Search

Re-entrant structures have drawn increasing attention because of their hydrophobicity. However, it is very difficult to manufacture re-entrant structures at the micron scale on metal surfaces. In this study, we designed and manufactured novel hollow re-entrant structures employing laser ablation and electrodeposition technology. This designed hollow re-entrant structure on metal surfaces has been fabricated successfully, which has high processing efficiency and good repeatability. The morphology and size of the hollow re-entrant structures were characterized. We found that the hydrophobic performance of hollow re-entrant structures was improved after being in the atmosphere for 3 days. After electrodeposition, the static contact angle was 133°. However, after being placed in the atmosphere for 3 days, the static contact angle was 140.4°, which is 5.2% higher than that after electrochemical deposition. We explained the cause of this phenomenon. The change of element content on the surface of hollow re-entrant structures was used to indicate the formation of metal oxide. After being in the atmosphere for 3 days, oxygen content increased by 0.4%. The metal surfaces with hollow re-entrant structures have a broader application prospect.

Meniscus-confined electrodeposition (MCED), as one of multi-functional additive manufacturing methods for micro-sensor manufacturing and flexible electrical interconnection, has great potential in future miniaturized communication devices. At present, however, the understanding of the multi-physical field processes involved in this method, such as electrodeposition, fluid dynamics, mass and heat transfer, is limited, and the deposition forming process has not yet been well explained. In this work, the manufacturing process of metal microstructure used by MCED was studied, and the contour features of the microstructure were characterized. Simultaneously, based on the law of liquid phase mass transfer in microzone, the theoretical model of MCED process is established, the important role of Marangoni effect in evaporation process is revealed, and the effect of evaporation process on MCED is analyzed and discussed. Besides, the effect of evaporation process on the dynamic process of deposition is further proved by simulation analysis. The additive manufacturing equipment based on MCED was built to manufacture metal microstructure. Furthermore, the effects of evaporation on the morphology, roundness, vertical angle and chemical composition of deposited metal microstructure were analyzed experimentally. These results provide a promising platform for the direct fabrication of nanocircuit interconnections, micro sensors and micro antennas.

In this study, a simple method without any additional chemical modification is proposed to fabricate underoil superhydrophobic surfaces with micro- and nano-hierarchical structures using a nanosecond laser system. The fabricated surfaces exhibited extreme superhydrophobicity and underoil superhydrophobicity with high contact angles of 153.8 ± 1.5° and 161.3 ± 1.1°, respectively. The results show that even after 20 abrasion cycles, the fabricated surfaces retained water repellency and self-cleaning performance under oil, while the superhydrophobicity in air was not resistant to wear. In addition, the fabricated brass meshes can also be used to separate oil in an oil-water mixture based on the prewetting induced underoil superhydrophobicity after being damaged. The separation efficiency was as high as 97.8%, which made them more appropriate for the oil-water separation than those based on superhydrophobicity. The proposed fabrication method is suitable for large-scale and mass production and provides a new avenue and possibility for further development of robust functional interface materials.

Vibration-assisted cutting as one of specially typical precision non-conventional machining methods, recently, has aroused lots of scholars and science researchers interests, especially in hard and brittle material cutting with a significant challenge. The objective of present study develops a novel apparatus which combines mechanical and control design, a series of cutting experiments conducted on Al 7075 alloy that defined as one of high strength alloy materials appliance in lots of industries field to investigate the feasibility and reliability of the appliance. In present paper, a mechanical model of vibration- assisted cutting apparatus was designed and than evaluated by off-line test analysis. The novel apparatus can work at below 124 Hz with maximum stroke 27.285µm. Fuzzy PID was preliminary introduced into vibration-assisted cutting apparatus control strategy. Programs were established based on LabVIEW software and then downloaded into NI Compact 9033 controller in order to control vibration-assisted cutting apparatus. By compared with three strategies each other, the tracking error of fuzzy strategy increased 11.2 times that of fuzzy PID, at the same time, PID strategy oscillation amplitude increased 5.3 times that of fuzzy PID. A series of cutting experiments were conducted on the plane and freeform surface deforming. The validity and availability of vibration-assisted cutting apparatus were conducted in experiments.