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In this study, a copper brazing filler metal coating is fabricated on a 304 stainless steel (304SS) substrate using an electroplating technique. The effect of using electroplated copper brazing filler metal coatings compared to pure copper foil of the same thickness for vacuum brazing of stainless steel joints is investigated. The microstructure and microhardness of the brazed joints are characterized using X‐ray diffraction (XRD), scanning electron microscopy (SEM), and a Vickers hardness tester. The shear strength of the brazed joints is measured using an INSTRON 5869 universal testing machine. The results indicate that the electroplated Cu coating is dense, predominantly with a single cubic phase, with a few copper particles aggregating on the surface. Under electroplating conditions of 20 mA cm−2 for 1 h, the coating thickness was 56 μm. The shear strength of the brazed joint with this coating reached a maximum of 333.7 MPa, which is higher than that of a brazed joint with a 60 μm thick copper foil, which exhibits a shear strength of 303.2 MPa. The shear strength of the brazed joints shows an initial increase followed by a decrease as current density and electroplating time increase. This study provides significant technical support for brazing complex shapes or precision components. It suggests a method to simplify the brazing process, reduce production costs, and enhance the strength of brazed joints. [ABSTRACT FROM AUTHOR]

The development of protective coatings on copper alloy surfaces represents a critical research direction to enable the widespread industrial application of copper alloys. To improve the corrosion resistance and wear resistance of the copper alloy plates, a Ni-Cr-Co-based multi-principal element alloy coating was prepared via high-velocity oxygen fuel (HVOF). Then, the microstructure, corrosion resistance, and wear resistance of the Ni-Cr-Co coating and the electroplated NiCo coating were analyzed comparatively. The research results show that the phases of the Ni-Cr-Co coating contained face-centered cubic (FCC) solid solution, CrB and M23C6. The NiCo coating exhibited a single-phase FCC solid solution structure. Compared to the NiCo coating, the corrosion current density of the Ni-Cr-Co coating was reduced by 92.1% in NaF solution. A highly protective passive film was formed on the Ni-Cr-Co coating, and its low ΣCSL grain boundary proportion reached as high as 25.7%. Therefore, the Ni-Cr-Co coatings demonstrated superior corrosion resistance. The scratch wear coefficient of the Ni-Cr-Co coating was only 51.9% of that of the NiCo coating, due to the synergistic strengthening of the matrix and hard second phase. This research offers technical support and a theoretical basis foundation for the development of coatings on copper alloys with excellent corrosion resistance and wear resistance. [ABSTRACT FROM AUTHOR]

To reduce the corrosion degradation of copper alloys, an equiatomic CoCrNi medium-entropy alloy (MEA) coating was successfully fabricated on a copper alloy plate using high-velocity oxygen-fuel (HVOF) spraying. The microstructure, corrosion behaviour, and passive film characteristics of the CoCrNi MEA coating in a 3.5 wt.% NaCl solution were investigated. The CoCrNi MEA coating mainly consisted of a face-centred cubic solid solution structure and a small amount of metal oxide. Compared to that of the widely used electroplated NiCo coating, the corrosion current density of the CoCrNi MEA coating dropped by 93%. The pitting corrosion of the CoCrNi MEA coating originated from the interface between the solid solution matrix and the oxide. Due to the strong protective passive film and low coincident site lattice boundaries, the CoCrNi MEA coating exhibited superior corrosion resistance in a NaCl solution. [ABSTRACT FROM AUTHOR]

The concept of solderability is rigorously defined, accompanied by the proposal of quantitative criteria for its assessment. A comprehensive categorization of solderable materials into three distinct groups—namely, easily solderable, moderately solderable, and unsolderable—is proposed based on solderability parameters. Practical recommendations are given for the effective deployment of solderability testing methodologies across a spectrum of materials and electronic components. Detailed expositions are offered on the methods employed in the evaluation of solderability, encompassing solder immersion, measurement of solder spreading area, and assessment of capillary penetration into gaps. Schematic representations of these evaluation techniques, alongside descriptions of the requisite apparatus for their implementation, are presented. Furthermore, tabulated data on the solder spreading factors for diverse categories of chemical and electroplated coatings, including hot tinning, are given. Prolonged storage may lead to the formation of oxide films on the surface of coatings, thereby deteriorating solderability. To enhance the quality of electroplated coatings, it is recommended to employ periodic currents in nonstationary electrolysis modes during the deposition of electroplated coatings. [ABSTRACT FROM AUTHOR]

In this study, the wear resistance of nickel (Ni)–cellulose nanofiber (CNF) composite electroplated films on steel plates (JIS SPCC, cold-rolled steel) was evaluated, including their surface and microstructural properties. In the CNF sample, 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO)-oxidized CNF was used. As a result of the ball-on-disk abrasion test, in which steel (SUJ2) balls were used as the counterpart material, the plated film obtained with the addition of 1 g/L of CNF to the plating solution showed the highest wear resistance in this study. Compared to the conventional Ni-plated film without CNF, the abrasion loss volume on the plated side was reduced by approximately 79%, and that on the ball side was reduced remarkably by 94%. A microstructural analysis of the abrasion scars showed areas where co-deposited CNFs were stretched in the direction of abrasion, suggesting that the wear reduction effect was caused by sliding between the individual CNFs within the aggregates. Moreover, the hardness of the plated film increased when the Ni crystallite size became finer. It was confirmed that the co-deposition of fine CNFs is effective in improving hardness, whereas the co-deposition of a certain degree of aggregated CNFs is effective in exhibiting the wear reduction effect. [ABSTRACT FROM AUTHOR]

Nanocrystalline nickel coatings can be electrodeposited by using grain refiners like saccharin which consequently increase the gloss of the coating. Also, brighteners can produce bright coatings. The aim of this research was to compare the brightness of electroplated nanocrystalline nickel coating with traditional electroplated bright nickel coating. The coatings prepared from the bath containing saccharin and a bath with para-toluene sulphonamide had virtually the same gloss. Thus, instead of expensive brightening agents, saccharin can be used to achieve the same gloss in nickel plating. To investigate the stereochemistry of brightener molecules, the density functional theory (DFT) method was used at the computational level of B3LYP with the basis set 6-311G (d,p) ++ in a Gaussian software. The results of computational chemistry showed that the most probable state of adsorption of brightening additives is when the aromatic ring or a double bond or a triple bond of the brightener molecule approaches the cathode surface during the adsorption process. [ABSTRACT FROM AUTHOR]

The hydrogen decrepitation of end-of-life NdFeB magnetic alloys was studied. End-of-life magnets extracted from PC hard drives were taken as a material for the experiments. The choice of these items is governed by their low cost, easy removal from PC, and small size. The magnets were demagnetized at 623 K in a medium vacuum for 4 h, which was followed by three-step cleaning of their surface to remove the electroplated coating, oxidized surface layer, and adsorbed impurities and moisture. The first step of the cleaning was sandblasting with slag shot fed at a pressure of 300 kPa. The second step was chemical etching with solutions of dilute acids (1–3% HCl, HNO3, or H2SO4 in distilled water), followed by washing in acetone. The third step was heat treatment in a vacuum, consisting in rapid heating in a shaft furnace of magnet samples placed after etching in an autoclave, with several exposures in the temperature interval 373–573 K in a medium vacuum. After these operations, the samples were quenched by placing the hot autoclave into a vessel with ice-cold water, preceded by filling the autoclave with argon. Then, alloys of the NdFeB system without removing from the autoclave were subjected to hydrogen decrepitation performed in the temperature interval from 298 to 473 K at an excess hydrogen pressure of 30 to 210 kPa to determine how these parameters influence the properties of the hydride powders obtained and the amount of hydrogen taken up. The hydrogen for the decrepitation was generated by direct desorption from the heated hydride of the LaNi5 alloy. In the pressure range 30–70 kPa and room temperature, alloys of the NdFeB system transform into hydrides. The chemical reaction with hydrogen starts instantaneously without a period of primary hydrogen adsorption. The hydride powders obtained, containing no less than 0.459 wt % hydrogen, are very brittle and can be finely milled (100-g portion) in a planetary ball mill within 6 min to obtain a powder with the particle size smaller than 20 μm. The analysis of the surface of the finely milled hydride powder particles revealed no oxygen (≤1 wt %). [ABSTRACT FROM AUTHOR]

Bacterial biofilms on foreign surfaces are considered a primary cause of implant-related infections, which are challenging to treat. A new implant coating was developed, containing anti-infective silver within a biocompatible polymer carrier substance. In addition to its passive effect on the implant surface, highly concentrated anti-infective silver can be released as needed via the application of high-energy shock waves. This intervention could be applied transcutaneously in a clinical setting without the need for additional surgery. We investigated the inhibition of biofilm formation and the effectiveness of eradication after activation of the coating via shock waves in an in vitro biofilm model using Staphylococcus epidermidis RP62A. This was performed via scanning electron microscopy and quantitative microbiology. Additionally, we examined the cytotoxicity of the new coating on normal human fibroblasts and Saos-2 osteoblast-like cells, depending on the silver concentration. All studies were compared to uncoated titanium surfaces Ti6Al4V and a conventional electroplated silver coating. Cytotoxicity toward normal human fibroblasts and Saos-2 osteoblast-like cells increased with higher silver content but remained tolerable at 6%. Compared to uncoated Ti6Al4V and the electroplated silver coating, the new coating with a silver content of 4% and 6% exhibited a significant reduction in adherent bacteria by a factor of approximately 1000. This was also evident via microscopic examination of the surface morphology of the biofilms. Furthermore, following shock wave activation, no bacteria were detectable on either the implant or in the surrounding fluid after a 24 h period. [ABSTRACT FROM AUTHOR]

The welding process could reduce the performance of the material both microstructure and mechanical strength. Therefore, handling the welding results was necessary. There are several ways to improve the performance of welded joints, namely heat treatment and coating using electroplating. The materials used were galvanized and stainless steel 201 with a size of 100 x 50 x 0.5 mm. Welding used the Metal Inert Gas (MIG) method, while the filler metal used was AWS ER70S-6. The results of the welding were coated by electroplating, while the post-weld heat treatment was carried out to determine the effect of electroplating and heat treatment on the hardness of the joints. There were three temperature variations namely 250 °C, 300 °C, and 350 °C, and three variations of holding time, namely 30 minutes, 60 minutes, and 90 minutes. The highest value of roughness (116.68 VHN) was obtained from a combination of a temperature of 300 °C and a holding time of 30 minutes. While the lowest hardness value (54.93 HVN) was obtained from a temperature of 300 °C with a holding time of 90 minutes. [ABSTRACT FROM AUTHOR]

The integrated sintering of low-temperature co-fired ceramic (LTCC) substrate and silicon-aluminum shell has mature and extensive applications in aerospace T/R module industry. However, it is inevitable to face the reparation of some LTCC substrates due to unqualified properties of the module in practical production. The failure reasons of LTCC substrate were analyzed in this paper. It was advised that the interspace between different LTCC substrates should be 0.1 mm above for the modules with multiple closely-arrayed substrates. It is better to prepare the nickel coating by electroless nickel plating prior to nickel electroplating for silicon-aluminum shells to be repaired, and the thickness of electroplated nickel coating should be more than 2 µm. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Henan University of Science & Technology, Natural Science is the property of Editorial Office of Journal of Henan University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Implant-related infections are a significant concern in orthopedic surgery. A novel anti-infective implant coating made of bioresorbable polymer with silver nitrate was developed. A controlled release of silver ions into the vicinity of the prosthesis can be triggered on-demand by extracorporeal shock waves to effectively combat all clinically relevant microorganisms. Microscopy techniques were used to examine the effects of shock wave application on coated titanium discs. Cytotoxicity was measured using a fibroblast proliferation assay. The anti-infective effect was assessed by monitoring the growth curves of three bacterial strains and by conventional culture. Microscopic analysis confirmed surface disruption of the coatings, with a complete release of silver in the focus area after shock wave application. Spectrometry detected an increase in silver concentration in the surrounding of the discs that surpassed the minimum inhibitory concentration (MIC) for both S. epidermidis RP62A and E. coli ATCC 25922. The released silver demonstrated an anti-infective effect, significantly inhibiting bacterial growth, especially at 6% and 8% silver concentrations. Cytotoxicity testing showed decreasing fibroblast viability with increasing silver concentration in the coating, with 6% silver maintaining viability above 25%. Compared to a commonly used electroplated silver coating on the market, the new coating demonstrated superior antimicrobial efficacy and lower cytotoxicity. [ABSTRACT FROM AUTHOR]

Low carbon steel 1020 AISI has been selected in this study to show the influence of Ni Nano coating on fatigue life of this metal under fatigue loading at room temperature with a stress ratio R= -1. The prepared specimens are exposed to electroplated process using Nano nickel with 40 nm at diverse situations to improve the fatigue limit of metal. (SCHENCK PUNN) rotating bending fatigue test, hardness, tensile strength, microstructure, surface roughness and SEM, XRD diffraction tests have been completed for base metal and electroplating treated metal. The experimental results indicate that Ni nano coating by electroplating improve the fatigue life at due to steel substrates are typically polished mechanically and chemically before deposition to enhance the fatigue properties and nano nickel have fair distribution on steel surface. [ABSTRACT FROM AUTHOR]

The properties of hot‐dip galvanised and electroplated zinc coatings on steel have been widely studied, but the corrosion mechanisms of zinc flake coatings have not yet been investigated in similar detail. Here, we investigate the protective effect of inorganic lamellar zinc coatings, comparing the metallic dissolution rates of different zinc, aluminium and alloyed flakes using an inductively coupled plasma mass spectrometry (ICP‐MS) flow cell. These experiments were carried out on both intact and predamaged coatings with different electrolytes. Data were also compared to accelerated laboratory corrosion tests and outdoor weathering results. The chloride concentration, and its effect on the passive oxide film, appears to be a key aspect moderating the dissolution rate and hence sacrificial zinc dissolution under various conditions. The complementary use of accelerated tests and ICP‐MS flow cell analysis provides new insights into both the influence of the corrosive environment and the impact of the zinc flake (alloy) used. Based on this approach, tailored coating solutions using zinc flake coatings can be developed. [ABSTRACT FROM AUTHOR]

A cyanide-free copper(I)-based bath for direct electroplating on steel substrate was developed. The effect of thiourea as complexing agent on the electrodeposition of copper(I) ion was studied electrochemically. The adhesion, surface morphology, elemental composition, and phase structure of the electroplated copper coating were characterized by cross-cut testing, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD), respectively. The results showed that thiourea could form a stable complex with Cu(I) ion, resulting in a much more negative deposition potential of Cu(I) ion, and avoiding the displacement reaction between copper and iron when conducting the electrodeposition of copper directly on steel substrate. The given bath had a wide range of working current density at a temperature not lower than 60 °C. Both cathodic and anodic current efficiencies of the bath are higher than 95%. A smooth, compact, fine-grained, highly pure, and well-adhered copper coating could be electrodeposited directly on steel in the given bath. [ABSTRACT FROM AUTHOR]

The spindle is the key working part of the horizontal cotton picker, and the wear resistance of its surface directly affects the service life of the spindle. Improving the surface performance of the spindle is fundamental for improving the performance of cotton pickers. To enhance the wear resistance of the spindle surface, this study used the physical vapor deposition (PVD) technique to prepare TiN coating on the spindle substrate surface of the cotton-picking machine to improve the spindle surface rather than the original electroplated chromium coating. The microscopic morphology of the spindle was analyzed by scanning electron microscope (SEM), the mechanical and frictional properties of the spindle were tested by a nanoindentation tester and a friction wear tester, and the morphology of the worn spindle was observed by a portable microscope and a 3D surface profiler. The test results indicated that after the PVD treatment, the surface hardness of the spindle was about 2.5 times that of the electroplated chromium spindle, and the H/E value was 2.2 times that of the electroplated chromium spindle. PVD-TiN spindle showed better mechanical properties. In the friction test, under the same conditions, the wear rate of the PVD-TiN spindle was less than that of the chrome plating spindle. In a field test of 100 hm2, the average wear area of the second tooth tip surface of the electroplated chromium spindle was about 2.17 times that of the PVD-TiN spindle. It was verified that the PVD-TiN spindle surface had better wear resistance than the electroplated chromium spindle. This study has certain research significance for the performance optimization of cotton pickers. Also, it is indicated that PVD-TiN coating can effectively improve the wear resistance of the spindle surface and provides a new method for enhancing the service life of the spindle. [ABSTRACT FROM AUTHOR]

This work deals with the development of cyanide-free copper-silver electroplated coatings on AISI-1075 steel and its corrosion behavior under a 5% NaClO solution (commercial household bleach). A cyanide-free bath based on sodium thiosulfate was employed to obtain the silver coatings using current densities from 0.2 to 5.0 mA/cm2 and different concentrations of EDTA (additive). The evolution of the open circuit potential with time showed that silver is anodic with respect to copper, so there were no intense attacks in the silver pores. Adhesion measurements were made on both coatings by the tape test. The behavior against corrosion was evaluated by polarization resistance (Rp) in samples with the best coating adhesion. The best results were obtained with a silver coating of about 20 μm in thickness deposited on copper coating previously polished with colloidal silica. The best performance was attributed to the formation of AgCl as demonstrated by x-ray diffraction and scanning electron microscopy. [ABSTRACT FROM AUTHOR]

Copyright of Electroplating & Finishing is the property of Electroplating & Finishing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electroplating & Finishing is the property of Electroplating & Finishing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Due to its unique physical and chemical properties, bismuth is an attractive candidate for a wide range of applications such as battery anodes, radiation shielding, and semiconductors, to name a few. This work presents the electrodeposition of mechanically stable and homogenous bismuth films at micron-scale thicknesses. A simple one-step electrodeposition process using either a pulse/reverse or direct current source yielded thick, homogenous, and mechanically stable bismuth films. Morphology, electrochemical behavior, adhesion, and mechanical stability of bismuth coatings plated with varying parameters were characterized via optical profilometry, cyclic voltammetry, electron microscopy, and tribology. Scratch testing on thick electroplated coatings (> 100 µm) revealed similar wear resistance properties between the pulse/reverse plated and direct current electroplated films. This study presents a versatile bismuth electroplating process with the possibility to replace lead in radiation shields with an inexpensive, non-toxic metal, or to make industrially relevant electrocatalytic devices. [ABSTRACT FROM AUTHOR]

Electroplating nanocrystallite Ni coating can improve the mechanical properties of the metal structure surface, which is widely used in fabricating metal MEMS devices. Because of the large internal compressive stress caused by the oxidation layer of the substrate surface, the Ni coating easily falls off from the substrate surface. To solve this bonding problem, the ultrasonic assisted electrochemical potential activation method was applied. The ultrasonic experiments have been carried out. The bonding strength was measured by the indentation method. The substrate surface oxygen element was tested by the X-ray photoelectron spectroscopy (XPS) method. The dislocation was observed by the TEM method. The compressive stress was tested by the XRD method. The coating surface roughness Ra was investigated by the contact profilometer method. The results indicated that the ultrasonic activation method can remove the oxygen content of the substrate surface and reduce the dislocation density of the electroplating Ni coating. Then, the compressive stress of the electroplated Ni coating has been reduced and the bonding strength has been improved. From the viewpoint of the compressive stress caused by the oxygen element of the substrate surface, mechanisms of the ultrasonic activation method to improve the bonding strength were researched originally. This work may contribute to enhancing the interfacial bonding strength of metal MEMS devices. [ABSTRACT FROM AUTHOR]

• Performance characterization of electroplated chromium coating during dry friction process. • Surface crack propagation evolution process of electroplated chromium coating. • Mechanical analysis of surface crack propagation. Electroplated chromium coatings are commonly used to improve the wear resistance of metal parts in the cotton textile industry, and surface crack is an important feature. This study investigates the tribological properties and surface crack propagation of the electroplated chromium coating in dry friction contact with cotton fabric. It is found that the coating has excellent tribological properties, with the friction coefficient eventually stabilized at 0.11 and the average wear rate of 0.0038 mm3/h. The cotton fabric mainly exhibits a polishing effect on the coating during friction, and the failure of the coating is in the form of delamination failure within the coating. Crack propagation is mainly due to the friction of cotton fabric, the main cracks of the mesh crack structure hardly propagate, while the short cracks extending on the main cracks undergo propagation behavior. Short cracks propagate vertically along the friction direction and eventually develop into the main crack level. The tangential stress generated by friction acts on the crack tip, which is the main cause of crack propagation. The plastic zone generated at the crack tip affects the distribution of the stress field and the effect of the plastic zone on crack propagation is analyzed. [ABSTRACT FROM AUTHOR]

Herein, the effect of heat treatment on the high‐temperature wear resistance of Ni–Co electroplating coating on copper surface is systematically investigated. Results show that the oxide layer formed on the surface of coating during heat treatment induces the wear mechanism transition of coating. Under the condition without oxide layer formation (heat treatment at 400 °C), the coating suffers severe adhesive wear due to the low hardness caused by grain growth. After heat treatment at 600 °C, the formation of CoO and Co3O4 oxide layers on the surface of coating improves wear resistance, and the wear mechanism changes to oxidative wear and adhesive wear. The density of the oxide layer determines the degree of adhesive wear. As the heat treatment temperature increases (900 °C), the formation of a denser NiCo2O4 oxide layer with higher hardness further inhibits the adhesive wear mechanism of the coating. Until more than 6 h, the formation of scale‐shaped NiCo2O4 and 3CoO·NiO oxide layers significantly improves the wear resistance of the coating and completely eliminates adhesive wear. The wear mechanism is transformed into oxidative wear. [ABSTRACT FROM AUTHOR]

Utilising microphones as audible sound sensors for monitoring a single-side grinding process with lapping kinematics is presented in the paper. The audible sound generated during grinding depended on the cutting properties of electroplated tools with D107 diamond grains and different thicknesses of the nickel bond. The tool wear affected the obtained technological effects such as material removal rate and the surface roughness of Al2O3 ceramic samples. The relationship between the quantities that characterise the sound signal and the surface roughness of machined surfaces was examined with the use of spectral analysis of the sound signal in the frequency domain with a focus on the Ra parameter. The decreasing amplitude indicated a better surface finish, down to Ra = 0.23 µm. The developed method and the obtained results will facilitate the practical use of the electroplated tools in the lap-grinding technology without interrupting the process before obtaining the required surface roughness. [ABSTRACT FROM AUTHOR]

In the current research work, NiMo thin films were successfully co-deposited with W on the copper substrate (NiMoW) by varying the plating times like 30, 45, and 60 min at a constant current density (50 mA/cm2). All the electroplated NiMoW thin films have been subjected to structural (SEM–EDS and XRD), mechanical (hardness, roughness, and corrosion), and magnetic (VSM) characterization analysis. The existence of a perfect nanocrystalline phase in the coated NiMoW thin films was found through XRD, and the average crystalline size varied from 33 to 37 nm. All the coated NiMoW thin films have a cubic (FCC) crystalline structure with an Fm-3m (225) space group. The obtained SEM–EDS result discloses that the synthesized NiMoW thin films have uniform surface morphology with spherically shaped nanoclusters, and the film deposited at 60 min has the maximum nickel content as compared with coatings at 30 min which in turn enhance the corrosion resistance and magnetic nature of NiMoW coatings and also reveals the NiMoW thin films coated at 30 and 45 min have almost equal W and Mo content. The thickness of synthesized NiMoW thin films was found to be varied from 5 to 15 µm using Metallurgical Microscope (OIAL/MMN/MET/01). The coatings were found to be strongly adherent with a substrate (Cu) and the NiMoW coatings at 60 min exhibited the highest hardness value of 293 VHN. The electrochemical studies of NiMoW thin films explored that the coatings synthesized at 60 min exhibited the highest corrosion resistance value of 635.18 K Ω (low corrosion rate of 0.6861 mm/year). All the electroplated NiMoW coatings have an average roughness (Ra) value of around 185 nm, and the roughness values were calculated using a profilometer. The magnetic investigation on NiMoW thin layers through VSM shows that the coatings at 60 min exhibited the nanocrystalline soft ferromagnetic nature with a lower coercivity of 106.94 Oe and saturation magnetization of 925.80 × 10–6 emu. The analysis concluded that the NiMoW thin films coated at 60 min exhibited better mechanical and magnetic properties than coatings at 30 and 45 min of deposition time. [ABSTRACT FROM AUTHOR]

Electroplating is one of the most common methods for applying electronic connector coatings. This research investigated the tribological behavior of electroplated multilayer coatings of Sn, Ni, and Cu with and without intermetallic compound layers (IMC), which are intermediate compounds formed between two metals under reciprocating sliding. It is found that heat treatment promotes both Sn/Ni IMC and Sn/Cu IMC growth. Based on the test results, the tribological performance of all heat‐treated samples is enhanced due to the high hardness of the IMC. The existence of the Ni layer slows the formation of IMC between the Sn and Cu coatings, but it is not producing a significant improvement from the perspective of tribological performance. [ABSTRACT FROM AUTHOR]

In cases of severe bone tissue injuries, the use of metallic bioimplants is quite widespread due to their high strength, high fracture toughness, hardness, and corrosion resistance. However, they lack adequate biocompatibility and show poor metal-tissue integration during the post-operative phase. To mitigate this drawback, it is beneficial to add a biocompatible polymer layer to ensure a quick growth of cell or tissue over the surface of metallic bioimplant material. Furthermore, this additional layer should possess good adherence with the underlying material and also accompany a rapid bonding between the tissue and the implant material, in order to reduce the recovery time for the patient. Therefore, in this work, we report a novel green electroplating route for growing porous hydroxyapatite-brushite coatings on a stainless steel surface. The malic acid used for the production of hydroxyapatite-brushite coatings has been obtained from an extract of locally available apple fruit (Malus domestica). We demonstrate the effect of electroplating parameters on the structural morphology of the electroplated composite layer via XRD, SEM with EDS, and FTIR characterization techniques and report an optimized set of electroplating parameters that will yield the best composite coating in terms of thickness, adherence to substrate and speed. The hemocompatibility and osteocompatibility studies on the electroplated composites coating show this technology's effectiveness and potential applicability in biomedical applications. Compared to other routes reported in the literature, this electroplating route is quicker and yields better composite coatings with faster bone tissue growth potential. [ABSTRACT FROM AUTHOR]

• Pulse reverse (PR) electroplating creates crack-free Cr coatings. • PR electroplated Cr coatings exhibit enhanced diffusion barrier resistance. • Optimized PR process improved high-temperature stability of Cr coating microstructure. • Novel solution to hydrogen-induced microcracks in Cr coatings is proposed. Fuel cladding chemical interaction (FCCI) is a critical issue affecting the safe usage of metallic nuclear fuel in sodium-cooled fast reactors (SFRs). Although a chromium (Cr) coating diffusion barrier has been developed to effectively mitigate FCCI, Cr coatings formed by direct current (DC) and pulse current (PC) electroplating generate hydrogen-induced micro-cracks that reduce diffusion barrier performance. In this study, electroplating with a pulse reverse (PR) current and optimized anodic time was utilized to minimize the effects of hydrogen. Consequently, this approach enabled the formation of a crack-free and highly stable microstructure in the electroplated Cr coating. A diffusion couple test (FCCI test) was conducted at 923 K for 25 h to evaluate that the diffusion barrier performance of the Cr coating formed by DC, PC and PR electroplating. The test results demonstrate the superior diffusion barrier performance of the Cr coating formed by PR electroplating through a systematic analysis comparing the microstructures of Cr coatings formed by different waveforms. [ABSTRACT FROM AUTHOR]

A mixed metal oxide-coated Ti felt was constructed for use as a porous transport layer (PTL) in a proton exchange membrane (PEM) water electrolyzer. The PTL was fabricated by coating Ti felt with 0.43 mg TaOx cm−2 and 1 mg Ir + Ru cm−2 IrO 2 –RuO 2 -TaO x using a thermal decomposition method. The coated Ti felts exhibited high conductivity, mass transport performance, stability and oxygen evolution reaction (OER) catalytic activities. The stability of IrO 2 –RuO 2 -TaO x coating obviously improved than traditional electroplated Pt coating. Using the PTL, a single cell performance of 1.836 V @ 2000 mA cm−2 was achieved at 80 °C under ambient pressure with 1 mg cm−2 of precious metal in anode CL. However, the precious metal loading is about 2 mg cm−2 in common PEM electrolyzer anode catalyst layer (CL). The IrO 2 –RuO 2 -TaO x -coated Ti felt proved to be a promising low-cost PTL for PEM water electrolysis with high performance. • The TaOx improved the stability of IrO 2 –RuO 2 -TaO x coating as PTL. • The IrO 2 –RuO 2 -TaO x coated Ti felt as PTL showed great performance in PEM electrolyzer. • With IrO 2 –RuO 2 -TaO x coating, a single cell performance of 1.836 V @ 2 A cm−2 was achieved with 1 mg cm−2 Ir in anode CL. [ABSTRACT FROM AUTHOR]

Copyright of Electroplating & Finishing is the property of Electroplating & Finishing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To improve the heat transfer performance (HTP) of stainless steel, the micro-nano concave chromium (Cr) coating was fabricated on the surface of 304 stainless steel by the combination technology of electrodeposition and anodic oxidation. The effects of electroplating and anodizing time on the morphology, contact angle (CA) and heat transfer coefficient (HTC) of the coating were studied. The results show that the samples with large surface area and good wettability have higher HTC. Besides, the Cr coating obtained after 2 h electroplating has silver white appearance, smooth surface and a thickness of about 37 μm. The 2-h electroplated Cr coating after anodizing for 30 min presents a concave pore structure with a pore diameter of 7.4 μm and the best wettability (a CA of 41.8°), which is 20° lower than that of the stainless steel substrate. The two-phase heat transfer efficiency of the sample with the concave Cr coating was increased by 22.84 % when the fluid mass flux is 33.3 kg m−2 s−1 and the inlet temperature is 40 °C and the fluctuations of pressure drop in the micro-channel was effectively reduced. The enhanced HTP of concave Cr coating is owing to the larger specific surface area and better wettability caused by the unique rough concave structure. [ABSTRACT FROM AUTHOR]

Copyright of Electroplating & Finishing is the property of Electroplating & Finishing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copper (Cu) has been successfully cold spray deposited on carbon fiber-reinforced polymer (CFRP) by a hybrid fabrication process. In this present study, the feasibility of Cu coating build-up on a Cu electroplated CFRP under a process with two-step gas pressures was investigated numerically and experimentally. The deformation and deposition behavior of the Cu particles on CFRPs coated with tin (Sn), nickel (Ni), and Cu were studied by comparing the single-particle impact with thick coating fabrication. The deposition efficiency (DE) of the cold-sprayed coatings was measured, and the microstructure and microhardness of the coatings were evaluated. The results showed that Cu coating build-up was possible with lower DE in the second spray pass of the cold spray system compared to that of the first fabricated cold-sprayed layer. This is due to the higher hardness of the previously cold-sprayed layer as compared to the electroplated Cu coating. Cold spray deposition of Cu on soft Sn and hard Ni interlayers was not feasible due to substrate erosion and insufficient plastic deformation of the substrate, respectively. From single particle impact deposition and thick coating fabrication, it was found that successful deposition in low-pressure cold spraying only takes place in the case of co-deformation phenomenon, where the substrate and the particle have nearly equal hardnesses. These results suggest that the relative hardness of the substrate to the particle significantly affects the particle deformation behavior and DE of the cold sprayed coating. [ABSTRACT FROM AUTHOR]

In cases of severe bone tissue injuries, the use of metallic bioimplants is quite widespread due to their high strength, high fracture toughness, hardness, and corrosion resistance. However, they lack adequate biocompatibility and show poor metal-tissue integration during the post-operative phase. To mitigate this drawback, it is beneficial to add a biocompatible polymer layer to ensure a quick growth of cell or tissue over the surface of metallic bioimplant material. Furthermore, this additional layer should possess good adherence with the underlying material and also accompany a rapid bonding between the tissue and the implant material, in order to reduce the recovery time for the patient. Therefore, in this work, we report a novel green electroplating route for growing porous hydroxyapatite-brushite coatings on a stainless steel surface. The malic acid used for the production of hydroxyapatite-brushite coatings has been obtained from an extract of locally available apple fruit (Malus domestica). We demonstrate the effect of electroplating parameters on the structural morphology of the electroplated composite layer via XRD, SEM with EDS, and FTIR characterization techniques and report an optimized set of electroplating parameters that will yield the best composite coating in terms of thickness, adherence to substrate and speed. The hemocompatibility and osteocompatibility studies on the electroplated composites coating show this technology's effectiveness and potential applicability in biomedical applications. Compared to other routes reported in the literature, this electroplating route is quicker and yields better composite coatings with faster bone tissue growth potential. [ABSTRACT FROM AUTHOR]

The choice of the electroplating conditions of Ni-based alloys has always been a serious research question. In this study, an artificial neural network based on central composite design modelization were used to determine the desired percentage of Ni and the optimum thickness of the coating before passing to the implementation of the work. Three main factors were found to be very important in this process; namely applied current density (I), pH of the bath and the temperature (T) during electrolysis. The optimum conditions generated by the mathematical model proposed in this work were 42 mA cm−2, pH 4.5 and 50 °C for the Ni-alloys (Zn, Co, Cr and W). Theoretically, the optimum amount of Ni and the thickness of the alloy were 40% and 23 µm, respectively. The SEM images indicated that the optimum (I) would yield homogenous and compact morphologies. Moreover, the XPS investigations revealed that the optimum pH would form a strong Ni bond. Finally, the XRD analysis showed that the optimum T would result in a stable Ni-alloy crystallinity for Zn, Co and Cr. In contrast, Ni-W alloys showed that the amorphous phases were more stable. [ABSTRACT FROM AUTHOR]

Cr-C coatings were obtained from two different Cr(III)-baths based on sulphate and chloride salts, respectively. A tailored characterization was carried out by scanning electron microscopy, several spectroscopies and Mott-Schottky approaches (including Point Defect Model) to find out the impact in the corrosion performance of the morphology, composition, and semiconducting properties of the native oxide layers. The polarisation curves using 0.01 M NaCl have shown better corrosion resistance capabilities for the chloride-based Cr(III) coatings which is in agreement with the lower crystal size and the less defective native oxide layer (using a borate buffer electrolyte). [ABSTRACT FROM AUTHOR]

Quantitative characterization of tensile stress in electroplated nickel coatings on the copper substrate with the thickness range of 2.809 µm to 35.654 µm in the elastic stage was experimentally performed with a magnetic incremental permeability (MIP) sensor in the study. Firstly, a differential mutual-inductance sensor based on the parallel excitation of bifilar co-directional coil was proposed. With the proposed sensor, multiple signals including high-frequency eddy current (HFEC), tangential magnetic field strength, and magnetic incremental permeability butterfly curve (MIPBC) could be measured synchronously and eight typical magnetic parameters were obtained from experimental signals. Then, four parameters including the peak height of MIPBC, amplitude at cross point of MIPBC, difference frequency of HFEC, and sum frequency component of HFEC were selected to quantitatively characterize tensile stress. Experimental results showed that the four parameters depended on tensile stress and showed a parabolic trend. The parameters of the parabolic equation varied with nickel coating thickness. Finally, a polynomial surface fitting method based on the combination of the factors of thickness and tensile stress were derived with the selected four parameters and the coefficient of determination R 2 was higher than 0.9. The further comparison between theoretical results and predicted stress confirmed that the proposed MIP sensor could realize the quantitative detection of tensile stress in different nickel coatings. [Display omitted] • A multi-functional MIP sensor, with the ability of several magnetic signal measurement, was developed. • The multi-functional MIP sensor not only suppresses mutual inductance signals, but also provides compact structure. • MIP sensor accurately predicts tensile stress in electroplated nickel specimen, accounting for variations in specimen thickness. [ABSTRACT FROM AUTHOR]

In pursuit of sustainable hydrogen production, alkaline water electrolysis offers fossil-free technology for generating hydrogen. Exploring new non-precious metal electrocatalysts plays a crucial role in this endeavor. Herein, we investigate a trimetallic NiFeMo material on a nickel foam support, serving as a bifunctional electrocatalyst for catalyzing both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Scanning electron microscopy reveals a nanosheet array structure with a uniform distribution of Ni, Fe, and Mo compounds on the electrode surface. Furthermore, the chemical surface composition of the pristine and spent electrodes is elucidated via x-ray photoelectron spectroscopy, displaying primarily oxidized species on the electrocatalyst surface. Bifunctional performance is assessed in a three-electrode setup, unveiling overpotentials of 70 mV for the HER and 140 mV for the OER, in a 30 wt% KOH electrolyte at 90 °C. Additionally, in an industrial electrolysis cell, the activated electrode is evaluated as cathode and anode for 28 days, which decreased the overpotential of 330–350 mV at 200 mA cm geo −2 compared with pristine nickel foam. The performance increase of the electroplated coating is attributed to the increased surface area and enhanced intrinsic activity. The electrolysis cell experiences a ∼6 % voltage loss during the experiment, indicating its robustness and suitability for industrial alkaline electrolysis applications. [ABSTRACT FROM AUTHOR]

A new strategy for preparing TaC coatings on easily oxidized tantalum by non-vacuum carburizing is proposed, which is called Fe-coating-mediated carburization. Fe-coating-mediated carburization is the carburization of Ta substrate with a pre-electroplated Fe coating. During carburization, the electroplated Fe coating was transformed into a carbon steel coating, while a high concentration of interstitial carbon atoms in the carbon steel coating diffused into tantalum, forming a TaC coating. The Fe coating isolated the tantalum from oxygen and changed the state of active carbon atoms in contact with the tantalum surface. The TaC coatings are nonporous, have fine grains with grain size gradients, and combine high hardness (32 GPa) and excellent coating-substrate adhesion strength (>100 N). The Fe-coating-mediated carburization realizes the carburization of oxidizable carbide-forming metals under non-vacuum conditions, providing a new strategy to prepare protective coatings with both high hardness and high coating-substrate adhesion for carbide-forming metals. • A surface hardening method called Fe-coating-mediated carburization is proposed. • Non-vacuum carburization of easily oxidized tantalum is realized. • The coating is nonporous and has a gradient microstructure with fine TaC grains. • The hardness reaches 32 GPa and the adhesion strength exceeds 100 N. • The function of the Fe coating and the advantages of this method are elucidated. [ABSTRACT FROM AUTHOR]

Copyright of Electroplating & Finishing is the property of Electroplating & Finishing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article studies the effect of macro- and microdistribution factors on the uniformity of electroplated copper coatings in through-holes of printed circuit boards. A computer program has been developed for simulating the primary potential distribution field and for calculating the local current densities for a two-dimensional model of electrodes with arbitrary shapes and mutual arrangement. The cross-sectional profile of a through-hole with a channel width equal to the hole diameter was taken as the two-dimensional model. A calculation of the primary potential distribution field predicts that the current density in wide through-holes decreases significantly and electroplating in narrow holes is nearly blocked. As the diameter of a through-hole decreases, the macrothrowing ability decreases in accordance with the decrease in the Wagner number, while the nonuniformity of the copper deposit thickness inside the holes increases, as confirmed by micrographs of cross sections of samples obtained in the electrolyte with and without a set of additives. The latter comprised leveling agents based on polyalkylene glycols and nitrogen-containing heterocyclic compounds, along with brightening organic sulfur-containing additives. Analysis of data on the distribution of copper on the cross sections of samples treated in stagnant electrolytes and with stirring, other conditions being equal, reveals a significant effect of uneven microdistribution in narrow holes. Addition of the set of leveling and brightening compounds to the electrolyte provides a small positive leveling power, which makes it possible to obtain uniform smooth coatings without a local thickness decrease at the orifice. The noticeable increase in the copper layer thickness in the middle of narrow holes in the presence of additives observed under conditions of diffusion limitations cannot be explained solely in terms of the effect of primary and secondary distribution. The effect of the increase in d1/2 may be due to the depolarizing effect of the brightening sulfur-containing components of additives inside the holes. [ABSTRACT FROM AUTHOR]

Rhenium was the most interesting material because it can be oxidized at high temperatures, so it is a promising applicant in biomedical applications. Its high melting point requires techniques such as electro-coating to produce it in thin-film formation, using a current of 40 mA/cm2, in a cathode pulse and 4 mA/cm2, in anodic form, the variation in temperature of the acid electrolytic bath being realized in a range of 60 to 85±2 °C. The temperature variation of the samples allowed to correlate their response to the degradation phenomenon. The topographical evaluation using atomic force microscopy on the surface of the samples permitted to indicate that a tendency of the roughness to reduce with the increase of the temperature up to 80 °C existed, an electrochemical evaluation was generated using Tafel polarization curves, immersed in a Ringer's lactate solution with a temperature of 37 °C, has now been subsequently performed using the scanning electron microscope, the surface analysis of the coatings, demonstrating that at deterioration is negligible, but when increasing the temperature to 80 °C, the deterioration is imperceptible when the type of surface damage is unobservable, however in the case of 85 °C the deterioration is observable. [ABSTRACT FROM AUTHOR]

The corrosion rates of Ni-W, Co-W, Ni-Mo, and Co-Mo electrodeposited coatings after two-hour immersion tests in HNO3, H2SO4 and HCl environments were studied by the weight loss method. The best corrosion resistance was revealed for Ni-W alloy, and the worst for Co-Mo. For all tested samples (36 in total), the maximal corrosion rate was observed in nitric acid, and the minimal one, with an exception of Ni-W, in hydrochloric acid. It was found that for the W-containing coatings corrosion evenly affected each individual crystallite of the alloy structure changing its shape and volume, and the corrosion of Mo alloy-based coatings showed mixed character. According to the Pourbaix diagram, for Mo alloys (Ni-Mo and Co-Mo) the lower corrosion resistance compared to the coatings containing W can be explained by a narrower region of MoO3 formation, as well as by their higher solubility in comparison with WO3. [ABSTRACT FROM AUTHOR]

Copyright of Electroplating & Finishing is the property of Electroplating & Finishing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The design, fabrication, and testing of a microelectrode array for chronic in vivo stimulation of the rat retina is presented. Epiretinal positioning of the array introduced design challenges associated with the surgical implantation approach into the rat ocular orbit. These anatomical and surgical challenges were overcome using microfabrication of thin-film Parylene C and platinum to create the array followed by thermal post-processing steps to achieve the required array geometry. An electroplated platinum-iridium coating was employed to increase the electrode charge storage capacity and then verified in benchtop electrochemical characterization. Preliminary in vivo implantations with sham devices containing no metal revealed chronic biocompatibility (up to 6 weeks) and acute trials with functional arrays illustrated device robustness against surgical trauma. This work represents the first epiretinal implant development for the rat animal model via a suitable soft neural interface device enabled through polymer MEMS micromachining. [ABSTRACT FROM AUTHOR]

Copyright of Electroplating & Finishing is the property of Electroplating & Finishing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A highly reliable neural interface is required in long-term neural signal recording in vivo for neuroscience research and the treatment of neurological disorders. Organic poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) is a promising candidate for a next-generation neural interface material due to its better faradaic charge transfer and capacitive charge coupling than metal electrodes such as Au or Pt. However, its weak adhesion to underlying metallic layers impedes its application with significant cracks or delamination. Here, a MEMS-compatible strategy is proposed to obtain wrinkled microelectrodes based on oil-pretreated elastomer substrate to improve the electrochemical performance and stability of electroplated PEDOT:PSS coating. To discover the optimized electroplating parameters, the galvanostatic electroplating method is applied with incremental time from 0 to 500 s. The modified wrinkled microelectrodes with electroplating time of 300 s permits 10 000 cyclic voltammetry scanning cycles without cracks nor significant change in charge storage capacity or electrochemical impedance, whereas the cracks and delamination appear when the electroplating time increases to 500 s. [ABSTRACT FROM AUTHOR]

Various methods of surface preparation for electroplating on aluminum alloys are considered. It was shown that the most suitable of them is electrochemical anodizing. The composition and operating mode of the anodizing electrolyte were developed. The effect of the electrolyte composition on the structure and the film surface development is shown. The stability of the oxide film produced as a result of anodizing to dissolution in copper and nickel plating electrolytes was demonstrated. The relationship between the adhesion of electroplated coatings to an aluminum substrate with the relief and uniformity of oxide films was established. The proposed pretreatment is universal and can be used for any aluminum alloys in modern automatic lines without breaking the technological process chain. [ABSTRACT FROM AUTHOR]

This study reports about the influence of the microstructure of electroplated Zn–Ni alloy coatings, especially the extent and characteristic of existing microcracks within, on hydrogen effusion characteristics at room temperature (RT) and 200 °C. For comparison, the behavior of an electroplated Zn coating was also investigated. The microstructures of the Zn and Zn–Ni coatings were examined by means of scanning electron microscope (SEM) and optical microscope (OM). These results were correlated with the hydrogen effusion profiles, which were determined by using a carrier gas hot extraction (CGHE) technique. In addition, a silver decoration method was applied to visualize the hydrogen effusion paths within the coatings. First both Zn–Ni electroplating processes exhibit less hydrogen absorption compared to Zn. In addition the microstructure of the Zn–Ni coatings, especially the characteristic and magnitude of the microcracks, significantly influences the hydrogen effusion characteristics. By using the silver decoration method according to (Schober in MTA 14:2440-2442, 1983) it could be proofed that for Zn–Ni hydrogen primary effuses along the microcracks and the interfaces of pustules within the coating. But the microcracks seem to promote the hydrogen effusion much more than the interfaces of the pustules. [ABSTRACT FROM AUTHOR]