Sodium molybdate corrosion inhibitor for boiler feedwater systems

Journal Article · Thu Nov 01 00:00:00 EST 1979 · Ind. Water Eng.; (United States)

OSTI ID:6397662

Robitaille, D R

Molybdate-containing corrosion inhibotors are becoming more attractive in an increasing number of commercial applications. Sodium molybdate inhibits corrosion of low carbon steel, copper and brass in recirculating cooling water systems while being environmentally safe. These compounds are also economical at the concentration required for effective water treatment. Molybdenum is tolerated in various concentrations by many life forms. Molybdenum compounds are characterized as nontoxic in US Public Health Bulletin 293, by the Federal Hazardous Substances Labeling Act, and by the Occupational Safety and Health Act. The nature of molybdate inhibition was discussed. Molybdate inhibits by adsorption. This necessitates the use of more molybdate to protect steel in typical waters than is required for protection in distilled water. Sodium molybdate inhibition has been investigated in waters of varying composition and pH. Several multi-component inhibitor systems which contained sodium molybdate were studied. Several advantages of molybdates beyond general ferrous metals corrosion inhibition can be shown which have important commercial implications. These include inhibitions of pit propagation, and of crevice and nonferrous metals corrosion. The effect of sodium molybdate on the corrosion inhibition of copper was studied in soft water. Potentiodynamic polarization experiments were performed with aluminum in deaerated high chloride and high chloride + sodium molybdate solutions. The ability of a single chemical to inhibit the corrosion of more than one metal has important advantages in water treatment. Cost data indicate that molybdates are more cost effective than generally believed. 5 figures, 6 tables. (DP)

• OSTI ID: 6397662
• Journal Information: Ind. Water Eng.; (United States), Journal Name: Ind. Water Eng.; (United States)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BOILERS
FEEDWATER
CORROSION INHIBITORS
MOLYBDATES
SODIUM COMPOUNDS
BRASS
COPPER
ECONOMICS
IRON
WATER
WATER TREATMENT
ALKALI METAL COMPOUNDS
ALLOYS
COPPER ALLOYS
COPPER BASE ALLOYS
ELEMENTS
HYDROGEN COMPOUNDS
METALS
MOLYBDENUM COMPOUNDS
OXYGEN COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
ZINC ALLOYS
360105* - Metals & Alloys- Corrosion & Erosion