Interactive Resource icon  Filliform Corrosion Mechanism

 
Use this resource: Use this resource icon
Link to this page: http://core.materials.ac.uk/search/detail.php?id=2869
View at:        
Resource type: Interactive Resource
Description: The filament propagates by anodic undermining. This means that the aluminium surface at the front of the filament just below the coating is corroded away. The coating detaches from the substrate and is pushed up by the corrosion products that form in the tail. In this way the filament grows. When the aluminium ions hydrolyse, hydrogen ions are formed, acidifying the tip. The hydrogen ions are reduced at the tip forming hydrogen gas. The main cathodic reaction takes place just behind the anode and is the oxygen reduction on the intermetallics that are present at the surface. Chlorides (or other cations) provide electroneutrality in the tip. The aluminium ions and hydroxide ions form insoluble aluminium-hydroxides in the tail. This animation expalins the mechanism of filiform corrosion.
Keywords: filliform corrosion • fillament • organic coating • anodic undermining • cathodic reaction
Categories: Science approaches > Corrosion & degradation
Science approaches > Corrosion & degradation > Forms of corrosion
Materials > Metals & alloys > Aluminium & alloys
Created by: MATTER, The University of Liverpool
Steven Meijers, Corus
Carlos Caicedo-Martinez, Corus
Contributions: Andreas Blistein, Alcan
Herman Terryn, Vrije Universiteit Brussel (VUB)
Iris De Graeve, Vrije Universiteit Brussel (VUB)
Marc Ryckeboer, Sapa
Published by: European Aluminium Association, Brussels
License: This resource is released under the Creative Commons Attribution Non-Commercial No Derivatives license (2.0 UK: England & Wales).
Creative Commons Attribution Non-Commercial No Derivatives logo
You are free:
  • to share – to copy, distribute and transmit the work
Under the following conditions:
  • attribution – You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work).
  • noncommercial – You may not use this work for commercial purposes.
  • No Derivative Works – You may not alter, transform, or build upon this work.
View the full legal code here.
Date created: 12 August 2005
Date added: 07 July 2010
Package:
Resource ID: 2869