Surface corrosion

from Wikipedia, the free encyclopedia

Uniform surface corrosion occurs when the corrosion process occurs on all or a large part of the component surface. Anodic (metal dissolving) and cathodic (electron consuming) sub-areas are formed on the metal surface . The prerequisite for the formation of surface corrosion is the constant change of location of these sub-areas. Only then can the corrosion run smoothly on the metal surface. If this change in position of the sub-areas is not possible or is only possible with difficulty, one speaks of trough corrosion.

In the case of surface corrosion in neutral areas, depending on the material, a cover layer ( passive layer ) can arise on the metal, which greatly reduces the susceptibility to corrosion or prevents or limits the corrosion itself. If the passive layer has not formed in some places or if it has been destroyed by acid attack (intensified by chloride ions ), this also leads to pitting or pitting corrosion .

Surface corrosion is classified as rather harmless corrosion, as it can be detected early and only leads to damage when the loss of mass of the metal is sufficiently large. If the intensity of the subsequent exposure to atmospheric gases , acids, etc. is known, the sacrificial layer can be adequately dimensioned. In this way, the safety of a component is also guaranteed in the long term.

literature

  • Karl-Helmut Tostmann: Corrosion. Causes and Avoidance. Wiley-VCH Verlag, Weinheim 2001, ISBN 3-527-30203-4 .
  • Kirsten Bobzin: Surface technology for mechanical engineering. 1st edition. Wiley-VCH Verlag, Weinheim 2013, ISBN 978-3-527-33018-8 .
  • Klaus H. Weber: Engineering of process engineering systems. Practical manual with checklists and examples. 2nd Edition. Springer Vieweg, Berlin 2016, ISBN 978-3-662-52896-9 .

Web links