Composition and growth mechanism of nanoporous anodic fluoride films on stainless steel

Anodizing of 304L stainless steel performed in ethylene glycol solution containing 0.1 M NH4F and 0.1 M H2O at constant voltage under static conditions at 5 °C results in the formation of porous anodic films. Several analysis techniques revealed a rather complex composition of the anodic layer for s...

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Detalles Bibliográficos
Autores: Conde del Campo, Ana, Voces, Daniel, Damborenea, Juan de, Arenas, M. A.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2023
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/340451
Acceso en línea:http://hdl.handle.net/10261/340451
Access Level:acceso abierto
Palabra clave:SS 304L
Anodic layer
Fluoride
Efficiency
Descripción
Sumario:Anodizing of 304L stainless steel performed in ethylene glycol solution containing 0.1 M NH4F and 0.1 M H2O at constant voltage under static conditions at 5 °C results in the formation of porous anodic films. Several analysis techniques revealed a rather complex composition of the anodic layer for stainless steel compared to that reported in the literature for iron in the same anodizing conditions. Contrary to what might be expected, the anodic layers consist mainly of iron and chromium fluorides rather than oxides. Furthermore, the multilayer fitting of the Rutherford Backscattered spectroscopy shows a decreasing content of chromium and nickel fluorides from the outermost layer to the innermost layer at the metal/film interface, which is composed only of iron fluoride. Film-assisted dissolution mechanisms and the Gibbs-free energy appear to be responsible for the cation distribution and compounds formed throughout the anodic film. In addition, the thickness and final composition of the anodic layer appear to be dependent on the cleaning process carried out after the anodizing.