Layered aluminum tri-polyphosphate as intercalation host for 6-amino-hexanoic acid - Synthesis, characterization and application as corrosion protection inhibitor for low carbon steel

Developing efficient inhibitors based on eco-friendly compounds for steel protection is crucially important. Here the synthesis and characterization of a new hybrid inhibitor based on intercalation of 6-aminohexanoic acid (6-AHA) in layered aluminum tri-polyphosphate (ATP) are reported. ATP and the inorganic-organic hybrid inhibitor system ATP-6-AHA are characterized by XRD, thermal gravimetric analysis (TGA), SEM, IR and Raman spectroscopy. The interlayer space of ATP is expanded by 10.1 angstrom, with 6-AHA planes arranged in bilayers. Corrosion efficiency of ATP-6-AHA was evaluated in 0.1 M and 3.5 % NaCl using electrochemical impedance spectroscopy (EIS) and showed a significantly reduced corrosion for steel S235.