Search Results (93)

This review summarizes the base materials, joining methods, filler materials, and principal technical challenges in endoscope joining fabrication, and proposes practical strategies to improve joint reliability under clinical constraints. We conducted a comprehensive search in multiple databases, including Web of Science, Google Scholar, patent databases, Scopus databases, and Medline (via PubMed), for articles on the joining for precision endoscope fabrication, covering the period from 1950 to 2026. We employed the combinations of keywords, “endoscopy”, “minimally invasive surgery”, “welding”, “joining”, “sealing”, “soldering”, “bonding”, and “brazing”. Approximately 500 references were retrieved. After excluding duplicates and irrelevant studies, 158 publications met the inclusion criteria. Data on base materials, joining, processes, filler materials, and technical issues related to sterilization, corrosion, and microstructural evolution were extracted and analyzed. Endoscopes are multi-material systems, involving metallic biomaterials (stainless steels (SSs), titanium alloys, nickel-based alloys, etc.), optical functional materials (glass, sapphire, quartz, etc.), engineering plastics, ceramics, composite materials, and coatings. Joining, sealing, and functional integration have been achieved via adhesive bonding, laser soldering, laser brazing, wave soldering, reflow soldering, fusion welding, and other joining techniques. The main challenges include how to reliably join highly mismatched dissimilar materials, how to fabricate low-residual-stress joints, and how to increase the long-term resistance to sterilization-induced degradation and thermal aging over repeated 100–200 °C thermal cycles. Conventional joining techniques struggle to balance mechanical integrity, joint hermeticity, and long-term stability under such harsh cyclic conditions. The resulting joints may suffer surface yellowing, interfacial debonding, microcracking, delamination, or progressive property degradation during service. We propose the following three strategies to achieve reliable, low-residual-stress, and sterilization-resistant joining of dissimilar materials for endoscopes: (1) A synergistic design that combines thin-film engineering (including evaporation, sputtering, and electroplating) with silver anti-oxidation layers is proposed to reduce residual stresses and to enhance the joint hermeticity. (2) To develop principles for the selection of multi-joining processes to achieve the multi-material integration and functional assembly of dissimilar material components. (3) To develop the laser-based joining methods (fusion, brazing, or braze-welding) for precision control of heat input, bonding quality, and the least damage to the heat-sensitive components. Full article

Plating on Plastics (PoP) requires specific surface pre-treatment steps to enable metallization. The conventional PoP industry utilizes hexavalent chromium (toxic, carcinogenic) and palladium (critical raw material) for surface etching and activation, respectively, raising significant health, environmental, and economic concerns. This work is based on a new Cr⁶⁺-free and Pd-free PoP technology that uses piranha (H₂O₂-H₂SO₄) solutions for surface etching, nickel salts for activation, and NaBH₄ for reduction, ultimately forming metallic nucleation sites for downstream electroless plating and electroplating. A comprehensive modeling approach was developed to simulate and predict unit operation performance (reaction kinetics and yields) and material properties (contact angle and adhesion) across processing stages of the new technology. State-of-the-art and data-driven modeling revealed the combinatorial relationships among process performance, the achieved properties and the different settings of process operating conditions. The results also highlighted capabilities for tuning all processes over a range of conditions, reaching desired product specifications (adhesion and thickness). The models were constructed as a Decision Support Tool (DST) serving economic, environmental, safety and Safe and Sustainable by Design (SSbD) objectives. The DST can be used through a user-friendly interface that enables the insertion of user-defined inputs and monitoring of optimization results. Full article

Nickel foam filtration layers used in sand control screens for petroleum extraction often suffer from insufficient mechanical strength and poor corrosion resistance and wear resistance. In this work, a two-stage electroplating strategy using the same metal was employed to construct hierarchical nickel coatings on nickel foam substrates. The effects of key process parameters, including electroplating time, temperature, and pretreatment, on the microstructure, mechanical properties, electrochemical corrosion behavior, and tribological performance of the coatings were systematically investigated. Electroplating time was found to directly regulate grain size and coating uniformity, while electroplating temperature significantly influenced nickel deposition behavior and electrolyte stability. In addition, UV pretreatment markedly improved the brightness and homogeneity of the deposited layers. Under optimized conditions (UV pretreatment for 10 min, electroplating at 60 °C for 8 min), a dense and uniform nickel coating with a well-ordered crystalline structure was obtained, leading to significantly enhanced hardness, wear resistance, and corrosion resistance. This study presents a practical and highly reliable approach for fabricating high-performance nickel-based coatings on nickel foam filter layers. Anticipated for application in the oil extraction industry, this method is set to enhance the performance of foam metal sand control layers. Full article

The development and deployment of robust technical solutions for sustainability improvement have become increasingly critical in response to growing environmental and social pressures while maintaining economic viability, particularly in industrial systems that require multi-stage technology implementation. Identifying such solutions requires the systematic treatment of significant uncertainties that affect sustainability-related decision-making. Among these, epistemic uncertainty, arising from incomplete or imperfect knowledge, is inherently subjective and, in principle, reducible. Fuzzy set theory provides an effective and well-established framework for representing and managing epistemic uncertainty in sustainability analysis. In this work, a fuzzy decision-making framework is proposed to support multi-stage technology development and deployment for dynamic sustainability performance improvement in industrial systems. The framework integrates comprehensive sustainability assessment with fuzzy representations of epistemic uncertainty to enable consistent comparison of alternative strategies at each implementation stage. It identifies the most appropriate strategy at each stage while ensuring alignment with long-term sustainability objectives. The proposed approach functions as a decision-support tool for guiding adaptive, stage-wise technology deployment under uncertainty. A case study of a nickel electroplating system is presented to demonstrate the applicability and effectiveness of the methodology. Full article

Ni removal from waste streams wherein it is present in organically complexed forms remains a major industrial challenge since organically bound Ni does not readily precipitate and is poorly removed by conventional adsorbents. In this work, two effective adsorbents, namely thin-layered porous carbon (TLPC) and MnO₂-decorated TLPC (i.e., MnO₂-TLPC), were developed for the removal of both inorganic and organically complexed Ni(II) from synthetic and real waste streams. Both adsorbents removed inorganic Ni(II) as well as Ni(II) present in organically complexed forms, achieving up to ~80% removal from both real and synthetic electroplating wastewater. Critically, Ni removal efficiencies were maintained over five adsorption–desorption cycles, demonstrating excellent regeneration and reuse potential. The Ni removal by TLPC was pH-dependent, whereas MnO₂-TLPC showed minimal pH sensitivity. TLPC relies on outer-sphere, charge-driven adsorption, whereas MnO₂-TLPC achieves stronger Ni binding through inner-sphere complexation promoted by oxygen- and nitrogen-based functional groups. The sorbents also reduced dissolved organic carbon, with TLPC displaying higher organic removal efficiency. Mechanistic analysis indicates that Ni uptake is primarily governed by sorption of both complexed and inorganic Ni(II) present in equilibrium with the complex, combined with sorption of the free ligand itself. The sorption of the free ligands and inorganic Ni(II) drive Ni–ligand decomplexation in the solution phase, enabling further Ni removal. Overall, TLPC provides a low-cost, high-performance option for treating alkaline wastewaters with elevated Ni and organic loadings, while MnO₂-TLPC offers robust, pH-resilient removal under circumneutral conditions. These findings position both materials as promising candidates for practical wastewater treatment applications targeting complexed metal contaminants. Full article

This study evaluates the hydrogen embrittlement (HE) resistance of nickel-based electroplated coatings applied on cold-finished mild steel, with emphasis on their performance as diffusion barriers to impede hydrogen ingress. Nickel coatings were deposited using Watts plating bath under controlled electroplating parameters. Electrochemical hydrogen charging was performed in an alkaline medium at progressively increasing charging current densities to simulate varying levels of hydrogen exposure. Tensile testing was conducted immediately after charging to assess the mechanical response of both uncoated and nickel-coated specimens, focusing on key properties such as elongation, yield strength, ultimate tensile strength, and toughness. The results revealed a gradual degradation in ductility and toughness for the uncoated steel samples with increasing hydrogen content. In contrast, the nickel-coated specimens maintained mechanical stability up to a critical hydrogen threshold, beyond which a pronounced reduction in tensile response was observed. Fractographic analysis supported these trends, revealing a transition from ductile to brittle fracture characteristics with increasing concentrations of hydrogen. These findings highlight the protective capabilities and limitations of nickel-based coatings in mitigating hydrogen-induced degradation, offering insights into their application in industries where hydrogen embrittlement of structural materials is a major concern. Full article

Metal electrodeposition on additively manufactured lattice structures enables the creation of functionally graded hybrid components with enhanced mechanical properties. However, predicting coating thickness distribution remains challenging due to complex current density fields in intricate geometries. This study develops and validates a finite element electrochemical simulation model for predicting coating thickness distribution in lattice structures using COMSOL Multiphysics 6.1. The model incorporates Butler–Volmer electrode kinetics, mass transport limitations, and the Laplace equation for current distribution. Experimental validation was performed using FCCZ lattice structures electrochemically coated with nickel for 24 h at 200 A/m². CT scanning analysis revealed mean absolute errors of 5.25% between simulation and experiment after model calibration. The validated model successfully captures the exponential coating gradient from exposed edges to internal regions and provides a robust predictive tool for coating thickness distribution, which is essential for the effective design and optimization of electrochemically metallized lattice structures. Full article

Mechanical forces, chemical and electrochemical reactions, and environmental variables can all lead to surface degradation of parts. Composite coatings can be applied to these materials to enhance their surface characteristics. Recently, nickel-based composite coatings have gained greater attention because of their remarkable wear resistance. The efficiency, precision, and affordability of this process make it a popular method. In addition, electroplating nickel-based composites offers a more environmentally friendly alternative to traditional dangerous coatings such as hard chrome. Tribological and wear characteristics are highly dependent on several variables, such as particle parameters, deposition energy, fluid dynamics, and bath composition. Mass loss, coefficient of friction, hardness, and roughness are quantitative properties that provide useful information for coating optimization and selection. Under optimized electrodeposition conditions, the Ni-SiC-graphite coatings achieved a 57% reduction in surface roughness (Ra), a 38% increase in microhardness (HV), and a 25% reduction in wear rate (Ws) compared to pure Ni coatings, demonstrating significant improvements in tribological performance. Overall, the incorporation of SiC nanoparticles was found to consistently improve microhardness while graphite or MoS₂ reduces friction. Differences in wear rate among studies appear to result from variations in current density, particle size, or test conditions. Furthermore, researchers run tribology studies and calculate the volume percentage using a variety of techniques, but they fall short in providing a sufficient description of the interface. This work primarily contributes to identifying gaps in tribological research. With this knowledge and a better understanding of electrodeposition parameters, researchers and engineers can improve the lifespan and performance of coatings by tailoring them to specific applications. Full article

Exposure to nickel (Ni) and chromium (Cr) in environmental and occupational settings appears to be inevitable and significantly affects the liver, the principal organ responsible for their metabolic processes. This research aimed to assess the functional integrity of the liver and the molecular mechanisms underlying hepatic damage in employees exposed to Ni and Cr at work. A cross-sectional investigation was implemented with 86 non-smoking male employees working in a metallurgical factory. Serum Cr, Ni, liver function tests, oxidative and inflammatory indicators, and Keap-1, Nrf2, and miR-223 expression were assessed. In electroplating workers, serum Cr (2.47 ± 2 µg/L), Ni (1.39 ± 0.79 µg/L), liver transaminases, total bilirubin, and NF-κB were all statistically significantly greater than in the referent group. Electroplaters’ serum albumin levels were significantly lower than those of controls. Furthermore, oxidative stress was observed in electroplaters, characterized by lower levels of superoxide dismutase (SOD) and glutathione peroxidase (GPx) and greater levels of malondialdehyde (MDA) with respect to controls (p < 0.05). Additionally, compared to controls, gene expressions in electroplaters showed that Keap-1 was upregulated, while Nrf2/Ho-1 and miR-223 were downregulated. In conclusion, occupational exposure to Ni and Cr was associated with hepatic impairment through downregulation of the antioxidant Nrf2 pathway, oxidative stress, and inflammation. Full article

A novel heavy metal-resistant bacterium with significant bioremediation capabilities, Sinirhodobacter sp. 1C5-22 was isolated from moderately polluted Shenzhen Futian mangrove rhizosphere sediments. This strain showed exceptional tolerance (MIC ≥ 600 mg/L for Cu/Zn; > 500 mg/L for Ni). Analyses revealed distinct metal-specific distribution strategies: Cd and Ni were predominantly bound extracellularly (>80%); Cu was bound intracellularly (~60%); and Zn exhibited balanced partitioning. Integrated omics analysis identified a molecular defense mechanism coordinated by the CreB transcriptional regulator. This Adsorption–Sequestration–Efflux (ASE) system integrates extracellular polymer binding, periplasmic sequestration via stable metal-binding proteins, and efflux pump activity, resolving the apparent adsorption-tolerance paradox at elevated concentrations. For bioremediation applications, we developed a polyvinyl alcohol–sodium alginate immobilized consortium (PVA-SA 1C5-22). The engineered agent displayed significantly enhanced biosorption capacity compared to free cells and effectively mitigated heavy metal-induced oxidative damage, evidenced by stabilized malondialdehyde levels. It demonstrated robust reusability, maintaining high metal enrichment across five adsorption–desorption cycles in multi-metal wastewater with efficient HCl-driven desorption (55–70%). Critically, it achieved stable nickel removal performance (~20% adsorption, >50% desorption) from authentic electroplating wastewater (1850 mg/L Ni²⁺) through successive multiple cycles. Our integrated approach bridges microbial ecology and environmental biotechnology, establishing this immobilized system as a highly sustainable strategy for complex industrial effluent remediation. Full article

Hydroxamic acid extractants, such as LIX984, demonstrate high efficiency in extracting nickel from electron-free nickel waste solutions; however, they suffer from a slow extraction rate. This study investigated the effect of adding 2–5 vol.% of three organophosphate extractants (P507, P204, and Cyanex272) to LIX984. The results show that incorporating 2–5 vol.% of P507 or Cyanex272 significantly improves both extraction efficiency and kinetics. The addition of organophosphate extractants increased the extraction rate by 1.5–10 times, indicating a direct correlation between the extractant content and the acceleration of the extraction process, with higher concentrations yielding faster extraction. Compared to the use of LIX984 alone, where nickel extraction efficiency was only 46%, the addition of 5 vol.% P507 increased efficiency to over 99%, with a substantial improvement in extraction rate. Similarly, 2 vol.% P204 achieved a nickel removal efficiency of 99.8%. In non-electroplating waste solutions (pH 4–6), selective removal of iron and zinc impurities was achieved by first adding 2–5 vol.% P204 or P507, followed by adjusting the pH to 6–7 and using a mixture of organophosphate extractants. The spent electroless nickel plating baths were then treated with LIX984 combined with organophosphoric acid extractants, yielding nickel salt solutions of higher purity. Thus, P507, P204, and Cyanex272 serve as effective promoters for the hydroxamic acid extractant LIX984, resulting in both enhanced nickel extraction efficiency and faster extraction kinetics. Full article

Brass components are widely used in heat dissipation and thermal emission devices due to their high thermal conductivity and ease of processing. However, these applications demand good thermal oxidation resistance, high emissivity, and excellent corrosion resistance. In this study, nickel coatings were deposited on brass substrates by direct current electroplating, and the effects of current density and cathode configuration on the microstructure, emissivity, and corrosion resistance of the coatings were systematically investigated. The results show that the emissivity of the coatings first increased and then decreased with increasing current density. Optimal performance was achieved when the cathode and anode were positioned perpendicular to the horizontal plane at a current density of 3.0 A·dm⁻². Under these conditions, the coatings exhibited a smooth, uniform, and dense microstructure, with evenly distributed metallic grains. Electrochemical polarization and impedance measurements further confirmed the superior corrosion resistance of this coating, with a minimum corrosion current density of 0.259 μA·cm⁻², a maximum polarization resistance of 6381.55 Ω·cm², and a minimum corrosion rate of 0.023 mm/a. These findings demonstrate a simple and effective approach to enhancing both the emissivity and corrosion resistance of brass substrates, offering practical value for thermal management applications. Full article

This paper presents a rare example of the conservation of a piece of marine oval-shaped tableware, commonly known as a ‘cloche’, made of nickel silver with silver electroplating that was recovered in 2006 from the 19th-century Patris paddle-wheel shipwreck in Greece. Our study found that the cloche is made of two components of differing compositions of nickel-silver alloy, also known as German silver: a forged body and a cast handle, joined by lead soldering. The body also has an impressed decorative stamp bearing the ‘Greek Steamship’ signature in Greek. The condition assessment found the object was covered in thick concretion formations and suffered galvanic corrosion, along with dealloying, resulting in redeposition of copper. The conservation treatment carried out in 2007 is detailed along with diagnostic examination using microscopic analysis, radiographic imaging, and chemical analysis of the corrosion and metal, using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) and portable X-ray fluorescence (pXRF). The conservation of the object involved mechanical and chemical methods (formic acid 5–10% v/v, stabilisation treatment with sodium sesquicarbonate 1% w/v), including spot electrolysis, and the object was coated with 15% w/v Paraloid B72 in acetone. Since its conservation, the object has been on display in the Industrial Museum of Hermoupolis in Syros. In 2025, the object was inspected for its coated surface as well as to carry out pXRF again with a more advanced system to better understand the alloy composition of the object. These results are presented here for this unique object. Full article

At present, there are some challenging issues for diamond electroplating devices, such as poor particle–cathode contact uniformity, low conductivity, inefficient deposition, and complex disassembly/cleaning process of the device. To overcome these issues, an ultrasonic oscillation-assisted nickel electroplating device is innovatively designed and presented in this paper. The device features: (1) innovative architecture enabling rapid disassembly; (2) ultrasonic enhancement of diamond particle mobility (frequency × amplitude); (3) optimized electrical contact interfaces. In this paper, the effects of electroplating current, output power of ultrasonic oscillator and diamond particle size on nickel electroplating onto diamond surface are further studied particularly by ultrasonic assisted electroplating. The experimental results show that the ultrasonic oscillation assisted electroplating greatly improves the uniformity of the coating on the diamond surface and effectively prevents the adhesion between diamond particles. While the process parameters are electroplating current of 3 A, output power of ultrasonic oscillator 900 W, diamond particle size of 120/140, the weight-gain rate is 20.6%, the nickel content of the coating reaches 81.95%, and the coating is excellent uniformed without agglomeration. The research presented provides fundamental understanding for further development and application of ultrasonic oscillation-assisted electroplating technology particularly for broad precision engineering purposes. Full article

To achieve superior interfacial bonding between carbon fibers and an Al matrix, this study employed a simplified electroplating system to deposit Ni coatings on carbon fibers using an additive-free electrolyte. The investigation first optimized the carbon fiber heat treatment process, followed by systematic examination of electroplating parameters affecting the Ni coating microstructure. Key findings demonstrate that (1) thermal treatment of carbon fibers significantly enhances their wettability with the electroplating solution; (2) controlled deposition of smooth, uniform, and continuous Ni coatings requires precise optimization of nickel sulfate concentration, applied voltage, and pH value. This work establishes a cost-effective technical foundation for producing high-quality Ni-coated carbon fibers. Full article