Editing Corrosion (section)

==== Reactive coatings ====
If the environment is controlled (especially in recirculating systems), [[corrosion inhibitor]]s can often be added to it. These chemicals form an electrically insulating or chemically impermeable coating on exposed metal surfaces, to suppress electrochemical reactions. Such methods make the system less sensitive to scratches or defects in the coating, since extra inhibitors can be made available wherever metal becomes exposed. Chemicals that inhibit corrosion include some of the salts in [[hard water]] (Roman water systems are known for their [[Eifel Aqueduct#The aqueduct as a stone quarry|mineral deposits]]), [[chromates]], [[phosphate]]s, [[polyaniline]], other [[conducting polymers]], and a wide range of specially designed chemicals that resemble [[surfactant]]s (i.e., long-chain organic molecules with ionic end groups).