| 摘要 |
PURPOSE:To prevent effectively corrosion over a wide range even if the environment for using an Al material changes drastically in a titled method using an external power source by suppressing intermittently the cathode potential of the Al material in accordance with the cathode potential of said material with respect to a reference electrode provided in water. CONSTITUTION:A reference electrode 2 is provided in water in proximity to an Al material 1, which is a material to be protected and is immersed in the water. The cathode potential V of the material 1 with the electrode 2 as a reference is measured by a potential measurement device 3, via circuits 7, 7. A signal is emitted from the device 3 to a relay device 5 at every rise of the potential V to a preset upper potential Vu. A counter electrode 4 and the material 1 are connected, via the device 5, to an external power source 6, whereby cathode current circuits 8, 8 are formed. The circuits are normally held open but when the potential V rises up to the Vu, the device 5 is operated by the above-mentioned signal, by which the circuits 8, 8 are closed for a short time. The cathode current is run between the material 1 and the electrode 4 during this time and the potential V is intermittently suppressed. |
