Article Dans Une Revue Journal of the Less Common Metals Année : 1980

Potentiostatic investigation of the evolution of the cathodic current, near the corrosion potential, of a titanium rotating disc electrode in aerated sulphuric acid medium

Résumé

Two titanium samples were investigated from a mechanistic standpoint under conditions where two coupled reduction processes coexist, the reduction of protons and of dissolved oxygen, the latter taking place chemically to the detriment of hydrogen absorbates weakly bonded to the substrate. Comparison of the samples was performed with a titanium rotating disc electrode, on the basis of the diffusional and non-diffusional components of the overall cathodic current. These were determined by analysing the variation of the overall potentiostatic current with rotation speed at a given moment. The experimental results are consistent with an interpretation based on the theory of diffusion to partially blocked surfaces, i.e. surfaces at which only certain sites are active from a diffusional viewpoint. It was thus shown that the nature of the titanium sample (purity, surface state etc.) conditions the energy of the substrate-absorbed hydrogen bond and thus the reaction rates at a local level. This generates quantitative differences in the patchwise topography of the active sites. The origin of this topography is shown to lie in the existence of certain mechanisms at the interface involving interactions between neighbouring absorbates. The differences between the bonding energies also give rise to differences in the nature of the hydrogen recombination step which can be chemical or electrochemical depending on the titanium sample.

Domaines

Chimie

Dates et versions

hal-04739672 , version 1 (16-10-2024)

Identifiants

Citer

Adrien Caprani, Israël Epelboin, Ph. Morel. Potentiostatic investigation of the evolution of the cathodic current, near the corrosion potential, of a titanium rotating disc electrode in aerated sulphuric acid medium. Journal of the Less Common Metals, 1980, 69 (1), pp.37-48. ⟨10.1016/0022-5088(80)90042-9⟩. ⟨hal-04739672⟩
13 Consultations
0 Téléchargements

Altmetric

Partager

More