| 摘要 |
PROBLEM TO BE SOLVED: To provide a corrosion prevention method capable of effectively preventing the corrosion of a metallic material in a cooling water system without using phosphorus based chemicals and zinc based chemicals at all. SOLUTION: In the corrosion protection method, in a cooling water system, water quality is controlled so that, provided the M alkalinity of the cooling water is AmgCaCO<SB>3</SB>/L; the hardness of calcium is BmgCaCO<SB>3</SB>/L; the concentration of silica is CmgSiO<SB>2</SB>/L; the hardness of magnesium is DmgCaCO<SB>3</SB>/L; a Langelier index is E; a hydrogen ion index is pH; and water temperature is t°C, (1) 2.4logA+logB≥6.4 and C≥50, (2) logC+logD+2pH+8.51logt≥33, or (3) logB+logC≥3.4 and E≥1.5 is satisfied. COPYRIGHT: (C)2004,JPO
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