Patent ID: 8883073

Claim:
A method of inhibiting corrosion on a galvanized metal surface wherein the galvanized metal surface is part of an industrial water system that is at least partially full of water, the method comprising: (a) adjusting the water in the industrial water system to have a pH from about 6.5 to about 8.2; (b) introducing an effective amount of a corrosion-inhibiting composition into the water of the industrial water system when said system is either under load or not under load, said corrosion-inhibiting composition including a sulfide-based white rust corrosion-inhibiting compound selected from the group consisting of bismuthiols and dimerized bismuthiols; (c) circulating the water of the industrial water system for a time interval to contact the sulfide-based white rust corrosion-inhibiting compound with the galvanized metal surface to form a barrier on the galvanized metal surface, if the system was not under load; (d) operating the system for a time interval to contact the corrosion-inhibiting composition with the galvanized metal surface to form a barrier on the galvanized metal surface, if the system was under load; (e) overlaying the barrier by: i) unloading the system, readjusting the pH of the water in the system to be from about 6.5 to about 8.2, reintroducing an effective amount of the corrosion-inhibiting composition into the water of said system, and circulating the water of the system, or ii) keeping the system under load, readjusting the pH of the water in the system to be from about 6.5 to about 8.2 and reintroducing an effective amount of the corrosion-inhibiting composition into the water of said system; and (f) operating the industrial water system under load for one or more additional time intervals and repeating step (e) after one or more of the additional time intervals.