An active metal (such as zinc or an alloy of zinc) is connected to a protected metal so that, when electrochemical erosion occurs, the active metal acts as a negative electrode to oxidize, thereby reducing or preventing the erosion of the protected metal. This method is often used to protect steel piles in the water and the hull of sea vessels such as the protection of steel gates in the water, usually in the hull of a ship below the waterline or near the propeller to weld a number of pieces of zinc, to prevent erosion of the hull, etc.

In addition, there is: 'impressed current protection'. Connect the protected metal to the negative electrode of the power supply and another inert material that can conduct electricity to the positive electrode of the power supply. Electricity, so that the metal surface negative charge (electron) accumulation, so that the metal loss of electrons to achieve the purpose of protection. This method is mainly used to prevent erosion of metal equipment in soil, sea water and river water. Another method of electrochemical protection is called anode protection, that is, through the applied voltage, the anode passivation process occurs in a certain potential range. Can effectively block or prevent metal equipment in acid, alkali, salt erosion.