Inhibition by phosphates of mild steel and cast iron in cooling water

The effectiveness of corrosion inhibition of mild steel and cast iron in cooling water systems by phosphonates has been studied by electrochemical techniques and weight-loss tests. The following phosphonates were investigated: aminotrimethylene phosphonate (AMP), 1-hydroxyethylene 1,1-diphosphonate (HEDP), and 2-phosphonobutane 1,2,4-tricarboxylic acid (PBTA). It was shown that corrosion inhibition of mild steel can be achieved with lower concentrations of phosphonates as compared to corrosion inhibition of cast iron. BC-80, a new inhibitor that protects mild steel, cast iron, and copper alloys in cooling water systems, was developed and tested in laboratory and field conditions.