A Point Defect Model for Anodic Passive Films: I . Film Growth Kinetics

Abstract

A model based on the movement of point defects in an electrostatic field is proposed to interpret the growth behavior of a passive film on a metal surface. This model results in a logarithmic growth law. The theoretical equations derived from the model readily account for experimental data for the growth of a passive film on iron. It is found that the field strength of the film is 1.11×106V/normalcm . The dependence of film/solution interface potential difference on the applied potential (α) was found to be 0.743, and is independent of the identity of the anion in solution. However, the dependence of the potential difference across the film/solution interface on the solutionpH (β) is strongly dependent on the identity of the solution anion.

Use of the point defect model to interpret the iron oxidation kinetics under proton irradiation

“…To evaluate E, we have used the Point Defect Model (PDM) 13,14,15,16 . The PDM has been developed for electrochemical experiments to interpret anodic oxide growths.…”

“…The iron oxidation kinetics under irradiation has been then obtained. The electric field influence in the corroded layer has been deduced using the Point Defect Model (PDM) [12][13][14][15][16] .…”

Influence of ethanol, acidity and chloride concentration on the corrosion resistance of AISI 316L stainless steel

“…For different stainless steels, this potential region was attributed to the increase in the thickness of the oxide film formed in region B. [17][18][19][20] Some works [20][21][22][23][24] considered that the film thickness increased linearly as a function of potential, and consequently the electric field remained constant (at ca. 10 6 -10 7 V cm -1 ) during the film formation process.…”

Construção de uma célula-autoclave para medidas eletroquímicas a altas temperaturas

“…Assim, com o aumento do potencial, a velocidade de transferência de carga na interface e o espessamento do filme aumentam devido à migração de cátions (M n+ ) da interface metal/filme para a interface filme/solução e migração de anions (O 2-) no caminho oposto. [9][10][11][12] Nos potenciais superiores a 0,4 V/fio de tungstênio ocorreu um aumento da densidade de corrente, que foi comprovado estar associada à transpassivação do aço pelo registro da corrente após a inversão do sentido da varredura de potencial. Com a inversão do potencial, a densidade de corrente diminuiu de forma exponencial com a diminuição do potencial.…”