| 摘要 |
PURPOSE:To provide long-term cathodic protection to an aluminum material in a wide range over the entire part thereof by impressing intermittently and repeatedly a negative pulse voltage via a sacrificial anode or outside electrode to the aluminum material dipped in water. CONSTITUTION:A sacrificial electrode 2 consisting of a metal such as zinc, magnesium or the like having the natural potential in water lower than that of an aluminum material 1 is provided in proximity to the material 1 as a material which is to be protected and is dipped in water. Said electrode and the aluminum material are connected by a conductor via a current interrupting device 3 to form cathodic current circuits 4, 4. A negative pulse voltage is intermittently and repeatedly impressed to the material 1 by the device 3 to suppress intermittently the cathodic potential. Then even if the negative voltage to be impressed to the material 1 is made substantially large, there is no possibility of inducing alkali corrosion and the satisfactory cathodic protection of the material 1 is accomplished. |
