Resumo

LEON-BELLO, F.  e  AMAYA-MALPICA, M. G.. Surface galvanic action on a carbon steel matrix microcell consisting on ferrite and pearlite grains. Rev. Mex. Ing. Quím [online]. 2008, vol.7, n.1, pp.29-33. ISSN 1665-2738.

An irreversible thermodynamics model is proposed to estimate galvanic action on a heterogeneous polycrystalline matrix, made on ferrite and pearlite grains, in order to find engineering parameters to account for the effect of electrochemical reactions due to corrosion processes on carbon steel. The model is based on an open system representing the surface of the metallic matrix and the electrolyte. The galvanic action at microscopic scale is described by a system of equations that meets thermal diffusion and chemical co diffusion effects with entropy production due to both heat and diffusion fluxes. The application of the model requires an experimental validation on which adequate values for the phenomenological coefficients were found. The heterogeneous nature of the grains arrangement on the carbon steel surface corresponds to a heterogeneous mechanism of galvanic action so that the resulting engineering parameters are mean values of the magnitude on the extensive properties of the system.

Palavras-chave : galvanic action; carbon steel; electronic affinity; irreversible processes; local cell corrosion.

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