Pure Copper Metal Research Articles

Maillard Type Reaction for Electroless Copper Plating onto Ceramic Nanoparticles

A high demand for oxide dispersion strengthened (ODS) materials arose in wide fields of application. The electroless plating method has been presented as an elegant way to overcome different surface energies and obtain metal‐plated ceramics. However, copper electroless plating is still performed under harsh conditions with toxic and expensive reagents, including noble metals and harsh reducing agents like formaldehyde and hydrazine. To create a pure copper metal matrix in an environmentally friendly and efficient way a previously reported method is advanced in a way that naturally occurring amino acids are utilized. A screening of several amino acids leads to an improvement in phase purity and atomic efficiency. Therefore, a Maillard type reaction with lysine as amino compound is reported to show the best results in the particle coating for all ceramic nanoparticles evaluated. The metal plating results in uniform round micro particles showing a homogeneous coating. In order to obtain copper matrix composites, the prepared particles are successfully implemented in a PBF‐LB/M process after mixing with a highly conductive copper alloy. The resulting products were investigated by transmission electron microscopy, scanning electron microscopy, powder X‐ray diffraction, and optical density measurements.

Microstructure investigation and optimization of process parameters of ultrasonic welding for Al–Cu dissimilar joints using design of experiment

Ultrasonic Metal Welding (UMW) employs high-power ultrasonic vibrations to join thin metal sheets of different materials, effectively addressing the thermal damage issues associated with traditional welding methods. This study aimed to optimize the joining of thin aluminum (Al) and pure copper (Cu) metal sheets using high-power ultrasonic vibration. The investigation focused on the effect of input parameters, including time, static pressure, and welding power, on the output parameter of joint strength. The results indicated that the welding time had the most significant effect on the load obtained from the Tensile-shear test. The optimal condition was determined to be a welding time of 0.98 s, a pressure of 2 bar, and a power of 85%, resulting in a maximum predicted tensile-shear test load of 753.3 N, with an error value of 11.4% obtained from the software. Microscopic images reveal that the welding mechanism in ultrasonic welding involves continuous plastic deformation, dispersion of oxide layers, and the formation and extension of micro-bonds along the weld line.

The Effects of Surface Oxidation and H-Termination Processes Applied to Si Using Electrolytic Hydrogen Peroxide Solution to The Produced Cu/p-Si Schottky Contact Parameters

By using electrolytic hydrogen peroxide (H2O2) solution, oxidation and H-termination processes were applied to the p-Si crystal surface, which will be used for Cu/p-Si Schottky contact production, in a selective and controlled manner. Before the oxidation and H-termination processes, the p-Si(100) wafer used in this study was subjected to conventional chemical cleaning, and ohmic contact was made using pure aluminum (99.99%) metal on its back surface. The p-Si/Al with ohmic back contact was divided into three parts. A rectifying contact was immediately made to the front surface of one of them by using pure copper (99.98%) metal and called the REF (Reference) sample. The front surface of one of the remaining two p-Si/Al parts was oxidized, and the front surface of the other was H-Terminated. Rectifier contacts were made for both using pure copper (99.98%) metal and were named MIS (metal-insulator-semiconductor) and SP (surface passivated), respectively. Current-voltage (I-V) measurements of Schottky diodes of REF, MIS, and SP samples were performed at room temperature and in the dark. From the obtained data, the ideality factor (n), barrier height (Fbo), and series resistance (Rs) values of the samples were determined. As a result of the investigations, it was observed that the surface oxidation and H-Termination processes caused a decrease in the rectification factor and Fbo values of MIS and SP samples. These interesting situations were interpreted by the double-layer theory, which Bardeen predicted could exist on the surface of a semiconductor crystal and contribute to its work function.

Analysis of Antibacterial and Antiviral Properties of ZnO and Cu Coatings Deposited by Magnetron Sputtering: Evaluation of Cell Viability and ROS Production

The development and testing of antimicrobial coatings continues to be a crucial approach, considering the ongoing emergence of antibiotic-resistant bacteria and the rapid transmission of highly pathogenic viruses. In this study, three types of coatings—pure metallic copper (Cu), zinc oxide (ZnO), and a three-layer zinc oxide and copper mixed coating (ZnO/Cu/ZnO)—were deposited by magnetron sputtering on polyethylene terephthalate substrates to evaluate their antimicrobial potential using various microorganisms, including viruses. Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria were used for the assessment of antibacterial properties. Antiviral testing was performed using MS2 bacteriophage and replication-deficient Semliki Forest virus, both representing single-stranded RNA-containing viruses. The samples’ ability to cause reactive oxygen species formation was measured, and the effect on bacterial metabolic activity was evaluated. Cu-coated samples showed high inhibitory activity (>95%) against E. coli and S. aureus bacteria, as well as against tested viruses (SFV and MS2). The antibacterial and antiviral properties of ZnO/Cu/ZnO and ZnO coatings were not significant. Although ZnO/Cu/ZnO and ZnO caused inhibition of the metabolic activity of the bacteria, it was insufficient for complete bacteria eradication. Furthermore, significant reactive oxygen species (ROS) production was detected only for single Cu-coated samples, correlating with the strong bacteria-killing ability. We suppose that the ZnO layer exhibited a low release of Zn ions and prevented contact of the Cu layer with bacteria and viruses in the ZnO/Cu/ZnO coating. We conclude that current ZnO and Cu-ZnO-layered coatings do not possess antibacterial and antiviral activity.

Cytotoxic Activity of CuO NPs Prepared by PLAL Against Liver Cancer (Hep-G2) Cell Line and HdFn Cell Lines

A simple physical technique was used in this study to create stable and cost-effective copper oxide (CuO) nanoparticles from pure copper metal using the pulsed laser ablation technique. The synthesis of crystalline CuO nanoparticles was confirmed by various analytical techniques such as particle concentration measurement using atomic absorption spectrometry (AAS), field emission scanning electron microscopy (FE-SEM), the energy dispersive X-ray (EDX), and X-ray diffraction (XRD) to determine the crystal size and identify of the crystal structure of the prepared particles. The main characteristic diffraction peaks of the three samples were consistent. The corresponding 2θ is also consistent, and the cytotoxicity of the nanoparticles was also investigated. After 24 hours of exposure, the percentage of cytotoxicity was calculated. The maximum toxicity of Hep-G2 was 37.81% at the maximum concentration of (500) µg mL-1 after 24 hours of exposure. Also, the maximum toxicity of the normal cell line was 27.85% at a maximum concentration of (500) µg mL-1.

An experimental investigation of the fluid accessibility of preconditioned sulphide copper ores

Copper is crucial for a transition to a low-carbon economy and for energy-efficient technologies. In nature, can be mostly found in minerals as combination with iron and sulphide and its conversion into pure copper metal is frequently produced through comminution and concentration techniques. The use of hydrometallurgical methods has been successfully applied in the treatment of oxides and secondary sulphides, but its industrial applicability to primary ores has been very limited. The “accessibility” of the minerals is a key factor for their recovery through leaching, with surface grains being the most easily leached. This paper presents results from controlled blasting tests to investigate the effect of stress-induced damage on fluid penetration into copper ore samples. The results show that preconditioning by energetic loading can extend the Fluid Penetration depth by an average of 1.09 mm and up to 7 mm, compared to the 0.56 mm average of samples without conditioning. The experiments demonstrate that stress-induced fractures create extended fluid pathways, increasing the number of grains that can be potentially dissolved, and the presence of statistical outliers in the analysis shows that these induced microfractures can have a significant impact on fluid accessibility.

Design of a RGB-Arduino Device for Monitoring Copper Recovery from PCBs

The mobile phone industry, one of the fastest advancing sectors in production over the last few decades, has been associated with a high e-waste generation rate. Simultaneously, a high demand for the production of new electronic equipment has led to the scarcity of certain metals. In this context, many recent studies have focused on recovering certain metals from e-waste through the use of bioprocesses. Such recovery processes are based on the action of microorganisms that produce Fe(III) as an oxidant, in order to leach the copper contained in printed circuit boards. During the oxidation-reduction reaction between Fe(III) and metallic Cu, the color of the solution evolves from an initial reddish color, due to Fe(III), to a bluish-green color, due to the oxidized Cu. In this work, a hardware-software prototype is developed, through which the concentrations of the key analytes—Fe(III) and Cu(II)—can be determined in real time by monitoring the color of the solution. This is achieved through the use of a non-invasive system, taking into account the aggressiveness of the solutions used for the bioprocessing of electronic components. In the work presented herein, the evolution of the solution color during the bioprocessing of two different types of waste (i.e., electric cable and mobile phones) is analyzed and then compared with the results obtained for pure metallic copper. The results are validated through comparison of the predicted results with the outcomes of conventional procedures, including offline sampling and analysis of Cu(II) and Fe(III) through atomic absorption and UV-VIS spectroscopy, respectively. The developed monitoring system allows an algorithm to be designed that can fit the evolution of analyte concentrations without the need for sampling or the use of complex, tedious, and expensive analytic techniques. It is also worth noting that the monitoring system is not in direct contact with the solution (which is highly aggressive for the processing of electronic equipment), making the system more durable than classic sensors that must be submerged in the solution. The real-time nature of the obtained information allows for the development of control actions and for corrective measures to be taken without affecting the biomass involved in the process.

Study on plasma cleaning of surface contaminants on pure copper

To demonstrate the relationship between the type of working gas and the efficiency of plasma cleaning, the kinetic energy of the incident ions was controlled by adjusting the bias, and the effect of different ion sources on the sputtering yield under the same bias was compared. The plasma flow generated by glow discharge was used to clean the sample surface to evaluate the plasma cleaning efficiency. Scanning electron microscope (SEM), x-ray photoelectron spectroscopy (XPS), x-ray Powder Diffraction (XRD), Ultraviolet-visible Spectrophotometer (UV), and Surface Profiler were used to characterize the surface morphology, element types, phase composition, specular reflectance, and three-dimensional (3D) morphology before and after plasma cleaning. The results show that the sputtering yield increases with the increase of bias, and when the bias value is lower than 400 V, the mass of the samples has almost no change before and after cleaning. It takes more energy to remove the surface oxide than the pure metal copper. The results also show that argon plasma has a better effect on removing pollutants on the sample surface than nitrogen plasma. However, a long time of plasma cleaning is often accompanied by re-deposition. The changes in copper reflectance induced by plasma cleaning are also discussed.

Significance of strain rate in severe plastic deformation on steady-state microstructure and strength

The microstructure and mechanical properties of materials saturate to steady states after severe plastic deformation (SPD). Despite the well-known effect of temperature on the steady-state microstructure, there is no general agreement on the significance of strain rate and the applicability of the Zener-Hollomon parameter in this regard. In this study, several pure metals (aluminum, copper, titanium, and iron) and a Cu–30Zn (wt%) brass alloy have been processed by a high-speed high-pressure torsion (HPT) equipment with controllable rotation speeds in the range of 0.06–60 rpm. It is found that crystallite/grain size, dislocation density, microhardness and shear stress at the steady state are reasonably rate-independent for the von Mises strain rates in the range of 0.004–20 s−1. Because both rates of grain refinement and of dynamic recrystallization are proportional to the strain rate, it is suggested that their balance, which determines the steady state, is rate-independent.

An Early Egyptian Copper Basin: Characterization and Case of Warty Corrosion

The work aims to study the manufacturing technique, microstructure features, and morphology and mechanism corrosion of a hammered copper basin belonging to one of the early metallurgy ages in ancient Egypt ( the old kingdom). The examination and analysis were carried out by USB microscope, polarized light microscope, scanning electron microscope equipped energy dispersive X-ray and X-ray diffraction. The results revealed that the basin was made of pure copper metal and manufactured as one piece by a hammering method. Metallographic examination showed a recrystallized microstructure, composed by the mechanical process for manufacturing the basin throughout hammering and annealing. The cylindrical body (rim) was in well- preserved state although it was covered with a thin layer of usual green corrosion products. The pustules of warty corrosion were formed on the inner surface of the rim. The curly shape of malachite corrosion were also observed. The morphology and mechanism of warty corrosion were presented and the difference between this type and the pitting corrosion was discussed. The characterization of the basin contributed to understanding and evaluating the preservation condition, which contributes to choosing the appropriate conservation process.

Treatment of copper converter slag with deep eutectic solvent as green chemical.

Industrial copper slag is among the most important wastes to be evaluated in terms of containing valuable metals and the amount of waste approaching 30 million tons per year. Therefore, in this study, it was aimed to propose a feasible route for copper and zinc recovery from copper converter slag (CCS) by using choline chloride (ChCl) based deep eutectic solvent which is applied on this type of slag for the first time. During the leaching experiments with the pure ChCl-2urea mixture, temperature (25-95°C), leaching duration (2-72h), and pulp density (1/10-1/40g/mL) were selected as the parameters to be investigated for Cu and Zn extraction. After the experimental results, the optimized conditions for the ChCl-2urea leaching process, which gave 89.9% Cu and 65.3% Zn extraction was found at 48h, 95°C, 1/20g/mL pulp density with 600rpm stirring speed. It is noted that the iron dissolution ratio is very low (max. 4.7%) under the selected conditions. At the end of the iron cementation stage, the total recovery efficiency as a pure metallic copper was 63%. The calculated activation energy for the dissolution of the copper and zinc from CCS is 8.86kJmol-1 and 14.48kJmol-1, respectively.

Melting phenomena of Cu0.25 Ni0.75 bimetallic alloy: A molecular dynamics approach

Alloys of transition metals draw attention from the scientific community due to the interesting physical and thermal behaviour they exhibit over their pure metal components. Atomic Molecular Dynamics Simulations on Pure copper (Cu) metal, nickel (Ni) metal and their Ni rich alloy (Cu0.25 Ni0.75) have been carried out using the second nearest neighbour modified embedded atom potential parameters to investigate on the melting phenomena of the Ni rich alloy. The variation of average potential energy with respect to temperature is used to estimate the melting point temperature. Various other analyses such as; specific heat, mean square displacement of atoms and self-diffusion coefficients of atoms have been calculated in order to determine the exact transition region in the metals and to mark the melting point temperatures. The results show that the melting temperature of the Ni rich alloy is more as compared to its pure components (Cu and Ni). For the alloy, the calculated melting temperature is 2430 K± 5 K, whereas that of the pure Cu metal is found to be 1900 K± 5 K and pure Ni metal is 2370 K± 5 K. The study shows that the alloy under investigation is comparatively more thermally stable than pure Cu and Ni.

Corrosion behavior of copper, tin, and bronze CuSn14 in acid rain solution

AbstractThe corrosion behavior of copper, tin, and bronze CuSn14 is studied in simulated acid rain (pH 4.5) by electrochemical techniques, cyclic voltammetry and electrochemical impedance spectroscopy. The potentiodynamic formation of anodic oxide film on copper and tin is described in terms of high‐field model. Cyclic voltammetry shows that dissolution of bronze is higher than of pure copper metal in acid rain. Electrochemical impedance spectroscopy data reveal that oxide films formed on copper and tin have a higher resistance and suppressed diffusion process through the surface layer than the oxide film formed on bronze CuSn14 at the same conditions.

Simulation between Soldering and Brazing of Copper at 450 Temperature by Zn-Sn Fillet Alloy

In this research, a comparison between Soldering and Brazing welding of pure copper metal using a (Zn-Sn) alloy filler was numerically investigated. The welding operations on the eight pieces with dimension (30mm x 20mm x 2mm) were carried out used (Auto Desk Inventor program) to prepare four samples, while the simulation was conducted on these samples by utilized the (COMSOL Multiphysics 4.1 program) to investigate the heat distribution and tensile stress. The simulation study results showed that the thermal distribution of Soldering welding was less than that of the Brazing welding in the area between (40-60 mm) and the maximum temperature of Soldering welding in that region was (405 °C), while the highest temperature for the Brazing welding in the same area reaches to (449 °C). The total displacement of the Soldering welding was up to1.9 x10-7 mm greater than that of the Brazing welding when the shedding stress equal to 5x104 N/ m2

Grand-Expert spectrometer for metal analysis: current status and analytical capabilities

This paper presents the characteristics of the modern Grand-Expert spectrometer for the analysis of metals and alloys. The spectrometer has an updated optical scheme and a new spectrum analyzer to solve a wide range of analytical tasks. The analytical capabilities of the spectrometer were investigated for the analysis of steels and high-purity copper and aluminum as an example. For each of the bases, the updated optical scheme made it possible to realize new opportunities for controlling the homogeneity of the sample material and the presence of micro-inclusions on the sample surface and for determining low impurity contents in the pure metal bases. The spectrometer uses a modern semiconductor spark generator with adjustable frequency, current intensity, and duration of individual spark pulses. Spectra of metal samples for individual spark pulses were obtained in real time for the investigated sample. The operation of the spectrometer in different modes and with different exposure times was tested to select the optimal parameters of calibration characteristics. Computer control provides full synchronization of the generator mode setting, argon feeding, and spectrum registration. For steels, we selected sparking modes with high stability of spectral line intensities and analyte concentrations, and for pure metals (copper and aluminum), modes providing low detection limits of impurity elements and good stability of the results.

Experimental study of the influence of operational and geometric variables on the powders produced by close-coupled gas atomisation

The effect of several operational and geometric variables on the particle size distribution of powders produced by close-coupled gas atomisation is analysed from a total of 66 experiments. Powders of three pure metals (copper, tin and iron) and two alloys (bronze Cu-15 wt% Sn and stainless steel SS 316 L) have been produced. Nitrogen, argon and helium were used as atomising gases. It is shown that the gas-to-metal ratio of volume flow rates (GMRV) is more relevant than the ratio of mass flow rates (GMR) in order to analyse the effect of atomisation variables on the particle size. Kishidaka's equation, originally proposed for water atomisation, is modified to predict the median particle size in gas atomisation. The accuracy of the new equation is compared with that of Lubanska, and Rao and Mehrotra. Kishidaka's modified empirical correlation is the most accurate in predicting the median particle size of the powders produced in this work. The morphology of the produced powders is studied by scanning electron microscopy (SEM) and it is observed that the melt superheat can play an important role in the aggregation of fine particles (< 10 μm), which increases the fraction of large particles (> 100 μm).

Kinetics of the reaction of SiO2 and MnO reduced by C in molten copper with carbon saturated

In order to study the effect of matrix metal species on the kinetics of the reaction of Si02 and MnO reduced by C in molten copper with carbon saturated, the experiment, in which a preliminary slag with the composition of 38%CaO-38%SiO2-20%Al2O3-2%MnO-2%MgO that was placed in a graphite crucible and reacted with pure metallic copper at 1450°C under the atmosphere of pure CO, was carried out. The kinetics of both the reactions of Si02 and MnO in molten slag reduced by C in molten copper with carbon-saturated (2[C]sat.in Cu + (SiO2) = 2CO(g) + [Si]in Cu and [C]sat.in Cu + (MnO) = CO(g) + [Mn]in Cu) have been studied by studying the changes of the concentration of Si and Mn in molten copper with carbon-saturated, and the reaction order and reaction rate constant of the two reactions have been obtained. The results show that: (1) The reaction of SiO2 reduced by C is 0.5th order reaction while it is -0.5th order reaction for MnO; (2) The reaction rate constant of the reduction of SiO2 reduced by C in molten copper with carbon-saturated is 7.50×l0−6 mass%0.5·s−1, while that of MnO reduced by C in molten copper with carbon-saturated is 5.52x10−6 mass%1.5·s−1; (3) In this study, the reactions of SiO2 and MnO reduced by C in molten copper with carbon-saturated is a slow reaction and the time for the reaction equilibrium is more than 22 hours.

Bee pollen extract as an eco-friendly corrosion inhibitor for pure copper in hydrochloric acid

Herein, bee pollen extract (BPE) was assessed for its performance as a green inhibitor of copper corrosion in acidic media. Gas chromatography mass spectrometry was used to identify the major components of BPE. Multiscale testing techniques, i.e. weight assessment, potentiodynamic polarisation tests, and electrochemical impedance spectroscopy, were employed to explore the corrosion properties of pure copper specimens in 1 M HCl with 0–7 g/L BPE. The adsorption of BPE on the copper surface fitted a Langmuir-type isotherm. BPE behaves as a mixed-type inhibitor that effectively decreases the corrosion of pure copper metal surfaces in 1 M HCl. Increasing the concentration of BPE increases its inhibition efficiency; at 7 g/L BPE, a high inhibition efficiency of 94.5% was attained. Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy, and scanning electron microscopy were employed to analyse the copper surface. The inhibitive properties of BPE on pure copper corrosion are attributed to the adsorption of antioxidants and phenolic compounds on the copper surface. This study provides insight into the efficiency of BPE as a potential corrosion inhibitor of copper in acidic environments.

Some investigations on surface quality indicators for OHNS die steel machined with suspended powder EDM process

The study focuses on the evaluation of surface quality characteristics of oil hardened non shrinking die steel surface machined with suspended powder electrical discharge machining process. Pure copper metal is used as an electrode material, and tungsten powder is used as suspended medium for the purpose. Machining experiments were carried out by varying one parameter at a time. After each test, the machined surface is analysed for evaluating its surface roughness and microhardness values. It is found that combination of 4 A gap current, 12 μs pulse on span and 7 μs pulse off span will result in optimum surface quality indicators for the SPEDM process. Also, dry sliding wear experiments were carried out on the machined surface to evaluate the frictional force and coefficient of friction. Spectroscopic analysis and energy dispersive X-ray diffraction analysis on the machined surface indicate a considerable rise in carbon and tungsten content on the recast white layer of the machined surface. Scanning electron microscopic analysis of the machined surface revealed the presence of compounds of tungsten on the recast white layer. Also, micro-cracks were observed on the machined surface which is due to higher gap current setting during EDM process.

Some investigations on surface quality indicators for OHNS die steel machined with suspended powder EDM process

The study focuses on the evaluation of surface quality characteristics of oil hardened non shrinking die steel surface machined with suspended powder electrical discharge machining process. Pure copper metal is used as an electrode material, and tungsten powder is used as suspended medium for the purpose. Machining experiments were carried out by varying one parameter at a time. After each test, the machined surface is analysed for evaluating its surface roughness and microhardness values. It is found that combination of 4 A gap current, 12 μs pulse on span and 7 μs pulse off span will result in optimum surface quality indicators for the SPEDM process. Also, dry sliding wear experiments were carried out on the machined surface to evaluate the frictional force and coefficient of friction. Spectroscopic analysis and energy dispersive X-ray diffraction analysis on the machined surface indicate a considerable rise in carbon and tungsten content on the recast white layer of the machined surface. Scanning electron microscopic analysis of the machined surface revealed the presence of compounds of tungsten on the recast white layer. Also, micro-cracks were observed on the machined surface which is due to higher gap current setting during EDM process.