ENGINEERING TECHNOLOGY

New progress has been made in the field of marine corrosion protection of superhydrophobic surfaces


Simulation of deliquescence behavior of sodium chloride monosalt particles and multi-salt particles in high-salt and high-humidity marine atmospheric environment Photo courtesy of the research group

Recently, the research group of researcher Hou Baorong-Duan Jizhou of the Institute of Oceanography of the Chinese Academy of Sciences has made new progress in the design and construction of fluorine-free environmentally friendly superhydrophobic coatings and their research in the field of marine corrosion protection. The relevant research results were published in the international academic journal Materials and Design.

Based on the unique interface non-wetting and liquid-repellent, bionic superhydrophobic materials show great application potential in the fields of surface self-cleaning, oil-water separation, anti-ice and frost, radiation refrigeration, droplet manipulation, anti-corrosion and anti-fouling. The structural support materials of various engineering facilities and equipment serving in the marine environment are mainly composed of metals and alloys, and due to the severity of the marine corrosion environment, metals and alloy materials will inevitably suffer corrosion failure, which will cause the performance of facilities and equipment to decay, huge economic losses, ecological environment damage, and even sudden safety accidents.

The air layer trapped in the gap of the superhydrophobic material structure can make it have a very low liquid-solid contact area at the multiphase interface, thereby improving the surface charge transfer resistance and inhibiting the internal penetration and diffusion of the corrosive electrolyte, which provides a solution to the marine corrosion problem of metal and alloy materials. However, at present, superhydrophobic protective materials face problems such as fragile micro-nano multi-scale structure, the use of fluorine-containing reagents, complex preparation processes, and poor mechanical stability, and their interface interaction mechanism in the field of marine corrosion protection in different zones needs to be deeply understood.

By selecting zinc oxide nanoparticles, stearic acid and polydimethylsiloxane as raw materials, the researchers prepared a ZnO@STA@PDMS-free superhydrophobic protective coating with good mechanical stability, thermal stability and interfacial adhesion in the metal matrix based on simple and efficient surface spraying technology.

In addition, by simulating and observing the deliquescence behavior of sodium chloride single and multi-salt particles in the high humidity marine atmosphere, the researchers found that the corrosion at the boundary of the salt deliquescence zone was significantly faster than that in the central zone, mainly due to the priority deliquescence and abundant oxygen content at the boundary, which in turn accelerated the local corrosion behavior of chloride ions. At the same time, the researchers proposed for the first time that there is a potential salt deliquescence self-fusion protection mechanism in the high-salt and high-humidity marine atmospheric environment of superhydrophobic surfaces, and the extremely low surface energy and adhesion of the multiphase interface and its repulsion of sodium chloride droplets after deliquescence provide interface advantages for the application of such materials in marine atmospheric corrosion protection.

In addition, the coating exhibits good mechanical stability, thermal stability, green environmental protection, low cost, and wide application range of substrates, which makes it a potential solution for corrosion failure suppression of material surfaces in marine and industrial environments.

Zhang Binbin, associate researcher of the Institute of Oceanology, Chinese Academy of Sciences, is the first author and corresponding author of the paper. The research work was supported by the Youth Innovation Promotion Association of the Chinese Academy of Sciences, the Shandong Outstanding Youth Science Foundation and the Key Project of the Shandong Provincial Joint Fund. (Source: China Science News, Liao Yang, Li Hezhao)

Related paper information:https://doi.org/10.1016/j.matdes.2022.111246



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