Sodium molybdate as a corrosion inhibitor of mild steel in natural waters Part 2: Molybdate concentration effects
- Univ. of Virginia, Charlottesville, VA (United States). Center for Electrochemical Science and Engineering
Sodium molybdate (Na[sub 2]MoO[sub 4]) is one of many proposed replacements for chromate-based inhibitors of steel corrosion. However, its ability to protect steel in natural waters, especially flowing natural waters, has not been examined in detail. Part 1 of this study detailed effects of flow rate on the corrosion rate of rotating cylinder electrodes (RcE) of ASTM A36 steel (UNS K02600) exposed to 125 ppm Na[sub 2]MoO[sub 4] solutions under different flow conditions. Part 1 also discussed limitations of electrochemical impedance spectroscopy (EIS) as a method of examining electrochemical behavior in low-conductivity environments. Part 2 examined the behavior of A36 steel RCE exposed to various concentrations of Na[sub 2]MoO[sub 4]. For polished samples, a critical concentration of Na[sub 2]MoO[sub 4] existed, beyond which the corrosion rate increased. However, no critical concentration existed for samples that possessed a corrosion product prior to the addition of inhibitors. Oscillatory open-circuit potential behavior and EIS measurements suggested periodic active/passive transitions on pre-corroded samples.
- OSTI ID:
- 5987972
- Journal Information:
- Corrosion (Houston); (United States), Journal Name: Corrosion (Houston); (United States) Vol. 49:8; ISSN 0010-9312; ISSN CORRAK
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360105* -- Metals & Alloys-- Corrosion & Erosion
ALKALI METAL COMPOUNDS
ALLOYS
BIOLOGICAL FOULING
CARBON STEELS
CHEMICAL REACTIONS
CONCENTRATION RATIO
COOLING SYSTEMS
CORROSION
CORROSION INHIBITORS
CORROSION PROTECTION
ENERGY SYSTEMS
FLOW RATE
FOULING
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS TESTING
MOLYBDATES
MOLYBDENUM COMPOUNDS
OXYGEN COMPOUNDS
PERFORMANCE TESTING
REFRACTORY METAL COMPOUNDS
SODIUM COMPOUNDS
STEELS
SURFACE WATERS
TESTING
TRANSITION ELEMENT COMPOUNDS