WorldWideScience

Sample records for titanium oxide ceramic

  1. Process for making a titanium diboride-chromium diboride-yttrium titanium oxide ceramic composition

    Science.gov (United States)

    Holcombe, C.E.; Dykes, N.L.

    1992-04-28

    A ceramic composition is described. The ceramic composition consists essentially of from about 84 to 96 w/o titanium diboride, from about 1 to 9 w/o chromium diboride, and from about 3 to about 15 w/o yttrium-titanium-oxide. A method of making the ceramic composition is also described. The method of making the ceramic composition comprises the following steps: Step 1--A consolidated body containing stoichiometric quantities of titanium diboride and chromium diboride is provided. Step 2--The consolidated body is enclosed in and in contact with a thermally insulated package of yttria granules having a thickness of at least 0.5 inches. Step 3--The consolidated body enclosed in the thermally insulated package of yttria granules is heated in a microwave oven with microwave energy to a temperature equal to or greater than 1,900 degrees centigrade to sinter and uniformly disperse yttria particles having a size range from about 1 to about 12 microns throughout the consolidated body forming a densified body consisting essentially of titanium diboride, chromium diboride, and yttrium-titanium-oxide. The resulting densified body has enhanced fracture toughness and hardness. No Drawings

  2. Characterization of ceramics of titanium oxide to treatment of effluents from nuclear area

    International Nuclear Information System (INIS)

    Silva, Milena Hudson da; Oliveira, Elizabeth E. de Mello

    2017-01-01

    Membrane separation processes (PSM) have become increasingly important technology, with application in several areas to separate, concentrate or purify solutions. PSM has been justified because it is an easy-to-operate separation technique and, in general, does not involve phase change. Ceramic membranes exhibit superior properties as polymeric, mainly about chemical resistance to solvents and extremes of temperature and pH. Ceramic membranes are composed of a porous support, responsible for the mechanical resistance and covered by a thin layer, responsible for selectivity. In this work were prepared supports based on titanium oxide (TiO 2 ), which features high stability, thermal, chemical resistance to organic solvents and application in a wide pH range (0-14). Three aqueous solutions were prepared containing TiO 2 and corn starch at concentrations of 0, 15 and 30%, acting as a pores former. The solutions were dried in Spray-Dryer, to obtain a homogeneous mixture and grainy. The support has been compressed to a pressure of 1.5 Kgfcm -2 in the form of cylindrical disks of 2.5 cm diameter sintered at temperatures of 1100 and and 1150° C. The discs were weighed and their dimensions measured for the determination of geometric density and porosity. Hydraulic permeability tests were performed at pressures of 1 to 4 bar. The conditions of 1100 ° C without addition of starch and 1150 ° C with 15% of starch had porosities of 42% and 44%, respectively, values close to that suggested in the literature, between 35-40%

  3. Oxide ceramics

    International Nuclear Information System (INIS)

    Ryshkewitch, E.; Richerson, D.W.

    1985-01-01

    The book explores single-phase ceramic oxide systems from the standpoint of physical chemistry and technology. This second edition also focuses on advances in technology since publication of the original edition. These include improvements in raw materials and forming and sintering techniques, and the major role that oxide ceramics have had in development of advanced products and processes. The text is divided into five major sections: general fundamentals of oxide ceramics, advances in aluminum oxide technology, advances in zirconia technology, and advances in beryllium oxide technology

  4. Use of aluminum oxides, titanium and cerium in the production of ceramic composites for protective coating of storage tanks and transportation of oil raw

    International Nuclear Information System (INIS)

    Rego, S.A.B.C.; Ferreira, R.A.S.; Yadava, Y.P.

    2012-01-01

    The deployment of the Abreu e Lima refinery in the port of SUAPE - PE will increase the need to store oil in the region, it is essential to research and develop new materials inert to chemical attack promoted by oil. In this work, we produce the ceramic composite alumina-titania, ceria of high mechanical strength which is observed that with additions of titanium oxide in the order of 15% and 20% better results are obtained as possibly indicating these composites suitable for use in coating ceramic storage tanks of crude oil. (author)

  5. Titanium oxide fever

    International Nuclear Information System (INIS)

    De Jonge, D.; Visser, J.

    2012-01-01

    One measure to improve air quality is to apply photo-catalytic substances that capture NOx onto the road surface or onto baffle boards alongside the roads. The effect of titanium oxide containing clinkers with coating was discussed in the report 'Demonstration project of air-purifying pavement in Hengelo, The Netherlands' that was published in May 2011. This article examines the way in which the effectiveness of this study was determined. Can titanium oxide containing clinkers and coatings indeed capture NOx?. [nl

  6. Mechanochemistry of titanium oxides

    Directory of Open Access Journals (Sweden)

    Veljković Ivana

    2009-01-01

    Full Text Available Mechanochemistry represents an alternative route in synthesis of nanomaterials. Mechanochemical routes are attractive because of their simplicity, flexibility, and ability to prepare materials by solid state reactions at room temperature. The aim of this work is the mechanochemical synthesis of nanostructured titanium oxides of different composition starting from mixtures of Ti and TiO2, TiO and TiO2 or Ti2O3 and TiO2. Emphasis is on the Magneli phases Ti4O7 and Ti5O9 because their mixture is commercially known as EBONEX material. The materials prepared were characterized by XRPD, TG/DTA analysis, SEM and optical microscopy. Titanium monoxide and several Magneli oxides, Ti4O7, Ti5O9 and Ti6O11, are successfully prepared. The results are very interesting because the EBONEX materials were prepared at lower than usual temperature, which would decrease the effective cost of production.

  7. Microarc oxidized TiO2 based ceramic coatings combined with cefazolin sodium/chitosan composited drug film on porous titanium for biomedical applications.

    Science.gov (United States)

    Wei, Daqing; Zhou, Rui; cheng, Su; Feng, Wei; Li, Baoqiang; Wang, Yaming; Jia, Dechang; Zhou, Yu; Guo, Haifeng

    2013-10-01

    Porous titanium was prepared by pressureless sintering of titanium beads with diameters of 100, 200, 400 and 600 μm. The results indicated that the mechanical properties of porous titanium changed significantly with different bead diameters. Plastic deformations such as necking phenomenon and dimple structure were observed on the fracture surface of porous titanium sintered by beads with diameter of 100 μm. However, it was difficult to find this phenomenon on the porous titanium with a titanium bead diameter of 600 μm. The microarc oxidized coatings were deposited on its surface to improve the bioactivity of porous titanium. Furthermore, the cefazolin sodium/chitosan composited films were fabricated on the microarc oxidized coatings for overcoming the inflammation due to implantation, showing good slow-release ability by addition of chitosan. And the release kinetic process of cefazolin sodium in composited films could be possibly fitted by a polynomial model. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Corrosion Behavior of Titanium Based Ceramic Coatings Deposited on Steels

    OpenAIRE

    Ali, Rania

    2016-01-01

    Titanium based ceramic films are increasingly used as coating materials because of their high hardness, excellent wear resistance and superior corrosion resistance. Using electrochemical and spectroscopic techniques, the electrochemical properties of different coatings deposited on different steels under different conditions were examined in this study. Thin films of titanium nitride (TiN), titanium diboride (TiB2), and titanium boronitride with different boron concentrations (TiBN-1&2) w...

  9. Aqueous Synthesis of Technetium-Doped Titanium Dioxide by Direct Oxidation of Titanium Powder, a Precursor for Ceramic Nuclear Waste Forms

    Energy Technology Data Exchange (ETDEWEB)

    Lukens, Wayne W. [Chemical; Saslow, Sarah A. [Earth

    2017-11-17

    Technetium-99 (Tc) is a problematic fission product that complicates the long-term disposal of nuclear waste due to its long half-life, high fission yield, and the environmental mobility of pertechnetate, its stable form in aerobic environments. One approach to preventing Tc contamination is through incorporation into durable waste forms based on weathering-resistant minerals such as rutile (titanium dioxide). Here, the incorporation of technetium into titanium dioxide by means of simple, aqueous chemistry is presented. X-ray absorption fine structure spectroscopy and diffuse reflectance spectroscopy indicate that Tc(IV) replaces Ti(IV) within the structure. Rather than being incorporated as isolated Tc(IV) ions, Tc is present as pairs of edge-sharing Tc(IV) octahedra similar to molecular Tc(IV) complexes such as [(H2EDTA)TcIV](u-O)2. Technetium-doped TiO2 was suspended in deionized water under aerobic conditions, and the Tc leached under these conditions was followed for 8 months. The normalized release rate of Tc (LRTc) from the TiO2 particles is low (3×10-6 g m-2 d-1), which illustrates the potential utility of TiO2 as waste form. However, the small size of the as-prepared TiO2 nanoparticles results in estimated retention of Tc for 104 years, which is only a fraction of the half-life of Tc (2×10-5 years).

  10. Porous ceramics out of oxides

    International Nuclear Information System (INIS)

    Bakunov, V.S.; Balkevich, V.L.; Vlasov, A.S.; Guzman, I.Ya.; Lukin, E.S.; Poluboyarinov, D.N.; Poliskij, R.Ya.

    1977-01-01

    A review is made of manufacturing procedures and properties of oxide ceramics intended for high-temperature thermal insulation and thermal protection applications. Presented are structural characteristics of porous oxide refractories and their properties. Strength and thermal conductivity was shown to depend upon porosity. Described is a procedure for manufacturing porous ceramic materials from aluminium oxide, zirconium dioxide, magnesium oxide, beryllium oxide. The thermal resistance of porous ceramics from BeO is considerably greater than that of other high-refractoriness oxides. Listed are areas of application for porous materials based on oxides

  11. Generation of amorphous ceramic capacitor coatings on titanium using a continuous sol-gel process

    International Nuclear Information System (INIS)

    Dixon, B.G.; Walsh, M.A. III; Phillips, P.G.; Morris, R.S.

    1995-01-01

    Thin amorphous films of ceramic capacitor materials were successfully deposited using sol-gel chemistry onto titanium wire using a continuous, computer controlled process. By repeatedly depositing and calcining very thin layers of material, smooth and even coats can be produced. Surface analyses revealed the layered nature of these thin coats, as well as the amorphous nature of the ceramic. The electrical properties of the better coatings, all composed of niobium, bismuth, zinc oxides, were then evaluated. copyright 1995 Materials Research Society

  12. Plasma electrolytic oxidation of Titanium Aluminides

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  13. Copper-silver-titanium-tin filler metal for direct brazing of structural ceramics

    Science.gov (United States)

    Moorhead, Arthur J.

    1988-04-05

    A method of joining ceramics and metals to themselves and to one another at about 800.degree. C. is described using a brazing filler metal consisting essentially of 35 to 50 at. % copper, 40 to 50 at. % silver, 1 to 15 at. % titanium, and 2 to 8 at. % tin. This method produces strong joints that can withstand high service temperatures and oxidizing environments.

  14. Copper-silver-titanium filler metal for direct brazing of structural ceramics

    Science.gov (United States)

    Moorhead, Arthur J.

    1987-01-01

    A method of joining ceramics and metals to themselves and to one another is described using a brazing filler metal consisting essentially of 35 to 50 atomic percent copper, 15 to 50 atomic percent silver and 10 to 45 atomic percent titanium. This method produces strong joints that can withstand high service temperatures and oxidizing environments.

  15. Mechanical and thermal cycling effects on the flexural strength of glass ceramics fused to titanium

    NARCIS (Netherlands)

    Vasquez, Vanessa; Ozcan, Mutlu; Nishioka, Renato; Souza, Rodrigo; Mesquita, Alfredo; Pavanelli, Carlos

    This study evaluated the effects of mechanical and thermal cycling on the flexural strength (ISO 9693) of three brands of ceramics fused to commercially pure titanium (cpTi). Metallic frameworks of 25 x 3 x 0.5 mm dimensions (N = 84) were cast in cpTi, followed by 150-mu m aluminum oxide airborne

  16. The titanium oxide phi system

    Science.gov (United States)

    Galehouse, D. C.; Davis, S. P.

    1980-01-01

    The phy system of titanium oxide has been studied in emission in the near-infrared, with the Fourier transform spectrometer at a resolution of 8000,000. Approximately 3000 lines from 25 bands of this system have been identified, including all five 0-0 and 0-1 bands corresponding to the five natural titanium isotopes. Eleven vibrational levels have been observed, and all bands have been rotationally analyzed. Band intensities are agreement with known isotopic abundances and calculated Franck-Condon factors.

  17. Reactor vessel using metal oxide ceramic membranes

    Science.gov (United States)

    Anderson, Marc A.; Zeltner, Walter A.

    1992-08-11

    A reaction vessel for use in photoelectrochemical reactions includes as its reactive surface a metal oxide porous ceramic membrane of a catalytic metal such as titanium. The reaction vessel includes a light source and a counter electrode. A provision for applying an electrical bias between the membrane and the counter electrode permits the Fermi levels of potential reaction to be favored so that certain reactions may be favored in the vessel. The electrical biasing is also useful for the cleaning of the catalytic membrane.

  18. Titanium oxide fever; De titaniumoxidekoorts

    Energy Technology Data Exchange (ETDEWEB)

    De Jonge, D.; Visser, J. [Afdeling Luchtkwaliteit, GGD Amsterdam, Amsterdam (Netherlands)

    2012-02-15

    One measure to improve air quality is to apply photo-catalytic substances that capture NOx onto the road surface or onto baffle boards alongside the roads. The effect of titanium oxide containing clinkers with coating was discussed in the report 'Demonstration project of air-purifying pavement in Hengelo, The Netherlands' that was published in May 2011. This article examines the way in which the effectiveness of this study was determined. Can titanium oxide containing clinkers and coatings indeed capture NOx?. [Dutch] Een van de maatregelen om de luchtkwaliteit te verbeteren is het aanbrengen van fotokatalytische stoffen waarmee NOx kan worden afgevangen op bijvoorbeeld wegdek of op geluidsschermen langs wegen. Over het effect van titaniumoxidehoudende straatklinkers en hierop aangebrachte coatings verscheen in mei 2011 het rapport 'Demonstration project of air-purifying pavement in Hengelo, The Netherlands'. Dit artikel gaat over de manier waarop de effectiviteit in het hiervoor genoemde onderzoek is bepaald. Kunnen titaniumoxidehoudende klinkers en coatings inderdaad NOx afvangen?.

  19. Dense high temperature ceramic oxide superconductors

    Science.gov (United States)

    Landingham, Richard L.

    1993-01-01

    Dense superconducting ceramic oxide articles of manufacture and methods for producing these articles are described. Generally these articles are produced by first processing these superconducting oxides by ceramic processing techniques to optimize materials properties, followed by reestablishing the superconducting state in a desired portion of the ceramic oxide composite.

  20. Use of aluminum oxides, titanium and cerium in the production of ceramic composites for protective coating of storage tanks and transportation of oil raw; Uso de oxidos de aluminio, titanio e cerio na producao de compositos ceramicos para revestimento protetor de tanques de armazenamento e transporte de petroleo cru

    Energy Technology Data Exchange (ETDEWEB)

    Rego, S.A.B.C.; Ferreira, R.A.S.; Yadava, Y.P., E-mail: sheila.abc.rego@hotmail.com [Universidade Federal de Pernambuco (UFPE), PE (Brazil). Centro de Tecnologia e Geociencias

    2012-07-01

    The deployment of the Abreu e Lima refinery in the port of SUAPE - PE will increase the need to store oil in the region, it is essential to research and develop new materials inert to chemical attack promoted by oil. In this work, we produce the ceramic composite alumina-titania, ceria of high mechanical strength which is observed that with additions of titanium oxide in the order of 15% and 20% better results are obtained as possibly indicating these composites suitable for use in coating ceramic storage tanks of crude oil. (author)

  1. Green oxidations: Titanium dioxide induced tandem oxidation coupling reactions

    OpenAIRE

    Jeena, Vineet; Robinson, Ross S

    2009-01-01

    Summary The application of titanium dioxide as an oxidant in tandem oxidation type processes is described. Under microwave irradiation, quinoxalines have been synthesized in good yields from the corresponding ?-hydroxyketones.

  2. Amorphous titanium-oxide supercapacitors

    Science.gov (United States)

    Fukuhara, Mikio; Kuroda, Tomoyuki; Hasegawa, Fumihiko

    2016-10-01

    The electric capacitance of an amorphous TiO2-x surface increases proportionally to the negative sixth power of the convex diameter d. This occurs because of the van der Waals attraction on the amorphous surface of up to 7 mF/cm2, accompanied by extreme enhanced electron trapping resulting from both the quantum-size effect and an offset effect from positive charges at oxygen-vacancy sites. Here we show that a supercapacitor, constructed with a distributed constant-equipment circuit of large resistance and small capacitance on the amorphous TiO2-x surface, illuminated a red LED for 37 ms after it was charged with 1 mA at 10 V. The fabricated device showed no dielectric breakdown up to 1,100 V. Based on this approach, further advances in the development of amorphous titanium-dioxide supercapacitors might be attained by integrating oxide ribbons with a micro-electro mechanical system.

  3. Laser induced single spot oxidation of titanium

    Energy Technology Data Exchange (ETDEWEB)

    Jwad, Tahseen, E-mail: taj355@bham.ac.uk; Deng, Sunan; Butt, Haider; Dimov, S.

    2016-11-30

    Highlights: • A new high resolution laser induced oxidation (colouring) method is proposed (single spot oxidation). • The method is applied to control oxide films thicknesses and hence colours on titanium substrates in micro-scale. • The method enable imprinting high resolution coloured image on Ti substrate. • Optical and morphological periodic surface structures are also produced by an array of oxide spots using the proposed method. • Colour coding of two colours into one field is presented. - Abstract: Titanium oxides have a wide range of applications in industry, and they can be formed on pure titanium using different methods. Laser-induced oxidation is one of the most reliable methods due to its controllability and selectivity. Colour marking is one of the main applications of the oxidation process. However, the colourizing process based on laser scanning strategies is limited by the relative large processing area in comparison to the beam size. Single spot oxidation of titanium substrates is proposed in this research in order to increase the resolution of the processed area and also to address the requirements of potential new applications. The method is applied to produce oxide films with different thicknesses and hence colours on titanium substrates. High resolution colour image is imprinted on a sheet of pure titanium by converting its pixels’ colours into laser parameter settings. Optical and morphological periodic surface structures are also produced by an array of oxide spots and then analysed. Two colours have been coded into one field and the dependencies of the reflected colours on incident and azimuthal angles of the light are discussed. The findings are of interest to a range of application areas, as they can be used to imprint optical devices such as diffusers and Fresnel lenses on metallic surfaces as well as for colour marking.

  4. Laser induced single spot oxidation of titanium

    International Nuclear Information System (INIS)

    Jwad, Tahseen; Deng, Sunan; Butt, Haider; Dimov, S.

    2016-01-01

    Highlights: • A new high resolution laser induced oxidation (colouring) method is proposed (single spot oxidation). • The method is applied to control oxide films thicknesses and hence colours on titanium substrates in micro-scale. • The method enable imprinting high resolution coloured image on Ti substrate. • Optical and morphological periodic surface structures are also produced by an array of oxide spots using the proposed method. • Colour coding of two colours into one field is presented. - Abstract: Titanium oxides have a wide range of applications in industry, and they can be formed on pure titanium using different methods. Laser-induced oxidation is one of the most reliable methods due to its controllability and selectivity. Colour marking is one of the main applications of the oxidation process. However, the colourizing process based on laser scanning strategies is limited by the relative large processing area in comparison to the beam size. Single spot oxidation of titanium substrates is proposed in this research in order to increase the resolution of the processed area and also to address the requirements of potential new applications. The method is applied to produce oxide films with different thicknesses and hence colours on titanium substrates. High resolution colour image is imprinted on a sheet of pure titanium by converting its pixels’ colours into laser parameter settings. Optical and morphological periodic surface structures are also produced by an array of oxide spots and then analysed. Two colours have been coded into one field and the dependencies of the reflected colours on incident and azimuthal angles of the light are discussed. The findings are of interest to a range of application areas, as they can be used to imprint optical devices such as diffusers and Fresnel lenses on metallic surfaces as well as for colour marking.

  5. The studies of a new ceramic composite — (Zr0.92Y0.08)O1.96 dispersed lanthanum titanium aluminium oxide

    International Nuclear Information System (INIS)

    Zhang, Peng; Choy, Kwang-leong

    2016-01-01

    A new ceramic composite (Zr 0.92 Y 0.08 )O 1.96 dispersed in LaTi 2 Al 9 O 19 as a thermal barrier material was synthesized by the hybrid sol–gel method. The composite ceramic has good thermochemical stability up to 1500 °C. The thermal conductivity of composite ceramic is circa. 1.0 W/m·K at ambient temperature and the coefficients of thermal expansion are very stable and comparable to (Zr 0.92 Y 0.08 )O 1.96 about 10.7 × 10 −6 K −1 at 1223 K. The sintering resistance and mechanical properties become better after being dispersed. Therefore, the new ceramic composite synthesized by hybrid sol–gel method can be a promising candidate as a thermal barrier material on Ni-based superalloy. - Highlights: • New composite 4 mol% yttria stabilized zirconia (4YSZ) dispersed LaTi 2 Al 9 O 19 (LTA) is synthesized by a hybrid sol-gel method. • The new ceramic composite shows good thermochemical stability up to 1500 o C. • The thermal conductivity of the new ceramic composite is lower than each component at ambient temperature. • The coefficient of thermal expansion of 4YSZ dispersed in LTA (LTA-4YSZ) is comparable to 4YSZ. • Compared with LTA and 4YSZ, LTA-4YSZ has the best sintering resistance. • The Young’s Modulus of LTA-4YSZ composite becomes lower while the hardness becomes higher.

  6. Titanium diboride ceramic fiber composites for Hall-Heroult cells

    Science.gov (United States)

    Besmann, T.M.; Lowden, R.A.

    1990-05-29

    An improved cathode structure is described for Hall-Heroult cells for the electrolytic production of aluminum metal. This cathode structure is a preform fiber base material that is infiltrated with electrically conductive titanium diboride using chemical vapor infiltration techniques. The structure exhibits good fracture toughness, and is sufficiently resistant to attack by molten aluminum. Typically, the base can be made from a mat of high purity silicon carbide fibers. Other ceramic or carbon fibers that do not degrade at temperatures below about 1000 C can be used.

  7. Thermochemically active iron titanium oxide materials

    Energy Technology Data Exchange (ETDEWEB)

    Coker, Eric Nicholas; Miller, James E.

    2018-01-16

    A thermal oxidation-reduction cycle is disclosed that uses iron titanium oxide as the reactive material. The cycle may be used for the thermal splitting of water and/or carbon dioxide to form hydrogen and/or carbon monoxide. The formed compounds may be used as syngas precursors to form fuels.

  8. Effect of investment type and mold temperature on casting accuracy and titanium-ceramic bond.

    Science.gov (United States)

    Leal, Mônica Barbosa; Pagnano, Valéria Oliveira; Bezzon, Osvaldo Luiz

    2013-01-01

    This study evaluated the casting accuracy of crown margins and metal-ceramic shear bond strength (SBS) of pure titanium injected into casting molds made using 2 investment types at 3 mold temperatures. Sixty crown (30-degree beveled finish line) and 60 cylinder (5mm diameter × 8mm high) patterns were divided into 6 groups (n=10), and cast using a phosphate-bonded investment (P) and a magnesium oxide-bonded investment (U), at 400°C (groups P400 and U400), 550°C (groups P550 and U550) and 700°C (groups P700 and U700) mold temperatures. Crown margins were recorded in impression material, the degree of marginal rounding was measured and margin length deficiencies (µm) were calculated. Titanium-ceramic specimens were prepared using Triceram ceramic (2mm high) and SBS was tested. Failure modes were assessed by optical microscopy. Data were subjected to two-way ANOVA and Tukey's HSD test (α=0.05). For casting accuracy, expressed by marginal deficiency (µm), investment U provided more accurate results (64 ± 11) than P (81 ± 23) (pcasting accuracy for U700 (55 ± 7) and worse for P700 (109 ± 18). Casting accuracy at 700°C (82 ± 31) was significantly different from 400°C (69 ± 9) and 550°C (68 ± 9) (pcasting accuracy than investment P. The SBS was similar for all combinations of investments and temperatures.

  9. Determination of porosity in supports for ceramic membranes of titanium dioxide by gamma spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Siciliano, Umberto C.C.S.; Oliveira, Elizabeth E.M.; Brandão, Luís E.B.; Carvalho, Paulo V.R., E-mail: ucsiciliano@gmail.com, E-mail: eemo@ien.gov.br, E-mail: brandao@ien.gov.br, E-mail: paulov@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2017-07-01

    Membrane separation processes (MSP) have been widely used to fractionate, concentrate and purity solutions, such as: food industry, pharmaceutical, water desalination and for treatment of the radioactive liquid waste in the nuclear industry. The MSP are more economical than traditional methods because most of them are athermic. Increased membrane application has led to the expansion of the manufacturing technology knowledge base, resulting in membranes with high permeability, improved selectivity and long-term stability. The demand for high operating temperatures and chemical resistance have stimulated the development of inorganic structures, mainly porous ceramics. The materials most used to obtain ceramic membranes are oxides like Ab0{sub 3}, Si0{sub 2}, Zr0{sub 2} and Ti0{sub 2} or combination of these. Despite the favorable characteristics, ceramic membranes has not been applied extensively, mainly due to the difficulty of obtaining porous structures without cracks and with adequate pore size. The objective of this work is obtain a support of titanium oxide using potato starch as a pore former. The titanium oxide used is commercial, with average particle size of 0.13 μm. Three suspensions were prepared containing 0,5 and 10 % of the potato starch and the drying in spray dryer, obtaining a homogeneous and granulated powder, with flow ability suitable for compaction. The supports were uniaxial pressing with l.5 kgf.cm{sup -2} and sintering at temperatures of 1050, 1100 and 1150 °C for 1h in oven resistance. The results showed that the porosity obtained by gamma ray transmission method was approximately 50%. This value is within range for applications as membrane support. (author)

  10. Pyrolytic carbon coating for cytocompatibility of titanium oxide nanoparticles: a promising candidate for medical applications

    International Nuclear Information System (INIS)

    Behzadi, Shahed; Simchi, Abdolreza; Imani, Mohammad; Yousefi, Mohammad; Galinetto, Pietro; Amiri, Houshang; Stroeve, Pieter; Mahmoudi, Morteza

    2012-01-01

    Nanoparticles for biomedical use must be cytocompatible with the biological environment that they are exposed to. Current research has focused on the surface functionalization of nanoparticles by using proteins, polymers, thiols and other organic compounds. Here we show that inorganic nanoparticles such as titanium oxide can be coated by pyrolytic carbon (PyC) and that the coating has cytocompatible properties. Pyrolization and condensation of methane formed a thin layer of pyrolytic carbon on the titanium oxide core. The formation of the PyC shell retards coalescence and sintering of the ceramic phase. Our MTT assay shows that the PyC-coated particles are cytocompatible at employed doses. (paper)

  11. Temperature effect on surface oxidation of titanium

    International Nuclear Information System (INIS)

    Vaquilla, I.; Barco, J.L. del; Ferron, J.

    1990-01-01

    The effect of temperature on the first stages of the superficial oxidation of polycrystalline titanium was studied using both Auger electron spectroscopy (AES) and emission shreshold (AEAPS). The number of compounds present on the surface was determined by application of the factor analysis technique. Reaction evolution was followed through the relative variation of Auger LMM and LMV transitions which are characteristic of titanium. Also the evolution of the chemical shift was determined by AEAPS. The amount of oxygen on the surface was quantified using transition KLL of oxygen. It was found that superficial oxidation depends on temperature. As much as three different compounds were determined according to substrate temperature and our exposure ranges. (Author). 7 refs., 5 figs

  12. NOVEL EMBEDDED CERAMIC ELECTRODE SYSTEM TO ACTIVATE NANOSTRUCTURED TITANIUM DIOXIDE FOR DEGRADATION OF MTBE

    Science.gov (United States)

    A novel reactor combining a flame-deposited nanostructured titanium dioxide film and a set of embedded ceramic electrodes was designed, developed and tested for degradation of methyl tert-butyl ether (MTBE) in water. On applying a voltage to the ceramic electrodes, a surface coro...

  13. Titanium

    Science.gov (United States)

    Woodruff, Laurel G.; Bedinger, George M.; Piatak, Nadine M.; Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.

    2017-12-19

    Titanium is a mineral commodity that is essential to the smooth functioning of modern industrial economies. Most of the titanium produced is refined into titanium dioxide, which has a high refractive index and is thus able to impart a durable white color to paint, paper, plastic, rubber, and wallboard. Because of their high strength-to-weight ratio and corrosion resistance, titanium metal and titanium metal alloys are used in the aerospace industry as well as for welding rod coatings, biological implants, and consumer goods.Ilmenite and rutile are currently the principal titanium-bearing ore minerals, although other minerals, including anatase, perovskite, and titanomagnetite, could have economic importance in the future. Ilmenite is currently being mined from two large magmatic deposits hosted in rocks of Proterozoic-age anorthosite plutonic suites. Most rutile and nearly one-half of the ilmenite produced are from heavy-mineral alluvial, fluvial, and eolian deposits. Titanium-bearing minerals occur in diverse geologic settings, but many of the known deposits are currently subeconomic for titanium because of complications related to the mineralogy or because of the presence of trace contaminants that can compromise the pigment production process.Global production of titanium minerals is currently dominated by Australia, Canada, Norway, and South Africa; additional amounts are produced in Brazil, India, Madagascar, Mozambique, Sierra Leone, and Sri Lanka. The United States accounts for about 4 percent of the total world production of titanium minerals and is heavily dependent on imports of titanium mineral concentrates to meet its domestic needs.Titanium occurs only in silicate or oxide minerals and never in sulfide minerals. Environmental considerations for titanium mining are related to waste rock disposal and the impact of trace constituents on water quality. Because titanium is generally inert in the environment, human health risks from titanium and titanium

  14. Structural behaviour of nitrogen in oxide ceramics

    International Nuclear Information System (INIS)

    Ghauri, K.M.

    1997-01-01

    The solubility of nitrogen in molten oxides has significant consideration for two quite different types of engineering materials. The implication of a knowledge of the role of nitrogen in these oxides for refining high nitrogen steels in obvious but similar nitrogen-bearing oxide melts are of critical importance in the densification of silicon nitride ceramics. Present paper discusses structural behaviour and phase equilibria qualitatively in the light of knowledge available on slag structure through infrared and x-ray diffraction. Nitrogen solubility in glasses and related sialon based ceramics may be of paramount importance to understand the role of nitrogen in these materials as these oxides are similar in composition, structure and characteristics to sintering glasses in nitrogen ceramics. It is quite logical to infer that the same oxide model can be applied in order to massively produce nitrogen alloyed steels which are actively competing to be the materials of the next century. (author)

  15. Microwave processing of ceramic oxide filaments

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, G.J.; Katz, J.D. [Los Alamos National Laboratory, NM (United States)

    1995-05-01

    The objective of the microwave filament processing project is to develop microwave techniques at 2.45 GHZ to manufacture continuous ceramic oxide filaments. Microwave processing uses the volumetric absorption of microwave power in oxide filament tows to drive off process solvents, to burn out organic binders, and to sinter the dried fibers to produce flexible, high-strength ceramic filaments. The technical goal is to advance filament processing technology by microwave heating more rapidly with less energy and at a lower cost than conventional processing, but with the same quality as conventional processing. The manufacturing goal is to collaborate with the 3M Company, a US manufacturer of ceramic oxide filaments, to evaluate the technology using a prototype filament system and to transfer the microwave technology to the 3M Company.

  16. Titanium oxidation by rf inductively coupled plasma

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  17. Electrochemical Thinning for Anodic Aluminum Oxide and Anodic Titanium Oxide

    Energy Technology Data Exchange (ETDEWEB)

    Lee, In Hae; Jo, Yun Kyoung; Kim, Yong Tae; Tak, Yong Sug; Choi, Jin Sub [Inha University, Incheon (Korea, Republic of)

    2012-05-15

    For given electrolytes, different behaviors of anodic aluminum oxide (AAO) and anodic titanium oxide (ATO) during electrochemical thinning are explained by ionic and electronic current modes. Branched structures are unavoidably created in AAO since the switch of ionic to electronic current is slow, whereas the barrier oxide in ATO is thinned without formation of the branched structures. In addition, pore opening can be possible in ATO if chemical etching is performed after the thinning process. The thinning was optimized for complete pore opening in ATO and potential-current behavior is interpreted in terms of ionic current-electronic current switching.

  18. Atomic profile imaging of ceramic oxide surfaces

    International Nuclear Information System (INIS)

    Bursill, L.A.; Peng JuLin; Sellar, J.R.

    1989-01-01

    Atomic surface profile imaging is an electron optical technique capable of revealing directly the surface crystallography of ceramic oxides. Use of an image-intensifier with a TV camera allows fluctuations in surface morphology and surface reactivity to be recorded and analyzed using digitized image data. This paper reviews aspects of the electron optical techniques, including interpretations based upon computer-simulation image-matching techniques. An extensive range of applications is then presented for ceramic oxides of commercial interest for advanced materials applications: including uranium oxide (UO 2 ); magnesium and nickel oxide (MgO,NiO); ceramic superconductor YBa 2 Cu 3 O 6.7 ); barium titanate (BaTiO 3 ); sapphire (α-A1 2 O 3 ); haematite (α-Fe-2O 3 ); monoclinic, tetragonal and cubic monocrystalline forms of zirconia (ZrO 2 ), lead zirconium titanate (PZT + 6 mol.% NiNbO 3 ) and ZBLAN fluoride glass. Atomic scale detail has been obtained of local structures such as steps associated with vicinal surfaces, facetting parallel to stable low energy crystallographic planes, monolayer formation on certain facets, relaxation and reconstructions, oriented overgrowth of lower oxides, chemical decomposition of complex oxides into component oxides, as well as amorphous coatings. This remarkable variety of observed surface stabilization mechanisms is discussed in terms of novel double-layer electrostatic depolarization mechanisms, as well as classical concepts of the physics and chemistry of surfaces (ionization and affinity energies and work function). 46 refs., 16 figs

  19. Production of superconducting ceramic oxides by coprecipitation

    International Nuclear Information System (INIS)

    Bizaio, L.R.; Lima, M.A.F. de; Figueiredo Jardim, R.de; Pinheiro, E.A.; Galembeck, F.

    1988-01-01

    An alternative method for production of ceramic oxides is described. The method consist in the coprecipitation reaction of metallic ions with oxalic acid. The obtainment samples present additional phases characterized by X-rays and optical microscopy. (C.G.C.) [pt

  20. Effect of sintering temperatures on titanium matrix composites reinforced by ceramic particles

    Energy Technology Data Exchange (ETDEWEB)

    Romero, F.; Amigo, V.; Busquets, D.; Klyatskina, E. [Mechanical and Materials Engineering Department. Polytechnical University of Valencia, Valencia (Spain)

    2005-07-01

    Titanium and titanium composites have a potential use in aerospace and biotechnology industries, and nowadays in others like sports and fashion ones. In this work composite materials, based on titanium matrix reinforced with ceramic particles, have been developed. PM route is used to obtain compact and sintered samples. TiN and TiAl powders, are milled with Ti powder in different volumetric percentages in a ball mill. These mixtures are pressed in a uniaxial press and sintered in a vacuum furnace at different temperatures between 1180 to 1220 deg. C. Porosity of samples is analysed, before and after the sintering process, by Archimedes technique and by image analysis. Mechanical properties and the reinforcement particles influence in the titanium matrix are studied by flexion test in green and sintered states, and by hardness and microhardness tests. Complimentarily, a microstructural analysis is carried out by optical and electron microscopy, and the reactivity between the reinforce particles and titanium matrix are studied. (authors)

  1. Hydrous titanium oxide-supported catalysts

    International Nuclear Information System (INIS)

    Dosch, R.G.; Stohl, F.V.; Richardson, J.T.

    1990-01-01

    Catalysts were prepared on hydrous titanium oxide (HTO) supports by ion exchange of an active metal for Na + ions incorporated in the HTO support during preparation by reaction with the parent Ti alkoxide. Strong active metal-HTO interactions as a result of the ion exchange reaction can require significantly different conditions for activation as compared to catalysts prepared by more widely used incipient wetness methods. The latter catalysts typically involve conversion or while the HTO catalysts require the alteration of electrostatic bonds between the metal and support with subsequent alteration of the support itself. In this paper, the authors discuss the activation, via sulfidation or reduction, of catalysts consisting of Co, Mo, or Ni-Mo dispersed on HTO supports by ion exchange. Correlations between the activation process and the hydrogenation, hydrodeoxygenation, and hydrodesulfurization activities of the catalysts are presented

  2. Lutetium oxide-based transparent ceramic scintillators

    Science.gov (United States)

    Seeley, Zachary; Cherepy, Nerine; Kuntz, Joshua; Payne, Stephen A.

    2016-01-19

    In one embodiment, a transparent ceramic of sintered nanoparticles includes gadolinium lutetium oxide doped with europium having a chemical composition (Lu.sub.1-xGd.sub.x).sub.2-YEu.sub.YO.sub.3, where X is any value within a range from about 0.05 to about 0.45 and Y is any value within a range from about 0.01 to about 0.2, and where the transparent ceramic exhibits a transparency characterized by a scatter coefficient of less than about 10%/cm. In another embodiment, a transparent ceramic scintillator of sintered nanoparticles, includes a body of sintered nanoparticles including gadolinium lutetium oxide doped with a rare earth activator (RE) having a chemical composition (Lu.sub.1-xGd.sub.x).sub.2-YRE.sub.YO.sub.3, where RE is selected from the group consisting of: Sm, Eu, Tb, and Dy, where the transparent ceramic exhibits a transparency characterized by a scatter coefficient of less than about 10%/cm.

  3. Molecular geometries and relative stabilities of titanium oxide and gold-titanium oxide clusters

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, Rohan J.; Falcinella, Alexander; Metha, Gregory F., E-mail: greg.metha@adelaide.edu.au

    2016-09-30

    Titanium oxide and gold-titanium oxide clusters of stoichiometry M{sub x}O{sub y} (M{sub x} = Ti{sub 3}, Ti{sub 4} & AuTi{sub 3}; y = 0 − (2x + 2)) have been investigated using density functional theory. Geometries of determined global energy minimum structures are reported and other isomers predicted up to 0.5 eV higher in energy. The Ti{sub 3}O{sub n} geometries build upon a triangular Ti{sub 3} motif, while Ti{sub 4}O{sub n} stoichiometries template upon a pseudo-tetrahedral Ti{sub 4} structure. Addition of a gold atom to the Ti{sub 3}O{sub n} series does not significantly alter the cluster geometry, with the gold atom preferentially binding to titanium atoms over oxygen atoms. Adiabatic ionization energies, electron affinities and HOMO/LUMO energies increase in magnitude with increasing oxygenation. The HOMO-LUMO energy gaps reach the bulk anatase band gap energy at stoichiometry (Au)Ti{sub m}O{sub 2m−1}, and increase above this upon further oxygen addition. The most stable structural moieties are found to be a cage-like, C{sub 3v} symmetric Ti{sub 4}O{sub 6/7} geometry and a Ti{sub 3}O{sub 6} structure with an η{sup 3}-bound oxygen atom.

  4. Characterization for rbs of Titanium Oxide thin films grown by Dip Coating in a coloidal suspension of nano structured Titanium Oxide

    International Nuclear Information System (INIS)

    Pedrero, E.; Vigil, E.; Zumeta, I.

    1999-01-01

    The depth of Titanium Oxide thin films grown by Dip Coating in a coloidal suspension of nano structured Titanium Oxide was characterized using Rutherford Backscattering Spectrometry. Film depths are compared in function of bath and suspension parameters

  5. A Novel Technique for the Connection of Ceramic and Titanium Implant Components Using Glass Solder Bonding

    Directory of Open Access Journals (Sweden)

    Enrico Mick

    2015-07-01

    Full Text Available Both titanium and ceramic materials provide specific advantages in dental implant technology. However, some problems, like hypersensitivity reactions, corrosion and mechanical failure, have been reported. Therefore, the combining of both materials to take advantage of their pros, while eliminating their respective cons, would be desirable. Hence, we introduced a new technique to bond titanium and ceramic materials by means of a silica-based glass ceramic solder. Cylindrical compound samples (Ø10 mm × 56 mm made of alumina toughened zirconia (ATZ, as well as titanium grade 5, were bonded by glass solder on their end faces. As a control, a two-component adhesive glue was utilized. The samples were investigated without further treatment, after 30 and 90 days of storage in distilled water at room temperature, and after aging. All samples were subjected to quasi-static four-point-bending tests. We found that the glass solder bonding provided significantly higher bending strength than adhesive glue bonding. In contrast to the glued samples, the bending strength of the soldered samples remained unaltered by the storage and aging treatments. Scanning electron microscopy (SEM and energy-dispersive X-ray (EDX analyses confirmed the presence of a stable solder-ceramic interface. Therefore, the glass solder technique represents a promising method for optimizing dental and orthopedic implant bondings.

  6. Effect of laser welding on the titanium ceramic tensile bond strength

    Directory of Open Access Journals (Sweden)

    Rodrigo Galo

    2011-08-01

    Full Text Available Titanium reacts strongly with elements, mainly oxygen at high temperature. The high temperature of titanium laser welding modifies the surface, and may interfere on the metal-ceramic tensile bond strength. OBJECTIVE: The influence of laser welding on the titanium-ceramic bonding has not yet been established. The purpose of this in vitro study was to analyze the influence of laser welding applied to commercially pure titanium (CpTi substructure on the bond strength of commercial ceramic. The influence of airborne particle abrasion (Al2O3 conditions was also studied. MATERIAL AND METHODS: Forty CpTi cylindrical rods (3 mm x 60 mm were cast and divided into 2 groups: with laser welding (L and without laser welding (WL. Each group was divided in 4 subgroups, according to the size of the particles used in airborne particle abrasion: A - Al2O3 (250 µm; B - Al2O3 (180 µm; C - Al2O3 (110 µm; D - Al2O3 (50 µm. Ceramic rings were fused around the CpTi rods. Specimens were invested and their tensile strength was measured at fracture with a universal testing machine at a crosshead speed of 2.0 mm/min and 200 kgf load cell. Statistical analysis was carried out with analysis of variance and compared using the independent t test (p<0.05. RESULTS: Significant differences were found among all subgroups (p<0.05. The highest and the lowest bond strength means were recorded in subgroups WLC (52.62 MPa and LD (24.02 MPa, respectively. CONCLUSION: Airborne particle abrasion yielded significantly lower bond strength as the Al2O3 particle size decreased. Mechanical retention decreased in the laser-welded specimens, i.e. the metal-ceramic tensile bond strength was lower.

  7. Anticoagulation and endothelial cell behaviors of heparin-loaded graphene oxide coating on titanium surface

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Chang-Jiang, E-mail: panchangjiang@hyit.edu.cn [Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huai' an 223003 (China); Pang, Li-Qun [Department of General Surgery, Huai' an First People' s Hospital, Nanjing Medical University, Huai' an 223300 (China); Gao, Fei [Zhejiang Zylox Medical Devices Co., Ltd., Hangzhou 310000 (China); Wang, Ya-Nan; Liu, Tao; Ye, Wei; Hou, Yan-Hua [Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huai' an 223003 (China)

    2016-06-01

    Owing to its unique physical and chemical properties, graphene oxide (GO) has attracted tremendous interest in many fields including biomaterials and biomedicine. The purpose of the present study is to investigate the endothelial cell behaviors and anticoagulation of heparin-loaded GO coating on the titanium surface. To this end, the titanium surface was firstly covered by the polydopamine coating followed by the deposition of the GO coating. Heparin was finally loaded on the GO coating to improve the blood compatibility. The results of attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) indicated that the heparin-loaded GO coating was successfully created on the titanium surface. The scanning electron microscopy (SEM) images indicated that a relative uniform GO coating consisting of multilayer GO sheets was formed on the substrate. The hydrophilicity of the titanium surface was enhanced after the deposition of GO and further improved significantly by the loading heparin. The GO coating can enhance the endothelial cell adhesion and proliferation as compared with polydopamine coating and the blank titanium. Loading heparin on the GO coating can significantly reduce the platelet adhesion and prolong the activated partial thromboplastin time (APTT) while not influence the endothelial cell adhesion and proliferation. Therefore, the heparin-loaded GO coating can simultaneously enhance the cytocompatibility to endothelial cells and blood compatibility of biomaterials. Because the polydopamine coating can be easily prepared on most of biomaterials including polymer, ceramics and metal, thus the approach of the present study may open up a new window of promising an effective and efficient way to promote endothelialization and improve the blood compatibility of blood-contact biomedical devices such as intravascular stents. - Highlights: • Heparin-loaded graphene oxide coating was

  8. Oxidized zirconium on ceramic; Catastrophic coupling.

    Science.gov (United States)

    Ozden, V E; Saglam, N; Dikmen, G; Tozun, I R

    2017-02-01

    Oxidized zirconium (Oxinium™; Smith & Nephew, Memphis, TN, USA) articulated with polyethylene in total hip arthroplasty (THA) appeared to have the potential to reduce wear dramatically. The thermally oxidized metal zirconium surface is transformed into ceramic-like hard surface that is resistant to abrasion. The exposure of soft zirconium metal under hard coverage surface after the damage of oxidized zirconium femoral head has been described. It occurred following joint dislocation or in situ succeeding disengagement of polyethylene liner. We reported three cases of misuse of Oxinium™ (Smith & Nephew, Memphis, TN, USA) heads. These three cases resulted in catastrophic in situ wear and inevitable failure although there was no advice, indication or recommendation for this use from the manufacturer. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  9. Ceramic modifications of porous titanium: effects on macrophage activation.

    Science.gov (United States)

    Scislowska-Czarnecka, A; Menaszek, E; Szaraniec, B; Kolaczkowska, E

    2012-12-01

    Porous titanium is one of the most widely used implant materials because of its mechanical properties, however, it is also characterised by low bioactivity. To improve the above parameter we prepared three modifications of the porous (30 wt%) titanium (Ti) surface by covering it with bioactive hydroxyapatite (HA), bioglass (BG) and calcium silicate (CS). Subsequently we tested the impact of the modifications on macrophages directing the inflammatory response that might compromise the implant bioactivity. In the study we investigated the in vitro effects of the materials on murine cell line RAW 264.7 macrophage adherence, morphology and activation (production/release of metalloproteinase MMP-9 and pro- and anti-inflammatory cytokines). CS Ti decreased the macrophage adherence and up-regulated the release of several pro-inflammatory mediators, including TNF-α, IL-6, IL-12. Also HA Ti reduced the cell adherence but other parameters were generally not increased, except of TNF-α. In contrast, BG Ti improved macrophage adherence and either decreased production of multiple mediators (MMP-9, TNF-α, IFN-γ, MCP-1) or did not change it in comparison to the porous titanium. We can conclude that analyzing the effects on the inflammatory response initiated by macrophages in vitro, calcium silicate did not improve the biological properties of the porous titanium. The improved bioactivity of titanium was, however, achieved by the application of the hydroxyapatite and bioglass layers. The present in vitro results suggest that these materials, HA Ti and especially BG Ti, may be suitable for in vivo application and thus justify their further investigation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Ion irradiation studies of oxide ceramics

    International Nuclear Information System (INIS)

    Zinkle, S.J.

    1988-01-01

    This paper presents the initial results of an investigation of the depth-dependent microstructures of three oxide ceramics following ion implantation to moderate doses. The implantations were performed using ion species that occur as cations in the target material; for example, Mg + ions were used for MgO and MgAl 2 O 4 (spinel) irradiations. This minimized chemical effects associated with the implantation and allowed a more direct evaluation to be made of the effects of implanted ions on the microstructure. 11 refs., 14 figs

  11. Additively Manufactured Titanium and Cobalt-Chromium Implant Frameworks: Fit and Effect of Ceramic Veneering.

    Science.gov (United States)

    Svanborg, Per; Eliasson, Alf; Stenport, Victoria

    The purpose of this study was to evaluate the fit of additively manufactured cobalt-chromium and titanium and CNC-milled titanium frameworks before and after ceramic veneering. Ten stone casts simulating an edentulous maxilla provided with six abutment analogs were produced. For each stone cast, one additively manufactured cobalt-chromium framework (AM CoCr) and one titanium framework (AM Ti) were fabricated. The fit was analyzed with a coordinate measuring machine in three dimensions (x, y, and z axes) using best-fit virtual matching of center point coordinates, before and after ceramic veneering. CNC-milled titanium frameworks (CNC Ti) and earlier results from CNC-milled cobalt-chromium frameworks (CNC CoCr) were used for comparison. All frameworks presented minor misfit before and after veneering in the horizontal plane (x- and y-axes) between 2.9 and 13.5 μm and in the vertical plane (z-axis) between 1.6 and 5.4 μm. Ceramic veneering affected the fit of all groups of frameworks. Both AM Ti and AM CoCr presented significantly smaller distortion in the vertical plane compared with the CNC-milled frameworks. Implant-supported frameworks can be produced in either Ti or CoCr using either CNC milling or additive manufacturing with a fit well within the range of 20 μm in the horizontal plane and 10 μm in the vertical plane. The fit of frameworks of both materials and production techniques are affected by the ceramic veneering procedure to a small extent.

  12. Novel titanium dioxide ceramics containing bismuth and antimony

    Directory of Open Access Journals (Sweden)

    Zhenwei Li

    2017-06-01

    Full Text Available Here, we developed one kind of novel TiO2 ceramics with colossal dielectric constant by chemical modifications (Bi3+ and Sb5+, and discussed the physical origin for giant dielectric constant. Effects of Bi and/or Sb on their microstructure, dielectric properties as well as its frequency and temperature stability were studied in detail. It was found that their dielectric properties are strongly sensitive to (Bi,Sb contents, and colossal dielectric permittivity (CP (104∼105 together with low dielectric loss (∼5.7% can be obtained in a wide composition range. In addition, all the ceramics possessed good frequency (102∼106 Hz and temperature (−150–200 °C stability of dielectric properties. In addition, the defects caused by the Bi volatilization may be the reason for higher dielectric properties of (Bi0.5Sb0.5xTi1−xO2 ceramics with respect to (A0.5Sb0.5xTi1−xO2 (A = In, Pr, Dy, Sm, Gd, Yb, Ga, Al, Fe or Sc. According to the results of complex impedance and XPS, the electron-pinned defect-dipoles may be suitable to explain the CP phenomenon, and oxygen vacancies-induced by Bi3+&Sb5+ substitution for Ti4+ should be responsible for conduction mechanism. We believe that this profound investigation can benefit the development of TiO2 ceramics as a CP material.

  13. Comparing Titanium Release from Ceramic Tiles using a waste material characterization test - Influence of Calcium and Organic Matter concentrations

    DEFF Research Database (Denmark)

    Heggelund, Laura Roverskov; Hansen, Steffen Foss; Astrup, Thomas Fruergaard

    2015-01-01

    Nanomaterials are beneficial in the building industry to enhance or add certain features to commonly used materials. One example is the use of nano-titanium dioxide in the surface coating of ceramic tiles, to make the tiles surface self-cleaning. At the end of life stage, ceramic tiles might...... to assess if nano-titanium dioxide coated ceramic tiles are suitable for depositing in a landfill or not. Specifically, we used compliance batch test method, which is a simple test evaluating the release from a solid material to an aqueous media during 24 hrs. If nano-Ti particles are released from solid...... immediately after the 24 hrs. test using single particle ICPMS and Transmission Electron Microscopy imaging. The preliminary results suggest that nanoparticulate titanium is released from both tiles – with and without nano-titanium dioxide coating. The size distributions of the released particles are similar...

  14. Characterization of ceramics of titanium oxide to treatment of effluents from nuclear area; Caracterização de suportes cerâmicos de óxido de titânio para tratamento de efluentes da área nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Milena Hudson da, E-mail: milenahudsons@gmail.com [Engenharia Química, Universidade Federal do Rio de Janeiro, RJ (Brazil); Oliveira, Elizabeth E. de Mello, E-mail: eemo@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2017-07-01

    Membrane separation processes (PSM) have become increasingly important technology, with application in several areas to separate, concentrate or purify solutions. PSM has been justified because it is an easy-to-operate separation technique and, in general, does not involve phase change. Ceramic membranes exhibit superior properties as polymeric, mainly about chemical resistance to solvents and extremes of temperature and pH. Ceramic membranes are composed of a porous support, responsible for the mechanical resistance and covered by a thin layer, responsible for selectivity. In this work were prepared supports based on titanium oxide (TiO{sub 2}), which features high stability, thermal, chemical resistance to organic solvents and application in a wide pH range (0-14). Three aqueous solutions were prepared containing TiO{sub 2} and corn starch at concentrations of 0, 15 and 30%, acting as a pores former. The solutions were dried in Spray-Dryer, to obtain a homogeneous mixture and grainy. The support has been compressed to a pressure of 1.5 Kgfcm{sup -2} in the form of cylindrical disks of 2.5 cm diameter sintered at temperatures of 1100 and and 1150° C. The discs were weighed and their dimensions measured for the determination of geometric density and porosity. Hydraulic permeability tests were performed at pressures of 1 to 4 bar. The conditions of 1100 ° C without addition of starch and 1150 ° C with 15% of starch had porosities of 42% and 44%, respectively, values close to that suggested in the literature, between 35-40%.

  15. In vitro comparison of the biological activity of alumina ceramic and titanium particles associated with aseptic loosening

    International Nuclear Information System (INIS)

    Ding Yue; Qin Chuqiang; Xu Jie; Huang Dongsheng; Fu Yuru

    2012-01-01

    Prosthetic wear particles are thought to play a central role in the initiation and development of periprosthetic osteolysis, leading to aseptic loosening of prostheses. This study aimed to compare the biological activity of ceramic and titanium particles that are associated with particle-induced, aseptic joint loosening. Different sizes of alumina-ceramic particles and titanium particles were prepared to stimulate murine macrophage cells RAW 264.7, of which the expressions of tumor necrosis factor alpha (TNF-alpha) and receptor activator of nuclear factor-κB ligand (RANKL) were measured by qPCR and ELISA at various time points. In the presence of all particles, the expression of TNF-alpha increased in a time-dependent manner, whereas the expression of RANKL showed no regular expression patterns. Notably, particles of smaller sizes provoked significantly higher levels of TNF-alpha and RANKL than those of larger sizes. Compared to the titanium particles, the ceramic particles provoked a significantly lower production of TNF-alpha. Thus, the bioactivities of titanium and alumina ceramic particles were inversely proportional to the sizes of the particles, and the expression of RANKL was not parallel to that of TNF-alpha. The successful outcome of ceramic-on-ceramic artificial joint prostheses may be attributed to the low biological activity of ceramic particles, as evidenced here. (paper)

  16. Environmental Effects on Non-oxide Ceramics

    Science.gov (United States)

    Jacobson, Nathan S.; Opila, Elizabeth J.

    1997-01-01

    Non-oxide ceramics such as silicon carbide (SiC) and silicon nitride (Si3N4) are promising materials for a wide range of high temperature applications. These include such diverse applications as components for heat engines, high temperature electronics, and re-entry shields for space vehicles. Table I lists a number of selected applications. Most of the emphasis here will be on SiC and Si3N4. Where appropriate, other non-oxide materials such as aluminum nitride (AlN) and boron nitride (BN) will be discussed. Proposed materials include both monolithic ceramics and composites. Composites are treated in more detail elsewhere in this volume, however, many of the oxidation/corrosion reactions discussed here can be extended to composites. In application these materials will be exposed to a wide variety of environments. Table I also lists reactive components of these environments.It is well-known that SiC and Si3N4 retain their strength to high temperatures. Thus these materials have been proposed for a variety of hot-gas-path components in combustion applications. These include heat exchanger tubes, combustor liners, and porous filters for coal combustion products. All combustion gases contain CO2, CO, H2, H2O, O2, and N2. The exact gas composition is dependent on the fuel to air ratio or equivalence ratio. (Equivalence ratio (EQ) is a fuel-to-air ratio, with total hydrocarbon content normalized to the amount of O2 and defined by EQ=1 for complete combustion to CO2 and H2O). Figure 1 is a plot of equilibrium gas composition vs. equivalence ratio. Note that as a general rule, all combustion atmospheres are about 10% water vapor and 10% CO2. The amounts of CO, H2, and O2 are highly dependent on equivalence ratio.

  17. Titanium oxide nanocoating on a titanium thin film deposited on a glass substrate

    Energy Technology Data Exchange (ETDEWEB)

    Kotsedi, L., E-mail: kotsedi@tlabs.ac.za [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS, National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape (South Africa); Nuru, Z.Y. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS, National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape (South Africa); Eaton, S.M. [Physics Department, Politecnico di Milano, Piazza Leonardo Da Vinci, 32, 20133 Milano (Italy); Cummings, F.R. [University of the Western Cape, Electron Microscopy Unit, Physics Department, Bellville 7535, Cape Town (South Africa); Turco, S. Lo; Ntwaeaborwa, O.M. [Center for Nano Science and Technology, Istituto Italiano di Tecnologia, Milano, Italy Via Giovanni Pascoli, 70/3, 20133 Milano (Italy); Ramponi, R. [Institute for Photonics and Nanotechnologies (IFN)-CNR, Piazza Leonardo Da Vinci, 32, 20133 Milano (Italy); Maaza, M. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS, National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape (South Africa)

    2016-03-31

    Thin films of titanium were deposited on a glass substrate using electron beam evaporator. Femtosecond laser pulses were focused on the surface of the films, and the samples were scanned while mounted on the motorized computer-controlled motion stage to produce an areal modification of the films. X-ray diffraction of the laser-patterned samples showed evidence of the formation of a γ-Ti{sub 3}O{sub 5} with a monoclinic phase. Rutherford backscattering spectrometry simulation showed that there is an increase in the oxygen concentration as the average laser fluence is increased. Time of flight secondary ions mass spectrometry analysis showed an even distribution of the titanium and oxygen ions on the sample and also ionized molecules of the oxides of titanium were observed. The formation of the oxide of titanium was further supported using the UV–Vis-NIR spectroscopy, which showed that for 0.1 J/cm{sup 2} fluence, the laser-exposed film showed the electron transfer band and the d–d transition peak of titanium was observed at lower wavelengths. - Highlights: • γ-Ti{sub 3}O{sub 5} formed using femtosecond laser. • Fluence and oxygen relation were studied. • Nanoflakes of γ-Ti{sub 3}O{sub 5} were observed under HRSEM.

  18. Sputtered tin oxide and titanium oxide thin films as alternative transparent conductive oxides

    Energy Technology Data Exchange (ETDEWEB)

    Boltz, Janika

    2011-12-12

    Alternative transparent conductive oxides to tin doped indium oxide have been investigated. In this work, antimony doped tin oxide and niobium doped titanium oxide have been studied with the aim to prepare transparent and conductive films. Antimony doped tin oxide and niobium doped titanium oxide belong to different groups of oxides; tin oxide is a soft oxide, while titanium oxide is a hard oxide. Both oxides are isolating materials, in case the stoichiometry is SnO{sub 2} and TiO{sub 2}. In order to achieve transparent and conductive films free carriers have to be generated by oxygen vacancies, by metal ions at interstitial positions in the crystal lattice or by cation doping with Sb or Nb, respectively. Antimony doped tin oxide and niobium doped titanium oxide films have been prepared by reactive direct current magnetron sputtering (dc MS) from metallic targets. The process parameters and the doping concentration in the films have been varied. The films have been electrically, optically and structurally analysed in order to analyse the influence of the process parameters and the doping concentration on the film properties. Post-deposition treatments of the films have been performed in order to improve the film properties. For the deposition of transparent and conductive tin oxide, the dominant parameter during the deposition is the oxygen content in the sputtering gas. The Sb incorporation as doping atoms has a minor influence on the electrical, optical and structural properties. Within a narrow oxygen content in the sputtering gas highly transparent and conductive tin oxide films have been prepared. In this study, the lowest resistivity in the as deposited state is 2.9 m{omega} cm for undoped tin oxide without any postdeposition treatment. The minimum resistivity is related to a transition to crystalline films with the stoichiometry of SnO{sub 2}. At higher oxygen content the films turn out to have a higher resistivity due to an oxygen excess. After post

  19. Modification of titanium oxide membranes by Pt electrodeposition

    International Nuclear Information System (INIS)

    Avalle, L.; Santos, E.; Leiva, E.P.M.; Macagno, V.A.

    1990-01-01

    Electrochemistry techniques mainly voltamperometry and measures of impedance with titanium oxides changed by platinum atoms incorporation, were studied. This changes production some alteration in the physical chemical and electrocatalytic properties, as an example the improvement of corrosion resistance and the uses in nuclear industry. (author)

  20. Oxidation behaviour of titanium in high temperature steam

    Energy Technology Data Exchange (ETDEWEB)

    Moroishi, T; Shida, Y [Sumitomo Metal Industries Ltd., Amagasaki, Hyogo (Japan). Central Research Labs.

    1978-03-01

    The oxidation of pure titanium was studied in superheated steam at 400 -- 550/sup 0/C. The effects of prior cold working and several heat treatment conditions on the oxidation were examined and also the effects of the addition of small amounts of iron and oxygen were investigated. The oxidation mechanism of pure titanium is discussed in relation to the scale structure and the oxidation kinetics. Hydrogen absorption rate was also measured. As a result, the following conclusions were drawn: (1) The oxidation of pure titanium in steam was faster than in air and breakaway oxidation was observed above 500/sup 0/C after the specimen had gained a certain weight. Prior cold working and heat treatment conditions scarcely affected the oxidation rate, whereas the specimen containing small amounts of iron and oxygen showed a little more rapid oxidation. (2) At 500 and 550/sup 0/C a dark grey inner scale and a yellow-brown outer scale were formed. The outer scale was apt to exfoliate after the occurrence of breakaway oxidation. At 400 and 450/sup 0/C only a dark grey scale was observed. All of these oxides were identified as the rutile type, TiO/sub 2/. Furthermore, the presence of a thin and uniform oxygen rich layer beneath the external scale was confirmed at all test temperatures. (3) The measured weight gain approximately followed the cubic rate law; this would be expected for the following reason; one component of the weight gain is due to the dissolved oxygen, the amount of which remains constant after the early stages of oxidation. The second component is due to the parabolic growth of the external TiO/sub 2/ scale. When these contributions are added a pseudo-cubic weight gain curve results. (4) It was shown that 50 percent of the hydrogen generated during the oxidation was absorbed into the metal.

  1. Oxidation behaviour of titanium in high temperature steam

    International Nuclear Information System (INIS)

    Moroishi, Taishi; Shida, Yoshiaki

    1978-01-01

    The oxidation of pure titanium was studied in superheated steam at 400 -- 550 0 C. The effects of prior cold working and several heat treatment conditions on the oxidation were examined and also the effects of the addition of small amounts of iron and oxygen were investigated. The oxidation mechanism of pure titanium is discussed in relation to the scale structure and the oxidation kinetics. Hydrogen absorption rate was also measured. As a result, the following conclusions were drawn: (1) The oxidation of pure titanium in steam was faster than in air and breakaway oxidation was observed above 500 0 C after the specimen had gained a certain weight. Prior cold working and heat treatment conditions scarcely affected the oxidation rate, whereas the specimen containing small amounts of iron and oxygen showed a little more rapid oxidation. (2) At 500 and 550 0 C a dark grey inner scale and a yellow-brown outer scale were formed. The outer scale was apt to exfoliate after the occurrence of breakaway oxidation. At 400 and 450 0 C only a dark grey scale was observed. All of these oxides were identified as the rutile type, TiO 2 . Furthermore, the presence of a thin and uniform oxygen rich layer beneath the external scale was confirmed at all test temperatures. (3) The measured weight gain approximately followed the cubic rate law; this would be expected for the following reason; one component of the weight gain is due to the dissolved oxygen, the amount of which remains constant after the early stages of oxidation. The second component is due to the parabolic growth of the external TiO 2 scale. When these contributions are added a pseudo-cubic weight gain curve results. (4) It was shown that 50 percent of the hydrogen generated during the oxidation was absorbed into the metal. (auth.)

  2. Boric oxide or boric acid sintering aid for sintering ceramics

    International Nuclear Information System (INIS)

    Lawler, H.A.

    1979-01-01

    The invention described relates to the use of liquid sintering aid in processes involving sintering of ceramic materials to produce dense, hard articles having industrial uses. Although the invention is specifically discussed in regard to compositions containing silicon carbide as the ceramic material, other sinterable carbides, for example, titanium carbide, may be utilized as the ceramic material. A liquid sintering aid for densifying ceramic material is selected from solutions of H 3 BO 3 , B 2 O 3 and mixtures of these solutions. In sintering ceramic articles, e.g. silicon carbide, a shaped green body is formed from a particulate ceramic material and a resin binder, and the green body is baked at a temperature of 500 to 1000 0 C to form a porous body. The liquid sintering aid of B 2 O 3 and/or H 3 BO 3 is then dispersed through the porous body and the treated body is sintered at a temperature of 1900 to 2200 0 C to produce the sintered ceramic article. (U.K.)

  3. Attachment and growth behaviour of human gingival fibroblasts on titanium and zirconia ceramic surfaces

    International Nuclear Information System (INIS)

    Pae, Ahran; Kim, Hyeong-Seob; Woo, Yi-Hyung; Lee, Heesu; Kwon, Yong-Dae

    2009-01-01

    The attachment, growth behaviour and the genetic effect of human gingival fibroblasts (HGF) cultured on titanium and different zirconia surfaces were investigated. HGF cells were cultured on (1) titanium discs with a machined surface, (2) yttrium-stabilized tetragonal zirconia polycrystals (Y-TZP) with a smooth surface and (3) Y-TZP with 100 μm grooves. The cell proliferation activity was evaluated through a MTT assay at 24 h and 48 h, and the cell morphology was examined by SEM. The mRNA expression of integrin-β1, type I and III collagen, laminin and fibronectin in HGF were evaluated by RT-PCR after 24 h. From the MTT assay, the mean optical density values for the titanium and grooved zirconia surfaces after 48 h of HGF adhesion were greater than the values obtained for the smooth zirconia surfaces. SEM images showed that more cells were attached to the grooves, and the cells appeared to follow the direction of the grooves. The results of RT-PCR suggest that all groups showed comparable fibroblast-specific gene expression. A zirconia ceramic surface with grooves showed biological responses that were comparable to those obtained with HGF on a titanium surface.

  4. MHD oxidant intermediate temperature ceramic heater study

    Science.gov (United States)

    Carlson, A. W.; Chait, I. L.; Saari, D. P.; Marksberry, C. L.

    1981-09-01

    The use of three types of directly fired ceramic heaters for preheating oxygen enriched air to an intermediate temperature of 1144K was investigated. The three types of ceramic heaters are: (1) a fixed bed, periodic flow ceramic brick regenerative heater; (2) a ceramic pebble regenerative heater. The heater design, performance and operating characteristics under conditions in which the particulate matter is not solidified are evaluated. A comparison and overall evaluation of the three types of ceramic heaters and temperature range determination at which the particulate matter in the MHD exhaust gas is estimated to be a dry powder are presented.

  5. The temperature dependence of thermooptical properties of magnetooptical TAG ceramics doped with silicon and titanium

    Science.gov (United States)

    Starobor, Aleksey; Palashov, Oleg

    2018-04-01

    Thermal effects in terbium aluminum garnet (TAG) ceramics (thermal lens and thermally induced depolarization) doped with silicon and titanium were investigated in temperature range of 79-293K. Samples with low dopant concentrations shows decreasing of negative thermal effects with cooling to 79 K. However for most part of samples thermal depolarization starts increasing after initial decreasing with cooling. Apparently it is connected with defects in media. Best sample (0.4 at% of Si) as pure TAG shows monotonous decreasing of thermally induced depolarization and 3.5 times Verdet constant increasing with cooling to 79 K, that leads to 1.8-times advantage over common magnetooptical media - terbium gallium garnet. It allows to provide an isolation of 30 dB at a radiation power of more than 6 kW as estimated. However, the procedure for creating ceramics samples obviously needs improvement because of the large scatter in the quality of the samples.

  6. Carbon nanotube-based coatings on titanium

    Indian Academy of Sciences (India)

    Administrator

    mon method is the deposition of bioactive ceramic mate- rials on the metal ... tion of nanoparticle layer, including carbon nanoparti- ... Coatings made of CNTs provide implants with .... reaches composite of CNT built into titanium oxide formed.

  7. Study on Microstructures and Mechanical Properties of Foam Titanium Carbide Ceramics Fabricated by Reaction Sintering Process

    Science.gov (United States)

    Ma, Yana; Bao, Chonggao; Chen, Jie; Song, Suocheng; Han, Longhao

    2018-05-01

    Foam titanium carbide (TiC) ceramics with a three-dimensional network structure were fabricated by the reaction sintering process, in which polyurethane foam was taken as the template, and TiO2 and phenolic resin were used as the reactants. Phase, microstructures and fracture morphologies of foam TiC ceramics were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The results show that when the mass ratios of phenolic resin and TiO2 (F/T) are (0.8-1.2): 1, foam TiC ceramics with pure TiC phase can be formed. As the F/T ratios increase, crystal lattice parameters of fabricated foam TiC ceramics become bigger. When the value of F/T decreases from 1.2 to 0.8, grain size of TiC grows larger and microstructures get denser; meanwhile, the compressive strength increases from 0.10 to 1.05 MPa. Additionally, either raising the sintering temperatures or extending holding time can facilitate the completion of the reaction process and increase the compressive strength.

  8. Synthesis and characterization of ceramic pigments based on oxides of chromium and iron, on TiO2

    International Nuclear Information System (INIS)

    Silva, E.M. da; Galvao, S.B.; Paskocimas, C.A.

    2011-01-01

    This work used oxides of chromium and iron, as precursors of the synthesis of ceramic pigments. The synthesis is based on the dissolution of citric acid as a complexing agent, addition of metal oxides, such as ion chromophores; polymerization with ethylene glycol and doping with titanium oxide. Passing through pre-calcination, breakdown, calcination at different temperatures (900 and 1100 ° C), resulting in pigments: green for pigment chrome deposited on TiO 2 and orange for iron on TiO 2 . Noticing an increase in the opacity with increasing temperature. The thermal analysis (TG and DTA), evaluated their thermal behavior, the XRD revealed the formation of crystalline phases as Iron Titanate and Chrome Titanate; SEM showed the formation of hexagonal particles for both oxides. Thus, the synthesized oxides were within the requirements for application as ceramic pigments. (author)

  9. Waste conversion into high-value ceramics: Carbothermal nitridation synthesis of titanium nitride nanoparticles using automotive shredder waste.

    Science.gov (United States)

    Mayyas, Mohannad; Pahlevani, Farshid; Maroufi, Samane; Liu, Zhao; Sahajwalla, Veena

    2017-03-01

    Environmental concern about automotive shredder residue (ASR) has increased in recent years due to its harmful content of heavy metals. Although several approaches of ASR management have been suggested, these approaches remain commercially unproven. This study presents an alternative approach for ASR management where advanced materials can be generated as a by-product. In this approach, titanium nitride (TiN) has been thermally synthesized by nitriding pressed mixture of automotive shredder residue (ASR) and titanium oxide (TiO 2 ). Interactions between TiO 2 and ASR at non-isothermal conditions were primarily investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry. Results indicated that TiO 2 influences and catalyses degradation reactions of ASR, and the temperature, at which reduction starts, was determined around 980 °C. The interaction between TiO 2 and ASR at isothermal conditions in the temperature range between 1200 and 1550 °C was also studied. The pressed mixture of both materials resulted in titanium nitride (TiN) ceramic at all given temperatures. Formation kinetics were extracted using several models for product layer diffusion-controlled solid-solid and solid-fluid reactions. The effect of reactants ratio and temperature on the degree of conversion and morphology was investigated. The effect of reactants ratio was found to have considerable effect on the morphology of the resulting material, while temperature had a lesser impact. Several unique structures of TiN (porous nanostructured, polycrystalline, micro-spherical and nano-sized structures) were obtained by simply tuning the ratio of TiO 2 to ASR, and a product with appreciable TiN content of around 85% was achieved after only one hour nitridation at 1550 °C. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Fracture Resistance and Mode of Failure of Ceramic versus Titanium Implant Abutments and Single Implant-Supported Restorations.

    Science.gov (United States)

    Sghaireen, Mohd G

    2015-06-01

    The material of choice for implant-supported restorations is affected by esthetic requirements and type of abutment. This study compares the fracture resistance of different types of implant abutments and implant-supported restorations and their mode of failure. Forty-five Oraltronics Pitt-Easy implants (Oraltronics Dental Implant Technology GmbH, Bremen, Germany) (4 mm diameter, 10 mm length) were embedded in clear autopolymerizing acrylic resin. The implants were randomly divided into three groups, A, B and C, of 15 implants each. In group A, titanium abutments and metal-ceramic crowns were used. In group B, zirconia ceramic abutments and In-Ceram Alumina crowns were used. In group C, zirconia ceramic abutments and IPS Empress Esthetic crowns were used. Specimens were tested to failure by applying load at 130° from horizontal plane using an Instron Universal Testing Machine. Subsequently, the mode of failure of each specimen was identified. Fracture resistance was significantly different between groups (p Empress crowns supported by zirconia abutments had the lowest fracture loads (p = .000). Fracture modes of metal-ceramic crowns supported by titanium abutments included screw fracture and screw bending. Fracture of both crown and abutment was the dominant mode of failure of In-Ceram/IPS Empress crowns supported by zirconia abutments. Metal-ceramic crowns supported by titanium abutments were more resistant to fracture than In-Ceram crowns supported by zirconia abutments, which in turn were more resistant to fracture than IPS Empress crowns supported by zirconia abutments. In addition, failure modes of restorations supported by zirconia abutments were more catastrophic than those for restorations supported by titanium abutments. © 2013 Wiley Periodicals, Inc.

  11. Narrow titanium oxide nanowires induced by femtosecond laser pulses on a titanium surface

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hui; Li, Xian-Feng [Laboratory of Nanophotonic Functional Materials and Devices, School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006 (China); Zhang, Cheng-Yun [School of Physics and Electronic Engineering, Guangzhou University, Guangzhou 510006 (China); Tie, Shao-Long [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Lan, Sheng, E-mail: slan@scnu.edu.cn [Laboratory of Nanophotonic Functional Materials and Devices, School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006 (China)

    2017-02-28

    Highlights: • Titanium oxide nanowires with a feature width as narrow as ∼20 nm were induced on a titanium surface by using femtosecond laser pulses at 400 nm. • An evolution of the surface structure from a high spatial frequency laser-induced periodic structure parallel to the laser polarization to a low spatial frequency one perpendicular to the laser polarization was observed with increasing irradiation pulse number. • The formation of the titanium oxide nanowires was confirmed by the energy dispersive spectroscopy measurements and the evolution of the surface structure was successfully interpreted by using the efficacy factor theory. - Abstract: The evolution of the nanostructure induced on a titanium (Ti) surface with increasing irradiation pulse number by using a 400-nm femtosecond laser was examined by using scanning electron microscopy. High spatial frequency periodic structures of TiO{sub 2} parallel to the laser polarization were initially observed because of the laser-induced oxidation of the Ti surface and the larger efficacy factor of TiO{sub 2} in this direction. Periodically aligned TiO{sub 2} nanowires with featured width as small as 20 nm were obtained. With increasing pulse number, however, low spatial frequency periodic structures of Ti perpendicular to the laser polarization became dominant because Ti possesses a larger efficacy factor in this direction. The competition between the high- and low-spatial frequency periodic structures is in good agreement with the prediction of the efficacy factor theory and it should also be observed in the femtosecond laser ablation of other metals which are easily oxidized in air.

  12. Molecular and physiological responses to titanium dioxide and cerium oxide nanoparticles in Arabidopsis

    Science.gov (United States)

    - Changes in tissue transcriptomes and productivity of Arabidopsis thaliana were investigated during exposure of plants to two widely-used engineered metal oxide nanoparticles, titanium dioxide (nano-titanium) and cerium dioxide (nano-cerium). Microarray analyses confirmed that e...

  13. Ultrahighly Dispersed Titanium Oxide on Silica : Effect of Precursors on the Structure and Photocatalysis

    OpenAIRE

    Yoshida , S.; Takenaka , S.; Tanaka , T.; Funabiki , T.

    1997-01-01

    The effect of precursor on the dispersion and catalytic performance of titanium oxide supported on silica has ben investigated. The catalysts were prepared by a simple impregnation method with three kinds of titanium complexes of different ligands (bis(isopropyato)-bis(pivaroylmethanato) : DPM, acetylacetonato : ACAC, tetrakis(isopropylato) : IPRO) with the aim of preparing ultrahighly dispersed titanium oxide on silica. The XAFS study revealed that titanium species in the catalyst prepared f...

  14. Improving tribological and anti-bacterial properties of titanium external fixation pins through surface ceramic conversion.

    Science.gov (United States)

    Dong, Huan; Mukinay, Tatiana; Li, Maojun; Hood, Richard; Soo, Sein Leung; Cockshott, Simon; Sammons, Rachel; Li, Xiaoying

    2017-01-01

    In this study, an advanced ceramic conversion surface engineering technology has been applied for the first time to self-drilling Ti6Al4V external fixation pins to improve their performance in terms of biomechanical, bio-tribological and antibacterial properties. Systematic characterisation of the ceramic conversion treated Ti pins was carried out using Scanning electron microscope, X-ray diffraction, Glow-discharge optical emission spectroscopy, nano- and micro-indentation and scratching; the biomechanical and bio-tribological properties of the surface engineered Ti pins were evaluated by insertion into high density bone simulation material; and the antibacterial behaviour was assessed with Staphylococcus aureus NCTC 6571. The experimental results have demonstrated that the surfaces of Ti6Al4V external fixation pins were successfully converted into a TiO 2 rutile layer (~2 μm in thickness) supported by an oxygen hardened case (~15 μm in thickness) with very good bonding due to the in-situ conversion nature. The maximum insertion force and temperature were reduced from 192N and 31.2 °C when using the untreated pins to 182N and 26.1 °C when the ceramic conversion treated pins were tested. This is mainly due to the significantly increased hardness (more than three times) and the effectively enhanced wear resistance of the cutting edge of the self-drilling Ti pins following the ceramic conversion treatment. The antibacterial tests also revealed that there was a significantly reduced number of bacteria isolated from the ceramic conversion treated pins compared to the untreated pins of around 50 % after 20 h incubation, P < 0.01 (0.0024). The results reported are encouraging and could pave the way towards high-performance anti-bacterial titanium external fixation pins with reduced pin-track infection and pin loosing.

  15. Thermal expansion and microstructural analysis of experimental metal-ceramic titanium alloys.

    Science.gov (United States)

    Zinelis, Spiros; Tsetsekou, Athena; Papadopoulos, Triantafillos

    2003-10-01

    Statement of problem Low-fusing porcelains for titanium veneering have demonstrated inferior color stability and metal-ceramic longevity compared to conventional porcelains. This study evaluated the microstructure and thermal expansion coefficients of some experimental titanium alloys as alternative metallic substrates for low-fusing conventional porcelain. Commercially pure titanium (CP Ti) and various metallic elements (Al, Co, Sn, Ga, In, Mn) were used to prepare 8 titanium alloys using a commercial 2-chamber electric-arc vacuum/inert gas dental casting machine (Cyclarc). The nominal compositions of these alloys were the following (wt%): I: 80Ti-18Sn-1.5In-0.5Mn; II: 76Ti-12Ga-7Sn-4Al-1Co; III: 87Ti-13Ga; IV: 79Ti-13Ga-7Al-1Co; V: 82Ti-18In; VI: 75.5Ti-18In-5Al-1Co-0.5Mn; VII: 85Ti-10Sn-5Al; VIII: 78Ti-12Co-7Ga-3Sn. Six rectangular wax patterns for each test material (l = 25 mm, w = 3 mm, h = 1 mm) were invested with magnesia-based material and cast with grade II CP Ti (control) and the 8 experimental alloys. The porosity of each casting was evaluated radiographically, and defective specimens were discarded. Two cast specimens from CP Ti and alloys I-VIII were embedded in epoxy resin and, after metallographic grinding and polishing, were studied by means of scanning electron microscopy and wavelength dispersive electron probe microanalysis. One specimen of each material was utilized for the determination of coefficient of thermal expansion (CTE) with a dilatometer operating from room temperature up to 650 degrees C at a heating rate of 5 degrees C/minute. Secondary electron images (SEI) and compositional backscattered electron images (BEI-COMPO) revealed that all cast specimens consisted of a homogeneous matrix except Alloy VIII, which contained a second phase (possibly Ti(2)Co) along with the titanium matrix. The results showed that the coefficient of thermal expansion (CTE) varied from 10.1 to 13.1 x 10(-6)/ degrees C (25 degrees -500 degrees C), depending on

  16. Titanium oxide nanoparticles as additives in engine oil

    Directory of Open Access Journals (Sweden)

    Meena Laad

    2018-04-01

    Full Text Available This research study investigates the tribological behaviour of titanium oxide (TiO2 nanoparticles as additives in mineral based multi-grade engine oil. All tests were performed under variable load and varying concentrations of nanoparticles in lubricating oil. The friction and wear experiments were performed using pin-on-disc tribotester. This study shows that mixing of TiO2 nanoparticles in engine oil significantly reduces the friction and wear rate and hence improves the lubricating properties of engine oil. The dispersion analysis of TiO2 nanoparticles in lubricating oil using UV spectrometer confirms that TiO2 nanoparticles possess good stability and solubility in the lubricant and improve the lubricating properties of the engine oil. Keywords: Titanium oxide, Nanoparticles, UV spectrometer, Tribotester, Engine oil

  17. Planar ceramic membrane assembly and oxidation reactor system

    Science.gov (United States)

    Carolan, Michael Francis; Dyer, legal representative, Kathryn Beverly; Wilson, Merrill Anderson; Ohm, Ted R.; Kneidel, Kurt E.; Peterson, David; Chen, Christopher M.; Rackers, Keith Gerard; Dyer, deceased, Paul Nigel

    2007-10-09

    Planar ceramic membrane assembly comprising a dense layer of mixed-conducting multi-component metal oxide material, wherein the dense layer has a first side and a second side, a porous layer of mixed-conducting multi-component metal oxide material in contact with the first side of the dense layer, and a ceramic channeled support layer in contact with the second side of the dense layer. The planar ceramic membrane assembly can be used in a ceramic wafer assembly comprising a planar ceramic channeled support layer having a first side and a second side; a first dense layer of mixed-conducting multi-component metal oxide material having an inner side and an outer side, wherein the inner side is in contact with the first side of the ceramic channeled support layer; a first outer support layer comprising porous mixed-conducting multi-component metal oxide material and having an inner side and an outer side, wherein the inner side is in contact with the outer side of the first dense layer; a second dense layer of mixed-conducting multi-component metal oxide material having an inner side and an outer side, wherein the inner side is in contact with the second side of the ceramic channeled layer; and a second outer support layer comprising porous mixed-conducting multi-component metal oxide material and having an inner side and an outer side, wherein the inner side is in contact with the outer side of the second dense layer.

  18. Processing of pure titanium containing titanium-based reinforcing ceramics additives using spark plasma sintering

    Directory of Open Access Journals (Sweden)

    Mondiu Olayinka DUROWOJU

    2017-06-01

    Full Text Available The densification behaviour, microstructural changes and hardness characteristics during spark plasma sintering of CP-Ti reinforced with TiC, TiN, TiCN and TiB2 were investigated. Commercially pure Ti powders were dry mixed with varied amounts (2.5 and 5 wt. % of the ceramic additives using a T2F Turbula mixer for 5 h and at a speed of 49 rpm. The blended composite powders were then sintered using spark plasma sintering system (model HHPD-25 from FCT Germany at a heating rate of 100oC min-1, dwell time of 5 min and sintering temperature of 950ºC. The sintering of CP-Ti was used as a base study to select the proper spark plasma sintering temperature for full density. Densification was monitored through analysis of the recorded punch displacement and the measured density of the sintered samples using Archimedes method. High densities ranging from 97.8% for 5% TiB2 addition to 99.6% for 5% TiCN addition were achieved at a relatively low temperature of 950°C. Microstructural analyses show a uniform distribution of the additives and finer structure showing their inhibitive effect on grain growth. An improved hardness was observed in all the cases with highest values obtained with TiCN as a result of the combined effect of TiC and TiN. A change in the fracture mode from trans granular to intergranular was also observed.

  19. Effect of hot pressing additives on the leachability of hot pressed sodium hydrous titanium oxide

    International Nuclear Information System (INIS)

    Valentine, T.M.; Sambell, R.A.J.

    1980-01-01

    Sodium hydrous titanium oxide is an ion exchange resin which can be used for immobilizing medium level waste (MLW) liquors. When hot pressed, it undergoes conversion to a ceramic. Three low melting point materials (borax, bismuth trioxide, and a mixture of PbO/CuO) were added to the (Na)HTiO and the effect that each of these had on aiding densification was assessed. Hot pressing temperature, applied pressure, and percentage addition of hot pressing aid were varied. Percentage open porosity, flexural strength, and leachability were measured. There was a linear relationship between the percentage open porosity and the logarithm of the leach rate for a constant percentage addition of each additive

  20. Polypyrrole/titanium oxide nanotube arrays composites as an active material for supercapacitors.

    Science.gov (United States)

    Kim, Min Seok; Park, Jong Hyeok

    2011-05-01

    The authors present the first reported use of vertically oriented titanium oxide nanotube/polypyrrole (PPy) nanocomposites to increase the specific capacitance of TiO2 based energy storage devices. To increase their electrical storage capacity, titanium oxide nanotubes were coated with PPy and their morphologies were characterized. The incorporation of PPy increased the specific capacitance of the titanium oxide nanotube based supercapacitor system, due to their increased surface area and additional pseudo-capacitance.

  1. Nonstoichiometric Titanium Oxides via Pulsed Laser Ablation in Water

    Directory of Open Access Journals (Sweden)

    Chen Shuei-Yuan

    2010-01-01

    Full Text Available Abstract Titanium oxide compounds TiO,Ti2O3, and TiO2 with a considerable extent of nonstoichiometry were fabricated by pulsed laser ablation in water and characterized by X-ray/electron diffraction, X-ray photoelectron spectroscopy and electron energy loss spectroscopy. The titanium oxides were found to occur as nanoparticle aggregates with a predominant 3+ charge and amorphous microtubes when fabricated under an average power density of ca. 1 × 108W/cm2 and 1011W/cm2, respectively followed by dwelling in water. The crystalline colloidal particles have a relatively high content of Ti2+ and hence a lower minimum band gap of 3.4 eV in comparison with 5.2 eV for the amorphous state. The protonation on both crystalline and amorphous phase caused defects, mainly titanium rather than oxygen vacancies and charge and/or volume-compensating defects. The hydrophilic nature and presumably varied extent of undercoordination at the free surface of the amorphous lamellae accounts for their rolling as tubes at water/air and water/glass interfaces. The nonstoichiometric titania thus fabricated have potential optoelectronic and catalytic applications in UV–visible range and shed light on the Ti charge and phase behavior of titania-water binary in natural shock occurrence.

  2. Self-cleaning glass coating containing titanium oxide and silicon

    International Nuclear Information System (INIS)

    Araujo, A.O. de; Alves, A.K.; Berutti, F.A.; Bergmann, C.P.

    2009-01-01

    Using the electro spinning technique nano fibers of titanium oxide doped with silicon were synthesized. As precursor materials, titanium propoxide, silicon tetra propoxide and a solution of polyvinylpyrrolidone were used. The non-tissue material obtained was characterized by X-ray diffraction to determine the phase and crystallite size, BET method to determine the surface and SEM to analyze the microstructure of the fibers. After ultrasound dispersion of this material in ethanol, the glass coatings were made by dip-coating methodology. The influence of the removal velocity, the solution composition and the glass surface preparation were evaluated. The film was characterized by the contact angle of a water droplet in its surface. (author)

  3. Self-cleaning glasses containing nanostructured titanium oxide

    International Nuclear Information System (INIS)

    Araujo, A.; Alves, A.K.; Berutti, F.A.; Bergmann, C.P.

    2010-01-01

    Using the electrospinning technique nanofibers of titanium oxide were synthesized. As precursor materials, titanium propoxide and a solution of polyvinylpyrrolidone were used. After the electrospinning process, the non-tissue material obtained was heat treated and characterized by X-ray diffraction to determine the phase crystallinity, and SEM to analyze the microstructure of the fibers. After ultrasound dispersion of this material in isopropyl alcohol, the glass coatings were made by dip-coating methodology. The removal velocity was kept constant, but the solution composition was varied to obtain a transparent and photo active film. The film was characterized by the contact angle of a water droplet in its surface (hydrophilicity), the transparency was evaluated using a spectrophotometer and the photocatalytic activity of the film was also evaluated. (author)

  4. Cathodic arc sputtering of functional titanium oxide thin films, demonstrating resistive switching

    Energy Technology Data Exchange (ETDEWEB)

    Shvets, Petr, E-mail: pshvets@innopark.kantiana.ru; Maksimova, Ksenia; Demin, Maxim; Dikaya, Olga; Goikhman, Alexander

    2017-05-15

    The formation of thin films of the different stable and metastable titanium oxide phases is demonstrated by cathode arc sputtering of a titanium target in an oxygen atmosphere. We also show that sputtering of titanium in vacuum yields the formation of titanium silicides on the silicon substrate. The crystal structure of the produced samples was investigated using Raman spectroscopy and X-ray diffraction. We conclude that cathode arc sputtering is a flexible method suitable for producing the functional films for electronic applications. The functionality is verified by the memory effect demonstration, based on the resistive switching in the titanium oxide thin film structure.

  5. Development of Bioactive Ceramic Coating on Titanium Alloy substrate for Biomedical Application Using Dip Coating Method

    Science.gov (United States)

    Asmawi, R.; Ibrahim, M. H. I.; Amin, A. M.; Mustafa, N.; Noranai, Z.

    2017-08-01

    Bioactive apatite, such as hydroxyapatite ceramic (HA), [Ca10(PO4)6(OH)2] has been extensively investigated for biomedical applications due to its excellent biocompatibility and tissue bioactivity properties. Its bioactivity provides direct bonding to the bone tissue. Because of its similarity in chemical composition to the inorganic matrix of bone, HA is widely used as implant materials for bone. Unfortunately, because of its poor mechanical properties,. this bioactive material is not suitable for load bearing applications. In this study, by the assistance of dip-coating technique, HA coatings were deposited on titanium alloy substrates by employing hydrothermal derived HA powder. The produced coatings then were oven-dried at 130°C for 1 hour and calcined at various temperature over the range of 200-800°C for 1 hour. XRD measurement showed that HA was the only phase present in the coatings. However coatings calcined at 800°C comprised a mixture of HA and tri-calcium phosphate (TCP). FTIR measurement showed the existence of hydroxyl, phosphate, and carbonate bands. PO4 - band became sharper and narrower with the increased of calcination temperature. FESEM observation showed that the coating is polycrystalline with individual particles of nano to submicron size and has an average particle size of 35 nm. The thickness of the coating are direcly propotional with the viscosity of coating slurry. It was shown that the more viscous coating slurry would produce a thicker ceramic coating. Mechanical properties of the coating were measured in term of adhesion strength using a Micro Materials Nano Test microscratch testing machine. The result revealed that the coating had a good adhesion to the titanium alloy substrate.

  6. Synthesis and characterization of titanium oxide supported silica materials

    Science.gov (United States)

    Schrijnemakers, Koen

    2002-01-01

    Titania-silica materials are interesting materials for use in catalysis, both as a catalyst support as well as a catalyst itself. Titania-silica materials combine the excellent support and photocatalytic properties of titania with the high thermal and mechanical stability of silica. Moreover, the interaction of titania with silica leads to new active sites, such as acid and redox sites, that are not found on the single oxides. In this Ph.D. two recently developed deposition methods were studied and evaluated for their use to create titanium oxide supported silica materials, the Chemical Surface Coating (CSC) and the Molecular Designed Dispersion (MDD). These methods were applied to two structurally different silica supports, an amorphous silica gel and the highly ordered MCM-48. Both methods are based on the specific interaction between a titanium source and the functional groups on the silica surface. With the CSC method high amounts of titanium can be obtained. However, clustering of the titania phase is observed in most cases. The MDD method allows much lower titanium amounts to be deposited without the formation of crystallites. Only at the highest Ti loading very small crystallites are formed after calcination. MCM-48 and silica gel are both pure SiO2 materials and therefore chemically similar to each other. However, they possess a different morphology and are synthesized in a different way. As such, some authors have reported that the MCM-48 surface would be more reactive than the surface of silica gel. In our experiments however no differences could be observed that confirmed this hypothesis. In the CSC method, the same reactions were observed and similar amounts of Ti and Cl were deposited. In the case of the MDD method, no difference in the reaction mechanism was observed. However, due to the lower thermal and hydrothermal stability of the MCM-48 structure compared to silica gel, partial incorporation of Ti atoms in the pore walls of MCM-48 took place

  7. Oxidative dehydrogenation of isobutane over a titanium pyrophosphate catalyst

    Directory of Open Access Journals (Sweden)

    IOAN-CEZAR MARCU

    2005-06-01

    Full Text Available The catalytic properties of titanium pyrophosphate in the oxidative dehydrogenation of isobutane to isobutylene were investigated in the 400 – 550 ºC temperature range. Asignificant change of the product distribution and of the apparent activation energy of the reactionwas observed at about 490 ºC. This phenomenon, already observed in the oxidative dehydrogenation of n-butane, has been interpreted by the existence of two reaction mechanisms depending upon the reaction temperature. Comparison with the n-butane reaction allowed different activation pathways for the activation of alkanes to be proposed. The catalytic properties of TiP2O7 in the oxidative dehydrogenation of isobutane was also compared to those obtained previously with several other pyrophosphates and TiP2O7 was found to be less active and selective for this reaction.

  8. Titanium

    DEFF Research Database (Denmark)

    Fage, Simon W; Muris, Joris; Jakobsen, Stig S

    2016-01-01

    Exposure to titanium (Ti) from implants and from personal care products as nanoparticles (NPs) is common. This article reviews exposure sources, ion release, skin penetration, allergenic effects, and diagnostic possibilities. We conclude that human exposure to Ti mainly derives from dental...... and medical implants, personal care products, and foods. Despite being considered to be highly biocompatible relative to other metals, Ti is released in the presence of biological fluids and tissue, especially under certain circumstances, which seem to be more likely with regard to dental implants. Although...... most of the studies reviewed have important limitations, Ti seems not to penetrate a competent skin barrier, either as pure Ti, alloy, or as Ti oxide NPs. However, there are some indications of Ti penetration through the oral mucosa. We conclude that patch testing with the available Ti preparations...

  9. Guided self-assembly of nanostructured titanium oxide

    International Nuclear Information System (INIS)

    Wang Baoxiang; Rozynek, Zbigniew; Fossum, Jon Otto; Knudsen, Kenneth D; Yu Yingda

    2012-01-01

    A series of nanostructured titanium oxide particles were synthesized by a simple wet chemical method and characterized by means of small-angle x-ray scattering (SAXS)/wide-angle x-ray scattering (WAXS), atomic force microscope (AFM), scanning electron microscope (SEM), transmission electron microscope (TEM), thermal analysis, and rheometry. Tetrabutyl titanate (TBT) and ethylene glycol (EG) can be combined to form either TiO x nanowires or smooth nanorods, and the molar ratio of TBT:EG determines which of these is obtained. Therefore, TiO x nanorods with a highly rough surface can be obtained by hydrolysis of TBT with the addition of cetyl-trimethyl-ammonium bromide (CTAB) as surfactant in an EG solution. Furthermore, TiO x nanorods with two sharp ends can be obtained by hydrolysis of TBT with the addition of salt (LiCl) in an EG solution. The AFM results show that the TiO x nanorods with rough surfaces are formed by the self-assembly of TiO x nanospheres. The electrorheological (ER) effect was investigated using a suspension of titanium oxide nanowires or nanorods dispersed in silicone oil. Oil suspensions of titanium oxide nanowires or nanorods exhibit a dramatic reorganization when submitted to a strong DC electric field and the particles aggregate to form chain-like structures along the direction of applied electric field. Two-dimensional SAXS images from chains of anisotropically shaped particles exhibit a marked asymmetry in the SAXS patterns, reflecting the preferential self-assembly of the particles in the field. The suspension of rough TiO x nanorods shows stronger ER properties than that of the other nanostructured TiO x particles. We find that the particle surface roughness plays an important role in modification of the dielectric properties and in the enhancement of the ER effect. (paper)

  10. Guided self-assembly of nanostructured titanium oxide

    Science.gov (United States)

    Wang, Baoxiang; Rozynek, Zbigniew; Fossum, Jon Otto; Knudsen, Kenneth D.; Yu, Yingda

    2012-02-01

    A series of nanostructured titanium oxide particles were synthesized by a simple wet chemical method and characterized by means of small-angle x-ray scattering (SAXS)/wide-angle x-ray scattering (WAXS), atomic force microscope (AFM), scanning electron microscope (SEM), transmission electron microscope (TEM), thermal analysis, and rheometry. Tetrabutyl titanate (TBT) and ethylene glycol (EG) can be combined to form either TiOx nanowires or smooth nanorods, and the molar ratio of TBT:EG determines which of these is obtained. Therefore, TiOx nanorods with a highly rough surface can be obtained by hydrolysis of TBT with the addition of cetyl-trimethyl-ammonium bromide (CTAB) as surfactant in an EG solution. Furthermore, TiOx nanorods with two sharp ends can be obtained by hydrolysis of TBT with the addition of salt (LiCl) in an EG solution. The AFM results show that the TiOx nanorods with rough surfaces are formed by the self-assembly of TiOx nanospheres. The electrorheological (ER) effect was investigated using a suspension of titanium oxide nanowires or nanorods dispersed in silicone oil. Oil suspensions of titanium oxide nanowires or nanorods exhibit a dramatic reorganization when submitted to a strong DC electric field and the particles aggregate to form chain-like structures along the direction of applied electric field. Two-dimensional SAXS images from chains of anisotropically shaped particles exhibit a marked asymmetry in the SAXS patterns, reflecting the preferential self-assembly of the particles in the field. The suspension of rough TiOx nanorods shows stronger ER properties than that of the other nanostructured TiOx particles. We find that the particle surface roughness plays an important role in modification of the dielectric properties and in the enhancement of the ER effect.

  11. Oxidation resistant filler metals for direct brazing of structural ceramics

    Science.gov (United States)

    Moorhead, Arthur J.

    1986-01-01

    A method of joining ceramics and metals to themselves and to one another is described using essentially pure trinickel aluminide and trinickel aluminide containing small amounts of carbon. This method produces strong joints that can withstand high service temperatures and oxidizing environments.

  12. Compatibility of sodium with ceramic oxides employed in nuclear reactors

    International Nuclear Information System (INIS)

    Acena, V.

    1981-01-01

    A review of experiments carried out up to the present time on the corrosion and compatibility of ceramic oxides with liquid sodium at temperatures corresponding to those in fast breeder reactors, is presented. The results of a thermo-dynamic/liquid sodium reactions are included. The exercise has been conducted with a view to effecting experimental studies in the future. (author) [es

  13. Compatibility of sodium with ceramic oxides employed in nuclear reactors

    International Nuclear Information System (INIS)

    Acena Moreno, V.

    1981-01-01

    This work is a review of experiments carried out up to the present time on the corrosion and compatibility of ceramic oxides with liquid sodium at temperatures corresponding to those in fast breeder reactors. The review also includes the results of a thermo-dynamic/liquid sodium reactions. The exercise has been conducted with a view to effecting experimental studies in the future. (Author)

  14. Highly porous ceramic oxide aerogels having improved flexibility

    Science.gov (United States)

    Meador, Mary Ann B. (Inventor); Nguyen, Baochau N. (Inventor); Guo, Haiquan (Inventor)

    2012-01-01

    Ceramic oxide aerogels having improved flexibility are disclosed. Preferred embodiments exhibit high modulus and other strength properties despite their improved flexibility. The gels may be polymer cross-linked via organic polymer chains to further improve strength properties, without substantially detracting from the improved flexibility. Methods of making such aerogels are also disclosed.

  15. The radiolysis of lithium oxide ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Tiliks, J; Supe, A; Kizane, G; Tiliks, J Jr [Latvia Univ., Riga (Latvia). Dept. of Chemistry; Grishmanov, V; Tanaka, S

    1998-03-01

    The radiolysis of Li{sub 2}O ceramics exposed to accelerated electrons (5 MeV) at 380 K was studied in the range of high absorbed doses up to 250 MGy. The formation of radiation defects (RD) and radiolysis products (RP) was demonstrated to occur simultaneously in the regions of (1) the regular crystalline lattice and (2) an enhanced content of the intrinsic defects and impurities. The production of the electronic RD and RP is more efficient in the region of the defected lattice than that at the site of the regular crystalline lattice. However, the stability of RD and RP formed in the region of the intrinsic defects is far less than those produced at the crystalline lattice, since most of the first mentioned RD and RP disappears with irradiation dose due to the radiation stimulated recombination. By this means the enhanced quantity of RD and RP is localized in the Li{sub 2}O ceramics irradiated to absorbed dose of 40-50 MGy, and hence this can influence the tritium release parameters. As soon as the intrinsic defects have been consumed in the production of RD and RP and the recombination of unstable electronic RD and RP takes place (at dose of {approx}100 MGy), the radiolysis of Li{sub 2}O ceramics occurs only at the crystalline lattice. Furthermore, the concentration of RD and RP increases monotonically and tends to the steady-state level. (author)

  16. Oxidation behaviour of the near α-titanium alloy IMI 834

    Indian Academy of Sciences (India)

    Unknown

    Oxidation behaviour of the near α-titanium alloy IMI 834 was investigated over a range of tem- peratures, from ... perties and adequate resistance against environmental degradation. ... the change of weight of the specimen. The oxidation data.

  17. Evaluation of interface characterization and adhesion of glass ceramics to commercially pure titanium and gold alloy after thermal- and mechanical-loading

    NARCIS (Netherlands)

    Ccahuana Vasqueza, Vanessa Zulema; Ozcan, Mutlu; Kimpara, Estevao Tomomitsu

    Objectives. This study evaluated the effect of thermal- and mechanical-cycling on the shear bond strength of three low-fusing glassy matrix dental ceramics to commercial pure titanium (cpTi) when compared to conventional feldspathic ceramic fused to gold alloy. Methods. Metallic frameworks

  18. Low-temperature atmospheric oxidation of mixtures of titanium and carbon black or brown

    International Nuclear Information System (INIS)

    Elizarova, V.A.; Babaitsev, I.V.; Barzykin, V.V.; Gerusova, V.P.; Rozenband, V.I.

    1984-01-01

    This article reports on the thermogravimetric investigation of mixtures of titanium no. 2 and carbon black with various mass carbon contents. Adding carbon black (as opposed to boron) to titanium leads to an increase in the rate of heat release of the oxidation reaction. An attempt is made to clarify the low-temperature oxidation mechanism of titanium mixtures in air. An x-ray phase and chemical (for bound carbon) analysis of specimens of a stoichiometric Ti + C mixture after heating in air to a temperature of 650 0 C at the rate of 10 0 /min was conducted. The results indicate that the oxidation of the titanium-carbon mixture probably proceeds according to a more complex mechanism associated with the transport of the gaseous carbon oxidation products and their participation in the titanium oxidation

  19. High temperature synthesis of ceramic composition by directed reaction of molten titanium or zirconium with boron carbide

    International Nuclear Information System (INIS)

    Johnson, W.B.

    1990-01-01

    Alternative methods of producing ceramics and ceramic composites include sintering, hot pressing and more recently hot isostatic pressing (HIP) and self-propagating high temperature synthesis (SHS). Though each of these techniques has its advantages, each suffers from several restrictions as well. Sintering may require long times at high temperatures and for most materials requires sintering aids to get full density. These additives can, and generally do, change (often degrade) the properties of the ceramic. Hot pressing and hot isostatic pressing are convenient methods to quickly prepare samples of some materials to full density, but generally are expensive and may damage some types of reinforcements during densification. This paper focuses on the preparation and processing of composites prepared by the directed reaction of molten titanium or zirconium with boron carbide. Advantages and disadvantages of this approach when compared to traditional methods are discussed, with reference to specific examples. Examples of microstructure are properties of these materials are reported

  20. Effects of titanium on a ferritic steel oxidation at 950 C

    Energy Technology Data Exchange (ETDEWEB)

    Issartel, C.; Buscail, H.; Caudron, E.; Cueff, R.; Riffard, F.; El Messki, S.; Karimi, N. [Lab. Vellave sur l' Elaboration et l' Etude des Materiaux (LVEEM), IUT de Clermont-Fd1 - Dept. de Chimie - Science des materiaux, Le Puy en Velay (France); Antoni, L. [CEA Grenoble, DTEN/SCSE/LHPAC (France)

    2004-07-01

    This work presents the titanium effect on the oxidation behaviour of chromia-forming alloys at 950 C. When the amount of titanium is high enough in the substrate, in situ XRD permit to show that this element reacts with oxygen to form Cr{sub 2}TiO{sub 5}. This oxide is quickly transformed into TiO{sub 2} during the first hours of oxidation. These oxides contribute to an increase of the mass gain registered. Titanium leads to a doping effect of the chromia layer inducing an increase of the cationic vacancies concentration and chromium diffusion. (orig.)

  1. Determination of copper oxidizing power in superconducting yttrium ceramics

    International Nuclear Information System (INIS)

    Pontaler, R.P.; Lebed', N.B.

    1989-01-01

    A new photometric method for determining the formal copper degree of oxidation and oxygen deficiency in superconducting high-temperature oxides containing yttrium, barium and copper is developed. The method is based on oxidation of Co(2) complex with EDTA by Cu(3) ions in acetrate buffer solution with pH 4.2-4.7 and allows one to determine 1-10% of Cu(3). Relative standard deviation when determining Cu(3) makes up 0.03-0.05. Using a qualitative reaction with the application of sodium vanadate hydrochloride solution the absence of peroxide compound in superconducting yttrium ceramics is ascertained

  2. Characterization of Titanium Oxide Nanoparticles Obtained by Hydrolysis Reaction of Ethylene Glycol Solution of Alkoxide

    International Nuclear Information System (INIS)

    Uekawa, N.; Endo, N.; Ishii, K.; Kojima, T.; Kakegawa, K.

    2012-01-01

    Transparent and stable sols of titanium oxide nanoparticles were obtained by heating a mixture of ethylene glycol solution of titanium tetraisopropoxide (TIP) and a NH 3 aqueous solution at 368 K for 24 h. The concentration of NH 3 aqueous solution affected the structure of the obtained titanium oxide nanoparticles. For NH 3 aqueous solution concentrations higher than 0.2 mol/L, a mixture of anatase TiO 2 nanoparticles and layered titanic acid nanoparticles was obtained. The obtained sol was very stable without formation of aggregated precipitates and gels. Coordination of ethylene glycol to Ti4+ ions inhibited the rapid hydrolysis reaction and aggregation of the obtained nanoparticles. The obtained titanium oxide nanoparticles had a large specific surface area: larger than 350 m2/g. The obtained titanium oxide nanoparticles showed an enhanced adsorption towards the cationic dye molecules. The selective adsorption corresponded to presence of layered titanic acid on the obtained anatase TiO 2 nanoparticles.

  3. Glass/Ceramic Composites for Sealing Solid Oxide Fuel Cells

    Science.gov (United States)

    Bansal, Narottam P.; Choi, Sung R.

    2007-01-01

    A family of glass/ceramic composite materials has been investigated for use as sealants in planar solid oxide fuel cells. These materials are modified versions of a barium calcium aluminosilicate glass developed previously for the same purpose. The composition of the glass in mole percentages is 35BaO + 15CaO + 5Al2O3 + 10B2O3 + 35SiO2. The glass seal was found to be susceptible to cracking during thermal cycling of the fuel cells. The goal in formulating the glass/ ceramic composite materials was to (1) retain the physical and chemical advantages that led to the prior selection of the barium calcium aluminosilicate glass as the sealant while (2) increasing strength and fracture toughness so as to reduce the tendency toward cracking. Each of the composite formulations consists of the glass plus either of two ceramic reinforcements in a proportion between 0 and 30 mole percent. One of the ceramic reinforcements consists of alumina platelets; the other one consists of particles of yttria-stabilized zirconia wherein the yttria content is 3 mole percent (3YSZ). In preparation for experiments, panels of the glass/ceramic composites were hot-pressed and machined into test bars.

  4. Manufacturing of porous oxide ceramics by replication of plant morphologies

    Energy Technology Data Exchange (ETDEWEB)

    Sieber, H.; Rambo, C.; Cao, J.; Vogli, E.; Greil, P. [Erlangen-Nuernberg Univ., Erlangen (DE). Dept. of Materials Science (III) Glass and Ceramics

    2002-07-01

    Biomorphic oxide ceramics of alumina, mullite and zirconia with a directed pore morphology on the micrometer level were manufactured from bioorganic plant structures by sol-gel processing as well as sol-assisted nano-powder infiltrations. The inherent open porous morphology of natural grown rattan palms was used for vacuum-infiltration with aluminum isopropoxide (Al(OC{sub 3}H{sub 7}){sub 3}), zirconium oxichloride (ZrOCl{sub 2}.8H{sub 2}O) and SiO{sub 2} nano powder. Hydrolysis of the sols by adding HNO{sub 3} and pyrolysis in inert atmosphere at 800 C resulted in the formation of biocarbon/ceramic replica of the original wood morphology. The specimens were sintered in air at temperatures up to 1600 C to yield porous oxide ceramics with an unidirected pore structure similar to the original plant material. Repeated infiltration, hydrolysis and annealing steps were applied to increase the density of the ceramic materials. (orig.)

  5. Ceramic material suitable for repair of a space vehicle component in a microgravity and vacuum environment, method of making same, and method of repairing a space vehicle component

    Science.gov (United States)

    Riedell, James A. (Inventor); Easler, Timothy E. (Inventor)

    2009-01-01

    A precursor of a ceramic adhesive suitable for use in a vacuum, thermal, and microgravity environment. The precursor of the ceramic adhesive includes a silicon-based, preceramic polymer and at least one ceramic powder selected from the group consisting of aluminum oxide, aluminum nitride, boron carbide, boron oxide, boron nitride, hafnium boride, hafnium carbide, hafnium oxide, lithium aluminate, molybdenum silicide, niobium carbide, niobium nitride, silicon boride, silicon carbide, silicon oxide, silicon nitride, tin oxide, tantalum boride, tantalum carbide, tantalum oxide, tantalum nitride, titanium boride, titanium carbide, titanium oxide, titanium nitride, yttrium oxide, zirconium diboride, zirconium carbide, zirconium oxide, and zirconium silicate. Methods of forming the ceramic adhesive and of repairing a substrate in a vacuum and microgravity environment are also disclosed, as is a substrate repaired with the ceramic adhesive.

  6. Additive manufacturing of Ti-Si-N ceramic coatings on titanium

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yanning; Sahasrabudhe, Himanshu; Bandyopadhyay, Amit, E-mail: amitband@wsu.edu

    2015-08-15

    Highlights: • 3D Printing or additive manufacturing of hard Ti-Si-N based ceramics coating on Ti metal substrate. • Understanding of phase transformation as a function of compositional variation. • Evaluation of influence of processing parameters and composition on wear resistance. - Abstract: In this study, Laser Engineered Net Shaping (LENS{sup TM}) was employed towards Additive Manufacturing/3D Printing of Ti-Si-N coatings with three different Ti-Si ratios on commercially pure titanium (cp-Ti) substrate. Microstructural analysis, phase analysis using X-ray diffraction, wear resistance and hardness measurements were done on LENS™ processed 3D printed coatings. Coatings showed graded microstructures and in situ formed phases. Results showed that microstructural variations and phase changes influence coating's hardness and wear resistance directly. High hardness values were obtained from all samples’ top surface where the hardness of coatings can be ranked as 90% Ti-10% Si-N coating (2093.67 ± 144 HV{sub 0.2}) > 100% Ti-N coating (1846 ± 68.5 HV{sub 0.2}) > 75% Ti-25% Si-N coating (1375.3 ± 61.4 HV{sub 0.2}). However, wear resistance was more dependent on inherent Si content, and samples with higher Si content showed better wear resistance.

  7. Additive manufacturing of Ti-Si-N ceramic coatings on titanium

    International Nuclear Information System (INIS)

    Zhang, Yanning; Sahasrabudhe, Himanshu; Bandyopadhyay, Amit

    2015-01-01

    Highlights: • 3D Printing or additive manufacturing of hard Ti-Si-N based ceramics coating on Ti metal substrate. • Understanding of phase transformation as a function of compositional variation. • Evaluation of influence of processing parameters and composition on wear resistance. - Abstract: In this study, Laser Engineered Net Shaping (LENS TM ) was employed towards Additive Manufacturing/3D Printing of Ti-Si-N coatings with three different Ti-Si ratios on commercially pure titanium (cp-Ti) substrate. Microstructural analysis, phase analysis using X-ray diffraction, wear resistance and hardness measurements were done on LENS™ processed 3D printed coatings. Coatings showed graded microstructures and in situ formed phases. Results showed that microstructural variations and phase changes influence coating's hardness and wear resistance directly. High hardness values were obtained from all samples’ top surface where the hardness of coatings can be ranked as 90% Ti-10% Si-N coating (2093.67 ± 144 HV 0.2 ) > 100% Ti-N coating (1846 ± 68.5 HV 0.2 ) > 75% Ti-25% Si-N coating (1375.3 ± 61.4 HV 0.2 ). However, wear resistance was more dependent on inherent Si content, and samples with higher Si content showed better wear resistance

  8. Polymer derived non-oxide ceramics modified with late transition metals.

    Science.gov (United States)

    Zaheer, Muhammad; Schmalz, Thomas; Motz, Günter; Kempe, Rhett

    2012-08-07

    This tutorial review highlights the methods for the preparation of metal modified precursor derived ceramics (PDCs) and concentrates on the rare non-oxide systems enhanced with late transition metals. In addition to the main synthetic strategies for modified SiC and SiCN ceramics, an overview of the morphologies, structures and compositions of both, ceramic materials and metal (nano) particles, is presented. Potential magnetic and catalytic applications have been discussed for the so manufactured metal containing non-oxide ceramics.

  9. Doped titanium oxide photcatalysts: Preparation, structure and interaction with viruses

    Science.gov (United States)

    Li, Qi

    Since the discovery of photoelectrochemical splitting of water on n-titanium oxide (n-TiO2) electrodes by Fujishima and Honda in 1972, there has been much interest in semiconductor-based materials as photocatalysts for both solar energy conversion and environmental applications in the past several decades. Among various semiconductor-based photocatalysts, TiO2 is the only candidate suitable for industrial use because of its high chemical stability, good photoactivity, relatively low cost, and nontoxicity. However, the photocatalytic capability of TiO 2 is limited to only ultraviolet (UV) light (wavelength, lambda, strategy to use atomic force microscope (AFM) to conduct in-situ observation of viruses on semiconductor surfaces in aqueous environment was developed, which combines information from both height profile and phase profile and solves the difficulty of observing small nanosized biomolecules on substrates with similar feature sizes.

  10. [A new port catheter system of aluminum oxide ceramics].

    Science.gov (United States)

    Haindl, H; Schmoll, E; Willmann, G

    1995-03-01

    Implantable port catheter systems are becoming increasingly important, as they often permit out-patient treatment for many indications that would otherwise require hospitalization. Moreover, they also increase the safety/reliability of infusion therapy in critical inpatients. For a variety of reasons, the materials used so far, i.e. steel, titanium and various plastics have not been completely satisfactory. The main disadvantage of metallic systems is the formation of artefacts in tomographic images, while the shortcomings of plastics are mechanical, e.g. chip formation and early membrane failure. Against this background, a port catheter system made of alumina ceramic, which is largely free of the disadvantages of the other materials, was developed. The expected advantages in terms of complication rate and radiological artefacts, were fully confirmed by the evaluation of 160 monitored patients.

  11. Nanosystems in Ceramic Oxides Created by Means of Ion Implantation

    OpenAIRE

    Van Huis, M.A.

    2003-01-01

    The material properties of nanometer-sized clusters are dependent on the cluster size. Changing the cluster dimensions induces structural phase transformations, metal-insulator transitions, non-linear optical properties and widening of the band gap of semiconductors. In this work, nanoclusters are created by ion implantation followed by thermal annealing. The ceramic oxides MgO and Al2O3 are used as embedding materials because of their stability and optical transparency. All clusters were cre...

  12. Dispersion toughened silicon carbon ceramics

    Science.gov (United States)

    Wei, G.C.

    1984-01-01

    Fracture resistant silicon carbide ceramics are provided by incorporating therein a particulate dispersoid selected from the group consisting of (a) a mixture of boron, carbon and tungsten, (b) a mixture of boron, carbon and molybdenum, (c) a mixture of boron, carbon and titanium carbide, (d) a mixture of aluminum oxide and zirconium oxide, and (e) boron nitride. 4 figures.

  13. Facile hydrothermal preparation of titanium dioxide decorated reduced graphene oxide nanocomposite

    Science.gov (United States)

    Chang, Betty Yea Sze; Huang, Nay Ming; An’amt, Mohd Nor; Marlinda, Abdul Rahman; Norazriena, Yusoff; Muhamad, Muhamad Rasat; Harrison, Ian; Lim, Hong Ngee; Chia, Chin Hua

    2012-01-01

    A simple single-stage approach, based on the hydrothermal technique, has been introduced to synthesize reduced graphene oxide/titanium dioxide nanocomposites. The titanium dioxide nanoparticles are formed at the same time as the graphene oxide is reduced to graphene. The triethanolamine used in the process has two roles. It acts as a reducing agent for the graphene oxide as well as a capping agent, allowing the formation of titanium dioxide nanoparticles with a narrow size distribution (~20 nm). Transmission electron micrographs show that the nanoparticles are uniformly distributed on the reduced graphene oxide nanosheet. Thermogravimetric analysis shows the nanocomposites have an enhanced thermal stability over the original components. The potential applications for this technology were demonstrated by the use of a reduced graphene oxide/titanium dioxide nanocomposite-modified glassy carbon electrode, which enhanced the electrochemical performance compared to a conventional glassy carbon electrode when interacting with mercury(II) ions in potassium chloride electrolyte. PMID:22848166

  14. Osseointegration is improved by coating titanium implants with a nanostructured thin film with titanium carbide and titanium oxides clustered around graphitic carbon

    Energy Technology Data Exchange (ETDEWEB)

    Veronesi, Francesca [Laboratory of Preclinical and Surgical Studies, Rizzoli Orthopedic Institute, Via Di Barbiano 1/10, Bologna 40136 (Italy); Giavaresi, Gianluca; Fini, Milena [Laboratory of Preclinical and Surgical Studies, Rizzoli Orthopedic Institute, Via Di Barbiano 1/10, Bologna 40136 (Italy); Laboratory of Biocompatibility, Innovative Technologies and Advanced Therapies, Department Rizzoli RIT, Via Di Barbiano 1/10, Bologna 40136 (Italy); Longo, Giovanni [CNR Istituto di Struttura della Materia, CNR, Via del Fosso del Cavaliere 100, 00133 Roma (Italy); Ioannidu, Caterina Alexandra; Scotto d' Abusco, Anna [Dept. of Biochemical Sciences, Sapienza University of Roma, Ple A. Moro 5, 00185 Roma (Italy); Superti, Fabiana; Panzini, Gianluca [Dept. of Technologies and Health, Istituto Superiore di Sanità, Viale Regina Elena, 299 Roma (Italy); Misiano, Carlo [Romana Film Sottili, Anzio, Roma (Italy); Palattella, Alberto [Dept. of Clinical Sciences and Translational Medicine, Tor Vergata University, Via Montpellier 1, 00133 Roma (Italy); Selleri, Paolo; Di Girolamo, Nicola [Exotic Animals Clinic, Via S. Giovannini 53, 00137 Roma (Italy); Garbarino, Viola [Dept. of Radiology, S.M. Goretti Hospital, Via G. Reni 2, 04100 Latina (Italy); Politi, Laura [Dept. of Biochemical Sciences, Sapienza University of Roma, Ple A. Moro 5, 00185 Roma (Italy); Scandurra, Roberto, E-mail: roberto.scandurra@uniroma1.it [Dept. of Biochemical Sciences, Sapienza University of Roma, Ple A. Moro 5, 00185 Roma (Italy)

    2017-01-01

    Titanium implants coated with a 500 nm nanostructured layer, deposited by the Ion Plating Plasma Assisted (IPPA) technology, composed of 60% graphitic carbon, 25% titanium oxides and 15% titanium carbide were implanted into rabbit femurs whilst into the controlateral femurs uncoated titanium implants were inserted as control. At four time points the animals were injected with calcein green, xylenol orange, oxytetracycline and alizarin. After 2, 4 and 8 weeks femurs were removed and processed for histology and static and dynamic histomorphometry for undecalcified bone processing into methylmethacrylate, sectioned, thinned, polished and stained with Toluidine blue and Fast green. The overall bone-implant contacts rate (percentage of bone-implant contacts/weeks) of the TiC coated implant was 1.6 fold than that of the uncoated titanium implant. The histomorphometric analyses confirmed the histological evaluations. More precisely, higher Mineral Apposition Rate (MAR, μm/day) (p < 0.005) and Bone Formation Rate (BFR, μm{sup 2}/μm/day) (p < 0.0005) as well as Bone Implant Contact (Bic) and Bone Ingrowth values (p < 0.0005) were observed for the TiC coated implants compared to uncoated implants. In conclusion the hard nanostructured TiC layer protects the bulk titanium implant against the harsh conditions of biological tissues and in the same time, stimulating adhesion, proliferation and activity of osteoblasts, induces a better bone-implant contacts of the implant compared to the uncoated titanium implant. - Highlights: • Ti implants were coated with a nanostructured film composed of C{sub gr}, TiC and TiO{sub x}. • The TiC layer stimulates adhesion, proliferation and activity of osteoblasts. • Uncoated and TiC coated titanium implants were implanted in rabbit femurs. • Bone-implant contacts of TiC coated implants were higher than that of uncoated. • Mineral Apposition Rate of TiC coated implants were higher than that of uncoated.

  15. Osseointegration is improved by coating titanium implants with a nanostructured thin film with titanium carbide and titanium oxides clustered around graphitic carbon

    International Nuclear Information System (INIS)

    Veronesi, Francesca; Giavaresi, Gianluca; Fini, Milena; Longo, Giovanni; Ioannidu, Caterina Alexandra; Scotto d'Abusco, Anna; Superti, Fabiana; Panzini, Gianluca; Misiano, Carlo; Palattella, Alberto; Selleri, Paolo; Di Girolamo, Nicola; Garbarino, Viola; Politi, Laura; Scandurra, Roberto

    2017-01-01

    Titanium implants coated with a 500 nm nanostructured layer, deposited by the Ion Plating Plasma Assisted (IPPA) technology, composed of 60% graphitic carbon, 25% titanium oxides and 15% titanium carbide were implanted into rabbit femurs whilst into the controlateral femurs uncoated titanium implants were inserted as control. At four time points the animals were injected with calcein green, xylenol orange, oxytetracycline and alizarin. After 2, 4 and 8 weeks femurs were removed and processed for histology and static and dynamic histomorphometry for undecalcified bone processing into methylmethacrylate, sectioned, thinned, polished and stained with Toluidine blue and Fast green. The overall bone-implant contacts rate (percentage of bone-implant contacts/weeks) of the TiC coated implant was 1.6 fold than that of the uncoated titanium implant. The histomorphometric analyses confirmed the histological evaluations. More precisely, higher Mineral Apposition Rate (MAR, μm/day) (p < 0.005) and Bone Formation Rate (BFR, μm 2 /μm/day) (p < 0.0005) as well as Bone Implant Contact (Bic) and Bone Ingrowth values (p < 0.0005) were observed for the TiC coated implants compared to uncoated implants. In conclusion the hard nanostructured TiC layer protects the bulk titanium implant against the harsh conditions of biological tissues and in the same time, stimulating adhesion, proliferation and activity of osteoblasts, induces a better bone-implant contacts of the implant compared to the uncoated titanium implant. - Highlights: • Ti implants were coated with a nanostructured film composed of C gr , TiC and TiO x . • The TiC layer stimulates adhesion, proliferation and activity of osteoblasts. • Uncoated and TiC coated titanium implants were implanted in rabbit femurs. • Bone-implant contacts of TiC coated implants were higher than that of uncoated. • Mineral Apposition Rate of TiC coated implants were higher than that of uncoated.

  16. Sol-gel/hydrothermal synthesis of mixed metal oxide of Titanium and ...

    African Journals Online (AJOL)

    Mixed metal oxides of titanium and zinc nanocomposites were prepared through sol-gel method under hydrothermal condition using titanium oxy-(1, 2 - pentadione) and zinc acetate without hazardous additives. The resulting composites were characterized by X-Ray Diffractometer (XRD), Scanning Electron Microscope ...

  17. Multi-metal oxide ceramic nanomaterial

    Science.gov (United States)

    O'Brien, Stephen; Liu, Shuangyi; Huang, Limin

    2016-06-07

    A convenient and versatile method for preparing complex metal oxides is disclosed. The method uses a low temperature, environmentally friendly gel-collection method to form a single phase nanomaterial. In one embodiment, the nanomaterial consists of Ba.sub.AMn.sub.BTi.sub.CO.sub.D in a controlled stoichiometry.

  18. Zirconium oxide based ceramic solid electrolytes for oxygen detection

    International Nuclear Information System (INIS)

    Caproni, Erica

    2007-01-01

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

  19. Nanoporous titanium niobium oxide and titanium tantalum oxide compositions and their use in anodes of lithium ion batteries

    Science.gov (United States)

    Dai, Sheng; Guo, Bingkun; Sun, Xiao-Guang; Qiao, Zhenan

    2017-10-31

    Nanoporous metal oxide framework compositions useful as anodic materials in a lithium ion battery, the composition comprising metal oxide nanocrystals interconnected in a nanoporous framework and having interconnected channels, wherein the metal in said metal oxide comprises titanium and at least one metal selected from niobium and tantalum, e.g., TiNb.sub.2-x Ta.sub.xO.sub.y (wherein x is a value from 0 to 2, and y is a value from 7 to 10) and Ti.sub.2Nb.sub.10-vTa.sub.vO.sub.w (wherein v is a value from 0 to 2, and w is a value from 27 to 29). A novel sol gel method is also described in which sol gel reactive precursors are combined with a templating agent under sol gel reaction conditions to produce a hybrid precursor, and the precursor calcined to form the anodic composition. The invention is also directed to lithium ion batteries in which the nanoporous framework material is incorporated in an anode of the battery.

  20. Formation of titanium diboride coatings during the anodic polarization of titanium in a chloride melt with a low boron oxide content

    Science.gov (United States)

    Elshina, L. A.; Malkov, V. B.; Molchanova, N. G.

    2015-02-01

    The corrosion-electrochemical behavior of titanium in a molten eutectic mixture of cesium and sodium chlorides containing up to 1 wt % boron oxide is studied in the temperature range 810-870 K in an argon atmosphere. The potential, the current, and the rate of titanium corrosion are determined. The optimum conditions of forming a dense continuous titanium diboride coating on titanium with high adhesion to the metallic base are found for the anodic activation of titanium in the molten electrolyte under study.

  1. Corrosion behaviour of nanometre sized cerium oxide and titanium oxide incorporated aluminium in NaCl solution

    International Nuclear Information System (INIS)

    Ashraf, P. Muhamed; Edwin, Leela

    2013-01-01

    Highlights: ► Corrosion resistant aluminium incorporated with nano oxides of cerium and titanium. ► 0.2% nano CeO 2 and 0.05% nano TiO 2 showed increased corrosion resistance. ► Nano TiO 2 concentration influenced the optimum performance of the material. ► Comparison of Micro and nano CeO 2 and TiO 2 aluminium showed the latter is best. - Abstract: The study highlights the development of an aluminium matrix composite by incorporating mixture of nanometre sized cerium oxide and titanium oxide in pure aluminium and its corrosion resistance in marine environment. The mixed nanometre sized oxides incorporated aluminium exhibited improved microstructure and excellent corrosion resistance. Corrosion resistance depends on the concentration of nanometre sized titanium oxide. Electrochemical characteristics improved several folds in nanometre sized mixed oxides incorporated aluminium than micrometre sized oxides incorporated aluminium.

  2. Influence of titanium oxide films on copper nucleation during electrodeposition

    International Nuclear Information System (INIS)

    Chang, Hyun K.; Choe, Byung-Hak; Lee, Jong K.

    2005-01-01

    Copper electrodeposition has an important industrial role because of various interconnects used in electronic devices such as printed wire boards. With an increasing trend in device miniaturization, in demand are void-free, thin copper foils of 10 μm thick or less with a very low surface profile. In accordance, nucleation kinetics of copper was studied with titanium cathodes that were covered with thin, passive oxide films of 2-3 nm. Such an insulating oxide layer with a band gap of 3 eV is supposed to nearly block charge transfer from the cathode to the electrolyte. However, significant nucleation rates of copper were observed. Pipe tunneling mechanism along a dislocation core is reasoned to account for the high nucleation kinetics. A dislocation core is proposed to be a high electron tunneling path with a reduced energy barrier and a reduced barrier thickness. In supporting the pipe tunneling mechanism, both 'in situ' and 'ex situ' scratch tests were performed to introduce extra dislocations into the cathode surface, that is, more high charge paths via tunneling, before electrodeposition

  3. Bloodcompatibility improvement of titanium oxide film modified by phosphorus ion implantation

    International Nuclear Information System (INIS)

    Yang, P.; Leng, Y.X.; Zhao, A.S.; Zhou, H.F.; Xu, L.X.; Hong, S.; Huang, N.

    2006-01-01

    Our recent investigation suggested that Ti-O thin film could be a newly developed antithrombotic material and its thromboresistance could be related to its physical properties of wide gap semiconductor. In this work, titanium oxide film was modified by phosphorus ion implantation and succeeding vacuum annealing. RBS were used to investigate phosphorus distribution profile. Contact angle test results show that phosphorus-doped titanium oxide film becomes more hydrophilic after higher temperature annealing, while its electric conductivity increases. Antithrombotic property of phosphorus-doped titanium oxide thin films was examined by clotting time and platelet adhesion tests. The results suggest that phosphorus doping is an effective way to improve the bloodcompatibility of titanium oxide film, and it is related to the changes of electron structure and surface properties caused by phosphorus doping

  4. Characterization polyethylene terephthalate nanocomposites mixing with nano-silica and titanium oxide

    Directory of Open Access Journals (Sweden)

    Rusu Mircea A.

    2017-01-01

    Full Text Available Polyethylene terephthalate (PET based nanocomposites containing nano-silica (Aerosil (Degusa and titanium oxide (TiO2 (Merk were prepared by melt compounding. Influence of nano-silica and titanium oxide on properties of the resulting nanocomposites was investigated by scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FTIR and atomic force microscopy (AFM. The possible interaction between nano-silica and titanium oxide particles with PET functional groups at bulk and surface was elucidated by transmission of FTIR-ATR spectroscopy. AFM studies of the resulting nanocomposites showed an increased surface roughness compared to pure PET. SEM images illustrated that nano-silica particles have tendency to migrate to the surface of the PET matrix much more than titanium oxide powder.

  5. Surface electronic and structural properties of nanostructured titanium oxide grown by pulsed laser deposition

    NARCIS (Netherlands)

    Fusi, M.; Maccallini, E.; Caruso, T.; Casari, C. S.; Bassi, A. Li; Bottani, C. E.; Rudolf, P.; Prince, K. C.; Agostino, R. G.

    Titanium oxide nanostructured thin films synthesized by pulsed laser deposition (PLD) were here characterized with a multi-technique approach to investigate the relation between surface electronic, structural and morphological properties. Depending on the growth parameters, these films present

  6. Deposition of thin film of titanium on ceramic substrate using the discharge for hollow cathode for Al2O3/Al2O3 indirect brazing

    Directory of Open Access Journals (Sweden)

    Mary Roberta Meira Marinho

    2009-01-01

    Full Text Available Thin films of titanium were deposited onto Al2O3 substrate by hollow cathode discharge method for the formation of a ceramic-ceramic joint using indirect brazing method. An advantage of using this technique is that a relatively small amount of titanium is required for the metallization of the ceramic surface when compared with other conventional methods. Rapidly solidified brazing filler of Cu49Ag45Ce6 in the form of ribbons was used. The thickness of deposited titanium layer and the brazing temperature/time were varied. The quality of the brazed joint was evaluated through the three point bending flexural tests. The brazed joints presented high flexural resistance values up to 176 MPa showing the efficiency of the technique.

  7. Passivation of Titanium Oxide in Polyethylene Matrices using Polyelectrolytes as Titanium Dioxide Surface Coating

    Directory of Open Access Journals (Sweden)

    Javier Vallejo-Montesinos

    2017-05-01

    Full Text Available One of the major challenges of the polyolefins nowadays is the ability of those to resist weathering conditions, specially the photodegradation process that suffer any polyolefin. A common way to prevent this, is the use of hindered amine light stabilizers (HALS are employed. An alternative route to avoid photodegradation is using polyelectrolites as coating of fillers such as metal oxides. Composites of polyethylene were made using titanium dioxide (TiO2 as a filler with polyelectrolytes (polyethylenimine and sodium polystyrene sulfonate attached to its surface, to passivate its photocatalytic activity. We exposed the samples to ultraviolet-visible (UV-Vis light to observe the effect of radiation on the degradation of coated samples, compared to those without the polyelectrolyte coating. From the experimental results, we found that polyethylenimine has a similar carbonyl signal area to the sample coated with hindered amine light stabilizers (HALS while sodium polystyrene sulfonate exhibit more degradation than the HALS coated samples, but it passivates the photocatalytic effect when compared with the non-coated TiO2 samples. Also, using AFM measurements, we confirmed that the chemical nature of polyethylenimine causes the TiO2 avoid the migration to the surface during the extrusion process, inhibiting the photodegradation process and softening the sample. On this basis, we found that polyethylenimine is a good choice for reducing the degradation caused by TiO2 when it is exposed to UV-Vis light.

  8. Microstructure evolution during pressureless sintering of bulk oxide ceramics

    Directory of Open Access Journals (Sweden)

    Karel Maca

    2009-06-01

    Full Text Available The author’s experience concerning the infl uence of the choice of different pressureless heating schedules on the fi nal microstructure of oxide ceramic materials is summarized in the paper. Alumina, ceria, strontium titanate, as well as tetragonal (3 mol% Y2O3 and cubic (8 mol% Y2O3 zirconia were cold isostatically pressed or injection moulded and pressureless sintered with different heating schedules – namely with Constant-Rate of Heating with different dwell temperatures (CRH, with Rate-Controlled Sintering (RCS and with Two-Step Sintering (TSS. It was examined whether some of these three sintering schedules, with the same fi nal density achieved, can lead to a decrease of the grain size of sintered ceramics. The results showed that only TSS (and only for selected materials brought significant decrease of the grain size.

  9. Core–Shell Electrospun Hollow Aluminum Oxide Ceramic Fibers

    Directory of Open Access Journals (Sweden)

    Jonathan W. Rajala

    2015-10-01

    Full Text Available In this work, core–shell electrospinning was employed as a simple method for the fabrication of composite coaxial polymer fibers that became hollow ceramic tubes when calcined at high temperature. The shell polymer solution consisted of polyvinyl pyrollidone (PVP in ethanol mixed with an aluminum acetate solution to act as a ceramic precursor. The core polymer was recycled polystyrene to act as a sacrificial polymer that burned off during calcination. The resulting fibers were analyzed with X-ray diffraction (XRD and energy dispersive spectroscopy (EDS to confirm the presence of gamma-phase aluminum oxide when heated at temperatures above 700 °C. The fiber diameter decreased from 987 ± 19 nm to 382 ± 152 nm after the calcination process due to the polymer material being burned off. The wall thickness of these fibers is estimated to be 100 nm.

  10. Titanium oxidation-reduction at low oxygen pressure under electron bombardment

    International Nuclear Information System (INIS)

    Brasca, R.; Passeggi, M.C.G.; Ferron, J.

    2006-01-01

    The effect of the electron bombardment on the first stages of the titanium oxidation process has been studied by means of Auger Electron Spectroscopy. Using Factor Analysis and the valence electron dependence behaviour of the titanium LMV Auger transition, we found that the process is strongly dependent on the oxygen pressure and electron current density. Depending on the irradiation conditions, films of different thickness and Ti oxidized states are obtained

  11. Microstructural variation in titanium oxide thin films deposited by DC magnetron sputtering

    International Nuclear Information System (INIS)

    Pandian, Ramanathaswamy; Natarajan, Gomathi; Kamruddin, M.; Tyagi, A.K.

    2013-01-01

    We report on the microstructural evolution of titanium oxide thin films deposited by reactive DC magnetron sputtering using titanium metal target. By varying the ratio of sputter-gas mixture containing argon, oxygen and nitrogen various phases of titanium oxide, almost pure rutile, rutile-rich and anatase-rich nano-crystalline, were deposited on Si substrates at room temperature. Using high-resolution scanning electron microscopy, X-ray diffraction and micro-Raman techniques the microstructure of the films were revealed. The relationship between the microstructure of the films and the oxygen partial pressure during sputtering is discussed

  12. Characterization of Titanium Oxide Nanoparticles Obtained by Hydrolysis Reaction of Ethylene Glycol Solution of Alkoxide

    OpenAIRE

    Naofumi Uekawa; Naoya Endo; Keisuke Ishii; Takashi Kojima; Kazuyuki Kakegawa

    2012-01-01

    Transparent and stable sols of titanium oxide nanoparticles were obtained by heating a mixture of ethylene glycol solution of titanium tetraisopropoxide (TIP) and a NH3 aqueous solution at 368 K for 24 h. The concentration of NH3 aqueous solution affected the structure of the obtained titanium oxide nanoparticles. For NH3 aqueous solution concentrations higher than 0.2 mol/L, a mixture of anatase TiO2 nanoparticles and layered titanic acid nanoparticles was obtained. The obtained sol was very...

  13. Interdisciplinary approach to cell–biomaterial interactions: biocompatibility and cell friendly characteristics of RKKP glass–ceramic coatings on titanium

    International Nuclear Information System (INIS)

    Ledda, Mario; Lolli, Maria Grazia; Lisi, Antonella; De Bonis, Angela; Teghil, Roberto; Bertani, Francesca Romana; Cacciotti, Ilaria; Ravaglioli, Antonio; Rau, Julietta V

    2015-01-01

    In this work, titanium (Ti) supports have been coated with glass–ceramic films for possible applications as biomedical implant materials in regenerative medicine. For the film preparation, a pulsed laser deposition (PLD) technique has been applied. The RKKP glass–ceramic material, used for coating deposition, was a sol–gel derived target of the following composition: Ca-19.4, P-4.6, Si-17.2, O-43.5, Na-1.7, Mg-1.3, F-7.2, K-0.2, La-0.8, Ta-4.1 (all in wt%). The prepared coatings were compact and uniform, characterised by a nanometric average surface roughness. The biocompatibility and cell-friendly properties of the RKKP glass–ceramic material have been tested. Cell metabolic activity and proliferation of human colon carcinoma CaCo-2 cells seeded on RKKP films showed the same exponential trend found in the control plastic substrates. By the phalloidin fluorescence analysis, no significant modifications in the actin distribution were revealed in cells grown on RKKP films. Moreover, in these cells a high mRNA expression of markers involved in protein synthesis, proliferation and differentiation, such as villin (VIL1), alkaline phosphatase (ALP1), β-actin (β-ACT), Ki67 and RPL34, was recorded. In conclusion, the findings, for the first time, demonstrated that the RKKP glass–ceramic material allows the adhesion, growth and differentiation of the CaCo-2 cell line. (paper)

  14. Self-assembled nanostructures in oxide ceramics

    Science.gov (United States)

    Ansari, Haris Masood

    Self-assembled nanoislands in the gadolinia-doped ceria (GDC)/ yttria-stabilized zirconia (YSZ) system have recently been discovered. This dissertation is an attempt to study the mechanism by which these nanoislands form. Nanoislands in the GDC/YSZ system form via a strain based mechanism whereby the stress accumulated in the GDC-doped surface layer on the YSZ substrate is relieved by creation of self-assembled nanoislands by a mechanism similar to the ATG instability. Unlike what was previously believed, a modified surface layer is not required prior to annealing, that is, this modification can occur during annealing by surface diffusion of dopants from the GDC sources (distributed on the YSZ surface in either lithographically defined patch or powder form) with simultaneous breakup, which occurs at the hold temperature independent of the subsequent cooling. Additionally, we have developed a simple powder based process of producing nanoislands which bypasses lithography and thin film deposition setups. The versatility of the process is apparent in the fact that it allows us to study the effect of experimental parameters such as soak time, temperature, cooling rate and the effect of powder composition on nanoisland properties in a facile way. With the help of this process, we have shown that nanoislands are not peculiar to Gd containing oxide source materials on YSZ substrates and can also be produced with other source materials such as La2O3, Nd2O3, Sm 2O3, Eu2O3, Tb2O3 and even Y2O3, which is already present in the substrate and hence simplifies the system further. We have extended our work to include YSZ substrates of the (110) surface orientation and have found that instead of nanoisland arrays, we obtain an array of parallel nanobars which have their long axes oriented along the [1-10] direction on the YSZ-(110) surface. STEM EDS performed on both the bars and the nanoislands has revealed that they are solid YSZ-rich solid solutions with the dopant species and

  15. Optical properties of ytterbium-doped yttrium oxide ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Solomonov, V.I.; Maksimov, R.N. [Institute of Electrophysics UrB RAS, Amundsena 106, 620016 Ekaterinburg (Russian Federation); Ural Federal University Named After the First President of Russia B.N. Yeltsin, Mira 19, 620002 Ekaterinburg (Russian Federation); Osipov, V.V.; Shitov, V.A.; Lipchak, A.I. [Institute of Electrophysics UrB RAS, Amundsena 106, 620016 Ekaterinburg (Russian Federation)

    2017-05-15

    Ytterbium-doped yttrium oxide (Yb:Y{sub 2}O{sub 3}) transparent ceramics with different sintering additives (Lu{sub 2}O{sub 3}, Sc{sub 2}O{sub 3}, CeO{sub 2}, ZrO{sub 2}, or HfO{sub 2}) were fabricated using nanopowders produced by laser ablation. Transmission and photoluminescence spectra of the obtained ceramics were investigated at room temperature. Highest in-line transmittance was over 80% at the wavelength of 1060 nm for 2 mm thick Yb:Y{sub 2}O{sub 3} ceramics with zirconium and hafnium. Divalent Yb ions with the ground state electron configuration 4f{sup 13}6s were revealed. The absorption and emission bands caused by s <-> s transitions of these ions were observed in the IR spectral range of Yb{sup 3+} ions. The superposition of both Yb{sup 3+} and Yb{sup 2+} emission bands leads to an effective broadening of the whole luminescence band. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Oxidative nanopatterning of titanium generates mesoporous surfaces with antimicrobial properties

    Directory of Open Access Journals (Sweden)

    Variola F

    2014-05-01

    Full Text Available Fabio Variola,1,2 Sylvia Francis Zalzal,3 Annie Leduc,3 Jean Barbeau,3 Antonio Nanci31Faculty of Engineering, Department of Mechanical Engineering, 2Faculty of Science, Department of Physics, University of Ottawa, Ottawa, ON, 3Faculty of Dental Medicine, Université de Montréal, Montreal, QC, CanadaAbstract: Mesoporous surfaces generated by oxidative nanopatterning have the capacity to selectively regulate cell behavior, but their impact on microorganisms has not yet been explored. The main objective of this study was to test the effects of such surfaces on the adherence of two common bacteria and one yeast strain that are responsible for nosocomial infections in clinical settings and biomedical applications. In addition, because surface characteristics are known to affect bacterial adhesion, we further characterized the physicochemical properties of the mesoporous surfaces. Focused ion beam (FIB was used to generate ultrathin sections for elemental analysis by energy-dispersive X-ray spectroscopy (EDS, nanobeam electron diffraction (NBED, and high-angle annular dark field (HAADF scanning transmission electron microscopy (STEM imaging. The adherence of Staphylococcus aureus, Escherichia coli and Candida albicans onto titanium disks with mesoporous and polished surfaces was compared. Disks with the two surfaces side-by-side were also used for direct visual comparison. Qualitative and quantitative results from this study indicate that bacterial adhesion is significantly hindered by the mesoporous surface. In addition, we provide evidence that it alters structural parameters of C. albicans that determine its invasiveness potential, suggesting that microorganisms can sense and respond to the mesoporous surface. Our findings demonstrate the efficiency of a simple chemical oxidative treatment in generating nanotextured surfaces with antimicrobial capacity with potential applications in the implant manufacturing industry and hospital setting

  17. Encapsulation of sacrificial silicon containing particles for SH oxide ceramics via a boehmite precursor route

    NARCIS (Netherlands)

    Carabat, A.L.; Van der Zwaag, S.; Sloof, W.G.

    2013-01-01

    Easy crack propagation in oxide ceramic coatings limits their application in high temperature environment (e.g. such as engines and gas turbine components) [1]. In order to overcome this problem, incorporation of sacrificial particles into an oxide ceramic coating may be a viable option. Particles

  18. Ceramic media amended with metal oxide for the capture of viruses in drinking water.

    Science.gov (United States)

    Brown, J; Sobsey, M D

    2009-04-01

    Ceramic materials that can adsorb and/or inactivate viruses in water may find widespread application in low-tech drinking-water treatment technologies in developing countries, where porous ceramic filters and ceramic granular media filters are increasingly promoted for that purpose. We examined the adsorption and subsequent inactivation of bacteriophages MS2 and (phiX-174 on five ceramic media in batch adsorption studies to determine media suitability for use in a ceramic water filter application. The media examined were a kaolinitic ceramic medium and four kaolinitic ceramic media amended with iron or aluminium oxides that had been incorporated into the kaolinitic clays before firing. Batch adsorption tests indicate increased sorption and inactivation of surrogate viruses by media amended with Fe and Al oxide, with FeOOH-amended ceramic inactivating all bacteriophages up to 8 log10. Unmodified ceramic was a poor adsorbent of bacteriophages at less than 1 log10 adsorption-inactivation and high recovery of sorbed phages. These studies suggest that contact with ceramic media, modified with electropositive Fe or Al oxides, can reduce bacteriophages in waters to a greater extent than unmodified ceramic.

  19. Characterization of dense lead lanthanum titanate ceramics prepared from powders synthesized by the oxidant peroxo method

    Energy Technology Data Exchange (ETDEWEB)

    Pinto, Alexandre H. [LIEC-Laboratorio Interdisciplinar de Eletroquimica e Ceramica, Departamento de Quimica, UFSCar-Universidade Federal de Sao Carlos, Rod.Washington Luis km 235, CP 676 Sao Carlos, SP 13565-905 (Brazil); Souza, Flavio L., E-mail: flavio.souza@ufabc.edu.br [Centro de Ciencias Naturais e Humanas, Universidade Federal do ABC, Rua Santa Adelia 166, Bangu, Santo Andre, SP 09210-170 (Brazil); Chiquito, Adenilson J., E-mail: chiquito@df.ufscar.br [Departamento de Fisica, UFSCar-Federal University of Sao Carlos, Rod.Washington Luis km 235, CP 676 Sao Carlos, SP 13565-905 (Brazil); Longo, Elson, E-mail: elson@iq.unesp.br [Instituto de Quimica de Araraquara, UNESP-Universidade Estadual Paulista, Rua Francisco Degni, CP 355 Araraquara, SP 14801-907 (Brazil); Leite, Edson R., E-mail: derl@power.ufscar.br [LIEC-Laboratorio Interdisciplinar de Eletroquimica e Ceramica, Departamento de Quimica, UFSCar-Universidade Federal de Sao Carlos, Rod.Washington Luis km 235, CP 676 Sao Carlos, SP 13565-905 (Brazil); Camargo, Emerson R., E-mail: camargo@ufscar.br [LIEC-Laboratorio Interdisciplinar de Eletroquimica e Ceramica, Departamento de Quimica, UFSCar-Universidade Federal de Sao Carlos, Rod.Washington Luis km 235, CP 676 Sao Carlos, SP 13565-905 (Brazil)

    2010-12-01

    Nanosized powders of lead lanthanum titanate (Pb{sub 1-x}La{sub x}TiO{sub 3}) were synthesized by means of the oxidant-peroxo method (OPM). Lanthanum was added from 5 to 30% in mol through the dissolution of lanthanum oxide in nitric acid, followed by the addition of lead nitrate to prepare a solution of lead and lanthanum nitrates, which was dripped into an aqueous solution of titanium peroxo complexes, forming a reactive amorphous precipitate that could be crystallized by heat treatment. Crystallized powders were characterized by FT-Raman spectroscopy and X-ray powder diffraction, showing that tetragonal perovskite structure is obtained for samples up to 25% of lanthanum and cubic perovskite for samples with 30% of lanthanum. Powders containing 25 and 30% in mol of lanthanum were calcined at 700 deg. C for 2 h, and in order to determine the relative dielectric permittivity and the phase transition behaviour from ferroelectric-to-paraelectric, ceramic pellets were prepared and sintered at 1100 or 1150 deg. C for 2 h and subjected to electrical characterization. It was possible to observe that sample containing 25% in mol of La presented a normal behaviour for the phase transition, whereas the sample containing 30% in mol of La presented a diffuse phase transition and relaxor behaviour.

  20. Characterization of dense lead lanthanum titanate ceramics prepared from powders synthesized by the oxidant peroxo method

    International Nuclear Information System (INIS)

    Pinto, Alexandre H.; Souza, Flavio L.; Chiquito, Adenilson J.; Longo, Elson; Leite, Edson R.; Camargo, Emerson R.

    2010-01-01

    Nanosized powders of lead lanthanum titanate (Pb 1-x La x TiO 3 ) were synthesized by means of the oxidant-peroxo method (OPM). Lanthanum was added from 5 to 30% in mol through the dissolution of lanthanum oxide in nitric acid, followed by the addition of lead nitrate to prepare a solution of lead and lanthanum nitrates, which was dripped into an aqueous solution of titanium peroxo complexes, forming a reactive amorphous precipitate that could be crystallized by heat treatment. Crystallized powders were characterized by FT-Raman spectroscopy and X-ray powder diffraction, showing that tetragonal perovskite structure is obtained for samples up to 25% of lanthanum and cubic perovskite for samples with 30% of lanthanum. Powders containing 25 and 30% in mol of lanthanum were calcined at 700 deg. C for 2 h, and in order to determine the relative dielectric permittivity and the phase transition behaviour from ferroelectric-to-paraelectric, ceramic pellets were prepared and sintered at 1100 or 1150 deg. C for 2 h and subjected to electrical characterization. It was possible to observe that sample containing 25% in mol of La presented a normal behaviour for the phase transition, whereas the sample containing 30% in mol of La presented a diffuse phase transition and relaxor behaviour.

  1. Study of the phase composition of nanostructures produced by the local anodic oxidation of titanium films

    International Nuclear Information System (INIS)

    Avilov, V. I.; Ageev, O. A.; Konoplev, B. G.; Smirnov, V. A.; Solodovnik, M. S.; Tsukanova, O. G.

    2016-01-01

    The results of experimental studies of the phase composition of oxide nanostructures formed by the local anodic oxidation of a titanium thin film are reported. The data of the phase analysis of titanium-oxide nanostructures are obtained by X-ray photoelectron spectroscopy in the ion profiling mode of measurements. It is established that the surface of titanium-oxide nanostructures 4.5 ± 0.2 nm in height possesses a binding energy of core levels characteristic of TiO_2 (458.4 eV). By analyzing the titanium-oxide nanostructures in depth by X-ray photoelectron spectroscopy, the formation of phases with binding energies of core levels characteristic of Ti_2O_3 (456.6 eV) and TiO (454.8 eV) is established. The results can be used in developing the technological processes of the formation of a future electronic-component base for nanoelectronics on the basis of titanium-oxide nanostructures and probe nanotechnologies.

  2. W-containing oxide layers obtained on aluminum and titanium by PEO as catalysts in thiophene oxidation

    Science.gov (United States)

    Rudnev, V. S.; Lukiyanchuk, I. V.; Vasilyeva, M. S.; Morozova, V. P.; Zelikman, V. M.; Tarkhanova, I. G.

    2017-11-01

    W-containing oxide layers fabricated on titanium and aluminum alloys by Plasma electrolytic oxidation (PEO) have been tested in the reaction of the peroxide oxidation of thiophene. Samples with two types of coatings have been investigated. Coatings I contained tungsten oxide in the matrix and on the surface of amorphous silica-titania or silica-alumina layers, while coatings II comprised crystalline WO3 and/or Al2(WO4)3. Aluminum-supported catalyst containing a smallest amount of transition metals in the form of tungsten oxides and manganese oxides in low oxidation levels showed high activity and stability.

  3. Formation of pyridine N-oxides using mesoporous titanium silicalite-1

    DEFF Research Database (Denmark)

    Mielby, Jerrik Jørgen; Abildstrøm, Jacob Oskar; Perez-Ferreras, Susana

    2014-01-01

    Mesoporous titanium silicalite-1 (TS-1) prepared by carbon-templating is significantly more active than conventional TS-1 for the oxidation of pyridine derivatives using aqueous hydrogen peroxide as oxidant. The catalytic activity is increased by the system of mesopores that helps to overcome the...

  4. "A New Class of Creep Resistant Oxide/Oxide Ceramic Matrix Composites"

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Mohit Jain, Dr. Ganesh Skandan, Prof. Roger Cannon, Rutgers University

    2007-03-30

    Despite recent progress in the development of SiC-SiC ceramic matrix composites (CMCs), their application in industrial gas turbines for distributed energy (DE) systems has been limited. The poor oxidation resistance of the non-oxide ceramics warrants the use of envrionmental barrier coatings (EBCs), which in turn lead to issues pertaining to life expectancy of the coatings. On the other hand, oxide/oxide CMCs are potential replacements, but their use has been limited until now due to the poor creep resistance at high temperatures, particularly above 1200 oC: the lack of a creep resistant matrix has been a major limiting factor. Using yttrium aluminum garnet (YAG) as the matrix material system, we have advanced the state-of-the-art in oxide/oxide CMCs by introducing innovations in both the structure and composition of the matrix material, thereby leading to high temperature matrix creep properties not achieved until now. An array of YAG-based powders with a unique set of particle characteristics were produced in-house and sintered to full density and compressive creep data was obtained. Aided in part by the composition and the microstructure, the creep rates were found to be two orders of magnitude smaller than the most creep resistant oxide fiber available commercially. Even after accounting for porosity and a smaller matrix grain size in a practical CMC component, the YAG-based matrix material was found to creep slower than the most creep resistant oxide fiber available commercially.

  5. The Otto Aufranc Award: Enhanced Biocompatibility of Stainless Steel Implants by Titanium Coating and Microarc Oxidation

    Science.gov (United States)

    Lim, Young Wook; Kwon, Soon Yong; Sun, Doo Hoon

    2010-01-01

    Background Stainless steel is one of the most widely used biomaterials for internal fixation devices, but is not used in cementless arthroplasty implants because a stable oxide layer essential for biocompatibility cannot be formed on the surface. We applied a Ti electron beam coating, to form oxide layer on the stainless steel surface. To form a thicker oxide layer, we used a microarc oxidation process on the surface of Ti coated stainless steel. Modification of the surface using Ti electron beam coating and microarc oxidation could improve the ability of stainless steel implants to osseointegrate. Questions/purposes The ability of cells to adhere to grit-blasted, titanium-coated, microarc-oxidated stainless steel in vitro was compared with that of two different types of surface modifications, machined and titanium-coated, and microarc-oxidated. Methods We performed energy-dispersive x-ray spectroscopy and scanning electron microscopy investigations to assess the chemical composition and structure of the stainless steel surfaces and cell morphology. The biologic responses of an osteoblastlike cell line (SaOS-2) were examined by measuring proliferation (cell proliferation assay), differentiation (alkaline phosphatase activity), and attraction ability (cell migration assay). Results Cell proliferation, alkaline phosphatase activity, migration, and adhesion were increased in the grit-blasted, titanium-coated, microarc-oxidated group compared to the two other groups. Osteoblastlike cells on the grit-blasted, titanium-coated, microarc-oxidated surface were strongly adhered, and proliferated well compared to those on the other surfaces. Conclusions The surface modifications we used (grit blasting, titanium coating, microarc oxidation) enhanced the biocompatibility (proliferation and migration of osteoblastlike cells) of stainless steel. Clinical Relevance This process is not unique to stainless steel; it can be applied to many metals to improve their biocompatibility

  6. The oxidation of titanium nitride- and silicon nitride-coated stainless steel in carbon dioxide environments

    International Nuclear Information System (INIS)

    Mitchell, D.R.G.; Stott, F.H.

    1992-01-01

    A study has been undertaken into the effects of thin titanium nitride and silicon nitride coatings, deposited by physical vapour deposition and chemical vapour deposition processes, on the oxidation resistance of 321 stainless steel in a simulated advanced gas-cooled reactor carbon dioxide environment for long periods at 550 o C and 700 o C under thermal-cycling conditions. The uncoated steel contains sufficient chromium to develop a slow-growing chromium-rich oxide layer at these temperatures, particularly if the surfaces have been machine-abraded. Failure of this layer in service allows formation of less protective iron oxide-rich scales. The presence of a thin (3-4 μm) titanium nitride coating is not very effective in increasing the oxidation resistance since the ensuing titanium oxide scale is not a good barrier to diffusion. Even at 550 o C, iron oxide-rich nodules are able to develop following relatively rapid oxidation and breakdown of the coating. At 700 o C, the coated specimens oxidize at relatively similar rates to the uncoated steel. A thin silicon nitride coating gives improved oxidation resistance, with both the coating and its slow-growing oxide being relatively electrically insulating. The particular silicon nitride coating studied here was susceptible to spallation on thermal cycling, due to an inherently weak coating/substrate interface. (Author)

  7. Topotactic reduction yielding black titanium oxide nanostructures as metallic electronic conductors.

    Science.gov (United States)

    Tominaka, Satoshi

    2012-10-01

    Detailed analyses of reduced, single crystal, rutile-type TiO(2) via high-resolution transmission electron microscopy (TEM) are reported which reveal that the reduction proceeds topotactically via interstitial diffusion of Ti ions at low temperature, around 350 °C. This important finding encouraged the production of various nanostructured reduced titanium oxides from TiO(2) precursors with morphology retention, and in the process, the synthesis of black titanium oxide nanorods using TiO(2) nanorods was demonstrated. Interestingly, as opposed to the semiconductive behavior of Ti(2)O(3) synthesized at high temperature, topotactically synthesized Ti(2)O(3) exhibits metallic electrical resistance, and the value at room temperature is quite low (topotactically synthesized Ti(2)O(3). This work shows that topotactically reduced titanium oxides can have fascinating properties as well as nanostructures.

  8. Isolation and characterisation of barium sulphate and titanium oxides in monument crusts

    Energy Technology Data Exchange (ETDEWEB)

    Luis Perez-Rodriguez, Jose; Carmen Jimenez de Haro, Maria del; Maqueda, Celia

    2004-10-25

    Black crusts from historical ornamental materials contain Ba and Ti. These elements are in low proportion, making their determination difficult and especially the characterisation of the phases in which they are present. For this reason, works on the mineralogical composition of the two elements in black crusts is scarce. Thus the isolation, previous to their characterisation, is important for the study of the surface layer in altered monuments. An acid attack for the isolation of barium sulphate and titanium oxides in black crusts from polluted areas has been used. The acid employed is a mixture of HF, HNO{sub 3} and HClO{sub 4}. The residue isolated by acid attack was analysed by energy dispersive X-ray fluorescence and X-ray diffraction. It was characterised, and the percentages of barite (barium sulphate), anatase (titanium oxide), and rutile (titanium oxide) phases present in the surface layers were calculated.

  9. Characterization of Titanium Oxide Nanoparticles Obtained by Hydrolysis Reaction of Ethylene Glycol Solution of Alkoxide

    Directory of Open Access Journals (Sweden)

    Naofumi Uekawa

    2012-01-01

    Full Text Available Transparent and stable sols of titanium oxide nanoparticles were obtained by heating a mixture of ethylene glycol solution of titanium tetraisopropoxide (TIP and a NH3 aqueous solution at 368 K for 24 h. The concentration of NH3 aqueous solution affected the structure of the obtained titanium oxide nanoparticles. For NH3 aqueous solution concentrations higher than 0.2 mol/L, a mixture of anatase TiO2 nanoparticles and layered titanic acid nanoparticles was obtained. The obtained sol was very stable without formation of aggregated precipitates and gels. Coordination of ethylene glycol to Ti4+ ions inhibited the rapid hydrolysis reaction and aggregation of the obtained nanoparticles. The obtained titanium oxide nanoparticles had a large specific surface area: larger than 350 m2/g. The obtained titanium oxide nanoparticles showed an enhanced adsorption towards the cationic dye molecules. The selective adsorption corresponded to presence of layered titanic acid on the obtained anatase TiO2 nanoparticles.

  10. Electrocontact material based on silver dispersion-strengthened by nickel, titanium, and zinc oxides

    Science.gov (United States)

    Zeer, G. M.; Zelenkova, E. G.; Belousov, O. V.; Beletskii, V. V.; Nikolaev, S. V.; Ledyaeva, O. N.

    2017-09-01

    Samples of a composite electrocontact material based on silver strengthened by the dispersed phases of zinc and titanium oxides have been investigated by the electron microscopy and energy dispersive X-ray spectroscopy. A uniform distribution of the oxide phases containing 2 wt % zinc oxide in the initial charge has been revealed. The increase in the amount of zinc oxide leads to an increase of the size of the oxide phases. It has been shown that at the zinc oxide content of 2 wt %, the minimum wear is observed in the process of electroerosion tests; at 3 wt %, an overheating and welding of the contacts are observed.

  11. Dual-energy CT and ceramic or titanium prostheses material reduce CT artifacts and provide superior image quality of total knee arthroplasty.

    Science.gov (United States)

    Kasparek, Maximilian F; Töpker, Michael; Lazar, Mathias; Weber, Michael; Kasparek, Michael; Mang, Thomas; Apfaltrer, Paul; Kubista, Bernd; Windhager, Reinhard; Ringl, Helmut

    2018-06-07

    To evaluate the influence of different scan parameters for single-energy CT and dual-energy CT, as well as the impact of different material used in a TKA prosthesis on image quality and the extent of metal artifacts. Eight pairs of TKA prostheses from different vendors were examined in a phantom set-up. Each pair consisted of a conventional CoCr prosthesis and the corresponding anti-allergic prosthesis (full titanium, ceramic, or ceramic-coated) from the same vendor. Nine different (seven dual-energy CT and two single-energy CT) scan protocols with different characteristics were used to determine the most suitable CT protocol for TKA imaging. Quantitative image analysis included assessment of blooming artifacts (metal implants appear thicker on CT than they are, given as virtual growth in mm in this paper) and streak artifacts (thick dark lines around metal). Qualitative image analysis was used to investigate the bone-prosthesis interface. The full titanium prosthesis and full ceramic knee showed significantly fewer blooming artifacts compared to the standard CoCr prosthesis (mean virtual growth 0.6-2.2 mm compared to 2.9-4.6 mm, p energy CT protocols showed less blooming (range 3.3-3.8 mm) compared to single-energy protocols (4.6-5.5 mm). The full titanium and full ceramic prostheses showed significantly fewer streak artifacts (mean standard deviation 77-86 Hounsfield unit (HU)) compared to the standard CoCr prosthesis (277-334 HU, p energy CT protocols had fewer metal streak artifacts (215-296 HU compared to single-energy CT protocols (392-497 HU)). Full titanium and ceramic prostheses were ranked superior with regard to the image quality at the bone/prosthesis interface compared to a standard CoCr prosthesis, and all dual-energy CT protocols were ranked better than single-energy protocols. Dual-energy CT and ceramic or titanium prostheses reduce CT artifacts and provide superior image quality of total knee arthroplasty at the bone/prosthesis interface

  12. Reduction-oxidation Enabled Glass-ceramics to Stainless Steel Bonding Part I: screening of doping oxidants

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Steve Xunhu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    Lithium silicate-based glass-ceramics with high coefficients of thermal expansion, designed to form matched hermetic seals in 304L stainless steel housing, show little evidence of interfacial chemical bonding, despite extensive inter-diffusion at the glass-ceramic-stainless steel (GC-SS) interface. A series of glass-ceramic compositions modified with a variety of oxidants, AgO, FeO, NiO, PbO, SnO, CuO, CoO, MoO3 and WO3, are examined for the feasibility of forming bonding oxides through reduction-oxidation (redox) at the GC-SS interface. The oxidants were selected according to their Gibbs free energy to allow for oxidation of Cr/Mn/Si from stainless steel, and yet to prevent a reduction of P2O5 in the glass-ceramic where the P2O5 is to form Li3PO4 nuclei for growth of high expansion crystalline SiO2 phases. Other than the CuO and CoO modified glass-ceramics, bonding from interfacial redox reactions were not achieved in the modified glass-ceramics, either because of poor wetting on the stainless steel or a reduction of the oxidants at the surface of glass-ceramic specimens rather than the GC-SS interface.

  13. Ceramic membrane as a pretreatment for reverse osmosis: Interaction between marine organic matter and metal oxides

    KAUST Repository

    Dramas, Laure

    2013-02-01

    Scaling and (bio)fouling phenomena can severely alter the performance of the reverse osmosis process during desalination of seawater. Pretreatments must be applied to efficiently remove particles, colloids, and also precursors of the organic fouling and biofouling. Ceramic membranes offer a lot of advantages for micro and ultrafiltration pretreatments because their initial properties can be recovered using more severe cleaning procedure. The study focuses on the interaction between metal oxides and marine organic matter. Experiments were performed at laboratory scale. The first series of experiments focus on the filtration of different fractions of natural organic matter and model compounds solutions on flat disk ceramic membranes (47 mm of diameter) characterized with different pore size and composition. Direct filtration experiments were conducted at 0.7 bar or 2 bars and at room temperature (20 ± 0.5 °C). The efficiency of backflush and alkaline cleaning were eval, and titanium oxides. Each metal oxide corresponds to a specific pore size for the disk ceramic membranes: 80, 60, and 30 nm. Different sizes of metal oxide particles are used to measure the impact of the surface area on the adsorption of the organic matter. Seawaters from the Arabian Gulf and from the Red Sea were collected during algal blooms. Cultures of algae were also performed in the laboratory and in cooperation with woods hole oceanographic institute. Solutions of algal exudates were obtained after a couple of weeks of cultivation followed by sonication. Solutions were successively filtered through GFF (0.7 lm) and 0.45 lm membrane filters before use. The dissolved organic carbon (DOC) concentration of final solution was between 1 and 4 mg/L and showed strong hydrophilic character. These various solutions were prepared with the objective to mimic the dissolved organic matter composition of seawater subjected to algal bloom. Characterization of the solutions of filtration experiments (feed

  14. Solid ceramic based on mixed-frame titanium phosphate and calcium synthesized in solar furnace

    International Nuclear Information System (INIS)

    Salikhov, T. P.; Kan, V. V.; Urazaeva, Eh. M.; Savatyugina, T. V.; Arushanov, G. M.

    2012-01-01

    The authors synthesized of mixed orthophosphates Ca 0 . 5 Ti 2 (PO 4 ) 3 using concentrated solar radiation. We obtained a porous ceramic filter with the given type of NZP structure and high thermal and hydrolytic stability. (authors)

  15. Phases quantification in titanium oxides by means of X-ray diffraction

    International Nuclear Information System (INIS)

    Macias B, L.R.; Garcia C, R.M.; Ita T, A. de; Chavez R, A.

    2001-01-01

    In this work two phases of titanium oxides are quantified which belong to the same crystalline system and by means of a computer program named Quanto created by the first author, contains the information for calculating the absorption coefficients, it can be quantified phases having one of the pure phases and the problem samples. In order to perform this work different mixtures of different titanium oxides were prepared measuring by means of the X-ray diffraction technique in the Siemens X-ray diffractometer of ININ which were processed with the Peakfit package and also they were evaluated by means of the computer program with the necessary information finding acceptable results. (Author)

  16. Photocatalytic Oxidation of a Volatile Organic Component of Acetaldehyde Using Titanium Oxide Nanotubes

    Directory of Open Access Journals (Sweden)

    Yifeng Wang

    2007-01-01

    Full Text Available Titanium oxide nanotubes are prepared and treated with Au (Au/nanotube sample and Pt (Pt/nanotube sample, and the photoactivity of these catalysts compared to a standard Degussa P25 photocatalyst is investigated. The samples were analyzed using X-ray diffraction, field emission gun scanning transmission electron microscopy (STEM. Both high-resolution TEM images and high-angle annular dark-field (HAAD images were recorded for the specimens. Oxidation of acetaldehyde was used to test the efficiency of the catalysts. Nanotube samples showed better photoactivity than the standard P25, because the P25 titania deactivates quickly. Enhanced reactivity of the nanotube is related to surface charge polarity developed on outer and inner surfaces due to the difference in overlap of oxygen anions that resulted from curving of octahedral sheets. A tentative and qualitative surface polarity model is proposed for enhancing electron-hole pair separation. The inner surface benefits reduction; whereas, the outer surface benefits oxidation reactions. Both the metal identity and the size of the metal particles in the nanotubes affected the photocatalytic activity. Specifically, the addition of platinum increased the activity significantly, and increased the total yield. The addition of gold had lesser impact compared to the platinum. Formation of Pt large nanoparticles on the nanotube surfaces reduces the oxidation reactivity.

  17. Chemical composition and morphology of oxidic ceramics at filtration of steel deoxidised by aluminium

    Directory of Open Access Journals (Sweden)

    J. Bažan

    2009-10-01

    Full Text Available Composition and morphology of filter ceramics were investigated during filtration of steel deoxidised by aluminium. Filtration was realized with use of filters based on oxidic ceramics Cr2O3, TiO2, SiO2, ZrO2, Al2O3, 3Al2O3•2SiO2 and MgO•Al2O3. It was established that change of interphase (coating occurs during filtration of steel on the surface of capillaries of ceramics, where content of basic oxidic component decreases. Loss of oxidic component in the coating is replaced by increase of oxides of manganese and iron and it is great extent inversely proportional to the value of Gibbs’ energy of oxide, which forms this initial basis of ceramics.

  18. Inactivation of Escherichia coli by titanium dioxide photocatalytic oxidation.

    Science.gov (United States)

    Titanium dioxide in the anatase crystalline form was used as a photocatalyst to generate hydroxyl radicals in a flowthrough water reactor. Experiments were performed on pure cultures of Escherichia coli in dechlorinated tap water and a surface water sample to evaluate the disinfe...

  19. One-Piece Zirconia Ceramic versus Titanium Implants in the Jaw and Femur of a Sheep Model: A Pilot Study.

    Science.gov (United States)

    Siddiqi, A; Duncan, W J; De Silva, R K; Zafar, S

    2016-01-01

    Reports have documented titanium (Ti) hypersensitivity after dental implant treatment. Alternative materials have been suggested including zirconia (Zr) ceramics, which have shown predictable osseointegration in animal studies and appear free of immune responses. The aim of the research was to investigate the bone-to-implant contact (BIC) of one-piece Zr, compared with one-piece Ti implants, placed in the jaws and femurs of domestic sheep. Ten New Zealand mixed breed sheep were used. A One-piece prototype Ti (control) and one Zr (test) implant were placed in the mandible, and one of each implant (Ti and Zr) was placed into the femoral epicondyle of each animal. The femur implants were submerged and unloaded; the mandibular implants were placed using a one-stage transgingival protocol and were nonsubmerged. After a healing period of 12 weeks, %BIC was measured. The overall survival rate for mandibular and femur implants combined was 87.5%. %BIC was higher for Zr implants versus Ti implants in the femur (85.5%, versus 78.9%) ( p = 0.002). Zirconia implants in the mandible showed comparable %BIC to titanium implants (72.2%, versus 60.3%) ( p = 0.087). High failure rate of both Zr and Ti one-piece implants in the jaw could be attributed to the one-piece design and surface characteristics of the implant that could have influenced osseointegration. Further clinical trials are recommended to evaluate the performance of zirconia implants under loading conditions.

  20. Anisotropy oxidation of textured ZrB2–MoSi2 ceramics

    DEFF Research Database (Denmark)

    Liu, Hai-Tao; Zou, Ji; Ni, De Wei

    2012-01-01

    Oxidation behavior of hot forged textured ZrB2–20vol% MoSi2 ceramics with platelet ZrB2 grains was investigated at 1500°C for exposure time from 0.5 to 12h. Compared to untextured ceramics, the textured ceramics showed obvious anisotropic oxidation behavior and the surface normal to the hot forgi...

  1. Assessment of full ceramic solid oxide fuel cells based on modified strontium titanates

    DEFF Research Database (Denmark)

    Holtappels, Peter; Ramos, Tania; Sudireddy, Bhaskar Reddy

    2014-01-01

    stimulated the development for full ceramic anodes based on strontium titanates. Furthermore, the Ni-cermet is primarily a hydrogen oxidation electrode and efficiency losses might occur when operating on carbon containing fuels. In the European project SCOTAS-SOFC full ceramic cells comprising CGO...

  2. Localized and collectivized behaviour of d-electrons in complicated titanium, vanadium and niobium oxides

    International Nuclear Information System (INIS)

    Bazuev, G.V.; Shvejkin, G.P.

    1980-01-01

    On the basis of investigation of electric and magnetic properties of oxide compounds of transition metals made are the conclusions on the degree of localization and delocalization of d-electrons in them. Generalized are the investigation results of complicated titanium, vanadium, niobium oxide compounds in low degrees of oxidation with rare earth and alkaline earth elements belonging to the two structural types: perovskite and pyrochlore. Presented are the results of investigations of perovskite-like solid solutions and of variable-content phases containing cations of transition metals in two different oxidation degrees: oxide niobium bronzes of two-valent europium and titanium bronzes of rare-earth elements, as well as Lnsub(1-x)Msub(x)Vsub(1-x)sup(3+)Vsub(x)sup(4+)Osub(3), where M is an alkaline earth element

  3. Effect of metal selection and porcelain firing on the marginal accuracy of titanium-based metal ceramic restorations.

    Science.gov (United States)

    Shokry, Tamer E; Attia, Mazen; Mosleh, Ihab; Elhosary, Mohamed; Hamza, Tamer; Shen, Chiayi

    2010-01-01

    Titanium is the most biocompatible metal used for dental casting; however, there is concern about its marginal accuracy after porcelain application since this aspect has direct influence on marginal fit. The purpose of this study was to determine the effect that metal selection and the porcelain firing procedure have on the marginal accuracy of metal ceramic prostheses. Cast CP Ti, milled CP Ti, cast Ti-6Al-7Nb, and cast Ni-Cr copings (n=5) were fired with compatible porcelains (Triceram for titanium-based metals and VITA VMK 95 for Ni-Cr alloy). The Ni-Cr alloy fired with its porcelain served as the control. Photographs of metal copings placed on a master die were made. Marginal discrepancy was determined on the photographs using an image processing program at 8 predetermined locations before airborne-particle abrasion for porcelain application, after firing of the opaque layer, and after firing of the dentin layer. Repeated-measures 2-way ANOVA was used to investigate the effect of metal selection and firing stage, and paired t tests were used to determine the effect of each firing stage within each material group (alpha=.05). ANOVA showed that both metal selection and firing stage significantly influenced the measured marginal discrepancy (Pcast Ti-6Al-7Nb alloy (P=.003). Titanium copings fabricated by CAD/CAM demonstrated the least marginal discrepancy among all groups, while the base metal (Ni-Cr) groups exhibited the most discrepancy of all groups tested. Copyright 2010 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

  4. Titanium Oxide/Platinum Catalysis: Charge Transfer from a Titanium Oxide Support Controls Activity and Selectivity in Methanol Oxidation on Platinum

    KAUST Repository

    Hervier, Antoine

    2011-11-24

    Platinum films of 1 nm thickness were deposited by electron beam evaporation onto 100 nm thick titanium oxide films (TiOx) with variable oxygen vacancy concentrations and fluorine (F) doping. Methanol oxidation on the platinum films produced formaldehyde, methyl formate, and carbon dioxide. F-doped samples demonstrated significantly higher activity for methanol oxidation when the TiOx was stoichiometric (TiO 2), but lower activity when it was nonstoichiometric (TiO 1.7 and TiO1.9). These results correlate with the chemical behavior of the same types of catalysts in CO oxidation. Fluorine doping of stoichiometric TiO2 also increased selectivity toward partial oxidation of methanol to formaldehyde and methyl formate, but had an opposite effect in the case of nonstoichiometric TiOx. Introduction of oxygen vacancies and fluorine doping both increased the conductivity of the TiO x film. For oxygen vacancies, this occurred by the formation of a conduction channel in the band gap, whereas in the case of fluorine doping, F acted as an n-type donor, forming a conduction channel at the bottom of the conduction band, about 0.5-1.0 eV higher in energy. The higher energy electrons in F-doped stoichiometric TiOx led to higher turnover rates and increased selectivity toward partial oxidation of methanol. This correlation between electronic structure and turnover rate and selectivity indicates that the ability of the support to transfer charges to surface species controls in part the activity and selectivity of the reaction. © 2011 American Chemical Society.

  5. Progress in the characterisation of structural oxide/oxide ceramic matrix composites fabricated by electrophoretic deposition (EPD)

    Czech Academy of Sciences Publication Activity Database

    Stoll, E.; Mahr, P.; Kruger, H. G.; Kern, H.; Dlouhý, Ivo; Boccaccini, A. R.

    2006-01-01

    Roč. 8, č. 4 (2006), s. 282-285 ISSN 1438-1656 R&D Projects: GA ČR(CZ) GA106/05/0495 Institutional research plan: CEZ:AV0Z20410507 Keywords : electorphoretic deposition * oxid/oxid ceramic matrix composites * flexural strength Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 1.402, year: 2006 http://www3.interscience.wiley.com/cgi-bin/jissue/112579545

  6. Oxochloroalkoxide of the Cerium (IV and Titanium (IV as oxides precursor

    Directory of Open Access Journals (Sweden)

    Machado Luiz Carlos

    2002-01-01

    Full Text Available The Cerium (IV and Titanium (IV oxides mixture (CeO2-3TiO2 was prepared by thermal treatment of the oxochloroisopropoxide of Cerium (IV and Titanium (IV. The chemical route utilizing the Cerium (III chloride alcoholic complex and Titanium (IV isopropoxide is presented. The compound Ce5Ti15Cl16O30 (iOPr4(OH-Et15 was characterized by elemental analysis, FTIR and TG/DTG. The X-ray diffraction patterns of the oxides resulting from the thermal decomposition of the precursor at 1000 degreesC for 36 h indicated the formation of cubic cerianite (a = 5.417Å and tetragonal rutile (a = 4.592Å and (c = 2.962 Å, with apparent crystallite sizes around 38 and 55nm, respectively.

  7. Phase constituents and microstructure of laser cladding Al2O3/Ti3Al reinforced ceramic layer on titanium alloy

    International Nuclear Information System (INIS)

    Li Jianing; Chen Chuanzhong; Lin Zhaoqing; Squartini, Tiziano

    2011-01-01

    Research highlights: → In this study, Fe 3 Al has been chosen as cladding powder due to its excellent properties of wear resistance and high strength, etc. → Laser cladding of Fe 3 Al + TiB 2 /Al 2 O 3 pre-placed alloy powder on Ti-6Al-4V alloy substrate can form the Ti 3 Al/Fe 3 Al + TiB 2 /Al 2 O 3 ceramic layer, which can increase wear resistance of substrate. → In cladding process, Al 2 O 3 can react with TiB 2 leading to formation of Ti 3 Al and B. → This principle can be used to improve the Fe 3 Al + TiB 2 laser-cladded coating. - Abstract: Laser cladding of the Fe 3 Al + TiB 2 /Al 2 O 3 pre-placed alloy powder on Ti-6Al-4V alloy can form the Ti 3 Al/Fe 3 Al + TiB 2 /Al 2 O 3 ceramic layer, which can greatly increase wear resistance of titanium alloy. In this study, the Ti 3 Al/Fe 3 Al + TiB 2 /Al 2 O 3 ceramic layer has been researched by means of electron probe, X-ray diffraction, scanning electron microscope and micro-analyzer. In cladding process, Al 2 O 3 can react with TiB 2 leading to formation of amount of Ti 3 Al and B. This principle can be used to improve the Fe 3 Al + TiB 2 laser cladded coating, it was found that with addition of Al 2 O 3 , the microstructure performance and micro-hardness of the coating was obviously improved due to the action of the Al-Ti-B system and hard phases.

  8. Catalytic properties of a titanium-antimony oxide system in oxidative ammonolysis of propylene

    Energy Technology Data Exchange (ETDEWEB)

    Zenkovets, G.A.; Tarasova, D.V.; Andrushkevich, T.V.; Aleshina, G.I.; Nikoro, T.A.; Ravilov, R.G.

    1979-03-01

    The catalytic properties of titanium-antimony oxide system in oxidative ammonolysis of propylene at 450/sup 0/C depended both on the catalyst and the reactant compositions. Stable and high (75-80Vertical Bar3<) selectivities for acrylonitrile and high activities were observed over catalysts containing 5-60 mole Vertical Bar3< Sb/sub 2/O/sub 4/ with 2Vertical Bar3< propylene and 3Vertical Bar3< ammonia in air at Vertical Bar3; 70Vertical Bar3< conversions. The selectivities of the catalysts for acetonitrile and acrolein did not exceed 5 and 1Vertical Bar3<, respectively. At high ammonia and propylene contents in the reaction mixture and over individual TiO/sub 2/ or Sb/sub 2/O/sub 4/ catalysts, the reaction selectivity shifted toward deep oxidation products. These findings were attributed to the reducing effect of propylene and ammonia at high concentrations on the active components of the catalyst, a solid solution of Sb in TiO/sub 2/ containing 5-7 mole Vertical Bar3< of Sb/sub 2/O/sub 4/ and a chemical compound with TiSb/sub 2/O/sub 6/ composition.

  9. Highly n-Type Titanium Oxide as an Electronically Active Support for Platinum in the Catalytic Oxidation of Carbon Monoxide

    KAUST Repository

    Baker, L. Robert

    2011-08-18

    The role of the oxide-metal interface in determining the activity and selectivity of chemical reactions catalyzed by metal particles on an oxide support is an important topic in science and industry. A proposed mechanism for this strong metal-support interaction is electronic activation of surface adsorbates by charge carriers. Motivated by the goal of using electronic activation to drive nonthermal chemistry, we investigated the ability of the oxide support to mediate charge transfer. We report an approximately 2-fold increase in the turnover rate of catalytic carbon monoxide oxidation on platinum nanoparticles supported on stoichiometric titanium dioxide (TiO2) when the TiO2 is made highly n-type by fluorine (F) doping. However, for nonstoichiometric titanium oxide (TiOX<2) the effect of F on the turnover rate is negligible. Studies of the titanium oxide electronic structure show that the energy of free electrons in the oxide determines the rate of reaction. These results suggest that highly n-type TiO2 electronically activates adsorbed oxygen (O) by electron spillover to form an active O- intermediate. © 2011 American Chemical Society.

  10. Study of aluminium oxide from high-alumina refractory ceramics by ...

    Indian Academy of Sciences (India)

    Wintec

    Keywords. Ceramics; aluminium oxide; X-ray diffraction; scanning electron microscopy; thermolumi- nescence. ... and ruby, consists of a slightly distorted hexagonal O. 2– .... a very complex structure consisting of a broad distribu- .... Imax (a.u.).

  11. Template-assisted hydrothermally synthesized iron-titanium binary oxides and their application as catalysts for ethyl acetate oxidation

    Czech Academy of Sciences Publication Activity Database

    Tsoncheva, T.; Ivanova, R.; Dimitrov, M.; Paneva, D.; Kovacheva, D.; Henych, Jiří; Vomáčka, Petr; Kormunda, M.; Velinov, N.; Mitov, I.; Štengl, Václav

    2016-01-01

    Roč. 528, NOV (2016), s. 24-35 ISSN 0926-860X R&D Projects: GA MŠk(CZ) LM2015073 Institutional support: RVO:61388980 Keywords : Effect of Fe/Ti ratio and temperature of hydrothermal treatment * Hydrothermal synthesis * Iron-titanium binary oxides Subject RIV: CA - Inorganic Chemistry Impact factor: 4.339, year: 2016

  12. Electropolymerization of polyaniline on titanium oxide nanotubes for supercapacitor application

    International Nuclear Information System (INIS)

    Mujawar, Sarfraj H.; Ambade, Swapnil B.; Battumur, T.; Ambade, Rohan B.; Lee, Soo-Hyoung

    2011-01-01

    Highlights: → Polyaniline (PANI)-Titanium nanotube template (TNT) composite for supercapacitors. → The mechanism of the controlled growth of hollow open ended PANI nanotubes using a TNT template is studied. → A rare effort to electropolymerise PANI on TNTs resulting into an appreciable capacitance of 740 F g -1 . - Abstract: Vertically aligned polyaniline (PANI) nanotubes have great potential application in supercapacitor electrode material. In this paper we have investigated facile growth of PANI nanotubes on a titanium nanotube template (TNT) using electrochemical polymerization. The morphology of PANI nanostructures grown over TNT is strongly influenced by the scan rate in the electrochemical polymerization. The growth morphology of PANI nanotubes has been carefully analyzed by field emission scanning electron microscopy. The detailed growth mechanism of PANI nanotubes has been put forward. Specific capacitance value of 740 F g -1 was obtained for PANI nanotube structures (measured at charge-discharge rate of 3 A g -1 ).

  13. Electrical characterization of strontium titanate borosilicate glass ceramics system with bismuth oxide addition using impedance spectroscopy

    International Nuclear Information System (INIS)

    Thakur, O.P.; Kumar, Devendra; Parkash, Om; Pandey, Lakshman

    2003-01-01

    The ac electrical data, measured in the frequency range 0.1 kHz-1 MHz, were used to study the electrical response of strontium titanate borosilicate glass ceramic system with bismuth oxide addition. Complex plane plots from these electrical data for various glass ceramic samples reveal contributions from simultaneously operating polarization mechanisms to overall dielectric behavior. The complex modulus (M * ) representation of electrical data for various glass ceramic samples were found to be more informative. Equivalent circuit models, which represent the electrical behavior of glass ceramic samples, were determined using complex non-linear least square (CNLS) fitting. An attempt has been made to understand the dielectric behavior of various glass ceramics in terms of contributions arising from different polarization processes occurring at glassy matrix, crystalline phases, glass to crystal interface region and blocking electrodes. Glass ceramics containing SrTiO 3 and TiO 2 (rutile) phases show thermally stable dielectric behavior

  14. Non thermal preparation of photoactive titanium (IV) oxide thin layers

    Czech Academy of Sciences Publication Activity Database

    Klusoň, P.; Lusková, H.; Cajthaml, Tomáš; Šolcová, Olga

    2006-01-01

    Roč. 495, - (2006), s. 18-23 ISSN 0040-6090 R&D Projects: GA ČR GA104/04/0963; GA ČR GD203/03/H140; GA MPO FT-TA/023 Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z40720504 Keywords : titanium dioxide * nanostructures * photocatalysis Subject RIV: EE - Microbiology, Virology Impact factor: 1.666, year: 2006

  15. Electrorheological properties of suspensions of hollow globular titanium oxide/polypyrrole particles

    Czech Academy of Sciences Publication Activity Database

    Sedlačík, M.; Mrlík, M.; Pavlínek, V.; Sáha, P.; Quadrat, Otakar

    2012-01-01

    Roč. 290, č. 1 (2012), s. 41-48 ISSN 0303-402X R&D Projects: GA ČR GA202/09/1626 Institutional research plan: CEZ:AV0Z40500505 Keywords : electrorheology * titanium oxide * hollow globular clusters Subject RIV: JI - Composite Materials Impact factor: 2.161, year: 2012

  16. Electrical properties of vacuum-annealed titanium-doped indium oxide films

    NARCIS (Netherlands)

    Yan, L.T.; Rath, J.K.; Schropp, R.E.I.

    2011-01-01

    Titanium-doped indium oxide (ITiO) films were deposited on Corning glass 2000 substrates at room temperature by radio frequency magnetron sputtering followed by vacuum post-annealing. With increasing deposition power, the as-deposited films showed an increasingly crystalline nature. As-deposited

  17. Nano-thick calcium oxide armed titanium: boosts bone cells against methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Cao, Huiliang; Qin, Hui; Zhao, Yaochao; Jin, Guodong; Lu, Tao; Meng, Fanhao; Zhang, Xianlong; Liu, Xuanyong

    2016-02-22

    Since the use of systemic antibiotics for preventing acute biomaterial-associated infections (BAIs) may build up bacterial resistance and result in huge medical costs and unpredictable mortality, new precaution strategies are required. Here, it demonstrated that titanium armed with a nano-thick calcium oxide layer was effective on averting methicillin-resistant Staphylococcus aureus (MRSA) infections in rabbits. The calcium oxide layer was constructed by, firstly, injecting of metallic calcium into titanium via a plasma immersion ion implantation process, and then transforming the outer most surface into oxide by exposing to the atmosphere. Although the calcium oxide armed titanium had a relative low reduction rate (~74%) in growth of MRSA in vitro, it could markedly promote the osteogenic differentiation of bone marrow stem cells (BMSCs), restore local bone integration against the challenge of MRSA, and decrease the incidence of MRSA infection with a rate of 100% (compared to the titanium control). This study demonstrated for the first time that calcium, as one of the major elements in a human body, could be engineered to avert MRSA infections, which is promising as a safe precaution of disinfection for implantable biomedical devices.

  18. Comparison of various methods of measuring thin oxide layers formed on molybdenum and titanium

    International Nuclear Information System (INIS)

    Lepage, F.; Bardolle, J.; Boulben, J.M.

    1975-01-01

    The problem of the growth of thin layers is very interesting from both the fundamental and technological viewpoints. This work deals with oxide films produced on two metals, molybdenum and titanium. The thicknesses obtained by various methods (microgravimetry, nuclear reactions and spectrophotometry) are compared and the advantages and disadvantages of each method are shown [fr

  19. Tuning the Electronic Structure of Titanium Oxide Support to Enhance the Electrochemical Activity of Platinum Nanoparticles

    KAUST Repository

    Shi, Feifei; Baker, L. Robert; Hervier, Antoine; Somorjai, Gabor A.; Komvopoulos, Kyriakos

    2013-01-01

    on pristine TiO2 support were achieved by tuning the electronic structure of the titanium oxide support of Pt nanoparticle catalysts. This was accomplished by adding oxygen vacancies or doping with fluorine. Experimental trends are interpreted in the context

  20. Transmission Electron Microscopy Studies of Electron-Selective Titanium Oxide Contacts in Silicon Solar Cells

    KAUST Repository

    Ali, Haider; Yang, Xinbo; Weber, Klaus; Schoenfeld, Winston V.; Davis, Kristopher O.

    2017-01-01

    In this study, the cross-section of electron-selective titanium oxide (TiO2) contacts for n-type crystalline silicon solar cells were investigated by transmission electron microscopy. It was revealed that the excellent cell efficiency of 21

  1. Phenotypic and genomic responses to titanium dioxide and cerium oxide nanoparticles in Arabidopsis germinants

    Science.gov (United States)

    The effects of exposure to two nanoparticles (NPs) -titanium dioxide (nano-titania) and cerium oxide (nano-ceria) at 500 mg NPs L-1 on gene expression and growth in Arabidopsis thaliana germinants were studied using microarrays and phenotype studies. After 12 days post treatment,...

  2. Nano-thick calcium oxide armed titanium: boosts bone cells against methicillin-resistant Staphylococcus aureus

    Science.gov (United States)

    Cao, Huiliang; Qin, Hui; Zhao, Yaochao; Jin, Guodong; Lu, Tao; Meng, Fanhao; Zhang, Xianlong; Liu, Xuanyong

    2016-02-01

    Since the use of systemic antibiotics for preventing acute biomaterial-associated infections (BAIs) may build up bacterial resistance and result in huge medical costs and unpredictable mortality, new precaution strategies are required. Here, it demonstrated that titanium armed with a nano-thick calcium oxide layer was effective on averting methicillin-resistant Staphylococcus aureus (MRSA) infections in rabbits. The calcium oxide layer was constructed by, firstly, injecting of metallic calcium into titanium via a plasma immersion ion implantation process, and then transforming the outer most surface into oxide by exposing to the atmosphere. Although the calcium oxide armed titanium had a relative low reduction rate (~74%) in growth of MRSA in vitro, it could markedly promote the osteogenic differentiation of bone marrow stem cells (BMSCs), restore local bone integration against the challenge of MRSA, and decrease the incidence of MRSA infection with a rate of 100% (compared to the titanium control). This study demonstrated for the first time that calcium, as one of the major elements in a human body, could be engineered to avert MRSA infections, which is promising as a safe precaution of disinfection for implantable biomedical devices.

  3. Synthesis and characterization of nanocomposite powders of calcium phosphate/titanium oxide for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Delima, S.A.; Camargo, N.H.A.; Souza, J.C.P.; Gemelli, E., E-mail: sarahamindelima@hotmail.com, E-mail: dem2nhac@joinville.udesc.br, E-mail: souzajulio@joinville.udesc.br, E-mail: gemelli@joinville.udesc.br [Universidade do Estado de Santa Catarina (UDESC), Joinville, SC (Brazil). Centro de Ciencias Tecnologicas

    2009-07-01

    The nanostructured bioceramics of calcium phosphate are current themes of research and they are becoming important as bone matrix in regeneration of tissues in orthopedic and dental applications. Nanocomposite powders of calcium phosphate, reinforced with nanometric particles of titanium oxide, silica oxide and alumina oxid ealpha, are being widely studied because they offer new microstructures, nanostructures and interconnected microporosity with high superficial area of micropores that contribute to osteointegration and osteoinduction processes. This study is about the synthesis of nanocomposites powders of calcium phosphate reinforced with 1%, 2%, 3% and 5% in volume of titanium oxide and its characterization through the techniques of X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Differential Thermal Analysis (DTA), Thermogravimetry (TG) and Dilatometry. (author)

  4. Synthesis and characterization of nanocomposite powders of calcium phosphate/titanium oxide for biomedical applications

    International Nuclear Information System (INIS)

    Delima, S.A.; Camargo, N.H.A.; Souza, J.C.P.; Gemelli, E.

    2009-01-01

    The nanostructured bioceramics of calcium phosphate are current themes of research and they are becoming important as bone matrix in regeneration of tissues in orthopedic and dental applications. Nanocomposite powders of calcium phosphate, reinforced with nanometric particles of titanium oxide, silica oxide and alumina oxid ealpha, are being widely studied because they offer new microstructures, nanostructures and interconnected microporosity with high superficial area of micropores that contribute to osteointegration and osteoinduction processes. This study is about the synthesis of nanocomposites powders of calcium phosphate reinforced with 1%, 2%, 3% and 5% in volume of titanium oxide and its characterization through the techniques of X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Differential Thermal Analysis (DTA), Thermogravimetry (TG) and Dilatometry. (author)

  5. 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

  6. Applicability assessment of ceramic microbeads coated with hydroxyapatite-binding silver/titanium dioxide ceramic composite earthplus™ to the eradication of Legionella in rainwater storage tanks for household use.

    Science.gov (United States)

    Oana, Kozue; Kobayashi, Michiko; Yamaki, Dai; Sakurada, Tsukasa; Nagano, Noriyuki; Kawakami, Yoshiyuki

    2015-01-01

    Water environments appear to be the habitats of Legionella species. Legionellosis is considered as a preventable illness because bacterial reservoirs can be controlled and removed. Roof-harvested rainwater has attracted significant attention not only as a groundwater recharge but also as a potential alternative source of nonpotable water. We successfully developed ceramic microbeads coated with hydroxyapatite-binding silver/titanium dioxide ceramic composite earthplus™ using the thermal spraying method. The ceramic microbeads were demonstrated to have bactericidal activities against not only Legionella but also coliform and heterotrophic bacteria. Immersing the ceramic microbeads in household rainwater storage tanks was demonstrated to yield the favorable eradication of Legionella organisms. Not only rapid-acting but also long-lasting bactericidal activities of the ceramic microbead were exhibited against Legionella pneumophila. However, time-dependent attenuation of the bactericidal activities against Legionella were also noted in the sustainability appraisal experiment. Therefore, the problems to be overcome surely remain in constantly managing the Legionella-pollution by means of immersing the ceramic microbeads. The results of our investigation apparently indicate that the earthplus™-coated ceramic microbeads would become the favorable tool for Legionella measures in household rainwater storage tanks, which may become the natural reservoir for Legionella species. Our investigation would justify further research and data collection to obtain more reliable procedures to microbiologically regulate the Legionella in rainwater storage tanks.

  7. Applicability assessment of ceramic microbeads coated with hydroxyapatite-binding silver/titanium dioxide ceramic composite earthplus™ to the eradication of Legionella in rainwater storage tanks for household use

    Science.gov (United States)

    Oana, Kozue; Kobayashi, Michiko; Yamaki, Dai; Sakurada, Tsukasa; Nagano, Noriyuki; Kawakami, Yoshiyuki

    2015-01-01

    Water environments appear to be the habitats of Legionella species. Legionellosis is considered as a preventable illness because bacterial reservoirs can be controlled and removed. Roof-harvested rainwater has attracted significant attention not only as a groundwater recharge but also as a potential alternative source of nonpotable water. We successfully developed ceramic microbeads coated with hydroxyapatite-binding silver/titanium dioxide ceramic composite earthplus™ using the thermal spraying method. The ceramic microbeads were demonstrated to have bactericidal activities against not only Legionella but also coliform and heterotrophic bacteria. Immersing the ceramic microbeads in household rainwater storage tanks was demonstrated to yield the favorable eradication of Legionella organisms. Not only rapid-acting but also long-lasting bactericidal activities of the ceramic microbead were exhibited against Legionella pneumophila. However, time-dependent attenuation of the bactericidal activities against Legionella were also noted in the sustainability appraisal experiment. Therefore, the problems to be overcome surely remain in constantly managing the Legionella-pollution by means of immersing the ceramic microbeads. The results of our investigation apparently indicate that the earthplus™-coated ceramic microbeads would become the favorable tool for Legionella measures in household rainwater storage tanks, which may become the natural reservoir for Legionella species. Our investigation would justify further research and data collection to obtain more reliable procedures to microbiologically regulate the Legionella in rainwater storage tanks. PMID:26346201

  8. A method for the densification of ceramic layers, especially ceramic layers within solid oxide cell (SOC) technology, and products obtained by the method

    DEFF Research Database (Denmark)

    2013-01-01

    A ceramic layer, especially for use in solid oxide cell (SOC) technology, is densified in a method comprising (a) providing a multilayer system by depositing the porous ceramic layer, which is to be densified, onto the selected system of ceramic layers on a support, (b) pre-sintering the resulting......(s) in the porous layer surface and (e) performing a thermal treatment at a temperature T2, where T2 > ?1, to obtain densification of and grain growth in the porous layer formed in step (b). The method makes it possible to obtain dense ceramic layers at temperatures, which are compatible with the other materials...... present in a ceramic multilayer system....

  9. Effect of Prior Exposure at Elevated Temperatures on Tensile Properties and Stress-Strain Behavior of Three Oxide/Oxide Ceramic Matrix Composites

    Science.gov (United States)

    2015-03-26

    observations on the fracture surface using an optical microscope and SEM. 4 II. Background 2.1 Ceramics Ceramics are inorganic and nonmetallic... The original uses for ceramic were primarily decorative, until more utilitarian purposes were discovered. Pottery was developed around 9,000...OF THREE OXIDE/OXIDE CERAMIC MATRIX COMPOSITES THESIS Christopher J. Hull, Captain, USAF AFIT-ENY-MS-15-M-228 DEPARTMENT OF THE AIR FORCE

  10. [Influence of coping material selection and porcelain firing on marginal and internal fit of computer-aided design/computer- aided manufacturing of zirconia and titanium ceramic implant-supported crowns].

    Science.gov (United States)

    Cuiling, Liu; Liyuan, Yang; Xu, Gao; Hong, Shang

    2016-06-01

    This study aimed to investigate the influence of coping material and porcelain firing on the marginal and internal fit of computer-aided design/computer-aided manufacturing (CAD/CAM) of zirconia ceramic implant- and titanium ceramic implant-supported crowns. Zirconia ceramic implant (group A, n = 8) and titanium metal ceramic implant-supported crowns (group B, n = 8) were produced from copings using the CAD/CAM system. The marginal and internal gaps of the copings and crowns were measured by using a light-body silicone replica technique combined with micro-computed tomography scanning to obtain a three-dimensional image. Marginal gap (MG), horizontal marginal discrepancy (HMD), and axial wall (AW) were measured. Statistical analyses were performed using SPSS 17.0. Prior to porcelain firing, the measurements for MG, HMD, and AW of copings in group A were significantly larger than those in group B (P 0.05). Porcelain firing significantly reduced MG (P 0.05). The marginal fits of CAD/CAM zirconia ceramic implant-supported crowns were superior to those of CAD/CAM titanium ceramic-supported crowns. The fits of both the CAD/CAM zirconia ceramic implant- and titanium ceramic implant-supported crowns were obviously influenced by porcelain firing.

  11. Clean forming of stainless steel and titanium products by lubricious oxides

    DEFF Research Database (Denmark)

    Heikkilä, Irma; Wadman, Boel; Thoors, Håkan

    2012-01-01

    to industrial forming processes. Preliminary evaluations show a beneficial influence of two oxides types, on stainless steel and on titanium. More work is needed to test the lubricating effect in other forming operations and to analyse the sustainability aspects for products manufactured with this alternative......Big social benefits can be attained through increased use of stainless steel or titanium in new sheet metal applications. Unfortunately, forming of these materials is often a challenging and costly operation, that can lead to environmental and health problems when solving the technical limitations...

  12. Kinetics of the oxidation of Ba2YCu3O/sub x/ ceramics

    International Nuclear Information System (INIS)

    O'Bryan, H.M.; Gallagher, P.K.

    1988-01-01

    The kinetics of the oxidation of dense and porous samples of Ba 2 YCu 3 O/sub x/ ceramic have been determined by gravimetric analysis at 400--700 0 C. At 600 0 C and above, the rate decreases as the thickness of the oxidized layer increases. At 500 0 C and below, the kinetics show a linear relation that indicates that the oxidized layer does not protect the ceramic. Dilatometric, microscopic, and high-temperature x-ray data suggest that fractures in the oxide layer at the lower temperatures are caused by the large volume decrease that accompanies the change in oxygen stoichiometry

  13. Micro-Arc Oxidation Enhances the Blood Compatibility of Ultrafine-Grained Pure Titanium

    Directory of Open Access Journals (Sweden)

    Lin Xu

    2017-12-01

    Full Text Available Ultrafine-grained pure titanium prepared by equal-channel angular pressing has favorable mechanical performance and does not contain alloy elements that are toxic to the human body. It has potential clinical value in applications such as cardiac valve prostheses, vascular stents, and hip prostheses. To overcome the material’s inherent thrombogenicity, surface-coating modification is a crucial pathway to enhancing blood compatibility. An electrolyte solution of sodium silicate + sodium polyphosphate + calcium acetate and the micro-arc oxidation (MAO technique were employed for in situ oxidation of an ultrafine-grained pure titanium surface. A porous coating with anatase- and rutile-phase TiO2 was generated and wettability and blood compatibility were examined. The results showed that, in comparison with ultrafine-grained pure titanium substrate, the MAO coating had a rougher surface, smaller contact angles for distilled water and higher surface energy. MAO modification effectively reduced the hemolysis rate; extended the dynamic coagulation time, prothrombin time (PT, and activated partial thromboplastin time (APTT; reduced the amount of platelet adhesion and the degree of deformation; and enhanced blood compatibility. In particular, the sample with an oxidation time of 9 min possessed the highest surface energy, largest PT and APTT values, smallest hemolysis rate, less platelet adhesion, a lesser degree of deformation, and more favorable blood compatibility. The MAO method can significantly enhance the blood compatibility of ultrafine-grained pure titanium, increasing its potential for practical applications.

  14. Determination of the thermodynamic properties of titanium sponge, rare earth oxides and carbonates

    International Nuclear Information System (INIS)

    Russo, V.L.; Ivanov, E.N.

    1977-01-01

    The procedure is described of determining heat physical properties of titanium sponge in media controlled at temperatures up to approximately 1100 deg C obtained in an industrial apparatus. The study has been conducted with a sample located into a glass made from stainless steel; the temperature has been measured in the center and near the surface of the sample. The relationships are given between the relative heat conductivity of the titanium sponge, argon pressure and temperature, as well as between a change in heat physical constants of the titanium sponge and temperature. An artificial reaction mass has been created, and the effect of magnesium and magnesium chloride on heat physical properties has been studied. It has been established that heat conductivity for the reaction mass with magnesium chloride is much lower than that of the sponge with magnesium. Heat physical constants of oxides and carbonates of rare-earth elements are given determined with the use of the method developed

  15. Determination of the thermodynamic properties of titanium sponge, rare earth oxides and carbonates

    Energy Technology Data Exchange (ETDEWEB)

    Russo, V L; Ivanov, E N

    1977-03-01

    The procedure is described of determining heat physical properties of titanium sponge in media controlled at temperatures up to approximately 1100/sup 0/C obtained in an industrial apparatus. The study has been conducted with a sample located into a glass made from stainless steel; the temperature has been measured in the center and near the surface of the sample. The relationships are given between the relative heat conductivity of the titanium sponge, argon pressure and temperature, as well as between a change in heat physical constants of the titanium sponge and temperature. An artificial reaction mass has been created, and the effect of magnesium and magnesium chloride on heat physical properties has been studied. It has been established that heat conductivity for the reaction mass with magnesium chloride is much lower than that of the sponge with magnesium. Heat physical constants of oxides and carbonates of rare-earth elements are given determined with the use of the method developed.

  16. Calcium phosphate glass-ceramics for bioactive coating on a β-titanium alloy

    International Nuclear Information System (INIS)

    Kasuga, T.; Nogami, M.; Niinomi, M.

    2003-01-01

    The formation of a porous coating is the decisive feature for the bio-compatibility of silica-free calcium phosphate glass ceramics on alloy surfaces like the β-Ti structured Ti-29Nb-13Ta-4.6Zr used in this work. The ceramic composition is highly important: 50CaO-40P 2 O 5 -7Na 2 O-3TiO 2 glass powder produces a pore-free coating unable to bind hydroxyapatite, whereas 60CaO-30P 2 O 5 -7Na 2 O-3TiO 2 glass incorporates pores from which a crystalline hydroxyapatite phase can grow over the surface from simulated body fluid (see Figure). (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  17. Calcium phosphate glass-ceramics for bioactive coating on a {beta}-titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kasuga, T.; Nogami, M. [Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Niinomi, M. [Department of Production Systems Engineering, Toyohashi University of Technology, Tenpaku-cho, Toyohashi 441-8580 (Japan)

    2003-07-01

    The formation of a porous coating is the decisive feature for the bio-compatibility of silica-free calcium phosphate glass ceramics on alloy surfaces like the {beta}-Ti structured Ti-29Nb-13Ta-4.6Zr used in this work. The ceramic composition is highly important: 50CaO-40P{sub 2}O{sub 5}-7Na{sub 2}O-3TiO{sub 2} glass powder produces a pore-free coating unable to bind hydroxyapatite, whereas 60CaO-30P{sub 2}O{sub 5}-7Na{sub 2}O-3TiO{sub 2} glass incorporates pores from which a crystalline hydroxyapatite phase can grow over the surface from simulated body fluid (see Figure). (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  18. Calcium titanium silicate based glass-ceramic for nuclear waste immobilisation

    Science.gov (United States)

    Sharma, K.; Srivastav, A. P.; Goswami, M.; Krishnan, Madangopal

    2018-04-01

    Titanate based ceramics (synroc) have been studied for immobilisation of nuclear wastes due to their high radiation and thermal stability. The aim of this study is to synthesis glass-ceramic with stable phases from alumino silicate glass composition and study the loading behavior of actinides in glass-ceramics. The effects of CaO and TiO2 addition on phase evolution and structural properties of alumino silicate based glasses with nominal composition x(10CaO-9TiO2)-y(10Na2O-5 Al2O3-56SiO2-10B2O3); where z = x/y = 1.4-1.8 are reported. The glasses are prepared by melt-quench technique and characterized for thermal and structural properties using DTA and Raman Spectroscopy. Glass transition and peak crystallization temperatures decrease with increase of CaO and TiO2 content, which implies the weakening of glass network and increased tendency of glasses towards crystallization. Sphene (CaTiSiO5) and perovskite (CaTiO3) crystalline phases are confirmed from XRD which are well known stable phase for conditioning of actinides. The microsturcture and elemental analysis indicate the presence of actinide in stable crystalline phases.

  19. Direct dynamic synthesis of nanodispersed phases of titanium oxides upon sputtering of electrodischarge titanium plasma into an air atmosphere

    Science.gov (United States)

    Sivkov, A. A.; Gerasimov, D. Yu.; Nikitin, D. S.

    2017-01-01

    Experimental investigations of the possibility of directly synthesizing nanodispersed crystalline phases of titanium dioxides with rutile and anatase structures in a hypervelocity jet of electroerosion plasma generated by a coaxial magnetoplasma accelerator with titanium electrodes are presented. A powder product containing nanosized polymorphic phases of titanium dioxide with a spherical shape of particles has been manufactured.

  20. Conduction and stability of holmium titanium oxide thin films grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Castán, H., E-mail: helena@ele.uva.es [Department of Electronic, University of Valladolid, 47011 Valladolid (Spain); García, H.; Dueñas, S.; Bailón, L. [Department of Electronic, University of Valladolid, 47011 Valladolid (Spain); Miranda, E. [Departament d' Enginyería Electrònica, Universitat Autónoma de Barcelona, 08193 Bellaterra (Spain); Kukli, K. [Department of Chemistry, University of Helsinki, FI-00014 Helsinki (Finland); Institute of Physics, University of Tartu, EE-50411,Tartu (Estonia); Kemell, M.; Ritala, M.; Leskelä, M. [Department of Chemistry, University of Helsinki, FI-00014 Helsinki (Finland)

    2015-09-30

    Holmium titanium oxide (HoTiO{sub x}) thin films of variable chemical composition grown by atomic layer deposition are studied in order to assess their suitability as dielectric materials in metal–insulator–metal electronic devices. The correlation between thermal and electrical stabilities as well as the potential usefulness of HoTiO{sub x} as a resistive switching oxide are also explored. It is shown that the layer thickness and the relative holmium content play important roles in the switching behavior of the devices. Cycled current–voltage measurements showed that the resistive switching is bipolar with a resistance window of up to five orders of magnitude. In addition, it is demonstrated that the post-breakdown current–voltage characteristics in HoTiO{sub x} are well described by a power-law model in a wide voltage and current range which extends from the soft to the hard breakdown regimes. - Highlights: • Gate and memory suitabilities of atomic layer deposited holmium titanium oxide. • Holmium titanium oxide exhibits resistive switching. • Layer thickness and holmium content influence the resistive switching. • Low and high resistance regimes follow a power-law model. • The power-law model can be extended to the hard breakdown regime.

  1. A Classical Potential to Model the Adsorption of Biological Molecules on Oxidized Titanium Surfaces.

    Science.gov (United States)

    Schneider, Julian; Ciacchi, Lucio Colombi

    2011-02-08

    The behavior of titanium implants in physiological environments is governed by the thin oxide layer that forms spontaneously on the metal surface and mediates the interactions with adsorbate molecules. In order to study the adsorption of biomolecules on titanium in a realistic fashion, we first build up a model of an oxidized Ti surface in contact with liquid water by means of extensive first-principles molecular dynamics simulations. Taking the obtained structure as reference, we then develop a classical potential to model the Ti/TiOx/water interface. This is based on the mapping with Coulomb and Lennard-Jones potentials of the adsorption energy landscape of single water and ammonia molecules on the rutile TiO2(110) surface. The interactions with arbitrary organic molecules are obtained via standard combination rules to established biomolecular force fields. The transferability of our potential to the case of organic molecules adsorbing on the oxidized Ti surface is checked by comparing the classical potential energy surfaces of representative systems to quantum mechanical results at the level of density functional theory. Moreover, we calculate the heat of immersion of the TiO2 rutile surface and the detachment force of a single tyrosine residue from steered molecular dynamics simulations, finding good agreement with experimental reference data in both cases. As a first application, we study the adsorption behavior of the Arg-Gly-Asp (RGD) peptide on the oxidized titanium surface, focusing particularly on the calculation of the free energy of desorption.

  2. Bismuth oxide based ceramics with improved electrical and mechanical properties: Part II. Structural and mechanical properties

    NARCIS (Netherlands)

    Kruidhof, H.; Seshan, Kulathuiyer; van de Velde, G.M.H.; de Vries, K.J.; Burggraaf, A.J.

    1988-01-01

    Coprecipitation as a method of preparation for bismuth oxides based ceramics yields relatively strong and machineable materials in comparison with the solid state reaction. Compositions within the system (1−x)Bi2O3|xEr2O3 containing up to twenty five mole percent of erbium oxide show a slow

  3. Investigation of the thermophysical properties of oxide ceramic materials at liquid-helium temperatures

    International Nuclear Information System (INIS)

    Taranov, A. V.; Khazanov, E. N.

    2008-01-01

    The main regularities in the transport of thermal phonons in oxide ceramic materials are investigated at liquid-helium temperatures. The dependences of the thermophysical characteristics of ceramic materials on their structural parameters (such as the grain size R, the grain boundary thickness d, and the structure of grain boundaries) are analyzed. It is demonstrated that, in dense coarse-grained ceramic materials with qR>>1 (where q is the phonon wave vector), the grain boundaries and the grain size are the main factors responsible for the thermophysical characteristics of the material at liquid-helium temperatures. A comparative analysis of the thermophysical characteristics of optically transparent ceramic materials based on the Y 3 Al 5 O 12 (YAG) and Y 2 O 3 cubic oxides synthesized under different technological conditions is performed using the proposed criterion

  4. Bacterial Stress and Osteoblast Responses on Graphene Oxide-Hydroxyapatite Electrodeposited on Titanium Dioxide Nanotube Arrays

    Directory of Open Access Journals (Sweden)

    Yardnapar Parcharoen

    2017-01-01

    Full Text Available To develop bone implant material with excellent antibacterial and biocompatible properties, nanotubular titanium surface was coated with hydroxyapatite (HA and graphene oxide (GO. Layer-by-layer deposition was achieved by coating HA on an anodic-grown titanium dioxide nanotube array (ATi with electrolytic deposition, followed by coating with GO using anodic-electrophoretic deposition. The antibacterial activity against both Gram-negative (Escherichia coli and Gram-positive (Staphylococcus aureus bacteria was determined based on the percentage of surviving bacteria and the amount of ribonucleic acid (RNA leakage and correlated with membrane disruption. The oxidative stress induced in both strains of bacteria by GO was determined by cyclic voltammetry and is discussed. Importantly, the antibacterial GO coatings on HA-ATi were not cytotoxic to preosteoblasts and promoted osteoblast proliferation after 5 days and calcium deposition after 21 days in standard cell culture conditions.

  5. Hydroxyapatite coatings produced on commercially pure titanium by micro-arc oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Huang Yong [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Wang Yingjun [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Ning Chengyun [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Nan Kaihui [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Han Yong [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China)

    2007-09-15

    A porous hydroxyapatite (HA) coating on commercially pure titanium was prepared by micro-arc oxidation (MAO) in electrolytic solution containing calcium acetate and {beta}-glycerol phosphate disodium salt pentahydrate ({beta}-GP). The thickness, phase, composition morphology and biocompatibility of the oxide coating were characterized by x-ray diffraction (XRD), electron probe microanalysis (EPMA), scanning electron microscopy (SEM) with an energy dispersive x-ray spectrometer (EDS) and cell culture. The thickness of the MAO film was about 20 {mu}m, and the coating was porous and uneven without any apparent interface to the titanium substrates. The result of XRD showed that the porous coating was made up of HA film. The favorable osteoblast cell affinity gives HA film good biocompatibility. HA coatings are expected to have significant uses for medical applications such as dental implants and artificial bone joints.

  6. Hydroxyapatite coatings produced on commercially pure titanium by micro-arc oxidation.

    Science.gov (United States)

    Huang, Yong; Wang, Yingjun; Ning, Chengyun; Nan, Kaihui; Han, Yong

    2007-09-01

    A porous hydroxyapatite (HA) coating on commercially pure titanium was prepared by micro-arc oxidation (MAO) in electrolytic solution containing calcium acetate and beta-glycerol phosphate disodium salt pentahydrate (beta-GP). The thickness, phase, composition morphology and biocompatibility of the oxide coating were characterized by x-ray diffraction (XRD), electron probe microanalysis (EPMA), scanning electron microscopy (SEM) with an energy dispersive x-ray spectrometer (EDS) and cell culture. The thickness of the MAO film was about 20 microm, and the coating was porous and uneven without any apparent interface to the titanium substrates. The result of XRD showed that the porous coating was made up of HA film. The favorable osteoblast cell affinity gives HA film good biocompatibility. HA coatings are expected to have significant uses for medical applications such as dental implants and artificial bone joints.

  7. Hydroxyapatite coatings produced on commercially pure titanium by micro-arc oxidation

    International Nuclear Information System (INIS)

    Huang Yong; Wang Yingjun; Ning Chengyun; Nan Kaihui; Han Yong

    2007-01-01

    A porous hydroxyapatite (HA) coating on commercially pure titanium was prepared by micro-arc oxidation (MAO) in electrolytic solution containing calcium acetate and β-glycerol phosphate disodium salt pentahydrate (β-GP). The thickness, phase, composition morphology and biocompatibility of the oxide coating were characterized by x-ray diffraction (XRD), electron probe microanalysis (EPMA), scanning electron microscopy (SEM) with an energy dispersive x-ray spectrometer (EDS) and cell culture. The thickness of the MAO film was about 20 μm, and the coating was porous and uneven without any apparent interface to the titanium substrates. The result of XRD showed that the porous coating was made up of HA film. The favorable osteoblast cell affinity gives HA film good biocompatibility. HA coatings are expected to have significant uses for medical applications such as dental implants and artificial bone joints

  8. Bond strength of selected composite resin-cements to zirconium-oxide ceramic

    Science.gov (United States)

    Fons-Font, Antonio; Amigó-Borrás, Vicente; Granell-Ruiz, María; Busquets-Mataix, David; Panadero, Rubén A.; Solá-Ruiz, Maria F.

    2013-01-01

    Objectives: The aim of this study was to evaluate bond strengths of zirconium-oxide (zirconia) ceramic and a selection of different composite resin cements. Study Design: 130 Lava TM cylinders were fabricated. The cylinders were sandblasted with 80 µm aluminium oxide or silica coated with CoJet Sand. Silane, and bonding agent and/or Clearfil Ceramic Primer were applied. One hundred thirty composite cement cylinders, comprising two dual-polymerizing (Variolink II and Panavia F) and two autopolymerizing (Rely X and Multilink) resins were bonded to the ceramic samples. A shear test was conducted, followed by an optical microscopy study to identify the location and type of failure, an electron microscopy study (SEM and TEM) and statistical analysis using the Kruskal-Wallis test for more than two independent samples and Mann-Whitney for two independent samples. Given the large number of combinations, Bonferroni correction was applied (α=0.001). Results: Dual-polymerizing cements provided better adhesion values (11.7 MPa) than the autopolymerizing (7.47 MPa) (p-value M-Wzirconium-oxide ceramic, creating a more rough and retentive surface, thus providing an improved micromechanical interlocking between the cement and the ceramic. Key words:Shear bond strength, silica coating, surface treatment, zirconia ceramics, phosphate monomer. PMID:22926485

  9. Iodine-labelling of albumin and fibrinogen and application in selecting implantable material-titanium oxide

    International Nuclear Information System (INIS)

    Liu Fangyan; Zhou Meiying; Zhang Feng

    1998-01-01

    Human serum albumin and fibrinogen were successfully labelled with 125 I. The labelled proteins were further applied to carry out a background study on the selection of the blood-compatible materials. The protein adsorption of four kinds of titanium oxide film was determined and compared. It was found that Sample B can adsorb more albumin and less fibrinogen than other three samples and hold the adsorbed albumin most stably

  10. Effect of hydrogen on stresses in anodic oxide film on titanium

    International Nuclear Information System (INIS)

    Kim, Joong-Do; Pyun, Su-Il; Seo, Masahiro

    2003-01-01

    Stresses in anodic oxide film on titanium thin film/glass electrode in pH 8.4 borate solution were investigated by a bending beam method. The increases in compressive stress observed with cathodic potential sweeps after formation of anodic oxide film were attributed to the volume expansion due to the compositional change of anodic oxide film from TiO 2 to TiO 2-x (OH) x . The instantaneous responses of changes in stress, Δσ, in the anodic oxide film to potential steps demonstrated the reversible characteristic of the TiO 2-x (OH) x formation reaction. In contrast, the transient feature of Δσ for the titanium without anodic oxide film represented the irreversible formation of TiH x at the metal/oxide interphase. The large difference in stress between with and without the oxide film, has suggested that most of stresses generated during the hydrogen absorption/desorption reside in the anodic oxide film. A linear relationship between changes in stress, Δ(Δσ) des , and electric charge, ΔQ des , during hydrogen desorption was found from the current and stress transients, manifesting that the stress changes were crucially determined by the amount of hydrogen desorbed from the oxide film. The increasing tendency of -Δ(Δσ) des with increasing number of potential steps and film formation potential were discussed in connection with the increase in desorption amount of hydrogen in the oxide film with increasing absorption/desorption cycles and oxide film thickness

  11. Sol-gel prepared active ternary oxide coating on titanium in cathodic protection

    Directory of Open Access Journals (Sweden)

    VLADIMIR V. PANIC

    2007-12-01

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

  12. Manufacturing conditioned roughness and wear of biomedical oxide ceramics for all-ceramic knee implants.

    Science.gov (United States)

    Turger, Anke; Köhler, Jens; Denkena, Berend; Correa, Tomas A; Becher, Christoph; Hurschler, Christof

    2013-08-29

    Ceramic materials are used in a growing proportion of hip joint prostheses due to their wear resistance and biocompatibility properties. However, ceramics have not been applied successfully in total knee joint endoprostheses to date. One reason for this is that with strict surface quality requirements, there are significant challenges with regard to machining. High-toughness bioceramics can only be machined by grinding and polishing processes. The aim of this study was to develop an automated process chain for the manufacturing of an all-ceramic knee implant. A five-axis machining process was developed for all-ceramic implant components. These components were used in an investigation of the influence of surface conformity on wear behavior under simplified knee joint motion. The implant components showed considerably reduced wear compared to conventional material combinations. Contact area resulting from a variety of component surface shapes, with a variety of levels of surface conformity, greatly influenced wear rate. It is possible to realize an all-ceramic knee endoprosthesis device, with a precise and affordable manufacturing process. The shape accuracy of the component surfaces, as specified by the design and achieved during the manufacturing process, has a substantial influence on the wear behavior of the prosthesis. This result, if corroborated by results with a greater sample size, is likely to influence the design parameters of such devices.

  13. 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

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

    Science.gov (United States)

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

    2018-01-01

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

  15. Anodic oxidation of commercially pure titanium for purification of polluted water

    Science.gov (United States)

    Benkafada, Faouzia; Kerdoud, Djahida; Bouchoucha, Ali

    2018-05-01

    Anodisation of pure titanium has been carried out in sulphuric acid solution at potentials ranging from 40 V to 5 days. We studied the parameters influencing the anodic deposition such as acid concentration and anodic periods. Anodic oxides thin films were characterized by X-ray diffraction, cyclic polarization and electrochemical impedance spectroscopy. The I-V curves and electrochemical impedance measurements were carried out in 0.1 N NaOH solution. The results indicated that although the thin films obtained by anodic oxidation are nonstoichiometric, they have an electric behaviour like n-type semiconducting material.

  16. Electrical Transport Ability of Nanostructured Potassium-Doped Titanium Oxide Film

    Science.gov (United States)

    Lee, So-Yoon; Matsuno, Ryosuke; Ishihara, Kazuhiko; Takai, Madoka

    2011-02-01

    Potassium-doped nanostructured titanium oxide films were fabricated using a wet corrosion process with various KOH solutions. The doped condition of potassium in TiO2 was confirmed by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Nanotubular were synthesized at a dopant concentration of 0.27%, these structures disappeared. To investigate the electrical properties of K-doped TiO2, pseudo metal-oxide-semiconductor field-effect transistor (MOSFET) samples were fabricated. The samples exhibited a distinct electrical behavior and p-type characteristics. The electrical behavior was governed by the volume of the dopant when the dopant concentration was 0.18%.

  17. Comparative proteomic analysis of the molecular responses of mouse macrophages to titanium dioxide and copper oxide nanoparticles unravels some toxic mechanisms for copper oxide nanoparticles in macrophages.

    Directory of Open Access Journals (Sweden)

    Sarah Triboulet

    Full Text Available Titanium dioxide and copper oxide nanoparticles are more and more widely used because of their catalytic properties, of their light absorbing properties (titanium dioxide or of their biocidal properties (copper oxide, increasing the risk of adverse health effects. In this frame, the responses of mouse macrophages were studied. Both proteomic and targeted analyses were performed to investigate several parameters, such as phagocytic capacity, cytokine release, copper release, and response at sub toxic doses. Besides titanium dioxide and copper oxide nanoparticles, copper ions were used as controls. We also showed that the overall copper release in the cell does not explain per se the toxicity observed with copper oxide nanoparticles. In addition, both copper ion and copper oxide nanoparticles, but not titanium oxide, induced DNA strands breaks in macrophages. As to functional responses, the phagocytic capacity was not hampered by any of the treatments at non-toxic doses, while copper ion decreased the lipopolysaccharide-induced cytokine and nitric oxide productions. The proteomic analyses highlighted very few changes induced by titanium dioxide nanoparticles, but an induction of heme oxygenase, an increase of glutathione synthesis and a decrease of tetrahydrobiopterin in response to copper oxide nanoparticles. Subsequent targeted analyses demonstrated that the increase in glutathione biosynthesis and the induction of heme oxygenase (e.g. by lovastatin/monacolin K are critical for macrophages to survive a copper challenge, and that the intermediates of the catecholamine pathway induce a strong cross toxicity with copper oxide nanoparticles and copper ions.

  18. Comparative proteomic analysis of the molecular responses of mouse macrophages to titanium dioxide and copper oxide nanoparticles unravels some toxic mechanisms for copper oxide nanoparticles in macrophages.

    Science.gov (United States)

    Triboulet, Sarah; Aude-Garcia, Catherine; Armand, Lucie; Collin-Faure, Véronique; Chevallet, Mireille; Diemer, Hélène; Gerdil, Adèle; Proamer, Fabienne; Strub, Jean-Marc; Habert, Aurélie; Herlin, Nathalie; Van Dorsselaer, Alain; Carrière, Marie; Rabilloud, Thierry

    2015-01-01

    Titanium dioxide and copper oxide nanoparticles are more and more widely used because of their catalytic properties, of their light absorbing properties (titanium dioxide) or of their biocidal properties (copper oxide), increasing the risk of adverse health effects. In this frame, the responses of mouse macrophages were studied. Both proteomic and targeted analyses were performed to investigate several parameters, such as phagocytic capacity, cytokine release, copper release, and response at sub toxic doses. Besides titanium dioxide and copper oxide nanoparticles, copper ions were used as controls. We also showed that the overall copper release in the cell does not explain per se the toxicity observed with copper oxide nanoparticles. In addition, both copper ion and copper oxide nanoparticles, but not titanium oxide, induced DNA strands breaks in macrophages. As to functional responses, the phagocytic capacity was not hampered by any of the treatments at non-toxic doses, while copper ion decreased the lipopolysaccharide-induced cytokine and nitric oxide productions. The proteomic analyses highlighted very few changes induced by titanium dioxide nanoparticles, but an induction of heme oxygenase, an increase of glutathione synthesis and a decrease of tetrahydrobiopterin in response to copper oxide nanoparticles. Subsequent targeted analyses demonstrated that the increase in glutathione biosynthesis and the induction of heme oxygenase (e.g. by lovastatin/monacolin K) are critical for macrophages to survive a copper challenge, and that the intermediates of the catecholamine pathway induce a strong cross toxicity with copper oxide nanoparticles and copper ions.

  19. Formation and Thermal Stability of Large Precipitates and Oxides in Titanium and Niobium Microalloyed Steel

    Institute of Scientific and Technical Information of China (English)

    ZHUO Xiao-jun; WOO Dae-hee; WANG Xin-hua; LEE Hae-geon

    2008-01-01

    As-cast CC slabs of microalloyed steels are prone to surface and sub-surface cracking. Precipitation phenomena in-itiated during solidification reduce ductility at high temperature. The unidirectional solidification unit is employed to sim-ulate the solidification process during continuous casting. Precipitation behavior and thermal stability are systemati-cally investigated. Samples of adding titanium and niobium to steels have been examined using field emission scanning electron microscope (FE-SEM), electron probe X-ray microanalyzer (EPMA), and transmission electron microscope (TEM). It has been found that the addition of titanium and niobium to high-strength low-alloyed (HSLA) steel resuited in undesirable large precipitation in the steels, i. e. , precipitation of large precipitates with various morphologies. The composition of the large precipitates has been determined. The effect of cooling rate on (Ti, Nb)(C, N) precipitate formation is investigated. With increasing the cooling rate, titanium-rich (Ti,Nb)(C, N) precipitates are transformed to niobium-rich (Ti,Nb)(C,N) precipitates. The thermal stability of these large precipitates and oxides have been assessed by carrying out various heat treatments such as holding and quenching from temperature at 800 and 1 200 ℃. It has been found that titanium-rich (Ti,Nb)(C,N) precipitate is stable at about 1 200 ℃ and niobi-um-rich (Ti,Nb)(C,N) precipitate is stable at about 800 ℃. After reheating at 1 200 ℃ for 1 h, (Ca, Mn)S and TiN are precipitated from Ca-Al oxide. However, during reheating at 800 ℃ for 1 h, Ca-Al-Ti oxide in specimens was stable. The thermodynamic calculation of simulating the thermal process is employed. The calculation results are in good agreement with the experimental results.

  20. Application of titanium oxide nanotube films containing gold nanoparticles for the electroanalytical determination of ascorbic acid

    Energy Technology Data Exchange (ETDEWEB)

    Hosseini, Mir Ghasem, E-mail: mg-hosseini@tabrizu.ac.ir; Faraji, Masoud; Momeni, Mohamad Mohsen

    2011-03-31

    Au/TiO{sub 2}/Ti electrodes have been prepared by galvanic deposition of gold particles on TiO{sub 2} nanotube substrates. Titanium oxide nanotubes are fabricated by anodizing titanium foil in a Dimethyl Sulfoxide electrolyte containing fluoride. The scanning electron microscopy results indicated that gold particles are homogeneously deposited on the surface of TiO{sub 2} nanotubes. The TiO{sub 2} layers consist of individual tubes of about 40-80 nm diameters. The electro-catalytic behavior of Au/TiO{sub 2}/Ti and flat gold electrodes for the ascorbic acid electro-oxidation was studied by cyclic voltammetry. The results showed that the flat gold electrode is not suitable for the oxidation of ascorbic acid. However, the Au/TiO{sub 2}/Ti electrodes are shown to possess catalytic activity toward the oxidation reaction. Catalytic oxidation peak current showed a linear dependence on the ascorbic acid concentration and a linear calibration curve is obtained in the concentration range of 1-5 mM of ascorbic acid. Also, determination of ascorbic acid in real samples was evaluated. The obtained results were found to be satisfactory. Finally the effects of interference on the detection of ascorbic acid were investigated.

  1. Synthesis and characterization of nickel oxide doped barium strontium titanate ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, M. [Dept. of Electrical Engineering, Bengal Institute of Technology Kolkata (India); Mukherjee, S. [Dept. of Metallurgical Engineering, Jadavpur University, Kolkata (India); Maitra, S. [Govt. College of Engg. and Ceramic Technology, Kolkata (India)

    2012-01-15

    Barium strontium titanate (BST) ceramics (Ba{sub 0.6}Sr{sub 0.4})TiO{sub 3} were synthesized by solid state sintering using barium carbonate, strontium carbonate and rutile as the precursor materials. The samples were doped with nickel oxide in different proportions. Different phases present in the sintered samples were determined from X-ray diffraction investigation and the distribution of different phases in the microstructure was assessed from scanning electron microscopy study. It was observed that the dielectric properties of BST were modified significantly with nickel oxide doping. These ceramics held promise for applications in tuned circuits. (author)

  2. Tribological performance of titanium samples oxidized by fs-laser radiation, thermal heating, or electrochemical anodization

    Science.gov (United States)

    Kirner, S. V.; Slachciak, N.; Elert, A. M.; Griepentrog, M.; Fischer, D.; Hertwig, A.; Sahre, M.; Dörfel, I.; Sturm, H.; Pentzien, S.; Koter, R.; Spaltmann, D.; Krüger, J.; Bonse, J.

    2018-04-01

    Commercial grade-1 titanium samples (Ti, 99.6%) were treated using three alternative methods, (i) femtosecond laser processing, (ii) thermal heat treatment, and (iii) electrochemical anodization, respectively, resulting in the formation of differently conditioned superficial titanium oxide layers. The laser processing (i) was carried out by a Ti:sapphire laser (pulse duration 30 fs, central wavelength 790 nm, pulse repetition rate 1 kHz) in a regime of generating laser-induced periodic surface structures (LIPSS). The experimental conditions (laser fluence, spatial spot overlap) were optimized in a sample-scanning setup for the processing of several square-millimeters large surface areas covered homogeneously by these nanostructures. The differently oxidized titanium surfaces were characterized by optical microscopy, micro Raman spectroscopy, variable angle spectroscopic ellipsometry, and instrumented indentation testing. The tribological performance was characterized in the regime of mixed friction by reciprocating sliding tests against a sphere of hardened steel in fully formulated engine oil as lubricant. The specific tribological performance of the differently treated surfaces is discussed with respect to possible physical and chemical mechanisms.

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

    Science.gov (United States)

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

    2009-05-01

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

  4. Development of microstructure during sintering and aluminium exposure of titanium diboride ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Pettersen, Gunnar

    1997-12-31

    In the production of aluminium, much less energy need be consumed if an inert, wetted cathode is present in the electrolysis cell. Titanium diboride, TiB{sub 2}, is easily wetted and does not readily dissolve in liquid aluminium, but it degrades, probably because aluminium penetrates into it during electrolysis. This degradation is linked to impurities present in the TiB{sub 2} after sintering. This thesis studies the sintering process and how aluminium penetrates into the material. High-purity, high-density TiB{sub 2} compacts were made by hot pressing at 50 MPa in an argon atmosphere at 1790-1960 {sup o}C. Samples were made with different impurity additions. These samples were exposed to liquid aluminium at 980 {sup o}C for 24 hours. All samples were penetrated, but the amount and appearance depended on the sintering aid used. Unlike the other samples, pure TiB{sub 2} was easily penetrated by metallic aluminium because of the open porosity and microcracks of this material. Grain boundary penetration was common among the samples. Differences in penetration behaviour between grain boundaries are probably due to differences in grain boundary energy. But no relation to segregants or boundary misorientation was found. The orientation of grain boundary planes and de-wetting of thin films upon cooling may explain the observed microstructure development. The samples sintered with Ti addition suffered extensive penetration despite their high densities. The grain boundaries of these samples became faceted and contained thicker films of metallic aluminium, presumably because of increased solubility due to iron segregations. All secondary phases present in the grain junctions after sintering, except from the B{sub 4}C phase, reacted with the penetrated aluminium. This did not cause swelling and cracking, as has been suggested by other authors. 101 refs., 48 figs., 7 tabs.

  5. Reduction-oxidation Enabled Glass-ceramics to Stainless Steel Bonding Part II interfacial bonding analysis

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Steve Xunhu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    Among glass-ceramic compositions modified with a variety of oxidants (AgO, FeO, NiO, PbO, SnO, CuO, CoO, MoO3 and WO3) only CuO and CoO doped glass-ceramics showed existence of bonding oxides through reduction-oxidation (redox) at the GC-SS interface. The CuO-modified glass-ceramics demonstrate the formation of a continuous layer of strong bonding Cr2O3 at the interface in low partial oxygen (PO2) atmosphere. However, in a local reducing atmosphere, the CuO is preferentially reduced at the surface of glass-ceramic rather than the GC-SS interface for redox. The CoO-modified glass-ceramics demonstrate improved GC-SS bonding. But the low mobility of Co++ ions in the GC limited the amount of CoO that can diffuse to and participate in redox at the interface.

  6. Synthesis of self-detached nanoporous titanium-based metal oxide

    International Nuclear Information System (INIS)

    Hu, F.; Wen, Y.; Chan, K.C.; Yue, T.M.; Zhou, Y.Z.; Zhu, S.L.; Yang, X.J.

    2015-01-01

    In this study, self-detached nanoporous titanium-based metal oxide was synthesized for the first time by ultrafast anodization in a fluoride-free electrolyte containing 10% HNO 3 . The nanoporous oxide has through-holes with diameters ranging from 10 to 60 nm. The as-formed oxides are amorphous, and were transformed to crystalline structures by annealing. The performance of a dye sensitized solar cell using nanoporpous Ti–10Zr oxide (TZ10) was further studied. It was found that the TZ10 film could increase both the short-circuit current and the open-circuit photovoltage of the solar cell. The overall efficiency of the solar cell was 6.99%, an increase of 20.7% as compared to that using a pure TiO 2 (P25) film. - Graphical abstract: The nanoporous Ti–xZr(x=10, 30) oxide layers are fabricated by anodizing in a dilute nitric acid solvent. The power conversion efficiency of the DSSC by a covering of a Ti–10Zr thin film is increased by 20.7%, with an η of 7.69% , a short circuit current of 12.4 mA/cm 2 , a open circuit voltage of 0.833 V, and a fill factor of 0.679. - Highlights: • Self-detached nanoporous titanium-based metal (TiZr) oxide was synthesized. • The TiZr oxides have through-hole nanopores with diameters ranging from 10 to 60 nm. • The nanoporous Ti–10Zr oxide can improve the power conversion efficiency of a DSSC

  7. Synthesis of self-detached nanoporous titanium-based metal oxide

    Energy Technology Data Exchange (ETDEWEB)

    Hu, F. [Advanced Manufacturing Technology Research Center, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University (Hong Kong); Jiangxi Key Laboratory of Advanced Ceramic Materials, School of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jiangxi 343001 (China); Wen, Y. [Jiangxi Key Laboratory of Advanced Ceramic Materials, School of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jiangxi 343001 (China); Chan, K.C., E-mail: mfkcchan@inet.polyu.edu.hk [Advanced Manufacturing Technology Research Center, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University (Hong Kong); Yue, T.M. [Advanced Manufacturing Technology Research Center, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University (Hong Kong); Zhou, Y.Z. [Jiangxi Key Laboratory of Advanced Ceramic Materials, School of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jiangxi 343001 (China); Zhu, S.L.; Yang, X.J. [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China)

    2015-09-15

    In this study, self-detached nanoporous titanium-based metal oxide was synthesized for the first time by ultrafast anodization in a fluoride-free electrolyte containing 10% HNO{sub 3}. The nanoporous oxide has through-holes with diameters ranging from 10 to 60 nm. The as-formed oxides are amorphous, and were transformed to crystalline structures by annealing. The performance of a dye sensitized solar cell using nanoporpous Ti–10Zr oxide (TZ10) was further studied. It was found that the TZ10 film could increase both the short-circuit current and the open-circuit photovoltage of the solar cell. The overall efficiency of the solar cell was 6.99%, an increase of 20.7% as compared to that using a pure TiO{sub 2} (P25) film. - Graphical abstract: The nanoporous Ti–xZr(x=10, 30) oxide layers are fabricated by anodizing in a dilute nitric acid solvent. The power conversion efficiency of the DSSC by a covering of a Ti–10Zr thin film is increased by 20.7%, with an η of 7.69% , a short circuit current of 12.4 mA/cm{sup 2}, a open circuit voltage of 0.833 V, and a fill factor of 0.679. - Highlights: • Self-detached nanoporous titanium-based metal (TiZr) oxide was synthesized. • The TiZr oxides have through-hole nanopores with diameters ranging from 10 to 60 nm. • The nanoporous Ti–10Zr oxide can improve the power conversion efficiency of a DSSC.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-07-15

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

  9. Self-cleaning glasses containing nanostructured titanium oxide; Vidros autolimpantes contendo oxido de titanio nanoestruturado

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, A.; Alves, A.K.; Berutti, F.A.; Bergmann, C.P. [Universidade Federal do Rio Grande do Sul (DEMa/UFRGS), Porto Alegre, RS (Brazil). Dept. de Materiais

    2010-07-01

    Using the electrospinning technique nanofibers of titanium oxide were synthesized. As precursor materials, titanium propoxide and a solution of polyvinylpyrrolidone were used. After the electrospinning process, the non-tissue material obtained was heat treated and characterized by X-ray diffraction to determine the phase crystallinity, and SEM to analyze the microstructure of the fibers. After ultrasound dispersion of this material in isopropyl alcohol, the glass coatings were made by dip-coating methodology. The removal velocity was kept constant, but the solution composition was varied to obtain a transparent and photo active film. The film was characterized by the contact angle of a water droplet in its surface (hydrophilicity), the transparency was evaluated using a spectrophotometer and the photocatalytic activity of the film was also evaluated. (author)

  10. The ceramic SiO2 and SiO2-TiO2 coatings on biomedical Ti6Al4VELI titanium alloy

    International Nuclear Information System (INIS)

    Surowska, B.; Walczak, M.; Bienias, J.

    2004-01-01

    The paper presents the study of intermediate SiO 2 and SiO 2 -TiO 2 sol-gel coatings and dental porcelain coatings on Ti6Al4VELI titanium alloy. Surface microstructures and wear behaviour by pin-on-disc method of the ceramic coatings were investigated. The analysis revealed: (1) a compact, homogeneous SiO 2 and SiO 2 -TiO 2 coating and (2) that intermediate coatings may provide a durable joint between metal and porcelain, and (3) that dental porcelain on SiO 2 and TiO 2 coatings shows high wear resistance. (author)

  11. Effect of sintering temperature on the microstructure and properties of foamed glass-ceramics prepared from high-titanium blast furnace slag and waste glass

    Science.gov (United States)

    Chen, Chang-hong; Feng, Ke-qin; Zhou, Yu; Zhou, Hong-ling

    2017-08-01

    Foamed glass-ceramics were prepared via a single-step sintering method using high-titanium blast furnace slag and waste glass as the main raw materials The influence of sintering temperature (900-1060°C) on the microstructure and properties of foamed glass-ceramics was studied. The results show that the crystal shape changed from grainy to rod-shaped and finally turned to multiple shapes as the sintering temperature was increased from 900 to 1060°C. With increasing sintering temperature, the average pore size of the foamed glass-ceramics increased and subsequently decreased. By contrast, the compressive strength and the bulk density decreased and subsequently increased. An excessively high temperature, however, induced the coalescence of pores and decreased the compressive strength. The optimal properties, including the highest compressive strength (16.64 MPa) among the investigated samples and a relatively low bulk density (0.83 g/cm3), were attained in the case of the foamed glass-ceramics sintered at 1000°C.

  12. Influence of aluminium nitride as a foaming agent on the preparation of foam glass-ceramics from high-titanium blast furnace slag

    Science.gov (United States)

    Shi, Huan; Feng, Ke-qin; Wang, Hai-bo; Chen, Chang-hong; Zhou, Hong-ling

    2016-05-01

    To effectively reuse high-titanium blast furnace slag (TS), foam glass-ceramics were successfully prepared by powder sintering at 1000°C. TS and waste glass were used as the main raw materials, aluminium nitride (AlN) as the foaming agent, and borax as the fluxing agent. The influence of the amount of AlN added (1wt%-5wt%) on the crystalline phases, microstructure, and properties of the produced foam glass-ceramics was studied. The results showed that the main crystal phases were perovskite, diopside, and augite. With increasing AlN content, a transformation from diopside to augite occurred and the crystallinity of the pyroxene phases slightly decreased. Initially, the average pore size and porosity of the foam glass-ceramics increased and subsequently decreased; similarly, their bulk density and compressive strength decreased and subsequently increased. The optimal properties were obtained when the foam glass-ceramics were prepared by adding 4wt% AlN.

  13. Obtainment of zirconium oxide and partially stabilized zirconium oxide with yttrium and rare earth oxides, from Brazilian zirconite, for ceramic aim

    International Nuclear Information System (INIS)

    Ribeiro, S.

    1991-05-01

    This work presents experimental results for processing of brazilian zirconite in order to obtain zirconium oxide with Yttrium and Rare Earth oxide by mutual coprecipitation for ceramics purposes. Due to analysis of experimental results was possible to obtain the optimum conditions for each one of technological route stage, such as: alkaline fusion; acid leaching; sulfactation and coprecipitation. (author)

  14. Electric-Loading Enhanced Kinetics in Oxide Ceramics: Pore Migration, Sintering and Grain Growth: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Chen, I-Wei [Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Materials Science & Engineering

    2018-02-02

    Solid oxide fuel cells and solid oxide electrolysis cells rely on solid electrolytes in which a large ionic current dominates. This project was initiated to investigate microstructural changes in such devices under electrochemical forces, because nominally insignificant processes may couple to the large ionic current to yield non-equilibrium phenomena that alter the microstructure. Our studies had focused on yttria-stabilized cubic zirconia (YSZ) widely used in these devices. The experiments have revealed enhanced grain growth at higher temperatures, pore and gas bubble migration at all temperatures, and the latter also lead to enhanced sintering of highly porous ceramics into fully dense ceramics at unprecedentedly low temperatures. These results have shed light on kinetic processes that fall completely outside the realm of classical ceramic processing. Other fast-oxygen oxide ceramics closely related to, and often used in conjunction with zirconia ceramics, have also be investigated, as are closely related scientific problems in zirconia ceramics. These include crystal structures, defects, diffusion kinetics, oxygen potentials, low temperature sintering, flash sintering, and coarsening theory, and all have resulted in greater clarity in scientific understanding. The knowledge is leveraged to provide new insight to electrode kinetics and near-electrode mixed conductivity and to new materials. In the following areas, our research has resulted in completely new knowledge that defines the state-of-the-art of the field. (a) Electrical current driven non-equilibrium phenomena, (b) Enhanced grain growth under electrochemically reducing conditions, (c) Development of oxygen potential polarization in electrically loaded electrolyte, (d) Low temperature sintering and grain growth, and (e) Structure, defects and cation kinetics of fluorite-structured oxides. Our research has also contributed to synthesis of new energy-relevant electrochemical materials and new understanding

  15. Synthesis and characterization of new ceramic thermoelectrics implemented in a thermoelectric oxide module

    Czech Academy of Sciences Publication Activity Database

    Tomeš, P.; Robert, R.; Trottmann, M.; Bocher, L.; Aguirre, M.H.; Bitschi, A.; Hejtmánek, Jiří; Weidenkaff, A.

    2010-01-01

    Roč. 39, č. 9 (2010), 1696-1703 ISSN 0361-5235 Institutional research plan: CEZ:AV0Z10100521 Keywords : thermoelectric materials * perovskites * power generation * oxide ceramics * micro-IR camera measurement Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.421, year: 2010

  16. Re-oxidation phenomena during the filtration of steel by means of ceramic filters

    Czech Academy of Sciences Publication Activity Database

    Stránský, K.; Bažant, J.; Dobrovská, J.; Rek, Antonín; Horáková, D.

    2009-01-01

    Roč. 43, č. 5 (2009), s. 261-265 ISSN 1580-2949 Institutional research plan: CEZ:AV0Z20650511 Keywords : filtration of steel * ceramic filters * capillary tube re-oxidation * micro-cleanliness of steel Subject RIV: JG - Metallurgy Impact factor: 0.143, year: 2009 http://www.imt.si/Revija/izvodi/mit095/stransky.pdf

  17. Effect of binder burnout on the sealing performance of glass ceramics for solid oxide fuel cells

    Science.gov (United States)

    Ertugrul, Tugrul Y.; Celik, Selahattin; Mat, Mahmut D.

    2013-11-01

    The glass ceramics composite sealants are among few materials suitable for the solid oxide fuel cells (SOFC) due to their high operating temperatures (600 °C-850 °C). The glass ceramics chemically bond to both the metallic interconnector and the ceramic electrolyte and provide a gas tight connection. A careful and several stages manufacturing procedure is required to obtain a gas tight sealing. In this study, effects of binder burnout process on the sealing performance are investigated employing commercially available glass ceramic powders. The glass ceramic laminates are produced by mixing glass ceramic powders with the organic binders and employing a tape casting method. The laminates are sandwiched between the metallic interconnectors of an SOFC cell. The burnout and subsequent sealing quality are analyzed by measuring leakage rate and final macrostructure of sealing region. The effects of heating rate, dead weight load, solid loading, carrier gas and their flow rates are investigated. It is found that sealing quality is affected from all investigated parameters. While a slower heating rate is required for a better burnout, the mass flow rate of sweep gas must be adequate for removal of the burned gas. The leakage rate is reduced to 0.1 ml min-1 with 2 °C min-1 + 1 °C min-1 heating rate, 86.25% solid loading, 200 N dead weight load and 500 ml min-1 sweep gas flow rate.

  18. Ternary ceramic alloys of Zr-Ce-Hf oxides

    Science.gov (United States)

    Becher, P.F.; Funkenbusch, E.F.

    1990-11-20

    A ternary ceramic alloy is described which produces toughening of zirconia and zirconia composites through the stress transformation from tetragonal phase to monoclinic phase. This alloy, having the general formula Ce[sub x]Hf[sub y]Zr[sub 1[minus]x[minus]y]O[sub 2], is produced through the addition of appropriate amounts of ceria and hafnia to the zirconia. Typically, improved toughness is achieved with about 5 to about 15 mol % ceria and up to about 40 mol % hafnia. The preparation of alloys of these compositions are given together with data as to the densities, tetragonal phase content, hardness and fracture toughness. The alloys are useful in preparing zirconia bodies as well as reinforcing ceramic composites. 1 fig.

  19. Oxidation studies of β-sialon ceramics containing amorphous and / or crystalline intergranular phases

    International Nuclear Information System (INIS)

    Persson, J.; Kall, P.O.; Jansson, K.; Nygren, M.

    1992-01-01

    β-sialon ceramics of equal overall compositions but containing amorphous, partly crystalline and almost completely crystalline intergranular phase(s) have been oxidized in oxygen at 1350 deg C for 20 hours. The obtained weight gain curves do not follow the parabolic rate law (ΔW/A 0 ) 2 = k p t + β. To the extent that crystallization occurs in the oxide scale during the oxidation experiment, the amorphous cross section area through which oxygen most easily diffuses will decrease with time. A brief description of this new rate law is given, and the obtained oxidation curves will be discussed within that framework. 4 refs., 2 tabs., 2 figs

  20. Composition dependence of the kinetics and mechanisms of thermal oxidation of titanium-tantalum alloys

    International Nuclear Information System (INIS)

    Park, Y.S.; Butt, D.P.

    1999-01-01

    The oxidation behavior of titanium-tantalum alloys was investigated with respective concentrations of each element ranging from 0 to 100 wt.%. Alloys were exposed to argon-20% oxygen at 800 to 1400 C. The slowest oxidation rates were observed in alloys with 5--20% Ta. The oxidation kinetics of alloys containing less than approximately 40% Ta were approximately parabolic. Pure Ta exhibited nearly linear kinetics. Alloys containing 50% or more Ta exhibited paralinear kinetics. The activation energies for oxidation ranged between 232 kJ/mole for pure Ti and 119 kJ/mole for pure Ta, with the activation energies of the alloys falling between these values and generally decreasing with increasing Ta content. The activation energies for oxidation of the end members, Ti and Ta, agree well with published values for the activation energies for diffusion of oxygen in α-Ti and Ta. Scale formation in the alloys was found to be complex exhibiting various layers of Ti-, Ta-, and TiTa-oxides. The outermost layer of the oxidized alloys was predominantly rutile (TiO 2 ). Beneath the TiO 2 grew a variety of other oxides with the Ta content generally increasing with proximity to the metal-oxide interface. It was found that the most oxidation-resistant alloys had compositions falling between Ti-5Ta and Ti-15Ta. Although Ta stabilizes the β-phase of Ti, the kinetics of oxidation appeared to be rate limited by oxygen transport through the oxygen-stabilized α-phase. However, the kinetics are complicated by the formation of a complex oxide, which cracks periodically. Tantalum appears to increase the compositional range of oxygen-stabilized α-phase and reduces both the solubility of oxygen and diffusivity of Ti in the α- and β-phases

  1. Mechanical and tribological property of single layer graphene oxide reinforced titanium matrix composite coating

    Science.gov (United States)

    Hu, Zengrong; Li, Yue; Fan, Xueliang; Chen, Feng; Xu, Jiale

    2018-04-01

    Single layer grapheme oxide Nano sheets and Nano titanium powder were dispersed in deionized water by ultrasonic dispersion. Then the mixed solution was pre-coating on AISI4140 substrate. Using laser sintering process to fabricated grapheme oxide and Ti composite coating. Microstructures and composition of the composite coating was studied by Scanning Electron Microscopy (SEM), x-ray diffract meter (XRD) and Raman spectroscopy. Raman spectrum, XRD pattern and SEM results proved that grapheme oxide sheets were dispersed in the composite coating. The composite coating had much higher average Vickers hardness values than that of pure Ti coating. The tribological performance of the composite coatings became better while the suitable GO content was selected. For the 2.5wt. % GO content coating, the friction coefficient was reduced to near 0.1.

  2. Electrochemical combustion of indigo at ternary oxide coated titanium anodes

    Directory of Open Access Journals (Sweden)

    María I. León

    2014-12-01

    Full Text Available The film of iridium and tin dioxides doped with antimony (IrO2-SnO2–Sb2O5 deposited on a Ti substrate (mesh obtained by Pechini method was used for the formation of ·OH radicals by water discharge. Detection of ·OH radicals was followed by the use of the N,N-dimethyl-p-nitrosoaniline (RNO as a spin trap. The electrode surface morphology and composition was characterized by SEM-EDS. The ternary oxide coating was used for the electrochemical combustion of indigo textile dye as a model organic compound in chloride medium. Bulk electrolyses were then carried out at different volumetric flow rates under galvanostatic conditions using a filter-press flow cell. The galvanostatic tests using RNO confirmed that Ti/IrO2-SnO2-Sb2O5 favor the hydroxyl radical formation at current densities between 5 and 7 mA cm-2, while at current density of 10 mA cm-2 the oxygen evolution reaction occurs. The indigo was totally decolorized and mineralized via reactive oxygen species, such as (·OH, H2O2, O3 and active chlorine formed in-situ at the Ti/IrO2-SnO2-Sb2O5 surface at volumetric flow rates between 0.1-0.4 L min-1 and at fixed current density of 7 mA cm-2. The mineralization of indigo carried out at 0.2 L min-1 achieved values of 100 %, with current efficiencies of 80 % and energy consumption of 1.78 KWh m-3.

  3. Development and sintering of alumina based mixed oxide ceramic products for sensor applications in petroleum industries

    Energy Technology Data Exchange (ETDEWEB)

    Yadava, Y.P.; Muniz, L.B.; Aguiar, L.A.R.; Sanguinetti Ferreira, R.A. [Departamento de Engenharia Mecanica, Universidade Federal de Pernambuco, CEP 50741-530, Recife-PE (Brazil); Albino Aguiar, J. [Departamento de Fisica, Universidade Federal de Pernambuco, CEP 50670-901 Recife-PE (Brazil)

    2005-07-01

    In petroleum production, different types of sensors are required to monitor temperature, pressure, leakage of inflammable gases, etc. These sensors work in very hostile environmental conditions and frequently suffer from abrasion and corrosion problems. Presently perovskite oxide based ceramic materials are increasingly being used for such purposes, due to their highly inert behavior in hostile environment. In the present work, we have developed and characterized alumina based complex perovskite oxide ceramics, Ba{sub 2}AlSnO{sub 5.5}. These ceramics were prepared by solid state reaction process and produced in the form of circular discs by uniaxial pressure compaction technique. Green ceramic bodies were sintered at different sintering temperatures (1200 to 1500 deg. C) in air atmosphere. Structural and microstructural characteristics of sintered Ba{sub 2}AlMO{sub 5.5} were studied by XRD and SEM techniques. Mechanical properties were tested by Vickers microhardness tests. Ceramics sintered in the temperature range 1300 deg. C 1400 deg. C presented best results in terms of microstructural characteristics and mechanical performance. (authors)

  4. Nanoscale Phase Stability Reversal During the Nucleation and Growth of Titanium Oxide Minerals

    Science.gov (United States)

    Hummmer, D. R.; Heaney, P. J.; Kubicki, J. D.; Kent, P. R.; Post, J. E.

    2008-12-01

    Fine-grained titanium oxide minerals are important in soils, where they affect a variety of geochemical processes. They are also industrially important as catalysts, pigments, food additives, and dielectrics. Recent research has indicated an apparent reversal of thermodynamic stability between TiO2 phases at the nanoscale thought to be caused by an increased contribution of surface energy to the total free energy. Time-resolved X-ray diffraction (XRD) experiments in which titanium oxides crystallize from aqueous TiCl4 solutions confirm that anatase, a metastable phase, is always the first phase to nucleate under our range of initial conditions. Rutile peaks are observed only minutes after the first appearance of anatase, after which anatase abundance slowly decreases while rutile continues to form. Whole pattern refinement of diffraction data reveals that lattice constants of both phases increase throughout the crystallization process. In addition, transmission electron microscope (TEM) observations and kinetic modeling indicate that anatase does not undergo a solid-state transformation to the rutile structure as once thought. Instead, anatase appears to re-dissolve and then feed the growth of already nucleated rutile nanocrystals. Density functional theory (DFT) calculations were employed to model 1, 2, and 3 nm particles of both mineral phases. The total surface energies calculated from these models did yield lower values for anatase than for rutile by 8-13 kJ/mol depending on particle size, indicating that surface free energy is sufficient to account for stability reversal. However, these whole-particle surface energies were much higher than the sum of energies of each particle's constituent crystallographic surfaces. We attribute the excess energy to defects associated with the edges and corners of nanoparticles, which are not present on a 2-D periodic surface. This previously unreported edge and corner energy may play a dominant role in the stability reversal

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-03-15

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

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  7. Oxidation of Catechol using Titanium Silicate (TS-1 Catalyst: Modeling and Optimization

    Directory of Open Access Journals (Sweden)

    Sonali Sengupta

    2013-12-01

    Full Text Available The oxidation of catechol was studied in an eco-friendly process with commercial titanium silicate-1 (TS-1 catalyst and hydrogen peroxide as oxidant in absence of all mass transfer effects. The process was opti-mized by Box-Behnken design in terms of three independent process variables such as reaction tempera-ture, moles of hydrogen peroxide per mole of catechol and catalyst amount whose optimum values of the process variables were found to be 60 °C, 13.2 and 1.24 g respectively for maximum conversion of 75.8 %. The effects of different process parameters such as mole ratio of hydrogen peroxide to catechol, catalyst par-ticle size, catalyst amount, temperature and reaction time were studied. A pseudo first order kinetic model was fitted with the experimental rate data. The apparent activation energy for the reaction was found to be 11.37 kJ/mole.  © 2013 BCREC UNDIP. All rights reservedReceived: 22nd April 2013; Revised: 25th October 2013; Accepted: 1st November 2013[How to Cite: Sengupta, S., Ghosal, D., Basu, J.K. (2013. Oxidation of Catechol using Titanium Silicate (TS-1 Catalyst: Modeling and Optimization. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (2: 167-177. (doi:10.9767/bcrec.8.2.4759.167-177][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.2.4759.167-177

  8. Structural and dielectric characterization of sputtered Tantalum Titanium Oxide thin films for high temperature capacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Rouahi, A., E-mail: rouahi_ahlem@yahoo.fr [Univ. Grenoble Alpes, G2Elab, F-38000 (France); Laboratoire Matériaux Organisation et Propriétés (LMOP), Université de Tunis El Manar, 2092 Tunis (Tunisia); Challali, F. [Laboratoire des Sciences des Procédés et des Matériaux (LSPM)-CNRS-UPR3407, Université Paris13, 99 Avenue Jean-Baptiste Clément, 93430, Villetaneuse (France); Dakhlaoui, I. [Laboratoire Matériaux Organisation et Propriétés (LMOP), Université de Tunis El Manar, 2092 Tunis (Tunisia); Vallée, C. [CNRS, LTM, CEA-LETI, F-38000 Grenoble (France); Salimy, S. [Institut des Matériaux Jean Rouxel (IMN) UMR CNRS 6502, Université de Nantes, 2, rue de la Houssinière, B.P. 32229, 44322, Nantes, Cedex 3 (France); Jomni, F.; Yangui, B. [Laboratoire Matériaux Organisation et Propriétés (LMOP), Université de Tunis El Manar, 2092 Tunis (Tunisia); Besland, M.P.; Goullet, A. [Institut des Matériaux Jean Rouxel (IMN) UMR CNRS 6502, Université de Nantes, 2, rue de la Houssinière, B.P. 32229, 44322, Nantes, Cedex 3 (France); Sylvestre, A. [Univ. Grenoble Alpes, G2Elab, F-38000 (France)

    2016-05-01

    In this study, the dielectric properties of metal-oxide-metal capacitors based on Tantalum Titanium Oxide (TiTaO) thin films deposited by reactive magnetron sputtering on aluminum bottom electrode are investigated. The structure of the films was characterized by Atomic Force Microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The dielectric properties of TiTaO thin films were studied by complex impedance spectroscopy over a wide frequency range (10{sup -2} - to 10{sup 5} Hz) and temperatures in -50 °C to 325 °C range. The contributions of different phases, phases’ boundaries and conductivity effect were highlighted by Cole – Cole diagram (ε” versus ε’). Two relaxation processes have been identified in the electric modulus plot. A first relaxation process appears at low temperature with activation energy of 0.37 eV and it is related to the motion of Ti{sup 4+} (Skanavi’s model). A second relaxation process at high temperature is related to Maxwell-Wagner-Sillars relaxation with activation energy of 0.41 eV. - Highlights: • Titanium Tantalum Oxide thin films are grown on Aluminum substrate. • The existence of phases was confirmed by X-ray photoelectron spectroscopy. • Conductivity effect appears in Cole-Cole plot. • At low temperatures, a relaxation phenomenon obeys to Skanavi’s model. • Maxwell-Wagner-Sillars polarization is processed at high temperatures.

  9. Titanium dioxide-coated fluorine-doped tin oxide thin films for improving overall photoelectric property

    International Nuclear Information System (INIS)

    Li, Bao-jia; Huang, Li-jing; Ren, Nai-fei; Zhou, Ming

    2014-01-01

    Titanium (Ti) layers were deposited by direct current (DC) magnetron sputtering on commercial fluorine-doped tin oxide (FTO) glasses, followed by simultaneous oxidation and annealing treatment in a tubular furnace to prepare titanium dioxide (TiO 2 )/FTO bilayer films. Large and densely arranged grains were observed on all TiO 2 /FTO bilayer films. The presence of TiO 2 tetragonal rutile phase in the TiO 2 /FTO bilayer films was confirmed by X-ray diffraction (XRD) analysis. The results of parameter optimization indicated that the TiO 2 /FTO bilayer film, which was formed by adopting a temperature of 400 °C and an oxygen flow rate of 15 sccm, had the optimal overall photoelectric property with a figure of merit of 2.30 × 10 −2 Ω −1 , higher than 1.78 × 10 −2 Ω −1 for the FTO single-layer film. After coating a 500 nm-thick AZO layer by DC magnetron sputtering on this TiO 2 /FTO bilayer film, the figure of merit of the trilayer film achieved to a higher figure of merit of 3.12 × 10 −2 Ω −1 , indicating further improvement of the overall photoelectric property. This work may provide a scientific basis and reference for improving overall photoelectric property of transparent conducting oxide (TCO) films.

  10. Titanium dioxide-coated fluorine-doped tin oxide thin films for improving overall photoelectric property

    Energy Technology Data Exchange (ETDEWEB)

    Li, Bao-jia, E-mail: bjia_li@126.com [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang 212013 (China); Huang, Li-jing [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang 212013 (China); Ren, Nai-fei [Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang 212013 (China); School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); Zhou, Ming [The State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China)

    2014-01-30

    Titanium (Ti) layers were deposited by direct current (DC) magnetron sputtering on commercial fluorine-doped tin oxide (FTO) glasses, followed by simultaneous oxidation and annealing treatment in a tubular furnace to prepare titanium dioxide (TiO{sub 2})/FTO bilayer films. Large and densely arranged grains were observed on all TiO{sub 2}/FTO bilayer films. The presence of TiO{sub 2} tetragonal rutile phase in the TiO{sub 2}/FTO bilayer films was confirmed by X-ray diffraction (XRD) analysis. The results of parameter optimization indicated that the TiO{sub 2}/FTO bilayer film, which was formed by adopting a temperature of 400 °C and an oxygen flow rate of 15 sccm, had the optimal overall photoelectric property with a figure of merit of 2.30 × 10{sup −2} Ω{sup −1}, higher than 1.78 × 10{sup −2} Ω{sup −1} for the FTO single-layer film. After coating a 500 nm-thick AZO layer by DC magnetron sputtering on this TiO{sub 2}/FTO bilayer film, the figure of merit of the trilayer film achieved to a higher figure of merit of 3.12 × 10{sup −2} Ω{sup −1}, indicating further improvement of the overall photoelectric property. This work may provide a scientific basis and reference for improving overall photoelectric property of transparent conducting oxide (TCO) films.

  11. Electrophoretic deposition of calcium silicate-reduced graphene oxide composites on titanium substrate

    DEFF Research Database (Denmark)

    Mehrali, Mehdi; Akhiani, Amir Reza; Talebian, Sepehr

    2016-01-01

    Calcium silicate (CS)/graphene coatings have been used to improve the biological and mechanical fixation of metallic prosthesis. Among the extraordinary features of graphene is its very high mechanical strength, which makes it an attractive nanoreinforcement material for composites. Calcium...... silicate-reduced graphene oxide (CS-rGO) composites were synthesized, using an in situ hydrothermal method. CS nanowires were uniformly decorated on the rGO, with an appropriate interfacial bonding. The CS-rGO composites behaved like hybrid composites when deposited on a titanium substrate by cathodic...

  12. Photocatalytic action of cerium molybdate and iron-titanium oxide hollow nanospheres on Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Kartsonakis, I. A., E-mail: ikartsonakis@ims.demokritos.gr; Kontogiani, P.; Pappas, G. S.; Kordas, G. [NCSR ' DEMOKRITOS' , Sol-Gel Laboratory, Institute of Advanced Materials, Physicochemical Processes, Nanotechnology and Microsystems (Greece)

    2013-06-15

    This study is focused on the production of hollow nanospheres that reveal antibacterial action. Cerium molybdate and iron-titanium oxide hollow nanospheres with a diameter of 175 {+-} 15 and 221 {+-} 10 nm, respectively, were synthesized using emulsion polymerization and the sol-gel process. Their morphology characterization was accomplished using scanning electron microscopy. Their antibacterial action was examined on pure culture of Escherichia coli considering the loss of their viability. Both hollow nanospheres presented photocatalytic action after illumination with blue-black light, but those of cerium molybdate also demonstrated photocatalytic action in the dark. Therefore, the produced nanospheres can be used for antibacterial applications.

  13. Photocatalytic action of cerium molybdate and iron-titanium oxide hollow nanospheres on Escherichia coli

    International Nuclear Information System (INIS)

    Kartsonakis, I. A.; Kontogiani, P.; Pappas, G. S.; Kordas, G.

    2013-01-01

    This study is focused on the production of hollow nanospheres that reveal antibacterial action. Cerium molybdate and iron-titanium oxide hollow nanospheres with a diameter of 175 ± 15 and 221 ± 10 nm, respectively, were synthesized using emulsion polymerization and the sol–gel process. Their morphology characterization was accomplished using scanning electron microscopy. Their antibacterial action was examined on pure culture of Escherichia coli considering the loss of their viability. Both hollow nanospheres presented photocatalytic action after illumination with blue–black light, but those of cerium molybdate also demonstrated photocatalytic action in the dark. Therefore, the produced nanospheres can be used for antibacterial applications.

  14. Non-oxidic nanoscale composites: single-crystalline titanium carbide nanocubes in hierarchical porous carbon monoliths.

    Science.gov (United States)

    Sonnenburg, Kirstin; Smarsly, Bernd M; Brezesinski, Torsten

    2009-05-07

    We report the preparation of nanoscale carbon-titanium carbide composites with carbide contents of up to 80 wt%. The synthesis yields single-crystalline TiC nanocubes 20-30 nm in diameter embedded in a hierarchical porous carbon matrix. These composites were generated in the form of cylindrical monoliths but can be produced in various shapes using modern sol-gel and nanocasting methods in conjunction with carbothermal reduction. The monolithic material is characterized by a combination of microscopy, diffraction and physisorption. Overall, the results presented in this work represent a concrete design template for the synthesis of non-oxidic nanoscale composites with high surface areas.

  15. Experimental Investigations on the Influence of Adhesive Oxides on the Metal-Ceramic Bond

    Directory of Open Access Journals (Sweden)

    Susanne Enghardt

    2015-01-01

    Full Text Available The objective of this study was to test the influence of selected base metals, which act as oxide formers, on the metal-ceramic bond of dental veneer systems. Using ion implantation techniques, ions of Al, In and Cu were introduced into near-surface layers of a noble metal alloy containing no base metals. A noble metal alloy with base metals added for oxide formation was used as a reference. Both alloys were coated with a low-temperature fusing dental ceramic. Specimens without ion implantation or with Al2O3 air abrasion were used as controls. The test procedures comprised the Schwickerath shear bond strength test (ISO 9693-1, profile height (surface roughness measurements (ISO 4287; ISO 4288; ISO 25178, scanning electron microscopy (SEM imaging, auger electron spectroscopy (AES and energy dispersive X-ray analysis (EDX. Ion implantation resulted in no increase in bond strength. The highest shear bond strengths were achieved after oxidation in air and air abrasion with Al2O3 (41.5 MPa and 47.8 MPa respectively. There was a positive correlation between shear bond strength and profile height. After air abrasion, a pronounced structuring of the surface occurred compared to ion implantation. The established concentration shifts in alloy and ceramic could be reproduced. However, their positive effects on shear bond strength were not confirmed. The mechanical bond appears to be of greater importance for metal-ceramic bonding.

  16. Oxygen transport by oxygen potential gradient in dense ceramic oxide membranes

    Energy Technology Data Exchange (ETDEWEB)

    Maiya, P.S.; Balachandran, U.; Dusek, J.T.; Mieville, R.L. [Argonne National Lab., IL (United States). Energy Technology Div.; Kleefisch, M.S.; Udovich, C.A. [Amoco Exploration/Production, Naperville, IL (United States)

    1996-05-01

    Numerous studies have been conducted in recent years on the partial oxidation of methane to synthesis gas (syngas: CO + H{sub 2}) with air as the oxidant. In partial oxidation, a mixed-oxide ceramic membrane selectively transports oxygen from the air; this transport is driven by the oxygen potential gradient. Of the several ceramic materials the authors have tested, a mixed oxide based on the Sr-Fe-Co-O system has been found to be very attractive. Extensive oxygen permeability data have been obtained for this material in methane conversion experiments carried out in a reactor. The data have been analyzed by a transport equation based on the phenomenological theory of diffusion under oxygen potential gradients. Thermodynamic calculations were used to estimate the driving force for the transport of oxygen ions. The results show that the transport equation deduced from the literature describes the permeability data reasonably well and can be used to determine the diffusion coefficients and the associated activation energy of oxygen ions in the ceramic membrane material.

  17. Zirconium oxide deposits (ZrO2) and titanium oxide (TiO2) on 304l stainless steel

    International Nuclear Information System (INIS)

    Davila N, M. L.

    2015-01-01

    This research project aims to carry out the surface and electrochemical characterization to obtain the optimum conditions of the hydrothermal deposits of zirconium oxide ZrO 2 (baddeleyite) and titanium oxide TiO 2 (anatase and rutile phases) on 304l stainless steel, simulating an inhibiting protective layer. 304l steel specimens were cut, pre-oxidized in water at a temperature of 288 degrees Celsius and 8 MPa, similar to those of a typical BWR conditions. From the titanium oxide anatase crystalline phase, the rutile phase was obtained by a heat treatment at 1000 degrees Celsius. The Sigma-Aldrich pre-oxidized powders and steel 304l were characterized using techniques of X-ray diffraction, scanning electron microscopy, X-ray dispersive energy, chemical mapping and Raman spectrometry. The pre-oxidized steel has two oxide layers, an inner layer with nano metric crystals and another outer of larger crystals to 1μm, with the formation of hematite and magnetite, this predominating. The surface that contacted the sample holder has larger crystals. Hydrothermal deposits were carry out from suspensions of 10, 100 and 1000 ppm, of the crystal phases of anatase, rutile and baddeleyite, on the pre-oxidized steel at a temperature of 150 degrees Celsius for 2 and 7 days, samples were analyzed by X-ray diffraction, scanning electron microscopy, X-ray dispersive energy, Raman spectrometry and Tafel polarization. The suspension to 1000 ppm for 7 days coated surface most; the baddeleyite deposit is noticed more homogeneous than anatase and rutile. The deposit is favored when hematite and magnetite crystals are larger. The chemical mapping on deposits show that even after being immersed in water to 288 degrees Celsius during 30 days, the deposits are still present although a loss is observed. A reference electrode was assembled to conduct electrochemical tests of Tafel able to withstand a temperature of 288 degrees Celsius and pressure of 8 MPa. The baddeleyite deposit presented

  18. Generation of an electromotive force by hydrogen-to-water oxidation with Pt-coated oxidized titanium foils

    Energy Technology Data Exchange (ETDEWEB)

    Schierbaum, Klaus; El Achhab, Mhamed [Department of Materials Science, Institute for Experimental Condensed Matter Physics, Heinrich-Heine University, 40225 Duesseldorf, Universitaetsstrasse 1 (Germany)

    2011-12-15

    We show that chemically induced current densities up to 20 mA cm{sup -2} and an electromotive force (EMF) up to 465 mV are generated during the hydrogen-to-water-oxidation over Pt/TiO{sub 2}/Ti devices. We prepare the samples by plasma electrolytic oxidation (PEO) of titanium foils and deposition of Pt contact paste. This process yields porous structures and, depending on the anodization voltage, Schottky diode-type current-voltage curves of various ideality parameters. Our experiments demonstrate that Pt coated anodized titanium can also be utilized as hydrogen sensor; the system offers a number of advantages such as a wide temperature range of operation from -40 to 80 C, quick response and decay times of signals, and good electrical stability. Idealized sketch of the Pt coated anodized Ti foil and application as hydrogen sensor and electric generator. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Effect of yttria addition on the stability of porous chromium oxide ceramics in supercritical water

    International Nuclear Information System (INIS)

    Dong Ziqiang; Chen Weixing; Zheng Wenyue; Guzonas, Dave

    2013-01-01

    Porous chromium oxide (Cr 2 O 3 ) ceramics were prepared by oxidizing highly porous chromium carbides that were obtained by a reactive sintering method, and were evaluated at temperatures ranging from 375 °C to 625 °C in supercritical water (SCW) environments with a fixed pressure of 25–30 MPa. Reactive element yttrium was introduced to the porous oxide ceramic by adding various amounts of yttria of 5, 10 and 20 wt.%, respectively, prior to reactive sintering. The exposure in SCW shows that the porous chromium oxide is quite stable in SCW at 375 °C. However, the stability decreased with increasing temperature. It is well known that chromium oxide can be oxidized to soluble chromium (VI) species in SCW when oxygen is present. Adding yttria increases the stability of chromium oxide in SCW environments. However, adding yttria higher than 5 wt.% increased the weight loss of porous chromium oxide samples because of the direct dissociation of Y 2 O 3 in SCW.

  20. In-situ synthesis and performance of titanium oxide/poly(methyl methacrylate) nanocomposites.

    Science.gov (United States)

    Bandugula, Uttam C; Clayton, L M; Harmon, J P; Kumar, Ashok

    2005-05-01

    Polymer nanocomposites have elicited extensive research efforts due to their potential to exhibit spectacular properties. They have immense potential and are befitting materials to serve as an ideal and futuristic alternative for varied applications. Poly(methyl methacrylate) (PMMA) and titanium oxide (TiO2) nanocomposites used in this study were fabricated by an in-situ free radical polymerization process. Three point bend tests were conducted with a modified universal microtribometer to evaluate fracture toughness. The results indicated that the stress intensity values increase as the concentration of titanium oxide increases up to 1 vol% and subsequently decrease at higher concentrations. Scanning electron microscopy (SEM) images of fracture surfaces afforded clues as to the possible deformation mechanism. Ultraviolet-visible spectroscopy (UV-vis) evaluated the degree of transparency of the nanocomposites. It was observed that samples became opaque as the concentration was increased beyond 0.01% volume fraction. X-ray diffraction characterized the TiO2 crystalline phase and Scherrer's equation was used to calculate the crystallite size. Among the concentrations considered the 3% volume fraction sample had the largest crystallite size. Finally, microhardness measurements further characterized the mechanical properties of the composites.

  1. Cobalt Fischer-Tropsch catalysts: influence of cobalt dispersion and titanium oxides promotion

    Energy Technology Data Exchange (ETDEWEB)

    Azib, H

    1996-04-10

    The aim of this work is to study the effect of Sol-Gel preparation parameters which occur in silica supported cobalt catalysts synthesis. These catalysts are particularly used for the waxes production in natural gas processing. The solids have been characterized by several techniques: transmission electron microscopy (TEM), X-ray absorption near edge spectroscopy (XANES), programmed temperature reduction (TPR), infrared spectroscopy (IR), ultraviolet spectroscopy (UV), Magnetism, thermodesorption of H{sub 2} (TPD). The results indicate that the control of the cobalt dispersion and oxide phases nature is possible by modifying Sol-Gel parameters. The catalytic tests in Fischer-Tropsch synthesis were conducted on a pilot unit under pressure (20 atm) and suggested that turnover rates were independent of Co crystallite size, Co phases in the solids (Co deg., cobalt silicate) and titanium oxide promotion. On the other methane, the C{sub 3}{sup +} hydrocarbon selectivity is increased with increasing crystallite size. Inversely, the methane production is favoured by very small crystallites, cobalt silicate increase and titanium addition. However, the latter, used as a cobalt promoter, has a benefic effect on the active phase stability during the synthesis. (author). 149 refs., 102 figs., 71 tabs.

  2. ATOMIC LAYER DEPOSITION OF TITANIUM OXIDE THIN FILMS ONNANOPOROUS ALUMINA TEMPLATES FOR MEDICAL APPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Brigmon, R.

    2009-05-05

    Nanostructured materials may play a significant role in controlled release of pharmacologic agents for treatment of cancer. Many nanoporous polymer materials are inadequate for use in drug delivery. Nanoporous alumina provides several advantages over other materials for use in controlled drug delivery and other medical applications. Atomic layer deposition was used to coat all the surfaces of the nanoporous alumina membrane in order to reduce the pore size in a controlled manner. Both the 20 nm and 100 nm titanium oxide-coated nanoporous alumina membranes did not exhibit statistically lower viability compared to the uncoated nanoporous alumina membrane control materials. In addition, 20 nm pore size titanium oxide-coated nanoporous alumina membranes exposed to ultraviolet light demonstrated activity against Escherichia coli and Staphylococcus aureus bacteria. Nanostructured materials prepared using atomic layer deposition may be useful for delivering a pharmacologic agent at a precise rate to a specific location in the body. These materials may serve as the basis for 'smart' drug delivery devices, orthopedic implants, or self-sterilizing medical devices.

  3. Microstructure of titanium oxide films synthesized by ion beam dynamic mixing

    International Nuclear Information System (INIS)

    Makino, Y.; Setsuhara, Y.; Miyake, S.

    1994-01-01

    The microstructure of titanium oxide films synthesized by the ion beam dynamic mixing (IBDM) method is investigated by glancing angle X-ray diffraction and multi-reflectance FT-IR methods. Titanium oxide films are identified as rutile phases having different degrees of (110) orientation. The IBDM rutile phase with a standard crystalline state is produced by controlling the ratio of the intensities between the (110) and (101) peaks of the rutile, I(110)/I(101), so as to approach the ratio to the value (=2.0) of ASTM standard rutile. The crystallite size of the rutile phase increases with increasing ratio of intensities of the two XRD peaks, I(110)/I(101). The increase of the crystallite size is suggested to be attributed to the increase of oxygen ion energy per Ti atom. From the dependence of the IR absorption near 500 cm -1 upon I(110)/I(101), it is indicated that the Ti-O bond strength is delicately affected by the degree of (110) orientation of the IBDM rultile phase. ((orig.))

  4. Polymer-Derived Ceramics as Innovative Oxidation Barrier Coatings for Mo-Si-B Alloys

    Science.gov (United States)

    Hasemann, Georg; Baumann, Torben; Dieck, Sebastian; Rannabauer, Stefan; Krüger, Manja

    2015-04-01

    A preceramic polymer precursor, perhydropolysilazane, is used to investigate its function as a new type of oxidation barrier coating on Mo-Si-B alloys. After dip-coating and pyrolysis at 1073 K (800 °C), dense and well-adhering SiON ceramic coatings could be achieved, which were investigated by SEM and cyclic oxidation tests at 1073 K and 1373 K (800 °C and 1100 °C). The coating is promising in reducing the mass loss during the initial stage of oxidation exposure at 1373 K (1100 °C) significantly.

  5. Oxidation Behavior of Titanium Carbonitride Coating Deposited by Atmospheric Plasma Spray Synthesis

    Science.gov (United States)

    Zhu, Lin; He, Jining; Yan, Dianran; Liao, Hanlin; Zhang, Nannan

    2017-10-01

    As a high-hardness and anti-frictional material, titanium carbonitride (TiCN) thick coatings or thin films are increasingly being used in many industrial fields. In the present study, TiCN coatings were obtained by atmospheric plasma spray synthesis or reactive plasma spray. In order to promote the reaction between the Ti particles and reactive gases, a home-made gas tunnel was mounted on a conventional plasma gun to perform the spray process. The oxidation behavior of the TiCN coatings under different temperatures in static air was carefully investigated. As a result, when the temperature was over 700 °C, the coatings suffered from serious oxidation, and finally they were entirely oxidized to the TiO2 phase at 1100 °C. The principal oxidation mechanism was clarified, indicating that the oxygen can permeate into the defects and react with TiCN at high temperatures. In addition, concerning the use of a TiCN coating in high-temperature conditions, the microhardness of the oxidized coatings at different treatment temperatures was also evaluated.

  6. Improvement of biological properties of titanium by anodic oxidation and ultraviolet irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Baoe [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China); Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Li, Ying [Stomatological Hospital, Tianjin Medical University, Tianjin 300070 (China); Li, Jun [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China); Fu, Xiaolong; Li, Changyi [Stomatological Hospital, Tianjin Medical University, Tianjin 300070 (China); Wang, Hongshui [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China); Liu, Shimin [Business School, Tianjin University of Commerce, Tianjin 300134 (China); Guo, Litong [China University of Mining and Technology, Xuzhou 221116 (China); Xin, Shigang [Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Liang, Chunyong, E-mail: liangchunyong@126.com [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China); Li, Haipeng, E-mail: lhpcx@163.com [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China)

    2014-07-01

    Anodic oxidation was applied to produce a homogeneous and uniform array of nanotubes of about 70 nm on the titanium (Ti) surface, and then, the nanotubes were irradiated by ultraviolet. The bioactivity of the Ti surface was evaluated by simulated body fluid soaking test. The biocompatibility was investigated by in vitro cell culture test. The results showed that bone-like apatite was formed on the anodic oxidized and UV irradiated Ti surface, but not on the as-polished Ti surface after immersion in simulated body fluid for two weeks. Cells cultured on the anodic oxidized Ti surface showed enhanced cell adhesion and proliferation, also presented an up-regulated gene expression of osteogenic markers OPG, compared to those cultured on the as-polished Ti surface. After UV irradiation, the cell behaviors were further improved, indicating better biocompatibility of Ti surface. Based on these results, it can be concluded that anodic oxidation improved the biological properties (bioactivity and biocompatibility) of Ti surface, while UV irradiation improved the biocompatibility to a better extent. The improved biological properties were attributed to the nanostructures as well as the enhanced hydrophilicity. Therefore, anodic oxidation combined with UV irradiation can be used to enhance the biological properties of Ti-based implants.

  7. Nano-oxides to improve the surface properties of ceramic tiles

    International Nuclear Information System (INIS)

    Rambaldi, E.; Tucci, A.; Esposito, L.; Naldi, D.; Timellini, G.

    2010-01-01

    The aim of the present work is to realise ceramic tiles with superior surface mechanical characteristics and chemical resistance, by the addition of nano-oxides, such as zirconia and alumina, since such advanced ceramics oxides are well known for their excellent mechanical properties and good resistance to chemical etching. In order to avoid any dangerousness, the nanoparticles were used in form of aqueous suspension and they were sprayed, by airbrush, directly onto the dried ceramic support, before firing. To observe the distribution of the nanoparticles and to optimise the surface treatment, SEM-EDS analyses were carried out on the fired samples. XRD analysis was conducted to assess the phases evolution of the different materials during the firing step. The surface mechanical characteristics of the samples have been evaluated by Vickers hardness and scratch test. In addition, also chemical resistance tests were performed. Microstructural observations allowed to understand how alumina and zirconia nanoparticles acted to improve the surface performances of the modified ceramic tiles. (Author) 20 refs.

  8. Corrosion behaviour of porous chromium carbide/oxide based ceramics in supercritical water

    International Nuclear Information System (INIS)

    Dong, Z.; Xin, T.; Chen, W.; Zheng, W.; Guzonas, D.

    2011-01-01

    Porous chromium carbide with a high density of open pores was fabricated by a reactive sintering method. Chromium oxide ceramics were obtained by re-oxidizing the porous chromium carbides formed. Some samples were added with yttria at 5 wt. %, prior to reactive sintering to form porous structures. Corrosion tests in SCW were performed at temperatures ranging from 375 o C to 625 o C with a fixed pressure at around 25∼30 MPa. The results show that chromium carbide is stable in SCW environments at temperatures up to 425 o C, above which disintegration of carbides through oxidation occurs. Porous chromium oxide samples show better corrosion resistance than porous chromium carbide, but disintegrate in SCW at around 625 o C. Among all the samples tested, chromium oxide ceramics with added yttria exhibited much better corrosion resistance compared with the pure chromium carbide/oxides. No evidence of weight change or disintegration of porous chromium oxides with 5 wt % added yttria was observed after exposure at 625 o C in SCW for 600 hours. (author)

  9. Oxidation and corrosion of silicon-based ceramics and composites

    International Nuclear Information System (INIS)

    Jacobson, N.S.; Fox, D.S.; Smialek, J.L.

    1997-01-01

    Silica scales exhibit slow growth rates and a low activation energy. Thus silica-protected materials are attractive high temperature structural materials for their potentially excellent oxidation resistance and well-documented high temperature strength. This review focuses on silicon carbide, silicon nitride, and composites of these materials. It is divided into four parts: (i) Fundamental oxidation mechanisms, (ii) Special properties of silica scales, (iii) Protective coatings, and (iv) Internal oxidation behavior of composites. While the fundamental oxidation mechanism of SiC is understood, there are still many questions regarding the oxidation mechanism of Si 3 N 4 . Silica scales exhibit many unique properties as compared to chromia and alumina. These include slower growth rates, SiO(g) formation, sensitivity to water vapor and impurities, and dissolution by basic molten salts. Protective coatings can limit the deleterious effects. The fourth area-internal oxidation of fibers and fiber coatings in composites-has limited the application of these novel materials. Strategies for understanding and limiting this internal oxidation are discussed. (orig.)

  10. Relative SHG measurements of metal thin films: Gold, silver, aluminum, cobalt, chromium, germanium, nickel, antimony, titanium, titanium nitride, tungsten, zinc, silicon and indium tin oxide

    Directory of Open Access Journals (Sweden)

    Franklin Che

    Full Text Available We have experimentally measured the surface second-harmonic generation (SHG of sputtered gold, silver, aluminum, zinc, tungsten, copper, titanium, cobalt, nickel, chromium, germanium, antimony, titanium nitride, silicon and indium tin oxide thin films. The second-harmonic response was measured in reflection using a 150 fs p-polarized laser pulse at 1561 nm. We present a clear comparison of the SHG intensity of these films relative to each other. Our measured relative intensities compare favorably with the relative intensities of metals with published data. We also report for the first time to our knowledge the surface SHG intensity of tungsten and antimony relative to that of well known metallic thin films such as gold and silver. Keywords: Surface second-harmonic generation, Nonlinear optics, Metal thin films

  11. ELECTROKINETIC PROPERTIES, IN VITRO DISSOLUTION, AND PROSPECTIVE HEMOAND BIOCOMPATIBILITY OF TITANIUM OXIDE AND OXYNITRIDE FILMS FOR CARDIOVASCULAR STENTS

    Directory of Open Access Journals (Sweden)

    I. A. Khlusov

    2015-01-01

    Full Text Available A state of titanium oxide and oxynitride coatings on L316 steel has been studied before and after their contact with model biological fluids. Electrokinetic investigation in 1 mmol potassium chloride showed significant (more than 10 times fall of magnitude of electrostatic potential of thin (200–300 nm titanium films at pH changing in the range of 5–9 units during 2 h. Nevertheless, zeta-potential of all samples had negative charge under pH > 6.5. Long-term (5 weeks contact of samples with simulated body fluid (SBF promoted steel corrosion and titanium oxide and oxynitride films dissolution. On the other hand, sodium and chloride ions precipitation and sodium chloride crystals formation occurred on the samples. Of positive fact is an absence of calcification of tested artificial surfaces in conditions of long-term being in SBF solution. It is supposed decreasing hazard of fast thrombosis and loss of materials functional properties. According to in vitro experiment conducted, prospective biocompatibility of materials tested before and after their contact with SBF lines up following manner: Ti–O–N (1/3 > Ti–O–N (1/1, TiO2 > Steel. It may be explained by: 1 the corrosion-preventive properties of thin titanium oxide and oxynitride films;2 a store of surface negative charge for Ti–O–N (1/3 film; 3 minor augmentation of mass and thickness of titanium films connected with speed of mineralization processes on the interface of solution/solid body. At the same time, initial (before SBF contact differences of samples wettability became equal. Modifying effect of model biological fluids on physicochemical characteristics of materials tested (roughness enhancement, a reduction or reversion of surface negative potential, sharp augmentation of surface hydrofilicity should took into account under titanium oxide and oxynitride films formation and a forecast of their optimal biological properties as the materials for cardiovascular stents.

  12. Synthesis and characterization of ceramic pigments based on oxides of chromium and iron, on TiO{sub 2}; Sintese e caracterizacao de pigmentos ceramicos a base de oxidos de cromo e de ferro, depositados sobre TiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Silva, E.M. da; Galvao, S.B.; Paskocimas, C.A., E-mail: everlania_siva@yahoo.com.br [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2011-07-01

    This work used oxides of chromium and iron, as precursors of the synthesis of ceramic pigments. The synthesis is based on the dissolution of citric acid as a complexing agent, addition of metal oxides, such as ion chromophores; polymerization with ethylene glycol and doping with titanium oxide. Passing through pre-calcination, breakdown, calcination at different temperatures (900 and 1100 ° C), resulting in pigments: green for pigment chrome deposited on TiO{sub 2} and orange for iron on TiO{sub 2}. Noticing an increase in the opacity with increasing temperature. The thermal analysis (TG and DTA), evaluated their thermal behavior, the XRD revealed the formation of crystalline phases as Iron Titanate and Chrome Titanate; SEM showed the formation of hexagonal particles for both oxides. Thus, the synthesized oxides were within the requirements for application as ceramic pigments. (author)

  13. Application of cylinder symmetry to iron and titanium oxidation by oxygen or hydrogen-water vapour mixes

    International Nuclear Information System (INIS)

    Raynaud, Pierre

    1980-01-01

    This research thesis addresses the study of the oxidation reaction in the case of corrosion of iron by oxygen, hydrogen sulphide or hydrogen-water vapour mixes, and in the case of oxidation of titanium and of titanium nitride by hydrogen-water vapour mixes. It first addresses the corrosion of iron by oxygen with an experiment performed in cylinder symmetry: description of operational conditions, discussion of kinetic curves, development of a law of generation of multiple layers in cylinder symmetry, analytical exploitation of experimental results. The second part addresses the oxidation of iron by hydrogen-water vapour mixes: experimental conditions, influence of temperature on kinetics, micrographic study (oxide morphology, coating morphology, interpretation of differences with the case of plane symmetry), discussion of the influence of cylinder symmetry on oxidation kinetics. The third part addresses the oxidation of titanium by hydrogen-water vapour mixes: global kinetic evolution, reaction products and micrographic examination, morphology and texture studies, discussion of the oxidation mechanism and of cylinder symmetry [fr

  14. Development of iron oxide and titania treated fly ash based ceramic and its bioactivity

    Energy Technology Data Exchange (ETDEWEB)

    Sultana, Parveen [Physics Department, Jadavpur University, Kolkata-700 032 (India); Das, Sukhen, E-mail: das_sukhen@yahoo.com [Physics Department, Jadavpur University, Kolkata-700 032 (India); Bhattacharya, Alakananda [Physics Department, West Bengal State University, Barasat (India); Basu, Ruma [Physics Department, Jogamaya Devi College, Kolkata-700026 (India); Nandy, Papiya [Centre for Interdisciplinary Research and Education, Kolkata-700 068 (India)

    2012-08-01

    The increasing accumulation of fly ash from thermal power plants poses a major problem to the environment. The present work reflects the novel utilization of this profusely available industrial waste in the form of an antibacterial hard ceramic material by treating fly ash with ferric oxide (Fe{sub 2}O{sub 3}) and titania (TiO{sub 2}) during sintering process at 1600 Degree-Sign C. The developed material shows more than 90% bacterial reduction against both Gram-positive and Gram-negative bacteria. The mechanism of their antibacterial action was studied by transmission electron microscopy (TEM) image analysis of the bacterial cross-section. The developed ceramic material acquires hardness due to the enhancement of the natural mullite content in the matrix. The mullite content and the crystallinity of mullite have shown their increasing trend with increasing concentration of the metal oxide during sintering process. A maximum of {approx} 37% increase in mullite was obtained for 7% w/w Fe{sub 2}O{sub 3} and TiO{sub 2}. Metal oxide lowered the activation energy of the reaction and enhanced the reaction rate of alumina (Al{sub 2}O{sub 3})-silica (SiO{sub 2}) to form mullite which increases the hardness. The study highlights novel utilization of fly ash as a hard ceramic antibacterial product (bioceramics) for both structural and hygiene applications in an eco-friendly way. - Highlights: Black-Right-Pointing-Pointer A novel antibacterial hard ceramic material by treating fly ash with metal oxide. Black-Right-Pointing-Pointer The material shows excellent antibacterial activity (> 90%) against pathogenic bacteria. Black-Right-Pointing-Pointer Mechanism of antibacterial action by TEM analysis. Black-Right-Pointing-Pointer Enhancement of the concentration of 'natural mullite content' in the material. Black-Right-Pointing-Pointer Hardness induced by enhanced mullite content is an added advantage for prolonged product life.

  15. A New Approach to Joining Dissimilar Ceramic Oxides for Chemical Sensors

    International Nuclear Information System (INIS)

    Zhuiykov, Serge

    2009-01-01

    Conventional joining of dissimilar oxides for sensing electrodes (SE) of chemical sensors has been pivotal to the development of various sensors and is vital to their further development. However, it is shown that the uncertainty (of a fundamental nature) in the properties of dissimilar oxides in SE causes the determination of their sensing characteristics to be ambiguous. Characteristics are different for such controlled parameters as pyrolysis temperature, crystal structure, particle's morphology and size, chemical and phase composition, the coefficient of thermal expansion (CTE), surface architecture, the bulk and surface stoichiometry and type and conductivity of additives. Here, we provide an alternative approach for joining dissimilar metal-oxides for chemical sensors SE. The approach relies on the development of at least one transient liquid oxide phase on the ceramic-SE interface. These results constitute key points relevant to selection oxides for joining, sintering temperatures and heating/cooling temperature rates.

  16. Germination and early plant development of ten plant species exposed to titanium dioxide and cerium oxide nanoparticles

    Science.gov (United States)

    Ten agronomic plant species were exposed to different concentrations of nano titanium dioxide (nTiO2) or nano cerium oxide (nCeO2) (0, 250, 500 and 1000 mg/L) to examine potential effects on germination and early seedling development. We modified a standard test protocol develop...

  17. Tuning the Electronic Structure of Titanium Oxide Support to Enhance the Electrochemical Activity of Platinum Nanoparticles

    KAUST Repository

    Shi, Feifei

    2013-09-11

    Two times higher activity and three times higher stability in methanol oxidation reaction, a 0.12 V negative shift of the CO oxidation peak potential, and a 0.07 V positive shift of the oxygen reaction potential compared to Pt nanoparticles on pristine TiO2 support were achieved by tuning the electronic structure of the titanium oxide support of Pt nanoparticle catalysts. This was accomplished by adding oxygen vacancies or doping with fluorine. Experimental trends are interpreted in the context of an electronic structure model, showing an improvement in electrochemical activity when the Fermi level of the support material in Pt/TiOx systems is close to the Pt Fermi level and the redox potential of the reaction. The present approach provides guidance for the selection of the support material of Pt/TiOx systems and may be applied to other metal-oxide support materials, thus having direct implications in the design and optimization of fuel cell catalyst supports. © 2013 American Chemical Society.

  18. Reduction of titanium dioxide and other metal oxides by electro-deoxidation

    International Nuclear Information System (INIS)

    Fray, Derek J.

    2003-01-01

    Titanium dioxide and other reactive metal compounds are reduced by more reactive metals to form pure metals. These, are expensive and time consuming processes which makes these metals very expensive. Many of these metals and alloys have excellent properties, high strength, low density and very good corrosion resistance, but their use is restricted by its high cost. Electro-deoxidation is a very simple technique where an oxide is made cathodic in a fused salt of an alkaline earth chloride. By applying a voltage, below the decomposition potential of the salt, it has been found that the cathodic reaction is the ionization of oxygen from the oxide to leave a pure metal, rather than the reduction of the ion alkaline earth ion element. Laboratory experiments have shown that this approach can be applied to the reduction of a large number of metal oxides. Another important observation is that when a mixture of oxides is used as the cathode, the product is an alloy of uniform composition. This is a considerable advantage for many alloys that are difficult to prepare using conventional technology. (Original)

  19. Titanium-Niobium Oxides as Non-Noble Metal Cathodes for Polymer Electrolyte Fuel Cells

    Directory of Open Access Journals (Sweden)

    Akimitsu Ishihara

    2015-07-01

    Full Text Available In order to develop noble-metal- and carbon-free cathodes, titanium-niobium oxides were prepared as active materials for oxide-based cathodes and the factors affecting the oxygen reduction reaction (ORR activity were evaluated. The high concentration sol-gel method was employed to prepare the precursor. Heat treatment in Ar containing 4% H2 at 700–900 °C was effective for conferring ORR activity to the oxide. Notably, the onset potential for the ORR of the catalyst prepared at 700 °C was approximately 1.0 V vs. RHE, resulting in high quality active sites for the ORR. X-ray (diffraction and photoelectron spectroscopic analyses and ionization potential measurements suggested that localized electronic energy levels were produced via heat treatment under reductive atmosphere. Adsorption of oxygen molecules on the oxide may be governed by the localized electronic energy levels produced by the valence changes induced by substitutional metal ions and/or oxygen vacancies.

  20. Photocatalytic selective oxidation of phenol in suspensions of titanium dioxide with exposed {0 0 1} facets

    International Nuclear Information System (INIS)

    Ye, Hengpeng; Lu, Shaoming

    2013-01-01

    Anatase TiO 2 nanocrystals with exposed {0 0 1} facets were tailored by hydrothermal treatment of Ti(OC 4 H 9 ) 4 –HF–H 2 O mixed solution. The photocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen adsorption–desorption isotherms and X-ray photoelectron spectroscopy (XPS). The effect of structure of the photocatalyst on the photocatalytic selective oxidation of phenol under UV irradiation was studied. The experiment results showed that (1) the percentage of the exposed {0 0 1} facets of the nanocrystal increases with increasing the nominal atomic ratio of fluorine to titanium (R F ), (2) catechol and hydroquinone are main intermediates detected during photocatalytic oxidation of phenol, and (3) both photocatalytic oxidation of phenol and selectivity (yield) of catechol are positively correlated with the percentage of exposed {0 0 1} facets of the high-energy TiO 2 nanocrystals. The enhanced conversion of phenol and selectivity (yield) of catechol were ascribed to the synergistic effects of the exposed high-energy {0 0 1} facets and surface fluorination. This study may provide new insight into the selective oxidation of organics.

  1. Biocompatibility study of lithium disilicate and zirconium oxide ceramics for esthetic dental abutments

    Science.gov (United States)

    2016-01-01

    Purpose The increasing demand for esthetically pleasing results has contributed to the use of ceramics for dental implant abutments. The aim of this study was to compare the biological response of epithelial tissue cultivated on lithium disilicate (LS2) and zirconium oxide (ZrO2) ceramics. Understanding the relevant physicochemical and mechanical properties of these ceramics will help identify the optimal material for facilitating gingival wound closure. Methods Both biomaterials were prepared with 2 different surface treatments: raw and polished. Their physicochemical characteristics were analyzed by contact angle measurements, scanning white-light interferometry, and scanning electron microscopy. An organotypic culture was then performed using a chicken epithelium model to simulate peri-implant soft tissue. We measured the contact angle, hydrophobicity, and roughness of the materials as well as the tissue behavior at their surfaces (cell migration and cell adhesion). Results The best cell migration was observed on ZrO2 ceramic. Cell adhesion was also drastically lower on the polished ZrO2 ceramic than on both the raw and polished LS2. Evaluating various surface topographies of LS2 showed that increasing surface roughness improved cell adhesion, leading to an increase of up to 13%. Conclusions Our results demonstrate that a biomaterial, here LS2, can be modified using simple surface changes in order to finely modulate soft tissue adhesion. Strong adhesion at the abutment associated with weak migration assists in gingival wound healing. On the same material, polishing can reduce cell adhesion without drastically modifying cell migration. A comparison of LS2 and ZrO2 ceramic showed that LS2 was more conducive to creating varying tissue reactions. Our results can help dental surgeons to choose, especially for esthetic implant abutments, the most appropriate biomaterial as well as the most appropriate surface treatment to use in accordance with specific clinical

  2. Temperature induced complementary switching in titanium oxide resistive random access memory

    Energy Technology Data Exchange (ETDEWEB)

    Panda, D., E-mail: dpanda@nist.edu [Department of Electronics Engineering, National Institute of Science and Technology, Berhampur, Odisha 761008 (India); Department of Electronics Engineering and Institute of Electronics, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Simanjuntak, F. M.; Tseng, T.-Y. [Department of Electronics Engineering and Institute of Electronics, National Chiao Tung University, Hsinchu 30010, Taiwan (China)

    2016-07-15

    On the way towards high memory density and computer performance, a considerable development in energy efficiency represents the foremost aspiration in future information technology. Complementary resistive switch consists of two antiserial resistive switching memory (RRAM) elements and allows for the construction of large passive crossbar arrays by solving the sneak path problem in combination with a drastic reduction of the power consumption. Here we present a titanium oxide based complementary RRAM (CRRAM) device with Pt top and TiN bottom electrode. A subsequent post metal annealing at 400°C induces CRRAM. Forming voltage of 4.3 V is required for this device to initiate switching process. The same device also exhibiting bipolar switching at lower compliance current, Ic <50 μA. The CRRAM device have high reliabilities. Formation of intermediate titanium oxi-nitride layer is confirmed from the cross-sectional HRTEM analysis. The origin of complementary switching mechanism have been discussed with AES, HRTEM analysis and schematic diagram. This paper provides valuable data along with analysis on the origin of CRRAM for the application in nanoscale devices.

  3. Laser beam joining of non-oxidic ceramics for ultra high temperature resistant joints

    International Nuclear Information System (INIS)

    Lippmann, W.; Knorr, J.; Wolf, R.; Reinecke, A.M.; Rasper, R.

    2004-01-01

    The excellent technical properties of silicon carbide (SiC) and silicon nitride (Si 3 N 4 ) ceramics, such as resistance to extreme temperatures, oxidation, mechanical wear, aggressive chemical substances and radioactive radiation and also its high thermal conductivity and good temperature-shock resistance, make these ceramics ideally suited for use in the field of nuclear technology. However, their practical use has been limited so far because of the unavailability of effective joining techniques for these ceramics, especially for high temperature applications. A new joining technology (CERALINK registered ) has been developed in a network project which allowed high temperature resistant and vacuum-tight joining of SiC or Si 3 N 4 ceramics. A power laser is used as heat source, which makes it possible to join ceramic components in free atmosphere in combination with a pure oxidic braze filler. As no furnace is necessary, there are no limitations on the component dimensions by the furnace-geometry. During the joining process, the heated area can be limited to the seam area so that this technology can also be used to encapsulate materials with a low melting point. The seam has a high mechanical strength, it is resistant to a wide range of chemicals and radiation and it is also vacuum-tight. The temperature resistance can be varied by variation of the braze filler composition - usually between 1,400 C and >1,600 C. Beside the optimum filler it is also important to select the suitable laser wavelength. The paper will demonstrate the influence of different wave lengths, i. e. various laser types, on the seam quality. Examples are chosen to illustrate the strengths and limitations of the new technology

  4. Nano-Ceramic Coated Plastics

    Science.gov (United States)

    Cho, Junghyun

    2013-01-01

    Plastic products, due to their durability, safety, and low manufacturing cost, are now rapidly replacing cookware items traditionally made of glass and ceramics. Despite this trend, some still prefer relatively expensive and more fragile ceramic/glassware because plastics can deteriorate over time after exposure to foods, which can generate odors, bad appearance, and/or color change. Nano-ceramic coatings can eliminate these drawbacks while still retaining the advantages of the plastic, since the coating only alters the surface of the plastic. The surface coating adds functionality to the plastics such as self-cleaning and disinfectant capabilities that result from a photocatalytic effect of certain ceramic systems. These ceramic coatings can also provide non-stick surfaces and higher temperature capabilities for the base plastics without resorting to ceramic or glass materials. Titanium dioxide (TiO2) and zinc oxide (ZnO) are the candidates for a nano-ceramic coating to deposit on the plastics or plastic films used in cookware and kitchenware. Both are wide-bandgap semiconductors (3.0 to 3.2 eV for TiO2 and 3.2 to 3.3 eV for ZnO), so they exhibit a photocatalytic property under ultraviolet (UV) light. This will lead to decomposition of organic compounds. Decomposed products can be easily washed off by water, so the use of detergents will be minimal. High-crystalline film with large surface area for the reaction is essential to guarantee good photocatalytic performance of these oxides. Low-temperature processing (nano-ceramic coatings (TiO2, ZnO) on plastic materials (silicone, Teflon, PET, etc.) that can possess both photocatalytic oxide properties and flexible plastic properties. Processing cost is low and it does not require any expensive equipment investment. Processing can be scalable to current manufacturing infrastructure.

  5. Gentamicin coating of plasma chemical oxidized titanium alloy prevents implant-related osteomyelitis in rats.

    Science.gov (United States)

    Diefenbeck, M; Schrader, C; Gras, F; Mückley, T; Schmidt, J; Zankovych, S; Bossert, J; Jandt, K D; Völpel, A; Sigusch, B W; Schubert, H; Bischoff, S; Pfister, W; Edel, B; Faucon, M; Finger, U

    2016-09-01

    Implant related infection is one of the most feared and devastating complication associated with the use of orthopaedic implant devices. Development of anti-infective surfaces is the main strategy to prevent implant contamination, biofilm formation and implant related osteomyelitis. A second concern in orthopaedics is insufficient osseointegration of uncemented implant devices. Recently, we reported on a macroporous titanium-oxide surface (bioactive TiOB) which increases osseointegration and implant fixation. To combine enhanced osseointegration and antibacterial function, the TiOB surfaces were, in addition, modified with a gentamicin coating. A rat osteomyelitis model with bilateral placement of titanium alloy implants was employed to analyse the prophylactic effect of gentamicin-sodiumdodecylsulfate (SDS) and gentamicin-tannic acid coatings in vivo. 20 rats were randomly assigned to four groups: (A) titanium alloy; PBS inoculum (negative control), (B) titanium alloy, Staphylococcus aureus inoculum (positive control), (C) bioactive TiOB with gentamicin-SDS and (D) bioactive TiOB plus gentamicin-tannic acid coating. Contamination of implants, bacterial load of bone powder and radiographic as well as histological signs of implant-related osteomyelitis were evaluated after four weeks. Gentamicin-SDS coating prevented implant contamination in 10 of 10 tibiae and gentamicin-tannic acid coating in 9 of 10 tibiae (infection prophylaxis rate 100% and 90% of cases, respectively). In Group (D) one implant showed colonisation of bacteria (swab of entry point and roll-out test positive for S. aureus). The interobserver reliability showed no difference in the histologic and radiographic osteomyelitis scores. In both gentamicin coated groups, a significant reduction of the histological osteomyelitis score (geometric mean values: C = 0.111 ± 0.023; D = 0.056 ± 0.006) compared to the positive control group (B: 0.244 ± 0.015; p < 0.05) was observed. The

  6. A Novel Investigation of the Formation of Titanium Oxide Nanotubes on Thermally Formed Oxide of Ti-6Al-4V.

    Science.gov (United States)

    Butt, Arman; Hamlekhan, Azhang; Patel, Sweetu; Royhman, Dmitry; Sukotjo, Cortino; Mathew, Mathew T; Shokuhfar, Tolou; Takoudis, Christos

    2015-10-01

    Traditionally, titanium oxide (TiO2) nanotubes (TNTs) are anodized on Ti-6Al-4V alloy (Ti-V) surfaces with native TiO2 (amorphous TiO2); subsequent heat treatment of anodized surfaces has been observed to enhance cellular response. As-is bulk Ti-V, however, is often subjected to heat treatment, such as thermal oxidation (TO), to improve its mechanical properties. Thermal oxidation treatment of Ti-V at temperatures greater than 200°C and 400°C initiates the formation of anatase and rutile TiO2, respectively, which can affect TNT formation. This study aims at understanding the TNT formation mechanism on Ti-V surfaces with TO-formed TiO2 compared with that on as-is Ti-V surfaces with native oxide. Thermal oxidation-formed TiO2 can affect TNT formation and surface wettability because TO-formed TiO2 is expected to be part of the TNT structure. Surface characterization was carried out with field emission scanning electron microscopy, energy dispersive x-ray spectroscopy, water contact angle measurements, and white light interferometry. The TNTs were formed on control and 300°C and 600°C TO-treated Ti-V samples, and significant differences in TNT lengths and surface morphology were observed. No difference in elemental composition was found. Thermal oxidation and TO/anodization treatments produced hydrophilic surfaces, while hydrophobic behavior was observed over time (aging) for all samples. Reduced hydrophobic behavior was observed for TO/anodized samples when compared with control, control/anodized, and TO-treated samples. A method for improved surface wettability and TNT morphology is therefore discussed for possible applications in effective osseointegration of dental and orthopedic implants.

  7. Ceramic coated Y1 magnesium alloy surfaces by microarc oxidation

    Indian Academy of Sciences (India)

    The magnesium alloys occupy an important place in marine applications, but their poor corrosion resistance, wear resistance, hardness and so on, have limited their application. To meet these defects, some techniques are developed. Microarc oxidation is a one such recently developed surface treatment technology under ...

  8. Study on the efficiency of ceramic coating for avoiding oxidation in carbon refractories

    International Nuclear Information System (INIS)

    Santos, I.M.G.; Cruz Junior, F.; Paskocimas, C.A.; Leite, E.R.; Longo, Elson; Varela, J.A.

    1997-01-01

    A ceramic coating made of sodium phosphossilicate and clay was developed to the protection of refractories against carbon oxidation during the pre-heating of siderurgical equipment. This search has the objective of comparing the refractory behaviour with and without coating, according to temperature, time and atmosphere. The results show that the coating is more efficient at higher temperatures. An important point is that the efficiency is smaller after long thermal is that the efficiency is smaller after long thermal treatments and at very aggressive conditions. In spite of this the oxidation is still smaller than in refractory without coating. (author)

  9. Creep performance of oxide ceramic fiber materials at elevated temperature in air and in steam

    Science.gov (United States)

    Armani, Clinton J.

    Structural aerospace components that operate in severe conditions, such as extreme temperatures and detrimental environments, require structural materials that have superior long-term mechanical properties and that are thermochemically stable over a broad range of service temperatures and environments. Ceramic matrix composites (CMCs) capable of excellent mechanical performance in harsh environments are prime candidates for such applications. Oxide ceramic materials have been used as constituents in CMCs. However, recent studies have shown that high-temperature mechanical performance of oxide-oxide CMCs deteriorate in a steam-rich environment. The degradation of strength at elevated temperature in steam has been attributed to the environmentally assisted subcritical crack growth in the oxide fibers. Furthermore, oxide-oxide CMCs have shown significant increases in steady-state creep rates in steam. The present research investigated the effects of steam on the high-temperature creep and monotonic tension performance of several oxide ceramic materials. Experimental facilities were designed and configured, and experimental methods were developed to explore the influence of steam on the mechanical behaviors of ceramic fiber tows and of ceramic bulk materials under temperatures in the 1100--1300°C range. The effects of steam on creep behavior of Nextel(TM)610 and Nextel(TM)720 fiber tows were examined. Creep rates at elevated temperatures in air and in steam were obtained for both types of fibers. Relationships between creep rates and applied stresses were modeled and underlying creep mechanisms were identified. For both types of fiber tows, a creep life prediction analysis was performed using linear elastic fracture mechanics and a power-law crack velocity model. These results have not been previously reported and have critical design implications for CMC components operating in steam or near the recommended design limits. Predictions were assessed and validated via

  10. Surface oxidation of porous ZrB2-SiC ceramic composites by continuous-wave ytterbium fibre laser

    International Nuclear Information System (INIS)

    Mahmod, Dayang Salyani Abang; Glandut, Nicolas; Khan, Amir Azam; Labbe, Jean-Claude

    2015-01-01

    Highlights: • Surface oxidation of ZrB 2 -SiC ceramic composites by Yb-fibre laser. • Round spiral laser pattern created for the surface oxidation. • Presence of laser-formed oxide scale and unaffected beneath regions. • Crazed but uncracked surface oxide. • A dense glassy SiO 2 -rich layer exhibited enhances oxidation resistance. - Abstract: Surface treatment of ceramic substrates by a laser beam can allow to incorporate interesting properties to these ceramics. In the present work, surface oxidation of ca. 30% porous ZrB 2 -SiC ceramic composites by using an ytterbium fibre laser was conducted. Oxidation of ceramic substrates through this process under ambient conditions has certain advantages compared to the classical oxidation method. A particular spiral laser pattern was created in order to produce an oxidized structure on ZrB 2 -SiC porous substrates. The laser parameters were as follows i.e., laser power of 50, 60 and 70 W, a beam diameter of 1.25 mm, velocity of 2 mm/s, acceleration and deceleration of 1 mm/s 2 . The microstructural and morphological changes in the laser-treated region was examined using scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. At laser power of 70 W, the sample exhibits uniform oxidation. It revealed that the very porous bulk beneath remained unaffected and unoxidized because this laser-formed oxide scale protects the substrate from oxidation. The presence of oxidized and unaffected regions indicated a high degree of heat localization. The dense glassy SiO 2 -rich layer prevents the inward oxygen diffusion into the inner bulk hence enhances the oxidation resistance.

  11. Sulfonation degree effect on ion-conducting SPEEK-titanium oxide membranes properties

    Energy Technology Data Exchange (ETDEWEB)

    Marrero, Jacqueline Costa; Gomes, Ailton de Souza; Dutra Filho, José Carlos, E-mail: jacquecosta@gmail.com [Universidade Federal do Rio de Janeiro (IMA/UFRJ), RJ (Brazil). Instituto de Macromoléculas Professora Eloisa Mano; Hui, Wang Shu [Universidade de São Paulo (USP), São Paulo, SP (Brazil). Departamento de Engenharia Metalúrgica e de Materiais; Oliveira, Vivianna Silva de [Escola Técnica Rezende Rammel (ETRR), Rio de Janeiro, RJ (Brazil)

    2017-07-01

    Polymeric membranes were developed using a SPEEK (sulfonated poly(ether ether ketone)) polymer matrix, containing titanium oxide (TiO{sub 2}) (incorporated by sol-gel method). SPEEK with different sulfonation degrees (SD): 63% and 50% were used. The influence of sulfonation degree on membrane properties was investigated. The thermal analysis (TGA and DTGA) and X-ray diffraction (XRD) were carried out to characterize the membranes and electrochemical impedance spectroscopy (EIS) was carried out to evaluate the proton conductivity of the membranes. The proton conductivities in water were of 3.25 to 37.08 mS.cm{sup -1}. Experimental data of impedance spectroscopy were analyzed with equivalent circuits using the Zview software, and the results showed that, the best fitted was at 80 °C. (author)

  12. Behind the Nature of Titanium Oxide Excellent Surface Passivation and Carrier Selectivity of c-Si

    DEFF Research Database (Denmark)

    Plakhotnyuk, Maksym; Crovetto, Andrea; Hansen, Ole

    We present an expanded study of the passivation properties of titanium dioxide (TiO2) on p-type crystalline silicon (c-Si). We report a low surface recombination velocity (16 cm/s) for TiO2 passivation layers with a thin tunnelling oxide interlayer (SiO2 or Al2O3) on p-type crystalline silicon (c-Si......), and post-deposition annealing temperature were investigated. We have observed that that SiO2 and Al2O3 interlayers enhance the TiO2 passivation of c-Si. TiO2 thin film passivation layers alone result in lower effective carrier lifetime. Further annealing at 200  ̊C in N2 gas enhances the surface...

  13. A study of nitride formation during the oxidation of titanium-tantalum alloys

    International Nuclear Information System (INIS)

    Hanrahan, R.J. Jr.; Lu, Y.C.; Kung, H.; Butt, D.P.

    1996-01-01

    The oxidation rates of Ti rich titanium-tantalum alloys are significantly lower in air than in oxygen. This nitrogen effect has been shown to be associated with the formation of a nitride layer at or near the scale-metal interface. In the present work the authors used transmission electron microscopy and microdiffraction to identify the nitrides formed on Ti5Ta and Ti40Ta (5 and 40 weight percent Ta alloys) during identical exposures. In both alloys the nitride develops in contact with the oxygen stabilized α-phase in the substrate. In Ti5Ta a continuous layer of TiN forms, while in Ti40Ta a discontinuous layer of Ti 2 N interspersed with Ta 2 O 5 (formed from the Ta rich β-phase) is formed. The nitride layer acts as an oxygen diffusion barrier, reducing the dissolution of oxygen in the substrate

  14. Enabling new sensor applications for (V)HTRS by laser hybrid brazing of oxide ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Heilmann, F.; Rixecker, G. [Robert Bosch GmbH, Stuttgart (Germany). Corporate Research and Development; Herrmann, M.; Lippmann, W.; Hurtado, A. [Univ. of Technology, Dresden (Germany). Chair of Hydrogen- and Nuclear Engineering

    2008-07-01

    The use of (very) high temperature reactors ((V)HTRs) requires a sensor technology suitable to withstand thermal loads both in normal operation mode and under incident conditions which may appear during service. Especially ceramic sensors are ideal to suit this purpose. A special sensor type that is based upon oxide ceramics is the high temperature oxygen sensor. Base material for this application is yttria-doped zirconia. At elevated temperatures (above 450 C) the activation energy of oxygen ions is sufficient to migrate in the ZrO{sub 2} lattice following an oxygen partial pressure gradient. This diffusion process is facilitated by the trivalent yttrium ions which give rise to a high concentration of oxygen vacancies. The macroscopical effect of the migration of the oxygen ions can be detected as a Nernst voltage or, alternatively, as an electrical current. Thus it is possible to compare the oxygen content of measured media with that of a known reference gas. To be able to produce such sensors both efficiently and in the desired quality, joining technologies adapted to ceramics are necessary. Laser-based technologies for brazing with glass or glass-ceramic solders are especially suitable, as they combine high precision with high throughput. They thus enable cost efficient production processes both for large and small lot sizes. (orig.)

  15. The characterization of an oxide interfacial coating for ceramic matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Coons, Timothy P., E-mail: tpcoons@gmail.com [Department of Chemistry, Unit 3060, University of Connecticut, 55 North Eagleville Road, Storrs, CT 06269-3060 (United States); Reutenauer, Justin W.; Mercado, Andrew [Department of Chemistry, Unit 3060, University of Connecticut, 55 North Eagleville Road, Storrs, CT 06269-3060 (United States); Kmetz, Michael A. [Pratt and Whitney, 400 Main Street M/S 114-43, East Hartford, CT 06108 (United States); Suib, Steven L. [Department of Chemistry, Unit 3060, University of Connecticut, 55 North Eagleville Road, Storrs, CT 06269-3060 (United States)

    2013-06-20

    This work focused on the use of metal organic chemical vapor deposition (MOCVD) to deposit a zinc oxide (ZnO) coating on ceramic fibers as an interfacial system for continuous fiber reinforced ceramic matrix composites (CFR-CMCs). ZnO coatings were deposited on ceramic grade (CG) Nicalon{sup ™}, Hi-Nicalon{sup ™}, and Hi-Nicalon{sup ™} Type S fabric by the thermal decomposition of zinc acetate dihydrate in a low pressure hot wall CVD reactor. A duplex SiO{sub 2} coating was also deposited in order to protect the ZnO layer from the reducing conditions during composite fabrication. Tow testing was used to evaluate the effect of the ZnO coating on the strength retention of the ceramic fabrics. Single strand unidirectional mini composites were fabricated by infiltrating SiC into the ZnO/SiO{sub 2} duplex coated tows in order to understand the interfacial properties of the ZnO coating. The mini composite utilizing Hi-Nicalon{sup ™} Type S produced the highest ultimate tensile strength (UTS) of 330 MPa. The coated fabrics and the mini composites were characterized using field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and scanning Auger microscopy (SAM)

  16. The characterization of an oxide interfacial coating for ceramic matrix composites

    International Nuclear Information System (INIS)

    Coons, Timothy P.; Reutenauer, Justin W.; Mercado, Andrew; Kmetz, Michael A.; Suib, Steven L.

    2013-01-01

    This work focused on the use of metal organic chemical vapor deposition (MOCVD) to deposit a zinc oxide (ZnO) coating on ceramic fibers as an interfacial system for continuous fiber reinforced ceramic matrix composites (CFR-CMCs). ZnO coatings were deposited on ceramic grade (CG) Nicalon ™ , Hi-Nicalon ™ , and Hi-Nicalon ™ Type S fabric by the thermal decomposition of zinc acetate dihydrate in a low pressure hot wall CVD reactor. A duplex SiO 2 coating was also deposited in order to protect the ZnO layer from the reducing conditions during composite fabrication. Tow testing was used to evaluate the effect of the ZnO coating on the strength retention of the ceramic fabrics. Single strand unidirectional mini composites were fabricated by infiltrating SiC into the ZnO/SiO 2 duplex coated tows in order to understand the interfacial properties of the ZnO coating. The mini composite utilizing Hi-Nicalon ™ Type S produced the highest ultimate tensile strength (UTS) of 330 MPa. The coated fabrics and the mini composites were characterized using field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and scanning Auger microscopy (SAM)

  17. Biomimetic routes to nanoscale-toughened oxide ceramics

    Science.gov (United States)

    Deschaume, Olivier

    In this work, a novel anion exchange technique has been developed and optimised in order to prepare extra-pure, hydroxide-free solutions of aluminium polyoxocations (A113 and A130) as well as for the preparation of nanosized, highly monodisperse aluminium hydroxide particles in the particle size range 20-200nm. In order for the evolution and composition of the resulting systems to be monitored, an array of characterisation techniques including 27A1 NMR, dynamic light scattering, po-tentiometry, conductometry and UV-Vis spectroscopy, have been implemented and complemented with successful data treatment strategies. The quantitative data obtained indicates that the static anion exchange method is a soft, environmentally friendly, low-cost, energy-saving and convenient procedure for the preparation of Al- containing model systems. The A1 species obtained can be used for high-precision model studies on A1 speciation, and serve as nanosize precursors to a variety of Al-containing materials. The use of these pure A1 precursors has a clear advantage in materials synthesis arising from an improved understanding and better control of A1 speciation. In a second development of the project, the model systems have been used in a nanotectonic approach to biomimetic materials synthesis, with possible applications to the optimisation of Al-containing materials such as ceramics or composite films. Bearing this aim in mind, the interactions of the prepared aluminium species with the model protein BSA and a bioelastomer, elastin, were monitored and the resulting composite materials characterised. The methodology developed for the synthesis and characterisation of pure A1 species and A1 species/biomolecule systems is a robust base for further studies spanning research fields such as Chemistry, Biology or Environmental sciences, and possess a large potential for application to industrial products and processes.

  18. Photoacoustic spectroscopy investigation of sintered zinc-tin-oxide ceramics

    Directory of Open Access Journals (Sweden)

    Ivetić Tamara B.

    2007-01-01

    Full Text Available In this paper the changes that occurred in differently activated ZnO-SnO2 and sintered samples were investigated using photoacoustic spectroscopy. ZnO and SnO2 powders, mixed in the molar ratio 2:1, were mechanically activated in a planetary ball mill for 10-160 min. The mixtures were pres­sed and isothermally sintered at 1300°C for two hours. X-ray diffraction analysis of the obtained sintered samples was performed in order to investigate changes of the phase composition and confirmed only the presence of a pure zinc stannate (Zn2SnO4 phase in all the sintered samples as a result of the solid state reaction and reaction sintering between the starting ZnO and SnO2 powders. The microstructure of the sintered sam­ples was examined by scanning electron microscopy and showed that mechanical activation leads to the formation of a structure with reduced particle size which accelerates spinel formation. Grain growth of the spinel phase slows down the densification process and together with the agglomerates formed during mechanical activation causes the appearance of a porous microstructure. The photoacoustic (PA phase and amplitude spectra of the sintered samples were recorded as a function of the chopped frequency of the laser beam used (red laser with a power of 25 mW, λ=632 nm in a thermal-transmission detection configuration. PA experimental data were analyzed using the Rosenzweig-Gersho thermal-piston model, which enabled determination of the thermal diffusivity, ZT (m2s-1, diffusion coefficient of the minority free carriers D (m2s-1 and the optical absorption coefficient (m-1. The detected differences of the measured thermal-electrical properties of the obtained Zn2SnO4 ceramics indicate changes in the material induced by the different preparation procedure of the starting powders before the sintering process.

  19. Fabrication and oxidation resistance of titanium carbide-coated carbon fibres by reacting titanium hydride with carbon fibres in molten salts

    International Nuclear Information System (INIS)

    Dong, Z.J.; Li, X.K.; Yuan, G.M.; Cong, Y.; Li, N.; Jiang, Z.Y.; Hu, Z.J.

    2009-01-01

    Using carbon fibres and titanium hydride as a reactive carbon source and a metal source, respectively, a protective titanium carbide (TiC) coating was formed on carbon fibres in molten salts, composed of LiCl-KCl-KF, at 750-950 o C. The structure and morphology of the TiC coatings were characterised by X-ray diffraction and scanning electron microscopy, respectively. The oxidation resistance of the TiC-coated carbon fibres was measured by thermogravimetric analysis. The results reveal that control of the coating thickness is very important for improvement of the oxidation resistance of TiC-coated carbon fibres. The oxidative weight loss initiation temperature for the TiC-coated carbon fibres increases significantly when an appropriate coating thickness is used. However, thicker coatings lead to a decrease of the carbon fibres' weight loss initiation temperature due to the formation of cracks in the coating. The TiC coating thickness on carbon fibres can be controlled by adjusting the reaction temperature and time of the molten salt synthesis.

  20. Molten salt synthesis of sodium lithium titanium oxide anode material for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Yin, S.Y., E-mail: yshy2004@hotmail.com [College of Environmental and Biological Engineering, Wuhan Technology and Business University, Wuhan 430065 (China); Feng, C.Q. [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry of Education Key Laboratory for Synthesis and Applications of Organic Functional Molecules, Hubei University, Wuhan 430062 (China); Wu, S.J.; Liu, H.L.; Ke, B.Q. [College of Environmental and Biological Engineering, Wuhan Technology and Business University, Wuhan 430065 (China); Zhang, K.L. [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Chen, D.H. [College of Environmental and Biological Engineering, Wuhan Technology and Business University, Wuhan 430065 (China); Hubei Key Laboratory for Catalysis and Material Science, College of Chemistry and Material Science, South Central University for Nationalities, Wuhan 430074, Hubei (China)

    2015-09-05

    Highlights: • Na{sub 2}Li{sub 2}Ti{sub 6}O{sub 12} has been successfully synthesized via a molten salt route. • Calcination temperature is an important effect on the component and microstructure of the product. • Pure phase Na{sub 2}Li{sub 2}Ti{sub 6}O{sub 12} could be obtained at 700 °C for 2 h. - Abstract: The sodium lithium titanium oxide with composition Na{sub 2}Li{sub 2}Ti{sub 6}O{sub 14} has been synthesized by a molten salt synthesis method using sodium chloride and potassium chloride mixture as a flux medium. Synthetic variables on the synthesis, such as sintering temperature, sintering time and the amount of lithium carbonate, were intensively investigated. Powder X-ray diffraction and scanning electron microscopy images of the reaction products indicates that pure phase sodium lithium titanium oxide has been obtained at 700 °C, and impure phase sodium hexatitanate with whiskers produced at higher temperature due to lithium evaporative losses. The results of cyclic voltammetry and discharge–charge tests demonstrate that the synthesized products prepared at various temperatures exhibited electrochemical diversities due to the difference of the components. And the sample obtained at 700 °C revealed highly reversible insertion and extraction of Li{sup +} and displayed a single potential plateau at around 1.3 V. The product obtained at 700 °C for 2 h exhibits good cycling properties and retains the specific capacity of 62 mAh g{sup −1} after 500 cycles.

  1. Stannic Oxide-Titanium Dioxide Coupled Semiconductor Photocatalyst Loaded with Polyaniline for Enhanced Photocatalytic Oxidation of 1-Octene

    Directory of Open Access Journals (Sweden)

    Hadi Nur

    2007-01-01

    Full Text Available Stannic oxide-titanium dioxide (SnO2–TiO2 coupled semiconductor photocatalyst loaded with polyaniline (PANI, a conducting polymer, possesses a high photocatalytic activity in oxidation of 1-octene to 1,2-epoxyoctane with aqueous hydrogen peroxide. The photocatalyst was prepared by impregnation of SnO2 and followed by attachment of PANI onto a TiO2 powder to give sample PANI-SnO2–TiO2. The electrical conductivity of the system becomes high in the presence of PANI. Enhanced photocatalytic activity was observed in the case of PANI-SnO2–TiO2 compared to PANI-TiO2, SnO2–TiO2, and TiO2. A higher photocatalytic activity in the oxidation of 1-octene on PANI-SnO2–TiO2 than SnO2–TiO2, PANI-TiO2, and TiO2 can be considered as an evidence of enhanced charge separation of PANI-SnO2–TiO2 photocatalyst as confirmed by photoluminescence spectroscopy. It suggests that photoinjected electrons are tunneled from TiO2 to SnO2 and then to PANI in order to allow wider separation of excited carriers.

  2. The effect of titanium nickel nitride decorated carbon nanotubes-reduced graphene oxide hybrid support for methanol oxidation

    Science.gov (United States)

    Liu, Gen; Pan, Zhanchang; Li, Wuyi; Yu, Ke; Xia, Guowei; Zhao, Qixiang; Shi, Shikun; Hu, Guanghui; Xiao, Chumin; Wei, Zhigang

    2017-07-01

    Titanium nickel nitride (TiNiN) decorated three-dimensional (3D) carbon nanotubes-reduced graphene oxide (CNT-rGO), a fancy 3D platinum (Pt)-based catalyst hybrid support, is prepared by a solvothermal process followed by a nitriding process, which is tested as anodic catalyst support for the methanol oxidation reaction (MOR). The structure, morphology and composition of the synthesized TiNiN/CNT-rGO exhibits a uniform particle dispersion with high purity and interpenetrating 3D network structure. Notably, Pt/TiNiN/CNT-rGO catalyst exhibits significantly improved catalytic activity and durability for methanol oxidation in comparison with Pt/CNT-rGO and conventional Pt/C (JM). The outstanding electrochemical performance was attributed to structure and properties. That is, the 3D CNT-rGO provided a fast transport network for charge-transfer and mass-transfer as well as TiNiN NPs with good synergistic effect and the strong electronic coupling between different domains in TiNiN/CNT-rGO, thus the catalytic activity of the novel catalyst is greatly improved. These results evidences 3D TiNiN/CNT-rGO as a promising catalyst support for a wide range of applications in fuel cells.

  3. The role of surface oxides on hydrogen sorption kinetics in titanium thin films

    Science.gov (United States)

    Hadjixenophontos, Efi; Michalek, Lukas; Roussel, Manuel; Hirscher, Michael; Schmitz, Guido

    2018-05-01

    Titanium is presently discussed as a catalyst to accelerate the hydrogenation kinetics of hydrogen storage materials. It is however known that H absorption in Ti decisively depends on the surface conditions (presence or absence of the natural surface oxide). In this work, we use Ti thin films of controlled thickness (50-800 nm) as a convenient tool for quantifying the atomic transport. XRD and TEM investigations allow us to follow the hydrogenation progress inside the film. Hydrogenation of TiO2/Ti bi-layers is studied at 300 °C, for different durations (10 s to 600 min) and at varying pressures of pure H2 atmosphere. Under these conditions, the hydrogenation is found to be linear in time. By comparing films with and without TiO2, as well as by studying the pressure dependence of hydrogenation, it is demonstrated that hydrogen transport across the oxide represents the decisive kinetic barrier rather than the splitting of H2 molecules at the surface. Hydrogenation appears by a layer-like reaction initiated by heterogeneous nucleation at the backside interface to the substrate. The linear growth constant and the H diffusion coefficient inside the oxide are quantified, as well as a reliable lower bound to the hydrogen diffusion coefficient in Ti is derived. The pressure dependence of hydrogen absorption is quantitatively modelled.

  4. 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.

  5. [Apatite-forming ability of pure titanium implant after micro-arc oxidation treatment].

    Science.gov (United States)

    Tian, Zhihui; Zhang, Yu; Wang, Lichao; Nan, Kaihui

    2013-10-01

    To investigate the apatite forming ability of pure titanium implant after micro-arc oxidation treatment in simulated body fluid (SBF) and obtain implants with calcium phosphate (Ca-P) layers. The implants were immersed in (SBF) after micro-arc oxidation treatment for different time lengths, and their apatite forming ability and the morphology and constituents of the Ca-P layers formed on the sample surface were analyzed using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and energy dispersive electron probe. After immersion in SBF, large quantities of Ca-P layers were induced on the surface of the samples. The Ca-P layers were composed of octacalcium phosphate and carbonated hydroxyapatite, and the crystals showed a plate-like morphology with an oriented growth. The implants with micro-arc oxidation treatment show good apatite forming ability on the surface with rich calcium and phosphorus elements. The formed layers are composed of bone-like apatite including octacalcium phosphate and carbonated hydroxyapatite.

  6. Comparison of Oxidative Stresses Mediated by Different Crystalline Forms and Surface Modification of Titanium Dioxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Karim Samy El-Said

    2015-01-01

    Full Text Available Titanium dioxide nanoparticles (TiO2 NPs are manufactured worldwide for use in a wide range of applications. There are two common crystalline forms of TiO2 anatase and rutile with different physical and chemical characteristics. We previously demonstrated that an increased DNA damage response is mediated by anatase crystalline form compared to rutile. In the present study, we conjugated TiO2 NPs with polyethylene glycol (PEG in order to reduce the genotoxicity and we evaluated some oxidative stress parameters to obtain information on the cellular mechanisms of DNA damage that operate in response to TiO2 NPs different crystalline forms exposure in hepatocarcinoma cell lines (HepG2. Our results indicated a significant increase in oxidative stress mediated by the anatase form of TiO2 NPs compared to rutile form. On the other hand, PEG modified TiO2 NPs showed a significant decrease in oxidative stress as compared to TiO2 NPs. These data suggested that the genotoxic potential of TiO2 NPs varies with crystalline form and surface modification.

  7. Ceramic joining

    Energy Technology Data Exchange (ETDEWEB)

    Loehman, R.E. [Sandia National Lab., Albuquerque, NM (United States)

    1996-04-01

    This paper describes the relation between reactions at ceramic-metal interfaces and the development of strong interfacial bonds in ceramic joining. Studies on a number of systems are described, including silicon nitrides, aluminium nitrides, mullite, and aluminium oxides. Joints can be weakened by stresses such as thermal expansion mismatch. Ceramic joining is used in a variety of applications such as solid oxide fuel cells.

  8. Viability of oxide fiber coatings in ceramic composites for accommodation of misfit stresses

    International Nuclear Information System (INIS)

    Kerans, R.J.

    1996-01-01

    The C and BN fiber coatings used in most ceramic composites perform a less obvious but equally essential function, in addition to crack deflection; they accommodate misfit stresses due to interfacial fracture surface roughness. Coatings substituted for them must also perform that function to be effective. However, in general, oxides are much less compliant materials than C and BN, which raises the question of the feasibility of oxide substitutes. The viability of oxide coatings for accommodating misfit stresses in Nicalon fiber/SiC composites was investigated by calculating the maximum misfit stresses as functions of coating properties and geometries. Control of interfacial fracture path was also briefly considered. The implications regarding composite properties were examined by calculating properties for composites with mechanically viable oxide coatings

  9. Photocatalytic oxidation of organic compounds via waveguide-supported titanium dioxide films

    Science.gov (United States)

    Miller, Lawrence W.

    A photochemical reactor based on titanium dioxide (TiO2)-coated silica optical fibers was constructed to explore the use of waveguide-supported TiO2 films for photocatalytic oxidation of organic compounds. The reactor was used for the photocatalytic oxidation of 4-chlorophenol in water. It was confirmed that TiO2 films could be securely attached to silica optical fibers. The 4-chlorophenol (100 mumol/L in water) was successfully oxidized on the TiO2 surface when UV light (310 nm--380 nm) was propagated through the fibers to the films. Rates of 4-chlorophenol oxidation and UV light flux to the fibers were measured. The quantum efficiency of 4-chlorophenol oxidation [defined as the change in 4-chlorophenol concentration divided by the UV light absorbed by the catalyst] was determined as a function of TiO2 catalyst film thickness and internal incident angle of propagating UV light. A maximum quantum efficiency of 2.8% was measured when TiO2 film thickness was ca. 80 nm and the maximum internal incident angle of propagating light was 84°. Quantum efficiency increased with increasing internal angle of incidence of propagating light and decreased with TiO2 film thickness. UV-Visible internal reflection spectroscopy was used to determine whether UV light propagated through TiO2-coated silica waveguides in an ATR mode. Propagation of UV light in an ATR mode was confirmed by the similarities between internal reflection spectra of phenolphthalein obtained with uncoated and TiO2-coated silica crystals. Planar silica waveguides coated with TiO2 were employed in a photocatalytic reactor for the oxidation of formic acid (833 mumol/L in water). It was shown that the quantum yield of formic acid oxidation [defined as the moles of formic acid oxidized divided by the moles of UV photons absorbed by the catalyst] on the waveguide-supported TiO2 surface is enhanced when UV light propagates through the waveguides in an ATR mode. A maximum quantum yield of 3.9% was found for formic

  10. Oxidative Stress, Inflammation, and DNA Damage Responses Elicited by Silver, Titanium Dioxide, and Cerium Oxide Nanomaterials

    Science.gov (United States)

    Previous literature on the biological effects of engineered nanomaterials has focused largely on oxidative stress and inflammation endpoints without further investigating potential pathways. Here we examine time-sensitive biological response pathways affected by engineered nanoma...

  11. Characterization of natural organic matter treated by iron oxide nanoparticle incorporated ceramic membrane-ozonation process.

    Science.gov (United States)

    Park, Hosik; Kim, Yohan; An, Byungryul; Choi, Heechul

    2012-11-15

    In this study, changes in the physical and structural properties of natural organic matter (NOM) were observed during hybrid ceramic membrane processes that combined ozonation with ultrafiltration ceramic membrane (CM) or with a reactive ceramic membrane (RM), namely, an iron oxide nanoparticles (IONs) incorporated-CM. NOM from feed water and NOM from permeate treated with hybrid ceramic membrane processes were analyzed by employing several NOM characterization techniques. Specific ultraviolet absorbance (SUVA), high-performance size exclusion chromatography (HPSEC) and fractionation analyses showed that the hybrid ceramic membrane process effectively removed and transformed relatively high contents of aromatic, high molecular weight and hydrophobic NOM fractions. Fourier transform infrared spectroscopy (FTIR) and 3-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy revealed that this process caused a significant decrease of the aromaticity of humic-like structures and an increase in electron withdrawing groups. The highest removal efficiency (46%) of hydroxyl radical probe compound (i.e., para-Chlorobenzoic acid (pCBA)) in RM-ozonation process compared with that in CM without ozonation process (8%) revealed the hydroxyl radical formation by the surface-catalyzed reaction between ozone and IONs on the surface of RM. In addition, experimental results on flux decline showed that fouling of RM-ozonation process (15%) was reduced compared with that of CM without ozonation process (30%). These results indicated that the RM-ozonation process enhanced the destruction of NOM and reduced the fouling by generating hydroxyl radicals from the catalytic ozonation in the RM-ozonation process. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. The Y2BaCuO5 oxide as green pigment in ceramics

    International Nuclear Information System (INIS)

    Fernandez, F.; Colon, C.; Duran, A.; Barajas, R.; Llopis, J.; Paje, S.E.; Saez-Puche, R.; Julian, I.

    1998-01-01

    Fine particles of green yttrium-barium-copper-oxide pigments Y 2 BaCuO 5 have been prepared using two different synthesis methods. The process of combustion of mixed nitrates and urea needs a maximal temperature of 900 C and provides samples formed by aggregates of homogeneous small particles with a size of about 0.3 μm. However, the ceramic method requires 1050 C as synthesis temperature, and yields rather higher particle sizes. Even after grinding, these samples are formed by heterogeneous particles with mean sizes of about 3 μm. Diffuse reflectance spectra reveal that the samples obtained using the former method present a higher brilliancy, so they have been selected to be tested as green pigment in ceramics with good results. (orig.)

  13. Trace and surface analysis of ceramic layers of solid oxide fuel cells by mass spectrometry.

    Science.gov (United States)

    Becker, J S; Breuer, U; Westheide, J; Saprykin, A I; Holzbrecher, H; Nickel, H; Dietze, H J

    1996-06-01

    For the trace analysis of impurities in thick ceramic layers of a solid oxide fuel cell (SOFC) sensitive solid-state mass spectrometric methods, such as laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and radiofrequency glow discharge mass spectrometry (rf-GDMS) have been developed and used. In order to quantify the analytical results of LA-ICP-MS, the relative sensitivity coefficients of elements in a La(0.6)Sr(0.35)MnO(3) matrix have been determined using synthetic standards. Secondary ion mass spectrometry (SIMS) - as a surface analytical method - has been used to characterize the element distribution and diffusion profiles of matrix elements on the interface of a perovskite/Y-stabilized ZrO(2) layer. The application of different mass spectrometric methods for process control in the preparation of ceramic layers for the SOFC is described.

  14. Comparative Evaluation of Friction Resistance of Titanium, Stainless Steel, Ceramic and Ceramic with Metal Insert Brackets with Varying Dimensions of Stainless Steel Wire: An In vitro Multi-center Study.

    Science.gov (United States)

    Kumar, B Sunil; Miryala, Suresh; Kumar, K Kiran; Shameem, K; Regalla, Ravindra Reddy

    2014-09-01

    The orthodontist seeks an archwire-bracket combination that has both good biocompatibility and low friction. Hence, the aim of this multicenter in vitro study was to evaluate and compare the frictional resistance generated between titanium (Ti), stainless steel (SS), ceramic and ceramic with metal insert (CMI) brackets with SS wires of varying dimensions in a specially designed apparatus. The material used in this study were Ti, SS, Ceramic and CMI with 0.018″ slot manufactured with zero degree tip and -7° torque premolar brackets (3M, Unitek) and SS wires of varying dimensions (0.016″ round, 0.016 × 0.016″ square, 0.016 × 0.022″ rectangular and 0.017 × 0.025″ rectangular) used. The frictional resistance was measured using Instron Universal testing machine (Model no. 4301). The specimen population in each center composed each of 160 brackets and wires. Differences among the all bracket/wire combinations were tested using (one-way) ANOVA, followed by the student Newman Keuls multiple comparisons of means ranking (at P bracket in combination with 0.017 × 0.025″ SS rectangular wire produced significant force levels for an optimum orthodontic movement with least frictional resistance. Ti brackets have least resistance and rectangular wires produced significant force. These can be used to avoid hazards of Nickel. SS brackets revealed higher static frictional force values as the wire dimension increased and showed lower static friction than Ti brackets for all wires except the thicker wire. Our study recommends the preclusion of brackets with rough surface texture (Ti brackets) with SS ligature wire for ligating bracket and archwire are better to reduce friction.

  15. Dense ceramic membranes based on ion conducting oxides

    International Nuclear Information System (INIS)

    Fontaine, M.L.; Larring, Y.; Bredesen, R.; Norby, T.; Grande, T.

    2007-01-01

    This chapter reviews the recent progress made in the fields of high temperature oxygen and hydrogen separation membranes. Studies of membranes for oxygen separation are mainly focusing on materials design to improve flux, and to lesser extent, related to stability issues. High oxygen fluxes satisfying industrial requirements can be obtained but, for many materials, the surface exchange rate is limiting the performance. The current status on electrolyte-type and mixed proton and electron conducting membranes is outlined, highlighting materials with improved stability in typical applications as solid oxide fuel cell technology and gas separation. In our presentation more fundamental aspects related to transport properties, chemical and mechanical stability of membrane materials are also treated. It is concluded that a significantly better understanding of the long term effects of operation in chemical gradients is needed for these types of membrane materials. (authors)

  16. Oxidation resistant coatings for ceramic matrix composite components

    Energy Technology Data Exchange (ETDEWEB)

    Vaubert, V.M.; Stinton, D.P. [Oak Ridge National Lab., TN (United States); Hirschfeld, D.A. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States). Dept. of Materials and Metallurgical Engineering

    1998-11-01

    Corrosion resistant Ca{sub 0.6}Mg{sub 0.4}Zr{sub 4}(PO{sub 4}){sub 6} (CMZP) and Ca{sub 0.5}Sr{sub 0.5}Zr{sub 4}(PO{sub 4}){sub 6} (CS-50) coatings for fiber-reinforced SiC-matrix composite heat exchanger tubes have been developed. Aqueous slurries of both oxides were prepared with high solids loading. One coating process consisted of dipping the samples in a slip. A tape casting process has also been created that produced relatively thin and dense coatings covering a large area. A processing technique was developed, utilizing a pre-sintering step, which produced coatings with minimal cracking.

  17. Photo-oxidation of gaseous ethanol on photocatalyst prepared by acid leaching of titanium oxide/hydroxyapatite composite

    Energy Technology Data Exchange (ETDEWEB)

    Ono, Y., E-mail: ono-y@kanagawa-iri.go.jp [Mechanical and Material Engineering Division, Kanagawa Industrial Technology Center, Ebina, Kanagawa 243-0435 (Japan); Rachi, T.; Yokouchi, M.; Kamimoto, Y. [Mechanical and Material Engineering Division, Kanagawa Industrial Technology Center, Ebina, Kanagawa 243-0435 (Japan); Nakajima, A. [Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, Meguro, Tokyo 152-8552 (Japan); Okada, K. [Materials and Structures Laboratory, Tokyo Institute of Technology, Midori, Yokohama, Kanagawa 226-8503 (Japan)

    2013-06-01

    Highlights: ► Photocatalyst powder was prepared by acid leaching of TiO{sub 2}/apatite composite. ► The photocatalytic activity was evaluated from in situ FT-IR study using ethanol. ► Apatite in the composite had positive effect for the photo-oxidation of ethanol. ► The enhanced oxidation rate was explained by the difference in deactivation rate. - Abstract: Highly active photocatalysts were synthesized by leaching of heat-treated titanium dioxide (TiO{sub 2})/hydroxyapatite (HAp) powder with hydrochloric acid at 0.25, 0.50, 0.75 mol/l, and their photocatalytic activities were evaluated from in situ Fourier transform infrared (FT-IR) study of photo-oxidation of gaseous ethanol. By changing the acid concentration, the TiO{sub 2}/HAp composite had different atomic ratios of Ca/Ti (0.0–2.8) and P/Ti (0.3–2.1). It was found that phosphate group remained on the surface of TiO{sub 2} particle even in the sample treated with concentrated acid (0.75 mol/l). These acid-treated samples showed higher rates for ethanol photo-oxidation than the commercial TiO{sub 2} powder, Degussa P25. The highest rate was obtained in the TiO{sub 2}/HAp composite treated with the dilute (0.25 mol/l) acid in spite of its low content of TiO{sub 2} photocatalyst. This enhanced photocatalytic activity was attributed to the result that the deactivation with repeated injections of ethanol gas was suppressed in the TiO{sub 2}/HAp composites compared with the TiO{sub 2} powders.

  18. Photo-oxidation of gaseous ethanol on photocatalyst prepared by acid leaching of titanium oxide/hydroxyapatite composite

    International Nuclear Information System (INIS)

    Ono, Y.; Rachi, T.; Yokouchi, M.; Kamimoto, Y.; Nakajima, A.; Okada, K.

    2013-01-01

    Highlights: ► Photocatalyst powder was prepared by acid leaching of TiO 2 /apatite composite. ► The photocatalytic activity was evaluated from in situ FT-IR study using ethanol. ► Apatite in the composite had positive effect for the photo-oxidation of ethanol. ► The enhanced oxidation rate was explained by the difference in deactivation rate. - Abstract: Highly active photocatalysts were synthesized by leaching of heat-treated titanium dioxide (TiO 2 )/hydroxyapatite (HAp) powder with hydrochloric acid at 0.25, 0.50, 0.75 mol/l, and their photocatalytic activities were evaluated from in situ Fourier transform infrared (FT-IR) study of photo-oxidation of gaseous ethanol. By changing the acid concentration, the TiO 2 /HAp composite had different atomic ratios of Ca/Ti (0.0–2.8) and P/Ti (0.3–2.1). It was found that phosphate group remained on the surface of TiO 2 particle even in the sample treated with concentrated acid (0.75 mol/l). These acid-treated samples showed higher rates for ethanol photo-oxidation than the commercial TiO 2 powder, Degussa P25. The highest rate was obtained in the TiO 2 /HAp composite treated with the dilute (0.25 mol/l) acid in spite of its low content of TiO 2 photocatalyst. This enhanced photocatalytic activity was attributed to the result that the deactivation with repeated injections of ethanol gas was suppressed in the TiO 2 /HAp composites compared with the TiO 2 powders

  19. The effect of titanium nickel nitride decorated carbon nanotubes-reduced graphene oxide hybrid support for methanol oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Gen [School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, Guangdong 510006 (China); Pan, Zhanchang, E-mail: panzhanchang@163.com [School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, Guangdong 510006 (China); Li, Wuyi; Yu, Ke [School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, Guangdong 510006 (China); Xia, Guowei; Zhao, Qixiang; Shi, Shikun [Victory Giant Technology (Hui Zhou) Co., Ltd., Huizhou 516083 (China); Hu, Guanghui; Xiao, Chumin; Wei, Zhigang [School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, Guangdong 510006 (China)

    2017-07-15

    Highlights: • TiNiN/CNT-rGO support with an interactive three-dimensional structure and high surface area was synthesized. • Pt nanoparticles with small size were well dispersed on TiNiN/CNT-rGO support. • Pt/TiNiN/CNT-rGO shows remarkably enhanced methanol oxidation activity and durability. - Abstract: Titanium nickel nitride (TiNiN) decorated three-dimensional (3D) carbon nanotubes-reduced graphene oxide (CNT-rGO), a fancy 3D platinum (Pt)-based catalyst hybrid support, is prepared by a solvothermal process followed by a nitriding process, which is tested as anodic catalyst support for the methanol oxidation reaction (MOR). The structure, morphology and composition of the synthesized TiNiN/CNT-rGO exhibits a uniform particle dispersion with high purity and interpenetrating 3D network structure. Notably, Pt/TiNiN/CNT-rGO catalyst exhibits significantly improved catalytic activity and durability for methanol oxidation in comparison with Pt/CNT-rGO and conventional Pt/C (JM). The outstanding electrochemical performance was attributed to structure and properties. That is, the 3D CNT-rGO provided a fast transport network for charge-transfer and mass-transfer as well as TiNiN NPs with good synergistic effect and the strong electronic coupling between different domains in TiNiN/CNT-rGO, thus the catalytic activity of the novel catalyst is greatly improved. These results evidences 3D TiNiN/CNT-rGO as a promising catalyst support for a wide range of applications in fuel cells.

  20. The effect of titanium nickel nitride decorated carbon nanotubes-reduced graphene oxide hybrid support for methanol oxidation

    International Nuclear Information System (INIS)

    Liu, Gen; Pan, Zhanchang; Li, Wuyi; Yu, Ke; Xia, Guowei; Zhao, Qixiang; Shi, Shikun; Hu, Guanghui; Xiao, Chumin; Wei, Zhigang

    2017-01-01

    Highlights: • TiNiN/CNT-rGO support with an interactive three-dimensional structure and high surface area was synthesized. • Pt nanoparticles with small size were well dispersed on TiNiN/CNT-rGO support. • Pt/TiNiN/CNT-rGO shows remarkably enhanced methanol oxidation activity and durability. - Abstract: Titanium nickel nitride (TiNiN) decorated three-dimensional (3D) carbon nanotubes-reduced graphene oxide (CNT-rGO), a fancy 3D platinum (Pt)-based catalyst hybrid support, is prepared by a solvothermal process followed by a nitriding process, which is tested as anodic catalyst support for the methanol oxidation reaction (MOR). The structure, morphology and composition of the synthesized TiNiN/CNT-rGO exhibits a uniform particle dispersion with high purity and interpenetrating 3D network structure. Notably, Pt/TiNiN/CNT-rGO catalyst exhibits significantly improved catalytic activity and durability for methanol oxidation in comparison with Pt/CNT-rGO and conventional Pt/C (JM). The outstanding electrochemical performance was attributed to structure and properties. That is, the 3D CNT-rGO provided a fast transport network for charge-transfer and mass-transfer as well as TiNiN NPs with good synergistic effect and the strong electronic coupling between different domains in TiNiN/CNT-rGO, thus the catalytic activity of the novel catalyst is greatly improved. These results evidences 3D TiNiN/CNT-rGO as a promising catalyst support for a wide range of applications in fuel cells.

  1. Processing, Structure and High Temperature Oxidation Properties of Polymer-Derived and Hafnium Oxide Based Ceramic Systems

    Science.gov (United States)

    Terauds, Kalvis

    Demands for hypersonic aircraft are driving the development of ultra-high temperature structural materials. These aircraft, envisioned to sustain Mach 5+, are expected to experience continuous temperatures of 1200--1800°C on the aircraft surface and temperatures as high as 2800°C in combustion zones. Breakthroughs in the development of fiber based ceramic matrix composites (CMCs) are opening the door to a new class of high-tech UHT structures for aerospace applications. One limitation with current carbon fiber or silicon carbide fiber based CMC technology is the inherent problem of material oxidation, requiring new approaches for protective environmental barrier coatings (EBC) in extreme environments. This thesis focuses on the development and characterization of SiCN-HfO2 based ceramic composite EBC systems to be used as a protective layer for silicon carbide fiber based CMCs. The presented work covers three main architectures for protection (i) multilayer films, (ii) polymer-derived HfSiCNO, and (iii) composite SiCN-HfO 2 infiltration. The scope of this thesis covers processing development, material characterization, and high temperature oxidation behavior of these three SiCN-HfO2 based systems. This work shows that the SiCN-HfO 2 composite materials react upon oxidation to form HfSiO4, offering a stable EBC in streaming air and water vapor at 1600°C.

  2. Dye-sensitized solar cell architecture based on indium-tin oxide nanowires coated with titanium dioxide

    International Nuclear Information System (INIS)

    Joanni, Ednan; Savu, Raluca; Sousa Goes, Marcio de; Bueno, Paulo Roberto; Nei de Freitas, Jilian; Nogueira, Ana Flavia; Longo, Elson; Varela, Jose Arana

    2007-01-01

    A new architecture for dye-sensitized solar cells is employed, based on a nanostructured transparent conducting oxide protruding from the substrate, covered with a separate active oxide layer. The objective is to decrease electron-hole recombination. The concept was tested by growing branched indium-tin oxide nanowires on glass using pulsed laser deposition followed by deposition of a sputtered titanium dioxide layer covering the wires. The separation of charge generation and charge transport functions opens many possibilities for dye-sensitized solar cell optimization

  3. Investigating the structure and biocompatibility of niobium and titanium oxides as coatings for orthopedic metallic implants

    Energy Technology Data Exchange (ETDEWEB)

    Pradhan, D.; Wren, A.W.; Misture, S.T.; Mellott, N.P., E-mail: mellott@alfred.edu

    2016-01-01

    Applying sol gel based coatings to orthopedic metallic implant materials can significantly improve their properties and lifespan in vivo. For this work, niobium (Nb{sub 2}O{sub 5}) and titanium (TiO{sub 2}) oxides were prepared via solution processing in order to determine the effect of atomic arrangement (amorphous/crystalline) on bioactivity. Thermal evaluation on the synthesized materials identified an endotherm for Nb{sub 2}O{sub 5} at 75 °C with 40% weight loss below 400 °C, and minimal weight loss between 400 and 850 °C. Regarding TiO{sub 2} an endotherm was present at 92 °C with 25% weight loss below 400 °C, and 4% between 400 and 850 °C. Phase evolution was determined using High Temperature X-ray Diffraction (HT-XRD) where amorphous-Nb{sub 2}O{sub 5} (450 °C), hexagonal-Nb{sub 2}O{sub 5} (525 °C), orthorhombic-Nb{sub 2}O{sub 5} (650 °C), amorphous-TiO{sub 2} (275 °C) and tetragonal TiO{sub 2} (500 °C) structures were produced. Simulated body fluid (SBF) testing was conducted over 1, 7 and 30 days and resulted in positive chemical and morphological changes for crystalline Nb{sub 2}O{sub 5} (525 °C) and TiO{sub 2} (500 °C) after 30 days of incubation. Rod-like CaP deposits were observed on the surfaces using Scanning Electron Microscopy (FE-SEM) and Grazing Incidence-X-ray Diffraction (GI-XRD) shows that the deposits were X-ray amorphous. Cell viability was higher with the TiO{sub 2} (122%) samples when compared to the growing cell population while Nb{sub 2}O{sub 5} samples exhibited a range of viability (64–105%), partially dependent on materials atomic structure. - Highlights: • Niobium and titanium oxides were prepared to determine the effect of structure on bioactivity. • Simulated body fluid testing resulted in positive surface chemical and morphological changes. • Amorphous, rod-like CaP deposits were observed on the surfaces. • Niobium oxide exhibited a range of viability partially dependent on materials atomic structure.

  4. Microscopic observations of osteoblast growth on micro-arc oxidized β titanium

    Science.gov (United States)

    Chen, Hsien-Te; Chung, Chi-Jen; Yang, Tsai-Ching; Tang, Chin-Hsin; He, Ju-Liang

    2013-02-01

    Titanium alloys are widely used in orthopedic and dental implants, owing to their excellent physical properties and biocompatibility. By using the micro-arc oxidation (MAO), we generated anatase-rich (A-TiO2) and rutile-rich (R-TiO2) titanium dioxide coatings, individually on β-Ti alloy, in which the latter achieved an enhanced in vitro and in vivo performance. Thoroughly elucidating how the osteoblasts interact with TiO2 coatings is of worthwhile interest. This study adopts the focused ion beam (FIB) to section off the TiO2 coated samples for further scanning electron microscope (SEM) and transmission electron microscope (TEM) observation. The detailed crystal structures of the TiO2 coated specimens are also characterized. Experimental results indicate osteoblasts adhered more tenaciously and grew conformably with more lamellipodia extent on the R-TiO2 specimen than on the A-TiO2 and raw β-Ti specimens. FIB/SEM cross-sectional images of the cell/TiO2 interface revealed micro gaps between the cell membrane and contact surface of A-TiO2 specimen, while it was not found on the R-TiO2 specimen. Additionally, the number of adhered and proliferated cells on the R-TiO2 specimen was visually greater than the others. Closely examining EDS line scans and elemental mappings of the FIB/TEM cross-sectional images of the cell/TiO2 interface reveals both the cell body and interior space of the TiO2 coating contain nitrogen and sulfur (the biological elements in cell). This finding supports the assumption that osteoblast can grow into the porous structure of TiO2 coatings and demonstrating that the R-TiO2 coating formed by MAO serves the best for β-Ti alloys as orthopedic and dental implants.

  5. Synthesis and characterization of titanium oxide/bismuth sulfide nanorods for solar cells applications

    International Nuclear Information System (INIS)

    Solis, M.; Rincon, M. E.

    2008-01-01

    In the present work is showed the synthesis and characterization of titanium oxide/bismuth sulfide nanowires hetero-junctions for solar cells applications. Conductive glass substrates (Corning 25 x 75 mm) were coated with a thin layer of sol-gel TiO2 and used as substrates for the subsequent deposition of bismuth sulfide nanorods (BN). TiO2 films (∼400 nm) were deposited with a semiautomatic immersion system with controlled immersion/withdraw velocity, using titanium isopropoxide as the titania precursor [1]. For BN synthesis and deposition, the solvo-thermal method was used, introducing air annealed TiO2-substrates in the autoclave. The typical bilayer TiO2/BN hetero-junction was 600 nm thick. The synthesized materials (powders and films) were characterized by X-Ray Diffraction, Scanning Electron Microscopy, and UV-Visible Spectroscopy. Anatase was the crystalline phase of TiO2, while bismuth sulfide nanotubes show a diffraction pattern characteristic of bismuthinite distorted by the preferential growth of some planes [2-4]. The optoelectronic characterization of TiO2/NB hetero-junctions was compared with hetero-junctions obtained by sensitizing TiO2 with chemically deposited bismuth sulfide films. Bismuth sulfide nanowires are 2µm long and 70nm wide (aspect ratio L/D = 43), while chemically deposited bismuth sulfide have L/D = 1, therefore the effect of particle size evaluation and geometry in the photosensitization phenomena will be discussed in the context of new materials for solar-cells applications. (Full text)

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

    Science.gov (United States)

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

    2015-02-01

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

  7. Recent Developments in Suspension Plasma Sprayed Titanium Oxide and Hydroxyapatite Coatings

    Science.gov (United States)

    Jaworski, R.; Pawlowski, L.; Pierlot, C.; Roudet, F.; Kozerski, S.; Petit, F.

    2010-01-01

    The paper aims at reviewing of the recent studies related to the development of suspension plasma sprayed TiO2 and Ca5(PO4)3OH (hydroxyapatite, HA) coatings as well as their multilayer composites obtained onto stainless steel, titanium and aluminum substrates. The total thickness of the coatings was in the range 10 to 150 μm. The suspensions on the base of distilled water, ethanol and their mixtures were formulated with the use of fine commercial TiO2 pigment crystallized as rutile and HA milled from commercial spray-dried powder or synthesized from calcium nitrate and ammonium phosphate in an optimized reaction. The powder was crystallized as hydroxyapatite. Pneumatic and peristaltic pump liquid feeders were applied. The injection of suspension to the plasma jet was studied carefully with the use of an atomizer injector or a continuous stream one. The injectors were placed outside or inside of the anode-nozzle of the SG-100 plasma torch. The stream of liquid was tested under angle right or slightly backwards with regard to the torch axis. The sprayed deposits were submitted to the phase analysis by the use of x-ray diffraction. The content of anatase and rutile was calculated in the titanium oxide deposits as well as the content of the decomposition phases in the hydroxyapatite ones. The micro-Raman spectroscopy was used to visualize the area of appearance of some phases. Scratch test enabled to characterize the adhesion of the deposits, their microhardness and friction coefficient. The electric properties including electron emission, impedance spectroscopy, and dielectric properties of some coatings were equally tested.

  8. Nano- and Micro-Scale Oxidative Patterning of Titanium Implant Surfaces for Improved Surface Wettability.

    Science.gov (United States)

    Kim, In-hye; Son, Jun Sik; Choi, Seok Hwa; Kim, Kyo-han; Kwon, Tae-yub

    2016-02-01

    A simple and scalable surface modification treatment is demonstrated, in which nano- and microscale features are introduced into the surface of titanium (Ti) substrates by means of a novel and eco-friendly oxidative aqueous solution composed of hydrogen peroxide (H202) and sodium bicarbonate (NaHCO3). By immersing mirror-polished Ti discs in an aqueous mixture of 30 wt% H2O2/5 wt% NaHCO3 at 23 +/- 3 degrees C for 4 h, it was confirmed that this mixture is capable of generating microscale topographies on Ti surfaces. It also simultaneously formed nanochannels that were regularly arranged in a comb-like pattern on the Ti surface, thus forming a hierarchical surface structure. Further, these nano/micro-textured Ti surfaces showed great surface roughness and excellent wettability when compared with control Ti surfaces. This study demonstrates that a H2O2/NaHCO3 mixture can be effectively utilized to create reproducible nano/microscale topographies on Ti implant surfaces, thus providing an economical new oxidative solution that may be used effectively and safely as a Ti surface modification treatment.

  9. Method of depositing thin films of high temperature Bi-Sr-Ca-Cu-O-based ceramic oxide superconductors

    International Nuclear Information System (INIS)

    Budd, K.D.

    1991-01-01

    This patent describes a method. It comprises preparing a liquid precursor of a Bi-Sr-Ca-Cu-O- based ceramic oxide superconductor phase, wherein the liquid precursor comprises an alkoxyalkanol, copper acrylate, strontium acrylate, bismuth nitrate, and calcium nitrate, wherein the liquid precursor has a cation ratio sufficient to form the desired stoichiometry in the ceramic oxide superconductor phase when the liquid precursor is heated to a temperature and for a time sufficient to provide the desired ceramic oxide superconductor phase, and wherein the copper acrylate, strontium acrylate, bismuth nitrate, and calcium nitrate are mutually soluble in the alkoxyalkanol; applying the liquid precursor to a substrate, wherein the substrate is one of an oxide ceramic, a metal selected from the group consisting of Ag and Ni, and Si; and heating the substrate in an oxygen-containing atmosphere with the liquid precursor applied thereon to a temperature and for a time sufficient to form a thin film comprising at least one Bi-Sr- Ca-Cu-O-based high temperature ceramic oxide superconductor phase

  10. Automated AC Electrical Impedance Measurement of Ceramic Oxides by means of a Lock-in Amplifier

    International Nuclear Information System (INIS)

    Al-Khawaja, S.; Al-Sous, M. B.; Nasrallah, F.

    2009-06-01

    In this study, the electrical impedance of some ceramic oxides has been investigated employing the Perkin Elmer DSP 7280 Lock-in amplifier, while recording the electric response versus frequency and temperature at constant amplitude. Via integral automation of this lock-in with other delicate electrical measuring devices, a control program has been developed to accurately and swiftly acquire the frequency response of the sample, in order to lately infer the resulting samples' impedance in volt and ampere. Two maxima peaks characterising the impedance, in the curve of the doped molybdenum oxide have been observed discerning two phases in the sample (doped with 40% of niobium oxide), which shows a remarkable relaxation related to improvement in its ionic conductivity within the solid phase, with respect to increasing frequency. (author)

  11. Oxidation of BN-coated SiC fibers in ceramic matrix composites

    International Nuclear Information System (INIS)

    Sheldon, B.W.; Sun, E.Y.

    1996-01-01

    Thermodynamic calculations were performed to analyze the simultaneous oxidation of BN and SiC. The results show that, with limited amounts of oxygen present, the formation of SiO 2 should occur prior to the formation of B 2 O 3 . This agrees with experimental observations of oxidation in glass-ceramic matrix composites with BN-coated SiC fibers, where a solid SiO 2 reaction product containing little or no boron has been observed. The thermodynamic calculations suggest that this will occur when the amount of oxygen available is restricted. One possible explanation for this behavior is that SiO 2 formation near the external surfaces of the composite closes off cracks or pores, such that vapor phase O 2 diffusion into the composite occurs only for a limited time. This indicates that BN-coated SiC fibers will not always oxidize to form significant amounts of a low-melting, borosilicate glass

  12. Oxide glass to high temperature ceramic superconductors - a novel route

    International Nuclear Information System (INIS)

    Chaudhuri, B.K.; Som, K.K.

    1992-01-01

    Recently it has been discovered that many of transition metal oxide (TMO) glasses like Bi-Sr-Ca-Cu-O, Y-Ba-Cu-O, Bi-Pb-Sr-Ca-Cu-O etc. can be directly converted to the corresponding high temperature superconducting phases by properly annealing the respective glasses. In this review recent developements in this field are summarised. The structural, electrical, dielectrical, magnetic, optical, and other properties of these new type of (TMO) glass systems have been elucidated comparing them with the corresponding results of already known (TMO) glasses which do not become superconductors on annealing above their glass transition temperatures (T g ). The electrical properties of this novel glass system have been analysed with reference to the various existing theoretical models based on polaron hopping conduction mechanism. The electrical, magnetic, and other properties of the respective superconductors obtained from their corresponding glass phases by annealing above (T g ) and the possibility of drawing wires, ribbons etc. from these glass matrices and then converting them to their high T c superconducting phases have also been discussed. (author). 107 refs., 32 figs., 5 tabs

  13. Platinized titanium dioxide electrodes for methanol oxidation and photo-oxidation

    Directory of Open Access Journals (Sweden)

    IOANNIS POULIOS

    2012-11-01

    Full Text Available Platinized deposits have been formed on TiO2 particulate films supported on Ti substrates, by means of galvanic replacement of pre-deposited metallic Cu and subsequent immersion of the Cu/TiO2 coatings into a chloroplatinic acid solution. The spontaneous replacement of Cu by Pt results in Pt(Cu/TiO2/Ti electrodes. Both the platinized and the precursor TiO2/Ti electrodes have been characterized by SEM micro­scopy/EDS spectroscopy, their surface electrochemistry has been assessed by cyclic voltammetry in the dark and their photoelectrochemical properties by photovolta­m­metry under UV illumination. It has been found that, although platinized rutile-rich electrodes exhibit typical Pt surface electrochemistry, the anatase-rich electrodes show only traces of oxide formation and stripping. The latter has been translated to a suppression of methanol oxidation at anatase-rich electrodes. On the contrary, methanol oxidation at platinized rutile-rich electrodes occurs at significant rates and can be further enhanced upon UV illumination, as a result of Pt and TiO2 synergism in the photoelectrochemical oxidation of methanol.

  14. Titanium Oxide/Platinum Catalysis: Charge Transfer from a Titanium Oxide Support Controls Activity and Selectivity in Methanol Oxidation on Platinum

    KAUST Repository

    Hervier, Antoine; Baker, L. Robert; Komvopoulos, Kyriakos; Somorjai, Gabor A.

    2011-01-01

    formaldehyde, methyl formate, and carbon dioxide. F-doped samples demonstrated significantly higher activity for methanol oxidation when the TiOx was stoichiometric (TiO 2), but lower activity when it was nonstoichiometric (TiO 1.7 and TiO1.9). These results

  15. Functional doped metal oxide films. Zinc oxide (ZnO) as transparent conducting oxide (TCO) titanium dioxide (TiO{sub 2}) as thermographic phosphor and protective coating

    Energy Technology Data Exchange (ETDEWEB)

    Nebatti Ech-Chergui, Abdelkader

    2011-07-29

    spectra indicate that the red characteristic emission of TiO{sub 2}: Eu{sup 3+} due to electric dipole {sup 5}D{sub 0} {yields}{sup 7} F{sub 2} transition occurring after ultraviolet excitation is the strongest. The decay time of the phosphorescence after UV excitation with a Nd:YAG laser (355 nm, f=10Hz) is temperature dependent in the range from 200 C up to 400 C. Finally, it has been found that the lifetime show a significant dependency on europium concentration. The development of rutile phase of titanium dioxide films on stainless steel substrates as protective coatings were investigated. Generally the rutile phases of TiO{sub 2} thin films do not adhere well on stainless steel substrates. In order to improve the adhesion, stainless steel substrates were first coated with titanium films using cathodic vacuum arc deposition. Then these titanium coatings were partially transformed to the rutile phase of titanium dioxide by thermal oxidation. The presence of the rutile phase of titanium dioxide and metallic titanium were confirmed by XRD. Cavitation erosion was used for the first time to investigate the adhesion properties of these coatings. Cavitation erosion tests confirmed that rutile films with a Ti inter layer are well adherent to stainless steel substrates and protect the substrate from erosion. The total mass loss of the thermally oxidized samples of Ti coated stainless steel was found around 3.5 times lower than of the uncoated samples. (orig.)

  16. The influence of adding modified zirconium oxide-titanium dioxide nano-particles on mechanical properties of orthodontic adhesive: an in vitro study

    OpenAIRE

    Felemban, Nayef H.; Ebrahim, Mohamed I.

    2017-01-01

    Background The purpose of this in-vitro study was to examine the effect of incorporating different concentrations of Zirconium oxide-Titanium dioxide (ZrO2-TiO2) nanoparticles, which can have antibacterial properties, on the mechanical properties of an orthodontic adhesive. Methods ZrO2-TiO2 (Zirconium oxide, HWNANO, Hongwu International Group Ltd, China) -Titanium dioxide, Nanoshell, USA) nanopowder were incorporated into orthodontic adhesive (Transbond XT, 3?M Unitek, Monrovia, USA) with di...

  17. Spectroscopy study of ceramic pigments based on Ce(IV)-Pr(IV) oxide

    International Nuclear Information System (INIS)

    Furtado, L.; Toma, H.E.

    1991-01-01

    The synthesis and spectroscopic properties of a series of cerium(IV)-praseodimium(IV) oxide pigments are reported. The pigments exhibit brick-red colours and are suitable for ceramic applications because of their high temperature stability. Electronic absorption spectra of the pigments suspended in a gel matrix of polyvinyl alcohol-sodium tetradecaborate mixture, consists of broad band with gaussian components at 372 and 472nm. These bands are described to charge -transfer transitions from the occupied oxygen p-orbitals to the empty f levels of the lanthanides. (author)

  18. A structural study of ceramic oxides by X-ray absorption spectroscopy

    International Nuclear Information System (INIS)

    Akhtar, M.J.

    1995-01-01

    A detailed structural study of ceramic oxides is presented by employing X-ray Absorption Spectroscopy (XAS). In the present work X-ray Absorption Near Edge Structure (XANES) is used for the investigation of valence state of metal cations; whereas, Extended X-ray Absorption Fine Structure EXAFS) is employed for the determination for bond lengths, coordination numbers and nature of the elements present in the near neighbour shells surrounding the absorbing atom. These results show that local environment of dopant and host cations are different; and this variation in local structure depends on the nature and concentration of the dopant ions. (author)

  19. Investigation of TLD properties of metal alloy oxides, glass, ceramics and various papers

    International Nuclear Information System (INIS)

    Erkol, A.Y.; Yasar, S.; Karakelle, B.; Yasar, D.

    1995-01-01

    A large number of materials exhibit radiothermoluminescence and they are extensively used for radiation process control. In this work, the thermoluminescence (TL) properties of metal alloy oxides, glass, ceramics and various papers are investigated in order to evaluate their possible usage as TL detectors or indicators in dose measurement. TL glow curves and the effect of absorbed dose on TL response are measured for materials locally available. The fading effect are also examined. The use of these materials as a dose indicator are shown to be promising. (author)

  20. Investigation of TLD properties of metal alloy oxides, glass, ceramics and various papers

    International Nuclear Information System (INIS)

    Erkol, A.Y.; Yasar, S.; Karakelle, B.; Yasar, D.

    1995-01-01

    A large number of materials exhibit radiothermoluminescence and they are extensively used for radiation process control. In this work, the thermoluminescence (TL) properties of metal alloy oxides, glass, ceramics and various papers are investigated in order to evaluate their possible usage as TL detectors or indicators in dose measurement. TL glow curves and the effect of absorbed dose on TL response are measured for materials locally available. The fading effect is also examined. The use of these materials as a dose indicator is shown to be promising. (author)

  1. Radiation effects in cubic zirconia: A model system for ceramic oxides

    Science.gov (United States)

    Thomé, L.; Moll, S.; Sattonnay, G.; Vincent, L.; Garrido, F.; Jagielski, J.

    2009-06-01

    Ceramics are key engineering materials for electronic, space and nuclear industry. Some of them are promising matrices for the immobilization and/or transmutation of radioactive waste. Cubic zirconia is a model system for the study of radiation effects in ceramic oxides. Ion beams are very efficient tools for the simulation of the radiations produced in nuclear reactors or in storage form. In this article, we summarize the work made by combining advanced techniques (RBS/C, XRD, TEM, AFM) to study the structural modifications produced in ion-irradiated cubic zirconia single crystals. Ions with energies in the MeV-GeV range allow exploring the nuclear collision and electronic excitation regimes. At low energy, where ballistic effects dominate, the damage exhibits a peak around the ion projected range; it accumulates with a double-step process by the formation of a dislocation network. At high energy, where electronic excitations are favored, the damage profiles are rather flat up to several micrometers; the damage accumulation is monotonous (one step) and occurs through the creation and overlap of ion tracks. These results may be generalized to many nuclear ceramics.

  2. Analog memory and spike-timing-dependent plasticity characteristics of a nanoscale titanium oxide bilayer resistive switching device

    International Nuclear Information System (INIS)

    Seo, Kyungah; Park, Sangsu; Lee, Kwanghee; Lee, Byounghun; Hwang, Hyunsang; Kim, Insung; Jung, Seungjae; Jo, Minseok; Park, Jubong; Shin, Jungho; Biju, Kuyyadi P; Kong, Jaemin

    2011-01-01

    We demonstrated analog memory, synaptic plasticity, and a spike-timing-dependent plasticity (STDP) function with a nanoscale titanium oxide bilayer resistive switching device with a simple fabrication process and good yield uniformity. We confirmed the multilevel conductance and analog memory characteristics as well as the uniformity and separated states for the accuracy of conductance change. Finally, STDP and a biological triple model were analyzed to demonstrate the potential of titanium oxide bilayer resistive switching device as synapses in neuromorphic devices. By developing a simple resistive switching device that can emulate a synaptic function, the unique characteristics of synapses in the brain, e.g. combined memory and computing in one synapse and adaptation to the outside environment, were successfully demonstrated in a solid state device.

  3. Simple solution-processed titanium oxide electron transport layer for efficient inverted polymer solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Liang [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Shen, Wenfei [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Institute of Hybrid Materials, Laboratory of New Fiber Materials and Modern Textile—The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Chen, Weichao [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Bao, Xichang, E-mail: baoxc@qibebt.ac.cn [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Wang, Ning; Dou, Xiaowei; Han, Liangliang; Wen, Shuguang [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China)

    2014-12-31

    Titanium oxide (TiO{sub X}) is an effective electron transport layer (ETL) in polymer solar cells (PSCs). We report efficient inverted PSCs with a simple solution-processed amorphous TiO{sub X} (s-TiO{sub X}) film as an ETL. The s-TiO{sub X} film with high light transmittance was prepared by spin-coating titanium (IV) isopropoxide isopropanol solution on indium tin oxide coated glass in inert and then placed in air under room temperature for 60 min. The introduction of s-TiO{sub X} ETL greatly improved the short circuit current density of the devices. PSCs based on poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester and poly(4,8-bis-alkyloxy-benzo[1,2-b:4,5-b′]dithiophene-alt-alkylcarbonyl -thieno[3,4-b]thiophene):[6,6]-phenyl- C71-butyric acid methyl ester using s-TiO{sub X} film as ETL shows high power conversion efficiency of 4.29% and 6.7% under the illumination of AM 1.5G, 100 mW/cm{sup 2}, which shows enhancements compared to the conventional PSCs with poly(styrenesulfonate)-doped poly(ethylenedioxythiophene) as anode buffer layer. In addition, the device exhibits good stability in a humid ambient atmosphere without capsulation. The results indicate that the annealing-free, simple solution processed s-TiO{sub X} film is an efficient ETL for high-performance PSCs. - Highlights: • High quality s-TiO{sub X} films were prepared by a simple, solution method without thermal treatment. • The s-TiO{sub X} films with high transmittance are very smooth. • The organic photovoltaic performance with s-TiO{sub X} film improved greatly and exhibited good stability. • The annealing-free, simple prepared s-TiO{sub X} film will be much compatible with flexible substrates.

  4. Formation of titanium oxide coatings on NiTi shape memory alloys by selective oxidation

    International Nuclear Information System (INIS)

    Pohl, M.; Glogowski, T.; Kuehn, S.; Hessing, C.; Unterumsberger, F.

    2008-01-01

    Materials used for medical devices that are in contact with human tissue must have good corrosion resistance and biocompatibility. NiTi shape memory alloys (SMAs) are often used in medical applications due to their special functional and mechanical properties (shape memory effect, pseudo elasticity). Because of the high Ni content in nearly stoichiometric NiTi SMAs, the possibility of Ni being released needs to be considered as Ni may cause problems in the human body. SMAs exhibit a high intrinsic corrosion resistance because of the thermodynamic stability of Ni (thermodynamic reason) and the low degree of disorder in a thin protective TiO 2 -layer (kinetic reason). While therefore there is no need to be concerned too much about a normal corrosive attack in the human body, it has to be kept in mind that in medical applications, these materials represent one part of a tribological system where wear processes need to be considered. The formation of a uniform TiO 2 -layer can be beneficial in this respect. The selective oxidation of Ti to TiO 2 on the surface is a promising method to decrease the Ni release significantly. This can be achieved by controlling the partial pressure of oxygen during a controlled oxidation process. The atmosphere must be adjusted so that TiO 2 is stable while NiO cannot yet form. The result of a selective oxidation is a TiO 2 -layer that has an excellent degree of purity and represents a safe barrier against Ni emission

  5. Aqueous arsenite removal by simultaneous ultraviolet photocatalytic oxidation-coagulation of titanium sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yuxia [Key Laboratory of Northwest Water Resources, Environment and Ecology, MOE, School of Environmental & Municipal Engineering, Xi’an University of Architecture and Technology (China); Duan, Jinming, E-mail: jinmingduan@xauat.edu.cn [Key Laboratory of Northwest Water Resources, Environment and Ecology, MOE, School of Environmental & Municipal Engineering, Xi’an University of Architecture and Technology (China); Centre for Water Management and Reuse, School of Natural and Built Environments, University of South Australia, Mawson Lakes Campus, South Australia (Australia); Li, Wei [Key Laboratory of Northwest Water Resources, Environment and Ecology, MOE, School of Environmental & Municipal Engineering, Xi’an University of Architecture and Technology (China); Beecham, Simon; Mulcahy, Dennis [Centre for Water Management and Reuse, School of Natural and Built Environments, University of South Australia, Mawson Lakes Campus, South Australia (Australia)

    2016-02-13

    Highlights: • A simultaneous UV catalysed oxidation–coagulation for As(III) removal is proposed. • As(III) was effectively oxidised to As(V) by the UV catalysed coagulation. • >99% removal for As(III) in pH 4–6 at low doses of Ti(SO{sub 4}){sub 2} was achieved. • Concurrent UV radiation in massive small crystal formation facilitate the effects. • Reaction mechanisms involve both hydroxyl radicals and superoxide radicals. - Abstract: This study explored the efficacy and efficiency of a simultaneous UV-catalyzed oxidation–coagulation process of titanium sulfate (UV/Ti(SO{sub 4}){sub 2}) for efficient removal of As(III) from water. It revealed that, As(III) could be oxidized to As(V) during the UV catalyzed coagulation of Ti(SO{sub 4}){sub 2} with highly efficient As(III) removal in the pH range 4–6{sub .} The UV catalyzed oxidation–coagulation showed surprisingly effective oxidation of As(III) to As(V) within a short time. XPS indicated that 84.7% of arsenic on the coagulated precipitate was in the oxidized form of As(V) after the UV/Ti(SO{sub 4}){sub 2} treatment of As(III) aqueous solutions at pH 5. Arsenic remaining in solution at high pH was in the oxidized form As(V). Removal efficiencies of As(III) were investigated as a function of pH, Ti(SO{sub 4}){sub 2} dosage, initial As(III) concentration and irradiation energy. As(III) could almost completely be removed (>99%) by the photocatalytic oxidation–coagulation process with a moderate dose of Ti(SO{sub 4}){sub 2} in the pH range 4–6 at an initial arsenic concentration of 200 μg/L. The mechanisms of the photocatalytic coagulation oxidation of Ti(SO{sub 4}){sub 2} are similar to those of UV/crystalline TiO{sub 2} particles, involving the formation and reactions of the hydroxyl radical OH· and superoxide HO{sub 2}·/O{sub 2}{sup ·−}.

  6. Reactive Spark Plasma Sintering and Mechanical Properties of Zirconium Diboride–Titanium Diboride Ultrahigh Temperature Ceramic Solid Solutions

    Directory of Open Access Journals (Sweden)

    Karthiselva N. S.

    2016-09-01

    Full Text Available Ultrahigh temperature ceramics (UHTCs such as diborides of zirconium, hafnium tantalum and their composites are considered to be the candidate materials for thermal protection systems of hypersonic vehicles due to their exceptional combination of physical, chemical and mechanical properties. A composite of ZrB2-TiB2 is expected to have better properties. In this study, an attempt has been made to fabricate ZrB2-TiB2 ceramics using mechanically activated elemental powders followed by reactive spark plasma sintering (RSPS at 1400 °C. Microstructure and phase analysis was carried out using X-ray diffractometer (XRD and electron microscopy to understand microstructure evolution. Fracture toughness and hardness were evaluated using indentation methods. Nanoindentation was used to measure elastic modulus. Compressive strength of the composites has been reported.

  7. Titanium oxide modification with oxides of mixed cobalt valence for photo catalysis

    International Nuclear Information System (INIS)

    Alanis O, R.; Jimenez B, J.

    2010-01-01

    In the present work, heterogenous photo catalysis, a technique often used for organic compound degradation toxic in water, was used. The photo catalyst most often used in this technique is TiO 2 , which due to its physical and chemical properties, can degrade a great number of organic compounds. In addition, in recent years it has been verified that the doping of semiconductors with metals or metallic oxides increases the photo catalytic activity of these semiconductors, which is why it was proposed for doping by the impregnating method using commercial TiO 2 synthesized by the Degussa company (TiO 2 Degussa P25) with and oxide of mixed cobalt valence (Co 3 O 4 ) synthesized using the sol-gel method. The synthesized photo catalyst TiO 2 /Co 3 O 4 was characterized by the techniques of X-ray diffraction, scanning electronic microscopy, Raman spectroscopy and finally, photo catalytic tests by means of the degradation of methylene blue. (Author)

  8. Titanium oxide modification with oxides of mixed cobalt valence for photo catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Alanis O, R.; Jimenez B, J., E-mail: jaime.jimenez@inin.gob.m [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2010-07-01

    In the present work, heterogenous photo catalysis, a technique often used for organic compound degradation toxic in water, was used. The photo catalyst most often used in this technique is TiO{sub 2}, which due to its physical and chemical properties, can degrade a great number of organic compounds. In addition, in recent years it has been verified that the doping of semiconductors with metals or metallic oxides increases the photo catalytic activity of these semiconductors, which is why it was proposed for doping by the impregnating method using commercial TiO{sub 2} synthesized by the Degussa company (TiO{sub 2} Degussa P25) with and oxide of mixed cobalt valence (Co{sub 3}O{sub 4}) synthesized using the sol-gel method. The synthesized photo catalyst TiO{sub 2}/Co{sub 3}O{sub 4} was characterized by the techniques of X-ray diffraction, scanning electronic microscopy, Raman spectroscopy and finally, photo catalytic tests by means of the degradation of methylene blue. (Author)

  9. Synthesis, characterization and photo catalytic activity of titanium oxide modified with nitrogen; Sintesis, caracterizacion y actividad fotocatalitica de oxido de titanio modificado con nitrogeno

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Enriquez, J. M.; Garcia Alamilla, R.; Garcia Serrano, L. A.; Cueto Hernandez, A.

    2011-07-01

    Titanium oxides (TiO{sub 2}) were synthesized by precipitation of titanium tetrachloride (TiCl{sub 4}) using ammonium hydroxide (NH{sub 4}OH). The synthesized materials were characterized by means of nitrogen physisorption, X-ray diffraction, infrared spectroscopy, U.V.-visible diffuse reflectance spectroscopy and the photo catalytic activity of the samples were measured by the degradation of the methyl orange. By means of this synthesis method we have doped the titanium oxide structure with nitrogen (N-TiO{sub 2}), stabilizing the anatase phase and obtaining meso porous and nanocrystalline materials. The titanium oxide with higher specific surface area (132 m{sup 2}/g) degraded the azo-compound to 100% in 180 min of reaction. (Author) 33 refs.

  10. Superior biocompatibility and osteogenic efficacy of micro-arc oxidation-treated titanium implants in the canine mandible

    International Nuclear Information System (INIS)

    Ran Wei; Guo Bing; Shu Dalong; Tian Zhihui; Nan Kaihui; Wang Yingjun

    2009-01-01

    The aim of this paper is to test implantation outcomes and osteogenic efficacy of plasma micro-arc oxidation (MAO)-treated titanium implants in dogs. Thirty-six pure titanium implants (18 MAO-treated, 18 untreated) were inserted into the mandibles of nine adult beagles and allowed to heal under non-weight-bearing conditions. Implant stability and interface characteristics were evaluated at 4, 8 and 12 weeks post-implantation. Methods included scanning electron microscopy, mechanical testing, histological analysis and computer-quantified tissue morphology. Osseointegration was achieved in both groups, but occurred earlier and more extensively in the MAO group. Areas of direct bone/implant contact were approximately nine times higher in the MAO group than in the control group at 12 weeks (65.85% versus 7.37%, respectively; p < 0.01). Bone-implant shear strength in the MAO group (71.4, 147.2 and 266.3 MPa at weeks 4, 8 and 12, respectively) was higher than in the control group (4.3, 7.1, and 11.8 MPa at weeks 4, 8 and 12, respectively), at all assessments (all, p < 0.01). MAO treatment of titanium implants promotes more rapid formation of new bone, and increases bone-implant shear strength compared to untreated titanium implants.

  11. Titanium(IV), zirconium, hafnium and thorium

    International Nuclear Information System (INIS)

    Brown, Paul L.; Ekberg, Christian

    2016-01-01

    Titanium can exist in solution in a number of oxidation states. The titanium(IV) exists in acidic solutions as the oxo-cation, TiO 2+ , rather than Ti 4+ . Zirconium is used in the ceramics industry and in nuclear industry as a cladding material in reactors where its reactivity towards hydrolysis reactions and precipitation of oxides may result in degradation of the cladding. In nature, hafnium is found together with zirconium and as a consequence of the contraction in ionic radii that occurs due to the 4f -electron shell, the ionic radius of hafnium is almost identical to that of zirconium. All isotopes of thorium are radioactive and, as a consequence of it being fertile, thorium is important in the nuclear fuel cycle. The polymeric hydrolysis species that have been reported for thorium are somewhat different to those identified for zirconium and hafnium, although thorium does form the Th 4 (OH) 8 8+ species.

  12. Imitation of phase I oxidative metabolism of anabolic steroids by titanium dioxide photocatalysis.

    Science.gov (United States)

    Ruokolainen, Miina; Valkonen, Minna; Sikanen, Tiina; Kotiaho, Tapio; Kostiainen, Risto

    2014-12-18

    The aim of this study was to investigate the feasibility of titanium dioxide (TiO2) photocatalysis for oxidation of anabolic steroids and for imitation of their phase I metabolism. The photocatalytic reaction products of five anabolic steroids were compared to their phase I in vitro metabolites produced by human liver microsomes (HLM). The same main reaction types - hydroxylation, dehydrogenation and combination of these two - were observed both in TiO2 photocatalysis and in microsomal incubations. Several isomers of each product type were formed in both systems. Based on the same mass, retention time and similarity of the product ion spectra, many of the products observed in HLM reactions were also formed in TiO2 photocatalytic reactions. However, products characteristic to only either one of the systems were also formed. In conclusion, TiO2 photocatalysis is a rapid, simple and inexpensive method for imitation of phase I metabolism of anabolic steroids and production of metabolite standards. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. pH-regulated antimony oxychloride nanoparticle formation on titanium oxide nanostructures: a photocatalytically active heterojunction

    KAUST Repository

    Buchholcz, Balázs

    2017-02-06

    Improving the catalytic activity of heterogeneous photocatalysts has become a hot topic recently. To this end, considerable progress has been made in the efficient separation of photogenerated charge carriers by e.g. the realization of heterojunction photocatalysts. V-VI-VII compound semiconductors, namely, bismuth oxyhalides, are popular photocatalysts. However, results on antimony oxyhalides [SbOX (X = Br, Cl, I)], the very promising alternatives to the well-known BiOX photomodifiers, are scarce. Here, we report the successful decoration of titanium oxide nanostructures with 8-11 nm diameter SbOX nanoparticles for the first time ever. The product size and stoichiometry could be controlled by the pH of the reactant mixture, while subsequent calcination could transform the structure of the titanate nanotube (TiONT) support and the prepared antimony oxychloride particles. In contrast to the ease of composite formation in the SbOX/TiONT case, anatase TiO could not facilitate the formation of antimony oxychloride nanoparticles on its surface. The titanate nanotube-based composites showed activity in a generally accepted quasi-standard photocatalytic test reaction (methyl orange dye decolorization). We found that the SbOCl/TiONT synthesized at pH = 1 is the most active sample in a broad temperature range.

  14. Nanoparticles of Titanium and Zinc Oxides as Novel Agents in Tumor Treatment: a Review

    Science.gov (United States)

    Bogdan, Janusz; Pławińska-Czarnak, Joanna; Zarzyńska, Joanna

    2017-03-01

    Cancer has become a global problem. On all continents, a great number of people are diagnosed with this disease. In spite of the progress in medical care, cancer still ends fatal for a great number of the ill, either as a result of a late diagnosis or due to inefficiency of therapies. The majority of the tumors are resistant to drugs. Thus, the search for new, more effective therapy methods continues. Recently, nanotechnology has been attributed with big expectations in respect of the cancer fight. That interdisciplinary field of science creates nanomaterials (NMs) and nanoparticles (NPs) that can be applied, e.g., in nanomedicine. NMs and NPs are perceived as very promising in cancer therapy since they can perform as drug carriers, as well as photo- or sonosensitizers (compounds that generate the formation of reactive oxygen species as a result of either electromagnetic radiation excitation with an adequate wavelength or ultrasound activation, respectively). Consequently, two new treatment modalities, the photodynamic therapy (PDT) and the sonodynamic therapy (SDT) have been created. The attachment of ligands or antibodies to NMs or to NPs improve their selective distribution into the targeted organ or cell; hence, the therapy effectiveness can be improved. An important advantage of the targeted tumor treatment is lowering the cyto- and genotoxicity of active substance towards healthy cells. Therefore, both PDT and SDT constitute a valuable alternative to chemo- or radiotherapy. The vital role in cancer eradication is attributed to two inorganic sensitizers in their nanosized scale: titanium dioxide and zinc oxide.

  15. Synthesis and characterization of Tin / Titanium mixed oxide nanoparticles doped with lanthanide for biomarking

    International Nuclear Information System (INIS)

    Paganini, Paula Pinheiro

    2012-01-01

    This work presents the synthesis, characterization and photo luminescent study of tin and titanium mixed oxide nanoparticles doped with europium, terbium and neodymium to be used with luminescent markers on biological systems. The syntheses were done by co-precipitation, protein sol-gel and Pechini methods and the nanoparticles were characterized by infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, X-ray diffraction and X-ray absorption spectroscopy. The photo luminescent properties studies were conducted for luminophores doped with europium, terbium and neodymium synthesized by coprecipitation method. For luminophore doped with europium it was possible to calculate the intensity parameters and quantum yield and it showed satisfactory results. In the case of biological system marking it was necessary the functionalization of these particles to allow them to bind to the biological part to be studied. So the nanoparticles were functionalized by microwave and Stöber methods and characterized by infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction obtaining qualitative response of functionalization efficacy. The ninhydrin spectroscopic method was used for quantification of luminophores functionalization. The photo luminescent studies of functionalized particles demonstrate the potential applying of these luminophores as luminescent markers. (author)

  16. Cycle Life of Commercial Lithium-Ion Batteries with Lithium Titanium Oxide Anodes in Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Xuebing Han

    2014-07-01

    Full Text Available The lithium titanium oxide (LTO anode is widely accepted as one of the best anodes for the future lithium ion batteries in electric vehicles (EVs, especially since its cycle life is very long. In this paper, three different commercial LTO cells from different manufacturers were studied in accelerated cycle life tests and their capacity fades were compared. The result indicates that under 55 °C, the LTO battery still shows a high capacity fade rate. The battery aging processes of all the commercial LTO cells clearly include two stages. Using the incremental capacity (IC analysis, it could be judged that in the first stage, the battery capacity decreases mainly due to the loss of anode material and the degradation rate is lower. In the second stage, the battery capacity decreases much faster, mainly due to the degradation of the cathode material. The result is important for the state of health (SOH estimation and remaining useful life (RUL prediction of battery management system (BMS for LTO batteries in EVs.

  17. Effect of silver on the phase transition and wettability of titanium oxide films

    Science.gov (United States)

    Mosquera, Adolfo A.; Albella, Jose M.; Navarro, Violeta; Bhattacharyya, Debabrata; Endrino, Jose L.

    2016-01-01

    The effect of silver on the phase transition and microstructure of titanium oxide films grown by pulsed cathodic arc had been investigated by XRD, SEM and Raman spectroscopy. Following successive thermal annealing up to 1000 °C, microstructural analysis of annealed Ag-TiO2 films reveals that the incorporation of Ag nanoparticles strongly affects the transition temperature from the initial metastable amorphous phase to anatase and stable rutile phase. An increase of silver content into TiO2 matrix inhibits the amorphous to anatase phase transition, raising its temperature boundary and, simultaneously reduces the transition temperature to promote rutile structure at lower value of 600 °C. The results are interpreted in terms of the steric effects produced by agglomeration of Ag atoms into larger clusters following annealing which hinders diffusion of Ti and O ions for anatase formation and constrains the volume available for the anatase lattice, thus disrupting its structure to form rutile phase. The effect of silver on the optical and wetting properties of TiO2 was evaluated to demonstrate its improved photocatalytic performance. PMID:27571937

  18. Characteristics of titanium oxide memristor with coexistence of dopant drift and a tunnel barrier

    International Nuclear Information System (INIS)

    Tian Xiao-Bo; Xu Hui

    2014-01-01

    The recent published experimental data of titanium oxide memristor devices which are tested under the same experimental conditions exhibit the strange instability and complexity of these devices. Such undesired characteristics preclude the understanding of the device conductive processes and the memristor-based practical applications. The possibility of the coexistence of dopant drift and tunnel barrier conduction in a memristor provides preliminary explanations for the undesired characteristics. However, current research lacks detailed discussion about the coexistence case. In this paper, dopant drift and tunnel barrier-based theories are first analyzed for studying the relations between parameters and physical variables which affect characteristics of memristors, and then the influences of each parameter change on the conductive behaviors in the single and coexistence cases of the two mechanisms are simulated and discussed respectively. The simulation results provide further explanations of the complex device conduction. Theoretical methods of eliminating or reducing the coexistence of the two mechanisms are proposed, in order to increase the stability of the device conduction. This work also provides the support for optimizing the fabrications of memristor devices with excellent performance

  19. Kinetics of the homogeneous exchange of alpha-lactalbumin adsorbed on titanium oxide surface.

    Science.gov (United States)

    Bentaleb, A; Haïkel, Y; Voegel, J C; Schaaf, P

    1998-06-05

    The homogeneous exchange process whereby alpha-lactalbumine molecules adsorbed on hydrophilic titanium oxide particles are replaced by alpha-lactalbumine molecules in solution has been investigated by means of a 125I radio-labeling technique, alpha-lactalbumine is a compact and highly negatively charged protein, making this study complementary to previous work devoted to the general understanding of the exchange mechanisms of adsorbed proteins on solid surfaces. The isotherm of alpha-lactalbumine exhibits bimodal adsorption shape, and the exchange process whereby adsorbed proteins are replaced by new incoming ones from the bulk solution has been studied at both the upper and the lower plateau of the isotherm. In the upper plateau the exchange process was found to be of first order with respect to the bulk molecules, and the release rate constant was equal to 0.914 L. mol-1.s-1. This behavior is identical to what has been observed with other proteinic systems. In the lower plateau domain, in contrast, the protein release process is independent of the concentration of proteins in the bulk, but the release rates are higher than the pure desorption rates. This constitutes, to our knowledge, a behavior that never before has been observed and that remains to be explained.

  20. Transmission Electron Microscopy Studies of Electron-Selective Titanium Oxide Contacts in Silicon Solar Cells

    KAUST Repository

    Ali, Haider

    2017-08-15

    In this study, the cross-section of electron-selective titanium oxide (TiO2) contacts for n-type crystalline silicon solar cells were investigated by transmission electron microscopy. It was revealed that the excellent cell efficiency of 21.6% obtained on n-type cells, featuring SiO2/TiO2/Al rear contacts and after forming gas annealing (FGA) at 350°C, is due to strong surface passivation of SiO2/TiO2 stack as well as low contact resistivity at the Si/SiO2/TiO2 heterojunction. This can be attributed to the transformation of amorphous TiO2 to a conducting TiO2-x phase. Conversely, the low efficiency (9.8%) obtained on cells featuring an a-Si:H/TiO2/Al rear contact is due to severe degradation of passivation of the a-Si:H upon FGA.

  1. Photocatalysis of zinc oxide nanotip array/titanium oxide film heterojunction prepared by aqueous solution deposition

    Science.gov (United States)

    Lee, Ming-Kwei; Lee, Bo-Wei; Kao, Chen-Yu

    2017-05-01

    A TiO2 film was prepared on indium tin oxide (ITO)/glass by aqueous solution deposition (ASD) with precursors of ammonium hexafluoro-titanate and boric acid at 40 °C. The photocatalysis of annealed TiO2 film increases with increasing growth time and decreases with increasing growth times longer than 60 min. A ZnO nanotip array was prepared on ZnO seed layer/TiO2 film/glass by aqueous solution deposition with precursors of zinc nitrate and ammonium hydroxide at 70 °C. The photocatalysis of ASD-ZnO/ASD-TiO2 film/ITO glass can be better than that of P25.

  2. Preparation of porous titanium oxide films onto indium tin oxide for application in organic photovoltaic devices

    Energy Technology Data Exchange (ETDEWEB)

    Macedo, Andreia G. [Laboratorio de Dispositivos Nanoestruturados, Departamento de Fisica, Universidade Federal do Parana, Curitiba, Parana (Brazil); Mattos, Luana L.; Spada, Edna R.; Serpa, Rafael B.; Campos, Cristiani S. [Laboratorio de Sistemas Nanoestruturados, Departamento de Fisica, Universidade Federal de Santa Catarina, Florianopolis, Santa Catarina (Brazil); Grova, Isabel R.; Ackcelrud, Leni [Laboratorio de Polimeros Paulo Scarpa, Departamento de Quimica, Universidade Federal do Parana, Curitiba, Parana (Brazil); Reis, Francoise T.; Sartorelli, Maria L. [Laboratorio de Sistemas Nanoestruturados, Departamento de Fisica, Universidade Federal de Santa Catarina, Florianopolis, Santa Catarina (Brazil); Roman, Lucimara S., E-mail: lsroman@fisica.ufpr.br [Laboratorio de Dispositivos Nanoestruturados, Departamento de Fisica, Universidade Federal do Parana, Curitiba, Parana (Brazil)

    2012-05-01

    In this work, porous ordered TiO{sub 2} films were prepared through sol gel route by using a monolayer of polystyrene spheres as template on indium-tin oxide/glass substrate. These films were characterized by SEM, AFM, Raman spectroscopy, UV-vis absorbance and XRD. The UV-vis absorbance spectrum show a pseudo band gap (PBG) with maxima at 460 nm arising from the light scattering and partial or total suppression of the photon density of states, this PBG can be controlled by the size of the pore. We also propose the use of this porous film as electron acceptor electrode in organic photovoltaic cells; we show that devices prepared with porous titania displayed higher efficiencies than devices using compact titania films as electrode. Such behaviour was observed in both bilayer and bulk heterojunction devices.

  3. Preparation of porous titanium oxide films onto indium tin oxide for application in organic photovoltaic devices

    International Nuclear Information System (INIS)

    Macedo, Andreia G.; Mattos, Luana L.; Spada, Edna R.; Serpa, Rafael B.; Campos, Cristiani S.; Grova, Isabel R.; Ackcelrud, Leni; Reis, Françoise T.; Sartorelli, Maria L.; Roman, Lucimara S.

    2012-01-01

    In this work, porous ordered TiO 2 films were prepared through sol gel route by using a monolayer of polystyrene spheres as template on indium-tin oxide/glass substrate. These films were characterized by SEM, AFM, Raman spectroscopy, UV-vis absorbance and XRD. The UV-vis absorbance spectrum show a pseudo band gap (PBG) with maxima at 460 nm arising from the light scattering and partial or total suppression of the photon density of states, this PBG can be controlled by the size of the pore. We also propose the use of this porous film as electron acceptor electrode in organic photovoltaic cells; we show that devices prepared with porous titania displayed higher efficiencies than devices using compact titania films as electrode. Such behaviour was observed in both bilayer and bulk heterojunction devices.

  4. Surface protection of light metals by one-step laser cladding with oxide ceramics

    Science.gov (United States)

    Nowotny, S.; Richter, A.; Tangermann, K.

    1999-06-01

    Today, intricate problems of surface treatment can be solved through precision cladding using advanced laser technology. Metallic and carbide coatings have been produced with high-power lasers for years, and current investigations show that laser cladding is also a promising technique for the production of dense and precisely localized ceramic layers. In the present work, powders based on Al2O3 and ZrO2 were used to clad aluminum and titanium light alloys. The compact layers are up to 1 mm thick and show a nonporous cast structure as well as a homogeneous network of vertical cracks. The high adhesive strength is due to several chemical and mechanical bonding mechanisms and can exceed that of plasmasprayed coatings. Compared to thermal spray techniques, the material deposition is strictly focused onto small functional areas of the workpiece. Thus, being a precision technique, laser cladding is not recommended for large-area coatings. Examples of applications are turbine components and filigree parts of pump casings.

  5. Tubular solid oxide fuel cells with porous metal supports and ceramic interconnections

    Science.gov (United States)

    Huang, Kevin [Export, PA; Ruka, Roswell J [Pittsburgh, PA

    2012-05-08

    An intermediate temperature solid oxide fuel cell structure capable of operating at from 600.degree. C. to 800.degree. C. having a very thin porous hollow elongated metallic support tube having a thickness from 0.10 mm to 1.0 mm, preferably 0.10 mm to 0.35 mm, a porosity of from 25 vol. % to 50 vol. % and a tensile strength from 700 GPa to 900 GPa, which metallic tube supports a reduced thickness air electrode having a thickness from 0.010 mm to 0.2 mm, a solid oxide electrolyte, a cermet fuel electrode, a ceramic interconnection and an electrically conductive cell to cell contact layer.

  6. The electronic conduction of glass and glass ceramics containing various transition metal oxides

    International Nuclear Information System (INIS)

    Yoshida, T.; Matsuno, Y.

    1980-01-01

    Nb 2 O 5 -V 2 O 5 -P 2 O 5 glasses containing only Group Va oxides have been investigated to elucidate their electronic conduction and structure, as compared with other glasses obtained by the addition of various transition metal oxides to vanadium phosphate. The P 2 O 5 introduction for Nb 2 O 5 in this glass with the same amount of V 2 O 5 increased the conductivity about two times. Glass ceramics having high conductivity increased by two orders of magnitude and the activation energy for conduction decreased from about 0.5 to 0.2 eV. The crystals were confirmed to be (V,Nb) 2 O 5 and Nb phosphate, one of which was highly conductive and developed a pillar-like shape with a length of more than 20 μm. (orig.)

  7. Effects of single pulse energy on the properties of ceramic coating prepared by micro-arc oxidation on Ti alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jun-Hua [Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471023 (China); Faculty of Mechanical and Electrical Engineering, Kunming University of Science and Technology, Kunming 650500 (China); Wang, Jin [Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Beijing Key Lab of Precision/Ultra-precision Manufacturing Equipments and Control, Beijing 100084 (China); Lu, Yan [School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471023 (China); Du, Mao-Hua [Faculty of Mechanical and Electrical Engineering, Kunming University of Science and Technology, Kunming 650500 (China); Han, Fu-Zhu, E-mail: hanfuzhu@mail.tsinghua.edu.cn [Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Beijing Key Lab of Precision/Ultra-precision Manufacturing Equipments and Control, Beijing 100084 (China)

    2015-01-01

    Highlights: • Single pulse energy remarkably influences the properties of ceramic coating prepared by MAO on Ti alloy. • The accumulative time of impulse width is an important parameter in the scientific and rational measurement of the film forming law of ceramic coating. • The ceramic coating thickness approximately linearly increases with the cumulative time of impulse width. • Larger impulse width resulted in higher single pulse energy, film forming rates and thicker ceramic coating thickness. • The effects of single pulse energy on the micro-hardness and phase composition of ceramic coating are not as evident as those of frequency and duty cycle. - Abstract: The effects of single pulse energy on the properties of ceramic coating fabricated on a Ti–6Al–4V alloy via micro-arc oxidation (MAO) in aqueous solutions containing aluminate, phosphate, and some additives are investigated. The thickness, micro-hardness, surface and cross-sectional morphology, surface roughness, and compositions of the ceramic coating are studied using eddy current thickness meter, micro-hardness tester, JB-4C Precision Surface roughness meter, scanning electron microscopy (SEM) and X-ray diffraction (XRD). Single pulse energy remarkably influences the ceramic coating properties. The accumulative time of impulse width is an important parameter in the scientific and rational measurement of the film forming law of ceramic coating. The ceramic coating thickness approximately linearly increases with the cumulative time of impulse width. Larger impulse width resulted in higher single pulse energy, film forming rates and thicker ceramic coating thickness. The sizes of oxide particles, micro-pores and micro-cracks slightly increase with impulse width and single pulse energy. The main surface conversion products generated during MAO process in aqueous solutions containing aluminate are rutile TiO{sub 2}, anatase TiO{sub 2}, and a large amount of Al{sub 2}TiO{sub 5}. The effects of

  8. Structure and in vitro bioactivity of ceramic coatings on magnesium alloys by microarc oxidation

    Science.gov (United States)

    Yu, Huijun; Dong, Qing; Dou, Jinhe; Pan, Yaokun; Chen, Chuanzhong

    2016-12-01

    Magnesium and its alloys have the potential to serve as lightweight, degradable, biocompatible and bioactive orthopedic implants for load-bearing applications. However, severe local corrosion attack and high corrosion rate have prevented their further clinical use. Micro-arc oxidation (MAO) is proved to be a simple, controllable and efficient electrochemistry technique that can prepare protective ceramic coatings on magnesium alloys. In this paper, electrolyte containing silicate salts was used for microarc oxidation to form ceramic bioactive coatings on the ZK61 alloy substrate. The structure characteristics and element distributions of the coating were investigated by XRD, TEM, SEM and EPMA. The MAO samples were immersed in simulated body fluid (SBF) for 7 and 14 days, respectively. The surface characteristic of the immersed coatings was investigated by Fourier-transform infrared (FTIR) spectroscopy. The results show that these MAO coatings have low crystallinity and are mainly composed of MgO, Mg2SiO4 and Mg2Si2O6. The coating surface is porous. During the SBF immersion period, the nucleation and precipitation of bone-like apatites occur on the MAO coating surface. The corrosion resistance of the substrate is improved by the MAO coatings.

  9. Inverted bulk-heterojunction organic solar cell using chemical bath deposited titanium oxide as electron collection layer

    OpenAIRE

    Kuwabara, Takayuki; Sugiyama, Hirokazu; Kuzuba, Mitsuhiro  ; Yamaguchi, Takahiro; Takahashi, Kohshin

    2010-01-01

    Chemical bath deposited titanium oxide (TiOx ) as an electron collection layer is introduced between the organic layer and the indium tin oxide (ITO) electrode for improving the performance of inverted bulk-heterojunction organic thin film solar cells with 1 cm2 active area, where regioregular poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) were mainly used as the photo-active layer. The uniform and thin TiOx film was easily prepared onto the ITO electrode ...

  10. Atomic layer deposition of titanium oxide films on As-synthesized magnetic Ni particles: Magnetic and safety properties

    Energy Technology Data Exchange (ETDEWEB)

    Uudeküll, Peep, E-mail: peep.uudekull@ut.ee [Institute of Physics, University of Tartu, W. Ostwaldi Str.1, 50411 Tartu (Estonia); Kozlova, Jekaterina; Mändar, Hugo [Institute of Physics, University of Tartu, W. Ostwaldi Str.1, 50411 Tartu (Estonia); Link, Joosep [Laboratory of Chemical Physics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn (Estonia); Sihtmäe, Mariliis [Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn (Estonia); Käosaar, Sandra [Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn (Estonia); Faculty of Chemical and Materials Technology, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); Blinova, Irina; Kasemets, Kaja; Kahru, Anne [Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn (Estonia); Stern, Raivo [Laboratory of Chemical Physics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn (Estonia); Tätte, Tanel [Institute of Physics, University of Tartu, W. Ostwaldi Str.1, 50411 Tartu (Estonia); Kukli, Kaupo [Institute of Physics, University of Tartu, W. Ostwaldi Str.1, 50411 Tartu (Estonia); University of Helsinki, Department of Chemistry, P.O. Box 55, FI-00014 Helsinki (Finland); Tamm, Aile [Institute of Physics, University of Tartu, W. Ostwaldi Str.1, 50411 Tartu (Estonia)

    2017-05-01

    Spherical nickel particles with size in the range of 100–400 nm were synthesized by non-aqueous liquid phase benzyl alcohol method. Being developed for magnetically guided biomedical applications, the particles were coated by conformal and antimicrobial thin titanium oxide films by atomic layer deposition. The particles retained their size and crystal structure after the deposition of oxide films. The sensitivity of the coated particles to external magnetic fields was increased compared to that of the uncoated powder. Preliminary toxicological investigations on microbial cells and small aquatic crustaceans revealed non-toxic nature of the synthesized particles.

  11. Atomic layer deposition of titanium oxide films on As-synthesized magnetic Ni particles: Magnetic and safety properties

    International Nuclear Information System (INIS)

    Uudeküll, Peep; Kozlova, Jekaterina; Mändar, Hugo; Link, Joosep; Sihtmäe, Mariliis; Käosaar, Sandra; Blinova, Irina; Kasemets, Kaja; Kahru, Anne; Stern, Raivo; Tätte, Tanel; Kukli, Kaupo; Tamm, Aile

    2017-01-01

    Spherical nickel particles with size in the range of 100–400 nm were synthesized by non-aqueous liquid phase benzyl alcohol method. Being developed for magnetically guided biomedical applications, the particles were coated by conformal and antimicrobial thin titanium oxide films by atomic layer deposition. The particles retained their size and crystal structure after the deposition of oxide films. The sensitivity of the coated particles to external magnetic fields was increased compared to that of the uncoated powder. Preliminary toxicological investigations on microbial cells and small aquatic crustaceans revealed non-toxic nature of the synthesized particles.

  12. Hybrid TiO2: polymer photovoltaic cells made from a titanium oxide precursor

    NARCIS (Netherlands)

    Slooff, L.H.; Wienk, M.M.; Kroon, J.M.

    2004-01-01

    Hybrid TiO2:polymer photovoltaic cells were made from mixtures of titanium(IV) isopropoxide and poly[2-methoxy-5-(3',7'-dimethyloctyl)-p-phenylene vinylene] (MDMO-PPV) or poly(3-octyl thiophene) (P3OT) via hydrolysis in air. Cells were made with varying titanium(IV) isopropoxide:polymer ratios.

  13. Aluminum Oxide Nanoparticles for Highly Efficient Asphaltene Separation from Crude Oil Using Ceramic Membrane Technology

    Directory of Open Access Journals (Sweden)

    Rezakazemi Mashallah

    2017-11-01

    Full Text Available The effects of aluminum oxide nanoparticles on the removal of asphaltenes from an Iranian crude oil (Soroush using a ceramic membrane with pore size of 0.2 µm were investigated. In order to achieve superior asphaltene separation by ultrafiltration, it is essential to make some changes for destabilizing asphaltene in crude oil. The asphaltene destabilization was done using crude oil contact with an acid containing dissolved metal ions. Metal oxide nanoparticles adsorbed asphaltene molecules and increased their molecular size. The nanoparticle of aluminum oxide was applied to alter precipitation and peptization properties of asphaltenes. Dynamic Light Scattering (DLS was used to measurement of the asphaltene molecular size dissolved in toluene. Raman spectroscopy and the Tuinstra equation were used to determine the aromatic sheet diameter (La via the integrated intensities of the G and D1 modes. This revealed that the asphaltene particles react with nano aluminum oxide and the average molecular size of asphaltene was raised from 512.754 to 2949.557 nm and La from 5.482 to 13.787. The obtained results showed that using nano aluminum oxides, asphaltene separation increased from 60–85 wt% to 90–97 wt% based on the asphaltene content of crude oil.

  14. Oxidation Study of an Ultra High Temperature Ceramic Coatings Based on HfSiCN

    Science.gov (United States)

    Sacksteder, Dagny; Waters, Deborah L.; Zhu, Dongming

    2018-01-01

    High temperature fiber-reinforced ceramic matrix composites (CMCs) are important for aerospace applications because of their low density, high strength, and significantly higher-temperature capabilities compared to conventional metallic systems. The use of the SiCf/SiC and Cf/SiC CMCs allows the design of lighter-weight, more fuel efficient aircraft engines and also more advanced spacecraft airframe thermal protection systems. However, CMCs have to be protected with advanced environmental barrier coatings when they are incorporated into components for the harsh environments such as in aircraft engine or spacecraft applications. In this study, high temperature oxidation kinetics of an advanced HfSiCN coating on Cf/SiC CMC substrates were investigated at 1300 C, 1400 C, and 1500 C by using thermogravimetric analysis (TGA). The coating oxidation reaction parabolic rate constant and activation energy were estimated from the experimental results. The oxidation reaction studies showed that the coatings formed the most stable, predominant HfSiO4-HfO2 scales at 1400 C. A peroxidation test at 1400 C then followed by subsequent oxidation tests at various temperatures also showed more adherent scales and slower scale growth because of reduced the initial transient oxidation stage and increased HfSiO4-HfO2 content in the scales formed on the HfSiCN coatings.

  15. Oxide_Oxide Ceramic Matrix Composite (CMC) Exhaust Mixer Development in the NASA Environmentally Responsible Aviation (ERA) Project

    Science.gov (United States)

    Kiser, J. Douglas; Bansal, Narottam P.; Szelagowski, James; Sokhey, Jagdish; Heffernan, Tab; Clegg, Joseph; Pierluissi, Anthony; Riedell, Jim; Wyen, Travis; Atmur, Steven; hide

    2015-01-01

    LibertyWorks®, a subsidiary of Rolls-Royce Corporation, first studied CMC (ceramic matrix composite) exhaust mixers for potential weight benefits in 2008. Oxide CMC potentially offered weight reduction, higher temperature capability, and the ability to fabricate complex-shapes for increased mixing and noise suppression. In 2010, NASA was pursuing the reduction of NOx emissions, fuel burn, and noise from turbine engines in Phase I of the Environmentally Responsible Aviation (ERA) Project (within the Integrated Systems Research Program). ERA subtasks, including those focused on CMC components, were being formulated with the goal of maturing technology from Proof of Concept Validation (Technology Readiness Level 3 (TRL 3)) to System/Subsystem or Prototype Demonstration in a Relevant Environment (TRL 6). LibertyWorks®, a subsidiary of Rolls-Royce Corporation, first studied CMC (ceramic matrix composite) exhaust mixers for potential weight benefits in 2008. Oxide CMC potentially offered weight reduction, higher temperature capability, and the ability to fabricate complex-shapes for increased mixing and noise suppression. In 2010, NASA was pursuing the reduction of NOx emissions, fuel burn, and noise from turbine engines in Phase I of the Environmentally Responsible Aviation (ERA) Project (within the Integrated Systems Research Program). ERA subtasks, including those focused on CMC components, were being formulated with the goal of maturing technology from Proof of Concept Validation (Technology Readiness Level 3 (TRL 3)) to System/Subsystem or Prototype Demonstration in a Relevant Environment (TRL 6). Oxide CMC component at both room and elevated temperatures. A TRL˜5 (Component Validation in a Relevant Environment) was attained and the CMC mixer was cleared for ground testing on a Rolls-Royce AE3007 engine for performance evaluation to achieve TRL 6.

  16. Phase constituents and microstructure of laser cladding Al{sub 2}O{sub 3}/Ti{sub 3}Al reinforced ceramic layer on titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Li Jianing [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Department of Materials Science, Shandong University, Jing Shi Road 17923, Jinan 250061, Shandong (China); Chen Chuanzhong, E-mail: czchen@sdu.edu.cn [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Department of Materials Science, Shandong University, Jing Shi Road 17923, Jinan 250061, Shandong (China); Lin Zhaoqing [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Department of Materials Science, Shandong University, Jing Shi Road 17923, Jinan 250061, Shandong (China); Squartini, Tiziano [INFM - Department of Physics, Siena University, Siena 53100 (Italy)

    2011-04-07

    Research highlights: > In this study, Fe{sub 3}Al has been chosen as cladding powder due to its excellent properties of wear resistance and high strength, etc. > Laser cladding of Fe{sub 3}Al + TiB{sub 2}/Al{sub 2}O{sub 3} pre-placed alloy powder on Ti-6Al-4V alloy substrate can form the Ti{sub 3}Al/Fe{sub 3}Al + TiB{sub 2}/Al{sub 2}O{sub 3} ceramic layer, which can increase wear resistance of substrate. > In cladding process, Al{sub 2}O{sub 3} can react with TiB{sub 2} leading to formation of Ti{sub 3}Al and B. > This principle can be used to improve the Fe{sub 3}Al + TiB{sub 2} laser-cladded coating. - Abstract: Laser cladding of the Fe{sub 3}Al + TiB{sub 2}/Al{sub 2}O{sub 3} pre-placed alloy powder on Ti-6Al-4V alloy can form the Ti{sub 3}Al/Fe{sub 3}Al + TiB{sub 2}/Al{sub 2}O{sub 3} ceramic layer, which can greatly increase wear resistance of titanium alloy. In this study, the Ti{sub 3}Al/Fe{sub 3}Al + TiB{sub 2}/Al{sub 2}O{sub 3} ceramic layer has been researched by means of electron probe, X-ray diffraction, scanning electron microscope and micro-analyzer. In cladding process, Al{sub 2}O{sub 3} can react with TiB{sub 2} leading to formation of amount of Ti{sub 3}Al and B. This principle can be used to improve the Fe{sub 3}Al + TiB{sub 2} laser cladded coating, it was found that with addition of Al{sub 2}O{sub 3}, the microstructure performance and micro-hardness of the coating was obviously improved due to the action of the Al-Ti-B system and hard phases.

  17. The Effect of Luting Cement and Titanium Base on the Final Color of Zirconium Oxide Core Material.

    Science.gov (United States)

    Capa, Nuray; Tuncel, Ilkin; Tak, Onjen; Usumez, Aslihan

    2017-02-01

    To evaluate the effects of different types of luting cements and different colors of zirconium cores on the final color of the restoration that simulates implant-supported fixed partial dentures (FPDs) by using a titanium base on the bottom. One hundred and twenty zirconium oxide core plates (Zr-Zahn; 10 mm in width, 5 mm in length, 0.5 mm in height) were prepared in different shades (n = 20; noncolored, A2, A3, B1, C2, D2). The specimens were subdivided into two subgroups for the two types of luting cements (n = 10). The initial color measurements were made on zirconium oxide core plates using a spectrometer. To create the cement thicknesses, stretch strips with holes in the middle (5 mm in diameter, 70 μm in height) were used. The second measurement was done on the zirconium oxide core plates after the application of the resin cement (U-200, A2 Shade) or polycarboxylate cement (Lumicon). The final measurement was done after placing the titanium discs (5 mm in diameter, 3 mm in height) in the bottom. The data were analyzed with two-way ANOVA and Tukey's honestly significant differences (HSD) tests (α = 0.05). The ∆E* ab value was higher in the resin cement-applied group than in the polycarboxylate cement-applied group (p zirconium oxide core-resin cement-titanium base, and the lowest was recorded for the polycarboxylate cement-zirconium oxide core (p zirconium are all important factors that determine the final shade of zirconia cores in implant-supported FPDs. © 2015 by the American College of Prosthodontists.

  18. Photocatalytic and electrochemical properties of single- and multi-layer sub-stoichiometric titanium oxide coatings prepared by atmospheric plasma spraying

    Czech Academy of Sciences Publication Activity Database

    Ctibor, Pavel; Seshadri, R.C.; Henych, Jiří; Nehasil, V.; Pala, Zdeněk; Kotlan, Jiří

    2016-01-01

    Roč. 5, č. 2 (2016), s. 126-136 ISSN 2226-4108 Institutional support: RVO:61389021 ; RVO:61388980 Keywords : titanium dioxide * stoichiometry * feedstock * spectroscopic techniques Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass; CA - Inorganic Chemistry (UACH-T) Impact factor: 1.198, year: 2016 http://link.springer.com/article/10.1007/s40145-016-0181-5

  19. Inorganic ion exchanger based on tin/titanium mixed oxide doped with europium to be used in radioactive waste

    International Nuclear Information System (INIS)

    Paganini, Paula P.; Felinto, Maria Claudia F.C.; Kodaira, Claudia A.; Brito, Hermi F.

    2009-01-01

    This work presents the results of synthesis and characterization of an inorganic ion exchanger based on tin/titanium mixed oxides doped with europium (SnO 2 /TiO 2 :Eu 3+ ) to be used in environmental field. The adsorption study of nickel was realized in this exchanger to recover the nickel metal which is in thorium-nickel alloys used as electrode of discharge lamps. The studied exchanger was synthesized by neutralization of tin chloride (IV) and titanium chloride (III) mixed solution and characterized by thermogravimetric measurement (TG), Differential Scanning Calorimetry (DSC), X-Ray Powder Diffraction (XRD), Infrared Spectroscopy (IR) and Scanning Electron Microscopy (SEM). The adsorption study showed that these inorganic ion exchangers are good materials to recovery nickel with high weight distribution ratios (Dw Ni 2+ ) and percent adsorption. (author)

  20. Self-cleaning glass coating containing titanium oxide and silicon; Revestimentos autolimpantes para vidros contendo oxido de titanio e silicio

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, A.O. de; Alves, A.K.; Berutti, F.A.; Bergmann, C.P. [Universidade Federal do Rio Grande do Sul (LACER/UFRGS), Porto Alegre, RS (Brazil). Lab. de Materiais Ceramicos

    2009-07-01

    Using the electro spinning technique nano fibers of titanium oxide doped with silicon were synthesized. As precursor materials, titanium propoxide, silicon tetra propoxide and a solution of polyvinylpyrrolidone were used. The non-tissue material obtained was characterized by X-ray diffraction to determine the phase and crystallite size, BET method to determine the surface and SEM to analyze the microstructure of the fibers. After ultrasound dispersion of this material in ethanol, the glass coatings were made by dip-coating methodology. The influence of the removal velocity, the solution composition and the glass surface preparation were evaluated. The film was characterized by the contact angle of a water droplet in its surface. (author)

  1. Trimetallic oxide nanocomposites of transition metals titanium and vanadium by sol-gel technique: synthesis, characterization and electronic properties

    Science.gov (United States)

    Kumar, Amit; Mishra, Neeraj Kumar; Sachan, Komal; Ali, Md Asif; Soaham Gupta, Sachchidanand; Singh, Rajeev

    2018-04-01

    Novel titanium and vanadium based trimetallic oxide nanocomposites (TMONCs) have been synthesized using metal salts of titanium-vanadium along with three others metals viz. tin, aluminium and zinc as precursors by the sol-gel method. Aqueous ammonia and hydrazine hydrate were used as the reducing agents. The preparations of nanocomposites were monitored by observing the visual changes during each step of synthesis. The synthesized TMONCs were characterized using UV–vis, SEM, EDX, TEM and DLS. Band gap of the synthesized TMONCs ranges from 3–4.5 eV determined using tauc plot. FTIR study revealed the molecular stretching and bending peaks of corresponding M–O/M–O–M bonds thus confirming their formation. Molecular composition and particle size were determined using EDX and DLS respectively. Molecular shape, size and surface morphology have been examined by SEM and TEM.

  2. Treatment of secondary effluent by sequential combination of photocatalytic oxidation with ceramic membrane filtration.

    Science.gov (United States)

    Song, Lili; Zhu, Bo; Jegatheesan, Veeriah; Gray, Stephen; Duke, Mikel; Muthukumaran, Shobha

    2018-02-01

    The aim of the present work was to experimentally evaluate an alternative advanced wastewater treatment system, which combines the action of photocatalytic oxidation with ceramic membrane filtration. Experiments were carried out using laboratory scale TiO 2 /UV photocatalytic reactor and tubular ceramic microfiltration (CMF) system to treat the secondary effluent (SE). A 100-nm pore size CMF membrane was investigated in cross flow mode under constant transmembrane pressure of 20 kPa. The results show that specific flux decline of CMF membrane with and without TiO 2 /UV photocatalytic treatment was 30 and 50%, respectively, after 60 min of filtration. Data evaluation revealed that the adsorption of organic compounds onto the TiO 2 particles was dependent on the pH of the suspension and was considerably higher at low pH. The liquid chromatography-organic carbon detector (LC-OCD) technique was used to characterise the dissolved organic matter (DOM) present in the SE and was monitored following photocatalysis and CMF. The results showed that there was no removal of biopolymers and slight removal of humics, building blocks and the other oxidation by-products after TiO 2 /UV photocatalytic treatment. This result suggested that the various ions present in the SE act as scavengers, which considerably decrease the efficiency of the photocatalytic oxidation reactions. On the other hand, the CMF was effective for removing 50% of biopolymers with no further removal of other organic components after photocatalytic treatment. Thus, the quantity of biopolymers in SE has an apparent correlation with the filterability of water samples in CMF.

  3. Compatibility of sodium with ceramic oxides employed in nuclear reactors; Compatibilidad del sodio con oxidos ceramicos utilizados en reactores nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Acena Moreno, V

    1981-07-01

    This work is a review of experiments carried out up to the present time on the corrosion and compatibility of ceramic oxides with liquid sodium at temperatures corresponding to those in fast breeder reactors. The review also includes the results of a thermo-dynamic/liquid sodium reactions. The exercise has been conducted with a view to effecting experimental studies in the future. (Author)

  4. Measurement and modelling of the defect chemistry and transport properties of ceramic oxide mixed ionic and electronic conductors

    DEFF Research Database (Denmark)

    Dalslet, Bjarke Thomas

    2008-01-01

    The subject of this thesis is ceramic mixed ionic and electronic conductors (MIECs). MIECs have potential uses, such as solid oxygen permeation membranes, as catalysts, and as components in fuel cells. The MIECs examined in this thesis are all oxide ion conducting materials. This thesis describes...

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

    International Nuclear Information System (INIS)

    Garcia, Rafael Henrique Lazzari

    2007-01-01

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

  6. Investigating the structure and biocompatibility of niobium and titanium oxides as coatings for orthopedic metallic implants.

    Science.gov (United States)

    Pradhan, D; Wren, A W; Misture, S T; Mellott, N P

    2016-01-01

    Applying sol gel based coatings to orthopedic metallic implant materials can significantly improve their properties and lifespan in vivo. For this work, niobium (Nb2O5) and titanium (TiO2) oxides were prepared via solution processing in order to determine the effect of atomic arrangement (amorphous/crystalline) on bioactivity. Thermal evaluation on the synthesized materials identified an endotherm for Nb2O5 at 75 °C with 40% weight loss below 400 °C, and minimal weight loss between 400 and 850 °C. Regarding TiO2 an endotherm was present at 92 °C with 25% weight loss below 400 °C, and 4% between 400 and 850 °C. Phase evolution was determined using High Temperature X-ray Diffraction (HT-XRD) where amorphous-Nb2O5 (450 °C), hexagonal-Nb2O5 (525 °C), orthorhombic-Nb2O5 (650 °C), amorphous-TiO2 (275 °C) and tetragonal TiO2 (500 °C) structures were produced. Simulated body fluid (SBF) testing was conducted over 1, 7 and 30 days and resulted in positive chemical and morphological changes for crystalline Nb2O5 (525 °C) and TiO2 (500 °C) after 30 days of incubation. Rod-like CaP deposits were observed on the surfaces using Scanning Electron Microscopy (FE-SEM) and Grazing Incidence-X-ray Diffraction (GI-XRD) shows that the deposits were X-ray amorphous. Cell viability was higher with the TiO2 (122%) samples when compared to the growing cell population while Nb2O5 samples exhibited a range of viability (64-105%), partially dependent on materials atomic structure. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Electrolytic trichloroethene degradation using mixed metal oxide coated titanium mesh electrodes.

    Science.gov (United States)

    Petersen, Matthew A; Sale, Thomas C; Reardon, Kenneth F

    2007-04-01

    Electrochemical systems provide a low cost, versatile, and controllable platform to potentially treat contaminants in water, including chlorinated solvents. Relative to bare metal or noble metal amended materials, dimensionally stable electrode materials such as mixed metal oxide coated titanium (Ti/MMO) have advantages in terms of stability and cost, important factors for sustainable remediation solutions. Here, we report the use of Ti/MMO as an effective cathode substrate for treatment of trichloroethene (TCE). TCE degradation in a batch reactor was measured as the decrease of TCE concentration over time and the corresponding evolution of chloride; notably, this occurred without the formation of commonly encountered chlorinated intermediates. The reaction was initiated when Ti/MMO cathode potentials were less than -0.8 V vs. the standard hydrogen electrode, and the rate of TCE degradation increased linearly with progressively more negative potentials. The maximum pseudo-first-order heterogeneous rate constant was approximately 0.05 cm min(-1), which is comparable to more commonly used cathode materials such as nickel. In laboratory-scale flow-though column reactors designed to simulate permeable reactive barriers (PRBs), TCE concentrations were reduced by 80-90%. The extent of TCE flux reduction increased with the applied potential difference across the electrodes and was largely insensitive to the spacing distance between the electrodes. This is the first report of the electrochemical reduction of a chlorinated organic contaminant at a Ti/MMO cathode, and these results support the use of this material in PRBs as a possible approach to manage TCE plume migration.

  8. Novel titanium oxide nanoparticles for effective delivery of paclitaxel to human breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Mund, R., E-mail: rachnamund@gmail.com; Panda, N., E-mail: niladri1panda@gmail.com [National Institute of Technology, Department of Biotechnology and Medical Engineering (India); Nimesh, S., E-mail: surendranimesh@curaj.ac.in [Central University of Rajasthan, Department of Biotechnology, School of Life Sciences (India); Biswas, A., E-mail: amitb79@gmail.com [National Institute of Technology, Department of Biotechnology and Medical Engineering (India)

    2014-12-15

    Novel titanium oxide (TiO{sub 2}) nanoparticles were fabricated via a modified propanol drying step. These nanoparticles were loaded with anti-cancer drug paclitaxel (PTX) to yield PTX-TiO{sub 2} nanocomposites. The nanocomposites were characterized for their size and surface morphology employing nanoparticle tracking analysis (NTA) and scanning electron microscopy (SEM). The SEM images showed spherical particles with smooth surface and narrow size distribution of ∼30–40 nm, which was also supported by NTA analysis data. The drug loading efficiency of the air-dried nanoparticles was observed to be ∼63.61 % while those prepared through propanol-induced drying step showed ∼69.70 %, thereby demonstrating higher efficiency of the latter. In vitro pH-dependent release of the loaded PTX was observed with higher release at acidic pH compared with physiological pH. Cell uptake studies suggested of time-dependent internalization of nanocomposites with significant improvement in uptake by increasing incubation time from 2 to 24 h, as evidenced by flow cytometry. Further, the cell viability as a measure of anti-cancer activity revealed that cell viability upon exposure to PTX only was 40.5 % while that of PTX-TiO{sub 2} nanocomposite showed 21.6 % viability after 24 h, suggesting better anti-cancer efficacy of nanocomposites. Apoptosis studies revealed that cells treated with PTX-TiO{sub 2} nanocomposites possessed more amount of apoptotic bodies as compared to those treated with PTX only.

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

    International Nuclear Information System (INIS)

    Arakaki, Alexander Rodrigo

    2010-01-01

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

  10. Application of photo-excitation reaction on titanium oxide thin film for control of wettability; Sanka chitann hakumakujo no hikari reiki hanno no nuresei seigyo eno oyo

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, T.; Nakajima, A.; Hashimoto, K. [The Univ. of Tokyo, Tokyo (Japan); Takada, Y. [Kyushu Univ., Fukuoka (Japan)

    2000-03-31

    It is clarified that the photo-excitation hydrophilic reaction increasing wettability remarkably is induced by changing surface structure of titanium oxide radiated light. There are already many examples being in practical use of coating products applied hydrophilic reaction of titanium oxide surface such as drip-proof side millers for automobiles, self-cleaning building materials, and the like. When surface of titanium oxide having high activities for oxidisation and decomposition is coated organic materials and radiated light, wettability of surface changes as organic materials are decomposed. If it is possible to change wettability shaping pattern drastically by radiating light, the possibility of application for printing materials will be developed. After increasing contact angle by coating water and oil repellent on the titanium oxide thin film, images can be shaped by radiating light into pattern for changing surface of titanium oxide to be ultra hydrophilicity as decomposition of repellent. At that time, contact angle is 150 degree in water, 80 degree in oil, for not radiated aria, and is 0 degree in water and oil for radiated aria. Application for control technology of wettability keeps possibility of broader development to itself, not staying ability of self-cleaning and drip-proof. (NEDO)

  11. Assessment of antibacterial and cytotoxic effects of orthodontic stainless steel brackets coated with different phases of titanium oxide: An in-vitro study.

    Science.gov (United States)

    Baby, Roshen Daniel; Subramaniam, Siva; Arumugam, Ilakkiya; Padmanabhan, Sridevi

    2017-04-01

    Our objective was to assess the antibacterial and cytotoxic effects of orthodontic stainless steel brackets coated with different phases of photocatalytic titanium oxide. From a total sample of 115 brackets, 68 orthodontic stainless steel brackets were coated with titanium oxide using a radiofrequency magnetron sputtering machine. The coated brackets were then converted into 34 each of the anatase and rutile phases of titanium oxide. These brackets were subdivided into 4 groups for antibacterial study and 3 groups for cytotoxicity study. Brackets for the antibacterial study were assessed against the Streptococcus mutans species using microbiologic tests. Three groups for the cytotoxicity study were assessed using the thiazolyl tetrazolium bromide assay. The antibacterial study showed that both phases were effective, but the rutile phase of photocatalytic titanium oxide had a greater bactericidal effect than did the anatase phase. The cytotoxicity study showed that the rutile phase had a greater decrease in viability of cells compared with the anatase phase. It is recommended that orthodontic brackets be coated with the anatase phase of titanium oxide since they exhibited a significant antibacterial property and were only slightly cytotoxic. Copyright © 2016 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

  12. PERFORMANCE OF EVACUATED TUBE SOLAR COLLECTOR USING WATER-BASED TITANIUM OXIDE NANOFLUID

    Directory of Open Access Journals (Sweden)

    M. Mahendran

    2012-12-01

    Full Text Available Experiments are undertaken to determine the efficiency of an evacuated tube solar collector using water-based Titanium Oxide (TiO2 nanofluid at the Pekan Campus (3˚32’ N, 103˚25’ E, Faculty of Mechanical Engineering, University Malaysia Pahang, for the conversion of solar thermal energy. Malaysia lies in the equatorial zone with an average daily solar insolation of more than 900 W/m², which can reach a maximum of 1200 W/m² for most of the year. Traditionally water is pumped through the collector at an optimum flow rate, for the extraction of solar thermal energy. If the outlet temperature of the water is high, further circulation of the water through the collector is useless. This is due to the low thermal conductivity of water of 0.6 W/m.K compared to metals which is many orders higher. Hence it is necessary to reduce the surface temperature either by pumping water at a higher flow rate or by enhancing the fluid’s properties by the dispersion of nanoparticles. Pumping water at higher flow rates is not advantageous as the overall efficiency of the system is lowered. Liquids in which nanosized particles of metal or their oxides are dispersed in a base liquid such as water are known as 'Nanofluids'. This results in higher values of thermal conductivity compared to the base liquid. The thermal conductivity increases with the concentration and temperature of the nanofluid. The increase in thermal conductivity with temperature is advantageous for application in collectors as the solar insolation varies throughout the day, with a minimum in the morning reaching a maximum at 2.00p.m and reducing thereafter. The efficiency of the collector estimated using a TiO2 nanofluid of 0.3% concentration is about 0.73, compared to water which is about 0.58. The efficiency is enhanced by 16.7% maximum with 30–50nm sized TiO2 nanoparticles dispersed in the water, compared to the system working solely with water. The flow rate is fixed at 2.7 liters per

  13. Spectrographic determination of impurities in ceramic materials for nuclear fusion reactors III. Analysis of magnesium oxide

    International Nuclear Information System (INIS)

    Melon, A. M.; Roca, M.; Rucandio, M. I.

    1992-01-01

    The determination of minor and trace elements in the magnesium oxide, considered as possible ceramic material in thermonuclear fusion reactors, has been studied. The concentration ranges are 0.1 - 0.3% for Ca, Si and Y, and at the ppm level for Al, Co, Cr, Fe, Hf, K, Li, Mn, Na, Ni, Se, Ti, V and Zr. Atomic emission spectroscopy with direct current are excitation and photographic detection has been employed. In order to eliminate the effect due to the differences in density between standards and samples, which are a source of errors, a chemical treatment of both is carried out. Likewise, for attaining conditions more suitable for the volatilization of certain impurities, these are determined with the sample in fluoride form. (Author) 11 refs

  14. Spectrographic determination of impurities in ceramic materials for nuclear fusion reactors III. Analysis of magnesium oxide

    International Nuclear Information System (INIS)

    Melon, A.M.; Roca, M.; Rucandio, M.I.

    1992-01-01

    The determination of minor and trace elements in the magnesium oxide, considered as possible ceramic material in thermonuclear fusion reactors, has been studied. The concentration ranges are 0.1 - 0.3 % for Ca, Si and Y, and at the ppm level for Al, Co, Cr, Fe, Hf, K, Li, Mn, Na, Ni, Sc, Ti, V and Zr. Atomic emission spectroscopy with direct current arc excitation and photographic detection has been employed. In order to eliminated the effect due to the differences in density between standards and samples, which are a source of errors, a chemical treatment of both is carried out. Likewise, for attaining conditions more suitable for the volatilization of certain impurities, these are determined with the sample in fluoride form. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-08-30

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

  16. Retention of implant-supported zirconium oxide ceramic restorations using different luting agents.

    Science.gov (United States)

    Nejatidanesh, Farahnaz; Savabi, Omid; Shahtoosi, Mojtaba

    2013-08-01

    The aim of this study was to evaluate the retention value of implant-supported zirconium oxide ceramic copings using different luting agents. Twenty ITI solid abutments of 5.5 mm height and ITI implant analogs were mounted vertically into autopolymerizing acrylic resin blocks. Ninety zirconium oxide copings (Cercon, Degudent) with a loop on the occlusal portion were made. All samples were airborne particle abraded with 110 μm Al₂O₃ and luted using different types of luting agents: resin cements (Clearfil SA, Panavia F2.0, Fuji Plus), conventional cements (Fleck's, Poly F, Fuji I), and temporary cements (Temp Bond, GC free eugenol, TempSpan) with a load of 5 Kg. (N = 10) All copings were incubated at 37°C for 24 h and conditioned in artificial saliva for 1 week, and thermal cycled for 5000 cycles 5-55°C with a 30-s dwell time. The dislodging force of the copings along the long axis of the implant-abutment complex was recorded using universal testing machine with 5 mm/min crosshead speed. Data were subjected to Kruskal-Wallis (α = 0.05) and Mann-Whitney tests with Bonferroni step down correction (α = 0.001). There was significant difference between the mean rank retention values of different luting agents (P zirconium oxide restorations. © 2011 John Wiley & Sons A/S.

  17. Polypyrrole–titanium(IV) doped iron(III) oxide nanocomposites: Synthesis, characterization with tunable electrical and electrochemical properties

    International Nuclear Information System (INIS)

    Nandi, Debabrata; Ghosh, Arup Kumar; Gupta, Kaushik; De, Amitabha; Sen, Pintu; Duttachowdhury, Ankan; Ghosh, Uday Chand

    2012-01-01

    Highlights: ► Synthesis and characterization of polymer nanocomposite based on titanium doped iron(III) oxide. ► Electrical conductivity increased 100 times in composite with respect to polymer. ► Electrochemical capacitance of polymer composites increased with nanooxide content. ► Thermal stability of the polymer enhanced with nano oxide content. -- Abstract: Titanium(IV)-doped synthetic nanostructured iron(III) oxide (NITO) and polypyrrole (PPy) nanocomposites was fabricated by in situ polymerization using FeCl 3 as initiator. The polymer nanocomposites (PNCs) and pure NITO were characterized by X-ray diffraction, Föurier transform infrared spectroscopy, scanning electron microscopy, electron dispersive X-ray spectroscopy, transmission electron microscopy, etc. Thermo gravimetric and differential thermal analyses showed the enhancement of thermal stability of PNCs than the pure polymer. Electrical conductivity of the PNCs had increased significantly from 0.793 × 10 −2 S/cm to 0.450 S/cm with respect to the PPy, and that had been explained by 3-dimensional variable range hopping (VRH) conduction mechanisms. In addition, the specific capacitance of PNCs had increased from 147 F/g to 176 F/g with increasing NITO content than that of pure NITO (26 F/g), presumably due to the growing of mesoporous structure with increasing NITO content in PNCs which reduced the charge transfer resistance significantly.

  18. Effect of surface treatments on the bond strength between resin cement and differently sintered zirconium-oxide ceramics.

    Science.gov (United States)

    Yenisey, Murat; Dede, Doğu Ömür; Rona, Nergiz

    2016-01-01

    This study investigated the effects of surface treatments on bond strength between resin cement and differently sintered zirconium-oxide ceramics. 220 zirconium-oxide ceramic (Ceramill ZI) specimens were prepared, sintered in two different period (Short=Ss, Long=Ls) and divided into ten treatment groups as: GC, no treatment; GSil, silanized (ESPE-Sil); GSilPen, silane flame treatment (Silano-Pen); GSb, sandblasted; GSbSil, sandblasted+silanized; GSbCoSil, sandblasted+silica coated (CoJet)+silanized; GSbRoSil, sandblasted+silica coated (Rocatech-Plus)+silanized; GSbDSil, sandblasted+diamond particle abraded (Micron MDA)+silanized; GSbSilPen, sandblasted+silane flame treatment+silanized; GSbLSil, sandblasted+Er:Yag (Asclepion-MCL30) laser treated+silanized. The composite resin (Filtek Z-250) cylinders were cemented to the treated ceramic surfaces with a resin cement (Panavia F2.0). Shear bond strength test was performed after specimens were stored in water for 24h and thermo-cycled for 6000 cycles (5-55 °C). Data were statistically analyzed with two-way analysis of variance (ANOVA) and Tamhane's multiple comparison test (α=0.05). According to the ANOVA, sintering time, surface treatments and their interaction were statistically significant (pzirconium-oxide ceramics. Copyright © 2015 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  19. Metallorganic routes to nanoscale iron and titanium oxide particles encapsulated in mesoporous alumina: formation, physical properties, and chemical reactivity.

    Science.gov (United States)

    Schneider, J J; Czap, N; Hagen, J; Engstler, J; Ensling, J; Gütlich, P; Reinoehl, U; Bertagnolli, H; Luis, F; de Jongh, L J; Wark, M; Grubert, G; Hornyak, G L; Zanoni, R

    2000-12-01

    Iron and titanium oxide nanoparticles have been synthesized in parallel mesopores of alumina by a novel organometallic "chimie douce" approach that uses bis(toluene)iron(0) (1) and bis(toluene)titanium(0) (2) as precursors. These complexes are molecular sources of iron and titanium in a zerovalent atomic state. In the case of 1, core shell iron/iron oxide particles with a strong magnetic coupling between both components, as revealed by magnetic measurements, are formed. Mössbauer data reveal superparamagnetic particle behavior with a distinct particle size distribution that confirms the magnetic measurements. The dependence of the Mössbauer spectra on temperature and particle size is explained by the influence of superparamagnetic relaxation effects. The coexistence of a paramagnetic doublet and a magnetically split component in the spectra is further explained by a distribution in particle size. From Mössbauer parameters the oxide phase can be identified as low-crystallinity ferrihydrite oxide. In agreement with quantum size effects observed in UV-visible studies, TEM measurements determine the size of the particles in the range 5-8 nm. The particles are mainly arranged alongside the pore walls of the alumina template. TiO2 nanoparticles are formed by depositing 2 in mesoporous alumina template. This produces metallic Ti, which is subsequently oxidized to TiO2 (anatase) within the alumina pores. UV-visible studies show a strong quantum confinement effect for these particles. From UV-visible investigations the particle size is determined to be around 2 nm. XPS analysis of the iron- and titania- embedded nanoparticles reveal the presence of Fe2O3 and TiO2 according to experimental binding energies and the experimental line shapes. Ti4+ and Fe3+ are the only oxidation states of the particles which can be determined by this technique. Hydrogen reduction of the iron/iron-oxide nanoparticles at 500 degrees C under flowing H2/N2 produces a catalyst, which is active

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

    Institute of Scientific and Technical Information of China (English)

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

    2004-01-01

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

  1. Ti 2p and O 1s core levels and chemical bonding in titanium-bearing oxides

    International Nuclear Information System (INIS)

    Atuchin, Victor V.; Kesler, Valery G.; Pervukhina, Natalia V.; Zhang, Zhaoming

    2006-01-01

    A set of available experimental data on the binding energies of Ti 2p 3/2 and O 1s core levels in titanium-bearing oxides has been presented by using the binding energy difference (O 1s-Ti 2p 3/2 ) as a robust parameter to characterize these compounds. An empirical relationship between the (O 1s-Ti 2p 3/2 ) values measured with XPS and the mean chemical bond length L(Ti-O) in these crystals has been discussed for Ti 4+ -compounds

  2. Ti 2p and O 1s core levels and chemical bonding in titanium-bearing oxides

    Energy Technology Data Exchange (ETDEWEB)

    Atuchin, Victor V. [Laboratory of Optical Materials and Structures, Institute of Semiconductor Physics, SB RAS, Novosibirsk 630090 (Russian Federation)]. E-mail: atuchin@thermo.isp.nsc.ru; Kesler, Valery G. [Technical Centre, Institute of Semiconductor Physics, SB RAS, Novosibirsk 630090 (Russian Federation); Pervukhina, Natalia V. [Laboratory of Crystal Chemistry, Institute of Inorganic Chemistry, SB RAS, Novosibirsk 630090 (Russian Federation); Zhang, Zhaoming [Australian Nuclear Science and Technology Organisation, PMB 1, Menai, NSW 2234 (Australia)

    2006-06-15

    A set of available experimental data on the binding energies of Ti 2p{sub 3/2} and O 1s core levels in titanium-bearing oxides has been presented by using the binding energy difference (O 1s-Ti 2p{sub 3/2}) as a robust parameter to characterize these compounds. An empirical relationship between the (O 1s-Ti 2p{sub 3/2}) values measured with XPS and the mean chemical bond length L(Ti-O) in these crystals has been discussed for Ti{sup 4+}-compounds.

  3. A Glass-Ceramic Waste Forms for the Immobilization of Rare Earth Oxides from the Pyroprocessing Waste salt

    International Nuclear Information System (INIS)

    Ahn, Byung-Gil; Park, Hwan-Seo; Kim, Hwan-Young; Kim, In-Tae

    2008-01-01

    The fission product of rare earth (RE) oxide wastes are generates during the pyroprocess . Borosilicate glass or some ceramic materials such as monazite, apatite or sodium zirconium phosphate (NZP) have been a prospective host matrix through lots of experimental results. Silicate glasses have long been the preferred waste form for the immobilization of HLW. In immobilization of the RE oxides, the developed process on an industrial scale involves their incorporation into a glass matrix, by melting under 1200 ∼ 1300 .deg. C. Instead of the melting process, glass powder sintering is lower temperature (∼ 900 .deg. C) required for the process which implies less demanding conditions for the equipment and a less evaporation of volatile radionuclides. This study reports the behaviors, direct vitrification of RE oxides with glass frit, glass powder sintering of REceramic with glass frit, formation of RE-apatite (or REmonazite) ceramic according to reaction temperature, and the leach resistance of the solidified waste forms

  4. Laser-induced oxidation of titanium substrate: Analysis of the physicochemical structure of the surface and sub-surface layers

    Energy Technology Data Exchange (ETDEWEB)

    Antończak, Arkadiusz J., E-mail: arkadiusz.antonczak@pwr.edu.pl [Laser and Fiber Electronics Group, Faculty of Electrical Engineering, Wroclaw University of Technology, Wyb. Wyspianskiego 27, 50-370 Wroclaw (Poland); Skowroński, Łukasz; Trzcinski, Marek [Institute of Mathematics and Physics, University of Technology and Life Sciences, Kaliskiego 7, 85-789 Bydgoszcz (Poland); Kinzhybalo, Vasyl V. [Wroclaw Research Centre EIT+, Stabłowicka 147, 54-066 Wrocław (Poland); Institute of Low Temperature and Structure Research, Okólna 2, 50-422 Wrocław (Poland); Łazarek, Łukasz K.; Abramski, Krzysztof M. [Laser and Fiber Electronics Group, Faculty of Electrical Engineering, Wroclaw University of Technology, Wyb. Wyspianskiego 27, 50-370 Wroclaw (Poland)

    2015-01-15

    Highlights: • Chemical structure of the films induced by laser on titanium surface was analyzed. • It was shown that outer layer of this films consist of oxides doped with nitrogen. • The optical properties of the laser-induced oxynitride films were characterized. • We found that the films demonstrated significant absorption in the band of 300–580 nm. • The morphology of the layers as a function of the laser fluence was investigated. - Abstract: This paper presents the results of the analysis of the complex chemical structure of the layers made on titanium in the process of the heating of its surfaces in an atmospheric environment, by irradiating samples with a nanosecond-pulsed laser. The study was carried out for electroplated, high purity, polycrystalline titanium substrates using a Yb:glass fiber laser. All measurements were made for samples irradiated in a broad range of accumulated fluence, below the ablation threshold. It has been determined how the complex index of refraction of both the oxynitride layers and the substrate vary as a function of accumulated laser fluence. It was also shown that the top layer of the film produced on titanium, which is transparent, is not a pure TiO{sub 2} as had been supposed before. The XPS and XRD analyses confirmed the presence of nitrogen compounds and the existence of nonstoichiometric compounds. By sputtering of the sample's surface using an Ar{sup +} ion gun, the changes in the concentration of individual elements as a function of the layer's cross-section were determined. Lastly, an analysis of the surface morphology has also been carried out, explaining why the layers crack and exfoliate from their substrate.

  5. Nanosized lead lanthanum titanate (PLT) ceramic powders synthesized by the oxidant peroxo method

    Energy Technology Data Exchange (ETDEWEB)

    Camargo, Emerson R. [LIEC-Laboratorio Interdisciplinar de Eletroquimica e Ceramica, Department of Chemistry, UFSCar-Federal University of Sao Carlos, Rod.Washingtin Luis km 235, CP 676, Sao Carlos SP 13565-9905 (Brazil)], E-mail: camargo@ufscar.br; Barrado, Cristiano M. [LIEC-Laboratorio Interdisciplinar de Eletroquimica e Ceramica, Department of Chemistry, UFSCar-Federal University of Sao Carlos, Rod.Washingtin Luis km 235, CP 676, Sao Carlos SP 13565-9905 (Brazil); Ribeiro, Caue [EMBRAPA Instrumentacao Agropecuaria, Rua XV de Novembro 1452, Sao Carlos SP 13560-970 (Brazil)], E-mail: caue@cnpdia.embrapa.br; Longo, Elson [Department of Biochemistry, Chemistry Institute of Araraquara, UNESP-Sao Paulo State University, Rua Francisco Degni, CP 355, Araraquara SP 14801-907 (Brazil)], E-mail: elson@iq.unesp.br; Leite, Edson R. [LIEC-Laboratorio Interdisciplinar de Eletroquimica e Ceramica, Department of Chemistry, UFSCar-Federal University of Sao Carlos, Rod.Washingtin Luis km 235, CP 676, Sao Carlos SP 13565-9905 (Brazil)], E-mail: derl@power.ufscar.br

    2009-05-05

    For the first time it is reported the synthesis of lead titanate modified with rare earth by the oxidant-peroxo method (OPM). Lanthanum was added up to 20% in mol through the dissolution of lanthanum oxide in nitric acid, followed by the addition of a solution of lead and lanthanum nitrate into an aqueous solution of titanium peroxo complexes. The amorphous precipitate formed was heat-treated at different temperatures in the range from 400 to 900 deg. C for crystallization. Powders were characterized by Raman spectroscopy and X-ray diffraction. Tetragonal perovskite structure was observed for the samples up to 15% of lanthanum substitution and cubic perovskite for sample with 20% of lanthanum. Crystallographic domains calculated by Scherrer equation showing a probable suppression of the crystallite growth in function of lanthanum content. It was observed shifting to lower frequencies of Raman modes in the range between 100 and 400 cm{sup -1} and the vanishing of the A1(2TO) and E(1LO) modes could be attributed to transition phase from tetragonal to cubic. Electronic microscopy image revealed that the powders annealed at height temperature are spherical with sharp size distribution.

  6. Nanosized lead lanthanum titanate (PLT) ceramic powders synthesized by the oxidant peroxo method

    International Nuclear Information System (INIS)

    Camargo, Emerson R.; Barrado, Cristiano M.; Ribeiro, Caue; Longo, Elson; Leite, Edson R.

    2009-01-01

    For the first time it is reported the synthesis of lead titanate modified with rare earth by the oxidant-peroxo method (OPM). Lanthanum was added up to 20% in mol through the dissolution of lanthanum oxide in nitric acid, followed by the addition of a solution of lead and lanthanum nitrate into an aqueous solution of titanium peroxo complexes. The amorphous precipitate formed was heat-treated at different temperatures in the range from 400 to 900 deg. C for crystallization. Powders were characterized by Raman spectroscopy and X-ray diffraction. Tetragonal perovskite structure was observed for the samples up to 15% of lanthanum substitution and cubic perovskite for sample with 20% of lanthanum. Crystallographic domains calculated by Scherrer equation showing a probable suppression of the crystallite growth in function of lanthanum content. It was observed shifting to lower frequencies of Raman modes in the range between 100 and 400 cm -1 and the vanishing of the A1(2TO) and E(1LO) modes could be attributed to transition phase from tetragonal to cubic. Electronic microscopy image revealed that the powders annealed at height temperature are spherical with sharp size distribution.

  7. Effect of SUS316L stainless steel surface conditions on the wetting of molten multi-component oxides ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jin, E-mail: wangjinustb@gmail.com [Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Fukuoka, 808-0196 (Japan); Matsuda, Nozomu [Bar and Wire Product Unit, Nippon steel and Sumitomo Metal Corporation, Fukuoka, 802-8686 (Japan); Shinozaki, Nobuya [Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Fukuoka, 808-0196 (Japan); Miyoshi, Noriko [The Center for Instrumental Analysis, Kyushu Institute of Technology, Fukuoka, 804-8550 (Japan); Shiraishi, Takanobu [Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, 852-8588 (Japan)

    2015-02-01

    Highlights: • Multi-component oxides had a good wetting on stainless substrates with pretreatments. • Various substrates surface roughness caused the difference of final contact angles. • The wetting rate was slow on polished substrate due to the slow surface oxidation. - Abstract: A study on the effect of SUS316L stainless steel surface conditions on the wetting behavior of molten multi-component oxides ceramic was performed and aimed to contribute to the further understanding of the application of oxides ceramic in penetration treatment of stainless steel coatings and the deposition of stainless steel cermet coatings. The results show that at 1273 K, different surface pre-treatments (polishing and heating) had an important effect on the wetting behavior. The molten multi-component oxides showed good wettability on both stainless steel substrates, however, the wetting process on the polished substrate was significantly slower than that on the heated substrates. The mechanism of the interfacial reactions was discussed based on the microscopic and thermodynamic analysis, the substrates reacted with oxygen generated from the decomposition of the molten multi-component oxides and oxygen contained in the argon atmosphere, and the oxide film caused the molten multi-component oxides ceramic to spread on the substrates surfaces. For the polished substrate, more time was required for the surface oxidation to reach the surface composition of Heated-S, which resulted in relatively slow spreading and wetting rates. Moreover, the variance of the surface roughness drove the final contact angles to slightly different values following the sequence Polished-S > Heated-S.

  8. Exposure to titanium dioxide and other metallic oxide nanoparticles induces cytotoxicity on human neural cells and fibroblasts

    Directory of Open Access Journals (Sweden)

    James C K Lai

    2008-12-01

    Full Text Available James C K Lai1, Maria B Lai1, Sirisha Jandhyam1, Vikas V Dukhande1, Alok Bhushan1, Christopher K Daniels1, Solomon W Leung21Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, and Biomedical Research Institute; 2Department of Civil and Environmental Engineering, College of Engineering and Biomedical Research Institute, Idaho State University, Pocatello, ID, USAAbstract: The use of titanium dioxide (TiO2 in various industrial applications (eg, production of paper, plastics, cosmetics, and paints has been expanding thereby increasing the occupational and other environmental exposure of these nanoparticles to humans and other species. However, the health effects of exposure to TiO2 nanoparticles have not been systematically assessed even though recent studies suggest that such exposure induces inflammatory responses in lung tissue and cells. Because the effects of such nanoparticles on human neural cells are unknown, we have determined the putative cytotoxic effects of these nanoparticles on human astrocytes-like astrocytoma U87 cells and compared their effects on normal human fibroblasts. We found that TiO2 micro- and nanoparticles induced cell death on both human cell types in a concentration-related manner. We further noted that zinc oxide (ZnO nanoparticles were the most effective, TiO2 nanoparticles the second most effective, and magnesium oxide (MgO nanoparticles the least effective in inducing cell death in U87 cells. The cell death mechanisms underlying the effects of TiO2 micro- and nanoparticles on U87 cells include apoptosis, necrosis, and possibly apoptosis-like and necrosis-like cell death types. Thus, our findings may have toxicological and other pathophysiological implications on exposure of humans and other mammalian species to metallic oxide nanoparticles.Keywords: cytotoxicity of titanium dioxide micro- and nanoparticles, cytotoxicity of zinc oxide and magnesium oxide nanoparticles, human neural cells

  9. Summary of ceramic pigments by polymer precursors Pechini method

    International Nuclear Information System (INIS)

    Silva, E.M. da; Galvao, S.B.; Paskocimas, C.A.

    2010-01-01

    In this work were synthesized nitrate chromium nitrate and iron-doped titanium oxide by the polymeric precursor method, for application as ceramic pigments. The stains were developed between the temperatures 700 deg C to 1000 deg C, in green for chromium oxide and orange for iron. Noticing an increase of its opacity by increasing temperature. Characterization by thermogravimetry (TG) showed strong thermo decomposition from 355 deg C for the chromium oxide and thermo decomposition gradual for the iron. By analysis of X-ray diffraction revealed the formation of crystalline phases as Iron Titanate (FeTiO3) and Chrome Titanate (CrTiO3), respectively. The scanning electron microscopy showed the formation of rounded particles for both oxides. Thus, the synthesized oxides were within the requirements to be applied as pigments and shown to be possible to propose its use in ceramic materials. (author)

  10. Uranyl ion sorption mechanisms on titanium oxide: a multi-scale approach

    International Nuclear Information System (INIS)

    Vandenborre, J.; Drot, R.; Simoni, E.; Dong, W.; Du, J.; Dossot, M.; Humbert, B.; Ehrhardt, J.J.

    2005-01-01

    Full text of publication follows: Radionuclides retention mechanisms onto mineral phases is of primary importance for nuclear waste management. The aim of the presented study is to demonstrate that it is possible to predict the retention properties of a methodological powdery substrate from the study of its natural crystallographic orientations. Among the radionuclides of interest, U(VI) can be seen as a model of the radionuclides oxo-cations. The substrate under study is the titanium oxide (TiO 2 ). In fact, rutile can be found as powder and also as manufactured single crystal which allows to study the retention processes on perfectly known crystallographic planes. Since the repartition of the different crystallographic orientations are known for the powder, the results obtained for the single crystals can directly be used to account for the powder retention properties. By using combined spectroscopic techniques such as TRLFS, XPS, DRIFT and SHG, it is possible to determine the nature of the reactive surface sites and also the surface species. XPS and TRLFS measurements allowed to determine that two same uranyl surface species were formed on titania (110) and (001). Only, the relative intensities of these species vary with the surface coverage. Atomic Force Microscopy was carried out to verify that no surface precipitation occurs for the higher surface coverages. Moreover, these analysis have also evidenced that the U(VI) sorption is homogeneous. These observations were corroborated by SHG experiments (mainly for (001)) which have also shown that the sorption occurs, in a first step, onto preferential surface symmetry axis. For rutile powder, the preferential crystallographic orientations are (110), (100) and (101) in the ratio 60/20/20. TRLFS and XPS experiments have shown that two uranyl surface species are formed whatever the pH value ranged from 1 to 5. The spectroscopic characteristics of these species are the same as the ones observed on (110) and (001

  11. Titanium dioxide and zinc oxide nanoparticles in sunscreens: focus on their safety and effectiveness

    Directory of Open Access Journals (Sweden)

    Smijs TG

    2011-10-01

    Full Text Available Threes G Smijs1–3, Stanislav Pavel4 1Faculty of Science, Open University in The Netherlands, Rotterdam, The Netherlands; 2University of Leiden, Leiden Amsterdam Center for Drug Research, Leiden, The Netherlands; 3Erasmus MC, Center for Optical Diagnostics and Therapy, Rotterdam, The Netherlands; 4Charles University, Faculty of Medicine, Department of Dermatology, Pilsen, Czech Republic Abstract: Sunscreens are used to provide protection against adverse effects of ultraviolet (UVB (290–320 nm and UVA (320–400 nm radiation. According to the United States Food and Drug Administration, the protection factor against UVA should be at least one-third of the overall sun protection factor. Titanium dioxide (TiO2 and zinc oxide (ZnO minerals are frequently employed in sunscreens as inorganic physical sun blockers. As TiO2 is more effective in UVB and ZnO in the UVA range, the combination of these particles assures a broad-band UV protection. However, to solve the cosmetic drawback of these opaque sunscreens, microsized TiO2 and ZnO have been increasingly replaced by TiO2 and ZnO nanoparticles (NPs (<100 nm. This review focuses on significant effects on the UV attenuation of sunscreens when microsized TiO2 and ZnO particles are replaced by NPs and evaluates physicochemical aspects that affect effectiveness and safety of NP sunscreens. With the use of TiO2 and ZnO NPs, the undesired opaqueness disappears but the required balance between UVA and UVB protection can be altered. Utilization of mixtures of micro- and nanosized ZnO dispersions and nanosized TiO2 particles may improve this situation. Skin exposure to NP-containing sunscreens leads to incorporation of TiO2 and ZnO NPs in the stratum corneum, which can alter specific NP attenuation properties due to particle–particle, particle–skin, and skin–particle–light physicochemical interactions. Both sunscreen NPs induce (photocyto- and genotoxicity and have been sporadically observed in viable

  12. Ultrafine titanium dioxide particles in the absence of photoactivation can induce oxidative damage to human bronchial epithelial cells

    International Nuclear Information System (INIS)

    Gurr, J.-R.; Wang, Alexander S.S.; Chen, C.-H.; Jan, K.-Y.

    2005-01-01

    Ultrafine titanium dioxide (TiO 2 ) particles have been shown to exhibit strong cytotoxicity when exposed to UVA radiation, but are regarded as a biocompatible material in the absence of photoactivation. In contrast to this concept, the present results indicate that anatase-sized (10 and 20 nm) TiO 2 particles in the absence of photoactivation induced oxidative DNA damage, lipid peroxidation, and micronuclei formation, and increased hydrogen peroxide and nitric oxide production in BEAS-2B cells, a human bronchial epithelial cell line. However, the treatment with anatase-sized (200 and >200 nm) particles did not induce oxidative stress in the absence of light irradiation; it seems that the smaller the particle, the easier it is for the particle to induce oxidative damage. The photocatalytic activity of the anatase form of TiO 2 was reported to be higher than that of the rutile form. In contrast to this notion, the present results indicate that rutile-sized 200 nm particles induced hydrogen peroxide and oxidative DNA damage in the absence of light but the anatase-sized 200 nm particles did not. In total darkness, a slightly higher level of oxidative DNA damage was also detected with treatment using an anatase-rutile mixture than with treatment using either the anatase or rutile forms alone. These results suggest that intratracheal instillation of ultrafine TiO 2 particles may cause an inflammatory response

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

    Science.gov (United States)

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

    2013-08-01

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

  14. Titanium dioxide nanoparticles induce oxidative stress and DNA-adduct formation but not DNA-breakage in human lung cells

    Directory of Open Access Journals (Sweden)

    Schins Roel PF

    2009-06-01

    Full Text Available Abstract Titanium dioxide (TiO2, also known as titanium (IV oxide or anatase, is the naturally occurring oxide of titanium. It is also one of the most commercially used form. To date, no parameter has been set for the average ambient air concentration of TiO2 nanoparticles (NP by any regulatory agency. Previously conducted studies had established these nanoparticles to be mainly non-cyto- and -genotoxic, although they had been found to generate free radicals both acellularly (specially through photocatalytic activity and intracellularly. The present study determines the role of TiO2-NP (anatase, ∅ in vitro. For comparison, iron containing nanoparticles (hematite, Fe2O3, ∅ 2-NP did not induce DNA-breakage measured by the Comet-assay in both cell types. Generation of reactive oxygen species (ROS was measured acellularly (without any photocatalytic activity as well as intracellularly for both types of particles, however, the iron-containing NP needed special reducing conditions before pronounced radical generation. A high level of DNA adduct formation (8-OHdG was observed in IMR-90 cells exposed to TiO2-NP, but not in cells exposed to hematite NP. Our study demonstrates different modes of action for TiO2- and Fe2O3-NP. Whereas TiO2-NP were able to generate elevated amounts of free radicals, which induced indirect genotoxicity mainly by DNA-adduct formation, Fe2O3-NP were clastogenic (induction of DNA-breakage and required reducing conditions for radical formation.

  15. Industrial ceramics - Properties, forming and applications

    International Nuclear Information System (INIS)

    Fantozzi, Gilbert; Niepce, Jean-Claude; Bonnefont, Guillaume; Alary, J.A.; Allard, B.; Ayral, A.; Bassat, J.M.; Elissalde, C.; Maglione, M.; Beauvy, M.; Bertrand, G.; Bignon, A.; Billieres, D.; Blanc, J.J.; Blumenfeld, P.; Bonnet, J.P.; Bougoin, M.; Bourgeon, M.; Boussuge, M.; Thorel, A.; Bruzek, C.E.; Cambier, F.; Carrerot, H.; Casabonne, J.M.; Chaix, J.M.; Chevalier, J.; Chopinet, M.H.; Couque, H.; Courtois, C.; Leriche, A.; Dhaler, D.; Denape, J.; Euzen, P.; Ganne, J.P.; Gauffinet, S.; Girard, A.; Gonon, M.; Guizard, C.; Hampshire, S.; Joulin, J.P.; Julbe, A.; Ferrato, M.; Fontaine, M.L.; Lebourgeois, R.; Lopez, J.; Maquet, M.; Marinel, S.; Marrony, M.; Martin, J.F.; Mougin, J.; Pailler, R.; Pate, M.; Petitpas, E.; Pijolat, C.; Pires-Franco, P.; Poirier, C.; Poirier, J.; Pourcel, F.; Potier, A.; Tulliani, J.M.; Viricelle, J.P.; Beauger, A.

    2013-01-01

    After a general introduction to ceramics (definition, general properties, elaboration, applications, market data), this book address conventional ceramics (elaboration, material types), thermo-structural ceramics (oxide based ceramics, non-oxide ceramics, fields of application, functional coatings), refractory ceramics, long fibre and ceramic matrix composites, carbonaceous materials, ceramics used for filtration, catalysis and the environment, ceramics for biomedical applications, ceramics for electronics and electrical engineering (for capacitors, magnetic, piezoelectric, dielectric ceramics, ceramics for hyper-frequency resonators), electrochemical ceramics, transparent ceramics (forming and sintering), glasses, mineral binders. The last chapter addresses ceramics used in the nuclear energy sector: in nuclear fuels and fissile material, absorbing ceramics and shields, in the management of nuclear wastes, new ceramics for reactors under construction or for future nuclear energy

  16. Nano-oxides to improve the surface properties of ceramic tiles

    Directory of Open Access Journals (Sweden)

    Timellini, G.

    2010-10-01

    Full Text Available The aim of the present work is to realise ceramic tiles with superior surface mechanical characteristics and chemical resistance, by the addition of nano-oxides, such as zirconia and alumina, since such advanced ceramics oxides are well known for their excellent mechanical properties and good resistance to chemical etching. In order to avoid any dangerousness, the nanoparticles were used in form of aqueous suspension and they were sprayed, by airbrush, directly onto the dried ceramic support, before firing. To observe the distribution of the nanoparticles and to optimise the surface treatment, SEM-EDS analyses were carried out on the fired samples. XRD analysis was conducted to assess the phases evolution of the different materials during the firing step. The surface mechanical characteristics of the samples have been evaluated by Vickers’ hardness and scratch test. In addition, also chemical resistance tests were performed. Microstructural observations allowed to understand how alumina and zirconia nanoparticles acted to improve the surface performances of the modified ceramic tiles.

    La finalidad de este trabajo es la de realizar baldosas con mejores características mecánicas superficiales, al incorporar óxidos de partículas nanométricas, como la circona y la alúmina, ya que se sabe que estos óxidos confieren unas propiedades mecánicas excelentes además de una buena resistencia al ataque químico. Para evitar cualquier peligro, las partículas nanométricas se usaron en forma de suspensión acuosa y se pulverizaron, por medio de un aerógrafo, directamente sobre el soporte cerámico seco, antes de la cocción. Para observar la distribución de las partículas nanométricas y para optimizar el tratamiento de la superficie, se realizó unos análisis por MEB-EDS sobre las muestras cocidas. Se llevó a cabo un análisis de difracción de rayos X (DRX para evaluar la evolución de las fases de los distintos materiales durante

  17. Process Developed for Generating Ceramic Interconnects With Low Sintering Temperatures for Solid Oxide Fuel Cells

    Science.gov (United States)

    Zhong, Zhi-Min; Goldsby, Jon C.

    2005-01-01

    Solid oxide fuel cells (SOFCs) have been considered as premium future power generation devices because they have demonstrated high energy-conversion efficiency, high power density, and extremely low pollution, and have the flexibility of using hydrocarbon fuel. The Solid-State Energy Conversion Alliance (SECA) initiative, supported by the U.S. Department of Energy and private industries, is leading the development and commercialization of SOFCs for low-cost stationary and automotive markets. The targeted power density for the initiative is rather low, so that the SECA SOFC can be operated at a relatively low temperature (approx. 700 C) and inexpensive metallic interconnects can be utilized in the SOFC stack. As only NASA can, the agency is investigating SOFCs for aerospace applications. Considerable high power density is required for the applications. As a result, the NASA SOFC will be operated at a high temperature (approx. 900 C) and ceramic interconnects will be employed. Lanthanum chromite-based materials have emerged as a leading candidate for the ceramic interconnects. The interconnects are expected to co-sinter with zirconia electrolyte to mitigate the interface electric resistance and to simplify the processing procedure. Lanthanum chromites made by the traditional method are sintered at 1500 C or above. They react with zirconia electrolytes (which typically sinter between 1300 and 1400 C) at the sintering temperature of lanthanum chromites. It has been envisioned that lanthanum chromites with lower sintering temperatures can be co-fired with zirconia electrolyte. Nonstoichiometric lanthanum chromites can be sintered at lower temperatures, but they are unstable and react with zirconia electrolyte during co-sintering. NASA Glenn Research Center s Ceramics Branch investigated a glycine nitrate process to generate fine powder of the lanthanum-chromite-based materials. By simultaneously doping calcium on the lanthanum site, and cobalt and aluminum on the

  18. Preparation of titanium oxide and metal titanates as powders, thin films, and microspheres by complex sol-gel process

    International Nuclear Information System (INIS)

    Deptula, A.; Olczak, T.; Lada, W.; Chmielewski, A.G.; Jakubaszek, U.; Sartowska, B.; Goretta, K.C.; Alvani, C.; Casadio, S.; Contini, V.

    2006-01-01

    Titanium oxide, for many years an important pigment, has recently been applied widely as a photocatalyst or as supports for metallic catalysts, gas sensors, photovoltaic solar cells, and water and air purification devices. Titanium oxide (TiO 2 ) and titanates based on Ba, Sr and Ca were prepared from commercial solutions of TiCl 4 and HNO 3 . The main preparation steps for the sols consisted of elimination of Cl - by distillation with HNO 3 and addition of metal hydroxides for the titanates. Resulting sols were gelled and used to: (a) prepare irregularly shaped powders by evaporation; (b) produce by a dipping technique thin films on glass, Ag or Ti supports; (c) produce spherical powders (diameters <100 μm) by solvent extraction. Results of thermal and X-ray-diffraction analyses indicated that the temperatures required to form the various compounds were lower than those necessary to form the compounds by conventional solid-state reactions and comparable to those required with use of organometallic based sol-gel methods. Temperatures of formation could be further reduced by addition of ascorbic acid (ASC) to the sols

  19. Synthesis and characterization of mixtures of cobalt and titanium oxides by mechanical alloyed and Sol-Gel

    International Nuclear Information System (INIS)

    Basurto S, R.; Bonifacio M, J.; Fernandez V, S. M.

    2009-01-01

    The mechanical alloyed techniques continued by combustion and Sol-Gel method, were used for the synthesis of CoTiO 3 . With the first technique was used Co 3 O 4 obtained in a balls mill SPEX in argon atmosphere, using cobalt nitrate and urea, the combustion is realized at 400 and 500 C, the characterization by X-ray diffraction showed the obtaining of the valence oxide mixed of cobalt with crystallite size from 10 to 12.5 nm and the particle size of 60 to 75 nm was obtained by scanning electron microscopy. To prepare the CoTiO 3 , the obtained Co 3 O 4 was mixed with TiO 2 on a relationship in weight (1:1) and with a milling time of 2.5 h and the combustion at 800 C. the mixed oxide of titanium cobalt was also obtained by the Sol-Gel technique starting from cobalt chloride and titanium propoxide in acetic-water acid, the gel is burned to temperature of 300, 500, 700 and 900 C, finding that this last temperature it is that provides the compound with crystalline size from 50 to 75 nm. (Author)

  20. Chromium–tungsten–titanium mixed oxides solid catalyst for fatty acid methyl ester synthesis from palm fatty acid distillate

    International Nuclear Information System (INIS)

    Wan, Zuraida; Hameed, B.H.

    2014-01-01

    Highlights: • Chromium–tungsten–titanium mixed oxides as solid catalyst. • Catalyst used for esterification of palm fatty acid distillate to methyl esters. • The maximum methyl ester content is 83%. • Catalyst has shown good activity and can be recycled for 4 times. - Abstract: Chromium–tungsten–titanium mixed oxides solid catalysts were prepared and evaluated in the esterification of palm fatty acid distillate (PFAD) to produce fatty acid methyl ester (FAME). Esterification was conducted in a batch reactor at 110–200 °C temperature ranges. The catalysts were characterized by several techniques such as BET, TEM, FTIR, TGA, XRD, EDX and SEM. The treatment conditions during catalyst preparation, effect of reaction parameters, leaching of the active species and the recycled use of the catalyst were investigated. The catalyst with formula CrWTiO 2 was found to be the most active with maximum FAME content of 83% obtained at best reaction conditions of 170 °C for 3 h, 2:1 (methanol to oil molar ratio) and 2 wt.% catalyst dosage. The catalyst can be recycled for 4 times. The results revealed CrWTiO 2 good potentials for use in esterification of high acid value oil

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-10-15

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

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  3. Variable electron beam diameter achieved by a titanium oxide/carbon nanotube hetero-structure suitable for nanolithography

    International Nuclear Information System (INIS)

    Abdi, Yaser; Barati, Fatemeh

    2013-01-01

    We report the fabrication of a titanium oxide/carbon nanotube based field emission device suitable for nanolithography and fabrication of transistors. The growth of carbon nanotubes (CNTs) is performed on silicon substrates using a plasma-enhanced chemical vapor deposition method. The vertically grown CNTs are encapsulated by titanium oxide (TiO 2 ) using an atmospheric pressure chemical vapor deposition system. Field emission from the CNTs is realized by mechanical polishing of the prepared structure. Possible applications of such nanostructures as a lithography tool with variable electron beam diameter has been investigated. The obtained results show that a spot size of less than 30 nm can be obtained by applying the proper voltage on TiO 2 surrounding gate. Electrical measurements of the fabricated device confirm the capability of the structure for fabrication of field emission based field effect transistors. By a voltage applied between the gate and the cathode electrode, the emission current from CNTs shows a significant drop, indicating proper control of the gate on the emission current. (paper)

  4. Alloying element's substitution in titanium alloy with improved oxidation resistance and enhanced magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Ang-Yang, E-mail: ayyu@imr.ac.cn; Wei, Hua; Hu, Qing-Miao; Yang, Rui

    2017-01-15

    First-principles method is used to characterize segregation and magnetic properties of alloyed Ti/TiO{sub 2}interface. We calculate the segregation energy of the doped Ti/TiO{sub 2} interface to investigate alloying atom's distribution. The oxidation resistance of Ti/TiO{sub 2} interface is enhanced by elements Fe and Ni but reduced by element Co. Magnetism could be produced by alloying elements such as Co, Fe and Ni in the bulk of titanium and the surface of Ti at Ti/TiO{sub 2} interface. The presence of these alloying elements could transform the non-magnetic titanium alloys into magnetic systems. We have also calculated the temperature dependence of magnetic permeability for the doped and pure Ti/TiO{sub 2} interfaces. Alloying effects on the Curie temperature of the Ti/TiO{sub 2} interface have been elaborated. - Highlights: • We consider the segregation of alloying atoms on the Ti(101¯0)/TiO{sub 2}(100) interface. • Alloying the Ti//TiO{sub 2} interface with Fe and Ni has a great advantage of improving the oxidation resistance. • Fe, Co and Nican enhance the magnetic properties of the investigated system. • The variation of permeability with temperature has been presented.

  5. Sol–gel synthesis of tantalum oxide and phosphonic acid-modified carbon nanotubes composite coatings on titanium surfaces

    International Nuclear Information System (INIS)

    Maho, Anthony; Detriche, Simon; Delhalle, Joseph; Mekhalif, Zineb

    2013-01-01

    Carbon nanotubes used as fillers in composite materials are more and more appreciated for the outstanding range of accessible properties and functionalities they generate in numerous domains of nanotechnologies. In the framework of biological and medical sciences, and particularly for orthopedic applications and devices (prostheses, implants, surgical instruments, …), titanium substrates covered by tantalum oxide/carbon nanotube composite coatings have proved to constitute interesting and successful platforms for the conception of solid and biocompatible biomaterials inducing the osseous regeneration processes (hydroxyapatite growth, osteoblasts attachment). This paper describes an original strategy for the conception of resistant and homogeneous tantalum oxide/carbon nanotubes layers on titanium through the introduction of carbon nanotubes functionalized by phosphonic acid moieties (-P(=O)(OH) 2 ). Strong covalent C-P bonds are specifically inserted on their external sidewalls with a ratio of two phosphonic groups per anchoring point. Experimental results highlight the stronger “tantalum capture agent” effect of phosphonic-modified nanotubes during the sol–gel formation process of the deposits compared to nanotubes bearing oxidized functions (-OH, -C=O, -C(=O)OH). Particular attention is also paid to the relative impact of the rate of functionalization and the dispersion degree of the carbon nanotubes in the coatings, as well as their wrapping level by the tantalum oxide matrix material. The resulting effect on the in vitro growth of hydroxyapatite is also evaluated to confirm the primary osseous bioactivity of those materials. Chemical, structural and morphological features of the different composite deposits described herein are assessed by X-ray photoelectron spectroscopy (XPS), scanning (SEM) and transmission (TEM) electronic microscopies, energy dispersive X-rays analysis (EDX) and peeling tests. Highlights: ► Formation of tantalum/carbon nanotube

  6. Sol–gel synthesis of tantalum oxide and phosphonic acid-modified carbon nanotubes composite coatings on titanium surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Maho, Anthony [Laboratory of Chemistry and Electrochemistry of Surfaces, University of Namur (FUNDP), Rue de Bruxelles 61, B-5000 Namur (Belgium); Fonds pour la Formation à la Recherche dans l' Industrie et dans l' Agriculture (FRIA), Rue d' Egmont 5, B-1000 Bruxelles (Belgium); Detriche, Simon; Delhalle, Joseph [Laboratory of Chemistry and Electrochemistry of Surfaces, University of Namur (FUNDP), Rue de Bruxelles 61, B-5000 Namur (Belgium); Mekhalif, Zineb, E-mail: zineb.mekhalif@fundp.ac.be [Laboratory of Chemistry and Electrochemistry of Surfaces, University of Namur (FUNDP), Rue de Bruxelles 61, B-5000 Namur (Belgium)

    2013-07-01

    Carbon nanotubes used as fillers in composite materials are more and more appreciated for the outstanding range of accessible properties and functionalities they generate in numerous domains of nanotechnologies. In the framework of biological and medical sciences, and particularly for orthopedic applications and devices (prostheses, implants, surgical instruments, …), titanium substrates covered by tantalum oxide/carbon nanotube composite coatings have proved to constitute interesting and successful platforms for the conception of solid and biocompatible biomaterials inducing the osseous regeneration processes (hydroxyapatite growth, osteoblasts attachment). This paper describes an original strategy for the conception of resistant and homogeneous tantalum oxide/carbon nanotubes layers on titanium through the introduction of carbon nanotubes functionalized by phosphonic acid moieties (-P(=O)(OH){sub 2}). Strong covalent C-P bonds are specifically inserted on their external sidewalls with a ratio of two phosphonic groups per anchoring point. Experimental results highlight the stronger “tantalum capture agent” effect of phosphonic-modified nanotubes during the sol–gel formation process of the deposits compared to nanotubes bearing oxidized functions (-OH, -C=O, -C(=O)OH). Particular attention is also paid to the relative impact of the rate of functionalization and the dispersion degree of the carbon nanotubes in the coatings, as well as their wrapping level by the tantalum oxide matrix material. The resulting effect on the in vitro growth of hydroxyapatite is also evaluated to confirm the primary osseous bioactivity of those materials. Chemical, structural and morphological features of the different composite deposits described herein are assessed by X-ray photoelectron spectroscopy (XPS), scanning (SEM) and transmission (TEM) electronic microscopies, energy dispersive X-rays analysis (EDX) and peeling tests. Highlights: ► Formation of tantalum

  7. Studies on the promotion of nickel—alumina coprecipitated catalysts: I. Titanium oxide

    NARCIS (Netherlands)

    Lansink Rotgerink, H.G.J.; Mercera, P.D.L.; van Ommen, J.G.; Ross, J.R.H.

    1988-01-01

    A series of TiO2-promoted nickel—alumina catalysts has been prepared and characterized. The promoter was added in various proportions to a calcined coprecipitated nickel—alumina material by adsorption of the acetylacetonate complex of titanium, followed by further calcination and reduction. The

  8. A deposit model for magmatic iron-titanium-oxide deposits related to Proterozoic massif anorthosite plutonic suites

    Science.gov (United States)

    Woodruff, Laurel G.; Nicholson, Suzanne W.; Fey, David L.

    2013-01-01

    This descriptive model for magmatic iron-titanium-oxide (Fe-Ti-oxide) deposits hosted by Proterozoic age massif-type anorthosite and related rock types presents their geological, mineralogical, geochemical, and geoenvironmental attributes. Although these Proterozoic rocks are found worldwide, the majority of known deposits are found within exposed rocks of the Grenville Province, stretching from southwestern United States through eastern Canada; its extension into Norway is termed the Rogaland Anorthosite Province. This type of Fe-Ti-oxide deposit dominated by ilmenite rarely contains more than 300 million tons of ore, with between 10- to 45-percent titanium dioxide (TiO2), 32- to 45-percent iron oxide (FeO), and less than 0.2-percent vanadium (V). The origin of these typically discordant ore deposits remains as enigmatic as the magmatic evolution of their host rocks. The deposits clearly have a magmatic origin, hosted by an age-constrained unique suite of rocks that likely are the consequence of a particular combination of tectonic circumstances, rather than any a priori temporal control. Principal ore minerals are ilmenite and hemo-ilmenite (ilmenite with extensive hematite exsolution lamellae); occurrences of titanomagnetite, magnetite, and apatite that are related to this deposit type are currently of less economic importance. Ore-mineral paragenesis is somewhat obscured by complicated solid solution and oxidation behavior within the Fe-Ti-oxide system. Anorthosite suites hosting these deposits require an extensive history of voluminous plagioclase crystallization to develop plagioclase-melt diapirs with entrained Fe-Ti-rich melt rising from the base of the lithosphere to mid- and upper-crustal levels. Timing and style of oxide mineralization are related to magmatic and dynamic evolution of these diapiric systems and to development and movement of oxide cumulates and related melts. Active mines have developed large open pits with extensive waste-rock piles, but

  9. Sealing glasses for titanium and titanium alloys

    Science.gov (United States)

    Brow, Richard K.; McCollister, Howard L.; Phifer, Carol C.; Day, Delbert E.

    1997-01-01

    Barium lanthanoborate sealing-glass compositions are provided comprising various combinations (in terms of mole-%) of boron oxide (B.sub.2 O.sub.3), barium oxide (BaO), lanthanum oxide (La.sub.2 O.sub.3), and at least one other oxide selected from the group consisting of aluminum oxide (Al.sub.2 O.sub.3), calcium oxide (CaO), lithium oxide (Li.sub.2 O), sodium oxide (Na.sub.2 O), silicon dioxide (SiO.sub.2), or titanium dioxide (TiO.sub.2). These sealing-glass compositions are useful for forming hermetic glass-to-metal seals with titanium and titanium alloys having an improved aqueous durability and favorable sealing characteristics. Examples of the sealing-glass compositions are provided having coefficients of thermal expansion about that of titanium or titanium alloys, and with sealing temperatures less than about 900.degree. C., and generally about 700.degree.-800.degree. C. The barium lanthanoborate sealing-glass compositions are useful for components and devices requiring prolonged exposure to moisture or water, and for implanted biomedical devices (e.g. batteries, pacemakers, defibrillators, pumps).

  10. Correlation of electrolyte-derived inclusions to crystallization in the early stage of anodic oxide film growth on titanium

    Energy Technology Data Exchange (ETDEWEB)

    Jaeggi, C., E-mail: christian.jaeggi@empa.ch [Empa, Swiss Federal Laboratories for Materials Testing and Research, Advanced Materials Processing Laboratory, Feuerwerkerstrasse 39, CH-3602 Thun (Switzerland); Parlinska-Wojtan, M., E-mail: magdalena.parlinska@empa.ch [Empa, Swiss Federal Laboratories for Materials Testing and Research, Center for Electron Microscopy, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland); Kern, P., E-mail: Philippe.Kern@neopac.ch [Empa, Swiss Federal Laboratories for Materials Testing and Research, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkerstrasse 39, CH-3602 Thun (Switzerland)

    2012-01-01

    Pure titanium has been subjected to anodization in sulfuric and phosphoric acid. For a better understanding of the oxide growth and properties of the final film, with a particular interest focused on the solution anions in the early stage of crystallization, microstructural analyses (Raman, Transmission Electron Microscopy [TEM]) of the oxide films were correlated to chemical depth profiling by glow discharge optical emission spectroscopy (GDOES). Raman spectroscopy shows that crystallization of the oxide films starts at potentials as low as 10-20 V. The onset of crystallization and the ongoing increase in crystallinity with increasing anodization potentials had already earlier been correlated to ac-impedance measurements [Jaeggi et al., Surf. Interface Anal. 38 (2006) 182]. TEM observations show a clear difference in the early phase of crystallization between oxides grown in 1 M sulfuric acid compared to 1 M phosphoric acid. Moreover, independent of electrolyte type, nano-sized pores from oxygen bubbles formation were revealed in the central part of the films. Until now, oxygen bubbles inside an anodically grown oxide have not been observed before without the presence of crystalline regions nearby. A growth model is proposed, in which the different starting locations of crystallization inside the films are correlated to the presence of the acid anions as residues in the film, as found by GDOES chemical depth-profiling.

  11. Disinfection of titanium dioxide nanotubes using super-oxidized water decrease bacterial viability without disrupting osteoblast behavior

    Energy Technology Data Exchange (ETDEWEB)

    Beltrán-Partida, Ernesto [Department of Biomaterials, Dental Materials and Tissue Engineering, Faculty of Dentistry Mexicali, Autonomous University of Baja California, Av. Zotoluca and Chinampas St., 21040 Mexicali, Baja California (Mexico); Department of Corrosion and Materials, Engineering Institute, Autonomous University of Baja California, Blvd. Benito Juarez and Normal St., 21280 Mexicali, Baja California (Mexico); Valdez-Salas, Benjamín, E-mail: benval@uabc.edu.mx [Department of Corrosion and Materials, Engineering Institute, Autonomous University of Baja California, Blvd. Benito Juarez and Normal St., 21280 Mexicali, Baja California (Mexico); Escamilla, Alan; Curiel, Mario [Department of Corrosion and Materials, Engineering Institute, Autonomous University of Baja California, Blvd. Benito Juarez and Normal St., 21280 Mexicali, Baja California (Mexico); Valdez-Salas, Ernesto [Ixchel Medical Centre, Av. Bravo y Obregón, 21000 Mexicali, Baja California (Mexico); Nedev, Nicola [Department of Corrosion and Materials, Engineering Institute, Autonomous University of Baja California, Blvd. Benito Juarez and Normal St., 21280 Mexicali, Baja California (Mexico); Bastidas, Jose M. [National Centre for Metallurgical Research, CSIC, Av. Gregorio del Amo 8, 28040 Madrid (Spain)

    2016-03-01

    Amorphous titanium dioxide (TiO{sub 2}) nanotubes (NTs) on Ti6Al4V alloy were synthesized by anodization using a commercially available super-oxidized water (SOW). The NT surfaces were sterilized by ultraviolet (UV) irradiation and disinfected using SOW. The adhesion and cellular morphology of pig periosteal osteoblast (PPO) cells and the behavior of Staphylococcus aureus (S. aureus) cultured on the sterilized and disinfected surfaces were investigated. A non-anodized Ti6Al4V disc sterilized by UV irradiation (without SOW) was used as control. The results of this study reveal that the adhesion, morphology and filopodia development of PPO cells in NTs are dramatically improved, suggesting that SOW cleaning may not disrupt the benefits obtained by NTs. Significantly decreased bacterial viability in NTs after cleaning with SOW and comparing with non-cleaned NTs was seen. The results suggest that UV and SOW could be a recommendable method for implant sterilization and disinfection without altering osteoblast behavior while decreasing bacterial viability. - Highlights: • The effect of super-oxidized water cleaning was studied on Ti6Al4V nanotubes. • Super oxidized-water cleaning caused a decline in S. aureus viability. • Osteoblast behavior was not disrupted after super-oxidized water disinfection. • Super-oxidized water is suggested as a cleaning protocol for TiO{sub 2} nanotubes.

  12. Disinfection of titanium dioxide nanotubes using super-oxidized water decrease bacterial viability without disrupting osteoblast behavior

    International Nuclear Information System (INIS)

    Beltrán-Partida, Ernesto; Valdez-Salas, Benjamín; Escamilla, Alan; Curiel, Mario; Valdez-Salas, Ernesto; Nedev, Nicola; Bastidas, Jose M.

    2016-01-01

    Amorphous titanium dioxide (TiO_2) nanotubes (NTs) on Ti6Al4V alloy were synthesized by anodization using a commercially available super-oxidized water (SOW). The NT surfaces were sterilized by ultraviolet (UV) irradiation and disinfected using SOW. The adhesion and cellular morphology of pig periosteal osteoblast (PPO) cells and the behavior of Staphylococcus aureus (S. aureus) cultured on the sterilized and disinfected surfaces were investigated. A non-anodized Ti6Al4V disc sterilized by UV irradiation (without SOW) was used as control. The results of this study reveal that the adhesion, morphology and filopodia development of PPO cells in NTs are dramatically improved, suggesting that SOW cleaning may not disrupt the benefits obtained by NTs. Significantly decreased bacterial viability in NTs after cleaning with SOW and comparing with non-cleaned NTs was seen. The results suggest that UV and SOW could be a recommendable method for implant sterilization and disinfection without altering osteoblast behavior while decreasing bacterial viability. - Highlights: • The effect of super-oxidized water cleaning was studied on Ti6Al4V nanotubes. • Super oxidized-water cleaning caused a decline in S. aureus viability. • Osteoblast behavior was not disrupted after super-oxidized water disinfection. • Super-oxidized water is suggested as a cleaning protocol for TiO_2 nanotubes.

  13. Fabrication of ceramic oxide-coated SWNT composites by sol-gel process with a polymer glue

    Science.gov (United States)

    Zhang, Cheng; Gao, Lei; Chen, Yongming

    2011-09-01

    The functional copolymer bearing alkoxysilyl and pyrene groups, poly[3-(triethoxysilyl)propyl methacrylate]- co-[(1-pyrene-methyl) methacrylate] (TEPM13- co-PyMMA3), was synthesized via atom transfer radical polymerization. Attributing the π-π interaction of pyrene units with the walls of single-walled carbon nanotubes (SWNTs), this polymer could disperse and exfoliate SWNTs in different solvents through physical interaction as demonstrated by TEM, UV/Vis absorption, and FT-IR analysis. The alkoxysilyl groups functionalized SWNTs were reacted with different inorganic precursors via sol-gel reaction, and, as a results, silica, titania, and alumina were coated onto the surface of SWNTs, respectively via copolymers as a molecular glue. The nanocomposites of ceramic oxides/SWNTs were characterized by SEM analysis. Dependent upon the feed, the thickness of inorganic coating can be tuned easily. This study supplies a facile and general way to coat SWNTs with ceramic oxides without deteriorating the properties of pristine SWNTs.

  14. Brazing of zirconia to titanium using Ag-Cu and Au-Ni filler alloys

    Directory of Open Access Journals (Sweden)

    Jean S. Pimenta

    2013-12-01

    Full Text Available Advanced ceramic is usually joined to metal by the well-known direct brazing process, where costly active filler alloys can be considered a limitation. Brazing using active-metal-free filler alloy as insert between the joint components is an attempt to overcome it. The active metal diffusion from the titanium member through the bulk of molten filler to the ceramic was responsible to produce an active filler alloy in loco and promote reduction of the zirconium oxide to improve wetting on the ceramic surface. Unalloyed titanium was joined in a high-vacuum furnace (<3x10-5 mbar to yttria-tetragonal zirconia polycristals (Y-TZP and zirconia partially stabilized with magnesia (Mg-PSZ, where commercial fillers Ag-28Cu and Au-18Ni with respective thermal cycles were evaluated. Helium gas leak detection test was performed at the ceramic/metal interface at room temperature; samples from reliable vacuum tight joints were examined by microstructural analysis techniques and energy dispersive X-ray analysis at the joint cross-section. Tight joints were produced with eutectic Ag-Cu filler, revealing an intermetallic layer and a dark reaction layer near the ceramic surface; titanium diffusion was efficient for superficial chemical interactions between individual components. Brazing joints were also tested using three-point flexure testing.

  15. Electrochemical promotion of propane oxidation on Pt deposited on a dense β"-Al2O3 ceramic Ag+ conductor

    Directory of Open Access Journals (Sweden)

    Michail eTsampas

    2013-08-01

    Full Text Available A new kind of electrochemical catalyst based on a Pt porous catalyst film deposited on a β"-Al2O3 ceramic Ag+ conductor was developed and evaluated during propane oxidation. It was observed that upon anodic polarization, the rate of propane combustion was significantly electropromoted up to 400%. Moreover, for the first time, exponential increase of the catalytic rate was evidenced during galvanostatic transient experiment in excellent agreement with EPOC equation.

  16. The behavior of SiC and Si3N4 ceramics in mixed oxidation/chlorination environments

    Science.gov (United States)

    Marra, John E.; Kreidler, Eric R.; Jacobson, Nathan S.; Fox, Dennis S.

    1989-01-01

    The behavior of silicon-based ceramics in mixed oxidation/chlorination environments was studied. High pressure mass spectrometry was used to quantitatively identify the reaction products. The quantitative identification of the corrosion products was coupled with thermogravimetric analysis and thermodynamic equilibrium calculations run under similar conditions in order to deduce the mechanism of corrosion. Variations in the behavior of the different silicon-based materials are discussed. Direct evidence of the existence of silicon oxychloride compounds is presented.

  17. Method for improving the performance of oxidizable ceramic materials in oxidizing environments

    Science.gov (United States)

    Nagaraj, Bangalore A. (Inventor)

    2002-01-01

    Improved adhesion of thermal barrier coatings to nonmetallic substrates using a dense layer of ceramic on an underlying nonmetallic substrate that includes at least one oxidizable component. The improved adhesion occurs because the application of the dense ceramic layer forms a diffusion barrier for oxygen. This diffusion barrier prevents the oxidizable component of the substrate from decomposing. The present invention applies ceramic by a process that deposits a relatively thick and dense ceramic layer on the underlying substrate. The formation of the dense layer of ceramic avoids the problem of void formation associated with ceramic formation by most prior art thermal decomposition processes. The formation of voids has been associated with premature spalling of thermal barrier layers and other protective layers applied to substrates.

  18. Effect of oxidation at elevated temperature on elastic and interface properties of ceramic matrix composites

    Czech Academy of Sciences Publication Activity Database

    Brandstetter, J.; Glogar, Petr; Loidl, D.; Kromp, K.

    2005-01-01

    Roč. 290, - (2005), s. 340-343 ISSN 1013-9826. [International conference on fractography of advanced ceramics /2./. Stará Lesná, 03.10.2005-06.10.2005] R&D Projects: GA AV ČR(CZ) KSK2067107 Institutional research plan: CEZ:AV0Z30460519 Keywords : polysiloxane * ceramic matrix composite * shear modulus Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 0.224, year: 2005

  19. Combinatorial Production and Processing of Oxide Nanopowders for Transparent, Ceramic Lasers

    National Research Council Canada - National Science Library

    Laine, Richard M; Rand, Stephen C

    2007-01-01

    Since the discovery of transparent polycrystalline alumina by Coble in 1962, transparent and translucent alumina and yttria based ceramics have achieved a significant presence in our everyday lives...

  20. Nitroxide-Mediated Radical Polymerization of Styrene Initiated from the Surface of Titanium Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    M. Abbasian

    2016-01-01

    Full Text Available Titanium dioxide (TiO2 nanoparticles, with an average size of about 45 nm, were encapsulated by polystyrene using in situ nitroxide mediated radical polymerization   in the presence of 3-aminopropyl triethoxy silane (APTES as a coupling agent and 2, 2, 6, 6-tetramethylpiperidinyl-1-oxy  as a initiator. First, the initiator for NMRP was covalently bonded onto the surface of Titanium dioxide nanoparticles through our novel method. For this purpose, the surface of TiO2 nanoparticle was treated with 3-aminopropyl triethoxy silane, a silane coupling agent, and then these functionalized nanoparticles was reacted with ±-chloro phenyl acetyl chloride. The chlorine groups were converted to nitroxide mediated groups by coupling with 1-hydroxy-2, 2, 6, 6-tetramethyl piperidine. These modified TiO2 nanoparticles were then dispersed in styrene (St monomers to carry out the in situ free radical polymerization.

  1. Titanium di-oxide films using a less hygroscopic colloidal precursor

    Energy Technology Data Exchange (ETDEWEB)

    Vandana,, E-mail: vandana1@nplindia.org; Batra, Neha; Kumar, Praveen; Sharma, Pooja; Singh, P.K., E-mail: pksingh@nplindia.org

    2014-04-01

    We report the study of titanium dioxide films (TiO{sub 2}) using titanium di-isopropoxyl di-2ethyl hexanoate Ti(OC{sub 3}H{sub 7}){sub 2} (C{sub 7}H{sub 15}COO){sub 2} colloidal precursor. This compound is less hygroscopic in nature and easy to use with processes like spin or dip coating. Thin films of TiO{sub 2} are made on silicon substrates and their structural and optical properties are studied. The effect of Ti content in the precursor, sintering temperature and its duration on film thickness and refractive index are investigated. Refractive index shows an increasing trend with the rise in the sintering temperature but remains unchanged with the time. The film thickness decreases with both sintering temperature and time and increases with Ti content in the precursor. Reflectivity measurements show marked reduction in the reflection losses compared to bare silicon surface wherein the film thickness is altered by spin speed. XRD results show anatase phase in the samples sintered at lower temperature (<680 °C), however, a mix of anatase, brookite and rutile phases is seen above this temperature. In the samples sintered above 1100 °C, rutile phase is dominant. These results are supported by the X-ray photoelectron spectroscopy. Atomic force microscopy reveals larger grain size at higher sintering temperature. The titanium dioxide films of desirable thickness and refractive index could be used as an antireflection coating on solar cells. - Highlights: • TiO{sub 2} films are made using titanium di-isopropoxyl di-2ethyl hexanoate precursor. • Effect of Ti content in the precursor, sintering temperature and time is studied. • Refractive index (μ) increases with sintering temperature but is independent of time. • Films of desired thickness and μ could be used as an antireflection coating. • XRD results show that rutile phase dominates in samples sintered above 1100 °C.

  2. Changes in the structural and electrical properties of vacuum post-annealed tungsten- and titanium-doped indium oxide films deposited by radio frequency magnetron sputtering

    NARCIS (Netherlands)

    Yan, L.T.; Schropp, R.E.I.

    2011-01-01

    Tungsten- and titanium-doped indium oxide (IWO and ITiO) filmswere deposited at room temperature by radio frequency (RF) magnetron sputtering, and vacuum post-annealing was used to improve the electron mobility. With increasing deposition power, the as deposited films showed an increasingly

  3. Study of the rheological properties of casting slips obtained from titanium oxide and bariun titanate in order to obtain pieces by means of casting in plaster moulds

    International Nuclear Information System (INIS)

    Amarante Junior, A.

    1986-01-01

    The behaviour of titanium-oxide (TiO 2 ) and barium titanate used in slip casting with plaster moulds is studied. Some data in several tests, as well as materials and methods applied are presented. (M.J.C.) [pt

  4. The Interface Structure of High-Temperature Oxidation-Resistant Aluminum-Based Coatings on Titanium Billet Surface

    Science.gov (United States)

    Xu, Zhefeng; Rong, Ju; Yu, Xiaohua; Kun, Meng; Zhan, Zhaolin; Wang, Xiao; Zhang, Yannan

    2017-10-01

    A new type of high-temperature oxidation-resistant aluminum-based coating, on a titanium billet surface, was fabricated by the cold spray method, at a high temperature of 1050°C, for 8 h, under atmospheric pressure. The microstructure of the exposed surface was analyzed via optical microscopy, the microstructure of the coating and elemental diffusion was analyzed via field emission scanning electron microscopy, and the interfacial phases were identified via x-ray diffraction. The Ti-Al binary phase diagram and Gibbs free energy of the stable phase were calculated by Thermo-calc. The results revealed that good oxidation resistant 50-μm-thick coatings were successfully obtained after 8 h at 1050°C. Two layers were obtained after the coating process: an Al2O3 oxidation layer and a TiAl3 transition layer on the Ti-based substrate. The large and brittle Al2O3 grains on the surface, which can be easily spalled off from the surface after thermal processing, protected the substrate against oxidation during processing. In addition, the thermodynamic calculation results were in good agreement with the experimental data.

  5. Hydrogen absorption of titanium for nuclear waste container in non-oxidizing condition

    International Nuclear Information System (INIS)

    Tomari, H.; Masugata, T.; Shimogori, K.; Nishimura, T.; Wada, R.; Honda, A.; Taniguchi, N.

    1999-10-01

    Effects of bentonite clay, applied potential, pH, of solution and cathodic polarization time on hydrogen absorption into titanium, which is one of the candidate materials of overpack for high-level radioactive waste container, have been investigated in artificial underground water. Considering the result at various test time and assuming the hydrogen absorption is ruled by the parabolic law, the amount of hydrogen after 1000 years exposure calculated to about 17ppm, which will be absorbed at the applied potential if -0.51 vs. SHE corresponds to equilibrium potential of hydrogen. It seems the assumption of the parabolic law and the test period are proper, because the linear relations were obtained between the amount of absorbed hydrogen and the logarithm of the averaged cathodic current and between the slopes of the lines and a square root of the test time. Titanium seems to have a life over 1000 years in deep underground repository according to assumption that about 500ppm absorbed hydrogen is critical for hydrogen embrittlement of titanium. (author)

  6. Development of a Fabrication Process Using Suspension Plasma Spray for Titanium Oxide Photovoltaic Device

    Directory of Open Access Journals (Sweden)

    Hsian Sagr Hadi A

    2017-03-01

    Full Text Available In order to reduce the high costs of conventional materials, and to reduce the power necessary for the deposition of titanium dioxide, titanium tetrabutoxide has been developed in the form of a suspension of TiO2 using water instead of expensive ethanol. To avoid sedimentation of hydroxide particles in the suspension, mechanical milling of the suspension was conducted in order to create diffusion in colloidal suspension before using it as feedstock. Consequently, through the creation of a colloidal suspension, coating deposition was able to be conducted without sedimentation of the hydroxide particles in the suspension during the deposition process. Though an amorphous as-deposited coating was able to be deposited, through post heat treatment at 630 °C for 60 min, the chemical structure became anatase rich. In addition, it was confirmed that the post heat treated anatase rich coating had enough photo-catalytic activity to decolor methylene-blue droplets. From these results, this technique was found to have high potential in the low cost photo-catalytic titanium coating production process.

  7. Ultra-hard ceramic coatings fabricated through microarc oxidation on aluminium alloy

    International Nuclear Information System (INIS)

    Wu Hanhua; Wang Jianbo; Long Beiyu; Long Beihong; Jin Zengsun; Naidan Wang; Yu Fengrong; Bi Dongmei

    2005-01-01

    Ultra-hard ceramic coatings with microhardness of 2535 Hv have been synthesized on the Al alloy substrate by microarc oxidation (MAO) technique. The effects of anodic current density (j a ) and the ratio of cathodic to anodic current density (j c /j a ) on the mechanical and corrosion resistance properties of MAO coatings have been studied by microhardness and pitting corrosion tests, respectively. In addition, the phase composition and microstructure of the coatings were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The results show that the coatings prepared at high anodic current density consist mainly of α-Al 2 O 3 , while those fabricated at low anodic current density are almost composed of γ-Al 2 O 3 . Microhardness test shows that the coatings have high microhardness, and the highest one is found in the coating formed at j a = 15 A/dm 2 and j c /j a = 0.7. Pitting corrosion test shows that the structure of coatings is strongly influenced by the varying j c /j a

  8. Thermoelectric Properties of the Yttrium-Doped Ceramic Oxide SrTiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Tamal Tahsin; Ur, Soon-Chul [Korea National University of Transportation, Chungju (Korea, Republic of)

    2017-01-15

    The doping dependence of the thermoelectric figure of merit, ZT, of the ceramic oxide SrTiO{sub 3} at high temperature has been studied. In this study, yttrium was used as the doping element. A conventional solid-state reaction method was used for the preparation of Y-doped SrTiO{sub 3}. The doping level in SrTiO{sub 3} was controlled to be in the doping range of 2 - 10 mole%. Almost all the yttrium atoms incorporated into the SrTiO{sub 3} provided charge carriers, as was observed by using X-ray diffraction pattern. The relative densities of all the samples varied from 98.53% to 99.45%. The thermoelectric properties, including the electrical conductivity σ, Seebeck coefficient S, thermal conductivity k, and the figure of merit, ZT, were investigated at medium temperatures. The ZT value showed an obvious doping level dependence, in which a value as high as 0.18 is realized at 773 K for a doping of 8 mole%.

  9. Investigation of thermal conductivity and oxidation behaviour of reaction bonded aluminum nitride (RBAN) ceramics

    International Nuclear Information System (INIS)

    Salahi, E; Moztarzadeh, F.; Margoosian, V.; Heinrich, J. G.

    2003-01-01

    AlN samples have been produced by reaction bonding process using AlN and aluminum powders as starting materials. Different aluminum nitride and aluminum powders ratios were mixed in ethanol media, dried, isostatically and nitrided in (N 2 )atmosphere. Results showed that conversion of to AlN depends strongly on the amount of aluminum starting powder and decreased with increasing after a maximum at 25 Al wt %. Changing the particle size and morphology of the aluminum starting powder leads to change in the conversion ratio and microstructure of RBAN ceramics. Typical scanning electron micrographs of RBAN sample indicating primary and secondary aluminum nitride morphology and pore structure. The oxidation behavior of RABN samples showed the weight gain depends on the average particle size, morphology and amount of Al in starting mixture and pore structure. Samples have been manufactured with equi-axed morphology of Al starting powder have thermal conductivity higher than the samples have been manufactured with flake-like morphology. These differences were directly related to the different microstructure of RBAN samples

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

    Science.gov (United States)

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

    2011-10-01

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

  11. Droplet size prediction in ultrasonic nebulization for non-oxide ceramic powder synthesis.

    Science.gov (United States)

    Muñoz, Mariana; Goutier, Simon; Foucaud, Sylvie; Mariaux, Gilles; Poirier, Thierry

    2018-03-01

    Spray pyrolysis process has been used for the synthesis of non-oxide ceramic powders from liquid precursors in the Si/C/N system. Particles with a high thermal stability and with variable composition and size distribution have been obtained. In this process, the mechanisms involved in precursor decomposition and gas phase recombination of species are still unknown. The final aim of this work consists in improving the whole process comprehension by an experimental/modelling approach that helps to connect the synthesized particles characteristics to the precursor properties and process operating parameters. It includes the following steps: aerosol formation by a piezoelectric nebulizer, its transport and the chemical-physical phenomena involved in the reaction processes. This paper focuses on the aerosol characterization to understand the relationship between the liquid precursor properties and the liquid droplet diameter distribution. Liquids with properties close to the precursor of interest (hexamethyldisilazane) have been used. Experiments have been performed using a shadowgraphy technique to determine the drop size distribution of the aerosol. For all operating parameters of the nebulizer device and liquids used, bimodal droplet size distributions have been obtained. Correlations proposed in the literature for the droplet size prediction by ultrasonic nebulization were used and adapted to the specific nebulizer device used in this study, showing rather good agreement with experimental values. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Surface oxidation of porous ZrB{sub 2}-SiC ceramic composites by continuous-wave ytterbium fibre laser

    Energy Technology Data Exchange (ETDEWEB)

    Mahmod, Dayang Salyani Abang, E-mail: dygsalyani@gmail.com [Department of Mechanical and Manufacturing Engineering, Faculty of Engineering, Universiti Malaysia Sarawak, 94300 Kota Samarahan, Sarawak (Malaysia); Glandut, Nicolas [SPCTS, UMR 7315, CNRS, University of Limoges, European Ceramic Center, 12 Rue Atlantis, 87068 Limoges (France); Khan, Amir Azam [Department of Mechanical and Manufacturing Engineering, Faculty of Engineering, Universiti Malaysia Sarawak, 94300 Kota Samarahan, Sarawak (Malaysia); Labbe, Jean-Claude [SPCTS, UMR 7315, CNRS, University of Limoges, European Ceramic Center, 12 Rue Atlantis, 87068 Limoges (France)

    2015-12-01

    Highlights: • Surface oxidation of ZrB{sub 2}-SiC ceramic composites by Yb-fibre laser. • Round spiral laser pattern created for the surface oxidation. • Presence of laser-formed oxide scale and unaffected beneath regions. • Crazed but uncracked surface oxide. • A dense glassy SiO{sub 2}-rich layer exhibited enhances oxidation resistance. - Abstract: Surface treatment of ceramic substrates by a laser beam can allow to incorporate interesting properties to these ceramics. In the present work, surface oxidation of ca. 30% porous ZrB{sub 2}-SiC ceramic composites by using an ytterbium fibre laser was conducted. Oxidation of ceramic substrates through this process under ambient conditions has certain advantages compared to the classical oxidation method. A particular spiral laser pattern was created in order to produce an oxidized structure on ZrB{sub 2}-SiC porous substrates. The laser parameters were as follows i.e., laser power of 50, 60 and 70 W, a beam diameter of 1.25 mm, velocity of 2 mm/s, acceleration and deceleration of 1 mm/s{sup 2}. The microstructural and morphological changes in the laser-treated region was examined using scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. At laser power of 70 W, the sample exhibits uniform oxidation. It revealed that the very porous bulk beneath remained unaffected and unoxidized because this laser-formed oxide scale protects the substrate from oxidation. The presence of oxidized and unaffected regions indicated a high degree of heat localization. The dense glassy SiO{sub 2}-rich layer prevents the inward oxygen diffusion into the inner bulk hence enhances the oxidation resistance.

  13. A deposit model for magmatic iron-titanium-oxide deposits related to Proterozoic massif anorthosite plutonic suites: Chapter K in Mineral Deposit Models for Resource Assessment

    Science.gov (United States)

    Woodruff, Laurel G.; Nicholson, Suzanne W.; Fey, David L.

    2013-01-01

    This descriptive model for magmatic iron-titanium-oxide (Fe-Ti-oxide) deposits hosted by Proterozoic age massif-type anorthosite and related rock types presents their geological, mineralogical, geochemical, and geoenvironmental attributes. Although these Proterozoic rocks are found worldwide, the majority of known deposits are found within exposed rocks of the Grenville Province, stretching from southwestern United States through eastern Canada; its extension into Norway is termed the Rogaland Anorthosite Province. This type of Fe-Ti-oxide deposit dominated by ilmenite rarely contains more than 300 million tons of ore, with between 10- to 45-percent titanium dioxide (TiO2), 32- to 45-percent iron oxide (FeO), and less than 0.2-percent vanadium (V).

  14. Exposure to nano-size titanium dioxide causes oxidative damages in human mesothelial cells: The crystal form rather than size of particle contributes to cytotoxicity.

    Science.gov (United States)

    Hattori, Kenji; Nakadate, Kazuhiko; Morii, Akane; Noguchi, Takumi; Ogasawara, Yuki; Ishii, Kazuyuki

    2017-10-14

    Exposure to nanoparticles such as carbon nanotubes has been shown to cause pleural mesothelioma similar to that caused by asbestos, and has become an environmental health issue. Not only is the percutaneous absorption of nano-size titanium dioxide particles frequently considered problematic, but the possibility of absorption into the body through the pulmonary route is also a concern. Nevertheless, there are few reports of nano-size titanium dioxide particles on respiratory organ exposure and dynamics or on the mechanism of toxicity. In this study, we focused on the morphology as well as the size of titanium dioxide particles. In comparing the effects between nano-size anatase and rutile titanium dioxide on human-derived pleural mesothelial cells, the anatase form was shown to be actively absorbed into cells, producing reactive oxygen species and causing oxidative damage to DNA. In contrast, we showed for the first time that the rutile form is not easily absorbed by cells and, therefore, does not cause oxidative DNA damage and is significantly less damaging to cells. These results suggest that with respect to the toxicity of titanium dioxide particles on human-derived mesothelial cells, the crystal form rather than the particle size has a greater effect on cellular absorption. Also, it was indicated that the difference in absorption is the primary cause of the difference in the toxicity against mesothelial cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. 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.

  16. Study for preparation of nanoporous titania on titanium by anodic oxidation; Estudo da preparacao de titania nanoporosa sobre titanio por oxidacao anodica

    Energy Technology Data Exchange (ETDEWEB)

    Passos, Alessandra Pires

    2014-07-01

    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{sub 3}PO{sub 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{sub 2}. The results obtained in this study

  17. Method of sintering ceramic materials

    Science.gov (United States)

    Holcombe, Cressie E.; Dykes, Norman L.

    1992-01-01

    A method for sintering ceramic materials is described. A ceramic article is coated with layers of protective coatings such as boron nitride, graphite foil, and niobium. The coated ceramic article is embedded in a container containing refractory metal oxide granules and placed within a microwave oven. The ceramic article is heated by microwave energy to a temperature sufficient to sinter the ceramic article to form a densified ceramic article having a density equal to or greater than 90% of theoretical density.

  18. Physicochemical properties and in vitro cytocompatibility of modified titanium surfaces prepared via micro-arc oxidation with different calcium concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Sui-Dan; Zhang, Hui [Guanghua School of Stomatology, Hospital of Stomatology, Guangdong Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China); Dong, Xu-Dong [Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC V6T 1Z3 (Canada); Ning, Cheng-Yun [College of Material Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Fok, Alex S.L. [Minnesota Dental Research Center of Biomaterials and Biomechanics, School of Dentistry, University of Minnesota, Minneapolis, MN 55414 (United States); Wang, Yan, E-mail: wyan65@163.com [Guanghua School of Stomatology, Hospital of Stomatology, Guangdong Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China)

    2015-02-28

    Highlights: • MAO coating improves the surface characteristics and cytocompatibility of titanium. • Composition of MAO coating varies with the electrolyte concentration. • MAO coating properties can be optimized by adjusting the electrolyte concentration. • Higher CA concentration contributes to more favorable MAO coating cytocompatibility. - Abstract: Objective: To explore the effect of calcium concentration in the electrolyte solution on the physicochemical properties and biocompatibility of coatings formed by micro-arc oxidation (MAO) on titanium surfaces. Methods: The surfaces of pure titanium plates were modified by MAO in an electrolytic solution containing calcium acetate (CA; C{sub 4}H{sub 6}CaO{sub 4}) at concentrations of 0.05, 0.1, 0.2, or 0.3 M and β-glycerophosphate disodium salt pentahydrate (β-GP; C{sub 3}H{sub 7}Na{sub 2}O{sub 6}P·5H{sub 2}O) at a fixed concentration of 0.02 M. Surface topography, elemental characteristics, phase composition, and roughness were investigated by scanning electron microscopy, energy-dispersive X-ray analysis, X-ray diffraction, and a surface roughness tester, respectively. To assess the cytocompatibility and osteoinductivity of the surfaces, MC3T3-E1 preosteoblasts were cultured on the surfaces in vitro, and cell morphology, adhesion, proliferation, and differentiation were observed. Results: The porous MAO coating was composed primarily of TiO{sub 2} rutile and anatase. The amount of TiO{sub 2} rutile, the Ca/P ratio, and the surface roughness of the MAO coating increased with increasing CA concentration in the electrolyte solution. Ca{sub 3}(PO{sub 4}){sub 2}, CaCO{sub 3}, and CaTiO{sub 3} were formed on MAO-treated surfaces prepared with CA concentrations of 0.2 and 0.3 M. Cell proliferation and differentiation increased with increasing CA concentration, with MC3T3-E1 cells exhibiting favorable morphologies for bone–implant integration. Conclusions: MAO coating improves the surface characteristics and

  19. Physicochemical properties and in vitro cytocompatibility of modified titanium surfaces prepared via micro-arc oxidation with different calcium concentrations

    International Nuclear Information System (INIS)

    Wu, Sui-Dan; Zhang, Hui; Dong, Xu-Dong; Ning, Cheng-Yun; Fok, Alex S.L.; Wang, Yan

    2015-01-01

    Highlights: • MAO coating improves the surface characteristics and cytocompatibility of titanium. • Composition of MAO coating varies with the electrolyte concentration. • MAO coating properties can be optimized by adjusting the electrolyte concentration. • Higher CA concentration contributes to more favorable MAO coating cytocompatibility. - Abstract: Objective: To explore the effect of calcium concentration in the electrolyte solution on the physicochemical properties and biocompatibility of coatings formed by micro-arc oxidation (MAO) on titanium surfaces. Methods: The surfaces of pure titanium plates were modified by MAO in an electrolytic solution containing calcium acetate (CA; C 4 H 6 CaO 4 ) at concentrations of 0.05, 0.1, 0.2, or 0.3 M and β-glycerophosphate disodium salt pentahydrate (β-GP; C 3 H 7 Na 2 O 6 P·5H 2 O) at a fixed concentration of 0.02 M. Surface topography, elemental characteristics, phase composition, and roughness were investigated by scanning electron microscopy, energy-dispersive X-ray analysis, X-ray diffraction, and a surface roughness tester, respectively. To assess the cytocompatibility and osteoinductivity of the surfaces, MC3T3-E1 preosteoblasts were cultured on the surfaces in vitro, and cell morphology, adhesion, proliferation, and differentiation were observed. Results: The porous MAO coating was composed primarily of TiO 2 rutile and anatase. The amount of TiO 2 rutile, the Ca/P ratio, and the surface roughness of the MAO coating increased with increasing CA concentration in the electrolyte solution. Ca 3 (PO 4 ) 2 , CaCO 3 , and CaTiO 3 were formed on MAO-treated surfaces prepared with CA concentrations of 0.2 and 0.3 M. Cell proliferation and differentiation increased with increasing CA concentration, with MC3T3-E1 cells exhibiting favorable morphologies for bone–implant integration. Conclusions: MAO coating improves the surface characteristics and cytocompatibility of titanium for osseointegration. Higher CA

  20. Fatigue limit of polycrystalline zirconium oxide ceramics: effect of grinding and low-temperature aging

    NARCIS (Netherlands)

    Pereira, G.K.R.; Silvestri, T.; Amaral, M.; Rippe, M.P.; Kleverlaan, C.J.; Valandro, L.F.

    2016-01-01

    The following study aimed to evaluate the effect of grinding and low-temperature aging on the fatigue limit of Y-TZP ceramics for frameworks and monolithic restorations. Disc specimens from each ceramic material, Lava Frame (3M ESPE) and Zirlux FC (Ivoclar Vivadent) were manufactured according to

  1. Microstructure and performance of titanium oxide coatings sprayed by oxygen-acetylene flame

    Czech Academy of Sciences Publication Activity Database

    Ctibor, Pavel; Štengl, Václav; Zahálka, F.; Murafa, Nataliya

    2011-01-01

    Roč. 10, č. 3 (2011), s. 403-407 ISSN 1474-905X R&D Projects: GA AV ČR IAAX00430803 Institutional research plan: CEZ:AV0Z20430508; CEZ:AV0Z40320502 Keywords : Plasma spraying * flame spraying * photocatalysis * TiO2 Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 2.584, year: 2011

  2. Air purification by heterogeneous photocatalytic oxidation with multi-doped thin film titanium dioxide

    Energy Technology Data Exchange (ETDEWEB)

    O' Keeffe, Cormac, E-mail: cormac.okeeffe@theta.ie [Theta Chemicals Ltd., Station Road, Ballindine, Claremorris, Mayo (Ireland); Gannon, Paul; Gilson, Paul [Theta Chemicals Ltd., Station Road, Ballindine, Claremorris, Mayo (Ireland); Kafizas, Andreas; Parkin, Ivan P. [Department of Chemistry, University College London, Christopher Ingold Laboratories, 20 Gordon Street, London WC1H 0AJ (United Kingdom); Binions, Russell [School of Engineering and Materials Sciences, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom)

    2013-06-30

    Multi element-doped titania films (F, S-TiO{sub 2}) were produced via sol–gel techniques and deposited on glass and ceramic substrates with an annealing temperature of 500 °C. The films were characterised by X-ray diffraction, Raman Spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy. The X-ray diffraction and Raman spectrum showed the films to have an anatase TiO{sub 2} structure with X-ray photoelectron spectroscopy confirming the presence of sulphur, fluorine and carbon doping. The titania coated glass and ceramic substrates were compared against two commercially available TiO{sub 2} coated products for the photo-destruction of NO{sub 2(g)}. The study included both equivalent indoor and outdoor test conditions. The multi-doped titania films were shown to provide a genuine method of air purification under both visible (room lighting) and UVA lighting with photo-destruction rates as high as 72%. - Highlights: • Synthesis of multi-doped titania films • Excellent NO{sub 2} conversion rates for coated ceramic tiles • Excellent NO{sub 2} conversion rates for coated glass substrates • Significantly better conversion rates for existing commercial products.

  3. Optimization of the injection molding process for development of high performance calcium oxide -based ceramic cores

    Science.gov (United States)

    Zhou, P. P.; Wu, G. Q.; Tao, Y.; Cheng, X.; Zhao, J. Q.; Nan, H.

    2018-02-01

    The binder composition used for ceramic injection molding plays a crucial role on the final properties of sintered ceramic and to avoid defects on green parts. In this study, the effects of binder compositions on the rheological, microstructures and the mechanical properties of CaO based ceramic cores were investigated. It was found that the optimized formulation for dispersant, solid loading was 1.5 wt% and 84 wt%, respectively. The microstructures, such as porosity, pore size distribution and grain boundary density were closely related to the plasticizer contents. The decrease of plasticizer contents can enhance the strength of the ceramic cores but with decreased shrinkage. Meanwhile, the creep resistance of ceramic cores was enhanced by decreasing of plasticizer contents. The flexural strength of the core was found to decrease with the increase of the porosity, the improvement of creep resistance is closely related to the decrease of porosity and grain boundary density.

  4. Removal of aluminum(III)-based turbidity in water using hydrous titanium oxide dispersed in ion-exchange resins

    International Nuclear Information System (INIS)

    Venkataramani, B.; Karweer, S.B.; Iyer, R.K.; Phatak, G.M.; Iyer, R.M.

    1988-01-01

    An adsorber consisting of hydrous titanium oxide (HTiO) dispersed in a Dowex-type ion-exchange resin matrix (designated RT resins) has been developed which is capable of removing Al(III)-based colloidal dispersions in the neutral pH condition. The effect of resin crosslinking, particle size, HTiO loading, turbidity level, and flow rate on the turbidity removal efficiency of RT resins has been studied. It is demonstrated that a train of columns comprising RT resin, H + , and OH - form of resins could be used for large-scale purification operations at high flow rates. These columns, apart from removing turbidity and associated radioactivity, can effectively remove dissolved uranium present in ppb levels when used for water purification in nuclear reactors

  5. Combination of maghemite and titanium oxide nanoparticles in polyvinyl alcohol-alginate encapsulated beads for cadmium ions removal

    Energy Technology Data Exchange (ETDEWEB)

    Majidnia, Zohreh; Idris, Ani [Universiti Teknologi Malaysia, johor bahru (Malaysia)

    2015-06-15

    Both maghemite (γ-Fe{sub 2}O{sub 3}) and titanium oxide (TiO{sub 2}) nanoparticles were mixed at various ratios and embedded in polyvinyl alcohol (PVA)-alginate beads. These beads were tested for photocatalytic behavior in eliminating toxic Cd(Ⅱ) from the aqueous solution. The photocatalytic experiments were performed under sunlight irradiation at various pH, initial feed concentrations and γ-Fe{sub 2}O{sub 3}: TiO{sub 2} ratios. The recycling attribute of these beads was also investigated. The results revealed that 100% of the Cd(Ⅱ) was eliminated in 150 minutes at pH 7 under sunlight. It shows that maghemite and titania PVA-alginate beads can be readily isolated from the aqueous solution after the photocatalyst process and reused for at least six times without losing their initial properties.

  6. Oxygen Partial Pressure Impact on Characteristics of Indium Titanium Zinc Oxide Thin Film Transistor Fabricated via RF Sputtering.

    Science.gov (United States)

    Hsu, Ming-Hung; Chang, Sheng-Po; Chang, Shoou-Jinn; Wu, Wei-Ting; Li, Jyun-Yi

    2017-06-26

    Indium titanium zinc oxide (InTiZnO) as the channel layer in thin film transistor (TFT) grown by RF sputtering system is proposed in this work. Optical and electrical properties were investigated. By changing the oxygen flow ratio, we can suppress excess and undesirable oxygen-related defects to some extent, making it possible to fabricate the optimized device. XPS patterns for O 1s of InTiZnO thin films indicated that the amount of oxygen vacancy was apparently declined with the increasing oxygen flow ratio. The fabricated TFTs showed a threshold voltage of -0.9 V, mobility of 0.884 cm²/Vs, on-off ratio of 5.5 × 10⁵, and subthreshold swing of 0.41 V/dec.

  7. Titanium dioxide use (TiO2) in cement matrix as a photocatalyst of nitrogen oxides (NOx)

    International Nuclear Information System (INIS)

    Casagrande, C.A.; Hotza, D.; Repette, W.L.; Jochem, L.F.

    2012-01-01

    The use of titanium dioxide (TiO 2 ) in the photodegradation of nitrogen oxides (NO x ) is a technology that can contribute against to environmental pollution. This work shows the feasibility of using TiO 2 in mortars for photocatalysis. The Degussa P25 titania were characterized chemically and physically, revealing that the sample consists of nanoparticles, but has become crowded. Tests Samples (TS) were manufactured with added titania and the NO x tests at 28, 60 and 120 days of age of TSs, showing that it was 3% capable of degrading 100% of the NO x gas flow. Proved that conditions like relative humidity, flow and radiation intensity are relevant when it comes to efficiency in photocatalysis, altering the efficiency by varying these conditions. The photocatalysis with titania in cement matrix was efficient in NO x degradation, presenting itself as a promising technique to control environmental pollution

  8. The effect of CTAB on synthesis in butanol of samaria and gadolinia doped ceria - nickel oxide ceramics

    International Nuclear Information System (INIS)

    Arakaki, A.R.; Cunha, S.M.; Yoshito, W.K.; Ussui, V.; Lazar, D.R.R.

    2011-01-01

    In this work it was synthesized doped ceria and Samaria gadolinia - nickel oxide ceramics, mainly applied as anodes Fuel Cells Solid Oxide. Powders of composition Ce 0,8 (SmGd) 0,2 O 1,9 /NiO and mass ratio of 40: 60% were initially synthesized by hydroxides coprecipitation and then treated solvo thermically in butanol. Cerium samarium, gadolinium and nickel chlorides and CTAB with molar ratio metal / CTAB ranging from 1 to 3, were used as raw materials Powders were treated in butanol at 150 deg C for 16h. The powders were analyzed by X-ray diffraction, scanning electron microscopy, specific surface area for adsorption of nitrogen and particle size distribution by laser beam scattering. The ceramics were analyzed by scanning electron microscopy and density measurements by immersion technique in water. The results showed that the powders had the characteristic crystalline structures of ceria and nickel hydroxide, and high specific surface area (80 m 2 / g). The characterizations of ceramics demonstrated high chemical homogeneity and porosity values of 30%. (author)

  9. Microstructure characteristic of ceramic coatings fabricated on magnesium alloys by micro-arc oxidation in alkaline silicate solutions

    Energy Technology Data Exchange (ETDEWEB)

    Guo, H.F. [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China)]. E-mail: Guohf@hit.edu.cn; An, M.Z. [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China)]. E-mail: mzan@hit.edu.cn; Huo, H.B. [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Xu, S. [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Wu, L.J. [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China)

    2006-09-15

    Micro-arc oxidation (MAO) of AZ31B magnesium alloys was studied in alkaline silicate solutions at constant applied current densities. The microstructure, phase composition and elemental distribution of ceramic coatings were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy-dispersive spectroscopy (EDX). There are two inflections in the voltage-time response, three regions were identifiable and each of the regions was almost linear. The pores with different shapes distributed all over the coating surface, the number of the pores was decreasing, while the diameter was apparently increasing with prolonged MAO treatment time. There were also cracks on the coating surface, resulting from the rapid solidification of the molten oxide. The ceramic coating was comprised of two layers, an outer loose layer and an inner dense layer. The ceramic coating was mainly composed of forsterite phase Mg{sub 2}SiO{sub 4} and MgO; the formation of MgO was similar to conversional anodizing technology, while formation of Mg{sub 2}SiO{sub 4} was attributed to a high temperature phase transformation reaction. Presence of Si and O indicated that the electrolyte components had intensively incorporated into coatings.

  10. Removal of Congo Red by magnetic mesoporous titanium dioxide-graphene oxide core-shell microspheres for water purification.

    Science.gov (United States)

    Li, Leilei; Li, Xiangjun; Duan, Huimin; Wang, Xiaojiao; Luo, Chuannan

    2014-06-14

    Magnetic mesoporous titanium dioxide-graphene oxide (Fe3O4@mTiO2@GO) with a large surface area and a good magnetic responsiveness was synthesized by immobilizing a mesoporous titanium dioxide (mTiO2) shell on the surface of magnetic Fe3O4 nanoparticles prior to binding with graphene oxide (GO). It showed a tunable pore structure and surface properties, and was mechanically strong. The characteristic results of a Fourier transform infrared spectrometer (FTIR), a scanning electron microscope (SEM), a vibrating sample magnetometer (VSM) and X-ray diffraction (XRD) indicated that Fe3O4@mTiO2@GO has been prepared. Fe3O4@mTiO2@GO was used as an adsorbent for the removal of Congo Red (CR) from simulated wastewater with a fast solid-liquid separation in the presence of an external magnetic field. Batch adsorption experiments were performed to evaluate the adsorption conditions and reusability. The results showed that the maximum adsorption capacity was 89.95 mg g(-1), which is much higher than the previously reported values of other absorbent materials. Moreover, the Fe3O4@mTiO2@GO could be repeatedly used via simple treatment without any obvious structure and performance degradation. The adsorption kinetic data were best described by a pseudo-second-order model and the equilibrium adsorptions were well-described by the Freundlich isotherm model. The Fe3O4@mTiO2@GO may be suitable materials for use in CR pollution cleanup if synthesized on a large scale and at a low price in the near future.

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

    Directory of Open Access Journals (Sweden)

    Krzysztof Rokosz

    2018-02-01

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

  12. Role of surfactant-mediated electrodeposited titanium oxide substrate in improving electrocatalytic features of supported platinum particles

    Energy Technology Data Exchange (ETDEWEB)

    Spătaru, Tanţa; Preda, Loredana; Osiceanu, Petre; Munteanu, Cornel; Anastasescu, Mihai; Marcu, Maria; Spătaru, Nicolae, E-mail: nspataru@icf.ro

    2014-01-01

    A new hybrid system with improved photocatalytic and electrocatalytic performances was obtained by two-step potentiostatic deposition on highly boron-doped diamond (BDD) substrate. First, hydrated TiO{sub 2} was anodically deposited from a TiCl{sub 3} aqueous solution, both in the presence and in the absence of sodium dodecyl sulfate (SDS). The study of the UV irradiation effect evidenced that titanium oxide coatings obtained by surfactant-assisted electrodeposition (TiO{sub 2}:SDS) exhibit enhanced photocurrent, due to its very rough texonsture and presumably to better efficiency of charge carrier separation. Electrochemical deposition of platinum on the oxide-coated BDD was carried out in a second step and AFM, SEM and XPS measurements have shown that, on the TiO{sub 2}:SDS substrate, Pt particles are smaller, more uniformly distributed, and tend to form clusters, leading to a specific surface area of the electrocatalyst of ca. 6.55 m{sup 2} g{sup −1}. Carbon monoxide stripping experiments demonstrated that, when deposited on TiO{sub 2}:SDS, Pt particles are also less sensitive to CO-poisoning during methanol anodic oxidation.

  13. Effects of UV Aging on the Cracking of Titanium Oxide Layer on Poly(ethylene terephthalate) Substrate: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chao; Gray, Matthew H.; Tirawat, Robert; Larsen, Ross E.; Chen, Fangliang

    2016-04-18

    Thin oxide and metal films deposited on polymer substrates is an emerging technology for advanced reflectors for concentrated solar power applications, due to their unique combination of light weight, flexibility and inexpensive manufacture. Thus far, there is little knowledge on the mechanical integrity or structural persistence of such multi-layer thin film systems under long-term environmental aging. In this paper, the cracking of a brittle titanium dioxide layer deposited onto elasto-plastic poly(ethylene terephthalate) (PET) substrate is studied through a combination of experiment and modeling. In-situ fragmentation tests have been conducted to monitor the onset and evolution of cracks both on pristine and on samples aged with ultraviolet (UV) light. An analytical model is presented to simulate the cracking behavior and to predict the effects of UV aging. Based on preliminary experimental observation, the effect of aging is divided into three aspects and analyzed independently: mechanical property degradation of the polymer substrate; degradation of the interlayer between substrate and oxide coating; and internal stress-induced cracks on the oxide coating.

  14. Electrical instability of InGaZnO thin-film transistors with and without titanium sub-oxide layer under light illumination

    Science.gov (United States)

    Chiu, Y. C.; Zheng, Z. W.; Cheng, C. H.; Chen, P. C.; Yen, S. S.; Fan, C. C.; Hsu, H. H.; Kao, H. L.; Chang, C. Y.

    2017-03-01

    The electrical instability behaviors of amorphous indium-gallium-zinc oxide thin-film transistors with and without titanium sub-oxide passivation layer were investigated under light illumination in this study. For the unpassivated IGZO TFT device, in contrast with the dark case, a noticeable increase of the sub-threshold swing was observed when under the illumination environment, which can be attributed to the generation of ionized oxygen vacancies within the α-IGZO active layer by high energy photons. For the passivated TFT device, the much smaller SS of 70 mV/dec and high device mobility of >100 cm2/Vs at a drive voltage of 3 V with negligible degradation under light illumination are achieved due to the passivation effect of n-type titanium sub-oxide semiconductor, which may create potential application for high-performance display.

  15. Titanium modified with layer-by-layer sol-gel tantalum oxide and an organodiphosphonic acid: a coating for hydroxyapatite growth.

    Science.gov (United States)

    Arnould, C; Volcke, C; Lamarque, C; Thiry, P A; Delhalle, J; Mekhalif, Z

    2009-08-15

    Titanium and its alloys are widely used in surgical implants due to their appropriate properties like corrosion resistance, biocompatibility, and load bearing. Unfortunately when metals are used for orthopedic and dental implants there is the possibility of loosening over a long period of time. Surface modification is a good way to counter this problem. A thin tantalum oxide layer obtained by layer-by-layer (LBL) sol-gel deposition on top of a titanium surface is expected to improve biocorrosion resistance in the body fluid, biocompatibility, and radio-opacity. This elaboration step is followed by a modification of the tantalum oxide surface with an organodiphosphonic acid self-assembled monolayer, capable of chemically binding to the oxide surface, and also improving hydroxyapatite growth. The different steps of this proposed process are characterized by surfaces techniques like contact angle, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM).

  16. Phenol Photocatalytic Degradation by Advanced Oxidation Process under Ultraviolet Radiation Using Titanium Dioxide

    Directory of Open Access Journals (Sweden)

    Ali Nickheslat

    2013-01-01

    Full Text Available Background. The main objective of this study was to examine the photocatalytic degradation of phenol from laboratory samples and petrochemical industries wastewater under UV radiation by using nanoparticles of titanium dioxide coated on the inner and outer quartz glass tubes. Method. The first stage of this study was conducted to stabilize the titanium dioxide nanoparticles in anatase crystal phase, using dip-coating sol-gel method on the inner and outer surfaces of quartz glass tubes. The effect of important parameters including initial phenol concentration, TiO2 catalyst dose, duration of UV radiation, pH of solution, and contact time was investigated. Results. In the dip-coat lining stage, the produced nanoparticles with anatase crystalline structure have the average particle size of 30 nm and are uniformly distributed over the tube surface. The removal efficiency of phenol was increased with the descending of the solution pH and initial phenol concentration and rising of the contact time. Conclusion. Results showed that the light easily passes through four layers of coating (about 105 nm. The highest removal efficiency of phenol with photocatalytic UV/TiO2 process was 50% at initial phenol concentration of 30 mg/L, solution pH of 3, and 300 min contact time. The comparison of synthetic solution and petrochemical wastewater showed that at same conditions the phenol removal efficiency was equal.

  17. Titanium Brazing for Structures and Survivability

    National Research Council Canada - National Science Library

    Doherty, Kevin J; Tice, Jason R; Szewczyk, Steven T; Glide, Gary A

    2007-01-01

    .... While welding is the typical joining method for titanium, vacuum brazing is an option in areas that are difficult to access for welding as well as areas near other nonmetallic materials, such as ceramics...

  18. Fracture mechanical investigations about crack resistance behaviour in non-transforming ceramics in particular aluminum oxide

    International Nuclear Information System (INIS)

    Baer, K.K.O.; Kleist, G.; Nickel, H.

    1991-03-01

    The aim of this work is the clearification of R-curve behaviour of non-transforming ceramics, in particular aluminum oxide exhibiting incrystalline fracture. Investigations of crack growth in controlled bending experiments were performed using 3-Pt- and 4-Pt-bending samples of differing sizes under inert conditions. The fracture experiments were realized using several loading techniques, for example constant and varying displacement rates, load rupture (P = 0) and relaxation tests (v = 0). In addition unloading and reloading experiments were performed to investigate hysteresis curves and residual displacements in accordance with R-curve behaviour. During the crack-growth experiments, the crack extension was measured in situ using a high resolution immersion microscope. With this technique, the fracture processes near the crack tip (crack activity zone) was observed as well. The crack resistance as a function of crack extension (R-curve) was determined using differing calculation methods. All of the methods used resulted in approximately identical R-curves, within the statistical error band. The crack resistance at initiation R 0 was 20 N/m. The crack resistance increased during approximately 3 mm of growth to a maximum of 90 N/m. A decrease in the crack resistance was determined for large a/W (crack length normalized with sample height) values, independant of the calculation methods. The R-curve behaviour was interpreted as due to a functional resistance behind the observed crack tip, which arises from a volume dilatation in the crack activity zone while the crack proceeds. (orig.) [de

  19. Structural characterization of clays commercially used in red ceramics

    International Nuclear Information System (INIS)

    Brito, E.M.; Moura, J.K.L.; Souza, R.B.; Brandim, A.S.

    2014-01-01

    The use of clays hills being an alternative to clay floodplain, due to environmental protection laws. The research project aims at the morphological and chemical characterization of hills clays used industrially for the production of ceramic tiles and blocks. Therefore, two types of methods were known commercially in the region of Teresina-PI through diffraction of X-rays (X-DR), scanning electron microscopy (SEM) and energy dispersive spectrometry X-ray (EDS). It can be observed that the samples have a high percentage of quartz, hematite still having in its constitution aluminum oxide, zirconium oxide and titanium oxide. The results show that the clays are clays and montmorillonites may be used for the production of ceramic tiles and blocks, but as the proportion of using the same will be focusing the next job. (author)

  20. Flash sintering of ceramic materials

    Science.gov (United States)

    Dancer, C. E. J.

    2016-10-01

    During flash sintering, ceramic materials can sinter to high density in a matter of seconds while subjected to electric field and elevated temperature. This process, which occurs at lower furnace temperatures and in shorter times than both conventional ceramic sintering and field-assisted methods such as spark plasma sintering, has the potential to radically reduce the power consumption required for the densification of ceramic materials. This paper reviews the experimental work on flash sintering methods carried out to date, and compares the properties of the materials obtained to those produced by conventional sintering. The flash sintering process is described for oxides of zirconium, yttrium, aluminium, tin, zinc, and titanium; silicon and boron carbide, zirconium diboride, materials for solid oxide fuel applications, ferroelectric materials, and composite materials. While experimental observations have been made on a wide range of materials, understanding of the underlying mechanisms responsible for the onset and latter stages of flash sintering is still elusive. Elements of the proposed theories to explain the observed behaviour include extensive Joule heating throughout the material causing thermal runaway, arrested by the current limitation in the power supply, and the formation of defect avalanches which rapidly and dramatically increase the sample conductivity. Undoubtedly, the flash sintering process is affected by the electric field strength, furnace temperature and current density limit, but also by microstructural features such as the presence of second phase particles or dopants and the particle size in the starting material. While further experimental work and modelling is still required to attain a full understanding capable of predicting the success of the flash sintering process in different materials, the technique non-etheless holds great potential for exceptional control of the ceramic sintering process.

  1. Chemical changes of titanium and titanium dioxide under electron bombardment

    Directory of Open Access Journals (Sweden)

    Romins Brasca

    2007-09-01

    Full Text Available The electron induced effect on the first stages of the titanium (Ti0 oxidation and titanium dioxide (Ti4+ chemical reduction processes has been studied by means of Auger electron spectroscopy. Using factor analysis we found that both processes are characterized by the appearance of an intermediate Ti oxidation state, Ti2O3 (Ti3+.

  2. Synthesis and analysis of Mo-Si-B based coatings for high temperature oxidation protection of ceramic materials

    Science.gov (United States)

    Ritt, Patrick J.

    The use of Ni-based superalloys in turbine engines has all but been exhausted, with operating temperatures nearing the melting point of these materials. The use of ceramics in turbine engines, particularly ceramic matrix composites such as SiC/C and SiC/SiC, is of interest due to their low density and attractive mechanical properties at elevated temperatures. The same materials are also in consideration for leading edges on hypersonic vehicles. However, SiC-based composites degrade in high temperature environments with low partial pressures of oxygen due to active oxidation, as well as high temperature environments containing water or sand. The need for a protective external coating for SiC-based composites in service is obvious. To date, no coating investigated for SiC/C or SiC/SiC has been proven to be resistant to oxidation and corrosion at intermediate and high temperatures, as well as in environments deficient in oxygen. The Mo-Si-B coating shows great promise in this area, having been proven resistant to attack from oxidation at extreme temperatures, from water vapor and from calcia-magnesia-aluminosilicate (CMAS). The adaptation of the Mo-Si-B coating for ceramic materials is presented in detail here. Evaluation of the coating under a range of oxidation conditions as well as simulated re-entry conditions confirms the efficacy of the Mo-Si-B based coating as protection from catastrophic failure. The key to the oxidation and corrosion resistance is a robust external aluminoborosilica glass layer that forms and flows quickly to cover the substrate, even under the extreme simulated re-entry conditions. Suppression of active oxidation of SiC, which may occur during atmospheric re-entry and hypersonic flight trajectories, has also been examined. In order to adapt the Mo-Si-B based coating to low partial pressures of oxygen and elevated temperatures, controlled amounts of Al were added to the Mo-Si-B based coating. The resulting coating decreased the inward

  3. Improved optical response and photocatalysis for N-doped titanium oxide (TiO2) films prepared by oxidation of TiN

    International Nuclear Information System (INIS)

    Wan, L.; Li, J.F.; Feng, J.Y.; Sun, W.; Mao, Z.Q.

    2007-01-01

    In order to improve the photocatalytic activity, N-doped titanium oxide (TiO 2 ) films were obtained by thermal oxidation of TiN films, which were prepared on Ti substrates by ion beam assisted deposition (IBAD). The dominating rutile TiO 2 phase was found in films after thermal oxidation. According to the results of X-ray photoelectron spectroscopy (XPS), the residual N atoms occupied O-atom sites in TiO 2 lattice to form Ti-O-N bonds. UV-vis spectra revealed the N-doped TiO 2 film had a red shift of absorption edge. The maximum red shift was assigned to the sample annealed at 750 deg. C, with an onset wavelength at 600 nm. The onset wavelength corresponded to the photon energy of 2.05 eV, which was nearly 1.0 eV below the band gap of pure rutile TiO 2 . The effect of nitrogen was responsible for the enhancement of photoactivity of N-doped TiO 2 films in the range of visible light

  4. Flexible Lithium-Ion Fiber Battery by the Regular Stacking of Two-Dimensional Titanium Oxide Nanosheets Hybridized with Reduced Graphene Oxide.

    Science.gov (United States)

    Hoshide, Tatsumasa; Zheng, Yuanchuan; Hou, Junyu; Wang, Zhiqiang; Li, Qingwen; Zhao, Zhigang; Ma, Renzhi; Sasaki, Takayoshi; Geng, Fengxia

    2017-06-14

    Increasing interest has recently been devoted to developing small, rapid, and portable electronic devices; thus, it is becoming critically important to provide matching light and flexible energy-storage systems to power them. To this end, compared with the inevitable drawbacks of being bulky, heavy, and rigid for traditional planar sandwiched structures, linear fiber-shaped lithium-ion batteries (LIB) have become increasingly important owing to their combined superiorities of miniaturization, adaptability, and weavability, the progress of which being heavily dependent on the development of new fiber-shaped electrodes. Here, we report a novel fiber battery electrode based on the most widely used LIB material, titanium oxide, which is processed into two-dimensional nanosheets and assembled into a macroscopic fiber by a scalable wet-spinning process. The titania sheets are regularly stacked and conformally hybridized in situ with reduced graphene oxide (rGO), thereby serving as efficient current collectors, which endows the novel fiber electrode with excellent integrated mechanical properties combined with superior battery performances in terms of linear densities, rate capabilities, and cyclic behaviors. The present study clearly demonstrates a new material-design paradigm toward novel fiber electrodes by assembling metal oxide nanosheets into an ordered macroscopic structure, which would represent the most-promising solution to advanced flexible energy-storage systems.

  5. Optical properties of titanium di-oxide thin films prepared by dip coating method

    Science.gov (United States)

    Biswas, Sayari; Rahman, Kazi Hasibur; Kar, Asit Kumar

    2018-05-01

    Titanium dioxide (TiO2) thin films were prepared by sol-gel dip coating method on ITO coated glass substrate. The sol was synthesized by hydrothermal method at 90°C. The sol was then used to make TiO2 films by dip coating. After dip coating the rest of the sol was dried at 100°C to make TiO2 powder. Thin films were made by varying the number of dipping cycles and were annealed at 500°C. XRD study was carried out for powder samples that confirms the formation of anatase phase. Transmission spectra of thin films show sharp rise in the violet-ultraviolet transition region and a maximum transmittance of ˜60%. Band gap of the prepared films varies from 3.15 eV to 3.22 eV.

  6. Alumina and Hafnia ALD Layers for a Niobium-Doped Titanium Oxide Photoanode

    Directory of Open Access Journals (Sweden)

    Naji Al Dahoudi

    2012-01-01

    Full Text Available Niobium-doped titanium dioxide (TiO2 nanoparticles were used as a photoanode in dye-sensitized solar cells (DSCs. They showed a high photocurrent density due to their higher conductivity; however, a low open-circuit voltage was exhibited due to the back-reaction of photogenerated electrons. Atomic layer deposition is a useful technique to form a conformal ultrathin layer of Al2O3 and HfO, which act as an energy barrier to suppress the back electrons from reaching the redox medium. This resulted in an increase of the open-circuit voltage and therefore led to higher performance. HfO showed an improvement of the light-to-current conversion efficiency by 74%, higher than the 21% enhancement obtained by utilizing Al2O3 layers.

  7. An Overview: Recent Development of Titanium Oxide Nanotubes as Photocatalyst for Dye Degradation

    Directory of Open Access Journals (Sweden)

    Chin Wei Lai

    2014-01-01

    Full Text Available Today, organic dyes are one of the largest groups of pollutants release into environment especially from textile industry. It is highly toxic and hazardous to the living organism; thus, the removal of these dyes prior to discharge into the environment is essential. Varieties of techniques have been employed to degrade organic dyes and heterogeneous photocatalysis involving titanium dioxide (TiO2 appears to be the most promising technology. In recent years, TiO2 nanotubes have attracted much attention due to their high surface area and extraordinary characteristics. This paper presents a critical review of recent achievements in the modification of TiO2 nanotubes for dye degradation. The photocatalytic activity on dye degradation can be further enhanced by doping with cationic or anionic dopant.

  8. Layered titanium disilicide stabilized by oxide coating for highly reversible lithium insertion and extraction.

    Science.gov (United States)

    Zhou, Sa; Simpson, Zachary I; Yang, Xiaogang; Wang, Dunwei

    2012-09-25

    The discovery of new materials has played an important role in battery technology development. Among the newly discovered materials, those with layered structures are often of particular interest because many have been found to permit highly repeatable ionic insertion and extraction. Examples include graphite and LiCoO(2) as anode and cathode materials, respectively. Here we report C49 titanium disilicide (TiSi(2)) as a new layered anode material, within which lithium ions can react with the Si-only layers. This result is enabled by the strategy of coating a thin (lithium-ion storage capacity of TiSi(2) is a result of its layered structure is expected to have major fundamental and practical implications.

  9. No evidence of the genotoxic potential of gold, silver, zinc oxide and titanium dioxide nanoparticles in the SOS chromotest.

    Science.gov (United States)

    Nam, Sun-Hwa; Kim, Shin Woong; An, Youn-Joo

    2013-10-01

    Gold nanoparticles (Au NPs), silver nanoparticles (Ag NPs), zinc oxide nanoparticles (ZnO NPs) and titanium dioxide nanoparticles (TiO2 NPs) are widely used in cosmetic products such as preservatives, colorants and sunscreens. This study investigated the genotoxicity of Au NPs, Ag NPs, ZnO NPs and TiO2 NPs using the SOS chromotest with Escherichia coli PQ37. The maximum exposure concentrations for each nanoparticle were 3.23 mg l(-1) for Au NPs, 32.3 mg l(-1) for Ag NPs and 100 mg l(-1) for ZnO NPs and TiO2 NPs. Additionally, in order to compare the genotoxicity of nanoparticles and corresponding dissolved ions, the ions were assessed in the same way as nanoparticles. The genotoxicity of the titanium ion was not assessed because of the extremely low solubility of TiO2 NPs. Au NPs, Ag NPs, ZnO NPs, TiO2 NPs and ions of Au, Ag and Zn, in a range of tested concentrations, exerted no effects in the SOS chromotest, evidenced by maximum IF (IFmax) values of below 1.5 for all chemicals. Owing to the results, nanosized Au NPs, Ag NPs, ZnO NPs, TiO2 NPs and ions of Au, Ag and Zn are classified as non-genotoxic on the basis of the SOS chromotest used in this study. To the best of our knowledge, this is the first study to evaluate the genotoxicity of Au NPs, Ag NPs, ZnO NPs and TiO2 NPs using the SOS chromotest. Copyright © 2012 John Wiley & Sons, Ltd.

  10. Synthesis and characterization of titanium and yttrium precursors with unsaturated ligands: application to the doping of low-density micro-molecular materials oxides

    International Nuclear Information System (INIS)

    Gamet-Cauro, L.-C.

    2001-01-01

    The laser-matter interaction experiments for high-power pulsed lasers require doped micro-targets. The ablator is a Low-Density Microcellular Material,foam namely a styrene-divinylbenzene copolymer obtained by a HIPE process (High Internal Polymerisation Emulsion). The spectroscopic tracers selected for doping are titanium, yttrium and aluminium as oxides. For obtaining these hybrid organic-inorganic materials, precursors with polymerizable ligands were introduced during the emulsification step since the unsaturation of the ligands could participate in the copolymerization reaction. We report here in the synthesis and characterization of titanium and yttrium precursors with polymerizable ligands. The structures of [Ti(O i Pr) 3 (AMP)] 2 (HAMP allyl-methylphenol), [Ti(OEt) 3 (AAA)] 2 (HAAA allylacetoacetate), Y 8 O 2 (OH) 4 (OEt) 6 (AAA) 10 were established by X-ray diffraction. Ti 4 O 3 (OR) 8 (AAA) 2 (R Et, i Pr).[TiO(O i Pr)(oleate)] m , Y 4 (OH) 2 (AAA) 5 , Y 4 O(O i Pr) 5 (AAA) 5 , Y 4 (OH) 4 Cl 5 (AAA) 3 (THF) 3 have been prepared as well and characterized by FT-IR, 1 HNMR and elemental analysis. Micro-hydrolysis reactions of titanium derivatives were investigated. The rates of polymerisation and copolymerization with styrene were evaluated for the titanium precursors with polymerizable ligands. The parameters of the HIPE process were adapted to the fabrication of doped foams, only the dopant and initiator change. We discuss incorporation mechanisms of titanium oxide and yttrium oxo-hydroxides: precursor-surfactant interaction, copolymerization of precursors with unsaturated ligands and physical or chemical retention. The foams have been characterized by scanning electron microscopy (morphology), elemental analysis and fluorescence X cartography (amount, distribution of metal oxide), adsorption isotherms (BET, texture), compression tests (mechanical strength). Due to this systematic study, a good control of doping has become possible and allowed us to develop

  11. Photocatalytic oxidation of acetaminophen using carbon self-doped titanium dioxide

    Directory of Open Access Journals (Sweden)

    Mark Daniel G. de Luna

    2016-07-01

    Full Text Available A new carbon self-doped (C-doped TiO2 photocatalyst was synthesized by sol–gel method, in which titanium butoxide was utilized because of its dual functions as a titanium precursor and a carbon source. The effects of calcination temperature from 200 to 600 °C on the photocatalytic activity towards acetaminophen (ACT, which was used as a model persistent organic pollutant under visible light were examined. The effects of temperature on the structure and physicochemical properties of the C-doped TiO2 were also investigated by X-ray diffraction, BET measurement, X-ray photoelectron spectroscopy, and scanning electron microscopy. The specific surface area of the as-doped TiO2 declined as the crystal size increased with increasing calcination temperature. Only amorphous TiO2 was present at 200 °C, while an anatase phase was observed between 300 and 500 °C. Both anatase and rutile phases were observed at 600 °C. Photocatalytic activity increased as the calcination temperature initially increased from 200 to 300 °C but it decreased as the calcination temperature further increased from 400 to 600 °C. The highest ACT removal of 94% with an apparent rate constant of 5.0 × 10−3 min−1 was achieved using the new doped TiO2 calcined at 300 °C, which had an atomic composition of 31.6% Ti2p3, 50.3% O1s and 18.2% C1s.

  12. Oxygen-implanted induced formation of oxide layer enhances blood compatibility on titanium for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Hung, Wei-Chiang [School of Oral Hygiene, Taipei Medical University, Taipei 110, Taiwan (China); Department of Dentistry, Taipei Medical University Hospital, Taipei 110, Taiwan (China); Chang, Fang-Mo [School of Dentistry, Taipei Medical University, Taipei 110, Taiwan (China); Yang, Tzu-Sen [Master Program in Graduate Institute of Nanomedicine and Medical Engineering, Taipei Medical University, Taipei 110, Taiwan (China); Ou, Keng-Liang [School of Dentistry, Taipei Medical University, Taipei 110, Taiwan (China); Research Center for Biomedical Implants and Microsurgery Devices, Taipei Medical University, Taipei 110, Taiwan (China); Department of Dentistry, Taipei Medical University-Shuang-Ho Hospital, Taipei 235, Taiwan (China); Lin, Che-Tong [School of Dentistry, Taipei Medical University, Taipei 110, Taiwan (China); Peng, Pei-Wen, E-mail: apon@tmu.edu.tw [School of Dental Technology, Taipei Medical University, Taipei 110, Taiwan (China)

    2016-11-01

    Titanium dioxide (TiO{sub 2}) layers were prepared on a Ti substrate by using oxygen plasma immersion ion implantation (oxygen PIII). The surface chemical states, structure, and morphology of the layers were studied using X-ray photoelectron spectroscopy, X-ray diffraction, Raman microscopy, atomic force microscopy and scanning electron microscope. The mechanical properties, such as the Young's modulus and hardness, of the layers were investigated using nanoindentation testing. The Ti{sup 4+} chemical state was determined to be present on oxygen-PIII-treated surfaces, which consisted of nanocrystalline TiO{sub 2} with a rutile structure. Compared with Ti substrates, the oxygen-PIII-treated surfaces exhibited decreased Young's moduli and hardness. Parameters indicating the blood compatibility of the oxygen-PIII-treated surfaces, including the clotting time and platelet adhesion and activation, were studied in vitro. Clotting time assays indicated that the clotting time of oxygen-PIII-treated surfaces was longer than that of the Ti substrate, which was associated with decreased fibrinogen adsorption. In conclusion, the surface characteristics and the blood compatibility of Ti implants can be modified and improved using oxygen P