Influence of multilayered polymer coatings on the corrosion behaviour and microstructures of Al6061-T6 alloy

Abstract

The influence of multilayered polymer coatings on the corrosion and microstructural properties of Al6061-T6 alloy was investigated. The electrochemical properties were determined in chloride solution via corrosion tests and electrochemical impedance spectroscopy (EIS) technique at room temperature. The microstructural properties and corrosion mechanism after polarization were studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM)/Kelvin probe force microscopy (KPFM) techniques. From the corrosion tests and SEM-AFM/KPFM analysis, the multilayered polymer coated (using polyacrylic acid - PAA) Al6061-T6 alloy experienced a positive shift in the corrosion potential (-0.648 V), signifying a possible corrosion protection ability. With a charge transfer resistance of 2.506×10−6 Ω cm2, and lesser corrosion products featured on the coated sample, the present work demonstrates that the deposition of multilayered polymer PAA coating can enhance the corrosion resistance of Al6061-T6 alloy.