| 摘要 |
PURPOSE:To elongate the life of an anticorrosive valve or joint, especially the life of a galvanic anode by plating the inside of the valve or joint using a metal which is baser than iron as the galvanic anode with a metal which is nobler than iron and has specified hardness. CONSTITUTION:The inside of an anticorrosive valve or joint using a metal having lower potential than iron as a galvanic anode is plated with a metal having higher potential than iron and >=800 Vickers hardness. For example, the inside of an anticorrosive iron-base valve or joint of cast iron or carbon steel using Mg, Zn or Al as a galvanic anode is plated with an alloy of Ni and/or Co and P and/or B. When an aqueous electrolyte soln. such as sea water is passed through the valve or joint, the mechanical strength of the plated hard metallic film prevents the erosion due to flowing water, and the dissipation of the galvanic anode is reduced to elongate the life. |
