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Sample records for preparing aluminum surfaces

  1. The Role of Surface Preparation Parameters on Cold Roll Bonding of Aluminum Strips

    Science.gov (United States)

    Jamaati, Roohollah; Toroghinejad, Mohammad Reza

    2011-03-01

    It is the objective of this article to investigate the influence of surface preparation on the cold roll bonding (CRB) process. In this context, the effects of surface preparation parameters consisting of surface preparation method, surface roughness, scratch-brushing parameters, and the delay time between surface preparation and rolling are investigated on the bond strength of aluminum strips. The bond strength of two adjacent aluminum strips produced by the CRB process is evaluated by the peeling test. Furthermore, the interface region is investigated by metallographic observations. Our findings indicate that higher surface roughness values and shorter delay times improve the bond strength. It is also found that degreasing followed by scratch-brushing yield the best bonding properties.

  2. Study of Influencing Factors and the Mechanism of Preparing Triazinedithiol Polymeric Nanofilms on Aluminum Surfaces

    Directory of Open Access Journals (Sweden)

    Yanni Li

    2010-11-01

    Full Text Available Triazinedithiol polymeric nanofilm was prepared on a pure aluminum surface by electrochemical polymerization of AF17N. The mechanism of the process was proposed and electrochemical polymerization parameters were investigated. The triazinedithiol polymeric nanofilm had notable lubricity, high dielectric property and superhydrophobic property due to the allyl and fluoro alkyl groups in the AF17N monomer. The chemical structure of poly (6-(N-allyl-1,1,2,2-tetrahydroperfluorodecylamino-1,3,5-triazine-2,4-dithiol monosodium nanofilm (PAF17 was investigated by analysis of FT-IR spectra and X-ray photoelectron spectroscopy (XPS. The optimal conditions for the preparation process were based on the data of film weight and thickness. The optimal parameters of monomer concentration, electropolymerization time and temperature were 5 mM, 6 min and 15 °C, respectively. The electropolymerization mechanism was a radical polymerization reaction. It is expected that this technique will be applied in industrial fields for aluminum and aluminum alloy to achieve functional surfaces.

  3. A novel simple approach to preparation of superhydrophobic surfaces of aluminum alloys

    Science.gov (United States)

    Xie, Degang; Li, Wen

    2011-11-01

    A novel two-step methodology is successfully developed to fabricate superhydrophobic surfaces of aluminum alloys. The essential procedure is that samples are first immersed and etched in a boiling aqueous solution of NaOH for 5 min without preprocessing, and then they are modified for 30 min in an ethanol solution of lauric acid, cheaper and more efficient than the fluorinated silane frequently adopted by other researchers. If the concentration of NaOH solution is larger than 5 g/L, the contact angle of the prepared surfaces will be larger than 150° with a negligible hysteresis. Such a fast, low-cost, and reliable method for superhydrophobic surfaces implies significant promising industrial applications.

  4. Standard Methods of Analysis of Sulfochromate Etch Solution Used in Surface Preparation of Aluminum

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2012-01-01

    1.1 These methods offer a means for controlling the effectiveness of the etchant which is normally used for preparing the surface of aluminum alloys for subsequent adhesive bonding. As the etchant reacts with the aluminum, hexavalent chromium is converted to trivalent chromium; a measure of the two and the difference can be used to determine the amount of dichromate used. 1.2 The sulfochromate solution can be replenished by restoring the sodium dichromate and the sulfuric acid to the original formulation levels. The lower limit of usefulness will vary depending upon solution storage, adhesives used, critical nature of bond capability, variety of metals processed, etc. and should be determined. Replenishment will be limited to the number of times the chemical ingredients can be restored and maintained to the required levels and should be determined by the user. Sludge collecting in the bottom of a tank should be minimized by periodic removal of sludge. For some applications, the hexavalent chromium should not ...

  5. The use of Erbium: Yttrium-aluminum-garnet laser in cavity preparation and surface treatment: 3-year follow-up.

    Science.gov (United States)

    Buyukhatipoglu, Isil; Secilmis, Asli

    2015-01-01

    From the currently available choices, esthetic restorative materials for posterior teeth are limited to composite and ceramic restoration. Ceramic inlays/onlays are reliable solutions for both of these treatments. For successful treatment planning, usable ceramic and adhesive systems should be chosen by the dentist. Since the Federal Drug Administration approval of the erbium: Yttrium-aluminum-garnet (Er:YAG) laser-for caries removal, cavity preparation and the conditioning of tooth substance-in 1997, there have been many reports on the use of this technique in combination with composite resins. In addition, cavity pretreatment with the Er:YAG laser (laser etching) has been proposed as an alternative to acid etching of enamel and dentin. This case report presents the use of the Er:YAG in cavity preparation for composite resin restoration and surface treatment for ceramic onlay restoration of adjacent permanent molars.

  6. The use of Erbium: Yttrium-aluminum-garnet laser in cavity preparation and surface treatment: 3-year follow-up

    Science.gov (United States)

    Buyukhatipoglu, Isil; Secilmis, Asli

    2015-01-01

    From the currently available choices, esthetic restorative materials for posterior teeth are limited to composite and ceramic restoration. Ceramic inlays/onlays are reliable solutions for both of these treatments. For successful treatment planning, usable ceramic and adhesive systems should be chosen by the dentist. Since the Federal Drug Administration approval of the erbium: Yttrium-aluminum-garnet (Er:YAG) laser-for caries removal, cavity preparation and the conditioning of tooth substance-in 1997, there have been many reports on the use of this technique in combination with composite resins. In addition, cavity pretreatment with the Er:YAG laser (laser etching) has been proposed as an alternative to acid etching of enamel and dentin. This case report presents the use of the Er:YAG in cavity preparation for composite resin restoration and surface treatment for ceramic onlay restoration of adjacent permanent molars. PMID:26038665

  7. Preparation and Surface Analysis of PPY/SDBS Films on Aluminum Substrates

    Directory of Open Access Journals (Sweden)

    Lisete C. Scienza

    2001-09-01

    Full Text Available Polypyrrole films were generated on high purity aluminum substrates under anodic polarization from aqueous electrolytes comprised of pyrrole and sodium dodecylbenzene sulfonate. The methods employed to characterize the polymer films included scanning electron microscopy, Fourier-transform infrared and X-photoelectron spectroscopy and X-ray diffraction. PPY/SDBS films revealed nodular morphology with occasional appearing of "dendrites", high level of protonation, excess of counter-anions ([S]/[N] > [N+]/[N] and high degrees of disorder.

  8. Preparation of gallium nitride surfaces for atomic layer deposition of aluminum oxide.

    Science.gov (United States)

    Kerr, A J; Chagarov, E; Gu, S; Kaufman-Osborn, T; Madisetti, S; Wu, J; Asbeck, P M; Oktyabrsky, S; Kummel, A C

    2014-09-14

    A combined wet and dry cleaning process for GaN(0001) has been investigated with XPS and DFT-MD modeling to determine the molecular-level mechanisms for cleaning and the subsequent nucleation of gate oxide atomic layer deposition (ALD). In situ XPS studies show that for the wet sulfur treatment on GaN(0001), sulfur desorbs at room temperature in vacuum prior to gate oxide deposition. Angle resolved depth profiling XPS post-ALD deposition shows that the a-Al2O3 gate oxide bonds directly to the GaN substrate leaving both the gallium surface atoms and the oxide interfacial atoms with XPS chemical shifts consistent with bulk-like charge. These results are in agreement with DFT calculations that predict the oxide/GaN(0001) interface will have bulk-like charges and a low density of band gap states. This passivation is consistent with the oxide restoring the surface gallium atoms to tetrahedral bonding by eliminating the gallium empty dangling bonds on bulk terminated GaN(0001).

  9. Electrically Conductive Anodized Aluminum Surfaces

    Science.gov (United States)

    Nguyen, Trung Hung

    2006-01-01

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

  10. Formulation and method for preparing gels comprising hydrous aluminum oxide

    Science.gov (United States)

    Collins, Jack L.

    2014-06-17

    Formulations useful for preparing hydrous aluminum oxide gels contain a metal salt including aluminum, an organic base, and a complexing agent. Methods for preparing gels containing hydrous aluminum oxide include heating a formulation to a temperature sufficient to induce gel formation, where the formulation contains a metal salt including aluminum, an organic base, and a complexing agent.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-08-26

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

  12. Preparation of titanium/aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Jecker, G.

    1984-03-20

    Alloys comprising titanium and aluminum, or titanium, aluminum and at least one of the metals M, wherein M is vanadium, zirconium, chromium, niobium, tantalum and/or iron, are facilely prepared by reducing an alkali metal fluotitanate, or coreducing admixture of an alkali metal fluotitanate and at least one halide of a metal M, with aluminum, in the presence of an alkali metal oxide reactive flux, either Na/sub 2/O and/or K/sub 2/O; next solubilizing with water the fluorine compounds of reduction/coreduction which are in admixture of reduction/coreduction with dispersion of the aforesaid metals in metallic state; separating said dispersion of metals in metallic state from said admixture of reduction/coreduction; and then alloying by melting and cooling said separated dispersion of metals in metallic state.

  13. Preparation and characterization of aluminum stearate

    Directory of Open Access Journals (Sweden)

    Lončar Eva S.

    2003-01-01

    Full Text Available Preparation of aluminum stearate by the precipitation method was examined under various conditions of stearic acid saponification with sodium hydroxide. It was proved that the most favorable ratio of acid/alkali was 1:1.5 and that the obtained soap was very similar to the commercial product. Endothermic effects determined by differential scanning calorimetry and also the other parameters showed that the soaps consisted mono-, di-, tristearates and non-reacted substances, where distearate was the dominant form.

  14. Characterization of aluminum surfaces: Sorption and etching

    Science.gov (United States)

    Polkinghorne, Jeannette Clera

    Aluminum, due to its low density and low cost, is a key material for future lightweight applications. However, like other structural materials, aluminum is subject to various forms of corrosion damage that annually costs the United States approximately 5% of its GNP [1]. The main goal is to investigate the effects of various solution anions on aluminum surfaces, and specifically probe pit initiation and inhibition. Using surface analysis techniques including X-ray photoelectron spectroscopy, Auger electron spectroscopy, and scanning electron microscopy, results have been correlated with those obtained from electrochemical methods and a radiolabeling technique developed in the Wieckowski laboratory. Analysis of data has indicated that important variables include type of anion, solution pH, and applied electrode potential. While aggressive anions such as chloride are usually studied to elucidate corrosion processes to work ultimately toward inhibition, its corrosive properties can be successfully utilized in the drive for higher energy and smaller-scale storage devices. Fundamental information gained regarding anion interaction with the aluminum surface can be applied to tailor etch processes. Standard electrochemical techniques and SEM are respectively used to etch and analyze the aluminum substrate. Aluminum electrolytic capacitors are comprised of aluminum anode foil covered by an anodically grown aluminum oxide dielectric film, electrolytic paper impregnated with electrolyte, and aluminum cathode foil. Two main processes are involved in the fabrication of aluminum electrolytic capacitors, namely etching and anodic oxide formation. Etching of the anode foil results in a higher surface area (up to 20 times area enlargement compared to unetched foil) that translates into a higher capacitance gain, permitting more compact and lighter capacitor manufacture. Anodic oxide formation on the anode, creates the required dielectric to withstand high voltage operation. A

  15. Masking of aluminum surface against anodizing

    Science.gov (United States)

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

    1969-01-01

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

  16. Electrodeposition of aluminum on aluminum surface from molten salt

    Institute of Scientific and Technical Information of China (English)

    Wenmao HUANG; Xiangyu XIA; Bin LIU; Yu LIU; Haowei WANG; Naiheng MA

    2011-01-01

    The surface morphology,microstructure and composition of the aluminum coating of the electrodeposition plates in AlC13-NaC1-KC1 molten salt with a mass ratio of 8:1:1 were investigated by SEM and EDS.The binding force was measured by splat-cooling method and bending method.The results indicate that the coatings with average thicknesses of 12 and 9 μm for both plates treated by simple grinding and phosphating are compacted,continuous and well adhered respectively. Tetramethylammonium chloride (TMAC) can effectively prevent the growth of dendritic crystal,and the anode activation may improve the adhesion of the coating. Binding force analysis shows that both aluminum coatings are strongly adhered to the substrates.

  17. Porous Spherical Cellulose Composites Coated by Aluminum (Ⅲ) Oxide and Silicone: Preparation,Characterization and Adsorption Behavior

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Porous spherical cellulose composite (PSCA) coated by aluminum (Ⅲ) oxide was prepared andmodified by organosilicone. SEM images of the surface morphology of the bead cellulose shows that it hasspherical shape and abundant porous structure on its surface. The mapping images of aluminum and silicon ofthe composite (PSCAS) present aluminum( Ⅲ ) oxide and silicone are uniformly dispersed on the surface. Theadsorption behavior of PSCAS toward metal ions was determined.

  18. Experimental and Numerical Study of the Influence of Substrate Surface Preparation on Adhesion Mechanisms of Aluminum Cold Spray Coatings on 300M Steel Substrates

    Science.gov (United States)

    Nastic, A.; Vijay, M.; Tieu, A.; Rahmati, S.; Jodoin, B.

    2017-07-01

    The effect of substrate surface topography on the creation of metallurgical bonds and mechanical anchoring points has been studied for the cold spray deposition of pure aluminum on 300M steel substrate material. The coatings adhesion strength showed a significant decrease from 31.0 ± 5.7 MPa on polished substrates to 6.9 ± 2.0 MPa for substrates with roughness of 2.2 ± 0.5 μm. Strengths in the vicinity of 45 MPa were reached for coatings deposited onto forced pulsed waterjet treated surfaces with roughnesses larger than 33.8 μm. Finite element analysis has confirmed the sole presence of mechanical anchoring in coating adhesion strength for all surface treatment except polished surfaces. Grit embedment has been shown to be non-detrimental to coating adhesion for the current deposited material combination. The particle deformation process during impacts has been studied through finite element analysis using the Preston-Tonks-Wallace (PTW) constitutive model. The obtained equivalent plastic strain (PEEQ), temperature, contact pressure and velocity vector were correlated to the particle ability to form metallurgical bonds. Favorable conditions for metallurgical bonding were found to be highest for particles deposited on polished substrates, as confirmed by fracture surface analysis.

  19. Corrosion Resistance of Ni60 Coatings Prepared on Aluminum Bronze Surface by Flame Remelting%铝青铜表面粉末火焰喷涂Ni60合金涂层的耐蚀性研究

    Institute of Scientific and Technical Information of China (English)

    韩付会; 昌霞; 张小彬; 黄伟九

    2013-01-01

    Abstract:Ni60 coating was prepared on QAL9-4 aluminum bronze surface by using oxygen-acetylene flame spraying-remelting technology.The corrosion behavior of aluminum bronze matrix and Ni60 coating was studied in 3.5% NaCl solution by using static immersion test,electrochemical experiments,surface analysis technology etc.The results showed that the corrosion resistance of aluminum bronze matrix could be obviously improved after coated with Ni60 ; the corrosion mechanism of matrix was dealuminzation,and the corrosion process of coating was the preferential dissolution of Cr element.%采用氧-乙炔火焰喷涂-重熔技术在QAL9-4铝青铜表面制备Ni60合金涂层,通过静态浸泡试验、电化学实验及表面分析技术等方法对铝青铜基体和Ni60合金涂层在3.5%NaCl溶液中的腐蚀行为进行了研究.结果表明,Ni60合金涂层可以明显提高铝青铜基体的耐蚀性能;基体主要发生脱铝腐蚀,而涂层的腐蚀过程则是铬元素的优先溶解.

  20. Repairing sealing surfaces on aluminum castings

    Science.gov (United States)

    Hanna, T. L.

    1980-01-01

    Approach using stylus nickel plating instead of copper and cadmium plating has simplified repair procedure. Damaged sealing surfaces are stylus nickelplated in one step. Superficial scratches and porous areas are removed more easily from repaired surface by simply lapping sealing areas to required finish. Although method is aimed for aerospace components, it may be easily incorporated into conventional aluminumcasting technology. One-step repair can be considered for cast-aluminum automobile and aircraft engines to reduce time and costs.

  1. Effect of preparation methods of aluminum emulsions on catalytic performance of copper-based catalysts for methanol synthesis from syngas

    Institute of Scientific and Technical Information of China (English)

    Lili Wang; Wen Ding; Yingwei Liu; Weiping Fang; Yiquan Yang

    2010-01-01

    Various Cu/ZnO/Al2O3 catalysts have been synthesized by different aluminum emulsions as aluminum sources and their performances for methanol synthesis from syngas have been investigated.The influences of preparation methods of aluminum emulsions on physicochemical and catalytic properties of catalysts were studied by XRD,SEM,XPS,N2 adsorption-desorption techniques and methanol synthesis from syngas.The preparation methods of aluminum emulsions were found to influence the catalytic activity,CuO crystallite size,surface area and Cu0 surface area and reduction process.The results show that the catalyst CN using the aluminum source prepared by addition the ammonia into the aluminum nitrate (NP) exhibited the best catalytic performance for methanol synthesis from syngas.

  2. Surface Acidity of Amorphous Aluminum Hydroxide

    Institute of Scientific and Technical Information of China (English)

    K. FUKUSHI; K. TSUKIMURA; H. YAMADA

    2006-01-01

    The surface acidity of synthetic amorphous Al hydroxide was determined by acid/base titration with several complementary methods including solution analyses of the reacted solutions and XRD characterization of the reacted solids. The synthetic specimen was characterized to be the amorphous material showing four broad peaks in XRD pattern. XRD analyses of reacted solids after the titration experiments showed that amorphous Al hydroxide rapidly transformed to crystalline bayerite at the alkaline condition (pH>10). The solution analyses after and during the titration experiments showed that the solubility of amorphous aluminum hydroxide, Ksp =aAl3+/a3H+,was 1010.3,The amount of consumption of added acid or base during the titration experiment was attributed to both the protonation/deprotonation of dissolved Al species and surface hydroxyl group. The surface acidity constants, surface hydroxyl density and specific surface area were estimated by FITEQL 4.0.

  3. RF Magnetron Sputtering Aluminum Oxide Film for Surface Passivation on Crystalline Silicon Wafers

    Directory of Open Access Journals (Sweden)

    Siming Chen

    2013-01-01

    Full Text Available Aluminum oxide films were deposited on crystalline silicon substrates by reactive RF magnetron sputtering. The influences of the deposition parameters on the surface passivation, surface damage, optical properties, and composition of the films have been investigated. It is found that proper sputtering power and uniform magnetic field reduced the surface damage from the high-energy ion bombardment to the silicon wafers during the process and consequently decreased the interface trap density, resulting in the good surface passivation; relatively high refractive index of aluminum oxide film is benefic to improve the surface passivation. The negative-charged aluminum oxide film was then successfully prepared. The surface passivation performance was further improved after postannealing by formation of an SiOx interfacial layer. It is demonstrated that the reactive sputtering is an effective technique of fabricating aluminum oxide surface passivation film for low-cost high-efficiency crystalline silicon solar cells.

  4. Fabrication of superhydrophobic nanostructured surface on aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Jafari, R.; Farzaneh, M. [Universite du Quebec a Chicoutimi, Chicoutimi, QC (Canada)

    2011-01-15

    A superhydrophobic surface was prepared by consecutive immersion in boiling water and sputtering of polytetrafluoroethylene (PTFE or Teflon registered) on the surface of an aluminum alloy substrate. Immersion in boiling water was used to create a micro-nanostructure on the alloy substrate. Then, the rough surface was coated with RF-sputtered Teflon film. The immersion time in boiling water plays an important role in surface morphology and water repellency of the deposited Teflon coating. Scanning electron microscopy images showed a ''flower-like'' structure in first few minutes of immersion. And as the immersion time lengthened, a ''cornflake'' structure appeared. FTIR analyses of Teflon-like coating deposited on water treated aluminum alloy surfaces showed fluorinated groups, which effectively reduce surface energy. The Teflon-like coating deposited on a rough surface achieved with five-minute immersion in boiling water provided a high static contact angle ({proportional_to}164 ) and low contact angle hysteresis ({proportional_to}4 ). (orig.)

  5. Ultralyophobic oxidized aluminum surfaces exhibiting negligible contact angle hysteresis.

    Science.gov (United States)

    Hozumi, Atsushi; McCarthy, Thomas J

    2010-02-16

    Ultralyophobic oxidized aluminum surfaces exhibiting negligible contact angle hysteresis for probe liquids were prepared by chemical vapor deposition (CVD) of bis((tridecafluoro-1,1,2,2,-tetrahydrooctyl)-dimethylsiloxy)methylsilane (CF(3)(CF(2))(5)CH(2)CH(2)Si(CH(3))(2)O)(2)SiCH(3)H, (R(F)Si(Me)(2)O)(2)SiMeH). Oxidized aluminum surfaces were prepared by photooxidation/cleaning of sputter-coated aluminum on silicon wafers (Si/Al(Al(2)(O(3)))) using oxygen plasma. X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) confirmed that this facile CVD method produces a monolayer with a thickness of 1.1 nm on the Si/Al(Al(2)(O(3))) surface without a discernible change in surface morphology. After monolayer deposition, the hydrophilic Si/Al(Al(2)(O(3))) surface became both hydrophobic and oleophobic and exhibited essentially no contact angle hysteresis for water and n-hexadecane (advancing/receding contact angles (theta(A)/theta(R)) = 110 degrees/109 degrees and 52 degrees/50 degrees, respectively). Droplets move very easily on this surface and roll off of slightly tilted surfaces, independently of the contact angle (which is a practical definition of ultralyophobic). A conventional fluoroalkylsilane monolayer was also prepared from 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (CF(3)(CF(2))(7)CH(2)CH(2)Si(OCH(3))(3), R(F)Si(OMe)(3)) for comparison. The theta(A)/theta(R) values for water and n-hexadecane are 121 degrees/106 degrees and 76 degrees/71 degrees, respectively. The larger hysteresis values indicate the "pinning" of probe liquids, even though advancing contact angles are larger than those of the (R(F)Si(Me)(2)O)(2)SiMeH-derived monolayers. The (R(F)Si(Me)(2)O)(2)SiMeH-derived monolayers have excellent hydrolytic stability in water. We propose that the (R(F)Si(Me)(2)O)(2)SiMeH-derived monolayers are flexible and liquidlike and that drops in contact with these surfaces experience very low energy barriers between metastable states, leading to the

  6. Preparation of Aluminum Nanomesh Thin Films from an Anodic Aluminum Oxide Template as Transparent Conductive Electrodes

    Science.gov (United States)

    Li, Yiwen; Chen, Yulong; Qiu, Mingxia; Yu, Hongyu; Zhang, Xinhai; Sun, Xiao Wei; Chen, Rui

    2016-02-01

    We have employed anodic aluminum oxide as a template to prepare ultrathin, transparent, and conducting Al films with a unique nanomesh structure for transparent conductive electrodes. The anodic aluminum oxide template is obtained through direct anodization of a sputtered Al layer on a glass substrate, and subsequent wet etching creates the nanomesh metallic film. The optical and conductive properties are greatly influenced by experimental conditions. By tuning the anodizing time, transparent electrodes with appropriate optical transmittance and sheet resistance have been obtained. The results demonstrate that our proposed strategy can serve as a potential method to fabricate low-cost TCEs to replace conventional indium tin oxide materials.

  7. Radiolysis of water with aluminum oxide surfaces

    Science.gov (United States)

    Reiff, Sarah C.; LaVerne, Jay A.

    2017-02-01

    Aluminum oxide, Al2O3, nanoparticles with water were irradiated with γ-rays and 5 MeV He ions followed by the determination of the production of molecular hydrogen, H2, and characterization of changes in the particle surface. Surface analysis techniques included: diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), nitrogen absorption with the Brunauer - Emmett - Teller (BET) methodology for surface area determination, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Production of H2 by γ-ray radiolysis was determined for samples with adsorbed water and for Al2O3 - water slurries. For Al2O3 samples with adsorbed water, the radiation chemical yield of H2 was measured as 80±20 molecules/100 eV (1 molecule/100 eV=1.04×10-7 mol/J). The yield of H2 was observed to decrease as the amount of water present in the Al2O3 - water slurries increased. Surface studies indicated that the α-phase Al2O3 samples changed phase following irradiation by He ions, and that the oxyhydroxide layer, present on the pristine sample, is removed by γ-ray and He ion irradiation.

  8. Nanoengineered Superhydrophobic Surfaces of Aluminum with Extremely Low Bacterial Adhesivity

    NARCIS (Netherlands)

    Hizal, Ferdi; Rungraeng, Natthakan; Lee, Junghoon; Jun, Soojin; Busscher, Henk J.; van der Mei, Henny C.; Choi, Chang-Hwan

    2017-01-01

    Bacterial adhesion and biofilm formation on surfaces are troublesome in many industrial processes. Here, nanoporous and nanopillared aluminum surfaces were engineered by anodizing and postetching processes and made hydrophilic (using the inherent oxide layer) or hydrophobic (applying a Teflon

  9. Preparation of cast aluminum alloy-mica particle composites

    Science.gov (United States)

    Deonath, MR.; Bhat, R. T.; Rohatgi, P. K.

    1980-01-01

    A method for making aluminum-mica particle composites is presented in which mica particles are stirred in molten aluminum alloys followed by casting in permanent molds. Magnesium is added either as an alloying element or in the form of pieces to the surface of the alloy melts to disperse up to 3 wt% mica powders in the melts and to obtain high recoveries of mica in the castings. The mechanical properties of the aluminum alloy-mica composite decrease with increasing mica content; however, even at 2.2% it has a tensile strength of 14.22 kg/sq mm with 1.1% elongation, a compression strength of 42.61 kg/sq mm, and an impact strength of 0.30 kgm/sq cm. Cryogenic and self-lubricating bearing are mentioned applications.

  10. Preparation of cast aluminum alloy-mica particle composites

    Science.gov (United States)

    Deonath, MR.; Bhat, R. T.; Rohatgi, P. K.

    1980-01-01

    A method for making aluminum-mica particle composites is presented in which mica particles are stirred in molten aluminum alloys followed by casting in permanent molds. Magnesium is added either as an alloying element or in the form of pieces to the surface of the alloy melts to disperse up to 3 wt% mica powders in the melts and to obtain high recoveries of mica in the castings. The mechanical properties of the aluminum alloy-mica composite decrease with increasing mica content; however, even at 2.2% it has a tensile strength of 14.22 kg/sq mm with 1.1% elongation, a compression strength of 42.61 kg/sq mm, and an impact strength of 0.30 kgm/sq cm. Cryogenic and self-lubricating bearing are mentioned applications.

  11. A liquid aluminum corrosion resistance surface on steel substrate

    Energy Technology Data Exchange (ETDEWEB)

    Wang Deqing; Shi Ziyuan; Zou Longjiang

    2003-05-31

    The process of hot dipping pure aluminum on a steel substrate followed by oxidation was studied to form a surface layer of aluminum oxide resistant to the corrosion of aluminum melt. The thickness of the pure aluminum layer on the steel substrate is reduced with the increase in temperature and time in initial aluminizing, and the thickness of the aluminum layer does not increase with time at given temperature when identical temperature and complete wetting occur between liquid aluminum and the substrate surface. The thickness of the Fe-Al intermetallic layer on the steel base is increased with increasing bath temperature and time. Based on the experimental data and the mathematics model developed by the study, a maximum exists in the thickness of the Fe-Al intermetallic at certain dipping temperature. X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analysis reveals that the top portion of the steel substrate is composed of a thin layer of {alpha}-Al{sub 2}O{sub 3}, followed by a thinner layer of FeAl{sub 3}, and then a much thicker one of Fe{sub 2}Al{sub 5} on the steel base side. In addition, there is a carbon enrichment zone in diffusion front. The aluminum oxide surface formed on the steel substrate is in perfect condition after corrosion test in liquid aluminum at 750 deg. C for 240 h, showing extremely good resistance to aluminum melt corrosion.

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

    Energy Technology Data Exchange (ETDEWEB)

    Saleema, N., E-mail: saleema.noormohammed@imi.cnrc-nrc.gc.ca [National Research Council of Canada (ATC-NRC), 501 Boulevard University East, Saguenay, Quebec G7H 8C3 (Canada); Sarkar, D.K. [Centre Universitaire de Recherche sur l' Aluminium (CURAL), University of Quebec at Chicoutimi (UQAC), 555 Boulevard University East, Saguenay, Quebec G7H 2B1 (Canada); Paynter, R.W. [Institut National de la Recherche Scientifique Energie Materiaux Telecommunications (INRS-EMT), 1650 Boulevard Lionel-Boulet, Varennes, Quebec J3X 1S2 (Canada); Gallant, D.; Eskandarian, M. [National Research Council of Canada (ATC-NRC), 501 Boulevard University East, Saguenay, Quebec G7H 8C3 (Canada)

    2012-11-15

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

  13. Advanced metrology of surface defects measurement for aluminum die casting

    Directory of Open Access Journals (Sweden)

    D. Myszka

    2011-07-01

    Full Text Available The scientific objective of the research is to develop a strategy to build computer based vision systems for inspection of surface defects inproducts, especially discontinuities which appear in castings after machining. In addition to the proposed vision inspection method theauthors demonstrates the development of the advanced computer techniques based on the methods of scanning to measure topography ofsurface defect in offline process control. This method allow to identify a mechanism responsible for the formation of casting defects. Also,the method allow investigating if the, developed vision inspection system for identification of surface defects have been correctlyimplemented for an online inspection. Finally, in order to make casting samples with gas and shrinkage porosity defects type, the LGT gas meter was used . For this task a special camera for a semi-quantitative assessment of the gas content in aluminum alloy melts, using a Straube-Pfeiffer method was used. The results demonstrate that applied solution is excellent tool in preparing for various aluminum alloysthe reference porosity samples, identified next by the computer inspection system.

  14. Novel foaming agent used in preparation process of aluminum foams

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The performances of a novel foaming agent used in the preparation process of aluminum foams were investigated,and the effects of some factors,such as addition of the foaming agent,foaming temperature on the porosity,and appearance of aluminum foams were also discussed.Experimental results show that the novel foaming agent has a wide decomposition temperature range and a mild decomposed rate; the foaming agent has the ability to enhance the viscosity of aluminum melt,as a result,an extra viscosifier such as Ca or SiCp is unnecessary while using this foaming agent; the bubble-free zone in material decreases and the foaming efficiency increases with the increase of foaming agent; the bubble-free zone disappears and the foaming efficiency is near 100% when the addition of foaming agent is more than 1.4wt% ; the porosity of the aluminum foam increases with the increase of foaming agent when the addition of foaming agent is less than 2.2wt% .

  15. Antibody immobilization on a nanoporous aluminum surface for immunosensor development

    Science.gov (United States)

    Chai, Changhoon; Lee, Jooyoung; Park, Jiyong; Takhistov, Paul

    2012-12-01

    A method of antibody (Ab) immobilization on a nanoporous aluminum surface for an electrochemical immunosensor is presented. To achieve good attachment and stability of Ab on an aluminum surface, aluminum was silanized with 3-aminopropyltryethoxysilane (APTES), and then covalently cross-linked to self-assembled layers (SALs) of APTES. Both the APTES concentration and the silanization time affected the formation of APTES-SALs as Ab immobilization. The formation of APTES-SALs was confirmed using the water contact angle on the APTES-SALs surface. The reactivity of APTES-SALs with Ab was investigated by measuring the fluorescence intensity of fluorescein isothiocyanate-labeled Ab-immobilized on the aluminum surface. Silanization of aluminum in 2% APTES for 4 h resulted in higher water contact angles and greater amounts of immobilized Ab than other APTES concentrations or silanization times. More Ab was immobilized on the nanoporous surface than on a planar aluminum surface. Electrochemical immunosensors developed on the nanoporous aluminum via the Ab immobilization method established in this study responded functionally to the antigen concentration in the diagnostic solution.

  16. Environmental dust effects on aluminum surfaces in humid air ambient

    Science.gov (United States)

    Yilbas, Bekir Sami; Hassan, Ghassan; Ali, Haider; Al-Aqeeli, Nasser

    2017-01-01

    Environmental dusts settle on surfaces and influence the performance of concentrated solar energy harvesting devices, such as aluminum troughs. The characteristics of environmental dust and the effects of mud formed from the dust particles as a result of water condensing in humid air conditions on an aluminum wafer surface are examined. The dissolution of alkaline and alkaline earth compounds in water condensate form a chemically active mud liquid with pH 8.2. Due to gravity, the mud liquid settles at the interface of the mud and the aluminum surface while forming locally scattered patches of liquid films. Once the mud liquid dries, adhesion work to remove the dry mud increases significantly. The mud liquid gives rise to the formation of pinholes and local pit sites on the aluminum surface. Morphological changes due to pit sites and residues of the dry mud on the aluminum surface lower the surface reflection after the removal of the dry mud from the surface. The characteristics of the aluminum surface can address the dust/mud-related limitations of reflective surfaces and may have implications for the reductions in the efficiencies of solar concentrated power systems. PMID:28378798

  17. Chemical milling solution produces smooth surface finish on aluminum

    Science.gov (United States)

    Lorenzen, H. C.

    1966-01-01

    Elementary sulfur mixed into a solution of caustic soda and salts produces an etchant which will chemically mill end-grain surfaces on aluminum plate. This composition results in the least amount of thickness variation and pitting.

  18. LC4铝合金表面硬质阳极氧化膜制备及表征%Preparation and Characterization of Hard Anodic Oxidation Film on LC4 Aluminum Alloy Surface

    Institute of Scientific and Technical Information of China (English)

    王英才; 陈岁元; 刘平平

    2014-01-01

    目的:在 LC4铝合金表面制备硬质阳极氧化膜,讨论工艺参数对膜层厚度和硬度的影响。方法对阳极氧化的时间、温度、电流密度及正负脉冲电流时间比等参数进行优化实验,通过 OM,SEM,XRD 及显微硬度计等对制备的氧化膜层的厚度、硬度、形貌等进行研究。结果工艺优化后的参数为:温度-2~0℃,正脉冲电流密度4 A/ dm2,负脉冲电流密度1 A/ dm2,正负脉冲电流时间比6:1,氧化时间50 min。得到由一系列直径约为50 nm 的管状单元结构组成的氧化膜,其厚度为36μm,硬度为420HV。结论制备的阳极氧化膜具有致密的组织结构和高的硬度值。%Objective The hard anodic oxidation films were prepared on the surface of the LC4 aluminum alloy and the effects of different parameters on the thickness and hardness of the films were discussed. Methods By optimizing parameters of the anodic ox-idation time, temperature, current density and the positive and negative pulse time ratio, the thickness, hardness and microstruc-ture of the films were studied by means of OM, SEM, XRD, and hardness tester. Results The optimized parameters were: a tem-perature of -2 ~ 0 ℃ , a positive pulse current density of 4 A/ dm2 , a negative pulse current density of 1 A/ dm2 , a positive and negative pulse current time ratio of 6 : 1, and an oxidation time of 50 min. The structure of the oxide film on LC4 aluminum alloy was composed of a series of tubular cells with a diameter of 50 nm, the thickness of anodic oxidation film was 36 μm, and the hard-ness was 420HV. Conclusion The anodic oxidation film had fine structure and high hardness.

  19. Engineering wear-resistant surfaces in automotive aluminum

    Science.gov (United States)

    Kavorkijan, V.

    2003-02-01

    Inadequate wear resistance and low seizure loads prevent the direct use of aluminum alloys in automotive parts subject to intensive friction combined with high thermal and mechanical loading, such as brake discs, pistons, and cylinder liners. To enable the use of aluminum alloys in the production of automotive brake discs and other wear-resistant products, the insertion of a monolithic friction cladding rather than surface coating has been considered in this work. Three experimental approaches, two based on the pressure-less infiltration of porous ceramic preforms and one based on the subsequent hot rolling of aluminum and metal-matrix composite strips, are currently under investigation.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2013-01-01

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

  2. Preparation of Ultra-fine Aluminum Nitride in Thermal Plasma

    Institute of Scientific and Technical Information of China (English)

    漆继红; 罗义文; 印永祥; 代晓雁

    2002-01-01

    Ultra-fine aluminum nitride has been synthesized by the evaporation of aluminum powder at atmospheric-pressure nitrogen plasma in a hot-wall reactor. The average size of aluminum nitride particle is 0.11μm measured by scanning electric mirror (SEM), and the purity is at least over 90% evaluated by X-Ray diffraction (XRD). The conversion of Al powder to aluminum nitride is strongly depended on the injection of NH3. Typical experimental parameters such as the feed rate of raw material, the flow rate of ammonia and the position of injecting aluminum powder into the reactor are given.

  3. Testing the performance of superhydrophobic aluminum surfaces.

    Science.gov (United States)

    Ruiz-Cabello, F Javier Montes; Ibáñez-Ibáñez, Pablo F; Gómez-Lopera, J Francisco; Martínez-Aroza, José; Cabrerizo-Vílchez, Miguel; Rodríguez-Valverde, Miguel A

    2017-12-15

    The analysis of wetting properties of superhydrophobic surfaces may be a difficult task due to the restless behavior of drops on this type of surfaces and the limitations of goniometry for high contact angles. A method to validate the performance of superhydrophobic surfaces, rather than standard goniometry, is required. In this work, we used bouncing drop dynamics as a useful tool to predict the water repellency of different superhydrophobic surfaces. From bouncing drop experiments conducted over a wide range of superhydrophobic surfaces, we found that those surfaces with a proper roughness degree and homogeneous chemical composition showed higher water-repellency. We also conducted a drop condensation study at saturating conditions aimed to determine whether there is direct correlation between water repellency and condensation delay. We found that the drop condensation process is strongly related to the surface topography, as well as the intrinsic wettability. The condensation is promoted on rough surfaces but it is delayed on intrinsically hydrophobic surfaces. However, the differences found in condensation delay between the superhydrophobic surfaces explored in this study cannot be justified by their chemical homogeneity nor their efficiency as water repellent surfaces, separately. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Laser Surface Preparation and Bonding of Aerospace Structural Composites

    Science.gov (United States)

    Belcher, M. A.; Wohl, C. J.; Hopkins, J. W.; Connell, J. W.

    2010-01-01

    Adhesive bonds are critical to the integrity of built-up structures. Disbonds can often be detected but the strength of adhesion between surfaces in contact is not obtainable without destructive testing. Typically the number one problem in a bonded structure is surface contamination, and by extension, surface preparation. Standard surface preparation techniques, including grit blasting, manual abrasion, and peel ply, are not ideal because of variations in their application. Etching of carbon fiber reinforced plastic (CFRP) panels using a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser appears to be a highly precise and promising way to both clean a composite surface prior to bonding and provide a bond-promoting patterned surface akin to peel ply without the inherent drawbacks from the same (i.e., debris and curvature). CFRP surfaces prepared using laser patterns conducive to adhesive bonding were compared to typical prebonding surface treatments through optical microscopy, contact angle goniometry, and post-bonding mechanical testing.

  5. Disordering and Melting of Aluminum Surfaces

    DEFF Research Database (Denmark)

    Stoltze, Per; Nørskov, Jens Kehlet; Landman, U.

    1988-01-01

    We report on a molecular-dynamics simulation of an Al(110) surface using the effective-medium theory to describe the interatomic interactions. The surface region is found to start melting ≅200 K below the bulk melting temperature with a gradual increase in the thickness of the disordered layer as...

  6. Surface quality of cold rolling aluminum strips under lubrication condition

    Institute of Scientific and Technical Information of China (English)

    Jianlin Sun; Wang Lu; Yanli Ma; Qingbing Shi; Aihua Zhang; Jian Li

    2008-01-01

    The effects of oil fill on the rolled surface, including surface roughness and topography, were investigated during cold rolling of aluminum strips. Various mineral oils with viscosities from 0.10 to 1.6 Pa.s were used to obtain different oil film thick-nesses. Results from experiment and calculation show that the thicker oil film protects the initial roughening surface so that it leads to an increase in roughness of the rolled surface, in particular when the surface roughness has the character of direction. The rolled surface roughness was determined by λ, which is the ratio of oil film thickness to the combined surface roughness. When λ > 3, the rolled surface roughness increases rapidly with the increase in oil viscosity, whereas the surface roughening has already occurred when λ < 3, but the increase of the rolled surface roughness with increasing viscosity is not distinct.

  7. Influence of Surface Roughness on Morphology of Aluminum Alloy After Pulsed-Laser Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sung Ho; Kim, Chung Seok; Jhang, Kyung Young [Hanyang University, Seoul (Korea, Republic of); Shin, Wan Soon [Agency for Defense Development, Daejeon (Korea, Republic of)

    2011-09-15

    The objective of this study is to investigate the influence of surface roughness on the morphology of aluminum 6061- T6 alloy after irradiation with a Nd:YAG pulsed laser. The test specimen was prepared by a polishing process using a diamond paste (1 {mu}m) and emery polishing papers (100, 220, 600, 2400) to obtain different initial surface roughness. After irradiation with ten pulsed-laser shots, the surface morphology was examined by using scanning electron microscopy (SEM), optical microscopy (OM), and atomic force microscopy (AFM). The diameter of the melted zone increased with the surface roughness because the multiple reflections and absorption of the laser beam occurred on the surface because of the surface roughness, so that the absorptance of the laser beam changed. This result was verified using the relative absorptance calculated from the diameter of the melted zone with the surface roughness and the diameter increased with the average surface roughness.

  8. Dynamic wetting of ro1ling oil on aluminum surfaces

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ya-jun; ZHOU Hong-hui

    2007-01-01

    Static and dynamic contact angles of stock oil and its solutions with additives(fatty acid, fatty alcohol, fatty methyl ester usually used in rolling aluminum) were measured on aluminum surface (Alloy 1145) by sessile drop technique on an OCA35 dynamic contact angle tester. The effect of additive on the drop spreading was investigated as well. It is shown that the drop spreads very quickly in the first 500 ms after the lubricant contacts with the aluminum surface, and then does slowly later. The dynamic contact angle decreases exponentially with time. In contrast to the stock oil, although addition of polarity additive of long chain alkyl into stock oil is able to decrease the surface tension of solutions, it weakens the wetting dynamic, which results from the adsorption at the expanding solid/liquid interface. Among the same long chain polarity organic compounds used, dynamic wetting decreases in the order of fatty acid, fatty alcohol and fatty ester. The blend of fatty alcohol and fatty methyl ester can improve the oil wetting dynamics and promote the lubricant spreading.

  9. A study of Corrosion Protection of Aluminum Metal by Tetraethoxysilane Plasma Polymerized Coatings-Influence of Aluminum Surface Pretreatments-

    Institute of Scientific and Technical Information of China (English)

    YoshihiroMomose; TatsuyaYabuki

    2004-01-01

    The corrosion-protective performance of plasma-polymerized (PP) coatings on pretreated aluminum substrates has been investigated by cathodic polarization curve measurement. The surface composition and electronic properties of the pretreated and PP film coated metal surfaces were also characterized by XPS and the temperature-programmed photoelectron emission (TPPE). A PP coating was prepared on the pretreated surfaces by plasma polymerization of a mixture of tetraethoxysilane (TEOS) monomer vapor and oxygen using a 13.56MHz radiofrequency generator. The polarization curve of PP film coated samples was measured in NaC1 aqueous solution. The weight loss rate calculated from the value of the corrosion current of the curve was used to estimate the protective performance of the PP film coated samples. Argon plasma treatment of the metal surface gave much better corrosion-protective performance than pretreatments such as oxidation by heating in air and diamond scratching. The XPS analysis indicated that the silicon oxide assigned to SiO2 was formed on the PP film coated surface. The TPPE analysis revealed that the electron emission characteristics for the metal surfaces pretreated only were strongly influenced by the pretreatments, while all the PP film coated samples exhibited nearly the same electron emission trend with a much decreased intensity.

  10. A study of Corrosion Protection of Aluminum Metal by Tetraethoxysilane Plasma Polymerized Coatings -Influence of Aluminum Surface Pretreatments-

    Institute of Scientific and Technical Information of China (English)

    Yoshihiro Momose; Tatsuya Yabuki

    2004-01-01

    The corrosion-protective performance of plasma-polymerized (PP) coatings on pretreated aluminum substrates has been investigated by cathodic polarization curve measurement. The surface composition and electronic properties of the pretreated and PP film coated metal surfaces were also characterized by XPS and the temperature-programmed photoelectron emission (TPPE). A PP coating was prepared on the pretreated surfaces by plasma polymerization of a mixture of tetraethoxysilane (TEOS) monomer vapor and oxygen using a 13.56MHz radiofrequency generator. The polarization curve of PP film coated samples was measured in NaCl aqueous solution. The weight loss rate calculated from the value of the corrosion current of the curve was used to estimate the protective performance of the PP film coated samples. Argon plasma treatment of the metal surface gave much better corrosion-protective performance than pretreatments such as oxidation by heating in air and diamond scratching. The XPS analysis indicated that the silicon oxide assigned to SiO2 was formed on the PP film coated surface. The TPPE analysis revealed that the electron emission characteristics for the metal surfaces pretreated only were strongly influenced by the pretreatments, while all the PP film coated samples exhibited nearly the same electron emission trend with a much decreased intensity.

  11. Advances in aluminum anodizing

    Science.gov (United States)

    Dale, K. H.

    1969-01-01

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

  12. Surface Roughening Behavior of 6063 Aluminum Alloy during Bulging by Spun Tubes

    Directory of Open Access Journals (Sweden)

    Yang Cai

    2017-03-01

    Full Text Available Severe surface roughening during the hydroforming of aluminum alloy parts can produce surface defects that severely restrict their application in the automobile and aerospace industry. To understand the relation between strain, grain size and surface roughness under biaxial stress conditions, hydro-bulging tests of aluminum alloy tubes were carried out, and the tubes with different grain sizes were prepared by a spinning and annealing process. The surface roughness was measured by a laser scanning confocal microscope to evaluate the surface roughening macroscopical behavior, and the corresponding microstructures were observed using electron back-scattered diffraction (EBSD to reveal the roughening microscopic behavior. The results obtained show that the surface roughness increased with both strain and grain size under biaxial stress. No surface defects were observed on the surface when the grain size was less than 105 μm if the strain was less than 18%, or when the grain size was between 130 and 175 μm if the strain was less than 15.88% and 7.15%, respectively. The surface roughening microscopic behavior was identified as an inhomogeneous grain size distribution, which became more pronounced with increasing grain size and resulted in greater local deformation. Concentrated grain orientation also results in severe inhomogeneous deformation during plastics deformation, and serious surface roughening.

  13. Advances on aluminum first-surface solar reflectors

    Science.gov (United States)

    Almanza, Rafael; Chen, Jiefeng; Mazari, Marcos

    1992-11-01

    Aluminum first surface mirrors have some advantages over second surface mirrors as has been discussed. At this stage of development some advantages are obtained: the first advantage was using two electron guns, one for aluminum evaporation permitting us to eliminate or to minimize the pinholes and the other to allow the evaporation of SiO without any mirror contamination as it was before due to the air when the chamber was opened to introduce the SiO, despite having only one e-gun in the laboratory. The second advantage was a better adherence between the aluminum film and the Si2O3, this last substance obtained with an oxidation of SiO with some oxygen inside the evaporation chamber (10-4 Torr). This improvement was due to the use of two e-guns that permit us not to open the chamber. These mirrors are actually under test in the environmental chamber for accelerated weather evaluations. One important aspect is the cleaning of the glass substrate. The chromic mixture cleaning is one of the most effective.

  14. Evaluation of microstructure of A356 aluminum alloy casting prepared under vibratory conditions during the solidification

    Indian Academy of Sciences (India)

    SAKENDRA KUMAR; S P TEWARI

    2016-10-01

    The objective of this investigation was to evaluate the effect of vibrations (during solidification) on the metallurgical properties of A356 aluminum casting. Mechanical vibrations were applied to A356 aluminum alloy through set up. A356 melt has been subjected to mechanical vibration with the frequency range from 0 to 400 Hz with constant amplitude 5 lm. Grain refinement was obtained through mold vibration. Metallurgical properties were examined through optical microstructure, tensile fracture scanning electron microscope (SEM) and SEM image of test specimens prepared under different conditions of solidification. Results indicate that mold vibration effectively modified the microstructure of A356 casting and it has uniform and smaller grain sizewith fibrous silicon particle than nonvibrated casting. Grain refinement results increase in mechanical properties with increase in frequency of vibration of mold during the solidification. SEM micrograph of tensile fracture surface was carried out to study the influence of microstructure on fracture mode. SEM image of tensile fractured surface shows transgranular cleavage facets due to fracture of primary silicon particles. Fractures are brittle in nature so observation indicates low ductility and brittle fracture.

  15. Fabrication and anti-icing property of coral-like superhydrophobic aluminum surface

    Science.gov (United States)

    Zuo, Zhiping; Liao, Ruijin; Guo, Chao; Yuan, Yuan; Zhao, Xuetong; Zhuang, Aoyun; Zhang, YiYi

    2015-03-01

    Aluminum is one of the most widely used metals in transmission lines. Accumulation of ice on aluminum may cause serious consequences such as tower collapse and power failure. Here we develop a method to fabricate a coral-like superhydrophobic surface to improve its anti-icing performance via chemical etching and hot-water treatment. The as-prepared surface exhibited superhydrophobicity with a contact angle (CA) of 164.8 ± 1.1° and the sliding angle smaller than 1°. The static and dynamic anti-icing behaviors of the superhydrophobic surface in different conditions were systematically investigated using a self-made device and artificial climate laboratory. Results show that the coral-like superhydrophobic structure displayed excellent anti-icing property. The water droplet remained unfrozen on the as-prepared surface at -6 °C for over 110 min. 71% of the surface was free of ice when exposed in "glaze ice" for 30 min. This investigation proposed a new way to design an anti-icing surface which may have potential future applications in transmission lines against ice accumulation.

  16. Investigation of aluminum surface cleaning using cavitating fluid flow

    Energy Technology Data Exchange (ETDEWEB)

    Ralys, Aurimas; Striška, Vytautas; Mokšin, Vadim [Vilnius Gediminas Technical University, Faculty of Mechanics, Department of Machine Engineering, J. Basanavičiaus str.28, 03224, Vilnius (Lithuania)

    2013-12-16

    This paper investigates efficiency of specially designed atomizer used to spray water and cavitate microbubbles in water flow. Surface cleaning system was used to clean machined (grinded) aluminum surface from abrasive particles. It is established that cleaning efficiency depends on diameter of the diffuser, water pressure and distance between nozzle and metal surface. It is obtained that the best cleaning efficiency (100%) is achieved at pressure 36 bar, when diameter of diffuser is 0.4 mm and distance between nozzle and surface is 1 mm. It is also established that satisfactory cleaning efficiency (80%) is achieved not only when atomizer is placed closer to metal surface, but also at larger (120 mm) distances.

  17. Roughness of surface of vacuum castings prepared in plaster moulds

    Directory of Open Access Journals (Sweden)

    M. Pawlak

    2011-07-01

    Full Text Available The results of researches on surface roughness of CuSn10 and CuSn5Zn5Pb5 bronzes and aluminum AlSi11 alloy vacuum castings prepared in plaster moulds are presented in this paper. Test samples were cut from stripe castings of dimensions 100x15x1 mm. Surfaces were carefully cleaned with use of soft brush than in ultrasonic washer and dried. Experimental castings were prepared in moulds made of two types of plaster. Cast temperatures were 1120 and 1200°C for bronzes and 700 and 800°C for silumin. Temperatures of the mould were 500 and 600°C for bronzes and 200 and 300°C for aluminum alloy. The roughness measurements were carried out with use of Hommelwerke Tester T1000. The average arithmetic deviation of roughness profile Ra, the ten-point height of irregularities Rz and maximum peak to valley height Rm, were measured.It can be stated, on the base of obtained results, that technology of casting in plaster moulds allows preparation of castings of very low roughness, average Ra=0,88÷1,74μm for bronzes and Ra=0,59÷0,83μm for aluminum alloys. Roughness of the surface depends in fact on the cast material. Type of plaster and casting parameters have negligible influence on it.

  18. Method of surface preparation of niobium

    Science.gov (United States)

    Srinivasan-Rao, Triveni; Schill, John F.

    2003-01-01

    The present invention is for a method of preparing a surface of niobium. The preparation method includes polishing, cleaning, baking and irradiating the niobium surface whereby the resulting niobium surface has a high quantum efficiency.

  19. Surface characteristics of aluminum 6061 T6 subjected to Nd:YAG pulsed laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sung Ho; Kim, Chung Seok; Jhang, Kyung Young; Shin, Wan Soon [Hanyang University, Seoul (Korea, Republic of)

    2012-07-15

    The objective of this study was to investigate the surface characteristics of an aluminum 6061 T6 alloy subjected to Nd:YAG pulsedlaser irradiation. The test specimens were prepared by a mechanical polishing process using diamond paste and emery polishing paper to obtain different levels of initial surface roughness. After ten pulsed laser shots, the surface morphology was observed via optical microscopy (OM) and scanning electron microscopy (SEM). Nano indentation hardness testing was also conducted on the irradiated surface. The diameter of the melted zone increased with surface roughness because of the multiple reflection and absorption of the laser beam. The relative absorbance was measured as a function of the diameter of the melted zone with varied surface roughness.

  20. Investigations on reducing microbiologically-influenced corrosion of aluminum by using super-hydrophobic surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Liu Tao, E-mail: liutao@shmtu.edu.c [Institute of Marine Materials Science and Engineering, Shanghai Maritime University, Shanghai 201306 (China); Dong Lihua; Liu Tong; Yin Yansheng [Institute of Marine Materials Science and Engineering, Shanghai Maritime University, Shanghai 201306 (China)

    2010-07-15

    Electrochemical impedance spectroscopy, potentiodynamic polarization and scanning electron microscopy were carried out to determine the effect of super-hydrophobic surfaces on the marine bacterium Vibrio natriegens (V. natriegens) adhesion. Four different samples were prepared in order to investigate the anti-biocorrosion mechanism of super-hydrophobic surfaces. Potentiodynamic polarization suggested that the V. natriegens attached on the surface mainly enhanced the reaction kinetics of the anodic reaction and accelerated the dissolution of aluminum. EIS results were interpreted with different equivalent circuits to model the physicoelectric characteristics of the electrode/biofilm/solution interface. The results showed that neither anodization nor chemical modification could decrease the bacterial adhesion and corrosion rate individually. V. natriegens showed only weak attachment to the super-hydrophobic surface, and the biocorrosion mechanism was closely associated with surface energy and surface topography.

  1. Preparation and characterization of energetic materials coated superfine aluminum particles

    Science.gov (United States)

    Liu, Songsong; Ye, Mingquan; Han, Aijun; Chen, Xin

    2014-01-01

    This work is devoted to protect the activity of aluminum in solid rocket propellants by means of solvent/non-solvent method in which nitrocellulose (NC) and Double-11 (shortened form of double-base gun propellant, model 11) have been used as coating materials. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize the morphology of coated Al particles. Other characterization data of coated and uncoated Al particles, such as infrared absorption spectrum, laser particle size analysis and the active aluminum content were also studied. The thermal behavior of pure and coated aluminum samples have also been studied by simultaneous thermogravimetry-differential thermal analysis (TG-DTA) and differential scanning calorimetry (DSC). The results indicated that: superfine aluminum particles could be effectively coated with nitrocellulose and Double-11 through a solvent/non-solvent method. The energetic composite particles have core-shell structures and the thickness of the coating film is about 20-50 nm. The active aluminum content of different coated samples was measured by means of oxidation-reduction titration method. The results showed that after being stored in room temperature and under 50% humidity condition for about 4months the active aluminum content of coated Al particles decreased from 99.8 to 95.8% (NC coating) and 99.2% (Double-11 coating) respectively. Double-11 coating layer had a much better protective effect. The TG-DTA and DSC results showed that the energy amount and energy release rate of NC coated and Double-11 coated Al particles were larger than those of the raw Al particles. Double-11 coated Al particles have more significant catalytic effect on the thermal decomposition characters of AP than that of NC coated Al particles. These features accorded with the energy release characteristics of solid propellant.

  2. Preparation and characterization of energetic materials coated superfine aluminum particles

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Songsong; Ye, Mingquan, E-mail: liusong8366@gmail.com; Han, Aijun; Chen, Xin

    2014-01-01

    This work is devoted to protect the activity of aluminum in solid rocket propellants by means of solvent/non-solvent method in which nitrocellulose (NC) and Double-11 (shortened form of double-base gun propellant, model 11) have been used as coating materials. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize the morphology of coated Al particles. Other characterization data of coated and uncoated Al particles, such as infrared absorption spectrum, laser particle size analysis and the active aluminum content were also studied. The thermal behavior of pure and coated aluminum samples have also been studied by simultaneous thermogravimetry–differential thermal analysis (TG–DTA) and differential scanning calorimetry (DSC). The results indicated that: superfine aluminum particles could be effectively coated with nitrocellulose and Double-11 through a solvent/non-solvent method. The energetic composite particles have core-shell structures and the thickness of the coating film is about 20–50 nm. The active aluminum content of different coated samples was measured by means of oxidation–reduction titration method. The results showed that after being stored in room temperature and under 50% humidity condition for about 4months the active aluminum content of coated Al particles decreased from 99.8 to 95.8% (NC coating) and 99.2% (Double-11 coating) respectively. Double-11 coating layer had a much better protective effect. The TG–DTA and DSC results showed that the energy amount and energy release rate of NC coated and Double-11 coated Al particles were larger than those of the raw Al particles. Double-11 coated Al particles have more significant catalytic effect on the thermal decomposition characters of AP than that of NC coated Al particles. These features accorded with the energy release characteristics of solid propellant.

  3. Preparation of big size open-cell aluminum foam board using infiltration casting

    Institute of Scientific and Technical Information of China (English)

    Wang Lucai; Chen Yuyong; Wang Fang; Wu Jianguo; You Xiaohong

    2008-01-01

    This paper presents an infiltration casting technique for manufacturing big size open-cell aluminum foam boards. The principle and key technologies of infiltration casting are also analyzed. Based on the previous practice of the small size aluminum foam production, the die for preparing big size aluminum foam boards is designed and manufactured. The experiments on aluminum boards of 300 mm×300 mm×(20-75) mm, with the pore size ranging from 1.0 to 3.2 mm and average porosity of 60%, have been performed. The experimental results show that a reliable infiltration process depends critically on the pouring temperature of the molten AI-alloy, the preheated temperature of the mould and salt particles and vacuum. Current research explores the possibility of large-scale manufacturing and application of the aluminum foams.

  4. Composition and hardness of mullite coatings formed with direct current power supply on LY12 aluminum alloy surface

    Institute of Scientific and Technical Information of China (English)

    XIN Shi-gang; JIANG Zhao-hua; LI Yan-ping; ZHANG Ji-lin

    2005-01-01

    The surface modification of aluminum and its alloys using plasma technology is increasingly being investigated. Thick ceramic coatings with high hardness on aluminum alloys can be prepared successfully using a micro-plasma oxidation (MPO) technique. In this work, the composition, microstructure and elemental distribution of ceramic coatings formed by MPO on LY 12 aluminum alloy and its hardness are investigated using XRD, EPMA and microhardness instruments. The results show that the ceramic coatings consist of mullite, γ -Al2 O3 and a lot of amorphous matter. The content of silicon in the coatings increases from interface to the coatings, however, the content of aluminum decreases along this direction. The maximum hardness of ceramic coatings is up to 9. 2 GPa.

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

    Science.gov (United States)

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

    2013-03-01

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

  6. A novel photo-initiated approach for preparing aluminum diethylphosphinate under atmospheric pressure

    Institute of Scientific and Technical Information of China (English)

    Li Yang; Xin Yu Han; Xue Jiao Tang; Chang Xiu Han; Yi Xiao Zhou; Bao Gui Zhang

    2011-01-01

    A novel preparation of aluminum diethylphosphinate (AlPi) was carried out with free-radical addition reaction by means of UV-irradiation under atmospheric pressure. A solution of sodium hypophosphite was treated with ethylene and irradiated with ultraviolet light in the presence of an amount of photoinitiator effective to initiate the free-radical reaction between the hypophosphite anion and the double bond of the ethylene molecule. The ethylene was micro-bubbled into the reaction mixture with the addition of the photoinitiator, and the gas-liquid contact surface and the photoinitiator concentration in the gas-liquid interface were increased largely. The yield of the final product could be improved to about 96%. The contents of P, Al in samples were detected by ICP, and the molecular structure of the samples was confirmed by 31P NMR, 1H NMR and FTIR spectroscopic analysis. Thermal stability of the final products was investigated in detail by TG-DTA.

  7. 金属基底上高疏水性PVDF多孔膜的制备及性能研究∗%Properties and preparation of high hydrophobic PVDF porous membrane by non-solvent induced phase inversion using etched alloy aluminum surface as substrate

    Institute of Scientific and Technical Information of China (English)

    王志英; 吴晓君; 刘启东; 杨振生

    2014-01-01

    以聚偏氟乙烯(PVDF )/二甲基乙酰胺(DMAc)-正辛醇/水为制膜体系,以腐蚀的合金铝板为制膜基底,采用非溶剂致相转化法制膜,考察了粗糙金属基底对 PVDF 膜结构、性能及其结晶行为的影响。结果显示,金属基底的粗糙微结构对膜的锚固约束不仅减慢了溶剂-非溶剂的传质速率,而且对膜底面有诱导结晶效应;与在光滑基底上所制的 PVDF 膜相比,其膜底面的结晶度与表面粗糙度均增大,水接触角可达133°,且疏水性能稳定;与在砂纸基底上制备的高疏水PVDF膜相比,其气通量和机械强度均有提高。%Abstrac:Polyvinylidene fluoride (PVDF)membranes were fabricated by non-solvent induced phase inversion with the system of PVDF/N,N-dimethylacetamide(DMAc)and 1-octanol/water.DMAc and octanol were used as solvent and non-solvent addition,respectively.In this method,the polymer dope solution was cast on etched alloy aluminum template and the membrane was staying in an environment of constant temperature and relative humidity was about 90% for a certain time.Then it was immersed into water coagulation bath.Effects of the substrate on morphology,performance and crystallization of PVDF membrane were investigated.It was found that the crystallinity and roughness of membrane bottom surface increased which was tailored on etched alloy a-luminum template compared to that on smooth glass sheet.The water contact angle on the bottom surface of the membrane prepared on etched alloy aluminum template reached as high as 133°and the hydrophobicity was stable with time.It was revealed that the membrane could be anchored to the alloy aluminum template,so that the mass transfer rate between solvent and nonsolvent decreased and liquid-solid demixing was promoted.The micrometer-sized morphology of etched alloy aluminum substrate provided induced crystallization.The above-mentioned opinions were confirmed by wide-angle X-ray scattering

  8. Complex rare-earth aluminum hydrides: mechanochemical preparation, crystal structure and potential for hydrogen storage.

    Science.gov (United States)

    Weidenthaler, Claudia; Pommerin, André; Felderhoff, Michael; Sun, Wenhao; Wolverton, Christopher; Bogdanović, Borislav; Schüth, Ferdi

    2009-11-25

    A novel type of complex rare-earth aluminum hydride was prepared by mechanochemical preparation. The crystal structure of the REAlH(6) (with RE = La, Ce, Pr, Nd) compounds was calculated by DFT methods and confirmed by preliminary structure refinements. The trigonal crystal structure consists of isolated [AlH(6)](3-) octahedra bridged via [12] coordinated RE cations. The investigation of the rare-earth aluminum hydrides during thermolysis shows a decrease of thermal stability with increasing atomic number of the RE element. Rare-earth hydrides (REH(x)) are formed as primary dehydrogenation products; the final products are RE-aluminum alloys. The calculated decomposition enthalpies of the rare-earth aluminum hydrides are at the lower end for reversible hydrogenation under moderate conditions. Even though these materials may require somewhat higher pressures and/or lower temperatures for rehydrogenation, they are interesting examples of low-temperature metal hydrides for which reversibility might be reached.

  9. KINETICS OF GRAIN-GROWTH OF YTTRIUM ALUMINUM GARNET FIBERS PREPARED BY SOL-GEL METHOD

    Directory of Open Access Journals (Sweden)

    Tan H.

    2013-12-01

    Full Text Available The yttrium aluminum garnet (YAG long fibers were prepared by the sol-gel method using aluminum chloride, aluminum powder, yttrium oxide and acetic acid as raw materials. The grain growth law is given by Dn – D0n = Kt (D0 = initial grain size, D = average grain size at time t, n = grain growth exponent and K = reaction constant. The grain growth exponent and activation energy of YAG fibers are ≈ 3 and 200 kJ/mol, respectively. The grain-growth behaviors of YAG were influenced by experimental conditions such as raw materials, initial particle size, initial particle distribution, etc.

  10. The influence of surface topography on the forming friction of automotive aluminum sheet

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, Pamela Ann [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering

    1998-05-01

    Interest in utilizing aluminum alloys in automobiles has increased in recent years as a result of the desire to lower automobile weight and, consequently, increase fuel economy. While aluminum alloy use in cast parts has increased, outer body panel applications are still being investigated. The industry is interested in improving the formability of these sheet alloys by a combination of alloy design and processing. A different avenue of improving the formability of these alloys may be through patterning of the sheet surface. Surface patterns hold the lubricant during the forming process, with a resulting decrease in the sheet-die surface contact. While it has been speculated that an optimum surface pattern would consist of discrete cavities, detailed investigation into the reduction of forming friction by utilizing discrete patterns is lacking. A series of discrete patterns were investigated to determine the dependence of the forming friction of automotive aluminum alloys on pattern lubricant carrying capacity and on material strength. Automotive aluminum alloys used in outer body panel applications were rolled on experimental rolls that had been prepared with a variety of discrete patterns. All patterns for each alloy were characterized before and after testing both optically and, to determine pattern lubricant capacity, using three dimensional laser profilometry. A draw bead simulation (DBS) friction tester was designed and fabricated to determine the forming friction of the patterned sheets. Tensile testing and frictionless DBS testing were performed to ascertain the material properties of each sheet. The most striking result of this work was the inversely linear dependence of forming friction on the lubricant carrying capacity of the discrete patterns.

  11. Preparation of three-dimensional shaped aluminum alloy foam by two-step foaming

    Energy Technology Data Exchange (ETDEWEB)

    Shang, J.T. [Key laboratory of MEMS of Ministry of Education, Southeast University, Nanjing 210096 (China)], E-mail: Jshang@seu.edu.cn; Xuming, Chu; Deping, He [School of Materials Science and Engineering, Southeast University, Nanjing 210096 (China)

    2008-06-25

    A novel method, named two-step foaming, was investigated to prepare three-dimensional shaped aluminum alloy foam used in car industry, spaceflight, packaging and related areas. Calculations of thermal decomposition kinetics of titanium hydride showed that there is a considerable amount of hydrogen releasing when the titanium hydride is heated at a relatively high temperature after heated at a lower temperature. The hydrogen mass to sustain aluminum alloy foam, having a high porosity, was also estimated by calculations. Calculations indicated that as-received titanium hydride without any pre-treatment can be used as foaming agents in two-step foaming. The processes of two-step foaming, including preparing precursors and baking, were also studied by experiments. Results showed that, low titanium hydride dispersion temperature, long titanium hydride dispersion time and low precursors porosity are beneficial to prepare three-dimensional shaped aluminum alloy foams with uniform pores.

  12. Flexible Aluminum Nanobowls for Alternative Preparation of Individual or a Small Number of Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    SUN Yan; CHEN Xin; YUE Yang; ZHANG Rong-jun; DAI Ning

    2009-01-01

    The nanoscale aluminum bowls were derived from the porous alumina and were used as the flexible nanoscale reactors for the preparation of nanoparticles.Both single source precursor and preprepared nanoparticles were induced in the nanobowls by melting the precursor/polymer films spin-coated on aluminum nanobowis for the formation of nanostructural composites in the nanobowls.We have prepared a single nanoparticle or just a small number of metal(e.g.Pt) nanoparticles or semiconductor nanoparticles(e.g.CdSe or CdSe/ZnS core-shell nanostructures) in the nanobowls.

  13. Industrial preparation and performance testing of property-modified prebaked carbon anodes for aluminum electrolysis

    Institute of Scientific and Technical Information of China (English)

    肖劲; 李劼; 邹忠; 胡国荣; 赖延清; 刘业翔

    2003-01-01

    On the base of filtering composite additives in laboratory, the industrial property-modified prebaked car-bon anodes containing composite additives were prepared in factory. The performance tests show that this kind ofanodes not only have the same excellent physical performance as common (contrasting) ones used in aluminum elec-trolysis production at the present time, but also have better chemical and electrochemical performance than that ofthe common ones. Furthermore, the industrial preparation of the property-modified prebaked anode lays the founda-tion of electrolysis test. It can be forecasted that property-modified anodes will have good behavior in aluminum elec-trolysis production.

  14. Nicotine–magnesium aluminum silicate microparticle surface modified with chitosan for mucosal delivery

    Energy Technology Data Exchange (ETDEWEB)

    Kanjanakawinkul, Watchara [Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen 40002 (Thailand); Rades, Thomas [School of Pharmacy, University of Otago, Dunedin 9054 (New Zealand); Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen (Denmark); Puttipipatkhachorn, Satit [Department of Manufacturing Pharmacy, Faculty of Pharmacy, Mahidol University, Bangkok 10400 (Thailand); Pongjanyakul, Thaned, E-mail: thaned@kku.ac.th [Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen 40002 (Thailand)

    2013-04-01

    Magnesium aluminum silicate (MAS), a negatively charged clay, and nicotine (NCT), a basic drug, can interact electrostatically to form microparticles. Chitosan (CS) was used for the surface modification of the microparticles, and a lyophilization method was used to preserve the original particle morphology. The microparticles were characterized in terms of their physicochemical properties, NCT content, mucoadhesive properties, and release and permeation across porcine esophageal mucosa. The results showed that the microparticles formed via electrostatic interaction between MAS and protonated NCT had an irregular shape and that their NCT content increased with increasing NCT ratios in the microparticle preparation solution. High molecular weight CS (800 kDa) adsorbed to the microparticle surface and induced a positive surface charge. CS molecules intercalated into the MAS silicate layers and decreased the crystallinity of the microparticles, leading to an increase in the release rate and diffusion coefficient of NCT from the microparticles. Moreover, the microparticle surface modified with CS was found to have higher NCT permeation fluxes and mucoadhesive properties, which indicated the significant role of CS for NCT mucosal delivery. However, the enhancement of NCT permeation and of mucoadhesive properties depended on the molecular weight and concentration of CS. These findings suggest that NCT-MAS microparticle surface modified with CS represents a promising mucosal delivery system for NCT. Highlights: ► Nicotine–magnesium aluminum silicate microparticles were prepared using electrostatic interaction. ► Lyophilization was used for drying and maintaining an original morphology of the microparticles. ► Chitosan (CS) was used for surface modification of the microparticles at acidic pH. ► Surface modification using CS caused an increase in release and permeation of nicotine. ► Microparticle surface-modified with CS presented better mucoadhesive properties.

  15. New preparation of benzylic aluminum and zinc organometallics by direct insertion of aluminum powder.

    Science.gov (United States)

    Blümke, Tobias D; Groll, Klaus; Karaghiosoff, Konstantin; Knochel, Paul

    2011-12-16

    The reaction of commercial Al-powder (3 equiv) and InCl(3) (1-5 mol %) with benzylic chlorides provides various functionalized benzylic aluminum sesquichlorides under mild conditions (THF, 20 °C, 3-24 h) without homocoupling (organometallics reacted smoothly with various electrophiles (Pd-catalyzed cross-couplings, or Cu-mediated acylations, allylations, or 1,4-addition reactions). Electron-poor benzylic chlorides or substrates prone to Wurtz coupling can be converted to benzylic zinc compounds by the reaction of Al-powder in the presence of ZnCl(2).

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

    Science.gov (United States)

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

    2014-12-01

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

  17. Robust biomimetic-structural superhydrophobic surface on aluminum alloy.

    Science.gov (United States)

    Li, Lingjie; Huang, Tao; Lei, Jinglei; He, Jianxin; Qu, Linfeng; Huang, Peiling; Zhou, Wei; Li, Nianbing; Pan, Fusheng

    2015-01-28

    The following facile approach has been developed to prepare a biomimetic-structural superhydrophobic surface with high stabilities and strong resistances on 2024 Al alloy that are robust to harsh environments. First, a simple hydrothermal treatment in a La(NO3)3 aqueous solution was used to fabricate ginkgo-leaf like nanostructures, resulting in a superhydrophilic surface on 2024 Al. Then a low-surface-energy compound, dodecafluoroheptyl-propyl-trimethoxylsilane (Actyflon-G502), was used to modify the superhydrophilic 2024 Al, changing the surface character from superhydrophilicity to superhydrophobicity. The water contact angle (WCA) of such a superhydrophobic surface reaches up to 160°, demonstrating excellent superhydrophobicity. Moreover, the as-prepared superhydrophobic surface shows high stabilities in air-storage, chemical and thermal environments, and has strong resistances to UV irradiation, corrosion, and abrasion. The WCAs of such a surface almost remain unchanged (160°) after storage in air for 80 days, exposure in 250 °C atmosphere for 24 h, and being exposed under UV irradiation for 24 h, are more than 144° whether in acidic or alkali medium, and are more than 150° after 48 h corrosion and after abrasion under 0.98 kPa for 1000 mm length. The remarkable durability of the as-prepared superhydrophobic surface can be attributed to its stable structure and composition, which are due to the existence of lanthanum (hydr)oxides in surface layer. The robustness of the as-prepared superhydrophobic surface to harsh environments will open their much wider applications. The fabricating approach for such robust superhydrophobic surface can be easily extended to other metals and alloys.

  18. Surface modification of piezoelectric aluminum nitride with functionalizable organosilane adlayers

    Science.gov (United States)

    Chan, Edmund; Jackson, Nathan; Mathewson, Alan; Galvin, Paul; Alamin Dow, Ali B.; Kherani, Nazir P.; Blaszykowski, Christophe; Thompson, Michael

    2013-10-01

    The world of biosensors is expanding at a rapid pace with an ever-increasing demand for more sensitive miniaturized devices. Acoustic wave biosensors are not spared from this trend. In this domain, the search for enhanced sensitivity is increasingly oriented toward the rational design of new piezoelectric materials with superior properties to substitute for prevalent quartz. With respect to surface chemistry, construction of the biorecognition element, more often than not, requires the use of bifunctional molecules that can spontaneously assemble on the substrate and form organic surfaces readily biofunctionalizable in a subsequent, ideally single step. In this context, we present herein the surface modification of aluminum nitride (AlN) with alkyltrichlorosilane cross-linking molecules bearing a functionalizable benzenethiosulfonate moiety. This latter feature is next demonstrated through the straightforward, preactivation-free immobilization of thiolated biotin probes. To date, AlN has only received little attention in the field of piezoelectric biosensors despite its many attractive properties and the perspective to operate devices at ultra-high frequencies (GHz) with unprecedented sensitivity. To our knowledge, this work describes one of the first examples of direct surface derivatization of AlN with bifunctional trichlorosilane molecules. It also constitutes a first step toward the development of electrodeless GHz piezoelectric biosensing platforms based on AlN and trichlorosilane surface chemistry.

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

    Directory of Open Access Journals (Sweden)

    Susan Catieri Ramalho

    2013-08-01

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

  20. Preparation and Properties of Microarc Oxidation Self-Lubricating Composite Coatings on Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Zhenwei Li

    2017-04-01

    Full Text Available Microarc oxidation (MAO coatings were prepared on 2024-T4 aluminum alloy using pulsed bipolar power supply at different cathode current densities. The MAO ceramic coatings contained many crater-like micropores and a small number of microcracks. After the MAO coatings were formed, the coated samples were immersed into a water-based Polytetrafluoroethylene (PTFE dispersion. The micropores and microcracks on the surface of the MAO coatings were filled with PTFE dispersion for preparing MAO self-lubricating composite coatings. The microstructure and properties of MAO coatings and the wear resistance of microarc oxidation self-lubricating composite coatings were analyzed by SEM, laser confocal microscope, X-ray diffractometry (XRD, Vickers hardness test, scratch test and ball-on-disc abrasive tests, respectively. The results revealed that the wear rates of the MAO coatings decreased significantly with an increase in cathode current density. Compared to the MAO coatings, the microarc oxidation self-lubricating composite coatings exhibited a lower friction coefficient and lower wear rates.

  1. Direct spray pyrolysis of aluminum chloride solution for alumina preparation

    Institute of Scientific and Technical Information of China (English)

    吕国志; 张廷安; 王龙; 马思达; 豆志河; 刘燕

    2014-01-01

    The effects of pyrolysis mode and pyrolysis parameters on Cl content in alumina were investigated, and the alumina products were characterized by XRD, SEM and ASAP. The experimental results indicate that the spray pyrolysis efficiency is higher than that of static pyrolysis process, and the reaction and evaporation process lead to a multi-plot state of the alumina products by spray pyrolysis. Aluminum phase starts to transform intoγ-Al2O3 at spray pyrolysis temperature of 600 °C, which is about 200 °C lower than that of static pyrolysis process. The primary particle size of γ-Al2O3 product is 27.62 nm, and Cl content in alumina products is 0.38%at 800 °C for 20 min.

  2. Research on Semisolid Microstructural Evolution of 2024 Aluminum Alloy Prepared by Powder Thixoforming

    Directory of Open Access Journals (Sweden)

    Pubo Li

    2015-04-01

    Full Text Available A novel method, powder thixoforming, for net-shape forming of the particle-reinforced Aluminum matrix composites in semi-solid state has been proposed based on powder metallurgy combining with thixoforming technology. The microstructural evolution and phase transformations have been investigated during partial remelting of the 2024 bulk alloy, prepared by cold pressing of atomized alloy powders to clarify the mechanisms of how the consolidated powders evolve into small and spheroidal primary particles available for thixoforming. The effect of heating temperature on the resulting semisolid microstructure has also been discussed. The results indicate that the microstructural evolution includes three stages—the initial rapid coarsening of the fine grains within the powders, the formation of continuous liquid layer on the primary particle surface (the original powder, and the final coarsening—that result from the phase transformations of θ→α, α→L, and α→L and L→α, respectively. The coarsening rate of the primary particles is low, and one original powder always evolves into one spheroidal particle with a continuous liquid layer surface. Properly raising the heating temperature is beneficial for obtaining an ideal semisolid microstructure.

  3. Laser Surface Preparation for Adhesive Bonding of Aerospace Structural Composites

    Science.gov (United States)

    Belcher, M. A.; Wohl, C. J.; Hopkins, J. W.; Connell, J. W.

    2010-01-01

    Adhesive bonds are critical to the integrity of built-up structures. Disbonds can often be detected but the strength of adhesion between surfaces in contact is not obtainable without destructive testing. Typically the number one problem in a bonded structure is surface contamination, and by extension, surface preparation. Standard surface preparation techniques, including grit blasting, manual abrasion, and peel ply, are not ideal because of variations in their application. Etching of carbon fiber reinforced plastic (CFRP) panels using a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser appears to be a highly precise and promising way to both clean a composite surface prior to bonding and provide a bond-promoting patterned surface akin to peel ply without the inherent drawbacks from the same (i.e., debris and curvature). CFRP surfaces prepared using laser patterns conducive to adhesive bonding were compared to typical pre-bonding surface treatments through optical microscopy, contact angle goniometry, and post-bonding mechanical testing.

  4. Microstructural Evolution of Semisolid 6063 Aluminum Alloy Prepared by Recrystallization and Partial Melting Process

    Science.gov (United States)

    Wang, Yongfei; Zhao, Shengdun; Zhang, Chenyang

    2017-08-01

    Radial forging (RF) was proposed as a novel deformation method to prepare semisolid 6063 aluminum alloy in the recrystallization and partial melting (RAP) process. The effects of area reduction rate, isothermal holding temperature and time on the microstructural evolution of RF-deformed 6063 aluminum alloy were investigated. Results showed that RF can be successfully introduced in RAP process to prepare large semisolid 6063 aluminum alloy bar. With the increase of the area reduction rate, the average grain size firstly decreased and then no significant change occurred. Meanwhile, the spheroidization degree of solid grains firstly increased rapidly, and then increased slowly. The effects of isothermal holding temperature and time are similar, with the increase of the isothermal holding temperature or time, the average grain size initially decreased but then increased; and the spheroidization degree of solid grains gradually increased. High-quality semisolid 6063 aluminum alloy can be prepared with 70% area reduction rate and subsequent semisolid isothermal treatment (SSIT) at 630 °C for 10 min. The coarsening rate constant was 5185.2 µm3/s at 630 °C. Additionally, a strong deformation texture was created in the RF-deformed alloy with 70% area reduction rate, which was transformed to a weakened texture following the SSIT process.

  5. Characteristics and properties of metal aluminum thin films prepared by electron cyclotron resonance plasma-assisted atomic layer deposition technology

    Institute of Scientific and Technical Information of China (English)

    Xiong Yu-Qing; Li Xing-Cun; Chen Qiang; Lei Wen-Wen; Zhao Qiao; Sang Li-Jun; Liu Zhong-Wei; Wang Zheng-Duo; Yang Li-Zhen

    2012-01-01

    Metal aluminum (Al) thin films are prepared by 2450 MHz electron cyclotron resonance plasma-assisted atomic layer deposition on glass and p-Si substrates using trimethylaluminum as the precursor and hydrogen as the reductive gas.We focus our attention on the plasma source for the thin-film preparation and annealing of the as-deposited films relative to the surface square resistivity.The square resistivity of as-deposited Al films is greatly reduced after annealing and almost reaches the value of bulk metal.Through chemical and structural analysis,we conclude that the square resistivity is determined by neither the contaminant concentration nor the surface morphology,but by both the crystallinity and crystal size in this process.

  6. Preparation of Ni-CNT composite coatings on aluminum substrate and its friction and wear behavior

    Institute of Scientific and Technical Information of China (English)

    涂江平; 朱丽萍; 陈卫祥; 赵新兵; 刘芙; 张孝彬

    2004-01-01

    Nickel-carbon nanotube(CNT) composite coatings with a Zn-Ni interlayer were prepared by electrodeposition technique on aluminum substrate. The effects of CNT concentration in plating bath on the volume fraction of CNTs in the deposits and the coating growth rate were investigated. The friction and wear behavior of the Ni-CNT composite coatings were examined using a pin-on-disk wear tester under dry sliding conditions at a sliding speed of 0. 062 3 m/s and load range from 12 N to 150 N. Because of the reinforcement of CNTs in the composite coatings, at lower applied loads, the wear resistance was improved with increasing volume fraction of CNTs. Since cracking and peeling occur on the worn surface, the wear rates of composite coatings with high volume fraction of CNTs increase rapidly at higher applied loads. The friction coefficient of the composite coatings decreases with the increasing volume fraction of CNTs due to the reinforcement and self-lubrication of CNTs.

  7. Preparation of Metallic Aluminum Compound Particles by Submerged Arc Discharge Method in Aqueous Media

    Science.gov (United States)

    Liao, Chih-Yu; Tseng, Kuo-Hsiung; Lin, Hong-Shiou

    2013-02-01

    Fine metal particles are produced by chemical methods, which add surfactants to control particle size and concentration. This study used the submerged arc discharge method (SADM) to prepare metal fluid containing nanoparticles and submicron particles in pure dielectric fluid (deionized water or alcohol). The process is fast and simple, and it does not require the addition of chemical agents. The SADM uses electrical discharge machining (EDM) equipment, and the key parameters of the production process include discharge voltage, current, and pulse discharge on-off duration. This study added a capacitive component between the electrodes and the electrode Z-axis regulation in the control parameters to render the aluminum fluid process smooth, which is the main difference of this article from the literature. The experimental results showed that SADM can produce aluminum particles from nanometer to submicron grade, and it can obtain different compounds from different dielectric fluids. The dielectric fluids used in this study were deionized water and ethanol, and aluminum hydroxide Al(OH)3 particles with suspending power and precipitated aluminum particles were obtained, respectively. The preparations of metal colloid and particles by the SADM process have the characteristics of low cost, high efficiency, high speed, and mass production. Thus, the process has high research value and developmental opportunities.

  8. Preparation technology and anti-corrosion performances of black ceramic coatings formed by micro-arc oxidation on aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    CHEN Ling; HAN Jing; YU Shengxue

    2006-01-01

    In order to prepare ornamental and anti-corrosive coating on aluminum alloys, preparation technology of black micro-arc ceramic coatings on Al alloys in silicate based electrolyte was studied.The influence of content of Na2WO4 and combination additive in solution on the performance of black ceramic coatings was studied; the anticorrosion performances of black ceramic coatings were evaluated through whole-immersion test and electrochemical method in 3.5% NaCl solution at different pH value; SEM and XRD were used to analyze the surface morphology and phase constitutes of the black ceramic coatings.Experimental results indicated that, without combination additives, with the increasing of Na2WO4 content in the electrolyte, ceramic coating became darker and thicker, but the color was not black; after adding combination additive, the coating turned to be black; the black ceramic coating was multi-hole form in surface.There was a small quantity of tungsten existing in the black ceramic coating beside α-Al2O3 phase and β-Al2O3 phase.And aluminum alloy with black ceramic coating exhibited excellent anti-corrosion property in acid, basic and neutral 3.5% NaCl solution.

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

    Science.gov (United States)

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

    2016-12-01

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

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

    Directory of Open Access Journals (Sweden)

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

    2003-01-01

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

  11. Preparation of Scandium-Bearing Master Alloys by Aluminum-Magnesium Thermoreduction

    Institute of Scientific and Technical Information of China (English)

    姜锋; 白兰; 尹志民

    2002-01-01

    The new preparation method of scandium-bearing master alloys, in which scandium oxide was fluorinated by reaction with NH4HF2 and then reduced by aluminum-magnesium in fused salt containing alkali and alkaline fluoride under atmosphere, was studied. The effect of sorts of metallic reductive and technique conditions such as reducing temperature and time on the recovery of Sc was discussed. When the liquid aluminum-magnesium was used as the reductive agent, the all-recovery exceeds 80% and the concentration of Sc in master alloy prepared exceeds 1.9%. The best reducing reaction temperature and time are 1100 K and 40 min respectively. The newly produced Sc from reduction combines with Al to produce the stable compound Al3Sc, so the reduction progress is sustained and the recovery of Sc is increased.

  12. A perspective of microplasma oxidation (MPO) and vapor deposition coatings in surface engineering of aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    AWAD Samir Hamid; QIAN Han-cheng

    2004-01-01

    Over the past years, great achievements have been made in the development of coating technologies for surface improvement of aluminum alloys. Despite these achievements, the role in the market strongly depends on the ability of surface coating technology under technical and economic considerations to meet the increased demands for heavy tribological applications of aluminum alloys. Microplasma oxidation (MPO) technology has recently been studied as a novel and effective means to provide thick and hard ceramic coating with improved properties such as excellent load-bearing and wear resistance properties on aluminum alloys. The present work covers the evaluation of the performances of current single and duplex coatings combining MPO, physical vapor deposition (PVD), and plasma assisted chemical vapor deposition (PACVD) coatings on aluminum alloys. It suggests that the MPO coating is a promising candidate for design engineers to apply aluminum alloys to heavy load-bearing applications. The prospective future for the research on MPO coatings is introduced as well.

  13. Research on Semisolid Microstructural Evolution of 2024 Aluminum Alloy Prepared by Powder Thixoforming

    OpenAIRE

    Pubo Li; Tijun Chen; Suqing Zhang; Renguo Guan

    2015-01-01

    A novel method, powder thixoforming, for net-shape forming of the particle-reinforced Aluminum matrix composites in semi-solid state has been proposed based on powder metallurgy combining with thixoforming technology. The microstructural evolution and phase transformations have been investigated during partial remelting of the 2024 bulk alloy, prepared by cold pressing of atomized alloy powders to clarify the mechanisms of how the consolidated powders evolve into small and spheroidal primary...

  14. Preparation of Al-Sr Master Alloy in Aluminum Electrolysis Cell

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Al-Sr master alloy was prepared by using liquid aluminum cathode and a mixture of Na3AlF6- SrCO3 as the basic molten salt electrolyte in a laboratory electrolysis cell.The effects of electrolyte composition,electrolysis temperature,cathodic current density and the electrolytic duration on Sr content of Al-Sr alloy were studied.Through laboratory experiments,the parameters for smooth electrolytic reaction were proposed.

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

    Science.gov (United States)

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

    2014-09-01

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

  16. Surface-enhanced Raman scattering on aluminum using near infrared and visible excitation

    DEFF Research Database (Denmark)

    Mogensen, Klaus Bo; Gühlke, Marina; Kneipp, Janina;

    2014-01-01

    We observed strong surface-enhanced Raman scattering on discontinuous nanostructured aluminum films using 785 nm excitation even though dielectric constants of this metal suggest plasmon supported spectroscopy in the ultraviolet range. The excitation of SERS correlates with plasmon resonances...

  17. Development and mean life of aluminum first-surface mirrors for solar energy applications

    Energy Technology Data Exchange (ETDEWEB)

    Almanza, Rafael; Hernandez, Perla; Martinez, Ivan [Instituto de Ingenieria, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Mexico DF, 04510 (Mexico); Mazari, Marcos [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Mexico DF, 04510 (Mexico)

    2009-09-15

    Aluminum solar mirrors are an alternative for solar concentrators. This paper presents the first aluminum-surface solar mirrors, which, after 12 years of exposure to the aggressive weather conditions of Mexico City, have a reflectance decrease of only 3% (from 0.85 to 0.82), with only small scratches on the SiO{sub 2} layer. Furthermore, two alternatives are presented for solar aluminum mirrors: mirrors with integrated first and second surfaces and first-surface compound mirrors. Each mirror and its fabrication are described, along with their weather tests. The aluminum first-surface solar mirror lasts for at least 12 years, and is a good alternative material for parabolic troughs, heliostats, CPC, Fresnel technology and dish concentrators. (author)

  18. Effect of Heat Treatment on Mechanical Properties and Phase Composition of Magnesium-Aluminum Composite Prepared by Explosive Welding

    Science.gov (United States)

    Arisova, V. N.; Trykov, Yu. P.; Slautin, O. V.; Ponomareva, I. A.; Kondakov, A. E.

    2015-09-01

    Results are given for a study of the effect of heat treatment regimes on the nature of change in micromechanical properties and phase composition of magnesium-aluminum composite material AD1-MA2-1 prepared by explosive welding.

  19. Corrosion control of aluminum surfaces by polypyrrole films: influence of electrolyte

    Directory of Open Access Journals (Sweden)

    Andréa Santos Liu

    2007-06-01

    Full Text Available Polypyrrole (PPy films were galvanostatically deposited on 99.9 wt. (% aluminum electrodes from aqueous solutions containing each carboxylic acid: tartaric, oxalic or citric. Scanning Electron Microscopy (SEM was used to analyze the morphology of the aluminum surfaces coated with the polymeric films. It was observed that the films deposited from tartaric acid medium presented higher homogeneity than those deposited from oxalic and citric acid. Furthermore, the corrosion protection of aluminum surfaces by PPy films was also investigated by potentiodynamic polarization experiments.

  20. Surface passivation of aluminum alloy 6061 with gaseous trichlorosilane: A surface investigation

    Energy Technology Data Exchange (ETDEWEB)

    Ngongang, Rickielle, E-mail: rickielle.ngongang@airliquide.com [Centre de Recherche Claude Delorme, Air Liquide, 1 Chemin de la Porte des Loges Les-Loges en Josas, 78350 Jouy-en-Josas (France); Laboratoire de Réactivité de Surface, UMR CNRS 7197, UPMC (Université Pierre et Marie Curie-Paris 6), site d’Ivry, 3 rue Galilée, 94200 Ivry-sur-Seine (France); Marceau, Eric; Carrier, Xavier; Pradier, Claire-Marie; Methivier, Christophe [Laboratoire de Réactivité de Surface, UMR CNRS 7197, UPMC (Université Pierre et Marie Curie-Paris 6), site d’Ivry, 3 rue Galilée, 94200 Ivry-sur-Seine (France); Blanc, Jean-Luc; Carre, Martine [Centre de Recherche Claude Delorme, Air Liquide, 1 Chemin de la Porte des Loges Les-Loges en Josas, 78350 Jouy-en-Josas (France)

    2014-02-15

    A molecular-scale investigation of the interaction at room temperature between gaseous trichlorosilane (HSiCl{sub 3}), used as a passivating agent, and surfaces of aluminum alloy AA6061 in a polished or hydroxylated state is conducted. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) provide information on the topography and morphology of AA6061 before and after hydroxylation and surface passivation, while surface chemistry has been investigated by Polarization Modulation Infrared Reflection-Absorption Spectroscopy (PM-IRRAS) and X-ray photoelectron spectroscopy (XPS). Oxidation and hydroxylation of the polished alloy surface in boiling water strongly modifies the roughness of the surface, with formation of platelets and needles of oxyhydroxide AlOOH. PM-IRRAS and XPS reveal that, upon adsorption, HSiCl{sub 3} dissociates and mainly forms HSiOH{sub n}(OAl){sub 3−n}, HSi(OSi){sub n}(OAl){sub 3−n} and condensed HSiO{sub x} species, by reaction with -OH groups from the AlOOH surface phase. The amount of deposited Si-containing species is larger on the rough surface of the hydroxylated alloy and this deposit is accompanied by a decrease of the amount of free -OH groups evidenced by PM-IRRAS. These results can find applications in the field of functionalization of aluminum alloys. It is suggested that a homogeneous oxidation of the alloy surface prior to exposure to gaseous HSiCl{sub 3} may enhance the adsorption of the passivating agent.

  1. Topographical Parameter Characteristics of Dry Sliding Surfaces of Particle-Reinforced Aluminum Composites

    Institute of Scientific and Technical Information of China (English)

    陈跃; 上官宝; 张永振; 孙乐民; 铁喜顺; 夏跃虹

    2004-01-01

    Generally, friction and wear occur on the surface of the materials.It is necessary to investigate the dry sliding friction and wear behavior of surface.In this paper, 3-D topographical parameters were used to investigate the topographical characteristics of dry sliding surfaces for particle-reinforced aluminum composites on semi-metallic friction material.The experimental results indicate that the surface topography of the particle-reinforced aluminum composites can be divided into two types, the flaking-off pit type and the groove type.The composites whose surface topography is the flaking-off pit type possess superior heat conductivity and bearing area, lower wear rate, and higher friction coefficient than the groove type.Consequently, the flaking-off pit type surface topography is much better than the groove type for particle-reinforced aluminum composites on semi-metallic friction materials in dry sliding.

  2. Graphene-reinforced aluminum matrix composites prepared by spark plasma sintering

    Institute of Scientific and Technical Information of China (English)

    Wen-ming Tian; Song-mei Li; Bo Wang; Xin Chen; Jian-hua Liu; Mei Yu

    2016-01-01

    Graphene-reinforced 7055 aluminum alloy composites with different contents of graphene were prepared by spark plasma sinter-ing (SPS). The structure and mechanical properties of the composites were investigated. Testing results show that the hardness, compressive strength, and yield strength of the composites are improved with the addition of 1wt% graphene. A clean, strong interface is formed between the metal matrix and graphene via metallurgical bonding on atomic scale. Harmful aluminum carbide (Al4C3) is not formed during SPS processing. Further addition of graphene (above 1wt%) results in the deterioration in mechanical properties of the composites. The agglomeration of graphene plates is exacerbated with increasing graphene content, which is the main reason for this deterioration.

  3. Preparation of nano-sized hydrophilic aluminum fins coating materials for air conditioner

    Institute of Scientific and Technical Information of China (English)

    陈志明; 韩峰; 邵利

    2002-01-01

    Semicontinuous seeded emulsion copolymerization of acrylic acid, acrylamide and divinylbenzene was carried out at 80℃ with ammonium persulphate as the initiator and the polyether with comb configuration as the emulsifier to prepare approximately mono-dispersed nano-sized polymer particles with average diameter 90nm. The particles were used to combine with special polyether and de-ionized water was added to obtain nano-sized hydrophilic aluminum fins coating materials with solid content of 10%. The aluminum fins were coated with the materials to get the film showing self-assembly properties in some degree. The obtained hydrophilic fins have contact angles <5° with de-ionized water, minimum value 0°, after 4 cycles of wet and dry, contact angles <10° with de-ionized water.

  4. Preparation of Ti3SiC2 with Aluminum by Means of Spark Plasma Sintering

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Polycrystalline bulk Ti3SiC2 material with a high purity and density was fabricated by spark plasma sintering from the elemental powder mixture with starting composition of Ti3Si1-xAlxC2,where x=0.05-0.2.X-ray diffraction patterns and scanning electron microscopy photographs of the fully dense samples show that a proper addition of aluminum promotes the formation,and accelerates the crystal growth rate of Ti3SiC2,consequently results in a high purity of the prepared samples.The synthesized Ti3SiC2 is in plane-shape with a size of about 10-25μm in the elongated dimension.Solid solution of aluminum decreases the thermal stability of Ti3SiC2,and lowers the temperature of Ti3SiC2 decomposeing to be 1300 ℃.

  5. Modification and characterization of aluminum nitride surfaces for an acoustic wave biosensor

    Science.gov (United States)

    Rosenberger, Leland W.

    Aluminum nitride (AlN) is a piezoelectric material that is being developed for use in a surface acoustic wave sensor for the detection of bacteria in fluid media. An AlN film is deposited on a sapphire or silicon substrate. After conductor deposition, an electronic signal is applied across the device and the signal is modified by changes in the mass immobilized on the sensor surface. Bacteria are immobilized on the surface by antibodies specific to the bacterial species. The problem addressed in this dissertation is how to form a bridge between the inorganic surface and the antibodies. The approach used is to form a new chemical layer on the AlN by using silanes. Functional groups on the silane surface can then be used as anchor points for the antibodies. This approach was carried out in three steps: (1) characterize the AlN surface, (2) explore four surface treatment methods that prepare the AlN surface for silanization and (3) silanize the resulting surface. AlN films were deposited by a Plasma Source Molecular Beam Epitaxy method. The films were characterized by RHEED, X-ray diffraction, air/water contact angle, atomic force microscopy (AFM), ellipsometry and X-ray photoelectron spectroscopy (XPS). The four surface treatment methods explored were: immersion in boiling water, exposure to laser light, immersion in piranha solution and treatment with plasma. Samples were characterized by contact angle, AFM and XPS. Plasma treatment was preferred because it prepared the surface most effectively, without any loss of sub-surface AlN. Samples of AlN were silanized with two types of silane, along with silicon controls. Samples were characterized by contact angle, AFM and XPS. The effectiveness of silanes on AlN was equal to or somewhat less than that observed on silicon. AlN samples were also co-deposited with two different silanes and then the end group on one of the silanes was chemically modified. This demonstrated that the density of functional groups on the

  6. Novel Nano Boehmite prepared by Solvothermal reaction of aluminum hydroxide gel in Monoethanolamine

    Science.gov (United States)

    Ohta, Yasuhiro; Hayakawa, Tomokatsu; Inomata, Tomohiko; Ozawa, Tomohiro; Masuda, Hideki

    2017-07-01

    Solvothermal reaction of aluminum hydroxide gel (AHG) in monoethanolamine (MEA) was studied at several temperatures (100, 120, 150, and 200 °C) in several reaction times (2, 3, 4, 5, 6, and 13 h). The reaction product prepared at a low temperature of 120 °C in the reaction time more than 6 h gave a blue photoluminescence nanoboehmite intercalated with monoethanolamine derivatives (BM-MEA) in the colloidal solution, which showed a photoluminescence emission centered at 420 nm with an excitation of 360 nm. The powdery samples recovered from the reaction products were characterized by using elemental analysis, XRD analysis, IR spectroscopy, thermogravimetric (TG)-DTA, 13C and 27Al CP/MAS NMR spectroscopies, N2 gas adsorption/desorption isotherm, SEM and TEM images, and photoluminescence spectroscopy. The X-ray diffraction revealed that the basal space in BM-MEA was expanded from 0.61 to 1.2 nm by intercalation of MEA derivatives to boehmite, and the IR and 13C CP/MAS NMR spectra determined that the intercalated MEA derivatives are protonated- and carbamate-substituted MEAs, which are formed in the layers through a covalent bond with Al-OH groups on boehmite surface. The empirical formula of BM-MEA was estimated to be AlO(OH)0.82(OCH2CH2NH3 +)0.05(OCH2CH2NHCOO-)0.13 on the basis of the elemental TG-DTA and IR spectral analyses. We discuss the reaction mechanism of a unique blue photoluminescence BM-MEA formed by proceeding in CO2-H2O-alkanolamine system.

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

    Science.gov (United States)

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

    2013-10-01

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

  8. 40 CFR 63.5752 - How do I calculate the organic HAP content of aluminum recreational boat surface coatings?

    Science.gov (United States)

    2010-07-01

    ... the organic HAP content of aluminum recreational boat surface coatings? (a) Use equation 1 of this... 12 months. ER22AU01.017 Where: HAPSC = weighted-average organic HAP content for all aluminum coating materials, kilograms of organic HAP per liter of coating solids. m = number of different aluminum...

  9. Development of nanostructured coatings for protecting the surface of aluminum alloys against corrosion and ice accretion

    Science.gov (United States)

    Farhadi, Shahram

    Ice and wet snow accretion on outdoor structures is a severe challenge for cold climate countries. A variety of de-icing and anti-icing techniques have been developed so far to counter this problem. Passive approaches such as anti-icing or icephobic coatings that inhibit or retard ice accumulation on the surfaces are gaining in popularity. Metal corrosion should also be taken into account as metallic substrates are subject to corrosion problems when placed in humid or aggressive environments. Development of any ice-releasing coatings on aluminum structures, as they must be durable enough, is therefore closely related to anti-corrosive protection of that metal. Accordingly, series of experiments have been carried out to combine reduced ice adhesion and improved corrosion resistance on flat AA2024 substrates via thin films of single and double layer alkyl-terminated SAMs coatings. More precisely, alkyl-terminated aluminum substrates were prepared by depositing layer(s) of 18C-SAMs on BTSE-grafted AA2024 or mirror-polished AA2024 surfaces. This alloy is among the most widely used aluminum alloys in transportation systems (including aircraft), the military, etc. The stability of the coatings in an aggressive environment, their overall ice-repellent performance as well as their corrosion resistance was systematically studied. The stability of one-layer and two-layer coatings in different media was tested by means of CA measurements, demonstrating gradual loss of the hydrophobic property after ~1100-h-long immersion in water, associated by decrease in water CA. Surface corrosion was observed in all cases, except that the double-layer coating system provided improved anti-corrosive protection. All single layer coatings showed initial shear stress of ice detachment values of ~1.68 to 2 times lower than as-received aluminum surfaces and about ~1.22 to 1.5 times lower than those observed on mirror-polished surfaces. These values gradually increased after as many as 5 to 9

  10. Anomalous hexagonal superstructure of aluminum oxide layer grown on NiAl(110) surface

    Science.gov (United States)

    Krukowski, Pawel; Chaunchaiyakul, Songpol; Minagawa, Yuto; Yajima, Nami; Akai-Kasaya, Megumi; Saito, Akira; Kuwahara, Yuji

    2016-11-01

    A modified method for the fabrication of a highly crystallized layer of aluminum oxide on a NiAl(110) surface is reported. The fabrication method involves the multistep selective oxidation of aluminum atoms on a NiAl(110) surface resulting from successive oxygen deposition and annealing. The surface morphology and local electronic structure of the novel aluminum oxide layer were investigated by high-resolution imaging using scanning tunneling microscopy (STM) and current imaging tunneling spectroscopy. In contrast to the standard fabrication method of aluminum oxide on a NiAl(110) surface, the proposed method produces an atomically flat surface exhibiting a hexagonal superstructure. The superstructure exhibits a slightly distorted hexagonal array of close-packed bright protrusions with a periodicity of 4.5 ± 0.2 nm. Atomically resolved STM imaging of the aluminum oxide layer reveals a hexagonal arrangement of dark contrast spots with a periodicity of 0.27 ± 0.02 nm. On the basis of the atomic structure of the fabricated layer, the formation of α-Al2O3(0001) on the NiAl(110) surface is suggested.

  11. Semisolid slurry of 7A04 aluminum alloy prepared by electromagnetic stirring and Sc, Zr additions

    Directory of Open Access Journals (Sweden)

    Jun-wen Zhao

    2017-05-01

    Full Text Available Slurry preparation is one of the most critical steps for semisolid casting, and its primary goal is to prepare slurry with uniformly distributed fine globules. In this work, electromagnetic stirring (EMS and the addition of Sc and Zr elements were used to prepare semisolid slurry of 7A04 aluminum alloy in a large diameter slurry maker. The effects of different treatments on the microstructure, composition and their radial homogeneity were investigated. The results show that, compared to the slurry without any treatment, large volume slurry with finer and more uniform microstructure can be obtained when treated by EMS, Sc, or Zr additions individually. EMS is more competent in the microstructural and chemical homogenization of the slurry while Sc and Zr additions are more excellent in its microstructural refinement. The combined treatment of EMS, Sc and Zr produces premium 7A04 aluminum alloy slurry with uniformly distributed fine α-Al globules and composition. The interaction mechanism between EMS and Sc and Zr additions was also discussed.

  12. Preparation and analysis of anodic aluminum oxide films with continuously tunable interpore distances

    Science.gov (United States)

    Qin, Xiufang; Zhang, Jinqiong; Meng, Xiaojuan; Deng, Chenhua; Zhang, Lifang; Ding, Guqiao; Zeng, Hao; Xu, Xiaohong

    2015-02-01

    Nanoporous anodic aluminum oxides are often used as templates for preparation of nanostructures such as nanodot, nanowire and nanotube arrays. The interpore distance of anodic aluminum oxide is the most important parameter in controlling the periodicity of these nanostructures. Herein we demonstrate a simple and yet powerful method to fabricate ordered anodic aluminum oxides with continuously tunable interpore distances. By using mixed solution of citric and oxalic acids with different molar ratio, the range of anodizing voltages within which self-ordered films can be formed were extended to between 40 and 300 V, resulting in the interpore distances change from 100 to 750 nm. Our work realized very broad range of interpore distances in a continuously tunable fashion and the experiment processes are easily controllable and reproducible. The dependence of the interpore distances on acid ratios in mixed solutions was discussed through analysis of anodizing current and it was found that the effective dissociation constant of the mixed acids is of great importance. The interpore distances achieved are comparable to wavelengths ranging from UV to near IR, and may have potential applications in optical meta-materials for photovoltaics and optical sensing.

  13. Preparation and Characterization of Amorphous Layer on Aluminum Alloy Formed by Plasma Electrolytic Deposition (PED)

    Institute of Scientific and Technical Information of China (English)

    GUAN Yong-jun; XIA Yuan

    2004-01-01

    In this investigation, protective layers were formed on aluminum substrate by Plasma Electrolytic Deposition (PED) using sodium silicate solution. The relation between the thickness of the layer and process time were studied. XRD,SEM, EDS were used to study the layer's structure, composition and micrograph. The results show that the deposited layers are amorphous and contain mainly oxygen, silicon, and aluminum. The possible formation mechanism of amorphous [Al-Si-O] layer was proposed: During discharge periods, Al2O3 phase of the passive film and SiO32-near the substrate surface are sintered into xSiO2(1-x)Al2O3 and then transformed into amorphous [Al-Si-O] phase.

  14. Fabrication of super-hydrophobic surfaces on aluminum alloy substrates by RF-sputtered polytetrafluoroethylene coatings

    Directory of Open Access Journals (Sweden)

    Yang Wang

    2014-03-01

    Full Text Available In this work, we present a method of fabricating super-hydrophobic surface on aluminum alloy substrate. The etching of aluminum surfaces has been performed using Beck's dislocation etchant for different time to create micrometer-sized irregular steps. An optimised etching time of 50 s is found to be essential before polytetrafluoroethylene (PTFE coating, to obtain a highest water contact angle of 165±2° with a lowest contact angle hysteresis as low as 5±2°. The presence of patterned microstructure as revealed by scanning electron microscopy (SEM together with the low surface energy ultrathin RF-sputtered PTFE films renders the aluminum alloy surfaces highly super-hydrophobic.

  15. Effect of TiH2 on preparation of closed-cell aluminum foam and its compressive behavior

    Institute of Scientific and Technical Information of China (English)

    YANG Guo-jun; YU Hai-jun; YAO Guang-chun

    2006-01-01

    The vesicant problem during the process of preparing closed-cell aluminum foam by molten body transitional foaming process was discussed and the effect of granularity and addition of TiH2 on porosity of closed-cell aluminum foam was investigated.The static compressive behavior of closed-cell aluminum foam and the influence of porosity on static compressive property of closed-cell aluminum foam were researched as well. The results show that with increasing granularity of TiH2, the porosity of closed-cell aluminum foam firstly increases and then decreases gradually, the granularity should be controlled in the range of 38-74 μm which can result in higher porosity. The porosity of closed-cell aluminum foam increases with the increasing addition of TiH2,and the addition of TiH2 should be controlled from 1.5% to 2.5% which can result in homogeneous cell and moderate strength of closed-cell aluminum foam. The compressive process of closed-cell aluminum foam obviously displays linear elastic phase, plastic collapse phase, and densification phase, and the compressive strength grows with decreasing porosity.

  16. Dental enamel: qualitative evaluation of the surface after application of aluminum oxide (microetching using the scanning electron microscope

    Directory of Open Access Journals (Sweden)

    SILVA Paulo César Gomes

    2000-01-01

    Full Text Available Dentistry nowadays can count on a wide range of resources to treat patients. With the development of adhesive materials and several newly introduced restorative techniques, the dental structure can be subjected to different sorts of surface treatment. The use of aluminum oxide flow at high speed to remove dental structure was described by Black in 1945, however, the literature regarding the use of aluminum oxide jet is still scarce, as far as the alterations occurring in the dental structure are concerned. At the present, with the development of new abrasive air equipment, microabrasion has been added to several adhesive restorative techniques, in the preparation of the dental surface and of inner surfaces of indirect restorations, which will receive the application of adhesive materials. The aim of this study was to assess the alterations produced by abrasive air applied on the dental enamel by means of electronic microscopy, taking into consideration micromorphological surface alterations. The importance of this study is based on the fact that alternative surface treatments both chemical and mechanical could be introduced in surface priming, including dental enamel priming.

  17. Preparation of neodymium-doped yttrium aluminum garnet powders and fibers

    Institute of Scientific and Technical Information of China (English)

    R.López; J.Zárate; E.A.Aguilar; J.Mu(n)oz-Salda(n)a

    2008-01-01

    Using nitrate precursors, a novel spray-drying assisted citrate gel process for the preparation of neodymium-doped yttrium alumi-num garnet (YAG) phase was developed. Synthesis of single-phase polycrystalline YAG was achieved at temperatures as low as 800 ℃ us-ing the spray-drying methodology whilst conventional approaches currently available require 1000 ℃. Initially, a solution was prepared by mixing aluminum and yttrium nitrates, citric acid, etilenglycol and neodymium oxide. This solution was dried by pulverization (spray dryer) to obtain aggregated precursor powders of the compound. These aggregates were calcined at 800, 850 and 900 ℃ to determine the phase evolution from amorphous to crystalline by X-ray diffraction (XRD). The morphology of aggregates was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Moreover, through XRD it was determined that the crystallization of YAG phase started at about 800 ℃ without any intermediate phases. The powders were composed of spherical aggregates with an average diame-ter of 1 μm. From these powders, ceramic fibers with additions of 2at.% and 5at.% Nd, were extracted from the melt with diameters ranging from 30 μm to 50 μm.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-08-30

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

  19. Preparation of semi-solid slurry containing fine and globular particles for wrought aluminum alloy 2024

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The semi-solid slurry of wrought aluminum alloy 2024 was prepared by a well developed rheocasting process, low superheat pouring with shearing field(LSPSF). The appreciate combination of pouring temperature and rotation speed of barrel, can give rise to a transition of the growth morphology of primary α(Al) from coarse-dendritic to coarse-particle-like and further to fine-globular. The combined effects of both localized rapid cooling and vigorous mixing during the initial stage of solidification can enhance wall nucleation and nuclei survival, which leads to the formation of fine-globular primary α(Al). By using semi-solid slurry prepared by LSPSF, direct squeeze cast cup-shaped component with improved mechanical properties such as yield strength of 198MPa, ultimate tensile strength of 306 MPa and elongation of 10.4%, can be obtained.

  20. Surface development of an aluminum brazing sheet during heating studied by XPEEM and XPS

    Science.gov (United States)

    Rullik, L.; Bertram, F.; Niu, Y. R.; Evertsson, J.; Stenqvist, T.; Zakharov, A. A.; Mikkelsen, A.; Lundgren, E.

    2016-10-01

    X-ray photoelectron emission microscopy (XPEEM) was used in combination with other microscopic and spectroscopic techniques to follow the surface development of an aluminum brazing sheet during heating. The studied aluminum alloy sheet is a composite material designed for vacuum brazing. Its surface is covered with a native aluminum oxide film. Changes in the chemical state of the alloying elements and the composition of the surface layer were detected during heating to the melting temperature. It was found that Mg segregates to the surface upon heating, and the measurements indicate the formation of magnesium aluminate. During the heating the aluminum oxide as well as the silicon is observed to disappear from the surface. Our measurements is in agreement with previous studies observing a break-up of the oxide and the outflow of the braze cladding onto the surface, a process assisted by the Mg segregation and reaction with surface oxygen. This study also demonstrates how XPEEM can be utilized to study complex industrial materials.

  1. Adhesion of oxide layer to metal-doped aluminum hydride surface: Density functional calculations

    Science.gov (United States)

    Takezawa, Tomoki; Itoi, Junichi; Kannan, Takashi

    2017-07-01

    The density functional theory (DFT) calculations were carried out to evaluate the adhesion energy of the oxide layer to the metal-doped surface of hydrogen storage material, aluminum hydride (alane, AlH3). The total energy calculations using slab model revealed that the surface doping of some metals to aluminum hydride weakens the adhesion strength of the oxide layer. The influence of titanium, iron, cobalt, and zirconium doping on adhesion strength were evaluated. Except for iron doping, the adhesion strength becomes weak by the doping.

  2. Passivation of the surface of aluminum nanopowders by protective coatings of the different chemical origin

    Science.gov (United States)

    Kwon, Young-Soon; Gromov, Alexander A.; Strokova, Julia I.

    2007-04-01

    The results of investigation and analysis of electro-exploded aluminum nanopowders, whose surface were passivated with the following substances: liquids - nitrocellulose (NC), oleic acid (C 17H 33COOH) and stearic acid (C 17H 35COOH), suspended in kerosene and ethanol, fluoropolymer; solids - boron and nickel; gases - N 2, CO 2 and air (for a comparison) are discussed. The surface protection for the aluminum nanopowders by coatings of different chemical origins leads to the some advantages of the powders properties for an application in energetic systems, e.g. solid propellants and "green" propellants (Al-H 2O). Aluminum nanopowders with a protected surface showed the increased stability to oxidation in air during the storage period and higher reactivity by heating. The TEM-visual diagram of the formation and stabilization of the coatings on the particles has been proposed on the basis of experimental results. The kinetics of the interaction of aluminum nanopowders with air has been discussed. The recommendations concerning an efficiency of the protective "non-Al 2O 3" layers on aluminum nanoparticles were proposed.

  3. Photoluminescence emission of nanoporous anodic aluminum oxide films prepared in phosphoric acid

    Science.gov (United States)

    Nourmohammadi, Abolghasem; Asadabadi, Saeid Jalali; Yousefi, Mohammad Hasan; Ghasemzadeh, Majid

    2012-12-01

    The photoluminescence emission of nanoporous anodic aluminum oxide films formed in phosphoric acid is studied in order to explore their defect-based subband electronic structure. Different excitation wavelengths are used to identify most of the details of the subband states. The films are produced under different anodizing conditions to optimize their emission in the visible range. Scanning electron microscopy investigations confirm pore formation in the produced layers. Gaussian analysis of the emission data indicates that subband states change with anodizing parameters, and various point defects can be formed both in the bulk and on the surface of these nanoporous layers during anodizing.

  4. 由废铝制备明矾及其组成测定%Preparation and determination of potassium aluminum sulfate from waste aluminum

    Institute of Scientific and Technical Information of China (English)

    程相春

    2011-01-01

    以生活废铝易拉罐为原料,采用不同的方法制备明矾,通过XRD、TG、EDTA配位法、重量法等对产物进行了表征,获得了很好的结果.%Potassium aluminum sulfate were prepared by different ways used pop can as material, the complexes were characterized by XRD,TG and EDTA coordination and weight method, and the result is satisfying.

  5. P-type poly-Si prepared by low-temperature aluminum-induced crystallization and doping for solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Yasuhiro; Yu, Zhenrui; Morales-Acevedo, Arturo [CINVESTAV-IPN, Mexico, D.F. (Mexico)

    2000-07-01

    P-type poly-Si thin films prepared by low temperature aluminum-induced crystallization and doping are reported. The starting material was boron-doped a-Si:H prepared by PECVD on glass substrates. Aluminum layers with different thickness were evaporated on a-Si:H surface and conventional thermal annealing was performed at temperatures ranging from 300 to 550 Celsius degrees. XRD, SIMS, and Hall effect measurements were carried out to characterize the annealed Al could be crystallized at temperature as low as 300 Celsius degrees in 60 minutes. This material has high carrier concentration as well as high Hall mobility and can be used as a p-layer of seed layer for thin film poly-Si solar cells. The technique reported here is compatible with PECVD process. [Spanish] Se informa sobre la preparacion de peliculas delgadas tipo P y Poli-Si mediante la cristalizacion inducida de aluminio a baja temperatura y el dopado. El material inicial era de boro dopado y a-Si:H preparado PECVD sobre substratos de vidrio. Se evaporaron capas de aluminio de diferente espesor sobre una superficie de a-Si:H y se llevo a cabo un destemplado termico convencional a temperaturas que varian entre 300 y 500 grados Celsius. Se llevaron a cabo mediciones de XRB, SIMS y del efecto Hall para caracterizar el aluminio destemplado para que pudiera ser cristalizado a temperaturas tan bajas como 300 grados Celsius en 60 minutos. Este material tiene una alta concentracion portadora asi como una alta movilidad Hall y puede usarse como una capa de semilla para celdas solares de pelicula delgada Poli-Si. La tecnica reportada aqui es compatible con el proceso PECVD.

  6. Microstructural and Hardness Study of Pulsed Nd:YAG Laser Surface Alloyed Aluminum with Iron

    Science.gov (United States)

    Ansari, Mohammad; Soltani, Reza; Heydarzadeh Sohi, Mahmoud; Valefi, Zia

    2016-04-01

    In the present study, the feasibility of the formation of surface layers containing hard iron aluminides on AA6061-T6 aluminum via pre-plasma spraying with iron and subsequently double surface melting by pulsed Nd:YAG laser is studied. The effects of single and double laser surface melting on microstructure, phase formation, and hardness of the treated layers are examined. Single-step laser treatment resulted in the presence of undissolved iron particles surrounded by lump-like Al5Fe2 and needle-like Al3Fe intermetallic compounds. Double laser surface melting dissolved the retained undissolved irons and resulted in the formation of Al-Al3Fe eutectic structure. Microhardness profiles along cross section and top surface of the treated layers indicated that laser surface alloying with iron enhanced the hardness of the aluminum to more than twice of that of the base material.

  7. Effect of shock wave risetime on material ejection from aluminum surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Asay, J.R.

    1977-09-15

    The effect of shock wave risetime on material ejection in aluminum has been studied for loading stresses of 21 GPa. Uniform loading was accomplished with plate impact techniques by mounting specimens on a ramp wave generator. Projectile impact on one side of the wave generator produced a wave which dispersed with propagation distance. This wave was then made incident to an aluminum specimen, so that the specimen experienced non-shock loading. It was found that mass ejection from aluminum surfaces can be reduced by over two orders of magnitude relative to shock loading conditions by accelerating the surface with a wave risetime greater than about 35 ns. These results suggest an explanation for the apparent discrepancies which are sometimes observed in mass ejection measurements utilizing either plate impact or electron beam deposition to generate stress waves.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-03-25

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

  9. Ester oxidation on an aluminum surface using chemiluminescence

    Science.gov (United States)

    Jones, William R., Jr.; Meador, Michael A.; Morales, Wilfredo

    1986-01-01

    The oxidation characteristics of a pure ester (trimethyolpropane triheptanoate) were studied by using a chemiluminescence technique. Tests were run in a thin film microoxidation apparatus with an aluminum alloy catalyst. Conditions included a pure oxygen atmosphere and a temperature range of 176 to 206 C. Results indicated that oxidation of the ester (containing .001 M diphenylanthracene as an intensifier) was accompanied by emission of light. The maximum intensity of light emission was a function of the amount of ester, the concentration of intensifier, and the test temperature. The induction period, or the time to reach one-half of maximum intensity was inversely proportional to test temperature. Decreases in light emission at the later stages of a test were caused by depletion of the intensifier.

  10. 40 CFR 63.5755 - How do I demonstrate compliance with the aluminum recreational boat surface coating spray gun...

    Science.gov (United States)

    2010-07-01

    ... the aluminum recreational boat surface coating spray gun cleaning work practice standards? 63.5755... surface coating spray gun cleaning work practice standards? You must demonstrate compliance with the aluminum coating spray gun cleaning work practice standards by meeting the requirements of paragraph (a) or...

  11. Preparation of amorphous aluminum oxide-hydroxide nanoparticles in amphiphilic silicone-based copolymer microemulsions.

    Science.gov (United States)

    Berkovich, Yana; Aserin, Abraham; Wachtel, Ellen; Garti, Nissim

    2002-01-01

    Organo-inorgano nanocomposites with colloidal dimensions have interesting optical, catalytic, and mechanical properties, particularly when such hybrids are reinforced with transition metal oxide nanoparticles. Nanoparticles with a mean size of 1.0-2.4 nm are obtained through hydrolysis of aluminum isopropoxide in the L(2) phase of amphiphilic (PDMS-POE) polydimethylsiloxane-polyoxyethylene Silwet L-7607-octanol/acetylacetone-water mixtures. The particle sizes are related weakly to the microemulsion composition: 0.8-1.2 nm for 20 wt% Silwet L-7607 and 2.0-2.4 nm for 50 wt% Silwet L-7607. Protection of the particles against aggregation is ensured through their confinement in the intraaggregate colloidal domains. Factors affecting the hydrolysis-condensation process of acetylacetone-complexed aluminum isopropoxide in copolymer-poor and copolymer-rich regions of PDMS-POE W/O microemulsions are studied by Fourier transform infrared spectroscopy, small angle X-ray scattering, and transmission electron microscopy. Prepared nanoparticulate dispersions possess long-term stability and form clear mixtures in different organic polar and nonpolar solvents.

  12. Secondary Solidification Behavior of A356 Aluminum Alloy Prepared by the Self-Inoculation Method

    Directory of Open Access Journals (Sweden)

    Ming Li

    2017-06-01

    Full Text Available Semisolid slurry of A356 aluminum alloy was prepared by Self-Inoculation Method, and the secondary solidification behavior during rheo-diecasting forming process was researched. The results indicate that the component with non-dendritic and uniformly distributed microstructures can be produced by Rheo-Diecasting (RDC process (combining Self-inoculation Method (SIM with High Pressure Die Casting (HPDC. The isothermal holding time of the slurry has large effect on primary particles, but has little effect on secondary particles. Growth rate of the primary particles in the isothermal holding process conforms to the dynamic equation of Dt3 − D03 = Kt. The suitable holding time for rheo-diecasting of A356 aluminum alloy is 3 min. During filling process, the nucleation occurs throughout the entire remaining liquid, and nuclei grow stably into globular particles with the limited grain size of 6.5μm firstly, then both α1 and α2 particles appear unstable growth phenomenon due to the existence of constitutional undercooling. The average particle sizes and shape factors of both α1 and α2 are decreasing with the increase of filling distance due to different cooling rate in different positions. The growth rate of the eutectic in RDC is 4 times faster than HPDC, which is mainly due to the limitation of α2 particles in RDC process. The average eutectic spacings are decreasing with the increase of filling distance.

  13. Laser Surface Alloying of Copper, Manganese, and Magnesium with Pure Aluminum Substrate

    Science.gov (United States)

    Jiru, Woldetinsay G.; Sankar, M. Ravi; Dixit, Uday S.

    2016-03-01

    Laser surface alloying is one of the recent technologies used in the manufacturing sector for improving the surface properties of the metals. Light weight materials like aluminum alloys, titanium alloys, and magnesium alloys are used in the locomotive, aerospace, and structural applications. In the present work, an experimental study was conducted to improve the surface hardness of commercially pure aluminum plate. CO2 laser is used to melt pre-placed powders of pure copper, manganese, and magnesium. Microstructure of alloyed surface was analyzed using optical microscope. The best surface alloying was obtained at the optimum values of laser parameters, viz., laser power, scan speed, and laser beam diameter. In the alloyed region, microhardness increased from 30 HV0.5 to 430 HV0.5, while it was 60 HV0.5 in the heat-affected region. Tensile tests revealed some reduction in the strength and total elongation due to alloying. On the other hand, corrosion resistance improved.

  14. Nicotine-magnesium aluminum silicate microparticle surface modified with chitosan for mucosal delivery

    DEFF Research Database (Denmark)

    Kanjanakawinkul, Watchara; Rades, Thomas; Puttipipatkhachorn, Satit

    2013-01-01

    Magnesium aluminum silicate (MAS), a negatively charged clay, and nicotine (NCT), a basic drug, can interact electrostatically to form microparticles. Chitosan (CS) was used for the surface modification of the microparticles, and a lyophilization method was used to preserve the original particle...

  15. Laser surface alloying of aluminum (AA1200) with Ni and SiC Powders

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB

    2010-12-01

    Full Text Available An Nd:YAG laser was used for surface alloying of aluminum AA1200. The alloying powder was a mixture of Ni and SiC in different ratios. A study of the microstructures obtained after alloying was conducted using optical and scanning electron...

  16. A novel method for preparation of 8-hydroxyquinoline functionalized mesoporous silica: Aluminum complexes and photoluminescence studies

    Science.gov (United States)

    Badiei, Alireza; Goldooz, Hassan; Ziarani, Ghodsi Mohammadi

    2011-03-01

    8-Hydroxyquinoline (8-HQ) was attached to mesoporous silica by sulfonamide bond formation between 8-hydroxyquinoline-5-sulfonyl chloride (8-HQ-SO 2Cl) and aminopropyl functionalized SBA-15 (designated as SBA-SPS-Q) and then aluminum complexes of 8-HQ was covalently bonded to SBA-SPS-Q using coordinating ability of grafted 8-HQ.The prepared materials were characterized by powder X-ray diffraction (XRD), nitrogen adsorption-desorption, Fourier transform infrared (FT-IR), thermal analysis (TGA-DTA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), elemental analysis and fluorescence spectra. The environmental effects on the emission spectra of grafted 8-HQ and its complexes were studied and discussed in details.

  17. Annulus electromagnetic stirring for preparing semisolid A357 aluminum alloy slurry

    Institute of Scientific and Technical Information of China (English)

    BAI Yue-long; XU Jun; ZHANG Zhi-feng; SHI Li-kai

    2009-01-01

    The effects of pouring temperature and annulus gap width on the microstructure of the semi-solid A357 aluminum alloy slurry prepared by annulus electromagnetic stirring(AEMS) technology were investigated. The results show that low pouring temperature and narrow annulus gap are advantageous to obtaining the small spherical primary α(Al) phase. The lower the pouring temperature is and the smaller the annulus gap width is, the more uniform, the smaller and the more spherical the microstructure is. The microstructures obtained by the ordinary electromagnetic stirring and AEMS were compared. The results indicate that the primary α(Al) particles are globular, small and distribute homogeneously in the slurry obtained by AEMS. But in the slurry obtained by the ordinary electromagnetic stirring, the primary α(Al) particles are small dendrites in the edge of the slurry and they are large and rosette-like or dendritic in the inner of the slurry.

  18. The Influence of Surface Anisotropy Crystalline Structure on Wetting of Sapphire by Molten Aluminum

    Science.gov (United States)

    Aguilar-Santillan, Joaquin

    2013-05-01

    The wetting of sapphire by molten aluminum was investigated by the sessile drop technique from 1073 K to 1473 K (800 °C to 1200 °C) at PO2 <10-15 Pa under Ar atmosphere. This study focuses on sapphire crystalline structure and its principle to the interface. The planes " a" and " b" are oxygen terminated structures and wet more by Al, whereas the " c" plane is an aluminum terminated structure. A wetting transition at 1273 K (1000 °C) was obtained and a solid surface tension proves the capillarity trends of the couple.

  19. Material ejection from shock-loaded free surfaces of aluminum and lead

    Energy Technology Data Exchange (ETDEWEB)

    Asay, J.R.

    1976-10-01

    A discussion is presented regarding interferometer experiments conducted on free surfaces which are impulsively loaded with high amplitude shock waves. It is shown that material ejection from shocked surfaces can significantly degrade interferometer experiments. In particular, loss of both light intensity and contrast of interferometer signals can result from various scattering and absorption processes occurring in a cloud of ejected material. An experimental technique is presented which allows determination of the mass and velocity of material ejected from free surfaces during shock loading. The technique has been applied to a study of mass ejection occurring naturally from shocked surfaces of two aluminium alloys and from lead. These results show that the total ejected mass ranges from a few ..mu..g/cm/sup 2/ in the aluminum alloys studied to a few mg/cm/sup 2/ in lead, for shock pressures ranging from about 10 to 50 GPa (100 to 500 kbar). Surface defects, such as pits and scratches, are thought to strongly influence mass ejection in aluminum; whereas in lead, localized shock-induced melting and vaporization are thought to be the dominant mechanisms at the higher shock pressures. Experimental results are also presented for aluminum surfaces which contain artificial defects in the form of wedge-shaped cavities. These results show that the maximum ejecta velocities of approximately two to four times the free surface velocity which are observed in these experiments can be correlated with predictions of steady jetting theory.

  20. Interface properties and phase formation between surface coated SKD61 and aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    Se-Weon CHOI; Young-Chan KIM; Se-Hun CHANG; Ik-Hyun OH; Joon-Sik PARK; Chang-Seog KANG

    2009-01-01

    The intermediate phase formation and surface protection effects between SKD61 die mold alloys and aluminum alloys were investigated during a simulated die-casting process. The surface coatings of SKD61 alloy were carried out via Si pack cementation coatings at 900 ℃ for 10 h and the e-FeSi phase formed. When the coated SKD61 alloy was dipped in the liquid aluminum alloy (ALDC12), the surface coated SKD61 alloys showed better surface properties compared with uncoated SKD61 alloys, i.e., the intermediate phases (FeSiAl compound) were not produced for the coated SKD61 alloy. The coating layer of e-FeSi served as a diffusion barrier for the formation of FeSiAl compounds.

  1. Boric Acid as an Accelerator of Cerium Surface Treatment on Aluminum

    Directory of Open Access Journals (Sweden)

    K. Cruz-Hernández

    2014-01-01

    Full Text Available Aluminum pieces are often used in various industrial processes like automotive and aerospace manufacturing, as well as in ornamental applications, so it is necessary to develop processes to protect these materials, processes that can be industrialized to protect the aluminum as well or better than chromate treatments. The purpose of this research is to evaluate boric acid as an accelerator by optimizing its concentration in cerium conversion coatings (CeCC with 10-minute immersion time with a concentration of 0.1 g L−1 over aluminum to protect it. The evaluation will be carried out by measuring anticorrosion properties with electrochemical techniques (polarization resistance, Rp, polarization curves, PC, and electrochemical impedance spectroscopy, EIS in NaCl 3.5% wt. aqueous solution and surface characterization with scanning electron microscopy (SEM.

  2. An investigation on the compressibility of aluminum/nano-alumina composite powder prepared by blending and mechanical milling

    Energy Technology Data Exchange (ETDEWEB)

    Razavi Hesabi, Z. [Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, Tehran 14588 (Iran, Islamic Republic of); Hafizpour, H.R. [Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, Tehran 14588 (Iran, Islamic Republic of); Simchi, A. [Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, Tehran 14588 (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, Tehran 14588 (Iran, Islamic Republic of)], E-mail: simchi@sharif.edu

    2007-04-25

    The densification response of aluminum powder reinforced with 5 vol.% nanometric alumina particles (35 nm) during uniaxial compaction in a rigid die was studied. The composite powder was prepared by blending and mechanical milling procedures. To determine the effect of the reinforcement nanoparticles on the compressibility of aluminum powder, monolithic Al powder, i.e. without the addition of alumina, was also examined. It was shown that at the early stage of compaction when the rearrangement of particles is the dominant mechanism of the densification, disintegration of the nanoparticle clusters and agglomerates under the applied load contributes in the densification of the composite powder prepared by blending method. As the compaction pressure increases, however, the load partitioning effect of the nanoparticles decreases the densification rate of the powder mixture, resulting in a lower density compared to the monolithic aluminum. It was also shown that mechanical milling significantly impacts the compressibility of the unreinforced and reinforced aluminum powders. Morphological changes of the particles upon milling increase the contribution of particle rearrangement in densification whilst the plastic deformation mechanism is significantly retarded due to the work-hardening effect of the milling process. Meanwhile, the distribution of alumina nanoparticles is improved by mechanical milling, which in fact, affects the compressibility of the composite powder. This paper addresses the effect of mechanical milling and reinforcement nanoparticles on the compressibility of aluminum powder.

  3. Evolution of Surface Oxide Film of Typical Aluminum Alloy During Medium-Temperature Brazing Process

    Institute of Scientific and Technical Information of China (English)

    程方杰; 赵海微; 王颖; 肖兵; 姚俊峰

    2014-01-01

    The evolution of the surface oxide film along the depth direction of typical aluminum alloy under medium-temperature brazing was investigated by means of X-ray photoelectron spectroscopy (XPS). For the alloy with Mg content below 2.0wt%, whether under cold rolling condition or during medium-temperature brazing process, the en-richment of Mg element on the surface was not detected and the oxide film was pure Al2O3. However, the oxide film grew obviously during medium-temperature brazing process, and the thickness was about 80 nm. For the alloy with Mg content above 2.0wt%, under cold rolling condition, the original surface oxide film was pure Al2O3. However, the Mg element was significantly enriched on the outermost surface during medium-temperature brazing process, and MgO-based oxide film mixed with small amount of MgAl2O4 was formed with a thickness of about 130 nm. The alloy-ing elements of Mn and Si were not enriched on the surface neither under cold rolling condition nor during medium-temperature brazing process for all the selected aluminum alloy, and the surface oxide film was similar to that of pure aluminum, which was almost entire Al2O3.

  4. Preparation of stable silica surfaces for surface forces measurement

    Science.gov (United States)

    Ren, Huai-Yin; Mizukami, Masashi; Kurihara, Kazue

    2017-09-01

    A surface forces apparatus (SFA) measures the forces between two surfaces as a function of the surface separation distance. It is regarded as an essential tool for studying the interactions between two surfaces. However, sample surfaces used for the conventional SFA measurements have been mostly limited to thin (ca. 2-3 μm) micas, which are coated with silver layers (ca. 50 nm) on their back, due to the requirement of the distance determination by transmission mode optical interferometry called FECO (fringes of equal chromatic order). The FECO method has the advantage of determining the absolute distance, so it should be important to increase the availability of samples other than mica, which is chemically nonreactive and also requires significant efforts for cleaving. Recently, silica sheets have been occasionally used in place of mica, which increases the possibility of surface modification. However, in this case, the silver layer side of the sheet is glued on a cylindrical quartz disc using epoxy resin, which is not stable in organic solvents and can be easily swollen or dissolved. The preparation of substrates more stable under severe conditions, such as in organic solvents, is necessary for extending application of the measurement. In this study, we report an easy method for preparing stable silica layers of ca. 2 μm in thickness deposited on gold layers (41 nm)/silica discs by sputtering, then annealed to enhance the stability. The obtained silica layers were stable and showed no swelling in organic solvents such as ethanol and toluene.

  5. Tribological Properties of Aluminum Alloy treated by Fine Particle Peening/DLC Hybrid Surface Modification

    Directory of Open Access Journals (Sweden)

    Nanbu H.

    2010-06-01

    Full Text Available In order to improve the adhesiveness of the DLC coating, Fine Particle Peening (FPP treatment was employed as pre-treatment of the DLC coating process. FPP treatment was performed using SiC shot particles, and then AA6061-T6 aluminum alloy was DLC-coated. A SiC-rich layer was formed around the surface of the aluminum alloy by the FPP treatment because small chips of shot particles were embedded into the substrate surface. Reciprocating sliding tests were conducted to measure the friction coefficients. While the DLC coated specimen without FPP treatment showed a sudden increase in friction coefficient at the early stage of the wear cycles, the FPP/DLC hybrid treated specimen maintained a low friction coefficient value during the test period. Further investigation revealed that the tribological properties of the substrate after the DLC coating were improved with an increase in the amount of Si at the surface.

  6. Iss observations of aluminum surfaces under hydrogen ion bombardment

    Science.gov (United States)

    Sagara, A.; Kamada, K.; Higashida, Y.

    1984-12-01

    The shadowing effect of ISS was applied to observe the surface behavior of H atoms implanted with 500 eV/atom on a high-purity A1 sample. This study confirmed that this technique is powerful to observe the retention kinetics of H atoms especially on the topmost material surface with simultaneous analysis for surface contaminants such as oxygen during irradiation with hydrogen ions. The result obtained from the initially cleaned surface showed a remarkable increase in the H retention with increasing fluence of H2+ up to about 1018 H/cm2 at room temperature, depending on the fluence of predamage given by He+ ions, but showed no increase in the retention at the temperatures above 100 ° C. Therefore, because Al is a metal well known to be passive for chemisorption of H2 molecules and H atoms, it was concluded that the observed H retention originates from the traps produced by radiation damage. The activation energy for thermal desorption of the trapped H atoms was estimated to be 1.1±0.4 eV by ISS measurements. The oxygen-covered surface showed a rapid increase in the retention at fluence of less than 1017 H/cm2.

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

    Science.gov (United States)

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

    1992-01-01

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

  8. Preparation of titanium dioxide films on etched aluminum foil by vacuum infiltration and anodizing

    Science.gov (United States)

    Xiang, Lian; Park, Sang-Shik

    2016-12-01

    Al2O3-TiO2 (Al-Ti) composite oxide films are a promising dielectric material for future use in capacitors. In this study, TiO2 films were prepared on etched Al foils by vacuum infiltration. TiO2 films prepared using a sol-gel process were annealed at various temperatures (450, 500, and 550 °C) for different time durations (10, 30, and 60 min) for 4 cycles, and then anodized at 100 V. The specimens were characterized using X-ray diffraction, field emission scanning electron microscopy, and field emission transmission electron microscopy. The results show that the tunnels of the specimens feature a multi-layer structure consisting of an Al2O3 outer layer, an Al-Ti composite oxide middle layer, and an aluminum hydrate inner layer. The electrical properties of the specimens, such as the withstanding voltage and specific capacitance, were also measured. Compared to specimens without TiO2 coating, the specific capacitances of the TiO2-coated specimens are increased. The specific capacitance of the anode Al foil with TiO2 coating increased by 42% compared to that of a specimen without TiO2 coating when annealed at 550 °C for 10 min. These composite oxide films could enhance the specific capacitance of anode Al foils used in dielectric materials.

  9. Characterization and Catalytic Activity of Titanium-containing Aluminum Phosphate Prepared by Sol-gel and Nonuniform Precipitation for O-Alkylation of Catechol with Ethanol

    Institute of Scientific and Technical Information of China (English)

    PAN Chun-liu; ZHANG Wen-xiang; LI Xue-mei; JIANG Da-zhen; WU Tong-hao

    2003-01-01

    Three titanium-containing aluminum phosphate catalysts with a general formula Al0.77Ti0.23PO4 were prepared by the sol-gel method at room temperature(APTS), and a nonuniform precipitation procedure at room temperature(APTR) and under reflux(APTF), respectively. The structural features and the surface properties of the three catalysts were determined by means of the physical adsorption of nitrogen at liquid N2 temperature, XRD, UV-Vis, NH3-TPD and IR of adsorbed pyridine. The vapor phase O-alkylation of catechol with ethanol over the prepared catalysts was studied. It was found that the activity and the selectivity of these catalysts are greatly dependent on the preparation method, and catalyst APTF shows the highest activity and selectivity. The characterization evidence indicates that the weak Brnsted acid sites were more effective for the reaction.

  10. Curie temperature and magnetic properties of aluminum doped barium ferrite particles prepared by ball mill method

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Daming [Center for Magnetism and Magnetic Nanostructures, University of Colorado at Colorado Springs, 1420 Austin Bluffs Pkwy, Colorado Springs, Colorado 80918 (United States); College of Materials and Chemical Engineering, Hainan University, Haikou 570228, Hainan (China); Harward, Ian; Baptist, Joshua; Goldman, Sara; Celinski, Zbigniew [Center for Magnetism and Magnetic Nanostructures, University of Colorado at Colorado Springs, 1420 Austin Bluffs Pkwy, Colorado Springs, Colorado 80918 (United States)

    2015-12-01

    Barium ferrite has attracted considerable interest in the fields of permanent magnets and perpendicular magnetic recording due to its strong uniaxial anisotropy and high Curie temperature (T{sub c}). We prepared aluminum doped barium ferrite ceramics (BaAl{sub x}Fe{sub 12−x}O{sub 19}, 0≤x≤6) by the ball mill method. The powder was milled for 96 h, and after forming pellets, annealed for 48 h in air at 1000 °C. The X-ray diffraction (XRD) data show that there are only single hexagonal phases in the samples without any impurity phase. The crystal lattice constants, a and c, were calculated by Cohen's method. Both a and c decrease with increasing x, ranging from 0.588 nm and 2.318 nm to 0.573 nm and 2.294 nm, respectively. A Vibrating Sample Magnetometer (VSM) and Superconducting Quantum Interference Device (SQUID) were used to investigate T{sub c} and magnetic properties of BaFe{sub 12−x}Al{sub x}O{sub 19}. It is found that T{sub c} decreases with increasing x, from 425 °C to 298 °C. It is also found that the saturated magnetization (4πM{sub s}) decreases with increasing x, while the coercivity (H{sub c}) increases with the increase in x. The anisotropy field was also determined from the SQUID measurement. - Highlights: • The Curie temperature and magnetic properties of aluminum doped barium ferrite particles were studied systemically. • The relation between 4πM{sub s} and composition x at 50 K (both experimental value and theoretical calculation) was revealed. • Occupation number for spin up and spin down as a function of temperature was shown. • The relation between 4πM{sub s} and composition x from 50 K to room temperature was revealed.

  11. Influence of the surface pre-treatment of aluminum on the processes of formation of cerium oxides protective films

    Science.gov (United States)

    Andreeva, R.; Stoyanova, E.; Tsanev, A.; Stoychev, D.

    2016-03-01

    It is known that there is special interest in the contemporary investigations on conversion treatment of aluminum aimed at promoting its corrosion stability, which is focused on electrolytes on the basis of salts of metals belonging to the group of rare-earth elements. Their application is especially attractive, as it enables a successful substitution of the presently applied highly efficient, but at the same time toxic Cr6+-containing electrolytes. The present paper presents a study on the influence of the preliminary alkaline activation and acidic de-oxidation of the aluminum surface on the processes of immersion formation of protective cerium oxides films on Al 1050. The results obtained show that their deposition from simple electrolytes (containing only salts of Ce3+ ions) on the Al surface, treated only in alkaline solution, occurs at a higher rate, which leads to preparing thicker oxide films having a better protective ability. In the cases when the formation of oxide films is realized in a complex electrolyte (containing salts of Ce3+ and Cu2+ ions), better results are obtained with respect to the morphology and protective action of cerium oxides film on samples that have been consecutively activated in alkaline solution and deoxidized in acidic solution. Electrochemical investigations were carried out in a model corrosion medium (0.1 M NaCl); it was shown that the cerium protective films, deposited by immersion, have a cathodic character with regard to the aluminum support and inhibit the occurrence of the depolarizing corrosion process -- the reaction of oxygen reduction.

  12. Preparation Methods for Aluminum Matrix Composite%铝基复合材料的制备方法

    Institute of Scientific and Technical Information of China (English)

    倪增磊; 王爱琴; 田可庆

    2011-01-01

    The pressureless infiltration process for the preparation of high volume fraction SiC/Al composite, vacuum canning hot-extrusion process and spray deposition technology process for the preparation of high-silicon aluminum composite were reviewed. The development trends for the preparation of aluminum composite material were looked forward.%综述了无压浸渗法制备高体积分数SiC/Al复合材料,以及粉末真空包套热挤压和喷射沉积工艺制备高硅含量铝基复合材料的方法,同时展望了制备铝基复合材料的发展趋势.

  13. Nano-engineering of superhydrophobic aluminum surfaces for anti-corrosion

    Science.gov (United States)

    Jeong, Chanyoung

    Metal corrosion is a serious problem, both economically and operationally, for engineering systems such as aircraft, automobiles, pipelines, and naval vessels. In such engineering systems, aluminum is one of the primary materials of construction due to its light weight compared to steel and good general corrosion resistance. However, because of aluminum's relatively lower resistance to corrosion in salt water environments, protective measures such as thick coatings, paints, or cathodic protection must be used for satisfactory service life. Unfortunately, such anti-corrosion methods can create other concerns, such as environmental contamination, protection durability, and negative impact on hydrodynamic efficiency. Recently, a novel approach to preventing metal corrosion has emerged, using superhydrophobic surfaces. Superhydrophobic surfaces create a composite interface to liquid by retaining air within the surface structures, thus minimizing the direct contact of the liquid environment to the metal surface. The result is a highly non-wetting and anti-adherent surface that can offer other benefits such as biofouling resistance and hydrodynamic low friction. Prior research with superhydrophobic surfaces for corrosion applications was based on irregular surface roughening and/or chemical coatings, which resulted in random surface features, mostly on the micrometer scale. Such microscale surface roughness with poor controllability of structural dimensions and shapes has been a critical limitation to deeper understanding of the anti-corrosive effectiveness and optimized application of this approach. The research reported here provides a novel approach to producing controlled superhydrophobic nanostructures on aluminum that allows a systematic investigation of the superhydrophobic surface parameters on the corrosion resistance and hence can provide a route to optimization of the surface. Electrochemical anodization is used to controllably modulate the oxide layer

  14. Investigations of Aluminum-Doped Self-Healing Zircaloy Surfaces in Context of Accident-Tolerant Fuel Cladding Research

    Science.gov (United States)

    Carr, James; Vasudevamurthy, Gokul; Snead, Lance; Hinderliter, Brian; Massey, Caleb

    2016-06-01

    We present here some important results investigating aluminum as an effective surface dopant for increased oxidation resistance of zircaloy nuclear fuel cladding. At first, the transport behavior of aluminum into reactor grade zircaloy was studied using simple diffusion couples at temperatures greater than 770 K. The experiments revealed the formation of tens of microns thick graded Zr-Al layers. The activation energy of aluminum in zircaloy was found to be ~175 kJ/mol (~1.8 eV), indicating the high mobility of aluminum in zircaloy. Subsequently, aluminum sputter-coated zircaloy coupons were heat-treated to achieve surface doping and form compositionally graded layers. These coupons were then tested in steam environments at 1073 and 1273 K. The microstructure of the as-fabricated and steam-corroded specimens was compared to those of pure zircaloy control specimens. Analysis of data revealed that aluminum effectively competed with zircaloy for oxygen up until 1073 K blocking oxygen penetration, with no traces of large scale spalling, indicating mechanically stable interfaces and surfaces. At the highest steam test temperatures, aluminum was observed to segregate from the Zr-Al alloy under layers and migrate to the surface forming discrete clusters. Although this is perceived as an extremely desirable phenomenon, in the current experiments, oxygen was observed to penetrate into the zirconium-rich under layers, which could be attributed to formation of surface defects such as cracks in the surface alumina layers.

  15. Vibration characteristics of aluminum surface subjected to ultrasonic waves and their effect on wetting behavior of solder droplets.

    Science.gov (United States)

    Ma, Lin; Xu, Zhiwu; Zheng, Kun; Yan, Jiuchun; Yang, Shiqin

    2014-03-01

    The vibration characteristics of an aluminum surface subjected to ultrasonic waves were investigated with a combination of numerical simulation and experimental testing. The wetting behavior of solder droplets on the vibrating aluminum surface was also examined. The results show that the vibration pattern of the aluminum surface is inhomogeneous. The amplitude of the aluminum surface exceeds the excitation amplitude in some zones, while the amplitude decreases nearly to zero in other zones. The distribution of the zero-amplitude zones is much less dependent on the strength of the vibration than on the location of the vibration source. The surface of the liquid solder vibrates at an ultrasonic frequency that is higher than the vibration source, and the amplitude of the liquid solder is almost twice that of the aluminum surface. The vibration of the surface of the base metal (liquid solder) correlates with the oxide film removal effect. Significant removal of the oxide film can be achieved within 2s when the amplitude of the aluminum surface is higher than 5.4 μm or when the amplitude of the liquid solder surface is higher than 10.2 μm.

  16. Thermal oxidation of the surface of binary aluminum alloys with rare-earth metals

    Science.gov (United States)

    Akashev, L. A.; Popov, N. A.; Kuznetsov, M. V.; Shevchenko, V. G.

    2015-05-01

    The kinetics of oxidation of the surface of Al alloys with 1-2.5 at % rare-earth metals (REMs) at 400-500°C in air was studied by ellipsometry and X-ray photoelectron spectroscopy (XPS). The addition (1-2.5 at % REM) of all rare-earth metals to aluminum was shown to increase the thickness of the oxide layer. The addition of surfactant and chemically active REMs (Yb, Sm, La, and Ce) increased the rate of oxidation of solid aluminum most effectively. The oxidation can be accelerated by the polymorphic transformations of the individual REM oxides in the film. The surface activity of Sm with respect to solid Al was confirmed by XRS.

  17. Binary collision model for neon Auger spectra from neon ion bombardment of the aluminum surface

    Science.gov (United States)

    Pepper, S. V.

    1986-01-01

    A model is developed to account for the angle-resolved Auger spectra from neon ion bombardment of the aluminum surface recently obtained by Pepper and Aron. The neon is assumed to be excited in a single asymmetric neon-aluminum-collision and scattered back into the vacuum where it emits an Auger electron. The velocity of the Auger electron acquires a Doppler shift by virtue of the emission from a moving source. The dependence of the Auger peak shape and energy on the incident ion energy, angle of incidence and on the angle of Auger electron emission with respect to the surface is presented. Satisfactory agreement with the angle resolved experimental observations is obtained. The dependence of the angle-integrated Auger yield on the incident ion energy and angle of incidence is also obtained and shown to be in satisfactory agreement with available experimental evidence.

  18. Wetting of the (0001) α-Al2O3 Sapphire Surface by Molten Aluminum: Effect of Surface Roughness

    Science.gov (United States)

    Aguilar-Santillan, Joaquin

    2010-03-01

    The wetting of molten aluminum on the “ c”-plane (0001) of single-crystal α-Al2O3 (sapphire) was studied by the sessile drop technique from 800 °C (1073 K) to 1200 °C (1473 K). Systematically increasing the (0001) surface roughness by SiC abrasion increased the wetting contact angle, resulting in reduced wetting. The surface roughness factor R originally defined by Wenzel, was determined as a function of the abrasion, temperature, and time. The wetting decreases as the surface roughness increases. Rough surfaces also create time and temperature effects on wetting, changing those for a smoothly polished surface. The existence of a high-temperature surface structural transition for (0001) of α-Al2O3, which has been previously suggested, was confirmed. Increased roughness R accents the effect of the surface structural transition, increasing the wetting contact angle changes during the transition.

  19. One-step fabrication of near superhydrophobic aluminum surface by nanosecond laser ablation

    Science.gov (United States)

    Jagdheesh, R.; García-Ballesteros, J. J.; Ocaña, J. L.

    2016-06-01

    Inspired by the micro and nano structures of biological surface such as lotus leaf, rice leaves, etc. a functional near superhydrophobic surface of pure aluminum has been fabricated using one-step nanosecond laser processing. Thin aluminum sheets are micro-patterned with ultraviolet laser pulses to create near superhydrophobic surface in one-step direct laser writing technique. The impact of number of pulses/microhole with respect to the geometry and static contact angle measurements has been investigated. The microstructure shows the formation of blind microholes along with the micro-wall by laser processing, which improves the composite interface between the three phases such as water, air and solid, thus enhance the wetting property of the surface. The geometrical changes are supported by the chemical changes induced on the surface for improving the degree of hydrophobicity. Laser processed microholes exhibited near superhydrophobic surface with SCA measurement of 148 ± 3°. The static contact angle values are very consistent for repeated measurement at same area and across the laser patterned surface.

  20. Preparation of Aluminum Foam Sandwich by Rolling-bonding/Powder Metallurgy Foaming Technology

    Institute of Scientific and Technical Information of China (English)

    ZU Guoyin; SONG Binna; GUAN Zhihao; WANG Lei; YAO Guangchun

    2011-01-01

    Aluminum foam sandwich was prepared by rolling-bonding/powder metallurgical foaming technology,and the effects of rolling on bond strength of face sheet/powders and powder density were studied.Moreover,the foaming agent,TiH2,was heat treated and a certain amount of Mg was added into powder in an attempt to understand how the stability and uniformity of foam was improved.The experimental results show that the foaming precursors with ideal quality were obtained by rolling-bonding process.When rolling reduction is 67%,the consistency of powders reach to 99.87%.Throughout consideration of the bonding of face sheet/core layer powders and deformation characteristic of powders,the optimum rolling reduction is 60%-70%.Cracks and drainage during foaming were inhibited by heat treatment of foaming agent TiH2 and the addition of a certain amount of Mg.The optimum heat treatment way of TiH2 is that heat preserving 1 hour at 450 ℃;the amount of adding Mg is 1wt%.

  1. Curie temperature and magnetic properties of aluminum doped barium ferrite particles prepared by ball mill method

    Science.gov (United States)

    Chen, Daming; Harward, Ian; Baptist, Joshua; Goldman, Sara; Celinski, Zbigniew

    2015-12-01

    Barium ferrite has attracted considerable interest in the fields of permanent magnets and perpendicular magnetic recording due to its strong uniaxial anisotropy and high Curie temperature (Tc). We prepared aluminum doped barium ferrite ceramics (BaAlxFe12-xO19, 0≤x≤6) by the ball mill method. The powder was milled for 96 h, and after forming pellets, annealed for 48 h in air at 1000 °C. The X-ray diffraction (XRD) data show that there are only single hexagonal phases in the samples without any impurity phase. The crystal lattice constants, a and c, were calculated by Cohen's method. Both a and c decrease with increasing x, ranging from 0.588 nm and 2.318 nm to 0.573 nm and 2.294 nm, respectively. A Vibrating Sample Magnetometer (VSM) and Superconducting Quantum Interference Device (SQUID) were used to investigate Tc and magnetic properties of BaFe12-xAlxO19. It is found that Tc decreases with increasing x, from 425 °C to 298 °C. It is also found that the saturated magnetization (4πMs) decreases with increasing x, while the coercivity (Hc) increases with the increase in x. The anisotropy field was also determined from the SQUID measurement.

  2. Effect of Orifice Diameter on Bubble Generation Process in Melt Gas Injection to Prepare Aluminum Foams

    Science.gov (United States)

    Yuan, Jianyu; Li, Yanxiang; Wang, Ningzhen; Cheng, Ying; Chen, Xiang

    2016-06-01

    The bubble generation process in conditioned A356 alloy melt through submerged spiry orifices with a wide diameter range (from 0.07 to 1.0 mm) is investigated in order to prepare aluminum foams with fine pores. The gas flow rate and chamber pressure relationship for each orifice is first determined when blowing gas in atmospheric environment. The effects of chamber pressure ( P c) and orifice diameter ( D o) on bubble size are then analyzed separately when blowing gas in melt. A three-dimensional fitting curve is obtained illustrating both the influences of orifice diameter and chamber pressure on bubble size based on the experimental data. It is found that the bubble size has a V-shaped relationship with orifice diameter and chamber pressure neighboring the optimized parameter ( D o = 0.25 mm, P c = 0.4 MPa). The bubble generation mechanism is proposed based on the Rayleigh-Plesset equation. It is found that the bubbles will not be generated until a threshold pressure difference is reached. The threshold pressure difference is dependent on the orifice diameter, which determines the time span of pre-formation stage and bubble growth stage.

  3. Preparation and Properties of a Novel Al-Si-Ge-Zn Filler Metal for Brazing Aluminum

    Science.gov (United States)

    Niu, Zhiwei; Huang, Jihua; Yang, Hao; Chen, Shuhai; Zhao, Xingke

    2015-06-01

    The study is concerned with developing a filler metal with low melting temperature and good processability for brazing aluminum and its alloys. For this purpose, a novel Al-Si-Ge-Zn alloy was prepared according to Al-Si-Ge and Al-Si-Zn ternary phase diagrams. The melting characteristics, microstructures, wettability, and processing property of the alloy were investigated. The results showed that the melting temperature range of the novel filler metal was 505.2-545.1 °C, and the temperature interval between the solidus and the liquidus was 39.9 °C. Compared with a common Al-Si-Ge alloy, it had smaller and better dispersed β-GeSi solid solution precipitates, and the Zn-rich phases distributed on the boundary of the β-GeSi precipitates. The novel filler metal has good processability and good wettability with Al. There was one obvious transition layer with a thin α-Al solid solution between the filler metal and base metal, which is favorable to improve the strength of brazing joint.

  4. Preparation of Neodymium-Doped Yttrium Aluminum Garnet Transparent Ceramics by Homogeneous Precipitation Method

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Neodymium doped-yttrium aluminum garnet (Nd: YAG) transparent polycrystalline ceramics already become substitutes of single crystals because they are provided with easy fabrication, low cost, large size, highly doped concentration, high heat conductivity, mass fabrication, multi-layers and multi-functions. The Nd: YAG precursor powders with loosely dispersed, slightly agglomerated, super fine and YAG cubic crystal phase were synthesized at 1100 ℃ by the hocal stabilizer, TEOS as sintering additive. The Nd:YAG transparent ceramics were prepared after being vacuum sintered at 1700 ℃ for 5 h. The Nd:YAG ceramic materials were characterized by the TG-DTA, XRD, FT-IR, TEM, FEG-ESEM and FT-PL. The results show that the crystallization temperature of YAG is 850 ℃ and the intermediate crystal phase YAP forming during the heat treatment transforms to YAG cubic crystal phase at 1050 ℃. The lasing wavelength of (Nd0.01Y0.99)3Al5O12 transparent ceramics is 1.065 μm and there exists a slight red-shift compared to the single crystal with the same chemical composition. The optical transmittance is 45% in the visible light and 58% in the near infrared light and the optical transmittance descends with the decreasing the wavelength.

  5. Steam reforming of methanol over copper loaded anodized aluminum oxide (AAO) prepared through electrodeposition

    Science.gov (United States)

    Linga Reddy, E.; Karuppiah, J.; Lee, Hyun Chan; Kim, Dong Hyun

    2014-12-01

    In order to study the steam reforming of methanol (SRM) to produce hydrogen for fuel cells, porous γ-alumina support is developed on Al substrate using anodic oxidation process and copper catalyst particles are deposited homogeneously over anodic aluminum oxide (AAO) surface by electrodeposition method. We investigated the effect of electrodeposition time and hot water treatment (HWT) on the activity of catalysts for SRM reaction in the temperature range between 160 and 360 °C. The experimental results indicate that the SRM activity, CO2 and dimethyl ether (DME) selectivity's over Cu catalysts increased as the electrodeposition time increased from 30 to 120 s, further increment in deposition time of Cu have no significant effect on it. The rates of SRM conversion are found to be higher for the catalysts made from the supports obtained after HWT, which may be due to the enhancement in the surface area of AAO support. It is found that the SRM activity and CO2 selectivity strongly depended upon the free exposed copper sites available for methanol adsorption and reaction, and DME in products is mainly observed in the reaction temperature range between 300 and 350 °C and it is higher for the catalysts with low Cu content.

  6. Dioxygen molecule adsorption and oxygen atom diffusion on clean and defective aluminum(111) surface using first principles calculations

    Science.gov (United States)

    Guiltat, Mathilde; Brut, Marie; Vizzini, Sébastien; Hémeryck, Anne

    2017-03-01

    First principles calculations are conducted to investigate kinetic behavior of oxygen species at the surface of clean and defective Al(111) substrate. Oxygen island, aluminum vacancy, aluminum sub-vacancy, aluminum ad-atom and aluminum terraces defects are addressed. Adsorption of oxygen molecule is first performed on all these systems resulting in dissociated oxygen atoms in main cases. The obtained adsorbed configurations are then picked to study the behavior of atomic oxygen specie and get a detailed understanding on the effect of the local environment on the ability of the oxygen atom to diffuse on the surface. We pointed out that local environment impacts energetics of oxygen atom diffusion. Close packed oxygen island, sub-vacancy and ad-atoms favor oxygen atom stability and decrease mobility of oxygen atom on the surface, to be seen as surface area for further nucleation of oxygen island.

  7. Fractal Characteristics and Fractal Dimension Measurement on Broken Surfaces of Aluminum Electric Porcelain

    Institute of Scientific and Technical Information of China (English)

    YANG Zhiyuan; ZHOU Anning

    2005-01-01

    The characteristics of broken surfaces were researched by a scanning electron microscope (SEM) and a reflection microscope, and the fractal dimensions of broken surfaces were measured by the Slit Island method. The experimental results indicate that the broken surface of aluminum electric porcelain is a fractal body in statistics, and the fractal dimensions of broken surfaces are different with the different amplification multiple value.In all of measured fractal dimensions,both of values measured in 100× under reflection microscope and in 500× under SEM are maximum, whereas the values measured in 63× under reflection microscope and in 2000× under SEM are obviously minimum. The fractal dimensions of broken surfaces are also affected by the degrees of gray comparison and the kinds of measuring methods. The relationships between the fractal dimensions of broken surfaces and porcelain bend strengths are that they are in positive correlation on the low multiples and in negative correlation on the high multiples.

  8. Study on corrosion resistance of the BTESPT silane cooperating with rare earth cerium on the surface of aluminum-tube

    Institute of Scientific and Technical Information of China (English)

    肖围; 满瑞林; 缪畅; 彭天兰

    2010-01-01

    Bis-3-(triethoxysilyl)propyltetrasulfide(BTESPT) silane-rare earth cerium composite coatings on aluminum-tube were prepared at 60 °C by immersion method.The performance of composite coatings to protect the aluminum-tube against corrosion was investigated with potentiodynamic polarization curves,electrochemical impedance spectroscopy(EIS),and salt spray test(SST).The results of potentiodynamic polarization curves and EIS indicated that the self-corrosion current decreased by two orders of magnitude and the i...

  9. ANALYSIS OF SURFACE DEFECTS OF ALUMINUM AND ITS ALLOYS WITH A SCANNING KELVIN PROBE

    Directory of Open Access Journals (Sweden)

    A. K. Tyavlovsky

    2017-01-01

    Full Text Available Currently, the use of probe electrometry in non-destructive testing is constrained by the complexity of measurement results interpretation. An output signal of electrometric probe depends on a number of physical and chemical parameters of surface including chemical composition variations, stresses, dislocations, crystallographic orientation of a surface, etc. The study aims to the use of probe electrometry methods for nondestructive testing and analysis of precision metal surfaces’ defects after different treatment or processing.Control of surface defects of aluminum and its alloys was performed with a scanning Kelvin probe technique. The results of scanning were plotted in a form of contact potential difference (CPD distribution map. Additionally, a histogram of CPD values distribution and statistical characteristics including the expectation of CPD mean value and histogram half-width were calculated either for the whole distribution or for each individual mode in a case of multimodal distribution.The spatial CPD distribution of A99 aluminum and AMG-2 alloy surfaces after electrochemical polishing and diamond finishing was studied. An additional study was held for AMG-2 surface after the formation of 30 microns thick specific nanostructured alumina oxide surface layer. Higher quality surfaces have characterized as more homogeneous distribution of the physical properties (at half-width distribution histogram. Surfaces with higher mechanical strength and overall better mechanical properties found to have lower CPD values that correspond to higher electron work function and surface energy. The presence of the second mode in the CPD distribution histogram indicates the significant proportion of defect areas on the sample surface.Analysis of visualized CPD distribution maps using defined criteria allows detecting and characterizing such defects as residual stress areas, areas with reduced microhardness, surface contamination spots, corrosion

  10. The study of corrosion behavior of laser induced surface improvement (LISI) on steel and aluminum substrates

    Energy Technology Data Exchange (ETDEWEB)

    Lindsey, N.; Vasanth, K.L.

    1999-07-01

    Laser Induced Surface Improvement (LISI) is a new process developed by University of Tennessee Space Institute (UTSI) which employs lasers to melt precursor coatings and portions of the substrate to form a durable corrosion resistant surface. The LISI surface can be tailored to yield a composition that provides minimum impact to the base substrate material while giving good corrosion characteristics. The LISI surface treatment of tungsten carbide was applied on 7075 and 6061 aluminum alloys. The LISI treatment uses a chromium/nickel mixture and a stainless steel type mixture (pseudo stainless steel of 18 wt% chromium, 8 wt% nickel and a trace amount of manganese and silicon) on steel alloy 1010. The corrosion characteristics of these samples were determined in 3.5 wt% NaCl aqueous solution using linear polarization resistance technique. Potentiodynamic scans were run to determine the corrosion rates and optical microscopy was used to examine pitting characteristics of the different surface coatings. The effectiveness of the LISI modified surfaces to protect both steel and aluminum substrates is discussed.

  11. Characterization of Al{sub 2}O{sub 3} ceramic coatings on 6063 aluminum alloy prepared in borate electrolytes by micro-arc oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Li, H.X. [MOE Key Laboratory of Mechanical Manufacture and Automation, Zhejiang University of Technology, No. 6, Zhaohui District, Hangzhou 310014 (China); Rudnev, V.S. [Institute of Chemistry FEB RAS, Pr. 100 let Vladivostok, Vladivostok 690022 (Russian Federation); Zheng, X.H. [MOE Key Laboratory of Mechanical Manufacture and Automation, Zhejiang University of Technology, No. 6, Zhaohui District, Hangzhou 310014 (China); Yarovaya, T.P. [Institute of Chemistry FEB RAS, Pr. 100 let Vladivostok, Vladivostok 690022 (Russian Federation); Song, R.G. [MOE Key Laboratory of Mechanical Manufacture and Automation, Zhejiang University of Technology, No. 6, Zhaohui District, Hangzhou 310014 (China)], E-mail: songrg@zjut.edu.cn

    2008-08-25

    Al{sub 2}O{sub 3} ceramic coatings were directly prepared on 6063 aluminum alloy in borate electrolytes by micro-arc oxidation technique. The microstructure, phase composition, elemental distribution, and micro-hardness of Al{sub 2}O{sub 3} ceramic coatings were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and micro-hardness test. The fabricated samples were almost composed of {alpha}-Al{sub 2}O{sub 3} and {gamma}-Al{sub 2}O{sub 3}, also there existed pores and cracks on the surface of the coatings. Micro-hardness test shows that the prepared coatings are of high hardness, which can satisfy the requirements for the mechanical application.

  12. High-speed collision of copper nanoparticle with aluminum surface: Molecular dynamics simulation

    Science.gov (United States)

    Pogorelko, Victor V.; Mayer, Alexander E.; Krasnikov, Vasiliy S.

    2016-12-01

    We investigate the effect of the high-speed collision of copper nanoparticles with aluminum surface by means of molecular dynamic simulations. Studied diameter of nanoparticles is varied within the range 7.2-22 nm and the velocity of impact is equal to 500 or 1000 m/s. Dislocation analysis shows that a large quantity of dislocations is formed within the impact area. Overall length of dislocations is determined, first of all, by the impact velocity and by the size of incident copper nanoparticle, in other words, by the kinetic energy of the nanoparticle. Dislocations occupy the total volume of the impacted aluminum single crystal layer (40.5 nm in thickness) in the form of intertwined structure in the case of large kinetic energy of the incident nanoparticle. Decrease in the initial kinetic energy or increase in the layer thickness lead to restriction of the penetration depth of the dislocation net; formation of separate dislocation loops is observed in this case. Increase in the initial system temperature slightly raises the dislocation density inside the bombarded layer and considerably decreases the dislocation density inside the nanoparticle. The temperature increase also leads to a deeper penetration of the copper atoms inside the aluminum. Additional molecular dynamic simulations show that the deposited particles demonstrate a very good adhesion even in the case of the considered relatively large nanoparticles. Medium energy of the nanoparticles corresponding to velocity of about 500 m/s and elevated temperature of the system about 700-900 K are optimal parameters for production of high-quality layers of copper on the aluminum surface. These conditions provide both a good adhesion and a less degree of the plastic deformation. At the same time, higher impact velocities can be used for combined treatment consisting of both the plastic deformation and the coating.

  13. A study on the surface shape and roughness of aluminum alloy for heat exchanger using ball end milling

    Science.gov (United States)

    Lee, E.; Kim, Y.; jeong, H.; Chung, H.

    2015-09-01

    Aluminum alloy is a material with a high strength-weight ratio and excellent thermal conductivity. It neither readily corrodes nor quickly weakens at low temperatures, but can be easily recycled. Because of these features, aluminum heat exchangers are widely used in aluminum alloy. In addition, the aluminum alloy used in other areas is expected to gradually increase. As a result, researchers have been continuously studying the cutting patterns of aluminium alloy. However, such studies are fewer than those on the cutting patterns of ordinary steel. Moreover, the research on ball end milling with aluminium alloys has not received much attention. Therefore, in this study, an attempt was made to find the optimal cutting pattern among the seven cutting patterns for the machining of the commonly used aluminum alloy using ball end milling for a heat exchanger. The optimal pattern was found by comparing the different shapes and surface roughness values produced by the seven patterns.

  14. Investigation of Surface Roughness in High-Speed Milling of Aeronautical Aluminum Alloy

    Institute of Scientific and Technical Information of China (English)

    PAN Yong-zhi; AI Xing; ZHAO Jun; WAN Yi

    2008-01-01

    An approach is presented to optimize the surface roughness in high-speed finish milling of 7050-T7451 aeronautical aluminum alloy. In view of this, the multi-linear regression model for surface roughness has been developed in terms of slenderness ratio, cutting speed, radial depth-of-cut and feed per tooth by means of orthogonal experimental design. Variance analyses were applied to check the adequacy of the predictive model and the significances of the independent input parameters. Response contours of surface roughness were generated by using response surface methodology (RSM). From these contours, it was possible to select an optimum combination of cutting parameters that improves machining efficiency without increasing the surface roughness.

  15. Surface topographic characterization for polyamide composite injection molds made of aluminum and copper alloys.

    Science.gov (United States)

    Pereira, A; Hernández, P; Martinez, J; Pérez, J A; Mathia, T G

    2014-01-01

    In order to ensure flexibility and rapid new product development, the mold industry made use of soft materials for cavity inserts in injection molds. However, materials of this kind are prone to wear. This article analyzes the topographic characterization of the surface and wear processes in injection molds cavities. Two materials have been used to produce the cavities: aluminum alloy EN AW‐6082 T4 and copper alloy Cu Zn39 Pb3. The surface topography was measured with the use of optical interferometry profiling technology; roughness and surface parameters were determined according to ISO 4287, ISO 25178, and EUR 15178N. In order to complete this research, an experimental part with different thicknesses and shapes was designed, and cavity inserts of aluminum and copper were made. Polyamide PA6, with 30% fiberglass reinforcement, was employed in the experimental procedure. Measurements of cavity mold surfaces were performed after 9,200 cycles on each mold and at different locations on the mold. The surface measurement was made with a white light vertical scanning interferometry, also known as coherence scanning interferometry (ISO DIS 25178‐604). The results are analyzed and differences between the two types of cavity inserts materials are discussed.

  16. Preparation of Highly Pure Vanadyl Sulfate from Sulfate Solutions Containing Impurities of Iron and Aluminum by Solvent Extraction Using EHEHPA

    Directory of Open Access Journals (Sweden)

    Dan Li

    2017-03-01

    Full Text Available The preparation of highly pure vanadyl sulfate from sulfate solutions containing impurities of iron and aluminumwas investigated by solvent extraction with 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (EHEHPA and tri-n-butyl phosphate (TBP as the phase modifier. The extraction and stripping conditions of vanadium (IV and its separation from iron and aluminum were optimized. Under the optimal extraction conditions, the extraction of vanadium (IV and iron were 68% and 53%, respectively, while only 2% aluminum was extracted in a single contact, suggesting good separation of vanadium (IV from aluminum. Sulfuric acid solution was used for the stripping. Nearly 100% vanadium (IV and 95% aluminum were stripped, while only 10% iron was stripped under the optimal stripping conditions in a single contact, suggesting good separation of vanadium (IV from iron. After five stages of extraction and stripping, highly pure vanadyl sulfate containing 76.5 g/L V (IV with the impurities of 12 mg/L Fe and 10 mg/L Al was obtained, which is suitable for the electrolyte of a vanadium redox flow battery. Organic solution was well regenerated after stripping by oxalic acid solution to remove the remaining iron. The mechanism of vanadium (IV extraction using EHEHPA was also discussed based on the Fourier transform infrared spectroscopy (FT-IR analysis.

  17. Near-Surface Microstructure on Twin-Roll Cast 8906 Aluminum Alloy

    Science.gov (United States)

    Wang, Junjie; Zhou, Xiaorong; Thompson, George E.; Hunter, John A.; Yuan, Yudie

    2015-06-01

    The microstructure of the near-surface region of twin-roll cast foil stock 8906 AlFeSi alloy has been investigated. It was revealed that a near-surface layer with microstructure differing from that of the underlying bulk alloy was generated due to severe surface shear strain during twin-roll casting. Scanning and transmission electron microscopy showed that the near-surface layer consists of nano-sized grains with diameters varying in the range of 50 to 600 nm. Energy dispersive X-ray spectroscopy revealed that grain boundaries within the near-surface layer were decorated by aluminum oxide particles and carbon-containing lubricant inclusions. Preferential precipitation of a high population density of cubic α-AlFeSi dispersoids, of 30 to 150 nm diameter, was observed within the near-surface layer. The near-surface layer was associated with shingles on the twin-roll cast alloy surface and the maximum layer thickness of approximately 6 µm was observed at the shingles. Other areas of the surface were either free of the near-surface layer or had a thinner near-surface layer.

  18. Preparation of Chromium Oxide Coatings on Aluminum Borate Whiskers by a Hydrothermal Deposition Process

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Aluminum borate whiskers (9Al2O32B2O3) can be used to reinforce aluminum alloys to produce light and strong composites. However, the adverse interfacial reactions between the whiskers and the aluminum alloys inhibit their practical uses; therefore, a protective coating is needed on whiskers. In this work, aluminum borate whiskers were coated with chromium-coating deposits in a hydrothermal solution containing CrCl3, Na2C4H4O6, NaPH2O2, and H3BO3. The presence of the impurity P in the hydrothermal deposits can be avoided by reducing the amount of NaPH2O2 in the coating solution. Thermodynamic analysis was used to discuss the behavior of ions in the coating process. The subsequent heating of the hydrothermal products in air at 800 ℃ yielded smooth Cr2O3 films with a thickness of 0.060.07 μm.

  19. Preparation and Characterization of Low-Dielectric Glass Composite with Aluminum Borate

    Science.gov (United States)

    Jean, Jau-Ho; Hwang, Shiang-Po

    1994-10-01

    The effect of aluminum borate ( Al18B4O33) on crystallization and thermal expansion of Pyrex borosilicate glass has been studied. X-ray diffraction (XRD) results show that with 40 vol% aluminum borate, the precipitation of cristobalite in the Pyrex borosilicate glass is completely inhibited. This result is further evidenced by the linear thermal expansion measurement in which, in contrast to the system without aluminum borate, the thermal expansion coefficient remains unchanged with sintering time and is close to that of silicon, 3×10-6 K-1. Moreover, the composite with 40 vol% aluminum borate has a dielectric constant of 5.2 and a dielectric loss of 0.8% at 1 MHz.

  20. Laser irradiation effects on thin aluminum plates subjected to surface flow

    Science.gov (United States)

    Jiang, Houman; Zhao, Guomin; Chen, Minsun; Peng, Xin

    2016-10-01

    The irradiation effects of LD laser on thin aluminum alloy plates are studied in experiments characterized by relatively large laser spot and the presence of 0.3Ma surface airflow. A high speed profilometer is used to record the profile change along a vertical line in the rear surface of the target, and the history of the displacement along the direction of thickness of the central point at the rear surface is obtained. The results are compared with those without airflow and those by C. D. Boley. We think that it is the temperature rise difference along the direction of thickness instead of the pressure difference caused by the airflow that makes the thin target bulge into the incoming beam, no matter whether the airflow is blown or not, and that only when the thin aluminum target is heated thus softened enough by the laser irradiation, can the aerodynamic force by the surface airflow cause non-ignorable localized plastic deformation and result a burn-through without melting in the target. However, though the target isn't softened enough in terms of the pressure difference, it might have experienced notable deformation as it is heated from room temperature to several hundred degree centigrade.

  1. A molecular beacon biosensor based on the nanostructured aluminum oxide surface.

    Science.gov (United States)

    Che, Xiangchen; He, Yuan; Yin, Haocheng; Que, Long

    2015-10-15

    A new class of molecular beacon biosensors based on the nanostructured aluminum oxide or anodic aluminum oxide (AAO) surface is reported. In this type of sensor, the AAO surface is used to enhance the fluorescent signals of the fluorophore-labeled hairpin DNA. When a target DNA with a complementary sequence to that of the hairpin DNA is applied on the sensor, the fluorophores are forced to move away from the AAO surface due to the hybridization between the hairpin DNA and the target DNA, resulting in the significant decrease of the fluorescent signals. The observed signal reduction is sufficient to achieve a demonstrated detection limit of 10nM, which could be further improved by optimizing the AAO surface. The control experiments have also demonstrated that the bioassay used in the experiments has excellent specificity and selectivity, indicating the great promise of this type of sensor for diagnostic applications. Since the arrayed AAO micropatterns can be fabricated on a single chip in a cost-effective manner, the arrayed sensors could provide an ideal technical platform for studying fundamental biological process and monitoring disease biomarkers.

  2. Laser surface infiltration of tungsten-carbide in steel and aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Dahotre, N.B.; Mukherjee, K. (Michigan State Univ., East Lansing (USA))

    It has been demonstrated that surface modification in metals and alloys can be achieved by laser melting in conjunction with injection of particulate alloying elements in the heated zone. In our current experiments the authors have successfully implanted tungsten-carbide particles on the surface of several grades of carbon-steels as well as on the surface of a structural aluminum alloy. In both cases a significant increase in microhardness has been detected. Hardness profile from the interaction zone to the heat affected zone (HAZ) has been determined. The microstructural features of both the implanted zone and HAZ also have been determined. Effect of laser input energy, nature of tungsten-carbide particle size, size distribution and method of powder injection on the hardness profile have been investigated. Some preliminary examination of surface wear of such implanted material is also conducted. These results are discussed in detail.

  3. Retardation of surface corrosion of biodegradable magnesium-based materials by aluminum ion implantation

    Science.gov (United States)

    Wu, Guosong; Xu, Ruizhen; Feng, Kai; Wu, Shuilin; Wu, Zhengwei; Sun, Guangyong; Zheng, Gang; Li, Guangyao; Chu, Paul K.

    2012-07-01

    Aluminum ion implantation is employed to modify pure Mg as well as AZ31 and AZ91 magnesium alloys and their surface degradation behavior in simulated body fluids is studied. Polarization tests performed in conjunction with scanning electron microscopy (SEM) reveal that the surface corrosion resistance after Al ion implantation is improved appreciably. This enhancement can be attributed to the formation of a gradient surface structure with a gradual transition from an Al-rich oxide layer to Al-rich metal layer. Compared to the high Al-content magnesium alloy (AZ91), a larger reduction in the degradation rate is achieved from pure magnesium and AZ31. Our results reveal that the surface corrosion resistance of Mg alloys with no or low Al content can be improved by Al ion implantation.

  4. Assessment of airborne nanoparticles present in industry of aluminum surface treatments.

    Science.gov (United States)

    Santos, R J; Vieira, M T

    2017-03-01

    Conventional industrial processes are emission sources of unintended nanoparticles which are potentially harmful for the environment and human health. The aim of this study is to assess airborne nanoparticle release from aluminum surface treatment processes in various workplaces. Two direct reading instruments, a scanning mobility particle sizer to measure size distribution and a nanoparticle surface area monitoring to measure the surface area of particles deposited in the human lung, were employed to perform area monitoring. The lacquering paint was the process which released the highest concentration of particles from 10-487 nm (7.06 × 10(6) particles/cm(3)). The lacquering baths process emitted particles of the largest average size (76.9 nm) and the largest surface area deposited in the human lung (167.4 µm(2)/cm(3)). Conversely, the anodizing bath process generated particles of the smallest average size (44.3 nm) and the lowest human lung-deposited surface area (1.2 µm(2)/cm(3)). The total number of particles and the surface area can only be fairly correlated for environments in which the surface area presented higher values. The transmission electron microscopy analysis confirmed the presence of aluminum oxide particles of different dimensions near the LB and AB areas and polymeric-based particles near the LP areas. The findings of this study indicated that lacquering and anodizing surface treatments are indeed responsible for the emission of airborne nanoparticles. It also highlights the importance of control strategies as a means of protecting workers' health and environment.

  5. Effect of cerium addition on microstructure and texture of aluminum foil for electrolytic capacitors

    Institute of Scientific and Technical Information of China (English)

    王海燕; 李文学; 任慧平; 黄丽颖; 王向阳

    2010-01-01

    Anode foil of aluminum electrolytic capacitor,which requires large surface area for high capacitance,were prepared by rolling,annealing and electrochemical etching.Effects of cerium addition on the capacitance of aluminum electrolytic capacitors were investigated.Microstructure of the aluminum foil surface was observed by optical microscopy(OM) and scanning electron microscopy(SEM).Electron back scattered diffraction(EBSD) was also employed to reveal texture evolvement of cold-rolled aluminum foil after ann...

  6. Sample preparation for SEM of plant surfaces

    Directory of Open Access Journals (Sweden)

    A.K. Pathan

    2010-01-01

    Full Text Available Plant tissues must be dehydrated for observation in most electron microscopes. Although a number of sample processing techniques have been developed for preserving plant tissues in their original form and structure, none of them are guaranteed artefact-free. The current paper reviews common scanning electron microscopy techniques and the sample preparation methods employed for visualisation of leaves under specific types of electron microscopes. Common artefacts introduced by specific techniques on different leaf types are discussed. Comparative examples are depicted from our lab using similar techniques; the pros and cons for specific techniques are discussed. New promising techniques and microscopes, which can alleviate some of the problems encountered in conventional methods of leaf sample processing and visualisation, are also discussed. It is concluded that the choice of technique for a specific leaf sample is dictated by the surface features that need to be preserved (such as trichomes, epidermal cells or wax microstructure, the resolution to be achieved, availability of the appropriate processing equipment and the technical capabilities of the available electron microscope.

  7. Fabrication of Sup erhydrophobic Surfaces on Aluminum Alloy Via Electro dep osition of Copp er Followed by Electro chemical Mo dification

    Institute of Scientific and Technical Information of China (English)

    Ying Huang; D. K. Sarkar∗; X-Grant Chen

    2011-01-01

    Superhydrophobic aluminum surfaces have been prepared by means of electrodeposition of copper on aluminum surfaces, followed by electrochemical modification using stearic acid organic molecules. Scanning electron microscopy (SEM) images show that the electrodeposited copper films follow“island growth mode”in the form of microdots and their number densities increase with the rise of the negative deposition potentials. At an electrodeposition potential of −0.2 V the number density of the copper microdots are found to be 4.5×104 cm−2 that are increased to 2.9×105 cm−2 at a potential of −0.8 V. Systematically, the distances between the microdots are found to be reduced from 26.6 µm to 11.03 µm with the increase of negative electrochemical potential from −0.2 V to −0.8 V. X-ray diffraction (XRD) analyses have confirmed the formation of copper stearate on the stearic acid modified copper films. The roughness of the stearic acid modified electrodeposited copper films is found to increase with the increase in the density of the copper microdots. A critical copper deposition potential of −0.6 V in conjunction with the stearic acid modification provides a surface roughness of 6.2 µm with a water contact angle of 157◦, resulting in superhydrophobic properties on the aluminum sub-strates.

  8. Magnetron sputtering of silver nanowires using anodic aluminum oxide template: a new active substrate of surface enhanced Raman scattering and an investigation of its enhanced mechanism.

    Science.gov (United States)

    Zhang, Lisheng; Zhang, Pengxiang; Fang, Yan

    2007-05-22

    A high quality anodic aluminum oxide (AAO) template with ordered apertures about 50-80 nm was fabricated by anodizing aluminum in electrolytes through a two-step method, and silver nanowires with diameters from 40 nm to 70 nm were prepared on this AAO template by magnetron sputtering. On the glass covered with silver nanowires, high quality surface enhanced Raman scattering (SERS) spectra of sudan II (C18H16N2O) with enhancement factors of 10(5) were obtained. And comparison of SERS spectra on silver nanowires with the SERS spectra of silver colloids indicates that main enhanced mode is lightning rod effect of nanorods on the Sudan II/silver nanowires system.

  9. Preparation of α-Al2O3 base ceramic coating on aluminum alloy via thermo-decomposition of diaspore

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The aim of this work is to describe the possibilities of preparing a corundum coating onaluminum alloy through in-situ chemical reaction at a relative low temperature. The transformationconditions of diaspore (β-AIOOH) to corundum (α-Al2O3 ) are studied using X-ray diffraction analy-sis. Temperature and heating time are two main factors influencing the transformation. Suitableheating parameters can lower the transformation temperature. On this basis, a new process isdeveloped to produce corundum ceramic coating on an aluminum alloy substrate. The phasecomposition and microstructure of the coating are studied using X-ray diffraction analysis andScanning Electron Microscopy. Abrasion properties of the coating are evaluated by ring-block tri-botester. The results show that it is feasible to obtain ceramic coatings on aluminum alloy sub-strates by means of thermo-decomposition of diaspore.

  10. The Role of Friction Stir Processing (FSP Parameters on TiC Reinforced Surface Al7075-T651 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Felipe García-Vázquez

    Full Text Available Abstract: Aluminum alloys are very promising for structural applications in aerospace, military and transportation industries due to their light weight, high strength-to-weight ratio and excellent resistance to corrosion. In comparison to unreinforced aluminum alloys, aluminum/aluminum alloy matrix composites reinforced with ceramic phases exhibit higher strength and hardness, improved tribological characteristics. A novel surface modifying technique, friction stir processing (FSP, has been developed for fabrication of surface composite with an improved performance. The effect of FSP parameters such as number of passes, direction of each pass, sealed or unsealed groove on microstructure was investigated. In this work, nano-particles of TiC (2% in weight were added to aluminum alloy AA7075-T651 to produce a functional surface. Fixed parameters for this AA7075 alloy were used; rotation speed of 1000 rpm, travel speed of 300 mm/min and pin penetration of 2.8 mm. Optical microscopy (OM, scanning electron microscopy (SEM and atomic force microscopy (AFM were employed to study the microstructure of the fabricated surface composites. The results indicated that the selected FSP parameters influenced the area of surface composite, distribution of TiC particles and micro-hardness of the surface composites. Finally, in order to evaluate rate wear the pin on disk test was carried out.

  11. Surface reaction mechanisms during ozone and oxygen plasma assisted atomic layer deposition of aluminum oxide.

    Science.gov (United States)

    Rai, Vikrant R; Vandalon, Vincent; Agarwal, Sumit

    2010-09-07

    We have elucidated the reaction mechanism and the role of the reactive intermediates in the atomic layer deposition (ALD) of aluminum oxide from trimethyl aluminum in conjunction with O(3) and an O(2) plasma. In situ attenuated total reflection Fourier transform infrared spectroscopy data show that both -OH groups and carbonates are formed on the surface during the oxidation cycle. These carbonates, once formed on the surface, are stable to prolonged O(3) exposure in the same cycle. However, in the case of plasma-assisted ALD, the carbonates decompose upon prolonged O(2) plasma exposure via a series reaction kinetics of the type, A (CH(3)) --> B (carbonates) --> C (Al(2)O(3)). The ratio of -OH groups to carbonates on the surface strongly depends on the oxidizing agent, and also the duration of the oxidation cycle in plasma-assisted ALD. However, in both O(3) and O(2) plasma cycles, carbonates are a small fraction of the total number of reactive sites compared to the hydroxyl groups.

  12. Characterization of an Effective Cleaning Procedure for Aluminum Alloys: Surface Enhanced Raman Spectroscopy and Zeta Potential Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Cherepy, N J; Shen, T H; Esposito, A P; Tillotson, T M

    2004-06-02

    We have developed a cleaning procedure for aluminum alloys for effective minimization of surface-adsorbed sub-micron particles and non-volatile residue. The procedure consists of a phosphoric acid etch followed by an alkaline detergent wash. To better understand the mechanism whereby this procedure reduces surface contaminants, we characterized the aluminum surface as a function of cleaning step using Surface Enhanced Raman Spectroscopy (SERS). SERS indicates that phosphoric acid etching re-establishes a surface oxide of different characteristics, including deposition of phosphate and increased hydration, while the subsequent alkaline detergent wash appears to remove the phosphate and modify the new surface oxide, possibly leading to a more compact surface oxide. We also studied the zeta potential of <5 micron pure aluminum and aluminum alloy 6061-T6 particles to determine how surface electrostatics may be affected during the cleaning process. The particles show a decrease in the magnitude of their zeta potential in the presence of detergent, and this effect is most pronounced for particles that have been etched with phosphoric acid. This reduction in magnitude of the surface attractive potential is in agreement with our observation that the phosphoric acid etch followed by detergent wash results in a decrease in surface-adsorbed sub-micron particulates.

  13. THE EFFECTS OF CUTTING METHODS OF SURFACE ROUGHNESS OF ALUMINUM POROUS MATERIALPRODUCED VIA VACUUM METHOD

    Directory of Open Access Journals (Sweden)

    Lütfiye DAHIL

    2015-04-01

    Full Text Available In this study, the surface roughness values of 3 aluminum porous materials, which were produced via vacuum method and have different porous structures, depending on the implemented cutting method after processing them were assessed comparatively. 3 different cutting methods have been implemented on each of samples, as Water Jet, Wire Erosion, and Band Saw. Setting the speed to 20 m/min, the methods were compared under same conditions. The smoothness measurement has been executed by taking the mean of 3 measurements in parallel with surface and 3 measurements in vertical to surface. By comparing the obtained results, it has been determined that the most advantageous method is the Wire Erosion method.

  14. A Three-Dimensional Enormous Surface Area Aluminum Microneedle Array with Nanoporous Structure

    Directory of Open Access Journals (Sweden)

    Po Chun Chen

    2013-01-01

    Full Text Available We proposed fabricating an aluminum microneedle array with a nanochannel structure on the surface by combining micromachining, electrolyte polishing, and anodization methods. The microneedle array provides a three-dimensional (3D structure that possesses several hundred times more surface area than a traditional nanochannel template. Therefore, the microneedle array can potentially be used in many technology applications. This 3D microneedle array device can not only be used for painless injection or extraction, but also for storage, highly sensitive detection, drug delivery, and microelectrodes. From the calculation we made, the microneedle array not only increases surface area, but also enlarges the capacity of the device. Therefore, the microneedle array can further be used on many detecting, storing, or drug delivering applications.

  15. Oxidation-Induced Surface Roughening of Aluminum Nanoparticles Formed in an Ablation Plume

    Science.gov (United States)

    Förster, Georg Daniel; Girault, Marie; Menneveux, Jérôme; Lavisse, Luc; Jouvard, Jean-Marie; Marco de Lucas, Maria del Carmen; Potin, Valérie; Ouf, François-Xavier; Kerkar, Moussa; Le Garrec, Jean-Luc; Carvou, Erwann; Carles, Sophie; Rabilloud, Franck; Calvo, Florent; Yu, Jin; Mitchell, James Brian

    2015-12-01

    Nanoparticles formed within an ablation plume produced by the impact of a nanosecond laser pulse on the surface of an aluminum target have been directly measured using small-angle x-ray scattering. The target was immersed in an oxygen-nitrogen gas mixture at atmospheric pressure with the O2/N2 ratio being precisely controlled. The results for an increasing oxygen content reveal remarkable effects on the morphology of the generated particles, which include a decrease in the particle volume but a marked increase in its surface ruggedness. Molecular dynamics simulations using a reactive potential and performed under similar conditions as the experiment reproduce the experimental trends and show in detail how the shape and surface structure of the nanoparticles evolve with increasing oxygen content. This good agreement between in situ observations in the plume and atomistic simulations emphasizes the key role of chemical reactivity together with thermodynamic conditions on the morphology of the particles thus produced.

  16. Image potential resonances of the aluminum (100) surface; Bildpotentialresonanzen der Aluminium-(100)-Oberflaeche

    Energy Technology Data Exchange (ETDEWEB)

    Winter, Matthias

    2011-07-08

    Image-potential resonances on the (100) surface of pure Aluminum are investigated experimentally and theoretically. The experiments are conducted both energy- and time-resolved using the method of two-photon photoemission spectroscopy. The main attention of the theoretical examination and extensive numerical calculations is devoted to the interaction between surface and bulk states. Image-potential resonances on Al(100) are a system in which a complete series of discrete Rydberg states strongly couples to a continuum of states. As a simple metal it also provides a good opportunity to test theoretical models of the structure of the potential at metal surfaces. This work represents the first high-resolution investigation of image-potential resonances with such strong resonance character. For the first time, it is demonstrated experimentally that isolated image-potential resonances exist on an Aluminum surface. On the (100) surface of Aluminum the second through fifth image-potential resonance are resolved and both, their energies and lifetimes are measured. The binding energies of the image-potential resonances form a Rydberg series of states {epsilon}{sub n}=-(0,85 eV)/((n+a){sup 2}). Within the accuracy of the measurement it is not necessary to introduce a quantum defect a (a=0.022{+-}0.035). Using angle-resolved two-photon photoemission spectroscopy the effective mass of electrons in the second image-potential resonance is measured to 1.01{+-}0.11 electron masses. The lifetimes of the resonances increase as {tau}{sub n} = (1.0{+-}0.2)fs.n{sup 3} starting from n=2. Calculations using the density matrix formalism show that the experimentally observed lifetimes can be explained well by electrons decaying into the bulk. The effect of resonance trapping leads to extended lifetimes in the process. Contrary to common theoretical models of image-potential states at metal surfaces the first image-potential resonance cannot be observed in two-photon photoemission on Al(100

  17. Thermal effects in equilibrium surface segregation in a copper/10-atomic-percent-aluminum alloy using Auger electron spectroscopy

    Science.gov (United States)

    Ferrante, J.

    1972-01-01

    Equilibrium surface segregation of aluminum in a copper-10-atomic-percent-aluminum single crystal alloy oriented in the /111/ direction was demonstrated by using Auger electron spectroscopy. This crystal was in the solid solution range of composition. Equilibrium surface segregation was verified by observing that the aluminum surface concentration varied reversibly with temperature in the range 550 to 850 K. These results were curve fitted to an expression for equilibrium grain boundary segregation and gave a retrieval energy of 5780 J/mole (1380 cal/mole) and a maximum frozen-in surface coverage three times the bulk layer concentration. Analyses concerning the relative merits of sputtering calibration and the effects of evaporation are also included.

  18. Luminescence Properties of Ce3 +-Doped Terbium Aluminum Garnet Phosphor Prepared with Use of Nanostructured Reagents

    Directory of Open Access Journals (Sweden)

    I.V. Berezovskaya

    2013-03-01

    Full Text Available The paper describes the synthesis of Ce3 +-doped terbium aluminum garnet (TAG phosphors with use of nanostructured oxides of aluminum and rare earths. Aluminum oxide nanoparticles were obtained by gaseous-disperse synthesis and characterized by X-ray diffraction, differential thermal analysis and scanning electron microscopy. It was shown that the Ce3 + ions in TAG exhibit the intense broad band emission with a maximum at about 563 nm and the quantum efficiency of luminescence of the Тb3(1 – xCe3xAl5O12 (х = 0.03 phosphor was found as high as 0.83.

  19. Preparing Al-Mg Substrate for Thermal Spraying: Evaluation of Surface State After Different Pretreatments

    Science.gov (United States)

    Lukauskaitė, R.; Valiulis, A. V.; Černašėjus, O.; Škamat, J.; Rębiś, J. A.

    2016-08-01

    The article deals with the pretreatment technique for preparing the surface of aluminum alloy EN AW 5754 before thermal spray. The surface after different pretreatments, including degreasing with acetone, chemical etching with acidic and alkali solutions, grit-blasting, cathodic cleaning, and some combinations of these techniques, has been studied. The investigation of pre-treated surfaces covered the topographical study (using scanning electron microscopy, atomic force microscopy, and 3D profilometry), the chemical analysis by x-ray photoelectron spectroscopy, the evaluation of surface wettability (sessile drop method), and the assessment of surface free energy. Compared with all the techniques used in present work, the cathodic cleaning and its combination with grit-blasting provide the most preferable chemistry of the surface. Due to the absence of hydroxides at the surface and, possible, due to the diffusion of magnesium to the surface of substrate, the surface wettability and the surface free energy have been significantly improved. No direct correlation between the surface topography and the surface wettability has been established.

  20. Preparation and Coagulation Behavior of a Novel Multiple Flocculant Based on Cationic Polymer, Hydroxy Aluminum, and Clay Minerals

    Directory of Open Access Journals (Sweden)

    Feng-shan Zhou

    2015-01-01

    Full Text Available Cationic polymer, hydroxy aluminum, and clay minerals are three flocculants with different action mechanisms and a more cost-efficient multiple flocculant can be prepared by compositing them through appropriate technology. All of attapulgite (ATP, clay minerals containing magnesium, aluminum, and silicate, are porous environmental mineral material with good absorbability and have found wide applications in industrial sewage treatment. With polyaluminum chloride (PAC, poly(dimethyl diallyl ammonium chloride (PDMDAAC, and attapulgite (ATP clay being the main raw materials, multiple flocculant CMHa (liquid with good storage stability was prepared and its optimized blending mass percent was PDMDAAC of 2%-3%, ATP of 4%–6%, and PAC of 20%–30%. The liquid poly(dimethyl diallyl ammonium chloride (PDMDAAC was firstly loaded on solid material in kneader and then mixed in certain proportion with PAC and ATP to prepare solid CMHa convenient for storage and transportation. The optimized mass ratio is PAC : ATP : PDMDAAC = 80 : 10 : 2.4. When this multiple flocculant was used to treat domestic sewage, coal washing sewage, dyeing wastewater, and papermaking wastewater, its equivalent dosage was just 50% of PAC, while overall production cost has been reduced to about 40%, viewing showing broad application prospect.

  1. Antibacterial activity of Nb–aluminum oxide prepared by the non-hydrolytic sol–gel route

    OpenAIRE

    Alfenas, C. dos S.; Ricci, G. P.; De Faria, E. H.; Saltarelli, M.; Lima, O. J. de; Rocha, Z. N. da; E. J. Nassar; Calefi,Paulo Sergio; Montanari, Lilian B.; Martins, Carlos H. Gomes; Katia J. Ciuffi

    2011-01-01

    Acesso restrito: Texto completo. p. 65-70. Brazil has been the largest producer of niobium (Nb2O5) since 1980, and this material is usually applied to reduce corrosion in alloys. In addition, it has recently been evaluated for use in other technological areas, such as adsorption and catalysis. This paper presents the results of the antibacterial activity of Nb–aluminum oxide, designated MAC–Nb5+, prepared by the non-hydrolytic sol–gel route. The resulting material MAC–Nb5+ was character...

  2. Preparation of new base-aluminum-chloride-loaded fiber as adsorbent for fast removal of arsenic(Ⅴ) from water

    Institute of Scientific and Technical Information of China (English)

    Ying Meng; Jin Nan Wang; Cheng Cheng; Xin Yang; Ai Min Li

    2012-01-01

    A new base-aluminum-chloride-loaded fiber [PET-AA-NN-Al2(OH)nCl6_n] was prepared with polyethylene glycol terephthalate (PET) as adsorbent for fast removal of arsenic (V) from water.This new fibrous adsorbent was characterized by using SEM and C NMR spectroscopy.Adsorption kinetic curve indicated that this new fibrous adsorbent could fast remove arsenic (V) from water,and adsorption isotherm also indicated that PET-AA-NN-Al2(OH)nCl6_n had high equilibrium adsorption capacity for arsenic (V).

  3. Preparation and Characterization of Amorphous Layer on Aluminum Alloy Formed by Plasma Electrolytic Deposition (PED)

    Institute of Scientific and Technical Information of China (English)

    GUANYong-jun; XIAYuan

    2004-01-01

    In this investigation, protective layers were formed on aluminum substrate by Plasma Electrolytic Deposition (PED) using sodium silicate solution. The relation between the thickness of the layer and process time were studied. XRD, SEM, EDS were used to study the layer's structure, composition and micrograph. The results show that the deposited layers are amorphous and contain mainly oxygen, silicon, and aluminum. The possible formation mechanism of amorphous[Al-Si-O] layer was proposed: During discharge periods, Al2O3 phase of the passive film and SiO32- near the substrate surface are sintered into xSiO2(1-x)Al2O3 and then transformed into amorphous [Al-Si-O] phase.

  4. New Method to Characterize Degradation of First Surface Aluminum Reflectors: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Sutter, F.; Heller, P.; Meyen, S.; Pitz-Paal, R.; Kennedy, C.; Fernandez-Garcia, A.; Schmucker, M.

    2010-10-01

    This paper reports the development of a new optical instrument capable of characterizing the aging process of enhanced first surface aluminum reflectors for concentrating solar power (CSP) application. Samples were exposed outdoors at different sites and in accelerated exposure tests. All samples exposed outdoors showed localized corrosion spots. Degradation originated from points of damage in the protective coating, but propagated underneath the protective coating. The degraded samples were analyzed with a microscope and with a newly designed space-resolved specular reflectometer (SR)2 that is capable of optically detecting and characterizing the corrosion spots. The device measures the specular reflectance at three acceptance angles and the wavelengths with spatial resolution using a digital camera's CMOS sensor. It can be used to measure the corrosion growth rate during outdoor and accelerated exposure tests. These results will allow a correlation between the degraded mirror surface and its specular reflectance.

  5. Al/sub 2/S/sub 3/ preparation and use in electrolysis process for aluminum production

    Science.gov (United States)

    Hsu, C.C.; Loutfy, R.O.; Yao, N.P.

    A continuous process for producing aluminum sulfide and for electrolyzing the aluminum sulfide to form metallic aluminum in which the aluminum sulfide is produced from aluminum oxide and COS or CS/sub 2/ in the presence of a chloride melt which also serves as the electrolysis bath. Circulation between the reactor and electrolysis cell is carried out to maintain the desired concentration of aluminum sulfide in the bath.

  6. Specification guidelines for surface preparation of concrete prior to repair

    OpenAIRE

    Courard, Luc; Bissonnette, Benoît; Garbacz, Andrzej

    2017-01-01

    The repair of concrete requests specific preparation operations needed for guaranteeing compatibility between substrate and new materials as well as the development of adhesion properties. These specification guidelines contain design and construction recommendations for surface preparation of concrete for repair and overlay. The paper summarizes current knowledge, best practices and results of the research concerning the surface preparation of concrete prior to application of repair/overlay ...

  7. Adsorption kinetics of organophosphonic acids on plasma-modified oxide-covered aluminum surfaces.

    Science.gov (United States)

    Giza, M; Thissen, P; Grundmeier, G

    2008-08-19

    Tailoring of oxide chemistry on aluminum by means of low-pressure water and argon plasma surface modification was performed to influence the kinetics of the self-assembly process of octadecylphosphonic acid monolayers. The plasma-induced surface chemistry was studied by in situ FTIR reflection-absorption spectroscopy (IRRAS). Ex situ IRRAS and X-ray photoelectron spectroscopy were applied for the analysis of the adsorbed self-assembled monolayers. The plasma-induced variation of the hydroxide to oxide ratio led to different adsorption kinetics of the phosphonic acid from dilute ethanol solutions as measured by means of a quartz crystal microbalance. Water plasma treatment caused a significant increase in the density of surface hydroxyl groups in comparison to that of the argon-plasma-treated surface. The hydroxyl-rich surface led to significantly accelerated adsorption kinetics of the phosphonic acid with a time of monolayer formation of less than 1 min. On the contrary, decreasing the surface hydroxyl density slowed the adsorption kinetics.

  8. Optimal conditions for the preparation of superhydrophobic surfaces on al substrates using a simple etching approach

    Science.gov (United States)

    Ruan, Min; Li, Wen; Wang, Baoshan; Luo, Qiang; Ma, Fumin; Yu, Zhanlong

    2012-07-01

    Many methods have been proposed to develop the fabrication techniques for superhydrophobic surfaces. However, such techniques are still at their infant stage and suffer many shortcomings. In this paper, the superhydrophobic surfaces on an Al substrate were prepared by a simple etching method. Effects of etching time, modifiers, and modification concentration and time were investigated, and optimal conditions for the best superhydrophobicity were studied. It was demonstrated that for etching the aluminum plate in Beck's dislocation, if the etching time was 15 s, modifier was Lauric acid-ethanol solution, and modification concentration and time was 5% and 1.5 h, respectively, the surface exhibited a water contact angle as high as 167.5° and a contact angle hysteresis as low as 2.3°.

  9. Formation Mechanism of Micropores on the Surface of Pure Aluminum Induced by High-Current Pulsed Electron Beam Irradiation

    Institute of Scientific and Technical Information of China (English)

    ZOU Yang; CAI Jie; WAN Ming-Zhen; LV Peng; GUAN Qing-Feng

    2011-01-01

    The mechanism of micropores formed on the surface of polycrystalline pure aluminum under high-current pulsed electron beam (HCPEB) irradiation is explained. It is discovered that dispersed micropores with sizes of 0.1-1μm on the irradiated surface of pure aluminum can be successfully fabricated after HCPEB irradiation. The dominant formation mechanism of the surface micropores should be attributed to the formation of supersaturation vacancies within the near surface during the HCPEB irradiation and the migration of vacancies along gra,in boundaries and/or dislocations towards the irradiated surface. It is expected that the HCPEB technique will become a new method for the rapid synthesis of surface porous materials.%The mechanism of micropores formed on the surface of polycrystalline pure aluminum under high-current pulsed electron beam (HCPEB) irradiation is explained.It is discovered that dispersed micropores with sizes of 0.1-1μm on the irradiated surface of pure aluminum can be successfully fabricated after HCPEB irradiation.The dominant formation mechanism of the surface micropores should be attributed to the formation of supersaturation vacancies within the near surface during the HCPEB irradiation and the migration of vacancies along grain boundaries and/or dislocations towards the irradiated surface.It is expected that the HCPEB technique will become a new method for the rapid synthesis of surface porous materials.High-current pulsed electron beams (HCPEBs)have attracted much attention in the field of material surface modification.[1-7] During the transient bombardment process a high energy (108-109 W·cm-2) is deposited only in a very thin layer (less than tens of micrometers) within a very short time (a few microseconds) and thereby causes ultrafast heating and cooling on the irradiated surface of materials.The dynamic stress fields induced in these processes can induce intense deformation on the material surface.

  10. 铝基超疏水表面的制备及其耐蚀性%Preparation and corrosion resistance of superhydrophobic film on aluminum substrate

    Institute of Scientific and Technical Information of China (English)

    李杨; 王立达; 刘贵昌

    2012-01-01

    对铝基进行恒电流阳极氧化后,采用正辛基三乙氧基硅烷化学改性,制得超疏水膜.采用接触角测试仪、扫描电镜、红外光谱仪、电化学工作站等,研究了所得超疏水膜的静态接触角、表面形貌、结构及耐蚀性.结果表明,经阳极氧化后,铝基构建了粗糙的微纳米结构,再硅烷化处理后,铝基表面的疏水性增强,静态接触角大于150°.超疏水膜使铝在质量分数为3.5%的NaCl溶液中的自腐蚀电位正移0.11 V,腐蚀电流密度降低4个数量级,有效地提高了铝的耐蚀性.%A superhydrophobic film was prepared on aluminum substrate by anodic oxidation under constant current followed by chemical modification using n-octyltriethoxysilane. The static contact angle, surface morphology, structure, and corrosion resistance of the superhydrophobic film were studied using contact angle meter, scanning electron microscope, infrared spectroscope, and electrochemical workstation, respectively. The results showed that micro/nanostructures are formed on aluminum substrate by anodic oxidation. The hydrophobicity of the aluminum surface is enhanced through anodic oxidation followed by silanization, with a static contact angle being above 150°. The free corrosion potential of the superhydrophobic film is shifted positively by 0.11 V in 3.5wt% NaC1 solution, and the corrosion current density is decreased by 4 orders of magnitude, thus improving the corrosion resistance of aluminum effectively.

  11. Behavior of Aluminum Based Coagulants in Treatment of Surface Water–Assessment of Chemical and Microbiological Properties of Treated Water

    Directory of Open Access Journals (Sweden)

    Spînu (Gologan Daniela

    2014-03-01

    Full Text Available Pre-polymerized inorganic aluminum coagulants have high efficiency in reducing turbidity, total, dissolved, biodegradable organic carbon and microbiological content of surface waters used for drinking, while obtaining low concentrations of residual aluminum after the coagulation phase. Correlation between turbidity raw water and coagulant dose is logarithmic being influenced by temperature and organic content of surface waters. The coagulant’s effect on the organic content of the raw water is closely related to the microbiological concentration and can thus determine the mathematical correlations between the two types of parameters after the coagulation-flocculation stage that can be used to assess the water biostability coagulant action.

  12. Preparation of superhydrophobic surfaces on cotton textiles

    Directory of Open Access Journals (Sweden)

    Chao-Hua Xue et al

    2008-01-01

    Full Text Available Superhydrophobic surfaces were fabricated by the complex coating of silica nanoparticles with functional groups onto cotton textiles to generate a dual-size surface roughness, followed by hydrophobization with stearic acid, 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane or their combination. The wettability and morphology of the as-fabricated surfaces were investigated by contact angle measurement and scanning electron microscopy. Characterizations by transmission electron microscopy, Fourier transformation infrared spectroscopy, and thermal gravimetric analysis were also conducted.

  13. Superamphiphobic Surfaces Prepared by Coating Multifunctional Nanofluids.

    Science.gov (United States)

    Esmaeilzadeh, Pouriya; Sadeghi, Mohammad Taghi; Bahramian, Alireza; Fakhroueian, Zahra; Zarbakhsh, Ali

    2016-11-23

    Construction of surfaces with the capability of repelling both water and oil is a challenging issue. We report the superamphiphobic properties of mineral surfaces coated with nanofluids based on synthesized Co-doped and Ce-doped Barium Strontium Titanate (CoBST and CeBST) nanoparticles and fluorochemicals of trichloro(1H,1H,2H,2H-perfluorooctyl)silane (PFOS) and polytetrafluoroethylene (PTFE). Coating surfaces with these nanofluids provides both oil (with surface tensions as low as 23 mN/m) and water repellency. Liquids with high surface tension (such as water and ethylene glycol) roll off the coated surface without tilting. A water drop released from 8 mm above the coated surface undergoes first a lateral displacement from its trajectory and shape deformation, striking the surface after 23 ms, bouncing and rolling off freely. These multifunctional coating nanofluids impart properties of self-cleaning. Applications include coating surfaces where cleanliness is paramount such as in hospitals and domestic environments as well as the maintenance of building facades and protection of public monuments from weathering. These superamphiphobic-doped nanofluids have thermal stability up to 180 °C; novel industrial applications include within fracking and the elimination of condensate blockage in gas reservoirs.

  14. Preparation and Properties of Pillared Montmorillonite by Polyhydroxyl-aluminum-manganese Cations

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Al-Mn-pillared montmorillonite(AMPM) was prepared by using the artificial Na-montmorillonite from the Qingfengshan bentonite mine as starting materials mixed with Al-Mn pillaring solutions at different Al/Mn molar ratios(R).The basal spacing and specific surface area of the materials were increased significantly compared with untreated clays.When R=0.5, the d(001) value and specific surface area of pillared montmorillonite were 1.8987 nm and 146.01 m2 g-1,respectively.The thermal stability was determined using calcined tests,X-ray diffraction(XRD) analysis, thermal gravimetry and differential thermal analysis(TG-DTA).The materials formed at initial R=0.5 exhibited a high stability,the basal interlayer spacing was stabilized at 1.7859 nm after calcined for 2 h at 300℃.The adsorption behavior of the materials was studied by adsorption experiments.The results show the AMPM and calcined Al-Mn-pillared montmorillonite(CAMPM) exhibit a strong capacity of adsorbing the Zn(II) in aqueous solution at pH 10.0.

  15. Ion channel mimetic membranes and silica nanotubes prepared from porous aluminum oxide templates

    Science.gov (United States)

    Mitchell, David Tanner

    Chapter 1 provides background information on the template synthesis of nanomaterials. The template synthesis method is examined with special attention to the use of membranes containing monodisperse cylindrical pores as templates. Several examples of the utility of template-synthesized nanomaterials are given. The production of one type of template membrane, nanopore alumina, is reviewed. Reviews of sol-gel and silane chemistry are also provided. In Chapter 2, a sol-gel template synthesis process is used to produce silica nanotubes within the pores of alumina templates. The nanotubes can be modified using a variety of chemistries, typically via a silanization process. Because the nanotubes are formed in a template, the interior and exterior surface can be modified independently. Modified nanotubes can be used for drug detoxification or as extractants for the removal of metal ions. The nanotube surface can also be biotinylated, which causes binding to avidinated surfaces. Composite microtubes of silica and various polymers are also prepared. Additionally, Au nanowires are shown to assemble with colloidal Au particles using dithiols as linkers. Chapter 3 describes the attachment of proteins onto template-synthesized silica nanotubes. The proteins are covalently linked via an aldehyde silane bridge that binds to pendant primary amino moieties on the protein. Protein-modified nanotubes function as highly specific extractants. Avidin-modified nanotubes extract biotin-coated Au nanoparticles from solution with high extraction efficiency. Immunoprotein-modified nanotubes extract the corresponding antibody from solution with high specificity. Antibody-modified nanotubes extract one enantiomer from a racemic mix. Enzymes, including drug detoxification enzymes, were also attached to the nanotubes and were shown to retain their catalytic activity. Immunoproteins on the outside of nanotubes can be used to direct nanotube binding, creating specific labeling agents. Chapter 4

  16. The Effects of Burnishing and Conventional Finishing Processes on Surface Roughness and Roundness of the Al 6061 Aluminum Parts

    Directory of Open Access Journals (Sweden)

    Adnan AKKURT

    2009-03-01

    Full Text Available Burnishing is used increasingly as a finishing operation which gives additional advantages such as increased hardness and optimum surface roughness and becoming more popular in satisfying the increasing demands of machine component performance. It is very difficult getting rounded surfaces which are desired where hole machining process (turning, honing, reaming and burnishing. In this study, surface characterizations of getting surface with burnishing and other machining process was evaluated. Especially, inner surface of hole was examined and machining process compared. In the present work, Al 6061 aluminum alloy is selected as work piece material. The experimental results showed that burnishing process must be used where roundness is important. In addition, advantage of burnishing process for Al 6061 aluminum alloy material come out when comparing hardness of hole surface.

  17. Processing and mechanical properties of 2024 aluminum matrix composites containing Tungsten and Tantalum prepared by PM

    Institute of Scientific and Technical Information of China (English)

    LIAN Youyun; YANG Zhimin; YANG Jian; MAO Changhui

    2006-01-01

    The 2024 Al composites containing W, Ta were fabricated by powder metallurgy for their potential use as shielding material.W, Ta powders and gas-atomized 2024 Al aluminum powders were mixed by a ball mixer.The mixtures were consolidated by cold isostatic pressing (CIP) and then hot-extruded into full-density bars.The extruded bars were heat treated in T6 conditions.The microstructure and its relationship with the mechanical properties were investigated by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD).The results show that the particles of nonuniform size and irregular shape randomly disperse in the 2024 aluminum alloy matrix.The tensile tests show that an increase of tensile strength and decrease of elongation to failure of the heat treated composites compared with the extruded composites.

  18. Fracture characteristics of structural aerospace alloys containing deep surface flaws. [aluminum-titanium alloys

    Science.gov (United States)

    Masters, J. N.; Bixler, W. D.; Finger, R. W.

    1973-01-01

    Conditions controlling the growth and fracture of deep surface flaws in aerospace alloys were investigated. Static fracture tests were performed on 7075-T651 and 2219-T87 aluminum, and 6Ai-4V STA titanium . Cyclic flaw growth tests were performed on the two latter alloys, and sustain load tests were performed on the titanium alloy. Both the cyclic and the sustain load tests were performed with and without a prior proof overload cycle to investigate possible growth retardation effects. Variables included in all test series were thickness, flaw depth-to-thickness ratio, and flaw shape. Results were analyzed and compared with previously developed data to determine the limits of applicability of available modified linear elastic fracture solutions.

  19. Laser Peening on Aluminum Alloy 7049 Using Black Paint Surface Coating

    Directory of Open Access Journals (Sweden)

    Alalkawi H. J. M.

    2015-09-01

    Full Text Available Black paint laser peening (bPLP technique is currently applied for many engineering materials , especially for aluminum alloys due to high improvement in fatigue life and strength . Constant and variable bending fatigue tests have been performed at RT and stress ratio R= -1 . The results of the present work observed that the significance of the surface work hardening which generated high negative residual stresses in bPLP specimens .The fatigue life improvement factor (FLIF for bPLP constant fatigue behavior was from 2.543 to 3.3 compared to untreated fatigue and the increase in fatigue strength at 107 cycle was 21% . The bPLP cumulative fatigue life behavior was improved by 1.786 at L-H and 1.55 at H-L due to black paint coating .

  20. Laser assembly nanostructured Al2O3/TiO2 coating on cast aluminum surface

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guang-jun; DAI Jian-qiang; WANG Hui-ping; YAN Min-jie; XI Wen-long; ZOU Chang-gu; GE Da-fang

    2004-01-01

    CO2 laser quick assembly technology is adopted on the surface of cast aluminum ZL104 to form a dense ceramic coating containing a great deal of nanometer Al2O3/TiO2 particles which eliminate cracks and porosities.The major phases of the coating are α-Al2O3 andβ-TiO2. The micro-hardness distribution of the coating is 1 813,1 504, 1 485 and 1 232 (HV0.05). The bonding strength of the coating LC1 is 11.4 N, which is 7.26 times higher than that of the conventional hot-spraying Al2O3/TiO2 coating. It has been proved by analysis that the bonding strength is achieved because of the effects of both super-quick laser consolidation and the nanometer effect of nanometer ceramic material.

  1. Ultrafast laser induced periodic sub-wavelength aluminum surface structures and nanoparticles in air and liquids

    Energy Technology Data Exchange (ETDEWEB)

    Kuladeep, Rajamudili; Dar, Mudasir H.; Rao, D. Narayana, E-mail: dnrsp@uohyd.ac.in, E-mail: dnr-laserlab@yahoo.com [School of Physics, University of Hyderabad, Hyderabad 500046 (India); Deepak, K. L. N. [Department of Physics and Center for Research in Photonics, University of Ottawa, 150 Louis Pasteur, Ottawa K1N6N5, Ontario (Canada)

    2014-09-21

    In this communication, we demonstrate the generation of laser-induced periodic sub-wavelength surface structures (LIPSS) or ripples on a bulk aluminum (Al) and Al nanoparticles (NPs) by femtosecond (fs) laser direct writing technique. Laser irradiation was performed on Al surface at normal incidence in air and by immersing in ethanol (C₂H₅OH) and water (H₂O) using linearly polarized Ti:sapphire fs laser pulses of ~110 fs pulse duration and ~800 nm wavelength. Field emission scanning electron microscope is utilized for imaging surface morphology of laser written structures and it reveals that the spatial periodicity as well as the surface morphology of the LIPSS depends on the surrounding dielectric medium and also on the various laser irradiation parameters. The observed LIPSS have been classified as low spatial frequency LIPSS which are perpendicularly oriented to the laser polarization with a periodicity from 460 to 620 nm and high spatial frequency LIPSS which spectacles a periodicity less than 100 nm with the orientation parallel to the polarization of the incident laser beam. Fabricated colloidal solutions, which contain the Al NPs, were characterized by UV-Vis absorption spectroscopy and transmission electron microscopy (TEM). TEM results reveal the formation of internal cavities in Al NPs both in ethanol and water. Formation mechanism of LIPSS and cavities inside the nanoparticles are discussed in detail.

  2. Ultrafast laser induced periodic sub-wavelength aluminum surface structures and nanoparticles in air and liquids

    Science.gov (United States)

    Kuladeep, Rajamudili; Dar, Mudasir H.; Deepak, K. L. N.; Rao, D. Narayana

    2014-09-01

    In this communication, we demonstrate the generation of laser-induced periodic sub-wavelength surface structures (LIPSS) or ripples on a bulk aluminum (Al) and Al nanoparticles (NPs) by femtosecond (fs) laser direct writing technique. Laser irradiation was performed on Al surface at normal incidence in air and by immersing in ethanol (C2H5OH) and water (H2O) using linearly polarized Ti:sapphire fs laser pulses of ˜110 fs pulse duration and ˜800 nm wavelength. Field emission scanning electron microscope is utilized for imaging surface morphology of laser written structures and it reveals that the spatial periodicity as well as the surface morphology of the LIPSS depends on the surrounding dielectric medium and also on the various laser irradiation parameters. The observed LIPSS have been classified as low spatial frequency LIPSS which are perpendicularly oriented to the laser polarization with a periodicity from 460 to 620 nm and high spatial frequency LIPSS which spectacles a periodicity less than 100 nm with the orientation parallel to the polarization of the incident laser beam. Fabricated colloidal solutions, which contain the Al NPs, were characterized by UV-Vis absorption spectroscopy and transmission electron microscopy (TEM). TEM results reveal the formation of internal cavities in Al NPs both in ethanol and water. Formation mechanism of LIPSS and cavities inside the nanoparticles are discussed in detail.

  3. Sample preparation for SEM of plant surfaces

    OpenAIRE

    A.K. Pathan; Bond, J.; R.E. Gaskin

    2010-01-01

    Plant tissues must be dehydrated for observation in most electron microscopes. Although a number of sample processing techniques have been developed for preserving plant tissues in their original form and structure, none of them are guaranteed artefact-free. The current paper reviews common scanning electron microscopy techniques and the sample preparation methods employed for visualisation of leaves under specific types of electron microscopes. Common artefacts introduced by specific techniq...

  4. Microleakage in conservative cavities varying the preparation method and surface treatment

    Directory of Open Access Journals (Sweden)

    Juliana Abdallah Atoui

    2010-08-01

    Full Text Available OBJECTIVE: To assess microleakage in conservative class V cavities prepared with aluminum-oxide air abrasion or turbine and restored with self-etching or etch-and-rinse adhesive systems. Materials and Methods: Forty premolars were randomly assigned to 4 groups (I and II: air abrasion; III and IV: turbine and class V cavities were prepared on the buccal surfaces. Conditioning approaches were: groups I/III - 37% phosphoric acid; groups II/IV - self-priming etchant (Tyrian-SPE. Cavities were restored with One Step Plus/Filtek Z250. After finishing, specimens were thermocycled, immersed in 50% silver nitrate, and serially sectioned. Microleakage at the occlusal and cervical interfaces was measured in mm and calculated by a software. Data were subjected to ANOVA and Tukey's test (α=0.05. RESULTS: Marginal seal provided by air abrasion was similar to high-speed handpiece, except for group I. There was SIGNIFICANT difference between enamel and dentin/cementum margins for to group I and II: air abrasion. The etch-and-rinse adhesive system promoted a better marginal seal. At enamel and dentin/cementum margins, the highest microleakage values were found in cavities treated with the self-etching adhesive system. At dentin/cementum margins, high-speed handpiece preparations associated with etch-and-rinse system provided the least dye penetration. CONCLUSION: Marginal seal of cavities prepared with aluminum-oxide air abrasion was different from that of conventionally prepared cavities, and the etch-and-rinse system promoted higher marginal seal at both enamel and dentin margins.

  5. Influence of Surface Oxide Films on Elastic Behaviors of Straight Screw Dislocations Parallel to the Surface of Pure Aluminum

    Institute of Scientific and Technical Information of China (English)

    Weimin MAO; Dong LI; Yongning YU

    2007-01-01

    The image stress of straight screw dislocations parallel to the medium surface covered by thin heterogeneous films was analyzed and deduced, in order to calculate the image shear stress. The relationship between image stress and distance from the screw dislocation to the interface of pure aluminum and its oxide covering was calculated based on the analysis. It was shown quantitatively that a sign conversion of the image stress appears in the case of thin oxide covering, while dislocation would pile up near the interface because of the possible slips of the screw dislocations induced by the image stress, which might break down the very thin oxide covering. Further investigation on edge dislocations or other dislocation configurations need to be done.

  6. Laser surface modification treatment of aluminum bronze with B{sub 4}C

    Energy Technology Data Exchange (ETDEWEB)

    Yilbas, B.S., E-mail: bsyilbas@kfupm.edu.sa [Mechanical Engineering Department, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Matthews, A. [Mechanical Engineering Department, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Department of Materials Science and Engineering, Sheffield University (United Kingdom); Leyland, A. [Department of Materials Science and Engineering, Sheffield University (United Kingdom); Karatas, C. [Engineering Faculty, Hacettepe University (Turkey); Akhtar, S.S.; Abdul Aleem, B.J. [Mechanical Engineering Department, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Fine grains and dense layer were formed in the surface vicinity; in which Cu{sub 3}N compound was present. Black-Right-Pointing-Pointer Due to volume shrinkage of the dense layer, a few locally scattered voids were formed below the surface. Black-Right-Pointing-Pointer Formation of Cu{sub 3}N compound in the surface region enhanced microhardness at the surface. Black-Right-Pointing-Pointer In-plane residual stress was compressive at surface and it was on the order of -400 MPa. Black-Right-Pointing-Pointer Self-annealing effect of lately formed laser scanning tracks reduced residual stress at the surface. - Abstract: One technique to improve tribological properties of aluminum bronze surfaces is to introduce laser controlled melting at the surface in the presence of a composition-modifying film. In this work, a 40 {mu}m thick organic film, containing B{sub 4}C particles, was formed at the workpiece surface prior to laser treatment. The organic coating provides enhanced absorption of the incident laser radiation and distributes the B{sub 4}C particles uniformly across the surface. Morphological and microstructural changes in the laser treated layer were examined using scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. The microhardness of the laser treated layer was measured and the residual stress formed at the treated surface was evaluated by X-ray diffraction using the sin{sup 2} {psi} technique. It was found that the laser treated surface produced is relatively free from defects and asperities with a microhardness that is notably higher than that of the as-received bronze substrate. This hardening effect can be attributed to the development of a dense layer consisting of fine grains, partially dissolved B{sub 4}C particles, and formation of Cu{sub 3}N compounds. The residual compressive stress obtained from X-ray diffraction peak evaluation is of the order of -400 MPa.

  7. Porosity and surface roughness simulation of nickel-aluminum coating in plasma spray forming

    Institute of Scientific and Technical Information of China (English)

    ZENG Hao-ping; FANG Jian-cheng; XU Wen-ji; ZHAO Zi-yu; WANG Li

    2006-01-01

    As the important evaluation parameters concerning the spray qualities, the porosity and surface roughness of the coatings obtained by thermal spray forming have great influence on their forming accuracy, mechanical properties and service lifetime. But it is difficult to predict or control the two parameters for such a highly nonlinear process. A two-dimensional simulation of coating porosity and surface roughness of nickel-aluminum alloy (Ni-5%Al) in plasma spray forming was presented, which was based on the multi-dimensional statistical behaviors of the droplets as well as the simplification and digitization of the typical splat cross sections. Further analysis involving the influence of the droplet diameters and the scanning velocities of the spray gun on the two parameters was conducted. The simulation and analysis results indicate that the porosity and surface roughness are more influenced by the droplet diameters, but less influenced by the spray gun velocities. The results will provide basis for the prediction or control of coating mechanical properties by depositing parameters.

  8. Preparation and characterization of superhydrophobic surfaces based on hexamethyldisilazane-modified nanoporous alumina

    Directory of Open Access Journals (Sweden)

    Sanli Deniz

    2011-01-01

    Full Text Available Abstract Superhydrophobic nanoporous anodic aluminum oxide (alumina surfaces were prepared using treatment with vapor-phase hexamethyldisilazane (HMDS. Nanoporous alumina substrates were first made using a two-step anodization process. Subsequently, a repeated modification procedure was employed for efficient incorporation of the terminal methyl groups of HMDS to the alumina surface. Morphology of the surfaces was characterized by scanning electron microscopy, showing hexagonally ordered circular nanopores with approximately 250 nm in diameter and 300 nm of interpore distances. Fourier transform infrared spectroscopy-attenuated total reflectance analysis showed the presence of chemically bound methyl groups on the HMDS-modified nanoporous alumina surfaces. Wetting properties of these surfaces were characterized by measurements of the water contact angle which was found to reach 153.2 ± 2°. The contact angle values on HMDS-modified nanoporous alumina surfaces were found to be significantly larger than the average water contact angle of 82.9 ± 3° on smooth thin film alumina surfaces that underwent the same HMDS modification steps. The difference between the two cases was explained by the Cassie-Baxter theory of rough surface wetting.

  9. {sup 26}Al-containing acidic and basic sodium aluminum phosphate preparation and use in studies of oral aluminum bioavailability from foods utilizing {sup 26}Al as an aluminum tracer

    Energy Technology Data Exchange (ETDEWEB)

    Yokel, Robert A. [College of Pharmacy, 511C Pharmacy Building 725 Rose Street, University of Kentucky Medical Center, Lexington, KY 40536-0082 (United States) and Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40536-0305 (United States)]. E-mail: ryokel@email.uky.edu; Urbas, Aaron A. [Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055 (United States); Lodder, Robert A. [College of Pharmacy, 511C Pharmacy Building 725 Rose Street, University of Kentucky Medical Center, Lexington, KY 40536-0082 (United States); Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055 (United States); Selegue, John P. [Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055 (United States); Florence, Rebecca L. [College of Pharmacy, 511C Pharmacy Building 725 Rose Street, University of Kentucky Medical Center, Lexington, KY 40536-0082 (United States)

    2005-04-01

    We synthesized {sup 26}Al-containing acidic and basic (alkaline) sodium aluminum phosphates (SALPs) which are FDA-approved leavening and emulsifying agents, respectively, and used them to determine the oral bioavailability of aluminum incorporated in selected foods. We selected applicable methods from published syntheses (patents) and scaled them down ({approx}3000- and 850-fold) to prepare {approx}300-400 mg of each SALP. The {sup 26}Al was incorporated at the beginning of the syntheses to maximize {sup 26}Al and {sup 27}Al equilibration and incorporate the {sup 26}Al in the naturally-occurring Al-containing chemical species of the products. Near infrared spectroscopy (NIR) and X-ray powder diffraction (XRD) were used to characterize the two SALP samples and some intermediate samples. Multi-elemental analysis (MEA) was used to determine Na, Al and P content. Commercial products were included for comparison. Satisfactory XRD analyses, near infrared spectra and MEA results confirmed that we synthesized acidic and basic SALP, as well as some of the syntheses intermediates. The {sup 26}Al-containing acidic and basic SALPs were incorporated into a biscuit material and a processed cheese, respectively. These were used in oral bioavailability studies conducted in rats in which the {sup 26}Al present in blood after its oral absorption was quantified by accelerator mass spectrometry. The results showed oral Al bioavailability from acidic SALP in biscuit was {approx}0.02% and from basic SALP in cheese {approx}0.05%, lower than our previous determination of Al bioavailability from drinking water, {approx}0.3%. Both food and water can appreciably contribute to the Al absorbed from typical human Al intake.

  10. 镁合金表面铝化及其合金涂层研究现状%Research Status of Aluminized and Aluminum Alloy Coating on Surface of Magnesium Alloy

    Institute of Scientific and Technical Information of China (English)

    陈刚; 章国伟; 马力; 张立君

    2012-01-01

    总结了国内外镁合金表面铝化及其合金涂层研究现状,分析了镁合金表面铝化及其涂层防护特点,介绍了渗铝法、磁控溅射法、冷喷涂和热喷涂法制备研究铝及其涂层的制备工艺及研究成果.%The international research on the protective characters of the aluminum coating and aluminum alloy on the surface of magnesium alloy was summarized. The progress of aluminized, magnetron sputtering, cold spraying and thermal spraying methods to prepare the aluminum coating and the research results were introduced.

  11. Preparation and thermal properties of form-stable palmitic acid/active aluminum oxide composites as phase change materials for latent heat storage

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Guiyin, E-mail: gyfang@nju.edu.cn [School of Physics, Nanjing University, Nanjing 210093 (China); Li, Hui [Department of Material Science and Engineering, Nanjing University, Nanjing 210093 (China); Cao, Lei; Shan, Feng [School of Physics, Nanjing University, Nanjing 210093 (China)

    2012-12-14

    Form-stable palmitic acid (PA)/active aluminum oxide composites as phase change materials were prepared by adsorbing liquid palmitic acid into active aluminum oxide. In the composites, the palmitic acid was used as latent heat storage materials, and the active aluminum oxide was used as supporting material. Fourier transformation infrared spectroscope (FT-IR), X-ray diffractometer (XRD) and scanning electronic microscope (SEM) were used to determine the chemical structure, crystalloid phase and microstructure of the composites, respectively. The thermal properties and thermal stability were investigated by a differential scanning calorimeter (DSC) and a thermogravimetry analyzer (TGA). The FT-IR analyses results indicated that there is no chemical interaction between the palmitic acid and active aluminum oxide. The SEM results showed that the palmitic acid was well adsorbed into porous network of the active aluminum oxide. The DSC results indicated that the composites melt at 60.25 Degree-Sign C with a latent heat of 84.48 kJ kg{sup -1} and solidify at 56.86 Degree-Sign C with a latent heat of 78.79 kJ kg{sup -1} when the mass ratio of the PA to active aluminum oxide is 0.9:1. Compared with that of the PA, the melting and solidifying time of the composites CPCM5 was reduced by 20.6% and 21.4% because of the increased heat transfer rate through EG addition. The TGA results showed that the active aluminum oxide can improve the thermal stability of the composites. -- Highlights: Black-Right-Pointing-Pointer Form-stable PA/active aluminum oxide composites as PCMs were prepared. Black-Right-Pointing-Pointer Chemical structure, crystalloid phase and microstructure of composites were determined. Black-Right-Pointing-Pointer Thermal properties and thermal stability of the composites were investigated. Black-Right-Pointing-Pointer Expanded graphite can improve thermal conductivity of the composites.

  12. Multi-scale cell/surface interaction on modified titanium aluminum vanadium surfaces

    Science.gov (United States)

    Chen, Jianbo

    This dissertation presents a series of experimental studies of the effects of multi-scale cell/surface interactions on modified Ti-6Al-4V surfaces. These include laser-grooved surfaces; porous structures and RGD-coated laser-grooved surfaces. A nano-second DPSS UV lasers with a Gaussian pulse energy profile was used to introduce the desired micro-groove geometries onto Ti-6Al-4V surfaces. This was done without inducing micro-cracks or significant changes in surface chemistry within the heat affected zones. The desired 8-12 mum groove depths and widths were achieved by the control of pulse frequency, scan speed, and the lens focal length that controls spot size. The interactions between human osteosarcoma (HOS) cells and laser-grooved Ti-6Al-4V surfaces were investigated after 48 hours of cell culture. The cell behavior, including cell spreading, alignment and adhesion, was elucidated using scanning electronic microscopy (SEM), immuno-fluorescence staining and enzymatic detachment. Contact guidance was shown to increase as grooved spacing decreased. For the range of micro-groove geometries studied, micro-grooves with groove spacings of 20 mum provided the best combination of cell orientation and adhesion. Short-term adhesion experiments (15 mins to 1 day) also revealed that there is a positive correlation between cell orientation and cell adhesion. Contact guidance on the micro-grooved surfaces is shown to be enhanced by nano- and micro-scale asperities that provide sites for the attachment of lamellopodia during cell locomotion and spreading. Contact guidance is also promoted by the geometrical confinement provided by laser grooves. An experimental study of initial cell spreading and ingrowth into Ti-6Al-4V porous structures was also carried out on porous structures with different pore sizes and geometries. A combination of SEM, the tetrazolium salt (MTT) colorimetric assay and enzymatic detachment were used to study cell spreading and adhesion. The extent of cell

  13. Preparation, Microstructure, and Mechanical Properties of Spinel-Corundum-Sialon Composite Materials from Waste Fly Ash and Aluminum Dross

    Directory of Open Access Journals (Sweden)

    Juntong Huang

    2014-01-01

    Full Text Available The solid wastes fly ash and aluminum dross were used to prepare the low cost, high added-value product spinel-corundum-Sialon with an in situ aluminothermic reduction-nitridation reaction. The effects of varying raw material components and heating temperatures on the phase compositions, microstructure, bulk density, apparent porosity, and bending strength of products were investigated. The presence of hazardous or impure elements in the products was also evaluated. The sintered materials mainly consisted of micro-/nanosized plate corundum, octahedral spinel, and hexagonal columnar β-Sialon. The bulk density and bending strength of product samples initially increased and then decreased as Al content increased. Product samples with an Al content exceeding 10 mass% that were sintered at 1450°C exhibited the highest bending strength (288 MPa, the lowest apparent porosity (1.24%, and extremely low linear shrinkage (0.67%. The main impurity present was Fe5Si3 with hazardous elements P, Cr, Mn, and Ni doping. This work could provide a new method to reduce environmental pollution and manufacture low cost high performance refractory materials using the abundant waste materials fly ash and aluminum dross.

  14. Effect of Aluminum Substrate Surface Modification on Wettability and Freezing Delay of Water Droplet at Subzero Temperatures

    DEFF Research Database (Denmark)

    Rahimi, Maral; Afshari, Alireza; Thormann, Esben

    2016-01-01

    In this study, we have investigated the freezing delay of a water droplet on precooled substrates of an aluminum alloy that is commonly used for heat-exchanger fins. The surfaces of the substrates were modified to obtain surfaces with different hydrophilicity/hydrophobicity and different surface...... hydrophobic substrates. We suggest that this is because this particular surface chemistry prevents ice formation at the interface of the substrate, prior to the deposition of the water droplet. On the basis of our results, we suggest that not only wettability and topography but also the concrete surface...

  15. Modeling the Effects of Tool Shoulder and Probe Profile Geometries on Friction Stirred Aluminum Welds Using Response Surface Methodology

    Institute of Scientific and Technical Information of China (English)

    H.K.Mohanty; M.M.Mahapatra; P.Kumar; P.Biswas; N.R.Mandal

    2012-01-01

    The present paper discusses the modeling of tool geometry effects on the friction stir aluminum welds using response surface methodology.The friction stir welding tools were designed with different shoulder and tool probe geometries based on a design matrix.The matrix for the tool designing was made for three types of tools,based on three types of probes,with three levels each for defining the shoulder surface type and probe profile geometries.Then,the effects of tool shoulder and probe geometries on friction stirred aluminum welds were experimentally investigated with respect to weld strength,weld cross section area,grain size of weld and grain size of thermo-mechanically affected zone.These effects were modeled using multiple and response surface regression analysis.The response surface regression modeling were found to be appropriate for defining the friction stir weldment characteristics.

  16. Preparation of semi-solid aluminum alloy slurry poured through a water-cooled serpentine channel

    Science.gov (United States)

    Chen, Zheng-Zhou; Mao, Wei-Min; Wu, Zong-Chuang

    2012-01-01

    A water-cooled serpentine channel pouring process was invented to produce semi-solid A356 aluminum alloy slurry for rheocasting, and the effects of pouring temperature and circulating cooling water flux on the microstructure of the slurry were investigated. The results show that at the pouring temperature of 640-680°C and the circulating cooling water flux of 0.9 m3/h, the semi-solid A356 aluminum alloy slurry with spherical primary α(Al) grains can be obtained, whose shape factors are between 0.78 and 0.86 and the grain diameter can reach 48-68 μm. When the pouring temperatures are at 660-680°C, only a very thin solidified shell remains inside the serpentine channel and can be removed easily. When the serpentine channel is cooled with circulating water, the microstructure of the semi-solid slurry can be improved, and the serpentine channel is quickly cooled to room temperature after the completion of one pouring. In terms of the productivity of the special equipment, the water-cooled serpentine channel is economical and efficient.

  17. Comparisons of computer-controlled chamber measurements for soil-skin adherence from aluminum and carpet surfaces.

    Science.gov (United States)

    Ferguson, Alesia; Bursac, Zoran; Coleman, Sheire; Johnson, Wayne

    2009-04-01

    A computer-controlled mechanical chamber was used to control the contact between carpet and aluminum sheet samples laden with soil, and human cadaver skin and cotton sheet samples for the measurement of mass soil transfer. The contact parameters of pressure (10-50 kPa) and time (10-50s) were varied for 768 experiments of mass soil transfer, where two soil types (play sand and lawn soil) and two soil particle sizes (soil mass transfer to cadaver skin was higher than mean transfer to cotton sheets for both carpet and aluminum transfers, and also generally higher pressure was associated with larger amounts of soil transfer for all contact scenarios. The mean soil adherence from carpet was 0.37+/-0.4 mg/cm(2), while the mean soil adherence from aluminum was 0.42+/-0.6 mg/cm(2). For aluminum, smaller soil particle size was associated with more transfer (p=0.0349), while for carpet, larger soil size was associated with more transfer (pSoil type was significant but only for aluminum surface, where sand was associated with higher adherence (psoils and dust present in indoor environments.

  18. The corrosion behaviour of the aluminum alloy 7075/SiCp metal matrix composite prepared by spray deposition

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Y.L.; Chen, Z.H.; Wu, H.L.; Wang, H.M. [College of Materials Science and Engineering, Hunan University, Changsha (China)

    2007-04-15

    Aluminum alloy 7075 and 7075/SiCp (MMC) were prepared by multi-layer spray deposition method and the corrosion behaviour of them were studied by electrochemical measurements to study the effect of the addition of silicon carbide on the corrosion behaviour of the MMC. The electrochemical noise result shows that the amplitude of the potential noise of the composite is lower than that of the spray deposited 7075 alloy. The potentiodynamic polarization curves results show that both the cathodic oxygen reduction current density and the anodic dissolution current density of the 7075/SiCp MMC are less than those of the 7075 alloy. Thus, the addition of SiC particles increases the corrosion resistance of the MMC. This may be due to that the microstructure of the spray deposited MMC is compact and SiC particles are nonmetallic material, the addition of it minimizes the real corrosion area of the alloy. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  19. Surface adsorption of organoarsenic roxarsone and arsanilic acid on iron and aluminum oxides.

    Science.gov (United States)

    Chen, Wan-Ru; Huang, Ching-Hua

    2012-08-15

    Aromatic organoarsenicals roxarsone (ROX) and p-arsanilic acid (ASA) are common feed additives for livestock and could be released into the environment via animal manure and agricultural runoff. To evaluate their environmental fate, the adsorption behavior of ROX and ASA was investigated with two common soil metal oxides, goethite (FeOOH) and aluminum oxide (Al(2)O(3)), under different reactant loading, water pH and competing ion conditions. ROX and ASA exhibit essentially identical adsorption characteristics. FeOOH and Al(2)O(3) exhibit similar adsorption trends for both organoarsenicals; however, the adsorption efficiency on the surface site basis was about three times lower for Al(2)O(3) than for FeOOH. The adsorption reaction is favorable at neutral and acidic pH. Phosphate and natural organic matter significantly interfere with aromatic arsenical adsorption on both metal oxides, whereas sulfate and nitrate do not. Pre-adsorbed aromatic arsenicals can be quickly but not completely displaced by phosphate, indicating that ion exchange is not the only mechanism governing the adsorption process. The adsorption envelope was successfully modeled by a diffuse double layer surface complexation model, identifying the critical role of di-anionic organoarsenic species in the adsorption. Results of this research can help predict and control the mobility of aromatic arsenicals in the environment.

  20. Solidification behavior and rheo-diecasting microstructure of A356 aluminum alloy prepared by self-inoculation method

    Directory of Open Access Journals (Sweden)

    Ming Li

    2017-01-01

    Full Text Available Semisolid slurry of A356 aluminum alloy was prepared by self-inoculation method, and the microstructure and solidification behavior during rheo-diecasting process were investigated. The results indicate that the semisolid slurry of A356 aluminum alloy can be prepared by self-inoculation method at 600 °C. Primary α-Al particles with fine and spherical morphologies are uniformly distributed when the isothermal holding time of slurry is 3 min. Liquid phase segregation occurs during rheo-diecasting process of semisolid slurry and the primary particles (α1 show obvious plastic deformation in the area of high stress and low cooling rate. A small amount of dendrites resulting from the relatively low temperature of the shot chamber at the initial stage of secondary solidification are fragmented as they pass through the in-gate during the mould filling process. The amount of dendrite fragments decreases with the increase of filling distance. During the solidification process of the remaining liquid, the nucleation rate of secondary particles (α2 increases with the increase of cooling rate, and the content of Si in secondary particles (α2 are larger than primary particles (α1. With the increase of cooling rate, the content of Si in secondary particles (α2 gradually increases. The morphologies of eutectic Si in different parts of die casting are noticeably different. The low cooling rate in the first filling positions leads to coarse eutectic structures, while the high cooling rate in the post filling positions promotes small and compact eutectic structures.

  1. Preparation of well-aligned carbon nanotubes/silicon nanowires core-sheath composite structure arrays in porous anodic aluminum oxide templates

    Institute of Scientific and Technical Information of China (English)

    李梦轲; 陆梅; 王成伟; 力虎林

    2002-01-01

    The well-aligned carbon nanotubes (CNTs) arrays with opened ends were prepared in ordered pores of anodic aluminum oxide (AAO) template by the chemical vapor deposition (CVD) method. After then, silicon nanowires (SiNWs) were deposited in the hollow cavities of CNTs. By using this method, CNTs/SiNWs core-sheath composite structure arrays were synthesized successfully. Growing structures and physical properties of the CNTs/SiNWs composite structure arrays were analyzed and researched by the scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction spectrum (XRD), respectively. The field emission (FE) behavior of the CNTs/SiNWs composite structure arrays was studied based on Fowler- Nordheim tunneling mechanism and current-voltage (I -V) curve. And the photoluminescence (PL) was also characterized. Significantly, the CNTs/SiNWs core-sheath composite structure nanowire fabricated by AAO template method is characteristic of a metal/semiconductor (M/S) behavior and can be utilized to synthesize nanoscale PN junction or Schottky diode device. This process also could be useful for the fabrication of SiNWs and other nanoscale core-sheath composite structure nanowires with chemically inert interfaces for nanoscale electronic and device applications where surface oxidation is undesirable. The diameters and lengths of nanoscale composite structure arrays can be dominated easily, and the experimental result shows that the curling and twisting structures are fewer than those prepared by other synthesized methods.

  2. Preparation and characterization of low-defect surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, T.O.

    1991-12-01

    Silver crystal surfaces with low defect densities were prepared electrochemically from aqueous solutions using capillary-growth techniques. These surfaces had low rates for the nucleation of new silver layers. The impedance of these inert silver/aqueous silver nitrate interfaces was used to determine silver adatom concentration and water dipole reorientation energetics.

  3. An easy and environmentally-friendly approach to superamphiphobicity of aluminum surfaces

    Science.gov (United States)

    Deng, R.; Hu, Y. M.; Wang, L.; Li, Zh. H.; Shen, T.; Zhu, Y.; Xiang, J. Zh.

    2017-04-01

    Superamphiphobic Al surfaces were achieved via an easy and environmentally-friendly approach. Aqueous mixed solution of 0.7 M CuSO4 and 1 M NaCl was used to etch polished Al surfaces to fabricate a rough morphology distributed with microscale step-like pits. The uniformly distributed nanoscale petals covered on the microscale pits were obtained by subsequent 96 °C hot deionized water bathing for 13 min. Thus, the hierarchical micro/nanometer scale roughness was formed which provided the structural basic of superamphiphobic Al surfaces. By 1H, 1H, 2H, 2H-Perfluorodecyl-triethoxysilane (PFDTS) derivatization, desirable superamphiphobic Al surfaces were achieved with the highest static contact angles of 162° for water, 156° for peanut oil, respectively. Meanwhile, the sliding angles were lower than 10° for both water and peanut oil droplets. The as-prepared Al surfaces were investigated by field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and optical contact angle measurements. The FE-SEM images of as-prepared Al surfaces showed a hierarchical micro/nanometer scale morphology. XPS analyses demonstrated the PFDTS derivitization on Al surfaces. The superamphiphobic Al surfaces presented good mechanical durability and chemical stability which have a wide range of applications in fields such as self-cleaning, anti-icing, anti-corrosion, oil transportation, energy harvesting, microfluidics, and so forth. The approach reported in this paper may easily realize the industrial production of superamphiphobic Al surfaces owing to the advantage of facile, low cost and environmentally-friendly.

  4. Tribological Behavior of A356/Al2O3 Surface Nanocomposite Prepared by Friction Stir Processing

    Science.gov (United States)

    Mazaheri, Y.; Karimzadeh, F.; Enayati, M. H.

    2014-04-01

    Surface A356 aluminum alloy matrix composites containing micro and nanosized Al2O3 are prepared by a new approach utilizing high-velocity oxy-fuel spraying and friction stir processing (FSP). Optical and scanning electron microscopy, microhardness, and wear tests were used to characterize the surface composites. Results indicated that, the presence of Al2O3 in matrix can improve the mechanical properties of specimens. The microhardness of surface composites containing micro and nanosized Al2O3 were 89.8 ± 2.6 HV and 109.7 ± 2.5 HV, respectively, which were higher than those for the as-received (79.6 ± 1.1 HV) and the FSPed A356-T6 with no alumina powder (66.8 ± 0.9 HV). Surface composites revealed low friction coefficients and wear rates, which were significantly lower than those obtained for substrate. The wear mass losses of the as-received, the FSPed, and surface micro and nanocomposite specimens after 500-m sliding distance were 50.5, 55.6, 31, and 17.2 mg, respectively. Scanning electron microscopy tests revealed different wear mechanisms on the surface of the wear test specimens.

  5. Preparation of Porous Alumina Film on Aluminum Substrate by Anodization in Oxalic Acid

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Self-ordering of the cell arrangement of the anodic porous alumina was prepared in oxalic acid solution at a constant potential of 40V and at a temperature of 20°C. The honeycomb structure made by one step anodization method and two step anodization method is different.Pores in the alumina film prepared by two step anodization method were more ordered than those by one step anodization method.

  6. Effect of preparation conditions on physicochemical, surface and catalytic properties of cobalt ferrite prepared by coprecipitation

    Energy Technology Data Exchange (ETDEWEB)

    El-Shobaky, G.A., E-mail: elshobaky@yahoo.co [Physical Chemistry Department, National Research Center, Dokki, Cairo (Egypt); Turky, A.M.; Mostafa, N.Y.; Mohamed, S.K. [Chemistry Department, Faculty of Science, Suez Canal University, Ismailia 41522 (Egypt)

    2010-03-18

    Cobalt ferrite nanoparticles were prepared via thermal treatment of cobalt-iron mixed hydroxides at 400-600 {sup o}C. The mixed hydroxides were coprecipitated from their nitrates solutions using NaOH as precipitating agent. The effects of pH and temperature of coprecipitation and calcination temperature on the physicochemical, surface and catalytic properties of the prepared ferrites were studied. The prepared systems were characterized using TG, DTG, DTA, chemical analysis, atomic absorption spectroscopy (AAS), X-ray diffraction (XRD), energy dispersive X-ray (EDX) as well as surface and texture properties based on nitrogen adsorption-desorption isotherms. The prepared cobalt ferrites were found to be mesoporous materials that have crystallite size ranges between 8 and 45 nm. The surface and catalytic properties of the produced ferrite phase were strongly dependent on coprecipitation conditions of the mixed hydroxides and on their calcination temperature.

  7. Single step method to fabricate durable superliquiphobic coating on aluminum surface with self-cleaning and anti-fogging properties.

    Science.gov (United States)

    Nanda, D; Varshney, P; Satapathy, M; Mohapatra, S S; Bhushan, B; Kumar, A

    2017-12-01

    The development of self-cleaning and anti-fogging durable superliquiphobic coatings for aluminum surfaces has raised tremendous interest in materials science. In this study, a superliquiphobic coating is fabricated on an aluminum surface by a single-step dip-coating method using 1H,1H,2H,2H-Perfluorooctyltrichlorosilane-modified SiO2 nanoparticles. The successful implementation of the aforesaid coating in different applications requires extensive investigations of its characteristics and stability. To understand the properties of the coating, surface morphology, contact angle, self-cleaning, anti-fogging, and water repellency were investigated under perturbation conditions. Additionally, the dynamics of water and oil on the coated sample also were studied. Furthermore, the durability of the coating also was examined by performing thermal, chemical, and mechanical stability tests. It was found that the coating is superliquiphobic for water, ethylene glycol, glycerol and hexadecane, and shows thermal, chemical, and mechanical stability. Further, it exhibits self-cleaning and anti-fogging properties. This approach can be applied to any size and shape aluminum surface; thus, it has great industrial applications. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Imaging textural variation in the acoustoelastic coefficient of aluminum using surface acoustic waves.

    Science.gov (United States)

    Ellwood, R; Stratoudaki, T; Sharples, S D; Clark, M; Somekh, M G

    2015-11-01

    Much interest has arisen in nonlinear acoustic techniques because of their reported sensitivity to variations in residual stress, fatigue life, and creep damage when compared to traditional linear ultrasonic techniques. However, there is also evidence that the nonlinear acoustic properties are also sensitive to material microstructure. As many industrially relevant materials have a polycrystalline structure, this could potentially complicate the monitoring of material processes when using nonlinear acoustics. Variations in the nonlinear acoustoelastic coefficient on the same length scale as the microstructure of a polycrystalline sample of aluminum are investigated in this paper. This is achieved by the development of a measurement protocol that allows imaging of the acoustoelastic response of a material across a samples surface at the same time as imaging the microstructure. The development, validation, and limitations of this technique are discussed. The nonlinear acoustic response is found to vary spatially by a large factor (>20) between different grains. A relationship is observed when the spatial variation of the acoustoelastic coefficient is compared to the variation in material microstructure.

  9. An Investigation on the Sinterability and the Compaction Behavior of Aluminum/Graphene Nanoplatelets (GNPs) Prepared by Powder Metallurgy

    Science.gov (United States)

    Saboori, A.; Novara, C.; Pavese, M.; Badini, C.; Giorgis, F.; Fino, P.

    2017-01-01

    In the present study, the densification response of Al matrix reinforced with different weight percentages (0, 0.5, 1.0, 1.5 and 2.0 wt.%) of graphene nanoplatelets (GNPs) was studied. These composites were produced by a wet method followed by a conventional powder metallurgy. The Raman spectrum of graphene indicates that preparation of the composites through the wet mixing method did not affect the disordering and defect density in the GNPs structure. The nanocomposite powder mixture was consolidated via a cold uniaxial compaction. The samples were sintered at different temperatures (540, 580 and 620 °C) under nitrogen flow so as to assess the sinterability of the nanocomposites. X-ray diffraction (XRD) has been carried out to check the possible reaction between GNPs and aluminum. According to the XRD patterns, it seems that Al4C3 did not form during the fabrication process. The relative density, compressibility, sinterability and Vickers hardness of the nanocomposites were also evaluated. The effects of GNPs on the consolidation behavior of the matrix were studied using the Heckel, Panelli and Ambrosio Filho, and Ge equations. The outcomes show that at early stage of consolidation the rearrangement of particles is dominant, while by increasing the compaction pressure, due to the load partitioning effect of GNPs, the densification rate of the powder mixture decreases. Moreover, the fabricated nanocomposites exhibited high Vickers hardness of 67 HV5, which is approximately 50% higher than monolithic aluminum. The effect of graphene addition on the thermal conductivity of Al/GNPs nanocomposites was evaluated by means of thermal diffusivity measurement, and the results showed that the higher thermal conductivity can be only achieved at lower graphene content.

  10. Preparation and Characterization of Plasma Electrolytic Oxidation Coating on 5005 Aluminum Alloy with Red Mud as an Electrolyte Additive

    Science.gov (United States)

    Liu, Shifeng; Zeng, Jianmin; Wang, Youbin

    2017-10-01

    A coating with red mud as an electrolyte additive was applied to 5005 aluminum alloy using plasma electrolytic oxidation (PEO). The phase composition of the coating was investigated using X-ray diffraction. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) was used to determine the microstructure and composition profiles of the coating. The coating/substrate adhesion was determined by scratch testing. The corrosion behaviors of the substrate and coating were evaluated using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The results indicated that the PEO coating with red mud consisted mainly of α-Al2O3 and γ-Al2O3, with small amounts of Fe2O3, CaCO3, and CaTiO3. The surface of the coating was the color of the red mud. The coating had a uniform thickness of about 80 μm and consisted of two main layers: a 6- μm porous outer layer and a 74- μm dense inner layer, which showed typical metallurgical adhesion (coating/substrate adhesion strength of 59 N). The coating hardness was about 1142 HV, much higher than that of the substrate (60 HV). The corrosion potential E corr and corrosion current density i corr of the coating were estimated to be -0.743 V and 3.85 × 10-6 A cm-2 from the PDP curve in 3.5 wt pct NaCl solution, and the maximum impedance and phase angle of the coating were 11 000 Ω and -67 deg, respectively, based on EIS. PEO coating with red mud improved the surface properties and corrosion resistance of 5005 aluminum alloy. This study also shows a potential method for reusing red mud.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-08-01

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

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

    Science.gov (United States)

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

    2014-08-01

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

  13. Surface scanning inspection system particle detection dependence on aluminum film morphology

    Science.gov (United States)

    Prater, Walter; Tran, Natalie; McGarvey, Steve

    2012-03-01

    Physical vapor deposition (PVD) aluminum films present unique challenges when detecting particulate defects with a Surface Scanning Inspection System (SSIS). Aluminum (Al) films 4500Å thick were deposited on 300mm particle grade bare Si wafers at two temperatures using a Novellus Systems INOVA® NExT,.. Film surface roughness and morphology measurements were performed using a Veeco Vx310® atomic force microscope (AFM). AFM characterization found the high deposition temperature (TD) Al roughness (Root Mean Square 16.5 nm) to be five-times rougher than the low-TD Al roughness (rms 3.7 nm). High-TD Al had grooves at the grain boundaries that were measured to be 20 to 80 nm deep. Scanning electron microscopy (SEM) examination, with a Hitachi RS6000 defect review SEM, confirmed the presence of pronounced grain grooves. SEM images established that the low-TD filmed wafers have fine grains (0.1 to 0.3 um diameter) and the high-TD film wafers have fifty-times larger equiaxed plateletshape grains (5 to 15 um diameter). Calibrated Poly-Styrene Latex (PSL) spheres ranging in size from 90 nm to 1 μm were deposited in circular patterns on the wafers using an aerosol deposition chamber. PSL sphere depositions at each spot were controlled to yield 2000 to 5000 counts. A Hitachi LS9100® dark field full wafer SSIS was used to experimentally determine the relationship of the PSL sphere scattered light intensity with S-polarized light, a measure of scattering cross-section, with respect to the calibrated PSL sphere diameter. Comparison of the SSIS scattered light versus PSL spot size calibration curves shows two distinct differences. Scattering cross-section (intensity) of the PSL spheres increased on the low-TD Al film with smooth surface roughness and the low-TD Al film defect detection sensitivity was 126 nm compared to 200 nm for the rougher high- TD Al film. This can be explained by the higher signal to noise attributed to the smooth low-TD Al. Dark field defect detection on

  14. Comparative Evaluation of Aluminum Sulfate and Ferric Sulfate-Induced Coagulations as Pretreatment of Microfiltration for Treatment of Surface Water.

    Science.gov (United States)

    Song, Yali; Dong, Bingzhi; Gao, Naiyun; Deng, Yang

    2015-06-12

    Two coagulants, aluminum sulfate and ferric chloride, were tested to reduce natural organic matter (NOM) as a pretreatment prior to polyvinylidene fluoride (PVDF) microfiltration (MF) membranes for potable water treatment. The results showed that the two coagulants exhibited different treatment performance in NOM removal. Molecular weight (MW) distributions of NOM in the tested surface raw water were concentrated at 3-5 kDa and approximately 0.2 kDa. Regardless of the coagulant species and dosages, the removal of 0.2 kDa NOM molecules was limited. In contrast, NOM at 3-5 kDa were readily removed with increasing coagulant dosages. In particular, aluminum sulfate favorably removed NOM near 5 kDa, whereas ferric chloride tended to reduce 3 kDa organic substances. Although aluminum sulfate and ferric chloride could improve the flux of the ensuing MF treatment, the optimal coagulant dosages to achieve effective pretreatment were different: 2-30 mg/L for aluminum sulfate and >15 mg/L for ferric chloride. The scanning electron microscope (SEM) image of the membrane-filtered coagulated raw water showed that coagulation efficiency dramatically affected membrane flux and that good coagulation properties can reduce membrane fouling.

  15. Comparative Evaluation of Aluminum Sulfate and Ferric Sulfate-Induced Coagulations as Pretreatment of Microfiltration for Treatment of Surface Water

    Directory of Open Access Journals (Sweden)

    Yali Song

    2015-06-01

    Full Text Available Two coagulants, aluminum sulfate and ferric chloride, were tested to reduce natural organic matter (NOM as a pretreatment prior to polyvinylidene fluoride (PVDF microfiltration (MF membranes for potable water treatment. The results showed that the two coagulants exhibited different treatment performance in NOM removal. Molecular weight (MW distributions of NOM in the tested surface raw water were concentrated at 3–5 kDa and approximately 0.2 kDa. Regardless of the coagulant species and dosages, the removal of 0.2 kDa NOM molecules was limited. In contrast, NOM at 3–5 kDa were readily removed with increasing coagulant dosages. In particular, aluminum sulfate favorably removed NOM near 5 kDa, whereas ferric chloride tended to reduce 3 kDa organic substances. Although aluminum sulfate and ferric chloride could improve the flux of the ensuing MF treatment, the optimal coagulant dosages to achieve effective pretreatment were different: 2–30 mg/L for aluminum sulfate and >15 mg/L for ferric chloride. The scanning electron microscope (SEM image of the membrane-filtered coagulated raw water showed that coagulation efficiency dramatically affected membrane flux and that good coagulation properties can reduce membrane fouling.

  16. Characterisation of the surface of freshly prepared precious metal catalysts.

    Science.gov (United States)

    Parker, Stewart F; Adroja, Devashibhai; Jiménez-Ruiz, Mónica; Tischer, Markus; Möbus, Konrad; Wieland, Stefan D; Albers, Peter

    2016-07-14

    A combination of electron microscopy, X-ray and neutron spectroscopies and computational methods has provided new insights into the species present on the surface of freshly prepared precious metal catalysts. The results show that in all cases, at least half of the surface is metallic or nearly so, with the remainder covered by oxygen, largely as hydroxide. Water is also present and is strongly held; weeks of pumping under high vacuum is insufficient to remove it. The hydroxyls are reactive as shown by their reaction with or displacement by CO and can be removed by hydrogenation. This clearly has implications for how precious metal catalysts are activated after preparation.

  17. Preparation and preliminary testing of cermet inert anode for aluminum electrolysis

    Institute of Scientific and Technical Information of China (English)

    李劼; 赖延清; 周科朝; 李志友; 刘业翔

    2003-01-01

    Recent development of inert anodes for the primary aluminium industry was reviewed. The preparation method of functionally gradient material was introduced into inert anode research area, and a research flow sheet of functionally gradient cermet inert anode was set down. In order to carry out the preparation and optimization of composite oxides as the ceramic matrix of cermet inert anode, the following problems: solid state reaction synthesis of complex oxides, corrosion mechanism of complex oxides in Na3AlF6-Al2O3 melts, effects of NiO content on the corrosion rate and resistivity at high temperature of NiFe2O4-NiO ceramics were studied. The preparation and sintering mechanism of NiFe2O4 based cermets were deeply studied to properly control the sintering atmosphere and temperature system. By efficaciously controlling the sintering atmosphere, the oxidization of metallic phase and the decomposition or deoxidization of ceramic phase are avoided effectively during the sintering process of cermets at various temperatures. By optimizing the composition recipe and sintering temperature system, cermets of relatively high density are prepared without the spillage or asymmetric distribution of metallic phase.

  18. Effects of MgO Nano Particles on Microstructural and Mechanical Properties of Aluminum Matrix Composite prepared via Powder Metallurgy Route

    Science.gov (United States)

    Baghchesara, Mohammad Amin; Abdizadeh, Hossein; Baharvandi, Hamid Reza

    The objective of the present investigation was to evaluate the microstructural and mechanical properties of Al/nano MgO composite prepared via powder metallurgy method. Pure atomized aluminum powder with an average particle size of 1μm and MgO particulate with an average particle size between 60 to 80 nm were used. Composites containing 1.5, 2.5 and 5 percent of volume fraction of MgO were prepared by powder metallurgy method. The specimens were pressed by Cold Isostatic Press machine (CIP), subsequently were sintered at 575, 600 and 625°C. After sintering and preparing the samples, mechanical properties were measured. The results of microstructure, compression and hardness tests indicated that addition of MgO particulates to aluminum matrix composites improves the mechanical properties.

  19. Chlorodiethylaluminum supported on silica: A dinuclear aluminum surface species with bridging μ2-Cl-ligand as a highly efficient co-catalyst for the Ni-catalyzed dimerization of ethene

    KAUST Repository

    Kermagoret, Anthony

    2014-05-01

    Silica-supported chloro alkyl aluminum co-catalysts (DEAC@support) were prepared via Surface Organometallic Chemistry by contacting diethylaluminum chloride (DEAC) and high specific surface silica materials, i.e. SBA-15, MCM-41, and Aerosil SiO2. Such systems efficiently activate NiCl 2(PBu3)2 for catalytic ethene dimerization, with turnover frequency (TOF) reaching up to 498,000 molC2H4/ (molNi h) for DEAC@MCM-41. A detailed analysis of the DEAC@SBA-15 co-catalyst structure by solid-state aluminum-27 NMR at high-field (17.6 T and 20.0 T) and ultrafast spinning rates allows to detect six sites, characterized by a distribution of quadrupolar interaction principal values CQ and isotropic chemical shifts δiso. Identification of the corresponding Al-grafted structures was possible by comparison of the experimental NMR signatures with these calculated by DFT on a wide range of models for the aluminum species (mono- versus di-nuclear, mono- versus bis-grafted with bridging Cl or ethyl). Most of the sites were identified as dinuclear species with retention of the structure of DEAC, namely with the presence of μ2-Cl-ligands between two aluminum, and this probably explains the high catalytic performance of this silica-supported co-catalysts. © 2014 Elsevier Inc. All rights reserved.

  20. Characterization of Aluminum-Based-Surface Matrix Composites with Iron and Iron Oxide Fabricated by Friction Stir Processing

    Directory of Open Access Journals (Sweden)

    Essam R. I. Mahmoud

    2016-06-01

    Full Text Available Surface composite layers were successfully fabricated on an A 1050-H24 aluminum plate by dispersed iron (Fe and magnetite (Fe3O4 particles through friction stir processing (FSP. Fe and Fe3O4 powders were packed into a groove of 3 mm in width and 1.5 mm in depth, cut on the aluminum plate, and covered with an aluminum sheet that was 2-mm thick. A friction stir processing (FSP tool of square probe shape, rotated at a rate of 1000–2000 rpm, was plunged into the plate through the cover sheet and the groove, and moved along the groove at a travelling speed of 1.66 mm/s. Double and triple passes were applied. As a result, it is found that the Fe particles were homogenously distributed in the whole nugget zone at a rotation speed of 1000 rpm after triple FSP passes. Limited interfacial reactions occurred between the Fe particles and the aluminum matrix. On the other hand, the lower rotation speed (1000 rpm was not enough to form a sound nugget when the dispersed particles were changed to the larger Fe3O4. The Fe3O4 particles were dispersed homogenously in a sound nugget zone when the rotation speed was increased to 1500 rpm. No reaction products could be detected between the Fe3O4 particles and the aluminum matrix. The saturation magnetization (Ms of the Fe-dispersed nugget zone was higher than that of the Fe3O4-dispersed nugget zone. Moreover, there were good agreement between the obtained saturation magnetization values relative to that of pure Fe and Fe3O4 materials and the volume content of the dispersed particles in the nugget zone.

  1. STM characterization of MOVPE-prepared silicon surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kleinschmidt, Peter; Brueckner, Sebastian; Luczak, Johannes; Supplie, Oliver; Dobrich, Anja; Doescher, Henning; Hannappel, Thomas [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany)

    2011-07-01

    The clean Si(100) surface reconstructs by forming dimers, thus reducing the number of dangling bonds at the surface. In the MOVPE environment hydrogen is commonly used as process gas, which leads to a monohydride silicon surface with a 2 x 1 unit cell consisting of H-Si-Si-H dimers. Even so, the quality of the surface can vary dramatically depending on process conditions. In general, annealing in hydrogen leads to a two-domain surface structure with monoatomic steps, where the resulting structure also strongly depends on misorientation. We find process conditions for preparation of Si(100) surfaces with 0.1 , 2 and 6 offcut where a strong preference for one domain is obtained, making the resulting surfaces ideal substrates for III-V-on-Si epitaxy. A process consisting of deoxidation, homoepitaxial buffer layer growth and annealing is found to result in D{sub A}-type double layer steps for 0.1 , and D{sub B}-type double layer steps for 6 offcut. The identical process leads to single layer steps for 2 offcut. Here, we obtain D{sub A}-type double layer steps by a modified process which includes a slow cooling phase after the annealing step. Our results, verified by scanning tunneling microscopy, low energy electron diffraction and Fourier-transform infrared spectroscopy, are in sharp contrast to the clean and the hydrogenated Si(100) surface prepared in UHV.

  2. Preparation and characterization of TiO2 photoelectrode codoped with aluminum and boron and its application in dye-sensitized solar cell

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiaoling; ZENG Peng; HU Shejun; KUANG Tongchun; XIE Guangrong; GAO Feng

    2006-01-01

    Nanocrystalline titania films codoped with aluminum and boron were prepared by cathodic vacuum arc deposition. In the process, titanium alloy target was used under an O2/Ar atmosphere, and sensitization of films were carried out by natural dye-sensitized complex in anhydrous ethanol. The structure, surface morphology and UV-vis spectra of titania films codoped were measured by X-ray diffraction analysis, scanning electron microscopy and ultraviolet-visible spectrometer. Theas-deposited films are found to be amorphous. The films annealed were examinedto be of anatase structure with orientation along the (101) planes, the averagecrystal size is in the range between 41 and 45 nm. SEM results show that thereare some pores in the codoped titania films, the optical properties of the dye-sensitized films were also measured which reveals that the spectral responses of films shift to the visible region. Under simulated sunlight illumination, the overall energy conversion efficiency of dye-sensitized nanocrystalline solar cell is 0.9%.

  3. Preparation and characterization of porous granular ceramic containing dispersed aluminum and iron oxides as adsorbents for fluoride removal from aqueous solution.

    Science.gov (United States)

    Chen, Nan; Zhang, Zhenya; Feng, Chuanping; Zhu, Dirui; Yang, Yingnan; Sugiura, Norio

    2011-02-15

    Porous granular ceramic adsorbents containing dispersed aluminum and iron oxides were synthesized by impregnating with salt solutions followed by precipitation at 600°C. In the present work detailed studies were carried out to investigate the effect of contact time, adsorbent dose, initial solution pH and co-existing anions. Characterization studies on the adsorbent by SEM, XRD, EDS, and BET analysis were carried out to clarify the adsorption mechanism. The adsorbents were sphere in shape, 2-3mm in particle size, highly porous and showed specific surface area of 50.69 sq m/g. The fluoride adsorption capacity of prepared adsorbent was 1.79 mg/g, and the maximum fluoride removal was obtained at pH 6. Both the Langmuir and Freundlich isotherm models were found to represent the measured adsorption data well. The experimental data were well explained with pseudo-second-order kinetic model. Results from this study demonstrated potential utility of Al/Fe dispersed in porous granular ceramics that could be developed into a viable technology for fluoride removal from aqueous solution. Copyright © 2010 Elsevier B.V. All rights reserved.

  4. A corrosion resistant cerium oxide based coating on aluminum alloy 2024 prepared by brush plating

    Energy Technology Data Exchange (ETDEWEB)

    Tang Junlei; Han Zhongzhi [School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Zuo Yu, E-mail: zuoy@mail.buct.edu.cn [School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Tang Yuming [School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)

    2011-01-15

    Cerium oxide based coatings were prepared on AA2024 Al alloy by brush plating. The characteristic of this technology is that hydrogen peroxide, which usually causes the plating solution to be unstable, is not necessary in the plating electrolyte. The coating showed laminated structures and good adhesive strength with the substrate. X-ray diffraction and X-ray photoelectron spectroscopy analysis showed that the coatings were composed of Ce(III) and Ce(IV) oxides. The brush plated coatings on Al alloys improved corrosion resistance. The influence of plating parameters on structure and corrosion resistance of the cerium oxide based coating was studied.

  5. Fabrication of carbon nanofiber-reinforced aluminum matrix composites assisted by aluminum coating formed on nanofiber surface by in situ chemical vapor deposition

    Science.gov (United States)

    Ogawa, Fumio; Masuda, Chitoshi

    2015-01-01

    The van der Waals agglomeration of carbon nanofibers (CNFs) and the weight difference and poor wettability between CNFs and aluminum hinder the fabrication of dense CNF-reinforced aluminum matrix composites with superior properties. In this study, to improve this situation, CNFs were coated with aluminum by a simple and low-cost in situ chemical vapor deposition (in situ CVD). Iodine was used to accelerate the transport of aluminum atoms. The coating layer formed by the in situ CVD was characterized using scanning electron microscopy, transmission electron microscopy, x-ray diffraction, Fourier transform-infrared spectroscopy, and x-ray photoelectron spectroscopy. The results confirmed that the CNFs were successfully coated with aluminum. The composites were fabricated to investigate the effect of the aluminum coating formed on the CNFs. The dispersion of CNFs, density, Vickers micro-hardness and thermal conductivity of the composites fabricated by powder metallurgy were improved. Pressure-less infiltration experiments were conducted to fabricate composites by casting. The results demonstrated that the wettability and infiltration were dramatically improved by the aluminum coating layer on CNFs. The aluminum coating formed by the in situ CVD technique was proved to be effective for the fabrication of CNF-reinforced aluminum matrix composites.

  6. HIGH VELOCITY THERMAL GUN FOR SURFACE PREPARATION AND TREATMENT

    Directory of Open Access Journals (Sweden)

    I.A. Gorlach

    2012-01-01

    Full Text Available Many surface preparation and treatment processes utilise compressed air to propel particles against surfaces in order to clean and treat them. The effectiveness of the processes depends on the velocity of the particles, which in turn depends on the pressure of the compressed air. This paper describes a thermal gun built on the principles of High Velocity Air Fuel (HVAF and High Velocity Oxy Fuel (HVOF processes. The designed apparatus can be used for abrasive blasting, coating of surfaces, cutting of rocks, removing rubber from mining equipment, cleaning of contaminations etc.

  7. Analysis of surface orange peel of aluminum-alloy automobile sheet by using of EBSD and X-ray diffraction

    Institute of Scientific and Technical Information of China (English)

    Ma Mingtu; Sun Zhifu; Wang Zhiwe; Lu Hongzhou; Zhou Mingbo

    2012-01-01

    The formation cause of orange peel of aluminum-alloy automotive sheet after tensile deformation was analysed by using X-ray diffraction and electron back-scattered diffraction (EBSD). The test results showed that formation cause of surface orange peel after tensile deformation related to product texture and nonuniform deformation during the tensile process. The grain size has significant effect on deformation uniform and texture formation. Coarse grains were easy to produce nonuniform deformation and texture, which would produce surface orange peel after tensile deformation.

  8. Chemical equilibrium modeling of organic acids, pH, aluminum, and iron in Swedish surface waters.

    Science.gov (United States)

    Sjöstedt, Carin S; Gustafsson, Jon Petter; Köhler, Stephan J

    2010-11-15

    A consistent chemical equilibrium model that calculates pH from charge balance constraints and aluminum and iron speciation in the presence of natural organic matter is presented. The model requires input data for total aluminum, iron, organic carbon, fluoride, sulfate, and charge balance ANC. The model is calibrated to pH measurements (n = 322) by adjusting the fraction of active organic matter only, which results in an error of pH prediction on average below 0.2 pH units. The small systematic discrepancy between the analytical results for the monomeric aluminum fractionation and the model results is corrected for separately for two different fractionation techniques (n = 499) and validated on a large number (n = 3419) of geographically widely spread samples all over Sweden. The resulting average error for inorganic monomeric aluminum is around 1 µM. In its present form the model is the first internally consistent modeling approach for Sweden and may now be used as a tool for environmental quality management. Soil gibbsite with a log *Ks of 8.29 at 25°C together with a pH dependent loading function that uses molar Al/C ratios describes the amount of aluminum in solution in the presence of organic matter if the pH is roughly above 6.0.

  9. Preparation and characterization of solid-state sintered aluminum-doped zinc oxide with different alumina contents

    Indian Academy of Sciences (India)

    Yu-Hsien Chou; J L H Chau; W L Wang; C S Chen; S H Wang; C C Yang

    2011-06-01

    Aluminum-doped zinc oxide (AZO) ceramics with 0−2.5 wt.% alumina (Al2O3) content were prepared using a solid-state reaction technique. It was found that AZO grains became finer in size and more irregular in shape than undoped ZnO as the Al2O3 content increased. Addition of Al2O3 dopant caused the formation of phase transformation stacking faults in ZnO grains. The second phase, ZnAl2O4 spinel, was observed at the grain boundaries and triple junctions, and inside the grains. In this study, a 3-inch circular Al2O3 (2 wt.%)-doped ZnO ceramic target sintered at 1500°C for 6 h has a relative density of 99.8% with a resistivity of 1.8 × 10-3 -cm. The AZO film exhibits optical transparency of 90.3% in the visible region and shows an electrical resistivity of 2.5 × 10-3 -cm.

  10. Preparation and Wear Resistance of Aluminum Composites Reinforced with In Situ Formed TiO/Al2O3

    Science.gov (United States)

    Qin, Q. D.; Huang, B. W.; Li, W.; Zeng, Z. Y.

    2016-05-01

    An in situ TiO/Al2O3-reinforced Al composite is successfully prepared using a powder metallurgy route by the reaction of Ti2CO and Al powder. The Ti2CO powder is produced by carrying out a carbothermic reduction of titanium dioxide at 1000 °C. XRD results show that the final product is composed of Al, TiO, Al2O3, and Al3Ti. Morphology examination of the composite reveals the presence of bigger blocks of TiO and fine particles of Al2O3 and the volume fraction of reinforcement is found to range between 18 and 55%. As the volume fraction of the reinforced materials approaches 50%, the particles start to agglomerate. Dry sliding wear tests conducted using a conventional pin-on-disk testing machine show that the wear resistance of the composite is higher than that of the pure aluminum ingot. The wear rate of the composite increases almost linearly with the increase in the wear distance. The sliding wear test shows that as the volume fraction of the reinforced phase increases, the coefficient of friction decreases. The wear mechanism is also discussed.

  11. Controlled preparation of aluminum borate powders for the development of defect-related phosphors for warm white LED lighting

    Science.gov (United States)

    Guimarães, Vinicius F.; Salaün, Mathieu; Burner, Pauline; Maia, Lauro J. Q.; Ferrier, Alban; Viana, Bruno; Gautier-Luneau, Isabelle; Ibanez, Alain

    2017-03-01

    The optimization of the elaboration conditions of a new family of highly emissive white phosphors based on glassy yttrium aluminum borates (g-YAB) compositions is presented. Their preparation from solutions is based on the polymeric precursor method (modified Pechini process), involving non-toxic and low cost precursors. The resulting resins were first dried at moderate temperatures followed by two-step annealing treatments of the obtain powders under controlled atmospheres: a first pyrolysis under nitrogen followed by a calcination under oxygen. This favored the gradual oxidation of organic moieties coming from starting materials, avoiding uncontrolled self-combustion reactions, which generate localized hot spots. This prevented phase segregations and the formation of pyrolytic carbon or carbonates, which are strongly detrimental to the luminescence properties. Thus, coupled chemical analyses and luminescence characterizations showed the high chemical homogeneity of the resulting powders and their intense emissions in the whole visible range. These emissions can be tuned from blue to warm white by adjusting the calcination temperature that is an important advantage for the development of LED devices. We showed that impurities of monovalent and divalent cations act as quenching emission centers for these phosphors. Therefore, by increasing the purity grade, we significantly enhanced the PL emissions leading to high internal quantum yields (80-90%). Finally, cathodoluminescence emissions showed the homogeneous dispersion of emitting centers in the g-YAB matrix.

  12. Cratering and penetration experiments in aluminum and teflon: Implications for space-exposed surfaces

    Science.gov (United States)

    Hörz, Friedrich

    2012-04-01

    of either crater diameter or penetration-hole size in Al1100 and TeflonFEP targets of arbitrary thickness. We also placed witness plates behind penetrated targets to intercept the down-range debris plume, which is generally a mixture of both target and impactor fragments and melts. These witness plates also reveal that the debris plume systematically and diagnostically depends on D*. Thick targets shed spall debris only, and target thickness must be less than crater depth (Tc) to allow projectile material on the witness plate. Concentric plume patterns, accented by characteristic "hole saw" rings, characterize penetrated Al-targets at D* = 1-10, but they give way to distinctly radial geometries at D* = 10-20. Most of the target debris occupies the periphery of the plume, while the projectile fragments or melts reside in its central parts. The periphery of the plume is also typically more fine-grained than its center. At D* > 50, the exit plume is dominated by solid projectile fragments that progressively coagulate and overlap with each other, giving rise to compound craters. The latter have irregular crater interiors on account of the heterogeneous mass distribution of a collisionally produced, aggregate impactor. Similarly, complex craters are observed on LDEF and Stardust and they are produced by aggregate cosmic-dust particles containing large, dense components within a relatively low-density, fine-grained matrix. The witness-plate observations can also be used to address the enigmatic clustering of impact sites observed on Stardust's aerogel and aluminum surfaces. We suggest that this clustering is difficult to produce by the collision of particles from comet Wild 2 with the Stardust spacecraft, and that it is more likely due to particle disaggregation in the comet's coma.

  13. Detection of lead (pb and aluminum (Al metal as contaminant in food prepared by using locally manufactured cooked pots (Hala in Kosti City, Sudan

    Directory of Open Access Journals (Sweden)

    EI Salah

    2015-06-01

    Full Text Available The objectives of this study are to assess the quantities of Aluminu m; lead released into the food from locally manufactured cooked pots (Aluminium pots in Kosti market. Seven types of pots (Pistons, Cartels, Kettles, Kettles + trays, Pepsi cans, Atmonia and Steel which is locally manufactured cooked pots (Hala were used. Amount of Al and Pb that leaked into the food from locally manufactured cooked pots were assessed by using Atomic Absorption Spectroscopy. The results were indicated that highly significance amount of Aluminum and lead which were leaked into the food that prepared by locally manufactured cooked pots (Hala.The analysis of urine for 10 selected randomly individuals that used locally manufactured cooked pots (Hala for preparation their food were indicated highly amount of Aluminum and Lead in their urine. DOI: http://dx.doi.org/10.3126/ije.v4i2.12621 International Journal of Environment Vol.4(2 2015: 19-26

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

    Science.gov (United States)

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

    2014-07-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Bertram, F., E-mail: florian.bertram@sljus.lu.se; Evertsson, J.; Messing, M. E.; Mikkelsen, A.; Lundgren, E. [Division of Synchrotron Radiation Research, Lund University, Box 118, 221 00 Lund (Sweden); Zhang, F.; Pan, J. [KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Division of Surface and Corrosion Science, Drottning Kristinas väg 51, 10044 Stockholm (Sweden); Carlà, F. [ESRF, B. P. 220, 38043 Grenoble (France); Nilsson, J.-O. [Sapa Technology, Kanalgatan 1, 612 31 Finspång (Sweden)

    2014-07-21

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

  16. Copper ion implanted aluminum nitride dilute magnetic semiconductors (DMS) prepared by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Shah, A., E-mail: attaullah77@yahoo.com [National Institute of Lasers and Optronics (NILOP), PO Nilore, Islamabad (Pakistan); DMME, Pakistan Institute of Engineering and Applied Science (PIEAS), PO Nilore, Islamabad (Pakistan); Ahmad, Jamil [DMME, Pakistan Institute of Engineering and Applied Science (PIEAS), PO Nilore, Islamabad (Pakistan); Ahmad, Ishaq [Experimental Physics Lab, National Center for Physics (NCP), Islamabad (Pakistan); Mehmood, Mazhar [DMME, Pakistan Institute of Engineering and Applied Science (PIEAS), PO Nilore, Islamabad (Pakistan); Mahmood, Arshad [National Institute of Lasers and Optronics (NILOP), PO Nilore, Islamabad (Pakistan); Rasheed, Muhammad Asim [DMME, Pakistan Institute of Engineering and Applied Science (PIEAS), PO Nilore, Islamabad (Pakistan)

    2014-10-30

    Highlights: • AlN:Cu dilute magnetic semiconductors were successfully prepared by molecular beam epitaxy followed by Cu{sup +} implantation. • Room temperature ferromagnetism was observed after annealing the samples at appropriate temperature. • XRD and Raman spectrometry excluded the possibility of formation of any secondary phases. • By doping intrinsically nonmagnetic dopants (Cu), it has been proved experimentally that their precipitates do not contribute to ferromagnetism. • The reason for ferromagnetism in Cu-doped AlN as observed was explained on the basis of p–d hybridization mechanism (Wu et al.). - Abstract: Diluted magnetic semiconductor (DMS) AlN:Cu films were fabricated by implanting Cu{sup +} ions into AlN thin films at various ion fluxes. AlN films were deposited on c-plane sapphire by molecular beam epitaxy followed by Cu{sup +} ion implantation. The structural and magnetic characterization of the samples was performed through Rutherford backscattering and channeling spectrometry (RBS/C), X-ray diffraction (XRD), Raman spectroscopy, vibrating sample magnetometer (VSM) and SQUID. Incorporation of copper into the AlN lattice was confirmed by RBS, while XRD revealed that no new phase was formed as a result of ion implantation. RBS also indicated formation of defects as a result of implantation process and the depth and degree of damage increased with an increase in ion fluence. Raman spectra showed only E{sub 2} (high) and A{sub 1} (LO) modes of wurtzite AlN crystal structure and confirmed that no secondary phases were formed. It was found that both Raman modes shift with Cu{sup +} fluences, indicating that Cu ion may go to interstitial or substitutional sites resulting in distortion or damage of lattice. Although as implanted samples showed no magnetization, annealing of the samples resulted in appearance of room temperature ferromagnetism. The saturation magnetization increased with both the annealing temperature as well as with ion

  17. Effect of surface topological structure and chemical modification of flame sprayed aluminum coatings on the colonization of Cylindrotheca closterium on their surfaces

    Science.gov (United States)

    Chen, Xiuyong; He, Xiaoyan; Suo, Xinkun; Huang, Jing; Gong, Yongfeng; Liu, Yi; Li, Hua

    2016-12-01

    Biofouling is one of the major problems for the coatings used for protecting marine infrastructures during their long-term services. Regulation in surface structure and local chemistry is usually the key for adjusting antifouling performances of the coatings. In this study, flame sprayed multi-layered aluminum coatings with micropatterned surfaces were constructed and the effects of their surface structure and chemistry on the settlement of typical marine diatoms were investigated. Micropatterned topographical morphology of the coatings was constructed by employing steel mesh as a shielding plate during the coating deposition. A silicone elastomer layer for sealing and interconnection was further brush-coated on the micropatterned coatings. Additional surface modification was made using zwitterionic molecules via DOPA linkage. The surface-modified coatings resist effectively colonization of Cylindrotheca closterium. This is explained by the quantitative examination of a simplified conditioning layer that deteriorated adsorption of bovine calf serum proteins on the zwitterionic molecule-treated samples is revealed. The colonization behaviors of the marine diatoms are markedly influenced by the micropatterned topographical morphology. Either the surface micropatterning or the surface modification by zwitterionic molecules enhances antimicrobial ability of the coatings. However, the combined micropatterned structure and zwitterionic modification do not show synergistic effect. The results give insight into anti-corrosion/fouling applications of the modified aluminum coatings in the marine environment.

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

    Science.gov (United States)

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

    2015-09-01

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

  19. Gas-tungsten arc welding of aluminum alloys

    Science.gov (United States)

    Frye, Lowell D.

    1984-01-01

    A gas-tungsten arc welding method for joining together structures formed of aluminum alloy with these structures disposed contiguously to a heat-damagable substrate of a metal dissimilar to the aluminum alloy. The method of the present invention is practiced by diamond machining the fay surfaces of the aluminum alloy structures to provide a mirror finish thereon having a surface roughness in the order of about one microinch. The fay surfaces are aligned and heated sufficiently by the tungsten electrode to fuse the aluminum alloy contiguous to the fay surfaces to effect the weld joint. The heat input used to provide an oxide-free weld is significantly less than that required if the fay surfaces were prepared by using conventional chemical and mechanical practices.

  20. Effect of Equal Channel Angular Pressing on the Surface Roughness of Solid State Recycled Aluminum Alloy 6061 Chips

    Directory of Open Access Journals (Sweden)

    Adel Taha Abbas

    2017-01-01

    Full Text Available Solid state recycling through hot extrusion is a promising technique to recycle machining chips without remelting. Furthermore, equal channel angular pressing (ECAP technique coupled with the extruded recycled billet is introduced to enhance the mechanical properties of recycled samples. In this paper, the surface roughness of solid state recycled aluminum alloy 6061 turning chips was investigated. Aluminum chips were cold compacted and hot extruded under an extrusion ratio (ER of 5.2 at an extrusion temperature (ET of 425°C. In order to improve the properties of the extruded samples, they were subjected to ECAP up to three passes at room temperature using an ECAP die with a channel die angle (Φ of 90°. Surface roughness (Ra and Rz of the processed recycled billets machined by turning was investigated. Box-Behnken experimental design was used to investigate the effect of three machining parameters (cutting speed, feed rate, and depth of cut on the surface roughness of the machined specimens for four materials conditions, namely, extruded billet and postextrusion ECAP processed billets to one, two, and three passes. Quadratic models were developed to relate the machining parameters to surface roughness, and a multiobjective optimization scheme was conducted to maximize material removal rate while maintaining the roughness below a preset practical value.

  1. Influence of surface pretreatment in resistance spot welding of aluminum AA1050

    DEFF Research Database (Denmark)

    Al Naimi, Ihsan K.; Al Saadi, Moneer H.; Daws, Kasim M.

    2015-01-01

    Resistance spot welding (RSW) of aluminum alloys implies a major problem of inconsistent quality from weld to weld due to problems of varying thickness of the oxide layer. The high resistivity of oxide layer causes strong heat development, which has significant influence on electrode life and weld...

  2. Disturbance induced by surface preparation on instrumented indentation test

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yugang, E-mail: yugang.li@utt.fr [Université de Technologie de Troyes (UTT), ICD-LASMIS, UMR CNRS 6281, 12, rue Marie Curie-CS 42060, 10010 Troyes Cedex (France); Kanouté, Pascale, E-mail: pascale.kanoute@onera.fr [Université de Technologie de Troyes (UTT), ICD-LASMIS, UMR CNRS 6281, 12, rue Marie Curie-CS 42060, 10010 Troyes Cedex (France); The French Aerospace Lab (ONERA), DMSM/MCE, 29 avenue de la Division Leclerc-BP 72, F-92322 Chatillon Cedex (France); François, Manuel, E-mail: manuel.francois@utt.fr [Université de Technologie de Troyes (UTT), ICD-LASMIS, UMR CNRS 6281, 12, rue Marie Curie-CS 42060, 10010 Troyes Cedex (France)

    2015-08-26

    Surface preparation, which may induce considerable sample disturbance, plays an important role in instrumented indentation test (IIT). In this study, the sample disturbance (mainly divided into residual stresses and plastic strain) induced by the surface preparation process of instrumented indentation test specimens were investigated with both experimental tests and numerical simulations. Grazing incidence X-ray diffractions (GIXRD) and uniaxial tensile tests were conducted for characterizing the residual stresses and high plastic strain in the top surface layers of a carefully mechanically polished indentation sample, which, in the present work, is made of commercially pure titanium. Instrumented indentation tests and the corresponding finite element simulations were performed as well. For comparison, a reference sample (carefully mechanically polished & electrolytically polished) which represents the raw material was prepared and tested. Results showed that a careful mechanical polishing procedure can effectively reduce the level of residual stresses induced by this process. However, the high plastic strain in the surface region imposed by the polishing process is significant. The induced plastic strain can affect a depth up to 5 µm, which is deeper than the maximum penetration depth h{sub max} (3 µm) used for the instrumented indentation tests. In the near surface layer (in the range of depth about 350 nm), the plastic strain levels are fairly high. In the very top layer, the plastic strain was even estimated to reach more than 60%. The simultaneous use of indentation tests and numerical simulations showed that the existence of high plastic strain in the surface region will make the load vs depth (P–h) curve shift upwards, the contact hardness (H) increase and the contact stiffness (S) decrease.

  3. Electrostatic Self-Assembly of Diamond Nanoparticles onto Al- and N-Polar Sputtered Aluminum Nitride Surfaces

    Directory of Open Access Journals (Sweden)

    Taro Yoshikawa

    2016-11-01

    Full Text Available Electrostatic self-assembly of diamond nanoparticles (DNPs onto substrate surfaces (so-called nanodiamond seeding is a notable technique, enabling chemical vapor deposition (CVD of nanocrystalline diamond thin films on non-diamond substrates. In this study, we examine this technique onto differently polarized (either Al- or N-polar c-axis oriented sputtered aluminum nitride (AlN film surfaces. This investigation shows that Al-polar films, as compared to N-polar ones, obtain DNPs with higher density and more homogeneously on their surfaces. The origin of these differences in density and homogeneity is discussed based on the hydrolysis behavior of AlN surfaces in aqueous suspensions.

  4. Superhydrophobic and icephobic surfaces prepared by RF-sputtered polytetrafluoroethylene coatings

    Energy Technology Data Exchange (ETDEWEB)

    Jafari, R., E-mail: rjafari@uqac.ca [NSERC / Hydro-Quebec / UQAC Industrial Chair on Atmospheric Icing of Power Network Equipment (CIGELE) and Canada Research Chair on Engineering of Power Network Atmospheric Icing (INGIVRE), Universite du Quebec a Chicoutimi, Chicoutimi, QC (Canada); Menini, R.; Farzaneh, M. [NSERC / Hydro-Quebec / UQAC Industrial Chair on Atmospheric Icing of Power Network Equipment (CIGELE) and Canada Research Chair on Engineering of Power Network Atmospheric Icing (INGIVRE), Universite du Quebec a Chicoutimi, Chicoutimi, QC (Canada)

    2010-12-15

    A superhydrophobic and icephobic surface were investigated on aluminum alloy substrate. Anodizing was used first to create a micro-nanostructured aluminum oxide underlayer on the alloy substrate. In a second step, the rough surface was coated with RF-sputtered polytetrafluoroethylene (PTFE or Teflon). Scanning electron microscopy images showed a 'bird's nest'-like structure on the anodized surface. The RF-sputtered PTFE coating exhibited a high static contact angle of {approx}165 deg. with a very low contact angle hysteresis of {approx}3 deg. X-ray photoelectron spectroscopy (XPS) results showed high quantities of CF{sub 3} and CF{sub 2} groups, which are responsible for the hydrophobic behavior of the coatings. The performance of this superhydrophobic film was studied under atmospheric icing conditions. These results showed that on superhydrophobic surfaces ice-adhesion strength was 3.5 times lower than on the polished aluminum substrate.

  5. Facile preparation of superhydrophobic surfaces based on metal oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Xue-Mei; Cui, Jin-Feng; Sun, Han-Xue; Liang, Wei-Dong; Zhu, Zhao-Qi; An, Jin; Yang, Bao-Ping; La, Pei-Qing; Li, An, E-mail: lian2010@lut.cn

    2014-06-01

    A novel method for fabrication of superhydrophobic surfaces was developed by facile coating various metal oxide nanoparticles, including ZnO, Al{sub 2}O{sub 3} and Fe{sub 3}O{sub 4}, on various substrates followed by treatment with polydimethylsiloxane (PDMS) via chemical vapor deposition (CVD) method. Using ZnO nanoparticles as a model, the changes in the surface chemical composition and crystalline structures of the metal oxide nanoparticles by PDMS treatment were investigated by X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR) analysis. The results show that the combination of the improved surface roughness generated from of the nanoparticles aggregation with the low surface-energy of silicon-coating originated from the thermal pyrolysis of PDMS would be responsible for the surface superhydrophobicity. By a simple dip-coating method, we show that the metal oxide nanoparticles can be easily coated onto the surfaces of various textural and dimensional substrates, including glass slide, paper, fabric or sponge, for preparation of superhydrophobic surfaces for different purpose. The present strategy may provide an inexpensive and new route to surperhydrophobic surfaces, which would be of technological significance for various practical applications especially for separation of oils or organic contaminates from water.

  6. Facile preparation of superhydrophobic surfaces based on metal oxide nanoparticles

    Science.gov (United States)

    Bao, Xue-Mei; Cui, Jin-Feng; Sun, Han-Xue; Liang, Wei-Dong; Zhu, Zhao-Qi; An, Jin; Yang, Bao-Ping; La, Pei-Qing; Li, An

    2014-06-01

    A novel method for fabrication of superhydrophobic surfaces was developed by facile coating various metal oxide nanoparticles, including ZnO, Al2O3 and Fe3O4, on various substrates followed by treatment with polydimethylsiloxane (PDMS) via chemical vapor deposition (CVD) method. Using ZnO nanoparticles as a model, the changes in the surface chemical composition and crystalline structures of the metal oxide nanoparticles by PDMS treatment were investigated by X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR) analysis. The results show that the combination of the improved surface roughness generated from of the nanoparticles aggregation with the low surface-energy of silicon-coating originated from the thermal pyrolysis of PDMS would be responsible for the surface superhydrophobicity. By a simple dip-coating method, we show that the metal oxide nanoparticles can be easily coated onto the surfaces of various textural and dimensional substrates, including glass slide, paper, fabric or sponge, for preparation of superhydrophobic surfaces for different purpose. The present strategy may provide an inexpensive and new route to surperhydrophobic surfaces, which would be of technological significance for various practical applications especially for separation of oils or organic contaminates from water.

  7. AKD AND ASA MODEL SURFACES: PREPARATION AND CHARACTERIZATION

    Directory of Open Access Journals (Sweden)

    Janne Laine

    2007-11-01

    Full Text Available Model surfaces of alkyl ketene dimer (AKD and alkenyl succinic anhyd-ride (ASA were prepared by casting and spin-coating methods. The surface chemical composition and surface topography were investigated by XPS, ellipsometry, AFM and contact angle studies. Spin-coating resulted in layered structure of AKD and ASA surfaces; the molecular layer thickness of both AKD and ASA was found to be ca. 2.5 nm. To achieve a covering surface layer, an average thickness of ca. 35 nm was required. The rms roughness of the created surfaces was 1 - 6 nm. Colloidal probe adhesion measurements were performed to verify that the roughness was in a range suitable for these measurements. The high reactivity of ASA with water generated stability problems with the ASA layers and it has to be recognized that surface force measurements with ASA in aqueous environment are very difficult, if not impossible. How-ever, surfaces created in this way were found to be useful in providing explanations of earlier ASA adhesion studies. The contact angle measurements on ASA layers also indicated that it might be possible to asses the hydrolysis rate issues through a set of similar measurements.

  8. Sono-assisted preparation of magnetic magnesium-aluminum layered double hydroxides and their application for removing fluoride.

    Science.gov (United States)

    Chang, Qing; Zhu, Lihua; Luo, Zhihong; Lei, Min; Zhang, Suicheng; Tang, Heqing

    2011-03-01

    A simple ultrasound-assisted co-precipitation method in combination with a calcination treatment was developed to prepare magnetic Mg-Al layered double hydroxides composite as an adsorbent material to remove fluoride ions from aqueous solutions. The application of ultrasound in the preparation process promoted the formation of the hydrotalcite-like phase and drastically shortened the time being required for preparation of the crystalline composite. It was found that the ultrasound irradiation assistance decreased the size of the composite particles and increased the specific surface area, being favorable to the improvement of the adsorption capacity. The composite prepared under the ultrasound irradiation exhibited fairly high maximum adsorption capacity of fluoride (47.7 mg g(-1)), which was 60% higher than that of the composite prepared without the ultrasound irradiation assistance with the same aging time. The thermodynamic and kinetic studies demonstrated that the adsorption of fluoride ions involved the reconstruction of the layered structure in the composite. In addition, the magnetic composite can be effectively and simply separated by using an external magnetic field, and then regenerated by desorption and calcination. Copyright © 2010 Elsevier B.V. All rights reserved.

  9. Low-temperature preparation of rutile-type TiO2 thin films for optical coatings by aluminum doping

    Science.gov (United States)

    Ishii, Akihiro; Kobayashi, Kosei; Oikawa, Itaru; Kamegawa, Atsunori; Imura, Masaaki; Kanai, Toshimasa; Takamura, Hitoshi

    2017-08-01

    A rutile-type TiO2 thin film with a high refractive index (n), a low extinction coefficient (k) and small surface roughness (Ra) is required for use in a variety of optical coatings to improve the controllability of the reflection spectrum. In this study, Al-doped TiO2 thin films were prepared by pulsed laser deposition, and the effects of Al doping on their phases, optical properties, surface roughness and nanoscale microstructure, including Al distribution, were investigated. By doping 5 and 10 mol%Al, rutile-type TiO2 was successfully prepared under a PO2 of 0.5 Pa at 350-600 °C. The nanoscale phase separation in the Al-doped TiO2 thin films plays an important role in the formation of the rutile phase. The 10 mol%Al-doped rutile-type TiO2 thin film deposited at 350 °C showed excellent optical properties of n ≈ 3.05, k ≈ 0.01 (at λ = 400 nm) and negligible surface roughness, at Ra ≈ 0.8 nm. The advantages of the superior optical properties and small surface roughness of the 10 mol%Al-doped TiO2 thin film were confirmed by fabricating a ten-layered dielectric mirror.

  10. Analysis of surface roughening behavior of 6063 aluminum alloy by tensile testing of a trapezoidal uniaxial specimen

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yang [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150090 (China); Wang, Xiaosong, E-mail: hitxswang@hit.edu.cn [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150090 (China); National Key Laboratory of Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001 (China); Yuan, Shijian [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150090 (China); National Key Laboratory of Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001 (China)

    2016-08-30

    To determine the quantitative relationship between surface roughness and strain, the surface roughening behavior of a 6063 aluminum alloy tube was examined by tensile testing of a trapezoidal uniaxial specimen, that can provide a continuous strain distribution after tensile deformation. The surface roughness was measured using a laser scanning confocal microscope to reflect the degree of roughening. The microstructure and surface morphology were examined using electron back-scattered diffraction and in-situ scanning electron microscopy to determine the grain orientation and surface topography evolution. The surface roughness increased with strain when the strain was less than 0.067 and then decreased slightly, with a maximum surface roughness of 23.73 µm. Inhomogeneous deformation at the grain boundaries and inside the grains was enhanced with increasing strain, resulting in an increase of surface roughness when the strain was below a critical value. As the strain increased, a greater number of slip systems contributed to the further deformation. Thus, the strain became more homogeneous, and accordingly, the surface roughness slightly decreased.

  11. An investigation of the electrochemical action of the epoxy zinc-rich coatings containing surface modified aluminum nanoparticle

    Science.gov (United States)

    Jalili, M.; Rostami, M.; Ramezanzadeh, B.

    2015-02-01

    Aluminum nanoparticle was modified with amino trimethylene phosphonic acid (ATMP). The surface characterization of the nanoparticles was done by X-ray photo electron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis. The influence of the replacement of 2 wt% of zinc dust in the standard zinc-rich epoxy coating by nanoparticles on the electrochemical action of the coating was studied by electrochemical impedance spectroscopy (EIS) and salt spray tests. The morphology and phase composition of the zinc rich paints were evaluated by X-ray diffraction (XRD) and filed-emission scanning electron microscopy (FE-SEM). Results showed that the ATMP molecules successfully adsorbed on the surface of Al nanoparticles. Results obtained from salt spray and electrochemical measurements revealed that the addition of surface modified nanoparticles to the zinc rich coating enhanced its galvanic action and corrosion protection properties.

  12. Low Temperature Curing of Hydrogen Silsesquioxane Surface Coatings for Corrosion Protection of Aluminum

    DEFF Research Database (Denmark)

    Lampert, Felix; Jensen, Annemette Hindhede; Møller, Per

    2016-01-01

    Hydrogen Silsesquioxane (HSQ) has shown to be a promising precursor for corrosion protective glass coatings for metallic substrates due to the excellent barrier properties of the films, especially in the application of protective coatings for aluminum in the automotive industry where high chemical...... stability in alkaline environments is required. The coatings have been successfully applied to stainless steel substrates. However the traditional thermal curing of HSQ involves heating to elevated temperatures, which are beyond those applicable for most industrial applications of aluminum. In this study...... low temperature processes are tested and evaluated as possible alternatives to the traditional high temperature cure. Thin HSQ films are deposited onsilicon wafers to model the degree of curing induced by the low temperature methods in comparison to thermal curing.Furthermore, the coatings are applied...

  13. Flexible pulse-wave sensors from oriented aluminum nitride nanocolumns

    Science.gov (United States)

    Akiyama, Morito; Ueno, Naohiro; Nonaka, Kazuhiro; Tateyama, Hiroshi

    2003-03-01

    Flexible pulse-wave sensors were fabricated from density-packed oriented aluminum nitride nanocolumns prepared on aluminum foils. The nanocolumns were prepared by the rf magnetron sputtering method and were perpendicularly oriented to the aluminum foil surfaces. The sensor structure is laminated, and the structure contributes to avoiding unexpected leakage of an electric charge. The resulting sensor thickness is 50 μm. The sensor is flexible like aluminum foil and can respond to frequencies from 0.1 to over 100 Hz. The sensitivity of the sensor to pressure is proportional to the surface area. The sensor sensitively causes reversible charge signals that correlate with the pulse wave form, which contains significant information on arteriosclerosis and cardiopathy of a man sitting on it.

  14. PREPARATION AND SURFACE PROPERTIES OF ACRYLIC COPOLYMERS CONTAINING FLUORINATED MONOMERS

    Institute of Scientific and Technical Information of China (English)

    Tai-jiang Gui; Hao Wei; Ying Zhao; Xiu-lin Wang; Du-jin Wang; Duan-fu Xu

    2006-01-01

    A series of copolymers comprising butylmethacrylate, styrene, butylacrylate, hydroxypropyl acrylate and perfluoroalkyl methacrylate were synthesized by the free radical polymerization using BPO as an initiator. The surface property of the copolymer films was subsequently characterized. The contact angle measurements and energy dispersive analysis of X-ray (EDAX) show that the length and content ofperfluoroalkyl side chains in the copolymers are crucial for the preparation of the film with low surface energy. At a given content of fluorinated monomers in the copolymers, the longer the perfluoroalkyl side chain, the larger the water contact angle of the copolymer films will be. On the other hand, the higher the content of fluorinated monomers, the lower the surface energy is. The water contact angle increases with the increase of the fluorinated monomer content and reaches a plateau at 3 wt% of fluorinated monomer content.

  15. Studies of the structure and properties of Ni-P and Ni-P/Si3N4 surface layers deposited on aluminum by the electroless method

    Directory of Open Access Journals (Sweden)

    M. Trzaska

    2010-11-01

    Full Text Available Purpose: The paper presents the results of studies on the structure and properties of the nickel Ni-P surface layers and composite Ni-P/Si3N4 surface layers deposited on the surfaces of aluminum 1200 (A2 and its 7075 (PA9 alloy by the electroless method.Design/methodology/approach: The aluminum substrate, the sample surfaces were treated by: degreasing, etching and zincking. The composite layers were produced from a disperse Si3N4 ceramic phase with an amorphous structure and nanometric size grains.Findings: The structure of the ceramic disperse phase Si3N4 and the layer materials was determined. The topography and morphology of the layers were examined. The content of the Si3N4 phase in the layer material was determined. The microhardness of the Ni-P and Ni-P/Si3N4 layers and of the substrate material was examined. The adhesion of the nickel phosphorus and composite layers to the aluminum substrate was determined. The results of studies of the corrosion resistance of the layers are presented. The anodic polarization characteristics, corrosion current densities and corrosion potentials were determined. The results of measurements of the impedance characteristics and the counterpart results obtained by modeling with the use of equivalent electrical circuits are presented. Both the nickel Ni-P and composite Ni-P/Si3N4 layers ensure excellent properties of the aluminum products.Practical implications: A good quality of final the nickel Ni-P surface layers and composite Ni-P/Si3N4 surface layers on the surfaces of aluminum are obtained. The surface layers are characterized by high hardness, frictional wear resistance and ensure excellent protection of the aluminum substrate against corrosion.Originality/value: The produced nickel and composite surface layers have show high hardness as well as very good resistances not only to corrosion but also to mechanical wear.

  16. Aluminum surface layer strengthening using intense pulsed beam radiation of substrate film system

    Science.gov (United States)

    Klopotov, A. A.; Ivanov, Yu F.; Vlasov, V. A.; Kondratyuk, A. A.; Teresov, A. D.; Shugurov, V. V.; Petrikova, E. A.

    2016-11-01

    The paper presents formation of the substrate film system (Zr-Ti-Cu/Al) by electric arc spraying of cathode having the appropriate composition. It is shown that the intense beam radiation of the substrate film system is accompanied by formation of the multi-phase state, the microhardness of which exceeds the one of pure A7 aluminum by ≈4.5 times.

  17. Preparation of aluminum doped zinc oxide films with low resistivity and outstanding transparency by a sol–gel method for potential applications in perovskite solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xingyue; Shen, Heping; Zhou, Chen [State Key Laboratory of New Ceramics & Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 10084 (China); Lin, Shiwei [Key Laboratory of Ministry of Education for Advanced Materials in Tropical Island Resources, Hainan University, Haikou 570228 (China); Li, Xin [State Key Laboratory of New Ceramics & Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 10084 (China); Zhao, Xiaochong [State Key Laboratory of New Ceramics & Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 10084 (China); Science and Technology on Surface Physics and Chemistry Laboratory, Mianyang 621907 (China); Deng, Xiangyun [Key Laboratory of Ministry of Education for Advanced Materials in Tropical Island Resources, Hainan University, Haikou 570228 (China); College of Physics and Electronic Information, Tianjin, Normal University, Tianjin 300387 (China); Li, Jianbao [State Key Laboratory of New Ceramics & Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 10084 (China); Key Laboratory of Ministry of Education for Advanced Materials in Tropical Island Resources, Hainan University, Haikou 570228 (China); Lin, Hong [State Key Laboratory of New Ceramics & Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 10084 (China)

    2016-04-30

    Highly transparent and conductive aluminum doped zinc oxide (AZO) films were prepared by sol–gel method on the glass substrates. The effects of doping concentration, annealing temperature and facing direction during annealing on the structural, electrical and optical properties of AZO films were studied by performing a series of characterizations including X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, UV–vis spectrophotometry, four-point probe method and Hall effect measurement system. The results showed that the AZO films were wurtzite crystallized with c-axis preferred orientation. A minimum resistivity of 1.8 × 10{sup −3} Ω cm and a transmittance above 90% were obtained for the film doped with 1.5 at.% aluminum, annealed at 510 °C and faced-down in the oven, which was among the best performance of the currently reported works based on sol–gel process. Moreover, energy level analysis revealed that the AZO film has a work function of 4.3 eV, exhibiting great potential in perovskite solar cell applications. - Highlights: • Highly transparent and conductive AZO films were prepared by sol–gel based process. • Different facing directions during annealing had effects on the carrier mobility. • Less aluminum ions at the grain boundary would favor the carrier transport. • The potential of AZO film in the perovskite solar cell application was discussed.

  18. Control of back surface reflectance from aluminum alloyed contacts on silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Cudzinovic, M.; Sopori, B. [National Renewable Energy Lab., Golden, CO (United States)

    1996-05-01

    A process for forming highly reflective aluminum back contacts with low contact resistance to silicon solar cells is described. By controlling the process conditions, it is possible to vary the silicon/aluminum interface from a specular to a diffuse reflector while maintaining a high interface reflectance. The specular interface is found to be a uniform silicon/aluminum alloy layer a few angstroms thick that has epitaxially regrown on the silicon. The diffuse interface consists of randomly distributed (111) pyramids produced by crystallographic out-diffusion of the bulk silicon. The light trapping ability of the diffuse contact is found to be close to the theoretical limit. Both types of contacts are found to have specific contact resistivities of 10{sup {minus}5} {Omega}-cm{sup 2}. The process for forming the contacts involves illuminating the devices with tungsten halogen lamps. The process is rapid (under 100 s) and low temperature (peak temperature < 580{degrees}C), making it favorable for commercial solar cell fabrication.

  19. Preparation of Bioactive Titanium Surfaces via Fluoride and Fibronectin Retention

    Directory of Open Access Journals (Sweden)

    Carlos Nelson Elias

    2012-01-01

    Full Text Available Statement of Problem. The chemical or topographic modification of the dental implant surface can affect bone healing, promote accelerated osteogenesis, and increase bone-implant contact and bonding strength. Objective. In this work, the effects of dental implant surface treatment and fibronectin adsorption on the adhesion of osteoblasts were analyzed. Materials and Methods. Two titanium dental implants (Porous-acid etching and PorousNano-acid etching followed by fluoride ion modification were characterized by high-resolution scanning electron microscopy, atomic force microscopy, and X-ray diffraction before and after the incorporation of human plasma fibronectin (FN. The objective was to investigate the biofunctionalization of these surfaces and examine their effects on the interaction with osteoblastic cells. Results. The evaluation techniques used showed that the Porous and PorousNano implants have similar microstructural characteristics. Spectrophotometry demonstrated similar levels of fibronectin adsorption on both surfaces (80%. The association indexes of osteoblastic cells in FN-treated samples were significantly higher than those in samples without FN. The radioactivity values associated with the same samples, expressed as counts per minute (cpm, suggested that FN incorporation is an important determinant of the in vitro cytocompatibility of the surfaces. Conclusion. The preparation of bioactive titanium surfaces via fluoride and FN retention proved to be a useful treatment to optimize and to accelerate the osseointegration process for dental implants.

  20. Preparation of multifunctional Al-Mg alloy surface with hierarchical micro/nanostructures by selective chemical etching processes

    Science.gov (United States)

    Shi, Tian; Kong, Jianyi; Wang, Xingdong; Li, Xuewu

    2016-12-01

    A superamphiphobic aluminum magnesium alloy surface with enhanced anticorrosion behavior has been prepared in this work via a simple and low-cost method. By successively polishing, etching and boiling treatments, the multifunctional hierarchical binary structures composed of the labyrinth-like concave-convex microstructures and twisty nanoflakes have been prepared. Results indicate that a superhydrophobic contact angle of 160.5° and superoleophobic contact angle larger than 150° as well as low adhesive property to liquids are achieved after such structures being modified with fluoroalkyl-silane. Furthermore, the anticorrosion behaviors in seawater of as-prepared samples are characterized by electrochemical tests including the impedance spectroscopies, equivalent circuits fittings and polarization curves. It is found that the hierarchical micro/nanostructures accompanying with the modified coating are proved to possess the maximal coating coverage rate of 90.0% larger than microstructures of 85.9%, nanostructures of 83.8% and bare polished surface of 67.1% suggesting the optimal anticorrosion. Finally, a great potential application in concentrators for surface-enhanced Raman scattering (SERS) analysis of toxic and pollutive ions on the superamphiphobic surface is also confirmed. This work has wider significance in extending further applications of alloys in engineering and environmental detecting fields.

  1. Characteristics of colloidal aluminum nanoparticles prepared by nanosecond pulsed laser ablation in deionized water in presence of parallel external electric field

    Science.gov (United States)

    Mahdieh, Mohammad Hossein; Mozaffari, Hossein

    2017-10-01

    In this paper, we investigate experimentally the effect of electric field on the size, optical properties and crystal structure of colloidal nanoparticles (NPs) of aluminum prepared by nanosecond Pulsed Laser Ablation (PLA) in deionized water. The experiments were conducted for two different conditions, with and without the electric field parallel to the laser beam path and the results were compared. To study the influence of electric field, two polished parallel aluminum metals plates perpendicular to laser beam path were used as the electrodes. The NPs were synthesized for target in negative, positive and neutral polarities. The colloidal nanoparticles were characterized using the scanning electron microscopy (SEM), UV-vis absorption spectroscopy and X-ray Diffraction (XRD). The results indicate that initial charge on the target has strong effect on the size properties and concentration of the synthesized nanoparticles. The XRD patterns show that the structure of produced NPs with and without presence of electric field is Boehmite (AlOOH).

  2. Preparation and Properties of Aluminum Complex Grease%复合铝基润滑脂的制备及性能

    Institute of Scientific and Technical Information of China (English)

    蒋明俊; 郭小川; 熊晓龙

    2011-01-01

    复合铝基润滑脂是一种性能优良的多效润滑脂,尤其是泵送性能良好,适合于集中润滑系统,在冶金等行业获得广泛应用.考察了组成、工艺和添加剂对复合铝基润滑脂性能的影响,复合铝皂对环烷基油的稠化能力优于对石蜡基油的稠化能力,增大基础油黏度有利于改善润滑脂的性能,采用异丙醇铝三聚物比采用异丙醇铝制备复合铝基脂的工艺可靠、产品性能稳定,通过配方和工艺条件优化制备出的复合铝基润滑脂具有良好的性能:高滴点,良好的胶体安定性、机械安定性、氧化安定性,良好的抗水性、抗腐蚀性、抗磨性.%Aluminum complex grease is a kind of multifunction grease. It is suited to central lubrication system for which has good pump ability. It has been used extensively in metallurgy area. The effect of composition, condition and additives on the properties of aluminum complex grease has been discussed. The thickening ability of aluminum complex soap in paraffin oil is superior to that of aluminum complex soap in naphthene oil. Increasing viscosity of base oil can improve the properties of aluminum complex grease. The method of trioxyaluminum tri-isopropylate is superior to that of aluminum isopropylate, because the technology is stable and the property is good. By optimization of composition and condition, the high performance aluminum complex grease has been prepared. It possesses high dropping point, good colloidal stability, shear stability, oxidation stability, water resistance property, anti-corrosion and anti-wear property.

  3. Charpy Impact Response of the Cracked Aluminum Plates Repaired with FML Patches using the Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Faramarz Ashenai Ghasemi

    2016-09-01

    Full Text Available Here, the effect of fiber metal laminate (FMLs patches was studied for repairing of single-sided cracked aluminum plates experimentally to see their response to Charpy impact tests. The main desired parameters were composite patch lay-up, crack length, and crack angle each one in three levels. All experimental attempts generated and followed based on the design of experiments method by using of response surface methodology. The predicted energy absorption values obtained from the model were in good agreement with the experimental results. No matter the specimens were repaired or not, as the crack length was increased the energy absorption of the structure was decreased. The experimental results also showed that for lengthen cracks, increasing of the crack angle had more effect on energy absorption. Also it was observed that the patch lay-up effective on the impact response of the specimens. The more the metal layer was departed from the aluminum plate and the FML patches interfacial surface, the less energy was absorbed in the structure.

  4. Preparation and Characterization of Plasma Cu Surface Modified Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiangyu; TANG Bin; FAN Ailan; MA Yong; TIAN Linhai

    2012-01-01

    Cu modified layer was prepared on the surface of AISI304 stainless steel by plasma surface alloying technique.The effects of processing parameters on the thickness,surface topography,microstructure and chemical composition of Cu modified layer were characterized using glow discharge optical emission spectroscopy (GDOES),scanning electron microscopy (SEM) and X-ray diffraction (XRD).The experimental results show that the surface modified layer is a duplex layer (deposited + diffused layer) with thickness of about 26 μm under the optimum process parameters.The modified layer is mainly composed of a mixture of Cu and expanded austenite phase.The ball-on-disk results show that the modified layer possesses low friction coefficients (0.25) and excellent wear resistance (wear volume 0.005× 109 μm3).The Cu modified layer is very effective in killing the bacteria S.aureus.Meanwhile,no viable S.aureus is found after 3 h (100% killed) by contact with the Cu alloyed surface.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-09-30

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

  6. Process Conditions of Forming the Surface Layer of Aluminum Powder Product by Layer-by-layer Laser Sintering

    Science.gov (United States)

    Saprykina, N. A.; Saprykin, A. A.; Ibragimov, E. A.; Arkhipova, D. A.

    2016-07-01

    The paper presents data on state of the art in selective laser sintering of products. Layer-by-layer sintering is shown to be a future-oriented technology, making it possible to synthesize products of metal powder materials. Factors, influencing the quality of a sintered product, are revealed in the paper. It presents outcomes of experiments, focused on the dependence of surface layer thickness of sintered aluminum powder PA-4 on laser processing conditions. Basic factors, influencing the quality of a sintered surface layer include laser power, speeds of scanning and moving the laser beam on the layer of powder. Thickness of the sintered layer varies from 0.74 to 1.55 mm, as the result of changing the laser processing conditions.

  7. Electrodeposition of polypyrrole films on aluminum surfaces from a p-toluene sulfonic acid medium

    Directory of Open Access Journals (Sweden)

    Andréa Santos Liu

    2009-01-01

    Full Text Available Electrodeposition of polypyrrole films on aluminum from aqueous solutions containing p-toluene sulfonic acid and pyrrole was performed by cyclic voltammetry and galvanostatic technique. The influence of applied current density on the morphology of the films was studied by Scanning Electron Microscopy. The films displayed a cauliflower-like structure consisting of micro-spherical grains. This structure is related to dopand intercalation in the polymeric chain. Films deposited at higher current density were more susceptible to the formation of pores and defects along the polymeric chain than films deposited at lower current density. These pores allow the penetration of aggressive species, thereby favoring the corrosion process.

  8. Impulse transfer to the surface of aluminum and copper from a pulsed Nd: YAG laser

    Science.gov (United States)

    Xu, Bingzhang; Wang, Qingpu; Zhang, Xingyu; Zhao, Shenzi; Xia, Yueyuan; Mei, Liangmo; Wang, Xiangtai; Wang, Gongtong

    1993-10-01

    Impulse coupling coefficients in air from 1.06 μm, 10 ns, Nd: YAG pulsed-laser radiation to aluminum and copper targets are measured using the ballistic pendulum method in the laser power-density range from 2.0×108 W/cm2 to 4.0×109 W/cm2. A modified laser-supported detonation (LSD) wave and cylindrical blast wave theory incorporating the vaporization model is proposed to calculate the impulse coupling coefficients. It is found that the theoretical results obtained with the modified model agree well with the experimental data.

  9. Study on adhesively-bonded surface of tapered double cantilever specimen made of aluminum foam affected with shear force

    Institute of Scientific and Technical Information of China (English)

    孙洪鹏; CHO Jae-ung

    2015-01-01

    Aluminum foam is widely used in diverse areas to minimize the weight and maximize the absorption of shock energy in lightweight structures and various bio-materials. It presents a number of advantages, such as low density, incombustibility, non-rigidity, excellent energy absorptivity, sound absorptivity and low heat conductivity. The aluminum foam with an air cell structure was placed under the TDCB Mode II tensile load by using Landmark equipment manufactured by MTS to examine the shear failure behavior. The angle of the tapered adhesively-bonded surfaces of specimens was designated as a variable, and three models were developed with the inclined angles differing from one another at 6°, 8° and 10°. The specimens with the inclined angles of 6°, 8° and 10° have the maximum reaction forces of 168 N, 194 N when the forced displacements are 6, 5 and 4.2 mm respectively. There are three specimens with the inclined angles of 10°, 8° and 6° in the order of maximum reaction force. As the analysis result, the maximum equivalent stresses of 0.813 MPa and 0.895 MPa happened when the forced displacements of 6 mm and 5 mm proceeded at the models of 6° and 8°, respectively. A simulation was carried out on the basis of finite element method and the experimental design. The results of the experiment and the simulation analysis are shown not different from each other significantly. Thus, only a simulation could be confirmed to be performed in substitution of an experiment, which is costly and time-consuming in order to determine the shearing properties of materials made of aluminum foam with artificial data.

  10. Amorphization and thermal stability of aluminum-based nanoparticles prepared from the rapid cooling of nanodroplets: effect of iron addition.

    Science.gov (United States)

    Xiao, Shifang; Li, Xiaofan; Deng, Huiqiu; Deng, Lei; Hu, Wangyu

    2015-03-07

    Despite an intensive investigation on bimetallic nanoparticles, little attention has been paid to their amorphization in the past few decades. The study of amorphization on a nanoscale is of considerable significance for the preparation of amorphous nanoparticles and bulk metallic glass. Herein, we pursue the amorphization process of Al-based nanoparticles with classic molecular dynamics simulations and local structural analysis techniques. By a comparative study of the amorphization of pure Al and Fe-doped Al-based nanodroplets in the course of rapid cooling, we find that Fe addition plays a very important role in the vitrification of Al-based nanodroplets. Owing to the subsurface segregated Fe atoms with their nearest neighbors tending to form relatively stable icosahedral (ICO) clusters, the Fe-centred cluster network near the surface effectively suppresses the crystallization of droplets from surface nucleation and growth as the concentration of Fe attains a certain value. The glass formation ability of nanodroplets is suggested to be enhanced by the high intrinsic inner pressure as a result of small size and surface tension, combined with the dopant-inhibited surface nucleation. In addition, the effect of the size and the added concentration of nanoparticles on amorphization and the thermal stability of the amorphous nanoparticles are discussed. Our findings reveal the amorphization mechanism in Fe-doped Al-based nanoparticles and provide a theoretical guidance for the design of amorphous materials.

  11. Investigation on microstructural and mechanical properties of B4C–aluminum matrix composites prepared by microwave sintering

    Directory of Open Access Journals (Sweden)

    Ehsan Ghasali

    2015-10-01

    Full Text Available B4C reinforced aluminum composites were fabricated by microwave heating of the mixture of B4C (10, 15 and 20 wt% and aluminum powders at 650, 750, 850 and 950 °C. The effect of different amounts of B4C on the microstructure and mechanical properties of aluminum matrix was examined. The maximum bending (238 ± 10 MPa and compressive strength (330 ± 10 MPa values were measured for composites sintered at 950 and 750 °C, respectively. The maximum hardness (112 Vickers was measured for Al–20 wt% B4C composite sintered at 850 °C. XRD investigations showed the decomposition of boron carbide and also the formation of Al3BC by heating the composites at 850 °C. SEM micrographs showed uniform distribution of reinforcement particles in Al matrix.

  12. Study on the Surface Integrity of a Thin-Walled Aluminum Alloy Structure after a Bilateral Slid Rolling Process

    Directory of Open Access Journals (Sweden)

    Laixiao Lu

    2016-04-01

    Full Text Available For studying the influence of a bilateral slid rolling process (BSRP on the surface integrity of a thin-walled aluminum alloy structure, and revealing the generation mechanism of residual stresses, a self-designed BSRP appliance was used to conduct rolling experiments. With the aid of a surface optical profiler, an X-ray stress analyzer, and a scanning electron microscope (SEM, the differences in surface integrity before and after BSRP were explored. The internal changing mechanism of physical as well as mechanical properties was probed. The results show that surface roughness (Ra is reduced by 23.7%, microhardness is increased by 21.6%, and the depth of the hardening layer is about 100 μm. Serious plastic deformation was observed within the subsurface of the rolled region. The residual stress distributions along the depth of the rolling surface and milling surface were tested respectively. Residual stresses with deep and high amplitudes were generated via the BSRP. Based on the analysis of the microstructure, the generation mechanism of the residual stresses was probed. The residual stress of the rolling area consisted of two sections: microscopic stresses caused by local plastic deformation and macroscopic stresses caused by overall non-uniform deformation.

  13. Influence of the molecular-oriented structure of ionic liquids on the crystallinity of aluminum hydroxide prepared by a sol-gel process in ionic liquids.

    Science.gov (United States)

    Kinoshita, K; Yanagimoto, H; Suzuki, T; Minami, H

    2015-07-28

    The influence of the structure of ionic liquids on the crystallinity of aluminum hydroxide (Al(OH)3) prepared by a sol-gel process with aluminum isopropoxide (Al(OPr(i))3) in imidazolium-based ionic liquids was investigated. When Al(OH)3 was prepared in ionic liquids having long alkyl chains, such as 1-butyl-3-methylimidazolium salts and 1-methyl-3-octylimidazolium salts, highly crystalline products were obtained. In contrast, Al(OH)3 obtained using the 1-ethyl-3-methylimidazolium salt was an amorphous material, indicating that hydrophobic interaction of the alkyl tail of the imidazolium cation of the ionic liquid strongly affects the crystallinity of sol-gel products and the local structure of the ionic liquid. Moreover, the crystallinity of Al(OH)3 prepared in ionic liquids increased relative to the amount of additional water (ionic liquid/water = 1.28/2.0-3.5/0.2, w/w). In the case of addition of a small amount of water (ionic liquid/water = 3.5/0.2, w/w), the product was amorphous. These results implied that the presence of an ionic liquid and a sufficient amount of water was crucial for the successful synthesis of sol-gel products with high crystallinity. (1)H NMR analyses revealed a shift of the peak associated with the imidazolium cation upon addition of water, which suggested that the molecular orientation of the ionic liquid was similar to that of a micelle.

  14. Effect of Preparation Parameter on Microstructure and Grain Refining Behavior of In Situ AlN-TiN-TiB2/Al Composite Inoculants on Pure Aluminum

    Directory of Open Access Journals (Sweden)

    Qian Wang

    2017-02-01

    Full Text Available The formation of in situ AlN-TiN-TiB2/Al composite inoculants, which contain multi-phase refiner particles including AlN, TiN, TiB2, Al3Ti, and α-Al, was investigated using nitrogen gas injection. The effects of the main preparation parameters such as nitriding temperature, nitriding time, Ti content in melts, on the microstructure and grain refinement of in situ AlN-TiN-TiB2/Al composite inoculants were studied. The shape, content and size of different ceramic particles in the inoculants can be tuned by controlling the nitriding temperature and time, inducing excellent refining and reinforcing effects on pure aluminum. As a result, the average grain size of pure aluminum can be reduced to about 122 ± 22 μm from original 1010 ± 80 μm by adding 0.3 wt % inoculants. The mechanical properties including the tensile strength, yield strength and microhardness of the refined as-cast pure aluminum are also improved.

  15. Optimization of process parameters of aluminum alloy AA 2014-T6 friction stir welds by response surface methodology

    Directory of Open Access Journals (Sweden)

    Ramanjaneyulu Kadaganchi

    2015-09-01

    Full Text Available The heat treatable aluminum–copper alloy AA2014 finds wide application in the aerospace and defence industry due to its high strength-to-weight ratio and good ductility. Friction stir welding (FSW process, an emerging solid state joining process, is suitable for joining this alloy compared to fusion welding processes. This work presents the formulation of a mathematical model with process parameters and tool geometry to predict the responses of friction stir welds of AA 2014-T6 aluminum alloy, viz yield strength, tensile strength and ductility. The most influential process parameters considered are spindle speed, welding speed, tilt angle and tool pin profile. A four-factor, five-level central composite design was used and a response surface methodology (RSM was employed to develop the regression models to predict the responses. The mechanical properties, such as yield strength (YS, ultimate tensile strength (UTS and percentage elongation (%El, are considered as responses. Method of analysis of variance was used to determine the important process parameters that affect the responses. Validation trials were carried out to validate these results. These results indicate that the friction stir welds of AA 2014-T6 aluminum alloy welded with hexagonal tool pin profile have the highest tensile strength and elongation, whereas the joints fabricated with conical tool pin profile have the lowest tensile strength and elongation.

  16. Microemulsion-assisted synthesis of mesoporous aluminum oxyhydroxide nanoflakes for efficient removal of gaseous formaldehyde.

    Science.gov (United States)

    Xu, Zhihua; Yu, Jiaguo; Low, Jingxiang; Jaroniec, Mietek

    2014-02-12

    Mesoporous aluminum oxyhydroxides composed of nanoflakes were prepared via a water-in-oil microemulsion-assisted hydrothermal process at 50 °C using aluminum salts as precursors and ammonium hydroxide as a precipitating agent. The microstructure, morphology, and textural properties of the as-prepared materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption, and X-ray photoelectron spectroscopy (XPS) techniques. It is shown that the aluminum oxyhydroxide nanostructures studied are effective adsorbents for removal of formaldehyde (HCHO) at ambient temperature, due to the abundance of surface hydroxyl groups, large specific surface area, and suitable pore size. Also, the type of aluminum precursor was essential for the microstructure formation and adsorption performance of the resulting materials. Namely, the sample prepared from aluminum sulfate (Al-s) exhibited a relatively high HCHO adsorption capacity in the first run, while the samples obtained from aluminum nitrate (Al-n) and chloride (Al-c) exhibited high adsorption capacity and relatively stable recyclability. A combination of high surface area and strong surface affinity of the prepared aluminum oxyhydroxide make this material a promising HCHO adsorbent for indoor air purification.

  17. A Combined Experimental and Computational Approach for the Design of Mold Topography that Leads to Desired Ingot Surface and Microstructure in Aluminum Casting.

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Zabaras, N.J.; Samanta, D.; Tan, L.

    2005-10-30

    A design methodology will be developed with which casting mold surface topographies can be tuned to produce required surface features and micro-structural properties of Aluminum ingots. Both static and continuous casting processes will be examined with instrumented molds. Mold surface topographies, which consist of unidirectional and bi-directional groove textures, will be generated using contact and non-contact techniques to elicit a radiator-like effect at the mold-casting interface. The rate of heat extraction, the evolution of near-surface cast microstructure, and shell macro-morphology can be controlled once the proper balance between mold surface area extension and the degree of imperfect wetting at the instant solidification starts is determined. Once this control is achieved, it will be possible to minimize or even eliminate costly post-casting surface milling or scalping which is currently a major barrier to the development of new Aluminum casting processes.

  18. Fabrication of aluminum foam from aluminum scrap Hamza

    Directory of Open Access Journals (Sweden)

    O. A. Osman1 ,

    2015-02-01

    Full Text Available In this study the optimum parameters affecting the preparation of aluminum foam from recycled aluminum were studied, these parameters are: temperature, CaCO3 to aluminum scrap wt. ratio as foaming agent, Al2O3 to aluminum scrap wt. ratio as thickening agent, and stirring time. The results show that, the optimum parameters are the temperature ranged from 800 to 850oC, CaCO3 to aluminum scrap wt. ratio was 5%, Al2O3 to aluminum scrap wt. ratio was 3% and stirring time was 45 second with stirring speed 1200 rpm. The produced foam apparent densities ranged from 0.40-0.60 g/cm3. The microstructure of aluminum foam was examined by using SEM, EDX and XRD, the results show that, the aluminum pores were uniformly distributed along the all matrices and the cell walls covered by thin oxide film.

  19. A New Organofunctional Ethoxysilane Self-Assembly Monolayer for Promoting Adhesion of Rubber to Aluminum

    Directory of Open Access Journals (Sweden)

    Qian Wang

    2009-10-01

    Full Text Available Practical adhesion of rubber to aluminum is measured for various aluminum silanization treatments. In this study, 6-(3-triethoxysilylpropylamino-1,3,5-triazine-2,4-dithiol (TES was used as the coupling agent for preparing self-assembly monolayers (SAMs on an aluminum surface. The structure and chemical composition of the SAMs were analyzed using Fourier transform infra-red spectroscopy (FT-IR and X-ray photoelectron spectroscopy (XPS. The changes in the surface features of the aluminum surface due to TES treatment were investigated by atomic force microscopy (AFM. The adhesive properties of the silanized aluminum surface and EPDM rubber have been evaluated by a T-peel strength test. The results suggested that the Si-O-Al bonding at aluminum TES interface existed and a TES self-assembly monolayer was formed on the aluminum surface. More than 6.0 KN/m adhesion strength is obtained when the aluminum is silanized with 2.5 mmol/dm3 TES, cured at 160 °C and vulcanized with EPDM rubber at 160 °C for 30 min. It is suggested that the TES self-assembly monolayer is bound to aluminum through its ethoxysilyl functional group, and the thiol function group is strongly crosslinked to EPDM rubber, respectively.

  20. Aluminum powder metallurgy processing

    Energy Technology Data Exchange (ETDEWEB)

    Flumerfelt, J.F.

    1999-02-12

    The objective of this dissertation is to explore the hypothesis that there is a strong linkage between gas atomization processing conditions, as-atomized aluminum powder characteristics, and the consolidation methodology required to make components from aluminum powder. The hypothesis was tested with pure aluminum powders produced by commercial air atomization, commercial inert gas atomization, and gas atomization reaction synthesis (GARS). A comparison of the GARS aluminum powders with the commercial aluminum powders showed the former to exhibit superior powder characteristics. The powders were compared in terms of size and shape, bulk chemistry, surface oxide chemistry and structure, and oxide film thickness. Minimum explosive concentration measurements assessed the dependence of explosibility hazard on surface area, oxide film thickness, and gas atomization processing conditions. The GARS aluminum powders were exposed to different relative humidity levels, demonstrating the effect of atmospheric conditions on post-atomization processing conditions. The GARS aluminum powders were exposed to different relative humidity levels, demonstrating the effect of atmospheric conditions on post-atomization oxidation of aluminum powder. An Al-Ti-Y GARS alloy exposed in ambient air at different temperatures revealed the effect of reactive alloy elements on post-atomization powder oxidation. The pure aluminum powders were consolidated by two different routes, a conventional consolidation process for fabricating aerospace components with aluminum powder and a proposed alternative. The consolidation procedures were compared by evaluating the consolidated microstructures and the corresponding mechanical properties. A low temperature solid state sintering experiment demonstrated that tap densified GARS aluminum powders can form sintering necks between contacting powder particles, unlike the total resistance to sintering of commercial air atomization aluminum powder.

  1. Surface preparation for ALD of High-k dielectrics on indium gallium arsenide

    Science.gov (United States)

    Melitz, Wilhelm

    The key for a successful gate-first process is when subsequent processing steps cannot degrade the semiconductor, the dielectric, or the oxide-semiconductor interfaces. For silicon, the only commercial ALD high-k fabrication process, which avoids processing induced damage, is a replacement gate process (a type of gate-last process). While preparing silicon for gate-last processing is straightforward, the key to a gate-last process for III-V semiconductors is the order and cleanliness of the III-V channel prior to dielectric deposition. Aggressive oxide thickness reduction (equivalent oxide thickness, or EOT, scaling) is needed to fabricate small gate length devices with small subthreshold swings. Furthermore, aggressive EOT scaling requires a very high uniform ALD nucleation density, with no pinholes due to surface contaminants. The key barrier to solving a very practical problem is a surface chemistry challenge: develop a chemical process which removes nearly all air induced defects and contaminants and leaves the III-V surface flat and electrically active for high nucleation density ALD gate oxide deposition, which unpins the Fermi level. The following study uses scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) to observe the removal of the oxide layer and restoration of the clean InGaAs surface reconstruction with atomic hydrogen cleaning, allowing for a gate-last or replacement-gate process. Along with surface cleaning STM and STS was used to characterize the initial passivation of InGaAs surfaces via ALD of trimethyl aluminum (TMA). The substrate temperature and initial surface reconstruction was critical to forming an unpinned passivation layer with a high nucleation density. A method was developed to use Kelvin probe force microscopy (KPFM) as a tool for insightful feedback on the electrostatics of scaled MOSFET devices. KPFM is a unique technique for providing two-dimensional potential profiles inside a working device. A

  2. Surface chemistry and Fermi level movement during the self-cleaning of GaAs by trimethyl-aluminum

    Science.gov (United States)

    Tallarida, M.; Adelmann, C.; Delabie, A.; Van Elshocht, S.; Caymax, M.; Schmeisser, D.

    2011-07-01

    The removal of the native oxides from NH4OH-cleaned p-GaAs (100) by exposure to trimethyl-aluminum (TMA) was studied by in situ photoelectron spectroscopy using synchrotron radiation. The reduction of high-valence As- and Ga-oxides occurred through different routes: while As3+ was reduced to As(1±Δ)+ suboxides (with 0 ≤ Δ ≤ 1), Ga3+ was directly removed. The surface Fermi level was shifted by about 100 meV towards the valence band edge upon TMA exposure. This indicates that removing the native oxide of GaAs by TMA is insufficient to create interfaces between GaAs and Al2O3 with defects densities below the 1012 cm-2 range.

  3. Microstructure, Hardness and Impact Toughness of Heat-Treated Nanodispersed Surface and Friction Stir-Processed Aluminum Alloy AA7075

    Science.gov (United States)

    Refat, M.; Elashery, A.; Toschi, S.; Ahmed, M. M. Z.; Morri, A.; El-Mahallawi, I.; Ceschini, L.

    2016-11-01

    Friction stir processing (FSP) is a recent surface engineering processing technique that is gaining wide recognition for manufacturing nanodispersed surface composites, which are of high specific strength, hardness and resistance to wear and corrosion. Herein, four-pass FSP was applied on aluminum alloy 7075 (AA7075-O) with and without the addition of alumina nanoparticles (Al2O3) of average size 40 nm. All FSP parameters were constant at 40 mm/min transverse speed, 500 rpm and tilt angle of 3°. FSP rotation direction was reversed every other pass. The friction stir-processed materials were sectioned and solution treated at 515 °C for 1.5 h, followed by age hardening at 120 °C for 12, 24, 36, 48 and 60 h. The effect of heat treatment regimes on microstructure, hardness and toughness was examined, as well as the fracture mode. The new friction stir-processed surfaces without and with nanodispersion showed enhancement in the hardness of the surface of the AA7075-O material (65 HV) to almost a double (100 and 140 HV) after four-pass FSP (before heat treatment) without and with incorporating nanoalumina particles, respectively. After 48-h aging at 120 °C, a significant enhancement in impact toughness was achieved for both the friction stir-processed without and with nanodispersion (181 and 134 J, respectively), compared to the reference material AA7075 in T6 condition (104 J).

  4. Photochemical preparation of sub-wavelength heterogeneous laser-induced periodic surface structures.

    Science.gov (United States)

    Kim, Hee-Cheol; Reinhardt, Hendrik; Hillebrecht, Pierre; Hampp, Norbert A

    2012-04-17

    Laser-induced periodic surface structures (LIPSS) are a phenomenon caused by interaction of light with solid surfaces. We present a photochemical concept which uses LIPSS-related light intensity patterns for the generation of heterogeneous nanostructures. The process facilitates arbitrary combinations of substrate and LIPSS-pattern materials. An efficient method for the generation of organometallic hybrid-nanowire arrays on porous anodic aluminum oxide is demonstrated.

  5. DETERMINATION OF OPTIMAL BALL BURNISHING PARAMETERS FOR SURFACE ROUGHNESS OF ALUMINUM ALLOY

    Directory of Open Access Journals (Sweden)

    D.B. Patel

    2013-06-01

    Full Text Available Burnishing is a cold-working process, which easily produces a smooth and work-hardened surface through the plastic deformation of surface irregularities. In the present work, the influences of the main burnishing parameters (speed, feed, force, number of tool passes, and ball diameter on the surface roughness are studied. It is found that the burnishing forces and the number of tool passes are the parameters that have the greatest effect on the workpiece surface during the burnishing process.

  6. Morphology and optical properties of aluminum oxide formed into oxalic electrolyte with addition surface active agents

    Science.gov (United States)

    Kazarkin, B.; Stsiapanau, A.; Zhilinski, V.; Chernik, A.; Bezborodov, V.; Kozak, G.; Danilovich, S.; Smirnov, A.

    2016-08-01

    The article discusses the results of investigations of porous films of alumina, formed into oxalic electrolyte with addition surface active agents, in particular, ordering structure, roughness of a surface, the optical transparency of the electrolyte concentration and surface active agents. Also discusses the features of the formation of porous films of temperature and IR radiation.

  7. Microstructure evolution and thixoforming behavior of 7075 aluminum alloy in the semi-solid state prepared by RAP method

    Science.gov (United States)

    Fu, Jin-long; Wang, Kai-kun; Li, Xiao-wei; Zhang, Hai-kuan

    2016-12-01

    The effects of isothermal treatments on the microstructural evolution and coarsening rate of semi-solid 7075 aluminum alloy produced via the recrystallization and partial remelting (RAP) process were investigated. Samples of 7075 aluminum alloy were subjected to cold extrusion, and semi-solid treatment was carried out for 5-30 min at temperatures ranging from 580 to 605°C. A backward-extrusion experiment was conducted to investigate liquid segregation during the thixoforming process. The results revealed that obvious grain coarsening and spheroidization occurred during prolonged isothermal treatments. In addition, higher soaking temperatures promoted the spheroidization and coarsening process because of the increased liquid fraction and the melting of second phases. Segregation of the liquid phase caused by the difference in fluidity between the liquid and the solid phases was observed in different regions of the thixoformed specimens.

  8. Very low surface recombination velocities on p- and n-type c-Si by ultrafast spatial atomic layer deposition of aluminum oxide

    NARCIS (Netherlands)

    Werner, F.; Veith, B.; Tiba, V.; Poodt, P.W.G.; Roozeboom, F.; Brendel, R.; Schmidt, J.

    2010-01-01

    Using aluminum oxide (Al2 O3) films deposited by high-rate spatial atomic layer deposition (ALD), we achieve very low surface recombination velocities of 6.5 cm/s on p -type and 8.1 cm/s on n -type crystalline silicon wafers. Using spatially separated reaction zones instead of

  9. Oxidation of hydrogen-passivated silicon surfaces by scanning near-field optical lithography using uncoated and aluminum-coated fiber probes

    DEFF Research Database (Denmark)

    Madsen, Steen; Bozhevolnyi, Sergey I.; Birkelund, Karen

    1997-01-01

    Optically induced oxidation of hydrogen-passivated silicon surfaces using a scanning near-field optical microscope was achieved with both uncoated and aluminum-coated fiber probes. Line scans on amorphous silicon using uncoated fiber probes display a three-peak profile after etching in potassium...

  10. Surface Characterizations of Fretting Fatigue Damage in Aluminum Alloy 7075-T6 Clamped Joints: The Beneficial Role of Ni–P Coatings

    Directory of Open Access Journals (Sweden)

    Reza H. Oskouei

    2016-02-01

    Full Text Available This paper aims to characterize the surface damage as a consequence of fretting fatigue in aluminum alloy 7075-T6 plates in double-lap bolted joints through XRD, surface profilometry, and SEM analyses. The main focus was on the surface roughness and chemical phase composition of the damaged zone along with the identification of fretting fatigue crack initiations over the surface of the material. The surface roughness of the fretted zone was found to increase when the joint was clamped with a higher tightening torque and tested under the same cyclic loading. Additionally, MgZn2 (η/ή precipitates and ZnO phase were found to form onto the surface of uncoated aluminum plate in the fretted and worn zones. The formation of the ZnO phase was understood to be a result of frictional heat induced between the surface of contacting uncoated Al 7075-T6 plates during cyclic loading and exposure to the air. The beneficial role of electroless nickel-phosphorous (Ni–P coatings in minimizing the fretting damage and thus improving the fretting fatigue life of the aluminum plates was also studied. The results showed that the surface roughness decreased by approximately 40% after applying Ni–P coatings to the Al 7075-T6 plates.

  11. CORROSION PROTECTION OF ALUMINUM

    Science.gov (United States)

    Dalrymple, R.S.; Nelson, W.B.

    1963-07-01

    Treatment of aluminum-base metal surfaces in an autoclave with an aqueous chromic acid solution of 0.5 to 3% by weight and of pH below 2 for 20 to 50 hrs at 160 to 180 deg C produces an extremely corrosion-resistant aluminum oxidechromium film on the surface. A chromic acid concentration of 1 to 2% and a pH of about 1 are preferred. (D.C.W.)

  12. The Effect Of Two-Stage Age Hardening Treatment Combined With Shot Peening On Stress Distribution In The Surface Layer Of 7075 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Kaczmarek Ł.

    2015-09-01

    Full Text Available The article present the results of the study on the improvement of mechanical properties of the surface layer of 7075 aluminum alloy via two-stage aging combined with shot peening. The experiments proved that thermo-mechanical treatment may significantly improve hardness and stress distribution in the surface layer. Compressive stresses of 226 MPa±5.5 MPa and hardness of 210±2 HV were obtained for selected samples.

  13. Anodized aluminum on LDEF

    Science.gov (United States)

    Golden, Johnny L.

    1993-01-01

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

  14. Synthesis and characterization of aluminum particles coated with uniform silica shell

    Institute of Scientific and Technical Information of China (English)

    CHENG Zhi-peng; YANG Yi; LI Feng-sheng; PAN Zhen-hua

    2008-01-01

    The silica coated aluminum composite particles were prepared by hydrolysis-condensation polymerization of tetraethylorthosilicate(TEOS) on the surface of aluminum particle. The structure, morphology, and properties of the silica coated aluminum were studied. The peaks of Si-O-Si are presented in the Fourier transform infrared (FT-IR) spectrum of the composite particles. The thickness of the silica shell is about 80 nm according to the results of transmission electron microscopy(TEM) and laser particle size analysis, while the mean diameter of the aluminum particle is 7.13 μm. The mass fraction of silica in the sample was determined by fluorescent X-ray spectrometry(XRF). Result of the thermogravimetric analysis(TGA) indicates that thermal stability of silica coated aluminum particles is better than that of pure aluminum particles at low temperature while more reactive at high temperature.

  15. Effect of co-existing ions during the preparation of alumina by electrolysis with aluminum soluble electrodes: Structure and defluoridation activity of electro-synthesized adsorbents

    Energy Technology Data Exchange (ETDEWEB)

    Tchomgui-Kamga, Eric, E-mail: etchomgui@yahoo.fr [UMR CNRS n°6226 Institut des Sciences Chimiques de Rennes, ENSCR, Avenue du Général Leclerc, CS 50837 - 35708 Rennes Cedex 7 (France); Laboratoire de Chimie Analytique, Faculté des Sciences, Université de Yaoundé-I, BP 812 Yaoundé (Cameroon); Audebrand, Nathalie, E-mail: nathalie.audebrand@univ-rennes1.fr [UMR CNRS n°6226 Institut des Sciences Chimiques de Rennes, Université de Rennes-1, Avenue du Général Leclerc, 35042 Rennes Cedex (France); Darchen, André, E-mail: Andre.Darchen@ensc-rennes.fr [UMR CNRS n°6226 Institut des Sciences Chimiques de Rennes, ENSCR, Avenue du Général Leclerc, CS 50837 - 35708 Rennes Cedex 7 (France)

    2013-06-15

    Highlights: • pH increases during electrocoagulation with aluminum electrodes are rationalized. •Composition of electrogenerated aluminas is dependent upon the electrolyte used. • All the electrogenerated aluminas contained nanoparticles of boehmite AlOOH. • The defluoridation activity of the aluminas was dependent upon the electrolyte used. -- Abstract: The electrochemical dissolution of aluminum was carried out to prepare hydrated aluminas which were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), chemical titrations and defluoridation activities. Aluminas were obtained at controlled pH depending upon the counter cations of the electrolyte. A boehmite AlOOH phase was isolated mainly in ammonium solution, while aluminas synthesized in the other media contained a mixture of phases, usually both boehmite and bayerite γ-Al(OH){sub 3}. All the boehmite phases contained nano-crystallites of less than 3 nm. Batch defluoridation experiments revealed a second influence of the original electrolyte. Aluminas were very effective in defluoridation with abatement rates of 99.5%, 98.5% and 97.3% from neutral fluoride solution at 10 mg L{sup −1} when they were prepared in solution of (NH{sub 4}){sub 2}SO{sub 4}, (NH{sub 4})HCO{sub 2} and NH{sub 4}Cl, respectively. The maximum fluoride capacities were 46.94; 10.25 and 12.18 mg g{sup −1} for aluminas prepared in solution of (NH{sub 4}){sub 2}SO{sub 4}; (NH{sub 4})HCO{sub 2} and NH{sub 4}Cl, respectively. The amount of dissolved Al was found to be less than 0.19 mg L{sup −1} at neutral pH. These results show that a defluoridation with electro-synthesized aluminas would be more efficient and safe than a direct electrocoagulation.

  16. Nature and structure of aluminum surface sites grafted on silica from a combination of high-field aluminum-27 solid-state NMR spectroscopy and first-principles calculations

    KAUST Repository

    Kerber, Rachel Nathaniel

    2012-04-18

    The determination of the nature and structure of surface sites after chemical modification of large surface area oxides such as silica is a key point for many applications and challenging from a spectroscopic point of view. This has been, for instance, a long-standing problem for silica reacted with alkylaluminum compounds, a system typically studied as a model for a supported methylaluminoxane and aluminum cocatalyst. While 27Al solid-state NMR spectroscopy would be a method of choice, it has been difficult to apply this technique because of large quadrupolar broadenings. Here, from a combined use of the highest stable field NMR instruments (17.6, 20.0, and 23.5 T) and ultrafast magic angle spinning (>60 kHz), high-quality spectra were obtained, allowing isotropic chemical shifts, quadrupolar couplings, and asymmetric parameters to be extracted. Combined with first-principles calculations, these NMR signatures were then assigned to actual structures of surface aluminum sites. For silica (here SBA-15) reacted with triethylaluminum, the surface sites are in fact mainly dinuclear Al species, grafted on the silica surface via either two terminal or two bridging siloxy ligands. Tetrahedral sites, resulting from the incorporation of Al inside the silica matrix, are also seen as minor species. No evidence for putative tri-coordinated Al atoms has been found. © 2012 American Chemical Society.

  17. A Combined Experimental and Computational Approach for the Design of Mold Topography that Leads to Desired Ingot Surface and Microstructure in Aluminum Casting.

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Zabaras, N.; Tan, L.

    2005-07-12

    A thermomechanical study of the effects of mold topography on the solidification of Aluminum alloys at early times is provided. The various coupling mechanisms between the solid-shell and mold deformation and heat transfer at the mold/solid-shell interface during the early stages of Aluminum solidification on molds with uneven topographies are investigated. The air-gap nucleation time, the stress evolution and the solid-shell growth pattern are examined for different mold topographies to illustrate the potential control of Aluminum cast surface morphologies during the early stages of solidification using proper design of mold topographies. The unstable shell growth pattern in the early solidification stages results mainly from the unevenness of the heat flux between the solid-shell and the mold surface. This heat flux is determined by the size of the air-gaps formed between the solidifying shell and mold surface or from the value of the contact pressure. Simulation results show that a sinusoidal mold surface with a smaller wavelength leads to nucleation of air-gaps at earlier times. In addition, the unevenness in the solid-shell growth pattern decreases faster for a smaller wavelength. Such studies can be used to tune mold surfaces for the control of cast surface morphologies.

  18. Negative permittivity of ZnO thin films prepared from aluminum and gallium doped ceramics via pulsed-laser deposition

    OpenAIRE

    M.A. Bodea; Sbarcea, G.; Naik, Gururaj V.; Boltasseva, Alexandra; Klar, T. A.; Pedarnig, J. D.

    2013-01-01

    Aluminum and gallium doped zinc oxide thin films with negative dielectric permittivity in the near infrared spectral range are grown by pulsed laser deposition. Composite ceramics comprising ZnO and secondary phase Al2O3 or Ga2O3 are employed as targets for laser ablation. Films deposited on glass from dense and small-grained ceramic targets show optical transmission larger than 70 % in the visible and reveal an onset of metallic reflectivity in the near infrared at 1100 nm and a crossover to...

  19. Negative permittivity of ZnO thin films prepared from aluminum and gallium doped ceramics via pulsed-laser deposition

    DEFF Research Database (Denmark)

    Bodea, M. A.; Sbarcea, G.; Naik, G. V.

    2013-01-01

    Aluminum and gallium doped zinc oxide thin films with negative dielectric permittivity in the near infrared spectral range are grown by pulsed laser deposition. Composite ceramics comprising ZnO and secondary phase Al2O3 or Ga2O3 are employed as targets for laser ablation. Films deposited on glass...... from dense and small-grained ceramic targets show optical transmission larger than 70 % in the visible and reveal an onset of metallic reflectivity in the near infrared at 1100 nm and a crossover to a negative real part of the permittivity at approximately 1500 nm. In comparison to noble metals, doped...

  20. Preparation of a PTE simulacrum based on surface molecular imprinting

    Institute of Scientific and Technical Information of China (English)

    Yong Guo; Ying Yang; Tian Ying Guo

    2011-01-01

    Firstly, we synthesized N-methacryloyl-histidine monomer and N-methacryIoyl-histidine-Cu2+ complex (MAH-Cu2+). Then the molecular imprinting polymers (MIP) has been prepared by surface grafting on uniform polystyrene (PS) core using reversible addition-fragmentation transfer polymerization (RAFT) with MAH-Cu2+ as the functional monomer, methyl paraoxon as the template to simulate phosphotriesterase (PTE). Finally, we have investigated the catalytic hydrolytic activities of MIP and non-imprinting polymers (NIP) to the template methyl paraoxon and the template analogue ethyl paraoxon respectively by UV spectrophotometry. The results showed that the catalytic hydrolytic activity of MIP to the template methyl paraoxon was highest and the value of k is 8.67 × 105 mmol L-1 min-1 3.89-fold higher than MIP to the template analogue ethyl paraoxon, 2.79-fold higher than NIP to the template methyl paraoxon. The KM, rm of MIP are also determined, and Km = 3.95 × 10-4 mol/L, rm = 2.12 μmol/ min. The MIP can be reused with only lose 7% of catalytic activity for four cycles.

  1. Bioactive carbon-PEEK composites prepared by chemical surface treatment.

    Science.gov (United States)

    Miyazaki, Toshiki; Matsunami, Chisato; Shirosaki, Yuki

    2017-01-01

    Polyetheretherketone (PEEK) has attracted much attention as an artificial intervertebral spacer for spinal reconstruction. Furthermore, PEEK plastic reinforced with carbon fiber has twice the bending strength of pure PEEK. However, the PEEK-based materials do not show ability for direct bone bonding, i.e., bioactivity. Although several trials have been conducted for enabling PEEK with bioactivity, few studies have reported on bioactive surface modification of carbon-PEEK composites. In the present study, we attempted the preparation of bioactive carbon-PEEK composites by chemical treatments with H2SO4 and CaCl2. Bioactivity was evaluated by in vitro apatite formation in simulated body fluid (SBF). The apatite formation on the carbon-PEEK composite was compared with that of pure PEEK. Both pure PEEK and carbon-PEEK composite formed the apatite in SBF when they were treated with H2SO4 and CaCl2; the latter showed higher apatite-forming ability than the former. It is conjectured that many functional groups able to induce the apatite nucleation, such as sulfo and carboxyl groups, are incorporated into the dispersed carbon phase in the carbon-PEEK composites.

  2. Spontaneous magnetization of aluminum nanowires deposited on the NaCl(100) surface

    OpenAIRE

    Ayuela, A.; Räbiger, H.; Puska, M. J.; Nieminen, R. M.

    2001-01-01

    We investigate electronic structures of Al quantum wires, both unsupported and supported on the (100) NaCl surface, using the density-functional theory. We confirm that unsupported nanowires, constrained to be linear, show magnetization when elongated beyond the equilibrium length. Allowing ions to relax, the wires deform to zig-zag structures with lower magnetization but no dimerization occurs. When an Al wire is deposited on the NaCl surface, a zig-zag geometry emerges again. The magnetizat...

  3. Preparation Method of Aluminum- plated Corrugated Cardboard and its Commercial Application%镀铝瓦楞纸板商业化应用探讨

    Institute of Scientific and Technical Information of China (English)

    周颐; 周威

    2011-01-01

    本着绿色设计低碳生产和经济的可持续发展理念,探讨真空镀铝磁控溅射镀膜理论及其技术方法制备镀铝瓦楞纸板。从而获得绿色环保的镀铝瓦楞纸板新材料。深入分析镀铝瓦楞纸板商业化应用,生产新颖、美观具有时代特点的镀铝瓦楞纸板家具,满足市场需要并获得重大的经济效益和社会效益。%According to the concept of low -carbon production and sustainable economic development, the mechanism of vacuum magnetron sputtering coating and its technology of preparing the aluminum - plated corrugated cardboard were explored in this paper in order to obtain the environment - friendly new material. Furthermore, the commercial application of aluminum - plated corrugated cardboard was analyzed to produce original elegant and fashionable furniture to meet the needs of the market and gain significant economic and social benefits.

  4. Preparation of thin hexagonal highly-ordered anodic aluminum oxide (AAO) template onto silicon substrate and growth ZnO nanorod arrays by electrodeposition

    Science.gov (United States)

    Chahrour, Khaled M.; Ahmed, Naser M.; Hashim, M. R.; Elfadill, Nezar G.; Qaeed, M. A.; Bououdina, M.

    2014-12-01

    In this study, anodic aluminum oxide (AAO) templates of Aluminum thin films onto Ti-coated silicon substrates were prepared for growth of nanostructure materials. Hexagonally highly ordered thin AAO templates were fabricated under controllable conditions by using a two-step anodization. The obtained thin AAO templates were approximately 70 nm in pore diameter and 250 nm in length with 110 nm interpore distances within an area of 3 cm2. The difference between first and second anodization was investigated in details by in situ monitoring of current-time curve. A bottom barrier layer of the AAO templates was removed during dropping the voltage in the last period of the anodization process followed by a wet etching using phosphoric acid (5 wt%) for several minutes at ambient temperature. As an application, Zn nanorod arrays embedded in anodic alumina (AAO) template were fabricated by electrodeposition. Oxygen was used to oxidize the electrodeposited Zn nanorods in the AAO template at 700 °C. The morphology, structure and photoluminescence properties of ZnO/AAO assembly were analyzed using Field-emission scanning electron microscope (FESEM), Energy dispersive X-ray spectroscopy (EDX), Atomic force microscope (AFM), X-ray diffraction (XRD) and photoluminescence (PL).

  5. 磷酸铝铬耐磨材料的制备与研究%The Preparation and Research of Wearable Material with Chrome Aluminum Phosphate Solution

    Institute of Scientific and Technical Information of China (English)

    王珏; 刘洪成; 张晓臣

    2015-01-01

    针对煤粉、热力管道高温气体冲蚀及爆管问题,以氧化铝、氧化锆、二氧化硅和磷酸铝铬溶液为主要原料,制备了一种磷酸铝铬耐磨材料,测试其剪切性能、磨耗量并观察其微观形貌。结果表明:磷酸盐基耐磨材料的室温剪切强度为3.65MPa,磨耗量为0.30g/cm2。%A kind of wearable material was prepared using aluminum oxide, zirconium dioxide, silicon dioxide and chrome aluminum phosphate solution as the main raw material for the high temperature gas erosion and burst problem on the pipeline of pulverized coal and heat power. Then we tested its shearing strength, abrasion loss and observed the microstructure. The results showed that its shear strength at room temperature was 3.65MPa, the abrasion loss was 0.30g/cm2.

  6. Preparation of Aluminum Coatings by Atmospheric Plasma Spraying and Dry-Ice Blasting and Their Corrosion Behavior

    Science.gov (United States)

    Dong, Shu-Juan; Song, Bo; Zhou, Gen-Shu; Li, Chang-Jiu; Hansz, Bernard; Liao, Han-Lin; Coddet, Christian

    2013-10-01

    Aluminum coating, as an example of spray coating material with low hardness, was deposited by atmospheric plasma spraying while dry-ice blasting was applied during the deposition process. The deposited coatings were characterized in terms of microstructure, porosity, phase composition, and the valence states. The results show that the APS aluminum coatings with dry-ice blasting present a porosity of 0.35 ± 0.02%, which is comparable to the bulk material formed by the mechanical compaction. In addition, no evident oxide has been detected, except for the very thin and impervious oxide layer at the outermost layer. Compared to plasma-sprayed Al coatings without dry-ice blasting, the adhesion increased by 52% for Al substrate using dry-ice blasting, while 25% for steel substrate. Corrosion behavior of coated samples was evaluated in 3.5 wt.% NaCl aqueous using electrochemistry measurements. The electrochemical results indicated that APS Al coating with dry-ice blasting was more resistant to pitting corrosion than the conventional plasma-sprayed Al coating.

  7. Aluminum-doped Zn O polycrystalline films prepared by co-sputtering of a Zn O-Al target

    Energy Technology Data Exchange (ETDEWEB)

    Becerril, M.; Silva L, H.; Guillen C, A.; Zelaya A, O. [Instituto Politecnico Nacional, Centro de Investigacion y de Estudios Avanzados, Departamento de Fisica, Apdo. Postal 14-740, 07000 Mexico D. F. (Mexico)

    2014-07-01

    Aluminum-doped Zinc oxide polycrystalline thin films (Azo) were grown on 7059 Corning glass substrates at room temperature by co-sputtering from a Zn O-Al target. The target was designed as follows, high purity elemental Aluminum was evaporated onto a Zn O target covering small areas. The structural, optical and electrical properties were analyzed as a function of Al content. The Al doped Zn O polycrystalline films showed an n-type conductivity. It was found that the electrical resistivity drops and the carrier concentration increases as a consequence of Al incorporation within the Zn O lattice. In both cases, the changes are of several orders of magnitude. From the results, we conclude that, using these Zn O-Al targets, n-type Al doped Zn O polycrystalline films with high transmittance and low resistivity can be obtained. The crystalline structure of the films was determined by X-ray diffraction. Atomic Force Microscopy images were obtained with an Auto probe C P (Veeco Metrology Group) Microscope. (Author)

  8. Study of Internal Channel Surface Roughnesses Manufactured by Selective Laser Melting in Aluminum and Titanium Alloys

    Science.gov (United States)

    Pakkanen, Jukka; Calignano, Flaviana; Trevisan, Francesco; Lorusso, Massimo; Ambrosio, Elisa Paola; Manfredi, Diego; Fino, Paolo

    2016-08-01

    Interest in additive manufacturing (AM) has gained considerable impetus over the past decade. One of the driving factors for AM success is the ability to create unique designs with intrinsic characteristics as, e.g., internal channels used for hydraulic components, cooling channels, and heat exchangers. However, a couple of the main problems in internal channels manufactured by AM technologies are the high surface roughness obtained and the distortion of the channel shape. There is still much to understand in these design aspects. In this study, a cylindrical geometry for internal channels to be built with different angles with respect to the building plane in AlSi10Mg and Ti6Al4V alloys by selective laser melting was considered. The internal surfaces of the channels produced in both materials were analyzed by means of a surface roughness tester and by optical and electron microscopy to evaluate the effects of the material and design choices.

  9. Control and Prevention of Ice Formation on the Surface of an Aluminum Alloy

    DEFF Research Database (Denmark)

    Rahimi, Maral

    In cold climates, mechanical ventilation systems with heat recovery, e.g. air-to-air exchangers, are often used to reduce energy demand for heating by recovering the heat from the exhausted air. This, however, creates a risk of ice accretion on the fins of the heat exchanger as warm and humid...... modified with (3-aminopropyl) triethoxy silane (APTES) exhibited longer freezing delays as compared to both more hydrophilic and more hydrophobic substrates. This is attributed to a particular surface chemistry of the APTES modification that prevents ice formation at the interface of the substrate due...... to presence of high local ion concentration (amino groups), hence leading to significant freezing point suppression. Furthermore, the results suggest that surface topography and wettability determine the freezing kinetics of a droplet placed on a precooled sample. Therefore, surface chemistry which may change...

  10. Temperature-dependent 780-nm laser absorption by engineering grade aluminum, titanium, and steel alloy surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Rubenchik, Alexander M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wu, Sheldon S. Q. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kanz, V. Keith [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); LeBlanc, Mary M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lowdermilk, W. Howard [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Rotter, Mark D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Stanley, Joel R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-07-17

    When modeling laser interaction with metals for various applications it requires a knowledge of absorption coefficients for real, commercially available materials with engineering grade (unpolished, oxidized) surfaces. But, most currently available absorptivity data pertain to pure metals with polished surfaces or vacuum-deposited thin films in controlled atmospheres. A simple laboratory setup is developed for the direct calorimetric absorptivity measurements using a diode-array laser emitting at 780 nm. A scheme eliminating the effect of convective and radiative losses is implemented. Futhermore, the obtained absorptivity results differ considerably from existing data for polished pure metals and are essential for the development of predictive laser-material interaction models.

  11. Aluminum-contaminant transport by surface runoff and bypass flow from an acid sulphate soil

    NARCIS (Netherlands)

    Minh, L.Q.; Tuong, T.P.; Mensvoort, van M.E.F.; Bouma, J.

    2002-01-01

    Quantifying the process and the amount of acid-contaminant released to the surroundings is important in assessing the environmental hazards associated with reclaiming acid sulphate soils (ASS). The roles of surface runoff and bypass flow (i.e. the rapid downward flow of free water along macropores t

  12. Aluminum-contaminant transport by surface runoff and bypass flow from an acid sulphate soil

    NARCIS (Netherlands)

    Minh, L.Q.; Tuong, T.P.; Mensvoort, van M.E.F.; Bouma, J.

    2002-01-01

    Quantifying the process and the amount of acid-contaminant released to the surroundings is important in assessing the environmental hazards associated with reclaiming acid sulphate soils (ASS). The roles of surface runoff and bypass flow (i.e. the rapid downward flow of free water along macropores t

  13. Aluminum and phosphorus separation: application to preparation of target from brain tissue for {sup 26}Al determination by accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Brauer, Russell D.; Robertson, J. David; Sharma, Pankaj; Yokel, Robert A. E-mail: ryokel1@pop.uky.edu

    1999-04-01

    Acid digested brain containing 4 mg added {sup 27}Al was ashed at 1000 deg. C to prepare an Al{sub 2}O{sub 3} target for accelerator mass spectrometry (AMS) analysis of {sup 26}Al. A glass-like material usually resulted which was thought to be aluminum (Al) oxyphosphate. The separation of Al and phosphate was investigated. Al, but not phosphate, was bound by a cation exchange resin (AG 50-X8). Hydrofluoric acid eluted the Al from the resin. Removal of phosphate from acid digested brain by this method produced an amorphous material after ashing that was easier to recover from the porcelain crucible and had a higher AMS beam current. This procedure to separate Al from phosphate may have utility in other applications.

  14. Effect of Si3N4 powder reactivity on the preparation of the Si2N2O-Al2O3 silicon aluminum oxynitride solid solution

    Science.gov (United States)

    Sekercioglu, I.; Wills, R. R.

    1979-01-01

    Dense high-purity silicon aluminum oxynitride was prepared by reactive hot-pressing of an Si3N4-Al2O3-SiO2 mixture. The formation of a single-phase material was found to be critically dependent on the Si3N4 powder in the starting mixture. It is suggested that evolution of a chlorine- and nitrogen-containing species may enhance the reactivity of Si3N4 in this reaction. Densities of O prime sialons are very similar to that of Si2N2O, the widely quoted value in the ceramics literature of 3.1 g/cu cm for the density of Si2N2O being incorrect.

  15. Effect of oxidation time on the microstructure and properties of ceramic coatings prepared by microarc oxidation on 7A04 superhard aluminum alloy

    Science.gov (United States)

    Xiao, Feng; Chen, Hui; Miao, Jingguo; Du, Juan

    2017-07-01

    Under the sodium aluminates’ system, microarc oxidation treatment was conducted on the superhard aluminum alloy 7A04 for different times. The microstructure of microarc oxidation ceramic layer was investigated by using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The influences of different oxidation times on the adhesion strength of ceramic layer and substrate, the morphology of surface and cross-section, the phase composition and the electrochemical properties were studied. The results indicated that the connection of the coating and substrate appears to be metallurgical bonding and dense ceramic layer, and the surface is in a “volcanic vent” morphology, which is composed of γ-Al2O3 and little α-Al2O3. The corrosion resistance of ceramic layer is improved significantly in contrast with that of the substrate.

  16. Interactions of satellite-speed helium atoms with satellite surfaces. III. Drag coefficients from spatial and energy distributions of reflected helium atoms. [1235-O and 6061 T-6 aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, P.K.; Knuth, E.L.

    1977-12-01

    Spatial and energy distributions of helium atoms scattered from an anodized 1235-0 aluminum surface as well as the tangential and normal momentum accommodation coefficients calculated from these distributions are reported. A procedure for calculating drag coefficients from measured values of spatial and energy distributions is given. The drag coefficient calculated for a 6061 T-6 aluminum sphere is included.

  17. 铝锅表面导磁处理工艺%Surface treatment for making electromagnetic induction aluminum cooker

    Institute of Scientific and Technical Information of China (English)

    雷大法

    2014-01-01

    介绍了一种能使铝锅具备导磁性能的表面处理工艺。首先对铝锅进行喷砂处理,使其外表面的粗糙度Ra达到2.5~5.0μm,再电弧喷涂一层可导磁的铁涂层,并对铁层进行砂光处理,最后喷涂高温有机硅树脂保护涂层。经测试,铁涂层平均膜厚为207μm,表面孔隙率为1.28%,平均断裂载荷为21109.48 N,平均断裂强度为41.66 MPa;有机硅涂层的附着力、耐溶剂性、耐热性良好。最终产品的导磁性能达到企业标准。%A surface treatment, which enables aluminum cooker get electromagnetic induction, was introduced. The process mainly includes: sandblasting to achieve a surface roughness Ra of 2.5-5.0μm, electric arc spraying to form an iron coating, polishing, and spraying with a high-temperature silicone resin coating. The test results showed that the iron coating has the following properties:average thickness 207μm, surface porosity 1.28%, average breaking load 21 109.48 N, and average fracture strength 41.66 MPa. The organic silicon coating has good adhesion strength, solvent resistance, and thermal resistance. The electromagnetic induction performance of the cooker meets the enterprise standard.

  18. Study of the processes of adsorption of amine-containing surface-active substance on the surface of Aluminum powder

    Directory of Open Access Journals (Sweden)

    Antonina Dyuryagina

    2012-03-01

    Full Text Available Equilibrium characteristics of adsorption on a surface of a pigment depending on concentration factors and temperature of the dispersive environment are defined. Kinetic laws of superficial activity of binary, threefold homogeneous and heterogeneous modeling systems are studied. The estimation of mechanisms of process of adsorption is carried out.

  19. Clinical biochemistry of aluminum

    Energy Technology Data Exchange (ETDEWEB)

    King, S.W.; Savory, J.; Wills, M.R.

    1981-05-01

    Aluminum toxicity has been implicated in the pathogenesis of a number of clinical disorders in patients with chronic renal failure on long-term intermittent hemodialysis treatment. The predominant disorders have been those involving either bone (osteomalacic dialysis osteodystrophy) or brain (dialysis encephalopathy). In nonuremic patients, an increased brain aluminum concentration has been implicated as a neurotoxic agent in the pathogenesis of Alzheimer's disease and was associated with experimental neurofibrillary degeneration in animals. The brain aluminum concentrations of patients dying with the syndrome of dialysis encephalopathy (dialysis dementia) are significantly higher than in dialyzed patients without the syndrome and in nondialyzed patients. Two potential sources for the increased tissue content of aluminum in patients on hemodialysis have been proposed: (1) intestinal absorption from aluminum containing phosphate-binding gels, and (2) transfer across the dialysis membrane from aluminum in the water used to prepare the dialysate. These findings, coupled with our everyday exposure to the ubiquitous occurrence of aluminum in nature, have created concerns over the potential toxicity of this metal.

  20. Control of surface defects on plasma-MIG hybrid welds in cryogenic aluminum alloys

    Directory of Open Access Journals (Sweden)

    Lee Hee-Keun

    2015-07-01

    Full Text Available Lately, high production rate welding processes for Al alloys, which are used as LNG FPSO cargo containment system material, have been developed to overcome the limit of installation and high rework rates. In particular, plasma-metal inert gas (MIG hybrid (PMH welding can be used to obtain a higher deposition rate and lower porosity, while facilitating a cleaning effect by preheating and post heating the wire and the base metal. However, an asymmetric undercut and a black-colored deposit are created on the surface of PMH weld in Al alloys. For controlling the surface defect formation, the wire feeding speed and nozzle diameter in the PMH weld was investigated through arc phenomena with high-speed imaging and metallurgical analysis.

  1. Imaging and Information Processing of Pitting-Corroded Aluminum Alloy Panels with Surface Metrology Methods

    Science.gov (United States)

    2014-12-23

    is the Senior Systems Engineer for Analatom, Inc. He received the bachelor of science degree in electrical engineering from the Rochester...Jiaming Li 3 , Javier Echauz 4 , Douglas Brown 5 , George J. Vachtsevanos 6 1, 2, 3, 6 Department of Electrical and Computer Engineering, Georgia...measurement covers a broad spectrum of technical approaches including acoustic, electrical and chemical methods. Surface metrology is an

  2. The formation and structure of the oxide and hydroxide chemisorbed phases at the aluminum surface, and relevance to hydrogen embrittlement

    Science.gov (United States)

    Francis, Michael; Kelly, Robert; Neurock, Matthew

    2010-03-01

    Aluminum alloys used in aerospace structures are susceptible to environmentally assisted cracking (EAC) induced by hydrogen embrittlement (HE) (Gangloff and Ives 1990). Crack growth experiments have demonstrated a linear relation between the relative humidity of the environment and crack growth rates, indicating the importance of water (Speidel and Hyatt 1972). While the presence of water has been demonstrated to be necessary for EAC of aluminum, crack growth rates have been linked to the diffusivity of hydrogen in aluminum (Gangloff 2003) and hydrogen densities at the crack tip as high as Al2H have been observed (Young and Scully 1998). While the mechanism by which hydrogen embrittles aluminum is yet not well understood, without the entry of hydrogen into the aluminum matrix, embrittlement would not occur. While at the crack tip high hydrogen concentrations exist, the solubility of hydrogen in aluminum is normal near 1 ppm (Wolverton 2004). In this work combined first principles and kinetic Monte Carlo methods will be used to examine the oxide and hydroxide structure resulting from exposure of aluminum to H2O or O2 and relevance to hydrogen entry as well as EAC is discussed.

  3. Optimization of the FeCo nanowire fabrication embedded in anodic aluminum oxide template by response surface methodology

    Directory of Open Access Journals (Sweden)

    Mina Salehi

    2014-06-01

    Full Text Available Anodic aluminum oxide (AAO fabricated by two step anodization technique, is used as a template to synthesize FeCo nanowire arrays by AC electrodeposition technique. Response surface methodology (RSM is applied to design the experiments, fit an empirical model and optimize the conditions to achieve the best magnetic properties. The magnetic properties, pore dimensions, composition and structure of the nanowires are characterized through alternating gradient force magnetometer (AGFM, scanning electron microscopy (SEM, scanning probe microscopy (SPM, energy dispersive spectoroscopy (EDS and X-ray diffraction (XRD, respectively. The effects of annealing temperature (Ta, Fe concentration (C, the pH of the deposition solution (pH and electrodeposition temperature (Td on the magnetic properties are investigated. Maximum experimental coercivity field (Hc = 191.4 KA/m is obtained in the following conditions: Ta = 550 °C; C = 50 wt%; pH = 6; Td = 40 °C. The optimum values to obtain maximum predicted coercivity field (Hc = 195.5 KA/m are predicted with a statistical technique as: Ta = 575 °C; C = 50.3 wt%; pH = 6; Td = 39 °C. Moreover, the results show that Td2 and Ta are the most important parameters affecting coercivity field. XRD results show that the crystal structure of nanowires is BCC with (1 1 0 preferred orientation along the nanowire axis.

  4. Very low surface recombination velocity on p-type c-Si by high-rate plasma-deposited aluminum oxide

    Science.gov (United States)

    Saint-Cast, Pierre; Kania, Daniel; Hofmann, Marc; Benick, Jan; Rentsch, Jochen; Preu, Ralf

    2009-10-01

    Aluminum oxide layers can provide excellent passivation for lowly and highly doped p-type silicon surfaces. Fixed negative charges induce an accumulation layer at the p-type silicon interface, resulting in very effective field-effect passivation. This paper presents highly negatively charged (Qox=-2.1×1012 cm-2) aluminum oxide layers produced using an inline plasma-enhanced chemical vapor deposition system, leading to very low effective recombination velocities (˜10 cm s-1) on low-resistivity p-type substrates. A minimum static deposition rate (100 nm min-1) at least one order of magnitude higher than atomic layer deposition was achieved on a large carrier surfaces (˜1 m2) without significantly reducing the resultant passivation quality.

  5. Surface study of gallium- and aluminum- doped graphenes upon adsorption of cytosine: DFT calculations

    Science.gov (United States)

    Shokuhi Rad, Ali; Zareyee, Daryoush; Peyravi, Majid; Jahanshahi, Mohsen

    2016-12-01

    The adsorption of cytosine molecule on Al- and Ga- doped graphenes is studied using first-principles density functional theory (DFT) calculations. The energetically most stable geometries of cytosine on both Al- and Ga- doped graphenes are determined and the adsorption energies are calculated. The net charge of transfer as well as local charge of doped atoms upon adsorption of cytosine are studied by natural bond orbitals (NBO) analysis. Orbital hybridizing of complexes was searched by frontier molecular orbital theory (FMO), and density of states (DOS). Depending on the side of cytosine, there are four possible sites for its adsorption on doped graphene; denoted as P1, P2, P3, and P4, respectively. The order of binding energy in the case of Al-doped graphene is found as P1 ˃ P4 ˃ P3 ˃ P2. Interestingly, the order in the case of Ga-doped graphene changes to: P4 ∼ P1˃ P3˃ P2. Both surfaces show superior adsorbent property, resulting chemisorption of cytosine, especially at P1 and P4 position configurations. The NBO charge analysis reveals that the charge transfers from Al- and Ga- doped graphene sheets to cytosine. The electronic properties of both surfaces undertake important changes after cytosine adsorption, which indicates notable change in its electrical conductivity.

  6. Bactericidal Effect of Erbium-Doped Yttrium Aluminum Garnet Laser and Photodynamic Therapy on Aggregatibacter Actinomycetemcomitans Biofilm on Implant Surface.

    Science.gov (United States)

    Saffarpour, Anna; Fekrazad, Reza; Heibati, Maryam Naghavi; Bahador, Abbas; Saffarpour, Aida; Rokn, Amir R; Iranparvar, Aysel; KharaziFard, Mohammad J

    2016-01-01

    Peri-implantitis is a common complication of dental implants. The first step of treatment is elimination of bacterial biofilm and disinfection of the implant surface. This study sought to compare the effects of an erbium-doped yttrium aluminum garnet (Er:YAG) laser, photodynamic therapy using an indocyanin green-based photosensitizer (ICG-based PS) and diode laser, toluidine blue O (TBO) photosensitizer and light-emitting diode (LED) light source, and 2% chlorhexidine (CHX) on biofilm of Aggregatibacter actinomycetemcomitans to sandblasted, large-grit, acid-etched (SLA) implant surfaces. Fifty SLA implants were divided into five groups and were incubated with A actinomycetemcomitans bacteria to form bacterial biofilm. Group 1 underwent Er:YAG laser radiation (with 10-Hz frequency, 100-mJ energy, and 1-W power); group 2 was subjected to LED (with 630-nm wavelength and maximum output intensity of 2.000 to 4.000 mW/cm(2)) and TBO as a photosensitizer; group 3 was exposed to diode laser radiation (with 810-nm wavelength and 300-mW power) and ICG-based PS; and group 4 was immersed in 2% CHX. Group 5 was the control group, and the samples were rinsed with normal saline. The number of colony-forming units (CFU) per implant was then calculated. Data were analyzed using one-way analysis of variance (ANOVA), and the five groups were compared. Significant differences was found between the control group and the other groups (P laser was more effective than Er:YAG laser irradiation in suppression of this organism (P < .01). There was no significant difference between groups 2 and 3. The antibacterial effect of 2% CHX was greater than that of other understudy methods.

  7. Double catholyte electrochemical approach for preparing ferrate-aluminum: a compound dxidant-coagulant for water purification

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Ferrate is an excellent water treatment agent for its multi-functions in oxidation, disinfection, coagulation and adsorption, but its coagulation ability depends on its dosage and is after its oxidation. This paper focuses on preparing a new kind of ferrate combined with alum to enhance its coagulation function for water purification. An effective electrolysis reactor was designed and employed in the test. Some key parameters in the process of electrolysis concerning the preparation efficiency, such as the current density, temperature and alkalinity were also investigated. The proper conditions for ferrate-alum preparation were determined. In the condition of 5V given voltage, 6h electrolyzing interval, below 2% alum concentration (in weight), a combined liquid ferrate-alum products was successfully prepared, which contained 0.0294 mol/L FeO42-, 0.0302 mol/L total soluble ferron with 2% Al2O3. There was no insoluble ferron produced by controlling an optimum electrochemical condition.

  8. Observation of multiple-harmonic radiation induced from a gold surface by picosecond neodymium-doped yttrium aluminum garnet laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Farkas, G.; Toth, C. (Research Institute for Solid-State Physics, P.O. Box 49, H-1525 Budapest (Hungary)); Moustaizis, S.D.; Papadogiannis, N.A.; Fotakis, C. (Foundation for Research and Technology, Hellas, P.O. Box 1527, Heraklion 711 10, Crete (Greece))

    1992-10-01

    Illuminating a gold surface by strong (5 GW/cm{sup 2}) picosecond neodymium-doped yttrium aluminum garnet laser pulses at grazing incidence, we observed a generation of coherent beams of both even and odd harmonics up to fifth order in the reflected direction with efficiencies 10{sup {minus}10--}10{sup {minus}13}. The observed decrease of the harmonic efficiencies with increasing harmonic order is much weaker than predicted by perturbative theories.

  9. The Surface Structure and Thermal Properties of Novel Polymer Composite Films Based on Partially Phosphorylated Poly(vinyl alcohol with Aluminum Phosphate

    Directory of Open Access Journals (Sweden)

    Asmalina Mohamed Saat

    2014-01-01

    Full Text Available Partially phosphorylated polyvinyl alcohol (PPVA with aluminum phosphate (ALPO4 composites was synthesized by solution casting technique to produce (PPVA100-y-(ALPO4y (y = 0, 1, and 2. The surface structure and thermal properties of the films were characterized using Fourier transform infrared (FTIR spectroscopy and thermogravimetric analysis (TGA. The results showed that the films have higher thermal stability with strong bonding between PPVA and ALPO4.

  10. XPS and FTIR investigation of the surface properties of different prepared titania nano-powders

    DEFF Research Database (Denmark)

    Jensen, Henrik; Solovyev, Alexey; Lie, Zheshen

    2005-01-01

    oxygen (29%) and sol–gel prepared powder showed the greatest amount of surface oxygen (66%) in the form of surface hydroxyl groups. The remaining oxygen was identified as lattice oxygen. The powder prepared by the sol–gel method contained carbon impurities originating from residual alkoxy groups....... Supercritical sol–gel prepared powder and powder prepared by the sulphate method revealed same trends regarding oxygen composition with 44–47% being surface oxygen; neither contained carbon impurities. The results obtained from XPS were confirmed by FTIR measurements....

  11. Thick and hard anodized aluminum film with large pores for surface composites

    Institute of Scientific and Technical Information of China (English)

    WANG Hui; WANG Hao-wei

    2004-01-01

    Al-base surface self-lubricating composites need thick and hard alumina membranes with large pores to add lubricants easily. This kind of porous alumina layer was fabricated in additive-containing, phosphoric acid-based solution. The effects of additive containing organic carboxylic acid and Ce salt on the properties of the oxide film and mechanism were investigated in detail with SEM and EDAX analyses. The results show that the pore diameter is about 100 nm, the film thickness increases by 4 -5 times, and the Vickers hardness improves by about 50% through adding some amount of organic carboxylic acid and Ce salt. Such an improvement in properties is explained in terms of a lower film dissolving velocity and better film quality in compound solution.

  12. Surface morphology of titanium dioxide (TiO2) nanoparticles on aluminum interdigitated device electrodes (IDEs)

    Science.gov (United States)

    Azizah, N.; Hashim, U.; Arshad, M. K. Md.; Gopinath, Subash C. B.; Nadzirah, Sh.; Farehanim, M. A.; Fatin, M. F.; Ruslinda, A. R.; Ayub, R. M.

    2016-07-01

    Titanium dioxide (TiO2) nanoparticles based Interdigitated Device Electrodes (IDEs) Nanobiosensor device was developed for intracellular biochemical detection. Fabrication and characterization of Scanning Electron Microscopy (SEM) using IDE nanocoated with TiO2 was studied in this paper. SEM analysis was carried out at 10 kV acceleration volatege and a 9.8 mA emission current to compare IDE with and without TiO2 on the surface area. The simple fabrication process, high sensitivity, and fast response of the TiO2 based IDEs facilitate their applications in a wide range of areas. The small size of semiconductor TiO2 based IDE for sensitive, label-free, real time detection of a wide range of biological species could be explored in vivo diagnostics and array-based screening.

  13. Electronic and Optical Properties of Aluminum Oxide Before and After Surface Reduction by Ar+ Bombardment

    Directory of Open Access Journals (Sweden)

    D. Tahir

    2014-08-01

    Full Text Available The electronic and optical properties of a-Al2O3 after induced by 3-keV Ar+ sputtering have been studied quantitatively by use of reflection electron energy loss spectroscopy (REELS spectra. The band gap values of a-Al2O3 was determined from the onset values of the energy loss spectrum to the background level of REELS spectra as a function of time Ar+ bombardment. The bandgap changes from 8.4 eV before sputtering to 6.2 eV after 4 minutes of sputtering.The optical properties of α-Al2O3 thin films have been determined by comparing the experimental cross section obtained from reflection electron energy loss spectroscopy with the theoretical inelastic scattering cross section, deduced from the simulated energy loss function (ELF by using QUEELS-ε(k-REELS software. The peak assignments are based on ELF and compared with reported data on the electronic structure of α-Al2O3 obtained using different techniques. The results demonstrate that the electronic and optical properties before and after surface reduction will provide further understanding in the fundamental properties of α-Al2O3 which will be useful in the design, modeling and analysis of devices applications performance.

  14. Modeling of burr size in drilling of aluminum silicon carbide composites using response surface methodology

    Directory of Open Access Journals (Sweden)

    Avinash A. Thakre

    2016-09-01

    Full Text Available Exit burrs produced during various machining processes degrade the product quality and functionality of different parts of assembly. It is essential to select the optimum tool geometry and process parameters for minimizing the burr formation during machining. In this paper, the effects of cutting speed, feed rate, point angle of drill bits and concentration of the reinforcements on the burrs produced were investigated. Response surface methodology has been adopted to create the quadratic model for the height and thickness of the burrs produced during drilling of AlSiC composites. Analysis of means and variance were used to find the significance of the process parameters on the responses and to find the optimum combination of parameters to minimize the burr formation. Feed rate, point angle and concentration of reinforcements in the matrix are found to be the significant factors. Both the responses were found to be minimum for lower feed rate, higher point angle and higher concentration of reinforcements. Scanning electron microscopy was used to understand the mechanism of burr formation.

  15. Local charge exchange of He{sup +} ions at Aluminum surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Riccardi, P., E-mail: pierfrancesco.riccardi@fis.unical.it [Dipartimento di Fisica, Università della Calabria and INFN – Gruppo collegato di Cosenza, Via P. Bucci cubo 33C, Arcavacata di Rende, Cosenza (Italy); Sindona, A. [Dipartimento di Fisica, Università della Calabria and INFN – Gruppo collegato di Cosenza, Via P. Bucci cubo 33C, Arcavacata di Rende, Cosenza (Italy); Dukes, C.A. [Laboratory for Astrophysics and Surface Physics, Materials Science and Engineering University of Virginia, Charlottesville, VA 22904 (United States)

    2017-04-04

    We report on experiments designed to observe the correlation between the autoionization of doubly excited helium atoms and the Auger decay of 2p vacancies in Al. The autoionizing states are formed when incident He{sup +*} and He{sup ++} are neutralized by resonant electron capture at the surface. 2p excitation in Al occurs in dielectronic charge transfer during the close encounter of an excited helium ion and an Al atom. These results clarify the mechanism for Al-2p excitation in the case of singly charged ground state He{sup +}(1s) ion impact, where the dielectronic transition occurs after promotion of the 1s electron of incoming ions. - Highlights: • We observe the correlation between autoionization of doubly excited helium atoms and the Auger decay of 2p vacancies in Al. • 2p excitation in Al occurs in dielectronic charge transfer during the close encounter of an excited helium ion and an Al atom. • These results clarify the mechanism for Al-2p excitation in the case of singly charged ground state He{sup +}(1s) ion impact.

  16. Method for Aluminum Oxide Thin Films Prepared through Low Temperature Atomic Layer Deposition for Encapsulating Organic Electroluminescent Devices

    Directory of Open Access Journals (Sweden)

    Hui-Ying Li

    2015-02-01

    Full Text Available Preparation of dense alumina (Al2O3 thin film through atomic layer deposition (ALD provides a pathway to achieve the encapsulation of organic light emitting devices (OLED. Unlike traditional ALD which is usually executed at higher reaction n temperatures that may affect the performance of OLED, this application discusses the development on preparation of ALD thin film at a low temperature. One concern of ALD is the suppressing effect of ambient temperature on uniformity of thin film. To mitigate this issue, the pumping time in each reaction cycle was increased during the preparation process, which removed reaction byproducts and inhibited the formation of vacancies. As a result, the obtained thin film had both high uniformity and density properties, which provided an excellent encapsulation performance. The results from microstructure morphology analysis, water vapor transmission rate, and lifetime test showed that the difference in uniformity between thin films prepared at low temperatures, with increased pumping time, and high temperatures was small and there was no obvious influence of increased pumping time on light emitting performance. Meanwhile, the permeability for water vapor of the thin film prepared at a low temperature was found to reach as low as 1.5 × 10−4 g/(m2·day under ambient conditions of 25 °C and 60% relative humidity, indicating a potential extension in the lifetime for the OLED.

  17. Removal of fluoride from drinking water using aluminum hydroxide coated activated carbon prepared from bark of Morinda tinctoria

    Science.gov (United States)

    Amalraj, Augustine; Pius, Anitha

    2016-10-01

    The aim of this study is to design and develop a novel cost effective method for fluoride removal, applicable to rural areas of developing countries. Adsorption is widely considered as one of the appropriate technologies for water defluoridation. This study investigates the feasibility of using low-cost biomass based activated carbon from the bark of Morinda tinctoria coated with aluminum hydroxide (AHAC) for water defluoridation, at neutral pH range. Characterization of AHAC was done through IR, SEM with EDAX studies before and after fluoride treatment. The fluoride adsorption capacity of AHAC as a function of contact time, pH and initial fluoride concentration was investigated. The role of co-existing interfering ions also was studied. The isotherm and kinetic models were used to understand the nature of the fluoride adsorption onto AHAC. Freundlich isotherm and intra-particle diffusion were the best-fitting models for the adsorption of fluoride on AHAC. Fluoride adsorption kinetics well fitted with pseudo-second order model. The results showed excellent fluoride adsorption capacity was found to be 26.03 mg g-1 at neutral pH.

  18. Microstructure and properties of mechanical alloying particles reinforced aluminum matrix composites prepared by semisolid stirring pouring method

    Directory of Open Access Journals (Sweden)

    Yao-qiang Si

    2016-05-01

    Full Text Available Aluminum matrix composites reinforced with mechanical alloying particles (SiCp were fabricated by the semisolid stirring pouring method. The influence of mechanical alloying particles and Mg on the microstructure and mechanical properties of the composites was investigated by means of optical microscopy (OM, X-ray diffraction scanning (XRD, electron microscopy (SEM and energy dispersive spectroscopy (EDS. Results show that the addition of Mg converts the agglomerate mechanical alloying particles in ZL101 matrix composites into dispersed distribution in ZL101-Mg matrix composites, large matrix grains into fine equiaxed matrix grains, and eutectic phase into fine particles. So the mechanical properties of ZL101-Mg matrix composites are better than those of ZL101 matrix composites. The mechanical properties of ZL101/ZL101-Mg matrix composites are gradually increased with the increase of the volume fraction of mechanical alloying particles. When the volume fraction of mechanical alloying particles is 3%, the Vickers hardness and ultimate tensile strength of the ZL101/ZL101-Mg matrix composites reach their maximum values.

  19. Contamination and Surface Preparation Effects on Composite Bonding

    Science.gov (United States)

    Kutscha, Eileen O.; Vahey, Paul G.; Belcher, Marcus A.; VanVoast, Peter J.; Grace, William B.; Blohowiak, Kay Y.; Palmieri, Frank L.; Connell, John W.

    2017-01-01

    Results presented here demonstrate the effect of several prebond surface contaminants (hydrocarbon, machining fluid, latex, silicone, peel ply residue, release film) on bond quality, as measured by fracture toughness and failure modes of carbon fiber reinforced epoxy substrates bonded in secondary and co-bond configurations with paste and film adhesives. Additionally, the capability of various prebond surface property measurement tools to detect contaminants and potentially predict subsequent bond performance of three different adhesives is also shown. Surface measurement methods included water contact angle, Dyne solution wettability, optically stimulated electron emission spectroscopy, surface free energy, inverse gas chromatography, and Fourier transform infrared spectroscopy with chemometrics analysis. Information will also be provided on the effectiveness of mechanical and energetic surface treatments to recover a bondable surface after contamination. The benefits and drawbacks of the various surface analysis tools to detect contaminants and evaluate prebond surfaces after surface treatment were assessed as well as their ability to correlate to bond performance. Surface analysis tools were also evaluated for their potential use as in-line quality control of adhesive bonding parameters in the manufacturing environment.

  20. Preparation Of Control Space For Remeshing Of Polygonal Surfaces

    OpenAIRE

    Tomasz Jurczyk; Barbara Glut

    2013-01-01

    The subject of the article concerns the issues of remeshing, transforming a polygonal mesh into a triangular mesh adapted to surface. From the initial polygonal mesh the curvature of surface and boundary is retrieved and used to calculate a metric tensor varying in three-dimensional space. In the proposed approach the curvature is computed using local approximation of surfaces and curves on the basis of vertices of the polygonal mesh. An essential part of the presented remeshing procedure is...

  1. Energy transferred to the substrate surface during reactive magnetron sputtering of aluminum in Ar/O{sub 2} atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Thomann, A.L., E-mail: anne-lise.thomann@univ-orleans.fr [GREMI, UMR 7344 du CNRS et de l' Université d' Orléans, 14 rue d' Issoudun, B.P. 6744, 45067 Orléans Cedex 2 (France); Cormier, P.A. [GREMI, UMR 7344 du CNRS et de l' Université d' Orléans, 14 rue d' Issoudun, B.P. 6744, 45067 Orléans Cedex 2 (France); Dolique, V. [LMA, Université Claude Bernard Lyon I, Campus de la DOUA, Bâtiment Virgo 7 Avenue Pierre de Coubertin, 69622 Villeurbanne Cedex (France); Semmar, N.; Dussart, R.; Lecas, T. [GREMI, UMR 7344 du CNRS et de l' Université d' Orléans, 14 rue d' Issoudun, B.P. 6744, 45067 Orléans Cedex 2 (France); Courtois, B. [CEMHTI, UPR3079 du CNRS, 1D Avenue de la Recherche Scientifique, 45071 Orléans Cedex 2 (France); Brault, P. [GREMI, UMR 7344 du CNRS et de l' Université d' Orléans, 14 rue d' Issoudun, B.P. 6744, 45067 Orléans Cedex 2 (France)

    2013-07-31

    A study of the reactive sputtering of aluminum was carried out by coupling energy flux measurements at the substrate location with conventional diagnostics of the gas phase and analyses of the deposited films. The main purpose was to get some insight into the elementary mechanisms involved at the substrate surface during the film growth in the well known metal and oxide regimes and at the transitions from one to another. Measurements were carried out in front of a 10 cm Al target at a power of 400 W (i.e. 5 W/cm{sup 2}) and a total pressure of 0.6 Pa. The flow rate ratio (O{sub 2}/O{sub 2} + Ar) was varied in the range 0 to 50%. Different kinetics and values of energy transfer, denoting different involved mechanisms, were evidenced at metal-oxide (increasing flow rate) and oxide-metal (decreasing flow rate) transitions. The metal-oxide transition was found to be a progressive process, in agreement with optical emission spectroscopy and deposit analysis, characterized by an increase of the energy flux that could be due to the oxidation of the growing metal film. On the contrary, oxide-metal transition is abrupt, and a high energy is released at the beginning that could not be attributed to a chemical reaction. The possible effect of O{sup −} ions at this step was discussed. - Highlights: • We use real-time energy flux measurements to study reactive magnetron sputtering. • At transitions rise of the energy flux transferred to the substrate is observed. • At the metal-oxide transition energy is released by oxidation of the Al growing film. • At the oxide-metal transition the energy transfer may be due to O{sup −} born at the target. • Energy flux study gives some insight into mechanisms involved in the film growth.

  2. Effect of Surface States on Joining Mechanisms and Mechanical Properties of Aluminum Alloy (A5052 and Polyethylene Terephthalate (PET by Dissimilar Friction Spot Welding

    Directory of Open Access Journals (Sweden)

    Farazila Yusof

    2016-04-01

    Full Text Available In this research, polyethylene terephthalate (PET, as a high-density thermoplastic sheet, and Aluminum A5052, as a metal with seven distinct surface roughnesses, were joined by friction spot welding (FSW. The effect of A5052’s various surface states on the welding joining mechanism and mechanical properties were investigated. Friction spot welding was successfully applied for the dissimilar joining of PET thermoplastics and aluminum alloy A5052. During FSW, the PET near the joining interface softened, partially melted and adhered to the A5052 joining surface. The melted PET evaporated to form bubbles near the joining interface and cooled, forming hollows. The bubbles have two opposite effects: its presence at the joining interface prevent PET from contacting with A5052, while bubbles or hollows are crack origins that induce crack paths which degrade the joining strength. On the other hand, the bubbles’ flow pushed the softened PET into irregularities on the roughened surface to form mechanical interlocking, which significantly improved the strength. The tensile-shear failure load for an as-received surface (0.31 μ m Ra specimen was about 0.4–0.8 kN while that for the treated surface (>0.31 μ m Ra specimen was about 4.8–5.2 kN.

  3. Structural and magnetic properties of yttrium iron garnet (YIG) and yttrium aluminum iron garnet (YAIG) nanoferrites prepared by microemulsion method

    Energy Technology Data Exchange (ETDEWEB)

    Akhtar, Majid Niaz, E-mail: majidniazakhtar@ciitlahore.edu.pk [Department of Physics, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Department of Mechanical and Materials Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Bakar Sulong, Abu [Department of Mechanical and Materials Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Khan, Muhammad Azhar [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Ahmad, Mukhtar [Department of Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan); Murtaza, Ghulam [Centre for Advanced Studies in Physics, G.C. University, Lahore, Pakistan" f Department of Mechanical Engineering, COMSATS Institute of Information Technology Sahiwal Pakistan (Pakistan); Raza, M.R. [Department of Mechanical and Materials Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Department of Mechanical Engineering, COMSATS Institute of Information Technology Sahiwal (Pakistan); Raza, R.; Saleem, M. [Department of Physics, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Kashif, M. [Department of Physics, Govt. College University Faisalabad (Pakistan)

    2016-03-01

    Yttrium iron garnet (YIG) and yttrium aluminum iron garnet (YAIG) nanoferrite samples were synthesized by microemulsion method. The effect of sintering was examined by heating the samples at 900, 1000, and 1100 °C. The YIG and YAIG samples were then characterized using X-ray diffraction and field-emission scanning electron microscopy. Static and dynamic magnetic properties were measured by evaluating initial permeability, Q factor, and vibrating sample magnetometry properties of YIG and YAIG samples. YIG samples sintered at 1100 °C showed higher initial permeability and Q factor compared with YAIG samples. However, hysteresis loops also showed variations in the saturation magnetization, remanence, and coercivity of YIG and YAIG samples sintered at 900, 1000, and 1100 °C. The observed magnetic parameter such as saturation magnetization, coercivity and initial permeability are strongly affected by increasing temperature. The saturation magnetization and coercivity of YIG and YAIG nanoferrites were found in the range 11.56–19.92 emu/g and 7.30–87.70 Oe respectively. Furthermore, the decreasing trends in the static and magnetic properties of YAIG samples may be due to the introduction of Al ions in the YIG crystal lattice. Thus, YIG and YAIG sintered at 1100 °C can be used for wide-ranging frequency applications. - Highlights: • Static and dynamic magnetic properties of YIG and YAIG nanoferrites were determined. • Saturation magnetization, Q and initial permeability increased in YIG nanoferites. • Possible use of these nanoferrites for sensing and switching applications.

  4. Invisible Display in Aluminum

    DEFF Research Database (Denmark)

    Prichystal, Jan Phuklin; Hansen, Hans Nørgaard; Bladt, Henrik Henriksen

    2005-01-01

    for an integrated display in a metal surface is often ruled by design and functionality of a product. The integration of displays in metal surfaces requires metal removal in order to clear the area of the display to some extent. The idea behind an invisible display in Aluminum concerns the processing of a metal...

  5. PREPARATION AND CHARACTERIZATION OF SUPERHYDROPHOBIC FEP-TEFLON SURFACES

    NARCIS (Netherlands)

    BUSSCHER, HJ; STOKROOS, [No Value; VANDERMEI, HC; ROUXHET, PG; SCHAKENRAAD, JM

    1992-01-01

    Superhydrophobic FEP-Teflon was prepared by argon ion etching followed by oxygen glow discharge treatment of commercially available FEP-Teflon sheet material. This combined treatment yielded an increase in water contact angle from 109-degrees to > 140-degrees. Ion etching alone caused a small increa

  6. PREPARATION AND CHARACTERIZATION OF SUPERHYDROPHOBIC FEP-TEFLON SURFACES

    NARCIS (Netherlands)

    BUSSCHER, HJ; STOKROOS, [No Value; VANDERMEI, HC; ROUXHET, PG; SCHAKENRAAD, JM

    1992-01-01

    Superhydrophobic FEP-Teflon was prepared by argon ion etching followed by oxygen glow discharge treatment of commercially available FEP-Teflon sheet material. This combined treatment yielded an increase in water contact angle from 109-degrees to > 140-degrees. Ion etching alone caused a small increa

  7. Hybrid Aluminum Composite Materials Based on Carbon Nanostructures

    Directory of Open Access Journals (Sweden)

    Tatiana S. Koltsova

    2015-09-01

    Full Text Available We investigated formation of carbon nanofibers grown by chemical deposition (CVD method using an acetylene-hydrogen mixture on the surface of micron-sized aluminum powder particles. To obtain uniform distribution of the carbon nanostructures on the particles we deposited nickel catalyst on the surface by spraying from the aqueous solution of nickel nitrate. It was found that increasing the time of the synthesis lowers the rate of growth of carbon nanostructures due to the deactivation of the catalyst. The Raman spectroscopy measurements confirm the presence of disordered carbon corresponding to CNFs in the specimen. X-ray photoelectron spectroscopy showed the presence of aluminum carbide in the hot pressed samples. An aluminum composite material prepared using 1 wt.% CNFs obtained by uniaxial cold pressing and sintering showed 30% increase in the hardness compared to pure aluminum, whereas the composites prepared by hot pressing showed 80% increase in the hardness. Composite materials have satisfactory ductility. Thus, the aluminum based material reinforced with carbon nanostructures should be appropriate for creating high-strength and light compacts for aerospace and automotive applications and power engineering.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7355

  8. Preparing bioactive surface of polystyrene with hydrophobin for trypsin immobilization

    Science.gov (United States)

    Niu, Baolong; Li, Bingzhang; Wang, Huifang; Guo, Ruijie; Liang, HaiXia; Qiao, Mingqiang; Li, Wenfeng

    2016-05-01

    A simple and reliable enzyme immobilization technique which can retain their catalytic activity for a long time is interest in many technologies. Here, the trypsin was immobilized by physisorption on polystyrene (PS) surface coated with a class I hydrophobin recombinant HGFI (rHGFI). X-ray photoelectron spectroscopy and water-contact-angle measurements demonstrated that the hydrophobicity of the PS could be well improved by rHGFI modification, and the self-assembled rHGFI showed an admirable stability on the hydrophobic PS surface against hot SDS rinsing. The enzyme activity assay illustrated that the capacity of rHGFI could enable it to well intermediate trypsin on PS surface and allow its immobilization lasting in an active form. The results obtained in this work show a way that surface modification with rHGFI should be an easy and feasible strategy for applications of enzyme-based catalytic surfaces in biosensing.

  9. Structure and strength of aluminum with sub-micrometer/micrometer grain size prepared by spark plasma sintering

    DEFF Research Database (Denmark)

    Le, G.M.; Godfrey, A.; Hansen, Niels

    2013-01-01

    A spark plasma sintering (SPS) technique has been applied to prepare fully dense Al samples from Al powder. By applying a sintering temperature of 600°C and a loading pressure of 50MPa, fully recrystallized samples of nearly 100% density with average grain sizes of 5.2μm, 1.3μm and 0.8μm have been...... the initial powder particle size. The SPS samples show higher strength than Al samples with an identical grain size prepared using thermo-mechanical processing, and a better strength-ductility combination, with the 1.3μm grain size sample showing a yield strength (σ0.2%) of 140MPa and a uniform elongation...

  10. Utilization of En Ac-42100 Cast Aluminum Alloy for Casting of Critical Components. I. Preparation and Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Vanko Branislav

    2014-12-01

    Full Text Available Requirement on the minimum value of elongation for critical components is about 15 %. The research deals with the possibility of replacing the dendritic morphology of primary solid solution and brittle eutectic silicon plates with finer particles with a more suitable morphology and size, and the possibility of increasing the mechanical properties. Introduced first part is focused on the process of preparation of experimental material and mechanical properties.

  11. What do we need for a superhydrophobic surface? A review on the recent progress in the preparation of superhydrophobic surfaces

    NARCIS (Netherlands)

    Li, X.; Reinhoudt, David; Crego Calama, Mercedes

    2007-01-01

    Superhydrophobic surfaces have drawn a lot of interest both in academia and in industry because of the self-cleaning properties. This critical review focuses on the recent progress (within the last three years) in the preparation, theoretical modeling, and applications of superhydrophobic surfaces.

  12. Effect of Surface Preparation on CLAM/CLAM Hot Isostatic Pressing diffusion bonding joints

    Science.gov (United States)

    Li, C.; Huang, Q.; Zhang, P.

    2009-04-01

    Surface preparation is essential for the Hot Isostatic Pressing (HIP) diffusion bonding of RAFM steels. Hot Isostatic Pressing (HIP) diffusion bonding experiments on China Low Activation Martensitic (CLAM) steel was performed to study the effect of surface preparation. A few approaches such as hand lapping, dry-milling and grinding etc., were used to prepare the faying surfaces of the HIP joints. Different sealing techniques were used as well. The HIP parameters were 150 MPa/3 h/1150 °C. After post HIP heat treatment (PHHT), the tensile and Charpy impact tests were carried out. The results showed that hand lapping was not suitable to prepare the faying surfaces of HIP diffusion bonding specimens although the surface roughness by hand lapping was very low.

  13. Preparation and controlled-release studies of a protocatechuic acid-magnesium/aluminum-layered double hydroxide nanocomposite

    Directory of Open Access Journals (Sweden)

    Barahuie F

    2013-05-01

    Full Text Available Farahnaz Barahuie,1 Mohd Zobir Hussein,1 Samer Hasan Hussein-Al-Ali,2 Palanisamy Arulselvan,3 Sharida Fakurazi,3,4 Zulkarnain Zainal11Materials Synthesis and Characterization Laboratory, Institute of Advanced Technology (ITMA, 2Laboratory of Molecular Biomedicine, Institute of Bioscience, 3Laboratory of Vaccines and Immunotherapeutics, Institute of Bioscience, 4Department of Human Anatomy, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, MalaysiaAbstract: In the study reported here, magnesium/aluminum (Mg/Al-layered double hydroxide (LDH was intercalated with an anticancer drug, protocatechuic acid, using ion-exchange and direct coprecipitation methods, with the resultant products labeled according to the method used to produce them: “PANE” (ie, protocatechuic acid-Mg/Al nanocomposite synthesized using the ion-exchange method and “PAND” (ie, protocatechuic acid-Mg/Al nanocomposite synthesized using the direct method, respectively. Powder X-ray diffraction and Fourier transform infrared spectroscopy confirmed the intercalation of protocatechuic acid into the inter-galleries of Mg/Al-LDH. The protocatechuic acid between the interlayers of PANE and PAND was found to be a monolayer, with an angle from the z-axis of 8° for PANE and 15° for PAND. Thermogravimetric and differential thermogravimetric analysis results revealed that the thermal stability of protocatechuic acid was markedly enhanced upon intercalation. The loading of protocatechuic acid in PANE and PAND was estimated to be about 24.5% and 27.5% (w/w, respectively. The in vitro release study of protocatechuic acid from PANE and PAND in phosphate-buffered saline at pH 7.4, 5.3, and 4.8 revealed that the nanocomposites had a sustained release property. After 72 hours incubation of PANE and PAND with MCF-7 human breast cancer and HeLa human cervical cancer cell lines, it was found that the nanocomposites had suppressed the growth of these cancer cells

  14. Preparation and biocompatibility of BSA monolayer on silicon surface.

    Science.gov (United States)

    Tao, Caihong; Zhang, Junyan; Yang, Shengrong

    2011-06-01

    This paper describes a general strategy for grafting protein molecules on silicon surface by using dopamine as adhesive layer. With this method, silicon surface had been successfully modified by BSA monolayer. Fourier transform infrared spectra, X-ray photoelectron spectroscopy, contact angle analysis and atomic force microscopy confirmed the sequential grafting of initiator and protein molecules. Cell adhesion experiments with PC-12 cells showed that the obtained monolayer exhibits good biocompatibility. The corrosion resistance behavior of the polydopamine and BSA modified silicon wafers was investigated by potentiodynamic test, which indicated that the modified surfaces exhibited a better anti-corrosion capability than silicon surface. All these results must be valuable for the application of protein monolayer in biological and biomedical technology.

  15. Comparing Laser Welding Technologies with Friction Stir Welding for Production of Aluminum Tailor-Welded Blanks

    Energy Technology Data Exchange (ETDEWEB)

    Hovanski, Yuri; Carsley, John; Carlson, Blair; Hartfield-Wunsch, Susan; Pilli, Siva Prasad

    2014-01-15

    A comparison of welding techniques was performed to determine the most effective method for producing aluminum tailor-welded blanks for high volume automotive applications. Aluminum sheet was joined with an emphasis on post weld formability, surface quality and weld speed. Comparative results from several laser based welding techniques along with friction stir welding are presented. The results of this study demonstrate a quantitative comparison of weld methodologies in preparing tailor-welded aluminum stampings for high volume production in the automotive industry. Evaluation of nearly a dozen welding variations ultimately led to down selecting a single process based on post-weld quality and performance.

  16. Aluminum microstructures on anodic alumina for aluminum wiring boards.

    Science.gov (United States)

    Jha, Himendra; Kikuchi, Tatsuya; Sakairi, Masatoshi; Takahashi, Hideaki

    2010-03-01

    The paper demonstrates simple methods for the fabrication of aluminum microstructures on the anodic oxide film of aluminum. The aluminum sheets were first engraved (patterned) either by laser beam or by embossing to form deep grooves on the surface. One side of the sheet was then anodized, blocking the other side by using polymer mask to form the anodic alumina. Because of the lower thickness at the bottom part of the grooves, the part was completely anodized before the complete oxidation of the other parts. Such selectively complete anodizing resulted in the patterns of metallic aluminum on anodic alumina. Using the technique, we fabricated microstructures such as line patterns and a simple wiring circuit-board-like structure on the anodic alumina. The aluminum microstructures fabricated by the techniques were embedded in anodic alumina/aluminum sheet, and this technique is promising for applications in electronic packaging and devices.

  17. Preparation Of Control Space For Remeshing Of Polygonal Surfaces

    Directory of Open Access Journals (Sweden)

    Tomasz Jurczyk

    2013-01-01

    Full Text Available The subject of the article concerns the issues of remeshing, transforming a polygonal mesh into a triangular mesh adapted to surface. From the initial polygonal mesh the curvature of surface and boundary is retrieved and used to calculate a metric tensor varying in three-dimensional space. In the proposed approach the curvature is computed using local approximation of surfaces and curves on the basis of vertices of the polygonal mesh. An essential part of the presented remeshing procedure is creation of a control space structure based on the retrieved discrete data. The subsequent process of remeshing is then supervised by the contents of this auxiliary structure. The article presents various aspects related to the procedure of initialization, creation and adjusting the control space structure.

  18. Supersonic Retropulsion Surface Preparation of Carbon Fiber Reinforced Epoxy Composites for Adhesive Bonding

    Science.gov (United States)

    Palmieri, Frank L.; Belcher, Marcus A.; Wohl, Christopher J.; Blohowiak, Kay Y.; Connell, John W.

    2013-01-01

    Surface preparation is widely recognized as a key step to producing robust and predictable bonds in a precise and reproducible manner. Standard surface preparation techniques, including grit blasting, manual abrasion, and peel ply, can lack precision and reproducibility, which can lead to variation in surface properties and subsequent bonding performance. The use of a laser to ablate composite surface resin can provide an efficient, precise, and reproducible means of preparing composite surfaces for adhesive bonding. Advantages include elimination of physical waste (i.e., grit media and sacrificial peel ply layers that ultimately require disposal), reduction in process variability due to increased precision (e.g. increased reproducibility), and automation of surface preparation, all of which improve reliability and process control. This paper describes a Nd:YAG laser surface preparation technique for composite substrates and the mechanical performance and failure modes of bonded laminates thus prepared. Additionally, bonded specimens were aged in a hot, wet environment for approximately one year and subsequently mechanically tested. The results of a one year hygrothermal aging study will be presented.

  19. Laser Surface Preparation for Adhesive Bonding of Ti-6Al-4V

    Science.gov (United States)

    Belcher, Marcus A.; List, Martina S.; Wohl, Christopher J.; Ghose, Sayata; Watson, Kent A.; Hopkins, John W.; Connell, John W.

    2010-01-01

    Adhesively bonded structures are potentially lighter in weight than mechanically fastened ones, but existing surface treatments are often considered unreliable. Two main problems in achieving reproducible and durable adhesive bonds are surface contamination and variability in standard surface preparation techniques. In this work three surface pretreatments were compared: laser etching with and without grit blasting and conventional Pasa-Jell treatment. Ti-6Al-4V surfaces were characterized by contact angle goniometry, optical microscopy, and X-ray photoelectron spectroscopy (XPS). Laser -etching was found to produce clean surfaces with precisely controlled surface topographies and PETI-5 lap shear strengths and durabilities were equivalent to those produced with Pasa-Jell.

  20. Preparation of well-aligned carbon nanotubes/silicon nanowires core-sheath composite structure arrays in porous anodic aluminum oxide templates

    Institute of Scientific and Technical Information of China (English)

    李梦轲; 力虎林; 陆梅; 王成伟

    2002-01-01

    The well-aligned carbon nanotubes (CNTs) arrays with opened ends were prepared in ordered pores of anodic aluminum oxide (AAO) template by the chemical vapor deposition (CVD) method. After then, silicon nanowires (SiNWs) were deposited in the hollow cavities of CNTs. By using this method, CNTs/SiNWs core-sheath composite structure arrays were synthesized successfully. Growing structures and physical properties of the CNTs/SiNWs composite structure arrays were analyzed and researched by the scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction spectrum (XRD), respectively. The field emission (FE) behavior of the CNTs/SiNWs composite structure arrays was studied based on Fowler-Nordheim tunneling mechanism and current-voltage (/-V) curve. And the photoluminescence (PL) was also characterized. Significantly, the CNTs/SiNWs core-sheath composite structure nanowire fabricated by AAO template method is characteristic of a metal/semiconductor (M/S) behavior and can be

  1. Hot-wire chemical vapor deposition prepared aluminum doped p-type microcrystalline silicon carbide window layers for thin film silicon solar cells

    Science.gov (United States)

    Chen, Tao; Köhler, Florian; Heidt, Anna; Carius, Reinhard; Finger, Friedhelm

    2014-01-01

    Al-doped p-type microcrystalline silicon carbide (µc-SiC:H) thin films were deposited by hot-wire chemical vapor deposition at substrate temperatures below 400 °C. Monomethylsilane (MMS) highly diluted in hydrogen was used as the SiC source in favor of SiC deposition in a stoichiometric form. Aluminum (Al) introduced from trimethylaluminum (TMAl) was used as the p-type dopant. The material property of Al-doped p-type µc-SiC:H thin films deposited with different deposition pressure and filament temperature was investigated in this work. Such µc-SiC:H material is of mainly cubic (3C) SiC polytype. For certain conditions, like high deposition pressure and high filament temperature, additional hexagonal phase and/or stacking faults can be observed. P-type µc-SiC:H thin films with optical band gap E04 ranging from 2.0 to 2.8 eV and dark conductivity ranging from 10-5 to 0.1 S/cm can be prepared. Such transparent and conductive p-type µc-SiC:H thin films were applied in thin film silicon solar cells as the window layer, resulting in an improved quantum efficiency at wavelengths below 480 nm.

  2. Corrosion Behavior of Top and Bottom Surfaces for Single-Side and Double-Side Friction Stir Welded 7085-T7651 Aluminum Alloy Thick Plate Joints

    Science.gov (United States)

    Xu, Weifeng; Zhang, Wei; Wu, Xiaoli

    2017-03-01

    Thick plate joints of 7085-T7451 aluminum alloy were obtained through both single-side and double-side friction stir welding (SS or DS-FSW). The chloride ions effects on the corrosion behavior of the top and bottom surfaces of the joints were examined by cyclic potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). Results show that the corrosion susceptibility was suppressed significantly in the weld nugget zone, while the base material and heat-affected zone were prone to be corrosion attacked. For the SS-FSWed joint, the top surface showed a higher corrosion resistance than that of the bottom surface, but the larger corrosive heterogeneity was observed between the top and bottom surfaces compared with the two welds of DS-FSWed joint, which was confirmed by the morphology of corrosion attack. A deep insight on the microstructure of the joints indicates that the intermetallic particles played a key role in the corrosion behavior of the FSWed AA7085 aluminum alloy joints in chloride solution.

  3. Corrosion Behavior of Top and Bottom Surfaces for Single-Side and Double-Side Friction Stir Welded 7085-T7651 Aluminum Alloy Thick Plate Joints

    Science.gov (United States)

    Xu, Weifeng; Zhang, Wei; Wu, Xiaoli

    2017-01-01

    Thick plate joints of 7085-T7451 aluminum alloy were obtained through both single-side and double-side friction stir welding (SS or DS-FSW). The chloride ions effects on the corrosion behavior of the top and bottom surfaces of the joints were examined by cyclic potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). Results show that the corrosion susceptibility was suppressed significantly in the weld nugget zone, while the base material and heat-affected zone were prone to be corrosion attacked. For the SS-FSWed joint, the top surface showed a higher corrosion resistance than that of the bottom surface, but the larger corrosive heterogeneity was observed between the top and bottom surfaces compared with the two welds of DS-FSWed joint, which was confirmed by the morphology of corrosion attack. A deep insight on the microstructure of the joints indicates that the intermetallic particles played a key role in the corrosion behavior of the FSWed AA7085 aluminum alloy joints in chloride solution.

  4. Influence of surface preparation on fusion bonding of thermoplastic composites

    NARCIS (Netherlands)

    Sacchetti, F.; Grouve, W.J.B.; Warnet, L.L.; Fernandez Villegas, I.

    2015-01-01

    Carbon fibre-reinforced thermoplastic composites laminates (CFRP) meant for fusion bonding have been moulded using different release media. The potential contamination of the laminate surface by the release media and its effect on the mechanical performance of fusion bonded joints was studied. The p

  5. Simple method for preparation of nanostructure on microchannel surface and its usage for enzyme-immobilization.

    Science.gov (United States)

    Miyazaki, Masaya; Kaneno, Jun; Uehara, Masato; Fujii, Masayuki; Shimizu, Hazime; Maeda, Hideaki

    2003-03-07

    We developed a novel preparation method of nanostructure on the microchannel surface formed by sol-gel like simple treatment with 3-aminopropyltriethoxysilane, which is suitable for a highly efficient enzyme-immobilized microchannel reactor.

  6. Gas evolution behavior of aluminum in mortar

    Energy Technology Data Exchange (ETDEWEB)

    Hashizume, Shuji; Matsumoto, Junko; Banba, Tsunetaka [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-10-01

    As a part of study of leaching behavior for solidified dry low level radioactive waste, gas evolution behavior of aluminum in mortar was investigated, and a plan of our research was proposed. The effect of pH on corrosion rate of aluminum, corrosion product, time dependency of corrosion rate of aluminum in mortar, change of corrosion mechanism, the effects of Na, Ca and Cl ions on corrosion rate of aluminum in mortar and corrosion behavior of aluminum when aluminum was used as sacrificed anode in reinforced concrete were previously clarified. Study of the effects of environmental factors such as pH, kind of ions and temperature on gas evolution behavior of aluminum and the effect of aluminum/carbon steel surface ratio no gas evolution behavior of aluminum were planed. (author). 75 refs.

  7. Cerium oxide as conversion coating for the corrosion protection of aluminum

    Directory of Open Access Journals (Sweden)

    JELENA GULICOVSKI

    2013-11-01

    Full Text Available CeO2 coatings were formed on the aluminum after Al surface preparation, by dripping the ceria sol, previously prepared by forced hydrolysis of Ce(NO34. The anticorrosive properties of ceria coatings were investigated by the electrochemical impedance spectroscopy (EIS during the exposure to 0.03 % NaCl. The morphology of the coatings was examined by the scanning electron microscopy (SEM. EIS data indicated considerably larger corrosion resistance of CeO2-coated aluminum than for bare Al. The corrosion processes on Al below CeO2 coating are subjected to more pronounced diffusion limitations in comparison to the processes below passive aluminum oxide film, as the consequence of the formation of highly compact protective coating. The results show that the deposition of ceria coatings is an effective way to improve corrosion resistance for aluminum.

  8. Elements inter-diffusion in the turning of wear-resistance aluminum bronze

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Inter-diffusion of elements between the tool and the workpiece during the turning of aluminum bronze using high-speed steel and cemented carbide tools have been studied. The tool wear samples were prepared by using M2 high-speed steel and YW1 cemented carbide tools to turn a novel high strength, wear-resistance aluminum bronze without coolant and lubricant. Adhesion of workpiece materials was found on all tools' surface. The diffusion couples made of tool materials and aluminum bronze were prepared to simulate the inter-diffusion during the machining. The results obtained from tool wear samples were compared with those obtained from diffusion couples. Strong inter-diffusion between the tool materials and the aluminum bronze was observed in all samples. It is concluded that diffusion plays a significant role in the tool wear mechanism.

  9. Protein adsorption on gradient surfaces on polyethylene prepared in a shielded gas plasma

    NARCIS (Netherlands)

    Spijker, Hendrikje; Bos, Roelof; van Oeveren, Willem; de Vries, Jacob; Busscher, Hendrik

    1999-01-01

    In this study, a new and simple method is described to prepare wettability gradients on polymers by means of glow discharge in a partly shielded argon plasma. The surface characteristics of thus prepared gradients on low density polyethylene were determined by contact angle measurements and electron

  10. Structural and magnetic properties of zinc- and aluminum-substituted cobalt ferrite prepared by co-precipitation method

    Indian Academy of Sciences (India)

    S T Alone; K M Jadhav

    2008-01-01

    Spinal ferrites having the general formula Co1-ZnFe2-AlO4 ( = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6) were prepared using the wet chemical co-operation technique. The samples were annealed at 800°C for 12 h and were studied by means of X-ray diffraction, magnetization and low field AC susceptibility measurements. The X-ray analysis showed that all the samples had single-phase cubic spinel structure. The variation of lattice constant with Zn and Al concentration deviates from Vegard's law. The saturation magnetization and magneton number B measured at 300 K using high field hysteresis loop technique decreases with increasing , suggesting decrease in ferrimagnetic behaviour. Curie temperature C deduced from AC susceptibility data decreases with , suggesting a decrease in ferrimagnetic behaviour.

  11. Micro- and nano-porous surface patterns prepared by surface-confined directional melt crystallization of solvent

    Science.gov (United States)

    Kim, Byoung Soo; Kim, Hyun Jin; An, Suyeong; Chi, Sangwon; Kim, Junseok; Lee, Jonghwi

    2017-07-01

    Recently, numerous attempts have been made to engineer micro- and nano-porous surface patterns or to develop convenient preparation methods for the practical applications of self-cleaning surfaces, water-repellent surfaces, novel textures, etc. Herein, we introduce a simple, cheap, and repeatable crystallization-based method to produce porous surface structures, on any surface of already fabricated polymeric materials. Contact of the solvent phase with cooled polymer surfaces enabled the limited dissolution of the surfaces and the subsequent extremely fast melt crystallization of the solvent. After removing the crystals, various micro- and nano-porous patterns were obtained, whose pore sizes ranged over three orders of magnitude. Pore depth was linearly dependent on the dissolution time. Crystal growth was mainly directed normal to the surfaces, but it was also controlled in-plane, resulting in cylindrical or lamellar structures. Superhydrophobic surfaces were successfully prepared on both polystyrene and polycarbonate. This process offers a novel surface engineering tool for a variety of polymer surfaces, whose topology can be conveniently controlled over a wide range by crystal engineering.

  12. 热型连铸铝线的制备及其显微组织和性能%Preparation of aluminum wire by Ohno continuous casting and its microstructure and properties

    Institute of Scientific and Technical Information of China (English)

    胡炜; 王彦红; 赵小军; 肖来荣; 饶博; 章玮

    2015-01-01

    采用自制的热型连铸设备制备铝线材料,研究铸型温度和拉铸速度等工艺参数对材料表面质量、显微组织及力学性能的影响,通过对最佳工艺条件下制备的铸锭断口形貌进行观察和分析,探讨其相关机理。结果表明:当铸型温度为675~685℃、拉铸速度为90~120 mm/min时,可以制备出表面质量较佳的铸锭;同时,工艺参数会对晶体的择优取向产生一定影响,当铸型温度和拉铸速度分别为680℃和90 mm/min时,晶体的取向更倾向于沿〈100〉方向生长,铸型温度越高,铸锭力学性能越优异。当拉铸速度为90 mm/min时,制备的热型连铸铝线具有最佳的塑性加工能力。相比于普通多晶铝线,热型连铸铝线具有更好的塑性。%Aluminum wires were prepared using the self-made Ohno continuous casting equipment. The effects of process parameters, such as the mold temperature and casting rate, on the surface quality, microstructure and mechanical properties of aluminum wires were investigated. Besides, the microstructures of fracture surfaces of Al wires prepared under optimal process parameters were evaluated, and the relevant mechanisms were identified. The results show that the Al ingots with good surface quality can be successfully fabricated at the mold temperature of 675−685℃ and the casting speed of 90−120 mm/min. Meanwhile, the process parameters have a great effect on the preferred orientation of crystals. When the mold temperature is 680℃ and the casting speed is 90 mm/min, the crystal orientation of grain tends to grow along the direction of〈100〉. Moreover, when the casting speed is constant, the mechanical properties of ingots are improved with the increasing mold temperature. Furthermore, when the casting speed is 90 mm/min, the plastic processing capacity is the best. In comparison to polycrystalline Al wires, the Al wires prepared by Ohno continuous casting have better integrated

  13. Preparation and Properties of Zirconium Hydride on the Surface of MCM-41 Mesoporous Molecular Sieves

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Zirconium monohydride bonded to the framework oxygen of MCM-41 surface was prepared by the reaction of tetraneopentyl zirconium with MCM-41 surface hydroxyl groups, followed by the hydrogenolysis of the resulted product. The surface hydride was characterized by using infrared spectroscopy, solid-state NMR, elemental analysis, gas-phase chromatography and chemical probing reaction. It was shown that this surface species is stable below 150 ℃ and can catalytically crack alkanes into methane and ethane at 100 ℃.

  14. Facile method for preparing superoleophobic surfaces with hierarchical microcubic/nanowire structures

    Science.gov (United States)

    Kwak, Wonshik; Hwang, Woonbong

    2016-02-01

    To facilitate the fabrication of superoleophobic surfaces having hierarchical microcubic/nanowire structures (HMNS), even for low surface tension liquids including octane (surface tension = 21.1 mN m-1), and to understand the influences of surface structures on the oleophobicity, we developed a convenient method to achieve superoleophobic surfaces on aluminum substrates using chemical acid etching, anodization and fluorination treatment. The liquid repellency of the structured surface was validated through observable experimental results the contact and sliding angle measurements. The etching condition required to ensure high surface roughness was established, and an optimal anodizing condition was determined, as a critical parameter in building the superoleophobicity. The microcubic structures formed by acid etching are essential for achieving the formation of the hierarchical structure, and therefore, the nanowire structures formed by anodization lead to an enhancement of the superoleophobicity for low surface tension liquids. Under optimized morphology by microcubic/nanowire structures with fluorination treatment, the contact angle over 150° and the sliding angle less than 10° are achieved even for octane.

  15. Clean and cost-effective dry boundary lubricants for aluminum forming.

    Energy Technology Data Exchange (ETDEWEB)

    Erdemir, A.; Fenske, G. R.

    1997-12-05

    Preliminary research in our laboratory has demonstrated that boric acid is an effective lubricant with an unusual capacity to reduce sliding fiction (providing friction coefficients as low as 0.02) and wear of metallic and ceramic materials. More recent studies have revealed that water or methanol solutions of boric acid can be used to prepare strongly bonded layers of boric acid on aluminum surfaces. It appears that boric acid molecules have a strong tendency to bond chemically to the naturally oxidized surfaces of aluminum and its alloys and to make these surfaces very slippery. Recent metal formability tests indicated that the boric acid films formed on aluminum surfaces by spraying or dipping worked quite well; improving draw scale performance by 58 to 75%. These findings have increased the prospect that boric acid can be formulated and optimized as an effective boundary lubricant and used to solve the friction, galling, and severe wear problems currently encountered in cold-forming of aluminum products. Accordingly, the major goal of this paper is to demonstrate the usefulness and lubrication capacity of thin boric acid films formed on aluminum surfaces by simple dipping or spraying processes and to describe the lubrication mechanisms under typical metal forming conditions. We will also examine the nature of chemical bonding between boric acid and aluminum surfaces and develop new ways to optimize its performance as an effective boundary lubricant.

  16. Investigation of Surface Preparations to Enhance Photon Doppler Velocimetry Measurements

    Science.gov (United States)

    2015-08-01

    Illustration depicting differences between a specular reflector (left) and a diffuse reflector (right). Solid blue arrows portray incident light rays and...explain the results obtained. When a surface is finished with a smooth, flat finish the reflection pattern tends toward that of a specular reflector...between a specular reflector (left) and a diffuse reflector (right). Solid blue arrows portray incident light rays and dashed red arrows portray

  17. Preparation of Chemical Samples On Relevant Surfaces Using Inkjet Technology

    Science.gov (United States)

    2013-04-01

    moisture is absorbed by the chemical from the air. The weight eventually stabilizes as the chemical moisture content approaches that of the air. This...when similar chemical solutions are paint -sprayed onto a hot (70 °C) substrate, the crystals are smaller, more numerous, and more closely spaced. To...gravity, surface tension, particle size, and chemical composition. Substrate material may be wood, metal, glass, plastic, concrete, road blacktop, dirt

  18. Preparation of Zirconia-Ceria Powders with High Specific Surface Area

    Institute of Scientific and Technical Information of China (English)

    Wang Enguo; Mei Fang

    2004-01-01

    Zirconia-ceria mixed oxide powders were prepared by high temperature aging method.The effects of the temperature and the time of aging, cerium content and calcination on powder performance were studied.The result shows that high temperature aging is an efficient way of preparation of ZrO2-CeO2 mixed oxide powders with high specific surface area and good thermal stability, and that addition of a small amount of cerium to hydrous zirconia can promote the preparation of high specific surface area powders.

  19. Effect of Pore Size and Film Thickness on Gold-Coated Nanoporous Anodic Aluminum Oxide Substrates for Surface-Enhanced Raman Scattering Sensor.

    Science.gov (United States)

    Kassu, Aschalew; Farley, Carlton; Sharma, Anup; Kim, Wonkyu; Guo, Junpeng

    2015-11-30

    A sensitive surface enhanced Raman scattering chemical sensor is demonstrated by using inexpensive gold-coated nanoporous anodic aluminum oxide substrates. To optimize the performance of the substrates for sensing by the Surface-enhanced Raman scattering (SERS) technique, the size of the nanopores is varied from 18 nm to 150 nm and the gold film thickness is varied from 30 nm to 120 nm. The sensitivity of gold-coated nanoporous surface enhanced Raman scattering sensor is characterized by detecting low concentrations of Rhodamine 6G laser dye molecules. The morphology of the SERS substrates is characterized by atomic force microscopy. Optical properties of the nanoporous SERS substrates including transmittance, reflectance, and absorbance are also investigated. Relative signal enhancement is plotted for a range of substrate parameters and a detection limit of 10(-6) M is established.

  20. Shear-bond-strength of orthodontic brackets to aged nano-hybrid composite-resin surfaces using different surface preparation.

    Science.gov (United States)

    Demirtas, Hatice Kubra; Akin, Mehmet; Ileri, Zehra; Basciftci, Faruk Ayhan

    2015-01-01

    The aim of this study was to evaluate the effects of different surface preparation methods on the shear bond strength (SBS) of orthodontic metal brackets to aged nano-hybrid resin composite surfaces in vitro. A total of 100 restorative composite resin discs, 6 mm in diameter and 3 mm thick, were obtained and treated with an ageing procedure. After ageing, the samples were randomly divided as follows according to surface preparation methods: (1)Control, (2)37% phosphoric acid gel, (3)Sandblasting, (4)Diamond bur, (5)Air-flow and 20 central incisor teeth were used for the control etched group. SBS test were applied on bonded metal brackets to all samples. SBS values and residual adhesives were evaluated. Analysis of variance showed a significant difference (phybrid composite resin surfaces.

  1. Structure of a passivated Ge surface prepared from aqueous solution.

    Energy Technology Data Exchange (ETDEWEB)

    Lyman, P. F.; Sakata, O.; Marasco, D, L.; Lee, T.-L.; Breneman, K. D.; Keane, D. T.; Bedzyk, M. J.; Materials Science Division; Northwestern Univ.; Univ. of Wisconsin at Milwaukee

    2000-08-10

    The structure of a passivating sulfide layer on Ge(001) was studied using X-ray standing waves and X-ray fluorescence. The sulfide layer was formed by reacting clean Ge substrates in (NH{sub 4}){sub 2}S solutions of various concentrations at 80{sup o}C. For each treatment, a sulfide layer containing approximately two to three monolayers (ML) of S was formed on the surface, and an ordered structure was found at the interface that contained approximately 0.4 ML of S. Our results suggest the rapid formation of a glassy GeS{sub x} layer containing 1.5-2.5 ML S residing atop a partially ordered interfacial layer of bridge-bonded S. The passivating reaction appears to be self-limited to 2-3 ML at this reaction temperature.

  2. Laser Surface Preparation of Epoxy Composites for Secondary Bonding: Optimization of Ablation Depth

    Science.gov (United States)

    Palmieri, Frank L.; Hopkins, John; Wohl, Christopher J.; Lin, Yi; Connell, John W.; Belcher, Marcus A.; Blohowiak, Kay Y.

    2015-01-01

    Surface preparation has been identified as one of the most critical aspects of attaining predictable and reliable adhesive bonds. Energetic processes such as laser ablation or plasma treatment are amenable to automation and are easily monitored and adjusted for controlled surface preparation. A laser ablation process was developed to accurately remove a targeted depth of resin, approximately 0.1 to 20 micrometers, from a carbon fiber reinforced epoxy composite surface while simultaneously changing surface chemistry and creating micro-roughness. This work demonstrates the application of this process to prepare composite surfaces for bonding without exposing or damaging fibers on the surface. Composite panels were prepared in an autoclave and had a resin layer approximately 10 micrometers thick above the fiber reinforcement. These composite panels were laser surface treated using several conditions, fabricated into bonded panels and hygrothermally aged. Bond performance of aged, experimental specimens was compared with grit blast surface treated specimens using a modified double cantilever beam test that enabled accelerated saturation of the specimen with water. Comparison of bonded specimens will be used to determine how ablation depth may affect average fracture energies and failure modes.

  3. Preparation of lanthanum fluoride nanolayers by depositing ionic layers on silicon surface

    Energy Technology Data Exchange (ETDEWEB)

    Zhuchkov, B.S.; Tolstoi, V.P.; Murin, I.V.; Kirillov, S.N. [St. Petersburg State Univ. (Russian Federation)

    1995-11-10

    The kinetics of growth of LaF{sub 3} nanolayers on silicon surface was studied. Influences due to preparation conditions (the concentration and the pH values of the solution, the time of surface treatment, the number of cycles of ionic layer deposition) were evaluated.

  4. Aluminum for Plasmonics

    Science.gov (United States)

    2014-01-01

    in plasmon-enhanced light harvesting,14 photocatalysis ,511 surface- enhanced spectroscopies,1216 optics-based sensing,1722 nonlinear optics,2326...optical response of Al nanoparticles has appeared inconsistent relative to calculated spectra, even forwell-characterized geometries. Some studies have...model- ing their optical response. These results pro- vide a method for estimating the metallic purity of aluminum nanoparticles directly from their

  5. Optimization of process parameters of aluminum alloy AA 2014-T6 friction stir welds by response surface methodology

    OpenAIRE

    Ramanjaneyulu Kadaganchi; Madhusudhan Reddy Gankidi; Hina Gokhale

    2015-01-01

    The heat treatable aluminum–copper alloy AA2014 finds wide application in the aerospace and defence industry due to its high strength-to-weight ratio and good ductility. Friction stir welding (FSW) process, an emerging solid state joining process, is suitable for joining this alloy compared to fusion welding processes. This work presents the formulation of a mathematical model with process parameters and tool geometry to predict the responses of friction stir welds of AA 2014-T6 aluminum allo...

  6. Contribution of Iron and Aluminum Oxides to Electrokinetic Characteristics of Variable Charge Soils in Relation to Surface Charge

    Institute of Scientific and Technical Information of China (English)

    ZHANGHONG; ZHANGXIAO-NIAN

    1992-01-01

    The contribution of iron and aluminum oxides to electrokinetic characteristics of variable charge soils was studied through determination of electrophoretic mobilities of the red soils treated with either removal of iron oxides or coating of aluminum oxides,and of those deferrated under natural conditions.After removal of the iron oxides,zeta potentials of the latosol and the red earth decreased obviously with a shift of IEP to a lower pH,from 6.4 to 5.3 and 4.1 to 2.4 for the former and the latter,respectively,and the electrokinetic change for the latosol was greater than for the red earth.Zeta potentials of the kaolinite sample increased markedly after coated with iron oxides.The striking effect of iron oxides on electrokinetix properties of the soils was also demonstrated by the electrokinetic differences between the samples from the red and white zones of a plinthitic horizon formed naturally,and between the samples from the gley and bottom horizons of a paddy soil derived from a red earth.The coatings of aluminum oxides on the latosol and the yellow earth made their zeta potentials rise pronouncedly and their IEFs move toward higher pHs,from 6.2 to 6.8 and 4.3 to 5.3 for the former and the latter,respectively.The samples with different particle sizes also exhibited some electrokinetic variation.The experiment showed that the effects of iron and aluminum oxides were closely related to the pH and type of the soils.

  7. Influence of Oxygen Gas Ratio on the Properties of Aluminum-Doped Zinc Oxide Films Prepared by Radio Frequency Magnetron Sputtering.

    Science.gov (United States)

    Kim, Minha; Jang, Yong-Jun; Jung, Ho-Sung; Song, Woochang; Kang, Hyunil; Kim, Eung Kwon; Kim, Donguk; Yi, Junsin; Lee, Jaehyeong

    2016-05-01

    Aluminum-doped zinc oxide (AZO) thin films were deposited on glass and polyimide substrates using radio frequency magnetron sputtering. We investigated the effects of the oxygen gas ratio on the properties of the AZO films for Cu(In,Ga)Se2 thin-film solar cell applications. The structural and optical properties of the AZO thin films were measured using X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), and UV-Visible-NIR spectrophotometry. The oxygen gas ratio played a crucial role in controlling the optical as well as electrical properties of the films. When oxygen gas was added into the film, the surface AZO thin films became smoother and the grains were enlarged while the preferred orientation changed from (0 0 2) to (1 0 0) plane direction of the hexagonal phase. An improvement in the transmittance of the AZO thin films was achieved with the addition of 2.5-% oxygen gas. The electrical resistivity was highly increased even for a small amount of the oxygen gas addition.

  8. Partial oxidation of dimethyl ether using the structured catalyst Rh/Al2O3/Al prepared through the anodic oxidation of aluminum.

    Science.gov (United States)

    Yu, B Y; Lee, K H; Kim, K; Byun, D J; Ha, H P; Byun, J Y

    2011-07-01

    The partial oxidation of dimethyl ether (DME) was investigated using the structured catalyst Rh/Al2O3/Al. The porous Al2O3 layer was synthesized on the aluminum plate through anodic oxidation in an oxalic-acid solution. It was observed that about 20 nm nanopores were well developed in the Al2O3 layer. The thickness of Al2O3 layer can be adjusted by controlling the anodizing time and current density. After pore-widening and hot-water treatment, the Al2O3/Al plate was calcined at 500 degrees C for 3 h. The obtained delta-Al2O3 had a specific surface area of 160 m2/g, making it fit to be used as a catalyst support. A microchannel reactor was designed and fabricated to evaluate the catalytic activity of Rh/Al2O3/Al in the partial oxidation of DME. The structured catalyst showed an 86% maximum hydrogen yield at 450 degrees C. On the other hand, the maximum syngas yield by a pack-bed-type catalyst could be attained by using a more than fivefold Rh amount compared to that used in the structured Rh/Al2O3/Al catalyst.

  9. Preparation, anti-biofouling and drag-reduction properties of a biomimetic shark skin surface

    Directory of Open Access Journals (Sweden)

    Xia Pu

    2016-04-01

    Full Text Available Shark skin surfaces show non-smoothness characteristics due to the presence of a riblet structure. In this study, biomimetic shark skin was prepared by using the polydimethylsiloxane (PDMS-embedded elastomeric stamping (PEES method. Scanning electron microscopy (SEM was used to examine the surface microstructure and fine structure of shark skin and biomimetic shark skin. To analyse the hydrophobic mechanism of the shark skin surface microstructure, the effect of biomimetic shark skin surface microstructure on surface wettability was evaluated by recording water contact angle. Additionally, protein adhesion experiments and anti-algae adhesion performance testing experiments were used to investigate and evaluate the anti-biofouling properties of the surface microstructure of biomimetic shark skin. The recorded values of the water contact angle of differently microstructured surfaces revealed that specific microstructures have certain effects on surface wettability. The anti-biofouling properties of the biomimetic shark skin surface with microstructures were superior to a smooth surface using the same polymers as substrates. Moreover, the air layer fixed on the surface of the biomimetic shark skin was found to play a key role in their antibiont adhesion property. An experiment into drag reduction was also conducted. Based on the experimental results, the microstructured surface of the prepared biomimetic shark skin played a significant role in reducing drag. The maximum of drag reduction rate is 12.5%, which is higher than the corresponding maximum drag reduction rate of membrane material with a smooth surface.

  10. Preparation of Ce Film on Aluminum Alloy by Brush Plating and Its Corrosion Resistance%铝合金表面电刷镀制备稀土铈转化膜及其耐蚀性

    Institute of Scientific and Technical Information of China (English)

    付大海; 韩忠智; 唐鋆磊; 唐聿明; 左禹

    2011-01-01

    A rare earth Ce film was prepared on LY12 aluminum alloy by brush plating. The obtained Ce film showed layered structure, adhered well on the substrate and showed obviously increased corrosion resistance in NaCl solution. The influences of plating voltage and Ce concentration on the film properties were studied and the best corrosion resistance was obtained under the condition of 7 V and 20 g/L Ce salt concentration. After 480 h of salt fog testing, corrosion resistance of the brush plated surface was estimated to be above 8 grade. The corrosion current density decreased by one order of magnitude and the impedance at low frequency increased by about 30 times in contrast to the original LY12 alloy. Particularly, the strong oxidants are not included in the plating bath, hence the bath is more stable and may be easily recycled. The method may be used to increase corrosion resistance for aluminum alloy equipments with large areas at industrial cases.%利用电刷镀技术在铝合金表面制备了稀土铈转化膜,得到的稀土膜层厚度均匀,呈层状结构,与基体结合良好,在NaCl溶液中具有良好的耐蚀性.研究了刷镀电压和铈盐浓度对膜层耐蚀性的影响,得到在7 V电压和20 g/L铈盐浓度下制备的膜层具有良好耐蚀性能,经过480 h盐雾试验后,其表面耐蚀性评价达到8级以上,镀膜试样与原始LY12铝合金试样相比,腐蚀电流密度降低一个数量级,低频阻抗值则增大约30倍.该铝合金表面稀土转化膜电刷沉积溶液中不合强氧化剂,因此溶液长时间稳定且便于循环利用,可以对铝合金表面进行现场大面积常温刷镀,提高耐蚀性.

  11. Facile preparation of superhydrophobic surface with high adhesive forces based carbon/silica composite films

    Indian Academy of Sciences (India)

    Ruanbing Hu; Guohua Jiang; Xiaohong Wang; Xiaoguang Xi; Rijing Wang

    2013-11-01

    Glass substrates modified by carbon/silica composites are fabricated through a two-step process for the preparation of a superhydrophobic surface (water contact angle ≥ 150°). Carbon nanoparticles were first prepared through a deposition process on glass using a hydrothermal synthesis route, then the glass was modified by SiO2 using the hydrolysis reaction of tetraethylorthosilicate at room temperature. It is not only a facile method to create a superhydrophobic surface, but also helps to form a multi-functional surface with high adhesive forces.

  12. Preparation of Material Surface Structure Similar to Hydrophobic Structure of Lotus Leaf

    Institute of Scientific and Technical Information of China (English)

    CAO Feng; GUAN Zisheng; LI Dongxu

    2008-01-01

    Nano/micro replication,a technique widely applied in the microelectronics field,was introduced to prepare the hydrophobic bionics microstructure on material surface.Poly(vinyl alcohol)(PVA)and polystyrene(PS)moulds of the mastoid microstructure on lotus leaf surface were prepared respectively by the nano/micro replication technology.And poly(dimethylsiloxane)(PDMS)replicas with the mastoid-like microstructure were prepared from these two kinds of polymer moulds.Scanning electronic microscope(SEM) was employed to investigate the morphology and microstructures on moulds and replicas.Both the static and dynamic contact angles between water droplet and PDMS replicas'surface were also measured.As a result,similar microstructure Can be observed clearly on the surface of PDMS replicas and the static contact angle on PDMS replicas was enhanced dramatically by the existence of these microstructures.

  13. Mimicking natural superhydrophobic surfaces and grasping the wetting process: a review on recent progress in preparing superhydrophobic surfaces.

    Science.gov (United States)

    Yan, Y Y; Gao, N; Barthlott, W

    2011-12-12

    A typical superhydrophobic (ultrahydrophobic) surface can repel water droplets from wetting itself, and the contact angle of a water droplet resting on a superhydrophobic surface is greater than 150°, which means extremely low wettability is achievable on superhydrophobic surfaces. Many superhydrophobic surfaces (both manmade and natural) normally exhibit micro- or nanosized roughness as well as hierarchical structure, which somehow can influence the surface's water repellence. As the research into superhydrophobic surfaces goes deeper and wider, it is becoming more important to both academic fields and industrial applications. In this work, the most recent progress in preparing manmade superhydrophobic surfaces through a variety of methodologies, particularly within the past several years, and the fundamental theories of wetting phenomena related to superhydrophobic surfaces are reviewed. We also discuss the perspective of natural superhydrophobic surfaces utilized as mimicking models. The discussion focuses on how the superhydrophobic property is promoted on solid surfaces and emphasizes the effect of surface roughness and structure in particular. This review aims to enable researchers to perceive the inner principles of wetting phenomena and employ suitable methods for creation and modification of superhydrophobic surfaces. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Evaluation of Alternative Peel Ply Surface Preparation Methods of SC-15 Epoxy / Fiberglass Composite Surfaces for Secondary Bonding

    Science.gov (United States)

    2014-01-01

    surface preparation, secondary bonding, peel ply, film adhesive, toughened epoxy, VARTM 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...for the VARTM process. .......................6 Figure 2. Vacuum-bagged laminate during the debulk process...processing temperature. .........................3 Table 2. ARL cure schedule for VARTM processing of SC-15

  15. Preparation of Highly Hydrophobic and Oleophobic Textile Surfaces Using Microwave-Promoted Silane Coupling (Postprint)

    Science.gov (United States)

    2010-12-01

    contact angles of 10 lL water and hexadecane sessile drops were measured on the prepared surfaces using a goniometer (DSA 100, Kruss) at 20 C. The range of...surfaces could provide significant advantages over conventional systems with regard to reducing the time and energy needs associated with conventional...FS does create a hydrophobic and oleophobic surface; however, such pre- treatment provides no discernable advantage over a single base-catalyzed

  16. Preparing soluble aluminum hydroxide by seed precipitation method%种分法制备易溶氢氧化铝的工艺

    Institute of Scientific and Technical Information of China (English)

    晏永祥; 刘少峰; 陈枚燕; 陈启杰

    2013-01-01

    通过种分法制备了易溶氢氧化铝,研究了分解原液浓度、晶种数量和分解温度等实验条件对铝酸钠溶液分解率及氢氧化铝酸溶性的影响.研究结果表明,其最佳条件是:分解初温为40℃,分解终温为30℃,分解原液的Al2O3浓度为130 g/L,晶种数量为0.4 g/L,产品酸溶率在90%以上.并通过SEM和XRD对粒子的形态和晶体结构进行了表征.%The soluble aliminum hydroxide was prepared by seed precipitation method.The effects of decomposition solution concentration,the amount of seed crystal and decomposition temperature on the decomposition rate of the sodium aluminate solution and the aluminum hydroxide acid soluble have been studied.Under the optimum conditions the initial and final decomposition temperature was 40 and 30 ℃,respectively; the decomposition solution concentration of Al2O3 was 130 g/L and the amount of seed crystal was 0.4 g/L,the acid soluble rate of the product was more than 90%.The morphology and crystal structure of the product were characterized by SEM and XRD.

  17. Preparation of Aluminum Nanoparticles/Nitrocellulose Nanofibers%含纳米铝粉的纳米NC纤维的制备

    Institute of Scientific and Technical Information of China (English)

    谢龙; 邵自强; 王文俊; 王飞俊; 王慧庆

    2011-01-01

    In order to overcome the agglomeration of aluminum nanoparticles(AlNPs) in the propellant processing,the smooth and uniform nanofibers of AlNPs/nitrocellulose(NC) have been successfully fabricated by simple adding AlNPs to NC solution before electrospinning.The effect of electrospinning technique on the morphology and diameter of the nitrocellulose nanofibers were investigated by SEM.The suitable electrospinning conditions were as follows: water content, 10 % - 15 %, nitrocellulose solution concentration, 5 % - 10 %, voltage, 25 - 30 kV and extrusion rate,0.5~4 mL/h.The AlNPs/NC nanofibers prepared in the above-mentioned feasible condition reveal that AlNPs distribute uniformly in nanofibers matrix.%为了克服纳米铝粉在推进剂使用过程中分散不均匀的问题,采用静电纺丝技术制备了材料表面光滑、直径均匀、且纳米铝粉分散均匀的纳米NC纤维.用扫描电镜研究了含水率、溶液浓度、电压和挤出速率对纤维形态和直径的影响,得到静电纺丝最佳工艺条件:含水率为10%~15%,NC纺丝液质量分数5%~10%,电压25~30kV,挤出速率0.5~4mL/h.在此工艺条件下,制备出含纳米铝粉的纳米硝化棉纤维,显示纳米铝粉均匀地分散在硝化棉纤维中.

  18. Preparation of electrodes on cfrp composites with low contact resistance comprising laser-based surface pre-treatment

    KAUST Repository

    Almuhammadi, Khaled Hamdan

    2016-12-29

    Various examples are provided related to the preparation of electrodes on carbon fiber reinforced polymer (CFRP) composites with low contact resistance. Laser-based surface preparation can be used for bonding to CFRP composites. In one example, a method includes preparing a pretreated target area on a CFRP composite surface using laser pulsed irradiation and bonding an electrode to exposed fibers in the pretreated target area. The surface preparation can allow the electrode to have a low contact resistance with the CFRP composite.

  19. Wettability of Molten Aluminum-Silicon Alloys on Graphite and Surface Tension of Those Alloys at 1273 K (1000 °C)

    Science.gov (United States)

    Mao, Weiji; Noji, Takayasu; Teshima, Kenichiro; Shinozaki, Nobuya

    2016-06-01

    The wettability of molten aluminum-silicon alloys with silicon contents of 0, 6, 10, and 20 mass pct on graphite substrates by changing the placing sequence of aluminum and silicon and the surface tension of those alloys were investigated at 1273 K (1000 °C) using the sessile drop method under vacuum. The results showed that the wetting was not affected by changing the placing sequence of the Al-Si alloys on the graphite substrates. The wettability was not improved significantly upon increasing the Si content from 0 to 10 mass pct, whereas a notable decrease of 22 deg in the contact angle was observed when increasing the Si content from 10 to 20 mass pct. This was attributed to the transformation of the interfacial reaction product from Al4C3 into SiC, provided the addition of Si to Al was sufficient. It was verified that the liquid Al can wet the SiC substrate very well in nature, which might explain why the occurrence of SiC would improve the wettability of the Al-20 mass pct Si alloy on the graphite substrate. The results also showed that the surface tension values of the molten Al-Si alloys decreased monotonously with an increase in Si content, being 875, 801, 770, and 744 mN/m for molten Al, Al-6 mass pct Si, Al-10 mass pct Si, and Al-20 mass pct Si alloys, respectively.

  20. Morphology observation for surface orange peel and fracture in tension sample of aluminum-alloy sheet and characterization of nano hardness

    Institute of Scientific and Technical Information of China (English)

    Ma Mingtu; Mei Huashen; Lu Hongzhou; Yang Hongya; Wu Emei; Zhou Mingbo

    2012-01-01

    The tension property of aluminum-alloy sheet with different microstructures is measured, and the surface and tension fracture morphology of tension sample with and without orange peel are observed by using scanning electron microscope (SEM). Surface roughness and nano hardness of tension sample are measured. The results show that the average elongation of the samples with orange peel is lower than that without orange peel ; especially the r value of per- pendicular to the rolling direction is much lower than that without orange peel. The tension surface of the orange peel samples is very rough; various parameters of surface roughness are higher. Under the observation of SEM, a wider slid- ing band with a micro crack on the surface of orange peel sample can be found. The various parameters of surface rough- ness without orange peel sample are near to zero, the sliding band is narrow and without micro cracks. The dimple width in tensile fracture of orange peel sample is larger than that without orange peel sample, but shear lip is narrower. The nano hardness testing results show that samples with orange peel behave high elastic modulus, high hardness, and high maximum load, but low plastic deformation depth. These mentioned features can completely describe surface and frac- ture morphology of tension samt31es with oranze peel.

  1. Preliminary Investigation of Aluminum Combustion in Air and Steam.

    Science.gov (United States)

    1983-03-01

    This thesis is prepared in conjunction with research supported in part by Naval Surface Weapons Center under project number N6092183WRW0142...Hallenbeck, Jr. 9. PERPORIING ORGANIZATION NAMC AND ADDRESS . PROGRAM ELEMENT, PROJECT , TASK AREA 6 WORK UNIT NUMMERS Naval Postgraduate School 62633N...using aluminum wire samples which had been accurately weighed. Biomation wave-form traces were made of each test sequence. The Bioma - tion recorder

  2. Degradation processes in Al/SiC{sub p}/MgAl{sub 2}O{sub 4} composites prepared from recycled aluminum with fly ash and rice hull ash

    Energy Technology Data Exchange (ETDEWEB)

    Pech-Canul, M.I.; Escalera-Lozano, R.; Rendon-Angeles, J.C.; Lopez-Cuevas, J. [Cinvestav Saltillo, Carr. Saltillo-Mty. Km. 13, Saltillo, Coah, Mexico 25900 (Mexico); Pech-Canul, M.A. [Cinvestav Merida, Km. 6 Antigua Carr. a Progreso Apdo. Postal 73, Cordemex. Merida, Yuc., Mexico 97310 (Mexico)

    2007-11-15

    The degradation characteristics of Al/SiC{sub p}/spinel composites prepared with fly ash (FA) and rice hull ash (RHA) under environmental conditions were investigated. Composite specimens were prepared with recycled aluminum via reactive infiltration in the temperature range 1050-1150 C for 50-70 min and, in argon atmosphere at a pressure slightly above that of the atmospheric pressure. Results reveal that although both FA and RHA help in preventing SiC{sub p} dissolution and the subsequent chemical degradation of the composites, due to the interaction of native carbon in FA with liquid aluminum, FA-composites are susceptible to corrosion via Al{sub 4}C{sub 3}. Moreover, this phase accelerates the degradation process and increases the damage severity. The primary corrosion mechanism in both types of composites is attributed to microgalvanic coupling between the intermetallic Mg{sub 2}Si and the matrix. Accordingly, an appropriate control of the Si/(Si + Mg) molar ratio in the aluminum alloy hinders the Mg{sub 2}Si corrosion mechanism in both types of composites and a proper FA calcination prevents chemical degradation in FA composites. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  3. Study of preparation and surface morphology of self-ordered nanoporous alumina; Estudo da preparacao e da morfologia de superficie de alumina nanoporosa auto-organizada

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Elisa Marchezini; Martins, Maximiliano Delany, E-mail: elisamarch@gmail.com, E-mail: MG.mdm@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG. (Brazil); Silva, Ronald Arreguy, E-mail: arregsilva@yahoo.com.br [Centro Universitario de Belo Horizonte (UniBH), Belo Horizonte, MG (Brazil)

    2013-07-01

    Nanoporous alumina is a typical material that exhibits self-ordered nanochannels spontaneously organized in hexagonal shape. Produced by anodizing of metallic aluminum, it has been used as a template for production of materials at the nanoscale. This work aimed to study the preparation of nanoporous alumina by anodic anodizing of metallic aluminum substrates. The nanoporous alumina was prepared following the methodology proposed by Masuda and Fukuda (1995), a two-step method consisting of anodizing the aluminum sample in the potentiostatic mode, removing the layer of aluminum oxide (alumina) formed and then repeat the anodization process under the same conditions as the first anodization. This method produces nanoporous alumina with narrow pore diameter distribution and well-ordered structure. (author)

  4. Processing surface sizing starch using oxidation, enzymatic hydrolysis and ultrasonic treatment methods--Preparation and application.

    Science.gov (United States)

    Brenner, Tobias; Kiessler, Birgit; Radosta, Sylvia; Arndt, Tiemo

    2016-03-15

    The surface application of starch is a well-established method for increasing paper strength. In surface sizing, a solution of degraded starch is applied to the paper. Two procedures have proved valuable for starch degradation in the paper mill: enzymatic and thermo-oxidative degradation. The objective of this study was to determine achievable efficiencies of cavitation in preparing degraded starch for surface application on paper. It was found that ultrasonic-assisted starch degradation can provide a starch solution that is suitable for surface sizing. The molecular composition of starch solutions prepared by ultrasonic treatment differed from that of starch solutions degraded by enzymes or by thermo-oxidation. Compared to commercial degradation processes, this resulted in intensified film formation and in greater penetration during surface sizing and ultimately in a higher starch content of the paper. Paper sized with ultrasonically treated starch solutions show the same strength properties compared to commercially sized paper.

  5. Synthesis of AlPO4-5 and CrAPO-5 using aluminum dross.

    Science.gov (United States)

    Kim, Jun; Biswas, Kalidas; Jhon, Ki-Won; Jeong, Soon-Yong; Ahn, Wha-Seung

    2009-09-30

    AlPO(4)-5 and its chromium-containing analogue, CrAPO-5, were prepared using aluminum dross in the presence of triethylamine as a structure directing agent; both Al dross powder and an extracted precipitate from Al dross in an alkali solution were used as an aluminum source. These materials were characterized by XRD, BET surface area measurement, SEM, EDX, XRF, ESR, and UV-vis spectroscopy. Their textural properties were found close to those of the corresponding reference samples prepared using pure Al(OH)(3). CrAPO-5 samples prepared from the aluminum dross were tested as a catalyst for liquid phase oxidation of tetralin using t-butyl hydroperoxide as an oxidizing agent, which showed virtually identical catalytic performances to that obtained by a reference CrAPO-5 catalyst.

  6. Synthetic process for preparation of high surface area electroactive compounds for battery applications

    Energy Technology Data Exchange (ETDEWEB)

    Evenson, Carl; Mackay, Richard

    2013-07-23

    A process is disclosed for the preparation of electroactive cathode compounds useful in lithium-ion batteries, comprising exothermic mixing of low-cost precursors and calcination under appropriate conditions. The exothermic step may be a spontaneous flameless combustion reaction. The disclosed process can be used to prepare any lithium metal phosphate or lithium mixed metal phosphate as a high surface area single phase compound.

  7. Surface mechanical property and residual stress of peened nickel-aluminum bronze determined by in-situ X-ray diffraction

    Science.gov (United States)

    Wang, Chengxi; Jiang, Chuanhai; Zhao, Yuantao; Chen, Ming; Ji, Vincent

    2017-10-01

    As one of the most important surface strengthening method, shot peening is widely used to improve the fatigue and stress corrosion crack resistance of components by introducing the refined microstructure and compressive residual stress in the surface layer. However, the mechanical properties of this thin layer are different from the base metal and are difficult to be characterized by conventional techniques. In this work, a micro uniaxial tensile tester equipped with in-situ X-ray stress analyzer was employed to make it achievable on a nickel-aluminum bronze with shot peening treatment. According to the equivalent stress-strain relationship based on Von Mises stress criterion, the Young's modulus and yield strength of the peened layer were calculated. The results showed that the Young's modulus was the same as the bulk material, and the yield strength corresponding to the permanent plastic strain of 0.2% was increased by 21% after SP. But the fractographic analysis showed that the fracture feature of the surface layer was likely to transform from the dimple to the cleavage, indicating the improved strength might be attained at the expense of ductility. The monotonic and cyclic loading were also performed via the same combined set-up. In addition, the specific relaxation behavior of compressive residual stress was quantified by linear logarithm relationship between residual stress and cycle numbers. It was found that the compressive residual stress mainly relaxed in the first few cycles, and then reached steady state with further cycles. The relaxation rate and the stable value were chiefly depended on the stress amplitude and number of cycles. The retained residual stress kept in compressive under all given applied stress levels, suggesting that the shot peening could introduce a more stable surface layer of compressive residual stress other than the elevated strength of nickel-aluminum bronze alloy.

  8. Implant surface preparation in the surgical treatment of experimental peri-implantitis with autogenous bone graft and ePTFE membrane in cynomolgus monkeys

    DEFF Research Database (Denmark)

    Schou, Søren; Holmstrup, Palle; Jørgensen, Torben

    2003-01-01

    peri-implantitis; treatment; implant surface preparation; nonhuman primates; histology; stereology......peri-implantitis; treatment; implant surface preparation; nonhuman primates; histology; stereology...

  9. Measuring skew in average surface roughness as a function of surface preparation

    Science.gov (United States)

    Stahl, Mark T.

    2015-08-01

    Characterizing surface roughness is important for predicting optical performance. Better measurement of surface roughness reduces polishing time, saves money and allows the science requirements to be better defined. This study characterized statistics of average surface roughness as a function of polishing time. Average surface roughness was measured at 81 locations using a Zygo® white light interferometer at regular intervals during the polishing process. Each data set was fit to a normal and Largest Extreme Value (LEV) distribution; then tested for goodness of fit. We show that the skew in the average data changes as a function of polishing time.

  10. On the Role of Processing Parameters in Producing Recycled Aluminum AA6061 Based Metal Matrix Composite (MMC-AlR) Prepared Using Hot Press Forging (HPF) Process

    Science.gov (United States)

    Ahmad, Azlan; Lajis, Mohd Amri

    2017-01-01

    Solid-state recycling, which involves the direct recycling of scrap metal into bulk material using severe plastic deformation, has emerged as a potential alternative to the conventional remelting and recycling techniques. Hot press forging has been identified as a sustainable direct recycling technique that has fewer steps and maintains excellent material performance. An experimental investigation was conducted to explore the hardness and density of a recycled aluminum-based metal matrix composite by varying operating temperature and holding time. A mixture of recycled aluminum, AA6061, and aluminum oxide were simultaneously heated to 430, 480, and 530 °C and forged for 60, 90, and 120 min. We found a positive increase in microhardness and density for all composites. The hardness increased approximately 33.85%, while density improved by about 15.25% whenever the temperature or the holding time were increased. Based on qualitative analysis, the composite endures substantial plastic deformation due to the presence of hardness properties due to the aluminum oxide embedded in the aluminum matrix. These increases were significantly affected by the operating temperature; the holding time also had a subordinate role in enhancing the metal matrix composite properties. Furthermore, in an effort to curb the shortage of primary resources, this study reviewed the promising performance of secondary resources produced by using recycled aluminum and aluminum oxide as the base matrix and reinforcement constituent, respectively. This study is an outline for machining practitioners and the manufacturing industry to help increase industry sustainability with the aim of preserving the Earth for our community in the future. PMID:28925963

  11. The influence of the base material surface preparation on the properties of thermally sprayed coatings

    Directory of Open Access Journals (Sweden)

    V. Marušić

    2010-01-01

    Full Text Available Using specimens, a research was conducted to determine the influence of the base material surface preparation for 42CrMo4 on the final coating, prior to actual thermal spraying. During thermal spraying, an Al-Ni-alloy was used as an interlayer before the actual coating with Cr-Mo-Ni. The surface hardness and the hardness distribution across the thickness of the sprayed coating were measured and the structure of respective sprayed coatings was photographed. A comparison of experimental results enabled the identification of the particular material preparation method with an optimal ratio of the satisfactory coating thickness and its hardness.

  12. Preparation of quercetin imprinted core-shell organosilicate microspheres using surface imprinting technique

    Institute of Scientific and Technical Information of China (English)

    Peng Yang; Wen Dan Hou; Hong Deng Qiu; Xia Liu; Sheng Xiang Jiang

    2012-01-01

    In this work,the quercetin imprinted core-shell microspheres were prepared using silica surface imprinting technique.A simple sol-gel procedure was used for the synthesis of the imprinted materials with 3-aminopropyltriethoxysilane as functional monomer and tetraethyl orthosilicate as crosslinker.The SEM images indicated that the MIPs shell was successfully grafted onto the silica surface.The characteristics of the molecularly imprinted polymers such as capacity,selectivity and absorption dynamic were investigated by rebinding experiments.The results showed that the prepared MIPs had good imprinting effect and adsorption amount of quercetin.

  13. Aluminum alloy

    Science.gov (United States)

    Blackburn, Linda B. (Inventor); Starke, Edgar A., Jr. (Inventor)

    1989-01-01

    This invention relates to aluminum alloys, particularly to aluminum-copper-lithium alloys containing at least about 0.1 percent by weight of indium as an essential component, which are suitable for applications in aircraft and aerospace vehicles. At least about 0.1 percent by weight of indium is added as an essential component to an alloy which precipitates a T1 phase (Al2CuLi). This addition enhances the nucleation of the precipitate T1 phase, producing a microstructure which provides excellent strength as indicated by Rockwell hardness values and confirmed by standard tensile tests.

  14. Preparation and properties of the SmOx/Rh(100) model surface

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The preparation of SmOx/Rh(100) and CO adsorption on this model surface have been investigated with Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and temperature programmed desorption spectroscopy (TDS). The oxygen adsorption on the SmRh alloy surface leads to the aggregation of Sm on the surface. The thermal treatment of this oxidized surface induces the further agglomeration of SmOx on the Rh(100) surface. Compared with CO TDS on the clean Rh(100) surface, three additional CO desorption peaks can be observed at 176, 331 and 600 K on the SmOx/Rh(100) surface. The CO desorption peak at 176 K may originate from CO adsorbed on SmOx islands, while the appearance of the CO adsorption peaks at 331 and 600 K, depending on the oxidation state of Sm, is attributed to CO species located at the interface of SmOx/Rh(100).

  15. Aluminum Nanoholes for Optical Biosensing

    Directory of Open Access Journals (Sweden)

    Carlos Angulo Barrios

    2015-07-01

    Full Text Available Sub-wavelength diameter holes in thin metal layers can exhibit remarkable optical features that make them highly suitable for (biosensing applications. Either as efficient light scattering centers for surface plasmon excitation or metal-clad optical waveguides, they are able to form strongly localized optical fields that can effectively interact with biomolecules and/or nanoparticles on the nanoscale. As the metal of choice, aluminum exhibits good optical and electrical properties, is easy to manufacture and process and, unlike gold and silver, its low cost makes it very promising for commercial applications. However, aluminum has been scarcely used for biosensing purposes due to corrosion and pitting issues. In this short review, we show our recent achievements on aluminum nanohole platforms for (biosensing. These include a method to circumvent aluminum degradation—which has been successfully applied to the demonstration of aluminum nanohole array (NHA immunosensors based on both, glass and polycarbonate compact discs supports—the use of aluminum nanoholes operating as optical waveguides for synthesizing submicron-sized molecularly imprinted polymers by local photopolymerization, and a technique for fabricating transferable aluminum NHAs onto flexible pressure-sensitive adhesive tapes, which could facilitate the development of a wearable technology based on aluminum NHAs.

  16. Evidências da formação de monocamada de óxido de alumínio sobre sílica, através de reações de enxerto Evidence of aluminum oxide monolayer formation on a silica gel surface using grafting reactions

    Directory of Open Access Journals (Sweden)

    Julia M. D. Cónsul

    2005-06-01

    Full Text Available Aluminum oxide was dispersed on a commercial silica gel surface, using successive grafting reactions. The reaction products were characterized by N2 adsorption-desorption isotherms, scanning electron microscopy and infrared spectroscopy. The progressive incorporation of aluminum, up to 5.5% (w/w, does not produce agglomeration of alumina, since changes in the original pore size distribution of the silica matrix were not observed. The aluminum oxide covers homogeneously the silica surface.

  17. Modeling and Predicting the Effect of Surface Oxidation on the Normal Spectral Emissivity of Aluminum 5052 at 800 K to 910 K

    Science.gov (United States)

    Shi, Deheng; Zou, Fenghui; Zhu, Zunlue; Sun, Jinfeng

    2016-01-01

    In this study, we tried to develop a model to predict the effect of surface oxidization on the normal spectral emissivity of aluminum 5052 at a temperature range of 800 to 910 K and wavelength of 1.5 \\upmu m. In experiments, specimens were heated in air for 6 h at certain temperatures. Two platinum-rhodium thermocouples were symmetrically welded onto the front surface of the specimens near the measuring area for accurate monitoring of the temperature at the specimen surface. The temperatures measured by the two thermocouples had an uncertainty of 1 K. The normal spectral emissivity values were measured over the 6-h heating period at temperatures from 800 K to 910 K in increments of 10 K. Strong oscillations in the normal spectral emissivity were observed at each temperature. These oscillations were determined to form by the interference between the radiation stemming from the oxide layer and radiation from the substrate. The present measurements were compared with previous experimental results, and the variation in the normal spectral emissivity at given temperatures was evaluated. The uncertainty of the normal spectral emissivity caused only by the surface oxidization was found to be approximately 12.1 % to 21.8 %, and the corresponding uncertainty in the temperature caused only by the surface oxidization was approximately 9.1 K to 15.2 K. The model can reproduce the normal spectral emissivity well, including the strong oscillations that occur during the initial heating period.

  18. Utilization of microfluidic V-junction device to prepare surface itraconazole adsorbed nanospheres.

    OpenAIRE

    Kucuk, I.; Ahmad, Z.; Edirisinghe, M.; Orlu-Gul, M.

    2014-01-01

    Itraconazole is widely used as an anti-fungal drug to treat infections. However its poor aqueous solubility results in low bioavailability. The aim of the present study was to improve the drug release profile by preparing surface itraconazole adsorbed polymethylsilsesquioxane (PMSQ) nanospheres using a V-junction microfluidic (VJM) device. In order to generate nanospheres with rough surface, the process flow rate of Perfluorohexane (PFH) was set between 50 and 300 μl min(-1) while the flow ra...

  19. Spatially selective surface platforms for binding fibrinogen prepared by particle lithography with organosilanes

    OpenAIRE

    Englade-Franklin, Lauren E.; Saner, ChaMarra K.; Garno, Jayne C.

    2013-01-01

    We introduce an approach based on particle lithography to prepare spatially selective surface platforms of organosilanes that are suitable for nanoscale studies of protein binding. Particle lithography was applied for patterning fibrinogen, a plasma protein that has a major role in the clotting cascade for blood coagulation and wound healing. Surface nanopatterns of mercaptosilanes were designed as sites for the attachment of fibrinogen within a protein-resistant matrix of 2-[methoxy(polyethy...

  20. Tensile property of Al-Si closed-cell aluminum foam

    Institute of Scientific and Technical Information of China (English)

    YU Hai-jun; YAO Guang-chun; LIU Yi-han

    2006-01-01

    Al-Si closed-cell aluminum foams of different densities were prepared by molten body transitional foaming process. The tensile behavior of Al-Si closed-cell aluminum foam was studied and the influence of relative densities on the tensile strength and elastic modulus was also researched. The results show that the fracture surfaces of Al-Si closed-cell aluminum foam display quasi-cleavage fiacture consisting of brittle cleavages and ductile dimples. The tensile strength and elastic modulus are strictly affected by the relative density of Al-Si closed-cell aluminum foam. With increasing relative density, the tensile strength increases and the strain at which the peak strength is measured also increases; in addition, the elastic modulus increases with increasing relative density.

  1. Selective Adsorption of Sodium Aluminum Fluoride Salts from Molten Aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Leonard S. Aubrey; Christine A. Boyle; Eddie M. Williams; David H. DeYoung; Dawid D. Smith; Feng Chi

    2007-08-16

    Aluminum is produced in electrolytic reduction cells where alumina feedstock is dissolved in molten cryolite (sodium aluminum fluoride) along with aluminum and calcium fluorides. The dissolved alumina is then reduced by electrolysis and the molten aluminum separates to the bottom of the cell. The reduction cell is periodically tapped to remove the molten aluminum. During the tapping process, some of the molten electrolyte (commonly referred as “bath” in the aluminum industry) is carried over with the molten aluminum and into the transfer crucible. The carryover of molten bath into the holding furnace can create significant operational problems in aluminum cast houses. Bath carryover can result in several problems. The most troublesome problem is sodium and calcium pickup in magnesium-bearing alloys. Magnesium alloying additions can result in Mg-Na and Mg-Ca exchange reactions with the molten bath, which results in the undesirable pickup of elemental sodium and calcium. This final report presents the findings of a project to evaluate removal of molten bath using a new and novel micro-porous filter media. The theory of selective adsorption or removal is based on interfacial surface energy differences of molten aluminum and bath on the micro-porous filter structure. This report describes the theory of the selective adsorption-filtration process, the development of suitable micro-porous filter media, and the operational results obtained with a micro-porous bed filtration system. The micro-porous filter media was found to very effectively remove molten sodium aluminum fluoride bath by the selective adsorption-filtration mechanism.

  2. Evaluation of Peel Ply Surface Preparation of Composite Surfaces for Secondary Bonding

    Science.gov (United States)

    2013-09-01

    15 epoxy resin (Applied Poleramic Inc., Benicia, CA) were prepared by the Vacuum Assisted Resin Transfer Molding ( VARTM ) process. Two methods were...viscosity two-phase toughened epoxy resin matrix designed for VARTM processes [8]. The rheological properties of SC-15 have previously been...material system fabricated by the VARTM process ranges between 49 - 52 % with a typical void volume of ~ 1 %, also previously established. Nominal cured

  3. Thin-film preparation by back-surface irradiation pulsed laser deposition using metal powder targets

    Science.gov (United States)

    Kawasaki, Hiroharu; Ohshima, Tamiko; Yagyu, Yoshihito; Ihara, Takeshi; Yamauchi, Makiko; Suda, Yoshiaki

    2017-01-01

    Several kinds of functional thin films were deposited using a new thin-film preparation method named the back-surface irradiation pulsed laser deposition (BIPLD) method. In this BIPLD method, powder targets were used as the film source placed on a transparent target holder, and then a visible-wavelength pulsed laser was irradiated from the holder side to the substrate. Using this new method, titanium oxide and boron nitride thin films were deposited on the silicon substrate. Surface scanning electron microscopy (SEM) images suggest that all of the thin films were deposited on the substrate with some large droplets irrespective of the kind of target used. The deposition rate of the films prepared by using this method was calculated from film thickness and deposition time to be much lower than that of the films prepared by conventional PLD. X-ray diffraction (XRD) measurement results suggest that rutile and anatase TiO2 crystal peaks were formed for the films prepared using the TiO2 rutile powder target. Crystal peaks of hexagonal boron nitride were observed for the films prepared using the boron nitride powder target. The crystallinity of the prepared films was changed by annealing after deposition.

  4. 空调铝箔用高耐水性含氟丙烯酸疏水涂料的研制%Preparation of highly water-resistant fluoroacrylic hydrophobic coating for aluminum foils for air conditioner

    Institute of Scientific and Technical Information of China (English)

    聂建华; 周志盛; 霍泽荣

    2014-01-01

    A fluoroacrylic resin solution was synthesized by radical polymerization based on methyl methacrylate (MMA), butyl acrylate (BA), and stearyl acrylate (SA) as materials with 2-hydroxyethyl methacrylate (HEMA) as hydroxy functional monomer and fluorinated acrylate monomer as organic fluorine modifier, and then blended with curing agent to prepare a hydrophobic coating with high water resistance. The effects of different fluoroacrylate monomers on water contact angle and water dissolution rate of the coating were studied. The influence of the dosages of perfluoroalkyl ethyl methacrylate (PFMA) and HEMA on hydrophobicity and water resistance of the coating was discussed. The optimal reaction formulation was determined as follows: MMA 57%, BA 12%, SA 4%, PFMA 20%, and HEMA 7%. The coating prepared with the optimal formulation was characterized by Fourier transform infrared spectrometry,and tested for comparison of the comprehensive performance with a commercially available product. The results indicated that the coating has a water contact angle 132.7° and a water dissolution rate of 4.1%, being matchable to the comprehensive performance of the superhydrophobic coating formed from the Ultra AC series transparent vanish (a product of the Ultratech Ltd., USA, used for aluminum foils of air conditioner). The coating meets the requirement of surface treatment of aluminum foils for air conditioner.%以甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)以及丙烯酸十八酯(SA)为原料,甲基丙烯酸-β-羟乙酯(HEMA)为羟基功能单体,含氟丙烯酸酯单体为有机氟改性剂,通过溶液自由基聚合反应制备了含氟丙烯酸树脂溶液,再与固化剂配合使用制得高耐水性疏水涂膜。研究了不同含氟丙烯酸酯单体对涂膜的水接触角和水溶率的影响,讨论了甲基丙烯酸全氟烷基乙酯(PFMA)与HEMA不同用量对涂膜的疏水性和耐水性的影响,获得了最佳反应配方:MMA 57%,BA 12%,SA 4%

  5. Friction Surface Morphology and Tribological Property of Copper-Steel-Aluminum Lamellar Composite Materials%层片式复合材料摩擦性能与表面形态的研究

    Institute of Scientific and Technical Information of China (English)

    高飞; 杨亭亭; 符蓉; 韩晓明

    2013-01-01

    粉末冶金材料摩擦面上多组分的混合以及第三体的存在,不利于澄清材料中不同组分对摩擦性能的贡献程度.本文采用机械组合方法制备了铜-钢-铝层片式摩擦材料,通过定速摩擦试验机,在干、湿两种条件下,观察了3种组分的摩擦表面微结构随摩擦速度的变化过程,测试了不同条件下的摩擦性能.结果表明:铜良好的塑性和焊合性,易形成与基体黏附性良好的第三体,使表面的粗糙程度增加;钢较高的强度及其氧化物的脆性,形成的第三体流动性好且与基体的结合强度有限,容易发生开裂和脱落;铝形成的富氧化铝的第三体,其颗粒间较差的黏合程度易在表面弥散分布,使表面平整度好.在摩擦速度低于900 r/min条件下,水分的润滑作用使湿摩擦条件下的摩擦系数低于干摩擦;摩擦速度高于900 r/min时,水分的冷却和清理微细第三体颗粒的作用,降低了材料的软化程度和第三体的流动性,使湿摩擦系数大于干摩擦系数.%The mixture of multi-components and the existence of third-body on the friction surface of powder metallurgy materials make it difficult to clarify the contributions of each components to the tribological property.In this paper,copper-steel-aluminum lamellar friction materials were prepared through mechanical combination.Using a constant-speed tribometer under dry and wet conditions,the changes of friction surface microstructure with respect to friction speed of the three components were investigated,and the tribological property under different conditions was measured.It was found that,the excellent ductility and bondability of copper made it easy to form third body with good bonding to the matrix,resulting in increased surface roughness.The high strength of steel and the brittleness of its oxides led to good flowability of the third body and limited its bonding strength to the matrix,making it easy to crack and spall

  6. Preparation of Nanoelectrode Ensembles by Assembly of Nano- Silver Colloid on Gold Surface

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A novel method for preparing silver nanoelectrode ensembles (SNEEs) and gold nanoelectrode ensembles (GNEEs) has been developed. Silver colloid particles were first absorbed to the gold electrode surface to form a monolayer silver colloid. N-hexadecyl mercaptan was then assembled on the electrode to form a thiol monolayer on which hydrophilic ions cannot be transfered. The SNEEs was prepared by removing thiol from silver colloid surface through applying an AC voltage with increasing frequency at 0.20 V (vs. SCE). Finally, GNEEs was obtained by immersing a SNEEs into 6 mol/L HNO3 to remove the silver colloid particles. By comparison with other methods such as template method etc., this method enjoys some advantages of lower resistance, same diameter, easy preparation, controllable size and density.

  7. Preparation of Nanoelectrode Ensembles by Assembly of Nano—Silver Colloid on Gold Surface

    Institute of Scientific and Technical Information of China (English)

    GangXIA; XiaoYaHU; 等

    2002-01-01

    A novel method for preparing silver nanoelectrode ensembles(SNEEs) and gold nanoelectrode ensembles (GNEEs) has been developed. Silver colloid particles were first absorbed to the gold electrode surface to form a monolayer silver colloid. N-hexadecyl nercaptan was then assembled on the electrode to form a thoil monolayer on which hydrophilic ions cannot be transfered. The SNEEs was prepared by removing thiol from silver colloid surface through applying and AC voltage with increasing frequency at 0.20V(vs.SCE). Finally,GNEEs was obtained by immersing a SNEEs into 6 mol/L HNO3 to remove the silver colloid particles. By comparison with other methods such as template method ect., this method enjoys some advantages of lower resistance, same diameter,easy preparation,controllable size and density.

  8. Preparation and Characterization of Porous Yttrium Oxide Powders with High Specific Surface Area

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The porous cubic yttrium oxides with high specific surface area were prepared by the explosive decomposition of yttrium nitrate and its complex formed with methyl salicylate. The specific surface area and properties of powders synthesized at various temperatures were characterized using BET, X-ray diffraction (XRD), infrared spectra (IR), and scanning electron microscopy (SEM). The results indicate that the highest specific surface area is found to be 65.37 m2*g-1 at the calcination temperature of 600 ℃, and then decreases to 20.33 m2*g-1 with the calcination temperature rising from 600 to 900 ℃. The powders show strong surface activity for adsorping water and carbon dioxide in air, which also decreases with the rising calcination temperature. The drop both on the surface area and surface activity of samples at higher temperatures may be due to pore-narrowing(sintering) effects.

  9. Spatially selective surface platforms for binding fibrinogen prepared by particle lithography with organosilanes.

    Science.gov (United States)

    Englade-Franklin, Lauren E; Saner, Chamarra K; Garno, Jayne C

    2013-06-06

    We introduce an approach based on particle lithography to prepare spatially selective surface platforms of organosilanes that are suitable for nanoscale studies of protein binding. Particle lithography was applied for patterning fibrinogen, a plasma protein that has a major role in the clotting cascade for blood coagulation and wound healing. Surface nanopatterns of mercaptosilanes were designed as sites for the attachment of fibrinogen within a protein-resistant matrix of 2-[methoxy(polyethyleneoxy)propyl] trichlorosilane (PEG-silane). Preparing site-selective surfaces was problematic in our studies, because of the self-reactive properties of PEG-organosilanes. Certain organosilanes presenting hydroxyl head groups will cross react to form mixed surface multi-layers. We developed a clever strategy with particle lithography using masks of silica mesospheres to protect small, discrete regions of the surface from cross reactions. Images acquired with atomic force microscopy (AFM) disclose that fibrinogen attached primarily to the surface areas presenting thiol head groups, which were surrounded by PEG-silane. The activity for binding anti-fibrinogen was further evaluated using ex situ AFM studies, confirming that after immobilization the fibrinogen nanopatterns retained capacity for binding immunoglobulin G. Studies with AFM provide advantages of achieving nanoscale resolution for detecting surface changes during steps of biochemical surface reactions, without requiring chemical modification of proteins or fluorescent labels.

  10. Experimental Investigation of Effect of Process Parameters on Mrr and Surface Roughness In Turning Operation on Conventional Lathe Machine For Aluminum 6082 Grade Material Using Taguchi Method

    Directory of Open Access Journals (Sweden)

    Mihir T. Patel

    2014-01-01

    Full Text Available In this study, the effect of the machining parameters like spindle speed, feed, depth of cut and nose radius on material removal rate and surface roughness are investigated, also optimum process parameters are studied. An L8 orthogonal array (mixed level design, analysis of variance (ANOVA and the signal –to-noise (S/N ratio are used in this study. Mixed levels of machining parameters are used and experiments are done on conventional lathe machine. Aluminum Alloy - Al 6082 grade material is used in high stress applications, Trusses, Bridges, Cranes, Transport applications, Ore skips, Beer barrels, Milk churns etc. The most significant parameters for material removal rate are speed, depth of cut and least significant factor for MRR is nose radius For surface roughness speed, nose radius are the most significant parameters and least significant factor for surface roughness is depth of cut. The mathematical model obtained as a result of regression analysis can be reliable to predict MRR and surface roughness Ra.

  11. Preparation and recognition performance of cytisine alkaloid-imprinted material prepared using novel surface molecular imprinting technique.

    Science.gov (United States)

    Gao, Baojiao; Niu, Qinyuan; Du, Ruikui

    2010-05-01

    Methacrylic acid was first graft-polymerized on the surfaces of micron-sized silica gel particles in the manner of "grafting from" using 3-methacryloxypropyl trimethoxysilane as an intermedia, obtaining the grafted particle polymethacrylic acid PMAA/SiO(2). By adopting the novel surface-molecular imprinting technique put forward by us, cytisine molecule-imprinted material MIP-PMAA/SiO(2) was prepared with ethylene glycol diglycidyl ether as crosslinking agent. The binding characteristics of MIP-PMAA/SiO(2) towards cytisine was investigated in depth with both batch and column methods and using matrine and oxymatrine as two contrast alkaloids, which with cytisine coexist in sophora alopecuroides and their chemical structure is similar to cytisine to a certain extent. The experimental results show that the surface-imprinted material MIP-PMAA/SiO(2) has excellent binding affinity for cytisine (20.1 g/100 g of binding capacity), and it is more important that MIP-PMAA/SiO(2) has very high recognition selectivity for cytisine in relation to the two contrast alkaloids. The selectivity coefficients of the grafted particles PMAA/SiO(2) (non-imprinted material) for cytosine in relation to matrine and oxymatrine are only 1.03 and 1.06, respectively, displaying no recognition selectivity for cytisine. However, after imprinting, the selectivity coefficient of MIP-PMAA/SiO(2) for cytisine in respect to matrine and oxymatrine are remarkably enhanced to 12.08 and 15.05, respectively.

  12. The influence of surface preparation on the absorption coefficient of laser radiation

    Science.gov (United States)

    Kurp, Piotr; Mucha, Zygmunt; Mulczyk, Krystian; Gradoń, Ryszard; Trela, Paweł

    2016-12-01

    The absorption coefficient of the surface of a workpiece is of importance in laser treatment, particularly in the treatment where the temperature of an element must be strictly controlled. Laser surface treatment (such as hardening, metallic glazing) and laser forming can be primarily included in this type of technology. In another case, surface temperature must be precisely controlled, especially if structural changes are to be avoided. There are a number of ways to increase the absorption coefficient of the surface of an element. Since the laser forming is the research subject of the authors of the presented paper, it was necessary to determine the absorption coefficient for the different surfaces preparation of workpieces. Raw surface, oxidized surface, sandblasted surface, black enamel covered surface and waterglass covered surface were examined, respectively. The experiment was performed using a CO2 laser with a head for a surface treatment which generates a rectangular beam of dimensions 2x20 mm, and the samples were made of X5CrNi18-10 stainless steel.

  13. Termination of single-crystal B i2S e3 surfaces prepared by various methods

    Science.gov (United States)

    Zhou, Weimin; Zhu, Haoshan; Yarmoff, Jory A.

    2016-11-01

    Bismuth Selenide (B i2S e3) is a topological insulator with a two-dimensional layered structure that enables clean and well-ordered surfaces to be prepared by cleaving. Although some studies have demonstrated that the cleaved surface is terminated with Se, as expected from the bulk crystal structure, other reports have indicated either a Bi- or mixed-termination. Low-energy ion scattering (LEIS), low energy electron diffraction (LEED) and x-ray photoelectron spectroscopy (XPS) are used here to compare surfaces prepared by ex situ cleaving, in situ cleaving, and ion bombardment and annealing (IBA) in ultrahigh vacuum (UHV). Surfaces prepared by in situ cleaving and IBA are well ordered and Se-terminated. Ex situ cleaved samples could be either Se-terminated or Bi-rich, are less well ordered and have adsorbed contaminants. This suggests that a chemical reaction involving atmospheric contaminants, which may preferentially adsorb at surface defects, could contribute to the nonreproducibility of the termination.

  14. Preparation, Surface and Pore Structure of High Surface Area Activated Carbon Fibers from Bamboo by Steam Activation

    Directory of Open Access Journals (Sweden)

    Xiaojun Ma

    2014-06-01

    Full Text Available High surface area activated carbon fibers (ACF have been prepared from bamboo by steam activation after liquefaction and curing. The influences of activation temperature on the microstructure, surface area and porosity were investigated. The results showed that ACF from bamboo at 850 °C have the maximum iodine and methylene blue adsorption values. Aside from the graphitic carbon, phenolic and carbonyl groups were the predominant functions on the surface of activated carbon fiber from bamboo. The prepared ACF from bamboo were found to be mainly type I of isotherm, but the mesoporosity presented an increasing trend after 700 °C. The surface area and micropore volume of samples, which were determined by application of the Brunauer-Emmett-Teller (BET and t-plot methods, were as high as 2024 m2/g and 0.569 cm3/g, respectively. It was also found that the higher activation temperature produced the more ordered microcrystalline structure of ACF from bamboo.

  15. Preparation and characterization of 3-(triethoxysilyl) propyl isocyanate self-assembled monolayer on surface of chip

    Institute of Scientific and Technical Information of China (English)

    XIE Yao; GENG LiNa; QU Feng; LUO AiQin; QU Feng; DENG YuLin

    2009-01-01

    Monolayer of 3-(triethoxysilyl) propyl isocyanate was prepared on the slide by self-assembled tech-nique. X-ray photoelectron spectroscopy (XPS) was employed to analyze the elementary composition of the film. Contact angle of distilled water was measured to characterize the surface state. It was shown that 3-(triethoxysilyl) propyl isocyanate had been successfully assembled on the slide. The in-crease of contact angle to 80 demonstrated that the hydrophobicity of the surface of chip was in-creased significantly. Moreover, further self-assembly of bovine serum albumin (BSA) on 3-(trietho-xysilyl) propyl isocyanate was also carried out with the advantages such as simple and convenient preparation. Therefore, the potential of broader applications in the modification of micro-channel in the μ-TAS system, the immobilization of protein or peptide and the surface modification of materials are all expectative.

  16. Surface treatment of nickel substrate for the preparation of BSCCO film through sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Yang Huazhe, E-mail: hzyang@mail.cmu.edu.cn [Department of Biophysics, College of Basic Medical Science, China Medical University, Shenyang 110001 (China); Yu Xiaoming [Institute of Materials Physics and Chemistry, School of Sciences, Northeastern University, Shenyang 110819 (China); Ji Yang [Stomatology Department of the General Hospital of Shenyang Military Area Command, Shenyang, 110840 (China); Qi Yang, E-mail: qiyang@imp.neu.edu.cn [Institute of Materials Physics and Chemistry, School of Sciences, Northeastern University, Shenyang 110819 (China)

    2012-03-15

    A modified degreasing-oxidization process was devised and settled to treat the surface of nickel (Ni) substrates, and BSCCO films were prepared on the treated NiO/Ni substrates by sol-gel method. X-ray diffraction (XRD) and optical microscopy were adopted to clarify the function of different treatment on phase formation and wettability of NiO/Ni substrates. Differential thermal analysis and thermal gravimetry analysis were adopted to confirm the desirable heat treatment process. XRD and scanning electron microscopy were adopted to investigate the phase constituent and surface morphology of BSCCO films. Results demonstrate that both the surface wettability of the substrate to sol and the lattice matching between the substrate and BSCCO can be improved through the modified treatment, which are favorable for the preparation of BSCCO films.

  17. All-(111) surface silicon nanowire field effect transistor devices: Effects of surface preparations

    NARCIS (Netherlands)

    Masood, Muhammad Nasir; Carlen, Edwin T.; Berg, van den Albert

    2014-01-01

    Etching/hydrogen termination of All-(111) surface silicon nanowire field effect (SiNW-FET) devices developed by conventional photolithography and plane dependent wet etchings is studied with X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM) and

  18. Preparation and Biocompatible Surface Modification of Redox Altered Cerium Oxide Nanoparticle Promising for Nanobiology and Medicine

    KAUST Repository

    Nanda, Himansu

    2016-11-03

    The biocompatible surface modification of metal oxide nanoparticles via surface functionalization technique has been used as an important tool in nanotechnology and medicine. In this report, we have prepared aqueous dispersible, trivalent metal ion (samarium)-doped cerium oxide nanoparticles (SmCNPs) as model redox altered CNPs of biological relevance. SmCNP surface modified with hydrophilic biocompatible (6-{2-[2-(2-methoxy-ethoxy)-ethoxy]-ethoxy}-hexyl) triethoxysilane (MEEETES) were prepared using ammonia-induced ethylene glycol-assisted precipitation method and were characterized using a variety of complementary characterization techniques. The chemical interaction of functional moieties with the surface of doped nanoparticle was studied using powerful 13C cross polarization magic angle sample spinning nuclear magnetic resonance spectroscopy. The results demonstrated the production of the extremely small size MEEETES surface modified doped nanoparticles with significant reduction in aggregation compared to their unmodified state. Moreover, the functional moieties had strong chemical interaction with the surface of the doped nanoparticles. The biocompatible surface modification using MEEETES should also be extended to several other transition metal ion doped and co-doped CNPs for the production of aqueous dispersible redox altered CNPs that are promising for nanobiology and medicine.

  19. Preparation and Biocompatible Surface Modification of Redox Altered Cerium Oxide Nanoparticle Promising for Nanobiology and Medicine

    Directory of Open Access Journals (Sweden)

    Himansu Sekhar Nanda

    2016-11-01

    Full Text Available The biocompatible surface modification of metal oxide nanoparticles via surface functionalization technique has been used as an important tool in nanotechnology and medicine. In this report, we have prepared aqueous dispersible, trivalent metal ion (samarium-doped cerium oxide nanoparticles (SmCNPs as model redox altered CNPs of biological relevance. SmCNP surface modified with hydrophilic biocompatible (6-{2-[2-(2-methoxy-ethoxy-ethoxy]-ethoxy}-hexyl triethoxysilane (MEEETES were prepared using ammonia-induced ethylene glycol-assisted precipitation method and were characterized using a variety of complementary characterization techniques. The chemical interaction of functional moieties with the surface of doped nanoparticle was studied using powerful 13C cross polarization magic angle sample spinning nuclear magnetic resonance spectroscopy. The results demonstrated the production of the extremely small size MEEETES surface modified doped nanoparticles with significant reduction in aggregation compared to their unmodified state. Moreover, the functional moieties had strong chemical interaction with the surface of the doped nanoparticles. The biocompatible surface modification using MEEETES should also be extended to several other transition metal ion doped and co-doped CNPs for the production of aqueous dispersible redox altered CNPs that are promising for nanobiology and medicine.

  20. Ultrasmooth gold surfaces prepared by chemical mechanical polishing for applications in nanoscience.

    Science.gov (United States)

    Miller, Michael S; Ferrato, Michael-Anthony; Niec, Adrian; Biesinger, Mark C; Carmichael, Tricia Breen

    2014-12-02

    For over 20 years, template stripping has been the best method for preparing ultrasmooth metal surfaces for studies of nanostructures. However, the organic adhesives used in the template stripping method are incompatible with many solvents, limiting the conditions that may subsequently be used to prepare samples; in addition, the film areas that can be reliably prepared are typically limited to ∼1 cm(2). In this article, we present chemical-mechanical polishing (CMP) as an adhesive-free, scalable method of preparing ultrasmooth gold surfaces. In this process, a gold film is first deposited by e-beam evaporation onto a 76-mm-diameter silicon wafer. The CMP process removes ∼4 nm of gold from the tops of the grains comprising the gold film to produce an ultrasmooth gold surface supported on the silicon wafer. We measured root-mean-square (RMS) roughness values using atomic force microscopy of 12 randomly sampled 1 μm × 1 μm areas on the surface of the wafer and repeated the process on 5 different CMP wafers. The average RMS roughness was 3.8 ± 0.5 Å, which is comparable to measured values for template-stripped gold (3.7 ± 0.5 Å). We also compared the use of CMP and template-stripped gold as bottom electrical contacts in molecular electronic junctions formed from n-alkanethiolate self-assembled monolayers as a sensitive test bed to detect differences in the topography of the gold surfaces. We demonstrate that these substrates produce statistically indistinguishable values for the tunneling decay coefficient β, which is highly sensitive to the gold surface topography.

  1. Dye-sensitized solar cells based on nanocrystalline TiO2 films surface treated with Al3+ ions: photovoltage and electron transport studies.

    Science.gov (United States)

    Alarcón, H; Boschloo, G; Mendoza, P; Solis, J L; Hagfeldt, A

    2005-10-06

    Nanocrystalline TiO2 films, surface modified with Al3+, were manufactured by depositing a TiO2 suspension containing small amounts of aluminum nitrate or aluminum chloride onto conducting glass substrates, followed by drying, compression, and finally heating to 530 degrees C. Electrodes prepared with TiO2 nanoparticles coated with less than 0.3 wt % aluminum oxide with respect to TiO2 improved the efficiency of the dye sensitized solar cell. This amount corresponds to less than a monolayer of aluminum oxide. Thus, the Al ions terminate the TiO2 surface rather than form a distinct aluminum oxide layer. The aluminum ion surface treatment affects the solar cell in different ways: the potential of the conduction band is shifted, the electron lifetime is increased, and the electron transport is slower when aluminum ions are present between interconnected TiO2 particles.

  2. Femtosecond Laser Fabricate Wetting FunctionMicro-and Nanostructure on Aerial Aluminum Alloys Surface%飞秒激光制备航空用铝靶材表面润湿功能微纳结构的研究

    Institute of Scientific and Technical Information of China (English)

    吴先福; 白弋枫; 赵洪波; 周文彬; 陶海岩

    2016-01-01

    Over the years,aircraft's wetting function surface anti-icing technology receives much concern because of its many advantages such as not consuming energy and almost no additional volume and quality. Aluminum alloy has been used in civil aircraft widely, especially in shell and skeleton of aircraft. However, the wetting characteristics of original shell's surface don't have an excellent performance. It can effectively change the wetting properties of the surface by femtosecond laser-induced micro- and nanostructures preparation technology. In this paper, we prepared two kinds of typical micro- and nano-multiple structures. Experimental results show that, columnar micro- and nanostructures can achieve the super-hydrophobic surface property caused by the air provided by special double size multi-structure. More-over, trench like micro- and nanostructures make the surface show the super-hydrophilic properties powered by the open cavity capillary effect, and have orientation water delivery function. The realization of these wetting functions has important significance in application for the development of spacecraft anti-icing technology.%近年来,飞行器润湿功能外壳防冰技术以其不消耗能源、几乎不增加额外体积和质量等优点备受世界各国科学家及工程师的关注.铝合金材料一直广泛的应用于民用飞行器,特别是飞机外壳和骨架,然而原有外壳材料表面润湿特性表现中庸.通过飞秒激光微纳结构制备技术,可以有效改变其表面的润湿特性.利用飞秒激光在不同实验条件下,制备了两种典型的微纳复合结构,实验结果表明,柱型微纳结构以独特的双尺寸复合结构所提供的空气气模实现了表面超疏水特性.而沟槽型微纳结构以开放腔毛细管效应为原动力,使其展现了超亲水特性,并具备定向输水功能.这些润湿功能的实现对航空飞行器防冰技术的发展有着重要的应用意义.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-01-25

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

  4. BIOMIMETIC SURFACE PREPARATION OF INERT POLYMER FILMS VIA GRAFTING LONG MONOALKYL CHAIN PHOSPHATIDYLCHOLINE

    Institute of Scientific and Technical Information of China (English)

    Peng-jun Wan; Dong-sheng Tan; Zheng-sheng Li; Xiao-qing Zhang; Jie-hua Li; Hong Tan

    2012-01-01

    To explore construction of novel mimicking biomembrane on biomaterials surfaces,a new polymerizable phosphatidylcholine containing a long monoalkyl chain ended with acryl group (AASOPC) was designed and synthesized,which was easily derived from the terminal amino group of 9-(2-amino-ethylcarbamoyl)-nonyl-l-phosphatidyl-choline (ASOPC) reacting with acryloyl chloride.The obtained AASOPC was grafted on poly(ethylene terephthalate) (PET) via surface-initiated atom-transfer radical polymerization (SI-ATRP) to form mimicking biomembrane.These modified surface structures of PET were investigated using water contact angle (WAC),X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM).The results indicated that the new mimicking phosphatidylcholine biomembrane could be prepared on inert polymer surfaces by using the acryloyl phosphatidylcholine (AASOPC) via surface-initiated atom transfer radical polymerization (SI-ATRP).

  5. Surface Functionality Features of Porous Silicon Prepared and Treated in Different Conditions

    Directory of Open Access Journals (Sweden)

    Yu. M. Spivak

    2016-01-01

    Full Text Available Hydrophilic layers of porous silicon are prepared by single- or two-step anodization and characterized by evaluating their surface hydrophilicity and contents of functional groups using IR spectroscopy and adsorption of acid-base indicators with different pKa values. The surface functional composition of the synthesized samples is shown to be adjustable depending on the anodization current density. The surface of samples obtained at anodization current density 30 mA/cm2 is predominantly occupied with pKa 2.5 corresponding to ≡Si–OH groups. The increase of current density to 80 mA/cm2 results in the increase of surface functional nonuniformity with the formation of versatile centers, primarily Lewis acidic sites corresponding to Si atoms, as indicated by selective indicator adsorption in agreement with the disappearance of Si–H bonds in IR spectra and overall surface disordering according to SEM and AFM data.

  6. Preparation and characterization of chemical gradient surfaces and their application for the study of cellular interaction phenomena

    NARCIS (Netherlands)

    Ruardy, TG; Schakenraad, JM; vanderMei, HC; Busscher, HJ

    1997-01-01

    Chemical gradient surfaces are surfaces with a gradually changing chemistry along their length which is responsible for a position bound variation in physical properties, most notably, the wettability. In this review, methods to prepare (palladium deposition, diffusion technique, density gradient

  7. Surface engineered nanoparticles for improved surface enhanced Raman scattering applications and method for preparing same

    Science.gov (United States)

    Simmons, Blake A.; Talin, Albert Alec

    2009-11-27

    A method for producing metal nanoparticles that when associated with an analyte material will generate an amplified SERS spectrum when the analyte material is illuminated by a light source and a spectrum is recorded. The method for preparing the metal nanoparticles comprises the steps of (i) forming a water-in-oil microemulsion comprising a bulk oil phase, a dilute water phase, and one or more surfactants, wherein the water phase comprises a transition metal ion; (ii) adding an aqueous solution comprising a mild reducing agent to the water-in-oil microemulsion; (iii) stirring the water-in-oil microemulsion and aqueous solution to initiate a reduction reaction resulting in the formation of a fine precipitate dispersed in the water-in-oil microemulsion; and (iv) separating the precipitate from the water-in-oil microemulsion.

  8. Temperature variation on root surface with three root-end cavity preparation techniques

    Directory of Open Access Journals (Sweden)

    Bodrumlu Emre

    2013-01-01

    Full Text Available Introduction. Thermal changes can occur on the external root surface when root-end cavity preparation is performed, which may damage periodontal ligament cells and alveolar bone. Objective. The purpose of this study was to evaluate the temperature changes during preparation of the root-end cavities at 1 and 3 mm to the sectioned apical root surfaces when either tungsten carbide round bur, diamond round bur or ultrasonic diamond tip was used. Methods. Root-end resection was performed at 90° to the long axis of the root, 3 mm from the apex. Specimens were randomly divided into three groups of 12 teeth each for three different root-end cavity preparation techniques to be used, i.e. tungsten carbide bur, diamond bur and ultrasonic diamond retro tip. Thermocouples were used to measure temperature changes at 1 mm (T1 and 3 mm (T2 to the cutting plane during the preparations. Results. For T1, the lowest and the highest mean temperature increases of 3.53°C and 4.34°C were recorded for the carbide and diamond burs, respectively. For T2, the lowest and the highest mean temperature increases of 2.62°C and 4.39°C where recorded for the carbide and diamond burs, respectively. The mean temperatures with the ultrasonic tip were 3.68 and 3.04 ºC at T1 and T2 region, respectively. For root-end preparation, the ultrasonic preparation technique took the shortest preparation time (10.25 sec and the diamond bur took the longest time (28.17 sec. Conclusion. Ultrasonic retro tips and burs caused temperature to rise from 2.62° to 4.39°C, and these rises were within safety levels.

  9. Insights into the superhydrophobicity of metallic surfaces prepared by electrodeposition involving spontaneous adsorption of airborne hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Peng; Cao, Ling; Zhao, Wei; Xia, Yue; Huang, Wei; Li, Zelin, E-mail: lizelin@hunnu.edu.cn

    2015-01-01

    Graphical abstract: - Highlights: • Several superhydrophobic metallic surfaces were fabricated by fast electrodeposition. • Both micro/nanostructures and adsorption of airborne hydrocarbons make contributions. • XPS analyses confirm presence of airborne hydrocarbons on these metallic surfaces. • The adsorption of airborne hydrocarbons on the clean metal Au surface was very quick. • UV-O{sub 3} treatment oxidized the hydrocarbons to hydrophilic oxygen-containing organics. - Abstract: Electrochemical fabrication of micro/nanostructured metallic surfaces with superhydrophobicity has recently aroused great attention. However, the origin still remains unclear why smooth hydrophilic metal surfaces become superhydrophobic by making micro/nanostructures without additional surface modifications. In this work, several superhydrophobic micro/nanostructured metal surfaces were prepared by a facile one-step electrodeposition process, including non-noble and noble metals such as copper, nickel, cadmium, zinc, gold, and palladium with (e.g. Cu) or without (e.g. Au) surface oxide films. We demonstrated by SEM and XPS that both hierarchical micro/nanostructures and spontaneous adsorption of airborne hydrocarbons endowed these surfaces with excellent superhydrophobicity. We revealed by XPS that the adsorption of airborne hydrocarbons at the Ar{sup +}-etched clean Au surface was rather quick, such that organic contamination can hardly be prevented in practical operation of surface wetting investigation. We also confirmed by XPS that ultraviolet-O{sub 3} treatment of the superhydrophobic metal surfaces did not remove the adsorbed hydrocarbons completely, but mainly oxidized them into hydrophilic oxygen-containing organic substances. We hope our findings here shed new light on deeper understanding of superhydrophobicity for micro/nanostructured metal surfaces with and without surface oxide films.

  10. Preparation

    Directory of Open Access Journals (Sweden)

    M.M. Dardir

    2014-03-01

    Full Text Available Some hexanamide-mono and di-linoleniate esters were prepared by the reaction of linolenic acid and hexanamide (derived from the reaction of hexanoic acid and diethanolamine. The chemical structure for the newly prepared hexanamide-mono and di-linoleniate esters were elucidated using elemental analysis, (FTIR, H 1NMR and chemical ionization mass spectra (CI/Ms spectroscopic techniques. The results of the spectroscopic analysis indicated that they were prepared through the right method and they have high purity. The new prepared esters have high biodegradability and lower toxicity (environmentally friendly so they were evaluated as a synthetic-based mud (ester-based mud for oil-well drilling fluids. The evaluation included study of the rheological properties, filtration and thermal properties of the ester based-muds formulated with the newly prepared esters compared to the reference commercial synthetic-based mud.

  11. Surface modification of inorganic layer compound with organic compound and preparation of thin films

    Science.gov (United States)

    Tagaya, Hideyuki; Morioka, Hiroyuki; Ogata, Sumikazu; Karasu, Masa; Kadokawa, Jun-ichi; Chiba, Koji

    1997-11-01

    Water treated Zn/Al layered double hydroxide (LDH) was prepared by the reaction of LDH oxide and water. By the reaction of the water treated Zn/Al LDH or amorphous metal hydroxide and organic oxychloride, surface modified inorganic layer compounds were prepared. Their layer structures were similar to those of the orginal LDHs except the reaction product of amorphous metal hydroxide and benzoyl chloride. Interlayer spacings of the reaction products were 0.77 to 2.67 nm depending on the size and number of function groups of organic compounds.

  12. In vitro study of microleakage of different techniques of surface preparation used in pits and fissures

    Directory of Open Access Journals (Sweden)

    Shahrzad Javadi Nejad

    2012-01-01

    Full Text Available Objective : The purpose of this in vitro study was to evaluate the effect of different techniques of surface preparation on the microleakage of a sealant applied with traditional acid etching and self-etched bonding agent. Study Design : A total of 60 extracted third molars were randomly assigned into six groups (n = 10/each. The occlusal surfaces were sealed with a sealant (Clinpro after one of the following pretreatments: (1 phosphoric acid etching; (2 Prompt L-Pop; (3 laser + etching; (4 laser + Prompt L-Pop; (5 air abrasion + etching; (6 air abrasion + Prompt L-Pop. The specimens were immersed in a 0.5% basic fuchsin solution. Buccolingual cuts parallel to the long axis of the tooth were made. The surfaces were scored 0--2 for extent of microleakage using a microscope and the data were analyzed statistically. Results : The poorest results were obtained with laser + Prompt L-Pop which showed a greater number of specimens with microleakage (80%. Air abrasion surface preparation + phosphoric acid etching showed less microleakage than the other groups (40%. Kruskal--Wallis and t-tests revealed no significant difference in microleakage between six groups. Conclusion : The self-etching adhesive studied seems an attractive alternative to the acid-etch technique for sealant application in young children where simplifications in the clinical procedure are warranted. No significant difference was noted between the different types of enamel preparation before fissure sealant.

  13. Laser surface preparation for adhesive improvement of Ti6Al4V

    Science.gov (United States)

    Loumena, C.; Cherif, M.; Taleb Ali, M.; Jumel, J.; Kling, R.

    2017-02-01

    Titanium alloys are generally noticed for their high specific strength and their good corrosion resistance. They are widely used in light-weight structures especially in the aerospace industry. Surface preparation of Ti6Al4V for bonding improvement is conventionally performed by chemical, electrochemical pre-treatments (chromic acid anodizing, phosphate-fluoride, sol-gel,…) and/or sandblasting in order to modify the morphology and the chemistry of the surface. However, these processes produce a large volume of hazardous chemical or abrasive waste. They require high technical efforts and are therefore economically and environmentally inefficient. Laser processes could lead to a good alternative solution in terms of eco-compatibility, repeatability and ease of manufacturing. In this paper, we report on the latest developments of the collaboration between ALPhANOV and I2M institute on the laser surface preparation for adhesive bonding improvement of Ti6Al4V. We focus our investigations on the effect of pulsed laser irradiation (fluence, scan speed and lateral overlap) with a visible (515 nm) nanosecond "rod-type fibre" laser on the surface morphology and its bonding behaviour (cohesive or adhesive failure). The penetration of the adhesive in the roughness induced by laser irradiation was characterized. For this study, the surfaces were inspected by different means as optical microscopy, 3D profilometer and scanning electron microscopy (SEM). The adhesion performance of the laser treated surface was evaluated by means of DCB tests.

  14. Laser Ablation Surface Preparation of Ti-6A1-4V for Adhesive Bonding

    Science.gov (United States)

    Palmieri, Frank L.; Watson, Kent A.; Morales, Guillermo; Williams, Thomas; Hicks, Robert; Wohl, Christopher J.; Hopkins, John W.; Connell, John W.

    2012-01-01

    Adhesive bonding offers many advantages over mechanical fastening, but requires certification before it can be incorporated in primary structures for commercial aviation without disbond-arrestment features or redundant load paths. Surface preparation is widely recognized as the key step to producing robust and predictable bonds. Laser ablation imparts both topographical and chemical changes to a surface which can lead to increased bond durability. A laser based process provides an alternative to chemical-dip, manual abrasion and grit blast treatments which are expensive, hazardous, polluting, and less precise. This report documents preliminary testing of a surface preparation technique using laser ablation as a replacement for the chemical etch and abrasive processes currently applied to Ti-6Al-4V alloy adherends. Failure mode, surface roughness, and chemical makeup were analyzed using fluorescence enhanced visualization, microscopy, and X-ray photoelectron spectroscopy, respectively. Single lap shear tests were conducted on bonded and aged specimens to observe bond strength retention and failure mode. Some promising results showed increasing strength and durability of lap shear specimens as laser ablation coverage area and beam intensity increased. Chemical analyses showed trends for surface chemical species which correlated with improved bond strength and durability. Combined, these results suggest that laser ablation is a viable process for inclusion with or/and replacement of one or more currently used titanium surface treatments. On-going work will focus on additional mechanical tests to further demonstrate improved bond durability.

  15. Reactive carbon microspheres prepared by surface-grafting 4-(chloromethyl)phenyltrimethoxysilane for preparing molecularly imprinted polymer

    Science.gov (United States)

    Liu, Weifeng; Zhao, Huijun; Yang, Yongzhen; Liu, Xuguang; Xu, Bingshe

    2013-07-01

    Carbon microspheres (CMSs) were oxidized by a mixture of concentrated sulfuric and nitric acids, and modified by 4-(chloromethyl)phenyltrimethoxysilane to give reactive surface. Then, by adopting the surface molecular imprinting technique, dibenzothiophene (DBT) molecule-imprinted material MIP-DBT/CMSs was prepared with methacrylic acid as functional monomer and ethylene glycol dimethacrylate as crosslinking agent. The binding character of MIP-DBT/CMSs toward DBT was investigated with static method by gas chromatography, using fluorene and biphenyl as the reference substances which are similar to DBT in chemical structure to a certain extent. The effects of reaction time, temperature, and coupling agent concentration during silanization were investigated. The results show that the optimized conditions of silanization were 0.3 g oxidized-CMSs, 5% of CMTMS, 80 °C and 4 h. On the basis of silanized-CMSs, MIP-DBT/CMSs was synthesized. The adsorption results show that MIP-DBT/CMSs possessed strong adsorption ability for DBT. The maximal adsorption amount reached up 88.83 mg/g, in comparison with 44.51 mg/g of the non-imprinted polymer. In addition, MIP-DBT/CMSs exhibited a good selective adsorption capacity for DBT than fluorene (19.86 mg/g) and biphenyl (15.33 mg/g). The adsorption behavior followed the pseudo second order kinetic model. And the Freundlich isotherm was found to describe well the equilibrium adsorption data.

  16. Nanoscale surface potential imaging of the photocatalytic TiO2 films on aluminum

    DEFF Research Database (Denmark)

    Daviðsdóttir, Svava; Dirscherl, Kai; Canulescu, Stela

    2013-01-01

    The change in the surface potential of TiO2 coatings upon UV-illumination was investigated on the nanoscale using Scanning Kelvin Probe Force microscopy and on the micro-scale using photo-electrochemical measurements. A good correlation between the two techniques was obtained. The changes...... in the surface potential of TiO2 coatings upon UV-illumination are closely correlated to the band gap and thickness of the coatings. The inhomogeneity surface potential distribution of a 100 nm TiO2 film indicates a heterogeneous coating. Transition to a homogeneous surface potential distribution was observed...... with increasing thickness of the TiO2 coating....

  17. Application of response surface methodology for optimization of azocarmine B removal by heterogeneous photo-Fenton process using hydroxy-iron–aluminum pillared bentonite

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Tianyuan, E-mail: xutianyuan1988@126.com; Liu, Yun, E-mail: liuyunscut@163.com; Ge, Fei, E-mail: gefei@xtu.edu.cn; Liu, Lin, E-mail: liulin861@163.com; Ouyang, Yuting, E-mail: oyt0225@126.com

    2013-09-01

    Hydroxy-iron–aluminum pillared bentonite (H-Fe–Al-B) was synthesized with ion exchange method, and its catalyst characteristics were analyzed by using X-ray diffraction (XRD) and X-ray photoelectron spectrometry (XPS). The photo-Fenton catalytic activity of H-Fe–Al-B was tested under different reaction condition using azocarmine B (ACB) as model pollutant under ultraviolet light (UV) irradiation. The effects of three operating variables, initial dye concentration, initial pH value and H{sub 2}O{sub 2} concentration on the decolorization efficiency of ACB were optimized by response surface methodology (RSM) based on Box–Behnken design. The results showed that hydroxy aluminum iron ions intercalated into the interlayer spaces of bentonite successfully and H-Fe–Al-B had high photocatalytic activity. Analysis of variance (ANOVA) indicated that the proposed quadratic model could be used to navigate the design space. The proposed model was approximately in accordance with the experimental case with correlation coefficients R{sup 2}, R{sub adj}{sup 2} and R{sub pred}{sup 2} correlation coefficients of 0.9996, 0.9991 and 0.9934, respectively. The optimum conditions for ACB decolorization were dye concentration of 143.7 mg/L, pH of 4.2 and H{sub 2}O{sub 2} concentration of 17.7 mM, respectively. The predicted decolorization rate under the optimum conditions determined by the proposed model was 99.6%. Confirmatory tests were carried out under the optimum conditions and the decolorization rate of 99.5% was observed, which closely agreed with the predicted value.

  18. Application of response surface methodology for optimization of azocarmine B removal by heterogeneous photo-Fenton process using hydroxy-iron-aluminum pillared bentonite

    Science.gov (United States)

    Xu, Tianyuan; Liu, Yun; Ge, Fei; Liu, Lin; Ouyang, Yuting

    2013-09-01

    Hydroxy-iron-aluminum pillared bentonite (H-Fe-Al-B) was synthesized with ion exchange method, and its catalyst characteristics were analyzed by using X-ray diffraction (XRD) and X-ray photoelectron spectrometry (XPS). The photo-Fenton catalytic activity of H-Fe-Al-B was tested under different reaction condition using azocarmine B (ACB) as model pollutant under ultraviolet light (UV) irradiation. The effects of three operating variables, initial dye concentration, initial pH value and H2O2 concentration on the decolorization efficiency of ACB were optimized by response surface methodology (RSM) based on Box-Behnken design. The results showed that hydroxy aluminum iron ions intercalated into the interlayer spaces of bentonite successfully and H-Fe-Al-B had high photocatalytic activity. Analysis of variance (ANOVA) indicated that the proposed quadratic model could be used to navigate the design space. The proposed model was approximately in accordance with the experimental case with correlation coefficients R2, Radj2 and Rpred2 correlation coefficients of 0.9996, 0.9991 and 0.9934, respectively. The optimum conditions for ACB decolorization were dye concentration of 143.7 mg/L, pH of 4.2 and H2O2 concentration of 17.7 mM, respectively. The predicted decolorization rate under the optimum conditions determined by the proposed model was 99.6%. Confirmatory tests were carried out under the optimum conditions and the decolorization rate of 99.5% was observed, which closely agreed with the predicted value.

  19. Comparison of linear dimensional change, surface hardness and surface roughness of refractory model prepared from two different duplicating media.

    Science.gov (United States)

    Porwal, Amit; Chandrashekhar, Naveen H; Nadiger, Ramesh K; Meshramkar, Roseline D; Guttal, Satyabodh S

    2011-03-01

    The aim of this study was to evaluate and compare the linear dimensional change, surface hardness and surface roughness of the refractory casts poured against different duplicating media. Polyvinyl siloxane and Agar-agar were used for duplicating the stainless steel die. Sixty refractory models were prepared which were divided into two groups: I and II with 30 samples each respectively. Each group was subdivided into 3 subgroups with 10 samples each which were treated differently. All the specimens were measured for the linear dimensional change and surface hardness and the obtained data was statistically analyzed. Surface roughness was evaluated qualitatively taking SEM photomicrographs. Statistical analysis of linear dimensional change using one-way ANOVA showed statistically significant difference between subgroups of group I and non-significant difference between subgroups of group II. One-way ANOVA for Brinell hardness number showed statistically significant difference between the subgroups of group I & II. Student's 't' test results for linear dimensional change among different subgroups of group I & II showed significant difference between IA-IIA, IB-IIB, IC-IIC. Similarly 't'-test results for Brinell hardness number showed significant difference between subgroups IA-IIA, IB-IIB, and IC-IIC. Surface characteristics of the refractory casts poured against polyvinyl siloxane duplicating media were found to be better than the Agar media.

  20. Designing and preparation of cytisine alkaloid surface-imprinted material and its molecular recognition characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Baojiao, E-mail: gaobaojiao@126.com [Department of Chemical Engineering, North University of China, Taiyuan 030051 (China); Bi, Concon [Department of Chemical Engineering, North University of China, Taiyuan 030051 (China); Fan, Li [School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006 (China)

    2015-03-30

    Highlights: • An elaborate molecular design was well done for molecule surface-imprinting. • The new method of “pre-graft polymerizing and post-imprinting” was used. • Cytisine molecule surface-imprinted material was prepared. • Cytisine surface-imprinting depends on electrostatic interaction between host–guest. • The imprinted material has special recognition selectivity for template cytisine. - Abstract: Based on molecular design, a cytisine surface-imprinted material was prepared using the new surface-imprinting technique of “pre-graft polymerizing and post-imprinting”. The graft-polymerization of glycidyl methacrylate (GMA) on the surfaces of micron-sized silica gel particles was first performed with a surface-initiating system, preparing the grafted particles PGMA/SiO{sub 2}. Subsequently, a polymer reaction, the ring-opening reaction of the epoxy groups of the grafted PGMA, was conducted with sodium 2,4-diaminobenzene sulfonate (SAS) as reagent, resulting in the functional grafted particles SAS-PGMA/SiO{sub 2}. The adsorption of cytisine on SAS-PGMA/SiO{sub 2} particles reached saturation via strong electrostatic interaction between the sulfonate groups of SAS-PGMA/SiO{sub 2} particles and the protonated N atoms in cytisine molecule. Finally, cytisine surface-imprinting was successfully carried out with glutaraldehyde as crosslinker, obtaining cytisine surface-imprinted material MIP-SASP/SiO{sub 2}. The binding and recognition characteristics of MIP-SASP/SiO{sub 2} towards cytisine were investigated in depth. The experimental results show that there is strong electrostatic interaction between particles and cytisine molecules, and on this basis, cytisine surface-imprinting can be smoothly performed. The surface-imprinted MIP-SASP/SiO{sub 2} has special recognition selectivity and excellent binding affinity for cytisine, and the selectivity coefficients of MIP-SASP/SiO{sub 2} particles for cytisine relative to matrine and oxymatrine, which