Highly efficient anti-corrosion polyetherimide (PEI) coating encapsulated with aluminum di-hydrogen tri-polyphosphate

Protective composite coatings based on polyetherimide (PEI) incorporated with aluminum di-hydrogen tri-polyphosphate (ATP) particles for the protection of carbon steel are reported here. The ATP particles were used as an inhibiting pigment. The layers were applied by the dip coating method leading to a full uniform coverage as confirmed by microscopic and Raman spectroscopy techniques. The anti-corrosion characteristics of the PEI-coated samples were investigated in a 3.5 wt.% NaCl solution by electrochemical impedance spectroscopy. The results revealed that PEI-ATP composite coating exhibited higher impedance values above 109 Ω.cm2 (up to 30 days) compared to a Blank-PEI coating. The active protection was studied by the scanning vibrating electrode technique revealing clear signs of inhibition in the artificial defects. The proposed mechanistic insights into the protective properties of PEI-ATP coating was further supported using X-ray photoelectron spectroscopy.