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Microstructure And Electrochemical Characteristics Of The Anodic Film Formed On Aluminum Surface, Jeng-Kuei Chang, Chi-Min Liao, Chih-Hsiung Chen, Wen-Ta Tsai

Journal of Electrochemistry

The thickness, morphology, chemical composition, and crystallinity of the anodized film formed on aluminum were examined in a transmission electron microscope (TEM). Thin foil for TEM analysis was prepared by ultramicrotomy. The relationship between the microstructure and the electrochemical characteristics of the alumina film forming on the pure aluminum was discussed in this investigation. At the forming voltage less than 100V, the anodized films formed at 85 ℃in aqueous ammonium adipate electrolyte was amorphous in nature. Although the film resistance was increased with the forming voltage, its dielectric constant was not changed significantly. As the forming voltage exceeded 100V, crystalline …

Cavitation Erosion Behavior Of Ni-Al Intermetallic Coatings, J-T Chang, H-C Yeh, J-L He, K-C Chen

Journal of Electrochemistry

A cathodic arc plasma ion plating process was demonstrated to deposlt deposit Ni-Al film on AISI 1045 carbon steel to evaluate the cavitation protection. Three target materials with Ni₅₂Al₄₈, Ni₆₀Al_4o, and Ni₇₀Al₃₀ compositions were used to reveal the microstructural of coatings. Experimental results show that the nickel content in these deposits increased with the nickel contenof the target material. The major phase of deposited film was NigAl regardless of the target materials. All of the as- deposited films presented very strong adhesion and reflects their cavitation erosion behavior in …

Study Of Marine Biocorrosion Using Afm And Molecular Techniques, Herbert H.P.Fang, Lichong Xu, Tong Zhang

Journal of Electrochemistry

Biofilm is ubiquitous in nature.However,corrosin caused by biofilm is still by and large overlooked. This presentation is to demonstrate the applications of several newly developed analytical techniques in chemisrty and microbiology for the study of marine biocorrosion on steel. AFM(atomic force microscopy) was applied to investigate the initial formation mechanism of biofilm and the degree of corrosion of steel in polluted seawater. DNA/RNA-related molecular techniques were used to analyze the microbial composition corrosive biofilm. Results showed that microbial corrosion began within six days, and the corroded volume in the increased as a power function of time with an index 2.83. …

Metastable Pitting Of Aluminum Anodic Film In Neutral Sodium Chloride Solution, Jing-Mao Zhao, Zhi-Jun Bai, Yu Zuo

Journal of Electrochemistry

Potentiodynamic polarization,electrochemical noise and SEM were used to study the corrosion behavior of L2 aluminum anodic film in 1 mol/L NaCl solutions. The results showed that anodic oxidization of aluminum increases its corrosion resistance greatly. However metastable pits were also observed when the film was thin or was exposed to the solutions for a long time. These pits with a diameter less than 10μm often occurred around the metallic inclusions in film.

Corrosion Behavior Of Reinforcing Steel In Concrete Subjected To Chloride Contamination By Eis, Rong-Gang Hu, Rong-Gui Du, Chang-Jian Lin

Journal of Electrochemistry

Electrochemical impedance spectroscopy(EIS) was employed to study the influence of chloride on the corrosion behavior of reinforcing steel in concrete. In Nyquist plot, the spectrum consists of two semicircles, indicating that the reinforced concrete system contained two time constants,one derived from electrical double layer of reinforcing steel and the other from the deposition film of concrete layer. The depressed semicircle in lower frequency featured the non-faradic behavior of the electrical double layer (EDL) deviated from idea capacitor due to diffusive effect which was attributed to the surface roughness of rebar and the inhomogenity of concrete layer. Then the EDL was …

A Bilayer Self-Assembled Membrane Electrode For Fluorescence And Its Electrochemical Characterization, Xiang-Ying Sun, Bin Liu, Yun-Bao Jiang

Journal of Electrochemistry

The bilayer membrane was assemblied on Au electrode by the electrostatic interaction between the fluorescence regent 1-naphthylamine diacetate acid (NADA) and DL-Cysteine. The SAMs electrode NADA/Cys/Au can be used as fluorescence and electrochemical sensor for metal ions. This paper states the electrochemical characterization of NADA/Cys/Au and SAMs' application in continous determination for Cu²⁺ and Ni²⁺.

Synthesis And Electrochemical Characteristics Of Nickel-Based Complex Oxide LiANi0.78Co0.2Cd0.02O2, Rong-Zhong Yuan, Mei-Zhen Qu, Zuo-Long Yu

Journal of Electrochemistry

The nickel-based complex oxide Li_aNi_0.78Co_0.02O₂ cathode materials for lithium-ion rechargeable batteries was synthesized by the improved solid-state reaction method with LiOH·H₂O, ball-like Cd-doped Ni(OH)₂ and Co₂O₃ as raw materials. The analysis ICP-AES proved that the as-prepared compounds were near the stoichiometric form. The XRD, SEM and electrochemical characteristics testing were also carried out. The results showed that the complex cathode material Li_aNi_0.78Co_0.2Cd_0.02O₂ has layered structure, homogeneous surface distributions,uniform particles with good crystal morphology as well as stable electrochemical …

Perfluorinated Sulfonic Acid Lithium Conductivity Humidity Sensor, Hong-Feng Xu, Jing Liu, Li Wan

Journal of Electrochemistry

Treat carbon paper with 3% PTFE solution and dried in 340 ℃ for 40 minutes to enhance its intension, and level off the surface of the carbon paper with a mixture of XC-72 carbon black and PTFE solution. With those treated carbon paper as electrodes, recast Nafion thin film from 5% Nafion solution as humidity sensitive material, a solid polymer electrolyte humidity sensor was prepared on a thin PET film. Take the relative humidity data from several saturated salt solutions, the relationship between conductivity response and relative humidity was studied at different relative humidies .The results showed: when the polymer …

The Electrochemical Behaviors Of A Novel Ferrocene Alkylthiol Sams On Au Electrode, Xiao-Gang Zhang, Yan-Li Shi, Hu-Lin Li

Journal of Electrochemistry

A novel alkylthiol molecule containing ferrocene and pyridium moieties and its hydrogenated products were synthesized and subsequently assembled on Au electrode as SAMs. Cyclic voltammogram(CV) was used to investigate the structure-dependent electrochemical response of the SAMs in 0.1 mol/L HClO₄ aqueous solution.

Effect Of Scn- On The Transition Current Of Zn During The Electrodeposition Zn-Co Alloys, Ren-He Yin, Wei-Min Cao, Zheng-Hua Fang

Journal of Electrochemistry

For co-deposition of Zn-Co alloys at sufphate baths with micro-concentration of SCN^- the transition current of Zn was found with the deposition process changing from normal Co-deposition to anomalous co-deposition, and the value of transition current increased with increasing SCN^- concentration, but decreased with increasing value of pH. The existence of SCN^- decreases the evolution overpotential of Co metal, but has no effects on the evolution overpotential of Zn metal and H₂.

Electrochemical Monitoring On The Deactivation Of A Metallic Oxide Anode, Li-Kun Xu, Shi-Zhe Song, Ting-Yong Wang, Guang-Zhang Chen

Journal of Electrochemistry

The process of accelerated life test of an IrO₂/Ta₂O₅ coated titanium anode was monitored using cyclic voltammetry and electrochemical impedance spectroscopy. The vatiation with electrolysis time of anodic voltammetric charge Q^*, the double layer capacitance C_dl,the oxide film resistance R_f and the charge transfer resistance R_ct for oxygen evolution was measured. A deactivation mechanism was proposed based on the observation results.

Corrosion Prediction Of Carbon Steel In Concentrated Lithium Bromide Solutions At High Temperature Using Bp Neural Network, Nai-Bao Huang, Cheng-Hao Liang

Journal of Electrochemistry

Neutral network model has been developed for the computation of corrosion rate of carbon steel in LiBr solutions.The results indicate that the model is capable of reproducing the effects of changes in alkalinity, temperatures, LiBr and Na₂MoO₄ concentrations on the rates of general corrsion and good agreement between calculated and experimental corrosion rate is obtained. The model can be used to satisfactorily predict the corrosion rate of carbon steel in different concentrations of LiBr solutions containing different inhibitors at different temperatures. It also provides a novel method for corrosion monitoring of metals used in LiBr absorption chiller.

Recent Progress In The Research On Electrodeposition Of Composite Coatings, Xiao-Bing Liu, Xu-Cheng Wang, Yu Chen, Dan-Hong Cheng, Zu-Zhan Yu

Journal of Electrochemistry

Recent progress in the research on composite coatings prepared by electroplating technology is reviewed. The nanoscaled particles, electrocatalytic, photoactive composite coatings are emphatically discussed. The composite coatings prepared by dispersing nanoscaled particles could attain better hardness, wear resistance and corrosion resistance than those of composite coatings which prepared by adding micronscaled particles. As compared with pure metal electrode and alloy electrode, some electrocatalytic composite coatings electrode could markedly reduce the overvoltages of cathodic and anodic electrode reaction. In recent years, the electrocatalytic composite coatings which based on metal oxides and conductive polymer as matrix materials become a newest field of …

Oxidation Behavior Of Zr-Cu-Al-Ni Amorphous Alloys In Air At 300～500℃, H. H. Hsieh, W. Kai, T. G. Neih, Y. Kawamura

Journal of Electrochemistry

The oxidation behavior of the Zr- based bulk amorphous alloy (BMG; Zr-30Cu-10Al-5Ni in at.%) was studied in dry air over the temperature range 300～500 ℃. The kinetic results indicated that the amorphous alloy oxidized linearly at 300 ℃, while the parabolic oxidation was observed at 350～425 ℃, and the oxidation behavior at 500 ℃ was irregular and complicated. In general, the scales formed on the surface of the amorphous alloy were temperature-dependent, consisting of tetragonal-ZrO₂ at 300 ℃, and of mostly tetragonal-ZrO₂ as well as minor amounts of monoclinic-ZrO₂ and CuO at T ≥ 350 ℃.

Selective Corrosion In Duplex Stainless Steel, Wen-Ta Tsai, Kuen-Ming Tsai, Chang-Jian Lin, Yan Fu

Journal of Electrochemistry

In duplex stainless steel, the two constituent phases, namely ferritic (α) and austenitic (γ) phases, have different crystal structure and chemical composition. They may thus exhibit different corrosion resistances in aqueous environment. In this investigation, an electrochemical technique with spatial resolution was employed to measure the potential difference between these two constituent phases in 2205 duplex stainless steel. Image analyzing techniques were also used to examine the preferential corrosion between α and γ phases. The experimental results showed that ferrite had a higher potential than austenite in 0.01 mol/L NaCl solution. In 2 mol/L H₂SO₄+x mol/L …

Corrosion Behavior Of Mg1.85Mm0.15Ni Hydrogen Storage Alloy Modified By Electroless Cu In Ch3Ohâ·H2O Solutions, Hua-Bin Yang, Hai-Chang Zhang, Hua Sun, Xiao-Dan Wang, Zuo-Xiang Zhou

Journal of Electrochemistry

The corrosion behavior of the Mg_1.85Mm_0.15Ni (Mm:Ce-rich mischmetal) alloy modified by electroless Cu coating in different CH₃OH-H₂O solutions has been investigated by potentiodynamic polarization and electrochemical impedance spectroscopy. These results showed that the corrosion behavior was improved after electroless Cu. The potentiodynamic polarization and electrochemical impedance spectroscopy results showed that the alloy electrode had more promising anti-corrosion behavior after coated in a 40%CH₃OH-H₂O solution. The values of corrosion current density and electrode reaction resistance were 5.6 mA·cm^-2 (11.7 mA·cm^-2 for uncoated alloy electrode) and 22.25 Ω·cm …

Conductance Properties For Electrolyte Of Lithium Ion Battery At Low Temperature, Jing-Li Han, Yan-Mei Yu, Jian Chen, Chun-Tong Wang

Journal of Electrochemistry

The system of LiPF₆-ethylene carbonate (EC)-methy1 acetate (MA) was studied. The conductivities of this system were measured under various composition and various salt concentrations at temperature range of 20～-50 ℃. The optimum composition of this system was selected. The tests of cyclic voltammography and charge-discharge were carried out. This system was compared with commercial electrolyte solution.

Synthesis Of Tin Oxide Nanocrystalline Phases Via Use Of Tin (Ii) Halide Precursors, Hongmei Deng, Frank K. Lamelas, Jeanne Hossenlopp

Chemistry Faculty Research and Publications

Nanocrystalline tin oxides are synthesized via precipitation from heated solutions as well as from a novel above-solution vapor deposition route that occurs at low temperatures and atmospheric pressure. Crystalline phases are characterized via powder X-ray diffraction. Samples precipitated from reactions of SnCl2 are found to exist primarily as mixtures of tetragonal SnO and tetragonal SnO2 or tetragonal SnO2 and tin(II) oxyhydroxide (Sn6O4- (OH)4), depending on reaction conditions. A mixed tin(II)/tin(IV) sample is shown to produce a rarely observed form of the intermediate oxide Sn3O4 upon annealing in air at 600 °C. SnBr2 exclusively forms tetragonal SnO2 via precipitation. Variation in …

Development Of A Systems Engineering Model Of The Chemical Separations Process, Yitung Chen, Darrell Pepper, Randy Clarksean

Separations Campaign (TRP)

Two activities are proposed: the development of a systems engineering model and the refinement of the Argonne code AMUSE (Argonne Model for Universal Solvent Extraction). The detailed systems engineering model will be continuously focusing on the integrated approach to the analysis of the materials separations associated with the TRP Program. A second portion of the project will streamline and improve an integral part of the overall systems model, which is the software package AMUSE. AMUSE analyzes the UREX process and other related solvent extraction processes and defines many of the process streams that are integral to the systems engineering model. …

Development Of A Systems Engineering Model Of The Chemical Separations Process: Quarterly Progress Report 2/16/03- 5/15/03, Yitung Chen, Randy Clarksean, Darrell Pepper

Separations Campaign (TRP)

Two activities are proposed in this Phase I task: the development of a systems engineering model and the refinement of the Argonne code AMUSE (Argonne Model for Universal Solvent Extraction). The detailed systems engineering model is the start of an integrated approach to the analysis of the materials separations associated with the AAA Program. A second portion of the project is to streamline and improve an integral part of the overall systems model, which is the software package AMUSE. AMUSE analyzes the UREX process and other related solvent extraction processes and defines many of the process streams that are integral …

Asymmetric Transfer Hydrogenation Of Allylic Alcohols, Joseph M. Laquidara

Seton Hall University Dissertations and Theses (ETDs)

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Solvent And Method For Extraction Of Triglyceride Rich Oil, Shubhender Kapila, Paul Ki-Souk Nam, V. J. Flanigan

Chemistry Faculty Research & Creative Works

The present invention relates to a solvent for use in extracting oil from an oil bearing material, such as soybeans, with the solvent resulting in the selective extraction of a triglyceride rich oil, which contains 95% or greater triglycerides and non-polar constituents, with the solvent comprised of a hydrocarbon, preferably hexane, and a fluorocarbon, so that the solvent has a viscosity less than 2.6 centipoise and a polarity of less than 0.1. The present invention also relates to a method of using the solvent to extract the triglyceride rich oil, with the method including preferably extracting the oil at a …

Chemistry & Biochemistry Newsletter, Department Of Chemistry & Biochemistry, South Dakota State University

Chemistry & Biochemistry Newsletter: 2002-2015

Inside:

Page 2 2003 Graduates; Bonneman Scholarship in Medical Technology Awarded; Dean’s List–Spring 2003

Page 3 Update of Sophomore Organic Chemistry Lab; Halaweish Receives Governor’s Grant

Page 4 A Mini-sized Antarctic in Shepard Hall

Page 5 Alumni News; Faculty and Staff News; Foundation Donors

Page 6 Recent Faculty Publications

Stress Corrosion Cracking Of Type 422 Stainless Steel For Applications In Spallation-Neutron-Target Systems, Ramprashad Prabhakaran

Transmutation Sciences Materials (TRP)

Introduction

• This research program is aimed at evaluating different types of environment-induced degradation of candidate target materials for applications in transmutation of spent nuclear fuels (SNF).

• Transmutation refers to the elimination of long-lived actinides and fission products from SNF.

Objectives

• Evaluate susceptibility of candidate target materials to stress corrosion cracking (SCC) and localized corrosion (pitting and crevice) in neutral and acidic aqueous environments at ambient and elevated temperatures

• Determine the extent and morphology of cracking in tested materials as functions of experimental and environmental variables including pH, temperature, loading conditions and specimen geometry

• Develop mechanistic …

Density Of States Simulations Of Proteins, Nitin Rathore, Thomas A. Knotts Iv, Juan J. De Pablo

Faculty Publications

A modified version of a recently introduced algorithm that calculates density of states by performing a random walk in energy space has been proposed and implemented to study protein folding in a continuum. A united atom representation and the CHARMM19 [B. R. Brooks, R. E. Bruccoleri, B. D. Olafson, D. J. States, S. Swaminathan, and M. Karplus, J. Comput. Chem. 4, 187 (1983)] force field are employed for these simulations. This method permits estimation of the density of states of a protein via a random walk in the energy space, thereby allowing the system to escape from local free-energy minima …

Dynamics Of Adsorbed Poly(Methyl Acrylate) And Poly(Methyl Methacrylate) On Silica, Frank D. Blum, Wuu-Yung Lin, Crystal E. Porter

Chemistry Faculty Research & Creative Works

Deuterium NMR and modulated differential scanning calorimetry (MDSC) were used to probe the behavior of ultrathin adsorbed poly(methyl acrylate) (PMA). The spectra for the bulk methyl-labeled PMA-d3 were consistent with the motions of the polymer segments being spatially homogeneous. For the polymers adsorbed on silica, multicomponent line shapes were observed. The segmental mobility of the surface polymers increased with increased adsorbed amounts. In contrast to the behavior of the polymers in bulk, the adsorbed lower-molecular-mass PMA-d3 was less mobile than the adsorbed high-molecular-mass polymer. The presence of a polymer overlayer was sufficient to suppress the enhanced mobility of the more-mobile …

Analysis Of Anion Distributions In The Developing Strata Of A Constructed Wetland Used For Chlorinated Ethene Remediation, Joshua D. Kovacic

Theses and Dissertations

Perchloroethene (PCE), Trichloroethene (TCE) and their degradation products are among the most common organic groundwater contaminants in the United States. Constructed wetlands utilizing upward flow harbor reduction-oxidation conditions that have demonstrated the potential to promote both partial and total mineralization of PCE and TCE through the process of natural attenuation. Organic acid and inorganic anion concentrations are indicative of reduction-oxidation processes that drive chlorinated ethene degradation. These analytes were investigated to assess their development within three vertically stratified regions of a constructed wetland cell at Wright-Patterson Air Force Base fed by groundwater contaminated with PCE and TCE. Data collected during …

Environment-Induced Degradation And Crack-Growth Studies Of Candidate Target Materials, Ajit K. Roy, Brendan O'Toole

Transmutation Sciences Materials (TRP)

During the past two years (2001-2002) of this project, the primary effort was focused on evaluating the effect of hydrogen on the cracking behavior of candidate target materials namely, Alloys EP-823, HT-9 and 422 in aqueous environments of different pH values at ambient and elevated temperatures. More recently, emphasis is being placed to evaluate the cracking behavior of these materials in molten lead-bismuth eutectic (LBE) environment at much higher testing temperatures so as to compare the cracking susceptibility in environments containing molten metals and aqueous solutions, respectively. The most recent tests to evaluate the cracking susceptibility were primarily based on …

Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics: Quarterly Progress Report 12/1/02- 2/28/03, Samir Moujaes, Yitung Chen

Transmutation Sciences Materials (TRP)

The Lead-Bismuth eutectic (LBE) has been determined from previous experimental studies by the Russians and the European scientific community to be a potential material that can be used as a spallation target and coolant for the AAA proposed application.

Properly controlling the oxygen content in LBE can drastically reduce the LBE corrosion to structural steels. However, existing knowledge of material corrosion performance was obtained from point-wise testing with very limited density. The transport of oxygen and corrosion products, their interaction and variation of corrosion/precipitation along the flow are not well understood.

The first subtask of this project involves using a …

Magnetic Resonance Studies On Lithium Intercalation Into Carbons, Xiao-Rong Zhou, Zhen-Ming Du, Lin Zhuang, Jun-Tao Lu

Journal of Electrochemistry

The electron spin resonance(ESR) and 7Li-NMR magnetic resonance (7Li-NMR) studies on lithium intercalation into carbons were reviewed based on recently published papers, including those by the authors of this review. Two kinds of electronic spins were found in ESR studies. One corresponds to the charge carrier electrons and is called the Pauli spin. From the ESR intensity of Pauli spins, the curve of the density of electronic states can be deduced for the carbon material studied and, in turn, the contribution of the band model mechanism to the lithium intercalation can be calculated for the given carbon sample. The other …