An article published in the journal Chemistry and physics of materials describes a unique method of improving the anti-corrosion properties of carbon steel.
Study: Manufacture of a super-hydrophobic Ni–Co/Cu coating with improved corrosion resistance. Image Credit: Guilbaud Stan/Shutterstock.com
Researchers used electroplating, chemical oxidation and surface trimming to create an ultra-hydrophobic Ni-Co/Cu nanocomposite lamination that can be applied to carbon steel surfaces.
Scanning electron microscopy (SEM), X-ray diffraction (XRD), and water contact angle assessments were used to study surface properties, structures, and wetting characteristics. The results showed that the water contact angle increased to 158.61°, indicating ultra-hydrophobic character.
Carbon Steel Corrosion and How to Prevent It
Due to its decent mechanical qualities and low cost, high strength carbon steel is frequently used in marine engineering. However, its poor corrosion resistance even under moderate operating conditions limits its applicability.
Corrosion can reduce bearing capacity by decreasing its overall size or digging in, leading to massive economic losses and accidents.
Preservative coating or lamination is the most widely used anticorrosive technology among contemporary corrosion prevention technologies, which include cathodic shielding, anticorrosive materials, and coating. Electroplating is one of the most industrially feasible and cost-effective processes for producing metal, alloy, and metal matrix nanoscale composite coatings.
Use of nickel-based nanocomposites
Nickel (Ni) is a popular type of electroplating metal. The main disadvantages of electrodeposited Ni include its low firmness and limited wear resistance.
Researchers have created nanoscale Ni-based composite coatings, such as Ni-CeO2 coating, to increase the performance of nickel coatings. Making many alloy coatings is another way to improve Ni coating performance. Due to its high resistance to wear and corrosion, the nickel-cobalt (Ni-Co) alloy layer created by electrochemical deposition is essential for the protection of carbon steel. Ni-Co alloy coatings are also more corrosion resistant than Ni coatings.
The inclusion of cobalt atoms causes a deformation of the solid solute framework and a decrease in porosity, which increases the corrosion resistance of the coating. However, the presence of defects such as pitting and hemp points require further improvement in the surface quality and anti-corrosion behavior of nickel-cobalt coatings.
Ultra-hydrophobic Ni-Co lamination has piqued many people’s curiosity in recent years due to its ability to prevent the ingress of corrosive fluids and provide superior corrosion protection.
It is generally recognized that the most important variables in the formation of a super-hydrophobic surface are unique nanostructures and minimum surface energy. By modifying the surface using organic compounds such as 1-dodecanethiol and silane, low surface energy can be easily achieved.
Building a good rough structure is a critical topic for research, and since more complex parameter control is required, obtaining a sufficiently rough nanostructure surface via electrochemical techniques is much more difficult. Additionally, creating rough surfaces requires a higher overvoltage which can have a detrimental effect on the protective effectiveness of the coating.
The fabrication of the rough microstructures greatly limits the practical uses of super-hydrophobic surfaces. Accordingly, it is important to design a simpler method of fabricating a rough structure on the Ni-Co lamination surface.
Electrodeposited copper and copper based alloys are widely used in a wide range of applications. The formation of nanostructures on the surface of copper to generate ultra-hydrophobic influence has received much attention.
Chemical etching is one of the most used procedures to achieve said nanostructures. It has the advantage of being easy to use and inexpensive.
Considering these advantages, a copper coating is used to give Ni-Co an ultra-hydrophobic characteristic.
A copper coating was electrodeposited over a Ni-Co lamination in this study, forming a composite Ni-Co/Cu coating that demonstrated super-hydrophobic properties after being treated with oxidation solution and dodecanethiol modification.
The advantages of this technology are as follows: (1) the high water-repellent impact of Cu-coated surface development has been widely studied, and the procedure is reasonably easy; (2) the need for rigorous control over the development procedure of the nickel-cobalt coating is eliminated. Further, the surface hydrophilicity and corrosion resistance mechanism of the Ni-Co/Cu composite coating were examined.
The ultra-hydrophobic Ni-Co/Cu lamination was created on a carbon steel substrate using a two-step electroplating process and dodecanethiol modification to increase corrosion resistance.
The results demonstrated that this approach could increase the protective ability of Ni-Co coatings by preventing hostile media from coming into contact with the substrate, confirming the attractive practical potential of the technology in maritime environments. This technology offers a new way to improve the efficiency of Ni-Co coatings.
Lin, Z., Zhang, W., Zhang, W., Xu, L., Xue, Y. and Li, W. (2021) Fabrication of super-hydrophobic Ni–Co/Cu coating with heat resistance improved corrosion. Chemistry and physics of materials. Available at: https://www.sciencedirect.com/science/article/pii/S0254058421012864?via%3Dihub