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This post was last edited by Wang Wei2 on 2025-12-31 10:34. Electrodelectric corrosion: A type of local corrosion that occurs when two metals are in contact within the same medium, resulting in an accelerated corrosion rate of the metal with the lower potential, while the corrosion rate of the metal with the higher potential decreases. The potential difference between the two metals is high ↑, resulting in a higher tendency for galvanic corrosion ↑. Cathode area increases ↑, anode area decreases ↓, anode corrosion increases ↑. “\"Electrode sequence\" — a table arranged in order according to the standard electrode potentials of metals. Standard electrode potential: The electrode potential when a pure metal is in equilibrium with the ions of that metal present in the medium. “\"Electrode sequence\" — a list arranged according to the relative magnitudes of the corrosion potentials measured for metals in specific media such as seawater. The electromotive series is used to determine the tendency of metal corrosion, while the galvanic series is used to determine whether galvanic corrosion will occur and to identify which electrode acts as the anode. The couple sequence can only indicate the possibility of galvanic corrosion; it cannot determine for sure whether galvanic corrosion will indeed occur or what its rate of occurrence will be. Since the relative corrosion tendency of metals in many environments is generally similar, the \"couple sequence of metals or alloys in seawater\" can be used to preliminarily determine the approximate direction of corrosion current in other environments, though exceptions do occur frequently.