SEDL / STP / STP32-EB / STP47833S

An Electrical Resistance Method of Determining Corrosion Rates

Seeber, R. R.
Professor of Mechanical Engineering, Michigan College of Mining and Technology, Houghton, Mich.

Pages: 6    Published: Jan 1937

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Abstract

The use of the increase of the resistance of a specimen to determine its corrosion penetration is not new. Early use of this method was made by Wilson. Later, Hudson made tests with the method to determine its accuracy, and used it extensively in his study of atmospheric corrosion. The following discussion deals with the application of the resistance method of corrosion measurement in a tight iron pipe steam system. The method is basedupon the proved principle that the resistance of a uniform conductor varies inversely as the area of its cross-section. The fact that the products of corrosion have such a high resistance as compared with the resistance of the conductor itself makes it possible to measure the true resistance of the metal itself without first cleaning it. This has a distinct advantage over the gravitational method, which requires that the specimen be thoroughly cleaned without removing the metal itself. In order to measure successfully the amount of corrosion by the change of the resistance of a specimen it is necessary to take account of the following factors: 1. Contact resistance. 2. Type of specimen and holder. 3. Temperature effects.