Presently, numerous activities such as mining are carried out in seawater and ocean environment. However, the harsh climate and environmental conditions undermine the functionality of most of the specialized equipment used in various under seawater applications. To ensure efficient applications, this equipment must adapt to these conditions which have remained a great challenge. This has recently attracted significant attention of researchers who have identified surface protection through coating as a promising solution. Unfortunately, little is known about the mechanical and tribological properties of surface coatings under severe marine conditions.
Recent studies explored the various available ways of designing self-lubricating nanocomposite coatings. They allow altering of mechanical properties like hardness and toughness depending on the choice of the transition metal. Alternatively, vanadium carbide-based nanocomposites have been identified as a promising solution for use in a severe marine environment owing to their excellent performance.
Among the available methods for vanadium carbide coatings deposition, the multi-arc ion plating deposition method is widely used in industries. Generally, it offers a high ionization rate and fast deposition. Unfortunately, designing vanadium carbide coatings with excellent tribological and corrosive performance especially under marine environment is difficult due to the misunderstanding of the influence of phase components and microstructural characteristics.
To this note, Dr. Xin Jiang, Daqiang Zhao, Dr. Yongxin Wang and Liping Wang from Ningbo Institute of Materials Technology and Engineering in collaboration with Dr. Wenshan Duan from Northwest Normal University, College of Physics and Electronic Engineering investigated the influence of bias voltage on the microstructure, tribological and mechanical performances of vanadium carbide coatings. They further investigated their feasibility in seawater by examining their tribological and corrosion resistance behavior. Their work is currently published in the research journal, Ceramics International.
Briefly, the authors utilized multi-arc ion plating to deposit vanadium carbide nanocomposites coatings at substrate voltage ranging from -50 to -250V. Next, they investigated the factors affecting bias voltage as well as the effect of increasing the bias voltage on the mechanical properties of the vanadium carbide nanocomposite coating.
The authors observed that the carbon bonding was significantly affected by modulating bias voltage. For instance, depositing the coatings at a high bias voltage, the effects on hardening and toughening properties were exhibited through a combination of nanostructure manipulation and comprehensive stress. Furthermore, high bias voltage resulted in dense structure and smooth surface thus enhancing the anti-corrosion resistance. However, the nanocomposite coating deposited at a bias voltage of -250V exhibited excellent protective performance as compared to that deposited at a bias voltage of -50V.
In summary, the research team successfully implemented the protective performance of vanadium carbide nanocomposite coatings in severe seawater and environment. In general, they distinctly identified two approaches towards hard and tough nanocomposite coating including comprehensive stress and nanostructure manipulation which are ideal for enhancing the coating hardness and toughness. Altogether, the results showed the use of VC nanocomposite coating as a promising protective solution under seawater. It will thus enhance the lifespan and performance of various equipment used for different application under seawater.
Jiang, X., Zhao, D., Wang, Y., Duan, W., & Wang, L. (2019). Toward hard yet tough VC coating via modulating compressive stress and nanostructure to enhance its protective performance in seawater. Ceramics International, 45(1), 1049-1057.Go To Ceramics International