SEDL / STP / STP978-EB / STP26199S

The Effect of Soil Resistivity and Soil Temperature on the Corrosion of Galvanically Coupled Metals in Soil

Escalante, E
Metallurgist, Corrosion Group, National Bureau of Standards, Gaithersburg, MD

Pages: 10    Published: Jan 1988

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Abstract

Galvanic corrosion current measurements carried out on stressed Type 301 stainless steel coupled to zinc at six underground test sites over a period of four years indicate that the galvanic current is controlled by soil resistivity or oxygen availability in the soil. In well aerated soils, resistivity plays a dominant role, but in poorly aerated soils, oxygen controls the corrosion process. Furthermore, at a certain depth, approximately 1 m, soil resistivity is strongly influenced by soil temperature and only slightly affected by soil moisture. Finally, Type 301 stainless steel in a half-hard or full-hard condition is susceptible to hydrogen embrittlement failure in soil when exposed to potentials capable of causing hydrogen evolution.