Why solenoid coil corrosion?

Why solenoid coil corrosion? Time solenoid coil terminal are due to poor seal into the water, and terminal corrosion phenomenon of all out on the anode, and the cathode is intact. This can determine, sealed electromagnetic valve coil and water is the leading cause of terminal corrosion. But because of the harsh working conditions on site, the coal on the impact of the coil is inevitable, so there is no guarantee that the coil terminal without water. Due to the terminal in the presence of water and water containing salt, act as the role of the electrolyte; So appeared a galvanic cell reaction to the cathode, in the process of electric wire coil, electronic all flow to the cathode and anode of the surface of the terminal corrosion current fell to zero or near zero, thus inhibiting the terminal electron, so as to prevent the corrosion of the terminal. This is the so-called impressed current cathodic protection. For the anode, the situation, on the other hand, it has become 'the sacrificial anode cathodic protection' in the sacrifice anode. So even if the chemistry is not lively copper, also quickly corrosion, terminal appear rupture, causing downtime