Preparation of stable and durable superhydrophobic surface on Zr-based bulk metallic glass

ZrO2 Superhydrophobic Coating with an Excellent Corrosion Resistance and Stable Degradation Performance on Zr-Based Bulk Metallic Glass

Photocatalysis is an energy-saving and high-efficiency green environmental technology. Because of its wide band gap and low light utilization, few studies have been conducted on ZrO2 used as a photocatalytic material. In this paper, a corrosion-resistant superhydrophobic ZrO2 coating was prepared on the surface of Zr-based bulk metallic glass by electrochemical etching. This coating not only showed a better corrosion resistance and easier collection, but also presented a stable degradation performance when combined with H2O2; these characteristics are necessary for photocatalysts to survive under harsh environments. This study provides a new direction for designing superhydrophobic surfaces on bulk metallic glass that possess a functional performance.

Stable superhydrophobic coating on Zr-based bulk metallic glass exhibiting excellent antibacterial property and cytocompatibility

A central challenge in the study of clinical medicine is to reduce the infection rate of implants without affecting cell adhesion and reproduction. For the first time, we prepared a robust and stable superhydrophobic Zn/pDop/SA coating on Zr₅₆Al₁₆Co₂₈ bulk metallic glass by electrodeposition that exhibits a maximum water contact angle of 158° and a sliding angle less than 1°. The growth of the coating micro-nano structure was controlled by changing the electrodeposition process parameters. The coating showed excellent antimicrobial adhesion properties in the environment to avoid bacteria adhesion and can transform from superhydrophobic to hydrophilic in body fluids to promote cell adhesion. The biodegradation of the Zn crystal structure was responsible for the hydrophobic transformation of the coating and the rough surface after biodegradation provided a point of adhesion for the cells. By designing a uniform crater structure on the substrate as an "armour" and co-depositing dopamine into the coating, the coating's wear resistance was greatly improved. The superhydrophobic coating can maintain stable superhydrophobicity in high temperature environment, air and UV irradiation. This study opens new horizons for the surface modification of bulk metallic glass and promotes its application in the medical field.

Recent Advances on the Abrasion Resistance Enhancements and Applications of Superhydrophobic Materials

Researches on superhydrophobicity have been overwhelming and have shown great advantages in various fields. However, the abrasion resistance of superhydrophobic structures was usually poor, and they were easily damaged by external force or harsh environment, which greatly limited the applications of superhydrophobic surfaces. Much attention has been paid to improving the abrasion resistance of superhydrophobic materials by researchers. In this review, aimed at the advances on improving the abrasion resistance of superhydrophobic surfaces, it was summarized and compared three enhancement strategies including the reasonably design of micro-nano structures, the adoption of adhesives, and the preparation of self-healing surface. Finally, the applications of typical superhydrophobic materials with abrasion resistance were reviewed in various fields. In order to broaden the application fields of superhydrophobic materials, the abarasion resistance should be further improved. Therefore, we proposed the ideas for the future development of superhydrophobic materials with higher abrasion resistance. We hope that this review will provide a new approach to the preparation and development of stable superhydrophobic surfaces with higher abrasion resistance.

Icing behavior of supercooled droplets on superhydrophobic polymercoatings between lotus effect and petal effect

This paper investigated anti-icing behavior and wettability of droplets on superhydrophobic polymercoatings between lotus effect and petal effect, which were prepared on surfaces of 2021 aluminum alloy with 1H, 1H, 2H, 2H-heptafluorodecyl (FAS-17). The prepared surfaces displayed excellent hydrophobicity with contact angles of 154.9° ± 1.5°and 139.8° ± 1.3°, while rolling angles are 4° ± 1.0° (lotus effect) and 30° ± 1.5° (petal effect). Thus, the present study focused on the different characterizations and the anti-icing potential of the superhydrophobic polymersurfaces were analyzed based on three parameters including the icing delay time, the crystallization temperature of water droplets, and contact time of impinging droplets on the cold superhydrophobic polymer coatings (−15 °C). Furthermore, the anti-icing of superhydrophobic coatings between lotus effect and petal effect with freezing time and crystallization temperature experimental phenomena were consistent with the thermodynamic analysis. It is also proved that the droplets have different bounce behavior on different polymercoating surfaces by droplet impact experiment. The study offers a comprehensive perspective on polymercoatings of different wetttablility for anti-icing behavior applications.

Achieving Superhydrophobicity of Zr-Based Metallic Glass Surfaces with Tunable Adhesion by Nanosecond Laser Ablation and Annealing

Tuning the surface wettability and adhesion of metallic glasses (MGs) is a promising approach to enrich their engineering applications. In this study, using nanosecond laser ablation in air, hierarchical micro/nanostructures were directly fabricated on a Zr-based MG surface. Following subsequent annealing, the surface exhibited superhydrophobicity (maximum contact angle: 166°, minimum sliding angle: 2°). Furthermore, the superhydrophobic surface could be tuned from low to high surface adhesion force by controlling the laser-ablated spot interval. By analyzing the laser-ablated structures and surface chemical compositions, the superhydrophobicity was related to the formation of hierarchical micro/nanostructures and the absorption of organic compounds with low surface free energy in air, and the change in surface adhesion force was attributed to the difference in surface roughness. The experimental results showed that the superhydrophobic surface with low adhesion force could be used in self-cleaning applications, while the superhydrophobic surfaces with different adhesion forces could be used in no-loss liquid transportation. This study provides an efficient and low-cost way to fabricate superhydrophobic MG surfaces with tunable adhesion, which will broaden the functional applications of MGs.

The Effect of Cu Additions on the Antibacterial Properties of Metallic Glassy Ni50TM50 (TM; Ti, Zr) Binary Systems

Antibacterial agents derived from classic organic compounds have been frequently employed for a number of years as a protective layer for biofilms. On the other hand, these agents often comprise dangerous components that, due to their interaction with toxic compounds, may be damaging to human beings. This hazard may be caused by the agents’ proximity to the toxic substances. Over the course of the past three decades, a variety of approaches, such as the utilization of a broad spectrum of metallic and oxide materials, have been the subject of research in order to develop a diverse selection of antibacterial coating layers that are acceptable. One of these approaches is the use of silver nanoparticles. It has been established that the cold spray technique, a solid-state method compatible with nanopowders, has shown higher performance and is the most effective strategy for coating materials. This has been proven via testing. It is possible to produce one-of-a-kind material coatings in ways that are not even remotely imaginable with any other thermal coating method, which is the primary reason for its prominence in contemporary production. The capacity to do so is what provides it with an advantage over its rivals in the market. This current study was conducted, in part, to investigate the effects of Cu-alloying elements on the antibacterial behavior of metallic glassy alloys on Ni50TM50 (TM; Ti, Zr) and Cu50TM40Ni10 (TM; Ti, Zr) systems prepared by the mechanical disordering technique, in conjunction with the cold spray method. These alloys were created by combining the mechanical disordering technique with the cold spray method. The arc melting process was employed to generate master alloys consisting of Ni50Ti50, Ni50Zr50, Cu50Ti40Ni10, and Cu50Zr40Ni10 for the purpose of this investigation. The master alloys were then used as feedstock materials for the creation of metallic glassy powders. Following the pulverization of the alloys of each system into a powdered form, the mixtures were charged through a high-energy ball milling operation for a duration of 50 h. Using the cold spray technique, the as-milled powders, which were metallic glasses, were applied singly in order to coat SUS304 sheets. The method was employed for this purpose. After the addition of Cu to the two binary Ni50TM50 (TM; Ti, Zr) alloys, the antibacterial properties of their corresponding metallic glassy phases were found to be significantly enhanced. This was shown by the fact that they were successful in preventing the development of biofilm by E. coli in contrast to the other systems that were evaluated.

Mechanical Alloying Integrated with Cold Spray Coating for Fabrication Cu50(Ti50-xNix), x; 10, 20, 30, and 40 at.% Antibiofilm Metallic Glass Coated/SUS304 Sheets

Antibacterial agents derived from conventional organic compounds have traditionally been employed as a biofilm protective coating for many years. These agents, on the other hand, often include toxic components that are potentially hazardous to humans. Multiple approaches have been investigated over the last two decades, including the use of various metallic and oxide materials, in order to produce a diverse variety of usable coating layers. When it comes to material coating approaches, the cold spray technique, which is a solid-state method that works well with nanopowders, has shown superior performance. Its capacity to produce unique material coating in ways that are not possible with other thermal methods is the primary reason for its importance in contemporary production. The present work has been addressed in part to explore the possibility of employing mechanically alloyed Cu50(Ti50-xNix)x; x = 10, 20, 30, and 40 at.% metallic glass powders, for producing an antibiofilm/SUS304 surface protective coating, using the cold spray approach. In this study, elemental Cu, Ti, and Ni powders were low-energy ball milled for 100 h to fabricate metallic glassy powders with different Ni contents. The as-prepared metallic glassy powders were utilized to coat SUS304 sheets, using the cold spraying process. With high nanohardness values, the as-fabricated coating material, in particular Cu50Ti20Ni30, demonstrated remarkable performance in comparison to other materials in its class. Furthermore, it displayed excellent wear resistance while maintaining a low coefficient of friction, with values ranging from 0.32 to 0.45 in the tested range. E. coli biofilms were formed on 20 mm2 SUS304 sheet coated coupons, which had been injected with 1.5 108 CFU mL-1 of the bacterium. With the use of nanocrystalline Cu-based powders, it is feasible to achieve considerable biofilm inhibition, which is a practical strategy for accomplishing the suppression of biofilm formation.