Search Results (50)

In this work, an experimental investigation is conducted with the aim of optimizing the electrodeposition parameters for Ni-Al₂O₃ composite coatings using the Taguchi method. The presented research is structured into two complementary sections. The first segment investigates the characteristics of Ni and Ni-Al₂O₃ coatings, specifically Al₂O₃ particle incorporation and crystallinity variations, using X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and hardness evaluation through micro-indentation testing. The second section uses statistical techniques, specifically Analysis of Variance (ANOVA) and signal-to-noise (S/N) ratio analysis, to determine which parameters have the most impact on the experimental results. ANOVA and the Response Surface Methodology (RSM) were used in a modeling technique to forecast and optimize the technical responses. Based on an L16 orthogonal design, sixteen tests were carried out to investigate the effects of several important variables, including agitation rate (200–350 rpm), deposition period (15–60 min), alumina concentration (10–25 g.L⁻¹), and current density (2–5 A.dm⁻²). The conditions for optimizing microhardness (HV) and Al₂O₃ integration while limiting average crystallite size (ACS) were identified using the most suitable function. The obtained results reveal significant improvements in the composite coating’s properties, including a 164% increase in microhardness, a 400% rise in alumina incorporation, and a notable reduction in crystallite size, demonstrating the efficacy of the electrodeposition process and optimization strategy adopted. Full article

The traditional hot-dip tinning processes face challenges in controlling excessive copper dissolution and interfacial instability. This study involved designing a dissolution experiment using the hot-dip tin plating process. Through microscopic characterization and dissolution kinetics analysis, it systematically revealed the regulatory mechanism of trace Ni addition (0–0.5 wt.%) on the dissolution behavior and interfacial reaction of copper wire in a tin alloy melt. The experiment showed that Ni atoms formed a (Cu_1−x,Ni_x)₆Sn₅ ternary phase by replacing Cu in the Cu₆Sn₅ lattice, resulting in a transformation of the grain morphology of the IMC layer from equiaxed to fibrous. At the same time, the addition of Ni changed the kinetics of the interfacial reaction, effectively increasing the activation energy from 40.84 kJ/mol in the pure Sn system to 54.21 kJ/mol in the Sn-0.5Ni system, which extended the complete dissolution time of the copper wire at 573 K by three times. Full article

This review analyzes TiO₂-based coatings formed by the plasma electrolytic oxidation (PEO) process of titanium for the photocatalytic degradation of methyl orange (MO) under simulated solar irradiation conditions. PEO is recognized as a useful technique for creating oxide coatings on various metals, particularly titanium, to assist in the degradation of organic pollutants. TiO₂-based photocatalysts in the form of coatings are more practical than TiO₂-based photocatalysts in the form of powder because the photocatalyst does not need to be recycled and reused after wastewater degradation treatment, which is an expensive and time-consuming process. In addition, the main advantage of PEO in the synthesis of TiO₂-based photocatalysts is its short processing time (a few minutes), as it excludes the annealing step needed to convert the amorphous TiO₂ into a crystalline phase, a prerequisite for a possible photocatalytic application. Pure TiO₂ coatings formed by PEO have a low photocatalytic efficiency in the degradation of MO, which is due to the rapid recombination of the photo-generated electron/hole pairs. In this review, recent advances in the sensitization of TiO₂ with narrow band gap semiconductors (WO₃, SnO₂, CdS, Sb₂O₃, Bi₂O₃, and Al₂TiO₅), doping with rare earth ions (example Eu³⁺) and transition metals (Mn, Ni, Co, Fe) are summarized as an effective strategy to reduce the recombination of photo-generated electron/hole pairs and to improve the photocatalytic efficiency of TiO₂ coatings. Full article

The influence of sulfide (S²⁻) concentration on the corrosion resistance of Cr₃C₂-25(Ni20Cr) cermet coating on Al7075 (EN, AW-7075) substrate (Cr₃C₂-25(Ni20Cr)/Al7075) was investigated. The coating was produced by the cold-sprayed (CS) method. The Cr₃C₂-25(Ni20Cr)/Al7075 coatings were modified chemically in solutions containing thioacetic acid amide (TAA). The surface and microstructure of the specimens were both observed by a scanning electron microscope (SEM). The mechanical properties of the Cr₃C₂-25(Ni20Cr) coatings were characterized using microhardness (HV) measurements. The corrosion tests of the materials were carried out using the electrochemical method in a acidic chloride solution. The adsorbed (Me_mS_n)_ads layer effectively separates the Cr₃C₂-25(Ni20Cr)/Al7075 coating surface from contact with the aggressive corrosive environment. More than a twice lower value of corrosion rate (CW) was obtained for the Cr₃C₂-25(Ni20Cr)/Al7075 coating after exposure to the environment with 0.15 M TAA. Full article

Fiber coatings protect the glass surface of fiber from extrinsic environmental factors. The coating of shape memory alloy over fiber is useful in sensor fabrication where the state of deformation is affected by the phase transformation of the coated material. In addition, coated plastic fibers can be used in elevated temperature environments. To this end, the present research aims to investigate the effect of the Ni-Ti-Sn composite coating over the fiber. Homogeneous particle distribution, agglomeration, porosity and the ability to obtain uniform coating thickness have been general concerns in fiber coatings. Hence, the present study comprehensively investigated the mechanical and thermal behavior as well as morphological properties of Ni-Ti-Sn nanopowders deposited on polymer fiber optics. Five sets of polyamide-coated samples with different Ni-Ti-Sn proportions were fabricated and characterized. Morphological studies confirmed that an even coating thickness enhanced the mechanical integrity and optical performance. The optimum composition demonstrated superior tensile strength of 29.5 MPa and a 25% increase in elongation compared to the uncoated sample. The Ni-Ti-Sn alloy composition investigated in the present study is promising for industrial applications where thermal stability and mechanical performance are warranted. Full article

Multifunctional coatings based on Sn-Ni materials with and without titanium oxide nanoparticles (TiO₂NPs) incorporation were prepared using the electrochemical deposition technique at 70 °C. TiO₂NPs were dispersed in the electrolyte bath, and their influence on the surface texture, crystalline phase, and properties was investigated. Various techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray microanalysis (EDX) were used to characterize the prepared coatings. The formation mechanism of the deposited coatings has been demonstrated to be consistent with the electrochemical behavior of instantaneous growth, and the three-dimensional growth is controlled by diffusion phenomena. The anticorrosion effectiveness of the coatings was assessed using potentiodynamic polarization curves and electrochemical impedance spectroscopy in an artificial sweat medium, while the bactericidal activity of the composite coatings (the ability to induce cell death) was evaluated in accordance with the ISO 27447:2019 test. The influence of TiO₂NPs at a low concentration of 1 g/L on the composition, structure, and properties of the deposited coatings was demonstrated. Particular attention was paid to the relationship between the anticorrosive and bactericidal properties of the coatings and their structure composition and wetting properties. The synergistic effect of chemical composition and surface-wetting properties has been demonstrated to enhance the anticorrosive and bactericidal properties of the prepared coatings. Full article

With the rapid development of the advanced electronic packaging field, the requirements for the connection between solder and Cu substrate are becoming increasingly stringent. Currently, the commonly used Ni-P diffusion barrier layer in the industry lacks long-term reliability, and its resistivity is higher than that of other substrates. This paper introduces the highly conductive metal element W to modify the binary Ni-P coating and prepares a ternary Ni-W-P coating through electrodeposition to improve this situation. The key parameters for the electrodeposition of ternary Ni-W-P are determined. The isothermal aging reaction of Ni-W-P with Sn-Bi solder at 100 °C was studied, and the results showed that, compared to the conventional Ni-P coating, the Ni-W-P barrier coating with higher W content has a much longer lifespan as a barrier layer and exhibits significantly better electrical conductivity. Additionally, the reaction mechanism between Ni-W-P and the Sn-Bi solder is proposed. This research presents a promising advancement in the development of barrier layers for electronic packaging, potentially leading to more reliable and efficient electronic devices. Introducing tungsten into the Ni-P matrix not only extends the lifespan of the coating but also enhances its electrical performance, making it a valuable innovation for applications requiring high conductivity and durability. This study could guide further investigations into the application of ternary coatings in various electronic components, paving the way for improved designs and materials in the semiconductor industry. Full article

As the integration of chips in 3D integrated circuits (ICs) increases and the size of micro-bumps reduces, issues with the reliability of service due to electromigration and thermomigration are becoming more prevalent. In the practical application of solder joints, an increase in the grain size of intermetallic compounds (IMCs) has been observed during the reflow process. This phenomenon results in an increased thickness of the IMC layer, accompanied by a proportional increase in the volume of the IMC layer within the joint. The brittle nature of IMC renders it susceptible to excessive growth in small-sized joints, which has the potential to negatively impact the reliability of the welded joint. It is therefore of the utmost importance to regulate the formation and growth of IMCs. The following paper presents the electrodeposition of a Ni-W layer on a Cu substrate, forming a barrier layer. Subsequently, the barrier properties between the Sn/Cu reactive couples were subjected to a comprehensive and systematic investigation. The study indicates that the Ni-W layer has the capacity to impede the diffusion of Sn atoms into Cu. Furthermore, the Ni-W layer is a viable diffusion barrier at the Sn/Cu interface. The “bright layer” Ni₂WSn₄ can be observed in all Ni-W coatings during the soldering reflow process, and its growth was almost linear. The structure of the Ni-W layer is such that it reduces the barrier properties that would otherwise be inherent to it. This is due to the “bright layer” Ni₂WSn₄ that covers the original Ni-W barrier layer. At a temperature of 300 °C for a duration of 600 s, the Ni-W barrier layer loses its blocking function. Once the “bright layer” Ni₂WSn₄ has completely covered the original Ni-W barrier layer, the diffusion activation energy for Sn diffusion into the Cu substrate side will be significantly reduced, particularly in areas where the distortion energy is concentrated due to electroplating tension. Both the “bright layer” Ni₂WSn₄ and Sn will grow rapidly, with the formation of Cu-Sn intermetallic compounds (IMCs). At temperatures of 250 °C, the growth of Ni₃Sn₄-based IMCs is controlled by grain boundaries. Conversely, the growth of the Ni₂WSn₄ layer (consumption of Ni-W layer) is influenced by a combination of grain boundary diffusion and bulk diffusion. At temperatures of 275 °C and 300 °C, the growth of Ni₃Sn₄-based IMCs and the Ni₂WSn₄ layer (consumption of Ni-W layer) are both controlled by grain boundaries. The findings of this study can inform the theoretical design of solder joints with barrier layers as well as the selection of Ni-W diffusion barrier layers for use in different soldering processes. This can, in turn, enhance the reliability of microelectronic devices, offering significant theoretical and practical value. Full article

In this study, a novel friction-assisted jet electrodeposition technology was applied to prepare bronze coating on 40CrNiMoA structural steel surfaces. The bronze electrode was designed with internal flow channels and nozzles, and the friction brushes made of alumina and silicon carbide were connected to the electrode surface. It was reported that the quality and deposition rate of the thick bronze coatings were significantly improved with friction-assisted jet electrodeposition. The roughness and microstructures were refined, and the deposition rate was up to 100 μm/h when the current density was 8 A/dm². In addition, the chemical composition was related to current density as the content of tin in the bronze coating made with FJED decreased at a high current density. Moreover, the grain structures were α-CuSn in the solid-solution phase and the average grain size of FJED coatings was refined at a current density of 8 A/dm². Full article

Sn–Ni alloy matrix coatings co-deposited with TiO₂ nanoparticles (Evonik P25) were produced utilizing direct (DC) and pulse electrodeposition (PC) from a tin–nickel chloride-fluoride electrolyte with a loading of TiO₂ nanoparticles equal to 20 g/L. The structural and morphological characteristics of the resultant composite coatings were correlated with the compositional modifications that occurred within the alloy matrix and expressed via a) TiO₂ co-deposition rate and b) composition of the matrix; this was due to the application of different current types (DC or PC electrodeposition), and different current density values. The results demonstrated that under DC electrodeposition, the current density exhibited a more significant impact on the composition of the alloy matrix than on the incorporation rate of the TiO₂ nanoparticles. Additionally, PC electrodeposition favored the incorporation rate of TiO₂ nanoparticles only when applying a low peak current density (J_p = 1 Adm⁻²). All of the composite coatings exhibited the characteristic cauliflower-like structure, and were characterized as nano-crystalline. The composites’ surface roughness demonstrated a significant influence from the TiO₂ incorporation rate. However, in terms of microhardness, higher co-deposition rates of embedded TiO₂ nanoparticles within the alloy matrix were associated with decreased microhardness values. The best wear performance was achieved for the composite produced utilizing DC electrodeposition at J = 1 Adm⁻², which also demonstrated the best photocatalytic behavior under UV irradiation. The corrosion study of the composite coatings revealed that they exhibit passivation, even at elevated anodic potentials. Full article

In order to expand the application field of attapulgite in tribology, the tribological properties of attapulgite as a lubricant additive on electric-brush plated Ni coating were investigated using the ball-disc contact mode of a SRV-IV friction and wear tester. The worn surfaces were characterized and analyzed via scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). Results indicated that the friction-reducing and antiwear properties of 150 SN lubricating oil on the Ni coating were remarkably improved by an appropriate amount of attapulgite. Tribofilm mainly composed of Ni, NiO, SiO₂, Al₂O₃, graphite, and organic compounds was formed on the worn surface under the action of attapulgite, which was responsible for the reduction of friction and wear. Full article

Usually, electronic tongues (e-tongue) do not require specific interactions to discriminate aqueous solutions. Among the several factors which determine the electrical properties of sensing units, the interactions between liquids and interfaces have a crucial role. Here, we explore the interaction between dioctadecyldimethylammonium bromide (DODAB) lipid and carbendazim (MBC) pesticide in an e-tongue to discriminate different MBC concentrations in aqueous solutions. The sensing units were fabricated of gold interdigitated electrodes (IDEs) coated with layer-by-layer (LbL) films of DODAB and nickel tetrasulfonated phthalocyanine (NiTsPc), perylene and 1,2-dipalmitoyl-sn-glycero-3-phospho-(1′-rac-glycerol) (DPPG), namely (DODAB/NiTsPc)₅ and (Perylene/DPPG)₅, respectively. Besides, a bare electrode also constituted the e-tongue to distinguish MBC concentrations from 1.0 × 10⁻⁷ up to 1.0 × 10⁻¹⁰ mol L⁻¹, by impedance spectroscopy. In addition, the experiment was optimized using two IDE geometries. The LbL films were manually fabricated obtaining linear growth monitored via UV-Vis absorption spectroscopy. Optical images associated with chemical mapping reveals the presence of small aggregates in the DODAB/NiTsPc LbL film surface. Although the e-tongue was able to discriminate all MBC concentrations by means of the interactive document map (IDMAP), only the sensing unit covered with DODAB/NiTsPc LbL film presented a satisfactory response. According to the equivalent circuit, the main contribution arises from the bulk and film surface due to the interaction between DODAB and MBC, indicating THE sensitivity of the sensing unit. Finally, the adsorption of MBC molecules onto the film surface induced an irreversible process, although there are some frequencies at which the sensing unit response seems to be reversible, as shown by parallel coordinates. Full article

This paper presents an assessment of the effect of isothermal annealing of Sn whisker growth behavior on the surface of Sn0.7Cu0.05Ni solder joints using the hot-dip soldering technique. Sn0.7Cu and Sn0.7Cu0.05Ni solder joints with a similar solder coating thickness was aged up to 600 h in room temperature and annealed under 50 °C and 105 °C conditions. Through the observations, the significant outcome was the suppressing effect of Sn0.7Cu0.05Ni on Sn whisker growth in terms of density and length reduction. The fast atomic diffusion of isothermal annealing consequently reduced the stress gradient of Sn whisker growth on the Sn0.7Cu0.05Ni solder joint. It was also established that the smaller (Cu,Ni)₆Sn₅ grain size and stability characteristic of hexagonal η-Cu₆Sn₅ considerably contribute to the residual stress diminished in the (Cu,Ni)₆Sn₅ IMC interfacial layer and are able to suppress the growth of Sn whiskers on the Sn0.7Cu0.05Ni solder joint. The findings of this study provide environmental acceptance with the aim of suppressing Sn whisker growth and upsurging the reliability of the Sn0.7Cu0.05Ni solder joint at the electronic-device-operation temperature. Full article

The application of a higher corrosion resistance coating modified with nano additions can effectively decrease or prevent corrosion from occurring. In the present work, a novel method is successfully developed for the modification of carbon steel surfaces aiming for high corrosion resistance using Sn—4% Zn alloy/nanoparticle composite (NiO+ Al₂O₃) coating. Sn—4% Zn alloy/nanoparticle composite (NiO+ Al₂O₃) coatings were deposed on carbon steel using a direct tinning process that involved a power mixture of Sn—4% Zn alloy along with a flux mixture. Regular coating and interface structures were achieved by individual Al₂O₃ and both NiO and Al₂O₃ nanoparticle combined additions in the Sn-Zn coating. The maximum coating thickness of 70 ± 1.8 µm was achieved for Al₂O₃ nanoparticles in the Sn-Zn coating. Interfacial intermetallic layer thickness decreased with all used nanoparticle additions in individual and hybrid conditions. The minimum intermetallic layer thickness of about 2.29 ± 0.28 µm was achieved for Al₂O₃ nanoparticles in the Sn—Zn coating. Polarization and impedance measurements were used to investigate the influence of the incorporated Al₂O₃, NiO, and hybrid Al₂O₃/NiO nanoparticles on the passivation of the low-carbon steel (LCS) corrosion and the coated Sn—Zn LCS in sodium chloride solution. It was found that the presence of Al₂O₃, NiO, and Al₂O₃/NiO nanoparticles remarkably improved the corrosion resistance. The corrosion measurements confirmed that the corrosion resistance of the coated Sn-Zn carbon steel was increased in the presence of these nanoparticles in the following order: Al₂O₃/NiO > NiO > Al₂O₃. Full article

In this study, nitrogen-doped nickel graphene core cells (N-NiGR) are synthesized using the thermal chemical vapor deposition method. The structural, morphological, and chemical composition properties of N-NiGR are investigated using X-ray diffractometry (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), respectively. N-NiGR has shown potential as a material that can assist charge carrier transportation in the photoactive a layer of planar hybrid solar cell (PHSC) owing to its high charge carrier mobility and stability with the solution process. Here, we investigated for the first time an enhancement of the solar cell efficiency (by up to a 2% increase) in PHSCs by incorporating the charge selective N-NiGR into the device’s photoactive layer. Synthesized N-NiGR with different concentrations are incorporated into the active layer of the devices as charge transport material. The device structure of an ITO-coated glass/Hole transport layer/(PBT7+N-NiGR+SnS)/Electron transport layer/Cathode is fabricated and the maximum power conversion efficiency of the device was observed to be about 4.35%. Full article