It is generally referred to as a steel native potential or a free corrosion potential, although it can also be an instant off-potential, a decayed off-potential, or a rest potential.
For instance, a decayed off-potential or a rest potential with insufficient depolarization time may still be more negative than the native potential, or fall below the potential range shown in Figure 2 due to prior cathodic polarization.
A chart was developed in this work to quantitatively map the rule-of-thumb relationship between steel native or rest potentials and soil resistivity.
Nevertheless, if the steel native or rest potentials can be known, the level of cathodic polarization applied on the steel pipe surface for a given off-potential can be evaluated and provides a more direct measure (than an off-potential) on the magnitude of corrosion rate reduction.
The meanings of on- and off-potentials, polarization (decay or growth) and ohmic voltage drop (IR), native and rest potentials are labeled and shown clearly.
Figure 4 shows the native or rest potentials of operating pipelines or installed coupons vs.
5 produced a slight hyperpolarization of rest potential by about 1 mV.
The ionic model that we propose for the spontaneous activity is novel and counterintuitive, in that the effect is attributable to a reduction of inward current, thereby leading to a destabilization of the rest potential by the [I.