Electroless copper plating on microcellular polyurethane foam

In order to obtain substrates with good conductive foam for high porosity foam metal materials used in the metal electrodes,the technique of electroless copper plating on the microcellular polyurethane foam with pore size of 0.3 mm was investigated.The main factors affecting the deposition rate such as the solution composition,temperature,pH value and adding ultrasonic were explored.The results show that the optimum process conditions are CuSO4 16 g/L,HCHO 5 mL/L,NaKC4H4O6 30 g/L,Na2EDTA 20 g/L,K4Fe(CN)6 25 mg/L,pH value of 12.5-13.0 and temperature of 40-50℃.Under these technical conditions, the process has excellent bath stability.Adding ultrasonic on the process can elevate the deposition rate of copper by 20%-30%.The foam metal material with a porosity of 92.2%and a three-dimensional network structure,was fabricated by electro-deposition after the electroless copper plating.

Conductive Polyacrylonitrile Fiber Prepared by Copper Plating with L-Ascorbic Acid as Reducing Agent

Conductive polyacrylonitrile fibers were prepared by electroless copper plating under weak alkaline conditions,with L-ascorbic acid as reducing agent.The influences of CuSO_(4)·5H_(2)O,L-ascorbic acid,2,2′-bipyridine and K_(4)Fe(CN)_(6) concentration on the conductivity and mass gain percentage of the fibers were studied.The morphological structure of the fibers was characterized by scanning electron microscopy(SEM),and the mechanical properties of the fibers were analyzed through the mechanical property test.The results showed that the optimal reaction conditions were as follows:26 g/L CuSO_(4)·5H_(2)O,26 g/L L-ascorbic acid,12 mg/L 2,2′-bipyridine,7 mg/L K 4Fe(CN)6,and 38℃.The volume resistivity of the conductive PAN fibers prepared by the process was only 3.84×10^(-3)Ω·cm.

Simulation of through via bottom–up copper plating with accelerator for the filling of TSVs

Filling high aspect ratio through silicon vias （TSVs） without voids and seams by copper plating is one of the technical challenges for 3D integration. Bottom-up copper plating is an effective solution for TSV filling. In this paper, a new numerical model was developed to simulate the electrochemical deposition （ECD） process, and the influence of an accelerator in the electrolyte was investigated. The arbitrary Lagrange-Eulerian （ALE） method for solving moving boundaries in the finite element method （FEM） was used to simulate the electrochemical process. In the model, diffusion coefficient and adsorption coefficient were considered, and then the time-resolved evolution of electroplating profiles was simulated with ion concentration distribution and the electric current density.

A New Approach on the Active Treatment for Electroless Copper Plating on Glass

A new method is described for the electroless deposition of copper onto glass. Commercially available glass slide was modified with γ-aminopropyltrimethoxysilane to form self-assembled monolayer (SAM) on it. Then it was dipped directly into PdCl_2 solution instead of the conventional SnCl_2 sensitization followed by PdCl_2 activation. Experimental results showed that the Pd 2+ ions from PdCl_2 solution were coordinated to the amino groups on the glass surface resulting in the formation of N-Pd complex. In an electroless copper bath containing a formaldehyde reducing agent, the N-Pd complexes were reduced to Pd 0 atoms, which then acted as catalysts and initiated the deposition of copper metal. Although the copper deposition rate on SAM-modified glass was slow at the beginning, it reached to that of conventional method in about 5 min.

Process optimization of electroless copper plating and its influence on electrochemical properties of AB_5-type hydrogen storage alloy

The amount of Cu coating by chemical plating was investigated based on quadratic regression orthogonal experimental design being adapted to the variation law of temperature, pH value and Ni2+ concentration, and the relevant regression equation was expressed as y=2.1609+0.5295×10-3T2-0.0342P2-0.0265N2+0.0023TP+0.0020TH+0.0199PN-0.0959T+0.3814P-0.2073N. The results showed that the deposition rate augmented with the increasing in temperature, pH value and Ni2+ concentration. The experimental parameters of the optimal coating were temperature 75 °C, pH value 8.5 and Ni2+ concentration 1.2 g/L. The electrochemical tests indicated that the cycle stability increased from 60.66% to 75.58%, indicating that the treated alloy exhibited better corrosion resistance.

Preparation and characterization of molybdenum powders with copper coating by the electroless plating technique

Molybdenum powders with a diameter of approximately 3 μn were coated with copper using the electroless plating technique in the pH 12.5-13 and temperature range of 55-75℃. The optimization of the electroless copper bath was evaluated through the combination of process parameters like pH and temperature. The optimized values ofpH and temperature were found to be 12.5 and 60℃, respectively, which attributes to the bright maroon color of the coating with an increase in weight of 46%. The uncoated and coated powders were subjected to microstructural studies using scanning electron microscope （SEM） and the phases were analyzed using X-my diffrction （XRD）. An attempt was made to understand the growth mechanism of the coating. The diffusion-shrinkage autocatalytic model was suggested for copper growth on the molybdenum surface.

Electroless copper-phosphorus coatings with the addition of silicon carbide (SiC) particles

Cu-P-silicon carbide （SiC） composite coatings were deposited by means of electroless plating.The effects of pH values,temperature,and different concentrations of sodium hypophosphite （NaH2PO2·H2O）,nickel sulfate （NiSO4·6H2O）,sodium citrate （C6H5Na3O7·2H2O） and SiC on the deposition rate and coating compositions were evaluated,and the bath formulation for Cu-P-SiC composite coatings was optimised.The coating compositions were determined using energy-dispersive X-ray analysis （EDX）.The corresponding optimal operating parameters for depositing Cu-P-SiC are as follows：pH 9;temperature,90oC;NaH2PO2·H2O concentration,125 g/L;NiSO4·6H2O concentration,3.125 g/L;SiC concentration,5 g/L;and C6H5Na3O7·2H2O concentration,50 g/L.The surface morphology of the coatings analysed by scanning electron microscopy （SEM） shows that Cu particles are uniformly distributed.The hardness and wear resistance of Cu-P composite coatings are improved with the addition of SiC particles and increase with the increase of SiC content.

Ar-N_2 Shielding GTA Welding of Copper Thick Plates

The Ar-N2 gas tungsten arc(GTA) welding of 10 mm copper thick plates without preheating was investigated.The microstructure of weld metal and joints was observed and mechanical performance of weld metal was tested by using Cu-Ti welding metal with different Ti content.The Ar-N2 GTA weld of copper thick plates can eliminate the nitrogen porosities in the weld metal by adding element Ti in filler metal,which is caused by N2 gas in shield gas.The elimination degree of nitrogen porosities,the distribution of CuTiN intermetallic compound(IMC) and the mechanical performance of joints are associated with the change of the Ti content in the welding materials.And when Ti content is about 5%,nitrogen porosities is eliminated completely and the CuTiN IMC distribute dispersedly,the tensile strength and impact ductility of the joint achieve the best result,which almost reaches the lever of the base metal.

Electroless plating of copper layer on surfaces of urea-formaldehyde microcapsule particles containing paraffin for low infrared emissivity

A copper coating was deposited by electroless plating on the surfaces of urea-formaldehyde microcap- sules containing paraffin （UFP） particles. This composite microcapsule structure had low infrared OR） emissivity and maintained a constant temperature, and could be used in IR stealth applications. The eiectroless copper layer formation and its micro-appearance, and the effect of the copper layer on the IR emissivity and thermal properties of the composite microcapsules were investigated. The IR emissivity of the composite microcapsules at wavelengths of 1-14 μm gradually decreased with increasing copper mass on the surface. After formation of an integrated copper layer, the rate of IR emissivity decrease was lower. This is because the copper coating improves the surface conductivity of the UFP; a high conductivity results in high reflectivity, which leads to a decrease in IR emissivity. The lowest IR emissivity achieved was 0.68. The phase-change enthalpy of the composite microcapsules decreased with increasing amount of copper coated on the surface because of the high density of copper. When the mass increase of the UFP after electroless copper plating was about 300%, the composite microcapsules had low IR emissivity （about 0.8） and a high phase-change enthalpy （80J/g）.

Development of China's Copper Plate and Strip Industry——Part Ⅱ

In China,the upstream industries of copper processing are copper ore dressing and copper smelting industries.But China’s copper industry has seen unbalanced development between the three steps:copper ore dressing,copper smelting and processing.The industrialpattern where processing capacity is greater than smelting capacity,and smelting capacity

Development of China's Copper Plate and Strip Industry——Part Ⅰ

As a metal,copper comes in third only to iron and aluminum in terms of importance in national economy and as a non-ferrous metal,it ranks second in terms of consumption.The copper industry is a pillar of the non-ferrous metal industry in China.In 2016,the copper industry’s assets accounted for23%of the national non-ferrous industry’s total,and its income accounted for 35%.China also holds

Longitudinal corner crack of chamfered slab and optimization of mould

Chamfered mould has gradually become a new technology equipment to eliminate transverse corner crack.However,longitudinal corner crack ratio of chamfered slab was very high.Solidification microstructure was detected in the area where the longitudinal corner crack occurred.Effect of narrow face shape and taper distribution of mould copper plate on longitudinal corner crack was studied by industrial tests.Water velocity distribution in the narrow copper plate was studied by numerical simulation.On the premise of preventing cooling water from nuclear boiling,improvement measures of mould cooling process and water seam structure were put forward through heat transfer calculation.The results showed that local taper of the meniscus region of mould should be increased to prevent generation of longitudinal corner crack.Chamfering slope length of narrow copper plate should be controlled within 55 mm,and chamfering angle should be controlled at about 30°.Average water velocity should be more than 7.0 m/s.The flat and chamfering regions of narrow copper plate working face should be designed as double taper and funnel structure,respectively.The water seam in the chamfering region should preferentially choose the combined cooling structure with two holes and one slot.In order to prevent the extension of longitudinal corner crack,chamfered narrow face foot roller should be used.

Realization of high thermal conductivity and tunable thermal expansion in the ScF_(3)@Cu core-shell composites

Achieving high performances of high thermal conductivity and low thermal expansion remains a great challenge. In this study,we have designed and synthesized the ScF_(3)@Cu core-shell composites through a general electroless plating method to coat Cu on the surface of negative thermal expansion particles of ScF_(3). A spatially continuous copper network structure is formed in the present core-shell structure composites to achieve high thermal conductivity and low thermal expansion simultaneously, which is different from the conventional mixed composites. Notably, a high thermal conductivity(136.3 W m^(-1) K^(-1)) has been achieved in the ScF_(3)@Cu-40 core-shell composite with a low thermal expansion property(4.3×10^(-6) K^(-1)). The mechanism of thermal property and microstructure of the present core-shell composites are systematically studied based on different models. Our proposed approach in this study can be widely applicable to numerous advanced materials, which should simultaneously control thermal conductivity and thermal expansion properties.

Plated contacts for solar cells with superior adhesion strength to screen printed solar cells

The improvement of adhesion strength and durability of plated contacts is required for cell manufacturers to gain confidence for large-scale manufacturing. To overcome weak adhesion at the metal/Si interface, new approaches were developed. These involve the formation of laser-ablated anchor points, or grooves in the extreme case of overlapping anchor points, in the heavily doped silicon surface. When plated, these features greatly strengthen the mechanical adhesion strength of the metal. A stylus-based adhesion tester was developed specifically for evaluating the effectiveness of plated contacts to smooth silicon surfaces. The use of such a tester was also extended in this work to textured and roughened surfaces to allow evaluation of different metal contacting approaches. The adhesion strengths for various metal contacting schemes were evaluated, including screenprinted silver contacts, nickel/copper （Ni/Cu） light- induced plated （LIP） contacts for laser-doped selective emitter （LDSE） ceils, buried-contact solar cells （BCSCs）, and Ni/Cu LIP contacts formed with laser-ablated anchoring points in selective emitter （LAASE） cells. The latter has superior adhesion strength. The standard ＂peel test＂ of the industry was compared to the stylus-based adhesion testing, with the latter shown value for testing metal contacts on smooth surfaces but with caution needed for use with textured or roughened surfaces.