Copper Ions Removal from Wastewater by Electrocoagulation Using Cement-based Cathode Plates

The present work uses PEO solution to well disperse carbon fiber and identifies percolation thresholds of carbon fiber and carbon black which are used as conductive fillers.The resultant cathode plates have an average compressive strength of 27.3 MPa and flexural strength of 29.09 MPa,which demonstrate excellent mechanical properties.The Cu^(2+)removal efficiency was measured at different current densities in EC process with cement-based cathode plate,while the voltage changes were recorded.The results showed that the cement-based cathode plate operated stably and achieved 99.7%removal of 1 L of simulated wastewater with a Cu^(2+)concentration of 200 ppm at a current density of 8 m A/cm^(2)for 1 h.Characterization of floc and tested cathode plates,SEM and EDS analyses,and repeatability testing of the tested plates demonstrate the reusability of the plates,proving that cement-based plates can effectively replace metal cathode plates,reduce the cost of EC and improve the applicability of EC devices.

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 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.

Microstructure and electrical conductivity of electroless copper plating layer on magnesium alloy micro-arc oxidation coating

In order to impart electrical conductivity to the magnesium alloy micro-arc oxidation(MAO)coating,the electroless copper plating was performed.Effects of plating temperature and complexing agent concentration on the properties of the electroless copper plating layers were studied by measuring their microstructure,corrosion resistance and electrical conductivity.It was found that the optimized plating temperature was 60°C,and the most suitable value of the complexing agent concentration was 30 g/L.Under this condition,a complete and dense plating layer could be obtained.The formation mechanism of the plating layer on magnesium alloy MAO coating was analyzed.A three-stage model of the plating process was proposed.The square resistance of the plated specimen was finally reduced to 0.03Ω/□after the third stage.Through electroless copper plating,the MAO coated sample obtained excellent electrical conductivity without significantly reducing its corrosion resistance.

Development of copper coatings on molybdenum powders by electroless plating technique

Mo powders with average particle size of 3 μm were attempted to coat with copper by electroless plating technique. The effect of the solution composition and plating conditions on the electroless copper plating was studied. The uncoated and coated powders were subjected to the microstructural studies by SEM and the phases were analyzed by XRD. The results indicate that the Mo powders are coated with copper,at the same time,Mo-Cu composite powders with Cu content ranging from 15% to 85%(mass fraction) can be obtained. The optimal values of pH,HCHO concentration and temperature are in the ranges of 12-13,22-26 ml/L and 60-65 ℃,respectively. The diffusion-shrinkage autocatalytic model is suggested for the growth mechanism of electroless coating over the surface.

Electroless Plating of Carbon Nanotubes with Copper

A simple chemical method was employed to coat carbon nanotubes with a layer of copper. Due to the hydrophobic nature, large surface curvature, small diameter and large aspect ratio, it is difficult to gain continuous electroless plating layer on the surface of carbon nanotubes. In this paper, a series methods (oxidization, sensitization and activation) are used to add active sites before electroless plating, and the adjustment of the traditional composition of copper electroless plating bath and operating condition can decelerate electroless plating rate. The samples before and after coating were analyzed using transmission electron microscopy and energy-dispersive X-ray spectroscopy. The results showed that the surface of carbon nanotubes was successfully coated with continuous layer of copper, which lays a good foundation for applying carbon nanotubes in composites.

Anode oxidation of HCHO in THPED-containing electroless copper plating solution

The electrochemical mechanism of anode oxidation of HCHO in electroless copper plating solution with N, N, N′, N′-tetrakis(2-hydroxypropyl)ethylenediamine (THPED) was investigated by measuring cyclic voltammetry curves and anodic polarization curves. Three different oxidation peaks occur at the potentials of -0.62 V (Peak 1), -0.40 V (Peak 2) and -0.17 V (Peak 3) in the anode oxidation process of THPED-containing solution. The reaction at Peak 1, a main oxidation reaction, is the irreversible reaction of adsorbed HCHO with hydrogen evolution. The reaction at Peak 2, a secondary oxidation reaction, is the quasi-reversible reaction of adsorbed HCHO without hydrogen evolution. The reaction at Peak 3 is the irreversible oxidation of anode copper. The current density of Peak 1 increases gradually, that of Peak 2 remains constant and that of Peak 3 decreases with the increase of HCHO concentration. The current density of Peak 3 increases with the increase of THPED concentration and the complexation of THPED promotes the dissolution of anode copper.

Electroless copper plating process of N, N, N, N′-tetrakis (2-hydroxypropyl) ethylenediamine system with high plating rate

Electroless copper plating process of N, N, N′, N′-tetrakis (2-hydroxypropyl)ethylenediamine(THPED) chelating agent was researched comprehensively. The results indicate that plating rate decreases with the 3H2O has a bad effect on deposits quality, but 2, 2′-dipyridyl and PEG make deposits quality improve greatly. Low concentration of 2-mercaptobenzothiozole (2-MBT) increases plating rate and improves deposits quality, but decreases plating rate and worsens deposits quality when 2-MBT reaches 5 mg/L. The optimal conditions of this electroless MBT are 16.8 g/L, 16.0 mL/L, 13.3 g/L, 0.5 g/L, 5.0 mg/L and 2.0 mg/L, respectively, pH value is 12.75,bath temperature is 30 ℃. Plating rate reaches 9.54 μm/h plating for 30 min in the bath. The SEM images demonstrate that the surface of copper film is smooth and the crystal is fine.

Surface characterization and electrical resistivity of electroless plating nanocrystalline copper films on glass

Nanocrystalline copper films were prepared on the glass by electroless plating technique. The surface characterization of copper films with different deposition time was studied by field emission scanning electron microscopy(FESEM) and atomic force microscopy(AFM). The results indicate that the copper films have a(111) texture. A continuous and smooth film forms on the glass substrate at deposition times of 5 min. The surface roughness of as-deposited copper films becomes rougher with large nodules as the deposition time increases. According to Fuchs-Sondheimer(F-S),Mayadas-Shatzkes(M-S) theory and a combined model,the grain boundary reflection coefficient(R) is calculated in the range of 0.40-0.75. The theoretical analysis based on the experimental results show that the grain boundaries contribute mainly to the increase of electrical resistivity of nanocrystalline copper film compared with the film surfaces.

Electroless Plating Lead and Lead-Tin on Copper Using an Eco-Friendly Plating Bath

Copper serpentines used in gas heaters are currently coated with lead-tin alloy using hot-dip technology where copper is immersed in molten lead (98%)-Tin at about 400°C. The major drawback of this technique is the pollution resulted from lead vapors which cause much harm to the labors in the unit. The present work investigates an eco-friendly plating technique to replace the currently used technology. Electroless plating of copper samples with lead or Lead (98%)-Tin alloy is carried out from a plating bath contained lead salt, tin salt, reducing agent and stabilizing agent. The parameters affecting the coating quality such as the plating time, temperature and bath composition were optimized. The chemical analysis and coating morphology of the formed coatings are examined by XRD, SEM and EDS to reach the best bath composition as well as the best conditions to coat copper with lead or lead-tin electrolessly. The electrochemical properties of copper and copper coated samples are also examined using electrochemical impedance spectroscopy.

Unsteady MHD Casson Nanofluid Flow Past an Exponentially Accelerated Vertical Plate:An Analytical Strategy

In this study,the characteristics of heat transfer on an unsteady magnetohydrodynamic(MHD)Casson nanofluid over an exponentially accelerated vertical porous plate with rotating effects were investigated.The flow was driven by the combined effects of the magnetic field,heat radiation,heat source/sink and chemical reaction.Copper oxide(CuO)and titanium oxide(TiO2)are acknowledged as nanoparticle materials.The nondimensional governing equations were subjected to the Laplace transformation technique to derive closed-form solutions.Graphical representations are provided to analyze how changes in physical parameters,such as the magnetic field,heat radiation,heat source/sink and chemical reaction,affect the velocity,temperature and concentration profiles.The computed values of skin friction,heat and mass transfer rates at the surface were tabulated for various sets of input parameters.It is perceived that there is a drop in temperature due to the rise in the heat source/sink and the Prandtl number.It should be noted that a boost in the thermal radiation parameter prompts an increase in temperature.An increase in the Prandtl number,heat source/sink parameter,time and a decrease in the thermal radiation parameter result in an increase in theNusselt number.The computed values of the skin friction,heat andmass transfer rates at the surface were tabulated for various values of the flow parameters.The present results were compared with those of previously published studies andwere found to be in excellent agreement.This research has practical applications in areas such as drug delivery,thermal medicine and cancer treatment.

Recovery of Copper（II） and Nickel（II） from Plating Wastewater by Solvent Extraction

The solvent extraction technology, was applied to recover Cu^2＋ and Ni^2＋ from plating wastewater.Lix984N was chosen as the extractant due to-its gooff extraction performance. The influence parame-ters were examlned. The results show that the separation of Cu^2＋ and Ni＂ from sulphate medium can be realized by adjusting pH value with the help of Lix984N. For extracting Cu^2＋ and Ni^2＋, the optimal pH values are 4 and 10.5, and the maximal extraction percentages are 92.9% and 93.0%, respectively .With recovered Cu^2＋ and Ni^2＋ stripped in 170g.L^ -1 and 200 g.L^-1 H2SO4 medium, the stripping percentages of Cu^2＋ and Ni^2＋ are 92.9% and 93.0%, respectively. This method is simple and can be used to recover Cu^2＋ and Ni^2＋ from plating wastewater. And a flow sheet for separation of Cu^2＋ and Ni^2＋ is presented.

Interface repairing for AA5083/T2 copper explosive composite plate by friction stir processing

Multi-pass friction stir processing(M-FSP)was performed to repair the interface defects of AA5083/T2 copper explosive composite plates.The interface morphology and its bonding mechanism were explored.The results show that higher rotation speed and lower transverse speed produce more heat generated during FSP.The defect-free and good mechanical properties of the AA5083/T2 copper composite plate can be obtained under the condition of the rotation speed of 1200 r/min,the transverse speed of 30 mm/min and the overlap of 2/24.Moreover,M-FSP changes the interface bonding mechanism from metallurgical bonding to vortex connection,improving the bonding strength of composite plate,which can guarantee the repairing quality of composite plates.

Effect of cooling structure on thermal behavior of copper plates of slab continuous casting mold

A three-dimensional finite-element model of slab continuous casting mold was conducted to clarify the effect of cooling structure on thermal behavior of copper plates. The results show that temperature distribution of hot surface is mainly governed by cooling structure and heat-transfer conditions. For hot surface centricity, maximum surface temperature promotions are 30 ℃and 15 ℃ with thickness increments of copper plates of 5 mm and nickel layers of 1 ram, respectively. The surface temperature without nickel layers is depressed by 10 ℃ when the depth increment of water slots is 2 mm and that with nickel layers adjacent to and away from mold outlet is depressed by 7℃ and 5 ℃, respectively. The specific trend of temperature distribution of transverse sections of copper plates is nearly free of cooling structure, but temperature is changed and its law is similar to the corresponding surface temperature.

Electrochemical performance of organic film on copper surface by polymer plating of 6-mercapto-1,3,5-triazine-2,4-dithiol monosodium

The 6-mercapto-1,3,5-triazine-2,4-dithiol monosodium(TTN) compound was used to fabricate an organic film on pure copper. The polymer plating process of TTN on pure copper in Na2CO3 aqueous solution and the growth mechanism of poly(6-mercapto-1,3,5-triazine-2,4-dithiol)(PTT) film were studied by means of cyclic voltammetry. The polymer plating under galvanostatic mode at 0.05 mA/cm2 was conducted to generate PTT film on pure copper in the same electrolyte with different polymer-plating time. The film mass was determined by electronic balance and the insoluble fraction in tetrahydrofuran(THF) Is tested. The performance of organic film formed on copper surface was investigated preliminarily by potentiodynamic polarization and electrochemical impedance spectroscopy(EIS). It is found that a slight peak measured at 0 V vs SCE attributes to the oxidation of copper and generated Cu+ or/and Cu2+ to produce Cu-TTN complex,then a strong oxide peak is observed at 0.311 V vs SCE due to the polymerization of TTN for the increase of the film thickness. Electrochemical measurement results reveal that 10 min is an optimum polymer-plated time to obtain high quality film. The results of potentiodynamic polarization show that current density decreases from 1.85 μA/cm2 for bare copper to 0.168 μA/cm2 for polymer-plated copper while polymer-plated time is 10 min. The charge transfer resistances of bare copper and polymer-plated copper are 937 Ω·cm2 and 11.12 kΩ·cm2,respectively. The film capacitor for polymer-plated copper is as low as 1.82 μF·cm2. The EIS results confirm the results of potentiodynamic polarization and reveal that a homogenous and compact film is obtained by polymer plating technique.

Formation of the adakite-like granitoid complex and porphyry copper-gold deposit in Shaxi from southern Tancheng-Lujiang fault belt: A clue to the West Pacific plate subduction

On the basis of the geological and geochemical studies, including chemical analysis of bulk rocks, rare-earth and trace element studies, fluid inclusion, and S and O isotopic analyses, the authors described the geological background of the deposit in detail and presented significant proofs for the conditions of formation of the Shaxi porphyry copper-gold deposit. Compared with other large and supper-large porphyry copper deposits in China and the adjacent Cu-Au mineralized areas, the ore-forming processes and conditions were analyzed; and the possibility of forming large porphyry copper deposits in the Shaxi area was discussed. The present study indicated that the ore-forming fluid and material were mainly of magmatic origin, while meteoric water played a certain role in the ore-forming processes. Interactions between subducting and overriding plates provided a major driving force for the formation of igneous rocks and the deposition of metal elements in East China since Jurassic. Based on the geo- chemical data of the Shaxi intrusive, it is found that the copper (gold) mineralization is closely related to the genesis of adakite-like intrusive in the Shaxi area. This adakite-like intrusive was formed in the subduction environment as a result of the subduction of the West Pacific plate toward the East China continent, where there is a great potentiality to form a large porphyry copper deposit.

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.

Characteristics of High-Speed Copper Plating Films Using a Jet Flow Device

Since copper has excellent properties such as malleability and conductivity,it is widely used in the electronics field.Copper sulfate plating is expanding further in fields requiring thick deposits such as for heat dissipation boards and bumps for stress relaxation during semiconductor packaging.In this study,high-speed copper plating at 50 A/dm2 or more was achieved using a jet flow device.In addition,as a result of comparison with the low current density film,the current density had little effect on electrical conductivity and film surface structure.On the other hand,it was confirmed that the etching rate of the high current density film was greatly increased as the crystallites on the film surface became smaller than low current density film.Increase in productivity is expected due to shorter plating time enabled by film deposition at high current density.Furthermore,the increase of etching rate is expected to contribute to the suppression of undercuts that occur when removing the seed layer during wiring and bump fabrication.

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.