Li{sup +} at LiNiO{sub 2}, whereas at LiCoO{sub 2} and LiMn{sub 2}O{sub 4}, CO{sub 2} evolution was only observed above 4.8 V vs. Li/Li{sup +}. In addition, various other volatile electrolyte decomposition products of PC were detected when using LiCoO{sub 2}, LiMn{sub 2}O4, and carbon black electrodes. In ethylene carbonate / dimethyl carbonate, CO{sub 2} evolution was only detected at LiNiO{sub 2} electrodes, again starting at about 4.2 V vs. Li/Li{sup +}. (author) 3 figs., 2 refs.

  10. Cathode and electrolyte materials for solid oxide fuel cells and ion transport membranes

    Science.gov (United States)

    Jacobson, Allan J; Wang, Shuangyan; Kim, Gun Tae

    2014-01-28

    Novel cathode, electrolyte and oxygen separation materials are disclosed that operate at intermediate temperatures for use in solid oxide fuel cells and ion transport membranes based on oxides with perovskite related structures and an ordered arrangement of A site cations. The materials have significantly faster oxygen kinetics than in corresponding disordered perovskites.

  11. On the theory of the electroreduction of solid oxide electrolytes

    International Nuclear Information System (INIS)

    Chebotin, V.N.; Brajnin, M.I.; Solov'eva, L.M.; Pakhnutov, I.A.; Lukach, Yu.S.

    1986-01-01

    The process of direct current passage through the cell with MOsub(2)+MeOsub(r) solid electrolyte (M-Zr, Hf, Ce, Th; Me-Ca, Sr, Sc, Y, lanthanides), a blockage cathode and a reversible anode is considered; it leads to electrolyte deviation from stoichiometric composition to insufficient oxygen content. The degree of this deviation and n-type electron conductivity proportional to it, depending on coordinate and time, is described by the nonlinear differential equation of the diffusion type. Electron conductivity of the electrolyte near the cathode increases in time approximating to the limiting value proportional to current conducted. As the distance to the cathode increases electron conductivity reduces by the exponential law, which transforms to a linear one in due course

  12. Degradation of the corrosion resistance of anodic oxide films through immersion in the anodising electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Rubio, M. [Departamento de Quimica-Fisica Aplicada, Universidad Autonoma de Madrid, 28049-Madrid (Spain); Department of Surface Technologies, Engineering of Materials and Processes, Airbus Spain, Av. John Lennon s/n 28906-Getafe (Spain); Ocon, P., E-mail: pilar.ocon@uam.e [Departamento de Quimica-Fisica Aplicada, Universidad Autonoma de Madrid, 28049-Madrid (Spain); Curioni, M.; Thompson, G.E.; Skeldon, P. [Corrosion and Protection Center, School of Materials, The University of Manchester, M60 1QD England (United Kingdom); Lavia, A. [Department of Surface Technologies, Engineering of Materials and Processes, Airbus Spain, Av. John Lennon s/n 28906-Getafe (Spain); Garcia, I. [Department of Surface Technologies, Engineering of Materials and Processes, Airbus Spain, Av. John Lennon s/n 28906-Getafe (Spain); Department of Corrosion and Protection, National Center for Metallurgical Research CENIM-CSIC, Av. Gregorio del Amo 8, 28040-Madrid (Spain)

    2010-07-15

    The deterioration of AA2024, AA6061 and AA7475 anodised in an environmentally-compliant tartaric acid/sulphuric acid electrolyte has been examined as a function of the immersion time in the electrolyte after termination of anodising. By transmission electron microscopy and scanning electron microscopy, degradation of the porous oxide film was qualitatively observed on AA2024. Electrochemical impedance spectroscopy revealed that AA2024 and AA7075 were more sensitive to prolonged immersion in the anodising electrolyte compared with AA6061, due to increased barrier layer thinning rates and increased susceptibility to localized corrosion. Salt spray tests confirmed the previous, indicating decay of anticorrosion performance for AA2024 and AA7075.

  13. Degradation of the corrosion resistance of anodic oxide films through immersion in the anodising electrolyte

    International Nuclear Information System (INIS)

    Garcia-Rubio, M.; Ocon, P.; Curioni, M.; Thompson, G.E.; Skeldon, P.; Lavia, A.; Garcia, I.

    2010-01-01

    The deterioration of AA2024, AA6061 and AA7475 anodised in an environmentally-compliant tartaric acid/sulphuric acid electrolyte has been examined as a function of the immersion time in the electrolyte after termination of anodising. By transmission electron microscopy and scanning electron microscopy, degradation of the porous oxide film was qualitatively observed on AA2024. Electrochemical impedance spectroscopy revealed that AA2024 and AA7075 were more sensitive to prolonged immersion in the anodising electrolyte compared with AA6061, due to increased barrier layer thinning rates and increased susceptibility to localized corrosion. Salt spray tests confirmed the previous, indicating decay of anticorrosion performance for AA2024 and AA7075.

  14. Fermi Potential across Working Solid Oxide Cells with Zirconia or Ceria Electrolytes

    DEFF Research Database (Denmark)

    Jacobsen, Torben; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2014-01-01

    A solid electrolyte will always possess a finite electronic conductivity, in particular electrolytes like doped ceria that easily get reduced and become mixed ionic and electronic conductors. This given rise too high leak currents through the solid oxide cell (SOC). Especially, problems have been...... driving the O2-ions is not the Fermi potential, which is the potential of the electrons, but the Galvani potential (or inner potential) (1). The concepts of potentials describing the electrical situation of a solid electrolyte is shown i Fig. 1, and an example of the Fermi potential (π) and Galvani...

  15. Transition of hydrated oxide layer for aluminum electrolytic capacitors

    International Nuclear Information System (INIS)

    Chi, Choong-Soo; Jeong, Yongsoo; Ahn, Hong-Joo; Lee, Jong-Ho; Kim, Jung-Gu; Lee, Jun-Hee; Jang, Kyung-Wook; Oh, Han-Jun

    2007-01-01

    A hydrous oxide film for the application as dielectric film is synthesized by immersion of pure aluminum in hot water. From a Rutherford backscattering analysis, the ratio of aluminum to oxygen atoms was found to be 3:2 in the anodized aluminum oxide film, and 2:1 in the hydrous oxide layer. Anodization of the hydrous oxide layer was more effective for the transition of amorphous anodic oxides to the crystalline aluminum oxides

  16. Evaluation of Plasma Electrolytes in Patients Suffering From ...

    African Journals Online (AJOL)

    Anthropometric indices of all subjects were also determined. The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria and Hamilton Depression Rating Scale were used for diagnosis and measurement of severity of depression respectively. The mean plasma sodium (p<0.05) and potassium (p<0.01) were ...

  17. Structure and conductive properties of poly(ethylene oxide)/layered double hydroxide nanocomposite polymer electrolytes

    International Nuclear Information System (INIS)

    Liao, C.-S.; Ye, W.-B.

    2004-01-01

    The oligo(ethylene oxide) modified layered double hydroxide (LDH) prepared by template method was added as a nanoscale nucleating agent into poly(ethylene oxide) (PEO) to form PEO/OLDH nanocomposite electrolytes. The effects of OLDH addition on morphology and conductivities of nanocomposite electrolytes were studied using wide-angle X-ray diffractometer, polarized optical microscopy, differential scanning calorimetry and ionic conductivity measurement. The results show that the exfoliated morphology of nanocomposites is formed due to the surface modification of LDH layers with PEO matrix compatible oligo(ethylene oxide)s. The nanoscale dispersed OLDH layers inhibit the crystal growth of PEO crystallites and result in a plenty amount of intercrystalline grain boundary within PEO/OLDH nanocomposites. The ionic conductivities of nanocomposite electrolytes are enhanced by three orders of magnitude compared to the pure PEO polymer electrolytes at ambient temperature. It can be attributed to the ease transport of Li + along intercrystalline amorphous phase. This novel nanocomposite electrolytes system with high conductivities will be benefited to fabricate the thin-film type of Li-polymer secondary battery

  18. Borate electrolyte additives for high voltage lithium nickel manganese oxide electrode: A comparative study

    International Nuclear Information System (INIS)

    Chen, Zhiting; Wang, Cun; Xing, Lidan; Wang, Xianshu; Tu, Wenqiang; Zhu, Yunmin; Li, Weishan

    2017-01-01

    Highlights: •TMB and TEB effective improve the cyclic stability of LNMO at high voltage. •The performance of LNMO with TMB-containing electrolyte is superior to that of TEB. •LNMO shows catalytic effect on the oxidation reaction of TEB. •The film generated in TMB shows better ability on suppressing LNMO shedding than TEB. -- Abstract: Trimethyl borate (TMB) and triethyl borate (TEB) are used as film-forming electrolyte additives for high voltage Lithium nickel manganese oxide (LNMO) cathode. DFT calculation and initial charge curve of LNMO reveal that the oxidation activity of TEB is higher than that of TMB. Addition of 2% TMB and 2% TEB effectively improve the capacity retention of high voltage LNMO from 23.4% to 85.3% and 72.6% after 600 cycles, respectively. The film generated in TMB-containing electrolyte shows better ability on suppressing the LNMO shedding in comparison with that of TEB, resulting in higher capacity retention of LNMO in TMB-containing electrolyte at high voltage. The superior performance of LNMO with TMB-containing electrolyte should be ascribed to its less intense film-forming reaction which generates a denser protective surface film on LNMO surface. However, why LNMO shows catalyzation effect on TEB oxidation but not on TMB is unclear, which needs further intensive investigation.

  19. Oxide cathodes produced by plasma deposition

    International Nuclear Information System (INIS)

    Scheitrum, G.; Caryotakis, G.; Pi, T.; Umstattd, R.; Brown, I.; Montiero, O.

    1997-01-01

    These are two distinct applications for high-current-density, long-life thermionic cathodes. The first application is as a substitute for explosive emission cathodes used in high-power microwave (HPM) devices being developed for Air Force programs. The second application is in SLAC's X-band klystrons for the Next Linear Collider (NLC). SLAC, UCD, and LBL are developing a plasma deposition process that eliminates the problems with binders, carbonate reduction, peeling, and porosity. The emission layer is deposited using plasma deposition of metallic barium in vacuum with an oxygen background gas. An applied bias voltage drives the oxide plasma into the nickel surface. Since the oxide is deposited directly, it does not have problems with poisoning from a hydrocarbon binder. The density of the oxide layer is increased from the 40--50% for standard oxide cathodes to nearly 100% for plasma deposition

  20. Effect of electrolyte temperature on the formation of self-organized anodic niobium oxide microcones in hot phosphate-glycerol electrolyte

    Science.gov (United States)

    Yang, S.; Aoki, Y.; Habazaki, H.

    2011-07-01

    Nanoporous niobium oxide films with microcone-type surface morphology were formed by anodizing at 10 V in glycerol electrolyte containing 0.6 mol dm -3 K 2HPO 4 and 0.2 mol dm -3 K 3PO 4 in a temperature range of 428-453 K. The microcones appeared after prolonged anodizing, but the required time was largely reduced by increasing electrolyte temperature. The anodic oxide was initially amorphous at all temperatures, but crystalline oxide nucleated during anodizing. The anodic oxide microcones, which were crystalline, appeared on surface as a consequence of preferential chemical dissolution of initially formed amorphous oxide. The chemical dissolution of an initially formed amorphous layer was accelerated by increasing the electrolyte temperature, with negligible influence of the temperature on the morphology of microcones up to 448 K.

  1. Effect of electrolyte temperature on the formation of self-organized anodic niobium oxide microcones in hot phosphate-glycerol electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Yang, S.; Aoki, Y. [Division of Materials Chemistry, Faculty of Engineering, Hokkaido University, Sapporo 060-8628 (Japan); Habazaki, H., E-mail: habazaki@eng.hokudai.ac.jp [Division of Materials Chemistry, Faculty of Engineering, Hokkaido University, Sapporo 060-8628 (Japan)

    2011-07-15

    Nanoporous niobium oxide films with microcone-type surface morphology were formed by anodizing at 10 V in glycerol electrolyte containing 0.6 mol dm{sup -3} K{sub 2}HPO{sub 4} and 0.2 mol dm{sup -3} K{sub 3}PO{sub 4} in a temperature range of 428-453 K. The microcones appeared after prolonged anodizing, but the required time was largely reduced by increasing electrolyte temperature. The anodic oxide was initially amorphous at all temperatures, but crystalline oxide nucleated during anodizing. The anodic oxide microcones, which were crystalline, appeared on surface as a consequence of preferential chemical dissolution of initially formed amorphous oxide. The chemical dissolution of an initially formed amorphous layer was accelerated by increasing the electrolyte temperature, with negligible influence of the temperature on the morphology of microcones up to 448 K.

  2. Cycling of lithium/metal oxide cells using composite electrolytes containing fumed silicas

    International Nuclear Information System (INIS)

    Zhou Jian; Fedkiw, Peter S.

    2003-01-01

    The effect on cycle capacity is reported of cathode material (metal oxide, carbon, and current collector) in lithium/metal oxide cells cycled with fumed silica-based composite electrolytes. Three types of electrolytes are compared: filler-free electrolyte consisting of methyl-terminated poly(ethylene glycol) oligomer (PEGdm, M w =250)+lithium bis(trifluromethylsufonyl)imide (LiTFSI) (Li:O=1:20), and two composite systems of the above baseline liquid electrolyte containing 10-wt% A200 (hydrophilic fumed silica) or R805 (hydrophobic fumed silica with octyl surface group). The composite electrolytes are solid-like gels. Three cathode active materials (LiCoO 2 , V 6 O 13 , and Li x MnO 2 ), four conducting carbons (graphite Timrex [reg] SFG 15, SFG 44, carbon black Vulcan XC72R, and Ketjenblack EC-600JD), and three current collector materials (Al, Ni, and carbon fiber) were studied. Cells with composite electrolytes show higher capacity, reduced capacity fade, and less cell polarization than those with filler-free electrolyte. Among the three active materials studied, V 6 O 13 cathodes deliver the highest capacity and Li x MnO 2 cathodes render the best capacity retention. Discharge capacity of Li/LiCoO 2 cells is affected greatly by cathode carbon type, and the capacity decreases in the order of Ketjenblack>SFG 15>SFG 44>Vulcan. Current collector material also plays a significant role in cell cycling performance. Lithium/vanadium oxide (V 6 O 13 ) cells deliver increased capacity using Ni foil and carbon fiber current collectors in comparison to an Al foil current collector

  3. Microwave assisted sintering of gadolinium doped barium cerate electrolyte for intermediate temperature solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Arumugam Senthil, E-mail: senthu.ramp@gmail.com [Department of Physics, PSG College of Technology, Coimbatore, 641 004, Tamilnadu (India); Balaji, Ramamoorthy [Department of Physics, PSG College of Technology, Coimbatore, 641 004, Tamilnadu (India); Jayakumar, Srinivasalu [Department of Physics, PSG Institute of Technology and Applied Research, Coimbatore, 641 062, Tamilnadu (India); Pradeep, Chandran [Department of Physics, Indian Institute of Technology, Madras, 600 036, Tamilnadu (India)

    2016-10-01

    In Solid Oxide Fuel Cell (SOFC), electrolyte plays a vital role to increase the energy conversion efficiency. The main hurdle of such electrolyte in fuel cell is its higher operating temperature (1000 °C) which results in design limitation and higher fabrication cost. In order to reduce the operating temperature of SOFC, a suitable electrolyte has been prepared through co-precipitation method followed by microwave sintering of solid ceramic. The calcination temperature for the as-prepared powder was identified using Differential Scanning Calorimetry. The crystal structure of the sample was found to exhibit its orthorhombic perovskite structure. The particle size was determined using High-Resolution Transmission Electron Microscope with uniform in shape and size, match with XRD results and confirmed from structural analysis. Thus, the sample prepared via co-precipitation method and the solid ceramic sintered through microwave can be a promising electrolyte for fuel cells operated at intermediate temperature. - Highlights: • To synthesis the composite electrolyte by chemical method and sinter using microwave. • To reduce the operating temperature of electrolyte for high ionic conductivity in SOFC's. • To study the phase purity and to develop nanocomposite at reduced temperature.

  4. Faster dissolution of PuO2 in nitrous media by means of electrolytic oxidation

    International Nuclear Information System (INIS)

    Baumgaertner, F.; Kim, J.I.; Luckner, N.; Brueckl, N.; Lieberer, E.

    1984-03-01

    The contribution shows that the dissolution of PuO 2 in HNO 3 can be accelerated considerably by means of electrolytic oxidation. A glass apparatus has been developed which uses platinum electrodes providing for sufficient contact between electrodes and solids. Increase of temperature, acid concentration, and electrode current density, and a good contact between electrode and metal oxide will improve the dissolution kinetics. The reaction could be made even faster by addition of Ce 4+ . (orig.) [de

  5. Electrolytes for methanol-air fuel cells. I. The performance of methanol electro-oxidation catalysts in sulphuric acid and phosphoric acid electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Andrew, M.R.; McNicol, B.D.; Short, R.T.; Drury, J.S.

    1977-03-01

    Phosphoric acid and sulphuric acid have been compared as potential electrolytes for methanol-air fuel cells. The performances of typical electro-oxidation catalysts were measured in both electrolytes over a range of concentrations. With all catalysts the activity falls with increasing acid concentration. While this is to some extent due to the decrease in water activity at higher concentrations it seems that with both acids there is significant poisoning of the catalyst. The results can be explained for both electrolytes by assuming that adsorption of undissociated acid poisons the catalyst surfaces and that the reaction rate on the poisoned surfaces is proportional to the water activity.

  6. A plasma needle generates nitric oxide

    International Nuclear Information System (INIS)

    Stoffels, E; Gonzalvo, Y Aranda; Whitmore, T D; Seymour, D L; Rees, J A

    2006-01-01

    Generation of nitric oxide (NO) by a plasma needle is studied by means of mass spectrometry. The plasma needle is an atmospheric glow generated by a radio-frequency excitation in a mixture of helium and air. This source is used for the treatment of living tissues, and nitric oxide may be one of the most important active agents in plasma therapy. Efficient NO generation is of particular importance in the treatment of cardiovascular diseases. Mass spectrometric measurements have been performed under various plasma conditions; gas composition in the plasma and conversion of feed gases (nitrogen and oxygen) into other species has been studied. Up to 30% of the N 2 and O 2 input is consumed in the discharge, and NO has been identified as the main conversion product

  7. Solvothermal synthesis of gallium-indium-zinc-oxide nanoparticles for electrolyte-gated transistors.

    Science.gov (United States)

    Santos, Lídia; Nunes, Daniela; Calmeiro, Tomás; Branquinho, Rita; Salgueiro, Daniela; Barquinha, Pedro; Pereira, Luís; Martins, Rodrigo; Fortunato, Elvira

    2015-01-14

    Solution-processed field-effect transistors are strategic building blocks when considering low-cost sustainable flexible electronics. Nevertheless, some challenges (e.g., processing temperature, reliability, reproducibility in large areas, and cost effectiveness) are requirements that must be surpassed in order to achieve high-performance transistors. The present work reports electrolyte-gated transistors using as channel layer gallium-indium-zinc-oxide nanoparticles produced by solvothermal synthesis combined with a solid-state electrolyte based on aqueous dispersions of vinyl acetate stabilized with cellulose derivatives, acrylic acid ester in styrene and lithium perchlorate. The devices fabricated using this approach display a ION/IOFF up to 1 × 10(6), threshold voltage (VTh) of 0.3-1.9 V, and mobility up to 1 cm(2)/(V s), as a function of gallium-indium-zinc-oxide ink formulation and two different annealing temperatures. These results validates the usage of electrolyte-gated transistors as a viable and promising alternative for nanoparticle based semiconductor devices as the electrolyte improves the interface and promotes a more efficient step coverage of the channel layer, reducing the operating voltage when compared with conventional dielectrics gating. Moreover, it is shown that by controlling the applied gate potential, the operation mechanism of the electrolyte-gated transistors can be modified from electric double layer to electrochemical doping.

  8. Behavior of strontium- and magnesium-doped gallate electrolyte in direct carbon solid oxide fuel cells

    International Nuclear Information System (INIS)

    Zhang, Li; Xiao, Jie; Xie, Yongmin; Tang, Yubao; Liu, Jiang; Liu, Meilin

    2014-01-01

    Highlights: • La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3−δ (LSGM) can be used as electrolyte of direct carbon SOFCs. • DC-SOFC with LSGM electrolyte gives higher performance than that with YSZ. • LSGM-electrolyte DC-SOFC gives maximum power density of 383 mW cm −2 at 850 °C. • Operation of LSGM-DC-SOFC at 210 mA cm −2 lasts 72 min, with fuel utilization of 60%. - Abstract: Perovskite-type La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3−δ (LSGM) is synthesized by conventional solid state reaction. Its phase composition, microstructure, relative density, and oxygen-ionic conductivity are investigated. Tubular electrolyte-supported solid oxide fuel cells (SOFCs) are prepared with the LSGM as electrolyte and gadolinia doped ceria (GDC) mixed with silver as anode. The SOFCs are operated with Fe-loaded activated carbon as fuel and ambient air as oxidant. A typical single cell gives a maximum power density of 383 mW cm −2 at 850 °C, which is nearly 1.3 times higher than that of the similar cell with YSZ as electrolyte. A stability test of 72 min is carried out at a constant current density of 210 mA cm −2 , with a fuel utilization of 60%, indicating that LaGaO 3 -based electrolyte is promising to be applied in direct carbon SOFCs (DC-SOFCs)

  9. Behavior of strontium- and magnesium-doped gallate electrolyte in direct carbon solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Li; Xiao, Jie; Xie, Yongmin [The Key Laboratory of Fuel Cell Technology of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641 (China); Tang, Yubao [Key Laboratory of Sensor Analysis of Tumor Marker Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao o 266042 (China); Liu, Jiang, E-mail: jiangliu@scut.edu.cn [The Key Laboratory of Fuel Cell Technology of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641 (China); New Energy Research Institute, College of Environment and Energy, South China University of Technology, Guangzhou 510006 (China); Liu, Meilin [New Energy Research Institute, College of Environment and Energy, South China University of Technology, Guangzhou 510006 (China); School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, GA 30332-0245 (United States)

    2014-09-01

    Highlights: • La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 3−δ} (LSGM) can be used as electrolyte of direct carbon SOFCs. • DC-SOFC with LSGM electrolyte gives higher performance than that with YSZ. • LSGM-electrolyte DC-SOFC gives maximum power density of 383 mW cm{sup −2} at 850 °C. • Operation of LSGM-DC-SOFC at 210 mA cm{sup −2} lasts 72 min, with fuel utilization of 60%. - Abstract: Perovskite-type La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 3−δ} (LSGM) is synthesized by conventional solid state reaction. Its phase composition, microstructure, relative density, and oxygen-ionic conductivity are investigated. Tubular electrolyte-supported solid oxide fuel cells (SOFCs) are prepared with the LSGM as electrolyte and gadolinia doped ceria (GDC) mixed with silver as anode. The SOFCs are operated with Fe-loaded activated carbon as fuel and ambient air as oxidant. A typical single cell gives a maximum power density of 383 mW cm{sup −2} at 850 °C, which is nearly 1.3 times higher than that of the similar cell with YSZ as electrolyte. A stability test of 72 min is carried out at a constant current density of 210 mA cm{sup −2}, with a fuel utilization of 60%, indicating that LaGaO{sub 3}-based electrolyte is promising to be applied in direct carbon SOFCs (DC-SOFCs)

  10. Electrical and mechanical properties of poly(ethylene oxide)/intercalated clay polymer electrolyte

    International Nuclear Information System (INIS)

    Moreno, Mabel; Quijada, Raúl; Santa Ana, María A.; Benavente, Eglantina; Gomez-Romero, Pedro; González, Guillermo

    2011-01-01

    Highlights: ► Poly(ethylene oxide)/intercalated clay nanocomposite as filler in solid poly(ethylene oxide) electrolytes. ► Nanocomposite filler improves mechanical properties, transparency, and conductivity of poly(ethylene oxide) electrolyte films. ► Nanocomposite is more effective than unmodified clay in improving polymer electrolyte properties. ► Low Li/polymer ratio avoids crystalline Li complexes, so effects mainly arise from the polymer. ► High nanocomposite/poly(ethylene oxide)-matrix affinity enhances microhomogeneity in the polyelectrolyte. - Abstract: Solvent-free solid polymer electrolytes (SPEs) based on two different poly(ethylene oxide), PEO Mw 600,000 and 4,000,000 and intercalated clays are reported. The inorganic additives used were lithiated bentonite and the nanocomposite PEO-bentonite with the same polymer used as matrix. SPE films, obtained in the scale of grams by mixing the components in a Brabender-type batch mixer and molding at 130 °C, were characterized by X-ray diffraction analysis, UV–vis spectroscopy, and thermal analysis. During the preparation of the films, the unmodified clay got intercalated in situ. Comparative analysis of ionic conductivity and mechanical properties of the films show that the conductivity increases with the inclusion of fillers, especially for the polymer with low molecular weight. This effect is more pronounced when using PEO-bentonite as additive. Under selected work conditions, avoiding the presence of crystalline lithium complexes, observed effects are mainly centered on the polymer. An explanation, considering the higher affinity between the modified clay and PEO matrix which leads to differences in the micro homogeneity degree between both types of polymer electrolytes is proposed.

  11. Plasma Post Oxidation of Plasma Nitrocarburized SKD 61 Steel

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Plasma nitrocarburizing and plasma oxidizing treatments were performed to improve the wear and corrosion resistance of SKD 61 steel. Plasma nitrocarburizing was conducted for 12 h at 540℃ in the nitrogen,hydrogen and methane atmosphere to produce the ε-Fe,2-3(N,C) phase. The compound layer produced by plasma nitrocarburising was predominantly composed of ε-phase, with a small proportion of γ′-Fe4(N,C) phase.The thickness of the compound layer and the diffusion layer are about 10 μm and about 200μm, respectively.Plasma post oxidation was performed on the nitrocarburized samples with various oxygen/hydrogen ratio at constant temperature of 500℃ for 1 h. The very thin magnetite (Fe3O4) layer of 1-2μm in thickness on top of the compound layer was obtained. Anodic polarization test revealed that plasma nitrocarburizing process contributed a significant improvement of corrosion resistance of SKD 61 steel. However, the corrosion characteristics of the nitrocarburized compound layer was deteriorated by oxidation treatment.

  12. Composite electrolyte with proton conductivity for low-temperature solid oxide fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Raza, Rizwan, E-mail: razahussaini786@gmail.com [Department of Physics, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Department of Energy Technology, Royal Institute of Technology, KTH, Stockholm 10044 (Sweden); Ahmed, Akhlaq; Akram, Nadeem; Saleem, Muhammad; Niaz Akhtar, Majid; Ajmal Khan, M.; Abbas, Ghazanfar; Alvi, Farah; Yasir Rafique, M. [Department of Physics, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Sherazi, Tauqir A. [Department of Chemistry, COMSATS Institute of Information Technology, Abbotabad 22060 (Pakistan); Shakir, Imran [Sustainable Energy Technologies (SET) center, College of Engineering, King Saud University, PO-BOX 800, Riyadh 11421 (Saudi Arabia); Mohsin, Munazza [Department of Physics, Lahore College for Women University, Lahore, 54000 (Pakistan); Javed, Muhammad Sufyan [Department of Physics, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Department of Applied Physics, Chongqing University, Chongqing 400044 (China); Zhu, Bin, E-mail: binzhu@kth.se, E-mail: zhubin@hubu.edu.cn [Department of Energy Technology, Royal Institute of Technology, KTH, Stockholm 10044 (Sweden); Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Faculty of Physics and Electronic Science/Faculty of Computer and Information, Hubei University, Wuhan, Hubei 430062 (China)

    2015-11-02

    In the present work, cost-effective nanocomposite electrolyte (Ba-SDC) oxide is developed for efficient low-temperature solid oxide fuel cells (LTSOFCs). Analysis has shown that dual phase conduction of O{sup −2} (oxygen ions) and H{sup +} (protons) plays a significant role in the development of advanced LTSOFCs. Comparatively high proton ion conductivity (0.19 s/cm) for LTSOFCs was achieved at low temperature (460 °C). In this article, the ionic conduction behaviour of LTSOFCs is explained by carrying out electrochemical impedance spectroscopy measurements. Further, the phase and structure analysis are investigated by X-ray diffraction and scanning electron microscopy techniques. Finally, we achieved an ionic transport number of the composite electrolyte for LTSOFCs as high as 0.95 and energy and power density of 90% and 550 mW/cm{sup 2}, respectively, after sintering the composite electrolyte at 800 °C for 4 h, which is promising. Our current effort toward the development of an efficient, green, low-temperature solid oxide fuel cell with the incorporation of high proton conductivity composite electrolyte may open frontiers in the fields of energy and fuel cell technology.

  13. Composite electrolyte with proton conductivity for low-temperature solid oxide fuel cell

    Science.gov (United States)

    Raza, Rizwan; Ahmed, Akhlaq; Akram, Nadeem; Saleem, Muhammad; Niaz Akhtar, Majid; Sherazi, Tauqir A.; Ajmal Khan, M.; Abbas, Ghazanfar; Shakir, Imran; Mohsin, Munazza; Alvi, Farah; Javed, Muhammad Sufyan; Yasir Rafique, M.; Zhu, Bin

    2015-11-01

    In the present work, cost-effective nanocomposite electrolyte (Ba-SDC) oxide is developed for efficient low-temperature solid oxide fuel cells (LTSOFCs). Analysis has shown that dual phase conduction of O-2 (oxygen ions) and H+ (protons) plays a significant role in the development of advanced LTSOFCs. Comparatively high proton ion conductivity (0.19 s/cm) for LTSOFCs was achieved at low temperature (460 °C). In this article, the ionic conduction behaviour of LTSOFCs is explained by carrying out electrochemical impedance spectroscopy measurements. Further, the phase and structure analysis are investigated by X-ray diffraction and scanning electron microscopy techniques. Finally, we achieved an ionic transport number of the composite electrolyte for LTSOFCs as high as 0.95 and energy and power density of 90% and 550 mW/cm2, respectively, after sintering the composite electrolyte at 800 °C for 4 h, which is promising. Our current effort toward the development of an efficient, green, low-temperature solid oxide fuel cell with the incorporation of high proton conductivity composite electrolyte may open frontiers in the fields of energy and fuel cell technology.

  14. Manufacturing of Dysprosium-Iron Alloys by Electrolysis in Fluoride-Based Electrolytes: Oxide Solubility Determinations

    Science.gov (United States)

    Martinez, Ana Maria; Støre, Anne; Osen, Karen Sende

    2018-04-01

    Electrolytic production of light rare earth elements and alloys takes place in a fluoride-based electrolyte using rare earth oxides as raw material. The optimization of this method, mainly in terms of the energy efficiency and environmental impact control, is rather challenging. Anode effects, evolution of fluorine-containing compounds, and side cathode reactions could largely be minimized by a good control of the amount of rare earth oxide species dissolved in the fluoride-based electrolyte and their dissolution rate. The oxide content of the fluoride melts REF3-LiF (RE = Nd, Dy) at different compositions and temperatures were experimentally determined by carbothermal analysis of melt samples. The highest solubility values of oxide species, added as Dy2O3 and Dy2(CO3)3, were obtained to be of ca. 3 wt pct (expressed as Dy2O3) in the case of the equimolar DyF3-LiF melt at 1323 K (1050 °C). The oxide saturation values increased with the amount of REF3 present in the molten bath and the working temperature.

  15. EIS, Mott Schottky and EFM analysis of the electrochemical stability and dielectric properties of Ca-P-Ag and Ca-P-Si-Ag coatings obtained by plasma electrolytic oxidation in Ti6Al4V

    Directory of Open Access Journals (Sweden)

    Sara María Leal-Marin

    2017-01-01

    Full Text Available El Ti6Al4V ELI (ASTM F136 es una de las aleaciones más empleadas en dispositivos de osteosíntesis y reemplazo articular. Sin embargo, las propiedades de esta aleación pueden ser mejoradas respecto a su biocompatibilidad y osteointegración con el tejido óseo a través de recubrimientos. El objetivo de este trabajo fue evaluar el comportamiento electroquímico de un recubrimiento obtenido por oxidación por plasma electrolítico sobre Ti6Al4V ELI empleando soluciones electrolíticas enriquecidas con iones de PO4 2-, Ca+2, Si+4 y varias concentraciones de Ag+1. Los recubrimientos se caracterizaron mediante espectroscopia de impedancia electroquímica (EIS y Mott-Schottky (M-S en una celda de tres electrodos con una solución fisiológica simulada. El comportamiento electroquímico se contrastó con microscopía de fuerza electrostática (EFM, donde se analizó el potencial eléctrico del recubrimiento. Los resultados de EIS mostraron mejores propiedades de estabilidad frente a la corrosión en los sustratos recubiertos con Ca- P-Ag, comparados con los recubiertos con Ca-P-Si-Ag. Los espectros de Nyquist y Bode mostraron relajaciones relacionadas con la transferencia de carga hacia la doble capa electroquímica como reflejo de los cambios microestructurales y de conductividad de los recubrimientos, dada por la presencia particular en cada caso, de los elementos contenidos en estos. De acuerdo con los resultados de M-S, todas las muestras ensayadas presentaron un comportamiento con dopado tipo n, cuya conductividad incrementó con la inclusión de plata. Mediante EFM se observaron mayores contrastes en el potencial, fase y la amplitud de los recubrimientos con mayor cantidad de plata respecto al Ti6Al4V sin recubrir.

  16. Three-dimensional ionic conduction in the strained electrolytes of solid oxide fuel cells

    International Nuclear Information System (INIS)

    Han, Yupei; Zou, Minda; Lv, Weiqiang; He, Weidong; Mao, Yiwu; Wang, Wei

    2016-01-01

    Flexible power sources including fuel cells and batteries are the key to realizing flexible electronic devices with pronounced foldability. To understand the bending effects in these devices, theoretical analysis on three-dimensional (3-D) lattice bending is necessary. In this report, we derive a 3-D analytical model to analyze the effects of electrolyte crystal bending on ionic conductivity in flexible solid-state batteries/fuel cells. By employing solid oxide fuel cells as a materials' platform, the intrinsic parameters of bent electrolyte materials, including lattice constant, Young's modulus, and Poisson ratio, are evaluated. Our work facilitates the rational design of highly efficient flexible electrolytes for high-performance flexible device applications.

  17. Electrolytic photodissociation of chemical compounds by iron oxide electrodes

    Science.gov (United States)

    Somorjai, Gabor A.; Leygraf, Christofer H.

    1984-01-01

    Chemical compounds can be dissociated by contacting the same with a p/n type semi-conductor diode having visible light as its sole source of energy. The diode consists of low cost, readily available materials, specifically polycrystalline iron oxide doped with silicon in the case of the n-type semi-conductor electrode, and polycrystalline iron oxide doped with magnesium in the case of the p-type electrode. So long as the light source has an energy greater than 2.2 electron volts, no added energy source is needed to achieve dissociation.

  18. Peroxynitrite-mediated oxidation of plasma fibronectin

    DEFF Research Database (Denmark)

    Degendorfer, Georg; Chuang, Christine Y; Kawasaki, Hiroaki

    2016-01-01

    Fibronectin is a large dimeric glycoprotein present in both human plasma and in basement membranes. The latter are specialized extracellular matrices underlying endothelial cells in the artery wall. Peroxynitrous acid (ONOOH) a potent oxidizing and nitrating agent, is formed in vivo from superoxide...... and nitric oxide radicals by stimulated macrophages and other cells. Considerable evidence supports ONOOH involvement in human atherosclerotic lesion development and rupture, possibly via extracellular matrix damage. Here we demonstrate that Tyr and Trp residues on human plasma fibronectin are highly...

  19. Solid polymer electrolyte composite membrane comprising a porous support and a solid polymer electrolyte including a dispersed reduced noble metal or noble metal oxide

    Science.gov (United States)

    Liu, Han; Mittelsteadt, Cortney K; Norman, Timothy J; Griffith, Arthur E; LaConti, Anthony B

    2015-02-24

    A solid polymer electrolyte composite membrane and method of manufacturing the same. According to one embodiment, the composite membrane comprises a thin, rigid, dimensionally-stable, non-electrically-conducting support, the support having a plurality of cylindrical, straight-through pores extending perpendicularly between opposing top and bottom surfaces of the support. The pores are unevenly distributed, with some or no pores located along the periphery and more pores located centrally. The pores are completely filled with a solid polymer electrolyte, the solid polymer electrolyte including a dispersed reduced noble metal or noble metal oxide. The solid polymer electrolyte may also be deposited over the top and/or bottom surfaces of the support.

  20. Photoelectrolysis at the oxide-electrolyte interface as interpreted through the 'transition' layer model

    Science.gov (United States)

    Kalia, R. K.; Weber, Michael F.; Schumacher, L.; Dignam, M. J.

    1980-12-01

    A transition layer model of the oxide-electrolyte interface, proposed earlier by one of us, is outlined and then examined in the light of experimental data relating primarily to photoelectrolysis of water at semiconducting oxide electrodes. The model provides useful insight into the behaviour of the system and allows a calculation of thc minimum bias potential needed for photoelectrolysis, thus illuminating the origin of the requirement for such an external bias. In order to electrolyse water without a bias, the model requires an n-type oxide to be sufficiently reduced so that it is thermodynamically capable of chemically reducing water to produce hydrogen at 1 atm pressure. Similarly, for bias-free operation, a p-type metal oxide must be thermodynamically unstable with respect to the release of oxygen at 1 atm pressure. In the face of these requirements it is apparent that oxide stability is bound to be in general a serious problem for nonstoichiometric single metal oxides.

  1. Lanthanum gallate and ceria composite as electrolyte for solid oxide fuel cells

    International Nuclear Information System (INIS)

    Li Shuai; Li Zhicheng; Bergman, Bill

    2010-01-01

    The composite of doped lanthanum gallate (La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 2.85 , LSGM) and doped ceria (Ce 0.8 Sm 0.2 O 1.9 , CSO) was investigated as an electrolyte for solid oxide fuel cell (SOFC). The LSGM-CSO composite was examined by X-ray diffraction (XRD) and impedance spectroscopy. It was found that the sintered LSGM-CSO composite contains mainly fluorite CeO 2 phase and a minority impurity phase, Sm 3 Ga 5 O 12 . The LSGM-CSO composite electrolyte shows a small grain boundary response in the impedance spectroscopy as compared to LSGM and CSO pellets. The composite electrolyte exhibits the highest conductivity in the temperature range of 250-600 o C, compared to LSGM and CSO. The LSGM-CSO composite can be expected to be an attractive intermediate temperature electrolyte material for solid oxide fuel cells.

  2. Lanthanum gallate and ceria composite as electrolyte for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Li Shuai, E-mail: shuail@kth.s [Department of Materials Science and Engineering, School of Industrial Engineering and Management, Royal Institute of Technology, SE 10044 Stockholm (Sweden); Li Zhicheng [School of Materials Science and Engineering, Central South University, 410083 Changsha, Hunan (China); Bergman, Bill [Department of Materials Science and Engineering, School of Industrial Engineering and Management, Royal Institute of Technology, SE 10044 Stockholm (Sweden)

    2010-03-04

    The composite of doped lanthanum gallate (La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 2.85}, LSGM) and doped ceria (Ce{sub 0.8}Sm{sub 0.2}O{sub 1.9}, CSO) was investigated as an electrolyte for solid oxide fuel cell (SOFC). The LSGM-CSO composite was examined by X-ray diffraction (XRD) and impedance spectroscopy. It was found that the sintered LSGM-CSO composite contains mainly fluorite CeO{sub 2} phase and a minority impurity phase, Sm{sub 3}Ga{sub 5}O{sub 12}. The LSGM-CSO composite electrolyte shows a small grain boundary response in the impedance spectroscopy as compared to LSGM and CSO pellets. The composite electrolyte exhibits the highest conductivity in the temperature range of 250-600 {sup o}C, compared to LSGM and CSO. The LSGM-CSO composite can be expected to be an attractive intermediate temperature electrolyte material for solid oxide fuel cells.

  3. Fabrication of thin yttria-stabilized-zirconia dense electrolyte layers by inkjet printing for high performing solid oxide fuel cells

    DEFF Research Database (Denmark)

    Esposito, Vincenzo; Gadea, Christophe; Hjelm, Johan

    2015-01-01

    In this work, we present how a low-cost HP Deskjet 1000 inkjet printer was used to fabricate a 1.2 mm thin, dense and gas tight 16 cm2 solid oxide fuel cells (SOFC) electrolyte. The electrolyte was printed using an ink made of highly diluted (

  4. Materials system for intermediate temperature solid oxide fuel cells based on doped lanthanum-gallate electrolyte

    Science.gov (United States)

    Gong, Wenquan

    2005-07-01

    The objective of this work was to identify a materials system for intermediate temperature solid oxide fuel cells (IT-SOFCs). Towards this goal, alternating current complex impedance spectroscopy was employed as a tool to study electrode polarization effects in symmetrical cells employing strontium and magnesium doped lanthanum gallate (LSGM) electrolyte. Several cathode materials were investigated including strontium doped lanthanum manganite (LSM), Strontium and iron doped lanthanum cobaltate (LSCF), LSM-LSGM, and LSCF-LSGM composites. Investigated Anode materials included nickel-gadolinium or lanthanum doped cerium oxide (Ni-GDC, or Ni-LDC) composites. The ohmic and the polarization resistances of the symmetrical cells were obtained as a function of temperature, time, thickness, and the composition of the electrodes. Based on these studies, the single phase LSM electrode had the highest polarization resistance among the cathode materials. The mixed-conducting LSCF electrode had polarization resistance orders of magnitude lower than that of the LSM-LSGM composite electrodes. Although incorporating LSGM in the LSCF electrode did not reduce the cell polarization resistance significantly, it could reduce the thermal expansion coefficient mismatch between the LSCF electrodes and LSGM electrolyte. Moreover, the polarization resistance of the LSCF electrode decreased asymptotically as the electrode thickness was increased thus suggesting that the electrode thickness needed not be thicker than this asymptotic limit. On the anode side of the IT-SOFC, Ni reacted with LSGM electrolyte, and lanthanum diffusion occurred from the LSGM electrolyte to the GDC barrier layer, which was between the LSGM electrolyte and the Ni-composite anode. However, LDC served as an effective barrier layer. Ni-LDC (70 v% Ni) anode had the largest polarization resistance, while all other anode materials, i.e. Ni-LDC (50 v% Ni), Ni-GDC (70 v% NO, and Ni-GDC (50 v% Ni), had similar polarization

  5. Influence of exercise on plasma ammonia and urea after ingestion beverages of carbohydrate electrolyte

    Science.gov (United States)

    Rusip, Gusbakti; Mukti Suhartini, Sri; Boon Suen, Ang

    2018-03-01

    Ingestion of beverages with carbohydrate electrolyte during exercise can delay fatigue. Fatigue caused by the decreasing of glycogen deposit source and indefensible reproduced ATP result in the improvement of IMP and ammonia during fatigue. The aim of this research was to observe the alteration of plasma ammonia and urea before, during and after exercise, after ingestion beverages of carbohydrate - electrolyte. Ten male subjects (age 18-30 years) were subjected to there cycle ergometer at 60% of VO2max with a pedal speed of 60 rpm until there is fatigued. The subject was given a drink of carbohydrate-electrolyte at a concentration of 6%, 12% and a flavored water placebo (P) to consume the volume of 3 ml/kg BW every 20 minutes. Blood samples were taken at rest and every 20 minutes until fatigue for analyzing plasma ammonia and urea. Mean exercise until fatigue show that no difference for three beverages. However, plasma ammonia and urea were significantly increase compared before and after exercise (pexercise for beverages CHO 12% (HC) (31.86±1.93μml/l vs 86.50±5.13μml/l), for CHO 6% (MC) (33.08±1.43μml/l vs 90.68±3.41μml/l), for no carbohydrate (P) (33.64±1.93μml/l vs 93.12 ± 2.91μml/l). Whereas plasma urea before exercise for beverages CHO 12% (4.75±0.12mmol/l vs 5.44±0.10mmol/l), for CHO 6% (4.88±0.20mmol/l vs 5.22± 0.10mmol/l), for Placebo (4.88±0.20mmol/l vs 5.54±0.24mmol/l). Conclusions that increase of plasma ammonia of during fatigue, can become the criteria for determining intensity exercise until fatigue results are better than plasma lactate.

  6. Oxidative degradation of polybenzimidazole membranes as electrolytes for high temperature proton exchange membrane fuel cells

    DEFF Research Database (Denmark)

    Liao, J.H.; Li, Qingfeng; Rudbeck, H.C.

    2011-01-01

    the oxidative degradation of the polymer membrane was studied under the Fenton test conditions by the weight loss, intrinsic viscosity, size exclusion chromatography, scanning electron microscopy and Fourier transform infrared spectroscopy. During the Fenton test, significant weight losses depending...... on the initial molecular weight of the polymer were observed. At the same time, viscosity and SEC measurements revealed a steady decrease in molecular weight. The degradation of acid doped PBI membranes under Fenton test conditions is proposed to start by the attack of hydroxyl radicals at the carbon atom......Polybenzimidazole membranes imbibed with acid are emerging as a suitable electrolyte material for high-temperature polymer electrolyte fuel cells. The oxidative stability of polybenzimidazole has been identified as an important issue for the long-term durability of such cells. In this paper...

  7. Some regularities in aging of solid oxide electrolytes ZrO2+Y2O3

    International Nuclear Information System (INIS)

    Vlasov, A.N.

    1983-01-01

    A study was made on the temperature effect on the rate and depth of aging of solid oxide electrolytes ZrO 2 +Y 2 O 3 and ZrO 2 +Ho 2 O 3 , stabilized by 10-15 mol.% R 2 O 3 following isothermal hold-up during 2000-3000 h in the 725-1550 deg C range in oxidizing medium. It was shown that solid electrolyte aging proceeds only at temperatures below a certain boundary value. The depth of complete aging at that increases with the R 2 O 3 concentration and a temperature decrease. The aging rate depends substantially on both temperature and concentration of a stabilizing addition. A decrease in the electric conductivity with time is accompanied by an increase in the conductivity activation energy

  8. Mediated electrochemical oxidation of organic wastes using a Co(III) mediator in a neutral electrolyte

    International Nuclear Information System (INIS)

    Balazs, G.B.; Lewis, P.R.

    1999-01-01

    An electrochemical cell with a Co(III) mediator and neutral pH anolyte provides efficient destruction of organic and mixed wastes. The organic waste is concentrated in the anolyte reservoir, where the cobalt mediator oxidizes the organics and insoluble radioactive species and is regenerated at the anode until all organics are converted to carbon dioxide and destroyed. The neutral electrolyte is non-corrosive, and thus extends the lifetime of the cell and its components. 2 figs

  9. Modifying zirconia solid electrolyte surface property to enhance oxide transport

    Energy Technology Data Exchange (ETDEWEB)

    Liaw, B.Y.; Song, S.Y. [Univ. of Hawaii, Honolulu, HI (United States)

    1996-12-31

    Bismuth-strontium-calcium-copper oxide (Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8}, BSCCO) is known for its high T{sub c} superconducting behavior and mixed conducting property. The applicability of similar high T{sub c} cuprates for intermediate-temperature solid oxide fuel cell (SOFC) application has been studied recently. We investigated the electrochemical behavior of several Ag{vert_bar}BSCCO{vert_bar}10 mol% yttria-stabilized zirconia (YSZ){vert_bar}Ag and Ag{vert_bar}YSZ{vert_bar}Ag cells using complex impedance spectroscopy. A highly uniform and porous microstructure was observed at the interface of the YSZ and BSCCO. The ionic conductivity determined from the Nyquest plots in the temperature range of 200-700{degrees}C agrees with the values reported in the literature. The specific resistance of the BSCCO{vert_bar}YSZ interface was also determined to be lower than those of the conventional manganite electrode, suggesting that BSCCO seems attractive for cathode applications in SOFC.

  10. Ionic conductivity in polyethylene-b-poly(ethylene oxide)/lithium perchlorate solid polymer electrolytes

    International Nuclear Information System (INIS)

    Guilherme, L.A.; Borges, R.S.; Moraes, E. Mara S.; Silva, G. Goulart; Pimenta, M.A.; Marletta, A.; Silva, R.A.

    2007-01-01

    The ionic conductivity and phase arrangement of solid polymeric electrolytes based on the block copolymer polyethylene-b-poly(ethylene oxide) (PE-b-PEO) and LiClO 4 have been investigated. One set of electrolytes was prepared from copolymers with 75% of PEO units and another set was based on a blend of copolymer with 50% PEO units and homopolymers. The differential scanning calorimetry (DSC) results, for electrolytes based on the copolymer with 75% of PEO units, were dominated by the PEO phase. The PEO block crystallinity dropped and the glass transition increased with salt addition due to the coordination of the cation by PEO oxygen. The conductivity for copolymers 75% PEO-based electrolyte with 15 wt% of salt was higher than 10 -5 S/cm at room temperature and reached to 10 -3 S/cm at 100 deg. C on a heating measurement. The blend of PE-b-PEO (50% PEO)/PEO/PE showed a complex thermal behavior with decoupled melting of the blocks and the homopolymers. Upon salt addition the endotherms associated with PEO domains disappeared and the PE crystals remained untouched. The conductivity results were limited at 100 deg. C to values close to 10 -4 S/cm and at room temperature values close to 3 x 10 -6 S/cm were obtained for the 15 wt% salt electrolyte. Raman study showed that the ionic association of the highly concentrated blend electrolytes at room temperature is not significant. Therefore, the lower values of conductivity in the case of the blend with 50% PEO can be assigned to the higher content of PE domains leading to a morphology with lower connectivity for ionic conduction both in the crystalline and melted state of the PE domains

  11. Anti-corrosion layer prepared by plasma electrolytic carbonitriding on pure aluminum

    International Nuclear Information System (INIS)

    Wu, Jie; Zhang, Yifan; Liu, Run; Wang, Bin; Hua, Ming; Xue, Wenbin

    2015-01-01

    Highlights: • PEC/N can be applied to low melting point metal. • The spectroscopic characterization of plasma discharge is investigated. • Electron concentration and electron temperature are evaluated for PEC/N. • Phase composition of the carbonitrided layer is determined. • PEC/N improves the corrosion resistance of aluminum greatly. - Abstract: In this paper, plasma electrolytic carbonitriding (PEC/N) method was applied to pure aluminum for the first time. The spectroscopic characterization of plasma discharge during PEC/N process was analyzed and the electron temperature was calculated in terms of optical emission spectroscopy. The results showed the discharge plasma was in local thermal equilibrium (LTE) state. Electron concentration and electron temperature were about 6 × 10 21 m −3 and 4000 K, respectively. The carbonitrided layer contained Al 4 C 3 , AlN and Al 7 C 3 N 3 phases. After PEC/N treatment, the corrosion resistance of pure aluminum was significantly improved, which was related to the formation of nitride phases. This work expands the application of plasma electrolysis technology on the surface modification of low melting point metal

  12. Anti-corrosion layer prepared by plasma electrolytic carbonitriding on pure aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jie; Zhang, Yifan; Liu, Run; Wang, Bin; Hua, Ming [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Xue, Wenbin, E-mail: xuewb@bnu.edu.cn [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

    2015-08-30

    Highlights: • PEC/N can be applied to low melting point metal. • The spectroscopic characterization of plasma discharge is investigated. • Electron concentration and electron temperature are evaluated for PEC/N. • Phase composition of the carbonitrided layer is determined. • PEC/N improves the corrosion resistance of aluminum greatly. - Abstract: In this paper, plasma electrolytic carbonitriding (PEC/N) method was applied to pure aluminum for the first time. The spectroscopic characterization of plasma discharge during PEC/N process was analyzed and the electron temperature was calculated in terms of optical emission spectroscopy. The results showed the discharge plasma was in local thermal equilibrium (LTE) state. Electron concentration and electron temperature were about 6 × 10{sup 21} m{sup −3} and 4000 K, respectively. The carbonitrided layer contained Al{sub 4}C{sub 3}, AlN and Al{sub 7}C{sub 3}N{sub 3} phases. After PEC/N treatment, the corrosion resistance of pure aluminum was significantly improved, which was related to the formation of nitride phases. This work expands the application of plasma electrolysis technology on the surface modification of low melting point metal.

  13. Improving cyclic stability of lithium nickel manganese oxide cathode for high voltage lithium ion battery by modifying electrode/electrolyte interface with electrolyte additive

    International Nuclear Information System (INIS)

    Li, Bin; Wang, Yaqiong; Tu, Wenqiang; Wang, Zaisheng; Xu, Mengqing; Xing, Lidan; Li, Weishan

    2014-01-01

    Highlights: • Cyclic stability of LiNi 0.5 Mn 1.5 O 4 is improved significantly by using PES as additive. • A protective SEI is formed on LiNi 0.5 Mn 1.5 O 4 due to the preferential oxidation of PES. • The SEI suppresses electrolyte decomposition and structure destruction of LiNi 0.5 Mn 1.5 O 4 . - Abstract: We report a new approach to improve the cyclic stability of lithium nickel manganese oxide (LiNi 0.5 Mn 1.5 O 4 ) cathode, in which the cathode/electrolyte interface is modified by using prop-1-ene-1, 3-sultone (PES) as an electrolyte additive. The interfacial properties of LiNi 0.5 Mn 1.5 O 4 cathode in PES-containing electrolyte have been investigated by scanning electron spectroscopy (SEM), transmission electron microscopy (TEM), thermal gravimetry (TG), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), cyclic voltammometry (CV), chronoamperometry (CA), and constant current charge/discharge test. It is found that the application of PES improves significantly the cyclic stability of LiNi 0.5 Mn 1.5 O 4 . After 400 cycles at 1C rate (1C=147 mA g −1 ), the capacity retention of LiNi 0.5 Mn 1.5 O 4 is 90% for the cell using 1.0 wt% PES, while only 49% for the cell without the additive. The characterizations from SEM, TEM, TG, XRD, and XPS confirm that the LiNi 0.5 Mn 1.5 O 4 /electrolyte interface is modified and a protective solid electrolyte interface film is formed on LiNi 0.5 Mn 1.5 O 4 particles, which prevents LiNi 0.5 Mn 1.5 O 4 from destruction and suppresses the electrolyte decomposition

  14. Reoxidation of uranium in electrolytically reduced simulated oxide fuel during residual salt distillation

    International Nuclear Information System (INIS)

    Eun-Young Choi; Jin-Mok Hur; Min Ku Jeon; University of Science and Technology, Yuseong-gu, Daejeon

    2017-01-01

    We report that residual salt removal by high-temperature distillation causes partial reoxidation of uranium metal to uranium oxide in electrolytically reduced simulated oxide fuel. Specifically, the content of uranium metal in the above product decreases with increasing distillation temperatures, which can be attributed to reoxidation by Li 2 O contained in residual salt (LiCl). Additionally, we estimate the fractions of Li 2 O reacted with uranium metal under these conditions, showing that they decrease with decreasing temperature, and calculate some thermodynamic parameters of the above reoxidation. (author)

  15. Tantalum oxide-based compounds as new non-noble cathodes for polymer electrolyte fuel cell

    International Nuclear Information System (INIS)

    Ishihara, Akimitsu; Tamura, Motoko; Matsuzawa, Koichi; Mitsushima, Shigenori; Ota, Ken-ichiro

    2010-01-01

    Tantalum oxide-based compounds were examined as new non-noble cathodes for polymer electrolyte fuel cell. Tantalum carbonitride powder was partially oxidized under a trace amount of oxygen gas at 900 o C for 4 or 8 h. Onset potential for oxygen reduction reaction (ORR) of the specimen heat-treated for 8 h was 0.94 V vs. reversible hydrogen electrode in 0.1 mol dm -3 sulfuric acid at 30 o C. The partial oxidation of tantalum carboniride was effective to enhance the catalytic activity for the ORR. The partially oxidized specimen with highest catalytic activity had ca. 5.25 eV of ionization potential, indicating that there was most suitable strength of the interaction of oxygen and tantalum on the catalyst surface.

  16. A Study on the Electrolytic Reduction Mechanism of Uranium Oxide in a LiCl-Li2O Molten Salt

    International Nuclear Information System (INIS)

    Oh, Seung Chul; Hur, Jin Mok; Seo, Chung Seok; Park, Seong Won

    2003-01-01

    This study proposed a new electrolytic reduction technology that is based on the integration of simultaneous uranium oxide metallization and Li 2 O electrowinning. In this electrolytic reduction reaction, electrolytically reduced Li deposits on cathode and simultaneously reacts with uranium oxides to produce uranium metal showing more than 99% conversion. For the verification of process feasibility, the experiments to obtain basic data on the metallization of uranium oxide, investigation of reaction mechanism, the characteristics of closed recycle of Li 2 O and mass transfer were carried out. This evolutionary electrolytic reduction technology would give benefits over the conventional Li-reduction process improving economic viability such as: avoidance of handling of chemically active Li-LiCl molten salt increase of metallization yield, and simplification of process.

  17. A study on the electrolytic reduction of uranium oxide in a LiCl-Li2O molten salt

    International Nuclear Information System (INIS)

    Su, J. S.; Hu, J. M.; Hong, S. S.; Jang, D. S.; Park, S. W.

    2003-01-01

    New electrolytic reduction technology was proposed that is based on the integration of metallization of uranium oxide and Li 2 O electrowinning. In this electrolytic reduction reaction, electrolytically reduced Li deposits on cathode and simultaneously reacts with uranium oxides to produce uranium metal showing more than 99% conversion. For the verification of process feasibility, the experiments to obtain basic data on the metallization of uranium oxide, investigation of reaction mechanism, the characteristics of closed recycle of Li 2 O and mass transfer were carried out. This evolutionary electrolytic reduction technology would give benefits over the conventional Li-reduction process improving economic viability such as: avoidance of handling of chemically active Li-LiCl molten salt, increase of metallization yield, and simplification of process

  18. Surface Properties of PAN-based Carbon Fibers Modified by Electrochemical Oxidization in Organic Electrolyte Systems

    Directory of Open Access Journals (Sweden)

    WU Bo

    2016-09-01

    Full Text Available PAN-based carbon fibers were modified by electrochemical oxidization using fatty alcohol polyoxyethylene ether phosphate (O3P, triethanolamine (TEOA and fatty alcohol polyoxyethylene ether ammonium phosphate (O3PNH4 as organic electrolyte respectively. Titration analysis, single fiber fracture strength measurement and field emission scanning electron microscopy (FE-SEM were used to evaluate the content of acidic functional group on the surface, mechanical properties and surface morphology of carbon fiber. The optimum process of electrochemical treatment obtained is at 50℃ for 2min and O3PNH4 (5%, mass fraction as the electrolyte with current density of 2A/g. In addition, the surface properties of modified carbon fibers were characterized by X-ray photoelectron spectroscopy (XPS and single fiber contact angle test. The results show that the hydrophilic acidic functional groups on the surface of carbon fiber which can enhance the surface energy are increased by the electrochemical oxidation using O3PNH4 as electrolyte, almost without any weakening to the mechanical properties of carbon fiber.

  19. For cermet inert anode containing oxide and metal phases useful for the electrolytic production of metals

    Science.gov (United States)

    Ray, Siba P.; Liu, Xinghua; Weirauch, Douglas A.

    2002-01-01

    A cermet inert anode for the electrolytic production of metals such as aluminum is disclosed. The inert anode comprises a ceramic phase including an oxide of Ni, Fe and M, where M is at least one metal selected from Zn, Co, Al, Li, Cu, Ti, V, Cr, Zr, Nb, Ta, W, Mo, Hf and rare earths, preferably Zn and/or Co. Preferred ceramic compositions comprise Fe.sub.2 O.sub.3, NiO and ZnO or CoO. The cermet inert anode also comprises a metal phase such as Cu, Ag, Pd, Pt, Au, Rh, Ru, Ir and/or Os. A preferred metal phase comprises Cu and Ag. The cermet inert anodes may be used in electrolytic reduction cells for the production of commercial purity aluminum as well as other metals.

  20. Oxide-ion and proton conducting electrolyte materials for clean energy applications: structural and mechanistic features.

    Science.gov (United States)

    Malavasi, Lorenzo; Fisher, Craig A J; Islam, M Saiful

    2010-11-01

    This critical review presents an overview of the various classes of oxide materials exhibiting fast oxide-ion or proton conductivity for use as solid electrolytes in clean energy applications such as solid oxide fuel cells. Emphasis is placed on the relationship between structural and mechanistic features of the crystalline materials and their ion conduction properties. After describing well-established classes such as fluorite- and perovskite-based oxides, new materials and structure-types are presented. These include a variety of molybdate, gallate, apatite silicate/germanate and niobate systems, many of which contain flexible structural networks, and exhibit different defect properties and transport mechanisms to the conventional materials. It is concluded that the rich chemistry of these important systems provides diverse possibilities for developing superior ionic conductors for use as solid electrolytes in fuel cells and related applications. In most cases, a greater atomic-level understanding of the structures, defects and conduction mechanisms is achieved through a combination of experimental and computational techniques (217 references).

  1. Alkyl Substitution Effect on Oxidation Stability of Sulfone-Based Electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Su, Chi-Cheung [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Ave. Argonne IL 60439 USA; He, Meinan [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Ave. Argonne IL 60439 USA; Redfern, Paul [Materials Science Division, Argonne National Laboratory, 9700 S. Cass Ave. Argonne IL 60439 USA; Curtiss, Larry A. [Materials Science Division, Argonne National Laboratory, 9700 S. Cass Ave. Argonne IL 60439 USA; Liao, Chen [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Ave. Argonne IL 60439 USA; Zhang, Lu [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Ave. Argonne IL 60439 USA; Burrell, Anthony K. [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Ave. Argonne IL 60439 USA; Zhang, Zhengcheng [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Ave. Argonne IL 60439 USA

    2016-02-16

    Organic sulfone compounds have been widely used as high-voltage electrolytes for lithium-ion batteries for decades. However, owing to the complexity of the synthesis of new sulfones, only a few commercially available sulfones have been studied. In this paper, we report the synthesis of new sulfone compounds with various substituent groups and the impact of the substituent group on the oxidation stability of sulfones. Electrochemical floating tests using a 5 V LiNi0.5Mn1.5O4 spinel cathode and density functional theory calculations showed that the cyclopentyl-substituted sulfone McPS suffered from oxidation instability, starting from 4.9 V versus Li+/Li, as observed by the large leakage currents. On the other hand, the isopropyl-substituted sulfone MiPS and tetramethylene substituted sulfone TMS showed much improved oxidation stability under identical testing conditions. The substitution structure of the sulfone plays a significant role in the determination of its oxidative stability and should first be considered for the development of new sulfone-based electrolytes for high-voltage, high-energy lithium-ion batteries.

  2. Modification of polycarbonate surface in oxidizing plasma

    Science.gov (United States)

    Ovtsyn, A. A.; Smirnov, S. A.; Shikova, T. G.; Kholodkov, I. V.

    2017-11-01

    The properties of the surface of the film polycarbonate Lexan 8010 were experimentally studied after treatment in a DC discharge plasma in oxygen and air at pressures of 50-300 Pa and a discharge current of 80 mA. The contact angles of wetting and surface energies are measured. The topography of the surface was investigated by atomic force microscopy. The chemical composition of the surface was determined from the FT-IR spectroscopy data in the variant of total internal reflection, as well as X-ray photoelectron spectroscopy. Treatment in the oxidizing plasma leads to a change in morphology (average roughness increases), an increase in the surface energy, and the concentration of oxygen-containing groups (hydroxyl groups, carbonyl groups in ketones or aldehydes and in oxyketones) on the surface of the polymer. Possible reasons for the difference in surface properties of polymer under the action of oxygen and air plasma on it are discussed.

  3. Non-thermal Plasma and Oxidative Stress

    Science.gov (United States)

    Toyokuni, Shinya

    2015-09-01

    Thermal plasmas and lasers have been used in medicine to cut and ablate tissues and for coagulation. Non-equilibrium atmospheric pressure plasma (NEAPP; non-thermal plasma) is a recently developed, non-thermal technique with possible biomedical applications. Although NEAPP reportedly generates reactive oxygen/nitrogen species, electrons, positive ions, and ultraviolet radiation, few research projects have been conducted to merge this technique with conventional free radical biology. Recently, Prof. Masaru Hori's group (Plasma Nanotechnology Research Center, Nagoya University) developed a NEAPP device with high electron density. Here electron spin resonance revealed hydroxyl radicals as a major product. To merge non-thermal plasma biology with the preexisting free radical biology, we evaluated lipid peroxidation and DNA modifications in various in vitro and ex vivo experiments. Conjugated dienes increased after exposure to linoleic and alfa-linolenic acids. An increase in 2-thiobarbituric acid-reactive substances was also increased after exposure to phosphatidylcholine, liposomes or liver homogenate. Direct exposure to rat liver in medium produced immunohistochemical evidence of 4-hydroxy-2-nonenal- and acrolein-modified proteins. Exposure to plasmid DNA induced dose-dependent single/double strand breaks and increased the amounts of 8-hydroxy-2'-deoxyguanosine and cyclobutane pyrimidine dimers. These results indicate that oxidative biomolecular damage by NEAPP is dose-dependent and thus can be controlled in a site-specific manner. Simultaneous oxidative and UV-specific DNA damage may be useful in cancer treatment. Other recent advancements in the related studies of non-thermal plasma in Nagoya University Graduate School of Medicine will also be discussed.

  4. A modified anode/electrolyte structure for a solid oxide electrochemical cell and a method for making said structure

    DEFF Research Database (Denmark)

    2013-01-01

    -stabilised zirconium oxide electrolyte and (c) a metallic and/or a ceramic electrocatalyst in the shape of interlayers incorporated in the interface between the anode and the electrolyte. This assembly is first sintered at a given temperature and then at a lower temperature in reducing gas mixtures. These heat...... treatments resulted in a distribution of the metallic and/or ceramic interlayers in the electrolyte/anode backbone junction taking place. The structure is prepared by (a) depositing a ceramic interlayer onto one side of the electrolyte, (b) optionally applying a metallic interlayer thereon, (c) repeating...... steps (a) and (b), (d) applying a layer of the selected anode backbone onto the electrolyte with applied interlayers, (e) sintering the raw assembly and (f) infiltrating the electrocatalyst precursor into the sintered assembly and heat treating the assembly to incorporate additional electrocatalyst...

  5. Changes in mechanical properties and structure of electrolytic plasma treated X 12 CrNi 18 10 Ti stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Kurbanbekov, Sherzod; Baklanov, Viktor; Karakozov, Batyrzhan [Republican State Enterprise National Nuclear Center of Kazakhstan, Kurchatov (Kazakhstan). Inst. of Atomic Energy Branch; Skakov, Mazhyn [Republican State Enterprise National Nuclear Center of Kazakhstan, Kurchatov (Kazakhstan)

    2017-05-01

    The paper addresses findings regarding the influence of electrolytic plasma treatment on the mechanical properties as well as structural and phase states of X 12 CrNi 18 10 Ti steel. Electrolytic plasma treatment is based on carburizing of stainless steel heated in electrolytes. Treatment of steel samples has been performed as follows: the samples were heated up to a temperature between 850 and 950 C and then they were cured for 7 minutes in an electrolyte of an aqueous solution containing 10 % glycerol (C{sub 3}H{sub 8}O{sub 3}) and 15 % sodium carbonate (Na{sub 2}CO{sub 3}). It is found that, after plasma electrolytic treatment, the surface of X 12 CrNi 18 10 Ti steel had a modified structure and high hardness. Increasing wear resistance of X 12 CrNi 18 10 Ti steel has been observed after carburizing and the coefficient of friction has been reduced. X-ray analysis showed that retained austenite γ-Fe is a main phase, and there are some diffraction lines of orthorhombic Fe{sub 3}C phase as well as Fe{sub 3}O{sub 4} cubic phase. It has been determined, that, after plasma electrolytic treatment, a carbide phase in the modified surface layer, irrespective of the location in the steel structure has the chemical composition Fe{sub 3}C. High concentration of carbon atoms in a solid solution based on γ- and α-iron, a large dislocation density, presence of particles of carbide phase and retained austenite layers have been found.

  6. Tungsten oxide thin films obtained by anodisation in low electrolyte concentration

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Nadja B.D. da [Centro de Ciências Químicas, Farmacêuticas e de Alimentos, Universidade Federal de Pelotas, Campus Capão do Leão, s/n, Pelotas, RS (Brazil); Pazinato, Julia C.O. [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500 Porto Alegre, RS (Brazil); Sombrio, Guilherme; Pereira, Marcelo B.; Boudinov, Henri [Instituto de Física, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500 Porto Alegre, RS (Brazil); Gündel, André; Moreira, Eduardo C. [Universidade Federal do Pampa, Travessa 45, 1650 Bagé, RS (Brazil); Garcia, Irene T.S., E-mail: irene.garcia@ufrgs.br [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500 Porto Alegre, RS (Brazil)

    2015-03-02

    Tungsten oxide nanostructured films were grown on tungsten substrates by anodisation under a fixed voltage and with sodium fluoride as electrolyte. The effect of the anion chloride and the influence of the modifying agent disodium hydrogen phosphate in the tungsten oxide films were also investigated. The structural characterisation of the films was performed by scanning electron microscopy, atomic force microscopy and Raman spectroscopy. The band gap was determined through diffuse reflectance spectroscopy. The thin films were photoluminescent and emitted in the range of 300 to 630 nm when irradiated at 266 nm. The synthesised films efficiently degraded of methyl orange dye in the presence of hydrogen peroxide and 250 nm radiation. The modifying agent was responsible for the improvement of the photocatalytic activity. Films with similar photocatalytic performance were obtained when the system sodium fluoride and disodium hydrogen phosphate were replaced by sodium chloride. The porous structure and low band gap values were responsible for the photocatalytic behaviour. - Highlights: • Tungsten oxide thin films were obtained by anodisation of tungsten in aqueous media. • The performance of the NaCl, NaF and NaF/Na{sub 2}HPO{sub 4} as electrolytes was investigated. • The relation between structure and optical behaviour has been discussed. • Films obtained with NaCl and NaF/Na{sub 2}HPO{sub 4} present similar photocatalytic activity.

  7. Methods for using novel cathode and electrolyte materials for solid oxide fuel cells and ion transport membranes

    Science.gov (United States)

    Jacobson, Allan J.; Wang, Shuangyan; Kim, Gun Tae

    2016-01-12

    Methods using novel cathode, electrolyte and oxygen separation materials operating at intermediate temperatures for use in solid oxide fuel cells and ion transport membranes include oxides with perovskite related structures and an ordered arrangement of A site cations. The materials have significantly faster oxygen kinetics than in corresponding disordered perovskites.

  8. A Hydrogen-Evolving Hybrid-Electrolyte Battery with Electrochemical/Photoelectrochemical Charging from Water Oxidation.

    Science.gov (United States)

    Jin, Zhaoyu; Li, Panpan; Xiao, Dan

    2017-02-08

    Decoupled hydrogen and oxygen production were successfully embedded into an aqueous dual-electrolyte (acid-base) battery for simultaneous energy storage and conversion. A three-electrode configuration was adopted, involving an electrocatalytic hydrogen-evolving electrode as cathode, an alkaline battery-type or capacitor-type anode as shuttle, and a charging-assisting electrode for electro-/photoelectrochemically catalyzing water oxidation. The conceptual battery not only synergistically outputs electricity and chemical fuels with tremendous specific energy and power densities, but also supports various approaches to be charged by pure or solar-assisted electricity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Inorganic proton conducting electrolyte coupled oxide-based dendritic transistors for synaptic electronics.

    Science.gov (United States)

    Wan, Chang Jin; Zhu, Li Qiang; Zhou, Ju Mei; Shi, Yi; Wan, Qing

    2014-05-07

    Ionic/electronic hybrid devices with synaptic functions are considered to be the essential building blocks for neuromorphic systems and brain-inspired computing. Here, artificial synapses based on indium-zinc-oxide (IZO) transistors gated by nanogranular SiO2 proton-conducting electrolyte films are fabricated on glass substrates. Spike-timing dependent plasticity and paired-pulse facilitation are successfully mimicked in an individual bottom-gate transistor. Most importantly, dynamic logic and dendritic integration established by spatiotemporally correlated spikes are also mimicked in dendritic transistors with two in-plane gates as the presynaptic input terminals.

  10. Sensing sulfur oxides and other sulfur bearing pollutants with solid electrolyte pellets. I. Gas concentration cells

    Energy Technology Data Exchange (ETDEWEB)

    Chamberland, A M; Gauthier, J M

    1977-01-01

    A new sensing technique using a solid electrolyte has been demonstrated for sulfur-bearing pollutants. Based on potentiometric measurements across a pellet of potassium sulfate, this sensor allows concentrations of sulfur dioxides, sulfur trioxide, hydrogen sulfide, methyl mercaptan and carbonyl sulfide in air to be measured with accuracy. Its operational concentration range at the present time is 0.1 ppM up to at least 10,000 ppM. The presence of other common pollutants such as carbon dioxide, methane, nitric oxide and nitrogen dioxide does not interfere with the measurement of air samples containing sulfur-bearing pollutants.

  11. Stability study of cermet-supported solid oxide fuel cells with bi-layered electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xinge; Gazzarri, Javier; Robertson, Mark; Deces-Petit, Cyrille [National Research Council, Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, BC (Canada); Kesler, Olivera [Department of Mechanical and Industrial Engineering, University of Toronto, 5 King' s College Road, Toronto, ON (Canada)

    2008-12-01

    Performance and stability of five cermet-supported button-type solid oxide fuel cells featuring a bi-layered electrolyte (SSZ/SDC), an SSC cathode, and a Ni-SSZ anode, were analyzed using polarization curves, impedance spectroscopy, and post-mortem SEM observation. The cell performance degradation at 650 C in H{sub 2}/air both with and without DC bias conditions was manifested primarily as an increase in polarization resistance, approximately at a rate of 2.3 m{omega} cm{sup 2} h{sup -1} at OCV, suggesting a decrease in electrochemical kinetics as the main phenomenon responsible for the performance decay. In addition, the initial series resistance was about ten times higher than the calculated resistance corresponding to the electrolyte, reflecting a possible inter-reaction between the electrolyte layers that occurred during the sintering stage. In situ and ex situ sintered cathodes showed no obvious difference in cell performance or decay rate. The stability of the cells with and without electrical load was also investigated and no significant influence of DC bias was recorded. Based on the experimental results presented, we preliminarily attribute the performance degradation to electrochemical and microstructural degradation of the cathode. (author)

  12. Stability study of cermet-supported solid oxide fuel cells with bi-layered electrolyte

    Science.gov (United States)

    Zhang, Xinge; Gazzarri, Javier; Robertson, Mark; Decès-Petit, Cyrille; Kesler, Olivera

    Performance and stability of five cermet-supported button-type solid oxide fuel cells featuring a bi-layered electrolyte (SSZ/SDC), an SSC cathode, and a Ni-SSZ anode, were analyzed using polarization curves, impedance spectroscopy, and post-mortem SEM observation. The cell performance degradation at 650 °C in H 2/air both with and without DC bias conditions was manifested primarily as an increase in polarization resistance, approximately at a rate of 2.3 mΩ cm 2 h -1 at OCV, suggesting a decrease in electrochemical kinetics as the main phenomenon responsible for the performance decay. In addition, the initial series resistance was about ten times higher than the calculated resistance corresponding to the electrolyte, reflecting a possible inter-reaction between the electrolyte layers that occurred during the sintering stage. In situ and ex situ sintered cathodes showed no obvious difference in cell performance or decay rate. The stability of the cells with and without electrical load was also investigated and no significant influence of DC bias was recorded. Based on the experimental results presented, we preliminarily attribute the performance degradation to electrochemical and microstructural degradation of the cathode.

  13. Carbonate-linked poly(ethylene oxide) polymer electrolytes towards high performance solid state lithium batteries

    International Nuclear Information System (INIS)

    He, Weisheng; Cui, Zili; Liu, Xiaochen; Cui, Yanyan; Chai, Jingchao; Zhou, Xinhong; Liu, Zhihong; Cui, Guanglei

    2017-01-01

    The classic poly(ethylene oxide) (PEO) based solid polymer electrolyte suffers from poor ionic conductivity of ambient temperature, low lithium ion transference number and relatively narrow electrochemical window (<4.0 V vs. Li + /Li). Herein, the carbonate-linked PEO solid polymer such as poly(diethylene glycol carbonate) (PDEC) and poly(triethylene glycol carbonate) (PTEC) were explored to find out the feasibility of resolving above issues. It was proven that the optimized ionic conductivity of PTEC based electrolyte reached up to 1.12 × 10 −5 S cm −1 at 25 °C with a decent lithium ion transference number of 0.39 and a wide electrochemical window about 4.5 V vs. Li + /Li. In addition, the PTEC based Li/LiFePO 4 cell could be reversibly charged and discharged at 0.05 C-rates at ambient temperature. Moreover, the higher voltage Li/LiFe 0.2 Mn 0.8 PO 4 cell (cutoff voltage 4.35 V) possessed considerable rate capability and excellent cycling performance even at ambient temperature. Therefore, these carbonate-linked PEO electrolytes were demonstrated to be fascinating candidates for the next generation solid state lithium batteries simultaneously with high energy and high safety.

  14. Bridging Redox Species-Coated Graphene Oxide Sheets to Electrode for Extending Battery Life Using Nanocomposite Electrolyte.

    Science.gov (United States)

    Huang, Yi Fu; Ruan, Wen Hong; Lin, Dong Ling; Zhang, Ming Qiu

    2017-01-11

    Substituting conventional electrolyte for redox electrolyte has provided a new intriguing method for extending battery life. The efficiency of utilizing the contained redox species (RS) in the redox electrolyte can benefit from increasing the specific surface area of battery electrodes from the electrode side of the electrode-electrolyte interface, but is not limited to that. Herein, a new strategy using nanocomposite electrolyte is proposed to enlarge the interface with the aid of nanoinclusions from the electrolyte side. To do this, graphene oxide (GO) sheets are first dispersed in the electrolyte solution of tungstosilicic salt/lithium sulfate/poly(vinyl alcohol) (SiWLi/Li 2 SO 4 /PVA), and then the sheets are bridged to electrode, after casting and evaporating the solution on the electrode surface. By applying in situ conductive atomic force microscopy and Raman spectra, it is confirmed that the GO sheets doped with RS of SiWLi/Li 2 SO 4 can be bridged and electrically reduced as an extended electrode-electrolyte interface. As a result, the RS-coated GO sheets bridged to LiTi 2 (PO 4 ) 3 //LiMn 2 O 4 battery electrodes are found to deliver extra energy capacity (∼30 mAh/g) with excellent electrochemical cycling stability, which successfully extends the battery life by over 50%.

  15. Internal shorting and fuel loss of a low temperature solid oxide fuel cell with SDC electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xinge; Robertson, Mark; Deces-Petit, Cyrille; Qu, Wei; Kesler, Olivera; Maric, Radenka; Ghosh, Dave [Institute for Fuel Cell Innovation, National Research Council Canada, 4250 Wesbrook Mall, Vancouver, BC V6T 1W5 (Canada)

    2007-02-10

    A solid oxide fuel cell with Sm{sub 0.2}Ce{sub 0.8}O{sub 1.9} (SDC) electrolyte of 10 {mu}m in thickness and Ni-SDC anode of 15 {mu}m in thickness on a 0.8 mm thick Ni-YSZ cermet substrate was fabricated by tape casting, screen printing and co-firing. A composite cathode, 75 wt.% Sm{sub 0.5}Sr{sub 0.5}CoO{sub 3} (SSCo) + 25 wt.% SDC, approximately 50 {mu}m in thickness, was printed on the co-fired half-cell, and sintered at 950 C. The cell showed a high electrochemical performance at temperatures ranging from 500 to 650 C. Peak power density of 545 mW cm{sup -2} at 600 C was obtained. However, the cell exhibited severe internal shorting due to the mixed conductivity of the SDC electrolyte. Both the amount of water collected from the anode outlet and the open circuit voltage (OCV) indicated that the internal shorting current could reach 0.85 A cm{sup -2} or more at 600 C. Zr content inclusions were found at the surface and in the cross-section of the SDC electrolyte, which could be one of the reasons for reduced OCV and oxygen ionic conductivity. Fuel loss due to internal shorting of the thin SDC electrolyte cell becomes a significant concern when it is used in applications requiring high fuel utilization and electrical efficiency. (author)

  16. Titanium oxidation by rf inductively coupled plasma

    International Nuclear Information System (INIS)

    Valencia-Alvarado, R; López-Callejas, R; Barocio, S R; Mercado-Cabrera, A; Peña-Eguiluz, R; Muñoz-Castro, A E; Rodríguez-Méndez, B G; De la Piedad-Beneitez, A; De la Rosa-Vázquez, J M

    2014-01-01

    The development of titanium dioxide (TiO 2 ) films in the rutile and anatase phases is reported. The films have been obtained from an implantation/diffusion and sputtering process of commercially pure titanium targets, carried out in up to 500 W plasmas. The experimental outcome is of particular interest, in the case of anatase, for atmospheric pollution degradation by photocatalysis and, as to the rutile phase, for the production of biomaterials required by prosthesis and implants. The reactor employed consists in a cylindrical pyrex-like glass vessel inductively coupled to a 13.56 MHz RF source. The process takes place at a 5×10 −2 mbar pressure with the target samples being biased from 0 to -3000 V DC. The anatase phase films were obtained from sputtering the titanium targets over glass and silicon electrically floated substrates placed 2 cm away from the target. The rutile phase was obtained by implantation/diffusion on targets at about 700 °C. The plasma was developed from a 4:1 argon/oxygen mixture for ∼5 hour processing periods. The target temperature was controlled by means of the bias voltage and the plasma source power. The obtained anatase phases did not require annealing after the plasma oxidation process. The characterization of the film samples was conducted by means of x-ray diffraction, scanning electron microscopy, x-ray photoelectron spectroscopy and Raman spectroscopy

  17. Dose related anxiolytic effects of diazepam: relation with serum electrolytes, plasma osmolality and systolic blood pressure (sbp) in rats

    International Nuclear Information System (INIS)

    Farooq, R.; Haleem, D.J.; Haleem, M.A.

    2008-01-01

    Diazepam is an anxiolytic and anticonvulsant drug that also induces hypnosis. Changes in serum electrolyte balance, plasma osmolality and systolic blood pressure (SBP) are often associated with stress-induced anxiety. Administration of diazepam has been show to decrease stress-induced enhancement of hypothalamic pituitary adrenal cortical (HPA) axis. The present is designed to monitor the anxiolytic effects of different doses of diazepam (1 mg/kg, 2.5 mg/kg and 5 mg/kg) and its association with changes of serum electrolyte balance, plasma osmolality and SBP in rats. Administration of diazepam at doses of 1 mg/kg, 2.5 mg/kg and 5 mg/kg elicited anxiolytic effects monitored in light-dark transition test and increased serum concentration of electrolytes and plasma osmolality. Serum levels of magnesium as well as SBP decreased. The results are discussed in context of anxiolytic effects of diazepam to be mediated via a modulation of stress-induced increase in the activity of HPA-axis arid electrolytes balance. (author)

  18. Analyses of quenching process during turn-off of plasma electrolytic carburizing on carbon steel

    International Nuclear Information System (INIS)

    Wu, Jie; Liu, Run; Xue, Wenbin; Wang, Bin; Jin, Xiaoyue; Du, Jiancheng

    2014-01-01

    Highlights: • Cooling rate of carburized steel at the end of PEC treatment is measured. • The quench hardening in the fast or slow turn-off mode hardly takes place. • Decrease of the surface roughness during slow turn-off process is found. • A slow turn-off mode is recommended to replace the conventional turn-off mode. - Abstract: Plasma electrolytic carburizing (PEC) under different turn-off modes was employed to fabricate a hardening layer on carbon steel in glycerol solution without stirring at 380 V for 3 min. The quenching process in fast turn-off mode or slow turn-off mode of power supply was discussed. The temperature in the interior of steel and electron temperature in plasma discharge envelope during the quenching process were evaluated. It was found that the cooling rates of PEC samples in both turn-off modes were below 20 °C/s, because the vapor film boiling around the steel sample reduced the cooling rate greatly in terms of Leidenfrost effect. Thus the quench hardening hardly took place, though the slow turn-off mode slightly decreased the surface roughness of PEC steel. At the end of PEC treatment, the fast turn-off mode used widely at present cannot enhance the surface hardness by quench hardening, and the slow turn-off mode was recommended in order to protect the electronic devices against a large current surge

  19. Intermediate temperature solid oxide fuel cell based on lanthanum gallate electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Inagaki, Toru; Nishiwaki, Futoshi; Yamasaki, Satoru [The Kansai Electric Power Co. Inc., Energy Use R and D Center, 11-20 Nakoji 3-choume, Amagasaki, Hyogo 661-0974 (Japan); Akbay, Taner; Hosoi, Kei [Mitsubishi Materials Corporation, Corporate Technology and Development Division, 1002-14 Mukohyama, Naka, Ibaraki 311-0102 (Japan)

    2008-07-01

    The Kansai Electric Power Co. Inc. (KEPCO) and Mitsubishi Materials Corporation (MMC) have been developing intermediate temperature solid oxide fuel cells (IT-SOFCs) which are operable at a temperature range between 600 and 800 C. There are some significant features in IT-SOFC of KEPCO-MMC: (1) highly conductive lanthanum gallate-based oxide is adopted as an electrolyte to realize high-performance disk-type electrolyte-supported cells; (2) the cell-stacks with seal-less structure using metallic separators allow residual fuel to burn around the stack and the combustion heat is utilized for thermally self-sustainable operation; (3) the separators have flexible arms by which separate compressive forces can be applied for manifold parts and interconnection parts. We are currently participating in the project by New Energy and Industrial Technology Development Organization (NEDO) to develop 10 kW-class combined heat and power (CHP) systems. In FY2006, a 10 kW-class module was developed, with which the electrical efficiency of 50%HHV was obtained based on DC 12.6 kW. In the first quarter of FY2007, the 10 kW-class CHP system using the module gave the electrical efficiency of 41%HHV on AC 10 kW and the overall efficiency of 82%HHV when exhaust heat was recovered as 60 C hot water. Currently, the operation has been accumulated for about 2500 h to evaluate the long-term stability of the system. (author)

  20. Synthesis and characterization of novel electrolyte materials for intermediate temperature solid oxide fuel cells

    International Nuclear Information System (INIS)

    Chaubey, Nityanand; Chattopadhyaya, M.C.; Wani, B.N.; Bharadwaj, S.R.

    2008-01-01

    The high operating temperature of SOFCs using zirconia based electrolyte have several restrictions on materials used as interconnect and sealing and also requires use of expensive ceramics. Lowering the operating temperature of SOFCs to 600-800 deg C will enable to use cheaper materials and reduce the cost of fabrication while keeping the high power density. Lanthanide gallates are considered to be very promising solid electrolytes for intermediate temperature (600-800 deg C) solid oxide fuel cells (IT-SOFCs) due to their high ionic conductivity at lower temperatures. Phase purity of this material is a concern for the researchers for a long time. These materials are prepared at very high temperature (∼1400 deg C), since it is known that at around 1100 deg C, solubilities of Sr and Mg in LaGaO 3 were close to zero. Hence in the present work perovskite oxides of Ln 1-x Sr x Ga 1-y Mg y O 3-δ (Ln= Sm, Gd and x = 0.10, y=0.20) have been prepared by different methods i.e. solid state reaction, gel combustion and co-precipitation methods

  1. Exposure to automotive pollution increases plasma susceptibility to oxidation.

    Science.gov (United States)

    Sharman, James E; Coombes, Jeff S; Geraghty, Dominic P; Fraser, David I

    2002-01-01

    Low-density lipoprotein oxidation is implicated in the development of atherosclerosis. Plasma susceptibility to oxidation may be used as a marker of low-density lipoprotein oxidation and thus predict atherosclerotic risk. In this study the authors investigated the relationship between plasma susceptibility to oxidation and exposure to automotive pollution in a group of automobile mechanics (n = 16) exposed to high levels of automotive pollution, vs. matched controls (n = 13). The authors induced plasma oxidation by a free radical initiator and they determined susceptibility to oxidation by (1) change in absorbance at 234 nm, (2) lag time to conjugated diene formation, and (3) linear slope of the oxidation curve. Mechanics had significantly higher values (mean +/- standard error) for change in absorbance (1.60 +/- 0.05 vs. 1.36 +/- 0.05; p automotive pollutants increases plasma susceptibility to oxidation and may, in the long-term, increase the risk of developing atherosclerosis.

  2. Plasma and catalyst for the oxidation of NOx

    Science.gov (United States)

    Jõgi, Indrek; Erme, Kalev; Levoll, Erik; Raud, Jüri; Stamate, Eugen

    2018-03-01

    Efficient exhaust gas cleaning from NO x (NO and NO2) by absorption and adsorption based methods requires the oxidation of NO. The application of non-thermal plasma is considered as a promising oxidation method but the oxidation of NO by direct plasma remains limited due to the back-reaction of NO2 to NO mediated by O radicals in plasma. Indirect NO oxidation by plasma produced ozone allows to circumvent the back-reaction and further oxidize NO2 to N2O5 but the slow reaction rate for the latter process limits the efficiency of this process. Present paper gives an overview of the role of metal-oxide catalysts in the improvement of oxidation efficiency for both direct and indirect plasma oxidation of NO x . The plasma produced active oxygen species (O, O3) were shown to play an important role in the reactions taking place on the catalyst surfaces while the exact mechanism and extent of the effect were different for direct and indirect oxidation. In the case of direct plasma oxidation, both short and long lifetime oxygen species could reach the catalyst and participate in the oxidation of NO to NO2. The back-reaction in the plasma phase remained still important factor and limited the effect of catalyst. In the case of indirect oxidation, only ozone could reach the catalyst surface and improve the oxidation of NO2 to N2O5. The effect of catalyst at different experimental conditions was quantitatively described with the aid of simple global chemical kinetic models derived for the NO x oxidation either by plasma or ozone. The models allowed to compare the effect of different catalysts and to analyze the limitations for the efficiency improvement by catalyst.

  3. Study on electrolytic reduction with controlled oxygen flow for iron from molten oxide slag containing FeO

    Directory of Open Access Journals (Sweden)

    Gao Y.M.

    2013-01-01

    Full Text Available A ZrO2-based solid membrane electrolytic cell with controlled oxygen flow was constructed: graphite rod /[O]Fe+C saturated / ZrO2(MgO/(FeO slag/iron crucible. The feasibility of extraction of iron from molten oxide slag containing FeO at an applied voltage was investigated by means of the electrolytic cell. The effects of some important process factors on the FeO electrolytic reduction with the controlled oxygen flow were discussed. The results show that: solid iron can be extracted from molten oxide slag containing FeO at 1450ºC and an applied potential of 4V. These factors, such as precipitation and growth of solid iron dendrites, change of the cathode active area on the inner wall of the iron crucible and ion diffusion flux in the molten slag may affect the electrochemical reaction rate. The reduction for Fe2+ ions mainly appears on new iron dendrites of the iron crucible cathode, and a very small amount of iron are also formed on the MSZ (2.18% MgO partially stabilized zirconia tube/slag interface due to electronic conductance of MSZ tube. Internal electronic current through MSZ tube may change direction at earlier and later electrolytic reduction stage. It has a role of promoting electrolytic reduction for FeO in the molten slag at the earlier stage, but will lower the current efficiency at the later stage. The final reduction ratio of FeO in the molten slag can achieve 99%. A novel electrolytic method with controlled oxygen flow for iron from the molten oxide slag containing FeO was proposed. The theory of electrolytic reduction with the controlled oxygen flow was developed.

  4. High temperature mechanical properties of zirconia tapes used for electrolyte supported solid oxide fuel cells

    Science.gov (United States)

    Fleischhauer, Felix; Bermejo, Raul; Danzer, Robert; Mai, Andreas; Graule, Thomas; Kuebler, Jakob

    2015-01-01

    Solid-Oxide-Fuel-Cell systems are efficient devices to convert the chemical energy stored in fuels into electricity. The functionality of the cell is related to the structural integrity of the ceramic electrolyte, since its failure can lead to drastic performance losses. The mechanical property which is of most interest is the strength distribution at all relevant temperatures and how it is affected with time due to the environment. This study investigates the impact of the temperature on the strength and the fracture toughness of different zirconia electrolytes as well as the change of the elastic constants. 3YSZ and 6ScSZ materials are characterised regarding the influence of sub critical crack growth (SCCG) as one of the main lifetime limiting effects for ceramics at elevated temperatures. In addition, the reliability of different zirconia tapes is assessed with respect to temperature and SCCG. It was found that the strength is only influenced by temperature through the change in fracture toughness. SCCG has a large influence on the strength and the lifetime for intermediate temperature, while its impact becomes limited at temperatures higher than 650 °C. In this context the tetragonal 3YSZ and 6ScSZ behave quite different than the cubic 10Sc1CeSZ, so that at 850 °C it can be regarded as competitive compared to the tetragonal compounds.

  5. Significant Performance Enhancement in Asymmetric Supercapacitors based on Metal Oxides, Carbon nanotubes and Neutral Aqueous Electrolyte

    Science.gov (United States)

    Singh, Arvinder; Chandra, Amreesh

    2015-10-01

    Amongst the materials being investigated for supercapacitor electrodes, carbon based materials are most investigated. However, pure carbon materials suffer from inherent physical processes which limit the maximum specific energy and power that can be achieved in an energy storage device. Therefore, use of carbon-based composites with suitable nano-materials is attaining prominence. The synergistic effect between the pseudocapacitive nanomaterials (high specific energy) and carbon (high specific power) is expected to deliver the desired improvements. We report the fabrication of high capacitance asymmetric supercapacitor based on electrodes of composites of SnO2 and V2O5 with multiwall carbon nanotubes and neutral 0.5 M Li2SO4 aqueous electrolyte. The advantages of the fabricated asymmetric supercapacitors are compared with the results published in the literature. The widened operating voltage window is due to the higher over-potential of electrolyte decomposition and a large difference in the work functions of the used metal oxides. The charge balanced device returns the specific capacitance of ~198 F g-1 with corresponding specific energy of ~89 Wh kg-1 at 1 A g-1. The proposed composite systems have shown great potential in fabricating high performance supercapacitors.

  6. Reduced graphene oxide aerogel with high-rate supercapacitive performance in aqueous electrolytes

    Science.gov (United States)

    Si, Weijiang; Wu, Xiaozhong; Zhou, Jin; Guo, Feifei; Zhuo, Shuping; Cui, Hongyou; Xing, Wei

    2013-05-01

    Reduced graphene oxide aerogel (RGOA) is synthesized successfully through a simultaneous self-assembly and reduction process using hypophosphorous acid and I2 as reductant. Nitrogen sorption analysis shows that the Brunauer-Emmett-Teller surface area of RGOA could reach as high as 830 m2 g-1, which is the largest value ever reported for graphene-based aerogels obtained through the simultaneous self-assembly and reduction strategy. The as-prepared RGOA is characterized by a variety of means such as scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy. Electrochemical tests show that RGOA exhibits a high-rate supercapacitive performance in aqueous electrolytes. The specific capacitance of RGOA is calculated to be 211.8 and 278.6 F g-1 in KOH and H2SO4 electrolytes, respectively. The perfect supercapacitive performance of RGOA is ascribed to its three-dimensional structure and the existence of oxygen-containing groups.

  7. Demonstration of high efficiency intermediate-temperature solid oxide fuel cell based on lanthanum gallate electrolyte

    International Nuclear Information System (INIS)

    Inagaki, Toru; Nishiwaki, Futoshi; Kanou, Jirou; Yamasaki, Satoru; Hosoi, Kei; Miyazawa, Takashi; Yamada, Masaharu; Komada, Norikazu

    2006-01-01

    The Kansai Electric Power Co., Inc. (KEPCO) and Mitsubishi Materials Corporation (MMC) have been jointly developing intermediate-temperature solid oxide fuel cells (SOFCs). The operation temperatures between 600 and 800 o C were set as the target, which enable SOFC to use less expensive metallic separators for cell-stacking and to carry out internal reforming of hydrocarbon fuels. The electrolyte-supported planar-type cells were fabricated using highly conductive lanthanum gallate-based electrolyte, La(Sr)Ga(Mg,Co)O 3-δ , Ni-(CeO 2 ) 1-x (SmO 1.5 ) x cermet anode, and Sm(Sr)CoO 3-δ cathode. The 1 kW-class power generation modules were fabricated using a seal-less stack of the cells and metallic separators. The 1 kW-class prototype power generation system with the module was developed with the high performance cell, which showed the thermally self-sustainability. The system included an SOFC module, a dc-ac inverter, a desulfurizer, and a heat recovery unit. It provided stable ac power output of 1 kW with the electrical efficiency of 45% LHV based on ac output by using city gas as a fuel, which was considered to be excellent for such a small power generation system. And the hot water of 90 o C was obtained using high temperature off-gas from SOFC

  8. Demonstration of high efficiency intermediate-temperature solid oxide fuel cell based on lanthanum gallate electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Inagaki, Toru [Kansai Electric Power Co. Inc., Energy Use R and D Center, 11-20 Nakoji 3-chome, Amagasaki, Hyogo 661-0974 (Japan)]. E-mail: inagaki@rdd.kepco.co.jp; Nishiwaki, Futoshi [Kansai Electric Power Co. Inc., Energy Use R and D Center, 11-20 Nakoji 3-chome, Amagasaki, Hyogo 661-0974 (Japan); Kanou, Jirou [Kansai Electric Power Co. Inc., Energy Use R and D Center, 11-20 Nakoji 3-chome, Amagasaki, Hyogo 661-0974 (Japan); Yamasaki, Satoru [Kansai Electric Power Co. Inc., Energy Use R and D Center, 11-20 Nakoji 3-chome, Amagasaki, Hyogo 661-0974 (Japan); Hosoi, Kei [Mitsubishi Materials Corporation, Central Research Institute, 1002-14 Mukohyama, Naka-machi, Naka-gun, Ibaraki 311-0102 (Japan); Miyazawa, Takashi [Mitsubishi Materials Corporation, Central Research Institute, 1002-14 Mukohyama, Naka-machi, Naka-gun, Ibaraki 311-0102 (Japan); Yamada, Masaharu [Mitsubishi Materials Corporation, Central Research Institute, 1002-14 Mukohyama, Naka-machi, Naka-gun, Ibaraki 311-0102 (Japan); Komada, Norikazu [Mitsubishi Materials Corporation, Central Research Institute, 1002-14 Mukohyama, Naka-machi, Naka-gun, Ibaraki 311-0102 (Japan)

    2006-02-09

    The Kansai Electric Power Co., Inc. (KEPCO) and Mitsubishi Materials Corporation (MMC) have been jointly developing intermediate-temperature solid oxide fuel cells (SOFCs). The operation temperatures between 600 and 800 {sup o}C were set as the target, which enable SOFC to use less expensive metallic separators for cell-stacking and to carry out internal reforming of hydrocarbon fuels. The electrolyte-supported planar-type cells were fabricated using highly conductive lanthanum gallate-based electrolyte, La(Sr)Ga(Mg,Co)O{sub 3-{delta}}, Ni-(CeO{sub 2}){sub 1-x}(SmO{sub 1.5}) {sub x} cermet anode, and Sm(Sr)CoO{sub 3-{delta}} cathode. The 1 kW-class power generation modules were fabricated using a seal-less stack of the cells and metallic separators. The 1 kW-class prototype power generation system with the module was developed with the high performance cell, which showed the thermally self-sustainability. The system included an SOFC module, a dc-ac inverter, a desulfurizer, and a heat recovery unit. It provided stable ac power output of 1 kW with the electrical efficiency of 45% LHV based on ac output by using city gas as a fuel, which was considered to be excellent for such a small power generation system. And the hot water of 90 {sup o}C was obtained using high temperature off-gas from SOFC.

  9. Long-term Steam Electrolysis with Electrolyte-Supported Solid Oxide Cells

    International Nuclear Information System (INIS)

    Schefold, Josef; Brisse, Annabelle; Poepke, Hendrik

    2015-01-01

    Steam electrolysis over 11000 h with an electrolyte-supported solid oxide cell is discussed. The cell of 45 cm"2 area consists of a scandia/ceria doped zirconia electrolyte (6Sc1CeSZ), CGO diffusion-barrier/adhesion layers, a lanthanum strontium cobaltite ferrite (LSCF) oxygen electrode, and a nickel steam/hydrogen electrode. After initial 2500 h operation with lower current-density magnitude, the current density was set to j = -0.9 A cm"−"2 and the steam conversion rate to 51%. This led to a cell voltage of 1.185 V at 847 °C cell temperature. Average voltage degradation was 7.3 mV/1000 h ( 100% throughout the test (with an external heat source for evaporation). Impedance spectroscopic measurements revealed a degradation almost entirely due to increasing ohmic resistance. The rate of resistance increase was initially faster (up to 40 mΩ cm"2/1000 h) and stabilised after several 1000 h operation. After 9000 h a small (non-ohmic) electrode degradation became detectable (<2 mV/1000 h), superimposed to ohmic degradation. The small electrode degradation is understood as indication for largely reversible (electrolysis cell/fuel cell) behaviour.

  10. Criticality safety analysis for plutonium dissolver using silver mediated electrolytic oxidation method

    International Nuclear Information System (INIS)

    Umeda, Miki; Sugikawa, Susumu; Nakamura, Kazuhito; Egashira, Tetsurou

    1998-08-01

    Design and construction of a plutonium dissolver using silver mediated electrolytic oxidation method are promoted in NUCEF. Criticality safety analysis for the plutonium dissolver is described in this report. The electrolytic plutonium dissolver consists of connection pipes and three pots for MOX powder supply, circulation and electrolysis. The criticality control for the dissolver is made by geometrically safe shape with mass limitation. Monte Carlo code KENO-IV using MGCL-137 library based on ENDF/B-IV was used for the criticality safety analysis for the plutonium dissolver. Considering the required size for construction and criticality safety, diameter of pot and distance between two pots were determined. On this condition, the criticality safety analysis for the plutonium dissolver with connection pipes was carried out. As the result of the criticality safety analysis, an effective neutron multiplication factor keff of 0.91 was obtained and the criticality safety of the plutonium dissolver was confirmed on the basis of criteria of ≤0.95. (author)

  11. Proton conducting sodium alginate electrolyte laterally coupled low-voltage oxide-based transistors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yang Hui; Wan, Qing, E-mail: wanqing@nju.edu.cn [Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); Qiang Zhu, Li, E-mail: lqzhu@nimte.ac.cn [Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Shi, Yi [School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China)

    2014-03-31

    Solution-processed sodium alginate electrolyte film shows a high proton conductivity of ∼5.5 × 10{sup −3} S/cm and a high lateral electric-double-layer (EDL) capacitance of ∼2.0 μF/cm{sup 2} at room temperature with a relative humidity of 57%. Low-voltage in-plane-gate indium-zinc-oxide-based EDL transistors laterally gated by sodium alginate electrolytes are fabricated on glass substrates. The field-effect mobility, current ON/OFF ratio, and subthreshold swing of such EDL transistors are estimated to be 4.2 cm{sup 2} V{sup −1} s{sup −1}, 2.8 × 10{sup 6}, and 130 mV/decade, respectively. At last, a low-voltage driven resistor-load inverter is also demonstrated. Such in-plane-gate EDL transistors have potential applications in portable electronics and low-cost biosensors.

  12. Synthesis of electro-active manganese oxide thin films by plasma enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Merritt, Anna R. [Energetics Research Division, Naval Air Warfare Center Weapons Division, China Lake, CA 93555 (United States); Rajagopalan, Ramakrishnan [Department of Engineering, The Pennsylvania State University, Dubois, PA 15801 (United States); Materials Research Institute, The Pennsylvania State University, University Park, PA 16802 (United States); Carter, Joshua D. [Energetics Research Division, Naval Air Warfare Center Weapons Division, China Lake, CA 93555 (United States)

    2014-04-01

    The good stability, cyclability and high specific capacitance of manganese oxide (MnO{sub x}) has recently promoted a growing interest in utilizing MnO{sub x} in asymmetric supercapacitor electrodes. Several literature reports have indicated that thin film geometries of MnO{sub x} provide specific capacitances that are much higher than bulk MnO{sub x} powders. Plasma enhanced chemical vapor deposition (PECVD) is a versatile technique for the production of metal oxide thin films with high purity and controllable thickness. In this work, MnO{sub x} thin films deposited by PECVD from a methylcyclopentadienyl manganese tricarbonyl precursor are presented and the effect of processing conditions on the quality of MnO{sub x} films is described. The film purity and oxidation state of the MnO{sub x} films were studied by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Preliminary electrochemical testing of MnO{sub x} films deposited on carbon fiber electrodes in aqueous electrolytes indicates that the PECVD synthesized films are electrochemically active. - Highlights: • Plasma enhanced chemical vapor deposition of manganese oxide thin films. • Higher plasma power and chamber pressure increase deposition rate. • Manganese oxide thin films are electrochemically active. • Best electrochemical performance observed for pure film with low stress • Lower capacitance observed at higher scan rates despite thin film geometry.

  13. Performance enhancement of membrane electrode assemblies with plasma etched polymer electrolyte membrane in PEM fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yong-Hun; Yoon, Won-Sub [School of Advanced Materials Engineering, Kookmin University, 861-1 Jeongneung-dong, Seongbuk-gu, Seoul 136-702 (Korea); Bae, Jin Woo; Cho, Yoon-Hwan; Lim, Ju Wan; Ahn, Minjeh; Jho, Jae Young; Sung, Yung-Eun [World Class University (WCU) program of Chemical Convergence for Energy and Environment (C2E2), School of Chemical and Biological Engineering, College of Engineering, Seoul National University (SNU), 599 Gwanak-Ro, Gwanak-gu, Seoul 151-744 (Korea); Kwon, Nak-Hyun [Fuel Cell Vehicle Team 3, Advanced Technology Center, Corporate Research and Development Division, Hyundai-Kia Motors, 104 Mabuk-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-912 (Korea)

    2010-10-15

    In this work, a surface modified Nafion 212 membrane was fabricated by plasma etching in order to enhance the performance of a membrane electrode assembly (MEA) in a polymer electrolyte membrane fuel cell. Single-cell performance of MEA at 0.7 V was increased by about 19% with membrane that was etched for 10 min compared to that with untreated Nafion 212 membrane. The MEA with membrane etched for 20 min exhibited a current density of 1700 mA cm{sup -2} at 0.35 V, which was 8% higher than that of MEA with untreated membrane (1580 mA cm{sup -2}). The performances of MEAs containing etched membranes were affected by complex factors such as the thickness and surface morphology of the membrane related to etching time. The structural changes and electrochemical properties of the MEAs with etched membranes were characterized by field emission scanning electron microscopy, Fourier transform-infrared spectrometry, electrochemical impedance spectroscopy, and cyclic voltammetry. (author)

  14. Deposition of waste kaolin in aluminum alloy by electrolytic plasma technique

    International Nuclear Information System (INIS)

    Palinkas, Fabiola Bergamasco da Silva Marcondes; Antunes, Maria Lucia Pereira; Cruz, Nilson Cristino; Rangel, Elidiane Cipriano; Souza, Jose Antonio da Silva

    2016-01-01

    Full text: Kaolin is a widely explored mineral for various industrial purposes and its processing generates up to 90% of waste, corresponding to 500 thousand tons annually. The Deposition of Kaolin residue on aluminum alloys by electrolytic plasma has objective of a valorization of the residue. It was evaluated the mineralogical composition by X-ray diffraction (XRD), using PANalytical diffractometer X'Pert Pro. The scanning electron microscopy (SEM) and the spectrometry of dispersive of energy (EDS) evaluated the morphology and elementary chemical composition by microscope scanning electron JEOL JSM-6010LA. The Infrared Spectroscopy (FTIR) has used a Spectrometer the Perkin-Elmer 1760X FT-IR with spectral range 4000-400 cm -1 . XRD results indicate peaks of kaolinite as the main constituent. The morphology of the particles correspond to pseudo-hexagonal lamellar crystals characteristic of kaolinite, analysis by EDS allows to identify the composition of the particles as Al and Si. The samples were deposited at concentrations of 5, 10 and 15 mg of the residue and each concentration were considered deposition times of 5, 10 and 15 minutes. Tests evaluate the films as the wettability, chemical composition, morphology, mechanical strength and corrosion resistance. Results indicate the presence of kaolinite, alumina and mullite in the obtained coatings. (author)

  15. Tris(trimethylsilyl)phosphate as electrolyte additive for self-discharge suppression of layered nickel cobalt manganese oxide

    International Nuclear Information System (INIS)

    Liao, Xiaolin; Zheng, Xiongwen; Chen, Jiawei; Huang, Ziyu; Xu, Mengqing; Xing, Lidan; Liao, Youhao; Lu, Qilun; Li, Xiangfeng; Li, Weishan

    2016-01-01

    Highlights: • TMSP is effective for self-discharge suppression of the charged NCM under 4.5 V. • TMSP oxidizes preferentially forming protective cathode interface film on NCM. • The film suppresses electrolyte decomposition and prevents NCM destruction. - Abstract: Application of layered nickel cobalt manganese oxide as cathode under higher potential than conventional 4.2 V yields a significant improvement in energy density of lithium ion battery. However, the cathode fully charged under high potential suffers serious self-discharge, in which the interaction between the cathode and electrolyte proceeds without potential limitation. In this work, we use tris(trimethylsilyl)phosphate (TMSP) as an electrolyte additive to solve this problem. A representative layered nickel cobalt manganese oxide, LiNi 1/3 Co 1/3 Mn 1/3 O 2 , is considered. The effect of TMSP on self-discharge behavior of LiNi 1/3 Co 1/3 Mn 1/3 O 2 is evaluated by physical and electrochemical methods. It is found that the self-discharge of charged LiNi 1/3 Co 1/3 Mn 1/3 O 2 can be suppressed significantly by using TMSP. TMSP is oxidized preferentially in comparison with the standard electrolyte during initial charging process forming a protective cathode interface film, which avoids the interaction between cathode and electrolyte at any potential and thus prevents electrolyte decomposition and protects LiNi 1/3 Co 1/3 Mn 1/3 O 2 from structure destruction.

  16. Effects of Silica Nanostructures in Poly(ethylene oxide)-Based Composite Polymer Electrolytes.

    Science.gov (United States)

    Mohanta, Jagdeep; Anwar, Shahid; Si, Satyabrata

    2016-06-01

    The present work describes the synthesis of some poly(ethylene oxide)-based nanocomposite polymer electrolyte films using various silica nanostructures as the inorganic filler by simple solution mixing technique, in which the nature of the silica nanostructures play a vital role in modulating their electrochemical performances at room temperature. The silica nanostructures are prepared by ammonical hydrolysis of tetraethyl orthosilicate following the modified St6ber method. The resulting films are characterized by X-ray diffraction and differential scanning calorimeter to study their crystallinity. Room temperature AC impedance spectroscopy is utilized to determine the Li+ ion conductivity of the resulting films. The observed conductivity values of various NCPE films depend on the nature of silica filling as well as on their surface characteristics and also on the varying PEO-Li+ ratio, which is observed to be in the order of 10(-7)-10(-6) S cm(-1).

  17. Optimization of spin-coated electrodes for electrolyte-supported solid oxide fuel cells

    International Nuclear Information System (INIS)

    Nobrega, Shayenne Diniz da; Monteiro, Natalia Kondo; Tabuti, Francisco; Fonseca, Fabio Coral; Florio, Daniel Zanetti de

    2017-01-01

    Electrodes for electrolyte-supported solid oxide fuel cells (SOFC’s) were fabricated by spin coating. Strontium-doped lanthanum manganite (LSM) cathode and nickel yttria-stabilized zirconia cermet anodes were synthesized and processed for enhanced deposition conditions. The influence of electrode microstructural parameters was investigated by a systematic experimental procedure aiming at optimized electrochemical performance of single cells. Polarization curves showed a strong dependence on both electrode thickness and sintering temperature. By a systematic control of such parameters, the performance of single cells was significantly enhanced due to decreasing of polarization resistance from 26 Ω cm² to 0.6 Ω cm² at 800°C. The results showed that spin-coated electrodes can be optimized for fast and cost effective fabrication of SOFCs. (author)

  18. Proton Conducting Graphene Oxide/Chitosan Composite Electrolytes as Gate Dielectrics for New-Concept Devices.

    Science.gov (United States)

    Feng, Ping; Du, Peifu; Wan, Changjin; Shi, Yi; Wan, Qing

    2016-09-30

    New-concept devices featuring the characteristics of ultralow operation voltages and low fabrication cost have received increasing attention recently because they can supplement traditional Si-based electronics. Also, organic/inorganic composite systems can offer an attractive strategy to combine the merits of organic and inorganic materials into promising electronic devices. In this report, solution-processed graphene oxide/chitosan composite film was found to be an excellent proton conducting electrolyte with a high specific capacitance of ~3.2 μF/cm 2 at 1.0 Hz, and it was used to fabricate multi-gate electric double layer transistors. Dual-gate AND logic operation and two-terminal diode operation were realized in a single device. A two-terminal synaptic device was proposed, and some important synaptic behaviors were emulated, which is interesting for neuromorphic systems.

  19. Nanostructured Gd-CeO2 electrolyte for solid oxide fuel cell by aqueous tape casting

    Science.gov (United States)

    Akbari-Fakhrabadi, A.; Mangalaraja, R. V.; Sanhueza, Felipe A.; Avila, Ricardo E.; Ananthakumar, S.; Chan, S. H.

    2012-11-01

    Gadolinia-doped ceria (Ce0.9Gd0.1O1.95, GDC) electrolyte was fabricated by aqueous-based tape casting method for solid oxide fuel cells (SOFCs). The ceramic powder prepared by combustion synthesis was used with poly acrylic acid (PAA), poly vinyl alcohol (PVA), poly ethylene glycol (PEG), Octanol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol ethoxylate and double distilled water as dispersant, binder, plasticizer, defoamer, surfactant and solvent respectively, to prepare stable GDC slurry. The conditions for preparing stable GDC slurries were studied and optimized by sedimentation, zeta potential and viscosity measurements. Green tapes with smooth surface, flexibility, thickness in the range of 0.35-0.4 mm and 45% relative green density were prepared. Conventional and flash sintering techniques were used and compared for densification which demonstrated the possibility of surpassing sintering at high temperatures and retarding related grain growth.

  20. Optimization of spin-coated electrodes for electrolyte-supported solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Nobrega, Shayenne Diniz da; Monteiro, Natalia Kondo; Tabuti, Francisco; Fonseca, Fabio Coral, E-mail: shaynnedn@hotmail.com, E-mail: nataliakm@usp.br, E-mail: fntabuti@ipen.br, E-mail: fabiocf@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil); Florio, Daniel Zanetti de, E-mail: daniel.florio@ufabc.edu.br [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil)

    2017-01-15

    Electrodes for electrolyte-supported solid oxide fuel cells (SOFC’s) were fabricated by spin coating. Strontium-doped lanthanum manganite (LSM) cathode and nickel yttria-stabilized zirconia cermet anodes were synthesized and processed for enhanced deposition conditions. The influence of electrode microstructural parameters was investigated by a systematic experimental procedure aiming at optimized electrochemical performance of single cells. Polarization curves showed a strong dependence on both electrode thickness and sintering temperature. By a systematic control of such parameters, the performance of single cells was significantly enhanced due to decreasing of polarization resistance from 26 Ω cm² to 0.6 Ω cm² at 800°C. The results showed that spin-coated electrodes can be optimized for fast and cost effective fabrication of SOFCs. (author)

  1. Rotating disk electrode study of borohydride oxidation in a molten eutectic electrolyte and advancements in the intermediate temperature borohydride battery

    Science.gov (United States)

    Wang, Andrew; Gyenge, Előd L.

    2017-08-01

    The electrode kinetics of the NaBH4 oxidation reaction (BOR) in a molten NaOH-KOH eutectic mixture is investigated by rotating disk electrode (RDE) voltammetry on electrochemically oxidized Ni at temperatures between 458 K and 503 K. The BH4- diffusion coefficient in the molten alkali eutectic together with the BOR activation energy, exchange current density, transfer coefficient and number of electrons exchanged, are determined. Electrochemically oxidized Ni shows excellent BOR electrocatalytic activity with a maximum of seven electrons exchanged and a transfer coefficient up to one. X-ray photoelectron spectroscopy (XPS) reveals the formation of NiO as the catalytically active species. The high faradaic efficiency and BOR rate on oxidized Ni anode in the molten electrolyte compared to aqueous alkaline electrolytes is advantageous for power sources. A novel molten electrolyte battery design is investigated using dissolved NaBH4 at the anode and immobilized KIO4 at the cathode. This battery produces a stable open-circuit cell potential of 1.04 V, and a peak power density of 130 mW cm-2 corresponding to a superficial current density of 160 mA cm-2 at 458 K. With further improvements and scale-up borohydride molten electrolyte batteries and fuel cells could be integrated with thermal energy storage systems.

  2. Using Dark Field X-Ray Microscopy To Study In-Operando Yttria Stabilized Zirconia Electrolyte Supported Solid Oxide Cell

    DEFF Research Database (Denmark)

    Sierra, J. X.; Poulsen, H. F.; Jørgensen, P. S.

    Dark Field X-Ray Microscopy is a promising technique to study the structure of materials in nanometer length scale. In combination with x-ray diffraction technique, the microstructure evolution of Yttria Stabilized Zirconia electrolyte based solid oxide cell was studied running at extreme operating...

  3. Intermediate temperature solid oxide fuel cell based on lanthanum gallate electrolyte

    Science.gov (United States)

    Inagaki, Toru; Nishiwaki, Futoshi; Yamasaki, Satoru; Akbay, Taner; Hosoi, Kei

    The Kansai Electric Power Co. Inc. (KEPCO) and Mitsubishi Materials Corporation (MMC) have been developing intermediate temperature solid oxide fuel cells (IT-SOFCs) which are operable at a temperature range between 600 and 800 °C. There are some significant features in IT-SOFC of KEPCO-MMC: (1) highly conductive lanthanum gallate-based oxide is adopted as an electrolyte to realize high-performance disk-type electrolyte-supported cells; (2) the cell-stacks with seal-less structure using metallic separators allow residual fuel to burn around the stack and the combustion heat is utilized for thermally self-sustainable operation; (3) the separators have flexible arms by which separate compressive forces can be applied for manifold parts and interconnection parts. We are currently participating in the project by New Energy and Industrial Technology Development Organization (NEDO) to develop 10 kW-class combined heat and power (CHP) systems. In FY2006, a 10 kW-class module was developed, with which the electrical efficiency of 50%HHV was obtained based on DC 12.6 kW. In the first quarter of FY2007, the 10 kW-class CHP system using the module gave the electrical efficiency of 41%HHV on AC 10 kW and the overall efficiency of 82%HHV when exhaust heat was recovered as 60 °C hot water. Currently, the operation has been accumulated for about 2500 h to evaluate the long-term stability of the system.

  4. Basic study on decontamination of TRU wastes with cerium mediated electrolytic oxidation method

    International Nuclear Information System (INIS)

    Ishii, Junichi; Kobayashi, Fuyumi; Uchida, Shoji; Sumiya, Masato; Kida, Takashi; Shirahashi, Koichi; Umeda, Miki; Sakuraba, Koichi

    2010-03-01

    At Nuclear Fuel Cycle Safety Engineering Research Facility (NUCEF), the cerium mediated electrolytic oxidation method which is a decontamination technique to decrease the radioactivity of TRU wastes to the clearance-level has been developed for the effective reduction of TRU wastes generated from the decommissioning of a nuclear fuel reprocessing facility and so on. This method corrodes the oxide layer and the surface of metallic TRU metal wastes by the strong oxidation power of Ce 4+ in nitric acid. In this study, parameter tests were conducted to optimize the solution condition of Ce 3+ initial concentrations and nitric acid concentrations. The target corrosion rate of metallic TRU wastes set to be 2 - 4 μm/h for the practical use of this method. Under the optimized solution condition, a dissolution test of stainless steel simulating wastes was carried out. From the result of the dissolution test, the average corrosion rate was 3.3 μm/h during the test time of 90 hours. Based on the supposition that the corrosion depth of metallic TRU wastes was 20 μm enough to achieve the clearance-level, the treatment time for the decontamination was about 6 hours. It was confirmed from the result that the decontamination could be performed within one day and the decontamination solution could repeatedly reuse 15 times. (author)

  5. Growth behavior of anodic oxide formed by aluminum anodizing in glutaric and its derivative acid electrolytes

    Science.gov (United States)

    Nakajima, Daiki; Kikuchi, Tatsuya; Natsui, Shungo; Suzuki, Ryosuke O.

    2014-12-01

    The growth behavior of anodic oxide films formed via anodizing in glutaric and its derivative acid solutions was investigated based on the acid dissociation constants of electrolytes. High-purity aluminum foils were anodized in glutaric, ketoglutaric, and acetonedicarboxylic acid solutions under various electrochemical conditions. A thin barrier anodic oxide film grew uniformly on the aluminum substrate by glutaric acid anodizing, and further anodizing caused the film to breakdown due to a high electric field. In contrast, an anodic porous alumina film with a submicrometer-scale cell diameter was successfully formed by ketoglutaric acid anodizing at 293 K. However, the increase and decrease in the temperature of the ketoglutaric acid resulted in non-uniform oxide growth and localized pitting corrosion of the aluminum substrate. An anodic porous alumina film could also be fabricated by acetonedicarboxylic acid anodizing due to the relatively low dissociation constants associated with the acid. Acid dissociation constants are an important factor for the fabrication of anodic porous alumina films.

  6. The rheology of oxide dispersions and the role of concentrated electrolyte solutions

    International Nuclear Information System (INIS)

    Biggs, Simon; Tindley, Amy

    2007-01-01

    Stability control of particulate dispersions is critical to a wide range of industrial processes. In the UK nuclear industry, significant volumes of waste materials arising from the corrosion products of Magnox fuel rods currently require treatment and storage. The majority of this waste is present as aqueous dispersions of oxide particulates. Treatment of these dispersions will require a variety of unit operations including mobilisation, transport and solid- liquid separation. Typically these processes must operate across a narrow optimal range of pH and the dispersions are, almost without exception, found in complex electrolyte conditions of high overall concentration. Knowledge of the behaviour of oxides in various electrolyte conditions and over a large pH range is essential for the efficient design and control of any waste processing approach. The transport properties of particle dispersions are characterised by the rheological properties. It is well known that particle dispersion rheology is strongly influenced by particle-particle interaction forces, and that particle-particle interactions are strongly influenced by adsorbed ions on the particle surfaces. Here we correlate measurements of the shear yield stress and the particle zeta potentials to provide insight as to the role of ions in moderating particle interactions. The zeta potential of model TiO 2 suspensions were determined (Colloidal Dynamics Zeta Probe) over a range of pH for a series of alkali metal halides and quaternary ammonium halides at a range of solution concentrations (0.001 M - 1 M). The results show some surprising co-ion effects at high electrolyte concentrations (>0.5 M) and indicate that even ions generally considered to be indifferent induce a shift in iso-electric point (i.e.p.) which is inferred as being due to specific adsorption of ions. The shear yield stress values of concentrated titania dispersions were measured using a Bohlin C-VOR stress controlled rheometer. The shear

  7. Influence of Electrolyte Composition on the Calcium-Phosphorus compound Coating on Titanium Substrate by Micro-arc Oxidation

    Institute of Scientific and Technical Information of China (English)

    ZHU Xiu-hong; WANG Cong-zeng; KOU Bin-da; SU Xue-kuan; ZHANG Wen-quan

    2004-01-01

    The compound bioceramic coating containing calcium (Ca) and phosphorus (P) on titanium alloy substrate was prepared by means of micro-arc oxidation (MAO) treatment. The results show that under the different electrolyte the coating with the color of gray or black and surface morphology of cauliflower or honeycomb, where Ca content and P contain can attain 30% and 20% respectively, can be obtained. Meanwhile, the influences of electrolyte temperature, current density and discharge time on morphology and thickness of coating are also discussed here.

  8. Production of uranium metal via electrolytic reduction of uranium oxide in molten LiCl and salt distillation

    International Nuclear Information System (INIS)

    Eun-Young Choi; Chan Yeon Won; Dae-Seung Kang; Sung-Wook Kim; Ju-Sun Cha; Sung-Jai Lee; Wooshin Park; Hun Suk Im; Jin-Mok Hur

    2015-01-01

    Recovery of metallic uranium has been achieved by electrolytic reduction of uranium oxide in a molten LiCl-Li 2 O electrolyte at 650 deg C, followed by the removal of the residual salt by vacuum distillation at 850 deg C. Four types of stainless steel mesh baskets, with various mesh sizes (325, 1,400 and 2,300 meshes) and either three or five ply layers, were used both as cathodes and to contain the reduced product in the distillation stage. The recovered uranium had a metal fraction greater than 98.8 % and contained no residual salt. (author)

  9. Application of oxide coatings to metals in electrolyte solutions by microplasma methods

    Directory of Open Access Journals (Sweden)

    Vladimirovich Timoshenko, Aleksander

    2000-10-01

    Full Text Available Microplasma oxidation of aluminium alloys in alkaline colloidal and finely dispersed solutions is analysed. Oxidation causes both electrolyte and alloy components to be incorporated into resultant coatings, which affect the deposition parameters and coating properties. Oxidation process has been studied at spark, micro-are, and are stages under an alternating current polarisation and under purely anodic polarisation. It is shown that the cathodic component of the alternating current not only facilitates subsequent anodic process, but also contributes to the formation of an oxide layer.

    Se ha examinado la aplicación de procesos de oxidación por microplasma de las aleaciones de aluminio en electrólitos alcalinos, tanto en estado coloidal como microdisperso. Se descubrió que durante el proceso de la oxidación, en la estructura del recubrimiento óxido, van incluyéndose tanto los componentes del electrólito como los de la aleación, lo que modifica las propiedades y parámetros de deposición de las aleaciones obtenidas. El proceso de la oxidación se examinó a lo largo de las siguientes etapas: chispas, micro-arco y arco, tanto bajo la polarización de la corriente alterna como en condiciones de polarización anódica. Se ha demostrado que la componente catódica de la corriente alterna polarizante no sólo facilita los siguientes procesos anódicos, sino que además contribuye a los procesos de formación de la capa óxida.

  10. Synthesis and ceramic processing of zirconia alumina composites for application as solid oxide fuel cell electrolytes

    International Nuclear Information System (INIS)

    Garcia, Rafael Henrique Lazzari

    2007-01-01

    The global warmness and the necessity to obtain clean energy from alternative methods than petroleum raises the importance of developing cleaner and more efficient systems of energy generation, among then, the solid oxide fuel cell (SOFC). Cubic stabilized zirconia (CSZ) has been the most studied material as electrolyte in SOFC, due to its ionic conductivity and great stability at operation conditions. However, its low fracture toughness difficulties its application as a thin layer, what could lead to an improvement of cell efficiency. In this sense, the alumina addition in CSZ forms a composite, which can shift its mechanical properties, without compromising its electrical properties. In this work, coprecipitation synthesis route and ceramic processing of zirconia-alumina composites were studied, in order to establish optimum conditions to attain high density, homogeneous microstructure, and better mechanical properties than CSZ, without compromising ionic conductivity. For this purpose, composites containing up to 40 wt % of alumina, in a 9 mol % yttria-stabilized zirconia (9Y-CSZ) matrix were evaluated. In order to optimize the synthesis of the composites, a preliminary study of powder obtaining and processing were carried out, at compositions containing 20 wt % of alumina, in 9Y-CSZ. The ceramic powders were characterized by helium picnometry, X-ray diffraction, scanning electronic microscopy, transmission electronic microscopy, thermogravimetry, differential scanning calorimetry, granulometry by laser diffraction and gas adsorption (BET). The characterization of sinterized compacts were performed by X-ray diffraction, scanning electron microscopy, optical microscopy, density measurements, Vickers indentation and impedance spectroscopy. The obtained results show that the alumina addition, in the 9Y-CSZ matrix powders, raises the specific surface area, promotes deagglomeration of powders and elevates the oxides crystallization temperature, requiring higher

  11. Selective deposition of nanostructured ruthenium oxide using Tobacco mosaic virus for micro-supercapacitors in solid Nafion electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Gnerlich, Markus; Ben-Yoav, Hadar; Culver, James N.; Ketchum, Douglas R.; Ghodssi, Reza

    2015-10-01

    A three-dimensional micro-supercapacitor has been developed using a novel bottom-up assembly method combining genetically modified Tobacco mosaic virus (TMV-1Cys), photolithographically defined micropillars and selective deposition of ruthenium oxide on multi-metallic microelectrodes. The three-dimensional microelectrodes consist of a titanium nitride current collector with two functionalized areas: (1) gold coating on the active electrode area promotes TMV-1Cys adhesion, and (2) sacrificial nickel pads dissolve in ruthenium tetroxide plating solution to produce ruthenium oxide on all electrically connected areas. The microfabricated electrodes are arranged in an interdigitated pattern, and the capacitance per electrode has been measured as high as 203 mF cm-2 with solid Nafion electrolyte. The process integration of bio-templated ruthenium oxide with microfabricated electrodes and solid electrolyte is an important advance towards the energy storage needs of mass produced self-sufficient micro-devices.

  12. Synthesis of polymer electrolyte membranes from cellulose acetate/poly(ethylene oxide)/LiClO{sub 4} for lithium ion battery application

    Energy Technology Data Exchange (ETDEWEB)

    Nurhadini,, E-mail: nur-chem@yahoo.co.id; Arcana, I Made, E-mail: arcana@chem.itb.ac.id [Inorganic and Physical Chemistry Research Division, Faculty of Mathematics and Natural Sciences, Institiut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132 (Indonesia)

    2015-09-30

    This study was conducted to determine the effect of cellulose acetate on poly(ethylene oxide)-LiClO{sub 4} membranes as the polymer electrolyte. Cellulose acetate is used as an additive to increase ionic conductivity and mechanical property of polymer electrolyte membranes. The increase the percentage of cellulose acetate in membranes do not directly effect on the ionic conductivity, and the highest ionic conductivity of membranes about 5,7 × 10{sup −4} S/cm was observed in SA/PEO/LiClO{sub 4} membrane with cellulose ratio of 10-25% (w/w). Cellulose acetate in membranes increases mechanical strength of polymer electrolyte membranes. Based on TGA analysis, this polymer electrolyte thermally is stable until 270 °C. The polymer electrolyte membrane prepared by blending the cellulose acetate, poly(ethylene oxide), and lithium chlorate could be potentially used as a polymer electrolyte for lithium ion battery application.

  13. Electrolyte bi-layering strategy to improve the performance of an intermediate temperature solid oxide fuel cell: A review

    Science.gov (United States)

    Shri Prakash, B.; Pavitra, R.; Senthil Kumar, S.; Aruna, S. T.

    2018-03-01

    Lowering of operation temperature has become one of the primary goals of solid oxide fuel (SOFC) research as reduced temperature improves the prospects for widespread commercialization of this energy system. Reduced operational temperature also mitigates the issues associated with high temperature SOFCs and paves way not only for the large scale stationary power generation but also makes SOFCs viable for portable and transport applications. However, there are issues with electrolyte and cathode materials at low temperatures, individually as well as in association with other components, which makes the performance of the SOFCs less satisfactory than expected at lowered temperatures. Bi-layering of electrolytes and impregnation of cathodes have emerged as two important strategies to overcome these issues and achieve higher performance at low temperatures. This review article provides the perspective on the strategy of bi-layering of electrolyte to achieve the desired high performance from SOFC at low to intermediate temperatures.

  14. Nitrous Oxide Anesthesia and Plasma Homocysteine in Adolescents

    Science.gov (United States)

    Nagele, Peter; Tallchief, Danielle; Blood, Jane; Sharma, Anshuman; Kharasch, Evan D.

    2011-01-01

    Background Nitrous oxide inactivates vitamin B12, inhibits methionine synthase and consequently increases plasma total homocysteine (tHcy). Prolonged exposure to nitrous oxide can lead to neuropathy, spinal cord degeneration and even death in children. We tested the hypothesis that nitrous oxide anesthesia causes a significant increase in plasma tHcy in children. Methods Twenty-seven children (age 10-18 years) undergoing elective major spine surgery were enrolled and serial plasma samples from 0 – 96 hours after induction were obtained. The anesthetic regimen, including the use of nitrous oxide, was at the discretion of the anesthesiologist. Plasma tHcy was measured using standard enzymatic assays. Results The median baseline plasma tHcy concentration was 5.1 μmol/L (3.9 – 8.0 μmol/L, interquartile range) and increased in all patients exposed to nitrous oxide (n=26) by an average of +9.4 μmol/L (geometric mean; 95% CI 7.1 – 12.5 μmol/L) or +228% (mean; 95% CI 178% - 279%). Plasma tHcy peaked between 6-8 hours after induction of anesthesia. One patient who did not receive nitrous oxide had no increase in plasma tHcy. Several patients experienced a several-fold increase in plasma tHcy (max. +567%). The increase in plasma tHcy was strongly correlated with the duration and average concentration of nitrous oxide anesthesia (r= 0.80; pnitrous oxide anesthesia develop significantly increased plasma tHcy concentrations. The magnitude of this effect appears to be greater compared to adults; however, the clinical relevance is unknown. PMID:21680854

  15. Phenomenological theory of current-producing processes at the solid oxide electrolyte/gas electrode interface: steady-state polarization of fuel-cell electrodes

    International Nuclear Information System (INIS)

    Murygin, I.V.; Chebotin, V.N.

    1979-01-01

    The polarization of fuel-cell electrodes (mixtures CO + CO 2 and H 2 + H 2 O) in systems with solid oxide electrolytes is discussed. The theory is based upon a process model where the electrode reaction zone can spread along the line of three-phase contact by diffusion of reaction partners and products across the electrolyte/electrode and electrolyte/gas interface

  16. Influence of Electrolyte Chemistry on Morphology and Corrosion Resistance of Micro Arc Oxidation Coatings Deposited on Magnesium

    Science.gov (United States)

    Rama Krishna, L.; Poshal, G.; Sundararajan, G.

    2010-12-01

    In the present work, micro arc oxidation (MAO) coatings were synthesized on magnesium substrate employing 11 different electrolyte compositions containing systematically varied concentrations of sodium silicate (Na2SiO3), potassium hydroxide (KOH), and sodium aluminate (NaAlO2). The resultant coatings were subjected to coating thickness measurement, energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), image analysis, and three-dimensional (3-D) optical profilometry. The corrosion performance of the coatings was evaluated by conducting potentiodynamic polarization tests in 3.5 wt pct NaCl solution. The inter-relationships between the electrolyte chemistry and the resulting chemistry and porosity of the coating, on one hand, and with the aqueous corrosion behavior of the coating, on the other, were studied. The changes in pore morphology and pore distribution in the coatings were found to be significantly influenced by the electrolyte composition. The coatings can have either through-thickness pores or pores in the near surface region alone depending on the electrolyte composition. The deleterious role of KOH especially when its concentration is >20 pct of total electrolyte constituents promoting the formation of large and deep pores in the coating was demonstrated. A reasonable correlation indicating the increasing pore volume implying the increased corrosion was noticed.

  17. Characterization of poly methyl methaacrylate and reduced graphene oxide composite for application as electrolyte in dye sensitized solar cells

    Science.gov (United States)

    Shrivatsav, Roshan; Mahalingam, Vignesh; Lakshmi Narayanan, E. R.; Naveen Balaji, N.; Balu, Murali; Krishna Prasad, R.; Kumaresan, Duraisamy

    2018-04-01

    Quasi-solid state iodide/triiodide redox electrolyte containing reduced graphene oxide and poly (methyl methaacrylate) (RGO-PMMA) composites for the fabrication of more durable, high performance dye sensitized solar cells are prepared. The morphological analysis of prepared RGO-PMMA composites showed formation of spherical like morphologies of RGO dispersed PMMA particles with their macroscopic inter-particle networks having voids. The x ray diffraction and electrical conductivity studies showed the addition of 1 wt% of filler RGO into amorphous PMMA matrix increased the electrical conductivity of the polymer composite about three orders of magnitude from 10‑7 and 10‑4 S cm‑1. Further, the photovoltaic current-voltage analysis of DSSCs with different RGO-PMMA composite based iodide/triiodide redox electrolytes showed the highest power conversion efficiency of 5.38% and the fill factor 0.63 for 2% RGO-PMMA electrolyte. The EIS analysis showed an increased recombination resistance (Rct2) at TiO2 electrode/dye/electrolyte interface due to the better electrical conductivity of RGO with good ionic conductivity in 2% RGO-PMMA composite based redox electrolyte boosted the generation of a high current density and fill factor in their DSSCs.

  18. Characterization of oxidation end product of plasma albumin 'in vivo'.

    Science.gov (United States)

    Musante, Luca; Bruschi, Maurizio; Candiano, Giovanni; Petretto, Andrea; Dimasi, Nazzareno; Del Boccio, Piero; Urbani, Andrea; Rialdi, Giovanni; Ghiggeri, Gian Marco

    2006-10-20

    Anti-oxidants are paradoxically much lower in plasma than inside cells even blood is comparably exposed to the oxidative stress. 'In vitro' models suggest a critical role of albumin as substitutive anti-oxidant in plasma but no proof for this role is available 'in vivo.' Herein, we demonstrate by LC/MS/MS that plasma albumin undergoes massive oxidation in primary nephrotic syndrome, involving stable sulphonation SO3- of the free SH of Cys 34 with +48Da increase in exact mass of the protein (ESI-MS) and formation of a fast moving isoform in the pH range between 5 and 7. Physical-chemical experiments with DSC and fluorescence spectra indicate a thermal stabilization of the structure upon oxidation. This is the first demonstration of massive oxidation of albumin 'in vivo' that reflects a functional role of the protein. Free radicals should be implicated in the pathogenesis of proteinuria in human FSGS.

  19. Effect of hypovolemia, infusion, and oral rehydration on plasma electrolytes, ADH, renin activity, and +G/z/ tolerance

    Science.gov (United States)

    Greenleaf, J. E.; Brock, P. J.; Haines, R. F.; Rositano, S. A.; Montgomery, L. D.; Keil, L. C.

    1977-01-01

    Effects on plasma volume, electrolyte shifts, and +G(z) tolerance induced by: (1) blood withdrawal; (2) blood infusion; and (3) oral fluid intake, were determined at 0.5 G/min in centrifugation tests of six ambulatory male patients, aged 21 to 27 yrs. Hypovolemia induced by withdrawal of 400 ml blood, blood infusion followed by repeated centrifugation, effects of consuming an isotonic drink (0.9% NaCl) to achieve oral rehydration, and donning of red adaptation goggles were studied for effects on acceleration tolerance, pre-acceleration and post-acceleration plasma renin activity (PRA) and plasma vasopressin levels. No significant changes in post-acceleration PRA compared to pre-acceleration PRA were found, and administration of oral rehydration is found as effective as blood replacement in counteracting hypovolemic effects.

  20. A study of integrated cathode assembly for electrolytic reduction of uranium oxide in LiCl-Li2O molten salt

    International Nuclear Information System (INIS)

    Park, Sung Bin; Seo, Jung Seok; Kang, Dae Seung; Kwon, Sun Kil; Park, Seong Won

    2004-01-01

    Interest of electrolytic reduction of uranium oxide is increasing in treatment of spent metal fuels. Argonne National Laboratory (ANL) has reported the experimental results of electrochemical reduction of uranium oxide fuel in bench-scale apparatus with cyclic voltammetry, and has designed high-capacity reduction (HCR) cells and conducted three kg-scale UO 2 reduction runs. From the cyclic voltammograms, the mechanism of electrolytic reduction of metal oxides is analyzed. The uranium oxide in LiCl-Li 2 O is converted to uranium metal according to the two mechanism; direct and indirect electrolytic reduction. In this study, cyclic voltammograms for LiCl-3wt% Li 2 O system and U 3 O 8 -LiCl-3wt% Li 2 O system using the 325-mesh stainless steel screen in cathode assembly have been obtained. Direct electrolytic reduction of uranium oxide in LiCl-3wt% Li 2 O molten salt has been conducted

  1. Implications of electronic short circuiting in plasma sprayed solid oxide fuel cells on electrode performance evaluation by electrochemical impedance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    White, B.D. [Department of Mechanical Engineering, The University of British Columbia, 2054-6250 Applied Sciences Lane, Vancouver, British Columbia (Canada); Kesler, O. [Department of Mechanical and Industrial Engineering, University of Toronto, 5 King' s College Road, Toronto, Ontario (Canada)

    2008-02-15

    Electronic short circuiting of the electrolyte in a solid oxide fuel cell (SOFC) arising from flaws in the plasma spray fabrication process has been found to have a significant effect on the perceived performance of the electrodes, as evaluated by electrochemical impedance spectroscopy (EIS). The presence of a short circuit has been found to lead to the underestimation of the electrode polarization resistance (R{sub p}) and hence an overestimation of electrode performance. The effect is particularly noticeable when electrolyte resistance is relatively high, for example during low to intermediate temperature operation, leading to an obvious deviation from the expected Arrhenius-type temperature dependence of R{sub p}. A method is developed for determining the real electrode performance from measurements of various cell properties, and strategies for eliminating the occurrence of short circuiting in plasma sprayed cells are identified. (author)

  2. Implications of electronic short circuiting in plasma sprayed solid oxide fuel cells on electrode performance evaluation by electrochemical impedance spectroscopy

    Science.gov (United States)

    White, B. D.; Kesler, O.

    Electronic short circuiting of the electrolyte in a solid oxide fuel cell (SOFC) arising from flaws in the plasma spray fabrication process has been found to have a significant effect on the perceived performance of the electrodes, as evaluated by electrochemical impedance spectroscopy (EIS). The presence of a short circuit has been found to lead to the underestimation of the electrode polarization resistance (R p) and hence an overestimation of electrode performance. The effect is particularly noticeable when electrolyte resistance is relatively high, for example during low to intermediate temperature operation, leading to an obvious deviation from the expected Arrhenius-type temperature dependence of R p. A method is developed for determining the real electrode performance from measurements of various cell properties, and strategies for eliminating the occurrence of short circuiting in plasma sprayed cells are identified.

  3. Obtaining of ceria - samaria - gadolinia ceramics for application as solid oxide fuel cell (SOFC) electrolyte

    International Nuclear Information System (INIS)

    Arakaki, Alexander Rodrigo

    2010-01-01

    Cerium oxide (CeO 2 ) when doped with rare earth oxides has its ionic conductivity enhanced, enabling its use as electrolyte for Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFC), which is operated in temperatures between 500 e 700 degree C. The most effective additives or dopants for ionic conductivity improvement are (samarium oxide - Sm 2 O 3 ) and gadolinia (gadolinium oxide - Gd 2 O 3 ), fixing the concentration between 10 and 20 molar%. In this work, Ce 0,8 (SmGd) 0,2 O 1,9 powders have been synthesized by hydroxide, carbonate and oxalate coprecipitation routes. The hydrothermal treatment has been studied for powders precipitated with ammonium hydroxide. A concentrate of rare earths containing 90wt% of CeO 2 and other containing 51% of Sm 2 O 3 and 30% of Gd 2 O 3 , both prepared from monazite processing, were used as starting materials. These concentrates were used due the lower cost compared to pure commercial materials and the chemical similarity of others rare earth elements. Initially, the coprecipitation and calcination conditions were defined. The process efficiency was verified by ceramic sinterability evaluation. The results showed that powders calcined in the range of 450 and 800 degree C presented high specific surface area (90 - 150 m 2 .g -1 ) and fluorite cubic structure, indicating the solid solution formation. It was observed, by scanning electron microscopy, that morphology of particles and agglomerates is a function of precipitant agent. The dilatometric analysis indicated the higher rate of shrinkage at temperatures around 1300-1350 degree C. High densification values (>95% TD) was obtained at temperatures above 1400 degree C. Synthesis by hydroxides coprecipitation followed by hydrothermal treatment demonstrated to be a promising route for crystallization of ceria nano powders at low temperatures (200 degree C). High values of specific surface area were reached with the employment of hydrothermal treatment (about 100 m 2 .g -1

  4. A study on optical properties of poly (ethylene oxide) based polymer electrolyte with different alkali metal iodides

    Science.gov (United States)

    Rao, B. Narasimha; Suvarna, R. Padma

    2016-05-01

    Polymer electrolytes were prepared by adding poly (ethylene glycol) dimethyl ether (PEGDME), TiO2 (nano filler), different alkali metal iodide salts RI (R+=Li+, Na+, K+, Rb+, Cs+) and I2 into Acetonitrile gelated with Poly (ethylene oxide) (PEO). Optical properties of poly (ethylene oxide) based polymer electrolytes were studied by FTIR, UV-Vis spectroscopic techniques. FTIR spectrum reveals that the alkali metal cations were coordinated to ether oxygen of PEO. The optical absorption studies were made in the wavelength range 200-800 nm. It is observed that the optical absorption increases with increase in the radius of alkali metal cation. The optical band gap for allowed direct transitions was evaluated using Urbach-edges method. The optical properties such as optical band gap, refractive index and extinction coefficient were determined. The studied polymer materials are useful for solar cells, super capacitors, fuel cells, gas sensors etc.

  5. Electrolytic Production of Ti5Si3/TiC Composites by Solid Oxide Membrane Technology

    Science.gov (United States)

    Zheng, Kai; Zou, Xingli; Xie, Xueliang; Lu, Changyuan; Chen, Chaoyi; Xu, Qian; Lu, Xionggang

    2018-02-01

    This paper investigated the electrolytic production of Ti5Si3/TiC composites from TiO2/SiO2/C in molten CaCl2. The solid-oxide oxygen-ion-conducting membrane tube filled with carbon-saturated liquid tin was served as the anode, and the pressed spherical TiO2/SiO2/C pellet was used as the cathode. The electrochemical reduction process was carried out at 1273 K and 3.8 V. The characteristics of the obtained cathode products and the reaction mechanism of the electroreduction process were studied by a series of time-dependent electroreduction experiments. It was found that the electroreduction process generally proceeds through the following steps: TiO2/SiO2/C → Ti2O3, CaTiO3, Ca2SiO4, SiC → Ti5Si3, TiC. The morphology observation and the elemental distribution analysis indicate that the reaction routes for Ti5Si3 and TiC products are independent during the electroreduction process.

  6. Small cell experiments for electrolytic reduction of uranium oxides to uranium metal using fluoride salts

    International Nuclear Information System (INIS)

    Haas, P.A.; Adcock, P.W.; Coroneos, A.C.; Hendrix, D.E.

    1994-01-01

    Electrolytic reduction of uranium oxide was proposed for the preparation of uranium metal feed for the atomic vapor laser isotope separation (AVLIS) process. A laboratory cell of 25-cm ID was operated to obtain additional information in areas important to design and operation of a pilot plant cell. Reproducible test results and useful operating and control procedures were demonstrated. About 20 kg of uranium metal of acceptable purity were prepared. A good supply of dissolved UO 2 feed at the anode is the most important controlling requirement for efficient cell operation. A large fraction of the cell current is nonproductive in that it does not produce a metal product nor consume carbon anodes. All useful test conditions gave some reduction of UF 4 to produce CF 4 in addition to the reduction of UO 2 , but the fraction of metal from the reduction of UF 4 can be decreased by increasing the concentration of dissolved UO 2 . Operation of large continuous cells would probably be limited to current efficiencies of less than 60 pct, and more than 20 pct of the metal would result from the reduction of UF 4

  7. Oxides with polyatomic anions considered as new electrolyte materials for solid oxide fuel cells (SOFCs)

    Energy Technology Data Exchange (ETDEWEB)

    Bin Hassan, Oskar Hasdinor

    2010-10-21

    Materials with Polyatomic anions of [Al{sub 2}O{sub 7}]{sup -8}, [Ti{sub 2}O{sub 8}]{sup -8} and [P{sub 2}O{sub 7}]{sup -4} were investigated with respect to their ionic conductivity properties as well as its thermal expansion properties with the aim to use them as SOFCs electrolytes. The polyatomic anion groups selected from the oxy-cuspidine family of Gd{sub 4}Al{sub 2}O{sub 9} and Gd{sub 4}Ti{sub 2}O{sub 10} as well as from pyrophosphate SnP{sub 2}O{sub 7}. The pure oxy-cuspidine Gd{sub 4}Al{sub 2}O{sub 9}, the series of Gd{sub 4}Al{sub 2-x}Mg{sub x}O{sub 9-x/2} with x=0.10-1.0 and Gd{sub 4-x}M{sub x}Al{sub 2}O{sub 9-x/2} (M=Ca, Sr) with x = 0.05-0.5 were prepared successfully by the citrate complexation method. All samples showed the crystal structure of monoclinic oxycuspidine structure with space group of P2{sub 1/c} and Z=4. No solid solution was observed for Gd{sub 4}Al{sub 2-x}Mg{sub x}O{sub 9-x/2} where additional phases of Gd{sub 2}O{sub 3} and MgO were presence. XRD semiquantitative analysis together with SEM-EDX analysis revealed that Mg{sup 2+} was not able to substitute the Al{sup 3+} ions even at low Mg{sup 2+} concentration. The solid solution limit of Gd{sub 4-x}Ca{sub x}Al{sub 2}O{sub 9-x/2} and Gd{sub 4-x}Sr{sub x}Al{sub 2}O{sub 9-x/2} was determined between 0.05-0.10 and 0.01-0.05 mol for Ca and Sr, respectively. Beyond the substitution limit Gd{sub 4}Al{sub 2}O{sub 9}, GdAlO{sub 3} and SrGd{sub 2}Al{sub 2}O{sub 7} appeared as additional phases. The highest electrical conductivity obtained at 900 C yielded {sigma}= 1.49 x 10{sup -4}Scm{sup -1} for Gd{sub 3.95}Ca{sub 0.05}Al{sub 2}O{sub 8.98}. In comparison, the conductivity of pure Gd{sub 4}Al{sub 2}O{sub 9} was {sigma}= 1.73 x 10{sup -5} Scm{sup -1}. The conductivities determined were in a similar range as those of other cuspidine materials investigated previously. The thermal expansion coefficient of Gd{sub 4}Al{sub 2}O{sub 9} at 1000 C was 7.4 x 10{sup -6}K{sup -1}. The earlier reported

  8. Plasma and catalyst for the oxidation of NOx

    DEFF Research Database (Denmark)

    Jõgi, Indrek; Erme, Kalev; Levoll, Erik

    2018-01-01

    . In the case of indirect oxidation, only ozone could reach the catalyst surface and improve the oxidation of NO2 to N2O5. The effect of catalyst at different experimental conditions was quantitatively described with the aid of simple global chemical kinetic models derived for the NO x oxidation either...... by plasma or ozone. The models allowed to compare the effect of different catalysts and to analyze the limitations for the efficiency improvement by catalyst....... to NO mediated by O radicals in plasma. Indirect NO oxidation by plasma produced ozone allows to circumvent the back-reaction and further oxidize NO2 to N2O5 but the slow reaction rate for the latter process limits the efficiency of this process. Present paper gives an overview of the role of metal...

  9. Low temperature solid oxide fuel cells with proton-conducting Y:BaZrO{sub 3} electrolyte on porous anodic aluminum oxide substrate

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Seungbum [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); School of Mechanical and Aerospace Engineering, Seoul National University, Daehak-dong, Gwanak-gu, Seoul 151–742 (Korea, Republic of); Su, Pei-Chen [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Ji, Sanghoon [Graduate School of Convergence Science and Technology, Seoul National University, Daehak-dong, Gwanak-gu, Seoul 151–742 (Korea, Republic of); Cha, Suk Won, E-mail: swcha@snu.ac.kr [School of Mechanical and Aerospace Engineering, Seoul National University, Daehak-dong, Gwanak-gu, Seoul 151–742 (Korea, Republic of)

    2013-10-01

    This paper presents the architecture of a nano thin-film yttrium-doped barium zirconate (BYZ) solid-oxide fuel cell that uses nanoporous anodic aluminum oxide (AAO) as a supporting and gas-permeable substrate. The anode was fabricated by sputtering 300 nm platinum thin film that partially covered the AAO surface pores, followed by an additional conformal platinum coating to tune the pore size by atomic layer deposition. Two different nano-porous anode structures with a pore size of 10 nm or 50 nm were deposited. Proton-conducting BYZ ceramic electrolyte with increasing thicknesses of 300, 600, and 900 nm was deposited on top of the platinum anode by pulsed laser deposition, followed by a 200 nm layer of porous Pt sputtered on BYZ electrolyte as a cathode. The open circuit voltage (OCV) of the fuel cells was characterized at 250 °C with 1:1 volumetric stoichiometry of a methanol/water vapor mixture as the fuel. The OCVs were 0.17 V with a 900 nm-thick BYZ electrolyte on 50 nm pores and 0.3 V with a 600 nm-thick BYZ electrolyte on 10 nm pores, respectively, but it increased to 0.8 V for a 900 nm-thick BYZ electrolyte on 10 nm pores, indicating that increasing the film thickness and decreasing a surface pore size help to reduce the number of electrolyte pinholes and the gas leakage through the electrolyte. A maximum power density of 5.6 mW/cm{sup 2} at 250 °C was obtained from the fuel cell with 900 nm of BYZ electrolyte using methanol vapor as a fuel. - Highlights: • A low temperature ceramic fuel cell on nano-porous substrate was demonstrated. • A thin-film yttrium doped barium zirconate (BYZ) was deposited as an electrolyte. • An open circuit voltage (OCV) was measured to verify the BYZ film quality. • An OCV increased by increasing BYZ film thickness and decreasing pore size of anode. • The current–voltage performance was measured using vaporized methanol fuel at 250 °C.

  10. Preparation and Properties of Poly (vinylidene fluoride)/poly(dimethylsiloxane) graft (poly(propylene oxide)-block-poly(ethylene oxide)) blend porous separators and corresponding electrolytes

    International Nuclear Information System (INIS)

    Li, Hao; Zhang, Hong; Liang, Zhi-Ying; Chen, Yue-Ming; Zhu, Bao-Ku; Zhu, Li-Ping

    2014-01-01

    Highlights: •This work aims exploring microporous PVDF separators for lithium ion batteries. •Comb structure polymer PDMS-g-(PPO-PEO) was used in PVDF blend separators. •The influence of polyether side chains on interfacial resistance was studied. -- Abstract: This work aims exploring the high performance porous separators that can be activated into gel electrolyte membranes for lithium ion batteries. A comb-like copolymer poly (dimethylsiloxane) graft poly (propylene oxide)-block-poly (ethylene oxide) (PDMS-g-(PPO-PEO)) was synthesized and blended with poly (vinylidene fluoride) (PVDF) to fabricate porous separators via a typical phase inversion process, and then the separators absorbed liquid electrolyte solution and formed into polymer electrolyte membranes. By measuring the composition, morphology and ion conductivity etc, the influence of PDMS-g-(PPO-PEO) on structure and properties of blend separators were discussed. Compared with pure PVDF separator with comparable porous structure, the adoption of PDMS-g-(PPO-PEO) decreased the crystallinity and increased the liquid electrolyte uptake and stability effectively. It was also found that the electrode/electrolyte interfacial resistance could be reduced greatly. The resulting electrolyte membrane using separator with PVDF/PDMS-g-(PPO-PEO) mass ratio in 8/2 exhibited highest ionic conductivity in 4.5 × 10 −3 S/cm at room temperature, while the electrochemical stability was up to 4.7 V (vs. Li/Li + ). Coin cells assembled with such separators also exhibited stable cycle performance and improved rate capabilities, especially when discharge rate higher than 0.5 C

  11. About the Compatibility between High Voltage Spinel Cathode Materials and Solid Oxide Electrolytes as a Function of Temperature.

    Science.gov (United States)

    Miara, Lincoln; Windmüller, Anna; Tsai, Chih-Long; Richards, William D; Ma, Qianli; Uhlenbruck, Sven; Guillon, Olivier; Ceder, Gerbrand

    2016-10-12

    The reactivity of mixtures of high voltage spinel cathode materials Li 2 NiMn 3 O 8 , Li 2 FeMn 3 O 8 , and LiCoMnO 4 cosintered with Li 1.5 Al 0.5 Ti 1.5 (PO 4 ) 3 and Li 6.6 La 3 Zr 1.6 Ta 0.4 O 12 electrolytes is studied by thermal analysis using X-ray-diffraction and differential thermoanalysis and thermogravimetry coupled with mass spectrometry. The results are compared with predicted decomposition reactions from first-principles calculations. Decomposition of the mixtures begins at 600 °C, significantly lower than the decomposition temperature of any component, especially the electrolytes. For the cathode + Li 6.6 La 3 Zr 1.6 Ta 0.4 O 12 mixtures, lithium and oxygen from the electrolyte react with the cathodes to form highly stable Li 2 MnO 3 and then decompose to form stable and often insulating phases such as La 2 Zr 2 O 7 , La 2 O 3 , La 3 TaO 7 , TiO 2 , and LaMnO 3 which are likely to increase the interfacial impedance of a cathode composite. The decomposition reactions are identified with high fidelity by first-principles calculations. For the cathode + Li 1.5 Al 0.5 Ti 1.5 (PO 4 ) 3 mixtures, the Mn tends to oxidize to MnO 2 or Mn 2 O 3 , supplying lithium to the electrolyte for the formation of Li 3 PO 4 and metal phosphates such as AlPO 4 and LiMPO 4 (M = Mn, Ni). The results indicate that high temperature cosintering to form dense cathode composites between spinel cathodes and oxide electrolytes will produce high impedance interfacial products, complicating solid state battery manufacturing.

  12. In-situ preparation of poly(ethylene oxide)/Li3PS4 hybrid polymer electrolyte with good nanofiller distribution for rechargeable solid-state lithium batteries

    Science.gov (United States)

    Chen, Shaojie; Wang, Junye; Zhang, Zhihua; Wu, Linbin; Yao, Lili; Wei, Zhenyao; Deng, Yonghong; Xie, Dongjiu; Yao, Xiayin; Xu, Xiaoxiong

    2018-05-01

    Nano-sized fillers in a polymer matrix with good distribution can play a positive role in improving polymer electrolytes in the aspects of ionic conductivity, mechanical property and electrochemical performance of Li-ion cells. Herein, polyethylene oxide (PEO)/Li3PS4 hybrid polymer electrolyte is prepared via a new in-situ approach. The ionic conductivities of the novel hybrid electrolytes with variable proportions are measured, and the optimal electrolyte of PEO-2%vol Li3PS4 presents a considerable ionic conductivity of 8.01 × 10-4 S cm-1 at 60 °C and an electrochemical window up to 5.1 V. The tests of DSC and EDXS reveal that the Li3PS4 nanoparticles with better distribution, as active fillers scattering in the PEO, exhibit a positive effect on the transference of lithium ion and electrochemical interfacial stabilities. Finally, the assembled solid-state LiFePO4/Li battery presents a decent cycling performance (80.9% retention rate after 325 cycles at 60 °C) and excellent rate capacities with 153, 143, 139 and 127 mAh g-1 at the discharging rate of 0.1 C, 0.2 C, 0.5 C and 1 C at 60 °C. It is fully proved that it is an advanced strategy to preparing the new organic/inorganic hybrid electrolytes for lithium-ion batteries applications.

  13. Oxidation of vanadium metal in oxygen plasma and their characterizations

    Science.gov (United States)

    Sharma, Rabindar Kumar; Singh, Megha; Kumar, Prabhat; Reddy, G. B.

    2015-09-01

    In this report, the role of oxygen plasma on oxidation of vanadium (V) metal and the volatilization of its oxides has been studied as a function of source (V metal strip) temperature (Tss) and oxygen partial pressure (PO2). The presence of O2-plasma not only enhances the oxidation rate but also ficilitates in transport of oxide molecules from metal to substrate, as confirmed by the simultanous deposition of oxide film onto substrate. Both the oxidized metal strips and oxide films deposited on substrates are characterized separately. The structural and vibrational results evidence the presence of two different oxide phases (i.e. orthorhombic V2O5 and monocilinic V O2) in oxide layers formed on V metal strips, whereas the oxide films deposited on substrates exhibit only orthorhombic phase (i.e. V2O5). The decrease in peak intensities recorded from heated V metal strips on increasing Tss points out the increment in the rate of oxide volatilization, which also confirms by the oxide layer thickness measurements. The SEM results show the noticeable surface changes on V-strips as the function of Tss and PO2 and their optimum values are recorded to be 500 ˚ C and 7.5 × 10-2 Torr, respectively to deposit maximum thick oxide film on substrate. The formation of microcracks on oxidized V-strips, those responsible to countinue oxidation is also confirmed by SEM results. The compositional study of oxide layers formed on V-strips, corroborates their pureness and further assures about the existence of mixed oxide phases. The effect of oxygen partial pressure on oxidation of V-metal has also been discussed in the present report. All the results are well in agreement to each other.

  14. Effect of alumina sol addition to micro-arc oxidation electrolyte on the properties of MAO coatings formed on magnesium alloy AZ91D

    International Nuclear Information System (INIS)

    Laleh, M.; Rouhaghdam, A. Sabour; Shahrabi, T.; Shanghi, A.

    2010-01-01

    Oxide coatings were formed on AZ91D magnesium alloy using micro-arc oxidation process in alkaline electrolyte without and with addition of alumina sol. The microstructures and compositions of the MAO coatings were analyzed by scanning electron microscope (SEM) and X-ray diffraction (XRD). Corrosion behaviors of the coatings were evaluated with electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests in 3.5%NaCl solution. Porosities of the coatings were measured by potentiodynamic polarization tests. It was found that the coating produced in the electrolyte with alumina sol has more compact and uniform morphology than that produced in the electrolyte without alumina sol. The results of corrosion tests showed that the coating formed in electrolyte with alumina sol enhances the corrosion resistance of the substrate significantly. XRD patterns showed that the coating produced in the electrolyte with alumina sol has more MgAl 2 O 4 phase than MgO.

  15. Nanographene synthesized in triple-phase plasmas as a highly durable support of catalysts for polymer electrolyte fuel cells

    Science.gov (United States)

    Amano, Tomoki; Kondo, Hiroki; Takeda, Keigo; Ishikawa, Kenji; Hiramatsu, Mineo; Sekine, Makoto; Hori, Masaru

    2018-04-01

    Nanographene was synthesized in triple-phase plasmas comprising a gaseous phase, a gas-liquid boundary layer, and an in-liquid phase using a setup in which one electrode was placed in the gaseous phase while the other was immersed in the liquid phase. The triple-phase plasmas were generated using a pure alcohol, such as ethanol, 1-propanol, or 1-butanol, by applying a high voltage to a pair of electrodes made of copper or graphite. The nanographene synthesized using ethanol had high durability and thus could serve as a catalyst support in polymer electrolyte fuel cells (PEFCs). The PEFCs exhibited low degradation rates in the high-potential cycle test of a half-cell, as a result of which, a loss of only 10% was observed in the effective electrochemical surface area of Pt, even after 10,000 cycles.

  16. Study of the Electrolytic Reduction of Uranium Oxide in LiCl-Li2O Molten Salts with an Integrated Cathode Assembly

    International Nuclear Information System (INIS)

    Park, Sung Bin; Seo, Chung Seok; Kang, Dae Seung; Kwon, Seon Gil; Park, Seong Won

    2005-01-01

    The electrolytic reduction of uranium oxide in a LiCl-Li 2 O molten salt system has been studied in a 10 g U 3 O 3 /batch-scale experimental apparatus with an integrated cathode assembly at 650 .deg. C. The integrated cathode assembly consists of an electric conductor, the uranium oxide to be reduced and the membrane for loading the uranium oxide. From the cyclic voltammograms for the LiCl-3 wt% Li 3 O system and the U 3 O 3 -LiCl-3 wt% Li 2 O system according to the materials of the membrane in the cathode assembly, the mechanisms of the predominant reduction reactions in the electrolytic reactor cell were to be understood; direct and indirect electrolytic reduction of uranium oxide. Direct and indirect electrolytic reductions have been performed with the integrated cathode assembly. Using the 325-mesh stainless steel screen the uranium oxide failed to be reduced to uranium metal by a direct and indirect electrolytic reduction because of a low current efficiency and with the porous magnesia membrane the uranium oxide was reduced successfully to uranium metal by an indirect electrolytic reduction because of a high current efficiency.

  17. Enhanced lithium battery with polyethylene oxide-based electrolyte containing silane-Al2 O3 ceramic filler.

    Science.gov (United States)

    Zewde, Berhanu W; Admassie, Shimelis; Zimmermann, Jutta; Isfort, Christian Schulze; Scrosati, Bruno; Hassoun, Jusef

    2013-08-01

    A solid polymer electrolyte prepared by using a solvent-free, scalable technique is reported. The membrane is formed by low-energy ball milling followed by hot-pressing of dry powdered polyethylene oxide polymer, LiCF3 SO3 salt, and silane-treated Al2 O3 (Al2 O3 -ST) ceramic filler. The effects of the ceramic fillers on the properties of the ionically conducting solid electrolyte membrane are characterized by using electrochemical impedance spectroscopy, XRD, differential scanning calorimeter, SEM, and galvanostatic cycling in lithium cells with a LiFePO4 cathode. We demonstrate that the membrane containing Al2 O3 -ST ceramic filler performs well in terms of ionic conductivity, thermal properties, and lithium transference number. Furthermore, we show that the lithium cells, which use the new electrolyte together with the LiFePO4 electrode, operate within 65 and 90 °C with high efficiency and long cycle life. Hence, the Al2 O3 -ST ceramic can be efficiently used as a ceramic filler to enhance the performance of solid polymer electrolytes in lithium batteries. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Enhanced electrochemical performance of in situ reduced graphene oxide-polyaniline nanotubes hybrid nanocomposites using redox-additive aqueous electrolyte

    Science.gov (United States)

    Devi, Madhabi; Kumar, A.

    2018-02-01

    Reduced graphene oxide (RGO)-polyaniline nanotubes (PAniNTs) nanocomposites have been synthesized by in situ reduction of GO. The morphology and structure of the nanocomposites are characterized by HRTEM, XRD and micro-Raman spectroscopy. The electrical and electrochemical performances of the nanocomposites are investigated for different RGO concentrations by conductivity measurements, cyclic voltammetry, charge-discharge and electrochemical impedance spectroscopy. Highest gravimetric specific capacitance of 448.71 F g-1 is obtained for 40 wt.% of RGO-PAniNTs nanocomposite as compared to 194.92 F g-1 for pure PAniNTs in 1 M KCl electrolyte. To further improve the electrochemical performance of the nanocomposite electrode, KI is used as redox-additive with 1 M KCl electrolyte. Highest gravimetric specific capacitance of 876.43 F g-1 and an improved cyclic stability of 91% as compared to 79% without KI after 5000 cycles is achieved for an optimized 0.1 M KI concentration. This is attributed to the presence of different ionic species of I- ions that give rise to a number of possible redox reactions improving the pseudocapacitance of the electrode. This improved capacitive performance is compared with that of catechol redox-additive in 1 M KCl electrolyte, and that of KI and catechol redox-additives added to 1 M H2SO4 electrolyte.

  19. Comparison of direct and indirect plasma oxidation of NO combined with oxidation by catalyst

    DEFF Research Database (Denmark)

    Jogi, Indrek; Stamate, Eugen; Irimiea, Cornelia

    2015-01-01

    of the DBD reactor decreased the long-term efficiency of direct plasma oxidation. At the same time, the efficiency of indirect oxidation increased at elevated reactor temperatures. Additional experiments were carried out to investigate the improvement of indirect oxidation by the introduction of catalyst...

  20. Control of morphology and surface wettability of anodic niobium oxide microcones formed in hot phosphate-glycerol electrolytes

    International Nuclear Information System (INIS)

    Yang, Shu; Habazaki, Hiroki; Fujii, Takashi; Aoki, Yoshitaka; Skeldon, Peter; Thompson, George E.

    2011-01-01

    Highlights: → Anodic niobium oxide microcones with nanofiber morphology are formed simply by anodizing. → The cone size and its tip angle are controlled by anodizing condition. → The surface shows extremely high contact angle for water after coating with a fluoroalkyl layer. - Abstract: We report the fabrication of superhydrophobic surfaces with a hierarchical morphology by self-organized anodizing process. Simply by anodizing of niobium metal in hot phosphate-glycerol electrolyte, niobium oxide microcones, consisting of highly branched oxide nanofibers, develop on the surface. The size of the microcones and their tip angles are controlled by changing the applied potential difference in anodizing and the water content in the electrolyte. Reduction of the water content increases the size of the microcones, with the nanofibers changing to nanoparticles. The size of microcones is also reduced by increasing the applied potential difference, without influencing the tip angle. The hierarchical oxide surfaces are superhydrophilic, with static contact angles close to 0 o . Coating of the anodic oxide films with a monolayer of fluoroalkyl phosphate makes the surfaces superhydrophobic with a contact angle for water as high as 175 o and a very small contact angle hysteresis of only 2 o . The present results indicate that the larger microcones with smaller tip angles show the higher contact angle for water.

  1. Effect of proton-conduction in electrolyte on electric efficiency of multi-stage solid oxide fuel cells

    Science.gov (United States)

    Matsuzaki, Yoshio; Tachikawa, Yuya; Somekawa, Takaaki; Hatae, Toru; Matsumoto, Hiroshige; Taniguchi, Shunsuke; Sasaki, Kazunari

    2015-07-01

    Solid oxide fuel cells (SOFCs) are promising electrochemical devices that enable the highest fuel-to-electricity conversion efficiencies under high operating temperatures. The concept of multi-stage electrochemical oxidation using SOFCs has been proposed and studied over the past several decades for further improving the electrical efficiency. However, the improvement is limited by fuel dilution downstream of the fuel flow. Therefore, evolved technologies are required to achieve considerably higher electrical efficiencies. Here we present an innovative concept for a critically-high fuel-to-electricity conversion efficiency of up to 85% based on the lower heating value (LHV), in which a high-temperature multi-stage electrochemical oxidation is combined with a proton-conducting solid electrolyte. Switching a solid electrolyte material from a conventional oxide-ion conducting material to a proton-conducting material under the high-temperature multi-stage electrochemical oxidation mechanism has proven to be highly advantageous for the electrical efficiency. The DC efficiency of 85% (LHV) corresponds to a net AC efficiency of approximately 76% (LHV), where the net AC efficiency refers to the transmission-end AC efficiency. This evolved concept will yield a considerably higher efficiency with a much smaller generation capacity than the state-of-the-art several tens-of-MW-class most advanced combined cycle (MACC).

  2. Simulation of uranium and plutonium oxides compounds obtained in plasma

    Science.gov (United States)

    Novoselov, Ivan Yu.; Karengin, Alexander G.; Babaev, Renat G.

    2018-03-01

    The aim of this paper is to carry out thermodynamic simulation of mixed plutonium and uranium oxides compounds obtained after plasma treatment of plutonium and uranium nitrates and to determine optimal water-salt-organic mixture composition as well as conditions for their plasma treatment (temperature, air mass fraction). Authors conclude that it needs to complete the treatment of nitric solutions in form of water-salt-organic mixtures to guarantee energy saving obtainment of oxide compounds for mixed-oxide fuel and explain the choice of chemical composition of water-salt-organic mixture. It has been confirmed that temperature of 1200 °C is optimal to practice the process. Authors have demonstrated that condensed products after plasma treatment of water-salt-organic mixture contains targeted products (uranium and plutonium oxides) and gaseous products are environmental friendly. In conclusion basic operational modes for practicing the process are showed.

  3. Manganese oxide electrochemical capacitor with potassium poly(acrylate) hydrogel electrolyte

    Science.gov (United States)

    Lee, Kuang-Tsin; Wu, Nae-Lih

    An aqueous gel electrolyte has for the first time been successfully applied to the MnO 2· nH 2O-based pseudocapacitive electrochemical capacitors (ECs). The gel electrolyte is made of potassium poly(acrylate) (PAAK) polymer and aqueous solution of KCl. With the selected composition, PAAK:KCl:H 2O = 9.0%:6.7%:84.3% by weight, the gel shows no fluidity, possessing an ionic conductivity in the order of 10 -1 S cm -1. The gel electrolyte has been found to give substantially higher specific capacitances than those in the liquid electrolyte with the same salt (KCl) composition (1 M) and high power capability (>10 kW/kg).

  4. Manganese oxide electrochemical capacitor with potassium poly(acrylate) hydrogel electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kuang-Tsin; Wu, Nae-Lih [Department of Chemical Engineering, National Taiwan University, Taipei 106 (China)

    2008-04-15

    An aqueous gel electrolyte has for the first time been successfully applied to the MnO{sub 2}.nH{sub 2}O-based pseudocapacitive electrochemical capacitors (ECs). The gel electrolyte is made of potassium poly(acrylate) (PAAK) polymer and aqueous solution of KCl. With the selected composition, PAAK:KCl:H{sub 2}O = 9.0%:6.7%:84.3% by weight, the gel shows no fluidity, possessing an ionic conductivity in the order of 10{sup -1} S cm{sup -1}. The gel electrolyte has been found to give substantially higher specific capacitances than those in the liquid electrolyte with the same salt (KCl) composition (1 M) and high power capability (>10 kW/kg). (author)

  5. Hypochlorite-induced oxidation of proteins in plasma

    DEFF Research Database (Denmark)

    Hawkins, C L; Davies, Michael Jonathan

    1999-01-01

    Activated phagocyte cells generate hypochlorite (HOCl) via the release of H2O2 and the enzyme myeloperoxidase. Plasma proteins are major targets for HOCl, although little information is available about the mechanism(s) of oxidation. In this study the reaction of HOCl (at least 50 microM) with dil......Activated phagocyte cells generate hypochlorite (HOCl) via the release of H2O2 and the enzyme myeloperoxidase. Plasma proteins are major targets for HOCl, although little information is available about the mechanism(s) of oxidation. In this study the reaction of HOCl (at least 50 micro......M) with diluted fresh human plasma has been shown to generate material that oxidizes 5-thio-2-nitrobenzoic acid; these oxidants are believed to be chloramines formed from the reaction of HOCl with protein amine groups. Chloramines have also been detected with isolated plasma proteins treated with HOCl. In both...... more efficient. The reaction of fresh diluted plasma with HOCl also gives rise to protein-derived nitrogen-centred radicals in a time- and HOCl-concentration-dependent manner; these have been detected by EPR spin trapping. Identical radicals have been detected with isolated HOCl-treated plasma proteins...

  6. Effect of succinonitrile on electrical, structural, optical, and thermal properties of [poly(ethylene oxide)-succinonitrile]/LiI–I2 redox-couple solid polymer electrolyte

    International Nuclear Information System (INIS)

    Gupta, Ravindra Kumar; Rhee, Hee-Woo

    2012-01-01

    Effect of succinonitrile on electrical, structural, optical, and thermal properties of [poly(ethylene oxide)-succinonitrile]/LiI–I 2 redox-couple solid polymer electrolyte is reported for the first time. For the poly(ethylene oxide)-succinonitrile blend-based electrolyte electrical conductivity was noted as high as ∼3 × 10 −4 S cm −1 at 25 °C, which is an order of magnitude higher than that of pure poly(ethylene oxide)-based electrolyte. It also exhibited relatively better pseudo-activation energy (∼0.08 eV). X-ray diffractometry, polarized optical microscopy, and differential scanning calorimetry studies revealed that succinonitrile is helpful in reducing the poly(ethylene oxide) crystallinity due to its plasticizing property. FT-IR study showed significant modification of the poly(ethylene oxide) chain conformation due to the succinonitrile.

  7. Plasma processes and film growth of expanding thermal plasma deposited textured zinc oxide

    NARCIS (Netherlands)

    Groenen, R.; Linden, J.L.; Sanden, van de M.C.M.

    2005-01-01

    Plasma processes and film growth of textured zinc oxide deposited from oxygen and diethyl zinc utilizing expanding thermal argon plasma created by a cascaded arc is discussed. In all conditions explored, an excess of argon ions and low temperature electrons is available, which represent the

  8. High optical and switching performance electrochromic devices based on a zinc oxide nanowire with poly(methyl methacrylate) gel electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Young Tea; Chu, Daping, E-mail: dpc31@cam.ac.uk [Electrical Engineering Division, Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Neeves, Matthew; Placido, Frank [Thin Film Centre, University of the West of Scotland, Paisley PA1 2BE (United Kingdom); Smithwick, Quinn [Disney Research, 521 Circle Seven Drive, Glendale, Los Angeles, California 91201 (United States)

    2014-11-10

    High performance electrochromic devices have been fabricated and demonstrated utilizing a solid polymer electrolyte and zinc oxide (ZnO) nanowire (NW) array counter electrode. The poly(methyl methacrylate) based polymer electrolyte was spin coated upon hydrothermally grown ZnO NW array counter electrodes, while electron beam evaporated NiO{sub x} thin films formed the working electrodes. Excellent optical contrast and switching speeds were observed in the fabricated devices with active areas of 2 cm{sup 2}, exhibiting an optical contrast of 73.11% at the wavelength of 470 nm, combined with a fast switching time of 0.2 s and 0.4 s for bleaching and coloration, respectively.

  9. Nanoporous palladium anode for direct ethanol solid oxide fuel cells with nanoscale proton-conducting ceramic electrolyte

    Science.gov (United States)

    Li, Yong; Wong, Lai Mun; Xie, Hanlin; Wang, Shijie; Su, Pei-Chen

    2017-02-01

    In this work, we demonstrate the operation of micro-solid oxide fuel cells (μ-SOFCs) with nanoscale proton-conducting Y-BaZrO3 (BZY) electrolyte to avoid the fuel crossover problem for direct ethanol fuel cells (DEFCs). The μ-SOFCs are operated with the direct utilisation of ethanol vapour as a fuel and Pd as anode at the temperature range of 300-400 °C. The nanoporous Pd anode is achieved by DC sputtering at high Ar pressure of 80 mTorr. The Pd-anode/BYZ-electrolyte/Pt-cathode cell show peak power densities of 72.4 mW/cm2 using hydrogen and 15.3 mW/cm2 using ethanol at 400 °C. No obvious carbon deposition is seen from XPS analysis after fuel cell test with ethanol fuel.

  10. High optical and switching performance electrochromic devices based on a zinc oxide nanowire with poly(methyl methacrylate) gel electrolytes

    International Nuclear Information System (INIS)

    Chun, Young Tea; Chu, Daping; Neeves, Matthew; Placido, Frank; Smithwick, Quinn

    2014-01-01

    High performance electrochromic devices have been fabricated and demonstrated utilizing a solid polymer electrolyte and zinc oxide (ZnO) nanowire (NW) array counter electrode. The poly(methyl methacrylate) based polymer electrolyte was spin coated upon hydrothermally grown ZnO NW array counter electrodes, while electron beam evaporated NiO x thin films formed the working electrodes. Excellent optical contrast and switching speeds were observed in the fabricated devices with active areas of 2 cm 2 , exhibiting an optical contrast of 73.11% at the wavelength of 470 nm, combined with a fast switching time of 0.2 s and 0.4 s for bleaching and coloration, respectively

  11. Plasma Deposition of Oxide-Coated Cathodes

    National Research Council Canada - National Science Library

    Umstattd, Ryan

    1998-01-01

    ...; such cathodes may also have applicability for lower current density continuous wave devices. This novel approach to manufacturing an oxide cathode eliminates the binders that may subsequently (and unpredictably...

  12. Plasma and catalyst for the oxidation of NOx

    DEFF Research Database (Denmark)

    Jögi, I.; Erme, K.; Levoll, E.

    2017-01-01

    The removal of NOx from the exhaust gases requires the oxidation of most abundant NO to NO2 or N2O5. The oxidation can be done by non-thermal plasma but the efficiency is limited due to the back-reaction of NO2 to NO by O radicals. Present contribution investigates the role of catalysts in the im......The removal of NOx from the exhaust gases requires the oxidation of most abundant NO to NO2 or N2O5. The oxidation can be done by non-thermal plasma but the efficiency is limited due to the back-reaction of NO2 to NO by O radicals. Present contribution investigates the role of catalysts...... in the improvement of oxidation efficiency based on the stationary and time-dependent studies of the NOx oxidation at different reactor configurations and experimental conditions. The plasma produced active oxygen species (O, O3) were shown to play an important role in the reactions taking place on the catalyst...... surfaces while the exact mechanism and extent of the effect depended on the reactor configuration. The effect of catalyst at different experimental conditions was quantitatively described with the aid of analytical lumped kinetic models derived for the NOx oxidation when the catalyst was directly...

  13. Long-Term Synaptic Plasticity Emulated in Modified Graphene Oxide Electrolyte Gated IZO-Based Thin-Film Transistors.

    Science.gov (United States)

    Yang, Yi; Wen, Juan; Guo, Liqiang; Wan, Xiang; Du, Peifu; Feng, Ping; Shi, Yi; Wan, Qing

    2016-11-09

    Emulating neural behaviors at the synaptic level is of great significance for building neuromorphic computational systems and realizing artificial intelligence. Here, oxide-based electric double-layer (EDL) thin-film transistors were fabricated using 3-triethoxysilylpropylamine modified graphene oxide (KH550-GO) electrolyte as the gate dielectrics. Resulting from the EDL effect and electrochemical doping between mobile protons and the indium-zinc-oxide channel layer, long-term synaptic plasticity was emulated in our devices. Synaptic functions including long-term memory, synaptic temporal integration, and dynamic filters were successfully reproduced. In particular, spike rate-dependent plasticity (SRDP), one of the basic learning rules of long-term plasticity in the neural network where the synaptic weight changes according to the rate of presynaptic spikes, was emulated in our devices. Our results may facilitate the development of neuromorphic computational systems.

  14. Mechanism of growth, composition and structure of oxide films formed on ferrous alloys in molten salt electrolytes - a review

    International Nuclear Information System (INIS)

    Tzvetkoff, Tz.; Kolchakov, J.

    2004-01-01

    The growth kinetics, chemical composition and structure of scales formed during corrosion of Fe and its alloys in molten salts are reviewed. Special attention is paid to the effect of the composition of the molten salt mixture and the gas atmosphere on the stability and protective ability of corrosion layers. First, the thermodynamical background of the corrosion and oxidation of Fe-base engineering materials in molten salt media is briefly commented. A concise review of the growth kinetics of passivating oxide films is also presented. These two introductory chapters serve as a guide for the extensive survey of the growth mechanism, nature and properties of oxide and related scales on ferrous alloys in a range of molten electrolytes - chlorides, nitrates, sulphates, carbonates, hydroxides and mixtures thereof in gas atmospheres containing O 2 , CO 2 , SO 2 , SO 3 and HCl

  15. Ceramic solid electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Goodenough, John B. [Center for Materials Science and Engineering, University of Texas at Austin, Austin, TX (United States)

    1997-02-15

    Strategies for the design of ceramic solid electrolytes are reviewed. Problems associated with stoichiometric and doped compounds are compared. In the illustration of design principles, emphasis is given to oxide-ion electrolytes for use in solid-oxide fuel cells, oxygen pumps, and oxygen sensors

  16. Plasma diagnostics during magnetron sputtering of aluminum doped zinc oxide

    DEFF Research Database (Denmark)

    Stamate, Eugen; Crovetto, Andrea; Sanna, Simone

    2016-01-01

    Plasma parameters during magnetron sputtering of aluminum-doped zinc oxide are investigated with optical emission spectroscopy, electrostatic probes and mass spectrometry with the aim of understanding the role of negative ions of oxygen during the film growth and improving the uniformity of the f......Plasma parameters during magnetron sputtering of aluminum-doped zinc oxide are investigated with optical emission spectroscopy, electrostatic probes and mass spectrometry with the aim of understanding the role of negative ions of oxygen during the film growth and improving the uniformity...

  17. Detonation nanodiamond introduced into samarium doped ceria electrolyte improving performance of solid oxide fuel cell

    Science.gov (United States)

    Pei, Kai; Li, Hongdong; Zou, Guangtian; Yu, Richeng; Zhao, Haofei; Shen, Xi; Wang, Liying; Song, Yanpeng; Qiu, Dongchao

    2017-02-01

    A novel electrolyte materials of introducing detonation nanodiamond (DNDs) into samarium doped ceria (SDC) is reported here. 1%wt. DNDs doping SDC (named SDC/ND) can enlarge the electrotyle grain size and change the valence of partial ceria. DNDs provide the widen channel to accelerate the mobility of oxygen ions in electrolyte. Larger grain size means that oxygen ions move easier in electrolyte, it can also reduce the alternating current (AC) impedance spectra of internal grains. The lower valence of partial Ce provides more oxygen vacancies to enhance mobility rate of oxygen ions. Hence all of them enhance the transportation of oxygen ions in SDC/ND electrolyte and the OCV. Ultimately the power density of SOFC can reach 762 mw cm-2 at 800 °C (twice higher than pure SDC, which is 319 mw cm-2 at 800 °C), and it remains high power density in the intermediate temperature (600-800 °C). It is relatively high for the electrolyte supported (300 μm) cells.

  18. X-ray structural analysis of plasma sprayed europium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Gorshkov, B.N.; Loskutov, V.S.; Gavrish, A.A.; Shakh, G.E.

    1981-12-01

    An X-ray structure microanalysis is made for europium oxide powder produced by sintering and plasmic spheroidization for plasma spraying. The technique of concern is shown not to alter chemical composition of the powder. It is stated that a rise in the plasma jet enthalpy while spraying does not result in dissociation of europium oxide and its interaction with the plasma flux. The coating (to 15.2 kWxs/g) is found to have only a high-temperature (monoclinic) europium oxide phase and there appears a low-temperature (cubic) phase with a subsequent increase in the enthalpy. The plasma jet enthalpy increasing the grain size and the crystal lattice c parameter of the sprayed europium oxide are shown to decrease; the a parameter reduces with an enthalpy growth to 16.2 kW s/g and then smoothly increases with the enthalpy further growth. It is noticed that the europium oxide coating does not interact with an aluminium D16 alloy substrate.

  19. Effects of grain boundaries at the electrolyte/cathode interfaces on oxygen reduction reaction kinetics of solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Min Gi; Koo, Ja Yang; Ahn, Min Woo; Lee, Won Young [Dept. of Mechanical Engineering, Sungkyunkwan University, Suwon (Korea, Republic of)

    2017-04-15

    We systematically investigated the effects of grain boundaries (GBs) at the electrolyte/cathode interface of two conventional electrolyte materials, i.e., yttria-stabilized zirconia (YSZ) and gadolinia-doped ceria (GDC). We deposited additional layers by pulsed laser deposition to control the GB density on top of the polycrystalline substrates, obtaining significant improvements in peak power density (two-fold for YSZ and three-fold for GDC). The enhanced performance at high GB density in the additional layer could be ascribed to the accumulation of oxygen vacancies, which are known to be more active sites for oxygen reduction reactions (ORR) than grain cores. GDC exhibited a higher enhancement than YSZ, due to the easier formation, and thus higher concentration, of oxygen vacancies for ORR. The strong relation between the concentration of oxygen vacancies and the surface exchange characteristics substantiated the role of GBs at electrolyte/cathode interfaces on ORR kinetics, providing new design parameters for highly performing solid oxide fuel cells.

  20. Tuning thin-film electrolyte for lithium battery by grafting cyclic carbonate and combed poly(ethylene oxide) on polysiloxane.

    Science.gov (United States)

    Li, Jie; Lin, Yue; Yao, Hehua; Yuan, Changfu; Liu, Jin

    2014-07-01

    A tunable polysiloxane thin-film electrolyte for all-solid-state lithium-ion batteries was developed. The polysiloxane was synthesized by hydrosilylation of polymethylhydrosiloxane with cyclic [(allyloxy)methyl]ethylene ester carbonic acid and vinyl tris(2-methoxyethoxy)silane. (1) H NMR spectroscopy and gel-permeation chromatography demonstrated that the bifunctional groups of the cyclic propylene carbonate (PC) and combed poly(ethylene oxide) (PEO) were well grafted on the polysiloxane. At PC/PEO=6:4, the polysiloxane-based electrolyte had an ionic conductivity of 1.55 × 10(-4) and 1.50 × 10(-3)  S cm(-1) at 25 and 100 °C, respectively. The LiFePO4 /Li batteries fabricated with the thin-film electrolyte presented excellent cycling performance in the temperature range from 25 to 100 °C with an initial discharge capacity at a rate of 1 C of 88.2 and 140 mA h g(-1) at 25 and 100 °C, respectively. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Degradation of some ceria electrolytes under hydrogen contact nearby anode in solid oxide fuel cells (SOFCs

    Directory of Open Access Journals (Sweden)

    Malta Luiz Fernando Brum

    2004-01-01

    Full Text Available This work is concerned with thermodynamic analysis of the stability of some ceria electrolytes under contact with hydrogen gas nearby anode in fuel cells. It was considered the following types of ceria-electrolytes: pure ceria, strontium-doped ceria, calcium-doped ceria and calcium-bismuth-doped ceria. The equilibrium Log (pH2O/pH2 vs. T diagrams were constructed for x = 0.1 and 0.01, where x is the fraction of initial ceria converted to Ce2O3 (proportional to the ratio between activities of Ce3+ and Ce4+ in the ceria electrolyte, which is proportional to the fraction of electronic conduction in the electrolyte at a given temperature. The predictions of the diagrams are as follows: (a Ce1.9Ca0.1Bi0.8O5.1 and Ce0.9Sr0.1O1.9 are less stable than pure ceria for the whole temperature range (from 0 to 1000 °C; (b Ce0.9Ca0.1O1.9 is more stable than pure ceria below about 650 °C for x = 0.1 and below about 400 °C for x = 0.01; (c at each temperature in the considered range the pressure ratio pH2O(g/pH2(g has to be higher than thermodynamically predicted in order to keep CeO2 stable in the electrolyte contacting hydrogen gas. Thermodynamic predictions are entirely capable of explaining experimental data published on the subject (irreversible cell degradation in the case of SrO-doped ceria; weight loss from doped-ceria electrolyte above 700 °C; oxygen gas release during sintering of ceria.

  2. Ab initio investigation of ground-states and ionic motion in particular in zirconia-based solid-oxide electrolytes

    International Nuclear Information System (INIS)

    Hirschfeld, Julian Arndt

    2012-01-01

    Electrolytes with high ionic conductivity at lower temperatures are the prerequisite for the success of Solid Oxide Fuel Cells (SOFC). One candidate is doped zirconia. In the past, the electrical resistance of zirconia based SOFC electrolytes has mainly been decreased by reducing its thickness. But there are limits to reducing the thickness and one can say that nowadays the normal ways are basically exhausted to further enhance the conductivity of well-known electrolyte materials. Hence, new approaches need to be found to discover windows of enhanced ionic conductivity. This can be achieved by understanding the quantum-mechanical oxygen transport in unconventional configurations of doped zirconia. Therefore, such an understanding is of fundamental importance. In this thesis two approaches are pursued, the investigation of the strain dependent ionic migration in zirconia based electrolytes and the designing of an electrolyte material structure with enhanced and strongly anisotropic ionic conductivity. The first approach expands the elementary understanding of oxygen migration in oxide lattices. The migration barrier of the oxygen ion jumps in zirconia is determined by applying the Density Functional Theory (DFT) calculations in connection with the Nudged Elastic Band (NEB) method. These computations show an unexpected window of decreased migration barriers at high compressive strains. Similar to other publications a decrease in the migration barrier for expansive strain is observed. But, in addition, a migration barrier decrease under high compressive strains is found beyond a maximal height of the migration barrier. A simple analytic model offers an explanation. The drop of the migration barrier at high compressions originates from the elevation of the ground-state energy. This means: Increasing ground state energies becomes an interesting alternative to facilitate ionic mobility. The second approach is based on the idea, that actually, only in the direction of ion

  3. Ab initio investigation of ground-states and ionic motion in particular in zirconia-based solid-oxide electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Hirschfeld, Julian Arndt

    2012-12-11

    Electrolytes with high ionic conductivity at lower temperatures are the prerequisite for the success of Solid Oxide Fuel Cells (SOFC). One candidate is doped zirconia. In the past, the electrical resistance of zirconia based SOFC electrolytes has mainly been decreased by reducing its thickness. But there are limits to reducing the thickness and one can say that nowadays the normal ways are basically exhausted to further enhance the conductivity of well-known electrolyte materials. Hence, new approaches need to be found to discover windows of enhanced ionic conductivity. This can be achieved by understanding the quantum-mechanical oxygen transport in unconventional configurations of doped zirconia. Therefore, such an understanding is of fundamental importance. In this thesis two approaches are pursued, the investigation of the strain dependent ionic migration in zirconia based electrolytes and the designing of an electrolyte material structure with enhanced and strongly anisotropic ionic conductivity. The first approach expands the elementary understanding of oxygen migration in oxide lattices. The migration barrier of the oxygen ion jumps in zirconia is determined by applying the Density Functional Theory (DFT) calculations in connection with the Nudged Elastic Band (NEB) method. These computations show an unexpected window of decreased migration barriers at high compressive strains. Similar to other publications a decrease in the migration barrier for expansive strain is observed. But, in addition, a migration barrier decrease under high compressive strains is found beyond a maximal height of the migration barrier. A simple analytic model offers an explanation. The drop of the migration barrier at high compressions originates from the elevation of the ground-state energy. This means: Increasing ground state energies becomes an interesting alternative to facilitate ionic mobility. The second approach is based on the idea, that actually, only in the direction of ion

  4. Plasma metallization of aluminium oxide powder

    International Nuclear Information System (INIS)

    Smirnov, A.I.; Petrunichev, V.A.

    1981-01-01

    The sintering ability of cermets of metallized granulas of aluminium and matrix materials, such as chromium, nickel and nichrome is studied. Deformation tests of samples of cermets with molybdenum coated granules show satisfactory results at normal and high temperatures without fracture of metall-oxide interfaces [ru

  5. Effect of Zirconium Oxide Nanofiller and Dibutyl Phthalate Plasticizer on Ionic Conductivity and Optical Properties of Solid Polymer Electrolyte

    Science.gov (United States)

    Yasin, Siti Mariah Mohd; Ibrahim, Suriani

    2014-01-01

    New solid polymer electrolytes (SPE) based on poly(ethylene oxide) (PEO) doped with lithium trifluoromethanesulfonate (LiCF3SO3), dibutyl phthalate (DBP) plasticizer, and zirconium oxide (ZrO2) nanoparticles were prepared by solution-casting technique. The conductivity was enhanced by addition of dibutyl phthalate (DBP) plasticizer and ZrO2 nanofiller with maximum conductivity (1.38 × 10−4 Scm−1). The absorption edge and band gap values showed decreases upon addition of LiSO3CF3, DBP, and ZrO2 due to the formation of localized states in the SPE and the degree of disorder in the films increased. PMID:25133244

  6. Effect of Zirconium Oxide Nanofiller and Dibutyl Phthalate Plasticizer on Ionic Conductivity and Optical Properties of Solid Polymer Electrolyte

    Directory of Open Access Journals (Sweden)

    Siti Mariah Mohd Yasin

    2014-01-01

    Full Text Available New solid polymer electrolytes (SPE based on poly(ethylene oxide (PEO doped with lithium trifluoromethanesulfonate (LiCF3SO3, dibutyl phthalate (DBP plasticizer, and zirconium oxide (ZrO2 nanoparticles were prepared by solution-casting technique. The conductivity was enhanced by addition of dibutyl phthalate (DBP plasticizer and ZrO2 nanofiller with maximum conductivity (1.38×10-4 Scm-1. The absorption edge and band gap values showed decreases upon addition of LiSO3CF3, DBP, and ZrO2 due to the formation of localized states in the SPE and the degree of disorder in the films increased.

  7. Correlation of electrolyte-derived inclusions to crystallization in the early stage of anodic oxide film growth on titanium

    Energy Technology Data Exchange (ETDEWEB)

    Jaeggi, C., E-mail: christian.jaeggi@empa.ch [Empa, Swiss Federal Laboratories for Materials Testing and Research, Advanced Materials Processing Laboratory, Feuerwerkerstrasse 39, CH-3602 Thun (Switzerland); Parlinska-Wojtan, M., E-mail: magdalena.parlinska@empa.ch [Empa, Swiss Federal Laboratories for Materials Testing and Research, Center for Electron Microscopy, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland); Kern, P., E-mail: Philippe.Kern@neopac.ch [Empa, Swiss Federal Laboratories for Materials Testing and Research, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkerstrasse 39, CH-3602 Thun (Switzerland)

    2012-01-01

    Pure titanium has been subjected to anodization in sulfuric and phosphoric acid. For a better understanding of the oxide growth and properties of the final film, with a particular interest focused on the solution anions in the early stage of crystallization, microstructural analyses (Raman, Transmission Electron Microscopy [TEM]) of the oxide films were correlated to chemical depth profiling by glow discharge optical emission spectroscopy (GDOES). Raman spectroscopy shows that crystallization of the oxide films starts at potentials as low as 10-20 V. The onset of crystallization and the ongoing increase in crystallinity with increasing anodization potentials had already earlier been correlated to ac-impedance measurements [Jaeggi et al., Surf. Interface Anal. 38 (2006) 182]. TEM observations show a clear difference in the early phase of crystallization between oxides grown in 1 M sulfuric acid compared to 1 M phosphoric acid. Moreover, independent of electrolyte type, nano-sized pores from oxygen bubbles formation were revealed in the central part of the films. Until now, oxygen bubbles inside an anodically grown oxide have not been observed before without the presence of crystalline regions nearby. A growth model is proposed, in which the different starting locations of crystallization inside the films are correlated to the presence of the acid anions as residues in the film, as found by GDOES chemical depth-profiling.

  8. Kinetics of the electrolytic Fe+2/Fe+3 oxidation on various anode materials

    Directory of Open Access Journals (Sweden)

    Cifuentes, L.

    2003-08-01

    Full Text Available The kinetics of the electrolytic Fe+2/Fe+3 oxidation, relevant to hydro-electrometallurgical processing, have been studied on lead, platinum, ruthenium oxide, iridium oxide and graphite anodes in ferrous sulfate-sulfuric acid solutions. The oxidation rate depends on ferrous sulfate concentration, solution temperature and degree of agitation. Potentiodynamic studies show that: a the highest oxidation rate is obtained on platinum; b lead is unsuitable as anodic material for the said reaction; c the remaining anode materials show a similar and satisfactory performance.

    Se ha estudiado la cinética de la oxidación electrolítica Fe+2/Fe+3 -relevante para el procesamiento hidroelectrometalúrgico- sobre plomo, platino, óxido de rutenio, óxido de iridio y grafito en soluciones de sulfato ferroso en ácido sulfúrico. La velocidad de oxidación depende de la concentración de sulfato ferroso, la temperatura de la solución y el grado de agitación. Estudios potenciodinámicos demuestran que: a las mayores velocidades de oxidación se obtienen sobre platino; b el plomo es inadecuado como material anódico para la reacción mencionada; c los materiales anódicos restantes exhiben un desempeño similar y satisfactorio.

  9. Chemical compatibility of alternative perovskite oxide SOFC cathodes with doped lanthanum gallate solid electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Kostogloudis, G.C.; Ftikos, C. [Laboratory of Inorganic Materials Technology, Department of Chemical Engineering, National Technical University of Athens, 9 Heroon Polytechniou Str., Zografou Campus, GR-15780 Athens (Greece); Ahmad-Khanlou, A.; Naoumidis, A.; Stoever, D. [Research Centre Juelich, Institute for Materials and Processes in Energy Systems IWV1, D-52425 Juelich (Germany)

    2000-10-01

    This paper reports on the investigations of the chemical compatibility between SOFC cathode materials with compositions Pr{sub 0.8}Sr{sub 0.2}Co{sub 0.2}Mn{sub 0.8}O{sub 3-{delta}}, Pr{sub 0.8}Sr{sub 0.2}Co{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}}, Pr{sub 0.8}Sr{sub 0.2}Co{sub 0.3}Mn{sub 0.7}O{sub 3-{delta}} and Pr{sub 0.75}Sr{sub 0.2}Co{sub 0.2}Mn{sub 0.8}O{sub 3-{delta}} and the electrolyte materials with compositions La{sub 0.8}Sr{sub 0.2}Ga{sub 0.9}Mg{sub 0.1}O{sub 3-{delta}}, and La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 3-{delta}}. The lanthanum gallate electrolyte with 20 mol.% Sr contained two additional phases, namely, LaSrGa{sub 3}O{sub 7} and LaSrGaO{sub 4}, while that with 10 mol.% Sr was formed in nearly single phase. Two types of experiments were performed: (a) reactivity experiments of powder mixtures and (b) diffusion experiments in cathode/electrolyte double-layer pellets. No reaction products were detected by XRD. High Co diffusion into the electrolyte was identified with SEM/EDX in all diffusion experiments examined. The transition metals diffuse in the order Mnelectrolyte La{sub 0.8}Sr{sub 0.2}Ga{sub 0.9}Mg{sub 0.1}O{sub 3-{delta}} caused the destabilisation and disappearance of the second phases in the interdiffusion zone. In the case of the A-site deficient cathode, the formation of LaSrGa{sub 3}O{sub 7} second phase was identified on the electrolyte side, near the interdiffusion zone.

  10. Boron cross-linked graphene oxide/polyvinyl alcohol nanocomposite gel electrolyte for flexible solid-state electric double layer capacitor with high performance

    International Nuclear Information System (INIS)

    Huang, Yi-Fu; Wu, Peng-Fei; Zhang, Ming-Qiu; Ruan, Wen-Hong; Giannelis, Emmanuel P.

    2014-01-01

    Highlights: • Gel electrolyte is prepared and used in electric double layer capacitor. • Insertion of boron crosslinks into GO agglomerates opens channels for ion migration. • Solid supercapacitors show excellent specific capacitance and cycle stability. • Nanocomposite electrolyte shows better thermal stability and mechanical properties. - Abstract: A new family of boron cross-linked graphene oxide/polyvinyl alcohol (GO-B-PVA) nanocomposite gels is prepared by freeze-thaw/boron cross-linking method. Then the gel electrolytes saturated with KOH solution are assembled into electric double layer capacitors (EDLCs). Structure, thermal and mechanical properties of GO-B-PVA are explored. The electrochemical properties of EDLCs using GO-B-PVA/KOH are investigated, and compared with those using GO-PVA/KOH gel or KOH solution electrolyte. FTIR shows that boron cross-links are introduced into GO-PVA, while the boronic structure inserted into agglomerated GO sheets is demonstrated by DMA analysis. The synergy effect of the GO and the boron crosslinking benefits for ionic conductivity due to unblocking ion channels, and for improvement of thermal stability and mechanical properties of the electrolytes. Higher specific capacitance and better cycle stability of EDLCs are obtained by using the GO-B-PVA/KOH electrolyte, especially the one at higher GO content. The nanocomposite gel electrolytes with excellent electrochemical properties and solid-like character are candidates for the industrial application in high-performance flexible solid-state EDLCs

  11. Performance of Electrolyte Supported Solid Oxide Fuel Cells with STN Anodes

    DEFF Research Database (Denmark)

    Veltzé, Sune; Reddy Sudireddy, Bhaskar; Jørgensen, Peter Stanley

    2013-01-01

    In order to replace the state of the art Ni-cermet as SOFC anode, electrolyte supported cells comprising CGO/Ni infiltrated Nbdoped SrTiO3 anodes, and LSM/YSZ cathodes have been developed and tested as single 5 x 5 cm2 cells. The initial performance reached 0.4 W/cm2 at 850 C. Further tests under...

  12. Evidence for radical-oxidation of plasma proteins in humans

    International Nuclear Information System (INIS)

    Wang, D.; Davies, M.; Dean, R.; Fu, S.; Taurins, A.; Sullivans, D.

    1998-01-01

    Oxidation of proteins by radicals has been implicated in many pathological processes. The hydroxyl radical is known to generate protein-bound hydroxylated derivatives of amino acids, for example hydroxyvaline (from Val), hydroxyleucine (from Leu), o-tyrosine (from Phe), and DOPA (from Tyr). In this study, we have investigated the occurrence of these oxidised amino acids in human plasma proteins from both normal subjects and dialysis patients. By employing previously established HPLC methods [Fu et al. Biochemical Journal, 330, 233-239, 1998], we have found that oxidised amino acids exist in normal human plasma proteins (n=32). The level of these oxidised amino acids is not correlated to age. Similar levels of oxidised amino acids are found in the plasma proteins of the dialysis patients (n=6), but a more detailed survey is underway. The relative abundance of the oxidised amino acids is similar to that resulting from oxidation of BSA by hydroxy radicals or Fenton systems [Fu et al. Biochemical Journal, 333, 519-525, 1998]. The results suggest that metal-ion catalysed oxyl-radical chemistry may be a key contributor to the oxidative damage in plasma proteins in vivo in humans

  13. Characterization of low-temperature microwave loss of thin aluminum oxide formed by plasma oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Chunqing, E-mail: cdeng@uwaterloo.ca; Otto, M.; Lupascu, A., E-mail: alupascu@uwaterloo.ca [Institute for Quantum Computing, Department of Physics and Astronomy, and Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada)

    2014-01-27

    We report on the characterization of microwave loss of thin aluminum oxide films at low temperatures using superconducting lumped resonators. The oxide films are fabricated using plasma oxidation of aluminum and have a thickness of 5 nm. We measure the dielectric loss versus microwave power for resonators with frequencies in the GHz range at temperatures from 54 to 303 mK. The power and temperature dependence of the loss are consistent with the tunneling two-level system theory. These results are relevant to understanding decoherence in superconducting quantum devices. The obtained oxide films are thin and robust, making them suitable for capacitors in compact microwave resonators.

  14. Increased charge transfer of Poly (ethylene oxide) based electrolyte by addition of small molecule and its application in dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Muthuraaman, B.; Will, Geoffrey; Wang, Hongxia; Moonie, Paul; Bell, John

    2013-01-01

    A Poly (ethylene oxide) based polymer electrolyte impregnated with 2-Mercapto benzimidazole was comprehensively characterized by XRD, UV–visible spectroscopy, FTIR as well as electrochemical impedance spectroscopy. It was found that the crystallization of PEO was dramatically reduced and the ionic conductivity of the electrolyte was increased 4.5 fold by addition of 2-Mercapto benzimidazole. UV–visible and FTIR spectroscopes indicated the formation of charge transfer complex between 2-Mercapto benzimidazole and iodine of the electrolyte. Dye-sensitized solar cells with the polymer electrolytes were assembled. It was found that both the photocurrent density and photovoltage were enhanced with respect to the DSC without 2-Mercapto benzimidazole, leading to a 60% increase of the performance of the cell.

  15. Characteristics of an integrated cathode assembly for the electrolytic reduction of uranium oxide in a LiCl-Li2O molten salt

    International Nuclear Information System (INIS)

    Sung Bin Park; Byung Heung Park; Sang Mun Jeong; Jin Mok Hur; Chung Seok Seo; Seong Won Park; Seung-Hoon Choi

    2006-01-01

    Electrochemical behavior of the reduction of uranium oxide was studied in a LiCl-Li 2 O molten salt system with an integrated cathode assembly. The mechanism for the electrolytic reduction of uranium oxide was studied through cyclic voltammetry. By means of a chronopotentiometry, the effects of the thickness of the uranium oxide, the thickness of the MgO membrane and the material of the conductor of an integrated cathode assembly on the overpotential of the cathode were investigated. From the voltamograms, the reduction potential of the uranium oxide and Li 2 O was obtained and the two mechanisms of the electrolytic reduction were considered with regard to the applied cathode potential. From the chronopotentiograms, the exchange current, the transfer coefficient and the maximum allowable current based on the Tafel behavior were obtained with regard to the thickness of the uranium oxide, and of the MgO membrane and the material of the conductor of an integrated cathode assembly. (author)

  16. A study for an electrolytic reduction of tantalum oxide in a LiCl-Li2O molten salt

    International Nuclear Information System (INIS)

    Park, Sung Bin; Park, Byung Heung; Seo, Chung Seok; Kang, Dae Seung; Kwon, Seon Gil; Park, Seong Won

    2005-01-01

    Korea Atomic Energy Research Institute (KAERI) has developed the Advanced Spent Fuel Conditioning Process (ACP) to be an innovative technology for handling the PWR spent fuel. As part of ACP, the electrolytic reduction process (ER process) is the electrochemical reduction process of uranium oxide to uranium metal in a molten salt. The ER process has advantages in a technical stability, an economic potential and a good proliferation resistance. KAERI has reported on the good experimental results of an electrochemical reduction of the uranium oxide in a 20 kg HM/batch lab-scale. The ER process can be applicable to the reduction of other metal oxides. Metal tantalum powder has attracted attention for a variety of applications. A tantalum capacitor made from superfine and pliable tantalum powders is very small in size and it has a higher-capacitance part, therefore it is useful for microelectronic devices. By the ER process the metal tantalum can be obtained from tantalum pentoxide. In this work, a 40 g Ta 2 O 5 /batch electrochemical reactor was used for the synthesis of the metal tantalum. From the results of the cyclic voltammograms for the Ta 2 O 5 -LiCl-Li 2 O system, the mechanism of the tantalum reduction in a molten LiCl-Li 2 O salt system was investigated. Tantalum pentoxide is chemically reduced to tantalum metal by the lithium metal which is electrochemically deposited into an integrated cathode assembly in the LiCl-Li 2 O molten salt. The experiments for the tantalum reduction were performed with a chronopotentiometry in the reactor cell, the reduced products were analyzed from an analysis of the X-ray diffraction (XRD), scanning electron microscope and energy dispersive X-ray (SEM-EDX). From the results, the electrolytic reduction process is applicable to the synthesis of metal tantalum

  17. Oxidants and anti-oxidants in turbot seminal plasma and their effects on sperm quality

    Science.gov (United States)

    Han, Mingming; Ding, Fuhong; Meng, Zhen; Lei, Jilin

    2015-08-01

    In this research, the concentration and activity of oxidants and anti-oxidants in turbot semen, and their effects on sperm quality were studied. The results showed that superoxide dismutase (SOD), catalase, glutathione reductase (GR), uric acid, vitamin E (VE) and vitamin C (VC) were more abundant in seminal plasma than in spermatozoa. The variation for each of them was specific. In seminal plasma, the activity of SOD and GR increased from November 15, November 30 to December 15, and then decreased on December 30. The concentrations of both VC and uric acid decreased during the first 3 sampling times and increased on December 30. The oxidants in seminal plasma accumulated to the highest on December 30. Lactic acid (LA) and ATP levels decreased to the lowest on December 30. The correlation analysis showed that GR had the significant positive relevance to sperm motility and VSL/VCL, while ·OH had negative relevance to them.

  18. N-doped structures and surface functional groups of reduced graphene oxide and their effect on the electrochemical performance of supercapacitor with organic electrolyte

    Science.gov (United States)

    Li, Shin-Ming; Yang, Shin-Yi; Wang, Yu-Sheng; Tsai, Hsiu-Ping; Tien, Hsi-Wen; Hsiao, Sheng-Tsung; Liao, Wei-Hao; Chang, Chien-Liang; Ma, Chen-Chi M.; Hu, Chi-Chang

    2015-03-01

    Nitrogen-doped reduced graphene oxide (N-rGO) has been synthesized using a simple, efficient method combining instant thermal exfoliation and covalent bond transformation from a melamine-graphene oxide mixture. The capacitive performance of N-rGO has been tested in both aqueous (0.5 M H2SO4) and organic (1 M tetraethyl-ammonium tetrafluoroborate (TEABF4) in propylene carbonate (PC)) electrolytes, which are compared with those obtained from thermal-reduced graphene oxide (T-rGO) and chemical-reduced graphene oxide (C-rGO). The contributions of scan-rate-independent (double-layer-like) and scan-rate-dependent (pseudo-capacitance-like) capacitance of all reduced graphene oxides in both aqueous and organic electrolytes were evaluated and compared. The results show that relatively rich oxygen-containing functional groups on C-rGO form significant ion-diffusion barrier, resulting in worse electrochemical responses in organic electrolyte. By contrast, the N-doped structures, large surface area, and lower density of oxygen-containing groups make N-rGO become a promising electrode material for organic electric double-layer capacitors (EDLCs). The capacitance rate-retention of N-rGO reaches 71.1% in 1 M TEABF4/PC electrolyte when the scan rate is elevated to 200 mVs-1, demonstrating that N-rGO improves the relatively low-power drawback of EDLCs in organic electrolytes. The specific energy and power of a symmetric N-rGO cell in the organic electrolyte reach 25 Wh kg-1 and 10 kW kg-1, respectively.

  19. Advanced cathode materials for polymer electrolyte fuel cells based on pt/ metal oxides: from model electrodes to catalyst systems.

    Science.gov (United States)

    Fabbri, Emiliana; Pătru, Alexandra; Rabis, Annett; Kötz, Rüdiger; Schmidt, Thomas J

    2014-01-01

    The development of stable catalyst systems for application at the cathode side of polymer electrolyte fuel cells (PEFCs) requires the substitution of the state-of-the-art carbon supports with materials showing high corrosion resistance in a strongly oxidizing environment. Metal oxides in their highest oxidation state can represent viable support materials for the next generation PEFC cathodes. In the present work a multilevel approach has been adopted to investigate the kinetics and the activity of Pt nanoparticles supported on SnO2-based metal oxides. Particularly, model electrodes made of SnO2 thin films supporting Pt nanoparticles, and porous catalyst systems made of Pt nanoparticles supported on Sb-doped SnO2 high surface area powders have been investigated. The present results indicate that SnO2-based supports do not modify the oxygen reduction reaction mechanism on the Pt nanoparticle surface, but rather lead to catalysts with enhanced specific activity compared to Pt/carbon systems. Different reasons for the enhancement in the specific activity are considered and discussed.

  20. Development and testing of anode-supported solid oxide fuel cells with slurry-coated electrolyte and cathode

    Energy Technology Data Exchange (ETDEWEB)

    Muccillo, R.; Muccillo, E.N.S.; Fonseca, F.C.; Franca, Y.V.; Porfirio, T.C. [Centro de Ciencia e Tecnologia de Materiais, Instituto de Pesquisas Energeticas e Nucleares, C.P. 11049, Pinheiros, S. Paulo, SP 05422-970 (Brazil); de Florio, D.Z. [Instituto de Quimica, UNESP, R. Prof. Francisco Degni s/n, Araraquara, SP 14801-970 (Brazil); Berton, M.A.C.; Garcia, C.M. [Instituto de Tecnologia para o Desenvolvimento, DPMA, C.P. 19067, Curitiba, PR 81531-980 (Brazil)

    2006-06-01

    A laboratory setup was designed and put into operation for the development of solid oxide fuel cells (SOFCs). The whole project consisted of the preparation of the component materials: anode, cathode and electrolyte, and the buildup of a hydrogen leaking-free sample chamber with platinum leads and current collectors for measuring the electrochemical properties of single SOFCs. Several anode-supported single SOFCs of the type (ZrO{sub 2}:Y{sub 2}O{sub 3}+NiO) thick anode/(ZrO{sub 2}:Y{sub 2}O{sub 3}) thin electrolyte/(La{sub 0.65}Sr{sub 0.35}MnO{sub 3}+ZrO{sub 2}:Y{sub 2}O{sub 3}) thin cathode have been prepared and tested at 700 and 800{sup o}C after in situ H{sub 2} anode reduction. The main results show that the slurry-coating method resulted in single-cells with good reproducibility and reasonable performance, suggesting that this method can be considered for fabrication of SOFCs. (author)

  1. Minimization of Ion-Solvent Clusters in Gel Electrolytes Containing Graphene Oxide Quantum Dots for Lithium-Ion Batteries.

    Science.gov (United States)

    Chen, Yen-Ming; Hsu, Shih-Ting; Tseng, Yu-Hsien; Yeh, Te-Fu; Hou, Sheng-Shu; Jan, Jeng-Shiung; Lee, Yuh-Lang; Teng, Hsisheng

    2018-03-01

    This study uses graphene oxide quantum dots (GOQDs) to enhance the Li + -ion mobility of a gel polymer electrolyte (GPE) for lithium-ion batteries (LIBs). The GPE comprises a framework of poly(acrylonitrile-co-vinylacetate) blended with poly(methyl methacrylate) and a salt LiPF 6 solvated in carbonate solvents. The GOQDs, which function as acceptors, are small (3-11 nm) and well dispersed in the polymer framework. The GOQDs suppress the formation of ion-solvent clusters and immobilize PF6- anions, affording the GPE a high ionic conductivity and a high Li + -ion transference number (0.77). When assembled into Li|electrolyte|LiFePO 4 batteries, the GPEs containing GOQDs preserve the battery capacity at high rates (up to 20 C) and exhibit 100% capacity retention after 500 charge-discharge cycles. Smaller GOQDs are more effective in GPE performance enhancement because of the higher dispersion of QDs. The minimization of both the ion-solvent clusters and degree of Li + -ion solvation in the GPEs with GOQDs results in even plating and stripping of the Li-metal anode; therefore, Li dendrite formation is suppressed during battery operation. This study demonstrates a strategy of using small GOQDs with tunable properties to effectively modulate ion-solvent coordination in GPEs and thus improve the performance and lifespan of LIBs. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. A novel method for the preparation of uranium metal, oxide and carbide via electrolytic amalgamation

    International Nuclear Information System (INIS)

    Wang, L.C.; Lee, H.C.; Lee, T.S.; Lai, W.C.; Chang, C.T.

    1978-01-01

    A solid uranium amalgam was prepared electrolytically using a two-compartment cell separated with an ion exchange membrane for the purpose of regulating pH value within a narrowly restricted region of 2 to 3. The mercury cathode was kept at -1.8V vs SCE during electrolysis. The thereby obtained amalgam containing as high as 1.9gm U/ml Hg is easily converted into uranium metal by heating in vacuo above 1300 0 C. Uranium dioxide and uranium monocarbide could be easily obtained at relatively low temperature by reacting the amalgam with water vapor and methane. (author)

  3. Differential plasma protein binding to metal oxide nanoparticles

    International Nuclear Information System (INIS)

    Deng, Zhou J; Mortimer, Gysell; Minchin, Rodney F; Schiller, Tara; Musumeci, Anthony; Martin, Darren

    2009-01-01

    Nanoparticles rapidly interact with the proteins present in biological fluids, such as blood. The proteins that are adsorbed onto the surface potentially dictate the biokinetics of the nanomaterials and their fate in vivo. Using nanoparticles with different sizes and surface characteristics, studies have reported the effects of physicochemical properties on the composition of adsorbed plasma proteins. However, to date, few studies have been conducted focusing on the nanoparticles that are commonly exposed to the general public, such as the metal oxides. Using previously established ultracentrifugation approaches, two-dimensional gel electrophoresis and mass spectrometry, the current study investigated the binding of human plasma proteins to commercially available titanium dioxide, silicon dioxide and zinc oxide nanoparticles. We found that, despite these particles having similar surface charges in buffer, they bound different plasma proteins. For TiO 2 , the shape of the nanoparticles was also an important determinant of protein binding. Agglomeration in water was observed for all of the nanoparticles and both TiO 2 and ZnO further agglomerated in biological media. This led to an increase in the amount and number of different proteins bound to these nanoparticles. Proteins with important biological functions were identified, including immunoglobulins, lipoproteins, acute-phase proteins and proteins involved in complement pathways and coagulation. These results provide important insights into which human plasma proteins bind to particular metal oxide nanoparticles. Because protein absorption to nanoparticles may determine their interaction with cells and tissues in vivo, understanding how and why plasma proteins are adsorbed to these particles may be important for understanding their biological responses.

  4. Air trichloroethylene oxidation in a corona plasma-catalytic reactor

    International Nuclear Information System (INIS)

    Masoomi-Godarzi, S.; Ranji-Burachaloo, H.; Khodadadi, A.A.; Vesali-Naseh, M.; Mortazavi, Y.

    2014-01-01

    The oxidative decomposition of trichloroethylene (TCE; 300 ppm) by non-thermal corona plasma was investigated in dry air at atmospheric pressure and room temperature, both in the absence and presence of catalysts including MnO x , CoO x . The catalysts were synthesized by a co-precipitation method. The morphology and structure of the catalysts were characterized by BET surface area measurement and Fourier Transform Infrared (FTIR) methods. Decomposition of TCE and distribution of products were evaluated by a gas chromatograph (GC) and an FTIR. In the absence of the catalyst, TCE removal is increased with increases in the applied voltage and current intensity. Higher TCE removal and CO 2 selectivity is observed in presence of the corona and catalysts, as compared to those with the plasma alone. The results show that MnO x and CoO x catalysts can dissociate the in-plasma produced ozone to oxygen radicals, which enhances the TCE decomposition. (author)

  5. Air trichloroethylene oxidation in a corona plasma-catalytic reactor

    Science.gov (United States)

    Masoomi-Godarzi, S.; Ranji-Burachaloo, H.; Khodadadi, A. A.; Vesali-Naseh, M.; Mortazavi, Y.

    2014-08-01

    The oxidative decomposition of trichloroethylene (TCE; 300 ppm) by non-thermal corona plasma was investigated in dry air at atmospheric pressure and room temperature, both in the absence and presence of catalysts including MnOx, CoOx. The catalysts were synthesized by a co-precipitation method. The morphology and structure of the catalysts were characterized by BET surface area measurement and Fourier Transform Infrared (FTIR) methods. Decomposition of TCE and distribution of products were evaluated by a gas chromatograph (GC) and an FTIR. In the absence of the catalyst, TCE removal is increased with increases in the applied voltage and current intensity. Higher TCE removal and CO2 selectivity is observed in presence of the corona and catalysts, as compared to those with the plasma alone. The results show that MnOx and CoOx catalysts can dissociate the in-plasma produced ozone to oxygen radicals, which enhances the TCE decomposition.

  6. Study of thermal and electrical parameters of workpieces during spray coating by electrolytic plasma jet

    International Nuclear Information System (INIS)

    Khafizov, A A; Shakirov, Yu I; Valiev, R A; Valiev, R I; Khafizova, G M

    2016-01-01

    In this paper the results are presented of thermal and electrical parameters of products in the system bottom layer - intermediate layer when applying protective coatings of ferromagnetic powder by plasma spray produced in an electric discharge with a liquid cathode, on steel samples. Temperature distribution and gradients in coating and intermediate coating were examined. Detailed descriptions of spray coating with ferromagnetic powder by plasma jet obtained in electrical discharge with liquid cathode and the apparatus for obtaining thereof is provided. Problem has been solved by using of Fourier analysis. Initial data for calculations is provided. Results of numerical analysis are provided as temporal functions of temperature in contiguity between coating and intermediate coating as well as temporal function of the value Q=q-φ; where q is density of heat current directed to the free surface of intermediate coating, φ is density of heat current in contiguity between coating and intermediate coating. The analysis of data given shows that in the systems of contact heat exchange bottom layer-intermediate layer with close values of the thermophysical characteristics of constituting materials is observed a slow increase of the temperature of the contact as a function of time. (paper)

  7. Electrochromic Ni–Fe oxide thin films synthesized by an atmospheric pressure plasma jet for flexible electrochromic application

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Yun-Sen, E-mail: yslin@fcu.edu.tw; Chuang, Pei-Ying; Shie, Ping-Shiun

    2014-11-03

    Flexible-electrochromic organo-nickel-iron oxide (NiFe{sub x}O{sub y}C{sub z}) films deposited onto flexible polyethylene terephthalate (PET)/indium tin oxide (ITO) substrates using atmospheric-pressure plasma-enhanced chemical vapor deposition with an atmospheric pressure plasma jet under various flow rates of oxygen gases are investigated. Precursors [nickelocence, Ni(C{sub 5}H{sub 5}){sub 2}] and [ferrocence, Fe(C{sub 5}H{sub 5}){sub 2}] vapors are carried by argon gas, mixed by oxygen gas and injected into air plasma torch for a rapid synthesis of NiFe{sub x}O{sub y}C{sub z} films by a short duration of the substrate, 32 s, in the plasmas. Uniform light modulation on PET/ITO/NiFe{sub x}O{sub y}C{sub z} is produced while the moving PET/ITO substrate is exposed to plasma torch at room temperature (∼ 23 °C) and atmospheric pressure. Light modulation with up to a 43.2% transmittance variation at a wavelength of 708 nm even after 200 cycles of Li{sup +} intercalation and de-intercalation in a 1 M LiClO{sub 4}-propylene carbonate electrolyte is accomplished. - Highlights: • Rapid deposition of electrochromic organo-nickel–iron oxide (NiFe{sub x}O{sub y}C{sub z}) films • Enhanced electrochromic performance of NiFe{sub x}O{sub y}C{sub z} films by oxygen gas addition • Uniform light modulation on NiFe{sub x}O{sub y}C{sub z} films produced by air plasma jet • Porous surfaces allow reversible Li{sup +} intercalation and deintercalation.

  8. Optical and electrical experiments at some transition-metal oxide foil-electrolyte interfaces

    International Nuclear Information System (INIS)

    Sari, S.O.; Ahlgren, W.L.

    1977-01-01

    Metal-oxide layers formed from transition-metal foils oxidized by heating in air have been examined for their photoelectrolytic response. The metals examined are Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, and Pt. Weak photoeffects are observed for oxide layers of all of these metals. Sizable light-dependent oxygen gas evolution rates are found in Ti and also in W oxides. The spectral dependence of the oxygen response in these compounds is investigated, and interpretation is given of these experiments

  9. Mesomorphic structure of poly(styrene)-block-poly(4-vinylpyridine) with oligo(ethylene oxide)sulfonic acid side chains as a model for molecularly reinforced polymer electrolyte

    NARCIS (Netherlands)

    Kosonen, H; Valkama, S; Hartikainen, J; Eerikainen, H; Torkkeli, M; Jokela, K; Serimaa, R; Sundholm, F; ten Brinke, G; Ikkala, O; Eerikäinen, Hannele

    2002-01-01

    We report self-organized polymer electrolytes based on poly(styrene)-block-poly(4-vinylpyridine) (PS-block-P4VP). Liquidlike ethylene oxide (EO) oligomers with sulfonic acid end groups are bonded to the P4VP block, leading to comb-shaped supramolecules with the PS-block-P4VP backbone. Lithium

  10. Y-doped BaZrO3 as a chemically stable electrolyte for proton-conducting solid oxide electrolysis cells (SOECs)

    KAUST Repository

    Bi, Lei

    2015-01-01

    A proton-conducting solid oxide electrolysis cell using an Y-doped BaZrO3 electrolyte film, which has been demonstrated to be chemically stable, was successfully fabricated for the first time and showed a promising electrolysis performance.

  11. Steam Electrolysis by Proton-Conducting Solid Oxide Electrolysis Cells (SOECs) with Chemically Stable BaZrO3-Based Electrolytes

    KAUST Repository

    Bi, Lei; Traversa, Enrico

    2015-01-01

    BaZrO3-based material was applied as the electrolyte for proton-conducting solid oxide fuel cells (SOECs). Compared with the instability of BaCeO3-based proton-conductors, BaZrO3-based material could be a more promising candidate for proton

  12. In operando studies of ScYSZ electrolyte supported symmetric solid oxide cell by X-ray Diffraction at ESRF, ID06 Beamline

    DEFF Research Database (Denmark)

    Sierra, J. X.; Poulsen, H. F.; Jørgensen, P. S.

    Solid Oxide Cells are becoming a promising solution for sustainable and renewable power generation. Scandium doped Yttria Stabilized Zirconia is considered one of the best materials used as electrolyte because of its high ionic conductivity and great mechanical and chemical stability under operat...... evolution at different depths of the cell during operation....

  13. Electrocatalytic activity and operational stability of electrodeposited Pd-Co films towards ethanol oxidation in alkaline electrolytes

    Science.gov (United States)

    Tsui, Lok-kun; Zafferoni, Claudio; Lavacchi, Alessandro; Innocenti, Massimo; Vizza, Francesco; Zangari, Giovanni

    2015-10-01

    Direct alkaline ethanol fuel cells (DEFCs) are usually run with Pd anodic catalysts, but their performance can be improved by utilizing alloys of Pd and Co. The oxyphilic Co serves to supply ample -OH to the ethanol oxidation reaction, accelerating the rate limiting step at low overpotential under alkaline conditions. Pd-Co films with compositions between 20 and 80 at% Co can be prepared by electrodeposition from a NH3 complexing electrolyte. Cyclic voltammetry studies show that the ethanol oxidation peak exhibits increasing current density with increasing Co content, reaching a maximum at 77% Co. In contrast, potentiostatic measurements under conditions closer to fuel cell operating conditions show that a 50 at% Co alloy has the highest performance. Importantly, the Co-Pd film is also found to undergo phase and morphological transformations during ethanol oxidation, resulting in a change from a compact film to high surface area flake-like structures containing Co3O4 and CoOOH; such a transformation instead is not observed when operating at a constant potential of 0.7 VRHE.

  14. Electrode-Impregnable and Cross-Linkable Poly(ethylene oxide)-Poly(propylene oxide)-Poly(ethylene oxide) Triblock Polymer Electrolytes with High Ionic Conductivity and a Large Voltage Window for Flexible Solid-State Supercapacitors.

    Science.gov (United States)

    Han, Jae Hee; Lee, Jang Yong; Suh, Dong Hack; Hong, Young Taik; Kim, Tae-Ho

    2017-10-04

    We present cross-linkable precursor-type gel polymer electrolytes (GPEs) that have large ionic liquid uptake capability, can easily penetrate electrodes, have high ion conductivity, and are mechanically strong as high-performance, flexible all-solid-state supercapacitors (SC). Our polymer precursors feature a hydrophilic-hydrophobic poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock main-chain structure and trifunctional silane end groups that can be multi-cross-linked with each other through a sol-gel process. The cross-linked solid-state electrolyte film with moderate IL content (200 wt %) shows a well-balanced combination of excellent ionic conductivity (5.0 × 10 -3 S cm -1 ) and good mechanical stability (maximum strain = 194%). Moreover, our polymer electrolytes have various advantages including high thermal stability (decomposition temperature > 330 °C) and the capability to impregnate electrodes to form an excellent electrode-electrolyte interface due to the very low viscosity of the precursors. By assembling our GPE-impregnated electrodes and solid-state GPE film, we demonstrate an all-solid-state SC that can operate at 3 V and provides an improved specific capacitance (112.3 F g -1 at 0.1 A g -1 ), better rate capability (64% capacity retention until 20 A g -1 ), and excellent cycle stability (95% capacitance decay over 10 000 charge/discharge cycles) compared with those of a reference SC using a conventional PEO electrolyte. Finally, flexible SCs with a high energy density (22.6 W h kg -1 at 1 A g -1 ) and an excellent flexibility (>93% capacitance retention after 5000 bending cycles) can successfully be obtained.

  15. Determination of thermodynamic properties and stability limit from fluorite phase of uranium and lanthanide mixed oxides, using galvanic cells with solid electrolytes

    International Nuclear Information System (INIS)

    Santiago, T.N.

    1980-10-01

    A method for thermodynamic properties determination for oxygen solubility in oxide systems at temperature interval 973 ≤ T [K] ≤ 1773 is described. A galvanic cell using as solid electrolytes zircon dioxide doped with 15% of calcium oxide is presented. This method was used for determining the phase change, temperature dependent, of uranium-lanthanides-oxygen Ln U O 4 stoichiometric system. (C.G.C.)

  16. Hydrogenation of gold-related levels in silicon by electrolytic doping

    International Nuclear Information System (INIS)

    Pearton, S.J.; Hansen, W.L.; Haller, E.E.; Kahn, J.M.

    1984-01-01

    The deep gold-related donor and acceptor levels in silicon have been neutralized to several μm depth by introducing atomic hydrogen using an electrolytic method. Using phosphoric or sulfuric acid as the electrolyte, it is possible to dope the crystalline silicon with hydrogen at elevated temperatures (200--280 0 C) allowing direct comparison with other means of introduction, such as hydrogen plasma exposure. We find the electrolytic method is not as efficient as plasma treatment for the same conditions, possibly due to oxide formation during the immersion in the acid

  17. The oxidation of organic additives in the positive vanadium electrolyte and its effect on the performance of vanadium redox flow battery

    Science.gov (United States)

    Nguyen, Tam D.; Whitehead, Adam; Scherer, Günther G.; Wai, Nyunt; Oo, Moe O.; Bhattarai, Arjun; Chandra, Ghimire P.; Xu, Zhichuan J.

    2016-12-01

    Despite many desirable properties, the vanadium redox flow battery is limited, in the maximum operation temperature that can be continuously endured, before precipitation begins in the positive electrolyte. Many additives have been proposed to improve the thermal stability of the charged positive electrolyte. However, we have found that the apparent stability, revealed in laboratory testing, is often simply an artifact of the test method and arises from the oxidation of the additive, with corresponding partial reduction of V(V) to V(IV). This does not improve the stability of the electrolyte in an operating system. Here, we examined the oxidation of some typical organic additives with carboxyl, alcohol, and multi-functional groups, in sulfuric acid solutions containing V(V). The UV-vis measurements and titration results showed that many compounds reduced the state-of-charge (SOC) of vanadium electrolyte, for example, by 27.8, 88.5, and 81.9% with the addition of 1%wt of EDTA disodium salt, pyrogallol, and ascorbic acid, respectively. The cell cycling also indicated the effect of organic additives on the cell performance, with significant reduction in the usable charge capacity. In addition, a standard screening method for thermally stable additives was introduced, to quickly screen suitable additives for the positive vanadium electrolyte.

  18. Challenge of non-precious metal oxide-based cathode for polymer electrolyte fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Ishihara, Akimitsu; Matsuzawa, Koichi; Mitsushima, Shigenori; Ota, Ken-ichiro [Yokohama National Univ. (Japan)

    2010-07-01

    The partially oxidized TaC{sub 0.58}N{sub 0.42} was investigated as non-platinum cathode for PEFC. In order to quantify the degree of oxidation, the degree of oxidation (DOO) was defined using the XRD peaks of Ta-CN and Ta{sub 2}O{sub 5}. The onset potential for the oxidation reduction reaction (ORR) had high value, that is, 0.9 V vs. RHE (reversible hydrogen electrode), at higher oxidation state of the TaC{sub 0.58}N{sub 0.42}. We found that the partial oxidation of TaC{sub 0.58}N{sub 0.42} was greatly useful to enhance the catalytic activity for the ORR. The volcano plot of the ionization potential vs. the E{sub ORR} suggested that there was a suitable interaction between the surface of the partially oxidized TaC{sub 0.58}N{sub 0.42} and oxygen. (orig.)

  19. Inhibition of Direct Electrolytic Ammonia Oxidation Due to a Change in Local pH

    International Nuclear Information System (INIS)

    Zöllig, Hanspeter; Morgenroth, Eberhard; Udert, Kai M.

    2015-01-01

    Electrochemical ammonia oxidation has gained a lot of attention recently as an efficient method for ammonia removal from wastewater, for the use in ammonia-based fuel cells and the production of high purity hydrogen. Thermally decomposed iridium oxide films (TDIROF) have been shown to be catalytically active for direct ammonia oxidation in aqueous solutions if NH 3 is present. However, the process was reported to be rapidly inhibited on TDIROF. Herein, we show that this fast inhibition of direct ammonia oxidation does not result from surface poisoning by adsorbed elemental nitrogen (N ads ). Instead, we propose that direct ammonia oxidation and oxygen evolution can lead to a drop of the local pH at the electrode resulting in a low availability of the actual reactant, NH 3 . The hypothesis was tested with cyclic voltammetry (CV) experiments on stagnant and rotating disk electrodes (RDE). The CV experiments on the stagnant electrode revealed that the decrease of the ammonia oxidation peaks was considerably reduced by introducing an idle phase at open circuit potential between subsequent scans. Furthermore, the polarization of the TDIROF electrode into the hydrogen evolution region (HER) resulted in increased ammonia oxidation peaks in the following anodic scans which can be explained with an increased local pH after the consumption of protons in the HER. On the RDE, the ammonia oxidation peaks did not decrease in immediately consecutive scans. These findings would not be expected if surface poisoning was responsible for the fast inhibition but they are in good agreement with the proposed mechanism of pH induced limitation by the reactant, NH 3 . The plausibility of the mechanism was also supported by our numerical simulations of the processes in the Nernstian diffusion layer. The knowledge about this inhibition mechanism of direct ammonia oxidation is especially important for the design of electrochemical cells for wastewater treatment. The mechanism is not only

  20. A chemically stable electrolyte with a novel sandwiched structure for proton-conducting solid oxide fuel cells (SOFCs)

    KAUST Repository

    Bi, Lei; Traversa, Enrico

    2013-01-01

    A chemically stable electrolyte structure was developed for proton-conducting SOFCs by using two layers of stable BaZr0.7Pr 0.1Y0.2O3 -δ to sandwich a highly-conductive but unstable BaCe0.8Y0.2O 3 -δ electrolyte layer. The sandwiched electrolyte

  1. Air plasma spray processing and electrochemical characterization of Cu-SDC coatings for use in solid oxide fuel cell anodes

    Energy Technology Data Exchange (ETDEWEB)

    Benoved, Nir [Department of Mechanical Engineering, The University of British Columbia, 2054-6250 Applied Sciences Lane, Vancouver, British Columbia (Canada); Kesler, O. [Department of Mechanical and Industrial Engineering, University of Toronto, 5 King' s College Road, Toronto, Ontario (Canada)

    2009-09-05

    Air plasma spraying has been used to produce porous composite anodes based on Ce{sub 0.8}Sm{sub 0.2}O{sub 1.9} (SDC) and Cu for use in solid oxide fuel cells (SOFCs). Preliminarily, a range of plasma conditions has been examined for the production of composite coatings from pre-mixed SDC and CuO powders. Plasma gas compositions were varied to obtain a range of plasma temperatures. After reduction in H{sub 2}, coatings were characterized for composition and microstructure using EDX and SEM. As a result of these tests, symmetrical sintered electrolyte-supported anode-anode cells were fabricated by air plasma spraying of the anodes, followed by in situ reduction of the CuO to Cu. Full cells deposited on SS430 porous substrates were then produced in one integrated process. Fine CuO and SDC powders have been used to produce homogeneously mixed anode coatings with higher surface area microstructures, resulting in area-specific polarization resistances of 4.8 {omega} cm{sup 2} in impedance tests in hydrogen at 712 C. (author)

  2. Air plasma spray processing and electrochemical characterization of Cu-SDC coatings for use in solid oxide fuel cell anodes

    Science.gov (United States)

    Benoved, Nir; Kesler, O.

    Air plasma spraying has been used to produce porous composite anodes based on Ce 0.8Sm 0.2O 1.9 (SDC) and Cu for use in solid oxide fuel cells (SOFCs). Preliminarily, a range of plasma conditions has been examined for the production of composite coatings from pre-mixed SDC and CuO powders. Plasma gas compositions were varied to obtain a range of plasma temperatures. After reduction in H 2, coatings were characterized for composition and microstructure using EDX and SEM. As a result of these tests, symmetrical sintered electrolyte-supported anode-anode cells were fabricated by air plasma spraying of the anodes, followed by in situ reduction of the CuO to Cu. Full cells deposited on SS430 porous substrates were then produced in one integrated process. Fine CuO and SDC powders have been used to produce homogeneously mixed anode coatings with higher surface area microstructures, resulting in area-specific polarization resistances of 4.8 Ω cm 2 in impedance tests in hydrogen at 712 °C.

  3. Bilayer electrolyte-anode for solid oxide fuel cell; Obtencao de bicamadas eletrolito-anodo para pilhas a combustivel de oxido solido

    Energy Technology Data Exchange (ETDEWEB)

    Crochemore, G.B.; Marcomini, R.F.; Souza, D.P.F. de [Universidade Federal de Sao Carlos (GEMM/UFSCAR), Sao Carlos, SP (Brazil). Programa de Pos Graduacao em Ciencia e Engenharia de Materiais], Email: dulcina@ufscar.br; Rabelo, A.A. [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Fac. de Engenharia de Materiais

    2010-07-01

    Solid oxide fuel cell is a high efficient device hence it plays a very important role in the hydrogen economy. However, the cell operation temperature must be lower than 800 deg C, what is attainable for thin Yttria stabilized zirconia (YSZ) electrolytes. The tape casting process is the most used technique because it allows a very fine tuning of the tape thickness. In this work it were investigated the processing conditions for obtaining electrolyte-anode (YSZ/ YSZ-NiO) bilayers with no lamination after the sintering process. (author)

  4. Kinetics of sodium borohydride direct oxidation and oxygen reduction in sodium hydroxide electrolyte

    International Nuclear Information System (INIS)

    Chatenet, Marian; Micoud, Fabrice; Roche, Ivan; Chainet, Eric

    2006-01-01

    The direct oxidation of sodium borohydride in concentrated sodium hydroxide medium has been studied by cyclic and linear voltammetry, chronoamperometry and chronopotentiometry for silver and gold electrocatalysts, either bulk and polycrystalline or nanodispersed over high area carbon blacks. Gold and silver yield rather complete utilisation of the reducer: around 7.5 electrons are delivered on these materials, versus 4 at the most for platinum as a result of the BH 4 - non-negligible hydrolysis taking place on this latter material. The kinetic parameters for the direct borohydride oxidation are better for gold than for silver. A strong influence of the ratio of sodium hydroxide versus sodium borohydride is found: whereas the theoretical stoichiometry does forecast that eight hydroxide ions are needed for each borohydride ion, our experimental results prove that a larger excess hydroxide ion is necessary in quasi-steady state conditions. When the above-mentioned ratio is unity (1 M NaOH and 1 M NaBH 4 ), the tetrahydroborate ions direct oxidation is limited by the hydroxide concentration, and their hydrolysis is no longer negligible. The hydrolysis products are probably BH 3 OH - ions, for which gold displays a rather good oxidation activity. Additionally, silver, which is a weak BH 4 - oxidation electrocatalyst, exhibits the best activity of all the studied materials towards the BH 3 OH - direct oxidation. Finally, carbon-supported gold nanoparticles seem promising as anode material to be used in direct borohydride fuel cells

  5. Chemical compatibility and properties of suspension plasma-sprayed SrTiO3-based anodes for intermediate-temperature solid oxide fuel cells

    Science.gov (United States)

    Zhang, Shan-Lin; Li, Cheng-Xin; Li, Chang-Jiu

    2014-10-01

    La-doped strontium titanate (LST) is a promising, redox-stable perovskite material for direct hydrocarbon oxidation anodes in intermediate-temperature solid oxide fuel cells (IT-SOFCs). In this study, nano-sized LST and Sm-doped ceria (SDC) powders are produced by the sol-gel and glycine-nitrate processes, respectively. The chemical compatibility between LST and electrolyte materials is studied. A LST-SDC composite anode is prepared by suspension plasma spraying (SPS). The effects of annealing conditions on the phase structure, microstructure, and chemical stability of the LST-SDC composite anode are investigated. The results indicate that the suspension plasma-sprayed LST-SDC anode has the same phase structure as the original powders. LST exhibits a good chemical compatibility with SDC and Mg/Sr-doped lanthanum gallate (LSGM). The anode has a porosity of ∼40% with a finely porous structure that provides high gas permeability and a long three-phase boundary for the anode reaction. Single cells assembled with the LST-SDC anode, La0.8Sr0.2Ga0.8Mg0.2O3 electrolyte, and La0.8Sr0.2CoO3-SDC cathode show a good performance at 650-800 °C. The annealing reduces the impedances due to the enhancement in the bonding between the particles in the anode and interface of anode and LSGM electrolyte, thus improving the output performance of the cell.

  6. A chemically stable electrolyte with a novel sandwiched structure for proton-conducting solid oxide fuel cells (SOFCs)

    KAUST Repository

    Bi, Lei

    2013-11-01

    A chemically stable electrolyte structure was developed for proton-conducting SOFCs by using two layers of stable BaZr0.7Pr 0.1Y0.2O3 -δ to sandwich a highly-conductive but unstable BaCe0.8Y0.2O 3 -δ electrolyte layer. The sandwiched electrolyte structure showed good chemical stability in both CO2 and H2O atmosphere, indicating that the BZPY layers effectively protect the inner BCY electrolyte, while the BCY electrolyte alone decomposed completely under the same conditions. Fuel cell prototypes fabricated with the sandwiched electrolyte achieved a relatively high performance of 185 mW cm- 2 at 700 C, with a high electrolyte film conductivity of 4 × 10- 3 S cm- 1 at 600 C. © 2013 Elsevier B.V.

  7. Tailoring properties of reduced graphene oxide by oxygen plasma treatment

    Science.gov (United States)

    Kondratowicz, Izabela; Nadolska, Małgorzata; Şahin, Samet; Łapiński, Marcin; Prześniak-Welenc, Marta; Sawczak, Mirosław; Yu, Eileen H.; Sadowski, Wojciech; Żelechowska, Kamila

    2018-05-01

    We report an easily controllable, eco-friendly method for tailoring the properties of reduced graphene oxide (rGO) by means of oxygen plasma. The effect of oxygen plasma treatment time (1, 5 and 10 min) on the surface properties of rGO was evaluated. Physicochemical characterization using microscopic, spectroscopic and thermal techniques was performed. The results revealed that different oxygen-containing groups (e.g. carboxyl, hydroxyl) were introduced on the rGO surface enhancing its wettability. Furthermore, upon longer treatment time, other functionalities were created (e.g. quinones, lactones). Moreover, external surface of rGO was partially etched resulting in an increase of the material surface area and porosity. Finally, the oxygen plasma-treated rGO electrodes with bilirubin oxidase were tested for oxygen reduction reaction. The study showed that rGO treated for 10 min exhibited twofold higher current density than untreated rGO. The oxygen plasma treatment may improve the enzyme adsorption on rGO electrodes by introduction of oxygen moieties and increasing the porosity.

  8. Solid oxide fuel cells with apatite-type lanthanum silicate-based electrolyte films deposited by radio frequency magnetron sputtering

    Science.gov (United States)

    Liu, Yi-Xin; Wang, Sea-Fue; Hsu, Yung-Fu; Wang, Chi-Hua

    2018-03-01

    In this study, solid oxide fuel cells (SOFCs) containing high-quality apatite-type magnesium doped lanthanum silicate-based electrolyte films (LSMO) deposited by RF magnetron sputtering are successfully fabricated. The LSMO film deposited at an Ar:O2 ratio of 6:4 on an anode supported NiO/Sm0.2Ce0·8O2-δ (SDC) substrate followed by post-annealing at 1000 °C reveals a uniform and dense c-axis oriented polycrystalline structure, which is well adhered to the anode substrate. A composite SDC/La0·6Sr0·4Co0·2Fe0·8O3-δ cathode layer is subsequently screen-printed on the LSMO deposited anode substrate and fired. The SOFC fabricated with the LSMO film exhibits good mechanical integrity. The single cell with the LSMO layer of ≈2.8 μm thickness reports a total cell resistance of 1.156 and 0.163 Ωcm2, open circuit voltage of 1.051 and 0.982 V, and maximum power densities of 0.212 and 1.490 Wcm-2 at measurement temperatures of 700 and 850 °C, respectively, which are comparable or superior to those of previously reported SOFCs with yttria stabilized zirconia electrolyte films. The results of the present study demonstrate the feasibility of deposition of high-quality LSMO films by RF magnetron sputtering on NiO-SDC anode substrates for the fabrication of SOFCs with good cell performance.

  9. Modification of graphene oxide films by radiofrequency N2 plasma

    Science.gov (United States)

    Neustroev, E. P.; Burtseva, E. K.; Soloviev, B. D.; Prokopiev, A. R.; Popov, V. I.; Timofeev, V. B.

    2018-04-01

    The effect of treatment in nitrogen plasma on the properties of partially reduced graphene oxide (rGO) was studied. A comparison is made between two different sample locations in the reaction chamber. It is shown that in the case when rGO films were turned towards the inductor of the plasma system, the etching rate is much higher. Effective nitrogen functionalization of rGO was established in the second position, when the rGO films were turned in the opposite direction. In this case, the nitrogen content increases to 5 at% of the initial value. The change in the current-voltage characteristics is observed under illumination, which is independent of the wavelength. On and off daylight changes the resistance to 30% of the initial value. The magnitude of the photocurrent increases depending on the applied voltage. The effect is most noticeable for thin rGO films 10-15 nm in thickness.

  10. Steam Electrolysis by Proton-Conducting Solid Oxide Electrolysis Cells (SOECs) with Chemically Stable BaZrO3-Based Electrolytes

    KAUST Repository

    Bi, Lei

    2015-07-17

    BaZrO3-based material was applied as the electrolyte for proton-conducting solid oxide fuel cells (SOECs). Compared with the instability of BaCeO3-based proton-conductors, BaZrO3-based material could be a more promising candidate for proton-conducting SOECs due to its excellent chemical stability under H2O conditions, but few reports on this aspect has been made due to the processing difficulty for BaZrO3. Our recent pioneering work has demonstrated the feasibility of using BaZrO3-based electrolyte for SOECs and the fabricated cell achieves relatively high cell performance, which is comparable or even higher than that for BaCeO3-based SOECs and offers better chemical stability. Cell performance can be further improved by tailoring the electrolyte and electrode. © The Electrochemical Society.

  11. A determination, using solid zirconia electrolytes, of the activities of chromium oxide in ferrochromium alloys and slags at 1650 degrees Celsius

    International Nuclear Information System (INIS)

    Wellbeloved, D.B.; Finn, C.W.P.

    1982-01-01

    This report describes the development of a method in which solid zirconia electrolytes are used in the determination of the activities of chromium and chromium oxide in ferrochromium alloys and slags at 1650 degrees Celsius. Problems related to the cracking of electrolytes as a result of thermal shock, the dissolution of electrolytes in slags, and electrical contacts are discussed. Results for the iron-chromium system at 1650 degrees Celsius are found to be in good agreement with published findings. A limited number of results are reported for slag, but these are inconclusive because there was contamination from container materials. A 'gas-phase' cell is described that overcomes most of the problems encountered

  12. Effect of post-weld heat treatment and electrolytic plasma processing on tungsten inert gas welded AISI 4140 alloy steel

    International Nuclear Information System (INIS)

    Dewan, Mohammad W.; Liang, Jiandong; Wahab, M.A.; Okeil, Ayman M.

    2014-01-01

    Highlights: • The effects of PWHT and EPP were explored on TIG welded AISI4140 alloy steel. • All welded samples were checked with PAUT and ensured defect-free before testing. • Residual stresses, hardness, and tensile properties were measured experimentally. • PWHT resulted higher ductility but lower tensile strength for grain refinement. • EPP-treated samples showed higher tensile strength but lower ductility. - Abstract: Post-weld heat treatment (PWHT) is commonly adopted on welded joints and structures to relieve post-weld residual stresses; and restore the mechanical properties and structural integrity. An electrolytic plasma process (EPP) has been developed to improve corrosion behavior and wear resistance of structural materials; and can be employed in other applications and surface modifications aspects. In this study the effects of PWHT and EPP on the residual stresses, micro-hardness, microstructures, and uniaxial tensile properties are explored on tungsten inert gas (TIG) welded AISI-4140 alloys steel with SAE-4130 chromium–molybdenum alloy welding filler rod. For rational comparison all of the welded samples are checked with nondestructive Phased Array Ultrasonic Testing (PAUT) and to ensure defect-free samples before testing. Residual stresses are assessed with ultrasonic testing at different distances from weld center line. PWHT resulted in relief of tensile residual stress due to grain refinement. As a consequence higher ductility but lower strength existed in PWHT samples. In comparison, EPP-treated samples revealed lower residual stresses, but no significant variation on the grain refinement. Consequently, EPP-treated specimens exhibited higher tensile strength but lower ductility and toughness for the martensitic formation due to the rapid heating and quenching effects. EPP was also applied on PWHT samples, but which did not reveal any substantial effect on the tensile properties after PWHT at 650 °C. Finally the microstructures and

  13. Characteristics of Honeycomb-Type Oxygen Generator with Electrolyte Based on Doped Bismuth Oxide

    Science.gov (United States)

    Chen, Yu-Wen; Liu, Yi-Xin; Wang, Sea-Fue; Devasenathipathy, Rajkumar

    2018-03-01

    An oxygen generator using Y-doped Bi2O3 as electrolyte to transport oxygen ions has been developed, having honeycomb-type structure with dimensions of 40 mm × 35 mm × 30 mm and consisting of 13 × 12 channels. External wire circuitry for the channels arrayed using parallel, series, and hybrid connection was evaluated to achieve the best oxygen separation efficiency. It was observed that the oxygen generator with hybrid connection facilitated evolution of oxygen at maximum of 117 sccm and high purity > 99.9% at 550°C under current flow of 14 A. Addition of 5 wt.% silane and 3 wt.% glass-ceramic powder to the Ag slurry used at both electrodes not only increased the coverage of the metal electrode on the ceramic substrate during dip coating but also prevented cracking at the electrode layer of the module under stress from the electric field and temperature during high-temperature operation, thus reducing the decay rate of the oxygen generator in durability testing.

  14. Titanium-Niobium Oxides as Non-Noble Metal Cathodes for Polymer Electrolyte Fuel Cells

    Directory of Open Access Journals (Sweden)

    Akimitsu Ishihara

    2015-07-01

    Full Text Available In order to develop noble-metal- and carbon-free cathodes, titanium-niobium oxides were prepared as active materials for oxide-based cathodes and the factors affecting the oxygen reduction reaction (ORR activity were evaluated. The high concentration sol-gel method was employed to prepare the precursor. Heat treatment in Ar containing 4% H2 at 700–900 °C was effective for conferring ORR activity to the oxide. Notably, the onset potential for the ORR of the catalyst prepared at 700 °C was approximately 1.0 V vs. RHE, resulting in high quality active sites for the ORR. X-ray (diffraction and photoelectron spectroscopic analyses and ionization potential measurements suggested that localized electronic energy levels were produced via heat treatment under reductive atmosphere. Adsorption of oxygen molecules on the oxide may be governed by the localized electronic energy levels produced by the valence changes induced by substitutional metal ions and/or oxygen vacancies.

  15. Destruction of organic wastes by ammonium peroxydisulfate with electrolytic regeneration of the oxidant

    International Nuclear Information System (INIS)

    Cooper, J.F.; Wang, J.F.; Krueger, R.; King, K.

    1997-01-01

    Research is reported concerning a new aqueous process for oxidative destruction of solid- and liquid organic wastes. This process uses acidified ammonium peroxydisulfate and operates at ambient pressure and at 80- to 100 degrees C. The oxidant may be efficiently regenerated by electrolysis of the sulfate by-product at Pt anodes, even in the presence of organic and inorganic contaminants expected to be entrained in the cycle. Integral rate constants were determined for the oxidation of 25 diverse organic compounds at low (50 ppm) concentrations through fixed-time experiments with excess oxidant and a Pt wire catalyst. For high initial concentrations, uncatalyzed mineralization rates were measured for waste surrogates including kerosene, triethylamine, ion exchange resin, oxalic acid, trinitrotoluene, and cellulose. A packed bed reactor was tested with ethylene glycol, with offgas analysis by mass spectroscopy. Rate data extrapolate to throughputs of approximately 200 kg/m 3 -day. The process may benefit the destruction of highly toxic or specialized industrial wastes as well as the organic fraction of mixed wastes

  16. Electrochemical Oxidation of Silver and Copper in Aqueous Basic Media and in Fused Hydroxide Electrolytes

    Directory of Open Access Journals (Sweden)

    Tejada-Rosales, E. M.

    2004-04-01

    Full Text Available The anodic oxidations of copper and silver electrodes in basic media are reported. Experiments were conducted both in aqueous NaOH solutions and in a flux of molten NaOH/KOH eutectic. The oxidation processes were studied by means of cyclic voltammetry and chronoamperometries and the phases obtained were systematically characterized by x-ray diffraction. The ranges of stability of each phase in the different media studied are reported. In addition to known oxides of copper or silver, a new silver oxide was isolated.

    En este trabajo se describe la oxidación anódico de electrodos de plata y de cobre en medios básicos. Se han utilizado tanto medios acuosos como hidróxidos fundidos (eutéctico NaOH/KOH. Los procesos de oxidación se han estudiado mediante voltametría cíclica y cronoamperometría, y las fases resultantes han sido caracterizadas por difracción de Rayos X. Los rangos de estabilidad encontrados para cada uno dependen del medio utilizado. Además de óxidos conocidos de cobre y de plata, se ha aislado un nuevo óxido de plata.

  17. The electrochemical transfer reactions and the structure of the iron|oxide layer|electrolyte interface

    International Nuclear Information System (INIS)

    Petrović, Željka; Metikoš-Huković, Mirjana; Babić, Ranko

    2012-01-01

    The thickness, barrier (protecting) and semiconducting properties of the potentiostatically formed oxide films on the pure iron electrode in an aqueous borate buffer solution were investigated by electrochemical quartz crystal nanobalance (EQCN), electrochemical impedance spectroscopy (EIS), and Mott–Schottky (MS) analysis. The thicknesses of the prepassive Fe(II)hydroxide layer (up to monolayer) nucleated on the bare iron surface and the passive Fe(II)/Fe(III) layer (up to 2 nm), deposited on the top of the first one, were determined using in situ gravimetry. Electronic properties of iron prepassive and passive films as well as ionic and electronic transfer reactions at the film|solution interface were discussed on the basis of a band structure model of the surface oxide film and the potential distribution at the interface. The anodic oxide film formation and cathodic decomposition are coupled processes and their reversible inter-conversion is mediated by the availability of free charge carriers on the electrode|solution interface. The structure of the reversible double layer at the iron oxide|solution interface was discussed based on the concept of the specific adsorption of the imidazolium cation on the negatively charged electrode surface at pH > pH pzc .

  18. Pt supported on nanosized oxides for electrocatalyst used in polymer electrolyte fuel cells

    DEFF Research Database (Denmark)

    Banu, N.; Serban, E. C.; Marinescu, A.

    2011-01-01

    Even though Pt is a standard catalyst for fuel cells, new advanced materials with low activation energy and high specific surface area are required. Researches proved that conducting oxides are the emerging candidates as support for Pt catalysts targeting replacement of nanocarbons. This paper pr...

  19. An open circuit voltage equation enabling separation of cathode and anode polarization resistances of ceria electrolyte based solid oxide fuel cells

    Science.gov (United States)

    Zhang, Yanxiang; Chen, Yu; Yan, Mufu

    2017-07-01

    The open circuit voltage (OCV) of solid oxide fuel cells is generally overestimated by the Nernst equation and the Wagner equation, due to the polarization losses at electrodes. Considering both the electronic conduction of electrolyte and the electrode polarization losses, we express the OCV as an implicit function of the characteristic oxygen pressure of electrolyte (p* [atm], at which the electronic and ionic conductivities are the same), and the relative polarization resistance of electrodes (rc = Rc/Ri and ra = Ra/Ri, where Ri/c/a [Ωcm2] denotes the ionic resistance of electrolyte, and the polarization resistances of cathode and anode, respectively). This equation approaches to the Wagner equation when the electrodes are highly active (rc and ra → 0), and approaches to the Nernst equation when the electrolyte is a purely ionic conductor (p* → 0). For the fuel cells whose OCV is well below the prediction of the Wagner equation, for example with thin doped ceria electrolyte, it is demonstrated that the combination of OCV and impedance spectroscopy measurements allows the determination of p*, Rc and Ra. This equation can serve as a simple yet powerful tool to study the internal losses in the cell under open circuit condition.

  20. Boron cross-linked graphene oxide/polyvinyl alcohol nanocomposite gel electrolyte for flexible solid-state electric double layer capacitor with high performance

    KAUST Repository

    Huang, Yi-Fu; Wu, Peng-Fei; Zhang, Ming-Qiu; Ruan, Wen-Hong; Giannelis, Emmanuel P.

    2014-01-01

    A new family of boron cross-linked graphene oxide/polyvinyl alcohol (GO-B-PVA) nanocomposite gels is prepared by freeze-thaw/boron cross-linking method. Then the gel electrolytes saturated with KOH solution are assembled into electric double layer capacitors (EDLCs). Structure, thermal and mechanical properties of GO-B-PVA are explored. The electrochemical properties of EDLCs using GO-B-PVA/KOH are investigated, and compared with those using GO-PVA/KOH gel or KOH solution electrolyte. FTIR shows that boron cross-links are introduced into GO-PVA, while the boronic structure inserted into agglomerated GO sheets is demonstrated by DMA analysis. The synergy effect of the GO and the boron crosslinking benefits for ionic conductivity due to unblocking ion channels, and for improvement of thermal stability and mechanical properties of the electrolytes. Higher specific capacitance and better cycle stability of EDLCs are obtained by using the GO-B-PVA/KOH electrolyte, especially the one at higher GO content. The nanocomposite gel electrolytes with excellent electrochemical properties and solid-like character are candidates for the industrial application in high-performance flexible solid-state EDLCs. © 2014 Elsevier Ltd.

  1. Boron cross-linked graphene oxide/polyvinyl alcohol nanocomposite gel electrolyte for flexible solid-state electric double layer capacitor with high performance

    KAUST Repository

    Huang, Yi-Fu

    2014-06-01

    A new family of boron cross-linked graphene oxide/polyvinyl alcohol (GO-B-PVA) nanocomposite gels is prepared by freeze-thaw/boron cross-linking method. Then the gel electrolytes saturated with KOH solution are assembled into electric double layer capacitors (EDLCs). Structure, thermal and mechanical properties of GO-B-PVA are explored. The electrochemical properties of EDLCs using GO-B-PVA/KOH are investigated, and compared with those using GO-PVA/KOH gel or KOH solution electrolyte. FTIR shows that boron cross-links are introduced into GO-PVA, while the boronic structure inserted into agglomerated GO sheets is demonstrated by DMA analysis. The synergy effect of the GO and the boron crosslinking benefits for ionic conductivity due to unblocking ion channels, and for improvement of thermal stability and mechanical properties of the electrolytes. Higher specific capacitance and better cycle stability of EDLCs are obtained by using the GO-B-PVA/KOH electrolyte, especially the one at higher GO content. The nanocomposite gel electrolytes with excellent electrochemical properties and solid-like character are candidates for the industrial application in high-performance flexible solid-state EDLCs. © 2014 Elsevier Ltd.

  2. -3000 V dc bias Ti oxidation by inductively coupled plasma

    International Nuclear Information System (INIS)

    Valencia-Alvarado, R; Lopez-Callejas, R; Barocio, S R; Mercado-Cabrera, A; Pena-Eguiluz, R; Munoz-Castro, A E; De la Piedad-Beneitez, A; De la Rosa-Vazquez, J

    2008-01-01

    Broadening the outer oxidized layer of titanium by means of plasmas commands considerable interest in the biomedical research area due to its potential in human biocompatibility enhancement. Some early results of titanium substrate superficial oxidation experiments which have been conducted in a cylindrical vessel inductively coupled to a 13.56 MHz RF generator with a 500 W output are presented. The oxidation process was carried out in a 20 % oxygen and 80 % argon mixture at work pressures in the 5x10 -3 -1 mbar range, while the samples were dc biased down to -3000 V. The substrate temperature appears to be directly dependent on this voltage, reaching 685 deg. C at the maximum bias when a diffusive oxidation process gives rise to the TiO 2 and α-TiO rutile phases. These were characterized by means of x-ray diffraction and scanning electron microscopy revealing atomic percentage concentrations of oxygen, with respect to those of titanium, between 68 and 13 at.%. The optimum modified layer depth reached 5 μm at a 5x10 -2 mbar work pressure.

  3. A Graphite Oxide Paper Polymer Electrolyte for Direct Methanol Fuel Cells

    Directory of Open Access Journals (Sweden)

    Ravi Kumar

    2011-01-01

    Full Text Available A flow directed assembly of graphite oxide solution was used in the formation of free-standing graphene oxide paper of approximate thickness of 100 μm. The GO papers were characterised by XRD and SEM. Electrochemical characterization of the GO paper membrane electrode assembly revealed proton conductivities of 4.1 × 10−2 S cm−1 to 8.2 × 10−2 S cm−1 at temperatures of 25–90°C. A direct methanol fuel cell, at 60°C, gave a peak power density of 8 mW cm−2 at a current density of 35 mA cm−2.

  4. Direct reform of graphite oxide electrodes by using ambient plasma for supercapacitor applications

    Science.gov (United States)

    Kim, Ho Jun; Jeong, Hae Kyung

    2017-10-01

    Ambient plasma is applied to graphite oxide electrodes directly to improve electrochemical properties for supercapacitor applications. Surface morphology of the electrodes after the plasma treatment changes dramatically and amount of oxygen reduced significantly, demonstrating a reduction effect on the graphite oxide electrode by the ambient plasma. Equivalent series resistance of the electrode also reduced from 108 Ω to 84 Ω after the plasma treatment. Corresponding specific capacitance, therefore, increases from 0.45 F cm-2 to 0.85 F cm-2, proving that the ambient plasma treatment is very efficient, clean, economic, and environment-friendly method to reform the graphite oxide electrodes directly for the supercapacitor applications.

  5. Polymer Electrolytes

    Science.gov (United States)

    Hallinan, Daniel T.; Balsara, Nitash P.

    2013-07-01

    This review article covers applications in which polymer electrolytes are used: lithium batteries, fuel cells, and water desalination. The ideas of electrochemical potential, salt activity, and ion transport are presented in the context of these applications. Potential is defined, and we show how a cell potential measurement can be used to ascertain salt activity. The transport parameters needed to fully specify a binary electrolyte (salt + solvent) are presented. We define five fundamentally different types of homogeneous electrolytes: type I (classical liquid electrolytes), type II (gel electrolytes), type III (dry polymer electrolytes), type IV (dry single-ion-conducting polymer electrolytes), and type V (solvated single-ion-conducting polymer electrolytes). Typical values of transport parameters are provided for all types of electrolytes. Comparison among the values provides insight into the transport mechanisms occurring in polymer electrolytes. It is desirable to decouple the mechanical properties of polymer electrolyte membranes from the ionic conductivity. One way to accomplish this is through the development of microphase-separated polymers, wherein one of the microphases conducts ions while the other enhances the mechanical rigidity of the heterogeneous polymer electrolyte. We cover all three types of conducting polymer electrolyte phases (types III, IV, and V). We present a simple framework that relates the transport parameters of heterogeneous electrolytes to homogeneous analogs. We conclude by discussing electrochemical stability of electrolytes and the effects of water contamination because of their relevance to applications such as lithium ion batteries.

  6. Remote plasma-enhanced metalorganic chemical vapor deposition of aluminum oxide thin films

    NARCIS (Netherlands)

    Volintiru, I.; Creatore, M.; Hemmen, van J.L.; Sanden, van de M.C.M.

    2008-01-01

    Aluminum oxide films were deposited using remote plasma-enhanced metalorganic chemical vapor deposition from oxygen/trimethylaluminum mixtures. Initial studies by in situ spectroscopic ellipsometry demonstrated that the aluminum oxide films deposited at temperatures

  7. Nitric oxide, cholesterol oxides and endothelium-dependent vasodilation in plasma of patients with essential hypertension

    Directory of Open Access Journals (Sweden)

    P. Moriel

    2002-11-01

    Full Text Available The objective of the present study was to identify disturbances of nitric oxide radical (·NO metabolism and the formation of cholesterol oxidation products in human essential hypertension. The concentrations of·NO derivatives (nitrite, nitrate, S-nitrosothiols and nitrotyrosine, water and lipid-soluble antioxidants and cholesterol oxides were measured in plasma of 11 patients with mild essential hypertension (H: 57.8 ± 9.7 years; blood pressure, 148.3 ± 24.8/90.8 ± 10.2 mmHg and in 11 healthy subjects (N: 48.4 ± 7.0 years; blood pressure, 119.4 ± 9.4/75.0 ± 8.0 mmHg.Nitrite, nitrate and S-nitrosothiols were measured by chemiluminescence and nitrotyrosine was determined by ELISA. Antioxidants were determined by reverse-phase HPLC and cholesterol oxides by gas chromatography. Hypertensive patients had reduced endothelium-dependent vasodilation in response to reactive hyperemia (H: 9.3 and N: 15.1% increase of diameter 90 s after hyperemia, and lower levels of ascorbate (H: 29.2 ± 26.0, N: 54.2 ± 24.9 µM, urate (H: 108.5 ± 18.9, N: 156.4 ± 26.3 µM, ß-carotene (H: 1.1 ± 0.8, N: 2.5 ± 1.2 nmol/mg cholesterol, and lycopene (H: 0.4 ± 0.2, N: 0.7 ± 0.2 nmol/mg cholesterol, in plasma, compared to normotensive subjects. The content of 7-ketocholesterol, 5alpha-cholestane-3ß,5,6ß-triol and 5,6alpha-epoxy-5alpha-cholestan-3alpha-ol in LDL, and the concentration of endothelin-1 (H: 0.9 ± 0.2, N: 0.7 ± 0.1 ng/ml in plasma were increased in hypertensive patients. No differences were found for ·NO derivatives between groups. These data suggest that an increase in cholesterol oxidation is associated with endothelium dysfunction in essential hypertension and oxidative stress, although ·NO metabolite levels in plasma are not modified in the presence of elevated cholesterol oxides.

  8. Enhanced Proton Conductivity and Methanol Permeability Reduction via Sodium Alginate Electrolyte-Sulfonated Graphene Oxide Bio-membrane

    Science.gov (United States)

    Shaari, N.; Kamarudin, S. K.; Basri, S.; Shyuan, L. K.; Masdar, M. S.; Nordin, D.

    2018-03-01

    The high methanol crossover and high cost of Nafion® membrane are the major challenges for direct methanol fuel cell application. With the aim of solving these problems, a non-Nafion polymer electrolyte membrane with low methanol permeability and high proton conductivity based on the sodium alginate (SA) polymer as the matrix and sulfonated graphene oxide (SGO) as an inorganic filler (0.02-0.2 wt%) was prepared by a simple solution casting technique. The strong electrostatic attraction between -SO3H of SGO and the sodium alginate polymer increased the mechanical stability, optimized the water absorption and thus inhibited the methanol crossover in the membrane. The optimum properties and performances were presented by the SA/SGO membrane with a loading of 0.2 wt% SGO, which gave a proton conductivity of 13.2 × 10-3 Scm-1, and the methanol permeability was 1.535 × 10-7 cm2 s-1 at 25 °C, far below that of Nafion (25.1 × 10-7 cm2 s-1) at 25 °C. The mechanical properties of the sodium alginate polymer in terms of tensile strength and elongation at break were improved by the addition of SGO.

  9. High-performance Platinum-free oxygen reduction reaction and hydrogen oxidation reaction catalyst in polymer electrolyte membrane fuel cell.

    Science.gov (United States)

    Chandran, Priji; Ghosh, Arpita; Ramaprabhu, Sundara

    2018-02-26

    The integration of polymer electrolyte membrane fuel cell (PEMFC) stack into vehicles necessitates the replacement of high-priced platinum (Pt)-based electrocatalyst, which contributes to about 45% of the cost of the stack. The implementation of high-performance and durable Pt metal-free catalyst for both oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR) could significantly enable large-scale commercialization of fuel cell-powered vehicles. Towards this goal, a simple, scalable, single-step synthesis method was adopted to develop palladium-cobalt alloy supported on nitrogen-doped reduced graphene oxide (Pd 3 Co/NG) nanocomposite. Rotating ring-disk electrode (RRDE) studies for the electrochemical activity towards ORR indicates that ORR proceeds via nearly four-electron mechanism. Besides, the mass activity of Pd 3 Co/NG shows an enhancement of 1.6 times compared to that of Pd/NG. The full fuel cell measurements were carried out using Pd 3 Co/NG at the anode, cathode in conjunction with Pt/C and simultaneously at both anode and cathode. A maximum power density of 68 mW/cm 2 is accomplished from the simultaneous use of Pd 3 Co/NG as both anode and cathode electrocatalyst with individual loading of 0.5 mg/cm 2 at 60 °C without any backpressure. To the best of our knowledge, the present study is the first of its kind of a fully non-Pt based PEM full cell.

  10. Effect of a ten-week Nordic Walking exercise program on serum electrolyte concentration and plasma acid-base balance in postmenopausal women with overweight or obesity

    OpenAIRE

    Kałużny, Krystian; Kałużna, Anna; Budzyński, Jacek; Hagner, Wojciech; Kochański, Bartosz; Żukow, Walery; Bronisz, Agata; Hagner‑Derengowska, Magdalena

    2016-01-01

    Kałużny Krystian, Kałużna Anna, Budzyński Jacek, Hagner Wojciech, Kochański Bartosz, Żukow Walery, Bronisz Agata, Hagner‑Derengowska Magdalena. Effect of a ten-week Nordic Walking exercise program on serum electrolyte concentration and plasma acid-base balance in postmenopausal women with overweight or obesity. Journal of Education, Health and Sport. 2016;6(12):353-364. eISSN 2391-8306. DOI http://dx.doi.org/10.5281/zenodo.201929 http://ojs.ukw.edu.pl/index.php/johs/article/view/4065 ...

  11. SmBaCoCuO5+x as cathode material based on GDC electrolyte for intermediate-temperature solid oxide fuel cells

    International Nuclear Information System (INIS)

    Lue Shiquan; Long, Guohui; Ji Yuan; Meng Xiangwei; Zhao Hongyuan; Sun Cuicui

    2011-01-01

    Research highlights: → We synthesize a new kind of layered perovskite SmBaCoCuO 5+x (SBCCO) as a cathode material of a solid oxide fuel cell. → There are some reports on the performance of cathodes in proton-conducting SOFCs based on BaCe 0.8 Sm 0.2 O 3-δ electrolyte. → However, to the best of our knowledge, the performance of SBCCO cathodes in oxygen-ion conducting SOFCs has not been reported to date. → In this work, the ceramic powder SBCCO is examined as a cathode for IT-SOFCs based on Ce 0.9 Gd 0.1 O 1.95 (GDC) electrolyte. - Abstract: The performance of SmBaCoCuO 5+x (SBCCO) cathode has been investigated for their potential utilization in intermediate-temperature solid oxide fuel cells (IT-SOFCs). The powder X-ray diffraction (XRD), thermal expansion and electrochemical performance on Ce 0.9 Gd 0.1 O 1.95 (GDC) electrolyte are evaluated. XRD results show that there is no chemical reaction between SBCCO cathode and GDC electrolyte when the temperature is below 950 o C. The thermal expansion coefficient (TEC) value of SBCCO is 15.53 x 10 -6 K -1 , which is ∼23% lower than the TEC of the SmBaCo 2 O 5+x (SBCO) sample. The electrochemical impedance spectra reveals that SBCCO symmetrical half-cells by sintering at 950 deg. C has the best electrochemical performance and the area specific resistance (ASR) of SBCCO cathode is as low as 0.086 Ω cm 2 at 800 o C. An electrolyte-supported fuel cell generates good performance with the maximum power density of 517 mW cm -2 at 800 deg. C in H 2 . Preliminary results indicate that SBCCO is promising as a cathode for IT-SOFCs.

  12. Surface-protected LiCoO2 with ultrathin solid oxide electrolyte film for high-voltage lithium ion batteries and lithium polymer batteries

    Science.gov (United States)

    Yang, Qi; Huang, Jie; Li, Yejing; Wang, Yi; Qiu, Jiliang; Zhang, Jienan; Yu, Huigen; Yu, Xiqian; Li, Hong; Chen, Liquan

    2018-06-01

    Surface modification of LiCoO2 with the ultrathin film of solid state electrolyte of Li1.4Al0.4Ti1.6(PO4)3 (LATP) has been realized by a new and facile solution-based method. The coated LiCoO2 reveals enhanced structural and electrochemical stability at high voltage (4.5 V vs Li+/Li) in half-cell with liquid electrolyte. Transmission electron microscopy (TEM) images show that a dense LATP coating layer is covered on the surface of LiCoO2 uniformly with thickness of less than 20 nm. The LATP coating layer is proven to be able to prevent the direct contact between the cathode and the electrolyte effectively and thus to suppress the side reactions of liquid electrolyte with LiCoO2 surface at high charging voltage. As a result, dissolution of Co3+ has been largely suppressed over prolonged cycling as indicated by the X-ray photoelectron spectroscopy (XPS) measurements. Due to this surface passivating feature, the electrochemical performance of 0.5 wt% LATP modified LiCoO2 has also been evaluated in an all solid lithium battery with poly(ethylene oxide)-based polymer electrolyte. The cell exhibits 93% discharge capacity retention of the initial discharge capacity after 50 cycles at the charging cut-off voltage of 4.2 V, suggesting that the LATP coating layer is effective to suppress the oxidation of PEO at high voltage.

  13. The role of electrolyte anions (ClO4-, NO3-, and Cl-) in divalent metal (M2+) adsorption on oxide and hydroxide surfaces in salt solutions

    International Nuclear Information System (INIS)

    Criscenti, L.J.; Sverjensky, D.A.

    1999-01-01

    Adsorption of divalent metal ions (M 2+ ) onto oxide and hydroxide surfaces from solutions of strong electrolytes has typically been inferred to take place without the involvement of the electrolyte anion. Only in situations where M 2+ forms a strong enough aqueous complex with the electrolyte anion (for example, CdCl + or PbCl + ) has it been frequently suggested that the metal and the electrolyte anion adsorb simultaneously. A review of experimental data for the adsorption of Cd 2+ , Pb 2+ , Co 2+ , UO 2 2+ , Zn 2+ , Cu 2+ , Ba 2+ , Sr 2+ , and Ca 2+ onto quartz, silica, goethite, hydrous ferric oxide, corundum, γ-alumina, anatase, birnessite, and magnetite, from NaNO 3 , KNO 3 , NaCl, and NaClO 4 solutions over a wide range of ionic strengths (0.0001 M-1.0 M), reveals that transition and heavy metal adsorption behavior with ionic strength is a function of the type of electrolyte. In NaNO 3 solutions, metal adsorption exhibits little or no dependence on the ionic strength of the solution. However, in NaCl solutions, transition and heavy metal adsorption decreases strongly with increasing ionic strength. In NaClO 4 solutions, metal adsorption decreases strongly with increasing ionic strength. In NaClO 4 solutions, metal adsorption exhibits little dependence on ionic strength but is often suggestive of an increase in metal adsorption with increasing ionic strength. Analysis of selected adsorption edges was carried out using the extended triple-layer model and aqueous speciation models that included metal-nitrate, metal-chloride, and metal-hydroxide complexes

  14. Synthesis, processing and characterization of the solid oxide half-cells cathode/electrolyte of strontium-doped lanthanum manganite/Yttria-stabilized zirconia

    International Nuclear Information System (INIS)

    Chiba, Rubens

    2010-01-01

    The ceramic films of strontium-doped lanthanum manganite (LSM) and strontium doped lanthanum manganite/Yttria-stabilized zirconia (LSM/YSZ) are used as cathodes of the high temperature solid oxide fuel cells (HTSOFC). These porous ceramic films had been deposited on the YSZ dense ceramic substrate, used as electrolyte, structural component of the module, thus conferring a configuration of half-cell called auto-support. The study of the half-cell it is basic, therefore in the interface cathode/electrolyte occurs the oxygen reduction reaction, consequently influencing in the performance of the HTSOFC. In this direction, the present work contributes for the processing of thin films, using the wet powder spraying technique, adopted for the conformation of the ceramic films for allowing the attainment of porous layers with thicknesses varied in the order of micrometers. The LSM powders were synthesized by the citrate technique and the LSM/YSZ powders synthesized by the solid mixture technique. In the stage of formation were prepared organic suspensions of LSM and LSM/YSZ fed by gravity in a manual aerograph. For the formation of the YSZ substrate was used a hydraulic uniaxial press. The attainment of solid oxide half-cells cathode/electrolyte was possible of crystalline structures hexagonal for phase LSM and cubic for phase YSZ. The half-cells micrographs show that the YSZ substrate is dense, enough to be used as solid electrolyte, and the LSM and LSM/YSZ films are presented porous with approximately 30 μm of thickness and good adherence between the cathodes and the electrolyte. The presence of composite cathode between the LSM cathode and YSZ substrate, presented an increase in the electrochemical performance in the oxygen reduction reaction. (author)

  15. Oxidative stress and plasma lipoproteins in cancer patients

    Energy Technology Data Exchange (ETDEWEB)

    Maia, Fernanda Maria Machado; Santos, Emanuelly Barbosa; Reis, Germana Elias [Universidade Estadual do Ceará, Fortaleza, CE (Brazil)

    2014-07-01

    To evaluate the relation between oxidative stress and lipid profile in patients with different types of cancer. This was an observational cross-sectional. A total of 58 subjects were evaluated, 33 males, divided into two groups of 29 patients each: Group 1, patients with cancer of the digestive tract and accessory organs; Group 2 patients with other types of cancers, all admitted to a public hospital. The plasma levels (lipoproteins and total cholesterol, HDL, and triglycerides, for example) were analyzed by enzymatic kits, and oxidative stress based on thiobarbituric acid-reactive substances, by assessing the formation of malondialdehyde. In general the levels of malondialdehyde of patients were high (5.00μM) as compared to 3.31μM for healthy individuals. The median values of lipids exhibited normal triacylglycerol (138.78±89.88mg/dL), desirable total cholesterol values (163.04±172.38mg/dL), borderline high LDL (151.30±178.25mg/dL) and low HDL (31.70±22.74mg/dL). Median HDL levels in Group 1 were lower (31.32mg/dL) than the cancer patients in Group 2 (43.67mg/dL) (p=0.038). Group 1 also showed higher levels of oxidative stress (p=0.027). The lipid profile of patients with cancer was not favorable, which seems to have contributed to higher lipid peroxidation rate, generating a significant oxidative stress.

  16. Nanoscale Organic Hybrid Electrolytes

    KAUST Repository

    Nugent, Jennifer L.

    2010-08-20

    Nanoscale organic hybrid electrolytes are composed of organic-inorganic hybrid nanostructures, each with a metal oxide or metallic nanoparticle core densely grafted with an ion-conducting polyethylene glycol corona - doped with lithium salt. These materials form novel solvent-free hybrid electrolytes that are particle-rich, soft glasses at room temperature; yet manifest high ionic conductivity and good electrochemical stability above 5V. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Nanoscale Organic Hybrid Electrolytes

    KAUST Repository

    Nugent, Jennifer L.; Moganty, Surya S.; Archer, Lynden A.

    2010-01-01

    Nanoscale organic hybrid electrolytes are composed of organic-inorganic hybrid nanostructures, each with a metal oxide or metallic nanoparticle core densely grafted with an ion-conducting polyethylene glycol corona - doped with lithium salt. These materials form novel solvent-free hybrid electrolytes that are particle-rich, soft glasses at room temperature; yet manifest high ionic conductivity and good electrochemical stability above 5V. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Ionic liquids in a poly ethylene oxide cross-linked gel polymer as an electrolyte for electrical double layer capacitor

    Science.gov (United States)

    Chaudoy, V.; Tran Van, F.; Deschamps, M.; Ghamouss, F.

    2017-02-01

    In the present work, we developed a gel polymer electrolyte via the incorporation of a room temperature ionic liquid into a cross-linked polymer matrix. The cross-linked gel electrolyte was prepared using a free radical polymerization of methacrylate and dimethacrylate oligomers dissolved in 1-propyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide. Combining the advantages of the ionic liquids and of conventional polymers, the cross-linked gel polymer electrolyte was used both as a separator and as an electrolyte for a leakage-free and non-flammable EDLC supercapacitor. The quasi-all solid-state supercapacitors showed rather good capacitance, power and energy densities by comparison to a liquid electrolyte-based EDLC.

  19. Biocorrosion resistance of coated magnesium alloy by microarc oxidation in electrolyte containing zirconium and calcium salts

    Science.gov (United States)

    Wang, Ya-Ming; Guo, Jun-Wei; Wu, Yun-Feng; Liu, Yan; Cao, Jian-Yun; Zhou, Yu; Jia, De-Chang

    2014-09-01

    The key to use magnesium alloys as suitable biodegradable implants is how to adjust their degradation rates. We report a strategy to prepare biocompatible ceramic coating with improved biocorrosion resistance property on AZ91D alloy by microarc oxidation (MAO) in a silicate-K2ZrF6 solution with and without Ca(H2PO4)2 additives. The microstructure and biocorrosion of coatings were characterized by XRD and SEM, as well as electrochemical and immersion tests in simulated body fluid (SBF). The results show that the coatings are mainly composed of MgO, Mg2SiO4, m-ZrO2 phases, further Ca containing compounds involve the coating by Ca(H2PO4)2 addition in the silicate-K2ZrF6 solution. The corrosion resistance of coated AZ91D alloy is significantly improved compared with the bare one. After immersing in SBF for 28 d, the Si-Zr5-Ca0 coating indicates a best corrosion resistance performance.

  20. Performance of intermediate temperature (600-800 °C) solid oxide fuel cell based on Sr and Mg doped lanthanum-gallate electrolyte

    Science.gov (United States)

    Gong, Wenquan; Gopalan, Srikanth; Pal, Uday B.

    The solid electrolyte chosen for this investigation was La 0.9Sr 0.1Ga 0.8Mg 0.2O 3 (LSGM). To select appropriate electrode materials from a group of possible candidate materials, AC complex impedance spectroscopy studies were conducted between 600 and 800 °C on symmetrical cells that employed the LSGM electrolyte. Based on the results of the investigation, LSGM electrolyte supported solid oxide fuel cells (SOFCs) were fabricated with La 0.6Sr 0.4Co 0.8Fe 0.2O 3-La 0.9Sr 0.1Ga 0.8Mg 0.2O 3 (LSCF-LSGM) composite cathode and nickel-Ce 0.6La 0.4O 2 (Ni-LDC) composite anode having a barrier layer of Ce 0.6La 0.4O 2 (LDC) between the LSGM electrolyte and the Ni-LDC anode. Electrical performances of these cells were determined and the electrode polarization behavior as a function of cell current was modeled between 600 and 800 °C.

  1. Performance of intermediate temperature (600-800{sup o}C) solid oxide fuel cell based on Sr and Mg doped lanthanum-gallate electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Wenquan; Gopalan, Srikanth; Pal, Uday B. [Department of Manufacturing Engineering, Boston University, MA 02215 (United States)

    2006-09-29

    The solid electrolyte chosen for this investigation was La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 3} (LSGM). To select appropriate electrode materials from a group of possible candidate materials, AC complex impedance spectroscopy studies were conducted between 600 and 800{sup o}C on symmetrical cells that employed the LSGM electrolyte. Based on the results of the investigation, LSGM electrolyte supported solid oxide fuel cells (SOFCs) were fabricated with La{sub 0.6}Sr{sub 0.4}Co{sub 0.8}Fe{sub 0.2}O{sub 3}-La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 3} (LSCF-LSGM) composite cathode and nickel-Ce{sub 0.6}La{sub 0.4}O{sub 2} (Ni-LDC) composite anode having a barrier layer of Ce{sub 0.6}La{sub 0.4}O{sub 2} (LDC) between the LSGM electrolyte and the Ni-LDC anode. Electrical performances of these cells were determined and the electrode polarization behavior as a function of cell current was modeled between 600 and 800{sup o}C. (author)

  2. Self-propagating high-temperature synthesis of La(Sr)Ga(Mg)O3-δ for electrolyte of solid oxide fuel cells

    International Nuclear Information System (INIS)

    Ishikawa, Hiroyuki; Enoki, Makiko; Ishihara, Tatsumi; Akiyama, Tomohiro

    2007-01-01

    This paper describes self-propagating high-temperature synthesis (SHS) of an electrolyte for solid oxide fuel (SOFC), in comparison to a conventional solid-state reaction method (SRM). Doped-lanthanum gallate: La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3-δ (LSGM9182) and LSGM9173 as the SOFC electrolyte, was prepared by the SHS and sintered at different temperatures, for measuring the electrical conductivity of the sintered LSGM and the power generating performance at 1073 K, in comparison to the SRM. In the SHS, the LSGM powders with smaller size were obtained and easily sintered at the 100 K-lower temperature, 1673 K, than in the SRM. Most significantly, the electrical conductivity of the sintered LSGM9182 was as high as 0.11 S cm -1 and its maximum power density was a value of 245 mW cm -2 in the cell configuration of Ni/LSGM9182 (0.501 mm in thickness)/Sm 0.5 Sr 0.5 CoO 3 . The conclusion was that the proposed SHS-sintering method with many benefits of minimizing the energy requirement and the processing time in the production, easing temperature restriction for the sintering, and improving the electrolyte performance up to a conventional level is practicable for producing the LSGM-electrolyte of SOFC at an intermediate-temperature application

  3. Tailoring the electrode-electrolyte interface of Solid Oxide Fuel Cells (SOFC) by laser micro-patterning to improve their electrochemical performance

    Science.gov (United States)

    Cebollero, J. A.; Lahoz, R.; Laguna-Bercero, M. A.; Larrea, A.

    2017-08-01

    Cathode activation polarisation is one of the main contributions to the losses of a Solid Oxide Fuel Cell. To reduce this loss we use a pulsed laser to modify the surface of yttria stabilized zirconia (YSZ) electrolytes to make a corrugated micro-patterning in the mesoscale. The beam of the laser source, 5 ns pulse width and emitting at λ = 532 nm (green region), is computer-controlled to engrave the selected micro-pattern on the electrolyte surface. Several laser scanning procedures and geometries have been tested. Finally, we engrave a square array with 28 μm of lattice parameter and 7 μm in depth on YSZ plates. With these plates we prepare LSM-YSZ/YSZ/LSM-YSZ symmetrical cells (LSM: La1-xSrxMnO3) and determine their activation polarisation by Electrochemical Impedance Spectroscopy (EIS). To get good electrode-electrolyte contact after sintering it is necessary to use pressure-assisted sintering with low loads (about 5 kPa), which do not modify the electrode microstructure. The decrease in polarisation with respect to an unprocessed cell is about 30%. EIS analysis confirms that the reason for this decrease is an improvement in the activation processes at the electrode-electrolyte interface.

  4. Tunable molten oxide pool assisted plasma-melter vitrification systems

    Science.gov (United States)

    Titus, Charles H.; Cohn, Daniel R.; Surma, Jeffrey E.

    1998-01-01

    The present invention provides tunable waste conversion systems and apparatus which have the advantage of highly robust operation and which provide complete or substantially complete conversion of a wide range of waste streams into useful gas and a stable, nonleachable solid product at a single location with greatly reduced air pollution to meet air quality standards. The systems provide the capability for highly efficient conversion of waste into high quality combustible gas and for high efficiency conversion of the gas into electricity by utilizing a high efficiency gas turbine or an internal combustion engine. The solid product can be suitable for various commercial applications. Alternatively, the solid product stream, which is a safe, stable material, may be disposed of without special considerations as hazardous material. In the preferred embodiment, the arc plasma furnace and joule heated melter are formed as a fully integrated unit with a common melt pool having circuit arrangements for the simultaneous independently controllable operation of both the arc plasma and the joule heated portions of the unit without interference with one another. The preferred configuration of this embodiment of the invention utilizes two arc plasma electrodes with an elongated chamber for the molten pool such that the molten pool is capable of providing conducting paths between electrodes. The apparatus may additionally be employed with reduced use or without further use of the gases generated by the conversion process. The apparatus may be employed as a net energy or net electricity producing unit where use of an auxiliary fuel provides the required level of electricity production. Methods and apparatus for converting metals, non-glass forming waste streams and low-ash producing inorganics into a useful gas are also provided. The methods and apparatus for such conversion include the use of a molten oxide pool having predetermined electrical, thermal and physical

  5. Electrolytic trichloroethene degradation using mixed metal oxide coated titanium mesh electrodes.

    Science.gov (United States)

    Petersen, Matthew A; Sale, Thomas C; Reardon, Kenneth F

    2007-04-01

    Electrochemical systems provide a low cost, versatile, and controllable platform to potentially treat contaminants in water, including chlorinated solvents. Relative to bare metal or noble metal amended materials, dimensionally stable electrode materials such as mixed metal oxide coated titanium (Ti/MMO) have advantages in terms of stability and cost, important factors for sustainable remediation solutions. Here, we report the use of Ti/MMO as an effective cathode substrate for treatment of trichloroethene (TCE). TCE degradation in a batch reactor was measured as the decrease of TCE concentration over time and the corresponding evolution of chloride; notably, this occurred without the formation of commonly encountered chlorinated intermediates. The reaction was initiated when Ti/MMO cathode potentials were less than -0.8 V vs. the standard hydrogen electrode, and the rate of TCE degradation increased linearly with progressively more negative potentials. The maximum pseudo-first-order heterogeneous rate constant was approximately 0.05 cm min(-1), which is comparable to more commonly used cathode materials such as nickel. In laboratory-scale flow-though column reactors designed to simulate permeable reactive barriers (PRBs), TCE concentrations were reduced by 80-90%. The extent of TCE flux reduction increased with the applied potential difference across the electrodes and was largely insensitive to the spacing distance between the electrodes. This is the first report of the electrochemical reduction of a chlorinated organic contaminant at a Ti/MMO cathode, and these results support the use of this material in PRBs as a possible approach to manage TCE plume migration.

  6. Disparate effects of oxidation on plasma acyltransferase activities: inhibition of cholesterol esterification but stimulation of transesterification of oxidized phospholipids.

    Science.gov (United States)

    Subbaiah, P V; Liu, M

    1996-05-31

    Oxidation of lipoproteins results in the formation of several polar phospholipids with pro-inflammatory and pro-atherogenic properties. To examine the possible role of lecithin/cholesterol acyltransferase (LCAT) in the metabolism of these oxidized phospholipids, we oxidized whole plasma with either Cu(2+) or a free-radical generator, and determined the various activities of LCAT. Oxidation caused a reduction in plasma phosphatidylcholine (PC), an increase in a short-chain polar PC (SCP-PC), and an inhibition of the transfer of long-chain acyl groups to cholesterol (LCAT activity) or to lyso PC (lysolecithin acyltransferase (LAT) I activity). However, the transfer of short-chain acyl groups from SCP-PC to lyso PCLAT II activity) was stimulated several fold, in direct correlation with the degree of oxidation. LAT II activity was not stimulated by oxidation in LCAT-deficient plasma, showing that it is carried out by LCAT. Oxidized normal plasma exhibited low LCAT activity even in the presence of exogenous proteoliposome substrate, indicating that the depletion of substrate PC was not responsible for the loss of activity. Oxidation of isolated LDL or HDL abolished their ability to support LCAT and LAT I activities of exogenous enzyme, but promoted the LAT II activity. Purified LCAT lost its LCAT and LAT I functions, but not its LAT II function, when oxidized in vitro. These results show that while oxidation of plasma causes a loss of LCAT's ability to transfer long-chain acyl groups, its ability to transfer short-chain acyl groups, from SCP-PC is retained, and even stimulated, suggesting that LCAT may have a physiological role in the metabolism of oxidized PC in plasma.

  7. Serum Trace Elements and Electrolytes Are Associated with Fasting Plasma Glucose and HbA1c in Postmenopausal Women with Type 2 Diabetes Mellitus.

    Science.gov (United States)

    Skalnaya, Margarita G; Skalny, Anatoly V; Yurasov, Vasily V; Demidov, Vasily A; Grabeklis, Andrei R; Radysh, Ivan V; Tinkov, Alexey A

    2017-05-01

    The primary aim of the research was to assess the level of trace elements and electrolytes in serum of postmenopausal diabetic women. Sixty-four postmenopausal women with type 2 diabetes mellitus (DM2) and 64 age- and body mass index-matched controls were examined. Serum trace elements were assessed using inductively coupled plasma dynamic reaction cell mass spectrometry (ICP-DRC-MS). Fasting plasma glucose (FPG) and glycated hemoglobin (HbA 1c ) levels were evaluated using Randox kits. The obtained data demonstrate that DM2 patients were characterized by 42 and 34 % higher FPG and HbA 1c levels, respectively (p women was increased by 10 and 15 % in comparison to the respective control values (p = 0.002 and DM2 pathogenesis. Further studies are required to assess the intimate mechanisms of the observed differences.

  8. Characterization of Ni-YSZ anodes for solid oxide fuel cells fabricated by suspension plasma spraying with axial feedstock injection

    Science.gov (United States)

    Metcalfe, Craig; Kuhn, Joel; Kesler, Olivera

    2013-12-01

    Composite Ni-Y0.15Zr0.85O1.925 anodes were fabricated by axial-injection suspension plasma spraying in open atmosphere conditions. The composition of the anode is controllable by adjustment of the plasma gas composition, stand-off distance, and suspension feed rate. The total porosity is controllable through the addition of carbon black to the suspension as a sacrificial pore-forming material as well as by adjustment of the suspension feed rate. The size of the NiO particles in suspension affects both the composition and total porosity, with larger NiO particles leading to increased Ni content and porosity in the deposited coatings. The surface roughness increases with a decrease of the in-flight droplet momentum, which results from both smaller NiO particles in suspension and the addition of low density pore-forming materials. A solid oxide fuel cell was fabricated with both electrodes and electrolyte fabricated by axial-injection plasma spraying. Peak power densities of 0.718 W cm-2 and 1.13 W cm-2 at 750 °C and 850 °C, respectively, were achieved.

  9. Reduction of a thin chromium oxide film on Inconel surface upon treatment with hydrogen plasma

    Energy Technology Data Exchange (ETDEWEB)

    Vesel, Alenka, E-mail: alenka.vesel@guest.arnes.si [Jozef Stefan Institute, Jamova cesta 39, 1000 Ljubljana (Slovenia); Mozetic, Miran [Jozef Stefan Institute, Jamova cesta 39, 1000 Ljubljana (Slovenia); Balat-Pichelin, Marianne [PROMES-CNRS Laboratory, 7 Rue du four solaire, 66120 Font Romeu Odeillo (France)

    2016-11-30

    Highlights: • Oxidized Inconel alloy was exposed to hydrogen at temperatures up to 1500 K. • Oxide reduction in hydrogen plasma started at approximately 1300 K. • AES depth profiling revealed complete reduction of oxides in plasma. • Oxides were not reduced, if the sample was heated just in hydrogen atmosphere. • Surface of reduced Inconel preserved the same composition as the bulk material. - Abstract: Inconel samples with a surface oxide film composed of solely chromium oxide with a thickness of approximately 700 nm were exposed to low-pressure hydrogen plasma at elevated temperatures to determine the suitable parameters for reduction of the oxide film. The hydrogen pressure during treatment was set to 60 Pa. Plasma was created by a surfaguide microwave discharge in a quartz glass tube to allow for a high dissociation fraction of hydrogen molecules. Auger electron depth profiling (AES) was used to determine the decay of the oxygen in the surface film and X-ray diffraction (XRD) to measure structural modifications. During hydrogen plasma treatment, the oxidized Inconel samples were heated to elevated temperatures. The reduction of the oxide film started at temperatures of approximately 1300 K (considering the emissivity of 0.85) and the oxide was reduced in about 10 s of treatment as revealed by AES. The XRD showed sharper substrate peaks after the reduction. Samples treated in hydrogen atmosphere under the same conditions have not been reduced up to approximately 1500 K indicating usefulness of plasma treatment.

  10. Low temperature growth of gallium oxide thin films via plasma enhanced atomic layer deposition

    NARCIS (Netherlands)

    O'Donoghue, R.; Rechmann, J.; Aghaee, M.; Rogalla, D.; Becker, H.-W.; Creatore, M.; Wieck, A.D.; Devi, A.P.K.

    2017-01-01

    Herein we describe an efficient low temperature (60–160 °C) plasma enhanced atomic layer deposition (PEALD) process for gallium oxide (Ga2O3) thin films using hexakis(dimethylamido)digallium [Ga(NMe2)3]2 with oxygen (O2) plasma on Si(100). The use of O2 plasma was found to have a significant

  11. Digital power and performance analysis of inkjet printed ring oscillators based on electrolyte-gated oxide electronics

    Science.gov (United States)

    Cadilha Marques, Gabriel; Garlapati, Suresh Kumar; Dehm, Simone; Dasgupta, Subho; Hahn, Horst; Tahoori, Mehdi; Aghassi-Hagmann, Jasmin

    2017-09-01

    Printed electronic components offer certain technological advantages over their silicon based counterparts, like mechanical flexibility, low process temperatures, maskless and additive manufacturing possibilities. However, to be compatible to the fields of smart sensors, Internet of Things, and wearables, it is essential that devices operate at small supply voltages. In printed electronics, mostly silicon dioxide or organic dielectrics with low dielectric constants have been used as gate isolators, which in turn have resulted in high power transistors operable only at tens of volts. Here, we present inkjet printed circuits which are able to operate at supply voltages as low as ≤2 V. Our transistor technology is based on lithographically patterned drive electrodes, the dimensions of which are carefully kept well within the printing resolutions; the oxide semiconductor, the electrolytic insulator and the top-gate electrodes have been inkjet printed. Our inverters show a gain of ˜4 and 2.3 ms propagation delay time at 1 V supply voltage. Subsequently built 3-stage ring oscillators start to oscillate at a supply voltage of only 0.6 V with a frequency of ˜255 Hz and can reach frequencies up to ˜350 Hz at 2 V supply voltage. Furthermore, we have introduced a systematic methodology for characterizing ring oscillators in the printed electronics domain, which has been largely missing. Benefiting from this procedure, we are now able to predict the switching capacitance and driver capability at each stage, as well as the power consumption of our inkjet printed ring oscillators. These achievements will be essential for analyzing the performance and power characteristics of future inkjet printed digital circuits.

  12. Electrical and stability performance of anode-supported solid oxide fuel cells with strontium- and magnesium-doped lanthanum gallate thin electrolyte

    International Nuclear Information System (INIS)

    Guo Weimin; Liu Jiang; Zhang Yaohui

    2008-01-01

    Anode-supported solid oxide fuel cells (SOFCs) comprising NiO-samarium-doped ceria (SDC) (Sm 0.2 Ce 0.8 O 1.9 ) composite anode, thin tri-layer electrolyte, and La 0.6 Sr 0.4 Co 0.8 Fe 0.2 O 3 (LSCF)-La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3-δ (LSGM) composite cathode were fabricated. The thin tri-layer consisting of an 11-μm thick LSGM electrolyte layer and a 12-μm thick La 0.4 Ce 0.6 O 1.8 (LDC) layer on each side of the LSGM was prepared by centrifugal casting and co-firing technique. The performance of the cells operated with humidified H 2 as fuel and ambient air as oxidant showed a maximum power density of 1.23 W cm -2 at 800 deg. C. A stability test of about 100 h was carried out and some deterioration of output power was observed, while the open circuit voltage (OCV) kept unchanged. Impedance measurements showed that both the electrolyte ohmic resistance and the electrode polarization increased with time and the latter dominated the degradation

  13. Electrical and stability performance of anode-supported solid oxide fuel cells with strontium- and magnesium-doped lanthanum gallate thin electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Guo Weimin [College of Chemistry, South China University of Technology, Guangzhou 510640, Guangdong (China); Liu Jiang [College of Chemistry, South China University of Technology, Guangzhou 510640, Guangdong (China)], E-mail: jiangliu@scut.edu.cn; Zhang Yaohui [College of Chemistry, South China University of Technology, Guangzhou 510640, Guangdong (China)

    2008-05-20

    Anode-supported solid oxide fuel cells (SOFCs) comprising NiO-samarium-doped ceria (SDC) (Sm{sub 0.2}Ce{sub 0.8}O{sub 1.9}) composite anode, thin tri-layer electrolyte, and La{sub 0.6}Sr{sub 0.4}Co{sub 0.8}Fe{sub 0.2}O{sub 3} (LSCF)-La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 3-{delta}} (LSGM) composite cathode were fabricated. The thin tri-layer consisting of an 11-{mu}m thick LSGM electrolyte layer and a 12-{mu}m thick La{sub 0.4}Ce{sub 0.6}O{sub 1.8} (LDC) layer on each side of the LSGM was prepared by centrifugal casting and co-firing technique. The performance of the cells operated with humidified H{sub 2} as fuel and ambient air as oxidant showed a maximum power density of 1.23 W cm{sup -2} at 800 deg. C. A stability test of about 100 h was carried out and some deterioration of output power was observed, while the open circuit voltage (OCV) kept unchanged. Impedance measurements showed that both the electrolyte ohmic resistance and the electrode polarization increased with time and the latter dominated the degradation.

  14. Materials space of solid-state electrolytes: unraveling chemical composition-structure-ionic conductivity relationships in garnet-type metal oxides using cheminformatics virtual screening approaches.

    Science.gov (United States)

    Kireeva, Natalia; Pervov, Vladislav S

    2017-08-09

    The organic electrolytes of most current commercial rechargeable Li-ion batteries (LiBs) are flammable, toxic, and have limited electrochemical energy windows. All-solid-state battery technology promises improved safety, cycling performance, electrochemical stability, and possibility of device miniaturization and enables a number of breakthrough technologies towards the development of new high power and energy density microbatteries for electronics with low processing cost, solid oxide fuel cells, electrochromic devices, etc. Currently, rational materials design is attracting significant attention, which has resulted in a strong demand for methodologies that can accelerate the design of materials with tailored properties; cheminformatics can be considered as an efficient tool in this respect. This study was focused on several aspects: (i) identification of the parameters responsible for high Li-ion conductivity in garnet structured oxides; (ii) development of quantitative models to elucidate composition-structure-Li ionic conductivity relationships, taking into account the experimental details of sample preparation; (iii) circumscription of the materials space of solid garnet-type electrolytes, which is attractive for virtual screening. Several candidate compounds have been recommended for synthesis as potential solid state electrolyte materials.

  15. Fabrication of copper-based anodes via atmosphoric plasma spraying techniques

    Science.gov (United States)

    Lu, Chun [Monroeville, PA

    2012-04-24

    A fuel electrode anode (18) for a solid oxide fuel cell is made by presenting a solid oxide fuel cell having an electrolyte surface (15), mixing copper powder with solid oxide electrolyte in a mixing step (24, 44) to provide a spray feedstock (30,50) which is fed into a plasma jet (32, 52) of a plasma torch to melt the spray feed stock and propel it onto an electrolyte surface (34, 54) where the spray feed stock flattens into lamellae layer upon solidification, where the layer (38, 59) is an anode coating with greater than 35 vol. % based on solids volume.

  16. A Tri-Layer Proton-Conducting Electrolyte for Chemically Stable Operation in Solid Oxide Fuel Cells

    KAUST Repository

    Bi, Lei; Traversa, Enrico

    2013-01-01

    Two BaZr0.7Pr0.1Y0.2O3-δ (BZPY) layers were used to sandwich a BaCe0.8Y0.2O3-δ (BCY) layer to produce a tri-layer electrolyte consisting of BZPY/BCY/BZPY. The BZPY layers significantly improved the chemical stability of the BCY electrolyte layer, which was not stable when tested alone, suggesting that the BZPY layer effectively protected the BCY layer from CO2 reaction, which is the major problem of BCY-based materials. A fuel cell with this sandwiched electrolyte supported on a Ni-based composite anode showed a reasonable cell performance, reaching 185 mW cm-2 at 700 oC, in spite of the relatively large electrolyte thickness (about 65 µm).

  17. A Tri-Layer Proton-Conducting Electrolyte for Chemically Stable Operation in Solid Oxide Fuel Cells

    KAUST Repository

    Bi, Lei

    2013-10-07

    Two BaZr0.7Pr0.1Y0.2O3-δ (BZPY) layers were used to sandwich a BaCe0.8Y0.2O3-δ (BCY) layer to produce a tri-layer electrolyte consisting of BZPY/BCY/BZPY. The BZPY layers significantly improved the chemical stability of the BCY electrolyte layer, which was not stable when tested alone, suggesting that the BZPY layer effectively protected the BCY layer from CO2 reaction, which is the major problem of BCY-based materials. A fuel cell with this sandwiched electrolyte supported on a Ni-based composite anode showed a reasonable cell performance, reaching 185 mW cm-2 at 700 oC, in spite of the relatively large electrolyte thickness (about 65 µm).

  18. Synthesis, characterization and electrical properties of solid electrolyte for solid oxide fuel cell; Preparacao, caracterizacao e propriedades eletricas de eletrolito solido para celula a combustivel de oxido solido

    Energy Technology Data Exchange (ETDEWEB)

    Berton, Marco Antonio Coelho; Garcia, Carlos Mario; Matos, Jeferson Hrenechen [Instituto de Tecnologia para o Desenvolvimento (LACTEC), Curitiba, PR (Brazil)], Emails: felsky@latec.org.br, garcia@latec.org.br, jeferson.h@latec.org.br

    2010-04-15

    Solid electrolytes of BaCe{sub 08}Gd{sub O29} were prepared by the polymeric precursor method. X-ray diffraction data shows a single phase with orthorhombic crystalline structure. The densification process was followed by scanning electronic microscopy and apparent density measurements. The apparent density was developed for different temperatures of sintering, reaching > 96% for sintered temperature of 1550 {sup 0}C deg . The electrochemical impedance analysis was development in the temperature of 400-700 deg C, in air atmosphere at 700 deg C a value of 30,6 mS.cm{sup -1} was obtained. The results of conductivity have confirmed the gadolinium doped barium cerate has a great potential for use as solid electrolyte for intermediate temperature solid oxide fuel cell, at experimental controlled conditions. (author)

  19. Preparation and properties of poly(ethylene oxide) gel filled polypropylene separators and their corresponding gel polymer electrolytes for Li-ion batteries

    International Nuclear Information System (INIS)

    Li Hao; Ma Xiaoting; Shi Junli; Yao Zhikan; Zhu Baoku; Zhu Liping

    2011-01-01

    Poly(ethylene oxide) (PEO) filled polypropylene separators (GFPSs) are designed by means of thermal cross-linking of entrapped poly(ethylene glycol) methyl ether acrylate (PEGMEA) and poly(ethylene glycol) diacrylate (PEGDA) as gel constituents. The intrinsic properties of GFPS and their corresponding gel polymer electrolytes (GPE) are characterized by DSC, SEM, contact angle and electrochemical methods. It is found the stability of liquid electrolyte uptake in GPE could be improved obviously. For the GPE prepared from GFPS with filled polyether content of 14.3 wt%, the ionic conductivity could reach 1.12 x 10 -3 S cm -1 while the electrochemically stable window reach 5.0 V (vs. Li/Li + ). These primary results show great promise of this simple method to prepare GPE for practical application in lithium ion batteries.

  20. Preparation and properties of poly(ethylene oxide) gel filled polypropylene separators and their corresponding gel polymer electrolytes for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Li Hao; Ma Xiaoting; Shi Junli; Yao Zhikan [Department of Polymer Science and Engineering, Engineering Center of Membrane and Water Treatment, Key Laboratory of Macromolecule Synthesis and Functionalization (EMC), Zhejiang University, Hangzhou 310027 (China); Zhu Baoku, E-mail: zhubk@zju.edu.c [Department of Polymer Science and Engineering, Engineering Center of Membrane and Water Treatment, Key Laboratory of Macromolecule Synthesis and Functionalization (EMC), Zhejiang University, Hangzhou 310027 (China); Zhu Liping [Department of Polymer Science and Engineering, Engineering Center of Membrane and Water Treatment, Key Laboratory of Macromolecule Synthesis and Functionalization (EMC), Zhejiang University, Hangzhou 310027 (China)

    2011-02-15

    Poly(ethylene oxide) (PEO) filled polypropylene separators (GFPSs) are designed by means of thermal cross-linking of entrapped poly(ethylene glycol) methyl ether acrylate (PEGMEA) and poly(ethylene glycol) diacrylate (PEGDA) as gel constituents. The intrinsic properties of GFPS and their corresponding gel polymer electrolytes (GPE) are characterized by DSC, SEM, contact angle and electrochemical methods. It is found the stability of liquid electrolyte uptake in GPE could be improved obviously. For the GPE prepared from GFPS with filled polyether content of 14.3 wt%, the ionic conductivity could reach 1.12 x 10{sup -3} S cm{sup -1} while the electrochemically stable window reach 5.0 V (vs. Li/Li{sup +}). These primary results show great promise of this simple method to prepare GPE for practical application in lithium ion batteries.

  1. Reoxidation of uranium metal immersed in a Li2O-LiCl molten salt after electrolytic reduction of uranium oxide

    Science.gov (United States)

    Choi, Eun-Young; Jeon, Min Ku; Lee, Jeong; Kim, Sung-Wook; Lee, Sang Kwon; Lee, Sung-Jai; Heo, Dong Hyun; Kang, Hyun Woo; Jeon, Sang-Chae; Hur, Jin-Mok

    2017-03-01

    We present our findings that uranium (U) metal prepared by using the electrolytic reduction process for U oxide (UO2) in a Li2O-LiCl salt can be reoxidized into UO2 through the reaction between the U metal and Li2O in LiCl. Two salt types were used for immersion of the U metal: one was the salt used for electrolytic reduction, and the other was applied to the unused LiCl salts with various concentrations of Li2O and Li metal. Our results revealed that the degree of reoxidation increases with the increasing Li2O concentration in LiCl and that the presence of the Li metal in LiCl suppresses the reoxidation of the U metal.

  2. Thermodynamic properties of ternary oxides in the system Ba-Fe-O using solid-state electrochemical cells with oxide and fluoride ion conducting electrolytes

    Science.gov (United States)

    Rakshit, S. K.; Parida, S. C.; Singh, Ziley; Prasad, R.; Venugopal, V.

    2004-04-01

    The standard molar Gibbs energy of formations of BaFe 12O 19(s), BaFe 2O 4(s), Ba 2Fe 2O 5(s), Ba 3Fe 2O 6(s) and Ba 5Fe 2O 8(s) have been determined using solid-state electrochemical technique employing CaF 2(s) as an electrolyte. The reversible e.m.f. values have been measured in the temperature range from 970 to 1151 K. The oxygen chemical potential corresponding to three phase equilibria involving technologically important compound BaFe 12O 19(s) has been determined using solid-state electrochemical technique employing CSZ as an electrolyte from 1048 to 1221 K. The values of Δ fGm0( T) for the above ternary oxides are given by ΔfG m0( BaFe12O19, s)/ kJ mol -1(±0.6)=-5431.3+1.5317 (T/ K) (970⩽T/ K⩽1151) ΔfG m0( BaFe2O4, s)/ kJ mol -1(±1.3)=-1461.4+0.3745 (T/ K) (970⩽T/ K⩽1151) ΔfG m0( Ba2Fe2O5, s)/ kJ mol -1(±1.4)=-2038.3+0.4433 (T/ K) (970⩽T/ K⩽1149) ΔfG m0( Ba3Fe2O6, s)/ kJ mol -1(±1.5)=-2700.1+0.6090 (T/ K) (969⩽T/ K⩽1150) and ΔfG m0( Ba5Fe2O8, s)/ kJ mol -1(±1.6)=-3984.1+0.9300 (T/ K) (973⩽T/ K⩽1150) The uncertainty estimates for Δ fGm0 includes the standard deviation in the e.m.f. and uncertainty in the data taken from the literature. An isothermal oxygen potential diagram for the system Ba-Fe-O was constructed at 1100 K based on the thermodynamic data obtained in this study.

  3. Preparation and Characterization of Plasma-Sprayed Ultrafine Chromium Oxide Coatings

    International Nuclear Information System (INIS)

    Lin Feng; Jiang Xianliang; Yu Yueguang; Zeng Keli; Ren Xianjing; Li Zhenduo

    2007-01-01

    Ultrafine chromium oxide coatings were prepared by plasma spraying with ultrafine feedstock. Processing parameters of plasma spraying were optimized. Optical microscope (OM) was used to observe the microstructure of the ultrafine chromium oxide coatings. Scanning electron microscopy (SEM) was used to observe the morphology and particle size of ultrafine powder feedstock as well as to examine the microstructure of the chromium oxide coating. In addition, hardness and bonding strength of the ultrafine chromium oxide coatings were measured. The results showed that the optimized plasma spraying parameters were suitable for ultrafine chromium oxide coating and the properties and microstructure of the optimized ultrafine chromium oxide coating were superior compared to conventional chromium oxide wear resistant coatings

  4. Solid electrolytes in thermodynamic investigations. Investigation of oxygen pressure effect in Ar + O2 type mixtures on cell potentials with CaF2 electrolyte and oxide electrodes

    International Nuclear Information System (INIS)

    Levitskij, V.A.; Narchuk, N.B.; Kashkarova, S.L.

    1982-01-01

    An experimental test of the P'sub(Osub(2))=P''sub(Osub(2)) condition (P'sub(Osub(2)) and P''sub(Osub(2)) - oxygen pressure above the first and the second electrodes) necessary for reversible work of the cells is carried out with the (-)O 2 , Pt (CaZrO 3 , 0.18CaOx0.82ZrO 2 )CaF 2 CaF 2 CaHfO 3 , HfO 2 , CaF 2 Pt, O 2 (+) cell as an example. The equilibrium potentials of the given cell are shown to be independent from Psub(Osub(2)) value above both electrodes up to the O 2 pressure equal to approximately 1 Pa at Psub(gen.)=Psub(Osub(2))+Psub(Ar)=10sup(5) Pa. Thermodynamic parameters of the CaO+HfO 2 =CaHfO 3 reaction obtained from the E=f(T) dependence in argon atmosphere under Psub(Osub(2))=1-10sup(2) Pa well agree with analogous values determined for the same cell under Psub(Osub(2)) = 10 5 Pa. Comparison of the results obtained by the e. m. f. method with F - - ion electrolyte both in pure oxygen and in argon atmosphere under low Psub(Osub(2)) with the present literature data testify to perspectives of using the cells of this type under controlled low Psub(Osub(2)) values for thermodynamic investigations

  5. Production of nitric oxide using a microwave plasma torch and its application to fungal cell differentiation

    International Nuclear Information System (INIS)

    Na, Young Ho; Kang, Min-Ho; Cho, Guang Sup; Choi, Eun Ha; Park, Gyungsoon; Uhm, Han Sup; Kumar, Naresh

    2015-01-01

    The generation of nitric oxide by a microwave plasma torch is proposed for its application to cell differentiation. A microwave plasma torch was developed based on basic kinetic theory. The analytical theory indicates that nitric oxide density is nearly proportional to oxygen molecular density and that the high-temperature flame is an effective means of generating nitric oxide. Experimental data pertaining to nitric oxide production are presented in terms of the oxygen input in units of cubic centimeters per minute. The apparent length of the torch flame increases as the oxygen input increases. The various levels of nitric oxide are observed depending on the flow rate of nitrogen gas, the mole fraction of oxygen gas, and the microwave power. In order to evaluate the potential of nitric oxide as an activator of cell differentiation, we applied nitric oxide generated from the microwave plasma torch to a model microbial cell (Neurospora crassa: non-pathogenic fungus). Germination and hyphal differentiation of fungal cells were not dramatically changed but there was a significant increase in spore formation after treatment with nitric oxide. In addition, the expression level of a sporulation related gene acon-3 was significantly elevated after 24 h upon nitric oxide treatment. Increase in the level of nitric oxide, nitrite and nitrate in water after nitric oxide treatment seems to be responsible for activation of fungal sporulation. Our results suggest that nitric oxide generated by plasma can be used as a possible activator of cell differentiation and development. (paper)

  6. Further optimization of barium cerate properties via co-doping strategy for potential application as proton-conducting solid oxide fuel cell electrolyte

    Science.gov (United States)

    Wang, Shuai; Shen, Jianxing; Zhu, Zhiwen; Wang, Zhihao; Cao, Yanxin; Guan, Xiaoli; Wang, Yueyue; Wei, Zhaoling; Chen, Meina

    2018-05-01

    Yttrium-doped BaCeO3 is one of the most promising electrolyte candidates for solid oxide fuel cells because of its high ionic conductivity. Nd and Y co-doped BaCeO3 strategy is adopted for the further optimization of Y-doped BaCeO3 electrolyte properties. X-ray diffraction results indicate that the structure of BaCe0.8Y0.2-xNdxO3-δ (x = 0, 0.05, 0.1, 0.15) with orthorhombic perovskite phase becomes more symmetric with increasing Nd concentration. The scanning electron microscope observation demonstrates that the densification and grain size of the sintered pellets significantly enhance with the increase of Nd doping level. Whether in dry and humid hydrogen or air, the increase of Nd dopant firstly increases the conductivities of BaCe0.8Y0.2-xNdxO3-δ (x = 0, 0.05, 0.1, 0.15) and then decrease them after reaching the peak value at x = 0.05. Electrochemical impedance spectra at 350 °C can distinguish clearly the contribution of grain and grain boundary to total conductivity and the highest conductivity of BaCe0.8Y0.15Nd0.05O3-δ ascribes to the decrease in bulk and grain boundary resistances due to the synergistic effect of Nd and Y doping. The anode-supported single cell with BaCe0.8Y0.15Nd0.05O3-δ electrolyte shows an encouraging peak power density of 660 mW cm-2 at 700 °C, suggesting that BaCe0.8Y0.15Nd0.05O3-δ is a potential electrolyte material for the highly-efficient proton-conducting solid oxide fuel cell.

  7. Oxidation of Inconel 625 superalloy upon treatment with oxygen or hydrogen plasma at high temperature

    Czech Academy of Sciences Publication Activity Database

    Vesel, A.; Drenik, A.; Elersic, K.; Mozetič, M.; Kovač, J.; Gyergyek, T.; Stöckel, Jan; Varju, Jozef; Pánek, Radomír; Balat-Pichelin, M.

    2014-01-01

    Roč. 305, June (2014), s. 674-682 ISSN 0169-4332 R&D Projects: GA MŠk(CZ) LM2011021 Institutional support: RVO:61389021 Keywords : Inconel * Oxidation * High temperature * Oxygen plasma * Hydrogen plasma Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.711, year: 2014 https://www.sciencedirect.com/science/article/pii/S0169433214007119

  8. Electrolyte materials - Issues and challenges

    International Nuclear Information System (INIS)

    Balbuena, Perla B.

    2014-01-01

    Electrolytes are vital components of an electrochemical energy storage device. They are usually composed of a solvent or mixture of solvents and a salt or a mixture of salts which provide the appropriate environment for ionic conduction. One of the main issues associated with the selection of a proper electrolyte is that its electronic properties have to be such that allow a wide electrochemical window - defined as the voltage range in which the electrolyte is not oxidized or reduced - suitable to the battery operating voltage. In addition, electrolytes must have high ionic conductivity and negligible electronic conductivity, be chemically stable with respect to the other battery components, have low flammability, and low cost. Weak stability of the electrolyte against oxidation or reduction leads to the formation of a solid-electrolyte interphase (SEI) layer at the surface of the cathode and anode respectively. Depending on the materials of the electrolyte and those of the electrode, the SEI layer may be composed by combinations of organic and inorganic species, and it may exert a passivating role. In this paper we discuss the current status of knowledge about electrolyte materials, including non-aqueous liquids, ionic liquids, solid ceramic and polymer electrolytes. We also review the basic knowledge about the SEI layer formation, and challenges for a rational design of stable electrolytes

  9. Effect of Samarium Oxide on the Electrical Conductivity of Plasma-Sprayed SOFC Anodes

    Science.gov (United States)

    Panahi, S. N.; Samadi, H.; Nemati, A.

    2016-10-01

    Solid oxide fuel cells (SOFCs) are rapidly becoming recognized as a new alternative to traditional energy conversion systems because of their high energy efficiency. From an ecological perspective, this environmentally friendly technology, which produces clean energy, is likely to be implemented more frequently in the future. However, the current SOFC technology still cannot meet the demands of commercial applications due to temperature constraints and high cost. To develop a marketable SOFC, suppliers have tended to reduce the operating temperatures by a few hundred degrees. The overall trend for SOFC materials is to reduce their service temperature of electrolyte. Meanwhile, it is important that the other components perform at the same temperature. Currently, the anodes of SOFCs are being studied in depth. Research has indicated that anodes based on a perovskite structure are a more promising candidate in SOFCs than the traditional system because they possess more favorable electrical properties. Among the perovskite-type oxides, SrTiO3 is one of the most promising compositions, with studies demonstrating that SrTiO3 exhibits particularly favorable electrical properties in contrast with other perovskite-type oxides. The main purpose of this article is to describe our study of the effect of rare-earth dopants with a perovskite structure on the electrical behavior of anodes in SOFCs. Sm2O3-doped SrTiO3 synthesized by a solid-state reaction was coated on substrate by atmospheric plasma spray. To compare the effect of the dopant on the electrical conductivity of strontium titanate, different concentrations of Sm2O3 were used. The samples were then investigated by x-ray diffraction, four-point probe at various temperatures (to determine the electrical conductivity), and a scanning electron microscope. The study showed that at room temperature, nondoped samples have a higher electrical resistance than doped samples. As the temperature was increased, the electrical

  10. Synthesis and characterization of nanoporous anodic oxide film on aluminum in H3PO4 + KMnO4 electrolyte mixture at different anodization conditions

    Science.gov (United States)

    Verma, Naveen; Jindal, Jitender; Singh, Krishan Chander; Mari, Bernabe

    2016-04-01

    The micro structural properties of nanoporous anodic oxide film formed in H3PO4 were highly influenced by addition of a low concentration of KMnO4 (0.0005 M) in 1 M H3PO4 solution. The KMnO4 as additive enhanced the growth rate of oxide film formation as well as thickness of pore walls. Furthermore the growth rate was found increased with increase in applied current density. The increase in temperature and lack of stirring during anodization causes the thinness of pore wall which leads to increase in pore volume. With the decrease in concentration of H3PO4 in anodizing electrolyte from 1M to 0.3 M, keeping all other conditions constant, the decrease in porosity was observed. This might be due to the dissolution of aluminium oxide film in highly concentrated acidic solution.

  11. Removing of oxides from Fe-Ni alloys by hydrogen plasma treatment

    International Nuclear Information System (INIS)

    Vesel, A.; Drenik, A.; Mozetic, M.

    2007-01-01

    Plasma wall interaction is one of the key issues in fusion research for ITER application. The first-wall materials in tokamaks and in other high temperature plasma reactors are subject to and to continuous degradation due to the ion bombardment. Furthermore the release of the eroded wall material leads to their redeposition to other parts of the fusion reactor and they can be even transported into the core plasma where they cause dilution of the plasma fuel and cooling of the plasma itself. One possible solution for removal of deposits formed during operation of the fusion devices is oxygen plasma treatment. A drawback of the oxygen plasma is that it causes formation of oxides on the surface of the materials. These oxides can be reduced by further hydrogen plasma treatment. A study on reduction of an oxide layer from Fe-Ni alloys was performed. The samples were exposed to low pressure weakly ionized hydrogen plasma for different periods. A density of hydrogen plasma was 8x10 15 m -3 , an electron temperature was 6 eV, and a degree of dissociation was about 30%. After plasma treatment the samples were analyzed by Auger Electron Spectroscopy (AES). The results showed that the complete reduction of an initial oxide layer with the thickness of about 30 nm occurred after 20 s of exposure to hydrogen plasma, when AES showed no more oxygen on the surface of Fe-Ni alloy. During the exposure of the samples to the plasma their temperature was measured. The temperature first rised with time, reached the maximum value, and than dropped as soon as the layer of an oxide on the surface was reduced. (author)

  12. Role of plasma activation in tailoring the nanostructure of multifunctional oxides thin films

    Energy Technology Data Exchange (ETDEWEB)

    Giangregorio, Maria M.; Losurdo, Maria; Capezzuto, Pio [Institute of Inorganic Methodologies and Plasmas, IMIP-CNR, and Department of Chemistry, University of Bari, via Orabona, 4-70125 Bari (Italy); Bruno, Giovanni [Institute of Inorganic Methodologies and Plasmas, IMIP-CNR, and Department of Chemistry, University of Bari, via Orabona, 4-70125 Bari (Italy)], E-mail: giovanni.bruno@ba.imip.cnr.it

    2009-03-01

    Potential of O{sub 2} remote plasmas for improving structural, morphological and optical properties of various multifunctional oxides thin films both during plasma assisted growth as well as by post-growth treatments is discussed. In particular, an O{sub 2} remote plasma metalorganic chemical vapor deposition (RP-MOCVD) route is presented for tailoring the structural, morphological and optical properties of Er{sub 2}O{sub 3} and ZnO films. Furthermore, post-growth room-temperature remote O{sub 2} plasma treatments of indium-tin-oxides (ITO) films are demonstrated to be effective in improving morphology of ITO films.

  13. Atmospheric pressure plasma enhanced chemical vapor deposition of zinc oxide and aluminum zinc oxide

    International Nuclear Information System (INIS)

    Johnson, Kyle W.; Guruvenket, Srinivasan; Sailer, Robert A.; Ahrenkiel, S. Phillip; Schulz, Douglas L.

    2013-01-01

    Zinc oxide (ZnO) and aluminum-doped zinc oxide (AZO) thin films were deposited via atmospheric pressure plasma enhanced chemical vapor deposition. A second-generation precursor, bis(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)(N,N′-diethylethylenediamine) zinc, exhibited significant vapor pressure and good stability at one atmosphere where a vaporization temperature of 110 °C gave flux ∼ 7 μmol/min. Auger electron spectroscopy confirmed that addition of H 2 O to the carrier gas stream mitigated F contamination giving nearly 1:1 metal:oxide stoichiometries for both ZnO and AZO with little precursor-derived C contamination. ZnO and AZO thin film resistivities ranged from 14 to 28 Ω·cm for the former and 1.1 to 2.7 Ω·cm for the latter. - Highlights: • A second generation precursor was utilized for atmospheric pressure film growth. • Addition of water vapor to the carrier gas stream led to a marked reduction of ZnF 2 . • Carbonaceous contamination from the precursor was minimal

  14. Theory of electroreduction of solid oxide electrolytes. Kinetics and mechanism of the galvanostatic process with blocking cathodes

    International Nuclear Information System (INIS)

    Chebotin, V.N.; Brainin, M.I.; Lukach, Yu. S.; Pakhnutov, I.A.; Solov'eva, L.M.

    1986-01-01

    This paper discusses dc flow through cells with MO 2 + MeOΓ solid electrolyte (M = Zr, Hf, Ce, or Th; Me = Ca, Sr, Sc, Y, or lanthanides), a blocking cathode, and a reversible anode which leads to departures of the electrolytes from stoichiometry in the direction of oxygen deficiency. A nonlinear differential equation of the diffusion type describes the degree of this departure and the n-type electronic conductivity which is proportional to it, as functions of the coordinate and time. The electrolyte's electronic conductivity increases with time near the cathode, and approaches a limiting value that is proportional to the current being passed. The electronic conductivity falls off exponentially with increasing distance from the cathode; this changes to a linear fall as a function of time

  15. High Ionic Conductivity of Composite Solid Polymer Electrolyte via In Situ Synthesis of Monodispersed SiO2 Nanospheres in Poly(ethylene oxide).

    Science.gov (United States)

    Lin, Dingchang; Liu, Wei; Liu, Yayuan; Lee, Hye Ryoung; Hsu, Po-Chun; Liu, Kai; Cui, Yi

    2016-01-13

    High ionic conductivity solid polymer electrolyte (SPE) has long been desired for the next generation high energy and safe rechargeable lithium batteries. Among all of the SPEs, composite polymer electrolyte (CPE) with ceramic fillers has garnered great interest due to the enhancement of ionic conductivity. However, the high degree of polymer crystallinity, agglomeration of ceramic fillers, and weak polymer-ceramic interaction limit the further improvement of ionic conductivity. Different from the existing methods of blending preformed ceramic particles with polymers, here we introduce an in situ synthesis of ceramic filler particles in polymer electrolyte. Much stronger chemical/mechanical interactions between monodispersed 12 nm diameter SiO2 nanospheres and poly(ethylene oxide) (PEO) chains were produced by in situ hydrolysis, which significantly suppresses the crystallization of PEO and thus facilitates polymer segmental motion for ionic conduction. In addition, an improved degree of LiClO4 dissociation can also be achieved. All of these lead to good ionic conductivity (1.2 × 10(-3) S cm(-1) at 60 °C, 4.4 × 10(-5) S cm(-1) at 30 °C). At the same time, largely extended electrochemical stability window up to 5.5 V can be observed. We further demonstrated all-solid-state lithium batteries showing excellent rate capability as well as good cycling performance.

  16. High-performance electrodes for reduced temperature solid oxide fuel cells with doped lanthanum gallate electrolyte. Pt. 2. La(Sr)CoO{sub 3} cathode

    Energy Technology Data Exchange (ETDEWEB)

    Inagaki, Toru; Yoshida, Hiroyuki [The Kansai Electric Power, Hyogo (Japan); Miura, Kazuhiro [Kanden Kakou, Hyogo (Japan); Maric, Radenka; Ohara, Satoshi; Zhang, Xinge; Mukai, Kazuo; Fukui, Takehisa [Japan Fine Ceramics Center, Nagoya (Japan)

    2000-03-01

    The reduced temperature solid oxide fuel cell (SOFC) with 0.5 mm thick La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 3-{alpha}} (LSGM) electrolyte, La{sub 0.6}Sr{sub 0.4}CoO{sub 3-{delta}} (LSCo) cathode, and Ni-(CeO{sub 2}){sub 0.8}(SmO{sub 1.5}){sub 0.2} (SDC) cermet anode showed an excellent initial performance, and high maximum power density, 0.47 W/cm{sup 2}, at 800 C. The results were comparable to those for the conventional SOFC with yttria-stabilized zirconia (YSZ) electrolyte, La(Sr)MnO{sub 3}-YSZ cathode and Ni-YSZ cermet anode at 1000 C. Using an LSCo powder prepared by spray pyrolysis, and selecting appropriate sintering temperatures, the lowest cathodic polarization of about 25 mV at 300 mA/cm{sup 2} was measured for a cathode prepared by sintering at 1000 C. Life time cell test results, however, showed that the polarization of the LSCo cathode increased with operating time. From EPMA results, this behavior was considered to be related to the interdiffusion of the elements at the cathode/electrolyte interface. Calcination of LSCo powder could be a possible way to suppress this interdiffusion at the interface. (orig.)

  17. High-performance electrodes for reduced temperature solid oxide fuel cells with doped lanthanum gallate electrolyte. II. La(Sr)CoO 3 cathode

    Science.gov (United States)

    Inagaki, Toru; Miura, Kazuhiro; Yoshida, Hiroyuki; Maric, Radenka; Ohara, Satoshi; Zhang, Xinge; Mukai, Kazuo; Fukui, Takehisa

    The reduced temperature solid oxide fuel cell (SOFC) with 0.5 mm thick La 0.9Sr 0.1Ga 0.8Mg 0.2O 3- α (LSGM) electrolyte, La 0.6Sr 0.4CoO 3- δ (LSCo) cathode, and Ni-(CeO 2) 0.8(SmO 1.5) 0.2 (SDC) cermet anode showed an excellent initial performance, and high maximum power density, 0.47 W/cm 2, at 800°C. The results were comparable to those for the conventional SOFC with yttria-stabilized zirconia (YSZ) electrolyte, La(Sr)MnO 3-YSZ cathode and Ni-YSZ cermet anode at 1000°C. Using an LSCo powder prepared by spray pyrolysis, and selecting appropriate sintering temperatures, the lowest cathodic polarization of about 25 mV at 300 mA/cm 2 was measured for a cathode prepared by sintering at 1000°C. Life time cell test results, however, showed that the polarization of the LSCo cathode increased with operating time. From EPMA results, this behavior was considered to be related to the interdiffusion of the elements at the cathode/electrolyte interface. Calcination of LSCo powder could be a possible way to suppress this interdiffusion at the interface.

  18. Advanced oxide powders processing based on cascade plasma

    International Nuclear Information System (INIS)

    Solonenko, O P; Smirnov, A V

    2014-01-01

    Analysis of the potential advantages offered to thermal spraying and powder processing by the implementation of plasma torches with inter-electrode insert (IEI) or, in other words, cascade plasma torches (CPTs) is presented. The paper provides evidence that the modular designed single cathode CPT helps eliminate the following major disadvantages of conventional plasma torches: plasma parameters drifting, 1-5 kHz pulsing of plasma flow, as well as excessive erosion of electrodes. More stable plasma results in higher quality, homogeneity and reproducibility of plasma sprayed coatings and powders treated. In addition, CPT offers an extremely wide operating window, which allows better control of plasma parameters, particle dwell time and, consequently, particle temperature and velocity within a wide range by generating high enthalpy quasi-laminar plasmas, medium enthalpy transient plasmas, as well as relatively low enthalpy turbulent plasmas. Stable operation, flexibility with plasma gases as well as wide operating window of CPT should help significantly improve the existing plasma spraying processes and coatings, and also help develop new advanced technologies

  19. Influence of C3H8O3 in the electrolyte on characteristics and corrosion resistance of the microarc oxidation coatings formed on AZ91D magnesium alloy surface

    International Nuclear Information System (INIS)

    Wu Di; Liu Xiangdong; Lu Kai; Zhang Yaping; Wang Huan

    2009-01-01

    Ceramic coatings were fabricated on AZ91D Mg-alloy substrate by microarc oxidation in Na 2 SiO 3 -NaOH-Na 2 EDTA electrolytes with and without C 3 H 8 O 3 addition. The effects of different concentrations of C 3 H 8 O 3 contained in the electrolyte on coatings thickness were investigated. The surface morphologies, RMS roughness, phase compositions and corrosion resistance property of the ceramic coatings were analyzed by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and electrochemical corrosion test respectively. It is found that the addition of C 3 H 8 O 3 into silicate electrolyte leads to increase of the unit-area adsorptive capacity of the negative ions at anode-electrolyte interface and thus improves the compactness and corrosion resistance of the MAO coating. The coating thickness decreases gradually with the increase of concentrations of C 3 H 8 O 3 in the electrolyte. The oxide coating formed in base electrolyte containing 4 mL/L C 3 H 8 O 3 exhibits the best surface appearance, the lowest surface RMS roughness (174 nm) and highest corrosion resistance. In addition, both ceramic coatings treated in base electrolyte with and without C 3 H 8 O 3 are mainly composed of periclase MgO and forsterite Mg 2 SiO 4 phase, but no diffraction peak of Mg phase is found in the patterns.

  20. Suppression of interfacial reactions between Li4Ti5O12 electrode and electrolyte solution via zinc oxide coating

    International Nuclear Information System (INIS)

    Han, Cuiping; He, Yan-Bing; Li, Hongfei; Li, Baohua; Du, Hongda; Qin, Xianying; Kang, Feiyu

    2015-01-01

    Graphical abstract: The Li 4 Ti 5 O 12 (LTO) based batteries have severe gassing behavior due to the strong interfacial reactions between LTO and the electrolyte solution, which hampers the practical application of LTO in high power LIBs. The ZnO coating on LTO particles as a barrier layer can effectively suppress the interfacial reactions between LTO and the electrolyte solution. Simultaneously, the ZnO coating significantly reduces the charge-transfer resistance and increases the lithium ion diffusion coefficient, which leads to great improvement of rate and cyclic performance of LTO electrode. - Highlights: • A ZnO coating layer was constructed on the LTO particles by a chemical process as a barrier layer between LTO and surrounding electrolyte solution. • The ZnO coating can effectively stabilize the electrode/electrolyte interface and suppress interfacial reactions between LTO and electrolyte solution. • The ZnO coating can improve the electronic conductivity and lithium ion diffusion coefficient, which contributes to a great improvement in cyclic and high rate capabilities of LTO electrode. • The ZnO coating on LTO may be an effective method to solve the gassing behavior of LTO based battery and promote its wide application in lithium ion power battery. - Abstract: Li 4 Ti 5 O 12 (LTO) based batteries have severe gassing behavior during charge/discharge and storage process. The interfacial reactions between LTO and electrolyte solution may be the main reason. In this work, the LTO spinel particles are modified with ZnO coating using a chemical process to reduce the surface reactivity of LTO particles. Results show that the ZnO coating can effectively stabilize the electrode/electrolyte interface and suppress the formation of a solid electrolyte interface (SEI) film. Simultaneously, this ZnO modification can improve the electronic conductivity and lithium ion diffusion coefficient, which contributes to a great improvement in cyclic and high rate

  1. Oxide-Based Composite Electrolytes Using Na3Zr2Si2PO12/Na3PS4 Interfacial Ion Transfer.

    Science.gov (United States)

    Noi, Kousuke; Nagata, Yuka; Hakari, Takashi; Suzuki, Kenji; Yubuchi, So; Ito, Yusuke; Sakuda, Atsushi; Hayashi, Akitoshi; Tatsumisago, Masahiro

    2018-05-31

    All-solid-state sodium batteries using Na 3 Zr 2 Si 2 PO 12 (NASICON) solid electrolytes are promising candidates for safe and low-cost advanced rechargeable battery systems. Although NASICON electrolytes have intrinsically high sodium-ion conductivities, their high sintering temperatures interfere with the immediate development of high-performance batteries. In this work, sintering-free NASICON-based composites with Na 3 PS 4 (NPS) glass ceramics were prepared to combine the high grain-bulk conductivity of NASICON and the interfacial formation ability of NPS. Before the composite preparation, the NASICON/NPS interfacial resistance was investigated by modeling the interface between the NASICON sintered ceramic and the NPS glass thin film. The interfacial ion-transfer resistance was very small above room temperature; the area-specific resistances at 25 and 100 °C were 15.8 and 0.40 Ω cm 2 , respectively. On the basis of this smooth ion transfer, NASICON-rich (70-90 wt %) NASICON-NPS composite powders were prepared by ball-milling fine powders of each component. The composite powders were well-densified by pressing at room temperature. Scanning electron microscopy observation showed highly dispersed sub-micrometer NASICON grains in a dense NPS matrix to form closed interfaces between the oxide and sulfide solid electrolytes. The composite green (unfired) compacts with 70 and 80 wt % NASICON exhibited high total conductivities at 100 °C of 1.1 × 10 -3 and 6.8 × 10 -4 S cm -1 , respectively. An all-solid-state Na 15 Sn 4 /TiS 2 cell was constructed using the 70 wt % NASICON composite electrolyte by the uniaxial pressing of the powder materials, and its discharge properties were evaluated at 100 °C. The cell showed the reversible capacities of about 120 mAh g -1 under the current density of 640 μA cm -2 . The prepared oxide-based composite electrolytes were thus successfully applied in all-solid-state sodium rechargeable batteries without sintering.

  2. Stages of polymer transformation during remote plasma oxidation (RPO) at atmospheric pressure

    Science.gov (United States)

    Luan, P.; Oehrlein, G. S.

    2018-04-01

    The interaction of cold temperature plasma sources with materials can be separated into two types: ‘direct’ and ‘remote’ treatments. Compared to the ‘direct’ treatment which involves energetic charged species along with short-lived, strongly oxidative neutral species, ‘remote’ treatment by the long-lived weakly oxidative species is less invasive and better for producing uniformly treated surfaces. In this paper, we examine the prototypical case of remote plasma oxidation (RPO) of polymer materials by employing a surface micro-discharge (in a N2/O2 mixture environment) treatment on polystyrene. Using material characterization techniques including real-time ellipsometry, x-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy, the time evolution of polymer film thickness, refractive index, surface, and bulk chemical composition were evaluated. These measurements revealed three consecutive stages of polymer transformation, i.e. surface adsorption and oxidation, bulk film permeation and thickness expansion followed by the material removal as a result of RPO. By correlating the observed film thickness changes with simultaneously obtained chemical information, we found that the three stages were due to the three effects of weakly oxidative species on polymers: (1) surface oxidation and nitrate (R-ONO2) chemisorption, (2) bulk oxidation, and (3) etching. Our results demonstrate that surface adsorption and oxidation, bulk oxidation, and etching can all happen during one continuous plasma treatment. We show that surface nitrate is only adsorbed on the top few nanometers of the polymer surface. The polymer film expansion also provided evidence for the diffusion and reaction of long-lived plasma species in the polymer bulk. Besides, we found that the remote plasma etched surface was relatively rich in O-C=O (ester or carboxylic acid). These findings clarify the roles of long-lived weakly oxidative plasma species on polymers and advance

  3. Effects of Hypertonic Saline Solution on Clinical Parameters, Serum Electrolytes and Plasma Volume in the Treatment of Haemorrhagic Septicaemia in Buffaloes

    Directory of Open Access Journals (Sweden)

    M. Arif Zafar*, G. Muhammad, Zafar Iqbal1 and M. Riaz2

    2010-04-01

    Full Text Available This study was conducted to determine the efficacy of hypertonic saline solution (HSS along with antibiotic (ceftiofur HCl and non-steroidal anti-inflammatory drug (ketoprofen in the treatment of haemorrhagic septicaemia in buffaloes. For this purpose, 50 buffaloes suffering from haemorrhagic septicaemia were randomly divided in two equal groups A and B. Group A served as control and was treated with ceftiofur HCl (IM and ketoprofen (IV @ 6 and 2 mg/Kg BW, respectively, for five days. Buffaloes of group B were administered with rapid intravenous infusion of hypertonic saline solution (7.5% NaCl @ 4 ml/Kg BW once in combination with ceftiofur HCl and ketoprofen. Animals were monitored for 24 hours after initiation of treatment. Clinical parameters, serum electrolytes, plasma volume and survival index were recorded at different intervals after treatment. Survival rate (80% in group B was significantly higher (P<0.05 than 48% in group A. The heart rate and respiration rate recovered more effectively in the buffaloes administered with treatment protocol B. Plasma volume was 98% which was almost normal within 24 hours after the infusion of hypertonic saline solution to the animals of group B. It was concluded from the study that hypertonic saline solution as an adjunct to antibiotic and a non-steroidal anti-inflammatory drug more efficiently improved respiration and heart rates and effectively restored plasma volume in resuscitating the buffaloes from haemorrhagic septicaemia than the conventional treatment.

  4. Nickel exposure and plasma levels of biomarkers for assessing oxidative stress in nickel electroplating workers.

    Science.gov (United States)

    Tsao, Yu-Chung; Gu, Po-Wen; Liu, Su-Hsun; Tzeng, I-Shiang; Chen, Jau-Yuan; Luo, Jiin-Chyuan John

    2017-07-01

    The mechanism of nickel-induced pathogenesis remains elusive. To examine effects of nickel exposure on plasma oxidative and anti-oxidative biomarkers. Biomarker data were collected from 154 workers with various levels of nickel exposure and from 73 controls. Correlations between nickel exposure and oxidative and anti-oxidative biomarkers were determined using linear regression models. Workers with a exposure to high nickel levels had significantly lower levels of anti-oxidants (glutathione and catalase) than those with a lower exposure to nickel; however, only glutathione showed an independent association after multivariable adjustment. Exposure to high levels of nickel may reduce serum anti-oxidative capacity.

  5. Investigation of Obtaining Highly-Strong Wire of 12X18H10T-Steei by Drawing Method with Electrolyte-Plasma Surface Machining

    Directory of Open Access Journals (Sweden)

    L. A. Isaevich

    2005-01-01

    Full Text Available Purpose of the paper is to investigate technology of strain hardening of corrosion-resistant austenitic 12X18H10T steel by drawing method using electrolyte-plasma machining (EPM as an auxiliary operation. Structure and properties of material surface layer after drawing have been examined. It has been ascertained that there are scores and micro-cracks on the material surface that make it difficult to carry out subsequent drawing drafts.In order to eliminate these drawbacks it is proposed to apply EPM between drawing stages. The developed drawing modes using EPM allow to reduce number of drafts while obtaining special hard- drawn wire and improve service life of the tool.

  6. Self-propagating high-temperature synthesis of La(Sr)Ga(Mg)O{sub 3-{delta}} for electrolyte of solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, Hiroyuki [Center for Advanced Research of Energy Conversion Materials, Hokkaido University, Sapporo 060-8628 (Japan); Enoki, Makiko [Department of Applied Chemistry, Faculty of Engineering, Kyusyu University, Fukuoka 812-8581 (Japan); Ishihara, Tatsumi [Department of Applied Chemistry, Faculty of Engineering, Kyusyu University, Fukuoka 812-8581 (Japan); Akiyama, Tomohiro [Center for Advanced Research of Energy Conversion Materials, Hokkaido University, Sapporo 060-8628 (Japan)]. E-mail: takiyama@eng.hokudai.ac.jp

    2007-03-14

    This paper describes self-propagating high-temperature synthesis (SHS) of an electrolyte for solid oxide fuel (SOFC), in comparison to a conventional solid-state reaction method (SRM). Doped-lanthanum gallate: La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 3-{delta}} (LSGM9182) and LSGM9173 as the SOFC electrolyte, was prepared by the SHS and sintered at different temperatures, for measuring the electrical conductivity of the sintered LSGM and the power generating performance at 1073 K, in comparison to the SRM. In the SHS, the LSGM powders with smaller size were obtained and easily sintered at the 100 K-lower temperature, 1673 K, than in the SRM. Most significantly, the electrical conductivity of the sintered LSGM9182 was as high as 0.11 S cm{sup -1} and its maximum power density was a value of 245 mW cm{sup -2} in the cell configuration of Ni/LSGM9182 (0.501 mm in thickness)/Sm{sub 0.5}Sr{sub 0.5}CoO{sub 3}. The conclusion was that the proposed SHS-sintering method with many benefits of minimizing the energy requirement and the processing time in the production, easing temperature restriction for the sintering, and improving the electrolyte performance up to a conventional level is practicable for producing the LSGM-electrolyte of SOFC at an intermediate-temperature application.

  7. Effect of Na2WO4 in Electrolyte on Microstructure and Tribological Behavior of Micro-arc Oxidation Coatings on Ti2AlNb Alloy

    Directory of Open Access Journals (Sweden)

    LIU Xiao-hui

    2018-02-01

    Full Text Available Micro-arc oxidation (MAO ceramic coatings were prepared on Ti2AlNb alloy in silicate/phosphate electrolytes with different concentrations of Na2WO4. The influence of Na2WO4 on the coating growth process, coating structure and composition was analyzed by SEM, XRD and XPS. The tribological behavior of MAO coatings was evaluated by the ball-disc wear test. The results show that the growth rate of MAO coating in electrolyte without Na2WO4 is only 0.08μm/min, meanwhile, the coating is loose and rough, and "networks" connecting with big pores exist on the coating surface.The main phase compositions of this coating are rutile TiO2, anatase TiO2, Al2O3, and Nb2O5. The addition of Na2WO4 in the electrolyte shortens the time before sparking of Ti2AlNb alloy, increases the growth rate of the coating, improves the uniformity of coating and meanwhile, a small amount of WO3 is introduced in the coating. Besides, MAO coatings formed in the participation of Na2WO4 have better wear resistance. Severe abrasive wear occurs when the test is made on Ti2AlNb alloy with Si3N4, the friction coefficient reaches 0.5-0.7. Both the friction coefficient and wear rate decrease obviously when Ti2AlNb is treated by MAO. The friction coefficient and wear rate of MAO coating prepared in the electrolyte with 4g/L Na2WO4 are 0.24 and 6.2×10-4mm3/(N·m, respectively. Only "fish scales" caused by fatigue wear appears on the coating surface.

  8. Investigation of the Reversible Lithiation of an Oxide Free Aluminum Anode by a LiBH4 Solid State Electrolyte

    Directory of Open Access Journals (Sweden)

    Jason A. Weeks

    2017-11-01

    Full Text Available In this study, we analyze and compare the physical and electrochemical properties of an all solid-state cell utilizing LiBH4 as the electrolyte and aluminum as the active anode material. The system was characterized by galvanostatic lithiation/delithiation, cyclic voltammetry (CV, X-ray diffraction (XRD, energy dispersive X-ray spectroscopy (EDS, Raman spectroscopy, electrochemical impedance spectroscopy (EIS, and scanning electron microscopy (SEM. Constant current cycling demonstrated that the aluminum anode can be reversibly lithiated over multiple cycles utilizing a solid-state electrolyte. An initial capacity of 895 mAh/g was observed and is close to the theoretical capacity of aluminum. Cyclic voltammetry of the cell was consistent with the constant current cycling data and showed that the reversible lithiation/delithiation of aluminum occurs at 0.32 V and 0.38 V (vs. Li+/Li respectively. XRD of the aluminum anode in the initial and lithiated state clearly showed the formation of a LiAl (1:1 alloy. SEM-EDS was utilized to examine the morphological changes that occur within the electrode during cycling. This work is the first example of reversible lithiation of aluminum in a solid-state cell and further emphasizes the robust nature of the LiBH4 electrolyte. This demonstrates the possibility of utilizing other high capacity anode materials with a LiBH4 based solid electrolyte in all-solid-state batteries.

  9. Enhancement of corrosion resistance for plasma nitrided AISI 4140 steel by plain air plasma post-oxidizing

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jiqiang; Liu, Han; Ye, Xuemei [Jiangsu Key Laboratory of Materials Surface Technology, Changzhou University, Changzhou 213164 (China); Chai, Yating [Materials Research and Education Center, Auburn University, AL 36849 (United States); Hu, Jing, E-mail: jinghoo@126.com [Jiangsu Key Laboratory of Materials Surface Technology, Changzhou University, Changzhou 213164 (China); Materials Research and Education Center, Auburn University, AL 36849 (United States)

    2015-05-25

    Highlights: • Plain air was primarily used for plasma post-oxidation for AISI 4140 steel. • A thin iron oxide layer composed of Fe{sub 3}O{sub 4} to Fe{sub 2}O{sub 3} was formed on top of the compound layer. • The ratio of Fe{sub 3}O{sub 4} to Fe{sub 2}O{sub 3} was closely related to the post-oxidizing conditions. • Post-oxidizing at 673 K for 60 min brought out highest ratio of Fe{sub 3}O{sub 4} to Fe{sub 2}O{sub 3} and optimum corrosion resistance. - Abstract: Plasma post-oxidizing was conducted immediately after plasma nitriding in the same equipment for AISI 4140 steel, and plain air was used as the oxygen bearing gas. The cross-sectional microstructures of the treated samples were observed by optical metallography and scanning electron microcopy (SEM), and the thickness of compound layer was measured accordingly. The phases were determined by X-ray diffraction (XRD), corrosion resistance was evaluated by electrochemical polarization, and the surface morphology before and after polarization test was also observed by SEM. Meanwhile, standard Gibbs free energy of the oxidation reactions existed in Fe–O system was calculated. The results show that a thin iron oxide layer composed of magnetite (Fe{sub 3}O{sub 4}) and hematite (Fe{sub 2}O{sub 3}) is formed on top of the compound layer during plasma post-oxidizing process, and the ratio of magnetite (Fe{sub 3}O{sub 4}) to hematite (Fe{sub 2}O{sub 3}) is depended on plasma post-oxidizing temperature and time. Highest ratio of Fe{sub 3}O{sub 4} to Fe{sub 2}O{sub 3} is obtained while post-oxidizing at 673 K for 60 min due to lower standard Gibbs free energy and appropriate forming rate for the formation of Fe{sub 3}O{sub 4} at this temperature. The thin oxide layer brings out significant enhancement of corrosion resistance, especially at higher ratios of Fe{sub 3}O{sub 4} to Fe{sub 2}O{sub 3}, due to the dense and adherent characteristic of Fe{sub 3}O{sub 4} oxide. Surface images of the post-oxidizing specimen

  10. Ferritic oxide dispersion strengthened alloys by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Allahar, Kerry N., E-mail: KerryAllahar@boisestate.edu [Materials and Science Engineering Department, Boise State University, 1910 University Blvd., Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Blvd., Idaho Falls, ID 83401 (United States); Burns, Jatuporn [Materials and Science Engineering Department, Boise State University, 1910 University Blvd., Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Blvd., Idaho Falls, ID 83401 (United States); Jaques, Brian [Materials and Science Engineering Department, Boise State University, 1910 University Blvd., Boise, ID 83725 (United States); Wu, Y.Q. [Materials and Science Engineering Department, Boise State University, 1910 University Blvd., Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Blvd., Idaho Falls, ID 83401 (United States); Charit, Indrajit [Department of Chemical and Materials Engineering, University of Idaho, McClure Hall Room 405D, Moscow, ID 83844 (United States); Cole, James [Idaho National Laboratory, Idaho Falls, ID 83401 (United States); Butt, Darryl P. [Materials and Science Engineering Department, Boise State University, 1910 University Blvd., Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Blvd., Idaho Falls, ID 83401 (United States)

    2013-11-15

    Spark plasma sintering (SPS) was used to consolidate a Fe–16Cr–3Al (wt.%) powder that was mechanically alloyed with Y{sub 2}O{sub 3} and Ti powders to produce 0.5 Y{sub 2}O{sub 3} and 0.5 Y{sub 2}O{sub 3}–1Ti powders. The effects of mechanical alloying and sintering conditions on the microstructure, relative density and hardness of the sintered oxide dispersion strengthened (ODS) alloys are presented. Scanning electron microscopy indicated a mixed fine-grain and coarse-grain microstructure that was attributed to recrystallization and grain growth during sintering. Analysis of the transmission electron microscopy (TEM) and atom probe tomography (APT) data identified Y–O and Y–O–Ti nanoclusters. Elemental ratios of these nanoclusters were consistent with that observed in hot-extruded ODS alloys. The influence of Ti was to refine the grains as well as the nanoclusters with there being greater number density and smaller sizes of the Y–O–Ti nanoclusters as compared to the Y–O nanoclusters. This resulted in the Ti-containing samples being harder than the Ti-free alloys. The hardness of the alloys with the Y–O–Ti nanoclusters was insensitive to sintering time while smaller hardness values were associated with longer sintering times for the alloys with the Y–O nanoclusters. Pressures greater than 80 MPa are recommended for improved densification as higher sintering temperatures and longer sintering times at 80 MPa did not improve the relative density beyond 97.5%.

  11. Ascorbic acid protects lipids in human plasma and low-density lipoprotein against oxidative damage

    Energy Technology Data Exchange (ETDEWEB)

    Frei, B. (Department of Nutrition, Harvard School of Public Health, Boston, MA (Unites States))

    1991-12-01

    The authors exposed human blood plasma and low-density lipoprotein (LDL) to many different oxidative challenges and followed the temporal consumption of endogenous antioxidants in relation to the initiation of oxidative damage. Under all types of oxidizing conditions, ascorbic acid completely protects lipids in plasma and LDL against detectable peroxidative damage as assessed by a specific and highly sensitive assay for lipid peroxidation. Ascorbic acid proved to be superior to the other water-soluble plasma antioxidants bilirubin, uric acid, and protein thiols as well as to the lipoprotein-associated antioxidants alpha-tocopherol, ubiquinol-10, lycopene, and beta-carotene. Although these antioxidants can lower the rate of detectable lipid peroxidation, they are not able to prevent its initiation. Only ascorbic acid is reactive enough to effectively intercept oxidants in the aqueous phase before they can attack and cause detectable oxidative damage to lipids.

  12. Concurrent aggregation and transport of graphene oxide in saturated porous media: Roles of temperature, cation type, and electrolyte concentration.

    Science.gov (United States)

    Wang, Mei; Gao, Bin; Tang, Deshan; Yu, Congrong

    2018-04-01

    Simultaneous aggregation and retention of nanoparticles can occur during their transport in porous media. In this work, the concurrent aggregation and transport of GO in saturated porous media were investigated under the conditions of different combinations of temperature, cation type (valence), and electrolyte concentration. Increasing temperature (6-24 °C) at a relatively high electrolyte concentration (i.e., 50 mM for Na + , 1 mM for Ca 2+ , 1.75 mM for Mg 2+ , and 0.03 and 0.05 mM for Al 3+ ) resulted in enhanced GO retention in the porous media. For instance, when the temperature increased from 6 to 24 °C, GO recovery rate decreased from 31.08% to 6.53% for 0.03 mM Al 3+ and from 27.11% to 0 for 0.05 mM Al 3+ . At the same temperature, increasing cation valence and electrolyte concentration also promoted GO retention. Although GO aggregation occurred in the electrolytes during the transport, the deposition mechanisms of GO retention in the media depended on cation type (valence). For 50 mM Na + , surface deposition via secondary minima was the dominant GO retention mechanism. For multivalent cation electrolytes, GO aggregation was rapid and thus other mechanisms such as physical straining and sedimentation also played important roles in controlling GO retention in the media. After passing through the columns, the GO particles in the effluents showed better stability with lower initial aggregation rates. This was probably because less stable GO particles with lower surface charge densities in the porewater were filtered by the porous media, resulting in more stable GO particle with higher surface charge densities in the effluents. An advection-dispersion-reaction model was applied to simulate GO breakthrough curves and the simulations matched all the experimental data well. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Plasma-enhanced chemical vapor deposition of aluminum oxide using ultrashort precursor injection pulses

    NARCIS (Netherlands)

    Dingemans, G.; Sanden, van de M.C.M.; Kessels, W.M.M.

    2012-01-01

    An alternative plasma-enhanced chemical vapor deposition (PECVD) method is developed and applied for the deposition of high-quality aluminum oxide (AlOx) films. The PECVD method combines a continuous plasma with ultrashort precursor injection pulses. We demonstrate that the modulation of the

  14. Combining plasma gasification and solid oxide cell technologies in advanced power plants for waste to energy and electric energy storage applications.

    Science.gov (United States)

    Perna, Alessandra; Minutillo, Mariagiovanna; Lubrano Lavadera, Antonio; Jannelli, Elio

    2018-03-01

    The waste to energy (WtE) facilities and the renewable energy storage systems have a strategic role in the promotion of the "eco-innovation", an emerging priority in the European Union. This paper aims to propose advanced plant configurations in which waste to energy plants and electric energy storage systems from intermittent renewable sources are combined for obtaining more efficient and clean energy solutions in accordance with the "eco-innovation" approach. The advanced plant configurations consist of an electric energy storage (EES) section based on a solid oxide electrolyzer (SOEC), a waste gasification section based on the plasma technology and a power generation section based on a solid oxide fuel cell (SOFC). The plant configurations differ for the utilization of electrolytic hydrogen and oxygen in the plasma gasification section and in the power generation section. In the first plant configuration IAPGFC (Integrated Air Plasma Gasification Fuel Cell), the renewable oxygen enriches the air stream, that is used as plasma gas in the gasification section, and the renewable hydrogen is used to enrich the anodic stream of the SOFC in the power generation section. In the second plant configuration IHPGFC (Integrated Hydrogen Plasma Gasification Fuel Cell) the renewable hydrogen is used as plasma gas in the plasma gasification section, and the renewable oxygen is used to enrich the cathodic stream of the SOFC in the power generation section. The analysis has been carried out by using numerical models for predicting and comparing the systems performances in terms of electric efficiency and capability in realizing the waste to energy and the electric energy storage of renewable sources. Results have highlighted that the electric efficiency is very high for all configurations (35-45%) and, thanks to the combination with the waste to energy technology, the storage efficiencies are very attractive (in the range 72-92%). Copyright © 2017 Elsevier Ltd. All rights

  15. Formation of Nitrogen Oxides in an Apokamp-Type Plasma Source

    Science.gov (United States)

    Sosnin, É. A.; Goltsova, P. A.; Panarin, V. A.; Skakun, V. S.; Tarasenko, V. F.; Didenko, M. V.

    2017-08-01

    Using optical and chemical processes, the composition of the products of decay of the atmospheric-pressure non-equilibrium plasma is determined in a pulsed, high-voltage discharge in the modes of apokampic and corona discharges. It is shown that the products of decay primarily contain nitrogen oxides NO x, and in the mode of the corona discharge - ozone. Potential applications of this source of plasma are discussed with respect to plasma processing of the seeds of agricultural crops.

  16. TREATMENT OF REFRACTORY OXIDES IN HF-PLASMA REACTORS

    OpenAIRE

    Bakhvalov , A.; Dresvin , S.; Levitskaya , T.; Paskalov , G.; Philippov , A.

    1990-01-01

    Results of theoretical and experimental studies of SiO2 NaBSi, MgO, W and some other materials treatment in induction type high-frequency plasma under atmospheric pressure are presented. Key study objective - optimization of plasma installation operating modes with maximum efficiency -0.6 -0.7 ; spheroidization extent -90-99%, size of treated particles 1-500 mkm. Diagnostics of thermophysical and gasodynamical plasma reactor specifications has been presented.

  17. Production of oxide-metal P/M composites using pulsed plasma heating

    Energy Technology Data Exchange (ETDEWEB)

    Blinkov, I.V.; Manukhin, A.V.; Ostapovich, A.O.; Pavlov, IU.A.

    1987-08-01

    The possibility of producing oxide-metal P/M composites using plasma generated by a pulsed discharge is investigated experimentally for the system Al/sup 2/O/sub 3/-Ni. It is found that Al/sup 2/O/sub 3/ metallization in plasma is accompanied by spheroidization; changes in the physicomechanical properties of the Al/sup 2/O/sub 3/-Ni composite during plasma treatment are examined. The characteristic features of the process associated with the effect of pulsed energy on the disperse flow of the oxide-metal mixture are discussed. 7 references.

  18. Development of Lithium Stuffed Garnet-Type Oxide Solid Electrolytes with High Ionic Conductivity for Application to All-Solid-State Batteries

    Directory of Open Access Journals (Sweden)

    Ryoji Inada

    2016-07-01

    Full Text Available All-solid-state lithium-ion battery (LiB is expected as one of the next generation energy storage devices because of their high energy density, high safety and excellent cycle stability. Although oxide-based solid electrolyte materials have rather lower conductivity and poor deformability than sulfide-based one, they have other advantages such as their chemical stability and easiness for handling. Among the various oxide-based SEs, lithium stuffed garnet-type oxide with the formula of Li7La3Zr2O12 (LLZ have been widely studied because of their high conductivity above 10-4 Scm-1 at room temperature, excellent thermal performance and stability against Li metal anode.Here, we present our recent progress for the development of garnet-type solid electrolytes with high conductivity by simultaneous substitution of Ta5+ into Zr4+ site and Ba2+ into La3+ site in LLZ. Li+ concentration was fixed to 6.5 per chemical formulae, so that the formulae of our Li garnet-type oxide is expressed as Li6.5La3-xBaxZr1.5-xTa0.5+xO12 (LLBZT and Ba contents x are changed from 0 to 0.3. As results, all LLBZT samples have cubic garnet structure without containing any secondary phases. The lattice parameters of LLBZT decrease with increasing Ba2+ contents x < 0.10 while increase with x from 0.10 to 0.30, possibly due to the simultaneous change of Ba2+ and Ta5+ substitution levels. Relative densities of LLBZT are in the range between 89% and 93% and not influenced so much by the compositions. From AC impedance spectroscopy measurements, the total (bulk + grain conductivity at 27ºC of LLBZT shows its maximum value of 8.34 x 10-4 S cm-1 at x = 0.10, which is slightly higher than the conductivity (= 7.94 x 10-4 S cm-1 of LLZT without substituting Ba (x = 0. Activation energy of the conductivity tends to become lower by Ba substation, while excess Ba substitution degrades the conductivity in LLBZT. LLBZT has wide electrochemical potential window of 0-6 V vs. Li+/Li and

  19. Surface Modification of NiTi Alloy via Cathodic Plasma Electrolytic Deposition and its Effect on Ni Ion Release and Osteoblast Behaviors

    International Nuclear Information System (INIS)

    Yan Ying; Cai Kaiyong; Yang Weihu; Liu Peng

    2013-01-01

    To reduce Ni ion release and improve biocompatibility of NiTi alloy, the cathodic plasma electrolytic deposition (CPED) technique was used to fabricate ceramic coating onto a NiTi alloy surface. The formation of a coating with a rough and micro-textured surface was confirmed by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy, respectively. An inductively coupled plasma mass spectrometry test showed that the formed coating significantly reduced the release of Ni ions from the NiTi alloy in simulated body fluid. The influence of CPED treated NiTi substrates on the biological behaviors of osteoblasts, including cell adhesion, cell viability, and osteogenic differentiation function (alkaline phosphatase), was investigated in vitro. Immunofluorescence staining of nuclei revealed that the CPED treated NiTi alloy was favorable for cell growth. Osteoblasts on CPED modified NiTi alloy showed greater cell viability than those for the native NiTi substrate after 4 and 7 days cultures. More importantly, osteoblasts cultured onto a modified NiTi sample displayed significantly higher differentiation levels of alkaline phosphatase. The results suggested that surface functionalization of NiTi alloy with ceramic coating via the CPED technique was beneficial for cell proliferation and differentiation. The approach presented here is useful for NiTi implants to enhance bone osteointegration and reduce Ni ion release in vitro

  20. Surface Modification of NiTi Alloy via Cathodic Plasma Electrolytic Deposition and its Effect on Ni Ion Release and Osteoblast Behaviors

    Science.gov (United States)

    Yan, Ying; Cai, Kaiyong; Yang, Weihu; Liu, Peng

    2013-07-01

    To reduce Ni ion release and improve biocompatibility of NiTi alloy, the cathodic plasma electrolytic deposition (CPED) technique was used to fabricate ceramic coating onto a NiTi alloy surface. The formation of a coating with a rough and micro-textured surface was confirmed by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy, respectively. An inductively coupled plasma mass spectrometry test showed that the formed coating significantly reduced the release of Ni ions from the NiTi alloy in simulated body fluid. The influence of CPED treated NiTi substrates on the biological behaviors of osteoblasts, including cell adhesion, cell viability, and osteogenic differentiation function (alkaline phosphatase), was investigated in vitro. Immunofluorescence staining of nuclei revealed that the CPED treated NiTi alloy was favorable for cell growth. Osteoblasts on CPED modified NiTi alloy showed greater cell viability than those for the native NiTi substrate after 4 and 7 days cultures. More importantly, osteoblasts cultured onto a modified NiTi sample displayed significantly higher differentiation levels of alkaline phosphatase. The results suggested that surface functionalization of NiTi alloy with ceramic coating via the CPED technique was beneficial for cell proliferation and differentiation. The approach presented here is useful for NiTi implants to enhance bone osseointegration and reduce Ni ion release in vitro.

  1. Isothermal oxidation of metallic coatings deposited by a water-stabilized plasma gun

    Czech Academy of Sciences Publication Activity Database

    Voleník, Karel; Nop, P.; Kopřiva, P.; Kolman, Blahoslav Jan; Dubský, Jiří

    2006-01-01

    Roč. 44, č. 1 (2006), s. 41-48 ISSN 0023-432X R&D Projects: GA ČR(CZ) GA106/03/0710 Institutional research plan: CEZ:AV0Z20430508 Keywords : plasma spraying * metallic coatings * oxidation tests * oxidation kinetics * oxide structure * element distribution Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 1.138, year: 2006

  2. The kinetics of nonequilibrium chain plasma-chemical oxidation in heterogeneous media

    International Nuclear Information System (INIS)

    Deminskii, M.A.; Potapkin, B.V.; Rusanov, V.D.

    1994-01-01

    The kinetics of oxidation of low-impurity components in air mixtures under heterogeneous conditions was studied. The principal kinetic features of the process were determined on the basis of theoretical analysis of plasma-chemical oxidation in heterogeneous media. The analysis also showed that low concentrations of impurities in liquid aerosol particles can be efficiently oxidized via a chain process induced by reactive species formed in the gas

  3. Water surface coverage effects on reactivity of plasma oxidized Ti films

    International Nuclear Information System (INIS)

    Pranevicius, L.; Pranevicius, L.L.; Vilkinis, P.; Baltaragis, S.; Gedvilas, K.

    2014-01-01

    Highlights: • The reactivity of Ti films immersed in water vapor plasma depends on the surface water coverage. • The adsorbed water monolayers are disintegrated into atomic constituents on the hydrophilic TiO 2 under plasma radiation. • The TiO 2 surface covered by water multilayer loses its ability to split adsorbed water molecules under plasma radiation. - Abstract: The behavior of the adsorbed water on the surface of thin sputter deposited Ti films maintained at room temperature was investigated in dependence on the thickness of the resulting adsorbed water layer, controllably injecting water vapor into plasma. The surface morphology and microstructure were used to characterize the surfaces of plasma treated titanium films. Presented experimental results showed that titanium films immersed in water vapor plasma at pressure of 10–100 Pa promoted the photocatalytic activity of overall water splitting. The surfaces of plasma oxidized titanium covered by an adsorbed hydroxyl-rich island structure water layer and activated by plasma radiation became highly chemically reactive. As water vapor pressure increased up to 300–500 Pa, the formed water multilayer diminished the water oxidation and, consequently, water splitting efficiency decreased. Analysis of the experimental results gave important insights into the role an adsorbed water layer on surface of titanium exposed to water vapor plasma on its chemical activity and plasma activated electrochemical processes, and elucidated the surface reactions that could lead to the split of water molecules

  4. Synthesis of tungsten oxide, silver, and gold nanoparticles by radio frequency plasma in water

    International Nuclear Information System (INIS)

    Hattori, Yoshiaki; Nomura, Shinfuku; Mukasa, Shinobu; Toyota, Hiromichi; Inoue, Toru; Usui, Tomoya

    2013-01-01

    Highlights: •RF plasma in water was used for nanoparticle synthesis. •Nanoparticles were produced from erosion of metallic electrode. •Rectangular and spherical tungsten oxide nanoparticles were produced. •No oxidations of the silver and gold spherical nanoparticles were produced. -- Abstract: A process for synthesis of nanoparticles using plasma in water generated by a radio frequency of 27.12 MHz is proposed. Tungsten oxide, silver, and gold nanoparticles were produced at 20 kPa through erosion of a metallic electrode exposed to plasma. Characterization of the produced nanoparticles was carried out by XRD, absorption spectrum, and TEM. The nanoparticle sizes were compared with those produced by a similar technique using plasma in liquid

  5. The tunable plasma synthesis of Pt-reduced graphene oxide nanocomposites

    Directory of Open Access Journals (Sweden)

    Yulong Ma

    2017-06-01

    Full Text Available Herein, we have developed Pt-plasma reduced graphene oxide (Pt/P-rGO catalysts displaying high overpotentials for methanol oxidation reaction (MOR through facile and tunable plasma treatments. We provide insight into the improved performance of these catalysts by combining electrochemical measurements with microscopic and spectroscopic characterization techniques. The analysis results showed that the Pt nanoparticles (NPs were successfully deposited on P-rGO. The deposition and uniformity of Pt NPs were influenced by tuning the discharge power of the plasma. The catalytic performance towards the methanol oxidation reaction is investigated. The Pt/P-rGO NPs composites under 100 W show the best electrocatalytic activity. These results were vital to the further application of graphene-based metal nanocomposites synthesized by plasma technology.

  6. Single-ion triblock copolymer electrolytes based on poly(ethylene oxide) and methacrylic sulfonamide blocks for lithium metal batteries

    Science.gov (United States)

    Porcarelli, Luca; Aboudzadeh, M. Ali; Rubatat, Laurent; Nair, Jijeesh R.; Shaplov, Alexander S.; Gerbaldi, Claudio; Mecerreyes, David

    2017-10-01

    Single-ion conducting polymer electrolytes represent the ideal solution to reduce concentration polarization in lithium metal batteries (LMBs). This paper reports on the synthesis and characterization of single-ion ABA triblock copolymer electrolytes comprising PEO and poly(lithium 1-[3-(methacryloyloxy)propylsulfonyl]-1-(trifluoromethylsulfonyl)imide) blocks, poly(LiMTFSI). Block copolymers are prepared by reversible addition-fragmentation chain transfer polymerization, showing low glass transition temperature (-55 to 7 °C) and degree of crystallinity (51-0%). Comparatively high values of ionic conductivity are obtained (up to ≈ 10-4 S cm-1 at 70 °C), combined with a lithium-ion transference number close to unity (tLi+ ≈ 0.91) and a 4 V electrochemical stability window. In addition to these promising features, solid polymer electrolytes are successfully tested in lithium metal cells at 70 °C providing long lifetime up to 300 cycles, and stable charge/discharge cycling at C/2 (≈100 mAh g-1).

  7. Solid electrolyte fuel cells

    Science.gov (United States)

    Isaacs, H. S.

    Progress in the development of functioning solid electrolyte fuel cells is summarized. The solid electrolyte cells perform at 1000 C, a temperature elevated enough to indicate high efficiencies are available, especially if the cell is combined with a steam generator/turbine system. The system is noted to be sulfur tolerant, so coal containing significant amounts of sulfur is expected to yield satisfactory performances with low parasitic losses for gasification and purification. Solid oxide systems are electrically reversible, and are usable in both fuel cell and electrolysis modes. Employing zirconium and yttrium in the electrolyte provides component stability with time, a feature not present with other fuel cells. The chemical reactions producing the cell current are reviewed, along with materials choices for the cathodes, anodes, and interconnections.

  8. Effect of plasma power on reduction of printable graphene oxide thin films on flexible substrates

    Science.gov (United States)

    Banerjee, Indrani; Mahapatra, Santosh K.; Pal, Chandana; Sharma, Ashwani K.; Ray, Asim K.

    2018-05-01

    Room temperature hydrogen plasma treatment on solution processed 300 nm graphene oxide (GO) films on flexible indium tin oxide (ITO) coated polyethylene terephthalate (PET) substrates has been performed by varying the plasma power between 20 W and 60 W at a constant exposure time of 30 min with a view to examining the effect of plasma power on reduction of GO. X-ray powder diffraction (XRD) and Raman spectroscopic studies show that high energy hydrogen species generated in the plasma assist fast exfoliation of the oxygenated functional groups present in the GO samples. Significant decrease in the optical band gap is observed from 4.1 eV for untreated samples to 0.5 eV for 60 W plasma treated samples. The conductivity of the films treated with 60 W plasma power is estimated to be six orders of magnitude greater than untreated GO films and this enhancement of conductivity on plasma reduction has been interpreted in terms of UV-visible absorption spectra and density functional based first principle computational calculations. Plasma reduction of GO/ITO/PET structures can be used for efficiently tuning the electrical and optical properties of reduced graphene oxide (rGO) for flexible electronics applications.

  9. Room temperature plasma oxidation: A new process for preparation of ultrathin layers of silicon oxide, and high dielectric constant materials

    International Nuclear Information System (INIS)

    Tinoco, J.C.; Estrada, M.; Baez, H.; Cerdeira, A.

    2006-01-01

    In this paper we present basic features and oxidation law of the room temperature plasma oxidation (RTPO), as a new process for preparation of less than 2 nm thick layers of SiO 2 , and high-k layers of TiO 2 . We show that oxidation rate follows a potential law dependence on oxidation time. The proportionality constant is function of pressure, plasma power, reagent gas and plasma density, while the exponent depends only on the reactive gas. These parameters are related to the physical phenomena occurring inside the plasma, during oxidation. Metal-Oxide-Semiconductor (MOS) capacitors fabricated with these layers are characterized by capacitance-voltage, current-voltage and current-voltage-temperature measurements. Less than 2.5 nm SiO 2 layers with surface roughness similar to thermal oxide films, surface state density below 3 x 10 11 cm -2 and current density in the expected range for each corresponding thickness, were obtained by RTPO in a parallel-plate reactor, at 180 mW/cm 2 and pressure range between 9.33 and 66.5 Pa (0.07 and 0.5 Torr) using O 2 and N 2 O as reactive gases. MOS capacitors with TiO 2 layers formed by RTPO of sputtered Ti layers are also characterized. Finally, MOS capacitors with stacked layers of TiO 2 over SiO 2 , both layers obtained by RTPO, were prepared and evaluated to determine the feasibility of the use of TiO 2 as a candidate for next technology nodes

  10. Distribution of electrolytes in a flow battery

    Science.gov (United States)

    Darling, Robert Mason; Smeltz, Andrew; Junker, Sven Tobias; Perry, Michael L.

    2017-12-26

    A method of determining a distribution of electrolytes in a flow battery includes providing a flow battery with a fixed amount of fluid electrolyte having a common electrochemically active specie, a portion of the fluid electrolyte serving as an anolyte and a remainder of the fluid electrolyte serving as a catholyte. An average oxidation state of the common electrochemically active specie is determined in the anolyte and the catholyte and, responsive to the determined average oxidation state, a molar ratio of the common electrochemically active specie between the anolyte and the catholyte is adjusted to increase an energy discharge capacity of the flow battery for the determined average oxidation state.

  11. Characteristics of ceramic oxide nanoparticles synthesized using radio frequency produced thermal plasma

    International Nuclear Information System (INIS)

    Dhamale, Gayatri D.; Mathe, V.L.; Bhoraskar, S.V.; Ghorui, S.

    2015-01-01

    Thermal plasma devices with their unique processing capabilities due to extremely high temperature and steep temperature gradient play an important role in synthesis of ultrafine powders in the range of 100nm or less. High temperature gas phase synthesis in Radio Frequency (RF) thermal plasma reactor is an attractive route for mass production of refractory nanoparticles, especially in the case of rare earth oxides. Here we report synthesis of Yttrium Oxide (Y_2O_3), Neodymium Oxide (Nd_2O_3) and Aluminum Oxide (Al_2O_3) in an inductively coupled radio frequency thermal plasma reactor. Synthesized nanoparticles find wide application in various fields like gate dielectrics, photocatalytic applications, laser devices and photonics. Nano sized Yttrium oxide, Neodymium Oxide and Aluminum oxide powders were separately synthesized in an RF plasma reactor starting with micron sized irregular shaped precursor powders. The system was operated at 3MHz in atmospheric pressure at different power levels. Synthesized powders were scrapped out from different deposition locations inside the reactor and characterized for their phase, morphology, particle size, crystallinity and other characteristic features. Highly crystalline nature of the synthesized particles, narrow size distribution, location dependent phase formation, and distinct variation in the inherent defect states compared to the bulk are some of the important characteristic features observed

  12. Morphology and performances of the anodic oxide films on Ti6Al4V alloy formed in alkaline-silicate electrolyte with aminopropyl silane addition under low potential

    International Nuclear Information System (INIS)

    Chen, Jiali; Wang, Jinwei; Yuan, Hongye

    2013-01-01

    Oxide films on Ti6Al4V alloy are prepared using sodium hydroxide–sodium silicate as the base electrolyte with addition of aminopropyl trimethoxysilane (APS) as additive by potentiostatic anodizing under 10 V. APS is incorporated into the films during anodizing and the surface morphology of the oxide films is changed from particle stacked to honeycomb-like porous surfaces as shown by scanning electron microscopy (SEM) with Energy Disperse Spectroscopy (EDX). The surface roughness and aminopropyl existence on the oxide films result in their differences in wettability as tested by the surface profile topography and contact angle measurements. The anti-abrasive ability of the anodic films is improved with the addition of APS due to its toughening effects and serving as lubricants in the ceramic oxide films as measured by ball-on-disk friction test. Also, potentiodynamic corrosion test proves that their anticorrosive ability in 3.5 wt.% NaCl is greatly improved as reflected by their much lower corrosion current (I corr ) and higher corrosion potential (E corr ) than those of the substrate.

  13. Morphology and performances of the anodic oxide films on Ti6Al4V alloy formed in alkaline-silicate electrolyte with aminopropyl silane addition under low potential

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jiali; Wang, Jinwei, E-mail: wangjw@ustb.edu.cn; Yuan, Hongye

    2013-11-01

    Oxide films on Ti6Al4V alloy are prepared using sodium hydroxide–sodium silicate as the base electrolyte with addition of aminopropyl trimethoxysilane (APS) as additive by potentiostatic anodizing under 10 V. APS is incorporated into the films during anodizing and the surface morphology of the oxide films is changed from particle stacked to honeycomb-like porous surfaces as shown by scanning electron microscopy (SEM) with Energy Disperse Spectroscopy (EDX). The surface roughness and aminopropyl existence on the oxide films result in their differences in wettability as tested by the surface profile topography and contact angle measurements. The anti-abrasive ability of the anodic films is improved with the addition of APS due to its toughening effects and serving as lubricants in the ceramic oxide films as measured by ball-on-disk friction test. Also, potentiodynamic corrosion test proves that their anticorrosive ability in 3.5 wt.% NaCl is greatly improved as reflected by their much lower corrosion current (I{sub corr}) and higher corrosion potential (E{sub corr}) than those of the substrate.

  14. Aging and its circumvention in rf-plasma oxidized Pb-alloy Josephson junctions

    International Nuclear Information System (INIS)

    Wada, M.; Nakano, J.

    1987-01-01

    The aging phenomenon of Pb-alloy Josephson junctions is investigated and an effective method of circumventing it is presented. Junctions consist of Pb-alloy electrodes and a tunneling barrier formed by rf-plasma oxidation of the Pb-alloy. First, aging and annealing-driven change in normal tunneling resistance are compared to verify the usage of annealing as an experimental method for simulation and acceleration of aging. Next, process variables affecting the annealing change in junction characteristics are examined and their influence is described. The importance of the oxide-base electrode interface is confirmed and that of the counterelectrode-oxide interface is experimentally shown. Furthermore, possible changes in the oxide itself are discussed. Finally, on the basis of these studies, rf-plasma oxidation in a CO 2 atmosphere is employed and proven to be an effective method for circumventing the annealing change in the junction characteristics

  15. To immobilize polyethylene glycol-borate ester/lithium fluoride in graphene oxide/poly(vinyl alcohol for synthesizing new polymer electrolyte membrane of lithium-ion batteries

    Directory of Open Access Journals (Sweden)

    Y. F. Huang

    2017-01-01

    Full Text Available Polymer electrolyte membranes (PEMs are potentially applicable in lithium-ion batteries with high safety, low cost and good performance. Here, to take advantages of ionic conductivity and selectivity of borate