Introduction of an innovative corrosion-protective alkyd steel coating based on a novel layered aluminum tripolyphosphate loaded with 6-amino hexanoic acid (ATP-6-AHA)

Abstract

The novel hybrid phosphate pigment 6-amino hexanoic acid (6-AHA) intercalated in layered aluminum di-hydrogen tripolyphosphate (ATP-6-AHA) was successfully embedded in an alkyd coating at 5.0 wt% and applied on low carbon steel. Layered pigments used in coatings are becoming very attractive due to the improvement of the coatings barrier properties. The current study revealed superior corrosion protection of ATP-6-AHA coating on carbon steel with a polarization resistance of 1.3 108 Ohm·cm2 after three weeks immersed in a 3.5 wt% NaCl solution, using electrochemical impedance spectroscopy (EIS). The adhesion and surface roughness of coated samples were evaluated using pull of test and laser scanning microscopy. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to assess the corrosion protection of ATP-6-AHA alkyd coating. Results revealed a protective film on steel surface comprising iron phosphate.