Electroless Copper Plating Method Research Articles

Thermal-Conductivity-Enhancing Copper-Plated Expanded Graphite/Paraffin Composite for Highly Stable Phase-Change Materials.

Paraffin (PA)/expanded graphite (EG) is an important composite phase change material with low cost, high heat storage, good thermal conductivity and cycling stability. Its thermal conductivity needs to be further improved for application in the thermal management system of power lithium-ion batteries. In this paper, copper plated expanded graphite (CPEG) with 3D porous structure was prepared by electroless copper plating method, which was used as thermal conductivity enhancing material to replace part of EG in PA/EG composite materials. For the optimized phase change material composed of 80%PA-14%EG-6%CPEG, the copper content is very low (0.768 wt%), but its thermal conductivity can be significantly improved without loss of latent heat and thermal cycling stability. Its thermal conductivity is increased from 11 times to 16.5 times that of paraffin while compared with the copper-free composite material (80%PA-20%EG). The PA/EG/CPEG composite material exhibits good temperature control effect on power lithium-ion batteries.

Development and characterization of conductive textile (polyester fabric) for wearable electronics by using electroless metallization

This paper investigated the development and characterization of conductive textured and non-textured polyester fabrics with various cross-sections. To impart conductivity on fabric structures, the electroless copper plating method was chosen. Electrical conductivity, thickness, electron scanning microscopy (SEM), microscopic morphology, and energy dispersive X-ray spectroscopy were used to characterize the deposition of copper nanoparticles on textured and non-textured polyester fabrics (EDX). SEM images revealed a thin film of uniform copper nanoparticle coating on textured and non-textured polyester fabrics. Electrical conductivity, wear resistance, thickness, and durability of conductive textured polyester fabrics were compared to non-textured conductive polyester fabrics. Electrical conductivity measurements show that both textured and non-textured polyester fabrics have good electrical conductivity values of 27Ω/cm, 85Ω/cm, 52Ω/cm, 9Ω/cm, 98Ω/cm, 133Ω/cm. When conductive polyester fabrics were tested for durability against washing and rubbing fastness, the textured polyester fabrics retained copper nanoparticles well by maintaining their electrical conductivity level after 250 abrasion and washing cycles, with best electrical conductivity values of 177Ω/cm and 29Ω/cm, respectively.

Microstructure evolution and mechanical properties of copper coated graphene nanoflakes/pure titanium matrix composites

In this paper, a new electroless plating method to prepare copper @ graphene nanoflakes ([email protected]) powders with different content of GNFs was developed. Then, the short-term ball milling and spark plasma sintering (SPS) were used to fabricate [email protected]/Ti composites. The electroless copper plating method effectively improves the dispersion of GNFs and relieve the severe interfacial reaction between GNFs and Ti. Microstructures and the morphology of the mixed powders and the composites were characterized by the scanning electron microscopy (SEM), Raman spectroscopy, X-Ray diffraction (XRD), and transmission electron microscopy (TEM). The micro-hardness and compressive properties were measured for evaluating [email protected]/Ti composites. Results showed that the yield strength and microhardness of the composites enhanced gradually with the increase of the GNFs content. The compressive yield strength of the 0.5 wt% [email protected]/Ti composite reaches 693 MPa, which is increased by 179% compared with that of pure Ti (248 MPa). The high ductility of 50% was maintained. At the same time, the 0.5 wt% [email protected]/Ti composite has a microhardness value of 281 HV, 97% higher than that of pure Ti (142 HV). Furthermore, the strengthening mechanism of mechanical properties of composites was discussed.

Electroless plating of a 5G copper antenna on polyimide patterned with laser-induced selective activation and curing of metal–organic catalyst

An improved electroless copper plating method for fabricating 5G/Sub-6 GHz antennas is reported. A catalyst, palladium ion/4-vinylpyridine (Pd2+/4VP) complex, which not only initiated electroless copper plating but also promoted the adhesion of the copper layer, was dip-coated onto a polyimide (PI) substrate. Selective curing and activation of the Pd2+/4VP complex catalyst were induced by a pulsed UV laser. Wherever the laser scanned on the PI substrate, the palladium ions were reduced to palladium atoms, and the free radicals created from the decomposition of tert-butyl peroxybenzoate (TBPB) initiated the copolymerization of 4VP and PI, which enhanced the adhesion of the catalyst on the substrate. The unreacted Pd2+/4VP was removed by ethanol and collected for reuse, hence a much-reduced material cost. By adjusting the laser power, scanning speed, defocusing distance, and electroless plating time, the optimized process condition for Cu circuit fabrication without damaging the PI substrate was found. A high-quality copper circuit pattern was achieved with a laser power of 100 mW, a scanning speed of 330 mm/s, a defocusing distance of 2.0 mm, and an electroless plating time of 40 min. The copper patterns exhibited excellent adhesion and maintained good conductance after the bending fatigue tests. This laser treatment approach is simple, cost-effective, and applicable to non-planar 3D substrates, and the usefulness of this method was demonstrated by fabricating a 5G/Sub-6 GHz antenna with good device performances.

Fabrication of conductive soybean protein fiber for electromagnetic interference shielding through electroless copper plating

We report on a simple but efficient strategy for the preparation of conductive soybean protein fiber (SBPF) by electroless copper plating method. The proposed method mainly composed of three procedures, namely, 3-aminopropyltrimethoxysilane (APTMS) modification, Cu0-seeding and Cu-coating deposition. Specifically, Cu0 activation procedure could be divided into two stages: Cu2+-absorption in cupric citrate solution and the subsequent in situ reduction to Cu0 with sodium borohydride. The elemental analysis of the samples in each step was carried out by using XPS measurement. In addition, the resultant SBPF-based Cu coating was subject to detailed analysis by SEM. It was found that a layer of fine Cu particles evenly distributed on the fiber surface with uniform grains and there were no obvious structural damages after the ultrasonic washing test. In contrast, the Cu coating obtained in absence of APTMS modification suffered a delamination, which confirmed the necessity of chemical modification on SBPF. Moreover, the resultant conductive soybean protein fibers were woven into plain weave in a single cylinder handloom, then corresponding shielding effectiveness values were measured by using a spectrum analyzer at frequency range of 30–1000 MHz.

Electromagnetic shielding effectiveness and serviceability of the multilayer structured cuprammonium fabric/polypyrrole/copper (CF/PPy/Cu) composite

In this paper, we developed a simple and robust synthesis route to fabricate multilayer structured cuprammonium fabric/polypyrrole/copper (CF/PPy/Cu) composite, which could be potentially used as electromagnetic interference (EMI) shield due to its characteristics of both EM wave-absorption and EM wave-reflection. PPy layer was directly deposited onto the bare CF substrate via an in-situ polymerization approach, and the interaction mechanism between PPy and CF substrate was investigated by FT-IR and FT-Raman measurements. The results indicated that the interaction between PPy (NH) and CF (>COH) substrate was by hydrogen bonding. Afterwards, Cu film was constructed on the as-made PPy coated CF (CF/PPy) by an electroless copper plating method. The elemental analysis of the samples in each step was conducted by using XPS measurement. XRD analysis showed that the top Cu film had a characteristic face-centered cubic (FCC) crystalline structure. SEM images illustrated that the thickness of the PPy film was about 1.52μm with 11.4% deviation, which was enough to generate the inter-fiber connection. Moreover, the probable growth mechanism of top-Cu films was proposed according to their surface morphologies. The shielding effectiveness (SE) values of copper plated CF (CF/Cu) and CF/PPy/Cu were recorded and compared by using a Spectrum analyzer (30–1000MHz). The resultant CF/PPy/Cu composite had a higher EMI SE (30.3–50.4dB) with sheet resistance of 85.8mΩ/sq. The results of ultrasonic washing, TGA and tensile measurements revealed that the proposed conductive fabric exhibited an excellent serviceability, which was adequately reliable for practical application.

Preparation and properties of W–Cu–Zn alloy with low W–W contiguity

The W–Cu–Zn alloy with α-brass matrix and low W–W contiguity was prepared by method of electroless copper plating combined with spark plasma sintering (SPS) method. The effects of process and parameters on the microstructure and mechanical properties of the alloy were investigated. The W–Cu–Zn alloy with a relative density of 96 % and a W–W contiguity of about 10 % was prepared by original fine tungsten particles combined with wet mixing method and SPS solid-state sintering method at 800 °C for 10 min. The microstructure analysis shows that Cu–Zn matrix consists of nano-sized α-brass grains, and the main composition is Cu3Zn electride. The nano-sized Cu was coated on the surface of tungsten particles by electroless copper plating method, and the fairly low consolidation temperature and short solid-state sintering time result in the nano-sized matrix phase. The dynamic compressive strength of the W–Cu–Zn alloy achieves to 1000 MPa, but the alloy shows poor ductility due to the formation of the hard and brittle Cu3Zn electrides. The fine-grain strengthening and the solution strengthening of the Cu–Zn matrix phase are responsible for the high Vickers microhardness of about 300 MPa for W–Cu–Zn alloy.

Study on Preparation and Mechanical Properties of W-Cu Alloy with Low W-W Contiguity

Electroless copper plating method combined with spark plasma sintering (SPS) was used to fabricate W-Cu alloy with low W-W contiguity. Results show that W-Cu alloy with low W-W contiguity and high relative density can be obtained by this method. With sintering temperature increased from 860°C to 1060°C, the relative density of W-Cu alloy shows a rapidly increasing tendency, but the W-W contiguity keeps at a low level. Compression testing results show that the ductility of prepared W-Cu alloy is sensitive to strain rate, and the failure strain of the W-Cu alloy shows obviously increasing tendency with the loading strain rate increased from 10-3 to 103.

Surface modifying of SiC particles and performance analysis of SiCp/Cu composites

In this study, the electroless copper plating method was applied to deposit a Cu coating on SiCp in order to improve interface bonding performance. The SiCp surface morphology with uncoated and coated copper was investigated. The SiCp/Cu composite was fabricated by the hot-pressed sintering technology. SiC particles with various contents were used as reinforcement. The results showed that the distribution of reinforced particle with electroless plating copper coating was uniform in the copper matrix. The SiCp content played had an important role on thermal expansion coefficient and wear properties behaviors of the SiCp/Cu composites. The wear resistance capacity and thermal expansion coefficient of the composites decreased with increasing amount of SiC. Compared with the pure Cu matrix, the obtained SiCp/Cu composites had better capacity of the wear resistance. The SiCp/Cu composites increased when compared with the pure Cu material.

Electroless plating route to the synthesis of glass microspheres/copper composites with excellent conductivity

A versatile electroless copper plating method for the fabrication of Cu-coated glass microspheres was successfully developed using hydrazine hydrate as the reducing reagent. To obtain the best morphology and electrical conductivity of Cu-coated glass microspheres, some main synthetic factors including the concentration of copper salt, volume of aqueous ammonia and bath temperature were investigated in detail. The crystal structure and shape of the copper layer were characterised by X-ray diffraction and scanning electron microscope techniques. The result showed that the glass microspheres with a uniform copper coating exhibited a face-centred cubic crystal structure and an excellent volume resistivity (ρν) of 4.28 × 10−4 Ω·cm. This method could also be extended for the fabrication of Ag- and Co-coated glass microspheres with superior conductivity.

Microwave absorption properties of fabric coated absorbing material using modified carbonyl iron power

The modified absorbing agent was prepared by depositing copper particles on carbonyl iron power (CIP) using a ultrasonic electroless copper plating method. Subsequently, a fabric coated absorbing material was fabricated on non-woven fabric coated absorbing dope containing 85 wt% modified CIP. Scanning electron microscope (SEM) and energy dispersion spectrum (EDS) were used to analyze the microstructure and components of modified CIP. Electromagnetic parameters of modified CIP and reflectivity losses of multi-layer fabric coated absorbing material were measured by a 3 cm waveguide system. The results showed that copper particles were successfully deposited on the surface of CIP. Compared with initial CIP, the values of the complex permeability and permittivity of modified CIP increased after CIP was disposed by ultrasonic electroless plating process, which resulted in a minimum reflection loss −8.43 dB with the thickness of about 2 mm in the frequency range of 8–12 GHz. Furthermore, non-woven fabric absorbing material has a reflection loss −26 dB with the matching thickness of 2.08 mm at 9.35 GHz. It was concluded that ultrasonic electroless copper plating process had great effects on increasing microwave absorption properties of CIP. Moreover, structure of non-woven fabric had a contribution to improve absorbing performance. In addition, because fabric used was light enough, monolayer non-woven fabric coated absorbing material (FCAM) had a low planar density about 0.2 kg/m 2.

Electroless Copper Plating on Ti<sub>3</sub>SiC<sub>2</sub> Powder Surface Using Ascorbic Acid as a Reducing Agent

Cu-coated Ti3SiC2 powder was fabricated by electroless copper plating method from CuSO4 using poisonless ascorbic acid (C6H6O4(OH)2) as reducing agent. Sensibilization and activation on Ti3SiC2 powder surface was performed by Sn-Ag catalyst system. Surfactants lauryl sodium sulfate (SDS) and Polysorbate 80 (Tween-80) were used as modifiers to control copper particle sizes and shapes. It is found that good pretreatment and activation can obtain fully-formed copper coating. The optimal copper deposition rate can reach to 2.053 g.dm-2.h-1 at 80°C . The best coating effect can be obtained in the samples modifying with 12g/L SDS+8ml/L Tween-80.

Electroless copper plating bath, electroless copper plating method and electronic part

Electroless copper plating bath, electroless copper plating method and electronic part

An electroless copper plating method for Ti, Zr-based hydrogen storage alloys

An acidic electroless copper plating method using HF has been developed and applied to the hydrogen storage alloy: Zr0.5Ti0.45V0.54Ni0.87Cr0.15Co0.21Mn0.24. It is shown that the copper plating mechanism is an ion-exchange process between alloy elements and copper ions. The resulting copper coating is metallic. The coated copper layer significantly improved activation properties of the alloy electrode for a Ni–MH secondary battery. Anodic polarization curves and SEM micrographs showed that the reason for this improvement is due to the dissolution of a surface oxide film by HF during the copper plating. This coating method was also successfully applied to eight other Zr(Ti) alloy powders with different compositions. It can be concluded that this electroless copper plating method can be widely applied to Ti(Zr)-based hydrogen storage alloys of various compositions which had been regarded to be difficult to coat by conventional electroless copper plating methods.

The optimal condition of acidic electroless copper plating method for Ti, Zr-based hydrogen storage alloys for electrode use

An acidic electroless copper plating using HF for titanium and zirconium-based hydrogen storage alloys shows a significant improvement in activation and discharge capacity of the alloy electrodes even though the plating process is simple. In this paper, the optimal conditions of this acidic electroless copper plating have been investigated for Ti, Zr-based AB2-type alloy powders for a negative electrode of a Ni–MH secondary battery. Zr0.5Ti0.45V0.54Ni0.87Cr0.15Co0.21Mn0.24 alloy powder was coated by copper under various coating conditions (amount of catalytic agent, stirring speed and temperature of coating bath, and amount of coated copper) and the coatings were examined by S.E.M. The electrodes prepared by the copper coated alloy powders were electrochemically tested. Considering the electrode properties and economics, it is suggested that the optimal coating conditions are: 0.2 ml as an amount of agent (HF), 400 rpm as a stirring speed, 25°C as a coating temperature and 2 wt% as an amount of coated copper for 0.3 g of alloy in 50 ml of distilled water.

TPR study of electroless plated copper catalysts

An electroless copper plating method, an impregnation method, and a precipitation method were used to prepare copper/alumina catalysts with different loadings. Temperature-programmed reduction (TPR) was employed to characterize the reducibility of copper catalysts prepared by different methods. The experimental results showed that the copper catalyst prepared by electroless plating method had the lowest reduction temperature, followed by the catalyst prepared by the precipitation method, and the catalyst prepared by the impregnation method had the highest reduction temperature.

Characterization and dehydrogenation activity of [formula omitted] catalysts prepared by electroless plating technique

Seven new alumina supported copper catalysts prepared by the electroless copper plating method and the support itself were investigated to characterize by X-ray diffraction (XRD), scanning electron micrography (SEM) and electron probe microanalysis (EPMA). Dehydrogenations of isopropanol and cyclohexanol were individually conducted to test the activity of these catalysts. The copper surface area was measured by the selective chemisorption of nitrous oxide and the acidity was measured by the chemisorption of ammonia using the volumetric method. Besides the BET surface area, pore size distribution was also measured. The results showed that the BET surface area linearly decreased with the copper loading of the catalyst. Copper formed crystallites at a minimum loading (ca. 7 wt.% Cu) and the crystallite diameter ( d B) was almost independent of loading. The copper surface area increased with copper loading up to ca. 15 wt.% Cu and then decreased with further deposits. The acidity of catalyst also decreased with copper loading up to a certain copper content, further deposition of copper had no significant effect on it. The catalysts prepared by the electroless plating method showed a relatively higher acidity than the catalysts prepared by the precipitation method. It was found that the dehydrogenation activity strongly depended upon the free exposed copper sites available for alcohol adsorption and reaction and the selectivity was a function of acidity of the catalysts as well as the reaction temperature.

Dependence of selectivity on the preparation method of copper/α-alumina catalysts in the dehydrogenation of cyclohexanol

An electroless copper plating method, a precipitation method and an impregnation method were used in the preparation of eleven Cu/α-Al 2O 3 catalysts. The effects of the method of preparation on the dehydrogenation reaction of cyclohexanol were investigated. The results showed that the dehydrogenation activity increased as the copper loading increased up to a certain limit and then declined with further copper loading. The selectivity to cyclohexanone also increased as copper loading increased up to a certain limit, then decreased as copper loading increased for the catalyst prepared by the impregnation method. For the catalysts prepared by the electroless method the selectivity remained aemost the same. For the precipitation method the selectivity was very poor. The activation energy was lowest for ELE-3, intermediate for IMG-2 and highest for PRE-2. According to our findings, the catalysts prepared by the electroless method are better than those prepared by the other two methods, and the catalyst ELE-3 is the best one among the eleven catalysts tested.

無電解銅めっきにおけるフェナントロリン添加剤の作用機構

An electroless copper plating method using EDTA (ethylenediaminetetraacetic acid) as a complexing agent and HCHO as a reducing agent has been studied. Additives used were 2, 9-dimethyl-1, 10-phenanthroline (2, 9-dmph) and 5, 6-dimethyl-1, 10-phenanthroline (5, 6-dmph).The working mechanism of 2, 9-dmph, which had a cuproine functional group, was the reiteration of the following three steps:1. adsorption of 2, 9-dmph on the copper working electrode;2. production of Cu (I) (2, 9-dmph)2 complex on the electrode; and3. transference of the Cu(I)-complex to the plating solution.As a result, 2, 9-dmph prevented the active alcoholate ion from being adsorbed on the working electrode. Since the characteristic wave disappeared, polarization characteristics were explicable by the mixed potential theory, and copper complex ion Cu (II)Y2- was directly reduced to metallic copper. The surface of the deposit was uniform and the grains were linked. The cross section of the deposit was virtually identical to that of metallic copper.In the case of 5, 6-dmph, which had a ferroine functional group, copper complex Cu (I) (5, 6-dmph)2 formed on the electrode failed to transfer to the plating solution, and the mixed potential theory did not hold. The deposit was amorphous. The surface of the deposit was rough and the cross section was spongy.