Closed Loop Corrosion Inhibition: Review of Industry Trends, Technology Gaps, And the Next Generation in Closed Loop Inhibition

Closed systems are found in a wide variety of applications, ranging from simple HVAC systems in residential buildings to increasingly complex manufacturing and heavy industrial production plants. This paper is broken down into 4 sections. First, traditional chemistries are reviewed including the most widely used mild steel corrosion inhibitors, molybdate and nitrite, with pros and cons fully discussed. The challenges of using borate compounds as buffer, under the EU REACH regulations are also discussed. Second, the trend of using aluminium alloys in aluminium boiler and plastic blow molds is covered along with the discussion of corrosion control challenges of different types of aluminium alloys. The third section discusses the needs for new closed system treatment programs because of the current treatment challenges, usage of new metallurgies and more stringent regulations. Lastly in the fourth section, we present next generation non-toxic closed loop corrosion control programs that demonstrate excellent corrosion inhibition and contain no nitrite, heavy metal, phosphorus, borate, or filming amine. Laboratory feasibility experiments will be presented that simulate a few of the representative application scenarios.