Table 1.

Interpretation of corrosion activity of electrochemical methods.

Corrosion Activity	Potential Level (mV) [53]	Resistivity (Ω·m) [51]	Corrosion Rate
			LPR (Icorr (A/cm2)) [39]	GPM (Rct (kΩ·cm2)) [39]
Very High	-	-	10–100	0.25–2.5
High	<−350	<100	1.0–10	2.5–25
Moderate/Middle	−200 to −350	100–500	-	-
Low	>−200	500–1000	0.1–1	25–250
Negligible/passive	-	>1000	<0.1	>250