bluuebunny/crossref_metadata_2025 huggingface dataset:
Cu-Sn Thin Film as Anode for Thin Film Rechargeable Lithium-Ion Batteries
Authors: Polat B. Deniz , Sezgin Nagihan , Keleş Özgul , Kazmanli Kursat , Abouimrane Ali , Amine Khalil
Published: July 2013

We investigated the anode performance of Cu-Sn flat thin film. The results show that the presence of copper improves the cycleability of the thin film since the mechanical tolerance of the thin film against the stress generated during the high volumetric changes in lithiation/delithiation processes is increased. However, some improvement in the microstructure of the thin film is still required to minimize the quantity or the sizes of Sn particles in thin film and facilitate lithium movements in thin film structure.
A Novel Green Approach to Synthesis of Nanostructured Li4Ti5O12 Anode Material
Authors: Chiu Hsien-chieh , Demopoulos George P
Published: July 2013

Li4Ti5O12 (LTO), which is strongly advocated as anode material for lithium ion batteries destined for land transport and grid-integration PV applications, was prepared via a novel low-temperature aqueous synthesis followed by annealing route using only inorganic compounds, including lithium hydroxide and inexpensive titanium tetrachloride as precursors. The synthesis of nanostructured LTO is done via the thermal transformation (annealing) of the aqueous synthesized intermediate phase, Li1.81H0.19Ti2O5·2H2O (LTH). The nanostructure of the prepared LTO material was found to depend on the preceding intermediate phase formation conditions and applied annealing protocol. Thus nanoflower-structured LTO with “petals” 17-50 nm thick was produced by annealing the LTH intermediate phase at 400 oC. However, the morphology changed from flower structure into particulate, when annealing was done at a temperature higher than 500 oC. Finally, after annealing at 700 oC an LTO-rutile TiO2 composite with average particle size of 100 nm was obtained. Possible mechanisms responsible for the different LTO nanocrystal morphologies are proposed.
Characterization of Three-Dimensional Single-Crystalline Porous InP Anodes for Li-Ion Batteries
Authors: Gerngross Mark-Daniel , Quiroga-González Enrique , Carstensen Jürgen , Föll Helmut
Published: July 2013

This paper reports on the electrochemical and photo-(electro)chemical fabrication of a single-crystalline porous InP anode for Li-ion batteries. Additionally, a structural characterization by SEM and XRD as well as a battery characterization by cyclovoltammetry and battery cycling tests in half-cells are presented. This anode exhibits a high capacity per area (~63 mAh/cm2). It consists only of the active material (InP) and a thin Au layer as current collector. The maximum possible capacity of InP (~800 mAh/g) is achieved, which is much higher than the capacity of commercial graphite anodes (~350 mAh/g). The total anode capacity is freely scalable by adjusting the InP membrane thickness.
Rechargeable Lithium-Ion Batteries for Wireless Smart Designs and Extreme Conditions
Authors: Rouault Helene , Mourzagh Djamel , Daniel Lise , Moreau Gilles , Fusalba Florence
Published: July 2013

Wireless communication is today considered as a disruptive technology. Indeed, even if wired systems can easily achieve 100% of reliability, it induces high amount of wiring, which has non negligible impact on the mass and so on the lifetime. In order to save time and planning, wireless communicating sensors appear as a wiring optimization, allowing rapid installation without modification of the general electrical network. But such systems need embedded energy. In order to demonstrate the validity of wireless technology concept adapted to various environments including the space and the aeronautic ones, the developments of miniature & autonomous Li-ion batteries are described in this paper. Their prototypes performances in space, aircraft flights, cold or corrosive environments or under mechanical strains conditions are discussed. They were designed taking into account environment constraints such as temperature (ca. -50°C to 150°C), gravity, vacuum or very low pressure and vibrations. New chemistries for higher energy density, above 250Wh/kg, new components for higher temperatures (close to 100°C) or low temperature operating electrolytes, below -20°C, are also introduced. Learning from this background on smart miniature autonomous systems in extreme conditions and new chemistries for higher autonomy, further developments for larger Li-ion batteries are already started in order to be integrated in air platforms.
Simulation-Based Prediction of Residual Performance of Lithium-Ion Batteries
Authors: Maeda Kazuki , Imamura Wataru , Tanaka Kenji , Akimoto Hiromichi , Horie Hideaki
Published: July 2013

This study proposes a simulation-based evaluation method for lithium-ion batteries (LiB), which enables the estimation of the performance of the battery under different use conditions. In this study, the battery performance is defined as energy density and power density based on users’ needs. The degradation of the battery performance consists of 3 factors, which are capacity fade, an increase in the internal resistance, and the effect of diffusion. With the battery simulator we developed, battery degradation can be simulated by changing three input parameters, each of which corresponding to the degradation factors.Case studies of the evaluation method for aged 18650 cells indicates that aged battery after 1,500 cycles can be used as stationary batteries, but not as batteries for electric vehicles, especially at low temperatures.
Synthesis and Electrochemical Properties of Carbon-Coated Li2FeP2O7 for Li-Ion Batteries
Authors: Saito Morihiro , Yano Sosuke , Maekawa Takuma , Tasaka Akimasa , Inaba Minoru
Published: July 2013

Carbon-coated Li2FeP2O7 (Li2FeP2O7-C) and Mg-doped Li2FeP2O7-C were succeccfully synthesized with pitch as a carbon source and Mg(C2O4)·2H2O as a Mg source, and the charge/discharge properties were compared with that of bare Li2FeP2O7. A thin carbon layer (ca. 5 nm in thickness) was coated on Li2FeP2O7 powder after heat-treatment. Li2FeP2O7-C and Mg-doped Li2FeP2O7-C exhibited high discharge capacities of 97 and 104 mAh g-1, respectively, at C/10 rate, implying a great improvement from that of bare Li2FeP2O7 (69 mAh g-1). The cycleability and rate-capability were also improved by carbon-coating and Mg doping. Mg-doped Li2FeP2O7-C kept a high discharge capacity of 88 mAh g-1 even at 1 C rate. AC impedance analysis revealed that Mg-addition suppresses excess electrolyte decomposition on the surface of Li2FeP2O7 and reduces the resistance of SEI.
Improvement of Tap Density of TiO2(B) Powder as High Potential Negative Electrode
Authors: Nakano Yoshiyuki , Masuda Kanji , Takagi Mikihiro , Saito Morihiro , Tasaka Akimasa , Inaba Minoru
Published: July 2013

The shape and size of TiO2(B) particles were controlled by ball-milling K2Ti4O9, H2Ti4O9 and TiO2(B) powders to improve the tap density of TiO2(B). It was found that only K2Ti4O9 endured the ball-milling process and provided a fine TiO2(B) powder after the ion-exchange and dehydration processes. In contrast, ball-milling of H2Ti4O9 and TiO2(B) powders resulted in a formation of a large amount of the rutile and anatase phase, respectively. In addition, a reduction of the spinning rate to 600 rpm suppressed the formation of the minor impurity of the anatase phase in the TiO2(B) sample prepared from the milled K2Ti4O9 powder. The resulting TiO2(B) (M1-600) powder exhibited a high tap density of 0.71 g cm-3 and a high electrode density of 1.25 g cm-3, which were 2.37 and 1.29 times, respectively, higher than those of the pristine TiO2(B). In charge/discharge tests, M1-600 exhibited a discharge of 213.1 mAh g-1, which is higher than that of the pristine TiO2(B), with a good cycleability. It gave a discharge capacity of 80.1 mAh g-1 even at a high rate of 10 C.
Lithium Intercalation Reaction into Titanium Dioxide Thin Films under UV Irradiation
Authors: Suzuki Shinya , Miyayama Masaru
Published: July 2013

Two types of titanium dioxide thin films were prepared, and their lithium intercalation properties were examined under UV irradiation. Thin films of tetratitanate nanosheets were prepared via electrophoretic deposition. Thin films of TiO2 nanoparticles were obtained by spin-coating a suspension of the nanoparticles, and subsequent heating. Thin films of both tetratitanate nanosheets and TiO2 nanoparticles exhibited a larger capacity on charging under UV irradiation, versus no irradiation. We observed, for the first time, an enhancement in capacity by light irradiation in a lithium ion battery electrode. This enhancement was produced because of an irreversible oxidation reaction induced by UV irradiation in thin films of tetratitanate nanosheets, and as a result of photoconductivity in thin films of TiO2 nanoparticles.
Enlarged Lithium-Ion Migration Pathway by Substitution of B3+ for P5+ in Li3PS4
Authors: Homma Kenji , Yamamoto Tamotsu , Watanabe Satoru , Tanaka Tsutomu
Published: July 2013

A novel composite electrolyte of Li3+3/4x
P1-3/4x
B
x
S4 (0.10 ≤ x ≤ 1.0) was investigated using ac impedance analysis and X-ray diffraction measurement. The highest lithium ionic conductivity at room temperature was 2.2 × 10-4 S·cm-1 at x = 0.35, which is much higher than that ofLi3PS4 (10-7 S·cm-1). The solid solution of Li3+3/4x
P1-3/4x
B
x
S4 (0.10 ≤ x ≤ 1.0) was divided into three crystalline phases: region I, x = (0.10, 0.15); region II, x = (0.20-0.40); and region III, x = (0.60-1.0). The flexion points of the phases corresponded to the flexion points of ionic conductivity data. We compare the triangle window of the lithium migration pathway, of LiS4 and LiS6 polyhedral, for two types of crystal structures: Pmn21(31) and Pnma(62).
FSI-Based Ionic Liquid Electrolyte and Its Specific Effects with Other Component Materials on Li Battery Performance
Authors: Ishikawa Masashi , Yamagata Masaki
Published: July 2013

We evaluated charge-discharge behavior of four graphite electrodes—raw synthetic graphite (SG), shaped natural graphite (NG), soft carbon-coated natural graphite (SCNG), and hard carbon-coated natural graphite (HCNG)—in a 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMImFSI) ionic liquid containing lithium bis(trifluoromethylsulfonyl)imide (LiTFSI). According to charge-discharge curves at the first cycle in LiTFSI/EMImFSI, a capacity loss by an irreversible reaction was observed for cells with SG and SCNG, whereas the capacity loss for cells with NG and HCNG was relatively small. Coulombic efficiency with the cell cycling also proved that charge-discharge behavior of the graphite electrodes in LiTFSI/EMImFSI is strongly affected by surface structure of the graphite active materials and that basal-plane-oriented graphite, such as NG and HCNG, can reduce the loss of primary charge capacity.
Cycle Performance of Lithium-Ion Batteries Containing Ionic Liquids with Improved Reduction Stability
Authors: Itakura Toru , Ito Kyosuke , Yokoi Rie , Ishikawa Jun , Inoue Hiroto , Kadoma Hiroshi , Momo Junpei , Moriwaka Tamae , Nanba Kenryo , Takahashi Minoru , Yamazaki Shunpei
Published: July 2013

The high-temperature cycling performance of lithium-ion batteries containing a new series of ionic liquids based on an aliphatic quaternary ammonium cation and a bis(fluorosulfonyl)amide anion were investigated, by conducting charge-discharge cycling tests of graphite / LiFePO4 cells. The new series of ionic liquids were 1,3-dimethyl-1-propylpiperidinium bis(fluorosulfonyl)amide (3mPP13-FSA) and 7-methyl-5-azoniaspiro[4,5]decane bis(fluorosulfonyl)amide (7mAS45-FSA), which were obtained by introducing methyl groups to known compounds. The relationship between a change in electronic structure and reduction stability was researched. Introducing methyl group improved reduction stability as electron-donating ability. Further, melting points were lowered owing to the asymmetric structures of the cations. The electrochemical properties of these ionic liquids were evaluated by linear sweep voltammetry. The cycle performance of graphite/LiFePO4 cells containing these ionic liquids for the electrolytes was improved compared with that of cells containing organic electrolytes based on LiPF6/ECDEC, and the capacity retention ratios were more than 50% at the 500th cycle at 60°C.
Electrolyte Solvation and Ionic Association: Cyclic Carbonate and Ester-LiTFSI and -LiPF6 Mixtures
Authors: Seo Daniel M. , Allen Joshua Lee , Gardner Lindsay A. , Han Sang-Don , Boyle Paul D. , Henderson Wesley A.
Published: July 2013

Phase diagrams have been prepared for cyclic carbonate and ester mixtures with LiTFSI and LiPF6. A Raman analysis of the mixtures enables the determination of the degree of solvation of the Li+ cations. Key insight into the link between solvent structure and solvation is obtained. It was discovered that the solvent polarity parameters are poor indicators of the molecular-level solvation interactions.
Thermal Phase Behavior and Electrochemical/Physicochemical Properties of Carbonate and Ester Electrolytes with LiBF4, LiDFOB and LiBOB
Authors: Allen Joshua Lee , Seo Daniel M. , McOwen Dennis Wayne , Han Sang-Don , Knight Bradford A. , Boyle Paul D. , Henderson Wesley A.
Published: July 2013

Lithium difluoro(oxalato)borate (LiDFOB) and lithium bis(oxalato)borate (LiBOB) have emerged as superior additives for the formation of favorable passivation layers on active electrodes. In this study, we systematically investigate the thermal phase behavior and electrochemical/physicochemical properties of LiBF4, LiDFOB and LiBOB mixtures with the cyclic carbonate ethylene carbonate (EC) and ester γ-butyrolactone (GBL). Raman spectroscopy was used to determine the degree of solvation that is present in the liquid electrolytes, which may then be directly correlated to the bulk conductivity of the mixtures.
Birth and Death Stochastic Process in Pitting Corrosion and Stress Corrosion Cracking
Authors: Shibata Toshio
Published: July 2013

Random variation in pitting potential and failure time has been successfully analyzed based on the birth and death stochastic approach. On the other hands, the deterministic approach based on the point defect model has succeeded to predict the probability distributions. Similarity and difference of both approaches and the importance of death process or repassivation process in the stochastic approach for pitting corrosion and SCC were discussed.
The Semiconducting Properties and Impedance Analysis of Passive Films on Copper in Anoxic Sulfide-Containing Solutions from the Viewpoint of the Point Defect Model
Authors: Ling Yunhan , Taylor Matthew L. , Sharifiasl Samin , Macdonald Digby D.
Published: July 2013

The corrosion of pure copper in sulfide-containing aqueous solutions that are typical of crystalline rock repositories in Sweden and Finland for the isolation of High Level Nuclear Waste has been studied using potentiostatic and potentiodynamic polarization, Mott-Schottky analysis, and electrochemical impedance spectroscopy. The results, which are interpreted in terms of the Point Defect Model, indicate that a bi-layer sulfide film forms, comprising of a p-type barrier layer of Cu2S and probably an outer layer of CuS, which is n-type in electronic character. The outer layer is not observed to form at 25 oC and at 50 oC, but is observed to form intermittently at 75 oC. Thus, the outer layer is unstable and frequently disappears from the surface by sloughing, resulting in large excursions of the corrosion potential. This phenomenon is found to induce considerable instability in the electrochemical response of the system, such as that under potentiodynamic polarization.
Determining the Coupling Current as a Means of Detecting Crevice Activity and Inhibition
Authors: Lee Sang-Kwon , Kuang Wenjun , Mathews James A. , Macdonald Digby D.
Published: July 2013

A simple crevice corrosion monitor was developed to monitor crevice corrosion in 1018 mild steel, Type 304 SS, and Type 410 SS in DI water and in NaCl solutions with and without the addition of a chemical corrosion inhibitor. The monitor, which measures the electron coupling current, accurately followed the evolution of crevice activity in a manner that can be understood in terms of the cathodic process that occurs on the external surface and the partial anodic process that develops within the crevice, due to the accumulation of H+ and Cl-. The crevice initiation time is typically very short, but appears to depend upon the chloride concentration and possibly on the inhibitor concentration. In addition, amines are effective corrosion inhibitors of crevice corrosion of mild steel and stainless steels in NaCl solutions, provided that they are present in sufficiently high concentrations.
Dielectrostriction and Intergranular Stress Corrosion Cracking of Alloy 600 in PWR Primary Water
Authors: Devine Thomas M.
Published: July 2013

Analysis of six sources of stress in oxides formed along grain boundaries of Alloy 600 in high temperature, pressurized water indicates that dielectrostriction is likely to represent a significant source of tensile stress and can significantly contribute to IGSCC.
Characterization of Repassivation Process on Fe-Cr Alloys Using Scratching Technique
Authors: Wada Masahiro , Kawano Akinori , Saito Minoru , Fujimoto S.
Published: July 2013

Repassivasion is important property of Fe-Cr alloys, since their high corrosion resistance are sustained by passive film that can be broken mechanically or chemically. The roles of cathodic reaction for repassivation process are evaluated by scratching test. In early stage of repassivation, most of the cathodic current is generated by discharge of capacitance in passive film. On the other hand, the discharge current decreased to a relatively low and approaching zero in the late stage, the oxygen reduction reaction largely contributes to cathodic current.
Optimization of Impedance Models with Differential Evolution
Authors: Taylor Matthew Logan , Sharifi Samin , Macdonald Digby D.
Published: July 2013

Impedance models present a set of challenges for traditional curvefitting (model optimization) techniques, especially for “large”impedance functions such as the point defect model. The authors present a new software for optimizing such functions, which employs differential evolution to obtain high quality optimizations of models with dozens of parameters in a reasonalbe amount of time.
Microstructure-Based Numerical Modeling of Pitting Corrosion in 316 Stainless Steel
Authors: Kota Nithyanand , Qidwai Siddiq M. , Lewis Alexis C , DeGiorgi Virginia G.
Published: July 2013

Pitting involves localized corrosion of metals that can result in catastrophic events through crack initiation and failure. Beside the magnitude and mode of loading, the transition from pit to crack is also influenced by the pit shape, which in turn is affected by the microstructure of the corroding material. Thus, predicting the influence of microstructure on pit shape can assist in developing microstructures more resistant to stress corrosion cracking. This work presents numerical modeling of the stable pit growth based on direct incorporation of the actual microstructure in simulations. While many microstructural attributes can contribute towards corrosion, the current work focuses on the effects of the crystallographic orientation of the grains on pit growth through variation in corrosion potential with orientation. Two-dimensional simulation results show the strong influence of the crystallographic orientation on pit shapes and growth under the assumed 5% and 10% variation in corrosion potential, delineating the critical place of crystallographic orientation in pit growth to failure.
Chloride-Induced Stress Corrosion Cracking of Austenitic Stainless Steel Used for Dry Storage of Spent Nuclear Fuel
Authors: Ahn Tae M , Oberson Greg , DePaula Sara
Published: July 2013

Some dry cask storage system (DCSS) designs utilize austenitic stainless steel canisters surrounded by concrete shielding structures to store spent nuclear fuel (SNF) at Independent Spent Fuel Storage Installations (ISFSIs). ISFSIs that are located where chlorides can be deposited on the canisters may have the potential for initiating chloride-induced stress corrosion cracking (SCC). Susceptibility to chloride-induced SCC depends on the environmental conditions at the canister surface, including the following key parameters: temperature; relative humidity (RH); areal density, composition and aqueous concentration of deposited salts; and the stress state of the canister, particularly in the weld and the weld heat affected zone (HAZ). National and international literature was reviewed to understand threshold values and uncertainties associated with these key parameters. Current models have uncertainties associated with salt deposition rate, local humidity and aqueous chemistry on the canister surface, salt composition and water volume, gamma radiolysis, and laboratory test methods.
Electrochemical Characterization of UNS N08367 and UNS S31603 Alloys in Presence of Chloride and Bromide Solutions
Authors: Maya Visuet Enrique , Karayan Ahmad Ivan , Lopez Homero Castaneda
Published: July 2013

This work presents the interfacial characterization of two UNS corrosion resistance alloys (CRAs), N08367 and S31603 in LiCl and LiBr solutions. The electrochemical nature of these materials in halide solutions demonstrates different mechanisms at the substrate-electrolyte interface. Time and frequency domain electrochemical techniques were used; cyclic polarization tests showed that S31603 was attacked by pitting corrosion for different LiCl and LiBr concentrations. N08367 revealed different mechanisms due to the passivation layer existed under polarization conditions. The current densities increments for the N08367 alloy were attributed to the charge transfer-adsorption mechanism, as evidenced by the EIS data. The pitting potentials of S31603 in LiCl and LiBr solutions were similar. However, the current transients were only found in S31603 in LiCl which might indicate that LiCl had more significant kinetic effect than LiBr. Bias potential was applied for EIS testing to support either active/passive/transpassive behavior for each material. Qualitative analysis could demonstrate the link between EIS and polarization techniques.
In Situ Spectroscopic Ellipsometry and Electrochemical Studies of the Barrier Layer on Iron in Borate Buffer Solutions
Authors: Lu Zijie , Sharifiasl Samin , Macdonald Digby D.
Published: July 2013

The growth and properties of the passive films on iron in EDTA (ethylene diamine tetra-acetic acid, disodium salt)-containing borate buffer solution of pH = 8.15 were investigated using in-situ Spectroscopic Ellipsometry (SE), Mott-Schottky analysis, and X-ray photoelectron spectroscopy (XPS). EDTA effectively suppressed the formation of the outer layer of the passive film, thereby rendering the barrier layer amenable to direct examination. It was shown that the barrier layer growth was completed in about 10 s upon stepping the potential in the anodic direction. Contrariwise, thinning of the barrier oxide layer upon stepping the potential in the cathodic direction occurred at a rate that was two orders in magnitude lower than the growth rate. The information obtained above was interpreted in terms of the Point Defect Model (PDM) containing both oxygen vacancies and cation interstitials, with the latter being the dominant defect in the barrier layer.
Monitoring by an Electrochemical Integrated System the Corrosion and Antifouling Treatment on Aluminum Brass Condenser Tubes
Authors: Carvalho Maria Leonor , Cristiani Pierangela , Perboni Giorgio
Published: July 2013

Condenser performance and reliability have a significant impact on the electric generation of a power plant in view of the present energy market. In recent years, the detection of many failure events in condensers drove the achievement of experimental monitoring setup regarding these phenomena. About the formation of protective oxide layers growing on Cu based alloys as Aluminum brass, commonly employed in seawater, the positive role of chlorination treatments and the addition of ferrous ions was addressed. The oxide layer, reinforced with the treatment of ferrous ions, is able to avoid the on-set of localized corrosion phenomena even when seawater becomes of particular aggressiveness, as it happens in presence of high flow with Al brass. Innovative integrated equipment with electrochemical sensors specifically de-signed for industrial application and suitable to monitor the corrosion and biofilm is described.
On the Stability of the Passive Film on Carbon Steel as Indicated by Electrochemical Impedance Spectroscopy
Authors: Urquidi-Macdonald Mirna , Almarzooqi Ahmed , Kursten Bruno , Macdonald Digby D.
Published: July 2013

In this paper, we report an EIS study of the evolution of the passive state of carbon steel in contact with simulated concrete pore water. By mining the impedance data, we have determined that, with time, the defect structure and the defect-dependent properties of the barrier layer of the passive film on iron remain invariant, but that the change in the properties of the passive film, as a whole, can be accounted for in terms of changes in the thickness of the precipitated outer layer. The importance of this finding is that we may apply, with added confidence, the time-independent Point Defect model for describing the barrier layer on carbon steel in contact with concrete pore water over periods of time that are well in excess of experimentally accessible times. Thus, as envisaged in the super-container concept in Belgium’s technology for the disposal of High Level Nuclear Waste (HLNW), the carbon steel over-pack will be exposed to concrete pore water for times exceeding 100,000 years, with the changes in the passive state of the metal being attributed to the increase in thickness of the precipitated, outer layer alone. The rate of formation of the outer layer film at 80 oC is calculated to be 4.6 10-12 cm/s or 1.45 10-4 cm/year = 1.45 ƒÝm/year, which appears to be an eminently reasonable value.
Prediction Model for Atmospheric Stress Corrosion Cracking of Stainless Steel
Authors: Nakayama Gen , Sakakibara Yohei
Published: July 2013

The analyses present the result whereby the initiation lifetime of atmospheric stress corrosion cracking, ASCC is 1.1 years under the following conditions of repair-welded joints: surface residual stress in the axial direction of the welded joints of 362 MPa, residual stress in the thickness of 200 MPa, degree of sensitization, Ra, of 20%, and density of adhesion salt of 0.1 g/m2 [NaCl]. According to the relationship of da/dt-K, it is considered likely that the cracks initiated would penetrate the thickness of 20 mm within 7.6 years or so.
Electrochemical Corrosion Measurements in Supercritical Carbon Dioxide - Water Systems with and Without Membrane Coating
Authors: Beck Justin , Fedkin Mark , Lvov Serguei N.
Published: July 2013

Growing interest in transporting supercritical carbon dioxide (scCO2) for enhanced oil recovery and carbon capture and storage has led to an increased interest in the corrosion behavior of pipeline steels at varying levels of water contamination. While there has already been substantial investigation of aqueous phase corrosion under scCO2 saturation, there has been little to no analysis of the kinetics of the charge transfer process in such environments. Additionally, our group has recently presented a probe for making measurements in the non-conductive scCO2 bulk phase when contaminated by water vapor. This was accomplished by coating the probe tip with an ion conductive membrane, though it was not determined whether the presence of this membrane in any way affected the observed corrosion behavior. The work presented here serves to both increase the knowledge of charge transfer kinetics in water-scCO2 corrosion and examine the influence of ion conductive membranes on the corrosion process.
Investigation of Zinc Dimercaptothiadiazole as a Corrosion Inhibitor for Steel
Authors: Mercado Ramil Marcelo L. , Fury Jonathan , Kiely Michael B. , Buhrmaster Diane , Miller Christopher E. , Zarras Peter
Published: July 2013

The mechanism of corrosion inhibition of zinc dithiomercaptothiadiazole (Zn(DMcT)2) has been known and elucidated. The efficacy of (Zn(DMcT)2) as used in primer coatings for corrosion inhibition on steel alloys such as 1010 steel and 4130 high strength steel under neutral pH conditions was investigated by accelerated corrosion testing methodologies. Solution-state studies and surface elemental analyses were conducted to determine the possible mechanism of corrosion inhibition. Solution state experiments showed a correlation between increasing Zn(DMcT)2 amounts and increased polarization resistance, but DMcT on its own did not show this relationship. Under neutral pH conditions, it was determined that Zn(II) species such as Zn(OH)2, Zn(DMcT)2, and possibly ZnO were deposited on the steel surface, providing corrosion protection.
In Situ Monitoring of Phosphate Inhibitor Surface Deposition during Corrosion of a Zinc Magnesium Aluminium (ZMA) Alloy Using Time-Lapse Microscopy and Energy Dispersive X-ray Spectroscopy
Authors: Mehraban Shahin , Sullivan James H. , Elvins Jon
Published: July 2013

Time-lapse microscopy was used to identify the aqueous corrosion mechanism of a ZMA alloy in-situ using a novel cell. Corrosion was initiated on the alloy using 5% NaCl at pH 3 and sodium phosphate inhibited 5% NaCl was introduced to the cell after a prescribed time. At a concentration of 1x10-4 mol/dm3 no inhibition was observed. A concentration of 1x10-3 mol/dm3 sodium phosphate reduced the rate of anodic growth by a factor of four. 1x10-2 mol/dm3 sodium phosphate produced a cessation of anodic growth over the time period of the experiment. Phosphate deposition was observed at the anodic and cathodic regions of the ZMA alloy. Elevated pH levels at the cathodic sites encouraged stabilisation and increased levels of PO4
3- ions producing an insoluble precipitate of zinc phosphate (Zn3(PO4)2) thus retarding the cathodic reaction. Anodic deposition was thought to be due to locally elevated [Zn2+] and a depletion of free acid leading to zinc phosphate deposition. This novel technique provides a new insight into the mechanism of inhibition at a microstructural level.
Inhibition of Corrosion-Driven Organic Coating Delamination on Hot Dip Galvanized Steel by Phenyl Phosphonic Acid
Authors: Glover Carol F. , Williams Geraint
Published: July 2013

In-coating phenyl phosphonic acid (H2PP) additions are studied to assess their effect on corrosion-driven organic coating disbondment inhibition from a hot-dip galvanized (HDG) steel surface. In-situ scanning Kelvin probe experiments carried out on HDG samples, coated with model polymer organic films containing H2PP at various levels, showed a delay of up to 20 h. The rate of delamination was shown to decrease by up to 94% when compared with a control coating. The observed delamination kinetics suggest an inhibitory mechanism whereby H2PP additions form a cathode-blocking salt layer with the zinc substrate. The possible effects of H2PP, HPP- or PP2- leaching and a buffering of the highly alkaline rendered underfilm pH are also discussed. It is shown that, with increasing levels of in-coating H2PP, the time for delamination kinetics to become established is increased and the delamination rate is substantially decreased.
Oxygen Sensors for Accelerator Driven System (ADS) Reactors
Authors: Verdaguer Ariadna , Colominas Sergi , Abellà Jordi
Published: July 2013

Oxygen activity and its control is an important parameter in the use of molten LBE or lead as a coolant in ADS reactors. Oxygen concentration in the molten alloy should be high enough to form and maintain a stable passivation layer on the surface of the structural material. This layer can minimize the corrosion problems on the structural material. If the oxygen activity drops below a certain level, the passivation layer may decompose and the base metal of the structural material might be exposed to the molten alloy. Nickel, chromium and iron, constitutive elements of stainless steels, show a high solubility in LBE. If the structural material is submerged in molten LBE without a passive oxide layer, it will be dissolved by the action of the molten alloy. Potentiometric sensors for measuring oxygen activity in molten 44.5% lead – 55.5% bismuth alloy have been developed at “Institut Quimic de Sarria” Electrochemistry Lab.
Electrochromic Behavior of Prussian Yellow
Authors: Agrisuelas Jeronimo , Delgado Carla , García-Jareño José J. , Moreno-Guerrero Carmen , Roig Antoni Francesc , Vicente Francisco
Published: July 2013

Prussian Blue films were studied by in situelectrogravimetric and spectroelectrochemical methods during the electrochemical oxidation to the Prussian Yellow form. Spectroelectrochemical studies detected important absorbance changes during electrochemical experiments at 430 nm and 690 nm corresponding to the appearance of the yellow form and to the disappearance of the characteristic blue color. These changes of absorbance were well related with the voltammetric peaks. This redox process has also been studied by in situ electrochemical impedance spectroscopy, mass impedance and color impedance at 690 nm. It has been found that crossed impedance functions obtained from the original ones provide interesting information on the participation of both, cations and anions during electrochemical processes.
Mechanism of Depassivation
Authors: Macdonald Digby D.
Published: July 2013

For more than forty years, the conditions for the existence of the passive state, and hence for the existence of our metals-based civilization, which is based upon the reactive metals (Al, Cr, Fe, Ni, etc), have been described in terms of equilibrium thermodynamics in the form of Pourbaix diagrams. However, Pourbaix diagrams provide an equilibrium view of passivity, whereas passive films are non-equilibrium structures, whose existence depends upon an appropriate relationship between the rate of formation and the rate of destruction. Accordingly, a more accurate and realistic description of the phenomenon of passivity must be found in the field of electrochemical kinetics. This paper presents a kinetic theory for depassivation (loss of passivity), in terms of the relative rates of film growth at the metal/barrier layer interface at zero barrier layer thickness and destruction of the film at the film/solution interface.
Investigation of Pore Diameter Modulation in Depth in p-type Silicon
Authors: Ossei-Wusu Emmanuel , Carstensen Jürgen , Quiroga-González Enrique , Amirmaleki Maedeh , Föll Helmut
Published: July 2013

The possibility of local modulation of the macropore diameter has been investigated for macropores at different pore depths on pre-patterned low-doped p-type silicon (p-Si) substrates. Using electrolytes based on HF/organic solvents, it is relatively easier to vary the diameter of deep pores compared to shallow pores. Adding polyethylene glycol to the electrolyte helps to achieve pore diameter modulation even at shallow depths. Using Fast Fourier Transformation impedance spectroscopy (FFT-IS), the pore growth was analyzed in situ. A simple model was used to fit all the measured data, and some electrochemical parameters could be quantified. Comparing these parameters with the pore morphologies, it was observed that diffusion limitation is essential for achieving pore diameter modulation in p-Si by changing the applied current density.
(Invited) Anodic Dissolution of Si: Electrochemical Oscillations and Porous Silica Formation
Authors: Ozanam Francois , Chazalviel Jean-Noel
Published: July 2013

The behavior of a silicon electrode in fluoride electrolyte is reviewed. Special attention is directed to the electrochemical oscillations observed in the 3-10 V potential range, and to the formation of a mesoporous silica film above 10 V. The oscillatory phenomenon is shown to survive in this high-potential range. The physical mechanisms at the origin of the oscillation are discussed, in light of the various models proposed (stress-induced breakdown vs dielectric breakdown). The model of local oscillators appears as yet as the most suitable one to describe the transition from a resonant behavior to a macroscopic oscillation. Some directions for solving the pending issues are proposed.
Stain Etching of Silicon With and Without the Aid of Metal Catalysts
Authors: Kolasinski Kurt W , Barclay William Brett
Published: July 2013

The development of stain etching relative to anodic etching for theproduction of porous silicon has been hampered by a lack offundamental understanding. By applying Marcus theory we havearrived at a more expansive understanding of the charge transferthat initiates and controls etching. No credible information isavailable on the stoichiometry of stain etchants involving metal ioncontaining oxidants such as VO2+ and Fe3+. Herein we describesuch experiments both for conventional stain etching and metalassisted stain etching in the presence of a pre-deposited catalystsuch as Cu, Ag, Au, Pd or Pt.
(Invited) A Cook's Tour of Two Decades of Research into the Optical Properties of Nanostructured Silicon Materials
Authors: Lockwood David J.
Published: July 2013

Amongst a number of diverse approaches to engineering efficient light emission in silicon nanostructures, one system that has received considerable attention has been Si/SiO2 quantum wells. Engineering such structures has not been easy, because to observe the desired quantum confinement effects, the quantum well thickness has to be less than 5 nm. Nevertheless, such ultra thin structures have now been produced by a variety of techniques. The SiO2 layers are amorphous, but the silicon layers can range from amorphous through nanocrystalline to single-crystal form. The fundamental band gap of the quantum wells has been measured primarily by optical techniques and strong confinement effects have been observed. A detailed comparison is made between theoretical and experimental determinations of the band gap in Si/SiO2 quantum wells. The review article is prefaced with a historical account of the Pits and Pores Symposium series and a personal academic history of the author.
Magnetic Field Assisted Etching of Porous Silicon as a Tool to Enhance Magnetic Characteristics
Authors: Granitzer Petra , Rumpf Klemens , Ohta Toshiyuki , Koshida Nobuyoshi , Poelt Peter , Reissner Michael
Published: July 2013

Porous silicon fabricated by different formation techniques has been utilized as template for the electrodeposition of ferromagnetic metal nanowires within the pores. The porous silicon templates have been prepared by conventional and magnetic field assisted anodization, respectively whereat different morphologies have been obtained. The influence of the morphology of the employed template on the deposited metal structures and as a result on the magnetic properties of the nanocomposites is figured out. Due to a decrease of the pore-diameter, an increase of the smoothness of the deposited nanowires and also because of an increase of the distance between neighbouring ones magnetic crosstalk between them is decreased and results in a modification of the magnetic properties.
Size-Dependent Assessment of Fe3O4-Nanoparticles Loaded into Porous Silicon
Authors: Granitzer Petra , Rumpf Klemens , Tian Yuan , Akkaraju Giri , Coffer Jeffery L. , Poelt Peter , Reissner Michael
Published: July 2013

Iron oxide nanoparticles of different sizes (8, 5 and 3.8 nm) have been infiltrated into the pores of porous silicon matrices, offering a hybrid system with tunable magnetic properties due to the morphology of the matrix, the loading of the nanoparticles and their size. For biomedical applications a superparamagnetic behaviour at room temperature is required, which has been verified for the three particle sizes investigated here. Temperature dependent magnetization measurements show that the blocking temperature is far below room temperature for all three composite systems. Furthermore the toxicity of these composite samples with regard to cell-viability has been investigated. A trypan blue-based dye exclusion test has been used to determine the number of viable cells present in suspensions of HEK 293 cells and resulted in a minimum viability above 90% (by the 5th day) in the case of all three particle sizes infiltrated into the porous Si matrix.
Magnetic Properties of an Iron Oxide/Porous Silicon System Controlled by Magnetic Interactions
Authors: Rumpf Klemens , Granitzer Petra , Poelt Peter , Reissner Michael
Published: July 2013

Magnetite nanoparticles of 8 nm in size have been fabricated by high temperature decomposition with an organic coating of about 2 nm in thickness. These particles are infiltrated into the pores of porous silicon resulting in a hybrid system. For this infiltration process porous silicon with different morphologies is used and the concentration of the iron oxide particle solution has been modified to vary the distance between the particles. These modifications of the particle filling lead to a change of the strength of the magnetic inter-particle coupling within in the pores. In this way the magnetic properties of the system can be controlled, especially the position of the blocking temperature can be shifted.
(Invited) The Effects of Confinement and Coulomb Blockade on the Transport in Ensembles of Si Quantum Dots
Authors: Balberg Isaac
Published: July 2013

In our previous works we tried to provide a framework for the basic transport mechanisms in ensembles of Si quantum dots. In the present work we try to confirm that the quantum confinement and Coulomb blockade are present in the ensembles and to evaluate their effect on the electrical transport in the ensembles. We conclude that the most conspicuous influence of those nano phenomena on the transport is found in the close vicinity of the conductivity percolation threshold of the ensembles. .
XPS Analysis of Porous Silicon
Authors: Aureau Damien , Bouttemy Muriel , Vigneron Jackie , Chazalviel Jean-Noël , Ozanam François , Etcheberry Arnaud
Published: July 2013

This manuscript presents an original XPS study of mesoporous p-type silicon samples. The use of X-ray photoelectron spectroscopy helps in understanding the different chemical environments of silicon atoms generated during porous-silicon formation and their evolution in time. Thus, the oxidation state and the contamination can be precisely known and controlled. The loss of the flatness of the surface is followed by the modification of the plasmon peaks and the morphology obtained is monitored by SEM.
Enhanced Suppression of the Formation of Porous Silicon Based on Secondary Knocked-On Effect in FIB
Authors: Wang Jingjie , Jiao Jiwei , Ge Daohan , Wang Minchang , Liu Wenjun , Xu Jiaqiang
Published: July 2013

In this paper, we report a novel porous silicon (PSi) process to realize controllable micro-to-nano scale features after FIB treatment. It is interested to notice that a “shielding area”, where the etching is enhancedly suppressed, exists around the patterns treated by FIB. This shielding area is ascribed to the secondary knocked-on effect during the FIB process. The diameter of shielding area has positive correlation to the voltage used in the FIB step. Also, the diameter of shielding area decreases when the resistivity of the silicon substrate declines. We achieved a shielding area with width of approximately 4μm on PSi. Typically, a circular feature of PSi with a diameter as large as 10μm is demonstrated for the first time, inside of which dramatically no pore appears at all while outside shielding area remains.
How to Make Single-Crystalline Membranes in Indium Phosphide
Authors: Gerngross Mark-Daniel , Carstensen Jürgen , Föll Helmut
Published: July 2013

This paper reports on the electrochemical and photo-(electro)chemical fabrication of single-crystalline InP membraneswith homogeneous surfaces allowing for adjustable pore shapesfrom square-like to roundish and various surface morphologiesfrom flat to cone-like pore wall tips. It is also possible to keep amesoporous layer on the membrane back side. The InP membranethickness is tunable from several tens of μm to almost 500 μm.
Current-Line Oriented Pore Formation in n-InP Anodized in KOH
Authors: Quill Nathan , Lynch Robert P , O'Dwyer Colm , Buckley Denis Noel
Published: July 2013

Electrochemically formed pores in InP in KOH switch from being crystallographically oriented (CO) to being current-line oriented (CLO) above a specific potential in both 17 mol dm-3 and 2.5 mol dm-3 KOH at a temperature of 10oC. The CLO pores formed in KOH have roughly elliptical cross sections, and are wider along the than along the perpendicular <011> direction. The CLO pores can form only when a critical porosity is reached and their formation marks the transition from porous to planar etching. Many of the features of pore formation are explained by evoking the effect that both temperature and electrolyte concentration can have on the effective diffusion length of holes at the semiconductor-solution interface.
Formation of Self-Organized Nanoporous Anodic Films on Carbon Steel
Authors: Konno Yoshiki , Yang Shu , Tuji Etsushi , Aoki Yoshitaka , Skeldon Peter , Thompson George E. , Habazaki Hiroki
Published: July 2013

The growth behavior of nanoporous anodic films on carbon steel containing 0.213 mass% carbon has been examined during anodizing in ethylene glycol containing 0.1 mol dm-3 NH4F and 0.5 mol dm-3 H2O. The nanopores in the anodic films are generated preferentially along with steps and at “kink-like” sites of the steel surface generated by rf-GD sputtering. The steel contains carbide precipitates with a size of 50-800 nm. The anodic oxide formed on the carbide phase is more chemically soluble during anodizing, producing pits in the anodic films.
Dependence of Current on Porous Layer Structure during Anodization of n-InP in Aqueous KOH Electrolytes
Authors: Lynch Robert P , Quill Nathan , O'Dwyer Colm , Buckley Denis Noel
Published: July 2013

We have performed a computer simulation of the current during anodization of InP in aqueous KOH electrolyte based on the spatial characteristics of the porous structures that are formed. Specifically, we have developed a model, based on the expansion and merging of the porous domains and compared current densities during linear potential sweep and potentiostatic experiments to their respective simulated current-density data. Furthermore, we have compared the expected pore structure at particular stages of etching with corresponding micrographs. From these investigations we are able to demonstrate how the porous structure influences the observed current density.
Transport in Surface Passivated Porous Silicon Membranes
Authors: Kovacs Andras , Kronast Wolfgang , Filbert Alexander , Mescheder Ulrich
Published: July 2013

Permeable porous silicon membranes for ultra- and nanofiltration are realized by combination of microfabrication methods and self-organized nanostructuring. The material properties of native and surface passivated membranes are investigated for different substrate doping and fabrication conditions. Transport mechanisms in the membranes are investigated by permeability measurements for both gases and liquids. A transport model using an electric analog circuit as equivalent model is proposed for simulation of gas transport in nanostructured membranes. Adsorption and desorption isotherms are used to analyze the surface interaction between porous surface and adsorbate. As independent measure, AFM based distance-force measurements have been performed to investigate the adhesion forces as function of the surface properties. The influence of surface passivation on transport processes is evaluated.