The Significance of the Flade Potential

Pryor, M. J.

doi:10.1149/1.2427437

Cited by 38 publications

(30 citation statements)

References 17 publications

(54 reference statements)

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“…[7]. Accordingly the passivation potential observed in neutral borate solutions can be interpreted as corresponding to the equilibrium potential for the reaction between ~,-Fe203 and Fe + + ion in solution.…”

Section: Significance Of the Passivation Potentialmentioning

confidence: 99%

The Anodic Oxidation of Iron in a Neutral Solution

Nagayama

Cohen²

1963

J. Electrochem. Soc.

197

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The anodic polarization curve, the static passive potential, and the behavior of the decay of the polarized passive potential of iron were examined in neutral boric acid/borate solutions with and without Fe++ ion addition. It was found that the passivation potential is a function of the [Fe++] and pH and corresponds to the equilibrium potential of the reaction of γ‐Fe2O3+6H++2e⇄2Fe+++3H2O . The polarized passive potential in the steady state is related to a pseudoequilibrium potential that corresponds to a higher defect concentration in the oxide surface and to a lower [Fe++] at the oxide/solution interface. The potential gradient across the film appears to be very small. The decay of the polarized passive potential on open circuit is explained as due mainly to the change in the defect‐concentration and consequently of the film composition at the oxide/solution interface either by the outward migration of iron through the film or by the reaction with Fe++ ion in solution when the latter had been added or supplied by a small amount of self‐corrosion.

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Section: Significance Of the Passivation Potentialmentioning

confidence: 99%

The Anodic Oxidation of Iron in a Neutral Solution

Nagayama

Cohen²

1963

J. Electrochem. Soc.

197

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“…The authors proposed the existence of a higher valence state of Fe in the outer region of the passive film to account for this observation. Pryor (28) proposed earlier the existence of a gradation in defect concentration throughout a single-phase y-Fe 2 0 3 passive film with the passive oxide near the oxide-metal interface containing excess cations (metal excess, n type) and with the passive oxide near the oxide-solution interface containing excess oxygen ions (metal deficient, p type). Electrical neutrality is provided by the existence of the appropriate number of negative holes near the oxide-metal interface and positive holes near the oxide-solution interface.…”

Section: Mechanism Of Passivationmentioning

confidence: 99%

“…Dielectric measurements and polarization studies (74) show that electrical neutrality in the oxide is restored by the reaction A1(Lr + 30fL) + 3CI(s) + 3H(~) = 3Clii) + AIM + 30H(s) (28) where the subscript (L) refers to the lattice and (S) to the solution. Accordingly, the three-electron deficiency resulting from three CI--0 2 -exchanges is compensated by one aluminum ion passing into solution.…”

Section: Pitting In the Active Potential Rangementioning

confidence: 99%

Metal-Liquid Reactions: Corrosion

Pryor

Staehle

1976

Treatise on Solid State Chemistry

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“…On the basis of the values of E pp (1,220 mV), some investigators have reported that the protective layer probably corresponds to a nonstoichometric higher oxide of iron. [8][9] However, it was difficult to ascertain the nature and composition of the film on the basis of results of the present investigation (E pp = 420 mV to 750 mV).…”

Section: Corrosion Science Sectionmentioning

confidence: 73%

Corrosion Behavior of Mild Steel in Acetic Acid Solutions

Singh¹,

Gupta²

2000

CORROSION

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The corrosion behavior of mild steel in acetic acid (CH 3 COOH) solutions was studied by weight loss and potentiostatic polarization techniques. The variation in corrosion rate of mild steel with concentrations of CH 3 COOH, evaluated by weight loss and electrochemical techniques, showed marked resemblance. From both techniques, the maximum corrosion rate was observed for 20% CH 3 COOH solution at all three experimental temperatures (25, 35, and 45°C). Anodic polarization curves showed active-passive behavior at each concentration, except at 80% CH 3 COOH. Critical current density (i c ), passive current density (i n ), primary passivation potential (E pp ), and potential for passivity (E p ) had their highest values in 20% CH 3 COOH solution. With an increase in temperature, while the anodic polarization curves shifted toward higher current density region at each concentration, the passive region became progressively less distinguishable. With the addition of sodium acetate (NaCOOCH 3 ) as a supporting electrolyte, the passive range was enlarged substantially. However, the transpassive region commenced at more or less the same potential. Cathodic polarization curves were almost identical irrespective of the concentration of CH 3 COOH or temperature.

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The Significance of the Flade Potential

Cited by 38 publications

References 17 publications

The Anodic Oxidation of Iron in a Neutral Solution

The Anodic Oxidation of Iron in a Neutral Solution

Metal-Liquid Reactions: Corrosion

Corrosion Behavior of Mild Steel in Acetic Acid Solutions

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