A General Strategy towards Superhydrophobic Self-Cleaning and Anti-Corrosion Metallic Surfaces: An Example with Aluminum Alloy

Shunli Zheng,Quanli Li,Zhong Chen,Ying Cao,Tengfei Xiang,Yupeng Zhang,Cheng Li

doi:10.3390/coatings11070788

Abstract

Corrosion and contamination of metallic structures can cause loss of their functionality as well as aesthetic values. In this study, we describe a general strategy to prepare superhydrophobic self-cleaning and anti-corrosion surfaces for metallic structures. As a specific example, a superhydrophobic coating (SHC) on aluminum alloy was prepared by a simple etching combined with the decoration of a low-surface-energy material. The optimal SHC has a water contact angle (CA) at ~157.4° and a sliding angle (SA) of ~8.3° due to the synergy of binary hierarchical structures and chemical modification. The SHC showed low adhesion to dry contaminants and a series of liquids, displaying a good self-cleaning effect. The SHC maintained superhydrophobicity after exposure to air and humid condition at 60 °C for 7 days. In addition, the electrochemical measurements reveal that the anti-corrosion performance was enhanced by reducing the corrosion current density (Jcorr) by 1 order of magnitude and increasing the corrosion potential (Ecorr) by 0.527 V as compared to the bare Al alloy substrate after immersion for 168 h.

Highlights

The marine environment is aggressive and corrosive
The optimal etching time for obtaining the coating is 5 min when treated with HCl solution at 350 g/L concentration
The Al alloy substrate coated with myristic acid alone displays hydrophobicity with a contact angle (CA) of 113.1◦ ± 2.3◦

Summary

Introduction

The marine environment is aggressive and corrosive. Marine structures and many land structures that are made of metals and alloys are commonly exposed to ultraviolet radiation, chloride-rich liquid or deposit, frequent wet-dry cycles, high humidity and so on, which can accelerate the corrosion and degradation of the materials especially used in the offshore platform, drilling pipes, anchor, submarine cable and ship hulls, etc., leading to reduced service life or even causing disasters [1]. Along with corrosion, fouling is a big natural problem. Contamination and corrosion of metallic materials in severe environments are big issues in the world. There is a great demand to construct an effective corrosion-resistant and self-cleaning protective layer on metallic materials to expand their application fields and prolong their service life

Methods

Results

Conclusion