Corrosion‐resistant coating of iron: A synergistic effect of electroactive poly(triphenylamine) coating with posttreatment for high‐corrosion‐protection efficiency

AbstractAn electroactive poly(triphenylamine) (PTPA‐C6) is applied to the surface of iron as a corrosion‐protection layer. The iron substrate coated with PTPA‐C6 is thermally treated at different temperatures (up to 80°C) to study the effect of thermal treatment of PTPA‐C6 on the corrosion behavior of iron. Experimental results indicate that the contact angle of the PTPA‐C6 film increases from 81.6° at room temperature to 100° after thermal treatment at 80°C for 1 hr. The surface becomes more hydrophobic after thermal treatment, which will lower the penetration of water to the iron surface. Adhesion tests (ASTM 3359) indicate that adhesion between the PTPA‐C6 and iron substrate is enhanced after thermal treatment. Additionally, a thin iron oxide layer formed between the PTPA‐C6 and iron substrate as a passivation layer. The synergistic effect of these factors makes PTPA‐C6 a very effective corrosion protection layer on iron substrate after appropriate thermal treatment. Corrosion protection efficiency increases from 90% of the pristine PTPA‐C6 to 99.9% of the 80°C treated PTPA‐C6.