This invention provides a CO equilibrium in a device for measuring the total concentration of oxy... more This invention provides a CO equilibrium in a device for measuring the total concentration of oxygen impurities in a fluid stream. To this end, the CO equilibrium is produced in an electrochemical measuring cell by the interaction of a carbon element in the cell with the chemically combined and uncombined oxygen in the fluid stream at an elevated temperature.
An electrochemical, solution-phase process deposits a controlled thickness, non-covalent layer of... more An electrochemical, solution-phase process deposits a controlled thickness, non-covalent layer of silica dielectric on carbon nanotubes.
Simple linear potentiodynamic cycling measurements have been made on abraded pure Al in borate, c... more Simple linear potentiodynamic cycling measurements have been made on abraded pure Al in borate, chromate, phosphate, sulfate and nitrate solutions. In borate and chromate solutions the currents continued to decrease with each subsequent cycle. In phosphate dissolution of the oxide takes place producing repetitive repeat curves. The current variations in borate and chromate were simulated using a high field conduction
A composite wire microelectrode for making electro-chemical measurements, and method of making sa... more A composite wire microelectrode for making electro-chemical measurements, and method of making same. The microelectrode includes an inner conductive sensing wire and an outer tube that is oxidized to form a dielectric, self-healing oxide layer around the sensing wire.
High brightness synchrotron radiation incident at glancing angles has been used to study inhibiti... more High brightness synchrotron radiation incident at glancing angles has been used to study inhibiting species present in low concentrations in oxide films on aluminum. Glancing incident angle fluorescence measurements give surface-sensitive information on the valence state of elements from the shape of the x ray absorption edge. Angle-resolved measurements show the depth distribution of the species present.
ABSTRACT in situ glancing-angle x-ray reflectivity experiments were performed on electrochemical ... more ABSTRACT in situ glancing-angle x-ray reflectivity experiments were performed on electrochemical reduction products formed in a dilute paramolybdate solution on a platinum electrode. These data were compared with x-ray photoelectron spectra which showed formation of simple molybdate, pentavalent and tetravalent species at increasingly negative potentials. X-ray absorption data demonstrated changes in edge position, pre-edge structure and edge height corresponding to reduction and subsequent growth of the reduction product film at a number of the potentials examined with XPS.
Research on advanced electrolytic hydrogen production consisted of two areas. One was the develop... more Research on advanced electrolytic hydrogen production consisted of two areas. One was the development of an electrochemical method for investigation of the solid polymer electrolyte (SPE) electrocatalyst interface, the other was the development of stable photoanodes for photodecomposition of water by coating low barrier n type semiconductor with a thin film of n type TiO2. By using various types of contact electrodes on SPE membranes, it was possible to use modern electrochemical techniques to investigate the SPE electrocatalyst interface under conditions simulating electrolyzer operation. Low barrier heterojunctions of thin films of n type TiO2 on n type Fe2O3 were successfully demonstrated.
A new method has been developed for the study of bare surface electrochemistry at shorter times a... more A new method has been developed for the study of bare surface electrochemistry at shorter times and higher current densities than those conventionally achieved. This technique involves in situ fracture of a sputtered metal film between two glass slides to create a band microelectrode. This has the advantage over electrodes of conventional size of an increase in the rate of mass transport to and from the surface and reduction in the ohmic (IR) drop. The bare microelectrode method has been used to study the repassivation kinetics of sputtered niobium films.
ABSTRACT X-ray absorption spectroscopy is a powerful technique for determination of valency and c... more ABSTRACT X-ray absorption spectroscopy is a powerful technique for determination of valency and coordination. Measurements can be made in air or in situ under electrochemical control. The technique will be described and its application to the analysis of passive oxide films, corrosion products, and inhibitors will be reviewed.
An a.c. electrochemical technique that meets the basic requirements for an in situ localized corr... more An a.c. electrochemical technique that meets the basic requirements for an in situ localized corrosion monitor within the secondary coolant of PWR steam generators has been investigated. The technique uses two electrodes to measure the electrochemical impedance of a surface in an occluded region with high heat flux. This impedance is related to the kinetics of corrosion and marked decreases indicate the onset of a high corrosion rate.
This invention provides a CO equilibrium in a device for measuring the total concentration of oxy... more This invention provides a CO equilibrium in a device for measuring the total concentration of oxygen impurities in a fluid stream. To this end, the CO equilibrium is produced in an electrochemical measuring cell by the interaction of a carbon element in the cell with the chemically combined and uncombined oxygen in the fluid stream at an elevated temperature.
An electrochemical, solution-phase process deposits a controlled thickness, non-covalent layer of... more An electrochemical, solution-phase process deposits a controlled thickness, non-covalent layer of silica dielectric on carbon nanotubes.
Simple linear potentiodynamic cycling measurements have been made on abraded pure Al in borate, c... more Simple linear potentiodynamic cycling measurements have been made on abraded pure Al in borate, chromate, phosphate, sulfate and nitrate solutions. In borate and chromate solutions the currents continued to decrease with each subsequent cycle. In phosphate dissolution of the oxide takes place producing repetitive repeat curves. The current variations in borate and chromate were simulated using a high field conduction
A composite wire microelectrode for making electro-chemical measurements, and method of making sa... more A composite wire microelectrode for making electro-chemical measurements, and method of making same. The microelectrode includes an inner conductive sensing wire and an outer tube that is oxidized to form a dielectric, self-healing oxide layer around the sensing wire.
High brightness synchrotron radiation incident at glancing angles has been used to study inhibiti... more High brightness synchrotron radiation incident at glancing angles has been used to study inhibiting species present in low concentrations in oxide films on aluminum. Glancing incident angle fluorescence measurements give surface-sensitive information on the valence state of elements from the shape of the x ray absorption edge. Angle-resolved measurements show the depth distribution of the species present.
ABSTRACT in situ glancing-angle x-ray reflectivity experiments were performed on electrochemical ... more ABSTRACT in situ glancing-angle x-ray reflectivity experiments were performed on electrochemical reduction products formed in a dilute paramolybdate solution on a platinum electrode. These data were compared with x-ray photoelectron spectra which showed formation of simple molybdate, pentavalent and tetravalent species at increasingly negative potentials. X-ray absorption data demonstrated changes in edge position, pre-edge structure and edge height corresponding to reduction and subsequent growth of the reduction product film at a number of the potentials examined with XPS.
Research on advanced electrolytic hydrogen production consisted of two areas. One was the develop... more Research on advanced electrolytic hydrogen production consisted of two areas. One was the development of an electrochemical method for investigation of the solid polymer electrolyte (SPE) electrocatalyst interface, the other was the development of stable photoanodes for photodecomposition of water by coating low barrier n type semiconductor with a thin film of n type TiO2. By using various types of contact electrodes on SPE membranes, it was possible to use modern electrochemical techniques to investigate the SPE electrocatalyst interface under conditions simulating electrolyzer operation. Low barrier heterojunctions of thin films of n type TiO2 on n type Fe2O3 were successfully demonstrated.
A new method has been developed for the study of bare surface electrochemistry at shorter times a... more A new method has been developed for the study of bare surface electrochemistry at shorter times and higher current densities than those conventionally achieved. This technique involves in situ fracture of a sputtered metal film between two glass slides to create a band microelectrode. This has the advantage over electrodes of conventional size of an increase in the rate of mass transport to and from the surface and reduction in the ohmic (IR) drop. The bare microelectrode method has been used to study the repassivation kinetics of sputtered niobium films.
ABSTRACT X-ray absorption spectroscopy is a powerful technique for determination of valency and c... more ABSTRACT X-ray absorption spectroscopy is a powerful technique for determination of valency and coordination. Measurements can be made in air or in situ under electrochemical control. The technique will be described and its application to the analysis of passive oxide films, corrosion products, and inhibitors will be reviewed.
An a.c. electrochemical technique that meets the basic requirements for an in situ localized corr... more An a.c. electrochemical technique that meets the basic requirements for an in situ localized corrosion monitor within the secondary coolant of PWR steam generators has been investigated. The technique uses two electrodes to measure the electrochemical impedance of a surface in an occluded region with high heat flux. This impedance is related to the kinetics of corrosion and marked decreases indicate the onset of a high corrosion rate.
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Papers by Hugh Isaacs