Galvanic corrosion is similar to a battery in the reaction principle of electrolysis process. Therefore, create galvanic corrosion will must have four  elements: the electrolyte, anode, cathode and the current channel. Two environmental conditions of relative humidity exceeds 60%, ambient gases such  as chlorine, nitrogen dioxide, sulfur dioxide is the presence of electrolytes two formed the main catalyst. High humidity makes water soluble gas to  condense the water vapor in contact with the surface, forming a conductive weak acid. ] dZ5N-f4 | localized to the anode and the cathode is composed  of contact surface coating layer crack or pore produced by. Microporous bottom base metal forms the anode, and the precious metal coating layer is  formed on the cathode. Finally, because of the coating layer, interface, base metal, electrolyte has a conductive, so the current channel is formed.  The corrosion rate and corrosion product related. Copper corrosion, microporous, makes the water continues to permeate. But it also react with water  to produce more compounds, and further accelerate the corrosion. Nickel corrosion is impervious to moisture, is tightly attached to the metal surface,  forming a layer of water vapor barrier layer. The results of electrochemical corrosion of nickel, often get self inhibition.