Vapour phase assembly of ultrathin coatings from alanine ternary complex on the carbon steel surface with enhanced corrosion resistance

ABSTRACT A novel alanine ternary complex (ALA-T) is prepared by the reaction of alanine (ALA), phosphoric acid, and dibutylamine. FTIR technique is used to characterise its structure. The weight-loss experiments in the closed space study the volatility of the alanine ternary complex. The ultrathin coating is formed on the surface of carbon steel by vapour phase assembly of the alanine ternary complex. The thickness of the coatings is measured using spectroscopic ellipsometry. The inhibition effect of ultrathin coatings on the corrosion of carbon steel is studied by the volatile-inhibiting ability (VIA) and the electrochemical tests. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) are utilised to examine the morphology and composition of the carbon steel surface. It shows that the complex ultrathin coating has good corrosion inhibition for carbon steel. The protection mechanism of the ultrathin coating is discussed and analysed.