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US 5,527,388 AGranted
Corrosion inhibiting formulations with calcium nitrite
AssigneeW. R. Grace & Co.-Conn.
InventorsNeal S. Berke, Ding F. Shen, Maria C. Hicks, Ellis M. Gartner
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Abstract
An admixture for cement compositions is provided which contributes both anodic and cathodic corrosion inhibition, and the cement compositions containing such additives. The cement additive is a combination of an anodic corrosion inhibitor such as calcium nitrite, and a cathodic corrosion inhibitor such as calcium stearate or other fatty acid. The mixed inhibitors in accordance with the invention provide as good or better corrosion inhibition than does calcium nitrite when used alone.
Claims8
A cementitious composition comprising:
- a. hydraulic cement;
- b. an alkali or alkaline earth metal nitrite in an amount of at least about 0.5% of the dry weight of said hydraulic cement in said composition;
- and
- c. a cathodic corrosion inhibitor selected from the group consisting of C.sub.17 to C.sub.21 organic acids, and salts and esters thereof;
- zinc salts;
- iron phosphate;
- and mixtures thereof,
- wherein said cathodic corrosion inhibitor and said alkali or alkaline earth metal nitrite are in a ratio of at least 0.01:1.
5 more elements
Dependencies are inferred from the claim text.