Molybdate and nitrite as corrosion inhibitors for copper-coupled steel in simulated cooling water
- Rajshahi Univ. (Bangladesh). Dept. of Applied Chemistry and Chemical Technology
The use of molybdate (MoO{sub 4}{sup 2{minus}}) and nitrite (NO{sub 2}{sup {minus}}) as corrosion inhibitors for mild steel galvanically coupled to copper was investigated. In simulated cooling water (SCW), galvanic contact of copper is harmful to mild steel in acidic and alkaline pH ranges from 3 to 12. Galvanic contact is very harmful when MoO{sub 4}{sup 2{minus}}, NO{sub 2}{sup {minus}}, or both are present at low pH, but it becomes less harmful or even beneficial as pH increases toward the alkaline region. MoO{sub 4}{sup 2{minus}} alone in SCW was shown to inhibit corrosion of copper-coupled mild steel at pH {ge} 6, and nitrite was shown to do the same at pH {ge} 4.5. Below these values, both accelerated galvanic corrosion. Synergistic corrosion inhibition by the inhibitors was obtained at pH > 6. Galvanic contact of copper was shown to be beneficial to mild steel when the system was inhibitive.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 187037
- Journal Information:
- Corrosion, Journal Name: Corrosion Journal Issue: 1 Vol. 52; ISSN 0010-9312; ISSN CORRAK
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
CHROMATES
COOLING SYSTEMS
COPPER
CORROSION INHIBITORS
CORROSION PROTECTION
ELECTROCHEMICAL CORROSION
EXPERIMENTAL DATA
INDUSTRIAL PLANTS
MATERIAL SUBSTITUTION
MATERIALS TESTING
MOLYBDATES
NITRITES
PH VALUE
STEELS
WATER CHEMISTRY