Hyperbranched molecules having multiple functional groups as effective corrosion inhibitors for Al alloys in aqueous NaCl

Abstract

Hyperbranched molecules are a kind of promising materials due to their unique structures. In this work, two hyperbranched molecules (GON and GOH) are used as effective inhibitors for Al alloys in NaCl solution. Their inhibitive performances are evaluated by electrochemical measurements and surface characterization. The results indicate that inhibition performances of GON and GOH are closely related to the concentrations, influenced by the combination of steric hindrance and bonding effects. At relatively low concentrations (0.03–0.10 mM), GON displays a more pronounced ability to inhibit corrosion than GOH, owing to more anchoring functional groups. Oppositely, GOH has good inhibition performance at higher concentrations (0.50–1.00 mM). The interaction between the Al electrode and GOH results in the formation of a more condenser protective film than GON at high concentrations. In addition, the adsorption mechanism of two hyperbranched molecules is revealed by theoretical calculations.