Aluminum Surface Research Articles

Superhydrophobic Coatings Based on PMMA-Siloxane-Silica and Modified Silica Nanoparticles Deposited on AA2024-T3

The study aimed to develop a superhydrophobic coating on the aluminium alloy 2024-T3 surface. The desired surface roughness and low surface energy were achieved with SiO2 nanoparticles, synthesised via the Stöber method and modified with alkyl silane (AS) or perfluoroalkyl silane (FAS). To enhance particle adhesion to the alloy substrate, nanoparticles were incorporated into a hybrid sol–gel coating composed of tetraethyl orthosilicate, methyl methacrylate, and 3-methacryloxypropyl trimethoxysilane. The coated substrates were characterised using field emission scanning and transmission electron microscopy with energy-dispersive spectroscopy for surface topography, nanoparticle size distribution, composition, and coating thickness. The corrosion resistance of the coatings on AA2024-T3 was evaluated in a 0.1 M NaCl solution using electrochemical impedance spectroscopy. The synthesised SiO2 nanoparticles had an average size between 25 and 35 nm. The water contact angles on coated aluminium surfaces reached 135° for SiO2 + AS and 151° for SiO2 + FAS. SiO2 + FAS, indicating superhydrophobic properties, showed the most uniform surface with the most consistent size distribution of the SiO2 nanoparticles. Incorporation of nanoparticles into the hybrid sol–gel coating further improved particle adhesion. The ~2 µm-thick coating also demonstrated efficient barrier properties, significantly enhancing corrosion resistance for over two months under the test conditions.

A Streamlined Approach to Anticounterfeiting Technologies: Patterned AAO Membranes Based on Photonic Crystal Effects with Tunable Color Shifts and pH Responsiveness.

Anticounterfeiting technologies have become increasingly crucial due to the growing issue of counterfeit goods, particularly in high-value industries. Traditional methods such as barcodes and holograms are prone to replication, prompting the need for advanced, cost-effective, and efficient solutions. In this work, a practical application of anodic aluminum oxide (AAO) membranes are presented for anticounterfeiting, which addresses the challenges of high production costs and complex fabrication processes. Unlike previous approaches requiring metal coatings for color generation, this method uses commercial aluminum foils to produce colorful AAO membranes without metal layers. Elemental mapping suggests that impurities on the aluminum surface contribute to enhanced reflectivity, aiding photonic crystal formation. A two-step anodization process that creates patterned AAO membranes is further introduced, with the pattern clarity controlled by anodization time. Additionally, a pH-responsive film composed of 2-anilino-6-dibutylaminofluoran (ODB-2) and thermoplastic polyurethane (TPU) is integrated, enabling dynamic color changes under varying pH conditions, further enhancing the anticounterfeiting functionality. This streamlined approach provides a scalable and cost-effective solution for developing versatile AAO membranes for industrial anticounterfeiting applications.

Harnessing 3D Porous Cobalt Oxide Nanoflakes Grown on Metal for Exceptional Adhesion between Aluminum Surfaces and the Epoxy Matrix

The developments in the automotive and aerospace sectors require alternative structures to metals for diverse applications; therefore, lightweight polymer–metal hybrid composites with outstanding mechanical characteristics are synthesized. Herein, the modern nanoperfusion technology, which involves the in situ growth of 3D porous cobalt oxide nanoflakes (Co3O4 NFs) on the porous aluminum surface, is used. A rough surface with corresponding surface porosities of 21, 48.1, and 49.8% can be produced by anodization of aluminum at 8, 10, and 12 V, respectively. The samples anodized at 10 V are selected as a structure for the growth of 3D Co3O4 NFs at different hydrothermal temperatures (90, 120, and 160 °C). The bond strength and modulus of the toughness of the sample combining aluminum and 3D Co3O4 NF growth at 120 °C exhibit a substantial bonding strength, reaching a value of 14.27 MPa and 3.56 kJ m−3, respectively. The porous nature of the manufactured cobalt oxide nanoflakes allows the epoxy to penetrate, which enhances the bonding strength and thus improves the mechanical properties of the manufactured joints.

Plasma Treatment of Metal Surfaces for Enhanced Bonding Strength of Metal–Polymer Hybrid Structures

The adhesion between metals and polymers plays a pivotal role in numerous industrial applications, especially within the automotive and aerospace sectors, where there is a growing demand for materials that are both lightweight and durable. This study introduces an innovative technique to improve the adhesion between a metal and a polymer in hybrid structures through the synergistic use of anodization and plasma treatment. By forming a nanoporous oxide layer on aluminum surfaces, anodization enhances the interface for polymer binding. Plasma treatment further augments the surface properties by increasing the concentration of functional groups, thus allowing better polymer infiltration during the 3D printing process. Comprehensive analyses, including X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, and contact angle measurements confirm the substantial enhancement in the bonding strength achieved through this method. Additionally, cross-sectional analysis via focused ion-beam etching provides a detailed view of polymer integration into the treated layers. The findings suggest significant potential for these surface modification strategies to advance the development of lightweight, robust composites suitable for use in sectors such as automotive, aerospace, and consumer electronics.

Obtaining Damage Parameters for Out‐of‐Plane Adhesive Failure in Epoxy–Aluminum Interface

ABSTRACTThis study investigates the out‐of‐plane adhesive failure mechanisms at the interface between Araldite 2011 epoxy adhesive and aluminum surfaces. Pull‐off tests were performed on aluminum substrates, which were prepared using various grades of sandpaper to evaluate the effect of surface roughness on the adhesive strength. The results showed that aluminum surfaces treated with P150 sandpaper provided better adhesion compared to other surface preparations. However, scanning electron microscopy (SEM) analysis and visual inspections of the fracture surfaces confirmed that interfacial adhesive failure was the dominant failure mode. A modified triangular traction–separation (TS) damage model was developed to characterize the adhesive/aluminum interface, taking into account the influence of surface roughness. This model was constructed using load–displacement data from the pull‐off tests. Additionally, a 2D axisymmetric finite‐element model was created to simulate the mechanical behavior of the system, and the TS model was validated against experimental results. The numerical analysis revealed that the interfacial region experiencing adhesive failure played a critical role in the load–displacement response of the pull‐off specimens.

Bio-based waterborne polyurethanes from castor oil, sorbitan monooleate and sodium lignosulfonate with ultraviolet resistance, photothermal effect, corrosion protection and degradation properties

The advancement of bio-based materials derived from renewable resources provides a pivotal strategic approach to address the problems of environmental pollution and scarce fossil resources. In this study, a series of bio-based waterborne polyurethanes (WPUs) with enhanced UV resistance, photothermal effect and corrosion resistance were prepared by using sorbitan monooleate (SP) and castor oil (CO) as vegetable polyols together with the introduction of sodium lignosulfonate modified of diethanolamine (DML). The WPU coatings of only 100 μm thickness, exhibited UV blocking rate > 99 % between 200 and 320 nm. Furthermore, the synthesized WPUs had superior adhesion to aluminum, tinplate, and PVC surface, with adhesion to tinplate of up to 5B and hardness of up to 3H. Additionally, the WPU coatings showed favorable photothermal effect when exposed to 1.05 W/cm2 of near-infrared light irradiation, with maximum surface temperature of 93 °C. The WPU coatings demonstrated noteworthy corrosion protection, with high corrosion protection efficiency of 96.97 % on tinplate. This study presents a new strategy for the synthesis of bio-based WPUs with excellent ultraviolet resistance, favorable photothermal effect, corrosion protection, and degradability. The unique properties lay the foundation for the applications of bio-based WPUs in the field of industrial coatings.

Improving aluminum surface defect super-resolution with diffusion models and skip connections

Improving aluminum surface defect super-resolution with diffusion models and skip connections

Euphorbia neriifolia extracts as green corrosion inhibitors for aluminium in hydrochloric and nitric acid media

Among the new, significant approaches for preventing corrosion in contemporary culture is using green corrosion inhibitors, which lower corrosion rates to an acceptable level with minimal negative effects on the environment. This area of investigation has witnessed substantial advancements from the environmental sustainability perspective. This study investigates the corrosion inhibition potential of Euphorbia neriifolia extracts on aluminium in various concentrations of hydrochloric acid (HCl) and nitric acid (HNO₃) using weight loss, thermometric methods, and Field Emission Scanning Electron Microscopy (FESEM) analysis. The weight loss method revealed maximum inhibition efficiencies of 94.92% and 92.62% for the stem extract at a concentration of 0.7% in 1 M HCl and 1 M HNO₃, respectively. The Langmuir adsorption isotherm indicated a strong linear relationship between surface coverage and inhibitor concentration, suggesting favorable monolayer adsorption on the aluminum surface. Thermometric analysis confirmed the efficacy of the extracts, with a significant reduction in corrosion rates from 157.89 mm/yr in the absence of inhibitors to 0.0099 mm/yr with the optimal concentration of stem extract in 1 M HCl. FESEM images illustrated a marked difference in surface morphology, revealing a smooth, intact surface in the presence of the extracts compared to rough, pitted surfaces in the control samples exposed solely to acidic environments. This work demonstrates the high efficacy and potential modes of action through adsorption of Euphorbia neriifolia extracts, drawing attention to their intriguing use as environmentally benign corrosion inhibitors. The results offer a new, biodegradable substitute for traditional synthetic inhibitors and add to the expanding corpus of research supporting sustainable corrosion management techniques.Graphical

Addressing of Aluminum Anode Based Battery Challenges: Electrochemical Effect of Zn-Mn Electrodeposition

Aluminum (Al) has emerged to become one of the potential anode materials candidates in metal-based batteries due to its abundant resource, inexpensive cost, good safeness and high theoretical energy density. However, thoughtful challenges have been barrier towards huge progress, including easy aluminum hydroxide formation, low practical voltage, and high corrosion rate. To approach those problems, this article proposes to enhance the electrochemical performance of anode side through electrodeposition of Zn-Mn on aluminum surface. The deposition of Zn-Mn consists of citrate and ethylenediaminetetraacetic acid (EDTA) as complexing agent to control the process rate. The effect of various deposition time, 0, 10, and 30 minutes, will be investigated by linear polarization, linear sweep voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy measurements. The electrochemical measurement exhibits the deposition effect, minimized the impedance of Al surface and improved the electrochemical reactions. Moreover, the appearance of Zn-Mn layer has prolonged the discharge performance with battery analyzer measurements. Therefore, energy density increased from 1270.52 to 3327.68 mWh g-1Al and the specific capacity enhances from 2779.908 to 7291.651 mAh g-1. All the measurements applied 3.5% sodium chloride (NaCl). These results pose the electrical performance enhancement from the anode side, but the development of other sides is also necessary.

Investigation of the conditions (nature) of pentacoordinated aluminum oxide formation

Aluminum oxide is widely used as a catalyst carrier, including in internal combustion engine systems, where operating temperatures exceed 1000 °C. As such, aluminum oxide must exhibit enhanced thermal stability. This property is linked to the presence of pentacoordinated centers on the surface of the γ-phase of Al2O3. This paper examines the effect of the pH during aluminum hydroxide precipitation on the formation of pentacoordinated centers on the surface of aluminum oxide. The samples of aluminum hydroxide were synthesized via controlled double-jet precipitation, followed by thermal decomposition into oxides. Precipitation was carried out at constant pH levels, and for comparison, parallel samples were synthesized at pH values of 5, 6, 7, 8, and 9. The precursors for precipitation were a 1 M aluminum nitrate solution (Al3+) and a 10 wt. % ammonia solution (NH4OH). The solutions were introduced into the reactor in a dropwise mode with continuous stirring. The resulting aluminum oxide samples were analyzed using X-ray diffraction and nuclear magnetic resonance techniques. The data show a direct correlation between the pH of aluminum hydroxide precipitation and the presence of pentacoordinated centers on the aluminum oxide surface: the higher the pH, the lower the content of pentacoordinated atoms. Additionally, a relationship was observed between the pH value and the size of the coherent scattering region, with an increase in coherent scattering observed at higher pH levels.

Novel variant transformer-based method for aluminum profile surface defect detection

Abstract The detection of surface defects on metal plays a pivotal role in the evaluation of product quality for aluminum profiles. So far, the most prevalent approach for detecting metal surface defects is still through the utilization of traditional conventional neural networks (CNNs). However, transformer-based methods have made notable improvements in computer vision in recent years, exhibiting superiority over traditional CNNs in the majority of tasks. In regard to aluminum surface defect image characteristics, such as intricate textures, few defect samples, and large-scale differences in various defects, traditional CNNs have difficulty further improving performance. This paper proposes a novel method based on a variant transformer for surface defect detection of aluminum profiles, which combines a traditional CNN and a transformer architecture with a deformable attention module (DAM). The DAM better focuses on part of critical sampling points around the reference point, which alleviates the unacceptable complexity in high-resolution feature maps and enhances the recognition effect of small target defects. The image stitching method proposed uses defect-free samples to generate new samples, which partially mitigates the issue of class imbalance. Moreover, we carried out supplementary experiments to confirm the effectiveness of transfer learning in training small-scale datasets. Compared with the baseline, the mean average precision (mAP) was improved by 3.32%. Extensive experimental results demonstrate the efficacy of our method in accurately detecting surface defects of aluminum profiles and significantly improving the detection of small target defects.

Decreased Secondary Electron Emission from Aluminum Surface by a Fluorocarbon-Titanium Composite Film.

Multipactor, a vacuum discharge under microwave conditions triggered by secondary electron emission (SEE), plays a critical role in managing the power level of microwave devices. In this study, we developed a fluorocarbon-titanium composite film on aluminum by cosputtering polytetrafluoroethylene (PTFE) and titanium via a controlled temperature and sputtering power ratio (RF power for PTFE to DC power for Ti) to suppress the SEE of Al. The evolution of microtopography and chemical composition of the composite film was evaluated. An increasing power ratio varying from 0.5 to 3.0 is found to change the film surface from scattered island-like bumps to a prominent peak-valley pattern and eventually to a smooth surface with few flat swellings. Elemental analysis revealed that the fluorine-to-carbon (F/C) mole ratio in samples was more significantly influenced by the sputtering power ratio than by the substrate temperature. The SEE yield indicates that the peak-valley pattern prepared by a power ratio of 2 leads to the maximum of the SEE yield curve reducing steeply from 2.99 to 1.23, which is attributed not only to the roughed pattern but also to the high F/C mole ratio owing to the higher capacity of electron trapping by the fluorine atoms.

Mask-Enabled Topography Contrast on Aluminum Surfaces.

Patterned solid surfaces with wettability contrast can enhance liquid transport for applications such as electronics thermal management, self-cleaning, and anti-icing. However, prior work has not explored easy and scalable blade-cut masking to impart topography patterned wettability contrast on aluminum (Al), even though Al surfaces are widely used for thermal applications. Here, we demonstrate mask-enabled topography contrast patterning and quantify the resulting accuracy of the topographic pattern resolution, spatial variations in surface roughness, wettability, drop size distribution during dropwise condensation, and thermal emissivity of patterned Al surfaces. The method uses blade-cut vinyl mask templates and a commercially available lacquer resin that serves as a polymer resist against etching. Programmable mask templates enable complex patterning of wettability and emissivity contrast with feature sizes down to ∼1.5 mm. As-fabricated patterned samples show a water contact angle (θ) contrast from <5° to 80° between etched and smooth zones, while patterned samples that are further coated with a hydrophobic promoter show θ contrast between 150° and 120° on etched and smooth zones, respectively. In addition to measuring this wettability contrast via contact angle goniometry, we use condensation visualization experiments to study the spatially controlled condensate morphologies and drop size distributions. These condensation studies demonstrate enhanced droplet shedding on the superhydrophobic regions of striped patterned surfaces compared to homogeneous superhydrophobic surfaces. Motivated by the role of thermal radiation in many phase change processes, we use infrared thermography to map topography-mediated thermal emissivity (ε) contrast between etched (ε ≈ 0.65) and smooth (ε ≈ 0.26) regions. Thus, our study provides a route for researchers to readily create complex and scalable topography-patterned Al surfaces for potential applications in vapor chamber thermal rectification, radiative cooling condensation heat transfer, and high-temperature Leidenfrost or film boiling processes.

The effect of anodization and subsequent treatments on corrosion resistance of aluminium

Aluminium samples were chemically prepared by following operations: degreasing, etching I, etching II, and brightening), prior to anodizing in sulfuric acid. Aluminium surface area was 0.2 dm2. The composition of used aluminium samples was determined by the energy dispersive X-ray spectroscopy. Chemically prepared aluminium samples were electrochemically anodized for 45 minutes in a solution of 190 gdm-3 H2SO4 at room temperature, at a current density of 1.7 Adm-2. In the anodizing process, the aluminium sample served as the anode, with lead cathodes. After anodizing, the aluminium samples underwent a colouring process in five pairs of solutions (systems), where each system consisted of two solutions of inorganic salts RxA + RxB (x = 1-5, numbers of solutions). Colouring of the anodized aluminium was carried out at room temperature by immersing the samples in each solution for 7 minutes (e.g., R1A + R1B, τ = 7 min + 7 min). Each used colouring system provides a different colour: green-yellow, brown, light-grey, blue, and orange-gold. After colouring, the samples were treated in a special solution to improve corrosion resistance and silication, resulting in a change in the obtained colour shade. All obtained colours were stable with very nice appearance, allowing such coloured aluminium to be used for decorative purposes. The corrosion resistance of the coloured anodized aluminium samples was investigated by determining the corrosion potential, corrosion current and polarization resistance using potentiodynamic polarization method, as well as by electrochemical impedance spectroscopy. A common feature of all tested samples is a significant improvement in the corrosion resistance of the anodized aluminium after colouring and subsequent treatment in the corrosion resistance improvement solution, particularly after the additional silane treatment.

Investigation on the Properties of Methyl 4-(((1-H benzo[d]imidazol-2-yl) methyl)thio)methyl)Benzoate on Aluminum Corrosion in Acidic Environment

Organic inhibitors are crucial for preserving metals from corrosion in acidic environments. In this regard, the methyl 4-(((1-H benzo[d]imidazol-2-yl)methyl)thio)methyl)benzoate (M-41HBI-2MTMB) was synthesized and investigated as an eco-friendly inhibitor for aluminum in a molar nitric acid solution (1 M HNO&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;). The gravimetric technique was used to study the inhibitory properties of the molecule, and the density functional theory (DFT) was conducted to elucidate the corrosion inhibition mechanism. The experimental data indicated that M-41HBI-2MTMB reduced the corrosion of the metal with a significant inhibition efficiency. The corrosion inhibition increased with an increase in the concentration of the molecule, reaching an efficiency of 98.5% at a concentration of 5.10&amp;lt;sup&amp;gt;-3&amp;lt;/sup&amp;gt; M, and a temperature of 298 K. Adsorption isotherms and thermodynamic parameters were studied to elucidate the interactions between M-41HBI-2MTMB and the metal surface. The inhibitor adsorbed spontaneously onto the aluminum surface following the Villamil model (modified Langmuir isotherm). Additionally, the Gibbs free energy less than - 40 kJ.mol&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; and the negative value of the enthalpy of adsorption suggested mixed-type adsorption with a predominance of physical interactions. The theoretical findings of DFT calculations revealed a positive fraction of electrons transferred (&amp;lt;i&amp;gt;ΔN = 0.247 eV&amp;lt;/i&amp;gt;), a high value of the electrophilicity index (&amp;lt;i&amp;gt;ω = 3.807 eV&amp;lt;/i&amp;gt;) as well as a low energy gap (&amp;lt;i&amp;gt;ΔE = 4.478 eV&amp;lt;/i&amp;gt;) showing favorable interactions of M-41HBI-2MTMB with its environment. The active sites of the molecule were highlighted at the level of carbon atoms, and a corrosion inhibition mechanism was proposed.

Effect of Cu addition on microstructure, wear, and corrosion resistance of AlCoCrFeNiSi0.5Cux (x = 0.01, 0.05, 0.1) high-entropy alloys

The influence of copper addition on the structure and selected properties of AlCoCrFeNiSi0.5Cux high-entropy alloys is described. Slowly cooled ingots were prepared by induction melting, and the samples in the form of plates were obtained by pressure casting. The conducted structural studies confirmed the presence of BCC/B2 phase. Microsegregation in the ingots was associated with the formation of intermetallic Cr3Si and Fe5Si3 phases. An increase in the cooling rate stopped segregation by reducing the mobility of Cr and Si. The hyperfine magnetic field distributions indicated the formation of the BCC Fe(Co,Ni,Si,Cr) solid solution for alloys in the form of plates. The lowest corrosion-current density (0.04 μA/cm2) in 3.5%-NaCl solution was obtained for the plate with the lowest copper content. The dominated aluminum surface states for the post-corrosive plates highlighted the binding energies of Al2O3. A tendency of reduced coercivity with increased copper content was observed. The positive effect of copper addition on wear resistance was confirmed for the AlCoCrFeNiSi0.5Cu0.1 alloy.

Искажение геометрии, окисление кромки, структурные изменения и морфология поверхности реза листового проката толщиной 100 мм из алюминиевых, медных и титановых сплавов при плазменной резке на токе обратной полярности

The introduction describes the feasibility of using reverse polarity plasma cutting to produce large-sized non-ferrous metal blanks up to 100 mm thick. Data on the use of plasma cutting with direct and reverse polarity currents for thick sheet metal and the main technological problems associated with its implementation are presented. The purpose of the work is to study the organization of the structure and properties of the near-surface zone, changes in the chemical and phase composition when cutting aluminum, copper and titanium alloys. The research methods are optical and scanning electron microscopy, microhardness measurement, X-ray diffraction and energy-dispersive analysis. Plasma cutting was carried out using air as a plasma-forming and shielding gas, simultaneously with water injection into the discharge chamber and the formation of a “water fog” around the plasma column. Results and discussion. It is shown that both the arc stability and the shape of the plasma column are of great importance in reverse polarity plasma cutting of rolled sheets. The distortion of the cutting geometry during normal operation is greatest in the central part, and with insufficient heat input it shifts to the lower part and increases significantly. The operation of the plasma torch in air does not lead to significant changes in the composition of the cutting surface of aluminum and copper alloys. A decrease in the magnesium content near the edge is typical for the aluminum alloy in the surface layers. Cutting of the titanium alloy is accompanied by intense oxidation of the surface, especially in areas of difficult metal displacement from the cutting cavity. The formation of titanium oxides, mainly rutile Ti2O, sharply increases the microhardness values in the surface layers, which negatively affects the machinability of the cutting edge and requires shot blasting to remove the oxide layer. The conclusion describes the main patterns of implementing reverse polarity plasma cutting of sheet metal from aluminum, copper and titanium alloys with a thickness of 100 mm.

A quantitative, label-free visual interference colour assay platform for protein targeting and binding assays

The vast array of immunoassay technologies used to assess protein interactions is costly or platform-specific. We present a label-free visual interference colour assay (VICA) that quantifies peptide and protein interactions by creating an iridescent surface allowing direct visualisation without spectrophotometric optics or microfluidics. A nanoporous aluminium oxide surface is tuned to match the refractive indices of the overlying protein layers to generate visual interference colours. To functionalise the surface, we created an affinity-capture system using a protein A-carboxyglutamic (GLA) construct that orients antibodies to enhance the signal. Using off-the-shelf antibodies, the platform can isolate analytes in buffer, whole blood, or serum. This surface generates a discernible colour change at concentrations as low as 50 femtomoles/mm2 and can monitor oligomer formation in sequential steps on the same slide. VICA provides comparable kinetic parameters to biolayer interferometry and traditional immunoassays while also allowing characterisation of proteins in large macromolecular complexes.

Aluminum Product Surface Defect Detection Method Based on Improved CenterNet

In order to realize real‐time detection of aluminum defects during aluminum production, the target detection algorithm needs to be able to run on locally deployed hardware. Convolutional neural networks can effectively extract representative features from high‐dimensional data such as images and videos, and capture spatial information in the data, making it easier to locate aluminum defects. Moreover, running CNN model inference on local hardware has high real‐time performance. Due to the advantages of convolutional neural network in anomaly detection, an improved CenterNet aluminum surface defect detection method was proposed. The algorithm combines common convolution and depthwise separable convolution to design a lightweight convolution module. Then, the Convolutional Block Attention Module is added to the feature extraction network to make the network better capture the rich input feature information of the image. Ultimately, the α‐DIoU loss function is implemented to enhance the precision of bounding box predictions. The experimental findings demonstrate that the proposed algorithm achieves an average detection accuracy (mAP) of 86.02%, which is 5.95% higher than the average detection accuracy of the traditional algorithm, and has a good detection effect on aluminum surface defects. Furthermore, there is an 11.9% reduction in model parameters and a 15.2% decrease in floating‐point computations, which helps to promote the deployment of embedded device platforms. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

Electrodeposition of Sacrificial Layer, Al2O3/ZnTPP film, onto NiTi Orthodontic Wire: Surface Characterizations and Electrochemical Investigations

Background: NiTi (nickel-titanium) alloy wires are widely used in orthodontics due to their unique properties, such as shape memory and superelasticity. However, these wires can be susceptible to corrosion in the oral environment, which can compromise their mechanical performance and longevity. Zinc tetraphenyl porphyrin (ZnTPP) is a corrosion inhibitor that forms a protective layer on the aluminum oxide (Al2O3) surface, acting as a barrier against corrosive agents. Objective: The electrodeposition of a sacrificial layer of Al2O3 with ZnTPP was carried out onto Ni- Ti orthodontic wire to enhance the corrosion resistance. Methods: 10 mM aluminum nitrate was dissolved in 10 mL of 0.1 M phosphate buffer solution (PBS), which was used as an electrolyte. Firstly, electrodeposition of Al2O3 on NiTi wire was carried out by using cyclic voltammetry by potential scanning between 0 and -2.0 V at a scan rate of 50 mV/s for 50 cycles. Secondly, 10 mL of 1 mM ZnTPP in 0.1 M PBS and ethanol (1:1) was prepared and used as an electrolyte. Electrodeposition of ZnTPP onto Al2O3/NiTi wire was achieved by cyclic voltammetry through the potential window of 0 to -2.0 V at a scan rate of 50 mV/s for 50 cycles. Results: The ZnTPP/Al2O3/NiTi wire displayed a potentiodynamic polarization resistance of 412931 Ω, with high stability compared to the bare NiTi wire (396421 Ω). Additionally, the corrosion rate for the ZnTPP/Al2O3/NiTi wire was measured as 0.254 mm/year, which was notably lower than that of the bare NiTi wire (0.540 mm/year). This decrease in corrosion rate can be attributed to the presence of the ZnTPP/Al2O3 film, which renders the NiTi wire electrically insulative and significantly increases its impedance compared to the bare NiTi wire. Conclusion: The bilayer coating of Al2O3 and ZnTPP has proven to significantly improve the corrosion resistance and stability of the wires. Thus, these materials can be considered for coating orthodontic archwires with improved corrosion stability.