Patent ID: 6998092

Claim:
A method for inhibiting corrosion of a metallic substance in an aqueous cooling water system containing soluble SiO 2 of greater than 10 mg/L wherein said aqueous system derives water from make-up source water, comprising the steps: a) removing hardness ions from said source water; b) controlling the ionic strength of the aqueous system water such that said aqueous system water possesses a measurable conductivity of at least 1 μmhos; c) elevating and maintaining the pH of said aqueous system water such that said aqueous system water possesses a pH of approximately 9.0 or greater; and d) cyclically contacting said aqueous system water with said metallic substance, wherein said pH and ionic strength increases the amount of soluble silica in the multimeric form present in said aqueous system water and inhibits corrosion of said metallic substance.