| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for preventing corrosion in which zinc-base anticorrosive is not used but phosphorus-base anticorrosive is used and under state of restraining the bad effect to the circumference by reducing use concentration of the anticorrosive, good initial stage anticorrosive film can stably be formed and a water-treatment on and after forming the initial stage anticorrosive film is not affected. SOLUTION: In the initial stage anticorrosive film forming process for forming the initial stage anticorrosive film on the surface of an iron-base metal member in a water-system by adding the anticorrosive in the water-system, the anticorrosive containing one or more kinds selected from pyrophosphoric acid and/or its salt is used and initial stage anticorrosive film forming process is performed by adjusting the pH at the initial stage to 5 to <7 so that the pH at the finishing time becomes≥7. COPYRIGHT: (C)2006,JPO&NCIPI
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