A d‐c current interrupter method has been developed for oscilloscopic studies of time‐potential changes at an electrode surface during short interruption intervals. A variable length square pulse with a very short rise time and with a duty factor of approximately one per cent was used to interrupt the current flow in a cell. Studies were conducted using interruption times from one microsecond to 120 microseconds.This interrupter technique permitted correction for the resistance error in closed circuit potential measurements. Polarization decay and build‐up could be followed as the current was cut off and turned on, and the potential changes and double layer capacity effects occurring at an electrode surface during interruption could be measured. These phenomena have been discussed in terms of an equivalent electrical circuit. An initial study of polarization phenomena on the zinc anode‐steel cathode system in a synthetic sea water electrolyte was carried out using this interrupter method.
An innovative treatment of III-V surface is evidenced in liquid ammonia (NH 3 liq).This treatment is performed by a controlled anodic electrochemical process at the interface. [1] This control provides a novel and reproducible passivation of the InP surface. [1] The surface coating prevents the formation of oxides for over a year.[1] The low anodic charge (≈1 mC.cm −2 range) spent for the process concurrently involves a weak electrochemical dissolution of InP surface and ammonia oxidation which trigger the passivation process.[1] Studies using either cyclic voltammetry or galvanostatic treatment followed by XPS measurements show that the surface is successfully passivated by an ultrathin film associating phosphorus and nitrogen atoms in a quasi-monolayer structure. Reproducible XPS data indicate that the ratio between nitrogen and phosphorus atoms in the film is close to two. High resolution N 1s spectra reveal a double structure of the peaks, indicating that two chemical environments must be considered to describe the nitrogen atoms neighboring in this capping film. Information about the spatial film organization are investigated by angular-resolved XPS depth profiles analysis. Experiments are performed with a Thermo Fisher Scientific Theta Probe XPS spectrometer which exhibits an innovative ARXPS acquisition mode. The evolution of the respective contributions of P and N or In signals, perpendicularly to the surface, permit to propose a paving of the surface with a polyphospazene like film. Copyright
DISCUSSION SECTION 259 exceed 0.10 per cent (or 2-2.4.10 -6 g/cm 2) if adherent plating of acceptable commercial quality is to be guaranteed. ~. L. HOLTa9: The authors mention that one of the limitations of the technique described is the small anlount of surface that can be used due to the area of the counter window. Would it not be possible to use a larger surface area and.cut it into sections small enough for the counter, thus also solving the problem of counting over the whole larger surface area? J. C. HARRIS, R. E. KAMP, AND W. H. YANKO: Perhaps it might be possible to cut the soiled or washed specimens for examination, but an even better procedure would be to use the same or a slightly larger specimen which could be introduced as a complete sample into a counting chamber. Further sensitivity of method could be attained through the use of a proportional counter.J. J. BIKERMAN40: It should be possible to utilize the excellent method worked out by Harris, Kamp, and Yanko also for estimating the surface roughness of a specimen. Spread a standard amount of the standard soiling composition on the specinlen surface. Rub this with some bibulous material, again in a standardized manner. The amount of soil remaining on the surface certainly will, as a rule, be greater the rougher the surface.J. C. HARRIS, R. E. KAMP, AND W. H. YANKO: Dr. Bikerman's suggestion that the tracer method be used for estimating surface roughness is an interesting one and might prove of much value in such work.
Final Report on theFIowsheet Model for the Electrochemical Treatment of. Liquid Radioactive Wastes cu) Attached is the final report pspared by the University of South Carolha under contract #AAoo9OOT, Task #112, developing engineexkg models for the electrochemical destruction of nitrates and organic comgounds in liquidradioactive wastes.
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