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Atsushi Kogo - One of the best experts on this subject based on the ideXlab platform.

Joe H Payer - One of the best experts on this subject based on the ideXlab platform.

  • Devitrification of Fe-Based Amorphous Metal SAM 1651: A Structural and Compositional Study
    Metallurgical and Materials Transactions A, 2009
    Co-Authors: Hung M. Ha, Joe H Payer
    Abstract:

    The effect of heat treatment on the chemistry and structure of an Fe-based bulk Metallic glass (BMG) Fe_48Cr_15Mo_14C_15B_6Y_2 (SAM 1651) was examined experimentally. Chemical segregation was found in the as-received material, with islands 10 to 200 nm in diameter enriched in Y, Mo, and C and depleted in Fe and Cr, with respect to the surrounding matrix. Heat treatment in the range of 600 °C to 800 °C caused partial devitrification of the BMG with the formation of nanocrystalline (Fe, Cr)_23C_6 and (Fe, Cr)_7C_3 carbides in a matrix of the remaining Amorphous phase. The devitrification process followed a primary crystallization route. Amorphous particle-free zones (PFZs) in the devitrified material were found, corresponding to the Y-Mo–rich islands in the fully Amorphous SAM 1651. The formation of Cr-rich carbide during devitrification caused the formation of nanometer-sized Cr-depleted zones surrounding the carbide particles, which is detrimental to the corrosion performance of the alloy after thermal exposure.

  • devitrification of fe based Amorphous Metal sam 1651 and the effect of heat treatment on corrosion behavior
    Journal of The Electrochemical Society, 2009
    Co-Authors: Jason Miller, Joe H Payer
    Abstract:

    Devitrification of Amorphous alloys is a process in which thermodynamically preferable crystalline phases form from the metastable Amorphous phase. The corrosion behavior of the crystalline phases and the remaining Amorphous material is likely to be different from that of the fully Amorphous material and could have detrimental effects on the corrosion resistance of the devitrified material. The effect of heat-treatment on the corrosion behavior of an Fe-based bulk Metallic glass Fe 48 Cr 15 Mo 14 C 15 B 6 Y 2 [structural Amorphous Metal (SAM) 1651] was examined, which revealed a degradation in the corrosion resistance of SAM 1651 upon annealing at 700°C. However, the partially devitrified material still exhibited good corrosion resistance even in the highly aggressive environments of 6 M HCl. The preferential corrosion sites of nanoscale in both fully Amorphous and partially devitrified materials were identified with transmission electron microscope analysis. The corrosion resistance of both fully Amorphous and partially devitrified materials was explained in terms of chemical and structural characteristics of the alloys. © 2009 The Electrochemical Society. [DOI: 10.1149/1.3148325] All rights reserved.

  • corrosion resistance of thermally sprayed high boron iron based Amorphous Metal coatings fe 49 7 cr 17 7 mn 1 9 mo 7 4 w 1 6 b 15 2 c 3 8 si 2 4
    Journal of Materials Research, 2007
    Co-Authors: Joseph C Farmer, J J Haslam, T Lian, P Hailey, J Choi, Raul B Rebak, Nancy Y C Yang, Joe H Payer, J H Perepezko, K Hildal
    Abstract:

    An iron-based Amorphous Metal, Fe 49.7 Cr 17.7 Mn 1.9 Mo 7.4 W 1.6 B 15.2 C 3.8 Si 2.4 (SAM2X5), with very good corrosion resistance has been developed. This material was prepared as a melt-spun ribbon, as well as gas atomized powder and a thermal-spray coating. During electrochemical testing in several environments, including seawater at 90 °C, the passive film stability was found to be comparable to that of high-performance nickel-based alloys and superior to that of stainless steels, based on electrochemical measurements of the passive film breakdown potential and general corrosion rates. This material also performed very well in standard salt fog tests. Chromium (Cr), molybdenum (Mo), and tungsten (W) provided corrosion resistance, and boron (B) enabled glass formation. The high boron content of this particular Amorphous Metal made it an effective neutron absorber and suitable for criticality control applications. This material and its parent alloy maintained corrosion resistance up to the glass transition temperature and remained in the Amorphous state during exposure to relatively high neutron doses.

Henning Sirringhaus - One of the best experts on this subject based on the ideXlab platform.

  • electronic structure of low temperature solution processed Amorphous Metal oxide semiconductors for thin film transistor applications
    Advanced Functional Materials, 2015
    Co-Authors: Josephine Socratous, Kulbinder K Banger, Yana Vaynzof, Aditya Sadhanala, Adam D Brown, Alessandro Sepe, Ullrich Steiner, Henning Sirringhaus
    Abstract:

    The electronic structure of low temperature, solution-processed indium–zinc oxide thin-film transistors is complex and remains insufficiently understood. As commonly observed, high device performance with mobility >1 cm2 V−1 s−1 is achievable after annealing in air above typically 250 °C but performance decreases rapidly when annealing temperatures ≤200 °C are used. Here, the electronic structure of low temperature, solution-processed oxide thin films as a function of annealing temperature and environment using a combination of X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and photothermal deflection spectroscopy is investigated. The drop-off in performance at temperatures ≤200 °C to incomplete conversion of Metal hydroxide species into the fully coordinated oxide is attributed. The effect of an additional vacuum annealing step, which is beneficial if performed for short times at low temperatures, but leads to catastrophic device failure if performed at too high temperatures or for too long is also investigated. Evidence is found that during vacuum annealing, the workfunction increases and a large concentration of sub-bandgap defect states (re)appears. These results demonstrate that good devices can only be achieved in low temperature, solution-processed oxides if a significant concentration of acceptor states below the conduction band minimum is compensated or passivated by shallow hydrogen and oxygen vacancy-induced donor levels.

  • low temperature high performance solution processed Metal oxide thin film transistors formed by a sol gel on chip process
    Nature Materials, 2011
    Co-Authors: Kulbinder K Banger, Yoshihisa Yamashita, Kiyotaka Mori, Rebecca L Peterson, Timothy J Leedham, J Rickard, Henning Sirringhaus
    Abstract:

    A low-temperature, solution-based preparation of Amorphous, Metal oxide semiconducting thin-films is reported. This ‘sol–gel on chip’ hydrolysis approach yields thin-film transistors with high field-effect mobilities, reproducible and stable turn-on voltages and high operational stability.

Curtis P Berlinguette - One of the best experts on this subject based on the ideXlab platform.

  • photodecomposition of Metal nitrate and chloride compounds yields Amorphous Metal oxide films
    Journal of the American Chemical Society, 2017
    Co-Authors: Jingfu He, David M Weekes, Wei Cheng, Kevan E Dettelbach, Aoxue Huang, Tengfei Li, Curtis P Berlinguette
    Abstract:

    UV light is found to trigger the decomposition of MClx or M(NO3)x (where M = Fe, Co, Ni, Cu, or Zn) to form uniform, Amorphous films of Metal oxides. This process does not elevate the temperature of the substrate and thus conformal films can be coated on a range of substrates, including rigid glass and flexible plastic. The formation of the oxide films were confirmed by a combination of powder X-ray diffraction, X-ray photoelectron spectroscopy, X-ray fluorescence spectroscopy, Fourier transform infrared spectroscopy and scanning electron microscopy techniques. Amorphous oxide films of iron, nickel and a combination of iron and nickel demonstrated oxygen evolution reaction electrocatalytic activities commensurate with films of the same compositions prepared by widely used electrodeposition and sputtering methods. These results illuminate a potential route to Amorphous oxides at scale using simple Metal precursors without vacuum or heat.

  • photochemical route for accessing Amorphous Metal oxide materials for water oxidation catalysis
    ChemInform, 2013
    Co-Authors: Rodney D L Smith, Mathieu S Prevot, Randal D Fagan, Pavel A Sedach, Man Kit Jack Siu, Simon Trudel, Zhipan Zhang, Curtis P Berlinguette
    Abstract:

    Photochemical Metal-organic deposition produces Amorphous (mixed) Metal oxide films, which show high electrocatalytic activity for the oxygen evolution reaction.

  • water oxidation catalysis electrocatalytic response to Metal stoichiometry in Amorphous Metal oxide films containing iron cobalt and nickel
    Journal of the American Chemical Society, 2013
    Co-Authors: Rodney D L Smith, Mathieu S Prevot, Randal D Fagan, Simon Trudel, Curtis P Berlinguette
    Abstract:

    Photochemical Metal–organic deposition (PMOD) was used to prepare Amorphous Metal oxide films containing specific concentrations of iron, cobalt, and nickel to study how Metal composition affects heterogeneous electrocatalytic water oxidation. Characterization of the films by energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy confirmed excellent stoichiometric control of each of the 21 complex Metal oxide films investigated. In studying the electrochemical oxidation of water catalyzed by the respective films, it was found that small concentrations of iron produced a significant improvement in Tafel slopes and that cobalt or nickel were critical in lowering the voltage at which catalysis commences. The best catalytic parameters of the series were obtained for the film of composition a-Fe20Ni80. An extrapolation of the electrochemical and XPS data indicates the optimal behavior of this binary film to be a manifestation of iron stabilizing nickel in a higher oxidation level. This work ...

  • photochemical route for accessing Amorphous Metal oxide materials for water oxidation catalysis
    Science, 2013
    Co-Authors: Rodney D L Smith, Mathieu S Prevot, Randal D Fagan, Pavel A Sedach, Man Kit Jack Siu, Simon Trudel, Zhipan Zhang, Curtis P Berlinguette
    Abstract:

    Large-scale electrolysis of water for hydrogen generation requires better catalysts to lower the kinetic barriers associated with the oxygen evolution reaction (OER). Although most OER catalysts are based on crystalline mixed-Metal oxides, high activities can also be achieved with Amorphous phases. Methods for producing Amorphous materials, however, are not typically amenable to mixed-Metal compositions. We demonstrate that a low-temperature process, photochemical Metal-organic deposition, can produce Amorphous (mixed) Metal oxide films for OER catalysis. The films contain a homogeneous distribution of Metals with compositions that can be accurately controlled. The catalytic properties of Amorphous iron oxide prepared with this technique are superior to those of hematite, whereas the catalytic properties of a-Fe100-y-zCoyNizOx are comparable to those of noble Metal oxide catalysts currently used in commercial electrolyzers.

Tsutomu Miyasaka - One of the best experts on this subject based on the ideXlab platform.