W. Smyrl - Academia.edu (original) (raw)
Papers by W. Smyrl
Aluminum was used to investigate the mass change associated with different Volatile Corrosion Inh... more Aluminum was used to investigate the mass change associated with different Volatile Corrosion Inhibitors (VCIs) by using the Quartz Crystal Microbalance (QCM) and aluminum 2024 was characterized using a Scanning Electron Microscope (SEM). An atmosphere containing H{sub 2}S, SO{sub 2}, H{sub 2}SO{sub 4}, NH{sub 4}Cl and KBr at a Critical Relative Humidity (CRH) of 80 and up to 100% and where temperatures were between 5 and 50 C was used to corrode the aluminum 2024. The SEM images of the uninhibited 2024 samples revealed a highly corroded surface, whereas the inhibited samples showed less attack after exposure to the aggressive environments. Analysis of the inclusions within the aluminum matrix showed that the addition of certain VCIs prevented attack of both the matrix and the inclusion particles (containing Mg, Mn, Fe and Cu), whereas the non-inhibited sample showed partial corrosion of the particles. The QCM data supports the data and the images taken on the SEM by showing a distinctive mass change from the adsorption of the inhibitor in the gas phase.
Electrochimica Acta, 1993
Photoelectrochemical measurements on thin metal-oxide films are discussed. It is shown that for v... more Photoelectrochemical measurements on thin metal-oxide films are discussed. It is shown that for very thin films, multiple internal reflection effects cause the photocurrent to be. a strong function of lilm thickness. The discussion also includes metal-oxide/electrolyte interface dominated photocurrent and metal-oxide/metal interface dominated internal photoemission processes.
New Trends in Electrochemical Technology, 2002
Journal of The Electrochemical Society, 1990
Un modele analytique permettant l'analyse de l'impedance d'une electrode a disque tou... more Un modele analytique permettant l'analyse de l'impedance d'une electrode a disque tournant dans un large domaine de frequences est etudie lors d'une diffusion convective
Electrochimica Acta, 1998
The eect of thiourea on copper was investigated in solutions of sulfuric acid. Weak interaction o... more The eect of thiourea on copper was investigated in solutions of sulfuric acid. Weak interaction occurs at low concentrations of thiourea. At high concentrations of thiourea (>1 mM), strong eects were observed. Thiourea forms complexes with cuprous ions in solution which shift the open circuit potential of the copper electrode in a negative direction and causes copper to dissolve to cuprous species even in sulfate media. At more positive potentials, thiourea reacts with cupric ions and forms a complex. At a sucient concentration of the cupric± thiourea complex, a sulfate complex ®lm forms. The ®lm can be formed reversibly upon cycling the copper electrode potential.
AIChE Journal, 1988
A heterogeneous electrode surface has been modeled using a regular distribution of circular anode... more A heterogeneous electrode surface has been modeled using a regular distribution of circular anodes in a surrounding coplanar cathodic matrix. In the absence of mass transport effects, galvanic currents and potentials have been calculated using finite-element analysis, with nonlinear electrode kinetics. For a fixed ratio of anodic to cathodic areas on a heterogeneous surface, calculated galvanic currents increase linearly with the active perimeter between cathodic and anodic regions. Furthermore, the current is independent of the shapes and distributions of anodic regions in a surrounding cathodic plane provided that the ratio of overall anodic area to active perimeter is conserved. Thus, due to its longer active perimeter, a surface represented by a large number of tiny anodic islands dispersed in a cathodic sea will exhibit much greater galvanic currents than an equivalent surface represented by a small number of large anodic continents.
Chemistry of Materials, 1995
Vanadium pentoxide xerogel films spin-coated on nickeYsilicon substrates have shown high electroc... more Vanadium pentoxide xerogel films spin-coated on nickeYsilicon substrates have shown high electrochemical performance. In fact, more than 3 equiv of lithium Vz05 unit can be reversibly inserted between 3.5 and 1.6 V in aprotic electrolytes. The high insertion capacity coupled with the inexpensive and well-known preparation procedure make the material interesting for thin-film lithium battery and electrochromic device applications. In the present paper we report the characterization of such thin films based on X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), quartz crystal microbalance, optical, and electronic conductivity measurements. The spin-coated films are highly amorphous, with a small amount of ribbon stacking that is randomly oriented. The disorder is caused by the joint effect of high shear and rapid drying during spin coating.
Journal of The Electrochemical Society, 1989
The present contribution provides a systematic treatment of the proximity effect of the electrode... more The present contribution provides a systematic treatment of the proximity effect of the electrodes on the current and potential distributions at a hole in an electroactive resistive overlayer of a «sandwich» structure. General mathematical expressions for the electrode kinetics are employed
The breakdown of native and anodically-grown oxide films on Ti electrodes is investigated by scan... more The breakdown of native and anodically-grown oxide films on Ti electrodes is investigated by scanning electrochemical microscopy (SECM), video microscopy, transmission electron microscopy and voltammetry. SECM is used to demonstrate that the oxidation of Br- on Ti occurs at microscopic surface sites (10 - 50 micrometer diameter, 30 sites/sq cm) that are randomly positioned across the oxide surface. After determining
A conductive composite material useful as an electrode, comprises a conductor and an organic poly... more A conductive composite material useful as an electrode, comprises a conductor and an organic polymer which is reversibly electrochemically dopable to change its electrical conductivity. Said polymer continuously surrounds the conductor in intimate electrical contact therewith and is prepared by electrochemical growth on said conductor or by reaction of its corresponding monomer(s) on said conductor which has been pre-impregnated or pre-coated with an activator for said polymerization. Amount of the conductor is sufficient to render the resultant composite electrically conductive even when the polymer is in an undoped insulating state.
Journal of the Korean Electrochemical Society, 2004
Journal of The Electrochemical Society, 2000
... M. Büchler, J. Kerimo, F. Guillaume, WH Smyrl. Abstract. The localized corrosion behavior of ... more ... M. Büchler, J. Kerimo, F. Guillaume, WH Smyrl. Abstract. The localized corrosion behavior of Al 2024 was investigated by using a fluorescent dye in combination with conventional fluorescence microscopy and near-field scanning optical microscopy. ...
Journal of The Electrochemical Society, 1997
Localized attack on aluminum alloy 2024 in the presence of 0.1 M KCl was investigated using fluor... more Localized attack on aluminum alloy 2024 in the presence of 0.1 M KCl was investigated using fluorescence microscopy. The study was conducted by high resolution confocal laser scanning microscopy in an in situ fluorescence mode. Fluorescein dye was used to indicate pH changes and surface chemistry over and around the active sites. Localized attack on Al was enhanced by the presence of inclusions and second-phase particles of different types. It was found that the fluorescence signal was confined to the surface due to the entrapment of fluorescein in the corrosion products formed on or around the inclusions.
Journal of The Electrochemical Society, 1989
Although lithium anodes offer many attractive features such as high energy density and high negat... more Although lithium anodes offer many attractive features such as high energy density and high negative electrode potentials, the advantages may be overshadowed by the disadvantages. The use of sodium anodes may be an attractive alternative therefore that is explored in the present research. Apart from work on the Na/S battery, the investigation of sodium secondary battery systems has been slow because of the stability problems experienced by the sodium anodes in most organic electrolytes. In this paper, the behavior of the cell Na/PEO/sub 8/.NaCF/sub 3/SO/sub 3//V/sub 6/O/sub 13/, operating at 95{sup 0}C is described.
Advanced Materials, 2006
ABSTRACT
ECS Transactions, 2014
The research reported here will focus on a miniature battery system that is inactive as assembled... more The research reported here will focus on a miniature battery system that is inactive as assembled (“off”). It is activated when a damaging fluid flows into the inter-electrode separator (“on”). In the “on” state, it powers a wireless sensor that transmits a signal to the base station monitor to announce that corrosion conditions have been created at the location of the battery – sensor. Further, the battery-sensor powered the measurement of the time-to-failure (TTF) of a corroding specimen that was initiated when the fluid arrived (on), and ended when the specimen failed (off). The on/off action is a “large” signal that is insensitive to electrical noise from the ambient surroundings.
Journal of the Electrochemical Society, 1989
The electrochemistry and photoelectrochemistry of nominal one monolayer coverages of RuO2 deposit... more The electrochemistry and photoelectrochemistry of nominal one monolayer coverages of RuO2 deposited by thermal
decomposition of RuC13 on anodically grown TiO2 films are examined. The anodic TiO~ films, characterized by electron
diffraction before and after thermal treatment, were found to be polycrystalline rutile. Anodic films grown by potential
step polarization did not allow penetration of RuO2 into the film. Conversely, TiO2 films grown at potential ramping rates
of 0.1 mV/s had a structure which allowed RuO2 to penetrate into the film along TiO2 grain boundaries. Surface films of
RuO2 exhibited an electrocatalytic effect but also strongly reduced the photocurrent response. RuO2 additions to the films
which did penetrate the oxide acted as nonelectrocatalytically active species within the TiO2 layer and had little effect on
the photocurrent response of the oxide film. A model of RuO2 distribution at the surface and along the grain boundaries of
TiO2 crystallites is considered.
Single crystal graphite has been used as a prototype of the carbon electrode to study the lithium... more Single crystal graphite has been used as a prototype of the carbon electrode to study the lithium intercalation process and the interaction between a carbon electrode and an electrolyte in the lithium rechargeable battery. Scanning tunneling microscopy and transmission electron microscopy have been used to examine the microstructural changes of the same region of the electrode surface after electrochemical treatments down to an atomic level. This gives direct evidence of solvent cointercalation, graphite exfoliation, and surface film formation during the intercalation process.
Journal of Industrial and Engineering Chemistry, 1995
Aluminum was used to investigate the mass change associated with different Volatile Corrosion Inh... more Aluminum was used to investigate the mass change associated with different Volatile Corrosion Inhibitors (VCIs) by using the Quartz Crystal Microbalance (QCM) and aluminum 2024 was characterized using a Scanning Electron Microscope (SEM). An atmosphere containing H{sub 2}S, SO{sub 2}, H{sub 2}SO{sub 4}, NH{sub 4}Cl and KBr at a Critical Relative Humidity (CRH) of 80 and up to 100% and where temperatures were between 5 and 50 C was used to corrode the aluminum 2024. The SEM images of the uninhibited 2024 samples revealed a highly corroded surface, whereas the inhibited samples showed less attack after exposure to the aggressive environments. Analysis of the inclusions within the aluminum matrix showed that the addition of certain VCIs prevented attack of both the matrix and the inclusion particles (containing Mg, Mn, Fe and Cu), whereas the non-inhibited sample showed partial corrosion of the particles. The QCM data supports the data and the images taken on the SEM by showing a distinctive mass change from the adsorption of the inhibitor in the gas phase.
Electrochimica Acta, 1993
Photoelectrochemical measurements on thin metal-oxide films are discussed. It is shown that for v... more Photoelectrochemical measurements on thin metal-oxide films are discussed. It is shown that for very thin films, multiple internal reflection effects cause the photocurrent to be. a strong function of lilm thickness. The discussion also includes metal-oxide/electrolyte interface dominated photocurrent and metal-oxide/metal interface dominated internal photoemission processes.
New Trends in Electrochemical Technology, 2002
Journal of The Electrochemical Society, 1990
Un modele analytique permettant l'analyse de l'impedance d'une electrode a disque tou... more Un modele analytique permettant l'analyse de l'impedance d'une electrode a disque tournant dans un large domaine de frequences est etudie lors d'une diffusion convective
Electrochimica Acta, 1998
The eect of thiourea on copper was investigated in solutions of sulfuric acid. Weak interaction o... more The eect of thiourea on copper was investigated in solutions of sulfuric acid. Weak interaction occurs at low concentrations of thiourea. At high concentrations of thiourea (>1 mM), strong eects were observed. Thiourea forms complexes with cuprous ions in solution which shift the open circuit potential of the copper electrode in a negative direction and causes copper to dissolve to cuprous species even in sulfate media. At more positive potentials, thiourea reacts with cupric ions and forms a complex. At a sucient concentration of the cupric± thiourea complex, a sulfate complex ®lm forms. The ®lm can be formed reversibly upon cycling the copper electrode potential.
AIChE Journal, 1988
A heterogeneous electrode surface has been modeled using a regular distribution of circular anode... more A heterogeneous electrode surface has been modeled using a regular distribution of circular anodes in a surrounding coplanar cathodic matrix. In the absence of mass transport effects, galvanic currents and potentials have been calculated using finite-element analysis, with nonlinear electrode kinetics. For a fixed ratio of anodic to cathodic areas on a heterogeneous surface, calculated galvanic currents increase linearly with the active perimeter between cathodic and anodic regions. Furthermore, the current is independent of the shapes and distributions of anodic regions in a surrounding cathodic plane provided that the ratio of overall anodic area to active perimeter is conserved. Thus, due to its longer active perimeter, a surface represented by a large number of tiny anodic islands dispersed in a cathodic sea will exhibit much greater galvanic currents than an equivalent surface represented by a small number of large anodic continents.
Chemistry of Materials, 1995
Vanadium pentoxide xerogel films spin-coated on nickeYsilicon substrates have shown high electroc... more Vanadium pentoxide xerogel films spin-coated on nickeYsilicon substrates have shown high electrochemical performance. In fact, more than 3 equiv of lithium Vz05 unit can be reversibly inserted between 3.5 and 1.6 V in aprotic electrolytes. The high insertion capacity coupled with the inexpensive and well-known preparation procedure make the material interesting for thin-film lithium battery and electrochromic device applications. In the present paper we report the characterization of such thin films based on X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), quartz crystal microbalance, optical, and electronic conductivity measurements. The spin-coated films are highly amorphous, with a small amount of ribbon stacking that is randomly oriented. The disorder is caused by the joint effect of high shear and rapid drying during spin coating.
Journal of The Electrochemical Society, 1989
The present contribution provides a systematic treatment of the proximity effect of the electrode... more The present contribution provides a systematic treatment of the proximity effect of the electrodes on the current and potential distributions at a hole in an electroactive resistive overlayer of a «sandwich» structure. General mathematical expressions for the electrode kinetics are employed
The breakdown of native and anodically-grown oxide films on Ti electrodes is investigated by scan... more The breakdown of native and anodically-grown oxide films on Ti electrodes is investigated by scanning electrochemical microscopy (SECM), video microscopy, transmission electron microscopy and voltammetry. SECM is used to demonstrate that the oxidation of Br- on Ti occurs at microscopic surface sites (10 - 50 micrometer diameter, 30 sites/sq cm) that are randomly positioned across the oxide surface. After determining
A conductive composite material useful as an electrode, comprises a conductor and an organic poly... more A conductive composite material useful as an electrode, comprises a conductor and an organic polymer which is reversibly electrochemically dopable to change its electrical conductivity. Said polymer continuously surrounds the conductor in intimate electrical contact therewith and is prepared by electrochemical growth on said conductor or by reaction of its corresponding monomer(s) on said conductor which has been pre-impregnated or pre-coated with an activator for said polymerization. Amount of the conductor is sufficient to render the resultant composite electrically conductive even when the polymer is in an undoped insulating state.
Journal of the Korean Electrochemical Society, 2004
Journal of The Electrochemical Society, 2000
... M. Büchler, J. Kerimo, F. Guillaume, WH Smyrl. Abstract. The localized corrosion behavior of ... more ... M. Büchler, J. Kerimo, F. Guillaume, WH Smyrl. Abstract. The localized corrosion behavior of Al 2024 was investigated by using a fluorescent dye in combination with conventional fluorescence microscopy and near-field scanning optical microscopy. ...
Journal of The Electrochemical Society, 1997
Localized attack on aluminum alloy 2024 in the presence of 0.1 M KCl was investigated using fluor... more Localized attack on aluminum alloy 2024 in the presence of 0.1 M KCl was investigated using fluorescence microscopy. The study was conducted by high resolution confocal laser scanning microscopy in an in situ fluorescence mode. Fluorescein dye was used to indicate pH changes and surface chemistry over and around the active sites. Localized attack on Al was enhanced by the presence of inclusions and second-phase particles of different types. It was found that the fluorescence signal was confined to the surface due to the entrapment of fluorescein in the corrosion products formed on or around the inclusions.
Journal of The Electrochemical Society, 1989
Although lithium anodes offer many attractive features such as high energy density and high negat... more Although lithium anodes offer many attractive features such as high energy density and high negative electrode potentials, the advantages may be overshadowed by the disadvantages. The use of sodium anodes may be an attractive alternative therefore that is explored in the present research. Apart from work on the Na/S battery, the investigation of sodium secondary battery systems has been slow because of the stability problems experienced by the sodium anodes in most organic electrolytes. In this paper, the behavior of the cell Na/PEO/sub 8/.NaCF/sub 3/SO/sub 3//V/sub 6/O/sub 13/, operating at 95{sup 0}C is described.
Advanced Materials, 2006
ABSTRACT
ECS Transactions, 2014
The research reported here will focus on a miniature battery system that is inactive as assembled... more The research reported here will focus on a miniature battery system that is inactive as assembled (“off”). It is activated when a damaging fluid flows into the inter-electrode separator (“on”). In the “on” state, it powers a wireless sensor that transmits a signal to the base station monitor to announce that corrosion conditions have been created at the location of the battery – sensor. Further, the battery-sensor powered the measurement of the time-to-failure (TTF) of a corroding specimen that was initiated when the fluid arrived (on), and ended when the specimen failed (off). The on/off action is a “large” signal that is insensitive to electrical noise from the ambient surroundings.
Journal of the Electrochemical Society, 1989
The electrochemistry and photoelectrochemistry of nominal one monolayer coverages of RuO2 deposit... more The electrochemistry and photoelectrochemistry of nominal one monolayer coverages of RuO2 deposited by thermal
decomposition of RuC13 on anodically grown TiO2 films are examined. The anodic TiO~ films, characterized by electron
diffraction before and after thermal treatment, were found to be polycrystalline rutile. Anodic films grown by potential
step polarization did not allow penetration of RuO2 into the film. Conversely, TiO2 films grown at potential ramping rates
of 0.1 mV/s had a structure which allowed RuO2 to penetrate into the film along TiO2 grain boundaries. Surface films of
RuO2 exhibited an electrocatalytic effect but also strongly reduced the photocurrent response. RuO2 additions to the films
which did penetrate the oxide acted as nonelectrocatalytically active species within the TiO2 layer and had little effect on
the photocurrent response of the oxide film. A model of RuO2 distribution at the surface and along the grain boundaries of
TiO2 crystallites is considered.
Single crystal graphite has been used as a prototype of the carbon electrode to study the lithium... more Single crystal graphite has been used as a prototype of the carbon electrode to study the lithium intercalation process and the interaction between a carbon electrode and an electrolyte in the lithium rechargeable battery. Scanning tunneling microscopy and transmission electron microscopy have been used to examine the microstructural changes of the same region of the electrode surface after electrochemical treatments down to an atomic level. This gives direct evidence of solvent cointercalation, graphite exfoliation, and surface film formation during the intercalation process.
Journal of Industrial and Engineering Chemistry, 1995