The Electrochemistry of Corrosion

“…Polarography (48)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59)(60) Methods have been developed for the measurement of minute quantities of dissolved metal salts in solution; or determination of the change in concentration of a corrosive constituent as it reacts with the metal and is removed from solution. For example, the concentration of the aluminum, zinc, and magnesium may be determined in a given electrolyte after immersion of the specimens for a given time.…”

Section: A Direct and Indirect Methodsmentioning

confidence: 99%

Research on Treated Magnesium Surfaces

Rohowetz¹

1955

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“…Any operation that removes a portion of this film enhances the apparent "solution potential" of the metal (19). The results of Brown and Mears (20) show that the potential of A1 becomes more anodic as the film is progressively scratched. A potential difference of 0.32 v was noted between the potentials of an unseratehed coupon and one scratched by a standard procedure.…”

Section: Potentials In Columbia River Watermentioning

confidence: 97%

Thermogalvanic Potentials and Currents at Aluminum Surfaces in Industrial Water

Pitzer¹

1957

J. Electrochem. Soc.

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normal until it began to fluctuate at @. Although this fluctuation was found on two of the four cells in this cycle, it is not characteristic of a normal charge. Lacking any other information, this erratic behavior might be confused with a bad electrical connection or breakdown of measuring component. A similar fluctuation ~ppears at Q on cell 2, but, from the additional data taken, it is obvious that the fluctuations in the cell voltage are due to fluctuations in the negative plate potential @, and are also reflected in the H concentration at Q. The volmne of the gas meter per revolution was large enough to obscure a similar fluctuation appearing in the gassing rate at @, but it was undoubtedly there.Gas measurements @ also indicate that gas evolution began early in the charge for cell 2. This suggests that the cell was either not deeply discharged or that it was not taking a charge. Calculations from the gas record @ indicate that the net charge put into the positive plate of cell 2 was, however, about equal to the rated capacity of the cell. This would be the maximum, since positive plate capacity normally limits the cell capacity. In sharp contrast, the negative plate appears to have charged quite efficiently with only a limited amount of H having been evolved during the charge | When the charge was stopped, over twice the rated capacity of the cell appears to have been put into the negative plate; yet the lack of H evolution showed it was far from being fully charged. Furthermore, the negative plate potential began to drop near the end of the following discharge @ in spite of the long charge. All this suggests that the self-discharge rate of the Cd plate was high under these conditions of stand and that there was a high ratio of negative plate to positive plate capacity in this battery.More recent work on similar cells indicates that the apparent amount of charge taken by the Cd plate was not necessarily related to the true capacity. Gas measurements during stand show that the gassieg rate of the Ni-Cd battery dropped off rapidly during the first few hours of stand. This lack of gas evolution does not mean that selfdischarge had stopped, however, for residual discharges following stands indicate appreciably more capacity loss than could be accounted for by the evolved gas. While the cell characteristics were being observed on a 24 hr/day basis, the cell actually began to absorb oxygen from the atmosphere; this oxygen in turn oxidized the Cd plate. Thus, it is sometimes possible to pick up and interpret unexpected characteristics from the detailed measurements on a 24 hr/day basis. A permanent record is also available for future evaluation in the light of later developments.ABSTRACT Potentials and galvanic currents at 2S A1 surfaces in Columbia River water were studied between room temperature and 100~ The A1 potential changed by approximately 0.6 v over this interval, becoming more anodic with increase in temperature. Similar but somewhat smaller changes in potential were noted in buffer solutions.]~y coupli...

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The Electrochemistry of Corrosion

Cited by 47 publications

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CORROSION SCIENCE AND ITS APPLICATION TO SOLAR THERMAL ENERGY MATERIAL PROBLEMS11This work is supported by the Division of Solar Technology, U.S. Department of Energy (DOE), under contract EG-77-C-01-4042.

CORROSION SCIENCE AND ITS APPLICATION TO SOLAR THERMAL ENERGY MATERIAL PROBLEMS11This work is supported by the Division of Solar Technology, U.S. Department of Energy (DOE), under contract EG-77-C-01-4042.

Research on Treated Magnesium Surfaces

Thermogalvanic Potentials and Currents at Aluminum Surfaces in Industrial Water

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