Some Factors Involved in Soil Corrosion E. R. SHEPARD, 3423 Connecticut Ave., Washington, D. C.
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While soil resistivit’y is known HE mechanism of corroLaboratory experiments on the causes and to be an i n i p o r t ’ a n t factor in sion, and p a r t i c u l a r l y mechanism of soil corrosion qf ferrous materials soil corrosion, the form of the that of soil corrosion, inare described. -An unbroken mill scale has a c i r c u i t , as determined by t,lie volving as it does a variety of protectiije injluence, [chile a discontinuous rnill geometric relations of the anode factors and their relations to one scale m a y facilitate pitting. and cathode areas involved, is of another, is a problem which has occupied the attention of investieven greater importance. The presence and distribution of oxygen in a The c o r r o s i o n prolilem is gators for many years; yet no soil is a n important factor in soil corrosion. f u r t h e r c o m p l i c a t e d by the satisfactory explanation for all Unequal disfribution of oxygen occurs in dry or time element. With t’hepassage of the observed phenomena has porous soils uhere a nonuniform condition of the of current, several effects occur. been offered. The present paper soil aggregate exists. Such conditions giite rise The first of t h e s e s e c o n d a r y lays no claim to new discoveries effects which tend to reduce the but is a brief presentation of the to local gulcanic action o n buried iron pipes. results of a series of laboratory rate of corrosion is more or less I n most soils the m a x i m u m rate of corrosion experiments which h a v e b e e n vaguely d e s c r i b e d under the occurs when the soil is moist rather than wet or carried out for the purpose of g e n e r a l t e r m “polarization.” saturated. T h i s is becauee of the limited supply studying several factor. in
