Ni Plating Research Articles

Characterization of the Contamination Factor of Electroless Ni Plating Solutions on the ENIG Process

The electroless nickel immersion gold process often produces defects, such as pinholes and black pads that can cause brittle fractures at the interface between the solder and metal pad. Contamination in electroless Ni plating solutions with increasing metal turn over (MTO) is believed to be one of the causes of the formation of surface defects. MTO means indirectly Ni bath life, with ‘‘0 MTO’’ indicating a freshly plating bath and ‘‘2 MTO’’ an aged plating bath, which is supplemented twice with the initial amount of metallic salts and the reducing agent. In this study, surface defects on the Ni-plated layer were investigated to understand the correlation between the MTO solutions and defect factors by solder resist (SR) dissolution. The characteristics of the contaminated MTO solutions were analyzed by total organic carbon and liquid chromatography mass spectrometry (LC-MS). LC-MS detected the component (melamine) of the hardener of the SR at 2.14 ppm in the 2 MTO, and 2.52 ppm in the 2.5 MTO solutions. Electroless nickel plating was conducted in a 0 MTO solution with hardener addition. Pinholes were observed in solutions containing more than 2 ppm of a hardener. In particular, the content of phosphorus in the defective area was higher than that in the non-defective area. Consequently, as the MTO solution increased, the hardener was dissolved in the Ni solution, which caused defects in the nickel surface layer, such as pinholes and black pads.

Nickel electroplating on copper pre-activated Al alloy in the electrolyte containing PEG1000 as an additive

Ni coatings are prepared on Cu-pretreated anodic Al alloy by electroplating technique in environment-friendly electrolytes with PEG1000 as an additive. Some defects like pores, cracks and even uncovered areas are observed for the sample of the Cu-pretreated anodic Al alloy, and these defects seem to be remedied with the following Ni electroplating as observed from their SEM images; while the covering effect of Ni onto the Cu layer is rather limited as judged by their corrosion current data of polarization test. After adding PEG1000 in the Ni electroplating electrolyte, the obtained coating surfaces are seen smoother and thicker; and most of the tiny particles are seen closely packed together with some bigger particles on them. The diffusion of nickel particles into copper layer are confirmed by the line and mapping mode of EDS element analysis for the Ni–Cu composite coating. Their much lower corrosion current density (Icorr) and higher micro-hardness support the fact that the addition of PEG1000 in Ni plating electrolyte has a function of promoting the refinement of Ni particles and the formation of more compacter, thicker and smoother Ni–Cu composite coating.

Wetting and brazing of Ni-coated WC–8Co cemented carbide using the Cu–19Ni–5Al alloy as the filler metal: Microstructural evolution and joint mechanical properties

Abstract

Identification of nickel emission lines using Nd:YAG laserinduced breakdown spectroscopy

Identification of nickel element (Ni) is necessary in various fields including agriculture, mining, and industries. In this study, rapid identification of nickel metal in was made by using laser-induced plasma spectroscopy method. Experimentally, a pulse laser beam (Nd:YAG laser, 1064 nm) was focused on a sample target to initiate a plasma. The plasma emission was detected by optical multichannel analyzer system to obtain the emission spectrum from the sample target. The target used was pure nickel metal plate and Indonesian currency coin containing Ni. The results show that the Ni lines can clearly be detected from the Ni plate at the wavelengths of neutral Nickel (Ni I) at wavelength of300.363, 305.432, 310.188, 313.411, 341.348, 345.289, 351.977, 356.637, 351.977, 356.637, 361.939, and 778.894 nm for neutral Ni lines and at the wavelength of 337.897 nm for ionic Ni line. It was also demonstrated that the Ni emission lines at the same wavelength in the Ni metal plate was also detected from the other sample of currency coin containing Ni. This certified that the present can be used to identify Ni emission in metal sample containing Ni.

Hydrogen Bubble Templating of Fractal Ni Foams for Water Oxidation in Alkaline Media

Dynamic Hydrogen Bubble Templating of Ni electrodes (NiDHBT) is applied to form fractal macroporous structures and their properties towards oxygen evolution reaction (OER) is assessed. Upon varying Ni electrodeposition conditions, morphological features with percolating porosity were finely tuned and electrochemical activity towards O2 evolution reaction (OER) in 1M KOH were enhanced. As demonstrated by cyclic voltammetry, NiDHBT electrochemical features displayed a tremendous increase (x 250) of the electrochemically active Ni surface atoms, with strong mechanical adherence to the underlying substrate. Under constant electrolysis (0.25 A cm-2), OER potentials remained stable and occurred at lower potentials (shifted by ca. 300 mV) as compared to a bare Ni plate. Contact angle measurements confirm the super-aerophobic nature of the fractal Ni films, which leads to fast and sustainable release of O2 bubbles during potentiostatic measurements. Due to the versatility of the DHBT method, fractal Ni-based, e.g. NixFe1-x, electrodes for use in advanced electrolysis cell configurations can be envisioned, to further examine transport enhancement in relevant industrial systems and its tolerance to commercial alkaline solutions.

THICKNESS DETERMINATION AND CONTROL OF FUNCTIONAL Ni–COMPOSITE ELECTRODEPOSITED COATINGS

Surface electrochemically plated with nickel and highly inert particles provides useful applications: Ni–CeO2 as chemical catalysts, high hardness Ni–CBN (cubic boron nitride) as grinding tools, among others. The plating’s inert particles – 100 mm in size – on nickel surface need to be tightly adherent and evenly dispersed; it is therefore necessary to determine and control the coating layer’s thickness corresponding to the inert particles’ size by parameters like electrical current density and time. With 40–60 nm CeO2 particle size, Ni plating thickness is 12 mm. With 60–100 mm CBN particles, Ni plating thickness is up to 60 mm. Weight and plating thickness were determined by the weight method and Faraday's law. The difference between the two methods showed the presence of inert functional particles on composite coating. EDX method and SEM image also showed the alignment as well as the distribution of particles on the coating surface. Catalytic ability of Ni–CeO2 coating and abrasive properties of Ni–CBN coating were tested by special methods, proving composite plating method useful as catalyst sand grinding metal surface.

Three-dimensional nickel nanodomes: Efficient electrocatalysts for water splitting

Highly efficient and stable three-dimensional (3D) Ni nanodome (Ni-NDs) arrays were fabricated as candidate cathode materials for alkaline water splitting. The NDs were prepared by a combined methods of soft lithography-nanosphere lithography, physical vapor deposition (PVD) and electrochemical deposition using polydimethylsiloxane (PDMS) as template. The water splitting activity of the 3D nanostructures were examined in 6 M KOH solution using polarization and electrochemical impedance spectroscopy techniques. The data obtained showed that well-structured and uniformly distributed Ni-NDs could be fabricated using this combined method. The ND arrays perform excellent hydrogen evolution activity with respect to Ni plate as a reference point since their nano-sized roughness results in larger real surface area. By comparing with Ni plate, lower hydrogen onset potential (85 mV) and charge transfer resistance (90.1%) as well as higher current density (90.4%) corresponding to the amount of evolved hydrogen were observed at the NDs. The Ni-NDs have high time-stability in the electrolysis conditions. It is believed that the Ni-ND arrays contribute to the design of novel electrocatalytic electrodes as candidate supporting materials.

Ni-Al phase transformation of dual layer coating prepared by pack cementation and electrodeposition

In this work, Fe-Cr alloys were coated via Aluminum (Al) pack cementation, followed by Nickel (Ni) electrodeposition. The process of pack cementation was done with mixing powders of Al, Al203 and NH4Cl with weight percentage of 15%, 85%, and 5% respectively. To control successful Al diffusion to the substrate, pack cementation was conducted for 7 hours with two holding temperatures treatment at 400 °C for 4 hours, and 800 ° C hours for 2 hours. Subsequently, the electrodeposition of Ni was applied with the solution consisting of NiSO4, H3BO3, and NiCl2. The samples were placed in the cathode, and then dipped in the solutions, while Ni plate used as anode. Successfully the samples were coated by dual Al-Ni layers, the samples were slowly heat treated at 900 °C for 10 hours. The inter-diffusion of Al and Ni were characterized with SEM/EDX to investigate the distribution of the elements. Mechanical properties of the coated substrates were analyzed with Hardness Vickers (HV). It was found the hardness of the substrate increased significantly, from originally 255 HV to the 1177 HV after pack cementation. The hardness of the substrates has decreased to 641 HV after Ni plating, but subsequent heat treatment has been able to increase the hardness to 842 HV. This phenomenon can be correlated to the inward Al diffusion, and outward Fe, Cr diffusion. The formation of intermetallic compounds due to Al inward and Fe, Cr outward diffusion were discussed in details.

Facile morphology-controlled synthesis of nickel-coated graphite core–shell particles for excellent conducting performance of polymer-matrix composites and enhanced catalytic reduction of 4-nitrophenol

We have developed a novel seed-mediated growth method to fabricate nickel-coated graphite composite particles (GP@Ni-CPs) with controllable shell morphology by simply adjusting the concentration of sodium hydroxide ([NaOH]). The fabrication of two kinds of typical GP@Ni-CPs includes adsorption of Ni2+ via electrostatic attraction, sufficient heterogeneous nucleation of Ni atoms by an in situ reduction, and shell-controlled growth by regulating the kinetics of electroless Ni plating in turn. High [NaOH] results in fast kinetics of electroless plating, which causes heterogeneous nuclei to grow isotropically. After fast and uniform growth of Ni nuclei, GP@Ni-CPs with dense shells can be achieved. The first typical GP@Ni-CPs exhibit denser shells, smaller diameters and higher conductivities than the available commercial ones, indicating their important applications in the conducting of polymer-matrix composites. On the other hand, low [NaOH] favors slow kinetics. Thus, the reduction rate of Ni2+ slows down to a relatively low level so that electroless plating is dominated thermodynamically instead of kinetically, leading to an anisotropic crystalline growth of nuclei and finally to the formation of GP@Ni-CPs with nanoneedle-like shells. The second typical samples can effectively catalyze the reduction of p-nitrophenol into p-aminophenol with NaBH4 in comparison with commercial GP@Ni-CPs and RANEY® Ni, owing to the strong charge accumulation effect of needle-like Ni shells. This work proposes a model system for fundamental investigations and has important applications in the fields of electronic interconnection and catalysis.

Highly flexible and ultra-thin Ni-plated carbon-fabric/polycarbonate film for enhanced electromagnetic interference shielding

We report in this work a highly flexible, mechanically robust, and ultra-thin Ni-plated nonwoven carbon fabric/polycarbonate (CF/PC/Ni) film that exhibits outstanding electromagnetic interface (EMI) shielding performance. This composite film is fabricated through a four-step process — fabrication of nonwoven carbon fiber/polypropylene/polyethylene (CEF-NF) fabric, catalytic seeding and sensitization, electroless Ni plating, and lamination with polycarbonate. The as-fabricated ultra-thin (0.31 mm) CF/PC/Ni film exhibits superior EMI shielding effectiveness (EMI-SE) of 72.7 dB, which is close to 3× that of an identical film with no Ni plating (25 dB)—demonstrating Ni plating can substantially improve the EMI shielding performance. Compared with similar lightweight EMI-shielding materials, this CF/PC/Ni film shows a superior EMI-SE at lower density and smaller thickness (1376.1 dB cm2 g−1). 40 min of Ni plating (yielding a Ni thickness of 1.075 μm), followed by 2 MPa of laminating pressure at 190 °C of laminating temperature were found to provide optimal EMI shielding performance. Based on reliability study, the CF/PC/Ni film retains 96.36% of its EMI-SE after 5000 cycles of mechanical bending and 50 h of heating. Therefore, the CF/PC/Ni film exhibits outstanding flexibility, good mechanical strength, and remarkable electrical properties, making it an excellent EMI shielding material.

New industrial application of forward osmosis (FO): Precious metal recovery from printed circuit board (PCB) plant wastewater

As a promising industrial application of forward osmosis (FO), an FO-based concentration system for precious metal recovery from printed circuit board (PCB) wastewater has been newly suggested. This novel FO concentration process utilizes a dilution-needed waste solution possessing high conductivity as a draw solution, and thus an external supply of draw solution as well as a re-concentration process for the diluted draw solution are not required. An electroless (E’less) nickel (Ni) plating solution was evaluated as dilution-needed waste stream-based draw solution, and the test results confirmed that the selected Ni solution could produce an acceptable FO performance, i.e., water flux of 39.4 LMH (active layer facing draw solution (AL-DS) mode with deionized feed solution). From a series of FO experiments conducted with a palladium (Pd) catalyst as a concentration-needed feed solution, the Pd solution was effectively concentrated under an active layer facing feed solution (AL-FS) mode with a slight impact from Pd scaling. The modeling prediction based on our experimental results showed that theoretically Pd can be concentrated 17.2-times-high. The overall performance of our Pd concentration tests indicated that the FO process is promising for concentrating Pd, thereby improving the efficiency of its recycling. The newly proposed system, a recovery-free FO driven by a waste stream, offers attractive economic advantages including (1) zero cost for the supply and re-concentration of the draw solution and (2) enhanced energy efficiency in the precious metal recycling process.

Effect of ultrasonic vibration on activation-electroless nickel plating on Nylon 12 powders

In this work, the electroless nickel plating on Nylon 12 (PA12) powders was developed. The effect of ultrasonic vibration on activation-electroless plating on PA12 powders were investigated systematically using scanning electron microscopy and X-ray diffraction. Results showed amine groups attached on the surface of KH550-modified PA12 powders. The surface structure of modified powders could adsorb the tin and palladium ions, which used as catalyst for the Ni plating. Ultrasonic vibration-assisted activating would facilitate the adsorption of Pd atoms on the surface of PA12 powders, however, hinder nickel atoms plated on the PA12 surface. When the PA12 powders were plated with and without ultrasonic vibration, the palladium content of activated powders were 0.15 and 0.04%, the nickel content of plated powders were 4 and 10%, amorphous shells and nickel particles plated on the surface of PA12 powders, respectively.

Improvement in surface conditions of electroplated Fe-Pt thick-film magnets

Fe-Pt thick-films were electroplated on Ta, Ti, Co, Ni, and Cu plates (substrates) using a direct current, and the surface morphology, the magnetic properties, and the crystal structure of the films were evaluated. The films plated on the Co, Ni, and Cu substrates showed much smooth surface compared with those for the Ta and Ti ones, and we confirmed that the Cu plate was the most attractive substrate due to very small cracks after an annealing for L10 ordering. High coercivity (>800 kA/m) for the Cu substrate is almost the same as that for our previous study in which we employed the Ta substrate, and we found that the Cu plate is a hopeful substrate to improve the surface conditions of electroplated Fe-Pt thick-film magnets.

極細線固定砥粒ダイヤモンドワイヤによる単結晶SiCの精密切断

Single-crystal SiC is an important material for high-power semiconductors, optoelectronic applications because of its good material properties. Compared with silicon, SiC is harder and more difficult to slice, although high precision slicing process is required for a thinner slicing width. A SiC ingot is conventionally sliced using a fixed-abrasive diamond wire, where the core wire diameter is wide approximately 160 μm and diamond grain size is 20 μm. In this study, precision slicing tests were performed for single-crystal SiC by using an extremely fine diamond wire which was a half width of the conventional one. The used diamond wire had two types of core wire diameter, 60 μm and 80 μm, and the grain size was 5-10 μm and 6-12 μm, respectively. The diamond wire was driven in a single direction at a high speed of 1750 m/min. The slicing width, chipping width, workpiece surface roughness, slicing force and diamond protrusion after slicing were investigated experimentally, and a diamond blade which was usually used for slicing SiC was adopted for comparison. During slicing, the Ni plating that covered the diamond grains on the wire was partially removed which maintained the sharp protrusion of the diamond grain. The results showed that by using the proposed extremely fine diamond wire, the chipping width was significantly lowered and the normal slicing force was stable and low. Furthermore, the present study provides high-precision continuous slicing without interval dressing of the diamond wire.

Combinatorial Methods for Improving Lithium Metal Cycling Efficiency

An efficient combinatorial approach for the design and evaluation of surface coatings to improve lithium metal cycling efficiency is demonstrated. The reliability of a 64 electrode combinatorial cell was verified through lithium metal cycling in a range of electrolytes on unmodified Ni and Cu electrode plates with parallel verification using conventional Cu|| Li coin cells. A 1M LiPF6 FEC:TFEC fluorinated electrolyte demonstrated the best performance with coulombic efficiencies of 98.3% and 97.6% in the combinatorial cell (cyclic voltammetry) and coin cell (galvanostatic cycling) respectively, compared to only 91.0% (CV) and 90.3% (galvanostatic) for a 1M LiPF6 EC:DEC control electrolyte. High throughput sputtering was used to deposit different thin film coatings of varying thickness on the 64-channel cell plates to probe the lithium cycling performance as a function of electrolyte and surface coating. Zn surface coatings with thickness between 400–900 nm proved most beneficial; significantly reducing the lithium nucleation potential and leading to more stable cycling at high coulombic efficiency (99.0% in the combinatorial cell with FEC:TFEC electrolyte). These findings not only highlight some useful strategies for improving lithium metal cycling efficiency, but also show the potential for more advanced combinatorial analysis to design superior anodes for lithium metal cells.

Materials Merging Mechanism of Microfluidic Electroless Interconnection Process

A low-temperature, pressureless bonding process, referred to as the microfluidic electroless interconnection process, has been developed for chip-stacking applications, in which electroless Ni plating is employed to bond copper pillars in an attempt to reduce the risk of thermo-mechanical damage during the assembly process. Copper pillar joints with a low standoff height were used to assess the bonding performance of the microfluidic electroless interconnection process on a smaller scale. The results showed that a striking lamellar structure formed in the deposits when electroless Ni solution was fed into a microfluidic platform intermittently, and through this visible structure, the bonding mechanism of the process can be characterized fully. Preliminary results showed that a high level of plating uniformity across the die could be obtained using the microfluidic interconnection process, and that the copper pillars were joined completely by electroless Ni plating without voids or seams. Further, it was found that the process is able to compensate not only for non-uniform copper surfaces, but also for the misalignment of copper pillars, which provides a competitive edge over other bonding methods. In addition, the direct shear test showed that the bond strength of the electroless Ni bonds was quite strong.

Interfacial reaction and failure mechanism of Cu/Ni/SnAg1.8/Cu flip chip Cu pillar bump under thermoelectric stresses

Micro-interconnection copper pillar bumps are being widely used in the packaging areas of memory chip and high performance computer due to their high density, good conductivity and low noise. Studying the interfacial behavior of copper pillar bump is of great significance for understanding its failure mechanism and microstructure evolution in order to improve the reliability of flip chip package. The thermoelectric stress test, in-situ monitor, infrared thermography test, and microstructure analysis method are employed to study the interfacial reaction, life distribution, failure mechanism and their effect factors of Cu/Ni/SnAg1.8/Cu flip chip copper pillar interconnects under 9 groups of thermoelectric stresses including 2104-3104 A/cm2 and 100-150℃. Under thermoelectric stresses, the interfacial reaction of Cu pillar can be divided into three stages:Cu6Sn5 growth and Sn solder exhaustion; the Cu6Sn5 phase transformation, exhaustion and the Cu3Sn phase growth; voids formation and crack propagation. The rate of Cu6Sn5 phase transforming into Cu3Sn phase is positively correlated with the current density. There are four kinds of failure modes including Cu pad consumption, solder complete consumption and transformation into Cu3Sn, Ni plating layer erosion and strip voids. An obvious polar effect is observed during the dissolution of Cu pads on the substrate side and the Ni layer on the Cu pillar side. When Cu pad is located at the cathode, the direction of electron flow is the same as that of the heat flow, and it can accelerate the consumption of Cu pad and the growth of Cu3Sn. When Ni layer serves as the cathode, the electron flow can enhance the consumption of Ni layer. Under 150℃ and 2.5104 A/cm2, the local Ni barrier layer is eroded after 2.5 h, which results in the transformation of Cu pillar on the Ni side into (Cux, Niy)6Sn5 and Cu3Sn alloy. The life of Cu pillar interconnection complies well to the 2-parameter Weibull distribution with a shape parameter of 7.78, which is a typical characteristic of cumulative wear-out failure. The results show that the intermitallic growth behavior and failure mechanism at Cu pillar interconnects are significantly accelerated and changed under thermoelectric stresses compared with the scenario under the single high temperature stress.

Laser Direct Writing and Selective Metallization of Metallic Circuits for Integrated Wireless Devices.

Portable and wearable devices have attracted wide research attention due to their intimate relations with human daily life. As basic structures in the devices, the preparation of high-conductive metallic circuits or micro-circuits on flexible substrates should be facile, cost-effective, and easily integrated with other electronic units. In this work, high-conductive carbon/Ni composite structures were prepared by using a facile laser direct writing method, followed by an electroless Ni plating process, which exhibit a 3-order lower sheet resistance of less than 0.1 ohm/sq compared to original structures before plating, showing the potential for practical use. The carbon/Ni composite structures exhibited a certain flexibility and excellent anti-scratch property due to the tight deposition of Ni layers on carbon surfaces. On the basis of this approach, a wireless charging and storage device on a polyimide film was demonstrated by integrating an outer rectangle carbon/Ni composite coil for harvesting electromagnetic waves and an inner carbon micro-supercapacitor for energy storage, which can be fast charged wirelessly by a commercial wireless charger. Furthermore, a near-field communication (NFC) tag was prepared by combining a carbon/Ni composite coil for harvesting signals and a commercial IC chip for data storage, which can be used as an NFC tag for practical application.

Effect of the Addition of Molybdenum on the Structure and Corrosion Resistance of Zinc–Iron Plating

Zn–Ni plating is indispensable in various industries because of its high corrosion resistance. However, Ni has been reported to trigger allergies; thus, an alternative Ni-free plating is desired. Zn–Fe plating is considered to be a promising candidate, albeit its corrosion resistance still needs to be improved. The corrosion resistance of Zn–Fe plating is expected to increase by the addition of Mo as the third alloying element as it is more noble than Zn and Fe. In this study, Zn–Fe–Mo plating with a corrosion resistance nearly equivalent to that of the Zn–Ni plating was fabricated. Zn–Fe–Mo plating was electrically deposited from continuously-agitated plating baths prepared by mixing ZnSO4, FeSO4, Na2MoO4, Na3C6H5O7, and Na2SO4 using Fe or Ni plates as the substrate. The surface morphology, composition, crystal phase, and electronic state of Mo of the platings were investigated by scanning electron microscopy equipped with energy-dispersive spectroscopy (SEM-EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The anti-corrosion performance was evaluated by Tafel extrapolation method. Formation of plating comprising a Mo containing alloy phase was found to be crucial for improving corrosion resistance. The Zn–Fe–Mo plating demonstrates promise for replacing anti-corrosion Zn–Ni platings.

Improving the electrocatalytic activity for hydrogen evolution reaction by lowering the electrochemical impedance of RuO2/Ni-P

In this paper Ni-P, RuO2 and RuO2/Ni-P composites were deposited on Ni plates through pulsed electrodeposition method, and their activities for HER in alkaline solution were studied comparatively. Scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) analysis confirmed the formation of every composite. The electrochemical impedance spectroscopy (EIS) showed that Ni-P/Ni had lower charge transfer resistance at high overpotential and higher charge transfer resistance at low overpotential than RuO2/Ni. While Ni-P/Ni exhibited lower catalytic activity for HER at low overpotential and higher catalytic activity at high overpotential than RuO2/Ni. Meanwhile, RuO2/Ni-P/Ni had the lowest charge transfer resistance and highest catalytic activity among the three electrodes at both low and high overpotentials. It indicated that RuO2/Ni-P/Ni with less Ni-P and RuO2 exhibited enhanced catalytic activity for HER than both RuO2/Ni and Ni-P/Ni, due to an electron charge transfer synergistic effect of RuO2 and Ni-P.