Designing Surface Morphologies and Anti - corrosion Properties of Anodized Aluminum Alloys via a Chemical Etching Method

To improve corrosion resistance performance of aluminum alloy,micro/nano-structures were formed by chemical etching and anodic oxidation methods on the surface of aluminum alloy.Then,anodic oxidation films with excellent anti-corrosion performance were obtained after being chemically modified via a self-assembly layer to improve the corrosion resistance of aluminum alloys.The surface morphologies and chemical elements of the as-prepared films were investigated by infrared spectroscopy and SEM.The values of surface roughness were measured by laser scanning confocal microscope.The hydrophilic/hydrophobic and anti-corrosion properties of the films were characterized by optical contact angle meter and electrochemical workstation.The influence of etching time on the surface morphologies and anti-corrosion performance was investigated.The results show that when the etching time is 3min,the film owns the best corrosion resistance performance,the corrosion potential shifted 0.15 V positively,the corrosion current density decreased two orders of magnitude compared to bare aluminum alloy,and the static contact angle is 152°at its maximum which is due to the intact and suitable ratio of the micro/nano-structure of the films under this preparation condition.