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CORROSION CONTROL BY CATHODIC PROTECTION. THEORETICAL AND DESIGN CONCEPTS FOR MARINE APPLICATIONS

The history and theory of cathodic protection are reviewed. Cathodic protection design mainly amounts to straight-forward electrical engineering. The most difficult exercise is the estimation of current requirements which generally must be based on long experience. Obtaining an economical life form impressed current "permanent" anodes is less of a problem following the developments of the versatile platinized titanium and lead alloy anodes. Advances in aluminum alloy sacrificial anodes throw a new light on this method of protection in marine environments. The design procedure outlined is a simple solution of Ohm's Law--having estimated I, find a suitable combination of E and R. With sacrificial anodes E is limited to a specific value according to the alloy used. With impressed current the design is more involved but nevertheless the same basic procedure holds. Effects such as interference corrosion, coating destruction and hydrogen embrittlement can be catastrophic unless eliminated at the design stage. Technical difficulties or economic considerations, however, will rarely exclude cathodic protection, either solely or in conjunction with coatings, as a totally effective method of corrosion control where this degree of corrosion control is warranted.

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Filing Info

  • Accession Number: 00019229
  • Record Type: Publication
  • Source Agency: Engineering Index
  • Files: TRIS
  • Created Date: Nov 25 1972 12:00AM