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Sample records for anodic surface treatment

  1. Anodized dental implant surface

    Directory of Open Access Journals (Sweden)

    Sunil Kumar Mishra

    2017-01-01

    Full Text Available Purpose: Anodized implants with moderately rough surface were introduced around 2000. Whether these implants enhanced biologic effect to improve the environment for better osseointegration was unclear. The purpose of this article was to review the literature available on anodized surface in terms of their clinical success rate and bone response in patients till now. Materials and Methods: A broad electronic search of MEDLINE and PubMed databases was performed. A focus was made on peer-reviewed dental journals. Only articles related to anodized implants were included. Both animal and human studies were included. Results: The initial search of articles resulted in 581 articles on anodized implants. The initial screening of titles and abstracts resulted in 112 full-text papers; 40 animal studies, 16 studies on cell adhesion and bacterial adhesion onto anodized surfaced implants, and 47 human studies were included. Nine studies, which do not fulfill the inclusion criteria, were excluded. Conclusions: The long-term studies on anodized surface implants do favor the surface, but in most of the studies, anodized surface is compared with that of machined surface, but not with other surfaces commercially available. Anodized surface in terms of clinical success rate in cases of compromised bone and immediately extracted sockets has shown favorable success.

  2. Electrically Conductive Anodized Aluminum Surfaces

    Science.gov (United States)

    Nguyen, Trung Hung

    2006-01-01

    Anodized aluminum components can be treated to make them sufficiently electrically conductive to suppress discharges of static electricity. The treatment was conceived as a means of preventing static electric discharges on exterior satin-anodized aluminum (SAA) surfaces of spacecraft without adversely affecting the thermal-control/optical properties of the SAA and without need to apply electrically conductive paints, which eventually peel off in the harsh environment of outer space. The treatment can also be used to impart electrical conductivity to anodized housings of computers, medical electronic instruments, telephoneexchange equipment, and other terrestrial electronic equipment vulnerable to electrostatic discharge. The electrical resistivity of a typical anodized aluminum surface layer lies between 10(exp 11) and 10(exp 13) Omega-cm. To suppress electrostatic discharge, it is necessary to reduce the electrical resistivity significantly - preferably to anodized surface becomes covered and the pores in the surface filled with a transparent, electrically conductive metal oxide nanocomposite. Filling the pores with the nanocomposite reduces the transverse electrical resistivity and, in the original intended outer-space application, the exterior covering portion of the nanocomposite would afford the requisite electrical contact with the outer-space plasma. The electrical resistivity of the nanocomposite can be tailored to a value between 10(exp 7) and 10(exp 12) Omega-cm. Unlike electrically conductive paint, the nanocomposite becomes an integral part of the anodized aluminum substrate, without need for adhesive bonding material and without risk of subsequent peeling. The electrodeposition process is compatible with commercial anodizing production lines. At present, the electronics industry uses expensive, exotic, electrostaticdischarge- suppressing finishes: examples include silver impregnated anodized, black electroless nickel, black chrome, and black copper. In

  3. Enhancing dye-sensitized solar cell efficiency by anode surface treatments

    International Nuclear Information System (INIS)

    Chang, Chao-Hsuan; Lin, Hsin-Han; Chen, Chin-Cheng; Hong, Franklin C.-N.

    2014-01-01

    In this study, titanium substrates treated with HF solution and KOH solution sequentially forming micro- and nano-structures were used for the fabrication of flexible dye-sensitized solar cells (DSSCs). After wet etching treatments, the titanium substrates were then exposed to the O 2 plasma treatment and further immersed in titanium tetrachloride (TiCl 4 ) solution. The process conditions for producing a very thin TiO 2 blocking layer were studied, in order to avoid solar cell current leakage for increasing the solar cell efficiency. Subsequently, TiO 2 nanoparticles were spin-coated on Ti substrates with varied thickness. The dye-sensitized solar cells on the titanium substrates were subjected to simulate AM 1.5 G irradiation of 100 mW/cm 2 using backside illumination mode. Surface treatments of Ti substrate and TiO 2 anode were found to play a significant role in improving the efficiency of DSSC. The efficiencies of the backside illumination solar cells were raised from 4.6% to 7.8% by integrating these surface treatments. - Highlights: • The flexible dye-sensitized solar cell (DSSC) device can be fabricated. • Many effective surface treatment methods to improve DSSC efficiency are elucidated. • The efficiency is dramatically enhanced by integrating surface treatment methods. • The back-illuminated DSSC efficiency was raised from 4.6% to 7.8%

  4. Physicochemical state of the nanotopographic surface of commercially pure titanium following anodization-hydrothermal treatment reveals significantly improved hydrophilicity and surface energy profiles.

    Science.gov (United States)

    Takebe, Jun; Ito, Shigeki; Miura, Shingo; Miyata, Kyohei; Ishibashi, Kanji

    2012-01-01

    A method of coating commercially pure titanium (cpTi) implants with a highly crystalline, thin hydroxyapatite (HA) layer using discharge anodic oxidation followed by hydrothermal treatment (Spark discharged Anodic oxidation treatment ; SA-treated cpTi) has been reported for use in clinical dentistry. We hypothesized that a thin HA layer with high crystallinity and nanostructured anodic titanium oxide film on such SA-treated cpTi implant surfaces might be a crucial function of their surface-specific potential energy. To test this, we analyzed anodic oxide (AO) cpTi and SA-treated cpTi disks by SEM and AFM. Contact angles and surface free energy of each disk surface was measured using FAMAS software. High-magnification SEM and AFM revealed the nanotopographic structure of the anodic titanium oxide film on SA-treated cpTi; however, this was not observed on the AO cpTi surface. The contact angle and surface free energy measurements were also significantly different between AO cpTi and SA-treated cpTi surfaces (Tukey's, P<0.05). These data indicated that the change of physicochemical properties of an anodic titanium oxide film with HA crystals on an SA-treated cpTi surface may play a key role in the phenomenon of osteoconduction during the process of osseointegration. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Effect of anodic surface treatment on PAN-based carbon fiber and its relationship to the fracture toughness of the carbon fiber-reinforced polymer composites

    DEFF Research Database (Denmark)

    Sarraf, Hamid; Skarpova, Ludmila

    2008-01-01

    The effect of anodic surface treatment on the polyacrylonitrile (PAN)-based carbon fibers surface properties and the mechanical behavior of the resulting carbon fiber-polymer composites has been studied in terms of the contact angle measurements of fibers and the fracture toughness of composites...... in the fiber surface nature and the mechanical interfacial properties between the carbon fiber and epoxy resin matrix of the resulting composites, i.e., the fracture toughness. We suggest that good wetting plays an important role in improving the degree of adhesion at interfaces between fibers and matrices...

  6. Masking of aluminum surface against anodizing

    Science.gov (United States)

    Crawford, G. B.; Thompson, R. E.

    1969-01-01

    Masking material and a thickening agent preserve limited unanodized areas when aluminum surfaces are anodized with chromic acid. For protection of large areas it combines well with a certain self-adhesive plastic tape.

  7. A new, bright and hard aluminum surface produced by anodization

    Science.gov (United States)

    Hou, Fengyan; Hu, Bo; Tay, See Leng; Wang, Yuxin; Xiong, Chao; Gao, Wei

    2017-07-01

    Anodized aluminum (Al) and Al alloys have a wide range of applications. However, certain anodized finishings have relatively low hardness, dull appearance and/or poor corrosion resistance, which limited their applications. In this research, Al was first electropolished in a phosphoric acid-based solution, then anodized in a sulfuric acid-based solution under controlled processing parameters. The anodized specimen was then sealed by two-step sealing method. A systematic study including microstructure, surface morphology, hardness and corrosion resistance of these anodized films has been conducted. Results show that the hardness of this new anodized film was increased by a factor of 10 compared with the pure Al metal. Salt spray corrosion testing also demonstrated the greatly improved corrosion resistance. Unlike the traditional hard anodized Al which presents a dull-colored surface, this newly developed anodized Al alloy possesses a very bright and shiny surface with good hardness and corrosion resistance.

  8. Improvement of the current efficiency of an Al-Zn-In anode by heat-treatment

    International Nuclear Information System (INIS)

    Lin, J.C.; Shih, H.C.

    1987-01-01

    Aluminum anodes, each having one of several heat-treatments [namely as-cast (A), furnace-cooled (B), quenched (C), and quenched and aged (D-1)] were electrically coupled to structural steels to provide cathodic protection. The electro-chemical potential of each galvanic couple depended on the type of heat-treatment: anodes A, B, and C exhibited a potential of -1.10V, and anode D-1 was somewhat less negative at -0.95V. Empirical relationships between galvanic current density and area ratio (AR), based on 120h tests, have been established. Surface examination showed that anodes A, B, and C corrode uniformly, whereas anode D-1 dissolves locally. Results showed that the current efficiency of a sacrificial aluminum anode is dependent on its microstructure, which is, in turn, affected by its heat-treatment. Both anodes A and B possessed an equilibrium precipitate of In and the corresponding efficiencies did not vary with time. However, anode C, and especially anode D-1, suffered from aging, and their efficiencies varied with time. The microstructure of anode C contained thermal defects such as dislocation loops, while anode D-1 contained both dislocation loops and microsegregates. Results confirm that as-cast and furnace-cooled anodes have the best efficiencies (94-98%), while quenched and aged anodes have significantly lower efficiencies

  9. Anodic electrochemical treatment of amorphous alloys

    International Nuclear Information System (INIS)

    Isaev, N.I.; Yakovlev, V.B.; Osipov, Eh.K.; Isaev, A.V.; Trofimova, E.A.; Vasil'ev, V.Yu.

    1983-01-01

    The aim of the investigation is to reveal peculiarities of the process of anodic oxidation and properties of anode oxide films, formed on the surface of amorphous alloys. Amorphous alloys on the base of rectifying metals of Zr-Ni, Zr-Cu-Ni, Zr-Al-Ni, Zr-Cu-Sn, Zr-Al, Zr-Mo systems are studied. Electrolytes which do not dissolve or weakly dissolve oxide film, such as boric acid electrolyte (40-45 g/l H 3 BO 3 and 18 cm 3 /l of the 25% aqueous NH 4 OH solution) and 20% H 2 SO 4 solution, are used for oxidation. Results of investigations, carried out on amorphous alloys, contaning noticeable quantities of non-rectifying components - Cu, Ni, Sn, Fe, Mo etc - have shown that non-rectifying components harden a process of anodic oxidation and decrease the current efficiency. Amorphous alloys, containing only rectifying components are oxidated in anodic way, the regularities of film growth being similar to those obtained for crystalline materials

  10. Surface nanotopography of an anodized Ti–6Al–7Nb alloy enhances cell growth

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Her-Hsiung [Department of Dentistry, National Yang-Ming University, Taipei 112, Taiwan (China); Graduate Institute of Basic Medical Science, China Medical University, Taichung 404, Taiwan (China); Department of Biomedical Informatics, Asia University, Taichung 413, Taiwan (China); Department of Stomatology, Taipei Veterans General Hospital, Taipei 112, Taiwan (China); Wu, Chia-Ping [Institute of Oral Biology, National Yang-Ming University, Taipei 112, Taiwan (China); Sun, Ying-Sui [Department of Dentistry, National Yang-Ming University, Taipei 112, Taiwan (China); Yang, Wei-En [Institute of Oral Biology, National Yang-Ming University, Taipei 112, Taiwan (China); Lee, Tzu-Hsin, E-mail: biomaterials@hotmail.com [School of Dentistry, Chung Shan Medical University, Taichung 402, Taiwan (China); Oral Medicine Center, Chung Shan Medical University Hospital, Taichung 402, Taiwan (China)

    2014-12-05

    Highlights: • An electrochemical anodization was applied to α/β-type Ti–6Al–7Nb alloy surface. • Anodized surface had a nontoxic nanoporous topography. • Anodized surface increased proteins adsorption due to nanotopography. • Anodized surface enhanced cell growth due to nanotopography. • Electrochemical anodization has potential as implant surface treatment. - Abstract: The α/β-type Ti–6Al–7Nb alloy is a potential replacement for α/β-type Ti–6Al–4V alloy, which is widely used in biomedical implant applications. The biological response to implant material is dependent on the surface characteristics of the material. In the present study, a simple and fast process was developed to perform an electrochemical anodization treatment on Ti–6Al–7Nb alloy. The proposed process yielded a thin surface nanotopography, which enhanced cell growth on the Ti–6Al–7Nb alloy. The surface characteristics, including the morphology, wettability, and protein adsorption, were investigated, and the cytotoxicity was evaluated according to International Organization for Standardization 10993-5 specifications. Cell adhesion of human bone marrow mesenchymal stem cells on the test specimens was observed via fluorescence microscopy and scanning electron microscopy. The anodization process produced a surface nanotopography (pore size <100 nm) on anodized Ti–6Al–7Nb alloy, which enhanced the wettability, protein adsorption, cell adhesion, cell migration, and cell mineralization. The results showed that the surface nanotopography produced using the proposed electrochemical anodization process enhanced cell growth on anodized Ti–6Al–7Nb alloy for implant applications.

  11. Surface nanotopography of an anodized Ti–6Al–7Nb alloy enhances cell growth

    International Nuclear Information System (INIS)

    Huang, Her-Hsiung; Wu, Chia-Ping; Sun, Ying-Sui; Yang, Wei-En; Lee, Tzu-Hsin

    2014-01-01

    Highlights: • An electrochemical anodization was applied to α/β-type Ti–6Al–7Nb alloy surface. • Anodized surface had a nontoxic nanoporous topography. • Anodized surface increased proteins adsorption due to nanotopography. • Anodized surface enhanced cell growth due to nanotopography. • Electrochemical anodization has potential as implant surface treatment. - Abstract: The α/β-type Ti–6Al–7Nb alloy is a potential replacement for α/β-type Ti–6Al–4V alloy, which is widely used in biomedical implant applications. The biological response to implant material is dependent on the surface characteristics of the material. In the present study, a simple and fast process was developed to perform an electrochemical anodization treatment on Ti–6Al–7Nb alloy. The proposed process yielded a thin surface nanotopography, which enhanced cell growth on the Ti–6Al–7Nb alloy. The surface characteristics, including the morphology, wettability, and protein adsorption, were investigated, and the cytotoxicity was evaluated according to International Organization for Standardization 10993-5 specifications. Cell adhesion of human bone marrow mesenchymal stem cells on the test specimens was observed via fluorescence microscopy and scanning electron microscopy. The anodization process produced a surface nanotopography (pore size <100 nm) on anodized Ti–6Al–7Nb alloy, which enhanced the wettability, protein adsorption, cell adhesion, cell migration, and cell mineralization. The results showed that the surface nanotopography produced using the proposed electrochemical anodization process enhanced cell growth on anodized Ti–6Al–7Nb alloy for implant applications

  12. Effects of anodizing parameters and heat treatment on nanotopographical features, bioactivity, and cell culture response of additively manufactured porous titanium.

    Science.gov (United States)

    Amin Yavari, S; Chai, Y C; Böttger, A J; Wauthle, R; Schrooten, J; Weinans, H; Zadpoor, A A

    2015-06-01

    Anodizing could be used for bio-functionalization of the surfaces of titanium alloys. In this study, we use anodizing for creating nanotubes on the surface of porous titanium alloy bone substitutes manufactured using selective laser melting. Different sets of anodizing parameters (voltage: 10 or 20V anodizing time: 30min to 3h) are used for anodizing porous titanium structures that were later heat treated at 500°C. The nanotopographical features are examined using electron microscopy while the bioactivity of anodized surfaces is measured using immersion tests in the simulated body fluid (SBF). Moreover, the effects of anodizing and heat treatment on the performance of one representative anodized porous titanium structures are evaluated using in vitro cell culture assays using human periosteum-derived cells (hPDCs). It has been shown that while anodizing with different anodizing parameters results in very different nanotopographical features, i.e. nanotubes in the range of 20 to 55nm, anodized surfaces have limited apatite-forming ability regardless of the applied anodizing parameters. The results of in vitro cell culture show that both anodizing, and thus generation of regular nanotopographical feature, and heat treatment improve the cell culture response of porous titanium. In particular, cell proliferation measured using metabolic activity and DNA content was improved for anodized and heat treated as well as for anodized but not heat-treated specimens. Heat treatment additionally improved the cell attachment of porous titanium surfaces and upregulated expression of osteogenic markers. Anodized but not heat-treated specimens showed some limited signs of upregulated expression of osteogenic markers. In conclusion, while varying the anodizing parameters creates different nanotube structure, it does not improve apatite-forming ability of porous titanium. However, both anodizing and heat treatment at 500°C improve the cell culture response of porous titanium

  13. Effects of the nanotopographic surface structure of commercially pure titanium following anodization-hydrothermal treatment on gene expression and adhesion in gingival epithelial cells.

    Science.gov (United States)

    Takebe, J; Miyata, K; Miura, S; Ito, S

    2014-09-01

    The long-term stability and maintenance of endosseous implants with anodized-hydrothermally treated commercially pure titanium surfaces and a nanotopographic structure (SA-treated c.p.Ti) depend on the barrier function provided by the interface between the transmucosal portion of the implant surface and the peri-implant epithelium. This study investigated the effects of extracellular and intracellular gene expression in adherent gingival epithelial cells cultured for 1-7 days on SA-treated c.p.Ti implant surfaces compared to anodic oxide (AO) c.p.Ti and c.p.Ti disks. Scanning electron microscopy (SEM) showed filopodium-like extensions bound closely to the nanotopographic structure of SA-treated c.p.Ti at day 7 of culture. Gene expressions of focal adhesion kinase, integrin-α6β4, and laminin-5 (α3, β3, γ2) were significantly higher on SA-treated c.p.Ti than on c.p.Ti or AO c.p.Ti after 7 days (Pcells adhere to SA-treated c.p.Ti as the transmucosal portion of an implant, and that this interaction markedly improves expression of focal adhesion molecules and enhances the epithelial cell phenotype. The cellular gene expression responses driving extracellular and intracellular molecular interactions thus play an important role in maintenance at the interface between SA-treated c.p.Ti implant surfaces and the gingival epithelial cells. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Effects of anodizing parameters and heat treatment on nanotopographical features, bioactivity, and cell culture response of additively manufactured porous titanium

    Energy Technology Data Exchange (ETDEWEB)

    Amin Yavari, S., E-mail: s.aminyavari@tudelft.nl [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands); Chai, Y.C. [Prometheus, Division of Skeletal Tissue Engineering, Bus 813, O& N1, Herestraat 49, KU Leuven, 3000 Leuven (Belgium); Tissue Engineering Laboratory, Skeletal Biology and Engineering Research Center, Bus 813, O& N1, Herestraat 49, KU Leuven, 3000 Leuven (Belgium); Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Böttger, A.J. [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands); Wauthle, R. [KU Leuven, Department of Mechanical Engineering, Section Production Engineering, Machine Design and Automation (PMA), Celestijnenlaan 300B, 3001 Leuven (Belgium); 3D Systems — LayerWise NV, Grauwmeer 14, 3001 Leuven (Belgium); Schrooten, J. [Department of Metallurgy and Materials Engineering, KU Leuven, Kasteelpark Arenberg 44 — PB2450, B-3001 Heverlee (Belgium); Weinans, H. [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands); Department of Orthopedics and Dept. Rheumatology, UMC Utrecht, Heidelberglaan100, 3584CX Utrecht (Netherlands); Zadpoor, A.A. [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands)

    2015-06-01

    Anodizing could be used for bio-functionalization of the surfaces of titanium alloys. In this study, we use anodizing for creating nanotubes on the surface of porous titanium alloy bone substitutes manufactured using selective laser melting. Different sets of anodizing parameters (voltage: 10 or 20 V anodizing time: 30 min to 3 h) are used for anodizing porous titanium structures that were later heat treated at 500 °C. The nanotopographical features are examined using electron microscopy while the bioactivity of anodized surfaces is measured using immersion tests in the simulated body fluid (SBF). Moreover, the effects of anodizing and heat treatment on the performance of one representative anodized porous titanium structures are evaluated using in vitro cell culture assays using human periosteum-derived cells (hPDCs). It has been shown that while anodizing with different anodizing parameters results in very different nanotopographical features, i.e. nanotubes in the range of 20 to 55 nm, anodized surfaces have limited apatite-forming ability regardless of the applied anodizing parameters. The results of in vitro cell culture show that both anodizing, and thus generation of regular nanotopographical feature, and heat treatment improve the cell culture response of porous titanium. In particular, cell proliferation measured using metabolic activity and DNA content was improved for anodized and heat treated as well as for anodized but not heat-treated specimens. Heat treatment additionally improved the cell attachment of porous titanium surfaces and upregulated expression of osteogenic markers. Anodized but not heat-treated specimens showed some limited signs of upregulated expression of osteogenic markers. In conclusion, while varying the anodizing parameters creates different nanotube structure, it does not improve apatite-forming ability of porous titanium. However, both anodizing and heat treatment at 500 °C improve the cell culture response of porous titanium

  15. Electrochemical and morphological analyses on the titanium surface modified by shot blasting and anodic oxidation processes

    Energy Technology Data Exchange (ETDEWEB)

    Szesz, Eduardo M., E-mail: eszesz@neoortho.com.br [Neoortho Research Institute, Rua Ângelo Domingos Durigan, 607-Cascatinha, CEP 82025-100 Curitiba, PR (Brazil); Pereira, Bruno L., E-mail: brnl7@hotmail.com [Physics Department, Universidade Federal do Paraná, 81531-980 Curitiba, PR (Brazil); Kuromoto, Neide K., E-mail: kuromoto@fisica.ufpr.br [Physics Department, Universidade Federal do Paraná, 81531-980 Curitiba, PR (Brazil); Marino, Claudia E.B., E-mail: claudiamarino@yahoo.com [Mechanical Engineering Department, Universidade Federal do Paraná, 81531-980 Curitiba, PR (Brazil); Souza, Gelson B. de, E-mail: gelsonbs@uepg.br [Physics Department, Universidade Estadual de Ponta Grossa, 84051-510 Ponta Grossa, PR (Brazil); Soares, Paulo, E-mail: pa.soares@pucpr.br [Mechanical Engineering Department, Pontifícia Universidade Católica do Paraná, 80215-901 Curitiba, PR (Brazil)

    2013-01-01

    In recent years, many surface modification processes have been developed in order to induce the osseointegration on titanium surface and thus to improve the implants' biocompatibility. In this work, Ti surface has been modified by shot blasting followed by anodic oxidation process in order to associate the good surface characteristics of both processes to obtain a rough and porous surface able to promote the titanium surface bioactivity. Commercially pure titanium (grade 2) plates were used on the surface treatments that were as follows: Shot blasting (SB) performed using alumina (Al{sub 2}O{sub 3}) particles, and anodic oxidation (AO) using NaOH electrolyte. The morphology, structural changes and the open-circuit potentials (OCP) of the surfaces were analyzed. It can be observed that an increase on the roughness of the blasted surface and a rough and porous surface happens after the AO process. The anodic film produced is thin and followed the blasted surface topography. It can be observed that there are small pores with regular shape covering the entire surface. X-ray diffraction results showed the presence of the anatase and rutile phases on the blasted and anodized surface after heat treatment at 600 °C/1 h. Concerning electrochemical measurements, when the different samples were submitted to open-circuit conditions in a physiological electrolyte, the protective effect increases with the oxidation process due to the oxide layer. When the surface was blasted, the OCP was more negative when compared with the Ti surface without surface treatments. - Highlights: ► A combination of shot blasting and anodic oxidation surface treatments is proposed. ► Both processes produced an increase in roughness compared to the polished surface. ► The combination of processes produced a rough and porous surface. ► Open circuit results show that the protective effect increases with oxidation process. ► The combination of processes presents the better results in this

  16. Removal of organic contaminants from secondary effluent by anodic oxidation with a boron-doped diamond anode as tertiary treatment

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Segura, Sergi, E-mail: sergigarcia@ub.edu [Advanced Water Management Centre, The University of Queensland, Level 4, Gehrmann Bld. (60), St Lucia, QLD 072 (Australia); Laboratori d’Electroquímica dels Materials i del Medi Ambient, Departament de Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona (Spain); Keller, Jürg [Advanced Water Management Centre, The University of Queensland, Level 4, Gehrmann Bld. (60), St Lucia, QLD 072 (Australia); Brillas, Enric [Laboratori d’Electroquímica dels Materials i del Medi Ambient, Departament de Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona (Spain); Radjenovic, Jelena, E-mail: j.radjenovic@awmc.uq.edu.au [Advanced Water Management Centre, The University of Queensland, Level 4, Gehrmann Bld. (60), St Lucia, QLD 072 (Australia)

    2015-02-11

    Graphical abstract: - Highlights: • Mineralization of secondary effluent by anodic oxidation with BDD anode. • Complete removal of 29 pharmaceuticals and pesticides at trace level concentrations. • Organochlorine and organobromine byproducts were formed at low μM concentrations. • Chlorine species evolution assessed to evaluate the anodic oxidation applicability. - Abstract: Electrochemical advanced oxidation processes (EAOPs) have been widely investigated as promising technologies to remove trace organic contaminants from water, but have rarely been used for the treatment of real waste streams. Anodic oxidation with a boron-doped diamond (BDD) anode was applied for the treatment of secondary effluent from a municipal sewage treatment plant containing 29 target pharmaceuticals and pesticides. The effectiveness of the treatment was assessed from the contaminants decay, dissolved organic carbon and chemical oxygen demand removal. The effect of applied current and pH was evaluated. Almost complete mineralization of effluent organic matter and trace contaminants can be obtained by this EAOP primarily due to the action of hydroxyl radicals formed at the BDD surface. The oxidation of Cl{sup −} ions present in the wastewater at the BDD anode gave rise to active chlorine species (Cl{sub 2}/HClO/ClO{sup −}), which are competitive oxidizing agents yielding chloramines and organohalogen byproducts, quantified as adsorbable organic halogen. However, further anodic oxidation of HClO/ClO{sup −} species led to the production of ClO{sub 3}{sup −} and ClO{sub 4}{sup −} ions. The formation of these species hampers the application as a single-stage tertiary treatment, but posterior cathodic reduction of chlorate and perchlorate species may reduce the risks associated to their presence in the environment.

  17. Application of Anodization Process for Cast Aluminium Surface Properties Enhancement

    Directory of Open Access Journals (Sweden)

    Włodarczyk-Fligier A.

    2016-09-01

    Full Text Available An huge interest is observed in last years in metal matrix composite, mostly light metal based, which have found their applications in many industry branches, among others in the aircraft industry, automotive-, and armaments ones, as well as in electrical engineering and electronics, where one of the most important issue is related to the corrosion resistance, especially on the surface layer of the used aluminium alloys. This elaboration presents the influence of ceramic phase on the corrosion resistance, quality of the surface layer its thickness and structure of an anodic layer formed on aluminium alloys. As test materials it was applied the aluminium alloys Al-Si-Cu and Al-Cu-Mg, for which heat treatment processes and corrosion tests were carried out. It was presented herein grindability test results and metallographic examination, as well. Hardness of the treated alloys with those ones subjected to corrosion process were compared.

  18. Surface Modification of Titanium Using Anodization to Enhance Antimicrobial Properties and Osseointegration

    Science.gov (United States)

    Jain, Sakshi

    Titanium and its alloys are frequently used in dental and orthopedic implants because they have good mechanical strength, chemical stability and biocompatibility. These properties can be further improved by surface treatments such as anodization that are able to grow thicker and produce crystalline oxide layers with controlled morphological and physico-chemical properties. Both anatase (A) and rutile (R) crystalline phases of titanium oxide have been shown to promote bioactivity and antimicrobial effects. In a previous study in our laboratories, four electrolyte mixtures were optimized to produce anodized layers on commercially pure titanium consisting of specific anatase and rutile oxide ratios at an endpoint forming voltage of 180 V. In the present study, changes that occurred in the anodized layers with increasing forming voltage including crystallinity, thickness, surface morphology, surface roughness, surface chemistry, fractal dimension, shear strength, and corrosion resistance were determined for each of these electrolytes. The results showed the crystallinity, thickness, surface pore sizes, and surface roughness increased with increasing forming voltage. Incorporation of phosphorus into the anodized layers was shown in phosphoric acid containing electrolytes at higher forming voltages. Decreases in corrosion resistance were also shown at higher forming voltages in each electrolyte due to increased pore interconnectivity within the anodized layers. In addition, the apatite inducing ability of anodized layers in SBF was examined for selected forming voltages in each electrolyte. Anodization in phosphoric acid containing electrolytes was shown to be more favorable for apatite formation. The streptococcal and MRSA bacterial attachment before and after UV treatments was determined for selected forming voltages in each electrolyte. Additionally, the killing efficacy after 10-minute pre-irradiation with UVA or UVC treatments was determined. UVA treatments showed

  19. Effect of heat treatment on anodic activation of aluminium by trace element indium

    Energy Technology Data Exchange (ETDEWEB)

    Graver, Brit [Department of Materials Science and Engineering, Norwegian University of Science and Technology, N-7491 Trondheim (Norway); Helvoort, Antonius T.J. van [Department of Physics, Norwegian University of Science and Technology, N-7491 Trondheim (Norway); Nisancioglu, Kemal, E-mail: kemal.nisancioglu@material.ntnu.n [Department of Materials Science and Engineering, Norwegian University of Science and Technology, N-7491 Trondheim (Norway)

    2010-11-15

    Research highlights: {yields} Indium segregation activates AlIn alloy surface anodically in chloride solution. {yields} Enrichment of In on Al surface can occur thermally by heat treatment at 300 {sup o}C. {yields} Increasing temperature homogenises indium in aluminium reducing anodic activation. {yields} Indium can activate AlIn surface by segregating through dealloying of aluminium. {yields} Anodic activation is caused by AlIn amalgam formation at aluminium surface. - Abstract: The presence of trace elements in Group IIIA-VA is known to activate aluminium anodically in chloride environment. The purpose of this paper is to investigate the surface segregation of trace element In by heat treatment and resulting surface activation. Model binary AlIn alloys, containing 20 and 1000 ppm by weight of In, were characterized after heat treatment at various temperatures by use of glow discharge optical emission spectroscopy, electron microscopy and electrochemical polarization. Heat treatment for 1 h at 300 {sup o}C gave significant segregation of discrete In particles (thermal segregation), which activated the surface. Indium in solid solution with aluminium, obtained by 1 h heat treatment at 600 {sup o}C, also activated by surface segregation of In on alloy containing 1000 ppm In, resulting from the selective dissolution of the aluminium component during anodic oxidation (anodic segregation). The effect of anodic segregation was reduced by decreasing indium concentration in solid solution; it had negligible effect at the 20 ppm level. The segregated particles were thought to form a liquid phase alloy with aluminium during anodic polarization, which in turn, together with the chloride in the solution destabilized the oxide.

  20. Investigation of anodic oxide coatings on zirconium after heat treatment

    International Nuclear Information System (INIS)

    Sowa, Maciej; Dercz, Grzegorz; Suchanek, Katarzyna; Simka, Wojciech

    2015-01-01

    Highlights: • Oxide layers prepared via PEO of zirconium were subjected to heat treatment. • Surface characteristics were determined for the obtained oxide coatings. • Heat treatment led to the partial destruction of the anodic oxide layer. • Pitting corrosion resistance of zirconium was improved after the modification. - Abstract: Herein, results of heat treatment of zirconium anodised under plasma electrolytic oxidation (PEO) conditions at 500–800 °C are presented. The obtained oxide films were investigated by means of SEM, XRD and Raman spectroscopy. The corrosion resistance of the zirconium specimens was evaluated in Ringer's solution. A bilayer oxide coatings generated in the course of PEO of zirconium were not observed after the heat treatment. The resulting oxide layers contained a new sublayer located at the metal/oxide interface is suggested to originate from the thermal oxidation of zirconium. The corrosion resistance of the anodised metal was improved after the heat treatment

  1. The effect of different aluminum alloy surface compositions on barrier anodic film formation

    International Nuclear Information System (INIS)

    Panitz, J.K.G.; Sharp, D.J.

    1984-01-01

    The authors have grown barrier anodic coatings on samples of aluminum alloy with different elemental surface compositions. In one series of experiments, they characterized the surface composition present on 6061 aluminum alloy samples after different chemical treatments including a detergent-water and methyl-ethyl ketone solvent clean, a 50% nitric acid-water etch, and a concentrated nitric acid-ammonium bifluoride etch. They anodized samples which were prepared similarly to those analyzed to evaluate the practical effects of the three different surface compositions. The anodization voltage rise time to 950V at constant current was used as a figure of merit. The solvent cleaned and the 50% nitric acid etched samples required, respectively, 113% and 41% more time to reach 950V than the concentrated nitric acidammonium bifloride etched samples. In a second series of experiments, they alternately anodized groups of either 6061 or 1100 (commercially pure) aluminum alloy, observed rise times to 950V, and measured chloride ion concentrations in the electrolyte. Longer rise times and higher chloride ion concentrations were observed for the 1100 samples. It was observed that the chloride ion concentration fell from initially high levels when 6061 samples were anodized. The results of both series of experiments augment the results of other investigators, who report that the surface species initially present on aluminum have a significant effect on anodic film formation

  2. [Corrosion resistant properties of different anodized microtopographies on titanium surfaces].

    Science.gov (United States)

    Fangjun, Huo; Li, Xie; Xingye, Tong; Yueting, Wang; Weihua, Guo; Weidong, Tian

    2015-12-01

    To investigate the corrosion resistant properties of titanium samples prepared by anodic oxidation with different surface morphologies. Pure titanium substrates were treated by anodic oxidation to obtain porous titanium films in micron, submicron, and micron-submicron scales. The surface morphologies, coating cross-sectional morphologies, crystalline structures, and surface roughness of these samples were characterized. Electrochemical technique was used to measure the corrosion potential (Ecorr), current density of corrosion (Icorr), and polarization resistance (Rp) of these samples in a simulated body fluid. Pure titanium could be modified to exhibit different surface morphologies by the anodic oxidation technique. The Tafel curve results showed that the technique can improve the corrosion resistance of pure titanium. Furthermore, the corrosion resistance varied with different surface morphologies. The submicron porous surface sample demonstrated the best corrosion resistance, with maximal Ecorr and Rp and minimal Icorr. Anodic oxidation technology can improve the corrosion resistance of pure titanium in a simulated body fluid. The submicron porous surface sample exhibited the best corrosion resistance because of its small surface area and thick barrier layer.

  3. Surface of Alumina Films after Prolonged Breakdowns in Galvanostatic Anodization

    Directory of Open Access Journals (Sweden)

    Christian Girginov

    2011-01-01

    Full Text Available Breakdown phenomena are investigated at continuous isothermal (20∘C and galvanostatic (0.2–5 mA cm−2 anodizing of aluminum in ammonium salicylate in dimethylformamide (1 M AS/DMF electrolyte. From the kinetic (-curves, the breakdown voltage ( values are estimated, as well as the frequency and amplitude of oscillations of formation voltage ( at different current densities. The surface of the aluminum specimens was studied using atomic force microscopy (AFM. Data on topography and surface roughness parameters of the electrode after electric breakdowns are obtained as a function of anodization time. The electrode surface of anodic films, formed with different current densities until the same charge density has passed (2.5 C cm−2, was assessed. Results are discussed on the basis of perceptions of avalanche mechanism of the breakdown phenomena, due to the injection of electrons and their multiplication in the volume of the film.

  4. Variation on wettability of anodic zirconium oxide nanotube surface

    International Nuclear Information System (INIS)

    Wang, Lu-Ning; Shen, Chen; Shinbine, Alyssa; Luo, Jing-Li

    2013-01-01

    The present study reports the effect of fabrication conditions and environmental conditions, such as anodization voltage and aging period, on the wetting of zirconium dioxide nanotube (ZrNT) surfaces. Comparing with intact zirconium foil, which was inherently less hydrophilic, possessing an approximate contact angle of 60–70°, the as-formed ZrNT surfaces were much hydrophilic with an approximate contact angle of 18°. However, the hydrophilicity of the surfaces exhibited a decrease when the nanotubular opening diameters decreased while maintaining the nanotubular layer thickness. This phenomenon was attributed to the balance of capillary force and force generated by compressed air in the ZrNTs. The annealing treatment further increased the hydrophilic property of the ZrNTs. In addition, it was found that the wettability of ZrNTs, when aged in air over a period of 105 days, demonstrated a decrease in hydrophilic characteristics and exhibited, to some extent, an increase in hydrophobic characteristics. It was believed that the surface wettability was able to be changed due to the decreasing content of hydroxyl groups in ambient atmosphere. This work can provide guidelines for improving the structural and environmental conditions responsible for changing surface wettability of ZrNT surfaces for biomedical application. - Highlights: ► Wettability of zirconium oxide nanotubes (ZrNTs) was observed and characterized. ► Increasing of nanotubular diameter decreased the hydrophilicity of ZrNTs. ► Annealing processes enhanced the hydrophilicity of ZrNTs. ► Long term aging resulted in the hydrophobicity of ZrNTs

  5. Water and oil wettability of anodized 6016 aluminum alloy surface

    Science.gov (United States)

    Rodrigues, S. P.; Alves, C. F. Almeida; Cavaleiro, A.; Carvalho, S.

    2017-11-01

    This paper reports on the control of wettability behaviour of a 6000 series aluminum (Al) alloy surface (Al6016-T4), which is widely used in the automotive and aerospace industries. In order to induce the surface micro-nanostructuring of the surface, a combination of prior mechanical polishing steps followed by anodization process with different conditions was used. The surface polishing with sandpaper grit size 1000 promoted aligned grooves on the surface leading to static water contact angle (WCA) of 91° and oil (α-bromonaphthalene) contact angle (OCA) of 32°, indicating a slightly hydrophobic and oleophilic character. H2SO4 and H3PO4 acid electrolytes were used to grow aluminum oxide layers (Al2O3) by anodization, working at 15 V/18° C and 100 V/0 °C, respectively, in one or two-steps configuration. Overall, the anodization results showed that the structured Al surfaces were hydrophilic and oleophilic-like with both WCA and OCA below 90°. The one-step configuration led to a dimple-shaped Al alloy surface with small diameter of around 31 nm, in case of H2SO4, and with larger diameters of around 223 nm in case of H3PO4. The larger dimples achieved with H3PO4 electrolyte allowed to reach a slight hydrophobic surface. The thicker porous Al oxide layers, produced by anodization in two-step configuration, revealed that the liquids can penetrate easily inside the non-ordered porous structures and, thus, the surface wettability tended to superhydrophilic and superoleophilic character (CA OCA. This inversion in favour of the hydrophilic-oleophobic surface behaviour is of great interest either for lubrication of mechanical components or in water-oil separation process.

  6. Iron migration from the anode surface in alumina electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Zhuravleva, Elena N.; Drozdova, Tatiana N.; Ponomareva, Svetlana V. [Siberian Federal University, Krasnoyarsk, 660041 (Russian Federation); Kirik, Sergei D., E-mail: kiriksd@yandex.ru [Siberian Federal University, Krasnoyarsk, 660041 (Russian Federation); Institute of Chemistry and Chemical Technology SB RAS, Krasnoyarsk, 660036 (Russian Federation)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Corrosion destruction of two-component iron-based alloys in high-temperature aluminum electrolysis in the cryolite alumina melt has been studied. Black-Right-Pointing-Pointer It was found that at the first stage oxidative polarization of iron atoms on the anode surface into Fe{sup 2+} takes place. Black-Right-Pointing-Pointer Fe{sup 2+} interacts with cryolite melt producing FeF{sub 2}. Black-Right-Pointing-Pointer FeF{sub 2} gives oxides FeAl{sub 2}O{sub 4}, Fe{sub 3}O{sub 4}, Fe{sub 2}O{sub 3}. Black-Right-Pointing-Pointer The participation of oxygen in the corrosion has not been observed. - Abstract: Corrosion destruction of two-component iron-based alloys used as an anode in high-temperature alumina electrolysis in the melt of NaF/KF/AlF{sub 3} electrolyte has been considered. Ni, Si, Cu, Cr, Mn, Al, Ti in the amount of up to 10% have been tested as the dopants to an anode alloys. The composition of the corrosion products has been studied using X-ray diffraction, scanning electron microscopy and electron microprobe analysis. It has been established that the anode corrosion is induced by a surface electrochemical polarization and iron atom oxidation. Iron ions come into an exchange interaction with the fluoride components of the melted electrolyte, producing FeF{sub 2}. The last interacts with oxyfluoride species transforming into the oxide forms: FeAl{sub 2}O{sub 4}, Fe{sub 3}O{sub 4}, Fe{sub 2}O{sub 3}. Due to the low solubility, the iron oxides are accumulated in the near-electrode sheath. The only small part of iron from anode migrates to cathode that makes an production of high purity aluminum of a real task. The alloy dopants are also subjected to corrosion in accordance with electromotive series resulting corrosion tunnels on the anode surface. The oxides are final compounds which collect in the same area. The corrosion products form an anode shell which is electronic conductor at electrolysis temperature. The

  7. Phenol Contaminated Water Treatment on Several Modified Dimensionally Stable Anodes.

    Science.gov (United States)

    Jayathilaka, Pavithra Bhakthi; Hapuhinna, Kushani Umanga Kumari; Bandara, Athula; Nanayakkara, Nadeeshani; Subasinghe, Nalaka Deepal

    2017-08-01

      Phenolic compounds are some of the most common hazardous organics in wastewater. Removal of these pollutants is important. Physiochemical method such as electrochemical oxidation on dimensionally stable anodes is more convenient in removing such organic pollutants. Therefore, this study focuses on development of three different anodes for phenol contaminated water treatment. The performances of steel/IrO2, steel/IrO2-Sb2O3, and Ti/IrO2-Sb2O3 anodes were tested and compared. Nearly 50, 76, and 84% of chemical oxygen demand removal efficiencies were observed for steel/IrO2, steel/IrO2-Sb2O3, and Ti/IrO2-Sb2O3 anodes, respectively. The formation of intermediates was monitored for three anodes and the Ti/IrO2-Sb2O3 anode showed the most promising results. Findings suggest that the developed anode materials can enhance phenol oxidation efficiency and that mixed metal oxide layer has major influence on the anode. Among the selected metal oxide mixtures IrO2-Sb2O3 was the most suitable under given experimental conditions.

  8. Improvements in the corrosion resistance and biocompatibility of biomedical Ti–6Al–7Nb alloy using an electrochemical anodization treatment

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Her-Hsiung [Department of Dentistry, National Yang-Ming University, Taipei 112, Taiwan (China); Department of Dentistry, Taipei City Hospital, Taipei 115, Taiwan (China); Department of Stomatology, Taipei Veterans General Hospital, Taipei 112, Taiwan (China); Wu, Chia-Ping; Sun, Ying-Sui [Department of Oral Biology, National Yang-Ming University, Taipei 112, Taiwan (China); Lee, Tzu-Hsin, E-mail: biomaterials@hotmail.com [School of Dentistry, Chung Shan Medical University, Taichung 402, Taiwan (China); Department of Dentistry, Chung Shan Medical University Hospital, Taichung 402, Taiwan (China)

    2013-01-01

    The biocompatibility of an implant material is determined by its surface characteristics. This study investigated the application of an electrochemical anodization surface treatment to improve both the corrosion resistance and biocompatibility of Ti–6Al–7Nb alloy for implant applications. The electrochemical anodization treatment produced an Al-free oxide layer with nanoscale porosity on the Ti–6Al–7Nb alloy surface. The surface topography and microstructure of Ti–6Al–7Nb alloy were analyzed. The corrosion resistance was investigated using potentiodynamic polarization curve measurements in simulated blood plasma (SBP). The adhesion and proliferation of human bone marrow mesenchymal stem cells to test specimens were evaluated using various biological analysis techniques. The results showed that the presence of a nanoporous oxide layer on the anodized Ti–6Al–7Nb alloy increased the corrosion resistance (i.e., increased the corrosion potential and decreased both the corrosion rate and the passive current) in SBP compared with the untreated Ti–6Al–7Nb alloy. Changes in the nanotopography also improved the cell adhesion and proliferation on the anodized Ti–6Al–7Nb alloy. We conclude that a fast and simple electrochemical anodization surface treatment improves the corrosion resistance and biocompatibility of Ti–6Al–7Nb alloy for biomedical implant applications. - Highlights: ► Simple/fast electrochemical anodization was applied to biomedical Ti–6Al–7Nb surface. ► Anodized surface had nano-porous topography and contained Al-free oxide layer. ► Anodized surface raised corrosion resistance in three simulated biological solutions. ► Anodized surface enhanced cell adhesion and cell proliferation. ► Electrochemical anodization has potential as biomedical implant surface treatment.

  9. Improvements in the corrosion resistance and biocompatibility of biomedical Ti–6Al–7Nb alloy using an electrochemical anodization treatment

    International Nuclear Information System (INIS)

    Huang, Her-Hsiung; Wu, Chia-Ping; Sun, Ying-Sui; Lee, Tzu-Hsin

    2013-01-01

    The biocompatibility of an implant material is determined by its surface characteristics. This study investigated the application of an electrochemical anodization surface treatment to improve both the corrosion resistance and biocompatibility of Ti–6Al–7Nb alloy for implant applications. The electrochemical anodization treatment produced an Al-free oxide layer with nanoscale porosity on the Ti–6Al–7Nb alloy surface. The surface topography and microstructure of Ti–6Al–7Nb alloy were analyzed. The corrosion resistance was investigated using potentiodynamic polarization curve measurements in simulated blood plasma (SBP). The adhesion and proliferation of human bone marrow mesenchymal stem cells to test specimens were evaluated using various biological analysis techniques. The results showed that the presence of a nanoporous oxide layer on the anodized Ti–6Al–7Nb alloy increased the corrosion resistance (i.e., increased the corrosion potential and decreased both the corrosion rate and the passive current) in SBP compared with the untreated Ti–6Al–7Nb alloy. Changes in the nanotopography also improved the cell adhesion and proliferation on the anodized Ti–6Al–7Nb alloy. We conclude that a fast and simple electrochemical anodization surface treatment improves the corrosion resistance and biocompatibility of Ti–6Al–7Nb alloy for biomedical implant applications. - Highlights: ► Simple/fast electrochemical anodization was applied to biomedical Ti–6Al–7Nb surface. ► Anodized surface had nano-porous topography and contained Al-free oxide layer. ► Anodized surface raised corrosion resistance in three simulated biological solutions. ► Anodized surface enhanced cell adhesion and cell proliferation. ► Electrochemical anodization has potential as biomedical implant surface treatment

  10. Hierarchically ordered self-lubricating superhydrophobic anodized aluminum surfaces with enhanced corrosion resistance.

    Science.gov (United States)

    Vengatesh, Panneerselvam; Kulandainathan, Manickam Anbu

    2015-01-28

    Herein, we report a facile method for the fabrication of self-lubricating superhydrophobic hierarchical anodic aluminum oxide (AAO) surfaces with improved corrosion protection, which is greatly anticipated to have a high impact in catalysis, aerospace, and the shipping industries. This method involves chemical grafting of as-formed AAO using low surface free energy molecules like long chain saturated fatty acids, perfluorinated fatty acid (perfluorooctadecanoic acid, PFODA), and perfluorosulfonicacid-polytetrafluoroethylene copolymer. The pre and post treatment processes in the anodization of aluminum (Al) play a vital role in the grafting of fatty acids. Wettability and surface free energy were analyzed using a contact angle meter and achieved 161.5° for PFODA grafted anodized aluminum (PFODA-Al). This study was also aimed at evaluating the surface for corrosion resistance by Tafel polarization and self-lubricating properties by tribological studies using a pin-on-disc tribometer. The collective results showed that chemically grafted AAO nanostructures exhibit high corrosion resistance toward seawater and low frictional coefficient due to low surface energy and self-lubricating property of fatty acids covalently linked to anodized Al surfaces.

  11. Use of Both Anode and Cathode Reactions in Wastewater Treatment

    Science.gov (United States)

    Brillas, Enric; Sirés, Ignasi; Cabot, Pere LluíS.

    Here, we describe the fundamentals, laboratory experiments, and environmental applications of indirect electrooxidation methods based on H2O2 electrogeneration such as electro-Fenton, photoelectro-Fenton and peroxicoagulation for the treatment of acidic wastewaters containing toxic and recalcitrant organics. These methods are electrochemical advanced oxidation processes that can be used in divided and undivided electrolytic cells in which pollutants are oxidized by hydroxyl radical (•OH) produced from anode and/or cathode reactions. H2O2 is generated from the two-electron reduction of O2 at reticulated vitreous carbon, graphite, carbon-felt, and O2-diffusion cathodes. The most usual method is electro-Fenton where Fe2 + added to the wastewater reacts with electrogenerated H2O2 to yield •OH and Fe3 + from Fenton's reaction. An advantage of this technique is that Fe2 + is continuously regenerated from cathodic reduction of Fe3 +. The characteristics of different electro-Fenton systems where pollutants are simultaneously destroyed by •OH formed in the medium from Fenton's reaction and at the anode surface from water oxidation are explained. The effect of the anode [Pt or boron-doped diamond (BDD)] and cathode (carbon-felt or O2-diffusion) on the degradation rate of persistent industrial by-products, herbicides, pharmaceuticals, dyes, etc. is examined. Initial pollutants react much more rapidly with •OH formed in the medium and their degradation sequences are discussed from aromatic intermediates and finally short aliphatic acids are detected. The synergetic positive catalytic effect of Cu2 + on the electro-Fenton process is evidenced. The photoelectro-Fenton method involves the irradiation of the wastewater with UVA light that rapidly photodecomposes complexes of Fe3 + with final carboxylic acids enhancing total decontamination. The peroxicoagulation method uses a sacrificial Fe anode that is continuously oxidized to Fe2 + and organics are either mineralized

  12. Nanotubular surface modification of metallic implants via electrochemical anodization technique.

    Science.gov (United States)

    Wang, Lu-Ning; Jin, Ming; Zheng, Yudong; Guan, Yueping; Lu, Xin; Luo, Jing-Li

    2014-01-01

    Due to increased awareness and interest in the biomedical implant field as a result of an aging population, research in the field of implantable devices has grown rapidly in the last few decades. Among the biomedical implants, metallic implant materials have been widely used to replace disordered bony tissues in orthopedic and orthodontic surgeries. The clinical success of implants is closely related to their early osseointegration (ie, the direct structural and functional connection between living bone and the surface of a load-bearing artificial implant), which relies heavily on the surface condition of the implant. Electrochemical techniques for modifying biomedical implants are relatively simple, cost-effective, and appropriate for implants with complex shapes. Recently, metal oxide nanotubular arrays via electrochemical anodization have become an attractive technique to build up on metallic implants to enhance the biocompatibility and bioactivity. This article will thoroughly review the relevance of electrochemical anodization techniques for the modification of metallic implant surfaces in nanoscale, and cover the electrochemical anodization techniques used in the development of the types of nanotubular/nanoporous modification achievable via electrochemical approaches, which hold tremendous potential for bio-implant applications. In vitro and in vivo studies using metallic oxide nanotubes are also presented, revealing the potential of nanotubes in biomedical applications. Finally, an outlook of future growth of research in metallic oxide nanotubular arrays is provided. This article will therefore provide researchers with an in-depth understanding of electrochemical anodization modification and provide guidance regarding the design and tuning of new materials to achieve a desired performance and reliable biocompatibility.

  13. Influence of Alkali Treatment on Anodized Titanium Alloys in Wollastonite Suspension

    Directory of Open Access Journals (Sweden)

    Alicja Kazek-Kęsik

    2017-08-01

    Full Text Available The surface modification of titanium alloys is an effective method to improve their biocompatibility and tailor the material to the desired profile of implant functionality. In this work, technologically-advanced titanium alloys—Ti-15Mo, Ti-13Nb-13Zr and Ti-6Al-7Nb—were anodized in suspensions, followed by treatment in alkali solutions, with wollastonite deposition from the powder phase suspended in solution. The anodized samples were immersed in NaOH or KOH solution with various concentrations with a different set of temperatures and exposure times. Based on their morphologies (observed by scanning electron microscope, the selected samples were investigated by Raman and X-ray photoelectron spectroscopy (XPS. Titaniate compounds were formed on the previously anodized titanium surfaces. The surface wettability significantly decreased, mainly on the modified Ti-15Mo alloy surface. Titanium alloy compounds had an influence on the results of the titanium alloys’ surface modification, which caused the surfaces to exhibit differential physical properties. In this paper, we present the influence of the anodization procedure on alkali treatment effects and the properties of obtained hybrid coatings.

  14. Osteoblast response on co-modified titanium surfaces via anodization and electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Bayram, Cem [Nanotechnology and Nanomedicine Division, Hacettepe University, Ankara, Beytepe, 06800 (Turkey); Chemistry Department, Aksaray University, Aksaray, 68100 (Turkey); Demirbilek, Murat; Yalçın, Eda [Nanotechnology and Nanomedicine Division, Hacettepe University, Ankara, Beytepe, 06800 (Turkey); Bozkurt, Murat; Doğan, Metin [Orthopaedics and Traumatology Division, Yıldırım Beyazıt University, School of Medicine, Cankaya, 06550 (Turkey); Denkbaş, Emir Baki, E-mail: denkbas@hacettepe.edu.tr [Chemistry Department, Hacettepe University, Ankara, Beytepe, 06800 (Turkey)

    2014-01-01

    Topography plays a key role in osseointegration and surface modifications at the subcellular level, increasing initial cell attachment in the early period. In the past decade, nanosized texture on metal like a nanotube layer and also more recently extracellular matrix like surface modifications – such as polymeric nanofibrils – have been proposed for a better osseointegration in the literature. Here, we investigate two types of nanoscaled modifications alone and together for the first time. We characterized different types of surface modifications morphologically and investigated how they affected osteoblast cells in vitro, in terms of cell adhesion, proliferation, alkaline phosphatase activity and calcium content. We anodized titanium samples with a thickness of 0.127 mm to obtain a nanotubular titania layer and the silk fibroin (SF), as a biocompatible polymeric material, was electrospun onto both anodized and unanodized samples to acquire 4 sample groups. We analyzed the resulting samples morphologically by scanning electron microscopy (SEM). Cell adhesion, proliferation, alkaline phosphatase (ALP) activity and calcium content were evaluated at 3, 7 and 14 days. We found that cell proliferation increased by 70% on the groups having two modifications respect to unmodified titanium and after 7 days, ALP activity and calcium content were 110% and 150%, respectively, higher on surfaces having both surface treatments than that of unmodified group. In conclusion, a nanotube layer and SF nanofibers on a titanium surface enhanced cell attachment and proliferation most. Comodification of titanium surfaces by anodization and SF electrospinning may be useful to enhance osseointegration but it requires in vivo confirmation.

  15. Microscopic observation of pattern attack by aggressive ions on finished surface of aluminium alloy sacrificial anode

    International Nuclear Information System (INIS)

    Zaifol Samsu; Muhammad Daud; Siti Radiah Mohd Kamarudin; Nur Ubaidah Saidin; Azali Muhammad; Mohd Shaari Ripin; Rusni Rejab; Mohd Shariff Sattar

    2010-01-01

    This paper presents the results of a microscopic observation on submerged finished surface of aluminium alloy sacrificial anode. Experimental tests were carried out on polished surface aluminium anode exposed to seawater containing aggressive ions in order to observe of pattern corrosion attack on corroding surface of anode. Results have shown, at least under the present testing condition, that surface of sacrificial anode were attack by an aggressive ion such as chloride along grain boundaries. In addition, results of microanalysis showed that the corrosion products on surface of aluminium alloy have Al, Zn and O element for all sample and within the pit was consists of Al, Zn, O and Cl element. (author)

  16. Synthesis and characterization of hybrid micro/nano-structured NiTi surfaces by a combination of etching and anodizing

    Science.gov (United States)

    Huan, Z.; Fratila-Apachitei, L. E.; Apachitei, I.; Duszczyk, J.

    2014-02-01

    The purpose of this study was to generate hybrid micro/nano-structures on biomedical nickel-titanium alloy (NiTi). To achieve this, NiTi surfaces were firstly electrochemically etched and then anodized in fluoride-containing electrolyte. With the etching process, the NiTi surface was micro-roughened through the formation of micropits uniformly distributed over the entire surface. Following the subsequent anodizing process, self-organized nanotube structures enriched in TiO2 could be superimposed on the etched surface under specific conditions. Furthermore, the anodizing treatment significantly reduced water contact angles and increased the surface free energy compared to the surfaces prior to anodizing. The results of this study show for the first time that it is possible to create hybrid micro/nano-structures on biomedical NiTi alloys by combining electrochemical etching and anodizing under controlled conditions. These novel structures are expected to significantly enhance the surface biofunctionality of the material when compared to conventional implant devices with either micro- or nano-structured surfaces.

  17. Synthesis and characterization of hybrid micro/nano-structured NiTi surfaces by a combination of etching and anodizing

    International Nuclear Information System (INIS)

    Huan, Z; Fratila-Apachitei, L E; Apachitei, I; Duszczyk, J

    2014-01-01

    The purpose of this study was to generate hybrid micro/nano-structures on biomedical nickel–titanium alloy (NiTi). To achieve this, NiTi surfaces were firstly electrochemically etched and then anodized in fluoride-containing electrolyte. With the etching process, the NiTi surface was micro-roughened through the formation of micropits uniformly distributed over the entire surface. Following the subsequent anodizing process, self-organized nanotube structures enriched in TiO 2 could be superimposed on the etched surface under specific conditions. Furthermore, the anodizing treatment significantly reduced water contact angles and increased the surface free energy compared to the surfaces prior to anodizing. The results of this study show for the first time that it is possible to create hybrid micro/nano-structures on biomedical NiTi alloys by combining electrochemical etching and anodizing under controlled conditions. These novel structures are expected to significantly enhance the surface biofunctionality of the material when compared to conventional implant devices with either micro- or nano-structured surfaces. (paper)

  18. Synthesis and characterization of hybrid micro/nano-structured NiTi surfaces by a combination of etching and anodizing.

    Science.gov (United States)

    Huan, Z; Fratila-Apachitei, L E; Apachitei, I; Duszczyk, J

    2014-02-07

    The purpose of this study was to generate hybrid micro/nano-structures on biomedical nickel-titanium alloy (NiTi). To achieve this, NiTi surfaces were firstly electrochemically etched and then anodized in fluoride-containing electrolyte. With the etching process, the NiTi surface was micro-roughened through the formation of micropits uniformly distributed over the entire surface. Following the subsequent anodizing process, self-organized nanotube structures enriched in TiO2 could be superimposed on the etched surface under specific conditions. Furthermore, the anodizing treatment significantly reduced water contact angles and increased the surface free energy compared to the surfaces prior to anodizing. The results of this study show for the first time that it is possible to create hybrid micro/nano-structures on biomedical NiTi alloys by combining electrochemical etching and anodizing under controlled conditions. These novel structures are expected to significantly enhance the surface biofunctionality of the material when compared to conventional implant devices with either micro- or nano-structured surfaces.

  19. Superhydrophilicity of a nanofiber-covered aluminum surface fabricated via pyrophosphoric acid anodizing

    Science.gov (United States)

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

    2016-12-01

    A superhydrophilic aluminum surface covered by numerous alumina nanofibers was fabricated via pyrophosphoric acid anodizing. High-density anodic alumina nanofibers grow on the bottom of a honeycomb oxide via anodizing in concentrated pyrophosphoric acid. The water contact angle on the nanofiber-covered aluminum surface decreased with time after a 4 μL droplet was placed on the surface, and a superhydrophilic behavior with a contact angle measuring 2.2° was observed within 2 s; this contact angle is considerably lower than those observed for electropolished and porous alumina-covered aluminum surfaces. There was no dependence of the superhydrophilicity on the density of alumina nanofibers fabricated via different constant voltage anodizing conditions. The superhydrophilic property of the surface covered by anodic alumina nanofibers was maintained during an exposure test for 359 h. The quick-drying and snow-sliding behaviors of the superhydrophilic aluminum covered with anodic alumina nanofibers were demonstrated.

  20. Preparation of self-organized porous anodic niobium oxide microcones and their surface wettability

    International Nuclear Information System (INIS)

    Oikawa, Y.; Minami, T.; Mayama, H.; Tsujii, K.; Fushimi, K.; Aoki, Y.; Skeldon, P.; Thompson, G.E.; Habazaki, H.

    2009-01-01

    Porous anodic niobium oxide with a pore size of ∼10 nm was formed at 10 V in glycerol electrolyte containing 0.6 mol dm -3 K 2 HPO 4 and 0.2 mol dm -3 K 3 PO 4 at 433 K. After prolonged anodizing for 5.4 ks, niobium oxide microcones develop on the surface. X-ray diffraction patterns of the anodized specimens revealed that the initially formed anodic oxide is amorphous, but an amorphous-to-crystalline transition occurs during anodizing. As a consequence of the preferential chemical dissolution of the initially formed amorphous oxide, due to different solubility of the amorphous and crystalline oxides, crystalline oxide microcones appear on the film surface after prolonged anodizing. The surface is superhydrophilic. After coating with fluorinated alkylsilane, the surface becomes superhydrophobic with a contact angle of 158 o for water. The surface is also oil repellent, with a contact angle as high as 140 o for salad oil.

  1. Mirror-finished superhydrophobic aluminum surfaces modified by anodic alumina nanofibers and self-assembled monolayers

    Science.gov (United States)

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

    2018-05-01

    We demonstrate mirror-finished superhydrophobic aluminum surfaces fabricated via the formation of anodic alumina nanofibers and subsequent modification with self-assembled monolayers (SAMs). High-density anodic alumina nanofibers were formed on the aluminum surface via anodizing in a pyrophosphoric acid solution. The alumina nanofibers became tangled and bundled by further anodizing at low temperature because of their own weight, and the aluminum surface was completely covered by the long falling nanofibers. The nanofiber-covered aluminum surface exhibited superhydrophilic behavior, with a contact angle measuring less than 10°. As the nanofiber-covered aluminum surface was modified with n-alkylphosphonic acid SAMs, the water contact angle drastically shifted to superhydrophobicity, measuring more than 150°. The contact angle increased with the applied voltage during pyrophosphoric acid anodizing, the anodizing time, and the number of carbon atoms contained in the SAM molecules modified on the alumina nanofibers. By optimizing the anodizing and SAM-modification conditions, superhydrophobic behavior could be achieved with only a brief pyrophosphoric acid anodizing period of 3 min and subsequent simple immersion in SAM solutions. The superhydrophobic aluminum surface exhibited a high reflectance, measuring approximately 99% across most of the visible spectrum, similar to that of an electropolished aluminum surface. Therefore, our mirror-finished superhydrophobic aluminum surface based on anodic alumina nanofibers and SAMs can be used as a reflective mirror in various optical applications such as concentrated solar power systems.

  2. Proportional counter with a wire-anode lying on the dielectric surface

    International Nuclear Information System (INIS)

    Strelkov, A.V.

    1983-01-01

    Proportional coUnter with wire-anode lying on the dielectric surface is described. The result of the accumulation of charges on the dielectric surface immediately near the wire-anode surface is that such a counter possesses electrostatic memory relative to distribution of the gas amplification coefficient along the anode. SUch a distribution can be received for example by means of irradiation by the neutrons or the γ-rays. The disposition of the wire-anode on the convex dielectric surface allows one to make the ring-shaped counters or the nonplane proportional chambers practically of any profile. However, the energy resolution of the counter with anode on the dielectric is worse than the resolution of counter with free anode particularly at the large gas amplification coefficient

  3. Modeling of the anode surface deformation in high-current vacuum arcs with AMF contacts

    International Nuclear Information System (INIS)

    Huang, Xiaolong; Wang, Lijun; Deng, Jie; Jia, Shenli; Qin, Kang; Shi, Zongqian

    2016-01-01

    A high-current vacuum arc subjected to an axial magnetic field is maintained in a diffuse status. With an increase in arc current, the energy carried by the arc column to the anode becomes larger and finally leads to the anode temperature exceeding the melting point of the anode material. When the anode melting pool is formed, and the rotational plasma of the arc column delivers its momentum to the melting pool, the anode melting pool starts to rotate and also flow outwards along the radial direction, which has been photographed by some researchers using high-speed cameras. In this paper, the anode temperature and melting status is calculated using the melting and solidification model. The swirl flow of the anode melting pool and deformation of the anode is calculated using the magneto-hydrodynamic (MHD) model with the volume of fraction (VOF) method. All the models are transient 2D axial-rotational symmetric models. The influence of the impaction force of the arc plasma, electromagnetic force, viscosity force, and surface tension of the liquid metal are all considered in the model. The heat flux density injected into the anode and the arc pressure are obtained from the 3D numerical simulation of the high-current vacuum arc using the MHD model, which gives more realistic parameters for the anode simulation. Simulation results show that the depth of the anode melting pool increases with an increase in the arc current. Some droplets sputter out from the anode surface, which is caused by the inertial centrifugal force of the rotational melting pool and strong plasma pressure. Compared with the previous anode melting model without consideration of anode deformation, when the deformation and swirl flow of the anode melting pool are considered, the anode temperature is relatively lower, and just a little more than the melting point of Cu. This is because of liquid droplets sputtering out of the anode surface taking much of the energy away from the anode surface. The

  4. Microstructure and optical appearance of anodized friction stir processed Al - Metal oxide surface composites

    DEFF Research Database (Denmark)

    Gudla, Visweswara Chakravarthy; Jensen, Flemming; Bordo, Kirill

    2014-01-01

    Multiple-pass friction stir processing (FSP) was employed to impregnate Ti, Y and Ce oxide powders into the surface of an Aluminium alloy. The FSP processed surface composite was subsequently anodized with an aim to develop optical effects in the anodized layer owing to the presence of incorporated...... oxide particles which will influence the scattering of light. This paper presents the investigations on relation between microstructure of the FSP zone and optical appearance of the anodized layer due to incorporation of metal oxide particles and modification of the oxide particles due to the anodizing...

  5. Advanced Surface and Microstructural Characterization of Natural Graphite Anodes for Lithium Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Gallego, Nidia C [ORNL; Contescu, Cristian I [ORNL; Meyer III, Harry M [ORNL; Howe, Jane Y [ORNL; Meisner, Roberta Ann [ORNL; Payzant, E Andrew [ORNL; Lance, Michael J [ORNL; Yoon, Steve [A123 Systems, Inc.; Denlinger, Matthew [A123 Systems, Inc.; Wood III, David L [ORNL

    2014-01-01

    Natural graphite powders were subjected to a series of thermal treatments in order to improve the anode irreversible capacity loss (ICL) and capacity retention during long-term cycling of lithium ion batteries. A baseline thermal treatment in inert Ar or N2 atmosphere was compared to cases with a proprietary additive to the furnace gas environment. This additive substantially altered the surface chemistry of the natural graphite powders and resulted in significantly improved long-term cycling performance of the lithium ion batteries over the commercial natural graphite baseline. Different heat-treatment temperatures were investigated ranging from 950-2900 C with the intent of achieving the desired long-term cycling performance with as low of a maximum temperature and thermal budget as possible. A detailed summary of the characterization data is also presented, which includes X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and temperature-programed desorption mass spectroscopy (TPD-MS). This characterization data was correlated to the observed capacity fade improvements over the course of long-term cycling at high charge-discharge rates in full lithium-ion coin cells. It is believed that the long-term performance improvements are a result of forming a more stable solid electrolyte interface (SEI) layer on the anode graphite surfaces, which is directly related to the surface chemistry modifications imparted by the proprietary gas environment during thermal treatment.

  6. Surface analysis of Li-ion battery model anodes

    Energy Technology Data Exchange (ETDEWEB)

    Seemayer, Andreas; Bach, Philipp; Renner, Frank Uwe [Max Planck Institut fuer Eisenforschung GmbH, Max-Planck-Str. 1, 40237 Duesseldorf (Germany)

    2011-07-01

    Lithium ion batteries are the most promising power source for future electromobility applications. Research on the battery systems aims to achieve higher rate capability, cycle life, or better safety. To achieve necessary further improvements a better understanding of the basic processes is needed. Following a surface science approach we focus on the investigation of simple model systems (like single crystals or thin film electrodes) of relevant anode materials. We report investigations of the electrochemical insertion of lithium in Au, Ag, Al, Mg and Si model surfaces, i.e. alloying and dealloying of lithium alloys. As electrolyte we use the ionic liquid 1-Butyl-1-methylpyrrolidinium bis(trifluoromethanesolfonyl)imide (PYR14TFSI) with 0.3M LiTFSI. The electrochemical characterisation is performed by cyclic voltammetry (CV). The surface and film characterisation regarding its geometrical structure is investigated by means of scanning electron microscopy (SEM) and Atomic Force Microscopy (AFM). The chemical composition is characterised ex-situ by photoelectron spectroscopy (PES) and secondary ion mass spectrometry (SIMS).

  7. Electrolyte effects on the surface chemistry and cellular response of anodized titanium

    International Nuclear Information System (INIS)

    Ohtsu, Naofumi; Kozuka, Taro; Hirano, Mitsuhiro; Arai, Hirofumi

    2015-01-01

    Highlights: • Ti samples were anodized using various electrolytes. • Anodization decreased carbon adsorption, improving hydrophilicity. • Improved hydrophilicity led to improved cellular attachment. • Only one electrolyte showed any heteroatom incorporation into the TiO 2 layer. • Choice of electrolyte played no role on the effects of anodization. - Abstract: Anodic oxidation of titanium (Ti) material is used to enhance biocompatibility, yet the effects of various electrolytes on surface characteristics and cellular behavior have not been completely elucidated. To investigate this topic, oxide layers were produced on Ti substrates by anodizing them in aqueous electrolytes of (NH 4 ) 2 O·5B 2 O 3 , (NH 4 ) 2 SO 4 , or (NH 4 ) 3 PO 4 , after which their surface characteristics and cellular responses were examined. Overall, no surface differences between the electrolytes were visually observed. X-ray photoelectron spectroscopy (XPS) revealed that the anodized surfaces are composed of titanium dioxide (TiO 2 ), while incorporation from electrolyte was only observed for (NH 4 ) 3 PO 4 . Surface adsorption of carbon contaminants during sterilization was suppressed by anodization, leading to lower water contact angles. The attachment of MC3T3-E1 osteoblast-like cells was also improved by anodization, as evidenced by visibly enlarged pseudopods. This improved attachment performance is likely due to TiO 2 formation. Overall, electrolyte selection showed no effect on either surface chemistry or cellular response of Ti materials

  8. Histomorphometric and histologic evaluation of titanium-zirconium (aTiZr) implants with anodized surfaces.

    Science.gov (United States)

    Sharma, Ajay; McQuillan, A James; Shibata, Yo; Sharma, Lavanya A; Waddell, John Neil; Duncan, Warwick John

    2016-05-01

    The choice of implant surface has a significant influence on osseointegration. Modification of TiZr surface by anodization is reported to have the potential to modulate the osteoblast cell behaviour favouring more rapid bone formation. The aim of this study is to investigate the effect of anodizing the surface of TiZr discs with respect to osseointegration after four weeks implantation in sheep femurs. Titanium (Ti) and TiZr discs were anodized in an electrolyte containing DL-α-glycerophosphate and calcium acetate at 300 V. The surface characteristics were analyzed by scanning electron microscopy, electron dispersive spectroscopy, atomic force microscopy and goniometry. Forty implant discs with thickness of 1.5 and 10 mm diameter (10 of each-titanium, titanium-zirconium, anodized titanium and anodized titanium-zirconium) were placed in the femoral condyles of 10 sheep. Histomorphometric and histologic analysis were performed 4 weeks after implantation. The anodized implants displayed hydrophilic, porous, nano-to-micrometer scale roughened surfaces. Energy dispersive spectroscopy analysis revealed calcium and phosphorous incorporation into the surface of both titanium and titanium-zirconium after anodization. Histologically there was new bone apposition on all implanted discs, slightly more pronounced on anodised discs. The percentage bone-to-implant contact measurements of anodized implants were higher than machined/unmodified implants but there was no significant difference between the two groups with anodized surfaces (P > 0.05, n = 10). The present histomorphometric and histological findings confirm that surface modification of titanium-zirconium by anodization is similar to anodised titanium enhances early osseointegration compared to machined implant surfaces.

  9. Fabrication of the superhydrophobic surface on aluminum alloy by anodizing and polymeric coating

    Science.gov (United States)

    Liu, Wenyong; Luo, Yuting; Sun, Linyu; Wu, Ruomei; Jiang, Haiyun; Liu, Yuejun

    2013-01-01

    We reported the preparation of the superhydrophobic surface on aluminum alloy via anodizing and polymeric coating. Both the different anodizing processes and different polymeric coatings of aluminum alloy were investigated. The effects of different anodizing conditions, such as electrolyte concentration, anodization time and current on the superhydrophobic surface were discussed. The results showed that a good superhydrophobic surface was facilely fabricated by polypropylene (PP) coating after anodizing. The optimum conditions for anodizing were determined by orthogonal experiments. When the concentration of oxalic acid was 10 g/L, the concentration of NaCl was 1.25 g/L, anodization time was 40 min, and anodization current was 0.4 A, the best superhydrophobic surface on aluminum alloy with the contact angle (CA) of 162° and the sliding angle of 2° was obtained. On the other hand, the different polymeric coatings, such as polystyrene (PS), polypropylene (PP) and polypropylene grafting maleic anhydride (PP-g-MAH) were used to coat the aluminum alloy surface after anodizing. The results showed that the superhydrophobicity was most excellent by coating PP, while the duration of the hydrophobic surface was poor. By modifying the surface with the silane coupling agent before PP coating, the duration of the superhydrophobic surface was improved. The morphologies of the superhydrophobic surface were further confirmed by optical microscope (OM) and scanning electron microscope (SEM). Combined with the material of PP with the low surface free energy, the micro/nano-structures of the surface resulted in the superhydrophobicity of the aluminum alloy surface.

  10. Fabrication of the superhydrophobic surface on aluminum alloy by anodizing and polymeric coating

    Energy Technology Data Exchange (ETDEWEB)

    Liu Wenyong, E-mail: lwy@iccas.ac.cn [Key Laboratory of Advanced Materials and Technology for Packaging, Hunan University of Technology, Zhuzhou 412007 (China); College of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007 (China); Luo Yuting; Sun Linyu [College of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007 (China); Wu Ruomei, E-mail: cailiaodian2004@126.com [College of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007 (China); Jiang Haiyun [College of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007 (China); Liu Yuejun [Key Laboratory of Advanced Materials and Technology for Packaging, Hunan University of Technology, Zhuzhou 412007 (China); College of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007 (China)

    2013-01-01

    Graphical abstract: The hydrophobic surface on aluminum alloy fabricated by anodizing and polymeric coating. Highlights: Black-Right-Pointing-Pointer Anodizing and polymeric coating were used to prepare a superhydrophobic surface on aluminum alloy. Black-Right-Pointing-Pointer Superhydrophobic surfaces with a high water contact angle of 162 Degree-Sign and a low rolling angle of 2 Degree-Sign were obtained. Black-Right-Pointing-Pointer The method is facile, and the materials are inexpensive, and is expected to be used widely. - Abstract: We reported the preparation of the superhydrophobic surface on aluminum alloy via anodizing and polymeric coating. Both the different anodizing processes and different polymeric coatings of aluminum alloy were investigated. The effects of different anodizing conditions, such as electrolyte concentration, anodization time and current on the superhydrophobic surface were discussed. The results showed that a good superhydrophobic surface was facilely fabricated by polypropylene (PP) coating after anodizing. The optimum conditions for anodizing were determined by orthogonal experiments. When the concentration of oxalic acid was 10 g/L, the concentration of NaCl was 1.25 g/L, anodization time was 40 min, and anodization current was 0.4 A, the best superhydrophobic surface on aluminum alloy with the contact angle (CA) of 162 Degree-Sign and the sliding angle of 2 Degree-Sign was obtained. On the other hand, the different polymeric coatings, such as polystyrene (PS), polypropylene (PP) and polypropylene grafting maleic anhydride (PP-g-MAH) were used to coat the aluminum alloy surface after anodizing. The results showed that the superhydrophobicity was most excellent by coating PP, while the duration of the hydrophobic surface was poor. By modifying the surface with the silane coupling agent before PP coating, the duration of the superhydrophobic surface was improved. The morphologies of the superhydrophobic surface were further confirmed

  11. Fabrication of the superhydrophobic surface on aluminum alloy by anodizing and polymeric coating

    International Nuclear Information System (INIS)

    Liu Wenyong; Luo Yuting; Sun Linyu; Wu Ruomei; Jiang Haiyun; Liu Yuejun

    2013-01-01

    Graphical abstract: The hydrophobic surface on aluminum alloy fabricated by anodizing and polymeric coating. Highlights: ► Anodizing and polymeric coating were used to prepare a superhydrophobic surface on aluminum alloy. ► Superhydrophobic surfaces with a high water contact angle of 162° and a low rolling angle of 2° were obtained. ► The method is facile, and the materials are inexpensive, and is expected to be used widely. - Abstract: We reported the preparation of the superhydrophobic surface on aluminum alloy via anodizing and polymeric coating. Both the different anodizing processes and different polymeric coatings of aluminum alloy were investigated. The effects of different anodizing conditions, such as electrolyte concentration, anodization time and current on the superhydrophobic surface were discussed. The results showed that a good superhydrophobic surface was facilely fabricated by polypropylene (PP) coating after anodizing. The optimum conditions for anodizing were determined by orthogonal experiments. When the concentration of oxalic acid was 10 g/L, the concentration of NaCl was 1.25 g/L, anodization time was 40 min, and anodization current was 0.4 A, the best superhydrophobic surface on aluminum alloy with the contact angle (CA) of 162° and the sliding angle of 2° was obtained. On the other hand, the different polymeric coatings, such as polystyrene (PS), polypropylene (PP) and polypropylene grafting maleic anhydride (PP-g-MAH) were used to coat the aluminum alloy surface after anodizing. The results showed that the superhydrophobicity was most excellent by coating PP, while the duration of the hydrophobic surface was poor. By modifying the surface with the silane coupling agent before PP coating, the duration of the superhydrophobic surface was improved. The morphologies of the superhydrophobic surface were further confirmed by optical microscope (OM) and scanning electron microscope (SEM). Combined with the material of PP with the low

  12. Reduced adhesion of macrophages on anodized titanium with select nanotube surface features

    Directory of Open Access Journals (Sweden)

    Balasubramanian K

    2011-08-01

    Full Text Available Amancherla Rajyalakshmi1, Batur Ercan2,3, K Balasubramanian1, Thomas J Webster2,31Non-Ferrous Materials Technology Development Centre, Hyderabad, India; 2School of Engineering, 3Department of Orthopedics, Brown University, Providence, RI, USAAbstract: One of the important prerequisites for a successful orthopedic implant apart from being osteoconductive is the elicitation of a favorable immune response that does not lead to the rejection of the implant by the host tissue. Anodization is one of the simplest surface modification processes used to create nanotextured and nanotubular features on metal oxides which has been shown to improve bone formation. Anodization of titanium (Ti leads to the formation of TiO2 nanotubes on the surface, and the presence of these nanotubes mimics the natural nanoscale features of bone, which in turn contributes to improved bone cell attachment, migration, and proliferation. However, inflammatory cell responses on anodized Ti remains to be tested. It is hypothesized that surface roughness and surface feature size on anodized Ti can be carefully manipulated to control immune cell (specifically, macrophages responses. Here, when Ti samples were anodized at 10 V in the presence of 1% hydrofluoric acid (HF for 1 minute, nanotextured (nonnanotube surfaces were created. When anodization of Ti samples was carried out with 1% HF for 10 minutes at 15 V, nanotubes with 40–50 nm diameters were formed, whereas at 20 V with 1% HF for 10 minutes, nanotubes with 60–70 nm diameters were formed. In this study, a reduced density of macrophages was observed after 24 hours of culture on nanotextured and nanotubular Ti samples which were anodized at 10, 15, and 20 V, compared with conventional unmodified Ti samples. This in vitro study thus demonstrated a reduced density of macrophages on anodized Ti, thereby providing further evidence of the greater efficacy of anodized Ti for orthopedic applications.Keywords: anodization, titanium

  13. Optimal condition for fabricating superhydrophobic Aluminum surfaces with controlled anodizing processes

    Science.gov (United States)

    Saffari, Hamid; Sohrabi, Beheshteh; Noori, Mohammad Reza; Bahrami, Hamid Reza Talesh

    2018-03-01

    A single step anodizing process is used to produce micro-nano structures on Aluminum (1050) substrates with sulfuric acid as electrolyte. Therefore, surface energy of the anodized layer is reduced using stearic acid modification. Undoubtedly, effects of different parameters including anodizing time, electrical current, and type and concentration of electrolyte on the final contact angle are systemically studied and optimized. Results show that anodizing current of 0.41 A, electrolyte (sulfuric acid) concentration of 15 wt.% and anodizing time of 90 min are optimal conditions which give contact angle as high as 159.2° and sliding angle lower than 5°. Moreover, the study reveals that adding oxalic acid to the sulfuric acid cannot enhance superhydrophobicity of the samples. Also, scanning electron microscopy images of samples show that irregular (bird's nest) structures present on the surface instead of high-ordered honeycomb structures expecting from normal anodizing process. Additionally, X-ray diffraction analysis of the samples shows that only amorphous structures present on the surface. The Brunauer-Emmett-Teller (BET) specific surface area of the anodized layer is 2.55 m2 g-1 in optimal condition. Ultimately, the surface keeps its hydrophobicity in air and deionized water (DIW) after one week and 12 weeks, respectively.

  14. Surface treatments for aluminium alloys

    Science.gov (United States)

    Ardelean, M.; Lascău, S.; Ardelean, E.; Josan, A.

    2018-01-01

    Typically, in contact with the atmosphere, the aluminium surface is covered with an aluminium oxide layer, with a thickness of less than 1-2μm. Due to its low thickness, high porosity and low mechanical strength, this layer does not protect the metal from corrosion. Anodizing for protective and decorative purposes is the most common method of superficial oxidation processes and is carried out through anodic oxidation. The oxide films, resulted from anodizing, are porous, have a thickness of 20-50μm, and are heat-resistant, stable to water vapour and other corrosion agents. Hard anodizing complies with the same obtains principles as well as decorative and protective anodization. The difference is in that hard anodizing is achieved at low temperatures and high intensity of electric current. In the paper are presented the results of decorative and hard anodization for specimens made from several aluminium alloys in terms of the appearance of the specimens and of the thickness of the anodized.

  15. Friction stir processed Al - Metal oxide surface composites: Anodization and optical appearance

    DEFF Research Database (Denmark)

    Gudla, Visweswara Chakravarthy; Jensen, Flemming; Canulescu, Stela

    2014-01-01

    Multiple-pass friction stir processing (FSP) was employed to impregnate metal oxide (TiO2, Y2O3 and CeO2) particles into the surface of an Aluminium alloy. The surface composites were then anodized in a sulphuric acid electrolyte. The effect of anodizing parameters on the resulting optical...... dark to greyish white. This is attributed to the localized microstructural and morphological differences around the metal oxide particles incorporated into the anodic alumina matrix. The metal oxide particles in the FSP zone electrochemically shadowed the underlying Al matrix and modified the local...

  16. Highly reversible lead-carbon battery anode with lead grafting on the carbon surface

    KAUST Repository

    Yin, Jian; Lin, Nan; Zhang, Wenli; Lin, Zheqi; Zhang, Ziqing; Wang, Yue; Shi, Jun; Bao, Jinpeng; Lin, Haibo

    2018-01-01

    A novel C/Pb composite has been successfully prepared by electroless plating to reduce the hydrogen evolution and achieve the high reversibility of the anode of lead-carbon battery (LCB). The deposited lead on the surface of C/Pb composite was found to be uniform and adherent to carbon surface. Because lead has been stuck on the surface of C/Pb composite, the embedded structure suppresses the hydrogen evolution of lead-carbon anode and strengthens the connection between carbon additive and sponge lead. Compared with the blank anode, the lead-carbon anode with C/Pb composite displays excellent charge–discharge reversibility, which is attributed to the good connection between carbon additives and lead that has been stuck on the surface of C/Pb composite during the preparation process. The addition of C/Pb composite maintains a solid anode structure with high specific surface area and power volume, and thereby, it plays a significant role in the highly reversible lead-carbon anode.

  17. Highly reversible lead-carbon battery anode with lead grafting on the carbon surface

    KAUST Repository

    Yin, Jian

    2018-03-27

    A novel C/Pb composite has been successfully prepared by electroless plating to reduce the hydrogen evolution and achieve the high reversibility of the anode of lead-carbon battery (LCB). The deposited lead on the surface of C/Pb composite was found to be uniform and adherent to carbon surface. Because lead has been stuck on the surface of C/Pb composite, the embedded structure suppresses the hydrogen evolution of lead-carbon anode and strengthens the connection between carbon additive and sponge lead. Compared with the blank anode, the lead-carbon anode with C/Pb composite displays excellent charge–discharge reversibility, which is attributed to the good connection between carbon additives and lead that has been stuck on the surface of C/Pb composite during the preparation process. The addition of C/Pb composite maintains a solid anode structure with high specific surface area and power volume, and thereby, it plays a significant role in the highly reversible lead-carbon anode.

  18. Effect of amorphous fluorinated coatings on photocatalytic properties of anodized titanium surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Persico, Federico [Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, via Mancinelli 7, 20131, Milano (Italy); Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali, Via G. Giusti, 9, 50121 Firenze (Italy); Sansotera, Maurizio, E-mail: maurizio.sansotera@polimi.it [Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, via Mancinelli 7, 20131, Milano (Italy); Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali, Via G. Giusti, 9, 50121 Firenze (Italy); Diamanti, Maria Vittoria [Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, via Mancinelli 7, 20131, Milano (Italy); Magagnin, Luca; Venturini, Francesco; Navarrini, Walter [Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, via Mancinelli 7, 20131, Milano (Italy); Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali, Via G. Giusti, 9, 50121 Firenze (Italy)

    2013-10-31

    The photocatalytic activity promoted by anodized titanium surfaces coated with different amorphous perfluoropolymers was evaluated. A copolymer between tetrafluoroethylene and perfluoro-4-trifluoromethoxy-1,3-dioxole and two perfluoropolyethers containing ammonium phosphate and triethoxysilane functionalities, respectively, were tested as coating materials. These coatings revealed good adhesion to the anodized titanium substrate and conferred to it both hydrophobicity and oleophobicity. The photocatalytic activity of the coating on anodized titanium was evaluated by monitoring the degradation of stearic acid via Infrared spectroscopy. The degradation rate of stearic acid was reduced but not set to zero by the presence of the fluorinated coatings, leading to the development of advanced functional coatings. The morphological variations of the coatings as a result of photocatalysis were also determined by atomic force microscopy. - Highlights: • Coated anodized titanium surfaces show a decreased wettability. • Evaluation of the stability of perfluorinated coatings towards photocatalysis. • Amorphous perfluorinated coatings do not hinder photocatalytic activity.

  19. Fabrication of TiO2 Crystalline Coatings by Combining Ti-6Al-4V Anodic Oxidation and Heat Treatments

    Directory of Open Access Journals (Sweden)

    María Laura Vera

    2015-01-01

    Full Text Available The bio- and hemocompatibility of titanium alloys are due to the formation of a TiO2 layer. This natural oxide may have fissures which are detrimental to its properties. Anodic oxidation is used to obtain thicker films. By means of this technique, at low voltages oxidation, amorphous and low roughness coatings are obtained, while, above a certain voltage, crystalline and porous coatings are obtained. According to the literature, the crystalline phases of TiO2, anatase, and rutile would present greater biocompatibility than the amorphous phase. On the other hand, for hemocompatible applications, smooth and homogeneous surfaces are required. One way to obtain crystalline and homogeneous coatings is by heat treatments after anodic oxidation. The aim of this study is to evaluate the influence of heat treatments on the thickness, morphology, and crystalline structure of the TiO2 anodic coatings. The characterization was performed by optical and scanning electron microscopy, X-ray diffraction, and X-ray reflectometry. Coatings with different colors of interference were obtained. There were no significant changes in the surface morphology and roughness after heat treatment of 500°C. Heat treated coatings have different proportions of the crystalline phases, depending on the voltage of anodic oxidation and the temperature of the heat treatment.

  20. Modelling of crater formation on anode surface by high-current vacuum arcs

    Science.gov (United States)

    Tian, Yunbo; Wang, Zhenxing; Jiang, Yanjun; Ma, Hui; Liu, Zhiyuan; Geng, Yingsan; Wang, Jianhua; Nordlund, Kai; Djurabekova, Flyura

    2016-11-01

    Anode melting and crater formation significantly affect interruption of high-current vacuum arcs. The primary objective of this paper is to theoretically investigate the mechanism of anode surface crater formation, caused by the combined effect of surface heating during the vacuum arc and pressure exerted on the molten surface by ions and electrons from the arc plasma. A model of fluid flow and heat transfer in the arc anode is developed and combined with a magnetohydrodynamics model of the vacuum arc plasma. Crater formation is observed in simulation for a peak arcing current higher than 15 kA on 40 mm diam. Cu electrodes spaced 10 mm apart. The flow of liquid metal starts after 4 or 5 ms of arcing, and the maximum velocities are 0.95 m/s and 1.39 m/s for 20 kA and 25 kA arcs, respectively. This flow redistributes thermal energy, and the maximum temperature of the anode surface does not remain in the center. Moreover, the condition for the liquid droplet formation on the anode surfaces is developed. The solidification process after current zero is also analyzed. The solidification time has been found to be more than 3 ms after 25 kA arcing. The long solidification time and sharp features on crater rims induce Taylor cone formation.

  1. Anodized porous titanium coated with Ni-CeO{sub 2} deposits for enhancing surface toughness and wear resistance

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xiaowei, E-mail: zhouxiaowei901@163.com; Ouyang, Chun

    2017-05-31

    Highlights: • Structural design of anodized nanoporous Ti was introduced for bonding pinholes to achieve a metallurgical bonding interface. • Anodized porous Ti substrate was activated by electroless Ni-P film to be acted as transitional layer to deposit Ni-CeO{sub 2} nanocomposite coatings. • An analytical model was validated for predicting the Ce-rich worn products as a self-lubricant phase for monitoring wear mechanisms. - Abstract: In order to make large improvements of surface toughness and wear resistance for pure titanium (Ti) substrate, anodic titanium oxide (ATO) surface with nanoporous structure was coated with the Ni-CeO{sub 2} nanocomposite coatings. Regarding TiO{sub 2} barrier layer on Ti surface to inhibit its electrochemical activity, pre-treatments were successively processed with anodizing, sensitizing, activating, and then followed by electroless Ni-P film to be acted as an activated layer for electroplating Ni-CeO{sub 2} deposits. The existing Pd atoms around ATO nanopores were expected as the heterogeneous nucleation sites for supporting the growing locations of electroless Ni-P film. The innovative of interface design using porous structure was introduced for bonding pinholes to achieve a metallurgical adhesion interface between Ti substrate and surface coatings. Besides the objectives of this work were to elucidate how effects by the adding CeO{sub 2} nanoparticles on modifying microstructures and wear mechanisms of Ni-CeO{sub 2} nanocomposite coatings. Many efforts of XRD, FE-SEM, TEM and Nanoindentation tests were devoted to comparing different wear behaviors of Ni-CeO{sub 2} coatings relative to pure nickel. Results indicated that uniform-distributed Ti nanopores with an average diameter size of ∼200 nm was achieved using the Phosphate-type anodizing solution at DC 150 V. A worn surface without fatigue cracks was observed for TAO surface coated with Ni-CeO{sub 2} deposits, showing the existing Ce-rich worn products to be acted as a

  2. Fabrication of the micro/nano-structure superhydrophobic surface on aluminum alloy by sulfuric acid anodizing and polypropylene coating.

    Science.gov (United States)

    Wu, Ruomei; Liang, Shuquan; Liu, Jun; Pan, Anqiang; Yu, Y; Tang, Yan

    2013-03-01

    The preparation of the superhydrophobic surface on aluminum alloy by anodizing and polypropylene (PP) coating was reported. Both the different anodizing process and different PP coatings of aluminum alloy were investigated. The effects of different anodizing conditions, such as electrolyte concentration, anodization time and current on the superhydrophobic surface were discussed. By PP coating after anodizing, a good superhydrophobic surface was facilely fabricated. The optimum conditions for anodizing were determined by orthogonal experiments. After the aluminium-alloy was grinded with 600# sandpaper, pretreated by 73 g/L hydrochloric acid solution at 1 min, when the concentration of sulfuric acid was 180 g/L, the concentration of oxalic acid was 5 g/L, the concentration of potassium dichromate was 10 g/L, the concentration of chloride sodium was 50 g/L and 63 g/L of glycerol, anodization time was 20 min, and anodization current was 1.2 A/dm2, anodization temperature was 30-35 degrees C, the best micro-nanostructure aluminum alloy films was obtained. On the other hand, the PP with different concentrations was used to the PP with different concentrations was used to coat the aluminum alloy surface after anodizing. The results showed that the best superhydrophobicity was achieved by coating PP, and the duration of the superhydrophobic surface was improved by modifying the coat the aluminum alloy surface after anodizing. The results showed that the best superhydrophobicity was surface with high concentration PP. The morphologies of micro/nano-structure superhydrophobic surface were further confirmed by scanning electron microscope (SEM). The material of PP with the low surface free energy combined with the micro/nano-structures of the surface resulted in the superhydrophobicity of the aluminum alloy surface.

  3. Influence of heat-treatment on lithium ion anode properties of mesoporous carbons with nanosheet-like walls

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Fanyan [College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Hou, Zhaohui, E-mail: zhqh96@163.com [College of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006 (China); He, Binhong [College of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006 (China); Ge, Chongyong; Cao, Jianguo [College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Kuang, Yafei, E-mail: yafeik@163.com [College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China)

    2012-08-15

    Highlights: ► Mesoporous carbons possess unique nanosheet-like pore walls which can be changed by heat treatment. ► Lithium ion anode properties of mesoporous carbons could be influenced by the nanosheet-like walls. ► Mesoporous carbons with nanosheet-like walls exhibit enhanced electrochemical properties LIBs. -- Abstract: Mesoporous carbons (MCs) with nanosheet-like walls have been prepared as electrodes for lithium-ion batteries by a simple one-step infiltrating method under the action of capillary flow. The influence of heat treatment temperature on the surface topography, pore/phase structure and anode performances of as-prepared materials has been investigated. The results reveal that melted liquid-crystal polycyclic aromatic hydrocarbons could be anchored on liquid/silica interfaces by molecule engineering. After carbonization, the nanosheets are formed as the pore walls of MCs and are perpendicular to the long axis of pores. The anode properties demonstrate that C-1200 displays higher reversible capacitance than those treated in higher temperature. The rate performances of C-1200 and C-1800 are similar and more excellent than that of C-2400. These improved lithium ion anode properties could be attributed to the nanosheet-like walls of MCs which can be influenced by the heat treatment temperature.

  4. In situ formation of graphene layers on graphite surfaces for efficient anodes of microbial fuel cells.

    Science.gov (United States)

    Tang, Jiahuan; Chen, Shanshan; Yuan, Yong; Cai, Xixi; Zhou, Shungui

    2015-09-15

    Graphene can be used to improve the performance of the anode in a microbial fuel cell (MFC) due to its good biocompatibility, high electrical conductivity and large surface area. However, the chemical production and modification of the graphene on the anode are environmentally hazardous because of the use of various harmful chemicals. This study reports a novel method based on the electrochemical exfoliation of a graphite plate (GP) for the in situ formation of graphene layers on the surface of a graphite electrode. When the resultant graphene-layer-based graphite plate electrode (GL/GP) was used as an anode in an MFC, a maximum power density of 0.67 ± 0.034 W/m(2) was achieved. This value corresponds to 1.72-, 1.56- and 1.26-times the maximum power densities of the original GP, exfoliated-graphene-modified GP (EG/GP) and chemically-reduced-graphene-modified GP (rGO/GP) anodes, respectively. Electrochemical measurements revealed that the high performance of the GL/GP anode was attributable to its macroporous structure, improved electron transfer and high electrochemical capacitance. The results demonstrated that the proposed method is a facile and environmentally friendly synthesis technique for the fabrication of high-performance graphene-based electrodes for use in microbial energy harvesting. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Fabrication of free standing anodic titanium oxide membranes with clean surface using recycling process.

    Science.gov (United States)

    Meng, Xianhui; Lee, Tae-Young; Chen, Huiyu; Shin, Dong-Wook; Kwon, Kee-Won; Kwon, Sang Jik; Yoo, Ji-Beom

    2010-07-01

    Large area of self-organized, free standing anodic titanium oxide (ATO) nanotube membranes with clean surfaces were facilely prepared to desired lengths via electrochemical anodization of highly pure Ti sheets in an ethylene glycol electrolyte, with a small amount of NH4F and H2O at 50 V, followed by self-detachment of the ATO membrane from the Ti substrate using recycling processes. In the first anodization step, the nanowire oxide layer existed over the well-arranged ATO nanotube. After sufficiently rinsing with water, the whole ATO layer was removed from the Ti sheet by high pressure N2 gas, and a well-patterned dimple layer with a thickness of about 30 nm existed on the Ti substrate. By using these naturally formed nano-scale pits as templates, in the second and third anodization process, highly ordered, vertically aligned, and free standing ATO membranes with the anodic aluminum oxide (AAO)-like clean surface were obtained. The inter-pore distance and diameter was 154 +/- 2 nm and 91+/- 2 nm, the tube arrays lengths for 25 and 46 hours were 44 and 70 microm, respectively. The present study demonstrates a simple approach to producing high quality, length controllable, large area TiO2 membrane.

  6. Formation of Nanostructures on the Nickel Metal Surface in Ionic Liquid under Anodizing

    Science.gov (United States)

    Lebedeva, O. K.; Root, N. V.; Kultin, D. Yu.; Kalmykov, K. B.; Kustov, L. M.

    2018-05-01

    The formation of nanostructures in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide on the surface of a nickel electrode during anodizing was studied. Hexagonal ordered surface nanostructures were found to form in a narrow range of current densities. The form of the potential transients of the nickel electrode corresponded to the morphology of the nickel surface obtained which was studied by electron microscopy. No other types of nanostructures were found under the electrosynthesis conditions under study.

  7. Analysis of anti-condensation mechanism on superhydrophobic anodic aluminum oxide surface

    International Nuclear Information System (INIS)

    Wu, Yanpeng; Zhang, Chaoying

    2013-01-01

    Wetting theory about superhydrophobic surfaces reveals that hydrophobicity of surfaces has great relationship with surface roughness and surface free energy. Adopt electrochemical plus fluorine silane modified method to prepare superhydrophobic surface on anodic aluminum oxide surface, which not only enhances surface roughness, but also reduces surface free energy, even the static contact angle can reach 159.2° and anti-condensation is authenticated. Based on the experimental findings, analyze the reason of anti-condensation on superhydrophobic surfaces: one is that the density of droplets formed on superhydrophobic surfaces is low and the number of droplets is little; the other is bigger static contact angle and smaller rolling angle on superhydrophobic surfaces make droplets easy to detach on smaller tilt angle. This research can solve some condensation problems of equipment using in HVAC systems, such as heat exchangers in air conditioning system, cold radiation boards, air supply outlets, and so on. Highlights: • Prepare superhydrophobic surface on anodic aluminum oxide surface. • Analyze the reason of anti-condensation on superhydrophobic surfaces. • The density of droplets formed on superhydrophobic surfaces is low. • Droplets on superhydrophobic surfaces are easy to detach. • This research can solve some problems of equipment using in HVAC systems

  8. Post oxygen treatment characteristics of coke as an anode material for Li-ion batteries.

    Science.gov (United States)

    Kim, Jae-Hun; Park, Min-Sik; Jo, Yong Nam; Yu, Ji-Sang; Jeong, Goojin; Kim, Young-Jun

    2013-05-01

    The effect of a oxygen treatment on the electrochemical characteristics of a soft carbon anode material for Li-ion batteries was investigated. After a coke carbonization process at 1000 degrees C in an argon atmosphere, the samples were treated under a flow of oxygen gas to obtain a mild oxidation effect. After this oxygen treatment, the coke samples exhibited an improved initial coulombic efficiency and cycle performance as compared to the carbonized sample. High-resolution transmission electron microscopy revealed that the carbonized cokes consisted of disordered and nanosized graphene layers and the surface of the modified carbon was significantly changed after the treatment. The chemical state of the cokes was analyzed using X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The enhanced electrochemical properties of the surface modified cokes could be attributed to the mild oxidation effect induced by the oxygen treatment. The mild oxidation process could have led to the elimination of surface imperfections and the reinforcement of a solid electrolyte interphase film, which resulted in the improved electrochemical characteristics.

  9. Influence of desiccation procedures on the surface wettability and corrosion resistance of porous aluminium anodic oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Zheng Meng, E-mail: ZhengMeng@eng.hokudai.ac.jp [Graduate School of Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-Ku, Sapporo 060-8628 (Japan); Sakairi, Masatoshi [Faculty of Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-Ku, Sapporo 060-8628 (Japan); Jha, Himendra [Technische Universitaet Muenchen, Lichtenbergstrasse 4, D-85748 Garching (Germany)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Simple desiccation treatment without coating or etching produces hydrophobicity of porous anodic oxide film. Black-Right-Pointing-Pointer Treatment time can be shortened by controlling desiccation condition. Black-Right-Pointing-Pointer Surface microstructure is the key point to determine the wettability. Black-Right-Pointing-Pointer The hydrophobic surfaces show better corrosion resistance than oxide aluminium. - Abstract: A hydrophobic oxide film was formed on aluminium by anodizing followed by desiccation treatment. Films subjected to gradual heating and cooling exhibit larger water contact angles than samples exposed to fast heating and cooling at the same temperature. From SEM and Auger Electron Spectroscopic observations, the low wettability surface shows a regular porous morphology with no significant chemical composition differences due to the different treatments. The desiccation process improves the corrosion resistance, shown by immersion in NaCl. The change in morphology by the desiccation processes is considered a main reason to lower the wettability, which further affects the corrosion properties.

  10. The corrosion protection of aluminum by various anodizing treatments

    Science.gov (United States)

    Danford, Merlin D.

    1989-01-01

    Corrosion protection to 6061-T6 aluminum, afforded by both teflon-impregnated anodized coats (Polylube and Tufram) and hard-anodized coats (water sealed and dichromate sealed), was studied at both pH 5.5 and pH 9.5, with an exposure period of 28 days in 3.5 percent NaCl solution (25 C) for each specimen. In general, corrosion protection for all specimens was better at pH 9.5 than at pH 5.5. Protection by a Tufram coat proved superior to that afforded by Polylube at each pH, with corrosion protection by the hard-anodized, water-sealed coat at pH 9.5 providing the best protection. Electrochemical work in each case was corroborated by microscopic examination of the coats after exposure. Corrosion protection by Tufram at pH 9.5 was most comparable to that of the hard-anodized samples, although pitting and some cracking of the coat did occur.

  11. Silver deposition on titanium surface by electrochemical anodizing process reduces bacterial adhesion of Streptococcus sanguinis and Lactobacillus salivarius.

    Science.gov (United States)

    Godoy-Gallardo, Maria; Rodríguez-Hernández, Ana G; Delgado, Luis M; Manero, José M; Javier Gil, F; Rodríguez, Daniel

    2015-10-01

    The aim of this study was to determine the antibacterial properties of silver-doped titanium surfaces prepared with a novel electrochemical anodizing process. Titanium samples were anodized with a pulsed process in a solution of silver nitrate and sodium thiosulphate at room temperature with stirring. Samples were processed with different electrolyte concentrations and treatment cycles to improve silver deposition. Physicochemical properties were determined by X-ray photoelectron spectroscopy, contact angle measurements, white-light interferometry, and scanning electron microscopy. Cellular cytotoxicity in human fibroblasts was studied with lactate dehydrogenase assays. The in vitro effect of treated surfaces on two oral bacteria strains (Streptococcus sanguinis and Lactobacillus salivarius) was studied with viable bacterial adhesion measurements and growth curve assays. Nonparametric statistical Kruskal-Wallis and Mann-Whitney U-tests were used for multiple and paired comparisons, respectively. Post hoc Spearman's correlation tests were calculated to check the dependence between bacteria adhesion and surface properties. X-ray photoelectron spectroscopy results confirmed the presence of silver on treated samples and showed that treatments with higher silver nitrate concentration and more cycles increased the silver deposition on titanium surface. No negative effects in fibroblast cell viability were detected and a significant reduction on bacterial adhesion in vitro was achieved in silver-treated samples compared with control titanium. Silver deposition on titanium with a novel electrochemical anodizing process produced surfaces with significant antibacterial properties in vitro without negative effects on cell viability. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. New roots to formation of nanostructures on glass surface through anodic oxidation of sputtered aluminum

    Directory of Open Access Journals (Sweden)

    Satoru Inoue, Song-Zhu Chu, Kenji Wada, Di Li and Hajime Haneda

    2003-01-01

    Full Text Available New processes for the preparation of nanostructure on glass surfaces have been developed through anodic oxidation of sputtered aluminum. Aluminum thin film sputtered on a tin doped indium oxide (ITO thin film on a glass surface was converted into alumina by anodic oxidation. The anodic alumina gave nanometer size pore array standing vertically on the glass surface. Kinds of acids used in the anodic oxidation changed the pore size drastically. The employment of phosphoric acid solution gave several tens nanometer size pores. Oxalic acid cases produced a few tens nanometer size pores and sulfuric acid solution provided a few nanometer size pores. The number of pores in a unit area could be changed with varying the applied voltage in the anodization and the pore sizes could be increased by phosphoric acid etching. The specimen consisting of a glass substrate with the alumina nanostructures on the surface could transmit UV and visible light. An etched specimen was dipped in a TiO2 sol solution, resulting in the impregnation of TiO2 sol into the pores of alumina layer. The TiO2 sol was heated at ~400 °C for 2 h, converting into anatase phase TiO2. The specimens possessing TiO2 film on the pore wall were transparent to the light in UV–Visible region. The electro deposition technique was applied to the introduction of Ni metal into pores, giving Ni nanorod array on the glass surface. The removal of the barrier layer alumina at the bottom of the pores was necessary to attain smooth electro deposition of Ni. The photo catalytic function of the specimens possessing TiO2 nanotube array was investigated in the decomposition of acetaldehyde gas under the irradiation of UV light, showing that the rate of the decomposition was quite large.

  13. NH{sub 4}-doped anodic WO{sub 3} prepared through anodization and subsequent NH{sub 4}OH treatment for water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yong-Wook; Kim, Sunkyu; Seong, Mijeong; Yoo, Hyeonseok; Choi, Jinsub, E-mail: jinsub@inha.ac.kr

    2015-01-01

    Highlights: • NN{sub 4}-doped WO{sub 3} was successfully fabricated by a wet-based method using ammonium hydroxide (NH{sub 4}OH). • (NH{sub 4}){sub 10}W{sub 12}O{sub 41} phase was formed during the NH{sub 4}OH treatment. • Over-doped NH{sub 4} in WO{sub 3} led to reduced photo-electrochemical performance for OER. • The optimized surface was achieved by thermal treatment of anodic WO{sub 3} with 2 g of NH{sub 4}OH solution. - Abstract: Tungsten trioxide (WO{sub 3}) prepared by anodization of a W foil was doped with NH{sub 4} through NH{sub 4}OH treatment at 450 °C. Since aqueous NH{sub 4}OH was used during doping instead of NH{sub 3} gas, the treatment step does not require complicated annealing facilities. Moreover, the state of doped N is a form of NH{sub 3}-W instead of W{sub 2}N, which lowers the bandgap but increases photocorrosion. We found that incorporation of NH{sub 4} into WO{sub 3} leads to reduction of the bandgap from 2.9 eV to 2.2 eV, regardless of the amount of NH{sub 4}OH treatment, lowering the onset potential and increasing the current density at fixed potential for oxygen evolution reaction under illumination. Scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy were employed to investigate the surface morphologies, crystallinities of tungsten oxides and existence of NH{sub 4} doping, respectively. The bandgap energy was determined by UV–Vis spectroscopy to measure the transmittance and refraction. The water splitting performance of each sample was measured by electrochemical linear sweep voltammetry in a 3-electrode configuration under illumination.

  14. Surfactant-assisted growth of anodic nanoporous niobium oxide with a grained surface

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jeong Eun [Department of Chemical Engineering, Inha University, 253 Yonghyun Dong, Nam-Gu, Incheon 402-751 (Korea, Republic of); Choi, Jinsub, E-mail: jinsub@inha.ac.k [Department of Chemical Engineering, Inha University, 253 Yonghyun Dong, Nam-Gu, Incheon 402-751 (Korea, Republic of)

    2010-07-15

    Nanoporous niobium oxide film with a maximum thickness of 520 nm was prepared by anodizing niobium in a mixture of 1 wt% HF, 1 M H{sub 3}PO{sub 4}, and a small amount of Sodium Dodecyl Sulfate (SDS) surfactant. The porosity of the anodic niobium oxide prepared without SDS is irregular with the surface of the oxide suggesting a grained surface pattern rather than an ordered porous structure. A proper amount of SDS addition can prepare a pore arrangement with stripe patterns. The pore depth and surface pattern were strongly affected by the concentration of SDS and bath temperature. We found that the addition of SDS surfactant facilitated improvement in the chemical resistance of niobium oxide, leading to the formation of pores with a longer length compared to those prepared without a SDS surfactant. This can be in part ascribed to the protection of the surface by the physical adsorption of SDS on the surface due to a charge-charge interaction and be in part attributed to the formation of Nb=O bonding on the outermost oxide layer by SDS. When anodization was carried out for 4 h, the surface dissolution of niobium oxide was observed, which means that the maximum tolerance time against chemical dissolution was less than 4 h.

  15. Surface analysis of anodized aluminum clamps from NASA-LDEF satellite

    Science.gov (United States)

    Grammer, H. L.; Wightman, J. P.; Young, Philip R.

    1992-01-01

    Surface analysis results of selected anodized aluminum clamps containing black (Z306) and white (A276) paints which received nearly six years of Low Earth Orbit (LEO) exposure on the Long Duration Exposure Facility are reported. Surface analytical techniques, including x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and scanning electron microscopy/energy dispersive analysis by x-ray (SEM/EDAX), showed significant differences in the surface composition of these materials depending upon the position on the LDEF. Differences in the surface composition are attributed to varying amounts of atomic oxygen and vacuum ultraviolet radiation (VUV). Silicon containing compounds were the primary contaminant detected on the materials.

  16. Novel structure formation at the bottom surface of porous anodic alumina fabricated by single step anodization process.

    Science.gov (United States)

    Ali, Ghafar; Ahmad, Maqsood; Akhter, Javed Iqbal; Maqbool, Muhammad; Cho, Sung Oh

    2010-08-01

    A simple approach for the growth of long-range highly ordered nanoporous anodic alumina film in H(2)SO(4) electrolyte through a single step anodization without any additional pre-anodizing procedure is reported. Free-standing porous anodic alumina film of 180 microm thickness with through hole morphology was obtained. A simple and single step process was used for the detachment of alumina from aluminum substrate. The effect of anodizing conditions, such as anodizing voltage and time on the pore diameter and pore ordering is discussed. The metal/oxide and oxide/electrolyte interfaces were examined by high resolution scanning transmission electron microscope. The arrangement of pores on metal/oxide interface was well ordered with smaller diameters than that of the oxide/electrolyte interface. The inter-pore distance was larger in metal/oxide interface as compared to the oxide/electrolyte interface. The size of the ordered domain was found to depend strongly upon anodizing voltage and time. (c) 2010 Elsevier Ltd. All rights reserved.

  17. The effect of anode surface roughness on radiation output for diagnostic x-ray sources

    International Nuclear Information System (INIS)

    Meghzifene, K.; Nowotny, R.; Aiginger, H.

    2002-01-01

    The calculation of entrance surface dose to patients in diagnostic radiology from tube output data is determined by often-unknown sources of inherent filtration. One of these sources is the roughness of the anode surface increasing with tube ageing. This effect increases the inherent filtration of the x-ray tube noticed by a reduced radiation output and increased half-value layers (HVL). To study this effect used rotating anodes were collected and the surface profile of 8 focal tracks was measured in radial direction using an instrument with a diamond tipped stylus (90 deg. tip, 1 μm radius). Surface roughness was determined as the arithmetic mean R a of the deviation in the profile from the centre line for 200 μm reference lengths ranging from 1.32 μm (sandblasted finish without surface degradation) to 5.22 μm (a track for a small focus). The surface profiles were then used to calculate x-ray spectra using a computer code. For each surface about 40000 spectra were calculated with the electrons entering the anode at random position and spectral parameters were then determined. The simulation showed that for rough surfaces the x-rays have to penetrate an additional absorbing layer of tungsten increasing in thickness with anode roughness. The anode with the roughest focal track (R a =5.22 μm) yields a mean additional absorber thickness in direction of the x-ray beam of about 18 μm. The corresponding loss in air kerma for this anode was about 20% at 70 kVp. The effect on mean photon energy is rather small but highest at 70 kVp (+1 keV at R a =5.22 μm) and lowest at 140 kVp (∼0 keV). This is due to the K-edge in the attenuation coefficients of tungsten at 69.5 keV. Beam hardening is thus reduced for higher voltages as absorption at lower photon energies is balanced by higher absorption above the K-edge while at lower voltages beam hardening is fully effective. The pattern of changes in HVL is more complex but in essence also reflects voltage, roughness and

  18. Forming gas treatment of lithium ion battery anode graphite powders

    Science.gov (United States)

    Contescu, Cristian Ion; Gallego, Nidia C; Howe, Jane Y; Meyer, III, Harry M; Payzant, Edward Andrew; Wood, III, David L; Yoon, Sang Young

    2014-09-16

    The invention provides a method of making a battery anode in which a quantity of graphite powder is provided. The temperature of the graphite powder is raised from a starting temperature to a first temperature between 1000 and 2000.degree. C. during a first heating period. The graphite powder is then cooled to a final temperature during a cool down period. The graphite powder is contacted with a forming gas during at least one of the first heating period and the cool down period. The forming gas includes H.sub.2 and an inert gas.

  19. Environmentally Benign Sol-Gel Surface Treatment for Aluminum Bonding Applications

    National Research Council Canada - National Science Library

    Osborne, Joseph

    1996-01-01

    A surface treatment process for aluminum using sol-gel chemistry has been developed that produces strong adhesive bonds without the rinse water requirements of traditional anodizing or etching processes...

  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. Surface chemistry and morphology of the solid electrolyte interphase on silicon nanowire lithium-ion battery anodes

    KAUST Repository

    Chan, Candace K.; Ruffo, Riccardo; Hong, Seung Sae; Cui, Yi

    2009-01-01

    Silicon nanowires (SiNWs) have the potential to perform as anodes for lithium-ion batteries with a much higher energy density than graphite. However, there has been little work in understanding the surface chemistry of the solid electrolyte

  2. Application of anodizing as a pre-treatment for nickel plating on aluminum

    International Nuclear Information System (INIS)

    Mehmood, M.; Ahmad, J.; Aslam, M.; Iqbal, M.; Akhtar, J.I.

    2003-01-01

    Effect of anodizing on subsequent electroplating of nickel on aluminum was investigated. Electroplated nickel did not exhibit any adhesion with un-anodized aluminum. Formation of a very thin anodized alumina film prior to nickel plating led to an excellent adhesion between the nickel film and the substrate. If the thickness of the alumina film increased, adhesion of electroplated nickel was significantly deteriorated and became similar to that of un-anodized bare aluminum. The study revealed that deposition proceeded through pores and defects in the insulator alumina film. These pores and defects also acted as nucleation and anchor points for nickel deposit. There was larger number of nucleation/ anchor points on thin alumina films. This provided better adhesion of nickel with the substrate as well as excellent coverage in relatively shorter times. On the other hand, very rough and poorly adherent nickel deposits formed on thick anodized films. Therefore, it may be used as precursor for producing nickel powder with controlled particle size as well as a catalyst with high specific surface area for hydrogenation and dehydrogenation reactions. (author)

  3. Quantifying the effect of anode surface roughness on diagnostic x-ray spectra using Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Mehranian, A.; Ay, M. R.; Alam, N. Riyahi; Zaidi, H. [Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, P.O. Box 14155-6447, Tehran (Iran, Islamic Republic of) and Research Center for Science and Technology in Medicine, Tehran University of Medical Sciences, P.O. Box 14185-615, Tehran (Iran, Islamic Republic of); Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, P.O. Box 14155-6447, Tehran (Iran, Islamic Republic of); Research Center for Science and Technology in Medicine, Tehran University of Medical Sciences, P.O. Box 14185-615, Tehran (Iran, Islamic Republic of) and Research Institute for Nuclear Medicine, Tehran University of Medical Sciences, P.O. Box 14155-6447, Tehran (Iran, Islamic Republic of); Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, P.O. Box 14155-6447, Tehran (Iran, Islamic Republic of); Division of Nuclear Medicine, Geneva University Hospital, CH-1211 Geneva (Switzerland) and Geneva Neuroscience Center, Geneva University, CH-1205 Geneva (Switzerland)

    2010-02-15

    Purpose: The accurate prediction of x-ray spectra under typical conditions encountered in clinical x-ray examination procedures and the assessment of factors influencing them has been a long-standing goal of the diagnostic radiology and medical physics communities. In this work, the influence of anode surface roughness on diagnostic x-ray spectra is evaluated using MCNP4C-based Monte Carlo simulations. Methods: An image-based modeling method was used to create realistic models from surface-cracked anodes. An in-house computer program was written to model the geometric pattern of cracks and irregularities from digital images of focal track surface in order to define the modeled anodes into MCNP input file. To consider average roughness and mean crack depth into the models, the surface of anodes was characterized by scanning electron microscopy and surface profilometry. It was found that the average roughness (R{sub a}) in the most aged tube studied is about 50 {mu}m. The correctness of MCNP4C in simulating diagnostic x-ray spectra was thoroughly verified by calling its Gaussian energy broadening card and comparing the simulated spectra with experimentally measured ones. The assessment of anode roughness involved the comparison of simulated spectra in deteriorated anodes with those simulated in perfectly plain anodes considered as reference. From these comparisons, the variations in output intensity, half value layer (HVL), heel effect, and patient dose were studied. Results: An intensity loss of 4.5% and 16.8% was predicted for anodes aged by 5 and 50 {mu}m deep cracks (50 kVp, 6 deg. target angle, and 2.5 mm Al total filtration). The variations in HVL were not significant as the spectra were not hardened by more than 2.5%; however, the trend for this variation was to increase with roughness. By deploying several point detector tallies along the anode-cathode direction and averaging exposure over them, it was found that for a 6 deg. anode, roughened by 50 {mu}m deep

  4. Pre-treatment of pyridine wastewater by new cathodic-anodic-electrolysis packing.

    Science.gov (United States)

    Jin, Yang; Yue, Qinyan; Yang, Kunlun; Wu, Suqing; Li, Shengjie; Gao, Baoyu; Gao, Yuan

    2018-01-01

    A novel cathodic-anodic-electrolysis packing (CAEP) used in the treatment of pyridine wastewater was researched, which mainly consisted of 4,4'-diamino-2,2'-disulfonic acid (DSD acid) industrial iron sludge. The physical properties and morphology of the packing were studied. The CAEP was used in a column reactor during the pretreatment of pyridine wastewater. The influence of pH, hydraulic retention time (HRT), the air-liquid ratio (A/L) and the initial concentration of pyridine were investigated by measuring the removal of total organic carbon (TOC) and pyridine. The characterization results showed that the bulk density, grain density, water absorption percentage and specific surface area were 921kg/m 3 , 1086kg/m 3 , 25% and 29.89m 2 /g, respectively; the removal of TOC and pyridine could reach 50% and 58% at the optimal experimental conditions (pH=3, HRT=8hr, A/L=2). Notably, the surface of the packing was renewed constantly during the running of the filter, and the handling capacity was stable after running for three months. Copyright © 2017. Published by Elsevier B.V.

  5. Effect of atomic layer deposition coatings on the surface structure of anodic aluminum oxide membranes.

    Science.gov (United States)

    Xiong, Guang; Elam, Jeffrey W; Feng, Hao; Han, Catherine Y; Wang, Hsien-Hau; Iton, Lennox E; Curtiss, Larry A; Pellin, Michael J; Kung, Mayfair; Kung, Harold; Stair, Peter C

    2005-07-28

    Anodic aluminum oxide (AAO) membranes were characterized by UV Raman and FT-IR spectroscopies before and after coating the entire surface (including the interior pore walls) of the AAO membranes by atomic layer deposition (ALD). UV Raman reveals the presence of aluminum oxalate in bulk AAO, both before and after ALD coating with Al2O3, because of acid anion incorporation during the anodization process used to produce AAO membranes. The aluminum oxalate in AAO exhibits remarkable thermal stability, not totally decomposing in air until exposed to a temperature >900 degrees C. ALD was used to cover the surface of AAO with either Al2O3 or TiO2. Uncoated AAO have FT-IR spectra with two separate types of OH stretches that can be assigned to isolated OH groups and hydrogen-bonded surface OH groups, respectively. In contrast, AAO surfaces coated by ALD with Al2O3 display a single, broad band of hydrogen-bonded OH groups. AAO substrates coated with TiO2 show a more complicated behavior. UV Raman results show that very thin TiO2 coatings (1 nm) are not stable upon annealing to 500 degrees C. In contrast, thicker coatings can totally cover the contaminated alumina surface and are stable at temperatures in excess of 500 degrees C.

  6. Treatment of winery wastewater by anodic oxidation using BDD electrode.

    Science.gov (United States)

    Candia-Onfray, Christian; Espinoza, Nicole; Sabino da Silva, Evanimek B; Toledo-Neira, Carla; Espinoza, L Carolina; Santander, Rocío; García, Verónica; Salazar, Ricardo

    2018-05-04

    The effective removal of organics from winery wastewater was obtained in real residual effluents from the wine industry using anodic oxidation (AO). The effluent had an initial organic load of [COD] 0 of 3490 mg L -1 equal to [TOC] 0 of 1320 mg L -1 . In addition, more than 40 organic compounds were identified by means of GC-MS. Different density currents as well as the addition of electrolytes were tested during electrolysis. The results show the decay of [COD] t by 63.6% when no support electrolyte was added, whereas almost total mineralization and disinfection was reached after adding of 50 mM of sodium sulfate and sodium chloride and applying higher density currents. The presence of sulfate and chloride in large concentration favors the production of oxidants such as hydroxyl radicals and active chlorine species that react with organics in solution. Moreover, the addition of a supporting electrolyte to industrial wastewater increases conductivity, reduces cell potential and therefore, decreases the energy consumption of the AO process. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. Enhanced photoelectrochemical water splitting performance of anodic TiO(2) nanotube arrays by surface passivation.

    Science.gov (United States)

    Gui, Qunfang; Xu, Zhen; Zhang, Haifeng; Cheng, Chuanwei; Zhu, Xufei; Yin, Min; Song, Ye; Lu, Linfeng; Chen, Xiaoyuan; Li, Dongdong

    2014-10-08

    One-dimensional anodic titanium oxide nanotube (TONT) arrays provide a direct pathway for charge transport, and thus hold great potential as working electrodes for electrochemical energy conversion and storage devices. However, the prominent surface recombination due to the large amount surface defects hinders the performance improvement. In this work, the surface states of TONTs were passivated by conformal coating of high-quality Al2O3 onto the tubular structures using atomic layer deposition (ALD). The modified TONT films were subsequently employed as anodes for photoelectrochemical (PEC) water splitting. The photocurrent (0.5 V vs Ag/AgCl) recorded under air mass 1.5 global illumination presented 0.8 times enhancement on the electrode with passivation coating. The reduction of surface recombination rate is responsible for the substantially improved performance, which is proposed to have originated from a decreased interface defect density in combination with a field-effect passivation induced by a negative fixed charge in the Al2O3 shells. These results not only provide a physical insight into the passivation effect, but also can be utilized as a guideline to design other energy conversion devices.

  8. Synergism between anodic oxidation with diamond anodes and heterogeneous catalytic photolysis for the treatment of pharmaceutical pollutants

    Directory of Open Access Journals (Sweden)

    Juan M. Peralta-Hernández

    2016-03-01

    Full Text Available The mineralization of diclofenac and acetaminophen has been studied by single anodic oxidation with boron-doped diamond (AO-BDD using an undivided electrolysis cell, by single heterogeneous catalytic photolysis with titanium dioxide (HCP-TiO2 and by the combination of both advanced oxidation processes. The results show that mineralization can be obtained with either single technology. The type of functional groups of the pollutant does not influence the results of the single AO-BDD process, but it has a significant influence on the results obtained with HCP-TiO2. A clear synergistic effect appears when both processes are combined showing improvements in the oxidation rate of more than 50% for diclofenac and nearly 200% for acetaminophen at the highest current exerted. Results obtained are explained in terms of the production of oxidants on the surface of BDD (primarily peroxodisulfate and the later homogeneous catalytic light decomposition of these oxidants in the bulk. This mechanism is consistent with the larger improvement observed at higher current densities, for which the production of oxidants is promoted.

  9. Advances in aluminum anodizing

    Science.gov (United States)

    Dale, K. H.

    1969-01-01

    White anodize is applied to aluminum alloy surfaces by specific surface preparation, anodizing, pigmentation, and sealing techniques. The development techniques resulted in alloys, which are used in space vehicles, with good reflectance values and excellent corrosive resistance.

  10. Fabrication of a novel aluminum surface covered by numerous high-aspect-ratio anodic alumina nanofibers

    OpenAIRE

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

    2015-01-01

    The formation behavior of anodic alumina nanofibers via anodizing in a concentrated pyrophosphoric acid under various conditions was investigated using electrochemical measurements and SEM/TEM observations. Pyrophosphoric acid anodizing at 293 K resulted in the formation of numerous anodic alumina nanofibers on an aluminum substrate through a thin barrier oxide and honeycomb oxide with narrow walls. However, long-term anodizing led to the chemical dissolution of the alumina nanofibers. The de...

  11. Novel tree-like WO3 nanoplatelets with very high surface area synthesized by anodization under controlled hydrodynamic conditions

    OpenAIRE

    Fernández Domene, Ramón Manuel; Sánchez Tovar, Rita; SEGURA SANCHIS, ELENA; Garcia-Anton, Jose

    2016-01-01

    In the present work, a new WO3 nanostructure has been obtained by anodization in a H2SO4/NaF electrolyte under controlled hydrodynamic conditions using a Rotating Disk Electrode (RDE) configuration. Anodized samples were analyzed by means of Field Emission Scanning Electronic Microscopy (FESEM), Confocal Raman Microscopy and photoelectrochemical measurements. The new nanostructure, which consists of nanoplatelets clusters growing in a tree-like manner, presents a very high surface area expose...

  12. Investigation of graphite composite anodes surfaces by atomic force microscopy and related techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hirasawa, Karen Akemi; Nishioka, Keiko; Sato, Tomohiro; Yamaguchi, Shoji; Mori, Shoichiro [Mitsubishi Chemical Corp., Tsukuba Research Center, Ibaraki (Japan)

    1997-11-01

    The surface of a synthetic graphite (KS-44) and polyvinylidene difluoride binder (PVDF) anode for lithium-ion secondary batteries is imaged using atomic force microscopy (AFM) and several related scanning probe microscope (SPM) instruments including: dynamic force microscopy (DFM), friction force microscopy (FFM), laterally-modulated friction force microscopy (LM-FFM), visco-elasticity atomic force microscopy (VE-AFM), and AFM/simultaneous current measurement mode (SCM). DFM is found to be an exceptional mode for topographic imaging while FFM results in the clearest contrast distinction between PVDF binder and KS-44 graphite regions. (orig.)

  13. Single chamber microbial fuel cell with spiral anode for dairy wastewater treatment.

    Science.gov (United States)

    Mardanpour, Mohammad Mahdi; Nasr Esfahany, Mohsen; Behzad, Tayebeh; Sedaqatvand, Ramin

    2012-01-01

    This study reports on the fabrication of a novel annular single chamber microbial fuel cell (ASCMFC) with spiral anode. The stainless steel mesh anode with graphite coating was used as anode. Dairy wastewater, containing complex organic matter, was used as substrate. ASCMFC had been operated for 450 h and results indicated a high open circuit voltage (about 810 mV) compared with previously published results. The maximum power density of 20.2 W/m(3) obtained in this study is significantly greater than the power densities reported in previous studies. Besides, a maximum coulombic efficiency of 26.87% with 91% COD removal was achieved. Good bacterial adhesion on the spiral anode is clearly shown in SEM micrographs. High power density and a successful performance in wastewater treatment in ASCMFC suggest it as a promising alternative to conventional MFCs for power generation and wastewater treatment. ASCMFC performance as a power generator was characterized based on polarization behavior and cell potentials. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Surface Coating Constraint Induced Self-Discharging of Silicon Nanoparticles as Anodes for Lithium Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Langli; Zhao, Peng; Yang, Hui; Liu, Borui; Zhang, Jiguang; Cui, Yi; Yu, Guihua; Zhang, Sulin; Wang, Chong M.

    2015-10-01

    One of the key challenges of Si-based anodes for lithium ion batteries is the large volume change upon lithiation and delithiation, which commonly leads to electrochemo-mechanical degradation and subsequent fast capacity fading. Recent studies have shown that applying nanometer-thick coating layers on Si nanoparticle (SiNPs) enhances cyclability and capacity retention. However, it is far from clear how the coating layer function from the point of view of both surface chemistry and electrochemo-mechanical effect. Herein, we use in situ transmission electron microscopy to investigate the lithiation/delithiation kinetics of SiNPs coated with a conductive polymer, polypyrrole (PPy). We discovered that this coating layer can lead to “self-delithiation” or “self-discharging” at different stages of lithiation. We rationalized that the self-discharging is driven by the internal compressive stress generated inside the lithiated SiNPs due to the constraint effect of the coating layer. We also noticed that the critical size of lithiation-induced fracture of SiNPs is increased from ~ 150 nm for bare SiNPs to ~ 380 nm for the PPy-coated SiNPs, showing a mechanically protective role of the coating layer. These observations demonstrate both beneficial and detrimental roles of the surface coatings, shedding light on rational design of surface coatings for silicon to retain high-power and high capacity as anode for lithium ion batteries.

  15. Novel Size and Surface Oxide Effects in Silicon Nanowires as Lithium Battery Anodes

    KAUST Repository

    McDowell, Matthew T.

    2011-09-14

    With its high specific capacity, silicon is a promising anode material for high-energy lithium-ion batteries, but volume expansion and fracture during lithium reaction have prevented implementation. Si nanostructures have shown resistance to fracture during cycling, but the critical effects of nanostructure size and native surface oxide on volume expansion and cycling performance are not understood. Here, we use an ex situ transmission electron microscopy technique to observe the same Si nanowires before and after lithiation and have discovered the impacts of size and surface oxide on volume expansion. For nanowires with native SiO2, the surface oxide can suppress the volume expansion during lithiation for nanowires with diameters <∼50 nm. Finite element modeling shows that the oxide layer can induce compressive hydrostatic stress that could act to limit the extent of lithiation. The understanding developed herein of how volume expansion and extent of lithiation can depend on nanomaterial structure is important for the improvement of Si-based anodes. © 2011 American Chemical Society.

  16. Laser Surface Melting of Stainless Steel Anodes for Reduced Hydrogen Outgassing (Postprint)

    Science.gov (United States)

    2016-12-29

    2,6]. Stable, long term HPS oper- ation is presently constrained by pulse shortening due to plasma formation in the anode-cathode gap region. Plasma is...wavelength of 1.064 lm, 6 D. Gortat et al. /Materials Letters 190 (2017) 5–8maximum output power of 20 W and nominal spot size of 39.4 lm. The treatment was...samples with the focused output of a 50 keV electron beam with a spot size of 1.6 mm in diameter (determined by measuring the size of a hole formed in a

  17. Treatment of Ni-EDTA containing wastewater by electrocoagulation using iron scraps packed-bed anode.

    Science.gov (United States)

    Ye, Xiaokun; Zhang, Junya; Zhang, Yan; Lv, Yuancai; Dou, Rongni; Wen, Shulong; Li, Lianghao; Chen, Yuancai; Hu, YongYou

    2016-12-01

    The unique electrocoagulator proposed in this study is highly efficient at removing Ni-EDTA, providing a potential remediation option for wastewater containing lower concentrations of Ni-EDTA (Ni ≤ 10 mg L -1 ). In the electrocoagulation (EC) system, cylindrical graphite was used as a cathode, and a packed-bed formed from iron scraps was used as an anode. The results showed that the removal of Ni-EDTA increased with the application of current and favoured acidic conditions. We also found that the iron scrap packed-bed anode was superior in its treatment ability and specific energy consumption (SECS) compared with the iron rod anode. In addition, the packed density and temperature had a large influence on the energy consumption (ECS). Over 94.3% of Ni and 95.8% of TOC were removed when conducting the EC treatment at an applied current of 0.5 A, initial pH of 3, air-purged rate 0.2 L min -1 , anode packed density of 400 kg m -3 temperature of 313 K and time of 30 min. SEM analysis of the iron scraps indicated that the specific area of the anode increased after the EC. The XRD analysis of flocs produced during EC revealed that hematite (α-Fe 2 O 3 ) and magnetite (Fe 3 O 4 ) were the main by-products under aerobic and anoxic conditions, respectively. A kinetic study demonstrated that the removal of Ni-EDTA followed a first-order model with the current parameters. Moreover, the removal efficiency of real wastewater was essentially consistent with that of synthetic wastewater. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Lanthanum Nitrate As Electrolyte Additive To Stabilize the Surface Morphology of Lithium Anode for Lithium-Sulfur Battery.

    Science.gov (United States)

    Liu, Sheng; Li, Guo-Ran; Gao, Xue-Ping

    2016-03-01

    Lithium-sulfur (Li-S) battery is regarded as one of the most promising candidates beyond conventional lithium ion batteries. However, the instability of the metallic lithium anode during lithium electrochemical dissolution/deposition is still a major barrier for the practical application of Li-S battery. In this work, lanthanum nitrate, as electrolyte additive, is introduced into Li-S battery to stabilize the surface of lithium anode. By introducing lanthanum nitrate into electrolyte, a composite passivation film of lanthanum/lithium sulfides can be formed on metallic lithium anode, which is beneficial to decrease the reducibility of metallic lithium and slow down the electrochemical dissolution/deposition reaction on lithium anode for stabilizing the surface morphology of metallic Li anode in lithium-sulfur battery. Meanwhile, the cycle stability of the fabricated Li-S cell is improved by introducing lanthanum nitrate into electrolyte. Apparently, lanthanum nitrate is an effective additive for the protection of lithium anode and the cycling stability of Li-S battery.

  19. Electrochemical treatment of pharmaceutical and industrial wastewater by anodic oxidation

    International Nuclear Information System (INIS)

    Menapace, H. M.; Fellerer, M.; Treschnitzer, M.

    2009-01-01

    In modern medicine pharmaceuticals play a decisive role: because of an increased life expectancy and intensive care medicine an increasing amount of pharmaceuticals is produced. thus these substances are consumed in a mass of tons per year in industrialized countries. Wastewater effluents from sewage treatment plants (STP) are important point sources for residues of pharmaceuticals and complexing agents in the aquatic environment. For this reason a research project, which started in December 2006, was established to eliminate pharmaceutical substances and complexing agents found in wastewater as micropollutants. (Author)

  20. Effect of ammonium-salt solutions on the surface properties of carbon fibers in electrochemical anodic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Qian Xin, E-mail: qx3023@nimte.ac.cn [National Engineering Laboratory of Carbon Fiber Preparation Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Wang Xuefei; Ouyang Qin; Chen Yousi; Yan Qing [National Engineering Laboratory of Carbon Fiber Preparation Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Longitudinal grooves on the fiber surface became more well-defined and much deeper after surface treatment. Black-Right-Pointing-Pointer The concentration of oxygen and nitrogen on the fiber surface increased after surface treatment. Black-Right-Pointing-Pointer The intensity of oxidative reaction varied with the change of ammonium-salt solutions. Black-Right-Pointing-Pointer The higher the concentration of OH{sup -} ions in the electrolytes, the violent the oxidative reaction happened. - Abstract: The surfaces of polyacrylonitrile-based carbon fibers were treated by an electrochemical anodic method. Three different kinds of ammonium-salt solutions namely NH{sub 4}HCO{sub 3}, (NH{sub 4}){sub 2}CO{sub 3} and (NH{sub 4}){sub 3}PO{sub 4} were respectively chosen as the electrolytes. The effect of these electrolytes on the surface structure was studied by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The results showed that longitudinal grooves on the fiber surface became more well-defined and much deeper after surface treatment, and the root mean square roughness (RMS) of carbon fiber surface increased from 4.6 nm for untreated fibers to 13.5 nm for treated fibers in (NH{sub 4}){sub 3}PO{sub 4} electrolytes. The concentration of oxygen and nitrogen atomic on the fiber surface increased after surface treatment. The tensile strength of oxidized fibers had an obvious decrease, whereas the interlaminar shear strength (ILSS) value of corresponding carbon fiber reinforced polymers (CFRPs) increased in a large extent. The intensity of oxidative reaction varied with the change of ammonium-salt solutions and electrochemical oxidation in (NH{sub 4}){sub 3}PO{sub 4} electrolyte was of the most violence. The corresponding mechanism was also discussed and the result showed that the higher the concentration of OH{sup -} ions in the electrolytes, the violent the oxidative

  1. Building 107 for surface treatment

    CERN Multimedia

    Brice, Maximilien

    2018-01-01

    A brand new state-of-the-art building hosting laboratories for the surface treatment of vacuum equipment and workshops for the manufacturing and treatment of printed circuit boards was completed in 2017.

  2. Surface patterned dielectrics by direct writing of anodic oxides using scanning droplet cell microscopy

    International Nuclear Information System (INIS)

    Siket, Christian M.; Mardare, Andrei Ionut; Kaltenbrunner, Martin; Bauer, Siegfried; Hassel, Achim Walter

    2013-01-01

    Highlights: • Scanning droplet cell microscopy was applied for local gate oxide writing. • Sharp lines are obtained at the highest writing speed of 1 mm min −1 . • 13.4 kC cm −3 was found as charge per volume for aluminium oxide. • High field constant of 24 nm V −1 and dielectric constant of 12 were determined for Al 2 O 3 by CV and EIS. -- Abstract: Scanning droplet cell microscopy was used for patterning of anodic oxide lines on the surface of Al thin films by direct writing. The structural modifications of the written oxide lines as a function of the writing speed were studied by analyzing the relative error of the line widths. Sharper lines were obtained for writing speeds faster than 1 mm min −1 . An increase in sharpness was observed for higher writing speeds. A theoretical model based on the Faraday law is proposed to explain the constant anodisation current measured during the writing process and yielded a charge per volume of 13.4 kC cm −3 for Al 2 O 3 . From calculated oxide film thicknesses the high field constant was found to be 24 nm V −1 . Electrochemical impedance spectroscopy revealed an increase of the electrical permittivity up to ε = 12 with the decrease of the writing speed of the oxide line. Writing of anodic oxide lines was proven to be an important step in preparing capacitors and gate dielectrics in plastic electronics

  3. Measurement of the surface charge accumulation using anodic aluminum oxide(AAO) structure in an inductively coupled plasma

    Science.gov (United States)

    Park, Ji-Hwan; Oh, Seung-Ju; Lee, Hyo-Chang; Kim, Yu-Sin; Kim, Young-Cheol; Kim, June Young; Ha, Chang-Seoung; Kwon, Soon-Ho; Lee, Jung-Joong; Chung, Chin-Wook

    2014-10-01

    As the critical dimension of the nano-device shrinks, an undesired etch profile occurs during plasma etch process. One of the reasons is the local electric field due to the surface charge accumulation. To demonstrate the surface charge accumulation, an anodic aluminum oxide (AAO) membrane which has high aspect ratio is used. The potential difference between top electrode and bottom electrode in an anodic aluminum oxide contact structure is measured during inductively coupled plasma exposure. The voltage difference is changed with external discharge conditions, such as gas pressure, input power, and gas species and the result is analyzed with the measured plasma parameters.

  4. Low-cost electrochemical treatment of indium tin oxide anodes for high-efficiency organic light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Hui Cheng, Chuan, E-mail: chengchuanhui@dlut.edu.cn; Shan Liang, Ze; Gang Wang, Li; Dong Gao, Guo; Zhou, Ting; Ming Bian, Ji; Min Luo, Ying [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Tong Du, Guo, E-mail: dugt@dlut.edu.cn [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China)

    2014-01-27

    We demonstrate a simple low-cost approach as an alternative to conventional O{sub 2} plasma treatment to modify the surface of indium tin oxide (ITO) anodes for use in organic light-emitting diodes. ITO is functionalized with F{sup −} ions by electrochemical treatment in dilute hydrofluoric acid. An electrode with a work function of 5.2 eV is achieved following fluorination. Using this electrode, a maximum external quantum efficiency of 26.0% (91 cd/A, 102 lm/W) is obtained, which is 12% higher than that of a device using the O{sub 2} plasma-treated ITO. Fluorination also increases the transparency in the near-infrared region.

  5. Effects of titanium surface anodization with CaP incorporation on human osteoblastic response

    Science.gov (United States)

    OLIVEIRA, Natássia Cristina Martins; MOURA, Camilla Christian Gomes; ZANETTA-BARBOSA, Darceny; MENDONÇA, Daniela Baccelli Silveira; MENDONÇA, Gustavo; DECHICHI, Paula

    2015-01-01

    In this study we investigated whether anodization with calcium phosphate (CaP) incorporation (Vulcano®) enhances growth factors secretion, osteoblast-specific gene expression, and cell viability, when compared to acid etched surfaces (Porous®) and machined surfaces (Screw®) after 3 and 7 days. Results showed significant cell viability for Porous and Vulcano at day 7, when compared with Screw (p=0.005). At the same time point, significant differences regarding runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP) and bone sialoprotein (BSP) expression were found for all surfaces (p0.05). Although no significant correlation was found for growth factors secretion and Runx2 expression, a significant positive correlation between this gene and ALP/BSP expression showed that their strong association is independent on the type of surface. The incorporation of CaP affected the biological parameters evaluated similar to surfaces just acid etched. The results presented here support the observations that roughness also may play an important role in determining cell response. PMID:23498218

  6. Fabrication of a novel aluminum surface covered by numerous high-aspect-ratio anodic alumina nanofibers

    Science.gov (United States)

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

    2015-11-01

    The formation behavior of anodic alumina nanofibers via anodizing in a concentrated pyrophosphoric acid under various conditions was investigated using electrochemical measurements and SEM/TEM observations. Pyrophosphoric acid anodizing at 293 K resulted in the formation of numerous anodic alumina nanofibers on an aluminum substrate through a thin barrier oxide and honeycomb oxide with narrow walls. However, long-term anodizing led to the chemical dissolution of the alumina nanofibers. The density of the anodic alumina nanofibers decreased as the applied voltage increased in the 10-75 V range. However, active electrochemical dissolution of the aluminum substrate occurred at a higher voltage of 90 V. Low temperature anodizing at 273 K resulted in the formation of long alumina nanofibers measuring several micrometers in length, even though a long processing time was required due to the low current density during the low temperature anodizing. In contrast, high temperature anodizing easily resulted in the formation and chemical dissolution of alumina nanofibers. The structural nanofeatures of the anodic alumina nanofibers were controlled by choosing of the appropriate electrochemical conditions, and numerous high-aspect-ratio alumina nanofibers (>100) can be successfully fabricated. The anodic alumina nanofibers consisted of a pure amorphous aluminum oxide without anions from the employed electrolyte.

  7. Fabrication and icing property of superhydrophilic and superhydrophobic aluminum surfaces derived from anodizing aluminum foil in a sodium chloride aqueous solution

    Science.gov (United States)

    Song, Meirong; Liu, Yuru; Cui, Shumin; Liu, Long; Yang, Min

    2013-10-01

    An aluminum foil with a rough surface was first prepared by anodic treatment in a neutral aqueous solution with the help of pitting corrosion of chlorides. First, the hydrophobic Al surface (contact angle around 79°) became superhydrophilic (contact angle smaller than 5°) after the anodizing process. Secondly, the superhydrophilic Al surface became superhydrophobic (contact angle larger than 150°) after being modified by oleic acid. Finally, the icing property of superhydrophilic, untreated, and superhydrophobic Al foils were investigated in a refrigerated cabinet at -12 °C. The mean total times to freeze a water droplet (6 μL) on the three foils were 17 s, 158 s and 1604 s, respectively. Thus, the superhydrophilic surface accelerates the icing process, while the superhydrophobic surface delays the process. The main reason for this transition might mainly result from the difference of the contact area of the water droplet with Al substrate: the increase in contact area with Al substrate will accelerate the heat conduct process, as well as the icing process; the decrease in contact area with Al substrate will delay the heat conduct process, as well as the icing process. Compared to the untreated Al foil, the contact area of the water droplet with the Al substrate was higher on superhydrophilic surface and smaller on the superhydrophobic surface, which led to the difference of the heat transfer time as well as the icing time.

  8. Surface-reconstructed Cu Electrode via a Facile Electrochemical Anodization-Reduction Process for Low Overpotential CO 2 reduction

    KAUST Repository

    Min, Shixiong; Yang, Xiulin; Lu, Ang-Yu; Tseng, Chien-Chih; Hedhili, Mohamed N.; Lai, Zhiping; Li, Lain-Jong; Huang, Kuo-Wei

    2017-01-01

    A high-surface-area Cu electrode, fabricated by a simple electrochemical anodization-reduction method, exhibits high activity and selectivity for CO2 reduction at low overpotential in 0.1 M KHCO3 solution. A faradaic efficiency of 37% for HCOOH

  9. Tailored lithium storage performance of graphene aerogel anodes with controlled surface defects for lithium-ion batteries

    International Nuclear Information System (INIS)

    Shan, Hui; Xiong, Dongbin; Li, Xifei; Sun, Yipeng; Yan, Bo; Li, Dejun; Lawes, Stephen; Cui, Yanhua; Sun, Xueliang

    2016-01-01

    Graphical abstract: - Highlights: • The graphene aerogel (GA) with controllable surface defects was synthesized. • The graphene aerogel anodes showed high specific capacity and excellent cyclability. • Surface defects on the GA significantly function for lithium storage. • This study can extend the application of the graphene anodes for LIBs. - Abstract: Three dimensional self-assembled graphene aerogel (GA) anode materials with some surface defects have been successfully generated through a facile hydrothermal procedure using graphene oxide as precursor. The morphologies and textural properties of as-obtained GA were investigated by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman and other spectroscopy techniques. The surface defects and electrical conductivities of GA can be controlled by adjusting the hydrothermal reaction time. The results indicate that GA with a reaction time of 6 h exhibits extremely high reversible capacity (1430 mAh g"−"1 at the current density of 100 mA g"−"1) and superior rate capability (587 mAh g"−"1 at 800 mA g"−"1) with excellent cycling stability (maintaining a reversible capacity of 960 mAh g"−"1 at 100 mA g"−"1 after 100 cycles). It is demonstrated that the 3D porous network with increased defect density, as well as the considerable electrical conductivity, results in the excellent electrochemical performance of the as-made GA anodes in lithium-ion batteries.

  10. A novel rotating electrochemically anodizing process to fabricate titanium oxide surface nanostructures enhancing the bioactivity of osteoblastic cells.

    Science.gov (United States)

    Chang, Chih-Hung; Lee, Hsin-Chun; Chen, Chia-Chun; Wu, Yi-Hau; Hsu, Yuan-Ming; Chang, Yin-Pen; Yang, Ta-I; Fang, Hsu-Wei

    2012-07-01

    Titanium oxide (TiO(2) ) surface layers with various surface nanostructures (nanotubes and nanowires) have been developed using an anodizing technique. The pore size and length of TiO(2) nanotubes can be tailored by changing the anodizing time and applied voltage. We developed a novel method to transform the upper part of the formed TiO(2) nanotubes into a nanowire-like structure by rotating the titanium anode during anodizing process. The transformation of nanotubes contributed to the preferential chemical dissolution of TiO(2) on the areas with intense interface tension stress. Furthermore, we further compared the effect of various TiO(2) surface nanostructures including flat, nanotubes, and nanowires on bioactive applications. The MG-63 osteoblastic cells cultured on the TiO(2) nanowires exhibited a polygonal shape with extending filopodia and showed highest levels of cell viability and alkaline phosphatase activity (ALP). The TiO(2) nanowire structure formed by our novel method can provide beneficial effects for MG-63 osteoblastic cells in attachment, proliferation, and secretion of ALP on the TiO(2) surface layer. Copyright © 2012 Wiley Periodicals, Inc.

  11. Enhancing pitting corrosion resistance of AlxCrFe1.5MnNi0.5 high-entropy alloys by anodic treatment in sulfuric acid

    International Nuclear Information System (INIS)

    Lee, C.P.; Chen, Y.Y.; Hsu, C.Y.; Yeh, J.W.; Shih, H.C.

    2008-01-01

    High-entropy alloys are a newly developed family of multi-component alloys that comprise various major alloying elements. Each element in the alloy system is present in between 5 and 35 at.%. The crystal structures and physical properties of high-entropy alloys differ completely from those of conventional alloys. The electrochemical impedance spectra (EIS) of the Al x CrFe 1.5 MnNi 0.5 (x = 0, 0.3, 0.5) alloys, obtained in 0.1 M HCl solution, clearly revealed that the corrosion resistance values were determined to increase from 21 to 34 Ωcm 2 as the aluminum content increased from 0 to 0.5 mol, and were markedly lower than that of 304 stainless steel (243 Ωcm 2 ). At passive potential, the corresponding current declined with the anodizing time accounting, causing passivity by the growth of the multi-component anodized film in H 2 SO 4 solution. X-ray photoelectron spectroscopy (XPS) analyses revealed that the surface of anodized Al 0.3 CrFe 1.5 MnNi 0.5 alloy formed aluminum and chromium oxide film which was the main passivating compound on the alloy. This anodic treatment increased the corrosion resistance in the EIS measurements of the CrFe 1.5 MnNi 0.5 and Al 0.3 CrFe 1.5 MnNi 0.5 alloys by two orders of magnitude. Accordingly, the anodic treatment of the Al x CrFe 1.5 MnNi 0.5 alloys optimized their surface structures and minimized their susceptibility to pitting corrosion

  12. Parabens abatement from surface waters by electrochemical advanced oxidation with boron doped diamond anodes.

    Science.gov (United States)

    Domínguez, Joaquín R; Muñoz-Peña, Maria J; González, Teresa; Palo, Patricia; Cuerda-Correa, Eduardo M

    2016-10-01

    The removal efficiency of four commonly-used parabens by electrochemical advanced oxidation with boron-doped diamond anodes in two different aqueous matrices, namely ultrapure water and surface water from the Guadiana River, has been analyzed. Response surface methodology and a factorial, composite, central, orthogonal, and rotatable (FCCOR) statistical design of experiments have been used to optimize the process. The experimental results clearly show that the initial concentration of pollutants is the factor that influences the removal efficiency in a more remarkable manner in both aqueous matrices. As a rule, as the initial concentration of parabens increases, the removal efficiency decreases. The current density also affects the removal efficiency in a statistically significant manner in both aqueous matrices. In the water river aqueous matrix, a noticeable synergistic effect on the removal efficiency has been observed, probably due to the presence of chloride ions that increase the conductivity of the solution and contribute to the generation of strong secondary oxidant species such as chlorine or HClO/ClO - . The use of a statistical design of experiments made it possible to determine the optimal conditions necessary to achieve total removal of the four parabens in ultrapure and river water aqueous matrices.

  13. Electrochemical treatment of wastewaters containing 4-chlororesorcinol using boron doped diamond anodes

    International Nuclear Information System (INIS)

    Nasr, B.; Abdelatif, G.

    2009-01-01

    The electrochemical oxidation of aqueous wastes polluted with 4-chlororesorcinol has been studied on boron-doped diamond electrodes on acidic medium. The voltammetric results showed that in the potential region where the supporting electrolyte is stable, reactions occur, resulting in the loss of activity due to electrode fouling. Galvanostatic electrolysis study showed that the oxidation of these wastes in single-compartment electrochemical flow cell with boron doped diamond anodes deal to the complete mineralization of the organics but is no indication of electrode fouling. Resorcinol, 1,2,4-trihydroxybenzene, benzoquinone, maleic, fumaric, and oxalic acids have been detected as soluble organics and chlorides (Cl - ) and hypochlorites (ClO - ) as mineral products during the electrolysis of 4-chlororesorcinol. The electrochemical oxidation of 4-chlororesorcinol consists of a sequence of steps: Release of Cl and/or hydroxylation of the aromatic ring; formation of quinonic compounds; oxidative opening of aromatic ring to form carboxylic acids; and oxidation of carboxylic acids to carbon dioxide. Both, direct oxidation at boron doped diamond surface and mediated oxidation by powerful oxidants electrogenerated from electrolyte oxidation at anode surface are involved in these stages. (author)

  14. Photo-induced electrochemical anodization of p-type silicon: achievement and demonstration of long term surface stability

    International Nuclear Information System (INIS)

    Dhanekar, Saakshi; Islam, S S; Harsh

    2012-01-01

    Surface stability is achieved and demonstrated by porous silicon (PS) fabricated using a wavelength-dependent photo-electrochemical (PEC) anodization technique. During anodization, the photon flux for all wavelengths was kept constant while only the effect of light wavelength on the surface morphology of PS was investigated. PS optical sensors were realized, characterized and tested using a photoluminescence (PL) quenching technique. An aliphatic chain of alcohols (methanol to n-octanol) was detected in the range of 10–200 ppm. Long term surface stability was observed from samples prepared under red (750–620 nm) and green illumination (570–495 nm), where the PL quenching cycles evoke the possibility of using PS for stable sensor device applications. This study provides a route for preparing highly sensitive organic vapour sensors with a precise selection of the fabrication parameters and demonstrating their prolonged performance. (paper)

  15. Treatment of carbon fiber brush anodes for improving power generation in air–cathode microbial fuel cells

    KAUST Repository

    Feng, Yujie

    2010-04-02

    Carbon brush electrodes have been used to provide high surface areas for bacterial growth and high power densities in microbial fuel cells (MFCs). A high-temperature ammonia gas treatment has been used to enhance power generation, but less energy-intensive methods are needed for treating these electrodes in practice. Three different treatment methods are examined here for enhancing power generation of carbon fiber brushes: acid soaking (CF-A), heating (CF-H), and a combination of both processes (CF-AH). The combined heat and acid treatment improve power production to 1370 mW m-2, which is 34% larger than the untreated control (CF-C, 1020 mW m-2). This power density is 25% higher than using only acid treatment (1100 mW m-2) and 7% higher than that using only heat treatment (1280 mW m-2). XPS analysis of the treated and untreated anode materials indicates that power increases are related to higher N1s/C1s ratios and a lower C-O composition. These findings demonstrate efficient and simple methods for improving power generation using graphite fiber brushes, and provide insight into reasons for improving performance that may help to further increase power through other graphite fiber modifications. © 2009 Elsevier B.V. All rights reserved.

  16. Graphite anode surface modification with controlled reduction of specific aryl diazonium salts for improved microbial fuel cells power output.

    Science.gov (United States)

    Picot, Matthieu; Lapinsonnière, Laure; Rothballer, Michael; Barrière, Frédéric

    2011-10-15

    Graphite electrodes were modified with reduction of aryl diazonium salts and implemented as anodes in microbial fuel cells. First, reduction of 4-aminophenyl diazonium is considered using increased coulombic charge density from 16.5 to 200 mC/cm(2). This procedure introduced aryl amine functionalities at the surface which are neutral at neutral pH. These electrodes were implemented as anodes in "H" type microbial fuel cells inoculated with waste water, acetate as the substrate and using ferricyanide reduction at the cathode and a 1000 Ω external resistance. When the microbial anode had developed, the performances of the microbial fuel cells were measured under acetate saturation conditions and compared with those of control microbial fuel cells having an unmodified graphite anode. We found that the maximum power density of microbial fuel cell first increased as a function of the extent of modification, reaching an optimum after which it decreased for higher degree of surface modification, becoming even less performing than the control microbial fuel cell. Then, the effect of the introduction of charged groups at the surface was investigated at a low degree of surface modification. It was found that negatively charged groups at the surface (carboxylate) decreased microbial fuel cell power output while the introduction of positively charged groups doubled the power output. Scanning electron microscopy revealed that the microbial anode modified with positively charged groups was covered by a dense and homogeneous biofilm. Fluorescence in situ hybridization analyses showed that this biofilm consisted to a large extent of bacteria from the known electroactive Geobacter genus. In summary, the extent of modification of the anode was found to be critical for the microbial fuel cell performance. The nature of the chemical group introduced at the electrode surface was also found to significantly affect the performance of the microbial fuel cells. The method used for

  17. In situ anodization of aluminum surfaces studied by x-ray reflectivity and electrochemical impedance spectroscopy

    International Nuclear Information System (INIS)

    Bertram, F.; Evertsson, J.; Messing, M. E.; Mikkelsen, A.; Lundgren, E.; Zhang, F.; Pan, J.; Carlà, F.; Nilsson, J.-O.

    2014-01-01

    We present results from the anodization of an aluminum single crystal [Al(111)] and an aluminum alloy [Al 6060] studied by in situ x-ray reflectivity, in situ electrochemical impedance spectroscopy and ex situ scanning electron microscopy. For both samples, a linear increase of oxide film thickness with increasing anodization voltage was found. However, the slope is much higher in the single crystal case, and the break-up of the oxide film grown on the alloy occurs at a lower anodization potential than on the single crystal. The reasons for these observations are discussed as are the measured differences observed for x-ray reflectivity and electrochemical impedance spectroscopy.

  18. Crystal structure and nanotopographical features on the surface of heat-treated and anodized porous titanium biomaterials produced using selective laser melting

    Energy Technology Data Exchange (ETDEWEB)

    Amin Yavari, S., E-mail: s.aminyavari@tudelft.nl [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands); FT Innovations BV, Braamsluiper 1, 5831 PW Boxmeer (Netherlands); Wauthle, R. [KU Leuven, Department of Mechanical Engineering, Section Production Engineering, Machine Design and Automation (PMA), Celestijnenlaan 300B, 3001 Leuven (Belgium); LayerWise NV, Kapeldreef 60, Leuven (Belgium); Böttger, A.J. [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands); Schrooten, J. [Department of Metallurgy and Materials Engineering, KU Leuven, Kasteelpark Arenberg 44 PB 2450, 3001 Heverlee (Belgium); Weinans, H. [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands); Department of Orthopedics and Department of Rheumatology, UMC Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands); Zadpoor, A.A. [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands)

    2014-01-30

    Porous titanium biomaterials manufactured using additive manufacturing techniques such as selective laser melting are considered promising materials for orthopedic applications where the biomaterial needs to mimic the properties of bone. Despite their appropriate mechanical properties and the ample pore space they provide for bone ingrowth and osseointegration, porous titanium structures have an intrinsically bioinert surface and need to be subjected to surface bio-functionalizing procedures to enhance their in vivo performance. In this study, we used a specific anodizing process to build a hierarchical oxide layer on the surface of porous titanium structures made by selective laser melting of Ti6Al4V ELI powder. The hierarchical structure included both nanotopographical features (nanotubes) and micro-features (micropits). After anodizing, the biomaterial was heat treated in Argon at different temperatures ranging between 400 and 600 °C for either 1 or 2 h to improve its bioactivity. The effects of applied heat treatment on the crystal structure of TiO{sub 2} nanotubes and the nanotopographical features of the surface were studied using scanning electron microscopy and X-ray diffraction. It was shown that the transition from the initial crystal structure, i.e. anatase, to rutile occurs between 500 and 600 °C and that after 2 h of heat treatment at 600 °C the crystal structure is predominantly rutile. The nanotopographical features of the surface were found to be largely unchanged for heat treatments carried out at 500 °C or below, whereas they were partially or largely disrupted after heat treatment at 600 °C. The possible implications of these findings for the bioactivity of porous titanium structures are discussed.

  19. Low-Surface-Area Hard Carbon Anode for Na-Ion Batteries via Graphene Oxide as a Dehydration Agent

    Energy Technology Data Exchange (ETDEWEB)

    Luo, W; Bommier, C; Jian, ZL; Li, X; Carter, R; Vail, S; Lu, YH; Lee, JJ; Ji, XL

    2015-02-04

    Na-ion batteries are emerging as one of the most promising energy storage technologies, particularly for grid-level applications. Among anode candidate materials, hard carbon is very attractive due to its high capacity and low cost. However, hard carbon anodes often suffer a low first-cycle Coulombic efficiency and fast capacity fading. In this study, we discover that doping graphene oxide into sucrose, the precursor for hard carbon, can effectively reduce the specific surface area of hard carbon to as low as 5.4 m(2)/g. We further reveal that such doping can effectively prevent foaming during caramelization of sucrose and extend the pyrolysis burnoff of sucrose caramel over a wider temperature range. The obtained low-surface-area hard carbon greatly improves the first-cycle Coulombic efficiency from 74% to 83% and delivers a very stable cyclic life with 95% of capacity retention after 200 cycles.

  20. Silver nanoparticles deposited on anodic aluminum oxide template using magnetron sputtering for surface-enhanced Raman scattering substrate

    Energy Technology Data Exchange (ETDEWEB)

    Wong-ek, Krongkamol [Nanoscience and Technology Program, Chulalongkorn University, Bangkok 10330 (Thailand); Eiamchai, Pitak; Horprathum, Mati; Patthanasettakul, Viyapol [National Electronics and Computer Technology Center, 112 Thailand Science Park, Phahonyothin Rd., Klong Luang, Pathumthani 12120 (Thailand); Limnonthakul, Puenisara [Department of Physics, Faculty of Science, King Mongkut' s University of Technology Thonburi, Bangkok 10140 (Thailand); Chindaudom, Pongpan [National Electronics and Computer Technology Center, 112 Thailand Science Park, Phahonyothin Rd., Klong Luang, Pathumthani 12120 (Thailand); Nuntawong, Noppadon, E-mail: noppadon.nuntawong@nectec.or.t [National Electronics and Computer Technology Center, 112 Thailand Science Park, Phahonyothin Rd., Klong Luang, Pathumthani 12120 (Thailand)

    2010-09-30

    Low-cost and highly sensitive surface-enhanced Raman scattering (SERS) substrates have been fabricated by a simple anodizing process and a magnetron sputtering deposition. The substrates, which consist of silver nanoparticles embedded on anodic aluminum oxide (AAO) templates, are investigated by a scanning electron microscope and a confocal Raman spectroscopy. The SERS activities are demonstrated by Raman scattering from adsorbed solutions of methylene blue and pyridine on the SERS substrate surface. The most optimized SERS substrate contains the silver nanoparticles, with a size distribution of 10-30 nm, deposited on the AAO template. From a calculation, the SERS enhancement factor is as high as 8.5 x 10{sup 7}, which suggests strong potentials for direct applications in the chemical detection and analyses.

  1. Surface modification of nanoporous anodic alumina photonic crystals for photocatalytic applications

    Science.gov (United States)

    Lim, Siew Yee; Law, Cheryl Suwen; Santos, Abel

    2018-01-01

    Herein, we report on the development of a rationally designed composite photocatalyst material by combining nanoporous anodic alumina-rugate filters (NAA-RFs) with photo-active layers of titanium dioxide (TiO2). NAA-RFs are synthesised by sinusoidal pulse anodisation and subsequently functionalised with TiO2 by sol-gel method to provide the photonic structures with photocatalytic properties. We demonstrate that the characteristic photonic stopband (PSB) of the surface-modified NAA-RFs can be precisely tuned across the UV-visible-NIR spectrum to enhance the photon-toelectron conversion of TiO2 by `slow photon effect'. We systematically investigate the effect of the anodisation parameters (i.e. anodisation period and pore widening time) on the position of the PSB of NAA-RFs as well as the photocatalytic performances displayed by these photonic crystal structures. When the edges of the PSB of surfacemodified NAA-RFs are positioned closely to the absorption peak of the model organic dye (i.e. methyl orange - MO), the photocatalytic performance of the system to degrade these molecules is enhanced under simulated solar light irradiation due to slow photon effect. Our investigation also reveals that the photocatalytic activity of surface-modified NAA-RFs is independent of slow photon effect and enhances with increasing period length (i.e. increasing anodisation period) of the photonic structures when there is no overlap between the PSB and the absorption peak of MO. This study therefore provides a rationale towards the photocatalytic enhancement of photonic crystals by a rational design of the PSB, creating new opportunities for the future development of high-performance photocatalysts.

  2. Enhanced osteoblast adhesion to drug-coated anodized nanotubular titanium surfaces

    Directory of Open Access Journals (Sweden)

    George E Aninwene II

    2008-06-01

    Full Text Available George E Aninwene II1, Chang Yao2, Thomas J Webster21Department of Biochemical Engineering, University of Maryland, Baltimore, MD; 2Division of Engineering, Brown University, Providence, RI, USAAbstract: Current orthopedic implants have functional lifetimes of only 10–15 years due to a variety of reasons including infection, extensive inflammation, and overall poor osseointegration (or a lack of prolonged bonding of the implant to juxtaposed bone. To improve properties of titanium for orthopedic applications, this study anodized and subsequently coated titanium with drugs known to reduce infection (penicillin/streptomycin and inflammation (dexamethasone using simple physical adsorption and the deposition of such drugs from simulated body fluid (SBF. Results showed improved drug elution from anodized nanotubular titanium when drugs were coated in the presence of SBF for up to 3 days. For the first time, results also showed that the simple physical adsorption of both penicillin/streptomycin and dexamethasone on anodized nanotubular titanium improved osteoblast numbers after 2 days of culture compared to uncoated unanodized titanium. In addition, results showed that depositing such drugs in SBF on anodized titanium was a more efficient method to promote osteoblast numbers compared to physical adsorption for up to 2 days of culture. In addition, osteoblast numbers increased on anodized titanium coated with drugs in SBF for up to 2 days of culture compared to unanodized titanium. In summary, compared to unanodized titanium, this preliminary study provided unexpected evidence of greater osteoblast numbers on anodized titanium coated with either penicillin/streptomycin or dexamethasone using simple physical adsorption or when coated with SBF; results which suggest the need for further research on anodized titanium orthopedic implants possessing drug-eluting nanotubes.Keywords: anodization, titanium, adhesion, simulated body fluid, nanotubes

  3. In vitro investigation of anodization and CaP deposited titanium surface using MG63 osteoblast-like cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J.M. [Department of Prosthodontics and Dental Research Institute, School of Dentistry, Seoul National University, 28 Yeongeon-dong, Jongno-gu, Seoul 110-749 (Korea, Republic of); Lee, J.I. [Department of Oral Pathology and Dental Research Institute, School of Dentistry, Seoul National University, Seoul (Korea, Republic of); Lim, Y.J., E-mail: limdds@snu.ac.kr [Department of Prosthodontics and Dental Research Institute, School of Dentistry, Seoul National University, 28 Yeongeon-dong, Jongno-gu, Seoul 110-749 (Korea, Republic of)

    2010-03-01

    The aim of the present study was to investigate surface characteristics in four different titanium surfaces (AN: anodized at 270 V; AN-CaP: anodic oxidation and CaP deposited; SLA: sandblasted and acid etched; MA: machined) and to evaluate biological behaviors such as cell adhesion, cell proliferation, cytoskeletal organization, and osteogenic protein expression of MG63 osteoblast-like cells at the early stage. Surface analysis was performed using scanning electron microscopy, thin-film X-ray diffractometry, and a confocal laser scanning microscope. In order to evaluate cellular responses, MG63 osteoblast-like cells were used. The cell viability was evaluated by MTT assay. Immunofluorescent analyses of actin, type I collagen, osteonectin and osteocalcin were performed. The anodized and CaP deposited specimen showed homogeneously distributed CaP particles around micropores and exhibited anatase type oxides, titanium, and HA crystalline structures. This experiment suggests that CaP particles on the anodic oxidation surface affect cellular attachment and spreading. When designing an in vitro biological study for CaP coated titanium, it must be taken into account that preincubation in medium prior to cell seeding and the cell culture medium may affect the CaP coatings. All these observations illustrate the importance of the experimental conditions and the physicochemical parameters of the CaP coating. It is considered that further evaluations such as long-term in vitro cellular assays and in vivo experiments should be necessary to figure out the effect of CaP deposition to biological responses.

  4. In vitro investigation of anodization and CaP deposited titanium surface using MG63 osteoblast-like cells

    International Nuclear Information System (INIS)

    Lee, J.M.; Lee, J.I.; Lim, Y.J.

    2010-01-01

    The aim of the present study was to investigate surface characteristics in four different titanium surfaces (AN: anodized at 270 V; AN-CaP: anodic oxidation and CaP deposited; SLA: sandblasted and acid etched; MA: machined) and to evaluate biological behaviors such as cell adhesion, cell proliferation, cytoskeletal organization, and osteogenic protein expression of MG63 osteoblast-like cells at the early stage. Surface analysis was performed using scanning electron microscopy, thin-film X-ray diffractometry, and a confocal laser scanning microscope. In order to evaluate cellular responses, MG63 osteoblast-like cells were used. The cell viability was evaluated by MTT assay. Immunofluorescent analyses of actin, type I collagen, osteonectin and osteocalcin were performed. The anodized and CaP deposited specimen showed homogeneously distributed CaP particles around micropores and exhibited anatase type oxides, titanium, and HA crystalline structures. This experiment suggests that CaP particles on the anodic oxidation surface affect cellular attachment and spreading. When designing an in vitro biological study for CaP coated titanium, it must be taken into account that preincubation in medium prior to cell seeding and the cell culture medium may affect the CaP coatings. All these observations illustrate the importance of the experimental conditions and the physicochemical parameters of the CaP coating. It is considered that further evaluations such as long-term in vitro cellular assays and in vivo experiments should be necessary to figure out the effect of CaP deposition to biological responses.

  5. Effects of Alclad Layer and Anodizing Time on Sulfuric Acid Anodizing and Film Properties of 2E12 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    CHEN Gao-hong

    2017-07-01

    Full Text Available Alclad and unclad 2E12 aerospace aluminum alloy were treated by sulfuric acid anodic oxidation. The effects of alclad layer and anodizing time on the anodization behaviour and corrosion resistance of anodic oxide layer on 2E12 aluminum alloy were studied. Surface and cross-section morphology of anodic oxide films were observed by scanning electron microscopy. The electrochemical properties of anodic oxide films were analyzed by potentiodynamic polarization curve and electrochemical impedance spectroscopy. The results show that the protective anodic oxide layers are formed on alclad and unclad 2E12 aluminum alloy. The film thickness increases with anodizing time extending. The copper rich second phase particles lead to more cavity defects and even micro cracks on anodic oxide films of unclad 2E12 aluminum alloy. The anodic oxide films on alclad 2E12 aluminum alloy are thicker and have fewer cavity defects, resulting in better corrosion resistance. The films obtained after 30min and 45min anodic oxidation treatment exhibit lower corrosion current and higher impedance of the porous layer than other anodizing time.

  6. Surface study of nano-template anodic porous alumina pre-irradiated by ArF laser

    International Nuclear Information System (INIS)

    Jaleh, B.; Saramad, S.; Farshchi-Tabrizi, M.

    2009-01-01

    Nano-porous alumina membranes have widely used as matrix for the fabrication of nanomaterials for many applications including quantum-dot arrays, magnetic storage devices and composites for catalysis, due to their remarkable hardness, thermal and anti corrupted stability, uniform pore size and high pore density. In this experiment three sets of aluminum samples were chosen for fabrication nano-porous anodic alumina. One set has select for laser cleaning before chemical treatment and the two others with and without chemical treatment without laser irradiation. Anodic aluminum oxide (AAO) films were characterized with Scanning Electron Microscope (SEM) and Atomic Force Microscope (AFM) micrograph and the SEM results were analyzed by Linear-Angular Fast Fourier Transform (LA-FFT) technique to investigate the arrangement and ordering of pores. According to these results the laser irradiated sample has much better regularity in comparison with the usual one.

  7. Coupling biofiltration process and electrocoagulation using magnesium-based anode for the treatment of landfill leachate.

    Science.gov (United States)

    Oumar, Dia; Patrick, Drogui; Gerardo, Buelna; Rino, Dubé; Ihsen, Ben Salah

    2016-10-01

    In this research paper, a combination of biofiltration (BF) and electrocoagulation (EC) processes was used for the treatment of sanitary landfill leachate. Landfill leachate is often characterized by the presence of refractory organic compounds (BOD/COD < 0.13). BF process was used as secondary treatment to remove effectively ammonia nitrogen (N-NH4 removal of 94%), BOD (94% removed), turbidity (95% removed) and phosphorus (more than 98% removed). Subsequently, EC process using magnesium-based anode was used as tertiary treatment. The best performances of COD and color removal from landfill leachate were obtained by applying a current density of 10 mA/cm(2) through 30 min of treatment. The COD removal reached 53%, whereas 85% of color removal was recorded. It has been proved that the alkalinity had a negative effect on COD removal during EC treatment. COD removal efficiencies of 52%, 41% and 27% were recorded in the presence of 1.0, 2.0 and 3.0 g/L of sodium bicarbonate (NaHCO3), respectively. Hydroxide ions produced at the cathode electrode reacted with the bicarbonate ions to form carbonates. The presence of bicarbonates in solution hampered the increase in pH, so that the precipitation of magnesium hydroxides could not take place to effectively remove organic pollutants. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Facile fabrication of superhydrophobic surfaces with low roughness on Ti–6Al–4V substrates via anodization

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Yuze; Sun, Yuwen, E-mail: ywsun@dlut.edu.cn; Guo, Dongming

    2014-09-30

    Highlights: • A facile and efficient method for fabricating low-roughness superhydrophobic titanium alloy surfaces is successfully developed. • Formation mechanism of micro-scale pore structures built by a novel anodic oxidation is carefully analyzed. • The prepared superhydrophobic surface possesses good durability and abrasion resistance. - Abstract: The combination of suitable micro-scale structures and low surface energy modification plays a vital role in fabricating superhydrophobic surfaces on hydrophilic metal substrates. This work proposes a simple, facile and efficient method of fabricating superhydrophobic titanium alloy surfaces with low surface roughness. Complex micro-pore structures are generated on titanium alloy surfaces by anodic oxidation in the NaOH and H{sub 2}O{sub 2} mixed solution. Fluoroalkylsilane (FAS) is used to reduce the surface energy of the electrochemically oxidized surface. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Zygogpi-xp6 (ZYGO) and contact angle measurements are performed to determine the morphological features, chemical composition, surface roughness and wettability. The formation mechanism of micro-scale rough structures, wettability of the superhydrophobic surfaces and the relationship between reaction time with wettability and roughness of the superhydrophobic surfaces are also analyzed in detail. The as-prepared titanium alloy surfaces not only show low roughness Ra = 0.669 μm and good superhydrophobicity with a water contact angle of 158.5° ± 1.9° as well as a water tilting angle of 5.3° ± 1.1°, but also possess good long-term stability and abrasion resistance.

  9. Experimental determination of effective surface area and conductivities in the porous anode of molten carbonate fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, M.; Boden, A.; Sparr, M.; Lindbergh, G. [Central Research Institute for Electric Power Industry, Kanagawa (Japan)

    2006-07-14

    Stationary polarization curves and electrochemical impedance spectroscopy of a porous nickel anode in a molten carbonate fuel cell were obtained in order to determine the active surface area and conductivities with varying degree of electrolyte filling for two anode feed-gas compositions, one simulating operation with steam reformed natural gas and the other one gasified coal. The active surface area for coal gas is reduced by around 70-80% compared to the standard gas composition in the case of Li/Na carbonate. Moreover, an optimal degree of electrolyte filling was shifted toward higher filling degree in the case of operation with coal gas. In order to evaluate the experimental data a one-dimensional model was used. The reaction rate at the matrix/electrode interface is about five times higher than the average reaction rate in the whole electrode in case of 10% electrolyte filling. This result suggests that the lower limit of the filling degree of the anode should be around 15% in order to avoid non-uniform distribution of the reaction in the electrode. Therefore, in the case of applying Li/Na carbonate in the MCFC, an electrolyte distribution model taking into account the wetting properties of the electrode is required in order to set an optimal electrolyte filling degree in the electrode.

  10. Surface-reconstructed Cu Electrode via a Facile Electrochemical Anodization-Reduction Process for Low Overpotential CO 2 reduction

    KAUST Repository

    Min, Shixiong

    2017-03-21

    A high-surface-area Cu electrode, fabricated by a simple electrochemical anodization-reduction method, exhibits high activity and selectivity for CO2 reduction at low overpotential in 0.1 M KHCO3 solution. A faradaic efficiency of 37% for HCOOH and 27% for CO production was achieved with the current density of 1.5 mA cm-2 at −0.64 V vs. RHE, much higher than that of polycrystalline Cu. The enhanced catalytic performance is a result of the formation of the high electrochemical active surface area and high density of preferred low-index facets.

  11. Effect of anodization on the surface characteristics and electrochemical behaviour of zirconium in artificial saliva.

    Science.gov (United States)

    Romonti, Daniela E; Gomez Sanchez, Andrea V; Milošev, Ingrid; Demetrescu, Ioana; Ceré, Silvia

    2016-05-01

    The paper is focused on elaboration of ZrO2 films on pure zirconium via anodizing in phosphoric acid with and without fluoride at constant potentials of 30 V and 60 V. The structure and composition of the films were investigated using scanning electronic microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The composition of the oxides formed at both potentials can be identified as monoclinic ZrO2. In addition to Zr and O, the layers formed in phosphoric acid contain phosphorus originating from the phosphoric acid. When the phosphoric acid solution contains NaF, fluorine is also incorporated into the oxide layer. The oxides formed at a higher voltage have greater roughness than those formed at 30 V. Anodized samples exhibit smaller current densities during anodic polarization compared to the as-received zirconium covered with native oxide. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Effect of pentacene/Ag anode buffer and UV-ozone treatment on durability of small-molecule organic solar cells

    International Nuclear Information System (INIS)

    Inagaki, S; Sueoka, S; Harafuji, K

    2017-01-01

    Three surface modifications of indium tin oxide (ITO) are experimentally investigated to improve the performance of small-molecule organic solar cells (OSCs) with an ITO/anode buffer layer (ABL)/copper phthalocyanine (CuPc)/fullerene/bathocuproine/Ag structure. An ultrathin Ag ABL and ultraviolet (UV)-ozone treatment of ITO independently improve the durability of OSCs against illumination stress. The thin pentacene ABL provides good ohmic contact between the ITO and the CuPc layer, thereby producing a large short-circuit current. The combined use of the abovementioned three modifications collectively achieves both better initial performance and durability against illumination stress. (paper)

  13. Effect of pentacene/Ag anode buffer and UV-ozone treatment on durability of small-molecule organic solar cells

    Science.gov (United States)

    Inagaki, S.; Sueoka, S.; Harafuji, K.

    2017-06-01

    Three surface modifications of indium tin oxide (ITO) are experimentally investigated to improve the performance of small-molecule organic solar cells (OSCs) with an ITO/anode buffer layer (ABL)/copper phthalocyanine (CuPc)/fullerene/bathocuproine/Ag structure. An ultrathin Ag ABL and ultraviolet (UV)-ozone treatment of ITO independently improve the durability of OSCs against illumination stress. The thin pentacene ABL provides good ohmic contact between the ITO and the CuPc layer, thereby producing a large short-circuit current. The combined use of the abovementioned three modifications collectively achieves both better initial performance and durability against illumination stress.

  14. Effects of thermal treatment on the anodic growth of tungsten oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Chai, Y., E-mail: yqchai85@gmail.com; Tam, C.W.; Beh, K.P.; Yam, F.K.; Hassan, Z.

    2015-08-03

    This work reports the investigation of the effects of thermal treatment on anodic growth tungsten oxide (WO{sub 3}). The increase of the thermal treatment temperature above 400 °C significantly influences WO{sub 3} film where high porosity structure reduces to more compact film. As-grown film is amorphous, which transforms to monoclinic/orthorhombic phase upon annealing at 300–600 °C. With the reducing of porous structure, preferential growth of (002) plane shifts to (020) plane at 600 °C with more than twentyfold increase of peak's intensity compared to the film annealed at 500 °C. Films annealed at low thermal treatment show better ion intercalation and reversibility during electrochemical measurements; however, it has larger optical band gap. Photoelectrochemical measurement reveals that film annealed at 400 °C exhibits the best photocatalytic performance among the films annealed at 300–600 °C. - Highlights: • Porosity of the WO{sub 3} reduces as annealing temperature increases above 400 °C. • As-grown film is amorphous which transforms to monoclinic/orthorhombic upon annealing. • As-grown film shows better ion intercalation in electrochemical process. • Optical band gap of WO{sub 3} reduces as the annealing temperature increases. • Film annealed at 400 °C exhibits best photocatalytic performance.

  15. Engineering of Nanoscale Antifouling and Hydrophobic Surfaces on Naval Structural Steel HY-80 by Anodizing

    Science.gov (United States)

    2015-06-01

    stainless steel by anodization. The oxide structures produced under these conditions granted the material significant visible light photo catalytic...metallurgically classified as quenched and tempered martensitic steels . They have a martensitic microstructure resulting from the 9 combination of...producing a martensitic structure is carbon. The as-quenched steel manifests high strength and hardness but also is brittle and susceptible to hydrogen

  16. Comparison of modelling and experimental results of anode surface melting by femtosecond laser-stimulated electrical discharges in small gaps

    International Nuclear Information System (INIS)

    Chen Jian; He Lingna; Farson, Dave F; Rokhlin, Stanislav I

    2011-01-01

    Experiments and particle-in-cell simulations of femtosecond laser-stimulated electrical discharges in submicrometre gaps between scanning tunnelling microscope tip cathodes and gold film anodes are described. In experiments at applied potentials of 35 V and less, discharges were detected either as self-terminating low-current pulses with durations less than 10 ns and magnitudes less than 200 mA or as higher-current, longer-duration current waveforms. The probability of occurrence of low-current pulses increased as applied potential was decreased, being certain at low potentials of 20-25 V. Low-current pulse waveforms and surface melting of gold anodes predicted by the simulations were compared with experiments. Laser stimulation was modelled by introducing partially ionized electrode materials into the simulation domain at a controlled rate. Simulation results showed that the duration of low-current pulses was influenced by the time over which material was added to the gap region, establishing the importance of electrode vaporization on discharge duration. Subsequently, partially ionized electrode materials were preloaded into the gap in controlled amounts in subsequent simulations. Peak currents predicted by these simulations were nearly equal to the low-current pulse measurements but simulated pulse durations were shorter than experiments. Thus, the time axis of simulation current profiles was normalized for equality of charge transfer with experiments. Anode temperatures and melt diameters calculated from normalized simulated heat input profiles were well matched to experimental measurements.

  17. 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.

  18. Assessment of Surface Area Characteristics of Dental Implants with Gradual Bioactive Surface Treatment

    Science.gov (United States)

    Czan, Andrej; Babík, Ondrej; Miklos, Matej; Záušková, Lucia; Mezencevová, Viktória

    2017-10-01

    Since most of the implant surface is in direct contact with bone tissue, shape and integrity of said surface has great influence on successful osseointegration. Among other characteristics that predetermine titanium of different grades of pureness as ideal biomaterial, titanium shows high mechanical strength making precise miniature machining increasingly difficult. Current titanium-based implants are often anodized due to colour coding. This anodized layer has important functional properties for right usage and also bio-compatibility of dental implants. Physical method of anodizing and usage of anodizing mediums has a significant influence on the surface quality and itself functionality. However, basic requirement of the dental implant with satisfactory properties is quality of machined surface before anodizing. Roughness, for example, is factor affecting of time length of anodizing operation and so whole productivity. The paper is focused on monitoring of surface and area characteristics, such as roughness or surface integrity after different cutting conditions of miniature machining of dental implants and their impact on suitability for creation of satisfactory anodized layer with the correct biocompatible functional properties.

  19. Evaluation of the properties of anodized aluminum 6061 subjected to thermal cycling treatment using electrochemical impedance spectroscopy (EIS)

    Energy Technology Data Exchange (ETDEWEB)

    Huang Yuelong [Corrosion and Environmental Effects Laboratory (CEEL), Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-0241 (United States); Shih Hong [Lam Research Corporation, 4400 Cushing Parkway, Fremont, CA 94538 (United States)], E-mail: hong.shih@lamrc.com; Daugherty, John [Lam Research Corporation, 4400 Cushing Parkway, Fremont, CA 94538 (United States); Mansfeld, Florian [Corrosion and Environmental Effects Laboratory (CEEL), Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-0241 (United States)], E-mail: mansfeld@usc.edu

    2009-10-15

    The corrosion resistance of anodized Al 6061 produced by two different anodizing and sealing processes was evaluated for 30 days during exposure to 3.5 wt% NaCl using EIS. Thermal cycling treatments at 120, 160 and 200 deg. C have been applied for the two types of samples. The degradation of the properties of the anodized layers has been determined by thorough analysis of the EIS data for control samples and samples that had undergone thermal cycling. Scanning electron microscopy has been used to evaluate the damage to the anodized aluminum layers due to thermal cycling. It was found that the thermal treatment produced considerable damage of both the porous layer and the barrier layer. The EIS data suggest that some cracks extended into the bare metal. The damage of the oxide layers increased with increasing thermal cycling temperature for both types of samples. Self-sealing of the porous layer and the barrier layer occurred during immersion in NaCl.

  20. Improved biological performance of low modulus Ti-24Nb-4Zr-7.9Sn implants due to surface modification by anodic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Y. [School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Gao, B., E-mail: gaobo_fmmu@163.com [School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Wang, R. [Fengtai Health Center of Navy Outpatient Department, Beijing 100071 (China); Wu, J.; Zhang, L.J. [School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Hao, Y.L.; Tao, X.J. [Institute of Metal Research Chinese Academy of Sciences, Shenyang 110016 (China)

    2009-02-15

    Dental implants are usually made from commercially pure titanium or titanium alloys. The purpose of this study was to evaluate the influence of surface treatment to low modulus Ti-24Nb-4Zr-7.9Sn (TNZS) on cell and bone responses. The TNZS alloy samples were modified using anodic oxidation (AD). Surface oxide properties were characterized by using various surface analytic techniques, involving scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS), X-ray diffractometry (XRD) and surface profilometer. During the AD treatment, porous titanium oxide layer was formed and Ca ions were incorporated into the oxide layer. The viability and morphology of osteoblasts on Ca-incorporated TNZS were studied. The bone responses of Ca-incorporated TNZS were evaluated by pull-out tests and morphological analysis after implantation in rabbit tibiae. The non-treated Ti and TNZS samples were used as the control. Significant increases in cell viability and pull-out forces (p < 0.05) were observed for Ca-incorporated TNZS implants compared with those for the control groups. Porous structures supplied positive guidance cues for osteoblasts to attach. The enhanced cell and bone responses to Ca-incorporated TNZS implants could be explained by the surface chemistry and microtopography.

  1. Hydrogen effects in anodic grinding of WC-Co sintered alloy

    International Nuclear Information System (INIS)

    Lunarska, E.; Zaborski, St.

    2001-01-01

    The effects of anodic polarization applied in grinding of sintered WC C o alloy on properties of surface layer, quality of ground surface and efficiency of the treatment were studied. The nonmonotonical change of the surface roughness, the energy consumption and the wear of tool was stated at increasing anodic polarization. The optimum values of above parameters were achieved at application of anodic polarization at which the Co selective dissolution and hydrogen ingress into the ground metal. affecting the internal friction spectra were stated. The assistance of hydrogen induced deterioration and Co selective dissolution in the surface layer in the anodic grinding of WC-Co alloy has been discussed. (author)

  2. Core-shell Si/Cu nanocomposites synthesized by self-limiting surface reaction as anodes for lithium ion batteries

    Science.gov (United States)

    Xu, Kaiqi; Zhang, Zhizhen; Su, Wei; Huang, Xuejie

    Core-shell Si/Cu nanocomposites were synthesized via a flexible self-limiting surface reaction without extra reductant for the first time. The nano Si was uniformly coated with Cu nanoparticles with a diameter of 5-10nm, which can enhance the electronic conductivity of the nanocomposites and buffer the huge volume change during charge/discharge owing to its high ductility. Benefited from the unique structure, the Si/Cu nanocomposites exhibited a good electrochemical performance as anodes for lithium ion batteries, which exhibited a capacity retention of 656mAh/g after 50 cycles and a coulombic efficiency of more than 99%.

  3. Enhancement of the Electrocatalytic Activity of Gold Nanoparticles via Anodic Treatment and the Decrease of the Enhanced Activity with Aging

    International Nuclear Information System (INIS)

    Jo, Kyung Min; Kang, Hyun Ju; Yang, Hae Sik

    2011-01-01

    We have recently shown that the electrocatalytic activity of Au nanoparticles (AuNPs) can be enhanced via NaBH 4 treatment and cathodic treatment and that the enhanced activity slowly decreases with aging. We have also demonstrated that the electrocatalytic activity of the AuNPs freshly prepared by electrochemical or chemical reduction slowly decreases with aging in both air and solution. Likewise, the electrocatalytic activity of anodically treated Au electrodes or AuNPs might change with aging. Herein, we report that the electrocatalytic activity of long-aged AuNPs can be enhanced via anodic treatment and that the enhanced electrocatalytic activity decreases with aging in air. The change in the electrocatalytic activity of AuNPs was evaluated by comparing cyclic voltammograms for the electrooxi-dation of hydrogen peroxide (H 2 O 2 ) and formic acid

  4. Surface chemistry and morphology of the solid electrolyte interphase on silicon nanowire lithium-ion battery anodes

    KAUST Repository

    Chan, Candace K.

    2009-04-01

    Silicon nanowires (SiNWs) have the potential to perform as anodes for lithium-ion batteries with a much higher energy density than graphite. However, there has been little work in understanding the surface chemistry of the solid electrolyte interphase (SEI) formed on silicon due to the reduction of the electrolyte. Given that a good, passivating SEI layer plays such a crucial role in graphite anodes, we have characterized the surface composition and morphology of the SEI formed on the SiNWs using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). We have found that the SEI is composed of reduction products similar to that found on graphite electrodes, with Li2CO3 as an important component. Combined with electrochemical impedance spectroscopy, the results were used to determine the optimal cycling parameters for good cycling. The role of the native SiO2 as well as the effect of the surface area of the SiNWs on reactivity with the electrolyte were also addressed. © 2009 Elsevier B.V. All rights reserved.

  5. Anodized aluminum on LDEF

    Science.gov (United States)

    Golden, Johnny L.

    1993-01-01

    A compilation of reported analyses and results obtained for anodized aluminum flown on the Long Duration Exposure Facility (LDEF) was prepared. Chromic acid, sulfuric acid, and dyed sulfuric acid anodized surfaces were exposed to the space environment. The vast majority of the anodized surface on LDEF was chromic acid anodize because of its selection as a thermal control coating for use on the spacecraft primary structure, trays, tray clamps, and space end thermal covers. Reports indicate that the chromic acid anodize was stable in solar absorptance and thermal emittance, but that contamination effects caused increases in absorptance on surfaces exposed to low atomic oxygen fluences. There were some discrepancies, however, in that some chromic acid anodized specimens exhibited significant increases in absorptance. Sulfuric acid anodized surfaces also appeared stable, although very little surface area was available for evaluation. One type of dyed sulfuric acid anodize was assessed as an optical baffle coating and was observed to have improved infrared absorptance characteristics with exposure on LDEF.

  6. The fabrication of Ag nanoflake arrays via self-assembly on the surface of an anodic aluminum oxide template

    International Nuclear Information System (INIS)

    Li Xueming; Dong Kun; Tang Libin; Wu, Yongjun; Yang Peizhi; Zhang Pengxiang

    2010-01-01

    Vertical-aligned Ag nanoflake arrays are fabricated on the surface of an anodic aluminum oxide (AAO) template under a hydrothermal condition for the first time. The porous surface of AAO templates and the precursor solution may play key roles in the process of fabricating Ag nanoflakes. The rim of pores can provide many active sites for nucleation and growth, and then nanoflake arrays gradually form through self-assembly of Ag on the surface of AAO membranes. The product is characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and a growth mechanism of nanoflake is deduced. This work demonstrates that it is possible to make ordered nanoarrays without dissolving templates using the hydrothermal method, and this interesting Ag nanoflake arrays may provide a wider range of nanoscale applications.

  7. The fabrication of Ag nanoflake arrays via self-assembly on the surface of an anodic aluminum oxide template

    Science.gov (United States)

    Li, Xueming; Dong, Kun; Tang, Libin; Wu, Yongjun; Yang, Peizhi; Zhang, Pengxiang

    2010-02-01

    Vertical-aligned Ag nanoflake arrays are fabricated on the surface of an anodic aluminum oxide (AAO) template under a hydrothermal condition for the first time. The porous surface of AAO templates and the precursor solution may play key roles in the process of fabricating Ag nanoflakes. The rim of pores can provide many active sites for nucleation and growth, and then nanoflake arrays gradually form through self-assembly of Ag on the surface of AAO membranes. The product is characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and a growth mechanism of nanoflake is deduced. This work demonstrates that it is possible to make ordered nanoarrays without dissolving templates using the hydrothermal method, and this interesting Ag nanoflake arrays may provide a wider range of nanoscale applications.

  8. Modification of TiO{sub 2} powder via atmospheric dielectric barrier discharge treatment for high performance lithium-ion battery anodes

    Energy Technology Data Exchange (ETDEWEB)

    Chuang, Shang-I; Yang, Hao; Chen, Hsien-Wei; Duh, Jenq-Gong, E-mail: jgd@mx.nthu.edu.tw

    2015-12-01

    The main objective of this study is to improve the electrochemical performances of TiO{sub 2} Li-ion anode material by introducing plasma treatment on TiO{sub 2} powder. A specially designed atmospheric dielectric barrier discharge plasma generator feasible to modify powders is proposed. The rate capacity of 20 min plasma-treated TiO{sub 2} anode revealed nearly 20% increment as compared to that of pristine TiO{sub 2} at the rates of 0.5, 1, 2, 5, 10 C. As-treated TiO{sub 2} was first analyzed by the X-ray diffractometer and high resolution transmission electron microscope confirmed that there was no noticeable surface morphology and microstructure change from plasma treatment. In addition, plasma-treated TiO{sub 2} was reduced with increasing treatment duration. Significant amount of excited argon (Ar{sup ∗}) and excitation of a nitrogen second positive system (N{sub 2}{sup ∗}) were discovered using optical emission spectroscopy (OES). It was believed that Ar{sup ∗} and N{sub 2}{sup ∗} contributed to TiO{sub 2} surface reduction as companied by formation of oxygen vacancy. A higher amount of oxygen vacancy increases the chance of allowing excited nitrogen to dope onto surface of TiO{sub 2} particle. Electrochemical properties of TiO{sub 2} were raised due to the production of oxygen vacancy and nitrogen doping. These findings enhance the understanding of the atmospheric plasma treatment on the potential application of TiO{sub 2} anode material in Li-ion battery. - Highlights: • A plasma generator was developed and proposed for modifying TiO{sub 2} powder in enhancing its electrochemical property. • The plasma treated TiO{sub 2} revealed 20% increment in capacity under different C-rates. • Plasma diagnosis was performed providing an insight of how plasma treatment is effective in TiO{sub 2} surface modification.

  9. Electrocoagulation using a rotated anode: A novel reactor design for textile wastewater treatment.

    Science.gov (United States)

    Naje, Ahmed Samir; Chelliapan, Shreeshivadasan; Zakaria, Zuriati; Abbas, Saad A

    2016-07-01

    This paper investigates the optimum operational conditions of a novel rotated bed electrocoagulation (EC) reactor for the treatment of textile wastewater. The effect of various operational parameters such as rotational speed, current density (CD), operational time (RT), pH, temperature, and inter-electrode distance (IED) on the pollutant removal efficiency were examined. In addition, the consumption of aluminum (Al) and electrical energy, as well as operating costs at optimum conditions were also calculated. The results indicated that the optimum conditions for the treatment of textile wastewater were achieved at CD = 4 mA/cm(2), RT = 10 min, rotational speed = 150 rpm, pH = 4.57, temperature = 25 °C, and IED = 1 cm. The electrode consumption, energy consumption, and operating costs were 0.038 kg/m(3), 4.66 kWh/m(3) and 0.44 US$/m(3), respectively. The removal efficiencies of chemical oxygen demand (COD), biological oxygen demand (BOD), total suspended solid (TSS), turbidity and color were 97.10%, 95.55%, 98%, 96% and 98.50%, respectively, at the first 10 min of reaction time, while the phenol compound of the wastewater was almost entirely removed (99.99%). The experimental results confirm that the new reactor design with rotated anode impellers and cathode rings provided high treatment efficiency at a reduced reaction time and with lower energy consumption. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Surface engineering and heat treatment

    International Nuclear Information System (INIS)

    Morton, P.H.

    1991-01-01

    This book is the proceedings of a Conference organised jointly by The Institute of Metals and The Centre for Exploitation of Science and Technology (CEST). It sets out to review this role and point the way to the future by collecting together a series of invited papers written by noted authorities in their fields. The opening review by CEST highlights the economic and industrial importance of Surface Engineering and is followed by a group of four articles devoted to specific branches of industry. Several technical papers then describe various aspects of the development of heat treatment over the last twenty-five years. These are followed by papers describing advances made possible by new technologies such as plasma, laser and ion beam. A separate abstract has been prepared for a paper on materials aspects of ion beam technology. (author)

  11. Environmental performance assessment of a company of aluminum surface treatment

    Directory of Open Access Journals (Sweden)

    Susan Catieri Ramalho

    2013-08-01

    Full Text Available The purpose of this article was to evaluate the environmental performance of a medium-sized company that provides services for surface treatment of aluminum. The treatment is known as anodizing. The research method was qualitative numerical modeling. The environmental performance of the company was organized into five constructs: atmosphere, wastewater, energy and natural resources, solid waste, and legislation and management. Nineteen indicators were chosen to explain the five constructs. Ten employees of the company prioritized the constructs and evaluated the situation of the indicators by means of a scale of assessment. By means of a mathematical model, the general performance of the environmental operation was calculated at 74.5% of the maximum possible. The indicators that most contributed to the performance not to reach 100% were consumption of electricity and water consumption. The construct of worse performance was natural and energy resources. These are the priorities for future environmental improvement actions that the company may promote.

  12. The influence of surface roughness and high pressure torsion on the growth of anodic titania nanotubes on pure titanium

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Nan; Gao, Nong, E-mail: N.Gao@soton.ac.uk; Starink, Marco J.

    2016-11-30

    Highlights: • HPT has substantially improved the UTS and Hv of pure Ti. • TNT layers was fabricated on UFG Ti made by HPT. • Influence of sample preparation on TNT layers was systematically studied. • Oxide dissolution was accelerated when TNTs formed on the HPT sample. - Abstract: Anodic titanium dioxide nanotube (TNT) arrays have wide applications in photocatalytic, catalysis, electronics, solar cells and biomedical implants. When TNT coatings are combined with severe plastic deformation (SPD), metal processing techniques which efficiently improve the strength of metals, a new generation of biomedical implant is made possible with both improved bulk and surface properties. This work investigated the effect of processing by high pressure torsion (HPT) and different mechanical preparations on the substrate and subsequently on the morphology of TNT layers. HPT processing was applied to refine the grain size of commercially pure titanium samples and substantially improved their strength and hardness. Subsequent anodization at 30 V in 0.25 wt.% NH{sub 4}F for 2 h to form TNT layers on sample surfaces prepared with different mechanical preparation methods was carried out. It appeared that the local roughness of the titanium surface on a microscopic level affected the TNT morphology more than the macroscopic surface roughness. For HPT-processed sample, the substrate has to be pre-treated by a mechanical preparation finer than 4000 grit for HPT to have a significant influence on TNTs. During the formation of TNT layers the oxide dissolution rate was increased for the ultrafine-grained microstructure formed due to HPT processing.

  13. A simple surface treatment and characterization of AA 6061 aluminum alloy surface for adhesive bonding applications

    International Nuclear Information System (INIS)

    Saleema, N.; Sarkar, D.K.; Paynter, R.W.; Gallant, D.; Eskandarian, M.

    2012-01-01

    Highlights: ► A very simple surface treatment method to achieve excellent and durable aluminum adhesive bonding. ► Our method involves simple immersion of aluminum in very dilute NaOH solution at room temperature with no involvement of strong acids or multiple procedures. ► Surface analysis via various surface characterization techniques showed morphological and chemical modifications favorable for obtaining highly durable bond strengths on the treated surface. ► Safe, economical, reproducible and simple method, easily applicable in industries. - Abstract: Structural adhesive bonding of aluminum is widely used in aircraft and automotive industries. It has been widely noted that surface preparation of aluminum surfaces prior to adhesive bonding plays a significant role in improving the strength of the adhesive bond. Surface cleanliness, surface roughness, surface wettability and surface chemistry are controlled primarily by proper surface treatment methods. In this study, we have employed a very simple technique influencing all these criteria by simply immersing aluminum substrates in a very dilute solution of sodium hydroxide (NaOH) and we have studied the effect of varying the treatment period on the adhesive bonding characteristics. A bi-component epoxy adhesive was used to join the treated surfaces and the bond strengths were evaluated via single lap shear (SLS) tests in pristine as well as degraded conditions. Surface morphology, chemistry, crystalline nature and wettability of the NaOH treated surfaces were characterized using various surface analytical tools such as scanning electron microscopy and energy dispersive X-ray analysis (SEM/EDX), optical profilometry, infrared reflection absorption spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and contact angle goniometry. Excellent adhesion characteristics with complete cohesive failure of the adhesive were encountered on the NaOH treated surfaces that are comparable to the benchmark

  14. Surface morphology and surface energy of anode materials influence power outputs in a multi-channel mediatorless bio-photovoltaic (BPV) system.

    Science.gov (United States)

    Bombelli, Paolo; Zarrouati, Marie; Thorne, Rebecca J; Schneider, Kenneth; Rowden, Stephen J L; Ali, Akin; Yunus, Kamran; Cameron, Petra J; Fisher, Adrian C; Ian Wilson, D; Howe, Christopher J; McCormick, Alistair J

    2012-09-21

    Bio-photovoltaic cells (BPVs) are a new photo-bio-electrochemical technology for harnessing solar energy using the photosynthetic activity of autotrophic organisms. Currently power outputs from BPVs are generally low and suffer from low efficiencies. However, a better understanding of the electrochemical interactions between the microbes and conductive materials will be likely to lead to increased power yields. In the current study, the fresh-water, filamentous cyanobacterium Pseudanabaena limnetica (also known as Oscillatoria limnetica) was investigated for exoelectrogenic activity. Biofilms of P. limnetica showed a significant photo response during light-dark cycling in BPVs under mediatorless conditions. A multi-channel BPV device was developed to compare quantitatively the performance of photosynthetic biofilms of this species using a variety of different anodic conductive materials: indium tin oxide-coated polyethylene terephthalate (ITO), stainless steel (SS), glass coated with a conductive polymer (PANI), and carbon paper (CP). Although biofilm growth rates were generally comparable on all materials tested, the amplitude of the photo response and achievable maximum power outputs were significantly different. ITO and SS demonstrated the largest photo responses, whereas CP showed the lowest power outputs under both light and dark conditions. Furthermore, differences in the ratios of light : dark power outputs indicated that the electrochemical interactions between photosynthetic microbes and the anode may differ under light and dark conditions depending on the anodic material used. Comparisons between BPV performances and material characteristics revealed that surface roughness and surface energy, particularly the ratio of non-polar to polar interactions (the CQ ratio), may be more important than available surface area in determining biocompatibility and maximum power outputs in microbial electrochemical systems. Notably, CP was readily outperformed by all

  15. Investigation of the electrochemically active surface area and lithium diffusion in graphite anodes by a novel OsO4 staining method

    Science.gov (United States)

    Pfaffmann, Lukas; Birkenmaier, Claudia; Müller, Marcus; Bauer, Werner; Mitsch, Tim; Feinauer, Julian; Krämer, Yvonne; Scheiba, Frieder; Hintennach, Andreas; Schleid, Thomas; Schmidt, Volker; Ehrenberg, Helmut

    2016-03-01

    Negative electrodes of lithium-ion batteries generally consist of graphite-based active materials. In order to realize batteries with a high current density and therefore accelerated charging processes, the intercalation of lithium and the diffusion processes of these carbonaceous materials must be understood. In this paper, we visualized the electrochemical active surface area for three different anode materials using a novel OsO4 staining method in combination with scanning electron microscopy techniques. The diffusion behavior of these three anode materials is investigated by potentiostatic intermittent titration technique measurements. From those we determine the diffusion coefficient with and without consideration of the electrochemical active surface area.

  16. In-situ study of the gas-phase composition and temperature of an intermediate-temperature solid oxide fuel cell anode surface fed by reformate natural gas

    Science.gov (United States)

    Santoni, F.; Silva Mosqueda, D. M.; Pumiglia, D.; Viceconti, E.; Conti, B.; Boigues Muñoz, C.; Bosio, B.; Ulgiati, S.; McPhail, S. J.

    2017-12-01

    An innovative experimental setup is used for in-depth and in-operando characterization of solid oxide fuel cell anodic processes. This work focuses on the heterogeneous reactions taking place on a 121 cm2 anode-supported cell (ASC) running with a H2, CH4, CO2, CO and steam gas mixture as a fuel, using an operating temperature of 923 K. The results have been obtained by analyzing the gas composition and temperature profiles along the anode surface in different conditions: open circuit voltage (OCV) and under two different current densities, 165 mA cm-2 and 330 mA cm-2, corresponding to 27% and 54% of fuel utilization, respectively. The gas composition and temperature analysis results are consistent, allowing to monitor the evolution of the principal chemical and electrochemical reactions along the anode surface. A possible competition between CO2 and H2O in methane internal reforming is shown under OCV condition and low current density values, leading to two different types of methane reforming: Steam Reforming and Dry Reforming. Under a current load of 40 A, the dominance of exothermic reactions leads to a more marked increase of temperature in the portion of the cell close to the inlet revealing that current density is not uniform along the anode surface.

  17. SnO2 anode surface passivation by atomic layer deposited HfO2 improves li-ion battery performance

    KAUST Repository

    Yesibolati, Nulati

    2014-03-14

    For the first time, it is demonstrated that nanoscale HfO2 surface passivation layers formed by atomic layer deposition (ALD) significantly improve the performance of Li ion batteries with SnO2-based anodes. Specifically, the measured battery capacity at a current density of 150 mAg -1 after 100 cycles is 548 and 853 mAhg-1 for the uncoated and HfO2-coated anodes, respectively. Material analysis reveals that the HfO2 layers are amorphous in nature and conformably coat the SnO2-based anodes. In addition, the analysis reveals that ALD HfO2 not only protects the SnO2-based anodes from irreversible reactions with the electrolyte and buffers its volume change, but also chemically interacts with the SnO2 anodes to increase battery capacity, despite the fact that HfO2 is itself electrochemically inactive. The amorphous nature of HfO2 is an important factor in explaining its behavior, as it still allows sufficient Li diffusion for an efficient anode lithiation/delithiation process to occur, leading to higher battery capacity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Evaporation characteristics of a hydrophilic surface with micro-scale and/or nano-scale structures fabricated by sandblasting and aluminum anodization

    International Nuclear Information System (INIS)

    Kim, Hyungmo; Kim, Joonwon

    2010-01-01

    This paper presents the results of evaporation experiments using water droplets on aluminum sheets that were either smooth or had surface structures at the micro-scale, at the nano-scale or at both micro- and nano-scales (dual-scale). The smooth surface was a polished aluminum sheet; the surface with micro-scale structures was obtained by sandblasting; the surface with nano-scale structures was obtained using conventional aluminum anodization and the surface with dual-scale structures was prepared using sandblasting and anodization sequentially. The wetting properties and evaporation rates were measured for each surface. The evaporation rates were affected by their static and dynamic wetting properties. Evaporation on the surface with dual-scale structures was fastest and the evaporation rate was analyzed quantitatively.

  19. Surface treatment of zirconia ceramics

    International Nuclear Information System (INIS)

    1980-01-01

    A method of chemically micropitting and/or microcratering at least a portion of a smooth surface of an impervious zirconia-base ceramic is described, comprising (a) contacting the smooth surface with a liquid leachant selected from concentrated sulphuric acid, ammonium bisulphate, alkali metal bisulphates and mixtures thereof at a temperature of at least 250 0 C for a period of time sufficient to effect micropitting and/or microcratering generally uniformly distributed throughout the microstructure of the resultant leached surface; (b) removing the leached surface from contact with the leachant; (c) contacting the leached surface with hydrochloric acid to effect removal from the leached surface of a residue thereon comprising sulphate of metal elements including zirconium in the ceramic; (d) removing the leached surface from contact with the hydrochloric acid; and (e) rinsing the leached surface with water to effect removal of acid residue from that surface. (author)

  20. Surface-enhanced Raman scattering of self-assembled thiol monolayers and supported lipid membranes on thin anodic porous alumina

    Directory of Open Access Journals (Sweden)

    Marco Salerno

    2017-01-01

    Full Text Available Thin anodic porous alumina (tAPA was fabricated from a 500 nm thick aluminum (Al layer coated on silicon wafers, through single-step anodization performed in a Teflon electrochemical cell in 0.4 M aqueous phosphoric acid at 110 V. Post-fabrication etching in the same acid allowed obtaining tAPA surfaces with ≈160 nm pore diameter and ≈80 nm corresponding wall thickness to be prepared. The tAPA surfaces were made SERS-active by coating with a thin (≈25 nm gold (Au layer. The as obtained tAPA–Au substrates were incubated first with different thiols, namely mercaptobenzoic acid (MbA and aminothiol (AT, and then with phospholipid vesicles of different composition to form a supported lipid bilayer (SLB. At each step, the SERS substrate functionality was assessed, demonstrating acceptable enhancement (≥100×. The chemisorption of thiols during the first step and the formation of SLB from the vesicles during the second step, were independently monitored by using a quartz crystal microbalance with dissipation monitoring (QCM-D technique. The SLB membranes represent a simplified model system of the living cells membranes, which makes the successful observation of SERS on these films promising in view of the use of tAPA–Au substrates as a platform for the development of surface-enhanced Raman spectroscopy (SERS biosensors on living cells. In the future, these tAPA–Au-SLB substrates will be investigated also for drug delivery of bioactive agents from the APA pores.

  1. Improving domestic wastewater treatment efficiency with constructed wetland microbial fuel cells: Influence of anode material and external resistance.

    Science.gov (United States)

    Corbella, Clara; Puigagut, Jaume

    2018-08-01

    For the past few years, there has been an increasing interest in the operation of constructed wetlands as microbial fuel cells (CW-MFCs) for both the improvement of wastewater treatment efficiency and the production of energy. However, there is still scarce information on design and operation aspects to maximize CW-MFCs efficiency, especially for the treatment of real domestic wastewater. The aim of this study was to quantify the extent of treatment efficiency improvement carried out by membrane-less MFCs simulating a core of a shallow un-planted horizontal subsurface flow constructed wetland. The influence of the external resistance (50, 220, 402, 604 and 1000Ω) and the anode material (graphite and gravel) on treatment efficiency improvement were addressed. To this purpose, 6 lab-scale membrane-less MFCs were set-up and loaded in batch mode with domestic wastewater for 13weeks. Results showed that 220Ω was the best operation condition for maximising MFCs treatment efficiency, regardless the anode material employed. Gravel-based anode MFCs operated at closed circuit showed ca. 18%, 15%, 31% and 25% lower effluent concentration than unconnected MFCs to the COD, TOC, PO 4 -3 and NH 4 + -N, respectively. Main conclusion of the present work is that constructed wetlands operated as MFCs is a promising strategy to improve domestic wastewater treatment efficiency. However, further studies at pilot scale under more realistic conditions (such as planted systems operated under continuous mode) shall be performed to confirm the findings here reported. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Friction Surface Treatment Selection: Aggregate Properties, Surface Characteristics, Alternative Treatments, and Safety Effects

    Science.gov (United States)

    2017-07-01

    This study aimed to evaluate the long term performance of the selected surface friction treatments, including high friction surface treatment (HFST) using calcined bauxite and steel slag, and conventional friction surfacing, in particular pavement pr...

  3. Interfacial Interaction in Anodic Aluminum Oxide Templates Modifies Morphology, Surface Area, and Crystallization of Polyamide-6 Nanofibers.

    Science.gov (United States)

    Xue, Junhui; Xu, Yizhuang; Jin, Zhaoxia

    2016-03-08

    Here, we demonstrated that, when the precipitation process of polyamide-6 (PA6) solution happens in cylindrical channels of an anodized aluminum oxide membrane (AAO), interface interactions between a solid surface, solvent, non-solvent, and PA6 will influence the obtained polymer nanostructures, resulting in complex morphologies, increased surface area, and crystallization changes. With the enhancing interaction of PA6 and the AAO surface, the morphology of PA6 nanostructures changes from solid nanofibers, mesoporous, to bamboo-like, while at the same time, metastable γ-phase domains increase in these PA6 nanostructures. Brunauer-Emmett-Teller (BET) surface areas of solid, bamboo-like, and mesoporous PA6 nanofibers rise from 16, 20.9, to 25 m(2)/g. This study shows that interfacial interaction in AAO template fabrication can be used in manipulating the morphology and crystallization of one-dimensional polymer nanostructures. It also provides us a simple and novel method to create porous PA6 nanofibers with a large surface area.

  4. Study on the fabrication of back surface reflectors in nano-crystalline silicon thin-film solar cells by using random texturing aluminum anodization

    Science.gov (United States)

    Shin, Kang Sik; Jang, Eunseok; Cho, Jun-Sik; Yoo, Jinsu; Park, Joo Hyung; Byungsung, O.

    2015-09-01

    In recent decades, researchers have improved the efficiency of amorphous silicon solar cells in many ways. One of the easiest and most practical methods to improve solar-cell efficiency is adopting a back surface reflector (BSR) as the bottom layer or as the substrate. The BSR reflects the incident light back to the absorber layer in a solar cell, thus elongating the light path and causing the so-called "light trapping effect". The elongation of the light path in certain wavelength ranges can be enhanced with the proper scale of BSR surface structure or morphology. An aluminum substrate with a surface modified by aluminum anodizing is used to improve the optical properties for applications in amorphous silicon solar cells as a BSR in this research due to the high reflectivity and the low material cost. The solar cells with a BSR were formed and analyzed by using the following procedures: First, the surface of the aluminum substrate was degreased by using acetone, ethanol and distilled water, and it was chemically polished in a dilute alkali solution. After the cleaning process, the aluminum surface's morphology was modified by using a controlled anodization in a dilute acid solution to form oxide on the surface. The oxidized film was etched off by using an alkali solution to leave an aluminum surface with randomly-ordered dimple-patterns of approximately one micrometer in size. The anodizing conditions and the anodized aluminum surfaces after the oxide layer had been removed were systematically investigated according to the applied voltage. Finally, amorphous silicon solar cells were deposited on a modified aluminum plate by using dc magnetron sputtering. The surfaces of the anodized aluminum were observed by using field-emission scanning electron microscopy. The total and the diffuse reflectances of the surface-modified aluminum sheets were measured by using UV spectroscopy. We observed that the diffuse reflectances increased with increasing anodizing voltage. The

  5. Method for surface treatment by electron beams

    International Nuclear Information System (INIS)

    Panzer, S.; Doehler, H.; Bartel, R.; Ardenne, T. von.

    1985-01-01

    The invention has been aimed at simplifying the technology and saving energy in modifying surfaces with the aid of electron beams. The described beam-object geometry allows to abandon additional heat treatments. It can be used for surface hardening

  6. Enhancing pitting corrosion resistance of Al{sub x}CrFe{sub 1.5}MnNi{sub 0.5} high-entropy alloys by anodic treatment in sulfuric acid

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C.P.; Chen, Y.Y.; Hsu, C.Y.; Yeh, J.W. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan (China); Shih, H.C. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan (China); Institute of Materials Science and Nanotechnology, Chinese Culture University, Taipei 111, Taiwan (China)], E-mail: hcshih@mx.nthu.edu.tw

    2008-12-01

    High-entropy alloys are a newly developed family of multi-component alloys that comprise various major alloying elements. Each element in the alloy system is present in between 5 and 35 at.%. The crystal structures and physical properties of high-entropy alloys differ completely from those of conventional alloys. The electrochemical impedance spectra (EIS) of the Al{sub x}CrFe{sub 1.5}MnNi{sub 0.5} (x = 0, 0.3, 0.5) alloys, obtained in 0.1 M HCl solution, clearly revealed that the corrosion resistance values were determined to increase from 21 to 34 {omega}cm{sup 2} as the aluminum content increased from 0 to 0.5 mol, and were markedly lower than that of 304 stainless steel (243 {omega}cm{sup 2}). At passive potential, the corresponding current declined with the anodizing time accounting, causing passivity by the growth of the multi-component anodized film in H{sub 2}SO{sub 4} solution. X-ray photoelectron spectroscopy (XPS) analyses revealed that the surface of anodized Al{sub 0.3}CrFe{sub 1.5}MnNi{sub 0.5} alloy formed aluminum and chromium oxide film which was the main passivating compound on the alloy. This anodic treatment increased the corrosion resistance in the EIS measurements of the CrFe{sub 1.5}MnNi{sub 0.5} and Al{sub 0.3}CrFe{sub 1.5}MnNi{sub 0.5} alloys by two orders of magnitude. Accordingly, the anodic treatment of the Al{sub x}CrFe{sub 1.5}MnNi{sub 0.5} alloys optimized their surface structures and minimized their susceptibility to pitting corrosion.

  7. Electrochemical treatment of phenolic waters in presence of chloride with boron-doped diamond (BDD) anodes: Experimental study and mathematical model

    International Nuclear Information System (INIS)

    Mascia, Michele; Vacca, Annalisa; Polcaro, Anna Maria; Palmas, Simonetta; Ruiz, Jesus Rodriguez; Da Pozzo, Anna

    2010-01-01

    This work deals with an experimental and numerical study on the electrochemical treatment of waters containing phenolic compounds with boron-doped diamond (BDD) anodes. Anodic oxidation of m-cresol, as a model of phenolic compound, was investigated by galvanostatic electrolyses. The electrolyses were carried out under different experimental conditions by using an impinging-jet flow cell inserted in a hydraulic circuit in a closed loop. On the basis of the experimental results a mathematical model was implemented to simulate the effect of the chemistry of organic compounds and solution on the process, in particular the effect of chlorides on the kinetics of m-cresol oxidation. The effect of hydrodynamics of the cell on the mass transfer towards the electrode surface was also considered. The model was validated through comparison with experimental data: the results showed that the proposed model well interpreted the complex effect on removal efficiency of such operative parameters as current density, hydrodynamic of the reactor and chemistry of the solution. The model predictions were utilised to obtain quantitative information on the reaction mechanism, as well as to predict the performance of the process under different operative conditions, by calculating some relevant figures of merit.

  8. Process for surface treatment of zirconium-containing cladding materials for fuel element or other components for nuclear reactors

    International Nuclear Information System (INIS)

    Videm, K.G.; Lunde, L.R.; Kooyman, H.H.

    1975-01-01

    A process for the surface treatment of zirconium-base cladding materials for fuel elements or other components for nuclear reactors is described. The treatment includes pickling the cladding material in a fluoride-containing bath, and then applying a protective coating through oxidation to the pickled cladding material. The fluoride-containing contaminants which remain on the surface of the cladding material during pickling are removed or rendered harmless by anodic oxidation

  9. SnO2 anode surface passivation by atomic layer deposited HfO2 improves li-ion battery performance

    KAUST Repository

    Yesibolati, Nulati; Shahid, Muhammad; Chen, Wei; Hedhili, Mohamed N.; Reuter, Mark C.; Ross, Frances M.; Alshareef, Husam N.

    2014-01-01

    For the first time, it is demonstrated that nanoscale HfO2 surface passivation layers formed by atomic layer deposition (ALD) significantly improve the performance of Li ion batteries with SnO2-based anodes. Specifically, the measured battery

  10. Surface-modified anodic aluminum oxide membrane with hydroxyethyl celluloses as a matrix for bilirubin removal.

    Science.gov (United States)

    Xue, Maoqiang; Ling, Yisheng; Wu, Guisen; Liu, Xin; Ge, Dongtao; Shi, Wei

    2013-01-01

    Microporous anodic aluminum oxide (AAO) membranes were modified by 3-glycidoxypropyltrimethoxysilane to produce terminal epoxy groups. These were used to covalently link hydroxyethyl celluloses (HEC) to amplify reactive groups of AAO membrane. The hydroxyl groups of HEC-AAO composite membrane were further modified with 1,4-butanediol diglycidyl ether to link arginine as an affinity ligand. The contents of HEC and arginine of arginine-immobilized HEC-AAO membrane were 52.1 and 19.7mg/g membrane, respectively. As biomedical adsorbents, the arginine-immobilized HEC-AAO membranes were tested for bilirubin removal. The non-specific bilirubin adsorption on the unmodified HEC-AAO composite membranes was 0.8mg/g membrane. Higher bilirubin adsorption values, up to 52.6mg/g membrane, were obtained with the arginine-immobilized HEC-AAO membranes. Elution of bilirubin showed desorption ratio was up to 85% using 0.3M NaSCN solution as the desorption agent. Comparisons equilibrium and dynamic capacities showed that dynamic capacities were lower than the equilibrium capacities. In addition, the adsorption mechanism of bilirubin and the effects of temperature, initial concentration of bilirubin, albumin concentration and ionic strength on adsorption were also investigated. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Post-heat treatment of arc-sprayed coating prepared by the wires combination of Mg-cathode and Al-anode to form protective intermetallic layers

    International Nuclear Information System (INIS)

    Xu Rongzheng; Song Gang

    2011-01-01

    A Mg-Al intermetallic compounds coating was prepared on the surface of Mg-steel lap joint by arc-sprayed Al-Mg composite coating (Mg-cathode and Al-anode) and its post-heat treatment (PHT). The effect of PHT temperature on the phase transition, microstructure and mechanical properties of the coating was investigated by X-ray diffraction, scanning electron microscope, energy dispersive X-ray spectroscopy, optical microscope and microhardness test. The result shows that the intermetallic compounds layer that is mainly composed of Al 3 Mg 2 and Mg 17 Al 12 is formed by the self-diffusion reaction of Mg and Al splats in the coating after PHT for 4 h at 430 deg. C.

  12. Surface treatment of ceramic articles

    International Nuclear Information System (INIS)

    Komvopoulos, K.; Brown, I.G.; Wei, B.; Anders, S.; Anders, A.; Bhatia, C.S.

    1998-01-01

    A process is disclosed for producing an article with improved ceramic surface properties including providing an article having a ceramic surface, and placing the article onto a conductive substrate holder in a hermetic enclosure. Thereafter a low pressure ambient is provided in the hermetic enclosure. A plasma including ions of solid materials is produced the ceramic surface of the article being at least partially immersed in a macroparticle free region of the plasma. While the article is immersed in the macroparticle free region, a bias of the substrate holder is biased between a low voltage at which material from the plasma condenses on the surface of the article and a high negative voltage at which ions from the plasma are implanted into the article. 15 figs

  13. Dynamics of the spatial structure of pulsed discharges in dense gases in point cathode−plane anode gaps and their erosion effect on the plane electrode surface

    International Nuclear Information System (INIS)

    Baksht, E. Kh.; Blinova, O. M.; Erofeev, M. V.; Karelin, V. I.; Ripenko, V. S.; Tarasenko, V. F.; Trenkin, A. A.; Shibitov, Yu. M.; Shulepov, M. A.

    2016-01-01

    The dynamics of the spatial structure of the plasma of pulsed discharges in air and nitrogen in a nonuniform electric field and their erosion effect on the plane anode surface were studied experimentally. It is established that, at a nanosecond front of the voltage pulse, a diffuse discharge forms in the point cathode–plane anode gap due to the ionization wave propagating from the cathode. As the gap length decreases, the diffuse discharge transforms into a spark. A bright spot on the anode appears during the diffuse discharge, while the spark channel forms in the later discharge stage. The microstructure of autographs of anode spots and spark channels in discharges with durations of several nanoseconds is revealed. The autographs consist of up to 100 and more microcraters 5–100 μm in diameter. It is shown that, due to the short duration of the voltage pulse, a diffuse discharge can be implemented, several pulses of which do not produce appreciable erosion on the plane anode or the soot coating deposited on it.

  14. Electrochemical oxidation of tetracycline antibiotics using a Ti/IrO2 anode for wastewater treatment of animal husbandry.

    Science.gov (United States)

    Miyata, M; Ihara, I; Yoshid, G; Toyod, K; Umetsu, K

    2011-01-01

    In animal husbandry, antibiotics are widely used to treat and prevent diseases or to promote growth. The use of antibiotics for domestic animals enables to promote safety of livestock products and enhance productivity. Tetracycline antibiotics (TCs) are one of the primarily used groups of antibiotics for cattle and swine. However, the unintentional spreading of antibiotics from animal waste to the environment may leave out drug residues, promoting resistant strains of bacteria, and will adversely affect the ecosystem and human health. To prevent the spread of veterinary antibiotics in the environment, it is required to treat residual antibiotics in livestock wastewater. In this study, we investigated the electrochemical oxidation of TCs to treat livestock wastewater. The concentrations of TCs in aqueous solutions were reduced from 100 mg/L to less than 0.6 mg/L by 6 h of electrochemical treatment using a Ti/IrO2 anode with Na2SO4 electrolyte. The concentration of oxytetracycline (OTC) in livestock wastewater was also reduced from 100 mg/L to less than 0.7 mg/L by the same treatment. Thus, the electrochemical oxidation using a Ti/IrO2 anode with Na2SO4 electrolyte was found to be effective for degradation of TCs. The results suggest that the electrochemical oxidation method is a promising treatment for TCs in livestock wastewater.

  15. Observation of gliding arc surface treatment

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Zhu, Jiajian; Ehn, A.

    2015-01-01

    . Water contact angle measurements indicate that the treatment uniformity improves significantly when the AC gliding arc is tilted to the polymer surface. Thickness reduction of the gas boundary layer, explaining the improvement of surface treatment, by the ultrasonic irradiation was directly observed...

  16. High Friction Surface Treatments, Transportation Research Synthesis

    Science.gov (United States)

    2018-03-01

    MnDOT and local transportation agencies in Minnesota are considering the use of a high friction surface treatment (HFST) as a safety strategy. HFST is used as a spot pavement surfacing treatment in locations with high friction demand (for example, cr...

  17. [Influence of different surface treatments on porcelain surface topography].

    Science.gov (United States)

    Tai, Yinxia; Zhu, Xianchun; Sen, Yan; Liu, Chang; Zhang, Xian; Shi, Xueming

    2013-02-01

    To evaluate the influence of different surface treatments on porcelain surface topography. Metal ceramic prostheses in 6 groups were treated according to the different surface treatment methods, and the surface topography was observed through scanning electron microscope (SEM). Group A was the control one (untreated), group B was etched by 9.6% hydrofluoric acid(HF), group C was deglazed by grinding and then etched by 9.6% HF, group D was treated with Nd: YAG laser irradiation(0.75 W) and HF etching, group E was treated with Nd: YAG laser irradiation (1.05 W) and HF etching, and group F was treated with laser irradiation (1.45 W) and HF etching. Surface topography was different in different groups. A lot of inerratic cracks with the shapes of rhombuses and grid, and crater with a shape of circle were observed on the ceramic surface after treatment with energy parameters of 1.05 W Nd: YAG laser irradiation and 9.6% HF etching (group E). Surface topography showed a lot of concaves on the inner wall of the cracks, and the concaves with diameter of 1-5 microm could be observed on the inner wall of the holes, which had a diameter of 20 microm under SEM. The use of Nd: YAG laser irradiation with the energy parameters of 1.05 W and the HF with a concentration of 9.6% can evenly coarsen the porcelain surface, that is an effective surface treatment method.

  18. Modeling of ion beam surface treatment

    Energy Technology Data Exchange (ETDEWEB)

    Stinnett, R W [Quantum Manufacturing Technologies, Inc., Albuquerque, NM (United States); Maenchen, J E; Renk, T J [Sandia National Laboratories, Albuquerque, NM (United States); Struve, K W [Mission Research Corporation, Albuquerque, NM (United States); Campbell, M M [PASTDCO, Albuquerque, NM (United States)

    1997-12-31

    The use of intense pulsed ion beams is providing a new capability for surface engineering based on rapid thermal processing of the top few microns of metal, ceramic, and glass surfaces. The Ion Beam Surface Treatment (IBEST) process has been shown to produce enhancements in the hardness, corrosion, wear, and fatigue properties of surfaces by rapid melt and re-solidification. A new code called IBMOD was created, enabling the modeling of intense ion beam deposition and the resulting rapid thermal cycling of surfaces. This code was used to model the effect of treatment of aluminum, iron, and titanium using different ion species and pulse durations. (author). 3 figs., 4 refs.

  19. High Surface Area Iridium Anodes and Melt Containers for Molten Oxide Electrolysis, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Direct electrochemical reduction of molten regolith is the most attractive method of oxygen production on the lunar surface, because no additional chemical reagents...

  20. Effect of heat treatment on stability of gold particle modified carbon supported Pt-Ru anode catalysts for a direct methanol fuel cell

    International Nuclear Information System (INIS)

    Li Xiaowei; Liu Juanying; Huang Qinghong; Vogel, Walter; Akins, Daniel L.; Yang Hui

    2010-01-01

    Carbon supported Au-PtRu (Au-PtRu/C) catalysts were prepared as the anodic catalysts for the direct methanol fuel cell (DMFC). The procedure involved simple deposition of Au particles on a commercial Pt-Ru/C catalyst, followed by heat treatment of the resultant composite catalyst at 125, 175 and 200 o C in a N 2 atmosphere. High-resolution transmission electron microscopy (HR-TEM) measurements indicated that the Au nanoparticles were attached to the surface of the Pt-Ru nanoparticles. We found that the electrocatalytic activity and stability of the Au-PtRu/C catalysts for methanol oxidation is better than that of the PtRu/C catalyst. An enhanced stability of the electrocatalyst is observed and attributable to the promotion of CO oxidation by the Au nanoparticles adsorbed onto the Pt-Ru particles, by weakening the adsorption of CO, which can strongly adsorb to and poison Pt catalyst. XPS results show that Au-PtRu/C catalysts with heat treatment lead to surface segregation of Pt metal and an increase in the oxidation state of Ru, which militates against the dissolution of Ru. We additionally find that Au-PtRu/C catalysts heat-treated at 175 o C exhibit the highest electrocatalytic stability among the catalysts prepared by heat treatment: this observation is explained as due to the attainment of the highest relative concentration of gold and the highest oxidation state of Ru oxides for the catalyst pretreated at this temperature.

  1. Effects of anodic potential and chloride ion on overall reactivity in electrochemical reactors designed for solar-powered wastewater treatment.

    Science.gov (United States)

    Cho, Kangwoo; Qu, Yan; Kwon, Daejung; Zhang, Hao; Cid, Clément A; Aryanfar, Asghar; Hoffmann, Michael R

    2014-02-18

    We have investigated electrochemical treatment of real domestic wastewater coupled with simultaneous production of molecular H2 as useful byproduct. The electrolysis cells employ multilayer semiconductor anodes with electroactive bismuth-doped TiO2 functionalities and stainless steel cathodes. DC-powered laboratory-scale electrolysis experiments were performed under static anodic potentials (+2.2 or +3.0 V NHE) using domestic wastewater samples, with added chloride ion in variable concentrations. Greater than 95% reductions in chemical oxygen demand (COD) and ammonium ion were achieved within 6 h. In addition, we experimentally determined a decreasing overall reactivity of reactive chlorine species toward COD with an increasing chloride ion concentration under chlorine radicals (Cl·, Cl2(-)·) generation at +3.0 V NHE. The current efficiency for COD removal was 12% with the lowest specific energy consumption of 96 kWh kgCOD(-1) at the cell voltage of near 4 V in 50 mM chloride. The current efficiency and energy efficiency for H2 generation were calculated to range from 34 to 84% and 14 to 26%, respectively. The hydrogen comprised 35 to 60% by volume of evolved gases. The efficacy of our electrolysis cell was further demonstrated by a 20 L prototype reactor totally powered by a photovoltaic (PV) panel, which was shown to eliminate COD and total coliform bacteria in less than 4 h of treatment.

  2. Anode biofilm transcriptomics reveals outer surface components essential for high density current production in Geobacter sulfurreducens fuel cells.

    Directory of Open Access Journals (Sweden)

    Kelly P Nevin

    Full Text Available The mechanisms by which Geobacter sulfurreducens transfers electrons through relatively thick (>50 microm biofilms to electrodes acting as a sole electron acceptor were investigated. Biofilms of Geobacter sulfurreducens were grown either in flow-through systems with graphite anodes as the electron acceptor or on the same graphite surface, but with fumarate as the sole electron acceptor. Fumarate-grown biofilms were not immediately capable of significant current production, suggesting substantial physiological differences from current-producing biofilms. Microarray analysis revealed 13 genes in current-harvesting biofilms that had significantly higher transcript levels. The greatest increases were for pilA, the gene immediately downstream of pilA, and the genes for two outer c-type membrane cytochromes, OmcB and OmcZ. Down-regulated genes included the genes for the outer-membrane c-type cytochromes, OmcS and OmcT. Results of quantitative RT-PCR of gene transcript levels during biofilm growth were consistent with microarray results. OmcZ and the outer-surface c-type cytochrome, OmcE, were more abundant and OmcS was less abundant in current-harvesting cells. Strains in which pilA, the gene immediately downstream from pilA, omcB, omcS, omcE, or omcZ was deleted demonstrated that only deletion of pilA or omcZ severely inhibited current production and biofilm formation in current-harvesting mode. In contrast, these gene deletions had no impact on biofilm formation on graphite surfaces when fumarate served as the electron acceptor. These results suggest that biofilms grown harvesting current are specifically poised for electron transfer to electrodes and that, in addition to pili, OmcZ is a key component in electron transfer through differentiated G. sulfurreducens biofilms to electrodes.

  3. Laser Surface Treatment of Sintered Alumina

    Science.gov (United States)

    Hagemann, R.; Noelke, C.; Kaierle, S.; Wesling, V.

    Sintered alumina ceramics are used as refractory materials for industrial aluminum furnaces. In this environment the ceramic surface is in permanent contact with molten aluminum resulting in deposition of oxidic material on its surface. Consequently, a lower volume capacity as well as thermal efficiency of the furnaces follows. To reduce oxidic adherence of the ceramic material, two laser-based surface treatment processes were investigated: a powder- based single-step laser cladding and a laser surface remelting. Main objective is to achieve an improved surface quality of the ceramic material considering the industrial requirements as a high process speed.

  4. Indirect anodic oxidation applied for treatment of simulated wastewater containing Cationic Red X-GRL and Disperse Red 3B

    Directory of Open Access Journals (Sweden)

    Bo Yang

    2017-06-01

    Full Text Available The treatment of simulated wastewater containing Cationic Red X-GRL (X-GRL or Disperse Red 3B (DR-3B dye was carried out by indirect anodic oxidation, using Ti/SnO2 electrodes as the anode. The influences of pH value, voltage, electrolysis time and sodium chloride dosage on the degradation performance were studied by single factor experiment. Furthermore the nitrogen states and UV-Vis spectra in dyes degradation were analyzed. The results showed that under the optimum condition (pH = 3, voltage = 20 V, NaCl = 2.5 g/L, the decolorization and chemical oxygen demand removal of X-GRL were 98% and 67%, respectively; and those of DR-3B were 51% and 61%, respectively. The azo double bond conjugated system in X-GRL is much more easily destroyed than the anthraquinone conjugated system in DR-3B; the aryl ring structures of them can be partially degraded.

  5. Preparation of mesoporous alumina films by anodization: Effect of pretreatments on the aluminum surface and MTBE catalytic oxidation

    International Nuclear Information System (INIS)

    Vazquez, A.L.; Carrera, R.; Arce, E.; Castillo, N.; Castillo, S.; Moran-Pineda, M.

    2009-01-01

    Mesoporous materials are both scientifically and technologically important because of the presence of voids of controllable dimensions at atomic, molecular, and nanometric scales. Over the last decade, there has been both an increasing interest and research effort in the synthesis and characterization of these types of materials. The purposes of this work are to study the physical and chemical changes in the properties of mesoporous alumina films produced by anodization in sulphuric acid by different pretreatments on the aluminium surface such as mechanical polishing [MP] and electropolishing [EP]; and to compare their properties such as morphology, structure and catalytic activity with those present in commercial alumina. The morphologic and physical characterizations of the alumina film samples were carried out by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The chemical evaluations were performed by the oxidation of methyl-tert-butyl-ether (MTBE) at 400 deg. C under O 2 /He oxidizing conditions (Praxair, 2.0% O 2 /He balance). According to the results, the samples that presented higher activities than those in Al 2 O 3 /Al [MP] and commercial alumina in the MTBE oxidation (69%), were those prepared by Al 2 O 3 /Al [EP]. The average mesoporous diameter was 17 nm, and the morphological shape was equiaxial; thus, that pore distribution was the smallest of all with a homogeneous distribution.

  6. Preparation of mesoporous alumina films by anodization: Effect of pretreatments on the aluminum surface and MTBE catalytic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez, A.L., E-mail: avazquezd@ipn.m [Departamento de Ingenieria Metalurgica, ESIQIE-IPN, AP 75-876, Mexico, D.F. (Mexico); Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, C.P. 07730, Mexico, D.F. (Mexico); Carrera, R. [Departamento de Ingenieria Metalurgica, ESIQIE-IPN, AP 75-876, Mexico, D.F. (Mexico); Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, C.P. 07730, Mexico, D.F. (Mexico); Arce, E. [Departamento de Ingenieria Metalurgica, ESIQIE-IPN, AP 75-876, Mexico, D.F. (Mexico); Castillo, N. [CINVESTAV, Departamento de Fisica. Av. IPN 2508, 07360, Mexico, D.F (Mexico); Castillo, S. [Departamento de Ingenieria Metalurgica, ESIQIE-IPN, AP 75-876, Mexico, D.F. (Mexico); Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, C.P. 07730, Mexico, D.F. (Mexico); Moran-Pineda, M. [Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, C.P. 07730, Mexico, D.F. (Mexico)

    2009-08-26

    Mesoporous materials are both scientifically and technologically important because of the presence of voids of controllable dimensions at atomic, molecular, and nanometric scales. Over the last decade, there has been both an increasing interest and research effort in the synthesis and characterization of these types of materials. The purposes of this work are to study the physical and chemical changes in the properties of mesoporous alumina films produced by anodization in sulphuric acid by different pretreatments on the aluminium surface such as mechanical polishing [MP] and electropolishing [EP]; and to compare their properties such as morphology, structure and catalytic activity with those present in commercial alumina. The morphologic and physical characterizations of the alumina film samples were carried out by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The chemical evaluations were performed by the oxidation of methyl-tert-butyl-ether (MTBE) at 400 deg. C under O{sub 2}/He oxidizing conditions (Praxair, 2.0% O{sub 2}/He balance). According to the results, the samples that presented higher activities than those in Al{sub 2}O{sub 3}/Al [MP] and commercial alumina in the MTBE oxidation (69%), were those prepared by Al{sub 2}O{sub 3}/Al [EP]. The average mesoporous diameter was 17 nm, and the morphological shape was equiaxial; thus, that pore distribution was the smallest of all with a homogeneous distribution.

  7. Self-organized pattern on the surface of a metal anode in low-pressure DC discharge

    Science.gov (United States)

    Yaqi, YANG; Weiguo, LI

    2018-03-01

    Self-organization phenomena on the surface of a metal electrode in low-pressure DC discharge is studied. In this paper, we carry out laboratory investigations of self-organization in a low-pressure test platform for 100-200 mm rod-plane gaps with a needle tip, conical tip and hemispherical tip within 1-10 kPa. The factors influencing the pattern profile are the pressure value, gap length and shape of the electrode, and a variety of pattern structures are observed by changing these factors. With increasing pressure, first the pattern diameter increases and then decreases. With the needle tip, layer structure, single-ring structure and double-ring structure are displayed successively with increasing pressure. With the conical tip, the ring-like structure gradually forms separate spots with increasing pressure. With the hemispherical tip, there are anode spots inside the ring structure. With the increase of gap length, the diameter of the self-organized pattern increases and the profile of the pattern changes. The development process of the pattern contains three key stages: pattern enlargement, pattern stabilization and pattern shrink.

  8. Plasma treatment of porous GaAs surface formed by electrochemical etching method: Characterization and properties

    International Nuclear Information System (INIS)

    Saloum, S.; Naddaf, M.

    2010-01-01

    Porous GaAs samples were formed by electrochemical anodic etching of Zn doped p-type GaAs (100) wafers at different etching parameters (time, mode of applied voltage or current and electrolyte). The effect of etching parameters and plasma surface treatment on the optical properties of the prepared sample has been investigated by using room temperature photoluminescence (PL), Raman spectroscopy and reflectance spectroscopic measurements in the range (400-800 nm). The surface morphological changes were studied by using atomic force microscope. (author)

  9. Surface characterisation and functionalisation of indium tin oxide anodes for improvement of charge injection in organic light emitting diodes

    International Nuclear Information System (INIS)

    Davenas, J.; Besbes, S.; Abderrahmen, A.; Jaffrezic, N.; Ben Ouada, H.

    2008-01-01

    Wettability studies have been performed to probe the surface properties of ITO substrates, aimed to be used as hole injecting electrode in OLEDs. The elimination of organic contaminants upon the cleaning treatment (ultrasonic bath in organic solvents) leads to an increase of the free energy of the ITO surface becoming hydrophilic. The surface energy components calculated from the Van Oss model show the appearance of a basic component upon the cleaning treatment. A thermal treatment at 100 deg. C for 3 h leads to a decrease of the surface free energy due to surface dehydration. These properties are attributed to the hydroxides formed at the ITO surface inducing improved adhesion at the ITO/polymer interface. The ITO surfaces have been functionalised with a chloroethylphosphonic acid mono-layer to increase their stability. The appearance of an acid-base component leads to a dipolar character of the ITO surface. The formation of a compact layer of a spin coated poly(phenylenevinylene) derivative induces the shielding of the ITO basic character. The weakening of the near infrared absorption associated to ITO free carriers confirms the formation of a dipole layer at the interface with the molecular layer in contact with ITO. Improved injection properties, shown by the current/voltage characteristics, result from the interface modifications

  10. Sequential Vapor Infiltration Treatment Enhances the Ionic Current Rectification Performance of Composite Membranes Based on Mesoporous Silica Confined in Anodic Alumina.

    Science.gov (United States)

    Liang, Yanyan; Liu, Zhengping

    2016-12-20

    Ionic current rectification of nanofluidic diode membranes has been studied widely in recent years because it is analogous to the functionality of biological ion channels in principle. We report a new method to fabricate ionic current rectification membranes based on mesoporous silica confined in anodic aluminum oxide (AAO) membranes. Two types of mesostructured silica nanocomposites, hexagonal structure and nanoparticle stacked structure, were used to asymmetrically fill nanochannels of AAO membranes by a vapor-phase synthesis (VPS) method with aspiration approach and were further modified via sequence vapor infiltration (SVI) treatment. The ionic current measurements indicated that SVI treatment can modulate the asymmetric ionic transport in prepared membranes, which exhibited clear ionic current rectification phenomenon under optimal conditions. The ionic current rectifying behavior is derived from the asymmetry of surface conformations, silica species components, and hydrophobic wettability, which are created by the asymmetrical filling type, silica depositions on the heterogeneous membranes, and the condensation of silanol groups. This article provides a considerable strategy to fabricate composite membranes with obvious ionic current rectification performance via the cooperation of the VPS method and SVI treatment and opens up the potential of mesoporous silica confined in AAO membranes to mimic fluid transport in biological processes.

  11. Effect of electrochemical treatments on the surface chemistry of activated carbon

    OpenAIRE

    Berenguer Betrián, Raúl; Marco Lozar, Juan Pablo; Quijada Tomás, César; Cazorla Amorós, Diego; Morallón Núñez, Emilia

    2008-01-01

    The effect of the electrochemical treatment (galvanostatic electrolysis in a filter-press electrochemical cell) on the surface chemistry and porous structure of a granular activated carbon (GAC) has been analyzed by means of temperature-programmed desorption and N2 (at 77 K) and CO2 (at 273 K) adsorption isotherms. The anodic and cathodic treatments, the applied current (between 0.2 and 2.0 A) and the type of electrolyte (NaOH, H2SO4 and NaCl)have been studied as electrochemical variables. Bo...

  12. Evaluation of Ti-6Al-4V surface treatments for use with a polyphenylquinoxaline adhesive

    Science.gov (United States)

    Progar, Donald J.

    1987-01-01

    Three surface treatments for Ti-6Al-4V adherends were evaluated using a thermoplastic polymer monoether polyphenylquinoxaline, MEPPQ, which had been shown in previous studies to have good potential as a high temperature adhesive for aerospace applications. Initial results based on long term thermal exposure at 232 C (450 F) using the phosphate-fluoride (PF) and chromic acid anodized (CAA) treatments with MEPPQ adhesive were not encouraging. A significant improvement in strength retention and a change in failure mode (cohesive) at 232 C (450 F) was found for the SHA treated specimens compared to the PF and CAA treatments. Although an improvement in long term thermal durability was obtained with the SHA treatment of Ti-6Al-4V, an improved surface treatment with better long term durability is still required for aerospace applications.

  13. Anodic oxidation

    CERN Document Server

    Ross, Sidney D; Rudd, Eric J; Blomquist, Alfred T; Wasserman, Harry H

    2013-01-01

    Anodic Oxidation covers the application of the concept, principles, and methods of electrochemistry to organic reactions. This book is composed of two parts encompassing 12 chapters that consider the mechanism of anodic oxidation. Part I surveys the theory and methods of electrochemistry as applied to organic reactions. These parts also present the mathematical equations to describe the kinetics of electrode reactions using both polarographic and steady-state conditions. Part II examines the anodic oxidation of organic substrates by the functional group initially attacked. This part particular

  14. Surface Passivation of MoO3 Nanorods by Atomic Layer Deposition Towards High Rate Durable Li Ion Battery Anodes

    KAUST Repository

    Ahmed, Bilal

    2015-06-03

    We demonstrate an effective strategy to overcome the degradation of MoO3 nanorod anodes in Lithium (Li) ion batteries at high rate cycling. This is achieved by conformal nanoscale surface passivation of the MoO3 nanorods by HfO2 using atomic layer deposition (ALD). At high current density such as 1500 mA/g, the specific capacity of HfO2 coated MoO3 electrodes is 68% higher than bare MoO3 electrodes after 50 charge/discharge cycles. After 50 charge/discharge cycles, HfO2 coated MoO3 electrodes exhibited specific capacity of 657 mAh/g, on the other hand, bare MoO3 showed only 460 mAh/g. Furthermore, we observed that HfO2 coated MoO3 electrodes tend to stabilize faster than bare MoO3 electrodes because nanoscale HfO2 layer prevents structural degradation of MoO3 nanorods. Additionally, the growth temperature of MoO3 nanorods and the effect of HfO2 layer thickness was studied and found to be important parameters for optimum battery performance. The growth temperature defines the microstructural features and HfO2 layer thickness defines the diffusion coefficient of Li–ions through the passivation layer to the active material. Furthermore, ex–situ HRTEM, X–ray photoelectron spectroscopy (XPS), Raman spectroscopy and X–ray diffraction was carried out to explain the capacity retention mechanism after HfO2 coating.

  15. Surface Passivation of MoO3 Nanorods by Atomic Layer Deposition Towards High Rate Durable Li Ion Battery Anodes

    KAUST Repository

    Ahmed, Bilal; Shahid, Muhammad; Nagaraju, Doddahalli H.; Anjum, Dalaver H.; Hedhili, Mohamed N.; Alshareef, Husam N.

    2015-01-01

    We demonstrate an effective strategy to overcome the degradation of MoO3 nanorod anodes in Lithium (Li) ion batteries at high rate cycling. This is achieved by conformal nanoscale surface passivation of the MoO3 nanorods by HfO2 using atomic layer deposition (ALD). At high current density such as 1500 mA/g, the specific capacity of HfO2 coated MoO3 electrodes is 68% higher than bare MoO3 electrodes after 50 charge/discharge cycles. After 50 charge/discharge cycles, HfO2 coated MoO3 electrodes exhibited specific capacity of 657 mAh/g, on the other hand, bare MoO3 showed only 460 mAh/g. Furthermore, we observed that HfO2 coated MoO3 electrodes tend to stabilize faster than bare MoO3 electrodes because nanoscale HfO2 layer prevents structural degradation of MoO3 nanorods. Additionally, the growth temperature of MoO3 nanorods and the effect of HfO2 layer thickness was studied and found to be important parameters for optimum battery performance. The growth temperature defines the microstructural features and HfO2 layer thickness defines the diffusion coefficient of Li–ions through the passivation layer to the active material. Furthermore, ex–situ HRTEM, X–ray photoelectron spectroscopy (XPS), Raman spectroscopy and X–ray diffraction was carried out to explain the capacity retention mechanism after HfO2 coating.

  16. Fabrication of Nano-Micro Hybrid Structures by Replication and Surface Treatment of Nanowires

    Directory of Open Access Journals (Sweden)

    Yeonho Jeong

    2017-07-01

    Full Text Available Nanowire structures have attracted attention in various fields, since new characteristics could be acquired in minute regions. Especially, Anodic Aluminum Oxide (AAO is widely used in the fabrication of nanostructures, which has many nanosized pores and well-organized nano pattern. Using AAO as a template for replication, nanowires with a very high aspect ratio can be fabricated. Herein, we propose a facile method to fabricate a nano-micro hybrid structure using nanowires replicated from AAO, and surface treatment. A polymer resin was coated between Polyethylene terephthalate (PET and the AAO filter, roller pressed, and UV-cured. After the removal of aluminum by using NaOH solution, the nanowires aggregated to form a micropattern. The resulting structure was subjected to various surface treatments to investigate the surface behavior and wettability. As opposed to reported data, UV-ozone treatment can enhance surface hydrophobicity because the UV energy affects the nanowire surface, thus altering the shape of the aggregated nanowires. The hydrophobicity of the surface could be further improved by octadecyltrichlorosilane (OTS coating immediately after UV-ozone treatment. We thus demonstrated that the nano-micro hybrid structure could be formed in the middle of nanowire replication, and then, the shape and surface characteristics could be controlled by surface treatment.

  17. Surface study of stainless steel electrode deposition from soil electrokinetic (EK) treatment using X-ray photoelectron spectroscopy (XPS)

    International Nuclear Information System (INIS)

    Embong, Zaidi; Johar, Saffuwan; Tajudin, Saiful Azhar Ahmad; Sahdan, Mohd Zainizan

    2015-01-01

    Electrokinetic (EK) remediation relies upon application of a low-intensity direct current through the soil between stainless steel electrodes that are divided into a cathode array and an anode array. This mobilizes charged species, causing ions and water to move toward the electrodes. Metal ions and positively charged organic compounds move toward the cathode. Anions such as chloride, fluoride, nitrate, and negatively charged organic compounds move toward the anode. Here, this remediation techniques lead to a formation of a deposition at the both cathode and anode surface that mainly contributed byanion and cation from the remediated soil. In this research, Renggam-Jerangau soil species (HaplicAcrisol + RhodicFerralsol) with a surveymeter reading of 38.0 ± 3.9 μR/hr has been investigation in order to study the mobility of the anion and cation under the influence electric field. Prior to the EK treatment, the elemental composition of the soil and the stainless steel electrode are measured using XRF analyses. Next, the soil sample is remediated at a constant electric potential of 30 V within an hour of treatment period. A surface study for the deposition layer of the cathode and anode using X-ray Photoelectron spectroscopy (XPS) revealed that a narrow photoelectron signal from oxygen O 1s, carbon, C 1s silica, Si 2p, aluminium, Al 2p and chromium, Cr 2p exhibited on the electrode surface and indicate that a different in photoelectron intensity for each element on both electrode surface. In this paper, the mechanism of Si 2+ and Al 2+ cation mobility under the influence of voltage potential between the cathode and anode will be discussed in detail

  18. Surface study of stainless steel electrode deposition from soil electrokinetic (EK) treatment using X-ray photoelectron spectroscopy (XPS)

    Energy Technology Data Exchange (ETDEWEB)

    Embong, Zaidi, E-mail: zaidi@uthm.edu.my [Faculty of Science, Technology and Human Development, Universiti Tun Hussien Onn Malaysia (UTHM) 86400, Parit Raja, Batu, Johor (Malaysia); Research Centre for Soft Soils (RECESS), Office for Research, Innovation, Commercialization and Consultancy Management (ORICC), Universiti Tun Hussien Onn Malaysia UTHM 86400, Parit Raja, Batu, Johor (Malaysia); Johar, Saffuwan [Faculty of Science, Technology and Human Development, Universiti Tun Hussien Onn Malaysia (UTHM) 86400, Parit Raja, Batu, Johor (Malaysia); Tajudin, Saiful Azhar Ahmad [Research Centre for Soft Soils (RECESS), Office for Research, Innovation, Commercialization and Consultancy Management (ORICC), Universiti Tun Hussien Onn Malaysia UTHM 86400, Parit Raja, Batu, Johor (Malaysia); Sahdan, Mohd Zainizan [Microelectronics and Nanotechnology Centre (MiNT-SRC), Office for Research, Innovation, Commercialization and Consultancy Management (ORICC), Universiti Tun Hussien Onn Malaysia UTHM 86400, Parit Raja, Batu, Johor (Malaysia)

    2015-04-29

    Electrokinetic (EK) remediation relies upon application of a low-intensity direct current through the soil between stainless steel electrodes that are divided into a cathode array and an anode array. This mobilizes charged species, causing ions and water to move toward the electrodes. Metal ions and positively charged organic compounds move toward the cathode. Anions such as chloride, fluoride, nitrate, and negatively charged organic compounds move toward the anode. Here, this remediation techniques lead to a formation of a deposition at the both cathode and anode surface that mainly contributed byanion and cation from the remediated soil. In this research, Renggam-Jerangau soil species (HaplicAcrisol + RhodicFerralsol) with a surveymeter reading of 38.0 ± 3.9 μR/hr has been investigation in order to study the mobility of the anion and cation under the influence electric field. Prior to the EK treatment, the elemental composition of the soil and the stainless steel electrode are measured using XRF analyses. Next, the soil sample is remediated at a constant electric potential of 30 V within an hour of treatment period. A surface study for the deposition layer of the cathode and anode using X-ray Photoelectron spectroscopy (XPS) revealed that a narrow photoelectron signal from oxygen O 1s, carbon, C 1s silica, Si 2p, aluminium, Al 2p and chromium, Cr 2p exhibited on the electrode surface and indicate that a different in photoelectron intensity for each element on both electrode surface. In this paper, the mechanism of Si{sup 2+} and Al{sup 2+} cation mobility under the influence of voltage potential between the cathode and anode will be discussed in detail.

  19. Modified surface morphology of a novel Ti-24Nb-4Zr-7.9Sn titanium alloy via anodic oxidation for enhanced interfacial biocompatibility and osseointegration.

    Science.gov (United States)

    Li, Xiang; Chen, Tao; Hu, Jing; Li, Shujun; Zou, Qin; Li, Yunfeng; Jiang, Nan; Li, Hui; Li, Jihua

    2016-08-01

    The Ti-24Nb-4Zr-7.9Sn titanium alloy (Ti2448) has shown potential for use in biomedical implants, because this alloy possesses several important mechanical properties, such as a high fracture strength, low elastic modulus, and good corrosion resistance. In this study, we aimed to produce a hierarchical nanostructure on the surface of Ti2448 to endow this alloy with favorable biological properties. The chemical composition of Ti2448 (64.0wt% Ti, 23.9wt% Nb, 3.9wt% Zr, and 8.1wt% Sn) gives this material electrochemical properties that lead to the generation of topographical features under standard anodic oxidation. We characterized the surface properties of pure Ti (Ti), nanotube-Ti (NT), Ti2448, and nanotube-Ti2448 (NTi2448) based on surface morphology (scanning electron microscopy and atomic force microscopy), chemical and phase compositions (X-ray diffraction and X-ray photoelectron spectroscopy), and wettability (water contact angle). We evaluated the biocompatibility and osteointegration of implant surfaces by observing the behavior of bone marrow stromal cells (BMSCs) cultured on the surfaces in vitro and conducting histological analysis after in vivo implantation of the modified materials. Our results showed that a hierarchical structure with a nanoscale bone-like layer was achieved along with nanotube formation on the Ti2448 surface. The surface characterization data suggested the superior biocompatibility of the NTi2448 surface in comparison with the Ti, NT, and Ti2448 surfaces. Moreover, the NTi2448 surface showed better biocompatibility for BMSCs in vitro and better osteointegration in vivo. Based on these results, we conclude that anodic oxidation facilitated the formation of a nanoscale bone-like structure and nanotubes on Ti2448. Unlike the modified titanium surfaces developed to date, the NTi2448 surface, which presents both mechanical compatibility and bioactivity, offers excellent biocompatibility and osteointegration, suggesting its potential for

  20. Nanotribological properties of precision-controlled regular nanotexture on H-passivated Si surface by current-induced local anodic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Mo Yufei; Zhao Wenjie; Huang Deming; Zhao Fei [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Bai Mingwu [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)], E-mail: mwbai@LZB.ac.cn

    2009-02-15

    Nano-sized textures resulted from localized electrochemical oxidation by using atomic force microscopy (AFM) were fabricated on H-passivated Si surface. In this paper, the fabrication and nanotribological properties of nanotexture by local anodic oxidation (LAO) on H-passivated Si surface are presented. A special attention is paid to find the relation between the size of oxide nanotexture and operational parameters such as tip-sample pulsed bias voltage, pulsewidth, and relative humidity to fabricate oxide nanotexture. The nanotribological properties were investigated by a colloidal probe. The results indicate that the nanotextures exhibited low adhesion and greatly reduced friction force at nanometer scale.

  1. Anodization: a promising nano-modification technique of titanium implants for orthopedic applications.

    Science.gov (United States)

    Yao, Chang; Webster, Thomas J

    2006-01-01

    Anodization is a well-established surface modification technique that produces protective oxide layers on valve metals such as titanium. Many studies have used anodization to produce micro-porous titanium oxide films on implant surfaces for orthopedic applications. An additional hydrothermal treatment has also been used in conjunction with anodization to deposit hydroxyapatite on titanium surfaces; this is in contrast to using traditional plasma spray deposition techniques. Recently, the ability to create nanometer surface structures (e.g., nano-tubular) via anodization of titanium implants in fluorine solutions have intrigued investigators to fabricate nano-scale surface features that mimic the natural bone environment. This paper will present an overview of anodization techniques used to produce micro-porous titanium oxide structures and nano-tubular oxide structures, subsequent properties of these anodized titanium surfaces, and ultimately their in vitro as well as in vivo biological responses pertinent for orthopedic applications. Lastly, this review will emphasize why anodized titanium structures that have nanometer surface features enhance bone forming cell functions.

  2. Surface and interface engineering of anatase TiO2 anode for sodium-ion batteries through Al2O3 surface modification and wise electrolyte selection

    Science.gov (United States)

    Li, Tao; Gulzar, Umair; Bai, Xue; Monaco, Simone; Longoni, Gianluca; Prato, Mirko; Marras, Sergio; Dang, Zhiya; Capiglia, Claudio; Proietti Zaccaria, Remo

    2018-04-01

    In the present study, Al2O3 is utilized for the first time as coating agent on nanostructured anatase TiO2 in order to investigate its effect on sodium-ion batteries performance. Our results show that the Al2O3 coating, introduced by a facile two-step approach, provides beneficial effects to the TiO2-based anodes. However, the coated TiO2 still suffers of capacity fading upon cycling when using 1.0 M of NaClO4 in propylene carbonate (PC) as electrolyte. To address this issue, the influence of different electrolytes (NaClO4 salt in various solvents) is further studied. It is found that the modified TiO2 exhibits significant improvements in cycling performance using binary ethylene carbonate (EC) and PC solvent mixture without the need of the commonly used fluoroethylene carbonate (FEC) additive. Under the best configuration, our battery could deliver a high reversible capacity of 188.1 mAh g-1 at 0.1C after 50 cycles, good rate capability up to 5C, and remarkable long-term cycling stability at 1C rate for 650 cycles. This excellent performance can be ascribed to the synergistic effects of surface and interface engineering enabling the formation of a stable and highly ionic conductive interface layer in EC:PC based electrolyte which combines the native SEI film and an 'artificial' SEI layer of irreversibly formed Na-Al-O.

  3. Low cost UV-Ozone reactor mounted for treatment of electrode anodes used in P-OLEDs devices

    Directory of Open Access Journals (Sweden)

    Emerson Roberto Santos

    Full Text Available Abstract Low cost UV-Ozone reactor using a high pressure mercury vapor lamp of 80 watts without outer bulb showed good results for treatment of ITO films used as anode electrode in the assembly of P-OLED (polymer-organic light emitting diode devices. This study revealed 20 minutes as effective treatment time and it was verified also that the effect of UV-Ozone treatment loses its efficiency as the elapsed time increases. It was analyzed with measurements of contact angle using a droplet of PEDOT:PSS polymer. P-OLEDs devices were mounted with architecture: ITO/PEDOT:PSS/PVK/Alq3/Al. The PVK polymer was diluted in organic solvent of 1,2,4-trichlorobenzene with concentrations of: 5, 10, 20 and 30 mg/mL. Results revealed better performance of P-OLED devices for concentration of 5 mg/mL resulting in lower threshold voltage, elevation of electrical current and similar diode curve.

  4. Effects of Alclad Layer and Anodizing Time on Sulfuric Acid Anodizing and Film Properties of 2E12 Aluminum Alloy

    OpenAIRE

    CHEN Gao-hong; HU Yuan-sen; YU Mei; LIU Jian-hua; LI Guo-ai

    2017-01-01

    Alclad and unclad 2E12 aerospace aluminum alloy were treated by sulfuric acid anodic oxidation. The effects of alclad layer and anodizing time on the anodization behaviour and corrosion resistance of anodic oxide layer on 2E12 aluminum alloy were studied. Surface and cross-section morphology of anodic oxide films were observed by scanning electron microscopy. The electrochemical properties of anodic oxide films were analyzed by potentiodynamic polarization curve and electrochemical impedance ...

  5. Effect of processing on structural features of anodic aluminum oxides

    Science.gov (United States)

    Erdogan, Pembe; Birol, Yucel

    2012-09-01

    Morphological features of the anodic aluminum oxide (AAO) templates fabricated by electrochemical oxidation under different processing conditions were investigated. The selection of the polishing parameters does not appear to be critical as long as the aluminum substrate is polished adequately prior to the anodization process. AAO layers with a highly ordered pore distribution are obtained after anodizing in 0.6 M oxalic acid at 20 °C under 40 V for 5 minutes suggesting that the desired pore features are attained once an oxide layer develops on the surface. While the pore features are not affected much, the thickness of the AAO template increases with increasing anodization treatment time. Pore features are better and the AAO growth rate is higher at 20 °C than at 5 °C; higher under 45 V than under 40 V; higher with 0.6 M than with 0.3 M oxalic acid.

  6. Effect of stacking sequence and surface treatment on the thermal conductivity of multilayered hybrid nano-composites

    Science.gov (United States)

    Papanicolaou, G. C.; Pappa, E. J.; Portan, D. V.; Kotrotsos, A.; Kollia, E.

    2018-02-01

    The aim of the present investigation was to study the effect of both the stacking sequence and surface treatment on the thermal conductivity of multilayered hybrid nano-composites. Four types of multilayered hybrid nanocomposites were manufactured and tested: Nitinol- CNTs (carbon nanotubes)- Acrylic resin; Nitinol- Acrylic resin- CNTs; Surface treated Nitinol- CNTs- Acrylic resin and Surface treated Nitinol- Acrylic resin- CNTs. Surface treatment of Nitinol plies was realized by means of the electrochemical anodization. Surface topography of the anodized nitinol sheets was investigated through Scanning Electron Microscopy (SEM). It was found that the overall thermal response of the manufactured multilayered nano-composites was greatly influenced by both the anodization and the stacking sequence. A theoretical model for the prediction of the overall thermal conductivity has been developed considering the nature of the different layers, their stacking sequence as well as the interfacial thermal resistance. Thermal conductivity and Differential Scanning Calorimetry (DSC) measurements were conducted, to verify the predicted by the model overall thermal conductivities. In all cases, a good agreement between theoretical predictions and experimental results was found.

  7. First principles calculations on the influence of solute elements and chlorine adsorption on the anodic corrosion behavior of Mg (0001) surface

    Science.gov (United States)

    Luo, Zhe; Zhu, Hong; Ying, Tao; Li, Dejiang; Zeng, Xiaoqin

    2018-06-01

    The influences of solute atoms (Li, Al, Mn, Zn, Fe, Ni, Cu, Y, Zr) and Cl adsorption on the anodic corrosion performance on Mg (0001) surface have been investigated based on first-principles calculations, which might be useful for the design of corrosion-resistant Mg alloys. Work function and local electrode potential shift are chosen as descriptors since they quantify the barrier for charge transfer and anodic stability. We found that at 25% surface doping rate, Y decreased the work function of Mg, while the impact of remaining doping elements on the work function of Mg was trivial due to the small surface dipole moment change. The adsorption of Cl destabilized the Mg atoms at surface by weakening the bonding between surface Mg atoms. We find that a stronger hybridization of d orbits of alloying elements (e.g. Zr) with the orbits of Mg can greatly increase the local electrode potential,which even overbalances the negative effect introduced by Cl adsorbates and hence improves the corrosion resistance of Mg alloys.

  8. Advances in surface treatments: Technology, applications, effects

    International Nuclear Information System (INIS)

    Niku-Lari, A.

    1987-01-01

    An international handbook has been produced to include all aspects of residual stresses, including the theoretical background, effects of residual stresses, measurement and calculation and quantitative assessment of residual stress effects. Techniques for altering residual stresses, particularly surface treatments, are discussed. Up to date information on the state of the art is presented. (UK)

  9. Anodization and Optical Appearance of Sputter Deposited Al-Zr Coatings

    DEFF Research Database (Denmark)

    Gudla, Visweswara Chakravarthy; Canulescu, Stela; Shabadi, Rajashekhara

    2014-01-01

    of the anodized layer. The microstructure of the coating is found to influence the appearance of anodized layer owing to the presence of completely or partially dissolved second phases during anodizing process. Oxidation status of the second phase particles in the coatings affected the light absorption......Anodized Al alloy components are extensively used in various applications like architectural, decorative and automobiles for corrosion protection and/or decorative optical appearance. However, tailoring the anodized layer for specific optical appearance is limited due to variation in composition...... and microstructure of the commercial alloys, and even more difficult with recycled alloys. Sputter coating methods promise to control the chemical composition of the Al alloy surfaces and eventually modify the microstructure of the surfaces with heat treatments thus enabling the freedom on the substrate quality...

  10. Porous Co3O4 nanofibers surface-modified by reduced graphene oxide as a durable, high-rate anode for lithium ion battery

    International Nuclear Information System (INIS)

    Hu, Renzong; Zhang, Houpo; Bu, Yunfei; Zhang, Hanyin; Zhao, Bote; Yang, Chenghao

    2017-01-01

    Here we report our findings in synthesis and characterization of porous Co 3 O 4 nanofibers coated with a surface-modification layer, reduced graphene oxide. The unique porous Co 3 O 4 @rGO architecture enables efficient stress relaxation and fast Li + ions and electron transport during discharge/charge cycling. When tested in a half cell, the Co 3 O 4 @rGO electrodes display high Coulombic efficiency, enhanced cyclic stability, and high rate capability (∼900 mAh/g at 1A/g, and ∼600 mAh/g at 5 A/g). The high capacity is contributed by a stable capacity yielded from reversible conversion reactions above 0.8 V vs. Li/Li + , and a increasing capacity induced by the electrolyte decomposition and interfacial storage between 0.8 0.01 V during discahrge. A full cell constructed from a Co 3 O 4 @rGO anode and a LiMn 2 O 4 cathode delivers good capacity retention with operation voltage of ∼2.0 V. These performances are better than those of other full cells using alloy or metal oxide anodes. Our work is a preliminary attempt for practicality of high capacity metal oxide anodes in Li-ion batteries used for the electronic devices.

  11. Enhanced corrosion resistance and biocompatibility of β-type Ti–25Nb–25Zr alloy by electrochemical anodization

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Her-Hsiung [Department of Dentistry, National Yang-Ming University, Taipei, 112 Taiwan (China); Graduate Institute of Basic Medical Science, China Medical University, Taichung, 404 Taiwan (China); Department of Biomedical Informatics, Asia University, Taichung, 413 Taiwan (China); Department of Stomatology, Taipei Veterans General Hospital, Taipei, 112 Taiwan (China); Wu, Chia-Ping; Sun, Ying-Sui; Huang, Hsun-Miao [Institute of Oral Biology, National Yang-Ming University, Taipei, 112 Taiwan (China); Lee, Tzu-Hsin, E-mail: biomaterials@hotmail.com [School of Dentistry, Chung Shan Medical University, Taichung, 402 Taiwan (China); Oral Medicine Center, Chung Shan Medical University Hospital, Taichung, 402 Taiwan (China)

    2013-12-31

    The biocompatibility of implants is largely determined by their surface characteristics. This study presents a novel method for performing electrochemical anodization on β-type Ti–25Nb–25Zr alloy with a low elastic modulus (approximately 70 GPa). This method results in a thin hybrid layer capable of enhancing the surface characteristics of the implants. We investigated the surface topography and microstructure of the resulting Ti–25Nb–25Zr alloy. The corrosion resistance was evaluated using potentiodynamic polarization curve measurements in simulated body fluid. The cytotoxicity was evaluated according to International Organization for Standardization 10993–5 specification. Cell adhesion of human bone marrow mesenchymal stem cells on the test specimens was observed using scanning electron microscopy and fluorescence microscopy. The anodization produced a thin (approximately 40 nm-thick) hybrid oxide layer with a nanoporous outer sublayer (pore size < 15 nm) and a dense inner layer. The thin hybrid oxide layer increased the corrosion resistance of the Ti–25Nb–25Zr alloy by increasing the corrosion potential and decreasing both the corrosion rate and passive current. Ti–25Nb–25Zr alloys with and without anodization treatment were non-toxic. Surface nanotopography on the anodized Ti–25Nb–25Zr alloy enhanced protein adsorption and cell adhesion. Our results demonstrate that electrochemical anodization increases the corrosion resistance and cell adhesion of β-type Ti–25Nb–25Zr alloy while providing a lower elastic modulus suitable for implant applications. - Highlights: • An electrochemical anodization was applied to β-type Ti–25Nb–25Zr alloy surface. • Anodized surface had nanoscale hybrid oxide layer. • Anodized surface increased corrosion resistance due to dense inner sublayer. • Anodized surface enhanced cell adhesion due to nanoporous outer sublayer. • Electrochemical anodization has potential as implant surface treatment.

  12. Enhanced corrosion resistance and biocompatibility of β-type Ti–25Nb–25Zr alloy by electrochemical anodization

    International Nuclear Information System (INIS)

    Huang, Her-Hsiung; Wu, Chia-Ping; Sun, Ying-Sui; Huang, Hsun-Miao; Lee, Tzu-Hsin

    2013-01-01

    The biocompatibility of implants is largely determined by their surface characteristics. This study presents a novel method for performing electrochemical anodization on β-type Ti–25Nb–25Zr alloy with a low elastic modulus (approximately 70 GPa). This method results in a thin hybrid layer capable of enhancing the surface characteristics of the implants. We investigated the surface topography and microstructure of the resulting Ti–25Nb–25Zr alloy. The corrosion resistance was evaluated using potentiodynamic polarization curve measurements in simulated body fluid. The cytotoxicity was evaluated according to International Organization for Standardization 10993–5 specification. Cell adhesion of human bone marrow mesenchymal stem cells on the test specimens was observed using scanning electron microscopy and fluorescence microscopy. The anodization produced a thin (approximately 40 nm-thick) hybrid oxide layer with a nanoporous outer sublayer (pore size < 15 nm) and a dense inner layer. The thin hybrid oxide layer increased the corrosion resistance of the Ti–25Nb–25Zr alloy by increasing the corrosion potential and decreasing both the corrosion rate and passive current. Ti–25Nb–25Zr alloys with and without anodization treatment were non-toxic. Surface nanotopography on the anodized Ti–25Nb–25Zr alloy enhanced protein adsorption and cell adhesion. Our results demonstrate that electrochemical anodization increases the corrosion resistance and cell adhesion of β-type Ti–25Nb–25Zr alloy while providing a lower elastic modulus suitable for implant applications. - Highlights: • An electrochemical anodization was applied to β-type Ti–25Nb–25Zr alloy surface. • Anodized surface had nanoscale hybrid oxide layer. • Anodized surface increased corrosion resistance due to dense inner sublayer. • Anodized surface enhanced cell adhesion due to nanoporous outer sublayer. • Electrochemical anodization has potential as implant surface treatment

  13. Plasma treatment of porous GaAs surface formed by electrochemical etching method: Characterization and properties

    International Nuclear Information System (INIS)

    Naddaf, M.; Saloum, S.

    2008-12-01

    Porous GaAs samples were formed by electrochemical anodic etching of Zn doped p-type GaAs (100) wafers at different etching parameters (time, mode of applied voltage or current and electrolyte). The effect of etching parameters and plasma surface treatment on the optical properties of the prepared sample has been investigated by using room temperature photoluminescence (PL), Raman spectroscopy and reflectance spectroscopic measurements in the range (400-800 nm). The surface morphological changes were studied by using atomic force microscope. It has been found that etching parameters can be controlled to produce a considerably low optical reflectivity porous GaAs layer, attractive for use in solar cells. In addition, it has been observed that the deposition of plasma polymerized HMDSO thin film on porous GaAs surface can be utilized to produce a surface with novel optical properties interesting for solar cells and optoelectronic devices. (author)

  14. Plasma assisted surface treatments of biomaterials.

    Science.gov (United States)

    Minati, L; Migliaresi, C; Lunelli, L; Viero, G; Dalla Serra, M; Speranza, G

    2017-10-01

    The biocompatibility of an implant depends upon the material it is composed of, in addition to the prosthetic device's morphology, mechanical and surface properties. Properties as porosity and pore size should allow, when required, cells penetration and proliferation. Stiffness and strength, that depend on the bulk characteristics of the material, should match the mechanical requirements of the prosthetic applications. Surface properties should allow integration in the surrounding tissues by activating proper communication pathways with the surrounding cells. Bulk and surface properties are not interconnected, and for instance a bone prosthesis could possess the necessary stiffness and strength for the application omitting out prerequisite surface properties essential for the osteointegration. In this case, surface treatment is mandatory and can be accomplished using various techniques such as applying coatings to the prosthesis, ion beams, chemical grafting or modification, low temperature plasma, or a combination of the aforementioned. Low temperature plasma-based techniques have gained increasing consensus for the surface modification of biomaterials for being effective and competitive compared to other ways to introduce surface functionalities. In this paper we review plasma processing techniques and describe potentialities and applications of plasma to tailor the interface of biomaterials. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Improved Interfacial Bonding in Magnesium/Aluminum Overcasting Systems by Aluminum Surface Treatments

    Science.gov (United States)

    Zhang, Hui; Chen, Yiqing; Luo, Alan A.

    2014-12-01

    "Overcasting" technique is used to produce bimetallic magnesium/aluminum (Mg/Al) structures where lightweight Mg can be cast onto solid Al substrates. An inherent difficulty in creating strong Mg/Al interfacial bonding is the natural oxide film on the solid Al surfaces, which reduces the wettability between molten Mg and Al substrates during the casting process. In the paper, an "electropolishing + anodizing" surface treatment has been developed to disrupt the oxide film on a dilute Al-0.08 wt pct Ga alloy, improving the metallurgical bonding between molten Mg and Al substrates in the bimetallic experiments carried out in a high-vacuum test apparatus. The test results provided valuable information of the interfacial phenomena of the Mg/Al bimetallic samples. The results show significantly improved metallurgical bonding in the bimetallic samples with "electropolishing + anodizing" surface treatment and Ga alloying. It is recommended to adjust the pre-heating temperature and time of the Al substrates and the Mg melt temperature to control the interfacial reactions for optimum interfacial properties in the actual overcasting processes.

  16. Laser welding, cutting and surface treatment

    International Nuclear Information System (INIS)

    Crafer, R.C.

    1984-01-01

    Fourteen articles cover a wide range of laser applications in welding, cutting and surface treatment. Future trends are covered as well as specific applications in shipbuilding, the manufacture of heart pacemakers, in the electronics industry, in automobile production and in the aeroengine industry. Safety with industrial lasers and the measurement of laser beam parameters are also included. One article on 'Lasers in the Nuclear Industry' is indexed separately. (U.K.)

  17. Electrochemical treatment of water containing Microcystis aeruginosa in a fixed bed reactor with three-dimensional conductive diamond anodes

    International Nuclear Information System (INIS)

    Mascia, Michele; Monasterio, Sara; Vacca, Annalisa; Palmas, Simonetta

    2016-01-01

    Highlights: • Inactivation of M. aeruginosa was achieved by electrolysis with BDD anodes. • A fixed bed reactor with 3-D electrodes was tested in batch and continuous mode. • The kinetics of the process was determined from batch experiments. • A mathematical model of the process was implemented and validated. • The model was used to predict the system behaviour under different conditions. - Abstract: An electrochemical treatment was investigated to remove Microcystis aeruginosa from water. A fixed bed reactor in flow was tested, which was equipped with electrodes constituted by stacks of grids electrically connected in parallel, with the electric field parallel to the fluid flow. Conductive diamond were used as anodes, platinised Ti as cathode. Electrolyses were performed in continuous and in batch recirculated mode with flow rates corresponding to Re from 10 to 160, current densities in the range 10–60 A m −2 and Cl − concentrations up to 600 g m −3 . The absorbance of chlorophyll-a pigment and the concentration of products and by-products of electrolysis were measured. In continuous experiments without algae in the inlet stream, total oxidants concentrations as equivalent Cl 2 , of about 0.7 g Cl 2 m −3 were measured; the maximum values were obtained at Re = 10 and i = 25 A m −2 , with values strongly dependent on the concentration of Cl − . The highest algae inactivation was obtained under the operative conditions of maximum generation of oxidants; in the presence of microalgae the oxidants concentrations were generally below the detection limit. Results indicated that most of the bulk oxidants electrogenerated is constituted by active chlorine. The prevailing mechanism of M. aeruginosa inactivation is the disinfection by bulk oxidants. The experimental data were quantitatively interpreted through a simple plug flow model, in which the axial dispersion accounts for the non-ideal flow behaviour of the system; the model was successfully

  18. Electrochemical treatment of water containing Microcystis aeruginosa in a fixed bed reactor with three-dimensional conductive diamond anodes

    Energy Technology Data Exchange (ETDEWEB)

    Mascia, Michele, E-mail: michele.mascia@unica.it; Monasterio, Sara; Vacca, Annalisa; Palmas, Simonetta

    2016-12-05

    Highlights: • Inactivation of M. aeruginosa was achieved by electrolysis with BDD anodes. • A fixed bed reactor with 3-D electrodes was tested in batch and continuous mode. • The kinetics of the process was determined from batch experiments. • A mathematical model of the process was implemented and validated. • The model was used to predict the system behaviour under different conditions. - Abstract: An electrochemical treatment was investigated to remove Microcystis aeruginosa from water. A fixed bed reactor in flow was tested, which was equipped with electrodes constituted by stacks of grids electrically connected in parallel, with the electric field parallel to the fluid flow. Conductive diamond were used as anodes, platinised Ti as cathode. Electrolyses were performed in continuous and in batch recirculated mode with flow rates corresponding to Re from 10 to 160, current densities in the range 10–60 A m{sup −2} and Cl{sup −} concentrations up to 600 g m{sup −3}. The absorbance of chlorophyll-a pigment and the concentration of products and by-products of electrolysis were measured. In continuous experiments without algae in the inlet stream, total oxidants concentrations as equivalent Cl{sub 2}, of about 0.7 g Cl{sub 2} m{sup −3} were measured; the maximum values were obtained at Re = 10 and i = 25 A m{sup −2}, with values strongly dependent on the concentration of Cl{sup −}. The highest algae inactivation was obtained under the operative conditions of maximum generation of oxidants; in the presence of microalgae the oxidants concentrations were generally below the detection limit. Results indicated that most of the bulk oxidants electrogenerated is constituted by active chlorine. The prevailing mechanism of M. aeruginosa inactivation is the disinfection by bulk oxidants. The experimental data were quantitatively interpreted through a simple plug flow model, in which the axial dispersion accounts for the non-ideal flow behaviour of the

  19. Final Report: Rational Design of Anode Surface Chemistry in Microbial Fuel Cells for Improved Exoelectrogen Attachment and Electron Transfer

    Science.gov (United States)

    2015-12-21

    characteristics to show that cathodes with largest amounts of carbon oxides and larger pores tended to have the best performance. Non-Pt group metals were... cathodes have a higher amount of oxidized tetrafluoroethylene with higher overall roughness, high similarity, and mesocale pores (10 nm – 1 um). With the...with more in preparation. In this project period we applied electrochemical oxidation of activated carbon anodes to demonstrate that increasing

  20. Self-ordering anodized nanotubes: Enhancing the performance by surface plasmon for dye-sensitized solar cell

    International Nuclear Information System (INIS)

    Agarwala, S.; Ho, G.W.

    2012-01-01

    In the present work, electrochemical anodization has been used to prepare uniform TiO 2 nanotube array photoelectrode. The average internal diameter, tube length and wall thickness of the optimized morphology is ∼180 nm, 14 μm and 10 nm, respectively. It was found that the tube diameter increases with the anodization voltage. Diffraction data reveals that the nanotubes consist solely of anatase phase. Back illuminated geometry of dye-sensitized solar cell (DSSC), with nanotubes grown at 60 V for 2 h, gave a cell performance of 4.5%. TiO 2 nanotubes are loaded with silver (Ag) nanoparticles synthesized by a hydrothermal route. The Ag particle size is controlled resulting in solar conversion efficiency to increase by 22%. The DSSC based on TiO 2 nanotube with Ag nanoparticles shows power conversion efficiency of 5.5%. Detailed characterization are performed, presented and discussed. - Graphical abstract: Enhanced solar conversion efficiency of dye-sensitized solar cells by decorating TiO 2 nanotube array with Ag nanoparticles. Highlights: ► Uniform array of TiO 2 nanotubes synthesized via electrochemical anodization. ► Back illuminated DSSC gave a cell performance of 4.5%. ► TiO 2 nanotubes are loaded with Ag nanoparticles, which increased the power conversion efficiency to 5.5%.

  1. Self-ordering anodized nanotubes: Enhancing the performance by surface plasmon for dye-sensitized solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Agarwala, S., E-mail: agarwala.shweta@gmail.com [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive, Singapore 117576 (Singapore); Ho, G.W. [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive, Singapore 117576 (Singapore)

    2012-05-15

    In the present work, electrochemical anodization has been used to prepare uniform TiO{sub 2} nanotube array photoelectrode. The average internal diameter, tube length and wall thickness of the optimized morphology is {approx}180 nm, 14 {mu}m and 10 nm, respectively. It was found that the tube diameter increases with the anodization voltage. Diffraction data reveals that the nanotubes consist solely of anatase phase. Back illuminated geometry of dye-sensitized solar cell (DSSC), with nanotubes grown at 60 V for 2 h, gave a cell performance of 4.5%. TiO{sub 2} nanotubes are loaded with silver (Ag) nanoparticles synthesized by a hydrothermal route. The Ag particle size is controlled resulting in solar conversion efficiency to increase by 22%. The DSSC based on TiO{sub 2} nanotube with Ag nanoparticles shows power conversion efficiency of 5.5%. Detailed characterization are performed, presented and discussed. - Graphical abstract: Enhanced solar conversion efficiency of dye-sensitized solar cells by decorating TiO{sub 2} nanotube array with Ag nanoparticles. Highlights: Black-Right-Pointing-Pointer Uniform array of TiO{sub 2} nanotubes synthesized via electrochemical anodization. Black-Right-Pointing-Pointer Back illuminated DSSC gave a cell performance of 4.5%. Black-Right-Pointing-Pointer TiO{sub 2} nanotubes are loaded with Ag nanoparticles, which increased the power conversion efficiency to 5.5%.

  2. Influence of surface coating on structure and properties of metallic lithium anode for rechargeable Li-O2 battery

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Q.; Wang, Q.; Ma, Q.; Song, Q.; Chen, Q.

    2017-07-01

    Amorphous lithium phosphorous oxynitride film was coated directly on pre-treated lithium metal as anode of lithium air battery by radio-frequency sputtering technique from a Li3PO4 target. The structure and composition of modified anode was analyzed before and after charge/discharge test in a lithium-air battery, which comprises 0.5M LiNO3/TEGDME as the electrolyte and super P carbon as cathode. Batteries were galvanostatically discharged by an Arbin BT-2000 battery tester between open current voltage and 2.15V vs. Li+/Li at various current regimes ranging from 0.1–0.4mA/cm2. Compared with fresh lithium, LIPON-coated anode exhibited better electrochemical performance. Good charging efficiency of 90% at a narrower voltage gap with high ionic conductivity of 9.4×10−5S/cm was achieved through optimizing lithium pre-treated conditions, sputtering N2 flows and suitable solute for electrolyte. (Author)

  3. Waste water treatment in surface mines

    Energy Technology Data Exchange (ETDEWEB)

    Navasardyants, M A; Esipov, V Z; Ryzhkov, Yu A

    1981-01-01

    This paper evaluates problems associated with waste water from coal surface mines of the Kemerovougol' association in the Kuzbass. Waste water treatment in the Kuzbass is of major importance as the region is supplied with water from only one river, the Tom river. Water influx to Kemerovougol' surface mines in a year amounts to 136 million m/sup 3/. The water is used during technological processes, for fire fighting, and spraying to prevent dusting; the rest, about 82.1 million m/sup 3/, is discharged into surface waters. Of this amount, 25.1 million m/sup 3/ is heavily polluted water, 46.6 million m3 are polluted but within limits, and 10.4 million m/sup 3/ are characterized as relatively clean. Waste water is polluted with: suspended matters, oils and oil products, nitrates, nitrides and chlorides. Suspended matter content sometimes reaches 4,000 and 5,000 mg/l, and oil product content in water amounts to 2.17 mg/l. Water treatment in surface mines is two-staged: sumps and sedimentation tanks are used. Water with suspended matter content of 50 to 100 mg/l in winter and summer, and 200 to 250 mg/l in spring and autumn is reduced in sumps to 25 to 30 mg/l in summer and winter and to 40 to 50 mg/l in autumn and spring. During the first stage water treatment efficiency ranges from 50 to 80%. During the second stage water is collected in sedimentation tanks. It is noted that so-called secondary pollution is one of the causes of the relatively high level of suspended matter in discharged water. Water discharged from sedimentation tanks carries clay and loam particles from the bottom and walls of water tanks and channels.

  4. Synthesis of calcium-phosphorous doped TiO2 nanotubes by anodization and reverse polarization: A promising strategy for an efficient biofunctional implant surface

    International Nuclear Information System (INIS)

    Alves, Sofia A.; Patel, Sweetu B.; Sukotjo, Cortino; Mathew, Mathew T.; Filho, Paulo N.; Celis, Jean-Pierre

    2017-01-01

    Highlights: • A new surface modification methodology for bio-functionalization of TiO2 NTs is addressed • Bone-like structured TiO2 nanotubular surfaces containing Ca and P were synthesized. • Ca/P-doped TiO2 NTs enhanced adhesion and proliferation of osteoblastic-like cells. • The bio-functionalization granted improved bio-electrochemical stability to TiO2 NTs. - Abstract: The modification of surface features such as nano-morphology/topography and chemistry have been employed in the attempt to design titanium oxide surfaces able to overcome the current dental implants failures. The main goal of this study is the synthesis of bone-like structured titanium dioxide (TiO 2 ) nanotubes enriched with Calcium (Ca) and Phosphorous (P) able to enhance osteoblastic cell functions and, simultaneously, display an improved corrosion behavior. To achieve the main goal, TiO 2 nanotubes were synthetized and doped with Ca and P by means of a novel methodology which relied, firstly, on the synthesis of TiO 2 nanotubes by anodization of titanium in an organic electrolyte followed by reverse polarization and/or anodization, in an aqueous electrolyte. Results show that hydrophilic bone-like structured TiO 2 nanotubes were successfully synthesized presenting a highly ordered nano-morphology characterized by non-uniform diameters. The chemical analysis of such nanotubes confirmed the presence of CaCO 3 , Ca 3 (PO 4 ) 2 , CaHPO 4 and CaO compounds. The nanotube surfaces submitted to reverse polarization, presented an improved cell adhesion and proliferation compared to smooth titanium. Furthermore, these surfaces displayed a significantly lower passive current in artificial saliva, and so, potential to minimize their bio-degradation through corrosion processes. This study addresses a very simple and promising multidisciplinary approach bringing new insights for the development of novel methodologies to improve the outcome of osseointegrated implants.

  5. Forming lead-based anodes

    Energy Technology Data Exchange (ETDEWEB)

    Ogorodnichuk, V I; Voitsekhovich, R I

    1972-01-01

    Lead-based anodes can be produced by forming a layer of lead dioxide by chemical treatment in a solution of sulfuric acid in potassium permanganate at 80 to 100/sup 0/. The solution is mixed by compressed air. (RWR)

  6. Solvent anode for plutonium purification

    International Nuclear Information System (INIS)

    Bowersox, D.F.; Fife, K.W.; Christensen, D.C.

    1986-01-01

    The purpose of this study is to develop a technique to allow complete oxidation of plutonium from the anode during plutonium electrorefining. This will eliminate the generation of a ''spent'' anode heel which requires further treatment for recovery. Our approach is to employ a solvent metal in the anode to provide a liquid anode pool throughout electrorefining. We use molten salts and metals in ceramic crucibles at 700 0 C. Our goal is to produce plutonium metal at 99.9% purity with oxidation and transfer of more than 98% of the impure plutonium feed metal from the anode into the salt and product phases. We have met these criteria in experiments on the 100 to 1000 g scale. We plan to scale our operations to 4 kg of feed plutonium and to optimize the process parameters

  7. Fabrication of porous anodic alumina films by using two-step anodization process

    International Nuclear Information System (INIS)

    Xu Zhan; Zhou Bin; Xu Xiang; Wang Xiaoli; Wu Di; Shen Jun

    2006-01-01

    This article introduces the fabrication of the porous anodic alumina films which have ordered pore arrangement by using a two-step anodization process. The films have a parallel channel structure which nanopore diameter can be 20-100 nm, and depth can reach 50 μm. The change of pore structure in the first and second anodization, moving the alumina layer, widening process was analysed. The effect of the parameters such as different electrolytes, anodization temperature and the voltage on the nanopore structure was studied. The surface and profile structure through FE-SEM (field emission scanning electron microscope), the element composition in tiny area of the anodic aluminum oxide (AAO) surface were studied. The result indicates the pore diameter of AAO which is anodized in oxalic acid solution is larger than which anodized in sulfuric acid solution. The anodization temperature and voltage can enlarge the nanopore diameter of AAO in a range. (authors)

  8. Preparation and electrochemical properties of nanocable-like Nb2O5/surface-modified carbon nanotubes composites for anode materials in lithium ion batteries

    International Nuclear Information System (INIS)

    Shi, Chongfu; Xiang, Kaixiong; Zhu, Yirong; Chen, Xianhong; Zhou, Wei; Chen, Han

    2017-01-01

    Highlights: •The acid pretreatment for CNTs is a key factor to fabricate nanocable-like Nb 2 O 5 /SMCNTs composites. •The polar functional groups can induce the symmetrical growth of Nb 2 O 5 nanoparticitles on the surface of SMCNTs. •SMCNTs can provide sufficient conductive contacts for composites and abundant active sites for electrochemical reaction. -- Abstract: Uniform nanocable-like Nb 2 O 5 /surface-modified carbon nanotubes (SMCNTs) composites for anode materials in lithium ion batteries were synthesized by hydrothermal method. It was indicated that Nb 2 O 5 nanoparticles were tightly and uniformly cultivated on carbon nanotubes when CNTs were pretreated with concentrated H 2 SO 4 . As a result, Nb 2 O 5 /SMCNTs composite materials showed remarkable electrochemical performance as anode materials for lithium-ion batteries. It delivered a high reversible capacity of 441 mA h g −1 cycled at the current density of 40 mA g −1 after 100 cycles and an excellent rate capacity of 185 mA h g −1 at the high current density of 5000 mA g −1 after 200 cycles.

  9. Ultra-High Density Single Nanometer-Scale Anodic Alumina Nanofibers Fabricated by Pyrophosphoric Acid Anodizing

    Science.gov (United States)

    Kikuchi, Tatsuya; Nishinaga, Osamu; Nakajima, Daiki; Kawashima, Jun; Natsui, Shungo; Sakaguchi, Norihito; Suzuki, Ryosuke O.

    2014-12-01

    Anodic oxide fabricated by anodizing has been widely used for nanostructural engineering, but the nanomorphology is limited to only two oxides: anodic barrier and porous oxides. Therefore, the discovery of an additional anodic oxide with a unique nanofeature would expand the applicability of anodizing. Here we demonstrate the fabrication of a third-generation anodic oxide, specifically, anodic alumina nanofibers, by anodizing in a new electrolyte, pyrophosphoric acid. Ultra-high density single nanometer-scale anodic alumina nanofibers (1010 nanofibers/cm2) consisting of an amorphous, pure aluminum oxide were successfully fabricated via pyrophosphoric acid anodizing. The nanomorphologies of the anodic nanofibers can be controlled by the electrochemical conditions. Anodic tungsten oxide nanofibers can also be fabricated by pyrophosphoric acid anodizing. The aluminum surface covered by the anodic alumina nanofibers exhibited ultra-fast superhydrophilic behavior, with a contact angle of less than 1°, within 1 second. Such ultra-narrow nanofibers can be used for various nanoapplications including catalysts, wettability control, and electronic devices.

  10. Growth of porous anodized alumina on the sputtered aluminum films with 2D-3D morphology for high specific surface area

    Science.gov (United States)

    Liao, M. W.; Chung, C. K.

    2014-08-01

    The porous anodic aluminum oxide (AAO) with high-aspect-ratio pore channels is widely used as a template for fabricating nanowires or other one-dimensional (1D) nanostructures. The high specific surface area of AAO can also be applied to the super capacitor and the supporting substrate for catalysis. The rough surface could be helpful to enhance specific surface area but it generally results in electrical field concentration even to ruin AAO. In this article, the aluminum (Al) films with the varied 2D-3D morphology on Si substrates were prepared using magnetron sputtering at a power of 50 W-185 W for 1 h at a working pressure of 2.5 × 10-1 Pa. Then, AAO was fabricated from the different Al films by means of one-step hybrid pulse anodizing (HPA) between the positive 40 V and the negative -2 V (1 s:1 s) for 3 min in 0.3 M oxalic acid at a room temperature. The microstructure and morphology of Al films were characterized by X-ray diffraction, scanning electron microscope and atomic force microscope, respectively. Some hillocks formed at the high target power could be attributed to the grain texture growth in the normal orientation of Al(1 1 1). The 3D porous AAO structure which is different from the conventional 2D planar one has been successfully demonstrated using HPA on the film with greatly rough hillock-surface formed at the highest power of 185 W. It offers a potential application of the new 3D AAO to high specific surface area devices.

  11. Growth of porous anodized alumina on the sputtered aluminum films with 2D–3D morphology for high specific surface area

    Energy Technology Data Exchange (ETDEWEB)

    Liao, M.W.; Chung, C.K., E-mail: ckchung@mail.ncku.edu.tw

    2014-08-01

    The porous anodic aluminum oxide (AAO) with high-aspect-ratio pore channels is widely used as a template for fabricating nanowires or other one-dimensional (1D) nanostructures. The high specific surface area of AAO can also be applied to the super capacitor and the supporting substrate for catalysis. The rough surface could be helpful to enhance specific surface area but it generally results in electrical field concentration even to ruin AAO. In this article, the aluminum (Al) films with the varied 2D–3D morphology on Si substrates were prepared using magnetron sputtering at a power of 50 W–185 W for 1 h at a working pressure of 2.5 × 10⁻¹ Pa. Then, AAO was fabricated from the different Al films by means of one-step hybrid pulse anodizing (HPA) between the positive 40 V and the negative -2 V (1 s:1 s) for 3 min in 0.3 M oxalic acid at a room temperature. The microstructure and morphology of Al films were characterized by X-ray diffraction, scanning electron microscope and atomic force microscope, respectively. Some hillocks formed at the high target power could be attributed to the grain texture growth in the normal orientation of Al(1 1 1). The 3D porous AAO structure which is different from the conventional 2D planar one has been successfully demonstrated using HPA on the film with greatly rough hillock-surface formed at the highest power of 185 W. It offers a potential application of the new 3D AAO to high specific surface area devices.

  12. Anode Fall Formation in a Hall Thruster

    International Nuclear Information System (INIS)

    Dorf, Leonid A.; Raitses, Yevgeny F.; Smirnov, Artem N.; Fisch, Nathaniel J.

    2004-01-01

    As was reported in our previous work, accurate, nondisturbing near-anode measurements of the plasma density, electron temperature, and plasma potential performed with biased and emissive probes allowed the first experimental identification of both electron-repelling (negative anode fall) and electron-attracting (positive anode fall) anode sheaths in Hall thrusters. An interesting new phenomenon revealed by the probe measurements is that the anode fall changes from positive to negative upon removal of the dielectric coating, which appears on the anode surface during the course of Hall thruster operation. As reported in the present work, energy dispersion spectroscopy analysis of the chemical composition of the anode dielectric coating indicates that the coating layer consists essentially of an oxide of the anode material (stainless steel). However, it is still unclear how oxygen gets into the thruster channel. Most importantly, possible mechanisms of anode fall formation in a Hall thruster with a clean and a coated anodes are analyzed in this work; practical implication of understanding the general structure of the electron-attracting anode sheath in the case of a coated anode is also discussed

  13. Anodized Steel Electrodes for Supercapacitors.

    Science.gov (United States)

    Sagu, Jagdeep S; Wijayantha, K G Upul; Bohm, Mallika; Bohm, Siva; Kumar Rout, Tapan

    2016-03-09

    Steel was anodized in 10 M NaOH to enhance its surface texture and internal surface area for application as an electrode in supercapacitors. A mechanism was proposed for the anodization process. Field-emission gun scanning electron microscopy (FEGSEM) studies of anodized steel revealed that it contains a highly porous sponge like structure ideal for supercapacitor electrodes. X-ray photoelectron spectroscopy (XPS) measurements showed that the surface of the anodized steel was Fe2O3, whereas X-ray diffraction (XRD) measurements indicated that the bulk remained as metallic Fe. The supercapacitor performance of the anodized steel was tested in 1 M NaOH and a capacitance of 18 mF cm(-2) was obtained. Cyclic voltammetry measurements showed that there was a large psueudocapacitive contribution which was due to oxidation of Fe to Fe(OH)2 and then further oxidation to FeOOH, and the respective reduction of these species back to metallic Fe. These redox processes were found to be remarkably reversible as the electrode showed no loss in capacitance after 10000 cycles. The results demonstrate that anodization of steel is a suitable method to produce high-surface-area electrodes for supercapacitors with excellent cycling lifetime.

  14. Surfactant-assisted sol gel preparation of high-surface area mesoporous TiO2 nanocrystalline Li-ion battery anodes

    International Nuclear Information System (INIS)

    Casino, S.; Di Lupo, F.; Francia, C.; Tuel, A.; Bodoardo, S.; Gerbaldi, C.

    2014-01-01

    Highlights: • Mesoporous TiO 2 nanocrystalline lithium battery anodes with tunable morphology. • Simple sol–gel technique using different cationic surfactants is adopted. • Textural/morphological characteristics define the electrochemical behaviour. • TiO 2 anatase using C16TAB exhibits stable performance after 200 cycles. • It shows promising prospects as high-voltage safe Li-ion battery anode. - Abstract: We here investigate the physico-chemical/morphological characteristics and cycling behaviour of several kinds of nanocrystalline TiO 2 Li-ion battery anodes selectively prepared through a simple sol–gel strategy based on a low-cost titanium oxysulfate precursor, by mediation of different cationic surfactants having different features (e.g., chain lengths, counter ion, etc.): i.e., cetyl-trimethylammonium bromide (CTAB), cetyl-trimethylammonium chloride (CTAC), benzalkonium chloride (BC) or octadecyl-trimethyl ammonium bromide (C 18 TAB). X-ray diffraction profiles reveal single phase anatase having good correspondence with the reference pattern when using short chain CTAB, while in the other cases the presence of chloride and/or an increased chain length affect the purity of the samples. FESEM analysis reveal nanosized particles forming cauliflower-like aggregates. TiO 2 materials demonstrate mesoporous characteristics and large specific surface area ranging from 250 to 30 m 2 g −1 . Remarkably stable electrode performance are achieved by appropriately selecting the cationic surfactant and the surfactant/precursor ratio. Detailed analysis is provided on the effect of the reaction conditions upon the formation of mesoporous crystalline titania enlightening new directions for the development of high performing lithium storage electrodes by a simple and low cost sol–gel strategy

  15. Surfactant-assisted sol gel preparation of high-surface area mesoporous TiO{sub 2} nanocrystalline Li-ion battery anodes

    Energy Technology Data Exchange (ETDEWEB)

    Casino, S. [GAME Lab, Department of Applied Science and Technology – DISAT, Institute of Chemistry, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino (Italy); Di Lupo, F., E-mail: francesca.dilupo@polito.it [GAME Lab, Department of Applied Science and Technology – DISAT, Institute of Chemistry, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino (Italy); Francia, C. [GAME Lab, Department of Applied Science and Technology – DISAT, Institute of Chemistry, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino (Italy); Tuel, A. [IRCELYON, Institut de Recherches sur la Catalyse et l’environnement de Lyon, UMR 5256, CNRS-Université de Lyon 1, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex (France); Bodoardo, S. [GAME Lab, Department of Applied Science and Technology – DISAT, Institute of Chemistry, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino (Italy); Gerbaldi, C., E-mail: claudio.gerbaldi@polito.it [GAME Lab, Department of Applied Science and Technology – DISAT, Institute of Chemistry, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino (Italy)

    2014-05-01

    Highlights: • Mesoporous TiO{sub 2} nanocrystalline lithium battery anodes with tunable morphology. • Simple sol–gel technique using different cationic surfactants is adopted. • Textural/morphological characteristics define the electrochemical behaviour. • TiO{sub 2} anatase using C16TAB exhibits stable performance after 200 cycles. • It shows promising prospects as high-voltage safe Li-ion battery anode. - Abstract: We here investigate the physico-chemical/morphological characteristics and cycling behaviour of several kinds of nanocrystalline TiO{sub 2} Li-ion battery anodes selectively prepared through a simple sol–gel strategy based on a low-cost titanium oxysulfate precursor, by mediation of different cationic surfactants having different features (e.g., chain lengths, counter ion, etc.): i.e., cetyl-trimethylammonium bromide (CTAB), cetyl-trimethylammonium chloride (CTAC), benzalkonium chloride (BC) or octadecyl-trimethyl ammonium bromide (C{sub 18}TAB). X-ray diffraction profiles reveal single phase anatase having good correspondence with the reference pattern when using short chain CTAB, while in the other cases the presence of chloride and/or an increased chain length affect the purity of the samples. FESEM analysis reveal nanosized particles forming cauliflower-like aggregates. TiO{sub 2} materials demonstrate mesoporous characteristics and large specific surface area ranging from 250 to 30 m{sup 2} g{sup −1}. Remarkably stable electrode performance are achieved by appropriately selecting the cationic surfactant and the surfactant/precursor ratio. Detailed analysis is provided on the effect of the reaction conditions upon the formation of mesoporous crystalline titania enlightening new directions for the development of high performing lithium storage electrodes by a simple and low cost sol–gel strategy.

  16. Electrochemical treatment of water containing Microcystis aeruginosa in a fixed bed reactor with three-dimensional conductive diamond anodes.

    Science.gov (United States)

    Mascia, Michele; Monasterio, Sara; Vacca, Annalisa; Palmas, Simonetta

    2016-12-05

    An electrochemical treatment was investigated to remove Microcystis aeruginosa from water. A fixed bed reactor in flow was tested, which was equipped with electrodes constituted by stacks of grids electrically connected in parallel, with the electric field parallel to the fluid flow. Conductive diamond were used as anodes, platinised Ti as cathode. Electrolyses were performed in continuous and in batch recirculated mode with flow rates corresponding to Re from 10 to 160, current densities in the range 10-60Am(-2) and Cl(-) concentrations up to 600gm(-3). The absorbance of chlorophyll-a pigment and the concentration of products and by-products of electrolysis were measured. In continuous experiments without algae in the inlet stream, total oxidants concentrations as equivalent Cl2, of about 0.7gCl2m(-3) were measured; the maximum values were obtained at Re=10 and i=25Am(-2), with values strongly dependent on the concentration of Cl(-). The highest algae inactivation was obtained under the operative conditions of maximum generation of oxidants; in the presence of microalgae the oxidants concentrations were generally below the detection limit. Results indicated that most of the bulk oxidants electrogenerated is constituted by active chlorine. The prevailing mechanism of M. aeruginosa inactivation is the disinfection by bulk oxidants. The experimental data were quantitatively interpreted through a simple plug flow model, in which the axial dispersion accounts for the non-ideal flow behaviour of the system; the model was successfully used to simulate the performances of the reactor in the single-stack configuration used for the experiments and in multi-stack configurations. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Effect of nanoporous TiO2 coating and anodized Ca2+ modification of titanium surfaces on early microbial biofilm formation

    Directory of Open Access Journals (Sweden)

    Wennerberg Ann

    2011-03-01

    Full Text Available Abstract Background The soft tissue around dental implants forms a barrier between the oral environment and the peri-implant bone and a crucial factor for long-term success of therapy is development of a good abutment/soft-tissue seal. Sol-gel derived nanoporous TiO2 coatings have been shown to enhance soft-tissue attachment but their effect on adhesion and biofilm formation by oral bacteria is unknown. Methods We have investigated how the properties of surfaces that may be used on abutments: turned titanium, sol-gel nanoporous TiO2 coated surfaces and anodized Ca2+ modified surfaces, affect biofilm formation by two early colonizers of the oral cavity: Streptococcus sanguinis and Actinomyces naeslundii. The bacteria were detected using 16S rRNA fluorescence in situ hybridization together with confocal laser scanning microscopy. Results Interferometry and atomic force microscopy revealed all the surfaces to be smooth (Sa ≤ 0.22 μm. Incubation with a consortium of S. sanguinis and A. naeslundii showed no differences in adhesion between the surfaces over 2 hours. After 14 hours, the level of biofilm growth was low and again, no differences between the surfaces were seen. The presence of saliva increased the biofilm biovolume of S. sanguinis and A. naeslundii ten-fold compared to when saliva was absent and this was due to increased adhesion rather than biofilm growth. Conclusions Nano-topographical modification of smooth titanium surfaces had no effect on adhesion or early biofilm formation by S. sanguinis and A. naeslundii as compared to turned surfaces or those treated with anodic oxidation in the presence of Ca2+. The presence of saliva led to a significantly greater biofilm biovolume but no significant differences were seen between the test surfaces. These data thus suggest that modification with sol-gel derived nanoporous TiO2, which has been shown to improve osseointegration and soft-tissue healing in vivo, does not cause greater biofilm

  18. Effect of Anode Dielectric Coating on Hall Thruster Operation

    International Nuclear Information System (INIS)

    Dorf, L.; Raitses, Y.; Fisch, N.J.; Semenov, V.

    2003-01-01

    An interesting phenomenon observed in the near-anode region of a Hall thruster is that the anode fall changes from positive to negative upon removal of the dielectric coating, which is produced on the anode surface during the normal course of Hall thruster operation. The anode fall might affect the thruster lifetime and acceleration efficiency. The effect of the anode coating on the anode fall is studied experimentally using both biased and emissive probes. Measurements of discharge current oscillations indicate that thruster operation is more stable with the coated anode

  19. Uniform superhydrophobic surfaces using micro/nano complex structures formed spontaneously by a simple and cost-effective nonlithographic process based on anodic aluminum oxide technology

    International Nuclear Information System (INIS)

    Kim, Dae-Ho; Cho, Chae-Ryong; Kim, Jong-Man; Kim, Yongsung; Kim, Byung Min; Ko, Jong Soo

    2011-01-01

    This paper presents a uniform micro/nano double-roughened superhydrophobic surface with a high static contact angle (CA) and low contact angle hysteresis (CAH). The proposed micro/nano complex structured surfaces were self-fabricated simply and efficiently using a very simple and low-cost nonlithographic sequential process, which consists of aluminum (Al) sputtering, anodization of the Al layer and pore widening, without specific equipment and additional subsequent processes. The wetting properties of the fabricated surfaces were characterized by measuring the static CAs and the CAHs after plasma polymerized fluorocarbon coating with a low surface energy. The measured static CA and CAH were 154 ± 2.3° and 5.7 ± 0.8°, respectively, showing that the fabricated double-roughened surfaces exhibit superhydrophobic behaviors clearly. In addition, the proposed double-scaled surfaces at a wafer-level exhibited uniform superhydrophobic behaviors across the wafer with an apparent CA and CAH of 153.9 ± 0.8° and 4.9 ± 1.3°, respectively.

  20. Erosion resistance comparison of alternative surface treatments

    Science.gov (United States)

    Česánek, Z.; Schubert, J.; Houdková, Š.

    2017-05-01

    Erosion is a process characterized by the particle separation and the damage of component functional surfaces. Thermal spraying technology HP/HVOF (High Pressure / High Velocity Oxygen Fuel) is commonly used for protection of component surfaces against erosive wear. Alloy as well as cermet based coatings meet the requirements for high erosion resistance. Wear resistance is in many cases the determining property of required component functioning. The application suitability of coating materials is particularly influenced by different hardness. This paper therefore presents an erosion resistance comparison of alloy and cermet based coatings. The coatings were applied on steel substrates and were subjected to the erosive test using the device for evaluation of material erosion resistance working on the principle of centrifugal erodent flow. Abrasive sand Al2O3 with grain size 212-250 μm was selected as an erosive material. For this purpose, the specimens were prepared by thermal spraying technology HP/HVOF using commercially available powders Stellite 6, NiCrBSi, Cr3C2-25%NiCr, Cr3C2-25%CoNiCrAlY, Hastelloy C-276 and experimental coating TiMoCN-29% Ni. Erosion resistance of evaluated coatings was compared with erosive resistance of 1.4923 high alloyed steel without nitridation and in nitrided state and further with surface treatment using technology PVD. According to the evaluation, the resulting erosive resistance depends not only on the selected erodent and surface protection, but also on the erodent impact angle.

  1. The surface evolution of La0.4Sr0.6TiO3+δ anode in solid oxide fuel cells: Understanding the sulfur-promotion effect

    Science.gov (United States)

    Yan, Ning; Zanna, Sandrine; Klein, Lorena H.; Roushanafshar, Milad; Amirkhiz, Babak S.; Zeng, Yimin; Rothenberg, Gadi; Marcus, Philippe; Luo, Jing-Li

    2017-03-01

    The ideal solid oxide fuel cells (SOFCs) can be powered by readily available hydrocarbon fuels containing impurities. While this is commonly recognized as a key advantage of SOFC, it also, together with the elevated operating temperature, becomes the main barrier impeding the in-situ or operando investigations of the anode surface chemistry. Here, using a well-designed quenching experiment, we managed to characterize the near-surface structure of La0.4Sr0.6TiO3+δ (LST) anode in SOFCs fuelled by H2S-containing methane. This new method enabled us to clearly observe the surface amorphization and sulfidation of LST under simulated SOFC operating conditions. The ∼1 nm-thick two dimensional sulfur-adsorbed layer was on top of the disordered LST, containing -S, -SH and elemental sulfur species. In SOFC test, such "poisoned" anode showed increased performances: a ten-fold enhanced power density enhancement (up to 30 mW cm-2) and an improved open circuit voltage (from 0.69 V to 1.17 V). Moreover, its anodic polarization resistance in methane decreased to 21.53 Ω cm2, a difference of 95% compared with the sulfur-free anode. Control experiments confirmed that once the adsorbed sulfur species were removed electrochemically, methane conversion slowed down simultaneously till full stop.

  2. Mechanical polishing as an improved surface treatment for platinum screen-printed electrodes

    Directory of Open Access Journals (Sweden)

    Junqiao Lee

    2016-07-01

    Full Text Available The viability of mechanical polishing as a surface pre-treatment method for commercially available platinum screen-printed electrodes (SPEs was investigated and compared to a range of other pre-treatment methods (UV-Ozone treatment, soaking in N,N-dimethylformamide, soaking and anodizing in aqueous NaOH solution, and ultrasonication in tetrahydrofuran. Conventional electrochemical activation of platinum SPEs in 0.5 M H2SO4 solution was ineffective for the removal of contaminants found to be passivating the screen-printed surfaces. However, mechanical polishing showed a significant improvement in hydrogen adsorption and in electrochemically active surface areas (probed by two different redox couples due to the effective removal of surface contaminants. Results are also presented that suggest that SPEs are highly susceptible to degradation by strong acidic or caustic solutions, and could potentially lead to instability in long-term applications due to continual etching of the binding materials. The ability of SPEs to be polished effectively extends the reusability of these traditionally “single-use” devices. Keywords: Screen-printed electrodes, Polishing, Platinum, Activation, Pre-treatment, Cyclic voltammetry

  3. Influence of surface treatment on the biocompatibility of aluminum substrates promising for medical application

    Energy Technology Data Exchange (ETDEWEB)

    Kiradzhiyska, D. D., E-mail: denica.kiradjiiska@gmail.com; Mantcheva, R. D., E-mail: r-manch@abv.bg [Medical University - Plovdiv, Faculty of Pharmacy, Department of Chemical Science15A Vassil Aprilov blvd., 4002 Plovdiv (Bulgaria); Feodorova, Y. N.; Draganov, M. M. [Medical University - Plovdiv, Medical Faculty, Department of Medical Biology, 15A Vassil Aprilov blvd., 4002 Plovdiv (Bulgaria); Girginov, Ch. A. [University of Chemical Technology and Metallurgy -Sofia, Department of Chemical Science, Subdepartment of Physical Chemistry, 8 Kliment Ohridski Blvd. 1756 Sofia (Bulgaria); Viraneva, A. P.; Yovcheva, T. A. [University of Plovdiv “Paisiy Hilendarski”, Faculty of Physics, Department of Experimental Physic, 24 Tsar Assen str., 4000 Plovdiv (Bulgaria)

    2016-03-25

    Materials for medical implants should have suitable mechanical properties, excellent biocompatibility and high corrosion resistance. They should not stimulate allergic and immunologic reactions and should not cause cancer. The use of aluminum as a construction material in implantology is continuously expanding. There are various methods for surface treatment to improve its biocompatibility. In this study aluminum samples anodized in 15% H{sub 2} SO{sub 4} or treated with positive or negative corona discharge were investigated. PDL-cell line of immortalized cells, precursors of periodontal ligament and RAW 264.7 cell line from mouse macrophages are used for the bioassays. The results show that 10 and 20 μm thick oxide film provides better development of the PLD cells, compared to untreated aluminum. Metal surfaces with 10 μm thick oxide film show the best properties in terms of cells vitality, proliferation and growth. Polymer treated but uncharged samples show good results.

  4. Surface tiny grain-dependent enhanced rate performance of MoO3 nanobelts with pseudocapacitance contribution for lithium-ion battery anode

    Science.gov (United States)

    Cao, Liyun; He, Juju; Li, Jiayin; Yan, Jingwen; Huang, Jianfeng; Qi, Ying; Feng, Liangliang

    2018-07-01

    In order to improve the rate performance of MoO3, a novel MoO3 nanobelt with tiny grains on surface (named as d-MoO3) is fabricated via one-step facile hydrothermal method with citric acid adding, in which citric acid (CA) serves as a weak reductant as well as surface modification agent. When tested as an anode in LIBs, d-MoO3 displays an improved discharge capacity of 787 mAh·g-1 at 0.1 A g-1 over 100 cycles with capacity retention of ∼91% while MoO3 decays to 50 mAh·g-1 in the 100th cycle. Notably, d-MoO3 delivers enhanced rate capability (536 and 370 mAh·g-1 at high rates of 5 and 10 A g-1 respectively). We consider these excellent electrochemical properties of d-MoO3 electrode are associated with the tiny grains on MoO3 surface, which effectively maintains the electrode's structural integrity. Even though d-MoO3 nanobelt suffers from a degree of in-situ pulverization after several cycles, these pulverized active particles can still maintain stable electrochemical contact and are highly exposed to electrolyte, realizing ultrahigh e-/Li+ diffusion kinetics. In addition, part extrinsic pseudocapacitance contribution to the Li+ storage also explains the high-rate performance. Combining all these merits, d-MoO3 is potentially a high-energy, high-power and well-stable anode material for Li ion batteries (LIBs).

  5. Film growth and alloy enrichment during anodizing AZ31 magnesium alloy in fluoride/glycerol electrolytes of a range of water contents

    Czech Academy of Sciences Publication Activity Database

    Němcová, A.; Galal, O.; Skeldon, P.; Kuběna, Ivo; Šmíd, Miroslav; Briand, E.; Vickridge, I.; Ganem, J.-J.; Habazaki, H.

    2016-01-01

    Roč. 219, NOV (2016), s. 28-37 ISSN 0013-4686 Institutional support: RVO:68081723 Keywords : magnesium * anodic film * enrichment Subject RIV: JK - Corrosion ; Surface Treatment of Materials Impact factor: 4.798, year: 2016

  6. Analyzing the anodic reactions for iron surface with a porous Al2O3 cluster with the scanning vibrating electrode

    Science.gov (United States)

    Eliyan, Faysal Fayez

    2017-09-01

    The Scanning Vibrating Electrode Technique (SVET) was used to analyze the anodic reactions inside and around a porous Al2O3 cluster embedded onto an iron foil. The tests were carried out at -0.7 V vs. Saturated Calomel Electrode, in naturally aerated solutions of 0.1, 0.2, 0.35, and 0.5 M bicarbonate concentration. During 10 h of testing, the SVET showed evidence for a formation of a passive film in and around the cluster, in the scanning area shown in the graphical abstract. In the dilute 0.1 and 0.2 M solutions, the passive films formed slower than those in 0.35 and 0.5 M solutions. In the SVET maps, the passive films showed that they could suppress dissolution to currents comparable to those of slower dissolution under the porous Al2O3 cluster.

  7. Identification of a Methane Oxidation Intermediate on Solid Oxide Fuel Cell Anode Surfaces with Fourier Transform Infrared Emission.

    Science.gov (United States)

    Pomfret, Michael B; Steinhurst, Daniel A; Owrutsky, Jeffrey C

    2013-04-18

    Fuel interactions on solid oxide fuel cell (SOFC) anodes are studied with in situ Fourier transform infrared emission spectroscopy (FTIRES). SOFCs are operated at 800 °C with CH4 as a representative hydrocarbon fuel. IR signatures of gas-phase oxidation products, CO2(g) and CO(g), are observed while cells are under load. A broad feature at 2295 cm(-1) is assigned to CO2 adsorbed on Ni as a CH4 oxidation intermediate during cell operation and while carbon deposits are electrochemically oxidized after CH4 operation. Electrochemical control provides confirmation of the assignment of adsorbed CO2. FTIRES has been demonstrated as a viable technique for the identification of fuel oxidation intermediates and products in working SOFCs, allowing for the elucidation of the mechanisms of fuel chemistry.

  8. Effects of atmospheric air plasma treatment of graphite and carbon felt electrodes on the anodic current from Shewanella attached cells.

    Science.gov (United States)

    Epifanio, Monica; Inguva, Saikumar; Kitching, Michael; Mosnier, Jean-Paul; Marsili, Enrico

    2015-12-01

    The attachment of electrochemically active microorganisms (EAM) on an electrode is determined by both the chemistry and topography of the electrode surface. Pre-treatment of the electrode surface by atmospheric air plasma introduces hydrophilic functional groups, thereby increasing cell attachment and electroactivity in short-term experiments. In this study, we use graphite and carbon felt electrodes to grow the model EAM Shewanella loihica PV-4 at oxidative potential (0.2 V vs. Ag/AgCl). Cell attachment and electroactivity are measured through electrodynamic methods. Atmospheric air plasma pre-treatment increases cell attachment and current output at graphite electrodes by 25%, while it improves the electroactivity of the carbon felt electrodes by 450%. Air plasma pre-treatment decreased the coulombic efficiency on both carbon felt and graphite electrodes by 60% and 80%, respectively. Microbially produced flavins adsorb preferentially at the graphite electrode, and air plasma pre-treatment results in lower flavin adsorption at both graphite and carbon felt electrodes. Results show that air plasma pre-treatment is a feasible option to increase current output in bioelectrochemical systems. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Electrochemical coating of dental implants with anodic porous titania for enhanced osteointegration

    Directory of Open Access Journals (Sweden)

    Amirreza Shayganpour

    2015-11-01

    Full Text Available Clinical long-term osteointegration of titanium-based biomedical devices is the main goal for both dental and orthopedical implants. Both the surface morphology and the possible functionalization of the implant surface are important points. In the last decade, following the success of nanostructured anodic porous alumina, anodic porous titania has also attracted the interest of academic researchers. This material, investigated mainly for its photocatalytic properties and for applications in solar cells, is usually obtained from the anodization of ultrapure titanium. We anodized dental implants made of commercial grade titanium under different experimental conditions and characterized the resulting surface morphology with scanning electron microscopy equipped with an energy dispersive spectrometer. The appearance of nanopores on these implants confirm that anodic porous titania can be obtained not only on ultrapure and flat titanium but also as a conformal coating on curved surfaces of real objects made of industrial titanium alloys. Raman spectroscopy showed that the titania phase obtained is anatase. Furthermore, it was demonstrated that by carrying out the anodization in the presence of electrolyte additives such as magnesium, these can be incorporated into the porous coating. The proposed method for the surface nanostructuring of biomedical implants should allow for integration of conventional microscale treatments such as sandblasting with additive nanoscale patterning. Additional advantages are provided by this material when considering the possible loading of bioactive drugs in the porous cavities.

  10. Influence of anodization parameters in the TiO2 nanotubes formation on Ti-7.5Mo alloy surface for biomedical application

    International Nuclear Information System (INIS)

    Escada, Ana Lúcia; Nakazato, Roberto Zenhei; Claro, Ana Paula Rosifini Alves

    2017-01-01

    In this study, the effects of the parameters such as applied potential difference, time and annealing temperature in the titania nanotubes formation were evaluated. The morphology of the nanotubes was evaluated by using Field Emission Gun - Scanning Electron Microscope (FEG-SEM), Atomic Force Microscope (AFM), contact angle and X-rays diffraction (XRD). Self-organized nano-structures were formed on the Ti-7.5Mo alloy surface from the same electrolyte (glycerol/NH4F) for all conditions. It was observed that the potential influenced the diameter while the length was changed according to the anodization time length. The presence of the phases anatase and rutile was altered by annealing temperature. Results showed that 20V-48h-450 deg C was the better than other conditions for application as biomaterial. (author)

  11. Dewetting of polymer thin films on modified curved surfaces: preparation of polymer nanoparticles with asymmetric shapes by anodic aluminum oxide templates.

    Science.gov (United States)

    Liu, Chih-Ting; Tsai, Chia-Chan; Chu, Chien-Wei; Chi, Mu-Huan; Chung, Pei-Yun; Chen, Jiun-Tai

    2018-04-18

    We study the dewetting behaviors of poly(methyl methacrylate) (PMMA) thin films coated in the cylindrical nanopores of anodic aluminum oxide (AAO) templates by thermal annealing. Self-assembled monolayers (SAMs) of n-octadecyltrichlorosilane (ODTS) are introduced to modify the pore surfaces of the AAO templates to induce the dewetting process. By using scanning electron microscopy (SEM), the dewetting-induced morphology transformation from the PMMA thin films to PMMA nanoparticles with asymmetric shapes can be observed. The sizes of the PMMA nanoparticles can be controlled by the original PMMA solution concentrations. The dewetting phenomena on the modified nanopores are explained by taking into account the excess intermolecular interaction free energy (ΔG). This work opens a new possibility for creating polymer nanoparticles with asymmetric shapes in confined geometries.

  12. Influence of anodization parameters in the TiO{sub 2} nanotubes formation on Ti-7.5Mo alloy surface for biomedical application

    Energy Technology Data Exchange (ETDEWEB)

    Escada, Ana Lúcia; Nakazato, Roberto Zenhei; Claro, Ana Paula Rosifini Alves, E-mail: analuciaescada@uol.com.br [Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP), Guaratinguetá, SP (Brazil). Departamento de Materiais e Tecnologia

    2017-10-15

    In this study, the effects of the parameters such as applied potential difference, time and annealing temperature in the titania nanotubes formation were evaluated. The morphology of the nanotubes was evaluated by using Field Emission Gun - Scanning Electron Microscope (FEG-SEM), Atomic Force Microscope (AFM), contact angle and X-rays diffraction (XRD). Self-organized nano-structures were formed on the Ti-7.5Mo alloy surface from the same electrolyte (glycerol/NH4F) for all conditions. It was observed that the potential influenced the diameter while the length was changed according to the anodization time length. The presence of the phases anatase and rutile was altered by annealing temperature. Results showed that 20V-48h-450 deg C was the better than other conditions for application as biomaterial. (author)

  13. Infrared radiation properties of anodized aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Kohara, S. [Science Univ. of Tokyo, Noda, Chiba (Japan). Dept. of Materials Science and Technology; Niimi, Y. [Science Univ. of Tokyo, Noda, Chiba (Japan). Dept. of Materials Science and Technology

    1996-12-31

    The infrared radiation heating is an efficient and energy saving heating method. Ceramics have been used as an infrared radiant material, because the emissivity of metals is lower than that of ceramics. However, anodized aluminum could be used as the infrared radiant material since an aluminum oxide film is formed on the surface. In the present study, the infrared radiation properties of anodized aluminum have been investigated by determining the spectral emissivity curve. The spectral emissivity curve of anodized aluminum changed with the anodizing time. The spectral emissivity curve shifted to the higher level after anodizing for 10 min, but little changed afterwards. The infrared radiant material with high level spectral emissivity curve can be achieved by making an oxide film thicker than about 15 {mu}m on the surface of aluminum. Thus, anodized aluminum is applicable for the infrared radiation heating. (orig.)

  14. Synthesis of calcium-phosphorous doped TiO{sub 2} nanotubes by anodization and reverse polarization: A promising strategy for an efficient biofunctional implant surface

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Sofia A., E-mail: sofiafonso@msn.com [CMEMS – Center of MicroElectroMechanical Systems, Department of Mechanical Engineering, University of Minho, 4800-058 Guimarães (Portugal); IBTN/US – American Branch of the Institute of Biomaterials, Tribocorrosion and Nanomedicine, UIC College of Dentistry, 60612 Chicago, IL (United States); Patel, Sweetu B. [IBTN/US – American Branch of the Institute of Biomaterials, Tribocorrosion and Nanomedicine, UIC College of Dentistry, 60612 Chicago, IL (United States); Department of Mechanical Engineering, Michigan Technological University, 49931 Houghton, MI (United States); Sukotjo, Cortino [IBTN/US – American Branch of the Institute of Biomaterials, Tribocorrosion and Nanomedicine, UIC College of Dentistry, 60612 Chicago, IL (United States); Departmenmt of Restorative Dentistry, University of Illinois at Chicago, 60612 Chicago, IL (United States); Mathew, Mathew T. [IBTN/US – American Branch of the Institute of Biomaterials, Tribocorrosion and Nanomedicine, UIC College of Dentistry, 60612 Chicago, IL (United States); Department of Orthopedic Surgery, Rush University Medical Center, 60612 Chicago, IL (United States); Department of Biomedical Science, UIC School of Medicine at Rockford, 61107 Rockford, IL (United States); Filho, Paulo N. [IBTN/Br – Brazilian Branch of the Institute of Biomaterials, Tribocorrosion and Nanomedicine, UNESP – Universidade Estadual Paulista, Faculdade de Ciências, 17033-360 Bauru, São Paulo (Brazil); Faculdade de Ciências, Departamento de Física, UNESP - Universidade Estadual Paulista, 17033-360 Bauru, São Paulo (Brazil); Celis, Jean-Pierre [Department of Materials Engineering, KU Leuven, 3001 Leuven (Belgium); and others

    2017-03-31

    Highlights: • A new surface modification methodology for bio-functionalization of TiO2 NTs is addressed • Bone-like structured TiO2 nanotubular surfaces containing Ca and P were synthesized. • Ca/P-doped TiO2 NTs enhanced adhesion and proliferation of osteoblastic-like cells. • The bio-functionalization granted improved bio-electrochemical stability to TiO2 NTs. - Abstract: The modification of surface features such as nano-morphology/topography and chemistry have been employed in the attempt to design titanium oxide surfaces able to overcome the current dental implants failures. The main goal of this study is the synthesis of bone-like structured titanium dioxide (TiO{sub 2}) nanotubes enriched with Calcium (Ca) and Phosphorous (P) able to enhance osteoblastic cell functions and, simultaneously, display an improved corrosion behavior. To achieve the main goal, TiO{sub 2} nanotubes were synthetized and doped with Ca and P by means of a novel methodology which relied, firstly, on the synthesis of TiO{sub 2} nanotubes by anodization of titanium in an organic electrolyte followed by reverse polarization and/or anodization, in an aqueous electrolyte. Results show that hydrophilic bone-like structured TiO{sub 2} nanotubes were successfully synthesized presenting a highly ordered nano-morphology characterized by non-uniform diameters. The chemical analysis of such nanotubes confirmed the presence of CaCO{sub 3}, Ca{sub 3}(PO{sub 4}){sub 2}, CaHPO{sub 4} and CaO compounds. The nanotube surfaces submitted to reverse polarization, presented an improved cell adhesion and proliferation compared to smooth titanium. Furthermore, these surfaces displayed a significantly lower passive current in artificial saliva, and so, potential to minimize their bio-degradation through corrosion processes. This study addresses a very simple and promising multidisciplinary approach bringing new insights for the development of novel methodologies to improve the outcome of osseointegrated

  15. Finding the lost open-circuit voltage in polymer solar cells by UV-ozone treatment of the nickel acetate anode buffer layer.

    Science.gov (United States)

    Wang, Fuzhi; Sun, Gang; Li, Cong; Liu, Jiyan; Hu, Siqian; Zheng, Hua; Tan, Zhan'ao; Li, Yongfang

    2014-06-25

    Efficient polymer solar cells (PSCs) with enhanced open-circuit voltage (Voc) are fabricated by introducing solution-processed and UV-ozone (UVO)-treated nickel acetate (O-NiAc) as an anode buffer layer. According to X-ray photoelectron spectroscopy data, NiAc partially decomposed to NiOOH during the UVO treatment. NiOOH is a dipole species, which leads to an increase in the work function (as confirmed by ultraviolet photoemission spectroscopy), thus benefitting the formation of ohmic contact between the anode and photoactive layer and leading to increased Voc. In addition, the UVO treatment improves the wettability between the substrate and solvent of the active layer, which facilitates the formation of an upper photoactive layer with better morphology. Further, the O-NiAc layer can decrease the series resistance (Rs) and increase the parallel resistance (Rp) of the devices, inducing enhanced Voc in comparison with the as-prepared NiAc-buffered control devices without UVO treatment. For PSCs based on the P3HT:PCBM system, Voc increases from 0.50 to 0.60 V after the NiAc buffer layer undergoes UVO treatment. Similarly, in the P3HT:ICBA system, the Voc value of the device with a UVO-treated NiAc buffer layer increases from 0.78 to 0.88 V, showing an enhanced power conversion efficiency of 6.64%.

  16. Laser surface treatment of grey cast iron for automotive applications

    NARCIS (Netherlands)

    Ocelik, V.; Tang, P.N.; de Boer, M.C.; de Oliveira, U.; de Hosson, J.T.M.; DeHosson, JTM; Brebbia, CA; Nishida, SI

    2005-01-01

    The surface of pearlitic grey cast iron was treated using a 2 kW Nd:YAG laser beam with the final aim to improve its surface properties, mainly for automotive applications. Two kinds of laser surface treatments were experimentally applied. In the laser surface hardening approach the surface of cast

  17. Sample preparation technique for transmission electron microscopy anodized Al-Li-SiC metal matrix composite

    International Nuclear Information System (INIS)

    Shahid, M.; Thomson, G.E.

    1997-01-01

    Along with improved mechanical properties, metal matrix composites (MMC) have a disadvantage of enhanced corrosion susceptibility in aggressive environments. Recent studies on corrosion behaviour of an Al-alloy 8090/SiC MMC, revealed considerably high corrosion rates of the MMC in near neutral solutions containing chloride ions. Anodizing is one of the potential surface treatment for the MMC to provide protective coating against corrosion. The surface and cross section of the anodized MMC can easily be observed using scanning electron microscope. The anodizing behaviour of the MMC can be understood further if the anodized cross section in examined under transmission electron microscope (TEM). However, it is relatively difficult to prepare small (3 mm diameter) electron transparent specimens of the MMC supporting an anodic film. In the present study a technique has been developed for preparing thin electron transparent specimens of the anodized MMC. This technique employed conventional ion beam thinning process but the preparation of small discs was a problem. A MMMC consisting of Al-alloy 8090 with 20 % (by weight) SiC particulate with an average size of 5 Mu m, was anodized and observed in TEM after preparing the samples using the above mentioned techniques. (author)

  18. Performance of two different types of anodes in membrane electrode assembly microbial fuel cells for power generation from domestic wastewater

    KAUST Repository

    Hays, Sarah

    2011-10-01

    Graphite fiber brush electrodes provide high surface areas for exoelectrogenic bacteria in microbial fuel cells (MFCs), but the cylindrical brush format limits more compact reactor designs. To enable MFC designs with closer electrode spacing, brush anodes were pressed up against a separator (placed between the electrodes) to reduce the volume occupied by the brush. Higher maximum voltages were produced using domestic wastewater (COD = 390 ± 89 mg L-1) with brush anodes (360 ± 63 mV, 1000 Ω) than woven carbon mesh anodes (200 ± 81 mV) with one or two separators. Maximum power densities were similar for brush anode reactors with one or two separators after 30 days (220 ± 1.2 and 240 ± 22 mW m-2), but with one separator the brush anode MFC power decreased to 130 ± 55 mW m-2 after 114 days. Power densities in MFCs with mesh anodes were very low (<45 mW m-2). Brush anodes MFCs had higher COD removals (80 ± 3%) than carbon mesh MFCs (58 ± 7%), but similar Coulombic efficiencies (8.6 ± 2.9% brush; 7.8 ± 7.1% mesh). These results show that compact (hemispherical) brush anodes can produce higher power and more effective domestic wastewater treatment than flat mesh anodes in MFCs. © 2011 Elsevier B.V. All rights reserved.

  19. Shot peening as a pre-treatment to anodic oxidation coating process of AW 6082 aluminum for fatigue life improvement

    Czech Academy of Sciences Publication Activity Database

    Hadzima, B.; Nový, F.; Trško, L.; Pastorek, F.; Jambor, M.; Fintová, Stanislava

    2017-01-01

    Roč. 93, 9-12 (2017), s. 3315-3323 ISSN 0268-3768 R&D Projects: GA MŠk(CZ) LQ1601 Institutional support: RVO:68081723 Keywords : Fatigue life * AW 6082 aluminum alloy * Anodizing * Shot peening * Ultrasonic fatigue testing Subject RIV: JL - Materials Fatigue, Friction Mechanics OBOR OECD: Audio engineering, reliability analysis Impact factor: 2.209, year: 2016 https://link.springer.com/content/pdf/10.1007%2Fs00170-017-0776-1.pdf

  20. Surface treatment of new type aluminum lithium alloy and fatigue crack behaviors of this alloy plate bonded with Ti–6Al–4V alloy strap

    International Nuclear Information System (INIS)

    Sun, Zhen-Qi; Huang, Ming-Hui; Hu, Guo-Huai

    2012-01-01

    Highlights: ► A new generation aluminum lithium alloy which special made for Chinese commercial plane was investigated. ► Pattern of aluminum lithium alloy and Ti alloy were shown after anodization. ► Crack propagation of samples bonded with different wide Ti straps were studied in this paper. -- Abstract: Samples consisting of new aluminum lithium alloy (Al–Li alloy) plate developed by the Aluminum Company of America and Ti–6Al–4V alloy (Ti alloy) plate were investigated. Plate of 400 mm × 140 mm × 2 mm with single edge notch was anodized in phosphoric solution and Ti alloy plate of 200 mm × 20 (40) mm × 2 mm was anodized in alkali solution. Patterns of two alloys were studied at original/anodized condition. And then, aluminum alloy and Ti alloy plates were assembled into a sample with FM 94 film adhesive. Fatigue crack behaviors of the sample were investigated under condition of nominal stress σ = 36 MPa and 54 MPa, stress ratio of 0.1. Testing results show that anodization treatment modifies alloys surface topography. Ti alloy bonding to Al–Li alloy plate effectively retards crack growth than that of Al–Li alloy plate. Fatigue life of sample bonded with Ti alloy strap improves about 62.5% than that of non-strap plate.

  1. Optimized coupling of a submerged membrane electro-bioreactor with pre-anaerobic reactors containing anode electrodes for wastewater treatment and fouling reduction

    Directory of Open Access Journals (Sweden)

    Nader Taghipour

    2017-09-01

    Full Text Available In this paper, the performance of a submerged membrane electro-bioreactor with pre-anaerobic reactors containing anode electrodes (SMEBR+ was compared with that of a membrane bioreactor (MBR in municipal wastewater treatment. The new design idea of the SMEBR+ was based on applications of direct current (DC on the anode and cathode electrodes. The pilot study was divided into 2 stages and operated for 48 days. In Stage I, the MBR was continuously operated for 24 days without the application of electrodes. In Stage II, the SMEBR+ was continuously operated for 24 days, while aluminum electrodes and an intermittent DC were working with an operational mode of 2 min ON/4 min OFF at a constant voltage of 1.4 V. The results indicated that membrane fouling was reduced by nearly 22.02% in the SMEBR+ compared to the MBR. The results also showed that the SMEBR+ increased the quality of effluent to the extent that high removals of NH3+-N, PO43−-P, and chemical oxygen demand (COD were 98%, 76%, and 90%, respectively. This system, in comparison with those proposed in other studies, showed a suitable improvement in biological treatments, considering the high removal of NH3+-N. Therefore, SMEBR+ can be considered as a promising treatment alternative to the conventional MBR.

  2. Mixed resin and carbon fibres surface treatment for preparation of carbon fibres composites with good interfacial bonding strength

    International Nuclear Information System (INIS)

    He, Hongwei; Wang, Jianlong; Li, Kaixi; Wang, Jian; Gu, Jianyu

    2010-01-01

    The objective of this work is to improve the interlaminar shear strength of composites by mixing epoxy resin and modifying carbon fibres. The effect of mixed resin matrix's structure on carbon fibres composites was studied. Anodic oxidation treatment was used to modify the surface of carbon fibres. The tensile strength of multifilament and interlaminar shear strength of composites were investigated respectively. The morphologies of untreated and treated carbon fibres were characterized by scanning electron microscope and X-ray photoelectron spectroscopy. Surface analysis indicates that the amount of carbon fibres chemisorbed oxygen-containing groups, active carbon atom, the surface roughness, and wetting ability increases after treatment. The tensile strength of carbon fibres decreased little after treatment by anodic oxidation. The results show that the treated carbon fibres composites could possess excellent interfacial properties with mixed resins, and interlaminar shear strength of the composites is up to 85.41 MPa. The mechanism of mixed resins and treated carbon fibres to improve the interfacial property of composites is obtained.

  3. Ion implantation as an efficient surface treatment

    International Nuclear Information System (INIS)

    Straede, C.A.

    1992-01-01

    Ion beam processing has for several years been well established in the semiconductor industry. In recent years ion implantation of tool steels, ceramics and even plastics has gained increasing industrial awareness. The development of ion implantation to a commercially viable surface treatment of tools and spare parts working in production type environments is very dependent on technical merits, economic considerations, competing processes and highly individual barriers to acceptance for each particular application. Some examples of this will be discussed. The development of the process is very closely linked with the development of high current accelerators and their ability to efficiently manipulate the samples being treated, or to make sample manipulation superfluous by using special beam systems like the PSII. Furthermore, the ability to produce high beam currents (mA) of a wide variety of ions is crucial. Previously, it was broadly accepted that ion implantation of tools on a commercial basis generally had to be limited to nitrogen implantation. The development of implanters which can produce high beam currents of ions like B + , C + , Ti + , Cr + and others is rapidly changing this situation, and today an increasing number of commercial implantations are performed with these ions although nitrogen is still successfully used in the majority of commercial implantation. All in all, the recent development of equipment makes it possible to a higher extent than before to tailor the implantation to a specific situation. The emerging new possibilities in this direction will be discussed, and a broad selection of practical examples of ion implantation at standard low temperatures of tools and spare parts will be given. Furthermore, very interesting results have been obtained recently by implanting nitrogen at elevated temperatures, which yields a relatively deep penetration of the implanted ions. (orig./WL)

  4. Vacuum arc anode phenomena

    International Nuclear Information System (INIS)

    Miller, H.C.

    1976-01-01

    A brief review of anode phenomena in vacuum arcs is presented. Discussed in succession are: the transition of the arc into the anode spot mode; the temperature of the anode before, during and after the anode spot forms; and anode ions. Characteristically the anode spot has a temperature of the order of the atmospheric boiling point of the anode material and is a copious source of vapor and energetic ions. The dominant mechanism controlling the transition of the vacuum arc into the anode spot mode appears to depend upon the electrode geometry, the electrode material, and the current waveform of the particular vacuum arc being considered. Either magnetic constriction in the gap plasma or gross anode melting can trigger the transition; indeed, a combination of the two is a common cause of anode spot formation

  5. Geobacter Dominates the Inner Layers of a Stratified Biofilm on a Fluidized Anode During Brewery Wastewater Treatment

    Directory of Open Access Journals (Sweden)

    Sara Tejedor-Sanz

    2018-03-01

    Full Text Available In this study, we designed a microbial electrochemical fluidized bed reactor (ME-FBR, with an electroconductive anodic bed made of activated carbon particles for treating a brewery wastewater. Under a batch operating mode, acetate and propionate consumption rates were 13-fold and 2.4-fold higher, respectively, when the fluidized anode was polarized (0.2 V with respect to open circuit conditions. Operating in a continuous mode, this system could effectively treat the brewery effluent at organic loading rates (OLR over 1.7 kg m-3NRV d-1 and with removal efficiencies of 95 ± 1.4% (hydraulic retention time of 1 day and an influent of 1.7 g-COD L-1. The coulombic efficiency values highly depended upon the OLR applied, and varied from a 56 ± 15% to 10 ± 1%. Fluorescence in situ hybridization (FISH analysis revealed a relative high abundance of Geobacter species (ca. 20%, and clearly showed a natural microbial stratification. Interestingly, the Geobacter cluster was highly enriched in the innermost layers of the biofilm (thickness of 10 μm, which were in contact with the electroconductive particles of bed, whereas the rest of bacteria were located in the outermost layers. To our knowledge, this is the first time that such a clear microbial stratification has been observed on an anode-respiring biofilm. Our results revealed the relevant role of Geobacter in switching between the electrode and other microbial communities performing metabolic reactions in the outermost environment of the biofilm.

  6. Bioinspired Surface Treatments for Improved Decontamination: Icephobic Surfaces

    Science.gov (United States)

    2017-06-26

    5 TABLES Table 1 — Contact angles ...fluorosilane to produce both texture and hydrophobic properties. [1, 2] The coating technology is reported to produce a water contact angle of greater than...160° with sliding angles ᝺° classifying the surface as superhydrophobic (water contact angles >150°). The durability of the material was previously

  7. Influence of surface treatments on micropore structure and hydrogen adsorption behavior of nanoporous carbons.

    Science.gov (United States)

    Kim, Byung-Joo; Park, Soo-Jin

    2007-07-15

    The scope of this work was to control the pore sizes of porous carbons by various surface treatments and to investigate the relation between pore structures and hydrogen adsorption capacity. The effects of various surface treatments (i.e., gas-phase ozone, anodic oxidation, fluorination, and oxygen plasma) on the micropore structures of porous carbons were investigated by N(2)/77 K isothermal adsorption. The hydrogen adsorption capacity was measured by H(2) isothermal adsorption at 77 K. In the result, the specific surface area and micropore volume of all of the treated samples were slightly decreased due to the micropore filling or pore collapsing behaviors. It was also found that in F(2)-treated carbons the center of the pore size distribution was shifted to left side, meaning that the average size of the micropores decreased. The F(2)- and plasma-treated samples showed higher hydrogen storage capacities than did the other samples, the F(2)-treated one being the best, indicating that the micropore size of the porous carbons played a key role in the hydrogen adsorption at 77 K.

  8. Influence of the heat treatment condition of alloy AlCu4Mg1 on the microstructure and properties of anodic oxide layers

    Science.gov (United States)

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

    2017-03-01

    Due to their outstanding specific mechanical properties, high-strength, age-hardenable aluminum alloys offer a high potential for lightweight security-related applications. However, the use of copper-alloyed aluminum is limited because of their susceptibility to selective corrosion and their low wear resistance. These restrictions can be overcome and new applications can be opened up by the generation of protective anodic aluminum oxide layers. In contrast to the anodic oxidation of unalloyed aluminum, oxide layers produced on copper-rich alloys exhibit a significantly more complex pore structure. It is the aim of the investigation to identify the influence of microstructural parameters such as size and distribution of the strengthening precipitations on the coating microstructure. The aluminum alloy EN AW-2024 (AlCu4Mg1) in different heat treatment conditions serves as substrate material. The influence of the strengthening precipitations’ size and distribution on the development of the pore structure is investigated by the use of high-resolution scanning electron microscopy. Integral coating properties are characterized by non-destructive and light-microscopic thickness measurements and instrumented indentation tests.

  9. Electricity generation using chocolate industry wastewater and its treatment in activated sludge based microbial fuel cell and analysis of developed microbial community in the anode chamber.

    Science.gov (United States)

    Patil, Sunil A; Surakasi, Venkata Prasad; Koul, Sandeep; Ijmulwar, Shrikant; Vivek, Amar; Shouche, Y S; Kapadnis, B P

    2009-11-01

    Feasibility of using chocolate industry wastewater as a substrate for electricity generation using activated sludge as a source of microorganisms was investigated in two-chambered microbial fuel cell. The maximum current generated with membrane and salt bridge MFCs was 3.02 and 2.3 A/m(2), respectively, at 100 ohms external resistance, whereas the maximum current generated in glucose powered MFC was 3.1 A/m(2). The use of chocolate industry wastewater in cathode chamber was promising with 4.1 mA current output. Significant reduction in COD, BOD, total solids and total dissolved solids of wastewater by 75%, 65%, 68%, 50%, respectively, indicated effective wastewater treatment in batch experiments. The 16S rDNA analysis of anode biofilm and suspended cells revealed predominance of beta-Proteobacteria clones with 50.6% followed by unclassified bacteria (9.9%), alpha-Proteobacteria (9.1%), other Proteobacteria (9%), Planctomycetes (5.8%), Firmicutes (4.9%), Nitrospora (3.3%), Spirochaetes (3.3%), Bacteroides (2.4%) and gamma-Proteobacteria (0.8%). Diverse bacterial groups represented as members of the anode chamber community.

  10. Optimum Exploration for the Self-Ordering of Anodic Porous Alumina Formed via Selenic Acid Anodizing

    OpenAIRE

    Akiya, Shunta; Kikuchi, Tatsuya; Natsui, Shungo; Suzuki, Ryosuke O.

    2015-01-01

    Improvements of the regularity of the arrangement of anodic porous alumina formed by selenic acid anodizing were investigated under various operating conditions. The oxide burning voltage increased with the stirring rate of the selenic acid solution, and the high applied voltage without oxide burning was achieved by vigorously stirring the solution. The regularity of the porous alumina was improved as the anodizing time and surface flatness increased. Conversely, the purity of the 99.5–99.999...

  11. Surface noble metal modified PdM/C (M = Ru, Pt, Au) as anode catalysts for direct ethanol fuel cells

    International Nuclear Information System (INIS)

    Mao, Han; Huang, Tao; Yu, Aishui

    2016-01-01

    In this article, we studied the surface noble metal modification on Pd nanoparticles, other than the homogeneous or core-shell structure. The surface modification will lead to the uneven constitution within the nanoparticles and thus more obvious optimization effect toward the catalyst brought by the lattice deformation. The surface of the as-prepared Pd nanoparticles was modified with Ru, Pt or Au by a moderate and green approach, respectively. XPS results confirm the interactive electron effects between Pd and the modified noble metal. Electrochemical measurements show that the surface noble metal modified catalysts not only show higher catalytic activity, but also better stability and durability. The PdM/C catalysts all exhibit good dispersion and very little agglomeration after long-term potential cycles toward ethanol oxidation. With only 10% metallic atomic ratio of Au, PdAu/C catalyst shows extraordinary catalytic activity and stability, the peak current reaches 1700 mA mg"−"1 Pd, about 2.5 times that of Pd/C. Moreover, the PdAu/C maintains 40% of the catalytic activity after 4500 potential cycles. - Highlights: • Pd-based catalysts with complicated exposed facets. • Much enhanced electrocatalytic activity and stability with about 10% noble metal M (M = Ru, Pt, Au) on Pd nanoparticles. • The outstanding electrocatalytic performance of PdAu/C towards ethanol oxidation after the Au modification.

  12. Surface noble metal modified PdM/C (M = Ru, Pt, Au) as anode catalysts for direct ethanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Han; Huang, Tao, E-mail: huangt@fudan.edu.cn; Yu, Aishui, E-mail: asyu@fudan.edu.cn

    2016-08-15

    In this article, we studied the surface noble metal modification on Pd nanoparticles, other than the homogeneous or core-shell structure. The surface modification will lead to the uneven constitution within the nanoparticles and thus more obvious optimization effect toward the catalyst brought by the lattice deformation. The surface of the as-prepared Pd nanoparticles was modified with Ru, Pt or Au by a moderate and green approach, respectively. XPS results confirm the interactive electron effects between Pd and the modified noble metal. Electrochemical measurements show that the surface noble metal modified catalysts not only show higher catalytic activity, but also better stability and durability. The PdM/C catalysts all exhibit good dispersion and very little agglomeration after long-term potential cycles toward ethanol oxidation. With only 10% metallic atomic ratio of Au, PdAu/C catalyst shows extraordinary catalytic activity and stability, the peak current reaches 1700 mA mg{sup −1} Pd, about 2.5 times that of Pd/C. Moreover, the PdAu/C maintains 40% of the catalytic activity after 4500 potential cycles. - Highlights: • Pd-based catalysts with complicated exposed facets. • Much enhanced electrocatalytic activity and stability with about 10% noble metal M (M = Ru, Pt, Au) on Pd nanoparticles. • The outstanding electrocatalytic performance of PdAu/C towards ethanol oxidation after the Au modification.

  13. [INVITED] Laser treatment of Inconel 718 alloy and surface characteristics

    Science.gov (United States)

    Yilbas, B. S.; Ali, H.; Al-Aqeeli, N.; Karatas, C.

    2016-04-01

    Laser surface texturing of Inconel 718 alloy is carried out under the high pressure nitrogen assisting gas. The combination of evaporation and melting at the irradiated surface is achieved by controlling the laser scanning speed and the laser output power. Morphological and metallurgical changes in the treated surface are analyzed using the analytical tools including optical, electron scanning, and atomic force microscopes, energy dispersive spectroscopy, and X-ray diffraction. Microhardnes and friction coefficient of the laser treated surface are measured. Residual stress formed in the surface region is determined from the X-ray diffraction data. Surface hydrophobicity of the laser treated layer is assessed incorporating the sessile drop method. It is found that laser treated surface is free from large size asperities including cracks and the voids. Surface microhardness increases significantly after the laser treatment process, which is attributed to the dense layer formation at the surface under the high cooling rates, dissolution of Laves phase in the surface region, and formation of nitride species at the surface. Residual stress formed is compressive in the laser treated surface and friction coefficient reduces at the surface after the laser treatment process. The combination of evaporation and melting at the irradiated surface results in surface texture composes of micro/nano-poles and pillars, which enhance the surface hydrophobicity.

  14. Electronic properties of electrolyte/anodic alumina junction during porous anodizing

    Energy Technology Data Exchange (ETDEWEB)

    Vrublevsky, I. [Department of Microelectronics, Belarusian State University of Informatics and Radioelectronics, 6 Brovka Street, Minsk 220013 (Belarus)]. E-mail: nil-4-2@bsuir.edu.by; Jagminas, A. [Institute of Chemistry, A. Gostauto 9, LT-01108 Vilnius (Lithuania); Schreckenbach, J. [Institut fuer Chemie, Technische Universitaet Chemnitz, Chemnitz D-09107 (Germany); InnoMat GmbH, Chemnitz (Germany); Goedel, Werner A. [Institut fuer Chemie, Technische Universitaet Chemnitz, Chemnitz D-09107 (Germany)

    2007-03-15

    The growth of porous oxide films on aluminum (99.99% purity), formed in 4% phosphoric acid was studied as a function of the anodizing voltage (23-53 V) using a re-anodizing technique and transmission electron microscopy (TEM) study. The chemical dissolution behavior of freshly anodized and annealed at 200 deg. C porous alumina films was studied. The obtained results indicate that porous alumina has n-type semiconductive behavior during anodizing in 4% phosphoric acid. During anodising, up to 39 V in the barrier layer of porous films, one obtains an accumulation layer (the thickness does not exceed 1 nm) where the excess electrons have been injected into the solid producing a downward bending of the conductive and valence band towards the interface. The charge on the surface of anodic oxide is negative and decreases with growing anodizing voltage. At the anodizing voltage of about 39 V, the charge on the surface of anodic oxide equals to zero. Above 39 V, anodic alumina/electrolyte junction injects protons from the electrolyte. These immobile positive charges in the surface layer of oxide together with an ionic layer of hydroxyl ions concentrated near the interface create a field, which produces an upward bending of the bands.

  15. Effects of surface treatments on microstructure in stainless steel

    International Nuclear Information System (INIS)

    Mabuchi, Yasuhiro; Tamako, Hiroaki; Kaneda, Junya; Yamashita, Norimichi; Miyakawa, Masahiko

    2009-01-01

    It is revealed that Stress Corrosion Cracking (SCC) on the surface of the L-grade stainless steels in Nuclear Power Plants is caused by heavily cold work of the materials. The microstructure, hardness and residual stress on the surface of the material are factors for SCC initiation. There are surface treatment methods that is effective reduction on SCC such as Flap Wheel (FW) polishing, Clean N Strip (CNS) polishing, Water Jet Peening (WJP) and Shot Peening (SP). In this paper, the characteristics of the surface cold worked layer of the L-grade stainless steels conducted by above-mentioned surface treatments are analyzed, and effects of the surface treatments on the surface layer are discussed. (author)

  16. Surface modification of polymer nanofibres by plasma treatment

    International Nuclear Information System (INIS)

    Wei, Q.F.; Gao, W.D.; Hou, D.Y.; Wang, X.Q.

    2005-01-01

    Polymer nanofibres have great potential for technical applications in biomaterials, filtration, composites and electronics. The surface properties of nanofibres are of importance in these applications. In this study, cold gas plasma treatment was used to modify the surface of polyamide 6 nanofibres prepared by electrospinning. The chemical nature of the nanofibre surfaces was examined by X-ray photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) was employed to study the surface characteristics of the fibres. The AFM results indicate a significant change in the morphology of the fibre surface before and after plasma treatment. A Philips Environmental Scanning Electron Microscopy (ESEM) was also used to study the wetting behaviour of the fibres. In the ESEM, relative humidity was raised to 100% to facilitate the water condensation onto fibre surfaces for wetting observation. The ESEM observation revealed that the plasma treatment significantly altered the surface wettability of the polyamide 6 nanofibres

  17. Ultrasonic Surface Treatment of Titanium Alloys. The Submicrocrystalline State

    Science.gov (United States)

    Klimenov, V. A.; Vlasov, V. A.; Borozna, V. Y.; Klopotov, A. A.

    2015-09-01

    The paper presents the results of the research on improvement of physical-and- mechanical properties of titanium alloys VT1-0 and VT6 by modification of surfaces using ultrasonic treatment, and a comprehensive study of the microstructure and mechanical properties of modified surface layers. It has been established that exposure to ultrasonic treatment leads to formation in the surface layer of a structure with an average size of elements 50 - 100 nm, depending on the brand of titanium alloy.

  18. The effect of surface treatment and gaseous rust protection paper on the atmospheric corrosion stability of aluminium alloy

    International Nuclear Information System (INIS)

    Gao Guizhong

    1992-03-01

    The experimental results of atmospheric corrosion of 166 aluminium alloy of Al-Mg-Si-Cu system and 167 aluminium alloy of Al-Mg-Si-Cu-Fe-Ni system for different surface treatment and different wrapping papers used are introduced. The results show: 1. The composition of aluminium alloy has some effect on the performance of atmospheric corrosion stability and the local corrosion depth for 167 aluminium alloy specimen is considerable. 2. After 8 years storage, the 167 aluminium alloy tubular specimen, which was treated with surface treatment in deionized water at 100 ∼ 230 C degree, has no spot of atmospheric corrosion found. 3. Within the test period, the performance of atmospheric corrosion stability by sulphuric-acid anodization film is remarkable. 4. The No. 19 gaseous rust protection paper has no effect of atmospheric corrosion stability on the 166 and 167 aluminium alloys which were treated with quenching and natural ageing method

  19. In-situ synthesized ZnFe2O4 firmly anchored to the surface of MWCNTs as a long-life anode material with high lithium storage performance

    Science.gov (United States)

    Yang, Tianbo; Zhang, Wanxi; Li, Linlin; Jin, Bo; Jin, Enmei; Jeong, Sangmoon; Jiang, Qing

    2017-12-01

    Because of two different metal cations in the crystal structures, binary transition metal oxides possess a lot of unique properties. ZnFe2O4 emerges from these transition metal oxides on account of its high theoretical capacity (1072 mAh g-1). One-dimensional multi-walled carbon nanotubes (MWCNTs) would be a desirable conductive additive for ZnFe2O4, thereby improving the electrochemical performance of ZnFe2O4. In this work, we prepare ZnFe2O4/MWCNTs by solvothermal method with further heat-treatment. ZnFe2O4 nanoparticles are firmly anchored to the surface of MWCNTs. ZnFe2O4/MWCNTs nanocomposite displays high specific capacity (1278 mAh g-1 at a current density of 200 mA g-1 after 200 cycles, and 565 mAh g-1 at a current density of 1500 mA g-1 after 500 cycles), and good rate performance (367 mAh g-1 even at a current density of 6000 mAh g-1 after 80 cycles). The superior electrochemical performance may promote ZnFe2O4 to be a promising alternative anode in lithium-ion batteries.

  20. Self-assembly surface modified indium-tin oxide anodes for single-layer light-emitting diodes

    CERN Document Server

    Morgado, J; Charas, A; Matos, M; Alcacer, L; Cacialli, F

    2003-01-01

    We study the effect of indium-tin oxide surface modification by self assembling of highly polar molecules on the performance of single-layer light-emitting diodes (LEDs) fabricated with polyfluorene blends and aluminium cathodes. We find that the efficiency and light-output of such LEDs is comparable to, and sometimes better than, the values obtained for LEDs incorporating a hole injection layer of poly(3,4-ethylene dioxythiophene) doped with polystyrene sulphonic acid. This effect is attributed to the dipole-induced work function modification of indium-tin oxide.

  1. Self-assembly surface modified indium-tin oxide anodes for single-layer light-emitting diodes

    International Nuclear Information System (INIS)

    Morgado, Jorge; Barbagallo, Nunzio; Charas, Ana; Matos, Manuel; Alcacer, Luis; Cacialli, Franco

    2003-01-01

    We study the effect of indium-tin oxide surface modification by self assembling of highly polar molecules on the performance of single-layer light-emitting diodes (LEDs) fabricated with polyfluorene blends and aluminium cathodes. We find that the efficiency and light-output of such LEDs is comparable to, and sometimes better than, the values obtained for LEDs incorporating a hole injection layer of poly(3,4-ethylene dioxythiophene) doped with polystyrene sulphonic acid. This effect is attributed to the dipole-induced work function modification of indium-tin oxide

  2. Effect of Surface Treatment on the Surface Characteristics of AISI 316L Stainless Steel

    Science.gov (United States)

    Trigwell, Steve; Selvaduray, Guna

    2005-01-01

    The ability of 316L stainless steel to maintain biocompatibility, which is dependent upon the surface characteristics, is critical to its effectiveness as an implant material. The surfaces of mechanically polished (MP), electropolished (EP) and plasma treated 316L stainless steel coupons were characterized by X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES) for chemical composition, Atomic Force Microscopy for surface roughness, and contact angle measurements for critical surface tension. All surfaces had a Ni concentration that was significantly lower than the bulk concentration of -43%. The Cr content of the surface was increased significantly by electropolishing. The surface roughness was also improved significantly by electropolishing. Plasma treatment had the reverse effect - the surface Cr content was decreased. It was also found that the Cr and Fe in the surface exist in both the oxide and hydroxide states, with the ratios varying according to surface treatment.

  3. Atomic force microscopy analysis of different surface treatments of Ti dental implant surfaces

    International Nuclear Information System (INIS)

    Bathomarco, R.V.; Solorzano, G.; Elias, C.N.; Prioli, R.

    2004-01-01

    The surface of commercial unalloyed titanium, used in dental implants, was analyzed by atomic force microscopy. The morphology, roughness, and surface area of the samples, submitted to mechanically-induced erosion, chemical etching and a combination of both, were compared. The results show that surface treatments strongly influence the dental implant physical and chemical properties. An analysis of the length dependence of the implant surface roughness shows that, for scan sizes larger than 50 μm, the average surface roughness is independent of the scanning length and that the surface treatments lead to average surface roughness in the range of 0.37 up to 0.48 μm. It is shown that the implant surface energy is sensitive to the titanium surface area. As the area increases there is a decrease in the surface contact angle

  4. Atomic force microscopy analysis of different surface treatments of Ti dental implant surfaces

    Science.gov (United States)

    Bathomarco, Ti R. V.; Solorzano, G.; Elias, C. N.; Prioli, R.

    2004-06-01

    The surface of commercial unalloyed titanium, used in dental implants, was analyzed by atomic force microscopy. The morphology, roughness, and surface area of the samples, submitted to mechanically-induced erosion, chemical etching and a combination of both, were compared. The results show that surface treatments strongly influence the dental implant physical and chemical properties. An analysis of the length dependence of the implant surface roughness shows that, for scan sizes larger than 50 μm, the average surface roughness is independent of the scanning length and that the surface treatments lead to average surface roughness in the range of 0.37 up to 0.48 μm. It is shown that the implant surface energy is sensitive to the titanium surface area. As the area increases there is a decrease in the surface contact angle.

  5. Valoración de los principales parámetros que definen la calidad de las superficies anodizadas en piezas de aluminio para la construcción. // Evaluation of anodized surfaces main parameters that define quality of aluminum parts.

    Directory of Open Access Journals (Sweden)

    J. A. Pérez García

    2004-01-01

    Full Text Available Actualmente en la construcción de edificaciones se utiliza profusamente el aluminio en puertas, ventanas, pasamanos, etc.Con el objetivo de mejorar los parámetros que caracterizan sus cualidades estéticas y de resistencia a la corrosión, estosartículos son sometidos al proceso de anodizado. De todos los factores que intervienen en este proceso, se ha llegado aconocer que hay tres que tienen mayor relevancia en la obtención de la calidad deseada en las piezas: tratamiento previo dela superficie a anodizar, color a aplicar y espesor de la capa de recubrimiento. Este trabajo ofrece, sobre la base deexperimentos llevados a cabo, las relaciones cualitativas entre estos factores y los parámetros que caracterizan la calidaddesde el punto de vista estético (brillo, aspecto, textura y de su resistencia a la corrosión.Palabras claves: Aluminio, anodizado, calidad.__________________________________________________________________________Abstract.Aluminum articles such as windows and doors, etc are widely applied in modern building construction. In order to upgradeaesthetic and corrosion resistant properties of these articles the anodizing process is frequently used. Among all factors thatare involved in this process, there are three having high relevance in order to obtain the desired quality of the final product:previous surface treatment (before anodizing, color of the final article and anodized layers thickness. This paper offers thequalitative relationships between these factors and parameters characterizing corrosion resistance properties and aesthetics.Key words: Aluminun, anodize, quality.

  6. Anodizing of aluminum with improved corrosion properties

    International Nuclear Information System (INIS)

    John, P.; Khan, I.U.

    2010-01-01

    Anodizing of aluminum was studied in sulphuric/oxalic/boric acid electroiyte system. The corrosion resistance of the anodic oxide coating of aluminum was determined by potentiodynamic polarization test and scanning electron microscope (SEM) was used to investigate the surface morphology before and after corrosion test. It was found that the oxide coating obtained by this method showed better corrosion resistance with no significant difference in surface morphology. (author)

  7. Effect of various de-anodizing techniques on the surface stability of non-colored and colored nanoporous AAO films in acidic solution

    Energy Technology Data Exchange (ETDEWEB)

    Awad, Ahmed M. [Chemical Engineering & Pilot Plant Department, National Research Centre, Dokki, Giza (Egypt); Shehata, Omnia S. [Physical Chemistry Department, National Research Centre, Dokki, Giza (Egypt); Heakal, Fakiha El-Taib, E-mail: fakihaheakal@yahoo.com [Chemistry Department, Faculty of Science, Cairo University, Giza 12613 (Egypt)

    2015-12-30

    Highlights: • Three de-anodization methods were used during two-step fabrication of nanoporous AAO. • Electrolytic etching (EE), chemical etching with H{sub 3}PO{sub 4} (PE) or NaOH (HE) were adopted. • After the second anodizing step, HE film was the thinnest as compared to EE and HE. • Stability order of nanoporous AAO films in 0.5 M HCl solution was: PE > EE > HE. • For the colored films by electrodeposited Cu atoms, the order was: HE > EE > PE. - Abstract: Anodic aluminum oxide (AAO) is well known as an important nanostructured material, and a useful template in the fabrication of nanostructures. Nanoporous anodic alumina (PAA) with high open porosity was prepared by adopting three de-anodizing regimes following the first anodizing step and preceding the second one. The de-anodizing methods include electrolytic etching (EE) and chemical etching using either phosphoric acid (PE) or sodium hydroxide (HE) solutions. Three of the obtained AAO samples were black colored by electrodeposition of copper nanoparticles in their pores. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques were used to characterize the electrochemical performance of the two sets of the prepared samples. In general, the data obtained in aggressive aerated 0.5 M HCl solution demonstrated dissimilar behavior for the three prepared samples despite that the second anodizing step was the same for all of them. The data indicated that the resistance and thickness of the inner barrier part of nano-PAA film, are the main controlling factors determining its stability. On the other hand, coloring the film decreased its stability due to the galvanic effect. The difference in the electrochemical behavior of the three colored samples was discussed based on the difference in both the pore size and thickness of the outer porous part of PAA film as supported by SEM, TEM and cross-sectional micrographs. These results can thus contribute for better engineering

  8. EFFECT OF PHOSPHORIC ACID CONCENTRATION AND ANODIZING TIME ON THE PROPERTIES OF ANODIC FILMS ON TITANIUM

    Directory of Open Access Journals (Sweden)

    DIMAS L. TORRES

    2015-07-01

    Full Text Available In this study, it was investigated the influence of electrolyte concentration and anodizing time on the electrochemical behaviour and morphology of anodic films formed on commercially pure Ti. Electrochemical methods and surface analyses were used to characterize the films. It was found that the electrolyte concentration and anodizing time affect the growth and protective characteristics of films in a physiologic medium. It was possible to observe their non-uniformity on Ti substrates under the tested conditions. In potentiodynamic profiles, it was observed that passivation current values are affected by an anodizing time increase. Variations in impedance spectra were associated with an increase of defects within the film.

  9. Rapid temperature increase near the anode and cathode in the afterglow of a pulsed positive streamer discharge

    Science.gov (United States)

    Ono, Ryo

    2018-06-01

    The spatiotemporal evolution of the temperature in the afterglow of point-to-plane, pulsed positive streamer discharge was measured near the anode tip and cathode surface using laser-induced predissociation fluorescence of OH radicals. The temperature exhibited a rapid increase and displayed a steep spatial gradient after a discharge pulse. The rate of temperature rise reached 84 K μs‑1 at mm, where z represents the distance from the anode tip. The temperature rise was much faster than in the middle of the gap; it was only 2.8 K μs‑1 at mm. The temperature reached 1700 K near the anode tip at s and 1500 K near the cathode surface at s, where t represents the postdischarge time. The spatial gradient reached 1280 K mm‑1 near the anode tip at s. The mechanism responsible for the rapid temperature increase was discussed, including rapid heating of the gas in the early postdischarge phase (s), and vibration-to-translation energy transfer in the later postdischarge phase (s). The high temperatures near the anode tip and cathode surface are particularly important for the ignition of combustible mixtures and for surface treatments, including solid-surface treatments, water treatments, and plasma medicine using pulsed streamer discharges.

  10. An Insoluble Titanium-Lead Anode for Sulfate Electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Ferdman, Alla

    2005-05-11

    measurable anode weight loss during this time period. Quantitative chemical analysis of the anode surface showed that the lead content after testing remained at its initial level. No lead dissolution or transfer from the anode to the product occurred.A key benefit of the titanium-lead anode design is that cobalt additions to copper electrolyte should be eliminated. Cobalt is added to the electrolyte to help stabilize the lead oxide surface of conventional lead anodes. The presence of the titanium intimately mixed with the lead should eliminate the need for cobalt stabilization of the lead surface. The anode should last twice as long as the conventional lead anode. Energy savings should be achieved due to minimizing and stabilizing the anode-cathode distance in the electrowinning cells. The anode is easily substitutable into existing tankhouses without a rectifier change.The copper electrowinning test data indicate that the titanium-lead anode is a good candidate for further testing as a possible replacement for a conventional lead anode. A key consideration is the cost. Titanium costs have increased. One of the ways to get the anode cost down is manufacturing the anodes with fewer cylinders. Additional prototypes having different number of cylinders were constructed for a long-term commercial testing in a circuit without cobalt. The objective of the testing is to evaluate the need for cobalt, investigate the effect of decreasing the number of cylinders on the anode performance, and to optimize further the anode design in order to meet the operating requirements, minimize the voltage, maximize the life of the anode, and to balance this against a reasonable cost for the anode. It is anticipated that after testing of the additional prototypes, a whole cell commercial test will be conducted to complete evaluation of the titanium-lead anode costs/benefits.

  11. Towards Cr(VI)-free anodization of aluminum alloys for aerospace adhesive bonding applications : A review

    NARCIS (Netherlands)

    Abrahami, S.T.; de Kok, John M.M.; Terryn, H.A.; Mol, J.M.C.

    2017-01-01

    For more than six decades, chromic acid anodizing (CAA) has been the central process in the surface pre-treatment of aluminum for adhesively bonded aircraft structures. Unfortunately, this electrolyte contains hexavalent chromium (Cr(VI)), a compound known for its toxicity and carcinogenic

  12. Effect of various de-anodizing techniques on the surface stability of non-colored and colored nanoporous AAO films in acidic solution

    Science.gov (United States)

    Awad, Ahmed M.; Shehata, Omnia S.; Heakal, Fakiha El-Taib

    2015-12-01

    Anodic aluminum oxide (AAO) is well known as an important nanostructured material, and a useful template in the fabrication of nanostructures. Nanoporous anodic alumina (PAA) with high open porosity was prepared by adopting three de-anodizing regimes following the first anodizing step and preceding the second one. The de-anodizing methods include electrolytic etching (EE) and chemical etching using either phosphoric acid (PE) or sodium hydroxide (HE) solutions. Three of the obtained AAO samples were black colored by electrodeposition of copper nanoparticles in their pores. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques were used to characterize the electrochemical performance of the two sets of the prepared samples. In general, the data obtained in aggressive aerated 0.5 M HCl solution demonstrated dissimilar behavior for the three prepared samples despite that the second anodizing step was the same for all of them. The data indicated that the resistance and thickness of the inner barrier part of nano-PAA film, are the main controlling factors determining its stability. On the other hand, coloring the film decreased its stability due to the galvanic effect. The difference in the electrochemical behavior of the three colored samples was discussed based on the difference in both the pore size and thickness of the outer porous part of PAA film as supported by SEM, TEM and cross-sectional micrographs. These results can thus contribute for better engineering applications of nanoporous AAO.

  13. Optimization of Electrochemical Treatment Process Conditions for Distillery Effluent Using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    P. Arulmathi

    2015-01-01

    Full Text Available Distillery industry is recognized as one of the most polluting industries in India with a large amount of annual effluent production. In this present study, the optimization of electrochemical treatment process variables was reported to treat the color and COD of distillery spent wash using Ti/Pt as an anode in a batch mode. Process variables such as pH, current density, electrolysis time, and electrolyte dose were selected as operation variables and chemical oxygen demand (COD and color removal efficiency were considered as response variable for optimization using response surface methodology. Indirect electrochemical-oxidation process variables were optimized using Box-Behnken response surface design (BBD. The results showed that electrochemical treatment process effectively removed the COD (89.5% and color (95.1% of the distillery industry spent wash under the optimum conditions: pH of 4.12, current density of 25.02 mA/cm2, electrolysis time of 103.27 min, and electrolyte (NaCl concentration of 1.67 g/L, respectively.

  14. Effect of nitrogen addition on the performance of microbial fuel cell anodes

    KAUST Repository

    Saito, Tomonori

    2011-01-01

    Carbon cloth anodes were modified with 4(N,N-dimethylamino)benzene diazonium tetrafluoroborate to increase nitrogen-containing functional groups at the anode surface in order to test whether the performance of microbial fuel cells (MFCs) could be improved by controllably modifying the anode surface chemistry. Anodes with the lowest extent of functionalization, based on a nitrogen/carbon ratio of 0.7 as measured by XPS, achieved the highest power density of 938mW/m2. This power density was 24% greater than an untreated anode, and similar to that obtained with an ammonia gas treatment previously shown to increase power. Increasing the nitrogen/carbon ratio to 3.8, however, decreased the power density to 707mW/m2. These results demonstrate that a small amount of nitrogen functionalization on the carbon cloth material is sufficient to enhance MFC performance, likely as a result of promoting bacterial adhesion to the surface without adversely affecting microbial viability or electron transfer to the surface. © 2010 Elsevier Ltd.

  15. Bioinspired Surface Treatments for Improved Decontamination: Fluoro-Plasma Treatment

    Science.gov (United States)

    2017-07-21

    were baked at 100°C or equilibrated to a specific relative humidity prior to collection of contact angles (Table 2). The impact of surface...No significant changes in the appearance or wetting characteristics were noted during this period. When the soapy water process was employed

  16. Surface modification of steels by electrical discharge treatment in electrolyte

    International Nuclear Information System (INIS)

    Krastev, D.; Paunov, V.; Yordanov, B.; Lazarova, V.

    2013-01-01

    Full text: In this work are discussed some experimental data about the influence of applied electrical discharge treatment in electrolyte on the surface structure of steels. The electrical discharge treatment of steel surface in electrolyte gives a modified structure with specific combination of characteristics in result of nonequilibrium transformations. The modification goes by a high energy thermal process in a very small volume on the metallic surface involving melting, vaporisation, activation and alloying in electrical discharges, and after that cooling of this surface with high rate in the electrolyte. The surface layers obtain a different structure in comparison with the metal matrix and are with higher hardness, wear resistance and corrosion resistance. key words: surface modification, electrical discharge treatment in electrolyte, steels

  17. Anodized aluminum on LDEF: A current status of measurements on chromic acid anodized aluminum

    International Nuclear Information System (INIS)

    Golden, J.L.

    1992-01-01

    Chromic acid anodize was used as the exterior coating for aluminum surfaces on LDEF to provide passive thermal control. Chromic acid anodized aluminum was also used as test specimens in thermal control coatings experiments. The following is a compilation and analysis of the data obtained thus far

  18. Anodized aluminum on LDEF: A current status of measurements on chromic acid anodized aluminum

    Science.gov (United States)

    Golden, Johnny L.

    1992-01-01

    Chromic acid anodize was used as the exterior coating for aluminum surfaces on LDEF to provide passive thermal control. Chromic acid anodized aluminum was also used as test specimens in thermal control coatings experiments. The following is a compilation and analysis of the data obtained thus far.

  19. Effect of Fe- and Si-Enriched Secondary Precipitates and Surface Roughness on Pore Formation on Aluminum Plate Surfaces During Anodizing

    Science.gov (United States)

    Zhu, Yuanzhi; Wang, Shizhi; Yang, Qingda; Zhou, Feng

    2014-09-01

    Two twin roll casts (TRCs) and one hot rolled (HR) AA 1235 aluminum alloy plates with different microstructures are prepared. The plates were electrolyzed in a 1.2 wt% HCl solution with a voltage of 21 V and a current of 1.9 mA. The shape, size, and number of pores formed on the surfaces of these plates were analyzed and correlated with the microstructures of the plates. It is found that pores are easier to form on the alloy plates containing subgrains with a lower dislocation density inside the subgrains, rather than along the grain boundaries. Furthermore, Fe- and Si-enriched particles in the AA1235 aluminum alloys lead to the formation of pores on the surface during electrolyzing; the average precipitate sizes of 4, 3.5, and 2 μm in Alloy 1#, Alloy 2# and Alloy 3# result in the average pore sizes of 3.78, 2.76, and 1.9 μm on the surfaces of the three alloys, respectively; The G.P zone in the alloy also facilitates the surface pore formation. High-surface roughness enhances the possibility of entrapping more lubricants into the plate surface, which eventually blocks the formation of the pores on the surface of the aluminum plates in the following electrolyzing process.

  20. Effects of surface treatments on the translucency, opalescence, and surface texture of dental monolithic zirconia ceramics.

    Science.gov (United States)

    Kim, Hee-Kyung; Kim, Sung-Hun; Lee, Jai-Bong; Ha, Seung-Ryong

    2016-06-01

    Surface polishing or glazing may increase the appearance of depth of monolithic zirconia restorations. The purpose of this in vitro study was to investigate the effects of surface treatments on the translucency, opalescence, and surface texture of dental monolithic zirconia ceramics. Forty-five monolithic zirconia specimens (16.3×16.4×2.0 mm) were divided into groups I to V, according to the number of colorings each received. Each group was then divided into 3 subgroups (n=3) according to the surface treatment: N=no treatment; P=polished; and G=glazed. CIElab color coordinates were obtained relative to D65 on a reflection spectrophotometer. The translucency parameter (TP) and opalescence parameter (OP) were calculated. One specimen per subgroups I and V was selected for evaluation of surface roughness (Ra) and was examined with scanning electron microscopy (SEM). Data were analyzed with 2-way ANOVA and pairwise comparisons (α=.05). Statistical powers were verified to evaluate results (α=.05). The interaction effects of surface treatments combined with the number of colorings were significant for TP, OP, and Ra (P.05), whereas glazing significantly decreased OP and Ra in most groups. SEM images demonstrated that surface treatments affected the surface texture of monolithic zirconia ceramics. Surface treatments combined with coloring strongly affect the surface texture of dental monolithic zirconia ceramics. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  1. Surface Treatment And Protection Method For Cadium Zinc Telluride Crystals

    Science.gov (United States)

    Wright, Gomez W.; James, Ralph B.; Burger, Arnold; Chinn, Douglas A.

    2006-02-21

    A method for treatment of the surface of a CdZnTe (CZT) crystal that provides a native dielectric coating to reduce surface leakage currents and thereby, improve the resolution of instruments incorporating detectors using CZT crystals. A two step process is disclosed, etching the surface of a CZT crystal with a solution of the conventional bromine/methanol etch treatment, and after attachment of electrical contacts, passivating the CZT crystal surface with a solution of 10 w/o NH4F and 10 w/o H2O2 in water.

  2. Effect of surface treatment of tailings on effluent quality

    International Nuclear Information System (INIS)

    Murray, D.R.; Okuhara, D.

    1980-01-01

    Lysimeters containing 125 tons of mine tailings were used to determine the impact of gravel, sawdust, and vegetation as surface treatments on the quality and quantity of effluent produced from sulfide-containing uranium mill tailings. Over a 5-yr period, treatments did not alter the effluent quality to a level acceptable to regulatory requirements. The concentration of iron, copper, lead, aluminum, and sulfate increased with the rise of acidity during this period. However, the rate and extent of changes did vary with the treatment. The role of surface treatment in long-term waste abandonment must be investigated further

  3. Effect of surface treatment of tailings on effluent quality

    International Nuclear Information System (INIS)

    Murray, D.R.

    1980-01-01

    Successful reclamation treatment, in preparation for long range abandonment of mining wastes, involves both surface treatment and water quality control containment of waste solids and liquid contaminants. This paper describes use of lysimeters containing 125 tonnes of tailings to determine the impact of gravel, sawdust, and vegetation as surface treatments on the quality and quantity of effluent produced from sulphide-containing uranium mill tailings. Over a five-year period these treatments were observed and compared with bare tailings where no surface addition was made. The treatments did not alter the effluent quality to a level acceptable to regulatory requirements. Surface treatments did not appear to affect the leaching of Ra-226, NH 4 and NO 3 . The concentration of Fe, SO 4 , Cu, Pb, and Al increased with the rise of acidity as the pH changed from pH 9.5 to pH 2 in four and one-half years. However the rate and extent of changes of some of these parameters vary with the treatment. The experimental results for the observed trends are presented with limited explanation. Original design problems and unexpected delays in tailing reactions have made firm conclusions impossible at this stage. These data, however, provide a base for further investigation and development of explanations and firm conclusions, as to the role of surface treatment in long-term waste abandonment

  4. Dielectric barrier discharge plasma treatment of cellulose nanofibre surfaces

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Madsen, Bo; Berglund, Linn

    2017-01-01

    on the nanofibre surface. Ultrasonic irradiation further enhanced the wetting and oxidation of the nanofibre coating. Scanning electron microscopic observations showed skeleton-like features on the plasma-treated surface, indicating preferential etching of weaker domains, such as low-molecular weight domains......Dielectric barrier discharge plasma treatment was applied to modify cellulose nanofibre (CNF) surfaces with and without ultrasonic irradiation. The plasma treatment improved the wetting by deionised water and glycerol, and increased the contents of oxygen, carbonyl group, and carboxyl group...... and amorphous phases. Ultrasonic irradiation also improved the uniformity of the treatment. Altogether, it is demonstrated that atmospheric pressure plasma treatment is a promising technique to modify the CNF surface before composite processing....

  5. Cleaning of diffusion bonding surface by argon ion bombardment treatment

    International Nuclear Information System (INIS)

    Wang, Airu; Ohashi, Osamu; Yamaguchi, Norio; Aoki, Masanori; Higashi, Yasuo; Hitomi, Nobuteru

    2003-01-01

    The specimens of oxygen-free high conductivity copper, SUS304L stainless steel and pure iron were treated by argon ion bombardment and then were bonded by diffusion bonding method. The effects of argon ion bombardment treatment on faying surface morphology, tensile strength of bonding joints and inclusions at the fracture surface were investigated. The results showed that argon ion bombardment treatment was effective to remove the oxide film and contamination at the faying surface and improve the quality of joints. The tensile strength of the bonded joints was improved, and minimum bonding temperature to make the metallic bonding at the interface was lowered by argon ion bombardment treatment. At the joints with argon ion bombardment treatment, ductile fractured surface was seen and the amount of inclusions was obviously decreased

  6. Surface treatment of nanocrystal quantum dots after film deposition

    Science.gov (United States)

    Sykora, Milan; Koposov, Alexey; Fuke, Nobuhiro

    2015-02-03

    Provided are methods of surface treatment of nanocrystal quantum dots after film deposition so as to exchange the native ligands of the quantum dots for exchange ligands that result in improvement in charge extraction from the nanocrystals.

  7. Electrooxidation as the anaerobic pre-treatment of fats: oleate conversion using RuO2 and IrO2 based anodes.

    Science.gov (United States)

    Gonçalves, M; Alves, M M; Correia, J P; Marques, I P

    2008-11-01

    Electrochemical treatment of oleate using RuO2 and IrO2 type dimensionally stable anodes in alkaline medium was performed to develop a feasible anaerobic pre-treatment of fatty effluents. The results showed that the pre-treated solutions over RuO2 were faster degraded by anaerobic consortium than the raw oleate solutions or the electrolysed solutions using IrO2. In batch experiments carried out with pre-treated solutions over RuO2 (100-500mg/L), no lag phases were observed before the methane production onset. On the other hand, raw oleate and pre-treated oleate over IrO2 had originated lag phases of 0-140 and 0-210h, respectively. This study demonstrated that it is advantageous to apply the electrochemical treatment carried out on the RuO2 type DSA in order to achieve a faster biodegradation of lipid-containing effluent and consequently to obtain a faster methane production.

  8. Development of surface decontamination technology for radioactive waste using plasma. Dust behaviors in the treatment of oxide films using a low-pressure arc

    International Nuclear Information System (INIS)

    Adachi, Kazuo; Furukawa, Shizue; Amakawa, Tadashi; Fujiwara, Kazutoshi; Kanbe, Hiromu

    2002-01-01

    We are developing the surface treatment technique using low-pressure arc as a new decontamination technology for radioactive wastes from nuclear facilities. For the practical use, effective dust collection methods are necessary, because dust is generated from oxide films on the surface during the treatment. The method using gas stream and filters may be one of them, but the behavior of the dust has not been examined yet. We studied the basic behavior of the dust and the possibilities of dust control by gas stream as follows. 1. Most of the dust attached to the anode in the case of no gas blow. 2. Dust attachment to the anode was reduced to about half using small cross section type anode. It seems to be possible to reduce the dust attachment by proper choice of electrode shape. 3. The dust attachment was reduced to 10 to 40 percent by the gas blow to the side of arc. The dust control by gas stream might be possible. (author)

  9. The effects of surface treatments on rapid chloride permeability tests

    KAUST Repository

    Yoon, Seyoon

    2012-08-01

    Surface treatments are commonly applied to improve the chloride resistance of concrete structures exposed to saline environments. Information on chloride ingress to surface-treated concrete is mostly provided by application of the rapid chloride permeability test (RCPT); this test is short in duration and provides rapid results. This study presents a numerical formulation, based on the extended Nernst-Plank/Poisson (NPP) equation, to model the effect of the surface treatment on a sample tested by RCPT. Predictions of the model are compared to experimental measurements. The simulations show that the results from RCPT, in terms of ionic profiles and measurement of the electric field, are dependent on the effectiveness of surface treatments. During RCPT, highly effective surface treatments cause both cations and anions to flocculate at the interface between the surface treatment and the concrete, creating a local electric field. Our numerical model includes these phenomena and presents a methodology to obtain more accurate diffusivities of the surface-treated- concrete from RCPT. © 2012 Elsevier B.V. All rights reserved.

  10. The effects of surface treatments on rapid chloride permeability tests

    KAUST Repository

    Yoon, Seyoon; Oh, Sang-gyun; Ha, Juyoung; Monteiro, Paulo M.

    2012-01-01

    Surface treatments are commonly applied to improve the chloride resistance of concrete structures exposed to saline environments. Information on chloride ingress to surface-treated concrete is mostly provided by application of the rapid chloride permeability test (RCPT); this test is short in duration and provides rapid results. This study presents a numerical formulation, based on the extended Nernst-Plank/Poisson (NPP) equation, to model the effect of the surface treatment on a sample tested by RCPT. Predictions of the model are compared to experimental measurements. The simulations show that the results from RCPT, in terms of ionic profiles and measurement of the electric field, are dependent on the effectiveness of surface treatments. During RCPT, highly effective surface treatments cause both cations and anions to flocculate at the interface between the surface treatment and the concrete, creating a local electric field. Our numerical model includes these phenomena and presents a methodology to obtain more accurate diffusivities of the surface-treated- concrete from RCPT. © 2012 Elsevier B.V. All rights reserved.

  11. Treatment of polymer surfaces in plasma Part I. Kinetic model

    International Nuclear Information System (INIS)

    Tabaliov, N A; Svirachev, D M

    2006-01-01

    The surface tension of the polymer materials depends on functional groups over its surface. As a result from the plasma treatment the kind and concentration of the functional groups can be changed. In the present work, the possible kinetic reactions are defined. They describe the interaction between the plasma and the polymer surface of polyethylene terephthalate (PET). Basing on these reactions, the systems of differential kinetic equations are suggested. The solutions are obtained analytically for the system kinetic equations at defined circumstances

  12. Structural Engineering of Nanoporous Anodic Alumina Photonic Crystals by Sawtooth-like Pulse Anodization.

    Science.gov (United States)

    Law, Cheryl Suwen; Santos, Abel; Nemati, Mahdieh; Losic, Dusan

    2016-06-01

    This study presents a sawtooth-like pulse anodization approach aiming to create a new type of photonic crystal structure based on nanoporous anodic alumina. This nanofabrication approach enables the engineering of the effective medium of nanoporous anodic alumina in a sawtooth-like manner with precision. The manipulation of various anodization parameters such as anodization period, anodization amplitude, number of anodization pulses, ramp ratio and pore widening time allows a precise control and fine-tuning of the optical properties (i.e., characteristic transmission peaks and interferometric colors) exhibited by nanoporous anodic alumina photonic crystals (NAA-PCs). The effect of these anodization parameters on the photonic properties of NAA-PCs is systematically evaluated for the establishment of a fabrication methodology toward NAA-PCs with tunable optical properties. The effective medium of the resulting NAA-PCs is demonstrated to be optimal for the development of optical sensing platforms in combination with reflectometric interference spectroscopy (RIfS). This application is demonstrated by monitoring in real-time the formation of monolayers of thiol molecules (11-mercaptoundecanoic acid) on the surface of gold-coated NAA-PCs. The obtained results reveal that the adsorption mechanism between thiol molecules and gold-coated NAA-PCs follows a Langmuir isotherm model, indicating a monolayer sorption mechanism.

  13. Surface pre-treatment for barrier coatings on polyethylene terephthalate

    Science.gov (United States)

    Bahre, H.; Bahroun, K.; Behm, H.; Steves, S.; Awakowicz, P.; Böke, M.; Hopmann, Ch; Winter, J.

    2013-02-01

    Polymers have favourable properties such as light weight, flexibility and transparency. Consequently, this makes them suitable for food packaging, organic light-emitting diodes and flexible solar cells. Nonetheless, raw plastics do not possess sufficient barrier functionality against oxygen and water vapour, which is of paramount importance for most applications. A widespread solution is to deposit thin silicon oxide layers using plasma processes. However, silicon oxide layers do not always fulfil the requirements concerning adhesion and barrier performance when deposited on films. Thus, plasma pre-treatment is often necessary. To analyse the influence of a plasma-based pre-treatment on barrier performance, different plasma pre-treatments on three reactor setups were applied to a very smooth polyethylene terephthalate film before depositing a silicon oxide barrier layer. In this paper, the influence of oxygen and argon plasma pre-treatments towards the barrier performance is discussed examining the chemical and topological change of the film. It was observed that a short one-to-ten-second plasma treatment can reduce the oxygen transmission rate by a factor of five. The surface chemistry and the surface topography change significantly for these short treatment times, leading to an increased surface energy. The surface roughness rises slowly due to the development of small spots in the nanometre range. For very long treatment times, surface roughness of the order of the barrier layer's thickness results in a complete loss of barrier properties. During plasma pre-treatment, the trade-off between surface activation and roughening of the surface has to be carefully considered.

  14. Surface pre-treatment for barrier coatings on polyethylene terephthalate

    International Nuclear Information System (INIS)

    Bahre, H; Böke, M; Winter, J; Bahroun, K; Behm, H; Hopmann, Ch; Steves, S; Awakowicz, P

    2013-01-01

    Polymers have favourable properties such as light weight, flexibility and transparency. Consequently, this makes them suitable for food packaging, organic light-emitting diodes and flexible solar cells. Nonetheless, raw plastics do not possess sufficient barrier functionality against oxygen and water vapour, which is of paramount importance for most applications. A widespread solution is to deposit thin silicon oxide layers using plasma processes. However, silicon oxide layers do not always fulfil the requirements concerning adhesion and barrier performance when deposited on films. Thus, plasma pre-treatment is often necessary. To analyse the influence of a plasma-based pre-treatment on barrier performance, different plasma pre-treatments on three reactor setups were applied to a very smooth polyethylene terephthalate film before depositing a silicon oxide barrier layer. In this paper, the influence of oxygen and argon plasma pre-treatments towards the barrier performance is discussed examining the chemical and topological change of the film. It was observed that a short one-to-ten-second plasma treatment can reduce the oxygen transmission rate by a factor of five. The surface chemistry and the surface topography change significantly for these short treatment times, leading to an increased surface energy. The surface roughness rises slowly due to the development of small spots in the nanometre range. For very long treatment times, surface roughness of the order of the barrier layer's thickness results in a complete loss of barrier properties. During plasma pre-treatment, the trade-off between surface activation and roughening of the surface has to be carefully considered. (paper)

  15. A new, high energy rechargeable lithium ion battery with a surface-treated Li1.2Mn0.54Ni0.13Co0.13O2 cathode and a nano-structured Li4Ti5O12 anode

    International Nuclear Information System (INIS)

    Liu, Xiaoyu; Huang, Tao; Yu, Aishui

    2015-01-01

    Through elaborate design, a new rechargeable lithium ion battery has been developed by comprising a surface-treated Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 cathode and a nano-structured Li 4 Ti 5 O 12 anode. After precondition Na 2 S 2 O 8 treatment, the initial coulombic efficiency of Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 cathode has been significantly increased and can be compatible with that of the nano-structured Li 4 Ti 5 O 12 anode. The optimization of structure and morphology for both active electrode materials result in their remarkable electrochemical performances in respective lithium half-cells. Ultimately, the rechargeable lithium ion full battery consisting of both electrodes delivers a specific capacity of 99.0 mAh g −1 and a practical energy density of 201 Wh kg −1 , based on the total weight of both active electrode materials. Furthermore, as a promising candidate in the lithium ion battery field, this full battery also achieves highly attractive electrochemical performance with high coulombic efficiency, excellent cycling stability and outstanding rate capability. Thus the proposed battery displays broad practical application prospects for next generation of high-energy lithium ion battery. - Highlights: • The Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 cathode is surface-treated by Na 2 S 2 O 8 . • The nano-sized Li 4 Ti 5 O 12 anode is obtained by a solid-state method. • A new Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 /Li 4 Ti 5 O 12 lithium ion battery is developed. • The battery shows high coulombic efficiency, specific capacity and energy density. • The battery shows high capacity retention rate and good high-rate capability

  16. Analysis of the Surface of Deposited Copper After Electroerosion Treatment

    Science.gov (United States)

    Ablyaz, T. R.; Simonov, M. Yu.; Shlykov, E. S.

    2018-03-01

    An electron microscope analysis of the surface of deposited copper is performed after a profiling-piercing electroerosion treatment. The deposited copper is treated with steel, duralumin, and copper electrode tools at different pulse energies. The treatment with the duralumin electrode produces on the treated surface a web-like structure and cubic-morphology polyhedral dimples about 10 μm in size. The main components of the surface treated with the steel electrode are developed polyhedral dimples with a size of 10 - 50 μm. After the treatment with the copper electrode the main components of the treated surface are large polyhedral dimples about 30 - 80 μm in size.

  17. Improvement of crystalline silicon surface passivation by hydrogen plasma treatment

    International Nuclear Information System (INIS)

    Martin, I.; Vetter, M.; Orpella, A.; Voz, C.; Puigdollers, J.; Alcubilla, R.; Kharchenko, A.V.; Roca i Cabarrocas, P.

    2004-01-01

    A completely dry low-temperature process has been developed to passivate 3.3 Ω cm p-type crystalline silicon surface with excellent results. Particularly, we have investigated the use of a hydrogen plasma treatment, just before hydrogenated amorphous silicon carbide (a-SiC x :H) deposition, without breaking the vacuum. We measured effective lifetime, τ eff , through a quasi-steady-state photoconductance technique. Experimental results show that hydrogen plasma treatment improves surface passivation compared to classical HF dip. S eff values lower than 19 cm s -1 were achieved using a hydrogen plasma treatment and an a-SiC x :H film deposited at 300 deg. C

  18. PITTING CORROSION OF STAINLESS STEEL AT THE VARIOUS SURFACE TREATMENT

    Directory of Open Access Journals (Sweden)

    Viera Zatkalíková

    2011-09-01

    Full Text Available The stainless steel surface treatment is very important with regard to its pitting corrosion susceptibility. An effect of various types surfacing on pitting corrosion resistance of AISI 304stainless steel is investigated in this work. The samples of the tested material are turned, blasted, peened, grinded and a half of them are pickled to achieve higher purity of surfaces and better quality of passive film. Eight types of different finished surfaces are tested by electrochemical and immersion tests to determine corrosion behaviour in conditions where pitting is evoked by controlled potential and second by solution with high redox potential. By this way the effect of mechanical and chemical surface treatment on the resistance to pitting corrosion, character, size and shape of pits are compared in the conditions of different mechanisms of corrosion process.

  19. On the role of salts for the treatment of wastewaters containing pharmaceuticals by electrochemical oxidation using a boron doped diamond anode

    International Nuclear Information System (INIS)

    Lan, Yandi; Coetsier, Clémence; Causserand, Christel; Groenen Serrano, Karine

    2017-01-01

    Refractory pharmaceuticals remain in biologically treated wastewater and are continuously discharged into aquatic systems due to their limited biodegradability. Electrochemical oxidation is promising for the treatment of such refractory compounds, in particular using a boron doped diamond (BDD) anode. This study investigates the role of salts, such as sulfates and chlorides in the electrochemical treatment of wastewater. The presence of sulfates accelerated the removal of ciprofloxacin and sulfamethoxazole, but had no effect on the oxidation of salbutamol. This comparison highlights the selectivity of the reaction between organics and sulfate radicals. The addition of chlorides into the solution led to a remarkably-faster degradation of ciprofloxacin. However, incomplete mineralization was observed at high current densities due to the significant formation of halogenated organic compounds (AOX). The formation of refractory and toxic compounds such as ClO_4"− and AOX can be limited under the control of (i) applied current intensity and (ii) duration of electrolysis. Electrochemical oxidation of concentrated biologically-treated hospital wastewater investigated the excellent removal of biorefractory pharmaceuticals and confirmed the acceleration effect of salts on pharmaceutical degradation.

  20. Numerical treatment of free surface problems in ferrohydrodynamics

    International Nuclear Information System (INIS)

    Lavrova, O; Matthies, G; Mitkova, T; Polevikov, V; Tobiska, L

    2006-01-01

    The numerical treatment of free surface problems in ferrohydrodynamics is considered. Starting from the general model, special attention is paid to field-surface and flow-surface interactions. Since in some situations these feedback interactions can be partly or even fully neglected, simpler models can be derived. The application of such models to the numerical simulation of dissipative systems, rotary shaft seals, equilibrium shapes of ferrofluid drops, and pattern formation in the normal-field instability of ferrofluid layers is given. Our numerical strategy is able to recover solitary surface patterns which were discovered recently in experiments

  1. Lithium Ion Battery Anode Aging Mechanisms

    Science.gov (United States)

    Agubra, Victor; Fergus, Jeffrey

    2013-01-01

    Degradation mechanisms such as lithium plating, growth of the passivated surface film layer on the electrodes and loss of both recyclable lithium ions and electrode material adversely affect the longevity of the lithium ion battery. The anode electrode is very vulnerable to these degradation mechanisms. In this paper, the most common aging mechanisms occurring at the anode during the operation of the lithium battery, as well as some approaches for minimizing the degradation are reviewed. PMID:28809211

  2. Treatment of carbon fiber brush anodes for improving power generation in air–cathode microbial fuel cells

    KAUST Repository

    Feng, Yujie; Yang, Qiao; Wang, Xin; Logan, Bruce E.

    2010-01-01

    -AH). The combined heat and acid treatment improve power production to 1370 mW m-2, which is 34% larger than the untreated control (CF-C, 1020 mW m-2). This power density is 25% higher than using only acid treatment (1100 mW m-2) and 7% higher than that using only

  3. Effect of current density and behaviour of second phases in anodizing of a Mg-Zn-RE alloy in a fluoride/glycerol/water electrolyte

    Czech Academy of Sciences Publication Activity Database

    Němcová, A.; Kuběna, Ivo; Šmíd, Miroslav; Habazaki, H.; Skeldon, P.; Thompson, G.

    2016-01-01

    Roč. 20, č. 4 (2016), s. 1155-1165 ISSN 1432-8488 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : magnesium * anodizing * anodic film * TEM * RBS Subject RIV: JK - Corrosion ; Surface Treatment of Materials Impact factor: 2.316, year: 2016 http://link.springer.com/article/10.1007/s10008-015-2864-1

  4. Anodizing color coded anodized Ti6Al4V medical devices for increasing bone cell functions

    Directory of Open Access Journals (Sweden)

    Webster TJ

    2013-01-01

    Full Text Available Alexandra P Ross, Thomas J WebsterSchool of Engineering and Department of Orthopedics, Brown University, Providence, RI, USAAbstract: Current titanium-based implants are often anodized in sulfuric acid (H2SO4 for color coding purposes. However, a crucial parameter in selecting the material for an orthopedic implant is the degree to which it will integrate into the surrounding bone. Loosening at the bone–implant interface can cause catastrophic failure when motion occurs between the implant and the surrounding bone. Recently, a different anodization process using hydrofluoric acid has been shown to increase bone growth on commercially pure titanium and titanium alloys through the creation of nanotubes. The objective of this study was to compare, for the first time, the influence of anodizing a titanium alloy medical device in sulfuric acid for color coding purposes, as is done in the orthopedic implant industry, followed by anodizing the device in hydrofluoric acid to implement nanotubes. Specifically, Ti6Al4V model implant samples were anodized first with sulfuric acid to create color-coding features, and then with hydrofluoric acid to implement surface features to enhance osteoblast functions. The material surfaces were characterized by visual inspection, scanning electron microscopy, contact angle measurements, and energy dispersive spectroscopy. Human osteoblasts were seeded onto the samples for a series of time points and were measured for adhesion and proliferation. After 1 and 2 weeks, the levels of alkaline phosphatase activity and calcium deposition were measured to assess the long-term differentiation of osteoblasts into the calcium depositing cells. The results showed that anodizing in hydrofluoric acid after anodizing in sulfuric acid partially retains color coding and creates unique surface features to increase osteoblast adhesion, proliferation, alkaline phosphatase activity, and calcium deposition. In this manner, this study

  5. Methods for making anodes for lithium ion batteries

    Science.gov (United States)

    Xu, Wu; Canfield, Nathan L.; Zhang, Ji-Guang; Liu, Wei; Xiao, Jie; Wang, Deyu; Yang, Z. Gary

    2015-05-26

    Methods for making composite anodes, such as macroporous composite anodes, are disclosed. Embodiments of the methods may include forming a tape from a slurry including a substrate metal precursor, an anode active material, a pore-forming agent, a binder, and a solvent. A laminated structure may be prepared from the tape and sintered to produce a porous structure, such as a macroporous structure. The macroporous structure may be heated to reduce a substrate metal precursor and/or anode active material. Macroporous composite anodes formed by some embodiments of the disclosed methods comprise a porous metal and an anode active material, wherein the anode active material is both externally and internally incorporated throughout and on the surface of the macroporous structure.

  6. Theme day: corrosion and surface treatments in nuclear facilities. Proceedings

    International Nuclear Information System (INIS)

    2012-02-01

    This document brings together the available presentations given at the theme day organized by the Bourgogne Nuclear Pole on the topic of corrosion and surface treatments in nuclear facilities. Eleven presentations (slides) are compiled in this document: 1 - Introduction - PNB centre of competitiveness and R and D activities (A. Mantovan, PNB); 2 - Corrosion damage (M. Foucault, Areva NP - Centre Technique Le Creusot); 3 - Corrosion mechanisms (R. Oltra, UB-ICB); 4 - Examples of expertise management (C. Duret-Thual, Institut de la corrosion/Corrosion Institute); 5 - General framework of surface treatments (C. Nouveau, ENSAM Cluny Paris Tech); 6 - Surfaces et interfaces characterisation - Part A (C. Langlade, Y. Gachon, UTBM and HEF); 7 - Surfaces et interfaces characterisation - Part B (C. Langlade, Y. Gachon, UTBM and HEF); 8 - Ion beam surface treatment (Y. Le Guellec, Quertech Ingenierie); 9 - Impact surface treatment (G. Saout, Sonats); 10 - Metal oxides Characterisation by US laser (R. Oltra, UB-ICB); 11 - Detection and Characterisation of intergranular corrosion (Y. Kernin, Stephane Bourgois, Areva Intercontrole)

  7. Study on hydrophilicity of polymer surfaces improved by plasma treatment

    International Nuclear Information System (INIS)

    Lai Jiangnan; Sunderland, Bob; Xue Jianming; Yan, Sha; Zhao Weijiang; Folkard, Melvyn; Michael, Barry D.; Wang Yugang

    2006-01-01

    Surface properties of polycarbonate (PC), polypropylene (PP), polyethylene terephthalate (PET) samples treated by microwave-induced argon plasma have been studied with contact angle measurement, X-ray photoelectron spectroscopy (XPS) and scanned electron microscopy (SEM). It is found that plasma treatment modified the surfaces both in composition and roughness. Modification of composition makes polymer surfaces tend to be highly hydrophilic, which mainly depended on the increase of ratio of oxygen-containing group as same as other papers reported. And this experiment further revealed that C=O bond is Key factor to the improvement of the hydrophilicity of polymer surfaces. Our SEM observation on PET shown that the roughness of the surface has also been improved in micron scale and it has influence on the surface hydrophilicity

  8. Surface oxide formation during corona discharge treatment of AA 1050 aluminium surfaces

    DEFF Research Database (Denmark)

    Minzari, Daniel; Møller, Per; Kingshott, Peter

    2008-01-01

    process modifies aluminium AA 1050 surface, the oxide growth and resulting corrosion properties. The corona treatment is carried out in atmospheric air. Treated surfaces are characterized using XPS, SEM/EDS, and FIB-FESEM and results suggest that an oxide layer is grown, consisting of mixture of oxide...

  9. Low voltage aluminium anodes. Optimization of the insert-anode bond

    Energy Technology Data Exchange (ETDEWEB)

    Le Guyader, Herve; Debout, Valerie; Grolleau, Anne-Marie [DCN Cherbourg, Departement 2EI, Place Bruat, BP 440, 50104 Cherbourg-Octeville (France); Pautasso, Jean-Pierre [DGA/CTA 16 bis, avenue Prieur de la Cote D' Or, 94 114 Arcueil Cedex (France)

    2004-07-01

    shape of the insert, chemical bonds using bimetallic materials, heat treatment such as hot isostatic pressing, use of tube inserts. Final selections were made using toughened cyclic pressure tests in natural sea water associated with metallurgical examinations. The experimental feedback after more than 5 years of operation is given and demonstrate that adequate protection is achieved provided that good anode-insert continuity is kept. Both the sacrificial alloy itself and the new anode design have proved to be successful. (authors)

  10. Ellipsometry of anodic film growth

    Energy Technology Data Exchange (ETDEWEB)

    Smith, C.G.

    1978-08-01

    An automated computer interpretation of ellisometer measurements of anodic film growth was developed. Continuous mass and charge balances were used to utilize more fully the time dependence of the ellipsometer data and the current and potential measurements. A multiple-film model was used to characterize the growth of films which proceeds via a dissolution--precipitation mechanism; the model also applies to film growth by adsorption and nucleation mechanisms. The characteristic parameters for film growth describe homogeneous and heterogeneous crystallization rates, film porosities and degree of hydration, and the supersaturation of ionic species in the electrolyte. Additional descriptions which may be chosen are patchwise film formation, nonstoichiometry of the anodic film, and statistical variations in the size and orientation of secondary crystals. Theories were developed to describe the optical effects of these processes. An automatic, self-compensating ellipsometer was used to study the growth in alkaline solution of anodic films on silver, cadmium, and zinc. Mass-transport conditions included stagnant electrolyte and forced convection in a flow channel. Multiple films were needed to characterize the optical properties of these films. Anodic films grew from an electrolyte supersatuated in the solution-phase dissolution product. The degree of supersaturation depended on transport conditions and had a major effect on the structure of the film. Anodic reaction rates were limited by the transport of charge carriers through a primary surface layer. The primary layers on silver, zinc, and cadmium all appeared to be nonstoichiometric, containing excess metal. Diffusion coefficients, transference numbers, and the free energy of adsorption of zinc oxide were derived from ellipsometer measurements. 97 figures, 13 tables, 198 references.

  11. Carbonate fuel cell anodes

    Science.gov (United States)

    Donado, Rafael A.; Hrdina, Kenneth E.; Remick, Robert J.

    1993-01-01

    A molten alkali metal carbonates fuel cell porous anode of lithium ferrite and a metal or metal alloy of nickel, cobalt, nickel/iron, cobalt/iron, nickel/iron/aluminum, cobalt/iron/aluminum and mixtures thereof wherein the total iron content including ferrite and iron of the composite is about 25 to about 80 percent, based upon the total anode, provided aluminum when present is less than about 5 weight percent of the anode. A process for production of the lithium ferrite containing anode by slipcasting.

  12. Surface improvement of EPDM rubber by plasma treatment

    Energy Technology Data Exchange (ETDEWEB)

    Moraes, J H [LPP, Physics Department, ITA, CTA, Pca Mal Eduardo Gomes 50, 12228-900 Sao Jose dos Campos, S.P. (Brazil); Silva Sobrinho, A S da [LPP, Physics Department, ITA, CTA, Pca Mal Eduardo Gomes 50, 12228-900 Sao Jose dos Campos, S.P. (Brazil); Maciel, H S [LPP, Physics Department, ITA, CTA, Pca Mal Eduardo Gomes 50, 12228-900 Sao Jose dos Campos, S.P. (Brazil); Dutra, J C N [EBO, Chemistry Division, IAE, CTA, Pca Mal Eduardo Gomes 50, 12228-904 Sao Jose dos Campos, S.P. (Brazil); Massi, M [LPP, Physics Department, ITA, CTA, Pca Mal Eduardo Gomes 50, 12228-900 Sao Jose dos Campos, S.P. (Brazil); Mello, S A C [EBO, Chemistry Division, IAE, CTA, Pca Mal Eduardo Gomes 50, 12228-904 Sao Jose dos Campos, S.P. (Brazil); Schreiner, W H [Physics Department, UFPR, Centro Politecnico, 80060-000 Curitiba, P.R. (Brazil)

    2007-12-21

    The surface of ethylene-propylene-diene monomer (EPDM) rubber was treated in N{sub 2}/Ar and N{sub 2}/H{sub 2}/Ar RF plasmas in order to achieve similar or better adhesion properties than NBR (acrylonitrile-butadiene) rubber, nowadays used as thermal protection of rocket chambers. The surface properties were studied by contact angle measurements and by x-ray photoelectron spectroscopy (XPS). The treated surfaces of the EPDM samples show a significant reduction in the contact angle measurement, indicating an increase in the surface energy. XPS analyses show the incorporation of polar nitrogen- and oxygen-containing groups on the rubber surface. After plasma treatment the presence of oxygen is observed due to surface oxidation which occurs when the samples are exposed to the air. Atomic force microscopy and scanning electron microscopy analyses indicate a decrease in the EPDM rubber surface roughness, promoted by surface etching during the plasma treatment. Strength tests indicate improvement of about 30% and 110% in the adhesion strength for the plasma treated EPDM/polyurethane liner interface and for the EPDM/epoxy adhesive interface, respectively. The adhesion strength of the EPDM/liner is similar to that obtained for the NBR/liner, which indicates that EPDM rubber can safely be used as thermal protection of the solid propellant rocket chamber.

  13. Surface improvement of EPDM rubber by plasma treatment

    International Nuclear Information System (INIS)

    Moraes, J H; Silva Sobrinho, A S da; Maciel, H S; Dutra, J C N; Massi, M; Mello, S A C; Schreiner, W H

    2007-01-01

    The surface of ethylene-propylene-diene monomer (EPDM) rubber was treated in N 2 /Ar and N 2 /H 2 /Ar RF plasmas in order to achieve similar or better adhesion properties than NBR (acrylonitrile-butadiene) rubber, nowadays used as thermal protection of rocket chambers. The surface properties were studied by contact angle measurements and by x-ray photoelectron spectroscopy (XPS). The treated surfaces of the EPDM samples show a significant reduction in the contact angle measurement, indicating an increase in the surface energy. XPS analyses show the incorporation of polar nitrogen- and oxygen-containing groups on the rubber surface. After plasma treatment the presence of oxygen is observed due to surface oxidation which occurs when the samples are exposed to the air. Atomic force microscopy and scanning electron microscopy analyses indicate a decrease in the EPDM rubber surface roughness, promoted by surface etching during the plasma treatment. Strength tests indicate improvement of about 30% and 110% in the adhesion strength for the plasma treated EPDM/polyurethane liner interface and for the EPDM/epoxy adhesive interface, respectively. The adhesion strength of the EPDM/liner is similar to that obtained for the NBR/liner, which indicates that EPDM rubber can safely be used as thermal protection of the solid propellant rocket chamber

  14. Surface improvement of EPDM rubber by plasma treatment

    Science.gov (United States)

    Moraes, J. H.; da Silva Sobrinho, A. S.; Maciel, H. S.; Dutra, J. C. N.; Massi, M.; Mello, S. A. C.; Schreiner, W. H.

    2007-12-01

    The surface of ethylene-propylene-diene monomer (EPDM) rubber was treated in N2/Ar and N2/H2/Ar RF plasmas in order to achieve similar or better adhesion properties than NBR (acrylonitrile-butadiene) rubber, nowadays used as thermal protection of rocket chambers. The surface properties were studied by contact angle measurements and by x-ray photoelectron spectroscopy (XPS). The treated surfaces of the EPDM samples show a significant reduction in the contact angle measurement, indicating an increase in the surface energy. XPS analyses show the incorporation of polar nitrogen- and oxygen-containing groups on the rubber surface. After plasma treatment the presence of oxygen is observed due to surface oxidation which occurs when the samples are exposed to the air. Atomic force microscopy and scanning electron microscopy analyses indicate a decrease in the EPDM rubber surface roughness, promoted by surface etching during the plasma treatment. Strength tests indicate improvement of about 30% and 110% in the adhesion strength for the plasma treated EPDM/polyurethane liner interface and for the EPDM/epoxy adhesive interface, respectively. The adhesion strength of the EPDM/liner is similar to that obtained for the NBR/liner, which indicates that EPDM rubber can safely be used as thermal protection of the solid propellant rocket chamber.

  15. The morphology of coconut fiber surface under chemical treatment

    OpenAIRE

    Arsyad, Muhammad; Wardana, I Nyoman Gede; Pratikto,; Irawan, Yudy Surya

    2015-01-01

    The objective of this study was to determine the effect of chemical treatment on the coconut fiber surface morphology. This study is divided into three stages, preparation of materials, treatment and testing of coconut fiber. The first treatment is coconut fiber soaked in a solution of NaOH for 3 hours with concentration, respectively 5%, 10%, 15%, and 20%. The second treatment is coconut fiber soaked in KMnO4 solution with a concentration of 0.25%, 0.5%, 0.75%, and 1% for 3 hours. The third ...

  16. Formation of macroscopic surface layers on Fe(0) electrocoagulation electrodes during an extended field trial of arsenic treatment.

    Science.gov (United States)

    van Genuchten, Case M; Bandaru, Siva R S; Surorova, Elena; Amrose, Susan E; Gadgil, Ashok J; Peña, Jasquelin

    2016-06-01

    Extended field trials to remove arsenic (As) via Fe(0) electrocoagulation (EC) have demonstrated consistent As removal from groundwater to concentrations below 10 μg L(-1). However, the coulombic performance of long-term EC field operation is lower than that of laboratory-based systems. Although EC electrodes used over prolonged periods show distinct passivation layers, which have been linked to decreased treatment efficiency, the spatial distribution and mineralogy of such surface layers have not been investigated. In this work, we combine wet chemical measurements with sub-micron-scale chemical maps and selected area electron diffraction (SAED) to determine the chemical composition and mineral phase of surface layers formed during long-term Fe(0) EC treatment. We analyzed Fe(0) EC electrodes used for 3.5 months of daily treatment of As-contaminated groundwater in rural West Bengal, India. We found that the several mm thick layer that formed on cathodes and anodes consisted of primarily magnetite, with minor fractions of goethite. Spatially-resolved SAED patterns also revealed small quantities of CaCO3, Mn oxides, and SiO2, the source of which was the groundwater electrolyte. We propose that the formation of the surface layer contributes to decreased treatment performance by preventing the migration of EC-generated Fe(II) to the bulk electrolyte, where As removal occurs. The trapped Fe(II) subsequently increases the surface layer size at the expense of treatment efficiency. Based on these findings, we discuss several simple and affordable methods to prevent the efficiency loss due to the surface layer, including alternating polarity cycles and cleaning the Fe(0) surface mechanically or via electrolyte scouring. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Stainless steel anodes for alkaline water electrolysis and methods of making

    Science.gov (United States)

    Soloveichik, Grigorii Lev

    2014-01-21

    The corrosion resistance of stainless steel anodes for use in alkaline water electrolysis was increased by immersion of the stainless steel anode into a caustic solution prior to electrolysis. Also disclosed herein are electrolyzers employing the so-treated stainless steel anodes. The pre-treatment process provides a stainless steel anode that has a higher corrosion resistance than an untreated stainless steel anode of the same composition.

  18. Surface Modification of Polymeric Materials by Plasma Treatment

    Directory of Open Access Journals (Sweden)

    E.F. Castro Vidaurre

    2002-03-01

    Full Text Available Low-temperature plasma treatment has been used in the last years as a useful tool to modify the surface properties of different materials, in special of polymers. In the present work low temperature plasma was used to treat the surface of asymmetric porous substrates of polysulfone (PSf membranes. The main purpose of this work was to study the influence of the exposure time and the power supplied to argon plasma on the permeability properties of the membranes. Three rf power levels, respectively 5, 10 and 15 W were used. Treatment time ranged from 1 to 50 min. Reduction of single gas permeability was observed with Ar plasma treatments at low energy bombardment (5 W and short exposure time (20 min. Higher power and/or higher plasma exposition time causes a degradation process begins. The chemical and structural characterization of the membranes before and after the surface modification was done by AFM, SEM and XPS.

  19. Surface treatment of reinforced cement concrete mixtures of hpcm type

    OpenAIRE

    Vyrozhemsky, V.; Krayushkina, K.

    2006-01-01

    One of the most perspective ways of pavement roughness and durability improvement is the arrangement of thin cement concrete layer surface treatment reinforced with different types of fiber. The name of this material is known abroad as HPCM (High Performance Cementious Materials) durable thin layer concrete pavement in a thickness of 1 cm, dispersion-like reinforced with metal or polymer fibers. To enhance bind properties the stone material grade 3 7mm is applied on the top of concrete surfac...

  20. Square-wave anodic-stripping voltammetric determination of Cd, Pb and Cu in wine: Set-up and optimization of sample pre-treatment and instrumental parameters

    International Nuclear Information System (INIS)

    Illuminati, Silvia; Annibaldi, Anna; Truzzi, Cristina; Finale, Carolina; Scarponi, Giuseppe

    2013-01-01

    For the first time, square-wave anodic-stripping voltammetry (SWASV) was set up and optimized for the determination of Cd, Pb and Cu in white wine after UV photo-oxidative digestion of the sample. The best procedure for the sample pre-treatment consisted in a 6-h UV irradiation of diluted, acidified wine, with the addition of ultrapure H 2 O 2 (three sequential additions during the irradiation). Due to metal concentration differences, separate measurements were carried out for Cd (deposition potential −950 mV vs. Ag/AgCl/3 M KCl deposition time 15 min) and simultaneously for Pb and Cu (E d −750 mV, t d 30 s). The optimum set-up of the main instrumental parameters, evaluated also in terms of the signal-to-noise ratio, were as follows: E SW 20 mV, f 100 Hz, ΔE step 8 mV, t step 100 ms, t wait 60 ms, t delay 2 ms, t meas 3 ms. The electrochemical behaviour was reversible bielectronic for Cd and Pb, and kinetically controlled monoelectronic for Cu. Good accuracy was found both when the recovery procedure was used and when the results were compared with data obtained by differential pulse anodic stripping voltammetry. The linearity of the response was verified up to ∼4 μg L −1 for Cd and Pb and ∼15 μg L −1 for Cu. The detection limits for t d = 5 min in the 10 times diluted, UV digested sample were (ng L −1 ): Cd 7.0, Pb 1.2 and Cu 6.6, which are well below currently applied methods. Application to a Verdicchio dei Castelli di Jesi white wine revealed concentration levels of Cd ∼0.2, Pb ∼10, Cu ∼30 μg L −1 with repeatabilities of (±RSD%) Cd ±6%, Pb ±5%, Cu ±10%

  1. Ion beam surface treatment: A new capability for rapid melt and resolidification of surfaces

    International Nuclear Information System (INIS)

    Stinnett, R.W.; McIntyre, D.C.; Buchheit, R.G.; Greenly, J.B.; Thompson, M.O.

    1994-01-01

    The emerging capability to produce high average power (5--250 kW) pulsed ion beams at 0.2--2 MeV energies is enabling us to develop a new, commercial-scale thermal surface treatment technology called Ion Beam Surface Treatment (IBEST). This technique uses high energy, pulsed (≤100 ns) ion beams to directly deposit energy in the top 2--20 micrometers of the surface of any material. Depth of treatment is controllable by varying the ion energy and species. Deposition of the energy with short pulses in a thin surface layer allows melting of the layer with relatively small energies and allows rapid cooling of the melted layer by thermal diffusion into the underlying substrate. Typical cooling rates of this process (10 9 10 10 K/sec) cause rapid resolidification, resulting in production of non-equilibrium microstructures (nano-crystalline and metastable phases) that have significantly improved corrosion, wear, and hardness properties. We have conducted IBEST feasibility experiments with results confirming surface hardening, nanocrystaline grain formation, metal surface polishing, controlled melt of ceramic surfaces, and surface cleaning

  2. HIGH VELOCITY THERMAL GUN FOR SURFACE PREPARATION AND TREATMENT

    Directory of Open Access Journals (Sweden)

    I.A. Gorlach

    2012-01-01

    Full Text Available Many surface preparation and treatment processes utilise compressed air to propel particles against surfaces in order to clean and treat them. The effectiveness of the processes depends on the velocity of the particles, which in turn depends on the pressure of the compressed air. This paper describes a thermal gun built on the principles of High Velocity Air Fuel (HVAF and High Velocity Oxy Fuel (HVOF processes. The designed apparatus can be used for abrasive blasting, coating of surfaces, cutting of rocks, removing rubber from mining equipment, cleaning of contaminations etc.

  3. Anodizing Aluminum with Frills.

    Science.gov (United States)

    Doeltz, Anne E.; And Others

    1983-01-01

    "Anodizing Aluminum" (previously reported in this journal) describes a vivid/relevant laboratory experience for general chemistry students explaining the anodizing of aluminum in sulfuric acid and constrasting it to electroplating. Additions to this procedure and the experiment in which they are used are discussed. Reactions involved are…

  4. Hybrid anode for semiconductor radiation detectors

    Science.gov (United States)

    Yang, Ge; Bolotnikov, Aleksey E; Camarda, Guiseppe; Cui, Yonggang; Hossain, Anwar; Kim, Ki Hyun; James, Ralph B

    2013-11-19

    The present invention relates to a novel hybrid anode configuration for a radiation detector that effectively reduces the edge effect of surface defects on the internal electric field in compound semiconductor detectors by focusing the internal electric field of the detector and redirecting drifting carriers away from the side surfaces of the semiconductor toward the collection electrode(s).

  5. Low temperature anodic bonding to silicon nitride

    DEFF Research Database (Denmark)

    Weichel, Steen; Reus, Roger De; Bouaidat, Salim

    2000-01-01

    Low-temperature anodic bonding to stoichiometric silicon nitride surfaces has been performed in the temperature range from 3508C to 4008C. It is shown that the bonding is improved considerably if the nitride surfaces are either oxidized or exposed to an oxygen plasma prior to the bonding. Both bu...

  6. Progress in Nano-Engineered Anodic Aluminum Oxide Membrane Development

    OpenAIRE

    Gerrard Eddy Jai Poinern; Derek Fawcett; Nurshahidah Ali

    2011-01-01

    The anodization of aluminum is an electro-chemical process that changes the surface chemistry of the metal, via oxidation, to produce an anodic oxide layer. During this process a self organized, highly ordered array of cylindrical shaped pores can be produced with controllable pore diameters, periodicity and density distribution. This enables anodic aluminum oxide (AAO) membranes to be used as templates in a variety of nanotechnology applications without the need for expensive lithographical ...

  7. Using a nitrogen dielectric barrier discharge for surface treatment

    International Nuclear Information System (INIS)

    Borcia, G; Anderson, C A; Brown, N M D

    2005-01-01

    In this paper, continuing previous work, we report on the installation and the testing of an experimental dielectric barrier discharge (DBD) reactor run in a controlled atmospheric pressure gaseous environment other than air. Here, the effects of a N 2 -DBD treatment on the surface of a test polymer material (UHMW polyethylene) are examined, reported, discussed and compared to results obtained previously following air-DBD treatment. Surface analysis and characterization were performed using x-ray photoelectron spectroscopy, contact angle measurement and scanning electron microscopy before and following the DBD processing described. The discharge parameters used were correlated with the changes in the surface characteristics found following DBD treatments of various durations in a nitrogen atmosphere. The work focuses on the control of the gaseous environment supporting the discharge and on the possibility of overcoming the potentially dominant effect of reactive oxygen-related species, derived from any residual air present. The results obtained underline the very high reactivity of such species in the discharge, but are encouraging in respect of the possibility of the implantation or generation of functional groups other than oxygen-related ones at the surface of interest. The processing conditions concerned simulate 'real' continuous high speed processing, allowing the planning of further experiments, where various gaseous mixtures of the type X + N 2 will be used for controlled surface functionalization

  8. Anodizing color coded anodized Ti6Al4V medical devices for increasing bone cell functions.

    Science.gov (United States)

    Ross, Alexandra P; Webster, Thomas J

    2013-01-01

    Current titanium-based implants are often anodized in sulfuric acid (H(2)SO(4)) for color coding purposes. However, a crucial parameter in selecting the material for an orthopedic implant is the degree to which it will integrate into the surrounding bone. Loosening at the bone-implant interface can cause catastrophic failure when motion occurs between the implant and the surrounding bone. Recently, a different anodization process using hydrofluoric acid has been shown to increase bone growth on commercially pure titanium and titanium alloys through the creation of nanotubes. The objective of this study was to compare, for the first time, the influence of anodizing a titanium alloy medical device in sulfuric acid for color coding purposes, as is done in the orthopedic implant industry, followed by anodizing the device in hydrofluoric acid to implement nanotubes. Specifically, Ti6Al4V model implant samples were anodized first with sulfuric acid to create color-coding features, and then with hydrofluoric acid to implement surface features to enhance osteoblast functions. The material surfaces were characterized by visual inspection, scanning electron microscopy, contact angle measurements, and energy dispersive spectroscopy. Human osteoblasts were seeded onto the samples for a series of time points and were measured for adhesion and proliferation. After 1 and 2 weeks, the levels of alkaline phosphatase activity and calcium deposition were measured to assess the long-term differentiation of osteoblasts into the calcium depositing cells. The results showed that anodizing in hydrofluoric acid after anodizing in sulfuric acid partially retains color coding and creates unique surface features to increase osteoblast adhesion, proliferation, alkaline phosphatase activity, and calcium deposition. In this manner, this study provides a viable method to anodize an already color coded, anodized titanium alloy to potentially increase bone growth for numerous implant applications.

  9. Influence of argon plasma treatment on polyethersulphone surface

    Indian Academy of Sciences (India)

    2013-01-09

    Jan 9, 2013 ... waste water treatment from heavy and toxic metals, low-level nuclear waste management and separation of Zr from ... solid surface permits a rapid and qualitative evaluation of the SFE of the polymer. The water contact angle ...

  10. 40 CFR 268.4 - Treatment surface impoundment exemption.

    Science.gov (United States)

    2010-07-01

    ... residues may not be placed in any other surface impoundment for subsequent management. (iv) Recordkeeping... exemption. 268.4 Section 268.4 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID...), the residues from treatment are analyzed, as specified in § 268.7 or § 268.32, to determine if they...

  11. Facile Dry Surface Cleaning of Graphene by UV Treatment

    Science.gov (United States)

    Kim, Jin Hong; Haidari, Mohd Musaib; Choi, Jin Sik; Kim, Hakseong; Yu, Young-Jun; Park, Jonghyurk

    2018-05-01

    Graphene has been considered an ideal material for application in transparent lightweight wearable electronics due to its extraordinary mechanical, optical, and electrical properties originating from its ordered hexagonal carbon atomic lattice in a layer. Precise surface control is critical in maximizing its performance in electronic applications. Graphene grown by chemical vapor deposition is widely used but it produces polymeric residue following wet/chemical transfer process, which strongly affects its intrinsic electrical properties and limits the doping efficiency by adsorption. Here, we introduce a facile dry-cleaning method based on UV irradiation to eliminate the organic residues even after device fabrication. Through surface topography, Raman analysis, and electrical transport measurement characteristics, we confirm that the optimized UV treatment can recover the clean graphene surface and improve graphene-FET performance more effectively than thermal treatment. We propose our UV irradiation method as a systematically controllable and damage-free post process for application in large-area devices.

  12. Surface treatments for material protection in nuclear power plants

    International Nuclear Information System (INIS)

    De, P.K.; Gadiyar, H.S.

    1987-01-01

    The paper highlights some of the surface treatment methods used in nuclear power plants to improve their performance. The corrosion resistance of zirconium alloys results from the formation of an adherent and protective film of ZrO 2 . Graphite coating of zircaloy-2 cladding minimizes the susceptibility to environmental induced cracking. Magnetite formation during the hot conditioning operation improves the corrosion resistance of carbon steel as well as controls the spread of radioactivity. It has been illustrated how the surface treatment is helpful for redistributing residual stress to facilitate conversion of tensile stress to compressive stress to mitigate failures due to stress corrosion and fatigue corrosion. Inhibitors and passivators can modify the surface conditions (in situ) of condenser tubes and cooling water systems. These aspects have been dealt in the text of the paper. (author). 8 refs., 3 figures

  13. Advantages of surface treatment processes by ionic sputtering

    International Nuclear Information System (INIS)

    Gantois, M.

    1976-01-01

    The use of high intensity glow-discharge permits to realize a superficial thermochemical treatment. Ions formed by discharge are accelerated against the surfaces to be treated; by effect of ion bombardment, surfaces get heated and a chemical reaction is developed depending on the composition of the ionized gas. The technique presents advantages, as the potential of the active gas might be freely chosen, and as many gases might be used, the decomposition of gases by pyrolysis and a homogeneous treatment (concerning nature of phases and thickness) all over the surface being not necessary. It is possible to develop layers of various nature, looking for those which offer the best properties to solve a technological problem (wear, friction, fatigue toughness, etc.). Some examples of nitruration, carbonitruration are considered [fr

  14. Effect of Surface Treatment on the Properties of Wool Fabric

    Science.gov (United States)

    Kan, C. W.; Yuen, C. W. M.; Chan, C. K.; Lau, M. P.

    Wool fiber is commonly used in textile industry, however, it has some technical problems which affect the quality and performance of the finished products such as felting shrinkage, handle, lustre, pilling, and dyeability. These problems may be attributed mainly in the presence of wool scales on the fiber surface. Recently, chemical treatments such as oxidation and reduction are the commonly used descaling methods in the industry. However, as a result of the pollution caused by various chemical treatments, physical treatment such as low temperature plasma (LTP) treatment has been introduced recently because it is similarly capable of achieving a comparable descaling effect. Most of the discussions on the applications of LTP treatment on wool fiber were focused on applying this technique for improving the surface wettability and shrink resistance. Meanwhile, little discussion has been made on the mechanical properties, thermal properties, and the air permeability. In this paper, wool fabric was treated with LTP treatment with the use of a non-polymerizing gas, namely oxygen. After the LTP treatment, the fabrics low-stress mechanical properties, air permeability, and thermal properties were evaluated and discussed.

  15. Pre-treatments applied to oxidized aluminum surfaces to modify the interfacial bonding with bis-1,2-(triethoxysilyl)ethane (BTSE)

    International Nuclear Information System (INIS)

    Kim, J.; Teo, M.; Wong, P.C.; Wong, K.C.; Mitchell, K.A.R.

    2005-01-01

    The methods of X-ray photoelectron spectroscopy (XPS), secondary-ion mass spectrometry (SIMS), and scanning electron microscopy (SEM) have been used to investigate aspects of the bonding of bis-1,2-(triethoxysilyl)ethane (BTSE) onto anodized samples of 7075-T6 aluminum alloy that have been subjected to the various pre-treatments considered in Part I. The oxide layer thins when this sample is subjected to a Forest Products Laboratory (FPL) treatment; topographical changes are detected by SEM after only 5 min, and the 'scallop structures' increase in size for longer times of the FPL treatment. These 7075-Al surfaces adsorb more BTSE than the high-purity Al samples considered in Part I, although the interfacial bonding indicated by the [AlOSi] + /[Al 2 O] + SIMS ratios measured for the former samples are constant for different times of FPL treatment, unlike the situation for high-purity Al. Heating anodized 7075-Al samples, either before or after FPL treatment, has no significant effect on the subsequent BTSE adsorption, but a H 2 plasma treatment can enhance the interfacial Al-O-Si bonding with a decrease in the total BTSE polymerization

  16. Pre-treatments applied to oxidized aluminum surfaces to modify the interfacial bonding with bis-1,2-(triethoxysilyl)ethane (BTSE)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J. [Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1 (Canada); Teo, M. [Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1 (Canada); Wong, P.C. [Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1 (Canada); Wong, K.C. [Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1 (Canada); Mitchell, K.A.R. [Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1 (Canada)]. E-mail: karm@chem.ubc.ca

    2005-12-15

    The methods of X-ray photoelectron spectroscopy (XPS), secondary-ion mass spectrometry (SIMS), and scanning electron microscopy (SEM) have been used to investigate aspects of the bonding of bis-1,2-(triethoxysilyl)ethane (BTSE) onto anodized samples of 7075-T6 aluminum alloy that have been subjected to the various pre-treatments considered in Part I. The oxide layer thins when this sample is subjected to a Forest Products Laboratory (FPL) treatment; topographical changes are detected by SEM after only 5 min, and the 'scallop structures' increase in size for longer times of the FPL treatment. These 7075-Al surfaces adsorb more BTSE than the high-purity Al samples considered in Part I, although the interfacial bonding indicated by the [AlOSi]{sup +}/[Al{sub 2}O]{sup +} SIMS ratios measured for the former samples are constant for different times of FPL treatment, unlike the situation for high-purity Al. Heating anodized 7075-Al samples, either before or after FPL treatment, has no significant effect on the subsequent BTSE adsorption, but a H{sub 2} plasma treatment can enhance the interfacial Al-O-Si bonding with a decrease in the total BTSE polymerization.

  17. Surface Treatment of PET Nonwovens with Atmospheric Plasma

    International Nuclear Information System (INIS)

    Li Shufang

    2013-01-01

    In this study, polyethylene-terephthalate (PET) nonwovens are treated using an atmospheric plasma and the effects of the treatment time, treatment power and discharge distance on the ability of water-penetration into the nonwovens are investigated. The result indicates that the method can improve the wettability of PET nonwovens remarkably, but the aging decay of the sample's wettability is found to be notable as a function of the storage time after treatment due to the internal rotation of the single bond of surface macromolecules. As shown by SEM and XPS analysis, the etching and surface reaction are significant, and water-penetration weight is found to increase remarkably with the increasing power. This variation can be attributed to momentum transfer and enhanced higher-energy particle excitation.

  18. A study in the surface treatment of the barrier of a nuclear fuel protector

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yo Seung; Chang, Si Young; Lee, Du Hyung; Noh, Bong Hyun; Kim, Ye Na [Korea Aerospace University, Goyang (Korea, Republic of)

    2009-06-15

    Materials used in the nuclear power plant, such as pipe, are needed to endure severe corrosion because they could expose the high temperature coolant under radiation. Up to now, the HT9 steel(12Cr-1MoVW) which is one of Ferritic Martensite Stainless steels has been applied because of its high swelling resistance. However, its applications are limited to the temperature of approximately 500 .deg. C. Therefore, it has been strongly demanded that the materials have excellent corrosion resistance concurrent with high mechanical properties such as fracture toughness and irradiation resistance at higher temperatures of more than 500 .dec. C for high efficiency of operating reactor. In order to overcome the corrosion problem of irradiated HT9 steel causing severe environmental problem, particularly, the ceramic coating methods could be applied. Recently, plasma electrolytic oxidation (PEO) emerged as a novel technique being capable of thick, dense and hard oxide ceramic coatings on the surface of light materials. In this study, we focused on applying the newly developed coating method, Plasma Electrolytic Oxidation (PEO) which was mainly developed for non-ferrous materials such as Al, Mg and Ti, for the HT9 steel. And then, we investigated and evaluated the possibility of application of PEO method for HT9 steel treated with/without aluminum cladding based on the microstructure observation of coatings formed under various processing parameters such as current ratio, electrolyte and time. Plasma Electrolytic Oxidation (PEO) treatment, which is an advancement of the conventional electrochemical anodizing treatment and leads to the local formation of a plasma by a spark on the metal surface, is expected to be a promising surface treatment that can overcome the drawbacks of HT9 steel. We applied PEO treatment for HT9 steel. We tried to find the effect of processing parameters, such as coating time, current ratio and electrolyte, on PEO coatings of HT9 steel, and also studied

  19. Effects of Surface Treatment of Activated Carbon on Its Surface and Cr(VI) Adsorption Characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Park, Soo Jin; Jang, Yu Sin [Advanced Materials Division., Korea Research Institute of Chimical Technology, Taejon (Korea)

    2001-04-01

    In this work, the effect of surface treatments on activated carbons (ACs) has been studied in the context of gas and liquid adsorption behaviors. The chemical solutions used in this experiment were 35% sodium hydroxide, and these were used for the acidic and basic treatments, respectively. The surface properties have been determined by pH, acid-base values, and FT-IR. The adsorption isotherms of Cr(VI) ion on activated carbons have been studied with the 5 mg/l concentration at ambient temperature. N{sub 2} adsorption isotherm characteristics, which include the specific surface area, micro pore volume, and microporosity, were determined by BET and Boer's-plot methods. In case of the acidic treatment of activated carbons, it was observed that the adsorption of Cr(VI) ion was more effective due to the increase acid value (or acidic functional group) of activated carbon surfaces. However, the basic treatment on activated carbons was caused no significant effects, probably due to the decreased specific surface area and total pore volume. 27 refs., 7 figs., 4 tabs.

  20. Comprehensive surface treatment of high-speed steel tool

    Science.gov (United States)

    Fedorov, Sergey V.; Aleshin, Sergey V.; Swe, Min Htet; Abdirova, Raushan D.; Kapitanov, Alexey V.; Egorov, Sergey B.

    2018-03-01

    One of the promising directions of hardening of high-speed steel tool is the creation on their surface of the layered structures with the gradient of physic-chemical properties between the wear-resistant coatings to the base material. Among the methods of such surface modification, a special process takes place based on the use of pulsed high-intensity charged particle beams. The high speed of heating and cooling allows structural-phase transformations in the surface layer, which cannot be realized in a stationary mode. The treatment was conducted in a RITM-SP unit, which constitutes a combination of a source of low-energy high-current electron beams "RITM" and two magnetron spraying systems on a single vacuum chamber. The unit enables deposition of films on the surface of the desired product and subsequent liquid-phase mixing of materials of the film and the substrate by an intense pulse electron beam. The article discusses features of the structure of the subsurface layer of high-speed steel M2, modified by surface alloying of a low-energy high-current electron beam, and its effect on the wear resistance of the tool when dry cutting hard to machine Nickel alloy. A significant decrease of intensity of wear of high-speed steel with combined treatment happens due to the displacement of the zone of wear and decrease the radius of rounding of the cutting edge because of changes in conditions of interaction with the material being treated.

  1. Surface treatments of metal supports for photocatalysis applications

    Energy Technology Data Exchange (ETDEWEB)

    Montecchio, Francesco, E-mail: fmon@kth.se [KTH, Royal Institute of Technology, Dept. of Chemical Engineering and Technology, 100 44 Stockholm (Sweden); Chinungi, Don [KTH, Royal Institute of Technology, Dept. of Chemical Engineering and Technology, 100 44 Stockholm (Sweden); Lanza, Roberto [Verdant Chemical Technologies AB, 114 28 Stockholm (Sweden); Engvall, Klas [KTH, Royal Institute of Technology, Dept. of Chemical Engineering and Technology, 100 44 Stockholm (Sweden)

    2017-04-15

    Highlights: • Treated metals can be used as photocatalyst support in full-scale applications. • Various electrochemical treatments were performed, checking the surface corrugation. • Stainless steel etched in DC and aqua regia shows the highest surface modification. • P25 coated on the DC etched sample has a high stability, with constant activity. • The support modification increases the UV irradiated area and the activity of P25. - Abstract: One of the most important challenges, for scaling up a photocatalytic system for VOCs abatement to full-scale, is the design of a suitable photocatalyst support. The support has to firmly immobilize the photocatalyst, without using an organic adhesive, and should also withstand relatively high mechanical stresses. Metals may be effectively implemented as a support material, after a corrugation of the surface with electrochemical treatments. In the present work, we treated stainless steel and aluminum supports, evaluating the surface modifications due to the electrochemical treatments, with scanning electron microscopy (SEM) and confocal microscopy. Five samples showing the highest degree of restructuring were selected and spray coated with P25, a TiO{sub 2} photocatalyst, evaluating the mechanical stability of the coating with a standard tape test method. One particular stainless steel sample presented a superior surface restructuring and coating stability. The photocatalytic activity of this sample, evaluated measuring the complete oxidation of acetaldehyde, was tested for 15 h, and compared with sample of TiO{sub 2}-P25 on a ceramic support. The stainless steel exhibited a constant performance after an initial stabilization period. The stainless steel sample showed a slightly higher activity, due to the surface restructuring, increasing the irradiated area available for the coated photocatalyst.

  2. X-ray tube rotating anode

    International Nuclear Information System (INIS)

    Friedel, R.

    1979-01-01

    The anode disk of the X-ray rotating anode is blackened on the surface outside the focal spot tracks in order to improve the heat radiation. In particular the side opposite the focal spot tracks is provided with many small holes, the ratio of depth to cross-section ('pit ratio') being as large as possible: ranging from 2:1 to 10:1. They are arranged so densely that the radiating surface will nearly have the effect of a black body. (RW) [de

  3. Transfer matrix treatment of atomic chemisorption on transition metal surface

    International Nuclear Information System (INIS)

    Mariz, A.M.; Koiller, B.

    1980-05-01

    The atomic adsorption of hydrogen on paramagnetic nickel 100 surface is studied, using the Green's function formalism and the transfer matrix technique, which allows the treatment of the geometry of the system in a simple manner. Electronic correlation at the adatom orbital in a self consistent Hartree-Fock approach is incorporated. The adsorption energy, local density of states and charge transfer between the solid and the adatom are calculated for different crystal structures (sc and fcc) and adatom positions at the surface. The results are discussed in comparison with other theories and with available experimental data, with satisfactory agreement. (Author) [pt

  4. Electrochemical performance of Sn-Sb-Cu film anodes prepared by layer-by-layer electrodeposition

    International Nuclear Information System (INIS)

    Jiang Qianlei; Xue Ruisheng; Jia Mengqiu

    2012-01-01

    A novel layer-by-layer electrodeposition and heat-treatment approach was attempted to obtain Sn-Sb-Cu film anode for lithium ion batteries. The preparation of Sn-Sb-Cu anodes started with galvanostatic electrochemically depositing antimony and tin sequentially on the substrate of copper foil collector. Sn-Sb and Cu-Sb alloys were formed when heated. The SEM analysis showed that the crystalline grains become bigger and the surface of the Sn-Sb-Cu anode becomes more denser after annealing. The energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analysis showed the antimony, tin and copper were alloyed to form SnSb and Cu 2 Sb after heat treatment. The X-ray photoelectron spectroscopy (XPS) analysis showed the surface of the Sn-Sb-Cu electrode was covered by a thin oxide layer. Electrochemical measurements showed that the annealed Sn-Sb-Cu anode has high reversible capacity and good capacity retention. It exhibited a reversible capacity of about 962 mAh/g in the initial cycle, which still remained 715 mAh/g after 30 cycles.

  5. Patterned titania nanostructures produced by electrochemical anodization of titanium sheet

    Science.gov (United States)

    Dong, Junzhe; Ariyanti, Dessy; Gao, Wei; Niu, Zhenjiang; Weil, Emeline

    2017-07-01

    A two-step anodization method has been used to produce patterned arrays of TiO2 on the surface of Ti sheet. Hexagonal ripples were created on Ti substrate after removing the TiO2 layer produced by first-step anodization. The shallow concaves were served as an ideal position for the subsequent step anodization due to their low electrical resistance, resulting in novel hierarchical nanostructures with small pits inside the original ripples. The mechanism of morphology evolution during patterned anodization was studied through changing the anodizing voltages and duration time. This work provides a new idea for controlling nanostructures and thus tailoring the photocatalytic property and wettability of anodic TiO2.

  6. Structural comparison of anodic nanoporous-titania fabricated from single-step and three-step of anodization using two paralleled-electrodes anodizing cell

    Directory of Open Access Journals (Sweden)

    Mallika Thabuot

    2016-02-01

    Full Text Available Anodization of Ti sheet in the ethylene glycol electrolyte containing 0.38wt% NH4F with the addition of 1.79wt% H2O at room temperature was studied. Applied potential of 10-60 V and anodizing time of 1-3 h were conducted by single-step and three-step of anodization within the two paralleled-electrodes anodizing cell. Their structural and textural properties were investigated by X-ray diffraction (XRD and scanning electron microscopy (SEM. After annealing at 600°C in the air furnace for 3 h, TiO2-nanotubes was transformed to the higher proportion of anatase crystal phase. Also crystallization of anatase phase was enhanced as the duration of anodization as the final step increased. By using single-step of anodization, pore texture of oxide film was started to reveal at the applied potential of 30 V. Better orderly arrangement of the TiO2-nanotubes array with larger pore size was obtained with the increase of applied potential. The applied potential of 60 V was selected for the three-step of anodization with anodizing time of 1-3 h. Results showed that the well-smooth surface coverage with higher density of porous-TiO2 was achieved using prolonging time at the first and second step, however, discontinuity tube in length was produced instead of the long-vertical tube. Layer thickness of anodic oxide film depended on the anodizing time at the last step of anodization. More well arrangement of nanostructured-TiO2 was produced using three-step of anodization under 60 V with 3 h for each step.

  7. Electrically conductive anodized aluminum coatings

    Science.gov (United States)

    Alwitt, Robert S. (Inventor); Liu, Yanming (Inventor)

    2001-01-01

    A process for producing anodized aluminum with enhanced electrical conductivity, comprising anodic oxidation of aluminum alloy substrate, electrolytic deposition of a small amount of metal into the pores of the anodized aluminum, and electrolytic anodic deposition of an electrically conductive oxide, including manganese dioxide, into the pores containing the metal deposit; and the product produced by the process.

  8. Chromium surface alloying of structural steels during laser treatment

    International Nuclear Information System (INIS)

    Kurov, I.E.; Nagornykh, S.N.; Sivukhin, G.A.; Solenov, S.V.

    1987-01-01

    Results of matrix alloying from the surface layer and creation of considerably increased chromium concentration in the depth which permits to increase the efficiency of laser treatment of steels (12Kh18N10T and 38KhN3M) in the process of their further mechanical polishing, are presented. The treatment was realized by continuous CO 2 -laser at different power densities and scanning rates are presented. A model describing the creation of anomalous distributions of the alloying element in steels is plotted

  9. Hybrid fuzzy logic control of laser surface heat treatments

    International Nuclear Information System (INIS)

    Perez, Jose Antonio; Ocana, Jose Luis; Molpeceres, Carlos

    2007-01-01

    This paper presents an advanced hybrid fuzzy logic control system for laser surface heat treatments, which allows to increase significantly the uniformity and final quality of the obtained product, reducing the rejection rate and increasing the productivity and efficiency of the treatment. Basically, the proposed hybrid control structure combines a fuzzy logic controller, with a pure integral action, both fully decoupled, improving the performances of the process with a reasonable design cost, since the system nonlinearities are fully compensated by the fuzzy component of the controller, while the integral action contributes to eliminate the steady-state error

  10. Growth of anodic films on compound semiconductor electrodes: InP in aqueous (NH sub 4) sub 2 S

    CERN Document Server

    Buckley, D N

    2002-01-01

    Film formation on compound semiconductors under anodic conditions is discussed. The surface properties of InP electrodes were examined following anodization in a (NH sub 4) sub 2 S electrolyte. The observation of a current peak in the cyclic voltammetric curve was attributed to selective etching of the substrate and a film formation process. AFM images of samples anodized in the sulfide solution revealed surface pitting. Thicker films formed at higher potentials exhibited extensive cracking as observed by optical and electron microscopy, and this was explicitly demonstrated to occur ex situ rather than during the electrochemical treatment. The composition of the thick film was identified as In sub 2 S sub 3 by EDX and XPS. The measured film thickness varies linearly with the charge passed, and comparison between experimental thickness measurements and theoretical estimates for the thickness indicate a porosity of over 70 %. Cracking is attributed to shrinkage during drying of the highly porous film and does n...

  11. Coating for lithium anode, thionyl chloride active cathode electrochemical cell

    Energy Technology Data Exchange (ETDEWEB)

    Catanzarite, V.O.

    1983-01-04

    Electrochemical power cells having a cathode current collector, a combination liquid active cathode depolarizer electrolyte solvent and an anode that forms surface compounds when in intimate contact with the liquid cathode are enhanced by the addition of a passivation limiting film contiguous to said anode. The passivating film is a member of the cyanoacrilate family of organic compounds.

  12. Coating for lithium anode, thionyl chloride active cathode electrochemical cell

    Energy Technology Data Exchange (ETDEWEB)

    Catanzarite, V.O.

    1981-10-20

    Electrochemical power cells having a cathode current collector, a combination liquid active cathode depolarizer electrolyte solvent and an anode that forms surface compounds when in intimate contact with the liquid cathode are enhanced by the addition of a passivation limiting film contiguous to said anode. The passivating film is a member of the cyanoacrilate family of organic compounds.

  13. Effect of different surface treatments on bond strength, surface and microscopic structure of zirconia ceramic

    Directory of Open Access Journals (Sweden)

    Zeinab R. El-Shrkawy

    2016-06-01

    Conclusions: (1 Surface treatments of Y-TZP ceramic together with MDP primer and silane-coupling agent application improve the bond strength to resin cement. (2 Plasma-Silica coating and plasma-oxygen treatment, both are valuable methods that improve the bond strength of resin cement to Y-TZP ceramic. (3 Silica coating by plasma technology provides durable bond strength and can be a promising alternative pretreatment before silane application to enhance bonding with zirconia ceramic. (4 Tetragonal-monoclinic phase transformation had occurred in Y-TZP samples received both types of plasma treatment.

  14. Electrochemically exfoliated graphene anodes with enhanced biocurrent production in single-chamber air-breathing microbial fuel cells.

    Science.gov (United States)

    Najafabadi, Amin Taheri; Ng, Norvin; Gyenge, Előd

    2016-07-15

    Microbial fuel cells (MFCs) present promising options for environmentally sustainable power generation especially in conjunction with waste water treatment. However, major challenges remain including low power density, difficult scale-up, and durability of the cell components. This study reports enhanced biocurrent production in a membrane-free MFC, using graphene microsheets (GNs) as anode and MnOx catalyzed air cathode. The GNs are produced by ionic liquid assisted simultaneous anodic and cathodic electrochemical exfoliation of iso-molded graphite electrodes. The GNs produced by anodic exfoliation increase the MFC peak power density by over 300% compared to plain carbon cloth (i.e., 2.85Wm(-2) vs 0.66Wm(-2), respectively), and by 90% compared to conventional carbon black (i.e., Vulcan XC-72) anode. These results exceed previously reported power densities for graphene-containing MFC anodes. The fuel cell polarization results are corroborated by electrochemical impedance spectroscopy indicating three times lower charge transfer resistance for the GN anode. Material characterizations suggest that the best performing GN samples were of relatively smaller size (~500nm), with higher levels of ionic liquid induced surface functionalization during the electrochemical exfoliation process. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Graphoepitaxy of sexithiophene and orientation control by surface treatment

    International Nuclear Information System (INIS)

    Ikeda, Susumu; Saiki, Koichiro; Wada, Yasuo; Inaba, Katsuhiko; Ito, Yoshiyasu; Kikuchi, Hirokazu; Terashima, Kazuo; Shimada, Toshihiro

    2008-01-01

    The factors influencing the graphoepitaxy of organic semiconductor α-sexithiophene (6T) on thermally oxidized silicon substrates were studied and it was discovered that a wider pitch in the microgrooves decreased the degree of graphoepitaxy. A more significant finding was that in-plane orientation could be changed by simple surface treatment. On UV/ozone-treated substrates (hydrophilic condition), the b-axis of 6T was parallel to the grooves. Further surface treatment with hexamethyl-disiloxane (under hydrophobic conditions) changed this in-plane orientation by 90 deg. This change is due to the interaction between the topmost chemical species (functional groups) of the groove walls and organic molecules, a behavior peculiar to organic graphoepitaxy and exploitable for optimal orientation control in device processing. The nucleation and growth processes that cause the graphoepitaxy are discussed, based on the experimental results

  16. Growth behavior of anodic porous alumina formed in malic acid solution

    Science.gov (United States)

    Kikuchi, Tatsuya; Yamamoto, Tsuyoshi; Suzuki, Ryosuke O.

    2013-11-01

    The growth behavior of anodic porous alumina formed on aluminum by anodizing in malic acid solutions was investigated. High-purity aluminum plates were electropolished in CH3COOH/HClO4 solutions and then anodized in 0.5 M malic acid solutions at 293 K and constant cell voltages of 200-350 V. The anodic porous alumina grew on the aluminum substrate at voltages of 200-250 V, and a black, burned oxide film was formed at higher voltages. The nanopores of the anodic oxide were only formed at grain boundaries of the aluminum substrate during the initial stage of anodizing, and then the growth region extended to the entire aluminum surface as the anodizing time increased. The anodic porous alumina with several defects was formed by anodizing in malic acid solution at 250 V, and oxide cells were approximately 300-800 nm in diameter.

  17. Surface treatments for biological, chemical and physical applications

    CERN Document Server

    Karaman, Mustafa

    2017-01-01

    A step-by-step guide to the topic with a mix of theory and practice in the fields of biology, chemistry and physics. Straightforward and well-structured, the first chapter introduces fundamental aspects of surface treatments, after which examples from nature are given. Subsequent chapters discuss various methods to surface modification, including chemical and physical approaches, followed by the characterization of the functionalized surfaces. Applications discussed include the lotus effect, diffusion barriers, enzyme immobilization and catalysis. Finally, the book concludes with a look at future technology advances. Throughout the text, tutorials and case studies are used for training purposes to grant a deeper understanding of the topic, resulting in an essential reference for students as well as for experienced engineers in R&D.

  18. The aluminum anode in deep ocean environments

    International Nuclear Information System (INIS)

    Schreiber, C.F.

    1989-01-01

    Results of field and mini-plant studies are presented for A1 + 0.045% Hg + 0.1% Si + 0.45% Zn* and A1 + 0.015% In + 0.1% Si + 3% Zn** anodes in varying depths of natural seawater. Current capacity and potential information are presented. In addition to information on anode current capacity and potential, polarization curves were obtained on both aluminum alloys using potentiostatic techniques at a simulated ocean depth of 1090 ft. (332 m). These data were compared with similarly run experiments at ocean surface pressures. As a basis of comparison, zinc anodes (U.S. Mil-A-18001H) were included as a companion alloy. Information gained on zinc is sufficient to accurately represent the behavior of this alloy. Results conclude that conditions of high pressure (and low temperature) associated with the alloys under test did not alter their galvanic behavior from that noted at the ocean surface

  19. Effect of alkali treatment on surface morphology of titanium

    Energy Technology Data Exchange (ETDEWEB)

    Tan, K. J., E-mail: gd130056@siswa.uthm.edu.my; Wahab, M. A. A., E-mail: cd110006@siswa.uthm.edu.my; Mahmod, S., E-mail: cd110201@siswa.uthm.edu.my; Idris, M. I., E-mail: izwana@uthm.edu.my; Abdullah, H. Z., E-mail: hasan@uthm.edu.my [Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, Batu Pahat, Johor (Malaysia)

    2015-07-22

    Alkali and heat treatments were first introduced by Kim et al. to prepare a bioactive surface on titanium. This method has been proven very effective and widely used in other studies to promote titanium osteointegration. This study aims to investigate further the effect of alkali treatment on surface morphology of high purity titanium. High purity titanium foils were immersed in NaOH aqueous solutions of 0.5 M, 5 M and 15 M at 60°C and 80 °C for 1, 3 and 7 days. The surface morphology was examined using Field Emission Scanning Electron Microscope (FESEM). The obtained phases were analysed using Fourier Transform Infrared Spectroscopy (FTIR) in the spectra range of 4000-600 cm{sup −1} at 4 cm{sup −1} resolution and 50 scans. At the same soaking temperature and soaking time, a thicker porous network was observed with increasing concentration of NaOH. At the same soaking temperature, a much porous structure was observed with increasing soaking time. At constant alkali concentration, more homogenously distributed porous surface structure was observed with increasing soaking temperature.

  20. Passivation of mechanically polished, chemically etched and anodized zirconium in various aqueous solutions: Impedance measurements

    International Nuclear Information System (INIS)

    Abo-Elenien, G.M.; Abdel-Salam, O.E.

    1987-01-01

    Zirconium and its alloys are finding increasing applications especially in water-cooled nuclear reactors. Because of the fact that zirconium is electronegative (E 0 = -1.529V) its corrosion resistance in aqueous solutions is largely determined by the existence of a thin oxide film on its surface. The structure and properties of this film depend in the first place on the method of surface pre-treatment. This paper presents an experimental study of the nature of the oxide film on mechanically polished, chemically etched and anodized zirconium. Ac impedance measurements carried out in various acidic, neutral and alkaline solutions show that the film thickness depends on the method of surface pre-treatment and the type of electrolyte solution. The variation of the potential and impedance during anodization of zirconium at low current density indicates that the initial stages of polarization consist of oxide build-up at a rate dependent on the nature of the electrode surface and the electrolyte. Oxygen evolution commences at a stage where oxide thickening starts to decline. The effect of frequency on the measured impedance indicates that the surface reactivity, and hence the corrosion rate, decreases in the following order: mechanically polished > chemically etched > anodized

  1. Anode Support Creep

    DEFF Research Database (Denmark)

    2015-01-01

    Initial reduction temperature of an SOC is kept higher than the highest intended operation temperature of the SOC to keep the electrolyte under compression by the Anode Support at all temperatures equal to and below the maximum intended operation temperature....

  2. Work function modifications of graphite surface via oxygen plasma treatment

    Science.gov (United States)

    Duch, J.; Kubisiak, P.; Adolfsson, K. H.; Hakkarainen, M.; Golda-Cepa, M.; Kotarba, A.

    2017-10-01

    The surface modification of graphite by oxygen plasma was investigated experimentally (X-ray diffraction, nanoparticle tracking analysis, laser desorption ionization mass spectrometry, thermogravimetry, water contact angle) and by molecular modelling (Density Functional Theory). Generation of surface functional groups (mainly sbnd OHsurf) leads to substantial changes in electrodonor properties and wettability gauged by work function and water contact angle, respectively. The invoked modifications were analyzed in terms of Helmholtz model taking into account the theoretically determined surface dipole moment of graphite-OHsurf system (μ = 2.71 D) and experimentally measured work function increase (from 0.75 to 1.02 eV) to determine the sbnd OH surface coverage (from 0.70 to 1.03 × 1014 groups cm-2). Since the plasma treatment was confined to the surface, the high thermal stability of the graphite material was preserved as revealed by the thermogravimetric analysis. The obtained results provide a suitable quantitative background for tuning the key operating parameters of carbon electrodes: electronic properties, interaction with water and thermal stability.

  3. Anodic oxidation of benzoquinone using diamond anode.

    Science.gov (United States)

    Panizza, Marco

    2014-01-01

    The anodic degradation of 1,4-benzoquinone (BQ), one of the most toxic xenobiotic, was investigated by electrochemical oxidation at boron-doped diamond anode. The electrolyses have been performed in a single-compartment flow cell in galvanostatic conditions. The influence of applied current (0.5-2 A), BQ concentration (1-2 g dm(-3)), temperature (20-45 °C) and flow rate (100-300 dm(3) h(-1)) has been studied. BQ decay kinetic, the evolution of its oxidation intermediates and the mineralization of the aqueous solutions were monitored during the electrolysis by high-performance liquid chromatograph (HPLC) and chemical oxygen demand (COD) measurements. The results obtained show that the use of diamond anode leads to total mineralization of BQ in any experimental conditions due to the production of oxidant hydroxyl radicals electrogenerated from water discharge. The decay kinetics of BQ removal follows a pseudo-first-order reaction, and the rate constant increases with rising current density. The COD removal rate was favoured by increasing of applied current, recirculating flow rate and it is almost unaffected by solution temperature.

  4. Alkylation of gold surface by treatment with C18H37HgOTs and anodic Hg stripping

    Czech Academy of Sciences Publication Activity Database

    Mucha, Malgorzata; Kaletová, Eva; Kohutová, Anna; Scholz, F.; Stensrud, Elizabeth; Stibor, Ivan; Pospíšil, Lubomír; Wrochem von, F.; Michl, Josef

    2013-01-01

    Roč. 135, č. 15 (2013), s. 5669-5677 ISSN 0002-7863 R&D Projects: GA ČR GA203/07/1619; GA ČR GA203/09/0705 EU Projects: European Commission(XE) 213382 - FUNMOL; European Commission(XE) 227756 - DIPOLAR ROTOR ARRAY Institutional support: RVO:61388963 ; RVO:61388955 Keywords : self-assembled monolayers * altitudinal molecular rotors * AU(111) * mercury Subject RIV: CC - Organic Chemistry Impact factor: 11.444, year: 2013

  5. Highly reversible and fast sodium storage boosted by improved interfacial and surface charge transfer derived from the synergistic effect of heterostructures and pseudocapacitance in SnO2-based anodes.

    Science.gov (United States)

    Li, Xin; Sun, Xiaohong; Gao, Zhiwen; Hu, Xudong; Ling, Rui; Cai, Shu; Zheng, Chunming; Hu, Wenbin

    2018-02-01

    Sodium-ion batteries have attracted worldwide attention as potential alternatives for large scale stationary energy storage due to the rich reserves and low cost of sodium resources. However, the practical application of sodium-ion batteries is restricted by unsatisfying capacity and poor rate capability. Herein, a novel mechanism of improving both interfacial and surface charge transfer is proposed by fabricating a graphene oxide/SnO 2 /Co 3 O 4 nanocomposite through a simple hydrothermal method. The formation of heterostructures between ultrafine SnO 2 and Co 3 O 4 could enhance the charge transfer of interfaces owing to the internal electric field. The pseudocapacitive effect, which is led by the high specific area and the existence of ultrafine nanoparticles, takes on a feature of fast faradaic surface charge-transfer. Benefiting from the synergistic advantages of the heterostructures and the pseudocapacitive effect, the as-prepared graphene oxide/SnO 2 /Co 3 O 4 anode achieved a high reversible capacity of 461 mA h g -1 after 80 cycles at a current density of 0.1 A g -1 . Additionally, at a high current density of 1 A g -1 , a high reversible capacity of 241 mA h g -1 after 500 cycles is obtained. A full cell coupled by the as-prepared graphene oxide/SnO 2 /Co 3 O 4 anode and the Na 3 V 2 (PO 4 ) 3 cathode was also constructed, which exhibited a reversible capacity of 310.3 mA h g -1 after 100 cycles at a current density of 1 A g -1 . This method of improving both interfacial and surface charge transfer may pave the way for the development of high performance sodium-ion batteries.

  6. La modified TiO{sub 2} photoanode and its effect on DSSC performance: A comparative study of doping and surface treatment on deep and surface charge trapping

    Energy Technology Data Exchange (ETDEWEB)

    Ako, Rajour Tanyi [Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, BE1410, Negara Brunei Darussalam (Brunei Darussalam); Ekanayake, Piyasiri, E-mail: piyasiri.ekanayake@ubd.edu.bn [Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, BE1410, Negara Brunei Darussalam (Brunei Darussalam); Centre for Advanced Material and Energy Sciences (CAMES), Universiti Brunei Darussalam, Jalan Tungku Link, BE1410, Negara Brunei Darussalam (Brunei Darussalam); Tan, Ai Ling [Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, BE1410, Negara Brunei Darussalam (Brunei Darussalam); Young, David James [Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, BE1410, Negara Brunei Darussalam (Brunei Darussalam); Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, Queensland, 4558 (Australia); Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research - A*STAR, #08-03, 2 Fusionopolis Way, Innovis, 138634 (Singapore)

    2016-04-01

    The effect of Lanthanum ions (La{sup 3+}) on charge trapping in dye-sensitized solar cell (DSSC) photoanodes has been investigated with doped and surface-treated TiO{sub 2} nanoparticles. Doped nanoparticles consisting of 0.5 mol.% Mg and La co-doped TiO{sub 2}, 0.5 mol.% Mg doped TiO{sub 2} and pure TiO{sub 2} were synthesized by the sol gel method. Surface-treated nanoparticles of Mg doped TiO{sub 2} and pure TiO{sub 2} were prepared by ball milling in 0.05 M aqueous La{sup 3+} solution. All materials were analyzed by XRD, XPS and UV–Vis DRS. Cell performance, surface free energy state changes and electron injection efficiency of DSSCs based on these nanoparticles were evaluated using current –voltage measurements, EIS and Incident photon to current conversion efficiency. Doped materials had La and Mg ions incorporated into the TiO{sub 2} lattice, while no lattice changes were observed for the surface-treated materials. Less visible light was absorbed by treated oxides compared with doped oxide samples. The overall power conversion efficiencies (PCE) of DSSC photoanodes based on doped materials were twice those of photoanodes fabricated from treated nanoparticles. Doping establishes deep traps that reduce the recombination of electron–hole (e–h) pairs. Conversely, the presence of absorbed oxygen in treated materials enhances e–h recombination with electrolyte at surface trap sites. - Highlights: • DSSC performance is investigated using photoanodes of doped and La{sup 3+} surface treated TiO{sub 2}. • TiO{sub 2} and Mg–TiO{sub 2} treated with La{sup 3+} absorbed less visible light. • A high concentration of absorbed oxygen on surface treated oxides reduced band bending. • Increased surface free energy in the modified DSSC anodes is caused more by Mg{sup 2+} at Ti{sup 4+} than by La{sup 3+} at the surfaces. • Near surface charge traps due to La{sup 3+} treatment promotes e–h recombination.

  7. Linear sweep anodic stripping voltammetry: Determination of ...

    Indian Academy of Sciences (India)

    The aim of this work is to determine Cr(VI) in water resources by anodic stripping voltammetry using SPE-. AuNPs modified electrode .... surface area about 4 fold). 3.2 Optimization of Parameters ..... in water samples. The above system offers a.

  8. Anode materials for lithium-ion batteries

    Science.gov (United States)

    Sunkara, Mahendra Kumar; Meduri, Praveen; Sumanasekera, Gamini

    2014-12-30

    An anode material for lithium-ion batteries is provided that comprises an elongated core structure capable of forming an alloy with lithium; and a plurality of nanostructures placed on a surface of the core structure, with each nanostructure being capable of forming an alloy with lithium and spaced at a predetermined distance from adjacent nanostructures.

  9. Laser Surface Treatment and Modification of Aluminum Alloy Matrix Composites

    Science.gov (United States)

    Abbass, Muna Khethier

    2018-02-01

    The present work aimed to study the laser surface treatment and modification of Al-4.0%Cu-1.0%Mg alloy matrix composite reinforced with 10%SiC particles produced by stir casting. The specimens of the base alloy and composite were irradiated with an Nd:YAG laser of 1000 mJ, 1064 nm and 3 Hz . Dry wear test using the pin-on -disc technique at different sliding times (5-30 min) at a constant applied load and sliding speed were performed before and after laser treatment. Micro hardness and wear resistance were increased for all samples after laser hardening treatment. The improvement of these properties is explained by microstructural homogenization and grain refinement of the laser treated surface. Modification and refinement of SiC particles and grain refinement in the microstructure of the aluminum alloy matrix (α-Al) were observed by optical and SEM micrographs. The highest increase in hardness was 21.4% and 26.2% for the base alloy and composite sample respectively.

  10. SEM Analysis of Surface Impact on Biofilm Antibiotic Treatment.

    Science.gov (United States)

    Gomes, Luciana Calheiros; Mergulhão, Filipe José

    2017-01-01

    The aim of this work was to use scanning electron microscopy (SEM) to investigate the effect of ampicillin treatment on Escherichia coli biofilms formed on two surface materials with different properties, silicone (SIL) and glass (GLA). Epifluorescence microscopy (EM) was initially used to assess biofilm formation and killing efficiency on both surfaces. This technique showed that higher bacterial colonization was obtained in the hydrophobic SIL than in the hydrophilic GLA. It has also shown that higher biofilm inactivation was attained for GLA after the antibiotic treatment (7-log reduction versus 1-log reduction for SIL). Due to its high resolution and magnification, SEM enabled a more detailed analysis of the antibiotic effect on biofilm cells, complementing the killing efficiency information obtained by EM. SEM micrographs revealed that ampicillin-treated cells have an elongated form when compared to untreated cells. Additionally, it has shown that different materials induced different levels of elongation on cells exposed to antibiotic. Biofilms formed on GLA showed a 37% higher elongation than those formed on SIL. Importantly, cell elongation was related to viability since ampicillin had a higher bactericidal effect on GLA-formed biofilms. These findings raise the possibility of using SEM for understanding the efficacy of antimicrobial treatments by observation of biofilm morphology.

  11. RF atmospheric plasma jet surface treatment of paper

    Science.gov (United States)

    Pawlat, Joanna; Terebun, Piotr; Kwiatkowski, Michał; Diatczyk, Jaroslaw

    2016-09-01

    A radio frequency RF atmospheric pressure plasma jet was used to enhance the wettability of cellulose-based paper of 90 g m-2 and 160 g m-2 grammage as a perspective platform for antibiotic sensitivity tests. Helium and argon were the carrier gases for oxygen and nitrogen; pure water and rapeseed oil were used for goniometric tests. The influence of the flow rate and gas type, the power of the discharge, and distance from the nozzle was examined. The surface structure was observed using an optical microscope. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectra were investigated in order to determine whether cellulose degradation processes occurred. The RF plasma jet allowed us to decrease the surface contact angle without drastic changes in other features of the tested material. Experiments confirmed the significant influence of the distance between the treated sample and reactor nozzle, especially for treatment times longer than 15 s due to the greater concentration of reactive species at the surface of the sample, which decreases with distance—and their accumulation effect with time. The increase of discharge power plays an important role in decreasing the surface contact angle for times longer than 10 s. Higher power had a positive effect on the amount of generated active particles and facilitated the ignition of discharge. However, a too high value can cause a rise in temperature of the material and heat-caused damage.

  12. Alternative to chrome in the aluminium surface finishing industry. Low environmental impact surface treatments

    International Nuclear Information System (INIS)

    Aballe Villero, A.; Bethencourt Nunez, M.; Botana Pedemonte, F. J.; Marco Barcena, M.; Sanchez-Amaya, J. M.

    2001-01-01

    Chromates are one of the most commonly used compounds in anti corrosive protection systems because of its excellent rate efficiency/cost. In the case of aluminium alloys, these compounds are employed as inhibitors as well as in the anti-corrosive pretreatments to develop protective films. However, chromates are highly toxic and its use involves a high risk for health and environment. Consequently, in the last years intensive efforts have been achieved in the surface treatment industry to find ecological alternatives to this kind of compounds. In this work, the main alternatives proposed in literature to substitute chromates in the surface treatments of aluminium alloys are reviewed. To begin with, the role of chromates in these systems and their environmental consequences has been briefly reviewed. (Author) 16 refs

  13. A new, high energy rechargeable lithium ion battery with a surface-treated Li{sub 1.2}Mn{sub 0.54}Ni{sub 0.13}Co{sub 0.13}O{sub 2} cathode and a nano-structured Li{sub 4}Ti{sub 5}O{sub 12} anode

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaoyu; Huang, Tao; Yu, Aishui, E-mail: asyu@fudan.edu.cn

    2015-11-05

    Through elaborate design, a new rechargeable lithium ion battery has been developed by comprising a surface-treated Li{sub 1.2}Mn{sub 0.54}Ni{sub 0.13}Co{sub 0.13}O{sub 2} cathode and a nano-structured Li{sub 4}Ti{sub 5}O{sub 12} anode. After precondition Na{sub 2}S{sub 2}O{sub 8} treatment, the initial coulombic efficiency of Li{sub 1.2}Mn{sub 0.54}Ni{sub 0.13}Co{sub 0.13}O{sub 2} cathode has been significantly increased and can be compatible with that of the nano-structured Li{sub 4}Ti{sub 5}O{sub 12} anode. The optimization of structure and morphology for both active electrode materials result in their remarkable electrochemical performances in respective lithium half-cells. Ultimately, the rechargeable lithium ion full battery consisting of both electrodes delivers a specific capacity of 99.0 mAh g{sup −1} and a practical energy density of 201 Wh kg{sup −1}, based on the total weight of both active electrode materials. Furthermore, as a promising candidate in the lithium ion battery field, this full battery also achieves highly attractive electrochemical performance with high coulombic efficiency, excellent cycling stability and outstanding rate capability. Thus the proposed battery displays broad practical application prospects for next generation of high-energy lithium ion battery. - Highlights: • The Li{sub 1.2}Mn{sub 0.54}Ni{sub 0.13}Co{sub 0.13}O{sub 2} cathode is surface-treated by Na{sub 2}S{sub 2}O{sub 8}. • The nano-sized Li{sub 4}Ti{sub 5}O{sub 12} anode is obtained by a solid-state method. • A new Li{sub 1.2}Mn{sub 0.54}Ni{sub 0.13}Co{sub 0.13}O{sub 2}/Li{sub 4}Ti{sub 5}O{sub 12} lithium ion battery is developed. • The battery shows high coulombic efficiency, specific capacity and energy density. • The battery shows high capacity retention rate and good high-rate capability.

  14. Surface Modification of Porous Titanium Granules for Improving Bioactivity.

    Science.gov (United States)

    Karaji, Zahra Gorgin; Houshmand, Behzad; Faghihi, Shahab

    The highly porous titanium granules are currently being used as bone substitute material and for bone tissue augmentation. However, they suffer from weak bone bonding ability. The aim of this study was to create a nanostructured surface oxide layer on irregularly shaped titanium granules to improve their bioactivity. This could be achieved using optimized electrochemical anodic oxidation (anodizing) and heat treatment processes. The anodizing process was done in an ethylene glycol-based electrolyte at an optimized condition of 60 V for 3 hours. The anodized granules were subsequently annealed at 450°C for 1 hour. Scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), and x-ray diffraction (XRD) were used to characterize the surface structure and morphology of the granules. The in vitro bioactivity of the samples was evaluated by immersion of specimens in simulated body fluid (SBF) for 1, 2, and 3 weeks. The human osteoblastic sarcoma cell line, MG63, was used to evaluate cell viability on the samples using dimethylthiazol-diphenyl tetrazolium bromide (MTT) assay. The results demonstrated the formation of amorphous nanostructured titanium oxide after anodizing, which transformed to crystalline anatase and rutile phases upon heat treatment. After immersion in SBF, spherical aggregates of amorphous calcium phosphate were formed on the surface of the anodized sample, which turned into crystalline hydroxyapatite on the surface of the anodized annealed sample. No cytotoxicity was detected among the samples. It is suggested that anodic oxidation followed by heat treatment could be used as an effective surface treatment procedure to improve bioactivity of titanium granules implemented for bone tissue repair and augmentation.

  15. Characterisation and behaviour of Ti/TiO2/noble metal anodes

    International Nuclear Information System (INIS)

    Gueneau de Mussy, Jean-Paul; Macpherson, Julie V.; Delplancke, Jean-Luc

    2003-01-01

    The morphology, composition and the electrical and electrochemical behaviour of the anodic microporous layer, prepared by the galvanostatic anodisation of Ti after sparking, followed by galvanostatic deposition of Pt or Ir have been investigated. These electrodes are proposed to function as dimensionally stable anodes (DSAs). For Ti/TiO 2 /Pt electrodes, Pt is deposited within some of the micropores of the oxide film. In contrast, for Ti/TiO 2 /Ir, the metal is deposited preferentially on the top surface. This difference is thought to result from the position of the metal deposition potential with respect to the flat band potential of n-TiO 2 . Optical imaging of both types of DSA suggests that only a few sites on the surface are responsible for electron exchange at the DSA-electrolyte interface. C-AFM measurements of Ti/TiO 2 /Pt samples subjected to long-term anodic polarisation, suggest that the Ti-noble metal contact is progressively insulated by thickening of the TiO 2 barrier layer, promoting passivation of the DSA. For Ir coated anodes, catalytic activity is directly related to the presence of Ir and to the stability of the catalytic oxide layer. Under Cu electrowinning conditions, the electrochemically formed hydrated Ir oxide was found to be catalytically less stable, than the iridium oxide film subjected to a heat treatment

  16. System for supporting conception in the field of surface treatments

    International Nuclear Information System (INIS)

    Evrard, J.M.; Gras, M.

    1989-01-01

    The application of the techniques issued from artificial intelligence for assisting the development of a computer technical memory on a representative subject, which is the surface treatments and coating in tribology, is illustrated. The development of the system is composed of several steps: data acquisition and formatting representation, data validation and software. Particular attention is given to the dialogue between the user and the system. The study shows that the development of the following points are indispensable: the possibility of following the user's reasoning and coming back to previous steps or exploring several parallel ways [fr

  17. Evaluation of Surface Treatment Methods on the Bond Strength of Zirconia Ceramics Systems, Resin Cements and Tooth Surface

    Directory of Open Access Journals (Sweden)

    Akkuş Emek

    2015-07-01

    Full Text Available Objectives: To compare the effects of airborne-particle abrasion (APA and tribochemical silica coating (TSC surface treatment methods on the shear bond strength of zirconia ceramics systems, resin cements and tooth surface

  18. Anodic oxidation of Ta/Fe alloys

    International Nuclear Information System (INIS)

    Mato, S.; Alcala, G.; Thompson, G.E.; Skeldon, P.; Shimizu, K.; Habazaki, H.; Quance, T.; Graham, M.J.; Masheder, D.

    2003-01-01

    The behaviour of iron during anodizing of sputter-deposited Ta/Fe alloys in ammonium pentaborate electrolyte has been examined by transmission electron microscopy, Rutherford backscattering spectroscopy, glow discharge optical emission spectroscopy and X-ray photoelectron spectroscopy. Anodic films on Ta/1.5 at.% Fe, Ta/3 at.% Fe and Ta/7 at.% Fe alloys are amorphous and featureless and develop at high current efficiency with respective formation ratios of 1.67, 1.60 and 1.55 nm V -1 . Anodic oxidation of the alloys proceeds without significant enrichment of iron in the alloy in the vicinity of the alloy/film interface and without oxygen generation during film growth, unlike the behaviour of Al/Fe alloys containing similar concentrations of iron. The higher migration rate of iron species relative to that of tantalum ions leads to the formation of an outer iron-rich layer at the film surface

  19. Lithium batteries, anodes, and methods of anode fabrication

    KAUST Repository

    Li, Lain-Jong; Wu, Feng-Yu; Kumar, Pushpendra; Ming, Jun

    2016-01-01

    Prelithiation of a battery anode carried out using controlled lithium metal vapor deposition. Lithium metal can be avoided in the final battery. This prelithiated electrode is used as potential anode for Li- ion or high energy Li-S battery

  20. Anodization of cast aluminium alloys produced by different casting methods

    Directory of Open Access Journals (Sweden)

    K. Labisz

    2008-08-01

    Full Text Available In this paper the usability of two casting methods, of sand and high pressure cast for the anodization of AlSi12 and AlSi9Cu3 aluminium cast alloys was investigated. With defined anodization parameters like electrolyte composition and temperature, current type and value a anodic alumina surface layer was produced. The quality, size and properties of the anodic layer was investigated after the anodization of the chosen aluminium cast alloys. The Alumina layer was observed used light microscope, also the mechanical properties were measured as well the abrasive wear test was made with using ABR-8251 equipment. The researches included analyze of the influence of chemical composition, geometry and roughness of anodic layer obtained on aluminum casts. Conducted investigations shows the areas of later researches, especially in the direction of the possible, next optimization anodization process of aluminum casting alloys, for example in the range of raising resistance on corrosion to achieve a suitable anodic surface layer on elements for increasing applications in the aggressive environment for example as materials on working building constructions, elements in electronics and construction parts in air and automotive industry.

  1. Efficient treatment of an electroplating wastewater containing heavy metal ions, cyanide, and organics by H2O2 oxidation followed by the anodic Fenton process.

    Science.gov (United States)

    Zhao, Xu; Wang, Haidong; Chen, Fayuan; Mao, Ran; Liu, Huijuan; Qu, Jiuhui

    2013-01-01

    A real electroplating wastewater, containing heavy metals, cyanide, and organic contaminants, was treated by electrocoagulation (EC), H2O2 oxidation, H2O2 pre-oxidation followed by EC, and the anodic Fenton process and the efficacy of the processes was compared. Concentration of cyanide, Cu, Ni, Zn, and Cr was largely decreased by EC within 5 min. When the reaction time was extended, removal of residual cyanide, Cu, and Ni was limited. In H2O2 oxidation, the concentration of cyanide decreased from initial 75 to 12 mg L(-1) in 30 min. The effluents from the H2O2 oxidation were further treated by EC or anodic Fenton. In EC, the concentration of total cyanide, Ni, and Cu decreased to below 0.3, 0.5, and 1.5 mg L(-1), respectively. Removal efficiency of chemical oxygen demand by EC was less than 20.0%. By contrast, there was 73.5% reduction by the anodic Fenton process with 5 mM H2O2 at 30 min; this can be attributed to the oxidation induced by hydroxyl radicals generated by the reaction of H2O2 with the electrogenerated Fe(2+). Meanwhile, residual cyanide, Cu, and Ni can also be efficiently removed. Transformation of organic components in various processes was analyzed using UV-visible and fluorescence excitation-emission spectra.

  2. Lithium batteries, anodes, and methods of anode fabrication

    KAUST Repository

    Li, Lain-Jong

    2016-12-29

    Prelithiation of a battery anode carried out using controlled lithium metal vapor deposition. Lithium metal can be avoided in the final battery. This prelithiated electrode is used as potential anode for Li- ion or high energy Li-S battery. The prelithiation of lithium metal onto or into the anode reduces hazardous risk, is cost effective, and improves the overall capacity. The battery containing such an anode exhibits remarkably high specific capacity and a long cycle life with excellent reversibility.

  3. Self-ordering behavior of nanoporous anodic aluminum oxide (AAO) in malonic acid anodization

    International Nuclear Information System (INIS)

    Lee, W; Nielsch, K; Goesele, U

    2007-01-01

    The self-ordering behavior of anodic aluminum oxide (AAO) has been investigated for anodization of aluminum in malonic acid (H 4 C 3 O 4 ) solution. In the present study it is found that a porous oxide layer formed on the surface of aluminum can effectively suppress catastrophic local events (such as breakdown of the oxide film and plastic deformation of the aluminum substrate), and enables stable fast anodic oxidation under a high electric field of 110-140 V and ∼100 mA cm -2 . Studies on the self-ordering behavior of AAO indicated that the cell homogeneity of AAO increases dramatically as the anodization voltage gets higher than 120 V. Highly ordered AAO with a hexagonal arrangement of the nanopores could be obtained in a voltage range 125-140 V. The current density (i.e., the electric field strength (E) at the bottom of a pore) is an important parameter governing the self-ordering of the nanopores as well as the interpore distance (D int ) for a given anodization potential (U) during malonic acid anodization

  4. Fabrication of superhydrophobic niobium pentoxide thin films by anodization

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Bong-Yong [Future Convergence Ceramic Division, Korea Institute of Ceramic Engineering and Technology, Seoul 153-801 (Korea, Republic of); Jung, Eun-Hye [Future Convergence Ceramic Division, Korea Institute of Ceramic Engineering and Technology, Seoul 153-801 (Korea, Republic of); Department of Chemical Engineering, Inha University, Incheon 402-024 (Korea, Republic of); Kim, Jin-Ho, E-mail: jhkim@kicet.re.kr [Electronic and Optic Materials Division, Korea Institute of Ceramic Engineering and Technology, Seoul 153-801 (Korea, Republic of)

    2014-07-01

    We report a simple method to fabricate a niobium oxide film with a lotus-like micro–nano surface structure. Self-assembled niobium pentoxide (Nb{sub 2}O{sub 5}) films with superhydrophobic property were fabricated by an anodization and a hydrophobic treatment. This process has several advantages such as low cost, simplicity and easy coverage of a large area. The surface of fabricated Nb{sub 2}O{sub 5} film was changed from hydrophilic to superhydrophobic surface by a treatment using fluoroaldyltrimethoxysilane (FAS) solution. This value is considered to be the lowest surface free energy of any solid, based on the alignment of -CF{sub 3} groups on the surface. In particular, among FAS coated surfaces, the micro–nano complex cone structured Nb{sub 2}O{sub 5} film showed the highest water-repellent property with a static contact angle of ca. 162°. This study gives promising routes from biomimetic superhydrophobic surfaces.

  5. Preparation and Anodizing of SiCp/Al Composites with Relatively High Fraction of SiCp

    Science.gov (United States)

    2018-01-01

    By properly proportioned SiC particles with different sizes and using squeeze infiltration process, SiCp/Al composites with high volume fraction of SiC content (Vp = 60.0%, 61.2%, 63.5%, 67.4%, and 68.0%) were achieved for optical application. The flexural strength of the prepared SiCp/Al composites was higher than 483 MPa and the elastic modulus was increased from 174.2 to 206.2 GPa. With an increase in SiC volume fraction, the flexural strength and Poisson's ratio decreased with the increase in elastic modulus. After the anodic oxidation treatment, an oxidation film with porous structure was prepared on the surface of the composite and the oxidation film was uniformly distributed. The anodic oxide growth rate of composite decreased with SiC content increased and linearly increased with anodizing time. PMID:29682145

  6. Influence of anode material on the electrochemical oxidation of 2-naphthol Part 1. Cyclic voltammetry and potential step experiments

    Energy Technology Data Exchange (ETDEWEB)

    Panizza, M.; Cerisola, G

    2003-10-15

    The anodic oxidation of 2-naphthol has been studied by cyclic voltammetry and chronoamperometry, using a range of electrode materials such as Ti-Ru-Sn ternary oxide, lead dioxide and boron-doped diamond (BDD) anodes. The results show that polymeric films, which cause electrode fouling, are formed during oxidation in the potential region of supporting electrolyte stability. IR spectroscopy verified the formation of this organic film. While the Ti-Ru-Sn ternary oxide surface cannot be reactivated, PbO{sub 2} and BDD can be restored to their initial activity by simple anodic treatment in the potential region of electrolyte decomposition. In fact, during the polarization in this region, complex oxidation reactions leading to the complete incineration of polymeric materials can take place on these electrodes due to electrogenerated hydroxyl radicals. Moreover, it was found that BDD deactivation was less pronounced and its reactivation was faster than that of the other electrodes.

  7. Influence of anode material on the electrochemical oxidation of 2-naphthol Part 1. Cyclic voltammetry and potential step experiments

    International Nuclear Information System (INIS)

    Panizza, M.; Cerisola, G.

    2003-01-01

    The anodic oxidation of 2-naphthol has been studied by cyclic voltammetry and chronoamperometry, using a range of electrode materials such as Ti-Ru-Sn ternary oxide, lead dioxide and boron-doped diamond (BDD) anodes. The results show that polymeric films, which cause electrode fouling, are formed during oxidation in the potential region of supporting electrolyte stability. IR spectroscopy verified the formation of this organic film. While the Ti-Ru-Sn ternary oxide surface cannot be reactivated, PbO 2 and BDD can be restored to their initial activity by simple anodic treatment in the potential region of electrolyte decomposition. In fact, during the polarization in this region, complex oxidation reactions leading to the complete incineration of polymeric materials can take place on these electrodes due to electrogenerated hydroxyl radicals. Moreover, it was found that BDD deactivation was less pronounced and its reactivation was faster than that of the other electrodes

  8. Preparation and Anodizing of SiCp/Al Composites with Relatively High Fraction of SiCp.

    Science.gov (United States)

    Wang, Bin; Qu, Shengguan; Li, Xiaoqiang

    2018-01-01

    By properly proportioned SiC particles with different sizes and using squeeze infiltration process, SiCp/Al composites with high volume fraction of SiC content (Vp = 60.0%, 61.2%, 63.5%, 67.4%, and 68.0%) were achieved for optical application. The flexural strength of the prepared SiC p /Al composites was higher than 483 MPa and the elastic modulus was increased from 174.2 to 206.2 GPa. With an increase in SiC volume fraction, the flexural strength and Poisson's ratio decreased with the increase in elastic modulus. After the anodic oxidation treatment, an oxidation film with porous structure was prepared on the surface of the composite and the oxidation film was uniformly distributed. The anodic oxide growth rate of composite decreased with SiC content increased and linearly increased with anodizing time.

  9. Preparation and Anodizing of SiCp/Al Composites with Relatively High Fraction of SiCp

    Directory of Open Access Journals (Sweden)

    Bin Wang

    2018-01-01

    Full Text Available By properly proportioned SiC particles with different sizes and using squeeze infiltration process, SiCp/Al composites with high volume fraction of SiC content (Vp = 60.0%, 61.2%, 63.5%, 67.4%, and 68.0% were achieved for optical application. The flexural strength of the prepared SiCp/Al composites was higher than 483 MPa and the elastic modulus was increased from 174.2 to 206.2 GPa. With an increase in SiC volume fraction, the flexural strength and Poisson’s ratio decreased with the increase in elastic modulus. After the anodic oxidation treatment, an oxidation film with porous structure was prepared on the surface of the composite and the oxidation film was uniformly distributed. The anodic oxide growth rate of composite decreased with SiC content increased and linearly increased with anodizing time.

  10. Effects of sodium tartrate anodizing on fatigue life of TA15 titanium alloy

    Directory of Open Access Journals (Sweden)

    Fu Chunjuan

    2015-08-01

    Full Text Available Anodizing is always used as an effective surface modification method to improve the corrosion resistance and wear resistance of titanium alloy. The sodium tartrate anodizing is a new kind of environmental anodizing method. In this work, the effects of sodium tartrate anodizing on mechanical property were studied. The oxide film was performed on the TA15 titanium alloy using sodium tartrate as the film former. The effects of this anodizing and the traditional acid anodizing on the fatigue life of TA15 alloy were compared. The results show that the sodium tartrate anodizing just caused a slight increase of hydrogen content in the alloy, and had a slight effect on the fatigue life. While, the traditional acid anodizing caused a significant increase of hydrogen content in the substrate and reduced the fatigue life of the alloy significantly.

  11. Histological Evaluation of Nano-Micro Titanium Implant Surface Treatment in Beagle Humerus.

    Science.gov (United States)

    Yun, Kwidug; Kang, Seongsoo; Oh, Gyejeong; Lim, Hyunpil; Lee, Kwangmin; Yang, Hongso; Vang, Mongsook; Park, Sangwon

    2016-02-01

    The objective of this study was to investigate the effects of nano-micro titanium implant surface using histology in beagle dogs. A total of 48 screw-shaped implants (Megagen, Daegu, Korea) which dimensions were 4 mm in diameter and 8.5 mm in length, were used. The implants were classified into 4 groups (n = 12): machined surface (M group), RBM (Resorbable Blasting Media) surface (R group), nano surface which is nanotube formation on the machined surface (MA group) and nano-micro surface which is nanotube formation on the RBM surface (RA group). Anodic oxidation was performed at a constant voltage of 20 V for 10 min using a DC power supply (Fine Power F-3005; SG EMD, Anyang, Korea). The bone blocks were investigated using histology. There was no inflammation around implants, and new bone formation was shown along with the nano-micro titanium implant surfaces. The amount of bone formation was increased depending on time comparing 4 weeks and 12 weeks. At 12 weeks, lamellar bone was more formed along with the nano-micro titanium implant surfaces than 4 weeks. It indicated that nano-micro surface showed good result in terms of osseointegration.

  12. Anodic Fabrication of Ti-Ni-O Nanotube Arrays on Shape Memory Alloy

    Directory of Open Access Journals (Sweden)

    Qiang Liu

    2014-04-01

    Full Text Available Surface modification with oxide nanostructures is one of the efficient ways to improve physical or biomedical properties of shape memory alloys. This work reports a fabrication of highly ordered Ti-Ni-O nanotube arrays on Ti-Ni alloy substrates through pulse anodization in glycerol-based electrolytes. The effects of anodization parameters and the annealing process on the microstructures and surface morphology of Ti-Ni-O were studied using scanning electron microscope and Raman spectroscopy. The electrolyte type greatly affected the formation of nanotube arrays. A formation of anatase phase was found with the Ti-Ni-O nanotube arrays annealed at 450 °C. The oxide nanotubes could be crystallized to rutile phase after annealing treatment at 650 °C. The Ti-Ni-O nanotube arrays demonstrated an excellent thermal stability by keeping their nanotubular structures up to 650 °C.

  13. Silver Nanowires Modified with PEDOT: PSS and Graphene for Organic Light-Emitting Diodes Anode.

    Science.gov (United States)

    Xu, Yilin; Wei, Xiang; Wang, Cong; Cao, Jin; Chen, Yigang; Ma, Zhongquan; You, Ying; Wan, Jixiang; Fang, Xiaohong; Chen, Xiaoyuan

    2017-03-28

    Silver nanowires (AgNWs) networks are promising candidates for the replacement of indium tin oxide (ITO). However, the surface roughness of the AgNWs network is still too high for its application in optoelectronic devices. In this work, we have reduced the surface roughness of the AgNWs networks to 6.4 nm, compared to 33.9 nm of the as-deposited AgNWs network through the hot-pressing process, treatment with poly (3,4ethylenedioxythiophene)-poly (styrenesulfanate), and covered with graphene films. Using this method, we are able to produce AgNWs/PEDOT: PSS/SLG composite films with the transmittance and sheet resistance of 88.29% and 30 Ω/□, respectively. The OLEDs based on the AgNWs/PEDOT: PSS/SLG anodes are comparable to those based on ITO anodes.

  14. The Bioactivity and Photocatalytic Properties of Titania Nanotube Coatings Produced with the Use of the Low-Potential Anodization of Ti6Al4V Alloy Surface

    Science.gov (United States)

    Radtke, Aleksandra; Kozak, Wiesław; Sadowska, Beata; Więckowska-Szakiel, Marzena; Szubka, Magdalena; Talik, Ewa; Pleth Nielsen, Lars; Piszczek, Piotr

    2017-01-01

    Titania nanotube (TNT) coatings were produced using low-potential anodic oxidation of Ti6Al4V substrates in the potential range 3–20 V. They were analysed by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The wettability was estimated by measuring the contact angle when applying water droplets. The bioactivity of the TNT coatings was established on the basis of the biointegration assay (L929 murine fibroblasts adhesion and proliferation) and antibacterial tests against Staphylococcus aureus (ATCC 29213). The photocatalytic efficiency of the TNT films was studied by the degradation of methylene blue under UV irradiation. Among the studied coatings, the TiO2 nanotubes obtained with the use of 5 V potential (TNT5) were found to be the most appropriate for medical applications. The TNT5 sample possessed antibiofilm properties without enriching it by additional antimicrobial agent. Furthermore, it was characterized by optimal biocompatibility, performing better than pure Ti6Al4V alloy. Moreover, the same sample was the most photocatalytically active and exhibited the potential for the sterilization of implants with the use of UV light and for other environmental applications. PMID:28933732

  15. The Bioactivity and Photocatalytic Properties of Titania Nanotube Coatings Produced with the Use of the Low-Potential Anodization of Ti6Al4V Alloy Surface.

    Science.gov (United States)

    Radtke, Aleksandra; Topolski, Adrian; Jędrzejewski, Tomasz; Kozak, Wiesław; Sadowska, Beata; Więckowska-Szakiel, Marzena; Szubka, Magdalena; Talik, Ewa; Pleth Nielsen, Lars; Piszczek, Piotr

    2017-07-26

    Titania nanotube (TNT) coatings were produced using low-potential anodic oxidation of Ti6Al4V substrates in the potential range 3-20 V. They were analysed by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The wettability was estimated by measuring the contact angle when applying water droplets. The bioactivity of the TNT coatings was established on the basis of the biointegration assay (L929 murine fibroblasts adhesion and proliferation) and antibacterial tests against Staphylococcus aureus (ATCC 29213). The photocatalytic efficiency of the TNT films was studied by the degradation of methylene blue under UV irradiation. Among the studied coatings, the TiO₂ nanotubes obtained with the use of 5 V potential (TNT5) were found to be the most appropriate for medical applications. The TNT5 sample possessed antibiofilm properties without enriching it by additional antimicrobial agent. Furthermore, it was characterized by optimal biocompatibility, performing better than pure Ti6Al4V alloy. Moreover, the same sample was the most photocatalytically active and exhibited the potential for the sterilization of implants with the use of UV light and for other environmental applications.

  16. Study for preparation of nanoporous titania on titanium by anodic oxidation

    International Nuclear Information System (INIS)

    Passos, Alessandra Pires

    2014-01-01

    Currently titanium is the most common material used in dental, orthopedic implants and cardiovascular applications. In the mid 1960s, prof. Braenemark and coworkers developed the concept of osseointegration, meaning the direct structural and functional connection between living bone and the surface of artificial implant. Thus, studies on the modification of the implant surface are widely distributed among them are the acid attack, blasting with particles of titanium oxide or aluminum oxide, coating with bioactive materials such as hydroxyapatite, and the anodic oxidation. The focus of this work was to investigate the treatment of titanium surface by anodic oxidation. The aim was to develop a nanoporous titanium oxide overlay with controlled properties over titanium substrates. Recent results have shown that such surface treatment improves the biological interaction at the interface bone-implant besides protecting the titanium further oxidation and allow a faster osseointegration. The anodizing process was done in the potentiostatic mode, using an electrolyte composed of 1.0 mol/L H 3 PO 4 and HF 0.5% m/I. The investigated process parameters were the electrical potential (Va) and the process time (T). The electric potential was varied from 10 V to 30 V and the process time was defined as 1.0 h, 1.5 h or 2.0 h. The treated Ti samples were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive spectroscopy X-ray (EDS), and X-ray diffraction (XRD). The results showed the formation of nanoporous titanium oxide by anodizing with electric potential (Va) in the range of 20 V to 30 V and process time in the range of 1 to 2 hours. The average pore diameter was in the range 94-128 nm. Samples anodized in electric potential lower than 20 V did not show the formation of the nanoporous surface. In the case of Va above 30 V, it was observed the formation of agglomerates of TiO 2 . The results obtained in this study showed no

  17. Cell and method for electrolysis of water and anode

    Science.gov (United States)

    Aylward, J. R. (Inventor)

    1981-01-01

    An electrolytic cell for converting water vapor to oxygen and hydrogen include an anode comprising a foraminous conductive metal substrate with a 65-85 weight percent iridium oxide coating and 15-35 weight percent of a high temperature resin binder. A matrix member contains an electrolyte to which a cathode substantially inert. The foraminous metal member is most desirably expanded tantalum mesh, and the cell desirably includes reservoir elements of porous sintered metal in contact with the anode to receive and discharge electrolyte to the matrix member as required. Upon entry of a water vapor containing airstream into contact with the outer surface of the anode and thence into contact with iridium oxide coating, the water vapor is electrolytically converted to hydrogen ions and oxygen with the hydrogen ions migrating through the matrix to the cathode and the oxygen gas produced at the anode to enrich the air stream passing by the anode.

  18. Influence of the surface treatment of the CMS conductor on its adhesion properties at 300 K and 4.2 K

    CERN Document Server

    Rondeaux, F; Levesy, B; Reytier, M; Safrany, J S

    2001-01-01

    In the 4 T, 12.5 m long, 6 m bore diameter superconducting solenoid for the compact muon solenoid (CMS) experiment at large hadron collider (LHC), the interfaces between the insulation and the conductor or the external cylinder are subjected to high shear forces during the cool down to 4.5 K and the operation phase up to 4 T. Due to the conductive cooling of the coil, the bonding at the different interfaces is a critical point, which is directly related to the quality of the surfaces. The influence of the surface treatment of the conductor on its adhesion properties has been studied at room temperature and in liquid helium at 4.2 K, using a shear force measurement procedure developed in our lab or a peeling test with tape. This paper presents the experimental results obtained on samples treated with solvent cleaning, sandblasting or anodic oxidation under four different sets of experimental conditions, then wrapped with glass tape and impregnated under vacuum. The robustness of the anodic oxidation process, a...

  19. Roughness, surface energy, and superficial damages of CAD/CAM materials after surface treatment.

    Science.gov (United States)

    Strasser, Thomas; Preis, Verena; Behr, Michael; Rosentritt, Martin

    2018-02-05

    The aim of this study was to examine the effects of surface pre-treatment on CAD/CAM materials including ceramics, zirconia, resin-infiltrated ceramic, and resin-based composite. Specimens were made of ten CAD/CAM materials (Celtra Duo, Degudent, D; Vita Suprinity, Vita, D; E.max CAD, Ivoclar-Vivadent, FL; E.max ZirCAD, Ivoclar-Vivadent, FL; Vita Enamic, Vita, D; Cerasmart, GC, B; LAVA Ultimate, 3M, D; SHOFU Block HC, SHOFU, US; Grandio Blocs, VOCO, D; BRILLIANT Crios, Coltene, CH) and pretreated to represent clinical procedures (Hf 20 s/5%; phosphoric acid 20 s/37%; Monobond etch and prime (Ivoclar-Vivadent, FL); water-cooled diamond bur (80 μm; 4 μm); Al 2 O 3 -blasting (50 μm/1 bar, 50 μm/2 bar, 120 μm/1 bar, 120 μm/2 bar); untreated; manufacturer's instructions). SEM-analysis (Phenom, FEI, NL) of the surfaces was performed (magnifications ≤ 10,000×). Roughness values R a , R z (KJ 3D, Keyence, J), and surface energy SE (OCA15 plus, SCA20, DataPhysics, D) were determined (statistics: non-parametric Mann-Whitney U test/Kruskal-Wallis test for independent specimen, α = 0.05). Kruskal-Wallis revealed significant (p CAD/CAM materials require individual pre-treatment for optimized and protective surface activation. Cementation is a key factor for clinical success. Given the variety of available CAD/CAM materials, specific procedures are needed.

  20. Fabrication of Anodic Porous Alumina by Squaric Acid Anodizing

    OpenAIRE

    Kikuchi, Tatsuya; Yamamoto, Tsuyoshi; Natsui, Shungo; Suzuki, Ryosuke O.

    2014-01-01

    The growth behavior of anodic porous alumina formed via anodizing in a new electrolyte, squaric acid (3,4-dihydroxy-3-cyclobutene-1,2-dione), is reported for the first time. A high-purity aluminum foil was anodized in a 0.1 M squaric acid solution at 293 K and a constant applied potential of 100-150 V. Anodic oxides grew on the aluminum foil at applied potentials of 100-120 V, but a burned oxide film was formed at higher voltage. Anodic porous alumina with a cell size of approximately 200-400...

  1. Inert Anode Report

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1999-07-01

    This ASME report provides a broad assessment of open literature and patents that exist in the area of inert anodes and their related cathode systems and cell designs, technologies that are relevant for the advanced smelting of aluminum. The report also discusses the opportunities, barriers, and issues associated with these technologies from a technical, environmental, and economic viewpoint.

  2. Atmospheric pressure dielectric barrier discharges for sterilization and surface treatment

    Energy Technology Data Exchange (ETDEWEB)

    Chin, O. H.; Lai, C. K.; Choo, C. Y.; Wong, C. S.; Nor, R. M. [Plasma Technology Research Centre, Physics Department, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Thong, K. L. [Microbiology Division, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2015-04-24

    Atmospheric pressure non-thermal dielectric barrier discharges can be generated in different configurations for different applications. For sterilization, a parallel-plate electrode configuration with glass dielectric that discharges in air was used. Gram-negative bacteria (Escherichia coli and Salmonella enteritidis) and Gram-positive bacteria (Bacillus cereus) were successfully inactivated using sinusoidal high voltage of ∼15 kVp-p at 8.5 kHz. In the surface treatment, a hemisphere and disc electrode arrangement that allowed a plasma jet to be extruded under controlled nitrogen gas flow (at 9.2 kHz, 20 kVp-p) was applied to enhance the wettability of PET (Mylar) film.

  3. Evaluation of chemical surface treatment methods for mitigation of PWSCC

    International Nuclear Information System (INIS)

    Dame, C.; Marks, C.; Olender, A.; Farias, J.

    2015-01-01

    As part of its mission to propose innovative and safe technologies to mitigate Primary Water Stress Corrosion Cracking (PWSCC) in Pressurized Water Reactors (PWR), EPRI recently initiated a program to evaluate potential new chemical surface treatments that might delay the occurrence of PWSCC such that no failure of components would be observed during their lifetime. Among the initial screening of more than thirty technologies, seven were selected for a more detailed review. The selected technologies were: nickel and nickel alloy plating, organic inhibitors, chromium-based inhibitors, silicon carbide, titanium-based inhibitors, rare earth metal (REM)-based inhibitors and encapsulation. The conclusions of the review of these technologies were that two of them were worth pursuing, titanium-based and REM-based inhibitors, and that evaluating the radiological consequences of injecting these products in the primary system, as well as assessing their efficacy to mitigate PWSCC, should be prioritized as the next required steps in qualification for implementation. (authors)

  4. Application of nitrogen plasma immersion ion implantation to titanium nasal implants with nanonetwork surface structure

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Ying-Sui; Yang, Wei-En [Department of Dentistry, National Yang-Ming University, Taipei 112, Taiwan (China); Zhang, Lan [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Zhu, Hongqin [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Lan, Ming-Ying [Division of Rhinology, Department of Otolaryngology Head and Neck Surgery, Taipei Veterans General Hospital, Taipei 112, Taiwan and School of Medicine, National Yang-Ming University, Taipei 112, Taiwan (China); Lee, Sheng-Wei [Institute of Materials Science and Engineering, National Central University, Taoyuan 320, Taiwan (China); Huang, Her-Hsiung, E-mail: hhhuang@ym.edu.tw [Department of Dentistry, National Yang-Ming University, Taipei 112, Taiwan (China); Institute of Oral Biology, National Yang-Ming University, Taipei 112, Taiwan (China); Graduate Institute of Basic Medical Science, China Medical University, Taichung 404, Taiwan (China); Department of Medical Research, China Medical University Hospital, Taichung 407, Taiwan (China); Department of Bioinformatics and Medical Engineering, Asia University, Taichung 413, Taiwan (China); Department of Stomatology, Taipei Veterans General Hospital, Taipei 112, Taiwan (China)

    2016-07-15

    In nasal reconstruction, the response of cells to titanium (Ti) implants is mainly determined by surface features of the implant. In a pilot study, the authors applied electrochemical anodization to Ti surfaces in an alkaline solution to create a network of nanoscale surface structures. This nanonetwork was intended to enhance the responses of primary human nasal epithelial cell (HNEpC) to the Ti surface. In this study, the authors then treated the anodized, nanonetwork-structured Ti surface using nitrogen plasma immersion ion implantation (NPIII) in order to further improve the HNEpC response to the Ti surface. Subsequently, surface characterization was performed to elucidate morphology, roughness, wettability, and chemistry of specimens. Cytotoxicity, blood, and HNEpC responses were also evaluated. Our results demonstrate that NPIII treatment led to the formation of a noncytotoxic TiN-containing thin film (thickness <100 nm) on the electrochemically anodized Ti surface with a nanonetwork-structure. NPIII treatment was shown to improve blood clotting and the adhesion of platelets to the anodized Ti surface as well as the adhesion and proliferation of hNEpC. This research spreads our understanding of the fact that a TiN-containing thin film, produced using NPIII treatment, could be used to improve blood and HNEpC responses to anodized, nanonetwork-structured Ti surfaces in nasal implant applications.

  5. Infiltration of surface mined land reclaimed by deep tillage treatments

    International Nuclear Information System (INIS)

    Chong, S.K.; Cowsert, P.

    1994-01-01

    Surface mining of coal leads to the drastic disturbance of soils. Compaction of replaced subsoil and topsoil resulting from hauling, grading, and leveling procedures produces a poor rooting medium for crop growth. Soil compaction results in high bulk density, low macroporosity, poor water infiltration capacity, and reduced elongation of plant roots. In the United States, Public Law 95-87 mandates that the rooting medium of mined soils have specific textural characteristics and be graded and shaped to a topography similar to premining conditions. Also, crop productivity levels equivalent to those prior to mining must be achieved, especially for prime farmland. Alleviation of compaction has been the major focus of reclamation, and recently new techniques to augment the rooting zone with deep-ripping and loosening equipment have come to the forefront. Several surface mine operators in the Illinois coal basin are using deep tillage equipment that is capable of loosening soils to greater depths than is possible with conventional farm tillage equipment. Information on the beneficial effects of these loosening procedures on soil hydrological properties, such as infiltration, runoff potential, erosion, and water retention, is extremely important for future mined land management. However, such information is lacking. In view of the current yield demonstration regulation for prime farmland and other unmined soils, it is important that as much information as possible be obtained concerning the effect of deep tillage on soil hydrologic properties. The objectives of this study are: (1) to compare infiltration rates and related soil physical properties of mined soils reclaimed by various deep tillage treatments and (2) to study the temporal variability of infiltration and related physical properties of the reclaimed mined soil after deep tillage treatment

  6. The anodizing behavior of aluminum in malonic acid solution and morphology of the anodic films

    Science.gov (United States)

    Ren, Jianjun; Zuo, Yu

    2012-11-01

    The anodizing behavior of aluminum in malonic acid solution and morphology of the anodic films were studied. The voltage-time response for galvanostatic anodization of aluminum in malonic acid solution exhibits a conventional three-stage feature but the formation voltage is much higher. With the increase of electrolyte concentration, the electrolyte viscosity increases simultaneously and the high viscosity decreases the film growth rate. With the concentration increase of the malonic acid electrolyte, the critical current density that initiates local "burning" on the sample surface decreases. For malonic acid anodization, the field-assisted dissolution on the oxide surface is relatively weak and the nucleation of pores is more difficult, which results in greater barrier layer thickness and larger cell dimension. The embryo of the porous structure of anodic film has been created within the linear region of the first transient stage, and the definite porous structure has been established before the end of the first transient stage. The self-ordering behavior of the porous film is influenced by the electrolyte concentration, film thickness and the applied current density. Great current density not only improves the cell arrangement order but also brings about larger cell dimension.

  7. Studies on the treatment of surface water using rajma seeds

    Directory of Open Access Journals (Sweden)

    Merlin S. Babitha

    2018-03-01

    Full Text Available Indiscriminate disposal of wastewater with suspended solids have led to higher amount of pollution to the natural water bodies. Turbidity removal becomes an essential part in the water treatment when surface water is used for drinking purpose, this can be achieved by means of coagulation process. Coagulation process is the dosing of a coagulant in water, resulting in the destabilization of negatively charged particles. Commercial coagulants which were widely used can synthesize by-products in turn may pollute the environment and deteriorate the ecosystem at a slow rate. So, now-a-days natural coagulants are used as a potential substitute because it’s biodegradable, ecofriendly and non-toxic. In this study, the turbid surface water samples were treated using powdered seeds of Rajma (natural coagulant followed by variations in dosage, settling time and pH were also studied. From the results obtained, it was found that the Rajma seeds powder achieved 48.80% efficiency for 0.5 g/l of optimum dose at pH 6 for 20 min settling time respectively.

  8. Studies on the treatment of surface water using rajma seeds

    Science.gov (United States)

    Merlin, S. Babitha; Abirami, M.; Kumar, R. Suresh

    2018-03-01

    Indiscriminate disposal of wastewater with suspended solids have led to higher amount of pollution to the natural water bodies. Turbidity removal becomes an essential part in the water treatment when surface water is used for drinking purpose, this can be achieved by means of coagulation process. Coagulation process is the dosing of a coagulant in water, resulting in the destabilization of negatively charged particles. Commercial coagulants which were widely used can synthesize by-products in turn may pollute the environment and deteriorate the ecosystem at a slow rate. So, now-a-days natural coagulants are used as a potential substitute because it's biodegradable, ecofriendly and non-toxic. In this study, the turbid surface water samples were treated using powdered seeds of Rajma (natural coagulant) followed by variations in dosage, settling time and pH were also studied. From the results obtained, it was found that the Rajma seeds powder achieved 48.80% efficiency for 0.5 g/l of optimum dose at pH 6 for 20 min settling time respectively.

  9. Electrochemical degradation of clofibric acid in water by anodic oxidation

    International Nuclear Information System (INIS)

    Sires, Ignasi; Cabot, Pere Lluis; Centellas, Francesc; Garrido, Jose Antonio; Rodriguez, Rosa Maria; Arias, Conchita; Brillas, Enric

    2006-01-01

    Aqueous solutions containing the metabolite clofibric acid (2-(4-chlorophenoxy)-2-methylpropionic acid) up to close to saturation in the pH range 2.0-12.0 have been degraded by anodic oxidation with Pt and boron-doped diamond (BDD) as anodes. The use of BDD leads to total mineralization in all media due to the efficient production of oxidant hydroxyl radical (·OH). This procedure is then viable for the treatment of wastewaters containing this compound. The effect of pH, apparent current density, temperature and metabolite concentration on the degradation rate, consumed specific charge and mineralization current efficiency has been investigated. Comparative treatment with Pt yields poor decontamination with complete release of stable chloride ion. When BDD is used, this ion is oxidized to Cl 2 . Clofibric acid is more rapidly destroyed on Pt than on BDD, indicating that it is more strongly adsorbed on the Pt surface enhancing its reaction with ·OH. Its decay kinetics always follows a pseudo-first-order reaction and the rate constant for each anode increases with increasing apparent current density, being practically independent of pH and metabolite concentration. Aromatic products such as 4-chlorophenol, 4-chlorocatechol, 4-chlororesorcinol, hydroquinone, p-benzoquinone and 1,2,4-benzenetriol are detected by gas chromatography-mass spectrometry (GC-MS) and reversed-phase chromatography. Tartronic, maleic, fumaric, formic, 2-hydroxyisobutyric, pyruvic and oxalic acids are identified as generated carboxylic acids by ion-exclusion chromatography. These acids remain stable in solution using Pt, but they are completely converted into CO 2 with BDD. A reaction pathway for clofibric acid degradation involving all these intermediates is proposed

  10. Electrochemical degradation of clofibric acid in water by anodic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Sires, Ignasi [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Cabot, Pere Lluis [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Centellas, Francesc [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Garrido, Jose Antonio [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Rodriguez, Rosa Maria [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Arias, Conchita [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Brillas, Enric [Laboratori de Ciencia i Tecnologia Electroquimica de Materials, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain)]. E-mail: brillas@ub.edu

    2006-10-05

    Aqueous solutions containing the metabolite clofibric acid (2-(4-chlorophenoxy)-2-methylpropionic acid) up to close to saturation in the pH range 2.0-12.0 have been degraded by anodic oxidation with Pt and boron-doped diamond (BDD) as anodes. The use of BDD leads to total mineralization in all media due to the efficient production of oxidant hydroxyl radical ({center_dot}OH). This procedure is then viable for the treatment of wastewaters containing this compound. The effect of pH, apparent current density, temperature and metabolite concentration on the degradation rate, consumed specific charge and mineralization current efficiency has been investigated. Comparative treatment with Pt yields poor decontamination with complete release of stable chloride ion. When BDD is used, this ion is oxidized to Cl{sub 2}. Clofibric acid is more rapidly destroyed on Pt than on BDD, indicating that it is more strongly adsorbed on the Pt surface enhancing its reaction with {center_dot}OH. Its decay kinetics always follows a pseudo-first-order reaction and the rate constant for each anode increases with increasing apparent current density, being practically independent of pH and metabolite concentration. Aromatic products such as 4-chlorophenol, 4-chlorocatechol, 4-chlororesorcinol, hydroquinone, p-benzoquinone and 1,2,4-benzenetriol are detected by gas chromatography-mass spectrometry (GC-MS) and reversed-phase chromatography. Tartronic, maleic, fumaric, formic, 2-hydroxyisobutyric, pyruvic and oxalic acids are identified as generated carboxylic acids by ion-exclusion chromatography. These acids remain stable in solution using Pt, but they are completely converted into CO{sub 2} with BDD. A reaction pathway for clofibric acid degradation involving all these intermediates is proposed.

  11. An experimental study of aluminium electrowinning using a nickel-based hydrogen diffusion anode

    International Nuclear Information System (INIS)

    Namboothiri, Sankar; Taylor, Mark P.; Chen, John J.J.; Hyland, Margaret M.; Cooksey, Mark A.

    2011-01-01

    Research highlights: → Measurable depolarisation of the anode potential and formation of water vapour. → Metallic aluminium was found on the spent cathode. → HF emissions can be minimised by conducting the electrolysis at 750 o C. → The nickel based anode surface corroded during electrolysis. → Its application is constrained by the material limitation of the porous anode. - Abstract: Laboratory scale electrolysis experiments were conducted to investigate the electrowinning of aluminium using hydrogen diffusion anodes. A potassium-based electrolyte (KF-AlF 3 -Al 2 O 3 ), porous nickel alloy anode and molybdenum disk cathode were used in experiments at 750 o C. Hydrogen gas was supplied to the anode/electrolyte interface through the porous anode. Experiments were conducted in potentiostatic, galvanostatic and galvanodynamic modes. There was a measurable depolarisation of the anode potential and also anode reaction of hydrogen and oxygen ions in the bath to form water vapour was confirmed by the water vapour condensate found at the electrolysis exit gas pipe. Metallic aluminium was found on the spent cathode. The experiments conducted in the galvanodynamic mode suggested that the rate limiter for hydrogen oxidation was the availability of surface hydrogen at the anode/electrolyte interface. The anode surface corroded during electrolysis and impurities were found both in the molten bath and on the cathode.

  12. Plasma treatments of wool fiber surface for microfluidic applications

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, So-Hyoun; Hwang, Ki-Hwan; Lee, Jin Su [Department of Chemistry, Sungkyunkwan University, 440-746 Suwon (Korea, Republic of); Boo, Jin-Hyo, E-mail: jhboo@skku.edu [Department of Chemistry, Sungkyunkwan University, 440-746 Suwon (Korea, Republic of); Yun, Sang H., E-mail: shy@kth.se [Institute of Basic Science, Sungkyunkwan University, 440-746 Suwon (Korea, Republic of)

    2015-09-15

    Highlights: • We used atmospheric plasma for tuning the wettability of wool fibers. • The wicking rates of the wool fibers increased with increasing treatment time. • The increasing of wettability results in removement of fatty acid on the wool surface. - Abstract: Recent progress in health diagnostics has led to the development of simple and inexpensive systems. Thread-based microfluidic devices allow for portable and inexpensive field-based technologies enabling medical diagnostics, environmental monitoring, and food safety analysis. However, controlling the flow rate of wool thread, which is a very important part of thread-based microfluidic devices, is quite difficult. For this reason, we focused on thread-based microfluidics in the study. We developed a method of changing the wettability of hydrophobic thread, including wool thread. Thus, using natural wool thread as a channel, we demonstrate herein that the manipulation of the liquid flow, such as micro selecting and micro mixing, can be achieved by applying plasma treatment to wool thread. In addition to enabling the flow control of the treated wool channels consisting of all natural substances, this procedure will also be beneficial for biological sensing devices. We found that wools treated with various gases have different flow rates. We used an atmospheric plasma with O{sub 2}, N{sub 2} and Ar gases.

  13. Desensitization of stainless steels by laser surface heat-treatment

    Energy Technology Data Exchange (ETDEWEB)

    Nakao, Yoshikuni; Nishimoto, Kazutoshi

    1987-11-01

    Laser heating was applied for the desensitization heat-treatment of the surface layer in the sensitized HAZ of Type 304 stainless steel. The degree of sensitization was examined by EPR technique and the 10 % oxalic acid electrolytic etch test. The CO/sub 2/ laser with maximum power of 1.5 kW was used for heat-treatment. Time-Temperature-Desensitization diagram (TTDS diagram) for sensitized Type 304 stainless steels were developed by calculation assuming the chromium diffusion control for desensitization which might occur when the chromium depleted zone was healed up due to dissolution of chromium carbide and chromium diffusion from the matrix being heated at the solution annealing temperatures. TTDS diagrams calculated agree fairly well with ones determined by corrosion tests. Laser irradiation conditions (e.g., Laser power, beam diameter and traveling velocity) required for desensitization of sensitized Type 304 stainless steels were calculated using additivity rule from the TTDS diagram calculated and theoretical thermal curve of laser heating derived from the heat conduction theory. After laser beam irradiated under an optimum condition predicted by calculation, the sensitized HAZ of Type 304 stainless steel restored complete resistance to intergranular corrosion.

  14. The effects of subcutaneous injection of nicotine on osseointegration of machined and anodized implants in rabbits.

    Science.gov (United States)

    Linden, Maria Salete Sandini; Bittencourt, Marcos Eugênio de; Carli, João Paulo De; Miyagaki, Daniela Cristina; Santos, Pâmela Letícia Dos; Paranhos, Luiz Renato; Groppo, Francisco Carlos; Ramacciato, Juliana Cama

    2018-01-01

    To evaluate the influence of subcutaneous injection nicotine in osseointegration process on different implant surfaces. Twenty-two male rabbits were distributed into two groups according to the subcutaneous injections: (1) nicotine 3 mg/day/kg and (2) 0.9 % NaCI 3 mL/day/kg, three times a day; subgroups were then designated-machined and anodized implants were placed in the right and left tibia bones, respectively. The animals were submitted euthanasia after periods of eight weeks to determine nicotine and cotinine levels, alkaline phosphatase and biomechanical analysis. The plasmatic levels of nicotine and cotinine were 0.5 ± 0.28 ng/mL and 9.5 ± 6.51 ng/mL, respectively. The alkaline phosphatase analyses in blood levels in control group were observed 40.8 ± 11.88 UI/L and 40.75 ± 12.46 UI/L, for the surfaces machined and anodized, respectively. In the test group was observed levels 37.9 ± 4.84 UI/L, for both implant surfaces. No significant differences were observed between control and test groups and between the implant surfaces regarding alkaline phosphatase blood levels. For biomechanics, no significant differences were observed in control group between the machined (25±8.46 Ncm) or anodized (31.2 ± 6.76 Ncm) implants. However, the treatment with nicotine induced higher torque than control in both machined (38.3 ± 13.52 Ncm) and anodized (35.5 ± 14.17 Ncm) implants, with p = 0.0024 and p = 0.0121, respectively. Subcutaneous injection of nicotine following implant insertion didn't have effect on osseointegration, independently from the implant surface.

  15. Reduction mechanisms of ethylene carbonate on si anodes of lithium-ion batteries: effects of degree of lithiation and nature of exposed surface.

    Science.gov (United States)

    Martinez de la Hoz, Julibeth M; Leung, Kevin; Balbuena, Perla B

    2013-12-26

    Ab initio molecular dynamics simulations are used to identify mechanisms of reduction of ethylene carbonate on Si surfaces at various degrees of lithiation, where the low-coordinated surface Si atoms are saturated with O, OH, or H functional groups. The lowest Si content surfaces are represented by quasi-amorphous LiSi4 and LiSi2; intermediate lithiation is given by LiSi crystalline facets, and the highest Li content is studied through Li13Si4 surfaces. It is found that ethylene carbonate (EC) reduction mechanisms depend significantly on the degree of lithiation of the surface. On LiSi surfaces EC is reduced according to two different two-electron mechanisms (one simultaneous and one sequential), which are independent of specific surface functionalization or nature of exposed facets. On the less lithiated surfaces, the simultaneous two-electron reduction is found more frequently. In that mechanism, the EC reduction is initiated by the formation of a C-Si bond that allows adsorption of the intact molecule to the surface and is followed by electron transfer and ring-opening. Strongly lithiated Li13Si4 surfaces are found to be highly reactive. Reduction of adsorbed EC molecules occurs via a four-electron mechanism yielding as reduction products CO(2-) and O(C2H4)O(2-). Direct transfer of two electrons to EC molecules in liquid phase is also possible, resulting in the presence of O(C2H4)OCO(2-) anions in the liquid phase.

  16. Electrochemical evaluation of Ti/TiO{sub 2}-polyaniline anodes for microbial fuel cells using hypersaline microbial consortia for synthetic-wastewater treatment

    Energy Technology Data Exchange (ETDEWEB)

    Benetton, X.D.; Navarro-Avila, S.G. [Univ. Autonoma de Yucatan, Yucatan (Mexico). Biotecnologia y Bioingenieria; Carrera-Figueiras, C. [Univ. Autonoma de Yucatan, Yucatan (Mexico). Quimica Fundamental y Aplicada

    2010-07-01

    This paper described the development of a titanium (Ti/TiO{sub 2}) polyaniline composite electrode. The electrode was designed for use with a microbial fuel cell (MFC) that generated electricity through the microbial biodegradation of organic compounds. A modified NBAF medium was used with a 20 mM acetate as an electron donor and 53 mM fumarate as an electron acceptor for a period of 96 hours at 37 degrees C. Strains were cultured under strict anaerobic conditions. Two microbial cultures were used: (1) pure cultures of Geobacter sulfur-reducens; and (2) an uncharacterized stable microbial consortia isolated from hypersaline swamp sediments. The anodes were made with an emeraldine form of PANI deposited over Ti/TiO{sub 2} electrodes. Electrochemical impedance spectroscopy (EIS) monitoring was used to determine the open circuit potential of the MFC. Negative real impedances were obtained and reproduced in all systems studied with the Ti/TiO{sub 2}-PANI anodes. The highest power density was obtained using the Geobacter sulfur-reducens culture. Further research is needed to study the mechanisms that contribute to the occurrence of negative real impedances. 23 refs., 1 tab., 5 figs.

  17. Perovskites synthesis to SOFC anodes

    International Nuclear Information System (INIS)

    Wendler, L.P.; Chinelatto, A.L.; Chinelatto, A.S.A.; Ramos, K.

    2012-01-01

    Perovskite structure materials containing lanthanum have been widely applied as solid oxide fuel cells (SOFCs) electrodes, due to its electrical properties. Was investigated the obtain of the perovskite structure LaCr 0,5 Ni 0,5 O 3 , by Pechini method, and its suitability as SOFC anode. The choice of this composition was based on the stability provided by chromium and the catalytic properties of nickel. After preparing the resins, the samples were calcined at 300 deg C, 600 deg C, 700 deg C and 850 deg C. The resulting powders were characterized by X-ray diffraction to determine the existing phases. Furthermore, were performed other analysis, like X-ray fluorescence, He pycnometry, specific surface area by BET isotherm and scanning electronic microscopy (author)

  18. Superhydrophilicity of novel anodic alumina nanofibers films and their formation mechanism

    Science.gov (United States)

    Peng, Rong; Yang, Wulin; Fu, Licai; Zhu, Jiajun; Li, Deyi; Zhou, Lingping

    2017-06-01

    A novel anodic alumina nanofibers structure, which is different from the traditional porous anodic structure, has been quickly fabricated via anodizing in a new electrolyte, pyrophosphoric acid. The effects of the solution concentration and the anodizing time on the formation of the anodic alumina nanofibers were analyzed. The results show that the nanostructure of anodic alumina can change to the nanofiber oxide from the porous oxide by increasing the solution concentration. Prolonging the anodizing time is beneficial to obtain alumina nanofibers at high solution concentration. Growth behavior of the alumina nanofibers was also discussed by scanning electron microscopy observations. Owing to the unique hexagonal structure of anodic alumina as well as the preferential chemical dissolution between the porous anodic alumina and the anodic alumina nanotips, the slightly soluble anodic alumina nanotips could form novel alumina nanofibers during anodizing. The results show that the nanofibers-covered aluminum surface exhibits superhydrophilic property, with a near-zero water contact angle. Such alumina nanofibers with superhydrophilic property could be used for various potential applications.

  19. Improved adhesion of Ag NPs to the polyethylene terephthalate surface via atmospheric plasma treatment and surface functionalization

    Science.gov (United States)

    Shen, Tao; Liu, Yong; Zhu, Yan; Yang, De-Quan; Sacher, Edward

    2017-07-01

    Ag nanoparticles (NPs) have been widely applied, as important antibacterial materials, on textile and polymer surfaces. However, their adhesion to nonreactive polymer surfaces is generally too weak for many applications. Here, we propose a two-step process, atmospheric plasma treatment followed by a surface chemical modification process, which enhances their adhesion to polyethylene terephthalate (PET) surfaces. We found that, compared to either plasma treatments or surface chemical functionalizations, alone, this combination greatly enhanced their adhesion. The plasma treatment resulted in an increase of active sites (sbnd OH, sbnd CHdbnd O and COOH) at the PET surface, permitting increased bonding to 3-aminopropyltriethoxysilane (APTES), whose sbnd NH2 groups were then able to form a bonding complex with the Ag NPs.

  20. Anode Supported Solid Oxide Fuel Cells - Deconvolution of Degradation into Cathode and Anode Contributions

    DEFF Research Database (Denmark)

    Hagen, Anke; Liu, Yi-Lin; Barfod, Rasmus

    2007-01-01

    The degradation of anode supported cells was studied over 1500 h as function of cell polarization either in air or oxygen on the cathode. Based on impedance analysis, contributions of anode and cathode to the increase of total resistance were assigned. Accordingly, the degradation rates...... of the cathode were strongly dependent on the pO(2); they were significantly smaller when testing in oxygen compared to air. Microstructural analysis of the cathode/electrolyte interface of a not-tested reference cell carried out after removal of the cathode showed sharp craters on the electrolyte surface where...

  1. Investigation of mechanism of anode plasma formation in ion diode with dielectric anode

    International Nuclear Information System (INIS)

    Pushkarev, A.

    2015-01-01

    The results of investigation of the anode plasma formation in a diode with a passive anode in magnetic insulation mode are presented. The experiments have been conducted using the BIPPAB-450 ion accelerator (350–400 kV, 6–8 kA, 80 ns) with a focusing conical diode with B r external magnetic field (a barrel diode). For analysis of plasma formation at the anode and the distribution of the ions beam energy density, infrared imaging diagnostics (spatial resolution of 1–2 mm) is used. For analysis of the ion beam composition, time-of-flight diagnostics (temporal resolution of 1 ns) were used. Our studies have shown that when the magnetic induction in the A-C gap is much larger than the critical value, the ion beam energy density is close to the one-dimensional Child-Langmuir limit on the entire working surface of the diode. Formation of anode plasma takes place only by the flashover of the dielectric anode surface. In this mode, the ion beam consists primarily of singly ionized carbon ions, and the delay of the start of formation of the anode plasma is 10–15 ns. By reducing the magnetic induction in the A-C gap to a value close to the critical one, the ion beam energy density is 3–6 times higher than that calculated by the one-dimensional Child-Langmuir limit, but the energy density of the ion beam is non-uniform in cross-section. In this mode, the anode plasma formation occurs due to ionization of the anode material with accelerated electrons. In this mode, also, the delay in the start of the formation of the anode plasma is much smaller and the degree of ionization of carbon ions is higher. In all modes occurred effective suppression of the electronic component of the total current, and the diode impedance was 20–30 times higher than the values calculated for the mode without magnetic insulation of the electrons. The divergence of the ion beam was 4.5°–6°

  2. Fabrication of porous anodic alumina using normal anodization and pulse anodization

    Science.gov (United States)

    Chin, I. K.; Yam, F. K.; Hassan, Z.

    2015-05-01

    This article reports on the fabrication of porous anodic alumina (PAA) by two-step anodizing the low purity commercial aluminum sheets at room temperature. Different variations of the second-step anodization were conducted: normal anodization (NA) with direct current potential difference; pulse anodization (PA) alternate between potential differences of 10 V and 0 V; hybrid pulse anodization (HPA) alternate between potential differences of 10 V and -2 V. The method influenced the film homogeneity of the PAA and the most homogeneous structure was obtained via PA. The morphological properties are further elucidated using measured current-transient profiles. The absent of current rise profile in PA indicates the anodization temperature and dissolution of the PAA structure were greatly reduced by alternating potential differences.

  3. Polymerization by plasma: surface treatment and plasma simulation

    International Nuclear Information System (INIS)

    Morales C, J.

    2001-01-01

    One of the general objectives that are developed by the group of polymers semiconductors in the laboratory of polymers of the UAM-Iztapalapa is to study the surface treatment for plasma of different materials. Framed in this general objective, in this work three lines of investigation have been developed, independent one of other that converge in the general objective. The first one tries about the modeling one and evaluation of the microscopic parameters of operation of the polymerization reactor. The second are continuation of the study of conductive polymers synthesized by plasma and the third are an application of the treatment for plasma on natural fibers. In the first one it lines it is carried out the characterization and simulation of the parameters of operation of the polymerization reactor for plasma. They are determined the microscopic parameters of operation of the reactor experimentally like they are the electronic temperature, the potential of the plasma and the density average of electrons using for it an electrostatic Langmuir probe. In the simulation, starting from the Boltzmann transport equation it thinks about the flowing pattern and the electronic temperature, the ions density is obtained and of electrons. The data are compared obtained experimentally with the results of the simulation. In second line a study is presented about the influence of the temperature on the electric conductivity of thin films doped with iodine, of poly aniline (P An/I) and poly pyrrole (P Py/I). The films underwent heating-cooling cycles. The conductivity of P An/I and P Py/I in function of the temperature it is discussed based on the Arrhenius model, showing that it dominates the model of homogeneous conductivity. It is also synthesized a polymer bi-layer of these two elements and a copolymer random poly aniline-poly pyrrole, of the first one it the behavior of its conductivity discusses with the temperature and of the second, the conductivity is discussed in

  4. Surface treatment of glass substrates for the preparation of long-lived carbon stripper foils

    International Nuclear Information System (INIS)

    Takeuchi, Suehiro; Takekoshi, Eiko

    1981-02-01

    Glass substrates having uniformly distributed microscopic grains on the surfaces are useful to make long-lived carbon stripper foils for heavy ions. A method of surface treatment of glass substrates to form the surface structure is described. This method consists of precipitation of glass components, such as soda, onto the surfaces in a hot and humid atmosphere and a fogging treatment of forming microscopic grains of the precipitated substances. Some results of studies on the treatment conditions are also presented. (author)

  5. Liquid Silicon Pouch Anode

    Science.gov (United States)

    2017-09-06

    Number 15/696,426 Filing Date 6 September 2017 Inventor Charles J. Patrissi et al Address any questions concerning this matter to the...silicon-based anodes during cycling, lithium insertion and deinsertion. Mitigation of this problem has long been sought and will result in improved...design shown. [0032] It will be understood that many additional changes in the details, materials, steps and arrangement of parts, which have been

  6. Apatite Formation and Biocompatibility of a Low Young's Modulus Ti-Nb-Sn Alloy Treated with Anodic Oxidation and Hot Water.

    Directory of Open Access Journals (Sweden)

    Hidetatsu Tanaka

    Full Text Available Ti-6Al-4V alloy is widely prevalent as a material for orthopaedic implants because of its good corrosion resistance and biocompatibility. However, the discrepancy in Young's modulus between metal prosthesis and human cortical bone sometimes induces clinical problems, thigh pain and bone atrophy due to stress shielding. We designed a Ti-Nb-Sn alloy with a low Young's modulus to address problems of stress disproportion. In this study, we assessed effects of anodic oxidation with or without hot water treatment on the bone-bonding characteristics of a Ti-Nb-Sn alloy. We examined surface analyses and apatite formation by SEM micrographs, XPS and XRD analyses. We also evaluated biocompatibility in experimental animal models by measuring failure loads with a pull-out test and by quantitative histomorphometric analyses. By SEM, abundant apatite formation was observed on the surface of Ti-Nb-Sn alloy discs treated with anodic oxidation and hot water after incubation in Hank's solution. A strong peak of apatite formation was detected on the surface using XRD analyses. XPS analysis revealed an increase of the H2O fraction in O 1s XPS. Results of the pull-out test showed that the failure loads of Ti-Nb-Sn alloy rods treated with anodic oxidation and hot water was greater than those of untreated rods. Quantitative histomorphometric analyses indicated that anodic oxidation and hot water treatment induced higher new bone formation around the rods. Our findings indicate that Ti-Nb-Sn alloy treated with anodic oxidation and hot water showed greater capacity for apatite formation, stronger bone bonding and higher biocompatibility for osteosynthesis. Ti-Nb-Sn alloy treated with anodic oxidation and hot water treatment is a promising material for orthopaedic implants enabling higher osteosynthesis and lower stress disproportion.

  7. Apatite Formation and Biocompatibility of a Low Young’s Modulus Ti-Nb-Sn Alloy Treated with Anodic Oxidation and Hot Water

    Science.gov (United States)

    Tanaka, Hidetatsu; Mori, Yu; Noro, Atsushi; Kogure, Atsushi; Kamimura, Masayuki; Yamada, Norikazu; Hanada, Shuji; Masahashi, Naoya; Itoi, Eiji

    2016-01-01

    Ti-6Al-4V alloy is widely prevalent as a material for orthopaedic implants because of its good corrosion resistance and biocompatibility. However, the discrepancy in Young’s modulus between metal prosthesis and human cortical bone sometimes induces clinical problems, thigh pain and bone atrophy due to stress shielding. We designed a Ti-Nb-Sn alloy with a low Young’s modulus to address problems of stress disproportion. In this study, we assessed effects of anodic oxidation with or without hot water treatment on the bone-bonding characteristics of a Ti-Nb-Sn alloy. We examined surface analyses and apatite formation by SEM micrographs, XPS and XRD analyses. We also evaluated biocompatibility in experimental animal models by measuring failure loads with a pull-out test and by quantitative histomorphometric analyses. By SEM, abundant apatite formation was observed on the surface of Ti-Nb-Sn alloy discs treated with anodic oxidation and hot water after incubation in Hank’s solution. A strong peak of apatite formation was detected on the surface using XRD analyses. XPS analysis revealed an increase of the H2O fraction in O 1s XPS. Results of the pull-out test showed that the failure loads of Ti-Nb-Sn alloy rods treated with anodic oxidation and hot water was greater than those of untreated rods. Quantitative histomorphometric analyses indicated that anodic oxidation and hot water treatment induced higher new bone formation around the rods. Our findings indicate that Ti-Nb-Sn alloy treated with anodic oxidation and hot water showed greater capacity for apatite formation, stronger bone bonding and higher biocompatibility for osteosynthesis. Ti-Nb-Sn alloy treated with anodic oxidation and hot water treatment is a promising material for orthopaedic implants enabling higher osteosynthesis and lower stress disproportion. PMID:26914329

  8. Modification on surface oxide layer structure and surface morphology of niobium by gas cluster ion beam treatments

    International Nuclear Information System (INIS)

    Wu, A.T.; Swenson, D.R.; Insepov, Z.

    2010-01-01

    Recently, it was demonstrated that significant reductions in field emission on Nb surfaces could be achieved by means of a new surface treatment technique called gas cluster ion beam (GCIB). Further study as shown in this paper revealed that GCIB treatments could modify surface irregularities and remove surface asperities leading to a smoother surface finish as demonstrated through measurements using a 3D profilometer, an atomic force microscope, and a scanning electron microscope. These experimental observations were supported by computer simulation via atomistic molecular dynamics and a phenomenological surface dynamics. Measurements employing a secondary ion mass spectrometry found that GCIB could also alter Nb surface oxide layer structure. Possible implications of the experimental results on the performance of Nb superconducting radio frequency cavities treated by GCIB will be discussed. First experimental results on Nb single cell superconducting radio frequency cavities treated by GCIB will be reported.

  9. Modified stainless steel for high performance and stable anode in microbial fuel cells

    International Nuclear Information System (INIS)

    Peng, Xinwen; Chen, Shuiliang; Liu, Lang; Zheng, Suqi; Li, Ming

    2016-01-01

    Graphical abstract: A high performance and stable anode was prepared for microbial fuel cells by surface modification of stainless steel mesh including steps of acid etching, binder-free carbon black (CB) coating and the low-temperature heat treatment below 400 °C. The modified anode could deliver a stable and high current density of 1.91 mA cm −2 . - Highlights: • A high-performance anode for MFC is prepared by surface modification of SSM. • The modified SSM could generate a high current density of up to 1.91 mA cm −2 . • The formation of Fe 3 O 4 layer enhanced the interaction between the CB and SSM. • The modified SSM was stable under the potential of +0.2 V (vs. Ag/AgCl). • The modified SSM was an ideal anode for upscaling applications of MFCs. - Abstract: The surface modification of the stainless steel mesh (SSM) was conducted by acid etching, binder-free carbon black (CB) coating and the low-temperature heat treatment below 400 °C to improve the microbial bioelectrocatalytic activity for use as high-performance anode in microbial fuel cells. The modified SSM, such as SSM/CB-400, could generate a high current density of up to 1.91 mA cm −2 , which was nearly three orders of magnitude higher than the untreated SSM electrode (0.0025 mA cm −2 ). Moreover, it was stable and recovered the equal current density after removal of the formed biofilms. Surface characterization results demonstrate that the performance improvement was attributed to the CB/Fe 3 O 4 composite layer formed onto the surface of the SSM, which protected the biofilms from being poisoned by the Cr component in the SSM and ensured a rapid electron transfer from biofilms to the SSM surface. The CB/Fe 3 O 4 composite layer showed excellent corrosion-resistant under the oxidizing potential of + 0.2 V (vs. Ag/AgCl). Rising the heating temperature to 500 °C, the SSM-500 and SSM/CB-500 electrodes suffered from corrosion due to the formation of α-Fe 2 O 3 crystals.

  10. Plastic deformation to enhance plasma-assisted nitriding: On surface contamination induced by Surface Mechanical Attrition Treatment

    International Nuclear Information System (INIS)

    Samih, Youssef; Novelli, Marc; Bolle, Bernard; Allain, Nathalie; Fundenberger, Jean-Jacques; Marcos, Grégory; Czerwiec, Thierry; Grosdidier, Thierry; Thiriet, Tony

    2014-01-01

    The Surface Mechanical Attrition Treatment is a recent technique leading to the formation of nanostructured layers by the repeated action of impacting balls. While several communications have revealed possible contamination of the SMATed surfaces, the nature of this surface contamination was analyzed in the present contribution for the treatment of an AISI 316L stainless steel. It is shown, by a combination of Transmission Electron Microscopy and Glow Discharge – Optical Emission Spectrometry, that the surface was alloyed with Ti, Al and V coming from the sonotrode that is used to move the balls as well as Zr coming from the zirshot® balls themselves

  11. Plastic deformation to enhance plasma-assisted nitriding: On surface contamination induced by Surface Mechanical Attrition Treatment

    Science.gov (United States)

    Samih, Youssef; Novelli, Marc; Thiriet, Tony; Bolle, Bernard; Allain, Nathalie; Fundenberger, Jean-Jacques; Marcos, Grégory; Czerwiec, Thierry; Grosdidier, Thierry

    2014-08-01

    The Surface Mechanical Attrition Treatment is a recent technique leading to the formation of nanostructured layers by the repeated action of impacting balls. While several communications have revealed possible contamination of the SMATed surfaces, the nature of this surface contamination was analyzed in the present contribution for the treatment of an AISI 316L stainless steel. It is shown, by a combination of Transmission Electron Microscopy and Glow Discharge - Optical Emission Spectrometry, that the surface was alloyed with Ti, Al and V coming from the sonotrode that is used to move the balls as well as Zr coming from the zirshot® balls themselves.

  12. Dielectric breakdown and healing of anodic oxide films on aluminium under single pulse anodizing

    International Nuclear Information System (INIS)

    Sah, Santosh Prasad; Tatsuno, Yasuhiro; Aoki, Yoshitaka; Habazaki, Hiroki

    2011-01-01

    Research highlights: → We examined dielectric breakdown of anodic alumina by single pulse anodizing. → Current transients and morphology of discharge channels are dependent upon electrolyte and voltage. → There is a good correlation between current transient and morphology of discharge channel. → Healing of open discharge pores occurs in alkaline silicate, but not in pentaborate electrolyte. - Abstract: Single pulse anodizing of aluminium micro-electrode has been employed to study the behaviour of dielectric breakdown and subsequent oxide formation on aluminium in alkaline silicate and pentaborate electrolytes. Current transients during applying pulse voltage have been measured, and surface has been observed by scanning electron microscopy. Two types of current transients are observed, depending on the electrolyte and applied voltage. There is a good correlation between the current transient behaviour and the shape of discharge channels. In alkaline silicate electrolyte, circular open pores are healed by increasing the pulse width, but such healing is not obvious in pentaborate electrolyte.

  13. Analytical modelling for ultrasonic surface mechanical attrition treatment

    Directory of Open Access Journals (Sweden)

    Guan-Rong Huang

    2015-07-01

    Full Text Available The grain refinement, gradient structure, fatigue limit, hardness, and tensile strength of metallic materials can be effectively enhanced by ultrasonic surface mechanical attrition treatment (SMAT, however, never before has SMAT been treated with rigorous analytical modelling such as the connection among the input energy and power and resultant temperature of metallic materials subjected to SMAT. Therefore, a systematic SMAT model is actually needed. In this article, we have calculated the averaged speed, duration time of a cycle, kinetic energy and kinetic energy loss of flying balls in SMAT for structural metallic materials. The connection among the quantities such as the frequency and amplitude of attrition ultrasonic vibration motor, the diameter, mass and density of balls, the sample mass, and the height of chamber have been considered and modelled in details. And we have introduced the one-dimensional heat equation with heat source within uniform-distributed depth in estimating the temperature distribution and heat energy of sample. In this approach, there exists a condition for the frequency of flying balls reaching a steady speed. With these known quantities, we can estimate the strain rate, hardness, and grain size of sample.

  14. Bioactive carbon-PEEK composites prepared by chemical surface treatment.

    Science.gov (United States)

    Miyazaki, Toshiki; Matsunami, Chisato; Shirosaki, Yuki

    2017-01-01

    Polyetheretherketone (PEEK) has attracted much attention as an artificial intervertebral spacer for spinal reconstruction. Furthermore, PEEK plastic reinforced with carbon fiber has twice the bending strength of pure PEEK. However, the PEEK-based materials do not show ability for direct bone bonding, i.e., bioactivity. Although several trials have been conducted for enabling PEEK with bioactivity, few studies have reported on bioactive surface modification of carbon-PEEK composites. In the present study, we attempted the preparation of bioactive carbon-PEEK composites by chemical treatments with H 2 SO 4 and CaCl 2 . Bioactivity was evaluated by in vitro apatite formation in simulated body fluid (SBF). The apatite formation on the carbon-PEEK composite was compared with that of pure PEEK. Both pure PEEK and carbon-PEEK composite formed the apatite in SBF when they were treated with H 2 SO 4 and CaCl 2 ; the latter showed higher apatite-forming ability than the former. It is conjectured that many functional groups able to induce the apatite nucleation, such as sulfo and carboxyl groups, are incorporated into the dispersed carbon phase in the carbon-PEEK composites. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. A Study on the Anodic Dissolution of Aluminum(II)

    International Nuclear Information System (INIS)

    Nam, C. W.; Park, C. S.; Park, C. S.

    1978-01-01

    In many cases oxide films formed on metals in atmosphere or aqueous solution are chemically inactive, especially it is the case with aluminum. In this study, anodic dissolution of aluminum was done using various electrolyte and cathode, mechanism of which was examined. As a consequence, oxide film on aluminum surface was dissolved together with the dissolution reaction of metal by the anodic current. It was shown that the dissolution reaction due to the contact between electrolyte and metal happened in the same time

  16. Improved adhesion of Ag NPs to the polyethylene terephthalate surface via atmospheric plasma treatment and surface functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Tao [Faculty of Materials Science and Engineering, Kunming University of Science and Technology, 253 Xuefu Rd, Kunming, Yunnan, 650093 (China); Liu, Yong [Faculty of Materials Science and Engineering, Kunming University of Science and Technology, 253 Xuefu Rd, Kunming, Yunnan, 650093 (China); Solmont Technology Wuxi Co., Ltd. 228 Linghu Blvd. Tianan Tech Park, A1-602, Xinwu District, Wuxi, Jiangsu 214135 (China); Zhu, Yan, E-mail: zhuyan@kmust.edu.cn [Faculty of Materials Science and Engineering, Kunming University of Science and Technology, 253 Xuefu Rd, Kunming, Yunnan, 650093 (China); Yang, De-Quan, E-mail: dequan.yang@gmail.com [Faculty of Materials Science and Engineering, Kunming University of Science and Technology, 253 Xuefu Rd, Kunming, Yunnan, 650093 (China); Solmont Technology Wuxi Co., Ltd. 228 Linghu Blvd. Tianan Tech Park, A1-602, Xinwu District, Wuxi, Jiangsu 214135 (China); Sacher, Edward [Regroupement Québécois de Matériaux de Pointe, Department of Engineering Physics, École Polytechnique de Montréal, Case Postale 6079, succursale Centre-Ville, Montréal, Québec H3C 3A7 (Canada)

    2017-07-31

    Highlights: • A two-step process has been developed to enhance the adhesion of immobilized Ag NPs to the PET surface. • The method is simple, easy to use and low-cost for mass production. • The increased density of active sites (−OH, −CH=O and COOH) at the PET surface, after plasma treatment, permits increased reaction with 3-aminopropyltriethoxysilane (APTES). • The presence of APTES with high surface density permits −NH{sub 2}-Ag complex formation, increasing the adhesion of the Ag NPs. - Abstract: Ag nanoparticles (NPs) have been widely applied, as important antibacterial materials, on textile and polymer surfaces. However, their adhesion to nonreactive polymer surfaces is generally too weak for many applications. Here, we propose a two-step process, atmospheric plasma treatment followed by a surface chemical modification process, which enhances their adhesion to polyethylene terephthalate (PET) surfaces. We found that, compared to either plasma treatments or surface chemical functionalizations, alone, this combination greatly enhanced their adhesion. The plasma treatment resulted in an increase of active sites (−OH, −CH=O and COOH) at the PET surface, permitting increased bonding to 3-aminopropyltriethoxysilane (APTES), whose −NH{sub 2} groups were then able to form a bonding complex with the Ag NPs.

  17. Status of surface treatment in endosseous implant: A literary overview

    Directory of Open Access Journals (Sweden)

    Gupta Ankur

    2010-01-01

    Full Text Available The attachment of cells to titanium surfaces is an important phenomenon in the area of clinical implant dentistry. A major consideration in designing implants has been to produce surfaces that promote desirable responses in the cells and tissues. To achieve these requirements, the titanium implant surface can be modified in various ways. This review mainly focuses on the surface topography of dental implants currently in use, emphasizing the association of reported variables with biological outcome.

  18. [Observation of topography and analysis of surface contamination of titanium implant after roughness treatment].

    Science.gov (United States)

    Cao, Hongdan; Yang, Xiaodong; Wu, Dayi; Zhang, Xingdong

    2007-04-01

    The roughness treatment of dental implant surface could improve the bone bonding and increase the success rate of implant, but the difference of diverse treatments is still unknown. In this study using scanning electron microscopy (SEM), energy disperse spectrometer (EDS) and the test of contact angle, we studied the microstructure, surface contamination and surface energy, and hence conducted a comparative analysis of the following surface roughness treatments: Polished Treatment (PT), Sandblasting with Alumina(SA), Sandblasting with Aluminia and Acid-etched (SAA), Sandblasting with Titanium Acid-etched (STA), Electro-erosion Treatment(ET). The result of SEM showed that the surface displayed irregularities after roughness treatments and that the surface properties of different roughness treatments had some distinctions. SAA and SA had some sharp edges and protrutions; the STA showed a regular pattern like honeycomb, but the ET sample treated by electric erosion exhibited the deeper pores of different sizes and the pores with a perforated secondary structure. The EDS indicated that the surface was contaminated after the treatment with foreign materials; the SA surface had some embedded contaminations even after acid etching. The measurement of water contact angle indicated that the morphology correlated with the surface treatments. These findings suggest that the distinction of surface structure and composition caused by different treatments may result in the disparity in biological behavior of dental implant.

  19. FIB-SEM investigation of trapped intermetallic particles in anodic oxide films on AA1050 aluminium

    DEFF Research Database (Denmark)

    Jariyaboon, Manthana; Møller, Per; Dunin-Borkowski, Rafal E.

    2011-01-01

    -containing intermetallic particles incorporated into the anodic oxide films on industrially pure aluminium (AA1050, 99.5 per cent) has been investigated. AA1050 aluminium was anodized in a 100?ml/l sulphuric acid bath with an applied voltage of 14?V at 20°C ±2°C for 10 or 120?min. The anodic film subsequently was analyzed......Purpose - The purpose of this investigation is to understand the structure of trapped intermetallics particles and localized composition changes in the anodized anodic oxide film on AA1050 aluminium substrates. Design/methodology/approach - The morphology and composition of Fe......-shaped particles were embedded in the anodic oxide film as a thin strip structure and located near the top surface of the film, whereas the round-shaped particles were trapped in the film with a spherical structure, but partially dissolved and were located throughout the thickness of the anodic film. The Fe...

  20. Comparative use of anodic oxidation, electro-Fenton and photoelectro-Fenton with Pt or boron-doped diamond anode to decolorize and mineralize Malachite Green oxalate dye

    International Nuclear Information System (INIS)

    El-Ghenymy, Abdellatif; Centellas, Francesc; Rodríguez, Rosa María; Cabot, Pere Lluís; Garrido, José Antonio; Sirés, Ignasi; Brillas, Enric

    2015-01-01

    Highlights: • Degradation of Malachite Green oxalate solutions at pH 3.0 by AO, AO-H 2 O 2 , EF and PEF. • A Pt anode leads to slower decolorization and mineralization than BDD. • Up to 97% mineralization by the most powerful PEF process with BDD at 100 mA cm −2 . • Study of the evolution of seven final short-chain aliphatic carboxylic acids. • Conversion of the initial N atoms of the dye mainly into NH 4 + , along with small amounts of NO 3 − . - Abstract: The degradation of 100 cm 3 of 177 mg dm −3 of the triphenylmethane dye Malachite Green oxalate at pH 3.0 was studied by anodic oxidation with stainless steel cathode (AO-SS), AO with air-diffusion cathode (AO-H 2 O 2 ), electro-Fenton (EF) and photoelectro-Fenton (PEF) with UVA light. The main oxidizing species were hydroxyl radicals formed from either water oxidation at the anode surface or in the bulk between added Fe 2+ and H 2 O 2 generated at the air-diffusion cathode. The use of a Pt anode led to slower decolorization and mineralization than BDD in all treatments because of the higher oxidation power of the latter. The decolorization was much faster for EF and PEF compared to AO-SS and AO-H 2 O 2 due to the contribution of hydroxyl radicals in the bulk. PEF allowed the quickest color removal by the rapid Fe 2+ regeneration from the photolysis of Fe(III) complexes with oxalate. The most powerful process was PEF with BDD, which yielded total decolorization in 6 min and 97% mineralization at 240 min operating at 100 mA cm −2 , thanks to hydroxyl radicals formed at the anode surface and in the bulk along with the photolytic action of UVA radiation. The evolution of final carboxylic acids like maleic, fumaric, succinic, acetic, oxalic, formic and oxamic was followed by ion-exclusion HPLC. All these acids and their Fe(III) complexes were removed more slowly with Pt anode. The initial N atoms of the dye were pre-eminently accumulated as NH 4 + ion, along with small amounts of NO 3 − ion.

  1. Process for anodizing aluminum foil

    International Nuclear Information System (INIS)

    Ball, J.A.; Scott, J.W.

    1984-01-01

    In an integrated process for the anodization of aluminum foil for electrolytic capacitors including the formation of a hydrous oxide layer on the foil prior to anodization and stabilization of the foil in alkaline borax baths during anodization, the foil is electrochemically anodized in an aqueous solution of boric acid and 2 to 50 ppm phosphate having a pH of 4.0 to 6.0. The anodization is interrupted for stabilization by passing the foil through a bath containing the borax solution having a pH of 8.5 to 9.5 and a temperature above 80 0 C. and then reanodizing the foil. The process is useful in anodizing foil to a voltage of up to 760 V

  2. The characteristics of anodic coating of Al-alloy claddings

    International Nuclear Information System (INIS)

    Yang Yong; Zou Benhui; Guo Hong; Du Yanhua; Bai Zhiyong; Cai Zhenfang

    2014-01-01

    Aluminum alloy claddings of research reactor fuel elements should be corroded by sodium hydroxide solution and anodized in sulfuric acid solution, but there are often some uneven color phenomena on surfaces, and sometimes regions of 'black and white stripes' appear. In order to study the relationship of colorful stripes on coatings and the surface morphology of aluminum alloy claddings corroded by sodium hydroxide solution, surface microstructures and second phase particles of the aluminum alloy claddings, which were corroded by sodium hydroxide solution, are investigated metallographically and via SEM analysis; Meanwhile, thickness, microstructure, chemical composition and construction of anodic oxidation coatings on aluminum coatings are analyzed. It is shown that: 1) the darker the surface color of corroded aluminum alloy claddings is, the darker of anodic oxidation coating; 2) there are many micro-pores on anodized oxidation coatings, which is much similar to that of corroded aluminum alloy claddings according to the morphology and distribution. So, it can be deduced that the surface morphology of anodic coatings is inherited from the corroded surfaces. (authors)

  3. Nanostructured Si/TiC composite anode for Li-ion batteries

    International Nuclear Information System (INIS)

    Zeng, Z.Y.; Tu, J.P.; Yang, Y.Z.; Xiang, J.Y.; Huang, X.H.; Mao, F.; Ma, M.

    2008-01-01

    Si/TiC nanocomposite anode was synthesized by a surface sol-gel method in combination with a following heat-treatment process. Through this process, nanosized Si was homogeneously distributed in a titanium carbide matrix. The electrochemically less active TiC working as a buffer matrix successfully prevented Si from cracking/crumbling during the charging/discharging process. The interspaces in the Si/TiC nanocomposite could offer convenient channels for Li ions to react with active Si. The Si/TiC composite exhibited a reversible charge/discharge capacity of about 1000 mAh g -1 with average discharge capacity fading of 1.8 mAh g -1 (0.18%) from 2nd to 100th cycle, indicating its excellent cyclability when used as anode materials for lithium-ion batteries

  4. Improvement of silicon direct bonding using surfaces activated by hydrogen plasma treatment

    CERN Document Server

    Choi, W B; Lee Jae Sik; Sung, M Y

    2000-01-01

    The plasma surface treatment, using hydrogen gas, of silicon wafers was studied as a pretreatment for silicon direct bonding. Chemical reactions of the hydrogen plasma with the surfaces were used for both surface activation and removal of surface contaminants. Exposure of the silicon wafers to the plasma formed an active oxide layer on the surface. This layer was hydrophilic. The surface roughness and morphology were examined as functions of the plasma exposure time and power. The surface became smoother with shorter plasma exposure time and lower power. In addition, the plasma surface treatment was very efficient in removing the carbon contaminants on the silicon surface. The value of the initial surface energy, as estimated by using the crack propagation method, was 506 mJ/M sup 2 , which was up to about three times higher than the value for the conventional direct bonding method using wet chemical treatments.

  5. Anode sheath in Hall thrusters

    International Nuclear Information System (INIS)

    Dorf, L.; Semenov, V.; Raitses, Y.

    2003-01-01

    A set of hydrodynamic equations is used to describe quasineutral plasma in ionization and acceleration regions of a Hall thruster. The electron distribution function and Poisson equation are invoked for description of a near-anode region. Numerical solutions suggest that steady-state operation of a Hall thruster can be achieved at different anode sheath regimes. It is shown that the anode sheath depends on the thruster operating conditions, namely the discharge voltage and the mass flow rate

  6. High-capacity nanocarbon anodes for lithium-ion batteries

    International Nuclear Information System (INIS)

    Zhang, Haitao; Sun, Xianzhong; Zhang, Xiong; Lin, He; Wang, Kai; Ma, Yanwei

    2015-01-01

    Highlights: • The nanocarbon anodes in lithium-ion batteries deliver a high capacity of ∼1100 mA h g −1 . • The nanocarbon anodes exhibit excellent cyclic stability. • A novel structure of carbon materials, hollow carbon nanoboxes, has potential application in lithium-ion batteries. - Abstract: High energy and power density of secondary cells like lithium-ion batteries become much more important in today’s society. However, lithium-ion battery anodes based on graphite material have theoretical capacity of 372 mA h g −1 and low charging-discharging rate. Here, we report that nanocarbons including mesoporous graphene (MPG), carbon tubular nanostructures (CTN), and hollow carbon nanoboxes (HCB) are good candidate for lithium-ion battery anodes. The nanocarbon anodes have high capacity of ∼1100, ∼600, and ∼500 mA h g −1 at 0.1 A g −1 for MPG, CTN, and HCB, respectively. The capacity of 181, 141, and 139 mA h g −1 at 4 A g −1 for MPG, CTN, and HCB anodes is retained. Besides, nanocarbon anodes show high cycling stability during 1000 cycles, indicating formation of a passivating layer—solid electrolyte interphase, which support long-term cycling. Nanocarbons, constructed with graphene layers which fulfill lithiation/delithiation process, high ratio of graphite edge structure, and high surface area which facilitates capacitive behavior, deliver high capacity and improved rate-capability

  7. Atmospheric pressure arc discharge with ablating graphite anode

    International Nuclear Information System (INIS)

    Nemchinsky, V A; Raitses, Y

    2015-01-01

    The anodic carbon arc discharge is used to produce carbon nanoparticles. Recent experiments with the carbon arc at atmospheric pressure helium demonstrated the enhanced ablation rate for narrow graphite anodes resulting in high deposition rates of carbonaceous products on the copper cathode (Fetterman et al 2008 Carbon 46 1322–6). The proposed model explains these results with interconnected steady-state models of the cathode and the anode processes. When considering cathode functioning, the model predicts circulation of the particles in the near-cathode region: evaporation of the cathode material, ionization of evaporated atoms and molecules in the near-cathode plasma, return of the resulting ions to the cathode, surface recombination of ions and electrons followed again by cathode evaporation etc. In the case of the low anode ablation rate, the ion acceleration in the cathode sheath provides the major cathode heating mechanism. In the case of an intensive anode ablation, an additional cathode heating is due to latent fusion heat of the atomic species evaporated from the anode and depositing at the cathode. Using the experimental arc voltage as the only input discharge parameter, the model allows us to calculate the anode ablation rate. A comparison of the results of calculations with the available experimental data shows reasonable agreement. (paper)

  8. Atmospheric pressure arc discharge with ablating graphite anode

    Science.gov (United States)

    Nemchinsky, V. A.; Raitses, Y.

    2015-06-01

    The anodic carbon arc discharge is used to produce carbon nanoparticles. Recent experiments with the carbon arc at atmospheric pressure helium demonstrated the enhanced ablation rate for narrow graphite anodes resulting in high deposition rates of carbonaceous products on the copper cathode (Fetterman et al 2008 Carbon 46 1322-6). The proposed model explains these results with interconnected steady-state models of the cathode and the anode processes. When considering cathode functioning, the model predicts circulation of the particles in the near-cathode region: evaporation of the cathode material, ionization of evaporated atoms and molecules in the near-cathode plasma, return of the resulting ions to the cathode, surface recombination of ions and electrons followed again by cathode evaporation etc. In the case of the low anode ablation rate, the ion acceleration in the cathode sheath provides the major cathode heating mechanism. In the case of an intensive anode ablation, an additional cathode heating is due to latent fusion heat of the atomic species evaporated from the anode and depositing at the cathode. Using the experimental arc voltage as the only input discharge parameter, the model allows us to calculate the anode ablation rate. A comparison of the results of calculations with the available experimental data shows reasonable agreement.

  9. Heat treatment effect on crystal structure and design of highly sensitive room temperature CO2 gas sensors using anodic Bi2O3 nanoporous formed in a citric acid electrolyte

    Science.gov (United States)

    Ahila, M.; Dhanalakshmi, J.; Celina Selvakumari, J.; Pathinettam Padiyan, D.

    2016-10-01

    The effect of annealing temperature on the crystal structure of anodic bismuth trioxide (ABO) layers prepared via anodization in a citric acid-based electrolyte was studied. The samples were annealed in air at temperatures ranging from 200 °C to 600 °C. Characterization of nanoporous ABO layers was carried out through x-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), UV-visible (UV-Vis) diffuse reflectance spectroscopy and photoluminescence (PL). Effects of heat treatment on crystallinity, morphology and gas-sensing properties were investigated in detail. The XRD measurements showed that a gradual phase change from beta to gamma occurs with an increase in annealing temperature. The beta to gamma transformation occurred between 500 and 600 °C. The changes in the average crystallite sizes of beta and gamma occurring during heat treatment of the ABO layers are correlated with the mechanism of gamma-phase nucleation. During the growth of the gamma phase, the grain size gets enlarged with a reduction in the total area of grain boundary. The pores’ formation and the pore diameter of both anodized and annealed samples were found to be in the range of 50 to 150 nm. The band gap of the ABO layer crystallines was determined using the diffuse reflectance technique according to the Kubelka-Munk theory. Results showed that the band gap of the ABO layer decreased from 4.09 to 2.42 eV when the particle size decreased from 58 to 24 nm. The CO2 sensing properties of the ABO were investigated at room temperature for 0-100 ppm concentration. The variations in the electrical resistances were measured with the exposure of CO2 as a function of time. The maximum value of the response magnitude of 77% was obtained for 100 ppm of CO2. These experimental results show that the ABO layer of nanoporous is a promising material for CO2 sensors at room temperature.

  10. Blue fluorescent organic light emitting diodes with multilayered graphene anode

    International Nuclear Information System (INIS)

    Hwang, Joohyun; Choi, Hong Kyw; Moon, Jaehyun; Shin, Jin-Wook; Joo, Chul Woong; Han, Jun-Han; Cho, Doo-Hee; Huh, Jin Woo; Choi, Sung-Yool; Lee, Jeong-Ik; Chu, Hye Yong

    2012-01-01

    As an innovative anode for organic light emitting devices (OLEDs), we have investigated graphene films. Graphene has importance due to its huge potential in flexible OLED applications. In this work, graphene films have been catalytically grown and transferred to the glass substrate for OLED fabrications. We have successfully fabricated 2 mm × 2 mm device area blue fluorescent OLEDs with graphene anodes which showed 2.1% of external quantum efficiency at 1000 cd/m 2 . This is the highest value reported among fluorescent OLEDs using graphene anodes. Oxygen plasma treatment on graphene has been found to improve hole injections in low voltage regime, which has been interpreted as oxygen plasma induced work function modification. However, plasma treatment also increases the sheet resistance of graphene, limiting the maximum luminance. In summary, our works demonstrate the practical possibility of graphene as an anode material for OLEDs and suggest a processing route which can be applied to various graphene related devices.

  11. Improvement of chronic corneal opacity in ocular surface disease with prosthetic replacement of the ocular surface ecosystem (PROSE) treatment.

    Science.gov (United States)

    Cressey, Anna; Jacobs, Deborah S; Remington, Crystal; Carrasquillo, Karen G

    2018-06-01

    To demonstrate clearing of chronic corneal opacities and improvement of visual acuity with the use of BostonSight prosthetic replacement of the ocular surface ecosystem (PROSE) treatment in ocular surface disease. We undertook retrospective analysis of the medical records of a series of patients who underwent PROSE treatment from August 2006 to December 2014. Patients were referred for ocular surface disease of various etiologies. Primary inclusion criterion was corneal opacity that improved with PROSE treatment. Patients were excluded if topical steroids or adjuvant therapy used once PROSE treatment was initiated. Underlying disease, prior treatment, clinical presentation, and clinical course were extracted from the medical record. Four patients are included in this series. There were three females and one male; median age at time of treatment initiation was 30 years (range = 0.5-58 years). Median duration of PROSE treatment at time of retrospective analysis was 3.5 years (range = 1-8 years). Two cases had corneal opacification in the context of neurotrophic keratopathy: a unilateral case due to presumed herpes simplex keratitis and a bilateral case due to congenital corneal anesthesia associated with familial dysautonomia. One case had corneal opacity from exposure related to seventh nerve palsy, and one had corneal opacification associated with recurrent surface breakdown, neurotrophic keratopathy, and limbal stem deficiency of uncertain etiology. After consistent wear of prosthetic devices used in PROSE treatment for support of the ocular surface, visual acuity improved and clearing of the opacities was observed, without use of topical steroids or adjuvant therapy. These cases demonstrate clearing of chronic corneal opacity with PROSE treatment for ocular surface disease. This clearing can occur with no adjuvant therapy, suggesting that restoration of ocular surface function and integrity allows for corneal remodeling.

  12. Effect of heat treatment on surface hydrophilicity-retaining ability of titanium dioxide nanotubes

    Science.gov (United States)

    Sun, Yu; Sun, Shupei; Liao, Xiaoming; Wen, Jiang; Yin, Guangfu; Pu, Ximing; Yao, Yadong; Huang, Zhongbing

    2018-05-01

    The aim of this study is to investigate the effect of different annealing temperature and atmosphere on the surface wettability retaining properties of titania nanotubes (TNs) fabricated by anodization. The TNs morphology, crystal phase composition and surface elemental composition and water contact angle (WCA) were investigated by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and contact angle instrument, respectively. After the samples annealed at 200 °C, 450 °C, 850 °C have been stored in air for 28 days, the WCAs increase to 31.7°, 21.1° and 110.5°, respectively. The results indicate that crystal phase composition of TNs plays an important role in surface wettability. Compared with the WCA (21.1°) of the samples annealed in air after 28 days, the WCA of samples annealed in oxygen-deficient atmosphere is lower, suggesting the contribution of oxygen vacancy in the enhanced hydrophilicity-retaining ability. Our study demonstrates that the surface hydrophilicity-retaining ability of TNs is related to the ordered nanotubular structure, crystal structure, the amount of surface hydroxyl group and oxygen vacancy defects.

  13. Surface Treatment of Polymeric Materials Controlling the Adhesion of Biomolecules

    Directory of Open Access Journals (Sweden)

    Willy Zorzi

    2012-08-01

    Full Text Available This review describes different strategies of surface elaboration for a better control of biomolecule adsorption. After a brief description of the fundamental interactions between surfaces and biomolecules, various routes of surface elaboration are presented dealing with the attachment of functional groups mostly thanks to plasma techniques, with the grafting to and from methods, and with the adsorption of surfactants. The grafting of stimuli-responsive polymers is also pointed out. Then, the discussion is focused on the protein adsorption phenomena showing how their interactions with solid surfaces are complex. The adsorption mechanism is proved to be dependent on the solid surface physicochemical properties as well as on the surface and conformation properties of the proteins. Different behaviors are also reported for complex multiple protein solutions.

  14. Surface Treatment of Polymeric Materials Controlling the Adhesion of Biomolecules

    Science.gov (United States)

    Poncin-Epaillard, Fabienne; Vrlinic, Tjasa; Debarnot, Dominique; Mozetic, Miran; Coudreuse, Arnaud; Legeay, Gilbert; El Moualij, Benaïssa; Zorzi, Willy

    2012-01-01

    This review describes different strategies of surface elaboration for a better control of biomolecule adsorption. After a brief description of the fundamental interactions between surfaces and biomolecules, various routes of surface elaboration are presented dealing with the attachment of functional groups mostly thanks to plasma techniques, with the grafting to and from methods, and with the adsorption of surfactants. The grafting of stimuli-responsive polymers is also pointed out. Then, the discussion is focused on the protein adsorption phenomena showing how their interactions with solid surfaces are complex. The adsorption mechanism is proved to be dependent on the solid surface physicochemical properties as well as on the surface and conformation properties of the proteins. Different behaviors are also reported for complex multiple protein solutions. PMID:24955631

  15. Anode modification with formic acid: A simple and effective method to improve the power generation of microbial fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Weifeng; Cheng, Shaoan, E-mail: shaoancheng@zju.edu.cn; Guo, Jian

    2014-11-30

    Highlights: • Carbon cloth anode is modified with formic acid by a simple and reliable approach. • The modification significantly enhances the power output of microbial fuel cells. • The modified anode surface favors the bacterial attachment and growth on anode. • The electron transfer rate of anode is promoted. - Abstract: The physicochemical properties of anode material directly affect the anodic biofilm formation and electron transfer, thus are critical for the power generation of microbial fuel cells (MFCs). In this work, carbon cloth anode was modified with formic acid to enhance the power production of MFCs. Formic acid modification of anode increased the maximum power density of a single-chamber air-cathode MFC by 38.1% (from 611.5 ± 6 mW/m{sup 2} to 877.9 ± 5 mW/m{sup 2}). The modification generated a cleaner electrode surface and a reduced content of oxygen and nitrogen groups on the anode. The surface changes facilitated bacterial growth on the anode and resulted in an optimized microbial community. Thus, the electron transfer rate on the modified anodes was enhanced remarkably, contributing to a higher power output of MFCs. Anode modification with formic acid could be an effective and simple method for improving the power generation of MFCs. The modification method holds a huge potential for large scale applications and is valuable for the scale-up and commercialization of microbial fuel cells.

  16. Apparatus and process for the surface treatment of carbon fibers

    Science.gov (United States)

    Paulauskas, Felix Leonard; Ozcan, Soydan; Naskar, Amit K.

    2016-05-17

    A method for surface treating a carbon-containing material in which carbon-containing material is reacted with decomposing ozone in a reactor (e.g., a hollow tube reactor), wherein a concentration of ozone is maintained throughout the reactor by appropriate selection of at least processing temperature, gas stream flow rate, reactor dimensions, ozone concentration entering the reactor, and position of one or more ozone inlets (ports) in the reactor, wherein the method produces a surface-oxidized carbon or carbon-containing material, preferably having a surface atomic oxygen content of at least 15%. The resulting surface-oxidized carbon material and solid composites made therefrom are also described.

  17. Effects of Charcoal Addition on the Properties of Carbon Anodes

    Directory of Open Access Journals (Sweden)

    Asem Hussein

    2017-03-01

    Full Text Available Wood charcoal is an attractive alternative to petroleum coke in production of carbon anodes for the aluminum smelting process. Calcined petroleum coke is the major component in the anode recipe and its consumption results in a direct greenhouse gas (GHG footprint for the industry. Charcoal, on the other hand, is considered as a green and abundant source of sulfur-free carbon. However, its amorphous carbon structure and high contents of alkali and alkaline earth metals (e.g., Na and Ca make charcoal highly reactive to air and CO2. Acid washing and heat treatment were employed in order to reduce the reactivity of charcoal. The pre-treated charcoal was used to substitute up to 10% of coke in the anode recipe in an attempt to investigate the effect of this substitution on final anode properties. The results showed deterioration in the anode properties by increasing the charcoal content. However, by adjusting the anode recipe, this negative effect can be considerably mitigated. Increasing the pitch content was found to be helpful to improve the physical properties of the anodes containing charcoal.

  18. Effect of flattened surface morphology of anodized aluminum oxide templates on the magnetic properties of nanoporous Co/Pt and Co/Pd thin multilayered films

    Science.gov (United States)

    Nguyen, T. N. Anh; Fedotova, J.; Kasiuk, J.; Bayev, V.; Kupreeva, O.; Lazarouk, S.; Manh, D. H.; Vu, D. L.; Chung, S.; Åkerman, J.; Altynov, V.; Maximenko, A.

    2018-01-01

    For the first time, nanoporous Al2O3 templates with smoothed surface relief characterized by flattened interpore areas were used in the fabrication of Co/Pd and Co/Pt multilayers (MLs) with strong perpendicular magnetic anisotropy (PMA). Alternating gradient magnetometry (AGM) revealed perfectly conserved PMA in the Co/Pd and Co/Pt porous MLs (antidot arrays) with a ratio of remanent magnetization (Mr) to saturation magnetization (MS) of about 0.99, anisotropy fields (Ha) of up to 2.6 kOe, and a small deviation angle of 8° between the easy magnetization axis and the normal to the film surface. The sufficient magnetic hardening of the porous MLs with enhanced coercive field HC of up to ∼1.9 kOe for Co/Pd and ∼1.5 kOe for Co/Pt MLs, as compared to the continuous reference samples (∼1.5-2 times), is associated with the pinning of the magnetic moments on the nanopore edges. Application of the Stoner-Wohlfarth model for fitting the experimental M/MS(H) curves yielded clear evidence of the predominantly coherent rotation mechanism of magnetization reversal in the porous films.

  19. Influence of the anodizing process variables on the acidic properties of anodic alumina films

    Directory of Open Access Journals (Sweden)

    D.E. Boldrini

    Full Text Available Abstract In the present work, the effect of the different variables involved in the process of aluminum anodizing on the total surface acidity of the samples obtained was studied. Aluminum foils were treated by the electro-chemical process of anodic anodizing