Ni Plating Process Research Articles

Novel in-situ electroflotation driven by hydrogen evolution reaction (HER) with polypyrrole (PPy)-Ni-modified fabric membrane for efficient oil/water separation

Efficient separation of oil/water emulsion is still a worldwide challenge. Herein, a new conception/strategy of in-situ electroflotation driven by hydrogen evolution reaction (HER) combining with a polypyrrole (PPy)-Ni-modified fabric membrane was proposed for efficient oil/water separation. To realize this new conception, nickel-decorated polyester fabric membrane was successfully fabricated via facile electroless Ni plating process on the polypyrrole (PPy)-modified surface. The Ni-decorated fabric membrane processed superhydrophilicity, underwater superoleophobicity and excellent electrical conductivity (electrical resistance of ~14.1 Ω), which could serve as cathode for HER. The fabric membrane itself couldn't separate oil/water emulsion, but achieved extremely high permeation (above 12526.5 L m−2 h−1) and oil rejection (above 98.6%) for separating stratified oil/water mixtures under gravity force. By applying an extra electric field on the conductive fabric membrane, an in-situ electroflotation process driven by HER can be produced. Under the optimized electroflotation conditions (20.0 V cm−1 electric field intensity, 20 g L−1 electrolyte concentration and 30 min electroflotation time) in this study, this new process could efficiently separate oil/water emulsion with high permeation flux (840.6 L m−2 h−1) and oil rejection (98.5%). The present work provided a new conception of in-situ electroflotation-membrane separation process for treatment of oily wastewater, showing strong application significance.

Enhancement of fiber–matrix adhesion in carbon fiber reinforced Al-matrix composites with an optimized electroless plating process

Coating is the most common method to offer better wettability between carbon fibers (CFs) and metal matrix of the composites. An optimal electroless Ni plating process was studied in this paper to improve the interfacial adhesion of CF reinforced Al-matrix composites. By using Pd-colloid activation, the typical island-like agglomeration on the coating surface was significantly eliminated, providing a Rq reduction of 56.5%. Applying strong-oxidizing mixed acid (SMA) etching provided larger adhesion force (140.53 nN) and interfacial shear strength (IFSS) (35.1 MPa) than that of the original process (53.72 nN and 31.1 MPa), which can be attributed to rougher surface and larger numbers of carboxyl functional groups on CF surface. By combining these processes, the adhesion force further increased to 207.99 nN with improved IFSS to 40.9 MPa, and Rq was reduced by 72.1%. The ultimate tensile strength (UTS) of the composites increased to 140 MPa, which is 35.9% higher than that with CFs by original method.

Ni-coated graphene nanoplatelets and their application as reinforcements for WC-Co cemented carbides

In the current research, Ni-coated graphene nanoplatelets (Ni-GNPs) were fabricated by electroless Ni plating process. The Co-cemented tungsten carbides (WC-Co) samples doped with Ni-GNPs were obtained by vacuum hot pressing sintering. The effect of various content of Ni-GNPs on the mechanical and frictional properties of as-sintered WC-Co samples was investigated. Vickers hardness of WC-Co samples decreased from 1896 MPa to 1743 MPa with the content of Ni-GNPs varied from 0.0 wt% to 0.4 wt%. The fracture toughness reached to the highest value of 10.85 MPa · m1/2 with 0.05 wt% Ni-GNPs. The friction coefficient dropped from 0.43 of the sample with 0.0 wt% Ni-GNPs to 0.21 of the sample with 0.4 wt% Ni-GNPs. The results revealed that the Ni-GNPs have considerable effect on improving the combination properties of WC-Co cemented carbides. Within the mentioned content range, the optimal content of the Ni-GNPs in WC-Co sample was 0.05 wt%.

The effect of pH on synthesizing Ni-decorated MWCNTs and its application for Sn-58Bi solder

Nickel-decorated multi-walled carbon nanotubes (Ni-MWCNTs) were synthesized using a colloidal method and an electroless plating method to form Ni nanoparticles on the surface of MWCNTs. The Ni electroless plating process was optimized with solutions at various pH (5, 6, 7, and 8) levels. The Ni-MWCNTs fabricated at pH 7 show the most stable Ni nanoparticles on the surface of the MWNCTs. After optimization of the Ni plating process, the Ni-MWCNTs/Sn-58Bi composite solder were fabricated with varying contents of (0, 0.05, 0.1 and 0.2 wt%) Ni-MWCNTs. The experimental results show that Ni-MWCNTs enhance the mechanical properties of Sn-58Bi solder. The shear strength of Sn-58Bi solder improves by about 14% with 0.1 wt% Ni-MWCNTs. Furthermore, the microstructure evolution after a high temperature storage test shows that Ni-MWCNTs have an effect on grain refining and interrupt growth of the Intermetallic compound layer. The distribution of Ni-MWCNTs could be recognized with the results of EPMA.

Wetting of molten Sn-3.5Ag-0.5Cu on Ni-P(-SiC) coatings deposited on high volume faction SiC/Al composite

Abstract The wetting of molten Sn-3.5Ag-0.5Cu alloy on the Ni-P(-SiC) coated SiCp/Al substrates was investigated by electroless Ni plating process, and the microstructures of the coating and the interfacial behavior of wetting systems were analyzed. The SiC particles are evenly distributed in the coating and enveloped with Ni. No reaction layer is observed at the coating/SiCp/Al composite interfaces. The contact angle increases from ∼19° with the Ni-P coating to 29°, 43° and 113° with the corresponding Ni-P-3SiC, Ni-P-6SiC and Ni-P-9SiC coatings, respectively. An interaction layer containing Cu, Ni, Sn and P forms at the Sn-Ag-Cu/Ni-P-(0,3,6)SiC coated SiCp/Al interfaces, and the Cu-Ni-Sn and Ni-Sn-P phases are detected in the interaction layer. Moreover, the molten Sn-Ag-Cu can penetrate into the Ni-P(-SiC) coatings through the Ni-P/SiC interface and dissolve them to contact the SiCp/Al substrate.

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.

Origin of corrosion effects in solar cell contacts during electrochemical nickel deposition

In the present study, the chemical interaction between screen-printed solar cell front-side contacts and electrolyte solutions is investigated in detail. Especially the Ni-plating process is known to lower the mechanical adhesion of solar cell contacts significantly. The mechanisms behind this adhesion loss were analyzed by performing contact exposure experiments with and without applied voltage in electrolyte solutions with subsequent characterization of the contact peel-force, complemented with X-ray-diffraction investigations of the material changes in the solid contact compounds. Reaction paths, behind the contact corrosion, as observed in SEM images, were identified: PbO and Ag2O out of the contact react with sulphates and chlorides in the electrolyte, forming lead sulphate and silver chloride. If a voltage is applied to the contacts an alternative more effective reaction path were identified. The voltage offers the possibility to reduce the dissolved lead and silver, and this shifts the equilibrium reactions strongly towards further dissolution. The activity of the reduction was found to depend on the reduction potential of the cations in the used electrolyte solution. The less noble the metal to be deposited on the solar cell contacts, the more difficult it is to achieve the deposition without adhesion loss of the screen-printed solar cell contact.

Moisture and Hydrogen Release in Optoelectronic Hermetic Packages

In this work the effect of nickel (Ni) plating process on the hydrogen (H) and moisture content of hermetic packages such as those used in optoelectronics was investigated. The work offers an explanation of moisture formation inside hermetic packages by showing that the problem arises from the electroless plating of Ni, which is found to be inherently rich in H. The effects of the Ni plating process, baking, and Au thickness on the moisture and hydrogen content of hermetic packages were thoroughly explored. It was observed that baking the package components before sealing alleviates the problem of moisture formation inside the package but does not fully eliminate it. It was only after changing the Ni plating process from electroless to electrolytic that the moisture problem actually disappeared. This investigation showed that moisture formation inside hermetic packages is due to H evolution from the electroless Ni which eventually reacts with surface oxides to form H2O. SIMS analysis of electroless and electrolytic Ni showed that electroless Ni is around 10-fold richer in H compared with its electrolytic counterpart. SIMS analysis also showed that H content in electroless Ni can be significantly reduced with heat treatment.

Moisture and Hydrogen Release in Optoelectronic Hermetic Packages

In this work we investigated the effect of Nickel (Ni) plating process on the Hydrogen (H) and moisture content of hermetic packages such as those used in optoelectronics. The work offers an explanation of moisture formation inside hermetic packages by showing that the problem arises from the electroless plating of Ni which is found to be inherently rich in H. The effects of the Ni plating process, baking, and Au thickness on the moisture and hydrogen content of hermetic packages were thoroughly explored. It was observed that baking the package components before sealing alleviates the problem of moisture formation inside the package but it doesn't fully eliminate it. It was only after changing the Ni plating process from electroless to electrolytic that the moisture problem actually disappeared. Our investigation showed that moisture formation inside hermetic packages is due to H evolution from the electroless Ni which eventually reacts with surface oxides to form H2O. SIMS analysis of electroless and electrolytic Ni showed that electroless Ni is around ten folds richer in H compared to its electrolytic counterpart. SIMS analysis also showed that H content in electroless Ni can be significantly reduced with heat treatment.

Properties of magnetic nickel/porous-silicon composite powders

The magnetic and photoluminescence (PL) properties of nickel/porous-silicon (Ni/PSi) composite powders are investigated. Ni/PSi composite powders are prepared by stain etching of Si powder in a HF/HNO3 solution followed by electroless plating of Ni nanoparticles on the stain-etched PSi powder in a NiCl2 solution. The Ni/PSi powders exhibit hydrophillicity, superparamagnetism caused by the deposited Ni nanoparticles, and orange-red PL owing to the nanostructured PSi surface. The degree of magnetization decreases with increasing Ni plating time, indicating its dependence on the size of the Ni nanoparticles. The Ni/PSi composite powders also show a stronger magnetization as compared to that of the Ni-particle-plated Si powder. The stronger magnetization results from the larger surface area of PSi. The PL intensity, peak wavelength, and lifetime of Ni/PSi are strongly dependent on the NiCl2 concentration. This dependence is due to the different thickness of the oxide overlayer on the PSi surface formed during the Ni plating process. The existence of the oxide overlayer also results in a small change in the PL intensity against excitation time.

Restoration Technology of 30CrMnSiA Steel Parts on Airplane by Electroless Ni-Plating

The feasibility of electroless Ni-plating was explored in order to solve the problem of the restoration of the parts of aircraft made of high strenth steel. The flow and criterion of the restoration technology were were preliminarily investigated. We have measured the hardness, adhesion strength and antiwear performance of the coating. The results show that the electroless Ni-plating process for restoring the scuffed surface of aircraft parts made of high strenth steel has the advantages of simple procedure, easy operationg, and low cost. The coating is well adhered to the substrate and meets with the requirement for performance. In one word, the restoration technology of aircraft parts made of high strenth steel is good for extending.

The effect on the microstructures of electroless nickel coatings initiated by pulsating electric current

In this study, pulsating electric current was applied during the electroless Ni plating process. The applied current is controlled to avoid the formation of an immersion (displacement) deposit. The effects of the current density (0.5 and 1.0 A/dm 2), duty cycle (0 to 100%, in a step of 10%), and bath pH value (4.4 and 4.8) were investigated systematically. The as-plated coatings were examined by atomic force microscopy, transmission electron microscopy, X-ray diffraction, synchrotron X-ray absorption spectroscopy, etc. Amorphous or amorphous-like microstructure was obtained for all as-plated coatings and the phosphorus content was higher than 8.9 wt.%. Experimental results showed that pulsating electric current can initiate Ni nanocrystallization (∼ 5 nm), improve crystal growth, and accelerate electroless Ni deposition. An obvious increase in deposition rate was also observed with pulsating electric current.

メッキ廃液からの有価金属の回収に関する研究 Ｉ 化合物沈澱法によるＮｉの回収

Since Ni is a valuable resources and its plating solution is costly, improvements in recycling technique from waste solution and slurry in the Ni plating process have been an necessity. In this paper, the retrieval of Ni from the electroless plating waste waters, especially worn-out ones with high concentration of Ni is considered. The compound precipitation method which retrieves Ni from waste waters as carbonate form or oxalate form is examined.The results show that higher solution temperature is preferable, and that Fe can be removed by neutralization precipitation. Among carbonate, Na2CO3 turns out to be the more effective precipitator than NaHCO3. When the double dose or more of the theoretical equivalent of Na2CO3 were added, and the initial pH was larger than 2, precipitation took the form of weak crystalline whose composition was Ni(CO)3(OH)4 · 4H2O. When NaHCO3 was used as precipitator, together with CO2 bubbling, globular particles precipitated.For oxalate, crystalline particles of NiC2O4 · 2H2O precipitated. The method was tested for waste water from an actual plant and followings were suggested: Ni-B solution should be precipitated with carbonate, while Ni-P solution with oxalates.

Methodology for studying the impact of intrinsic stress on the reliability of the electroless Ni UBM structure

A methodology for evaluating the reliability and the impact of intrinsic stresses on the electroless Ni under bump metallurgy (UBM) structure is presented. The first part of this work will address the testing methodology, which uses a pressure sensing device to determine the intrinsic stress in Ni due to the plating process. An optical method is used to capture deformation in the sensing device due to the Ni plating process. A finite element model is then used to calculate the intrinsic stress in the Ni film using the deformation output from the optical measurements. The second part of this work will address a predictive model used to determine the reliability of applying intrinsic stress values to a low cost electroless Ni UBM structure during the bump formation and solder reflow process. The combined work of the testing and predictive methodology provides a more effective and accurate method of predicting the Ni UBM reliability.

High rate magnetron RIE of thick polyimide films for advanced computer packaging applications

High performance (high speed and high wiring density) computer packaging can be obtained by applying thin film technology to the multichip interconnection structure. The thickness of the layers, as determined by the electrical requirements, necessitates the use of a via-fill process in conjunction with straight-wall openings in the dielectric layers. The packaging performance and wiring density is improved through reduced via areal dimensions (increased number of lines per layer), through elimination of stepcoverage limitations, and through better planarity thus increasing the number of signal and power layers. The MCNC split cathode magnetron was found to be the best RIE system for obtaining high rate low pressure oxygen RIE of polyimide films. The polyimide etch process was studied, characterized and optimized for the anisotropic residue free etch of 4 µm to 12 µm thick polyimide films. The etched wafers were then processed through the subsequent via filling step and reproducible planar via-filling was achieved with an electroless Ni plating process.