Superhydrophobic Aluminum Alloy Surface Research Articles

Fabrication of superhydrophobic aluminum alloy surfaces by nickel and phosphorus chemical deposition

Fabrication of superhydrophobic aluminum alloy surfaces by nickel and phosphorus chemical deposition

Fabrication of wear-resistant and superhydrophobic aluminum alloy surface by laser-chemical hybrid methods

To achieve rapid, efficient, and low-cost preparation of large-scale stable aluminum alloy superhydrophobic surfaces, a new preparation method is proposed. The outer surface of the array micro-protrusions was coated with a layer of armor, which was the molten spatter produced during picosecond laser processing. The molten sputters and micro-protrusions combined to form micro–nano composite multi-layer structures. Through these special array micro–nano composite multi-layer structures and chemical modification, the wear-resistant and superhydrophobic properties of aluminum alloy surfaces were realized. According to test results, the array micro–nano composite structures prepared by picosecond laser and chemical modification had a water drop contact angle of 154.6° and a water drop rolling angle of 2°, exhibiting excellent superhydrophobic and anti-adhesion properties. Its self-cleaning, corrosion resistance and friction and wear behavior were systematically analyzed. The analysis results showed that the rolling droplets on the prepared surface could easily take away contaminants. The corrosion voltage and corrosion current density of the prepared superhydrophobic surface are significantly lower than that of the raw surface. In addition, a water drop contact angle of the aluminum alloy sample maintained at 145.1° after five wear tests, indicating the prepared surface after wear testing still had hydrophobic performance. The innovative method proposed in this study provides a simple and effective method for preparing large-scale wear-resistant superhydrophobic surface of aluminum alloy.

Experimental investigation on the impacting and freezing characteristics of water droplets on a PDMS-decorated superhydrophobic aluminum alloy surface

Due to the potential applications of superhydrophobic surfaces in water-repelling and anti-icing, it is of great interest to study the impacting and freezing processes of water droplets on superhydrophobic surfaces. In this study, the process of a water droplet impacting the PDMS-decorated superhydrophobic aluminum alloy (denoted as Al-PDMS) surface was studied, and the influences of a water droplet falling height and volume were systemically investigated with a high-speed camera. The results indicate that the impacting process can be categorized into four states, which are mainly affected by the dropping height. The bouncing processes of water droplets on horizontal superhydrophobic surfaces are studied by defining spreading factor α and rebounding factor β. Furthermore, the effect of the inclination angle φ of the superhydrophobic plate on the impacting behavior was investigated. The freezing processes of water droplets on superhydrophobic surfaces were also studied. The results showed that the delayed-icing time decreases with decreasing test plate temperature. Additionally, the volume and height of the frozen portion of the water droplets during freezing were investigated, and the movement characteristic of the freezing front was analyzed.

A Novel Simple Fabrication Method for Mechanically Robust Superhydrophobic 2024 Aluminum Alloy Surfaces

The mechanical durability of a superhydrophobic aluminum alloy surface is an important indicator of its practical use. Herein, we propose a strategy to prepare a superhydrophobic 2024 aluminum alloy surface with highly enhanced mechanical durability by using a two-step chemical etching method, using a NaOH solution as the etchant in step one and a Na2CO3 solution as the etchant in step two. Robust mechanical durability was studied by static contact angle tests before and after an abrasion test, potentiodynamic polarization measurements after an abrasion test and electrochemical impedance spectroscopy tests after an abrasion test. Furthermore, the mechanism for enhanced mechanical durability was investigated through scanning of electron microscopy images, energy-dispersive X-ray spectra, Fourier transform infrared spectra and X-ray photoelectron spectra. The testing results indicate that a hierarchical rough surface consisting of regular micro-scale dents and some nano-scale fibers in the micro-scale dents, obtained with the two-step chemical etching method, contributes to highly enhanced mechanical durability. Meanwhile, the as-prepared superhydrophobic 2024 aluminum alloy surface retained a silvery color instead of the black shown on the superhydrophobic 2024 aluminum alloy surface prepared by a conventional one-step chemical etching method using NaOH solution as the etchant.

A simple strategy towards construction of fluorine-free superhydrophobic aluminum alloy surfaces: self-cleaning, anti-corrosion and anti-frost

A simple strategy towards construction of fluorine-free superhydrophobic aluminum alloy surfaces: self-cleaning, anti-corrosion and anti-frost

Facile Fabrication of Durable Superhydrophobic Aluminum Alloy Surfaces by HS-WEDM and Chemical Modification

Durable superhydrophobic aluminum alloy surfaces were prepared through a facile method: combining high-speed wire electrical discharge machining and chemical modification. Three types of pulse width were selected to machine the aluminum alloy surfaces with different levels of surface roughness. The effect of immersion time in perfluorooctanoic acid on the wettability of the aluminum alloy surfaces was examined. The contact angle of the superhydrophobic aluminum alloy surfaces was [Formula: see text], and the sliding angle was [Formula: see text]. After sanding with coarse sandpaper, the aluminum alloy surfaces still exhibited superhydrophobicity with a stroke of 450[Formula: see text]cm, indicating good mechanical durability. The prepared superhydrophobic aluminum alloy surface heated for 2[Formula: see text]h within the 190–240∘C temperature range showed favorable thermal stability. In addition, the superhydrophobic aluminum alloy surface exhibited self-cleaning property. Therefore, the superhydrophobic aluminum alloy surface prepared by using the simple mass production method showed good mechanical stability, thermal stability, and self-cleaning property, as well as broad application potential.

Convenient and large-scale fabrication of cost-effective superhydrophobic aluminum alloy surface with excellent reparability.

Superhydrophobic surfaces are widely used in industry and daily life, yet their practical application is limited by their complicated preparation process, high cost, and poor repairability. We propose a low-cost, facile process for preparing superhydrophobic surfaces to address this limitation. Through a simple three-step spraying process, the rough structure was first constructed on the aluminum alloy, and upon modification by modifier, the superhydrophobic aluminum alloy surface was successfully prepared. The effect of the process parameters on wettability was experimentally studied. The results showed that this method can obtain superhydrophobic surfaces with a contact angle of 156.2° and contact angle hysteresis of 7.4° by simply adjusting the etching time and modifier concentration. In addition, it was found that the prepared surface can keep the superhydrophobic property unchanged at 180 °C, showing good thermal stability. When immersed in acetic acid and sodium hydroxide solution, the prepared surface can maintain its superhydrophobicity for about 2 days, showing good chemical stability. Besides, the surface has excellent repairability and can compensate for the short-life defects caused by poor friction resistance. This superhydrophobic surface with a simple preparation process, low cost, and excellent repairable characteristics also has excellent self-cleaning, antifogging, and antifrosting applications.

Fabrication of superhydrophobic micro-nanostructured aluminum alloy surface via a cost-effective processing using an ultra-low concentration of fluoroalkylsilane

Herein, superhydrophobic 4037 aluminum alloy surface with self-cleaning and anti-icing properties has been fabricated by a low-cost processing consisting of HCl/H2O2 treatment and modification of an ultra-low concentration of fluoroalkylsilane. Via a chemical etching, a coral-like hierarchical micro-nano structure has been formed on 4037 aluminum alloy substrate. Then, the wettability of etched surface treated with different levels of fluoroalkylsilane has been investigated. The results show that the etched surface after been modified with petroleum ether containing 20 mg fluoroalkylsilane can result in superhydrophobicity with a water contact angle of 160.8° and a sliding angle of 2.4°. Especially, effects of solvents on the wettability of fabricated surface have also been studied. It is found that alkane such as petroleum ether is suitably used as a solvent for fluoroalkylsilane due to a reduction on fluoroalkylsilane. In addition, obvious self-cleaning and anti-icing behaviors of the as-prepared superhydrophobic surface have been proved, which will extend the further application of aluminum alloy.

Improving the Laser Texture Strategy to Get Superhydrophobic Aluminum Alloy Surfaces

Changing the wetting properties of surfaces is attracting great interest in many fields, in particular to achieve a surface with a superhydrophobic behavior. Laser machining is an emerging technique to functionalize materials with high precision and flexibility without any chemical treatment. However, when it is necessary to treat large area surfaces laser-based methods are still too slow to be exploited in industrial productions. In this work, we show that by improving the laser texture strategy it is possible to reduce the laser processing time to produce superhydrophobic aluminum alloy surfaces. Three different surface texture geometries were micromachined; namely, square, circular and triangular lattice grooves. We found that if the spacing between the grooves is narrow, i.e., when the percentage of the textured surface is high, the volume of air trapped inside the micromachined structures plays an important role in the wetting behavior. Meanwhile, when the groove spacing approaches the droplet dimensions, the texture geometry has a preponderant influence. Based on these findings an appropriate choice of the laser texture strategy allowed the fabrication of superhydrophobic aluminum alloy surfaces with a 10% reduction of processing time.

Organic carbon dot coating for superhydrophobic aluminum alloy surfaces.

A novel fluorine-free and silicon-free superhydrophobic aluminum alloy (treated-Al) is fabricated by chemical etching using hydrochloric acid and hydrogen peroxide and modified with an organic carbon dot (OCD) coating. The water contact angle (CA) of the treated-Al surface increases with the OCD concentration. When etched aluminum (etched-Al) is modified with 0.5 mg/ml OCDs, a CA of 161.4° is achieved, which indicates good nonwettability. SEM results verify that porous microstructures with cavities are uniformly distributed on the surface of etched-Al, in contrast to the bare aluminum alloy, which forms a primary rough structure. After treatment with 0.5 mg/ml OCDs, a nanoparticle coating is dispersed on the rough structures of treated-Al-0.5, which can trap air and make a water droplet essentially rest on a layer of air. The treated-Al-0.5 material has good self-cleaning properties and can sweep away contaminants at both 20 and 0°C. The Ecorr and Icorr of treated-Al-0.5 are − 0.56 V and 2.82 × 10−6 A/cm2, respectively, which shows good anticorrosion performance.

Superhydrophobic surface on Al alloy with robust durability and excellent self-healing performance

In order to improve the durability and stability of artificial superhydrophobic materials, the superhydrophobic surface with excellent self-healing performance on aluminum alloy is prepared by an environment-friendly method with boiling water treatment and [email protected] nanocapsule deposition. The as-prepared superhydrophobic aluminum alloy surfaces exhibit outstanding durability and stability when subjected to a variety of circumstances. Meanwhile, the superhydrophobic aluminum alloy is endowed with excellent self-cleaning performance and corrosion resistance. The robust durability and stability as well as outstanding self-cleaning and corrosion resistance are quite favourable to the practical application. More importantly, the as-prepared superhydrophobic surfaces take on superior self-healing performance, and it provides a novel idea to improve the durability of superhydrophobic materials from another vision.

Robust anti-icing superhydrophobic aluminum alloy surfaces by grafting fluorocarbon molecular chains

Infusion of low surface tension liquids in nanostructured surfaces is currently used to promote an anti-icing response, although the long term stability of these systems is often jeopardized by losses of the infused liquid. In this work, we propose an alternative to the infusion procedure to induce a more effective and long lasting anti-icing capacity. The method consists of a combination of surface nanostructuration with the chemical grafting of fluorocarbon molecules. Al6061 substrates have been subjected to laser roughening and further modified with a nanostructured Al2O3 thin film to achieve a dual roughness and porous surface state. These surfaces have been subjected to a grafting treatment with perfluorooctyltriethoxysilane (PFOTES) vapor or, for comparative purposes, infused with a low surface tension liquid. A comparative analysis of the wetting, water condensation and anti-icing properties of these two systems showed an outstandingly better performance for the grafted surfaces with respect to the infused ones. Grafted surfaces were markedly superhydrophobic and required higher water vapor pressures to induce condensation. When looking for their anti-icing capacity, they presented quite long freezing delay times for supercooled water droplets (i.e. almost four hours) and exhibited a notably low ice accretion in a wind tunnel test. The high aging resistance and durability of these grafted surfaces and the reproducibility of the results obtained when subjected to successive ice accretion cycles show that molecular grafting is an efficient anti-icing methodology that, in aggressive media, may outperform the classical infusion procedures. The role of the fluorocarbon chains anchored on the surface in inducing an anti-icing functionality is discussed.

Superhydrophobic aluminum alloy surface with excellent universality, corrosion resistance, and antifouling performance prepared without prepolishing

AbstractIt is urgently necessary to seek more simple and effective methods to construct superhydrophobic metal surfaces to improve the corrosion resistance and antifouling performance. Herein, a facile method for fabricating superhydrophobic aluminum alloy surface is developed via boiling water treatment and stearic acid modification. It is noteworthy that no prepolishing on aluminum alloy is required and no caustic reagents and typical equipments are used during the preparation procedure. Therefore, the fabrication method is quite a simple and environment‐friendly technique. Both micro‐ and nano‐scaled binary structure forms at the resultant aluminum alloy surface while long alkyl chains are grafted onto the rough aluminum alloy surface chemically. Consequently, the resultant aluminum alloy exhibits outstanding superhydrophobicity. More importantly, the superhydrophobicity has excellent universality, diversity, stability, excellent corrosion resistance, and antifouling performance. The facile preparation, excellent superhydrophobic durability, and outstanding performance are quite in favor of the practical application.

Direct Femtosecond Laser Fabrication of Superhydrophobic Aluminum Alloy Surfaces with Anti-icing Properties

Ice formation is a serious issue in many fields, from energy to aerospace, compromising the devices’ efficiency and security. Superhydrophobicity has been demonstrated to be correlated to the anti-icing properties of surfaces. However, fabricating surfaces with robust water repellence properties also at subzero temperature is still a great challenge. In this work, femtosecond laser (fs-laser) texturing is exploited to produce superhydrophobic surfaces with anti-icing properties on Al2024, an aluminum alloy of great interest in cold environments, in particular for aircraft production. Our textured substrates present self-cleaning properties and robust water repellency at subzero temperatures. Moreover, outstanding anti-icing properties are achieved on the textured surfaces at −20 °C, with water droplets bouncing off the surface before freezing.

Robust superhydrophobic aluminum alloy surfaces with anti-icing ability, thermostability, and mechanical durability

In this study, we develop an efficient approach to fabricate superhydrophobic aluminum alloy samples. The superhydrophobic aluminum alloy sample is prepared by combining high-speed wire electrical discharge machining, a short-time chemical etching method, with a modification treatment. The prepared superhydrophobic aluminum sample possesses a contact angle of 158.6 ± 1.3° and a sliding angle of below 1°. The introduction of chemical etching can shorten the preparation time from 20 to 8 h. The prepared superhydrophobic aluminum alloy sample is durable enough to endure the harsh conditions to which some aluminum alloy parts are subjected. Its excellent anti-icing ability is confirmed by the freezing delay test and low-temperature durability test under overcooled conditions. In addition, the prepared superhydrophobic aluminum alloy sample shows superior thermostability and high-temperature durability in the range of 180∼240 °C. Moreover, the prepared superhydrophobic aluminum alloy sample exhibits outstanding mechanical durability that can endure abrasion by 1000-grit sandpaper at 20 kPa for 260 cm. It also can withstand 11 vertical impacts by 200 g weight dropped from 12 cm with the weight falling on the sample at a rate of ∼15.50 cm/s. The introduction of the chemical etching greatly shortens the preparation time and the as-prepared superhydrophobic aluminum alloy sample exhibited excellent durability, which may widen the application range of superhydrophobic aluminum alloys.

레이저 가공과 열처리로 제작된 초소수성 알루미늄 합금 표면의 부식 저항 연구

레이저 가공과 열처리로 제작된 초소수성 알루미늄 합금 표면의 부식 저항 연구

Fabrication of Self-Cleaning Superhydrophobic Surfaces with Improved Corrosion Resistance on 6061 Aluminum Alloys.

Aluminum alloys are widely used, but they are prone to contamination or damage under harsh working environments. In this paper, a self-cleaning superhydrophobic aluminum alloy surface with good corrosion resistance was successfully fabricated via the combination of sand peening and electrochemical oxidation, and it was subsequently covered with a fluoroalkylsilane (FAS) film. The surface morphology, surface wettability, and corrosion resistance were investigated using a scanning electron microscope (SEM), an optical contact angle measurement, and an electrochemical workstation. The results show that binary rough structures and an FAS film with a low surface energy on the Al alloy surfaces confer good superhydrophobicity with a water contact angle of 167.5 ± 1.1° and a sliding angle of 2.5 ± 0.7°. Meanwhile, the potentiodynamic polarization curve shows that the corrosion potential has a positively shifted trend, and the corrosion current density decreases by three orders of magnitude compared with that of the original aluminum alloy sample. In addition, the chemical stability of the as-prepared superhydrophobic surface was evaluated by dripping test using solutions with different pH values for different immersion time. It indicates that the superhydrophobic surface could provide long-term corrosion protection for aluminum alloys. Consequently, the as-prepared superhydrophobic surface has excellent contamination resistance and self-cleaning efficacy, which are important for practical applications.

Oil-Repellent and Corrosion Resistance Properties of Superhydrophobic and Superoleophobic Aluminum Alloy Surfaces Based on Nanosecond Laser-Textured Treatment

As two typical special wettability materials, superhydrophobic and superoleophobic surfaces are the most widely studied interfaces because of their excellent water-or oil-repellent ability. However, how to use a simple strategy to obtain those surfaces is still a huge challenge. On the other hand, corrosion tend to occur while using metallic materials, resulting in poor performance of metallic equipment and even serious safety hazards. In this work, a one-step strategy of nanosecond laser ablation was presented to construct the microstructures acquired by superhydrophobic and superoleophobic aluminum alloy surfaces. The superhydrophobic and superoleophobic properties of microstructured surfaces were obtained via high temperature and fluorosilane treatments on laser-processed surfaces, respectively, and the oil-repellent and corrosion resistance properties of both substrates were studied. The potentiodynamic polarization test shows that the superoleophobic surface had a better corrosion resistance than the superhydrophobic surface, which will provide an effective protection for the bare aluminum alloy. Meanwhile, the superoleophobic surface had good chemical stability. It is believed that the nanosecond laser technology can offer an effective strategy for constructing the microstructures acquired by large-area superhydrophobic and superoleophobic surfaces on aluminum alloy materials.

A Laser Scanning Method to Control the Location, Shape, Contact Angle and Sliding of Water Droplet on Superhydrophobic Surface

A simple and novel approach is proposed to control location, shape, contact angle, and sliding of droplet on superhydrophobic aluminum alloy surfaces scanned by laser. By firstly etched suitably, followed by coating with stearic acid, aluminum alloy surface is possible to exhibit the property of superhydrophobic behavior. Irradiating such surface with specific hydrophilic patterns, by a relatively high power and precisely controlled laser, allows fixing the location and shape of water droplets. Suitably altering scanning time and power of the laser beam, the fabricated surface facilitates the control of the contact angle of droplet. Properly railing hydrophilic lines/curves on such superhydrophobic surface facilitates constraining droplet to slide and water to flow in certain controllable orientations. Furthermore, relevant likely mechanisms involved in controlling the location, shape, contact angle, and sliding of water droplet on hydrophobic/hydrophilic surface have also been elucidated systematically on the basis of analyzation of electrical scanning images.

Droplet Impact on the Super-Hydrophobic Surface with Micro-Pillar Arrays Fabricated by Hybrid Laser Ablation and Silanization Process.

A super-hydrophobic aluminum alloy surface with decorated pillar arrays was obtained by hybrid laser ablation and further silanization process. The as-prepared surface showed a high apparent contact angle of 158.2 ± 2.0° and low sliding angle of 3 ± 1°. Surface morphologies and surface chemistry were explored to obtain insights into the generation process of super-hydrophobicity. The main objective of this current work is to investigate the maximum spreading factor of water droplets impacting on the pillar-patterned super-hydrophobic surface based on the energy conservation concept. Although many previous studies have investigated the droplet impacting behavior on flat solid surfaces, the empirical models were proposed based on a few parameters including the Reynolds number (Re), Weber number (We), as well as the Ohnesorge number (Oh). This resulted in limitations for the super-hydrophobic surfaces due to the ignorance of the geometrical parameters of the pillars and viscous energy dissipation for liquid flow within the pillar arrays. In this paper, the maximum spreading factor was deduced from the perspective of energy balance, and the predicted results were in good agreement with our experimental results with a mean error of 4.99% and standard deviation of 0.10.