Copper Substrate Research Articles

Enhancing Laccase and Manganese Peroxidase Activity in White-Rot Fungi: The Role of Copper, Manganese, and Lignocellulosic Substrates

Enhancing Laccase and Manganese Peroxidase Activity in White-Rot Fungi: The Role of Copper, Manganese, and Lignocellulosic Substrates

Solar Selectivity of Silver Nanoparticles Modified Copper Oxide Nanocomposite Thin Films Prepared by Facile Chemical Oxidation Method

AbstractSilver nanoparticles modified copper oxide nanocomposite thin films (Ag‐CuO NC TFs) and pristine CuO TF were successfully synthesized on copper substrates using a chemical oxidation route. X‐ray diffractometry (XRD) characterization of Ag‐CuO NC TFs revealed the formation of monoclinic crystal structured CuO. Scanning electron microscopy (SEM) images showed a star‐like grain morphology of the Ag‐CuO NC TFs. Energy dispersive X‐ray spectroscopy (EDX) analysis ascertained the presence of anticipated elements without impurities. Fourier transform infrared spectroscopy (FTIR) investigation confirmed the presence of Ag NPs on CuO in the Ag‐CuO NC TFs. Raman spectroscopy examination indicated the presence of a spinel structure with vibrational and tetrahedral sites. UV‐Vis‐NIR reflectance analysis demonstrated that Ag‐CuO NC TFs with 2.0 wt.% Ag NPs exhibited solar absorptance of 72.39 %, thermal emittance of 4.3 %, and a highest solar selectivity of 16.83 among the prepared thin films. These results suggest that the Ag‐CuO NC TFs could be promising candidates for use as solar selective absorbers in solar thermal energy conversion devices.

The effect of multi-step cycles on the surface properties of Ni-TiO2 coatings produced by pulse current electrodeposition

ABSTRACT In this study, the Ni-TiO2 coatings were deposited on copper substrates by pulse plating. The effect of multi-step current cycles on the metallurgical properties of produced coatings was investigated. The results showed that the values of applied currents within the periods significantly affect the surface properties of all coatings. Using the negative current cycles, the surface morphologies completely changed from regular and compact to irregular, compared to the deposits that did not have a negative cycle in the coating process. Also, the surface roughness increased by 1.5 times in the best case. Applying the 8-step cycle increased the percentage of TiO2 content inside the Ni-TiO2 layer from 13.13 vol.% to 31.58%. The corrosion and wear analysis results showed that the coating applied by a 4-step cycle with a 90-second off time has the best properties. Therefore, the corrosion and wear properties were not necessarily directly related to the participation percentage of TiO2 particles. Compact morphology with high current efficiency, wide distribution of TiO2 particles (6.31 vol.%) with minimal agglomeration, low coating roughness (Ra = 0.32 µm), high hardness value (436 Vickers), and the participation of (111) plane in the preferred texture improved the corrosion and wear behaviour of the optimal coating.

Highly Robust, Pressureless Silver Sinter-Bonding Technology Using PMMA Combustion for Power Semiconductor Applications

This study presents the development of a highly robust, pressureless, and void-free silver sinter-bonding technology for power semiconductor packaging. A bimodal silver paste containing silver nanoparticles and sub-micron particles was used, with polymethyl methacrylate (PMMA) as an additive to provide additional thermal energy during sintering. This enabled rapid sintering and the formation of a dense, void-free bonding joint. The effects of sintering temperature and PMMA content on shear strength and microstructure were systematically investigated. The results showed that the shear strength increased with rising sintering temperatures, achieving a maximum of 41 MPa at 300 °C, with minimal void formation due to enhanced particle necking facilitated by PMMA combustion. However, at 350 °C, the shear strength decreased to 35 MPa due to cracks and voids at the copper substrate–copper oxide interface caused by thermal expansion mismatch. The optimal PMMA content was found to be 5 wt.%, balancing sufficient thermal energy and void reduction. This pressureless sintering technology demonstrates significant potential for high-reliability applications in power semiconductor modules operating under high-temperature and high-stress conditions.

High-speed formation of pure copper layers via multibeam laser metal deposition with blue lasers

To realize a carbon-neutral society, it is necessary to shift from gasoline-powered vehicles to electric vehicles. Electric vehicles use copper components such as coil motors and batteries for which copper joining technology is important. Additive manufacturing is one of the most essential technologies for the next generation of manufacturing. Therefore, the technology for forming pure copper layer on a pure copper substrate is important. Laser metal deposition (LMD) is one of the additive manufacturing technologies. A blue diode laser is expected to be effective in shaping pure copper parts because light absorptance of pure copper at blue light is higher than that of near-infrared light. Thus, a multibeam LMD system with the blue diode laser in which metal powder was supplied perpendicular to the processing point and multiple lasers were irradiated from the surroundings was developed for additively manufactured pure copper. In our previous study, we succeeded in forming a pure copper layer on a pure copper substrate at a speed of 1.5 mm/s with blue diode lasers. However, an increase in processing speed was necessary for industrial application. It is considered that the improvement of energy density at the processing point and the control of heat input to the powder and the substrate by lasers are essential to improve the processing speed. Therefore, in this study, we designed an optical system with ten times higher energy density and calculated the heat input to the powder to form a pure copper layer at a speed of 10 mm/s or faster.

Substrate and Step Rate Dependence Electrodeposition of Nickel–Cobalt–Molybdenum–Phosphorous Alloy for Efficient Hydrogen Evolution Reaction

Understanding the hydrogen economy involves recognizing the crucial role of water‐splitting in producing green, clean, and carbon‐free hydrogen. In that respect, the role of catalyst is very important as it enhances the reaction rate and efficiency, making hydrogen production more viable and sustainable. Herein, nickel–cobalt–molybdenum–phosphorous (Ni–Co–Mo–P) alloy has shown efficient catalysis properties for hydrogen evolution reaction (HER) in an alkaline medium. The quaternary alloys are directly grown on different substrates like nickel sheet, copper sheet, and stainless‐steel sheet by employing a simple pulse electrodeposition method. The method is conducted with a pulse interval time of 15 s at various pulse rates while maintaining the pH of 4 at room temperature. The alloy deposition is performed at a potential range from −1.5 V to −0.15 V (vs Ag/AgCl). The electrodeposition of the alloy in different substrates is first established with X‐Ray diffraction (XRD), field‐emission scanning electron microscopy (FESEM), and Raman spectroscopy. The deposited quaternary alloy exhibits the lowest overpotential of −163 mV at 10 mA cm−2 for copper substrate with a Tafel slope of 154 mV dec−1. The microcrystalline structure or amorphous nature and the rough grain surface of Ni‐Co‐Mo‐P alloys have characterized by XRD and scanning electron microscopy micrograph, respectively.

Microstructure and wear resistance of the CuSn19Ti10/diamond composite coatings on copper substrate by laser cladding

Copper and its alloys are well-known for their excellent electrical and thermal conductivity but are limited by poor mechanical strength and wear resistance. In this study, CuSn19Ti10/diamond composite coatings with strong metallurgical bonding and free from defects such as cracks and porosity were successfully fabricated on pure copper substrates using laser cladding. The process parameters included a laser power of 3000 W, a scanning rate of 15 mm/s, a spot diameter of 2.5 mm, and a lapping rate of 30 %. A comprehensive analysis of the microstructure and wear resistance was performed on coatings with 0, 2.5 %, 5 %, and 10 % (wt%) diamond content using SEM, EDS, XRD, and white light interferometry. The results indicate that the coatings consist of α-(Cu), Cu2SnTi, (Cu, Sn)Ti2, TiC, and diamond phases. The addition of diamond significantly improved both the hardness and wear resistance, with the 5 wt% diamond composite demonstrating the most notable wear resistance. This optimal composition balances diamond content, ensuring effective retention within the CuSn19Ti10 matrix, thereby reducing plastic deformation and minimizing diamond pull-out during wear.

Potentiostatic electrodeposition of copper, indium, and cadmium sulfides for CO2 electroreduction: A path toward sustainable hydrogen generation

This study focuses on the potentiostatic electrodeposition of copper indium and cadmium sulfide (CuS, In2S3, and CdS) thin films on copper substrates, aiming to develop efficient electrocatalysts for the electrochemical reduction of CO2 and sustainable hydrogen generation. Utilizing Cu Kα radiation for X-ray diffraction (XRD) analysis, the crystal structures of the electrodeposited films were confirmed, revealing well-defined crystalline phases. The films exhibited average particle sizes of 55.99 nm for CuS, 50.37 nm for In2S3, and 63.51 nm for CdS. Cyclic voltammetry and chronoamperometry were employed to optimize the deposition parameters, ensuring efficient nucleation and growth of the metal sulfide films. The electrochemical performance of the synthesized electrocatalysts was rigorously tested, demonstrating their potential for CO2 reduction under optimized conditions with the highest efficiency for CdS electrodes. Additionally, the electrodeposited CuS and CdS are of the p-type, and In2S3 is of the n-type semiconductor were studied and verified by the Mott–Schottky test. CuS, In2S3, and CdS were found to have donor and acceptor concentrations (ND) of 1.68 × 106, 1.44 × 105, and 8.9 × 105 cm3, respectively. The photoelectrochemical measurements of the electrodeposited metal sulfides were studied at ambient temperature and under illumination, providing higher photocurrent responses for CdS and demonstrating its strong potential as a photoelectrode material for CO2 reduction. This work underscores the significance of facile electrochemical synthesis methods in developing cost-effective and scalable electrocatalysts, paving the way for their integration into photoelectrochemical systems for green energy applications.

Correlation Effect on Different Temperature-Humidity Range of Highly Thermal GNP/AG/ SA Conductive Ink

The study evaluates how the resistivity and properties of the material change in response to environmental factors such as temperature and humidity, and how these changes impact its performance in various applications. In order to develop a highly thermal graphene hybridization conductive ink, a new formulation of conductive ink was formulated using graphene nanoplatelet (GNP), silver flake (Ag), and silver acetate (SA) as conductive fillers mixed with organic solvents. The batch of chemicals was converted into a powder by undergoing sonication and stirring to create a powdery state. The powder was then treated with organic solvents, specifically 1-butanol and terpineol, and mixed using a thinky mixer to form a paste. The GNP/Ag/SA hybrid conductive ink paste was then printed on copper substrates using a mesh stencil and was cured at 250°C for 1 hour. Cyclic testing had been conducted using a cyclic bending test machine and a cyclic torsion test machine in a heat chamber with different temperature-humidity. The new formulation then was characterized base on the electrical and mechanical behaviour. After the torsion and bending tests, the GNP/Ag/SA hybrid conductive ink formulation reliability was evaluated. GNP/Ag/SA hybrid conductive ink room temperature baseline and GNP/Ag/SA hybrid conductive ink after given different temperature-humidity were compared in terms of electrical and mechanical properties. Both cyclic bending and torsion testing results showed an increasing value of resistance and resistivity with every progress of bending and torsion cycle, which displays a clear trend. The results indicate that the average resistance values at all sample points either stay constant or decrease with the increasing temperature. This observation suggests that the ink's electrical conductivity remains rather stable as the temperature increases. Thus, even with rising temperatures, the ink's electrical conductivity remains stable, indicating the ink's capacity to preserve its integrity and structural qualities within a defined temperature range. Future research should focus on improving the adhesion, stability and reliability of stretchable conductive inks under various temperature and humidity conditions.

Observation of novel carbon nanocorals during the synthesis of graphene and investigations on their composition, morphological and structural properties

Novel carbon nanocorals (CNCs) are observed during the synthesis of graphene on copper substrates by thermal chemical vapor deposition, using precursor gas acetylene (C2H2) and carrier gas argon (Ar). CNCs have unique structure and investigations are carried out on structural and elemental compositions by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray excited Auger electron spectroscopy (XAES), energy dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FESEM), and high resolution transmission electron microscopy (HRTEM). The graphitic nature of the CNCs is evident from characteristic D, G, and 2D bands obtained from Raman spectrum. Elemental composition analysis by XPS shows presence of sp2 and sp3 hybridized carbon whereas XAES quantifies percentage of sp2 and sp3 hybridized carbon. FESEM micrographs show a uniform distribution of densely packed CNCs throughout the sample, and formation of groups of CNCs with distinct contours on the surface. The cross-sectional FESEM shows stacking of large number of graphene layers with dendrites. HRTEM analysis further supports observations of FESEM and elaborates structural morphology of the CNCs. Synthesis, characterization and analysis of the properties of carbon nanocorals are reported here, for the first time.

Investigating the role of graphene in the formation and stability of [formula omitted]-phase antimonene islands

Two-dimensional materials have shown tremendous potential for various technological applications. Particularly, 2D antimony exhibits high applicability in electronics, sensors, and batteries. This 2D material, known as antimonene, presents two stable phases: α (rectangular lattice) and β (honeycomb lattice), whose formation depends on the substrate where antimony is deposited. In this study, we investigated the growth of antimonene islands on graphene, forming an antimonene/graphene heterostructure. To demonstrate the significance of graphene in the synthesis of antimonene, we also studied antimony deposited on a bare copper foil similar to the one used for the graphene substrate. Antimony deposition exhibits the β phase antimonene structure when deposited on top of monolayer graphene, but not when deposited on a bare copper foil, nor on top of multilayer graphene. Additionally, we investigated the stability of the heterostructure after exposure to air. Pure antimony islands are formed when evaporated in high vacuum on top of graphene and copper substrates, and antimony atoms oxidize upon exposure to air. After annealing the sample in ultra-high-vacuum at temperatures lower than 200 °C, more than half of pure antimony is recovered and almost all oxidized antimony is desorbed from the graphene substrate. In contrast, almost none of the oxidized antimony is desorbed from the bare copper substrate, highlighting the key role of the heterostructure on the formation and preservation of the physical and chemical properties of the deposited 2D material.

Wettability/anti-icing properties of hierarchical Micro/nanostructured copper surface prepared by Micro milling and chemical etching

Ice accumulation on the metallic surface usually results in seriously economic losses, resource wastes and even hazard accidents. Superhydrophobic surfaces (SHSs) are recognized as one of the most promising candidates for water repellence and anti-icing, offering both environmental and economic advantages over the traditional methods. The ordered microstructure arrays with controllable parameters play an essential role in mechanism analysis, rational design and reproducible construction of SHSs. However, the efficient fabrication of ordered microarrays on metal substrates with high resolution and high accuracy is still fraught with significant challenges. Here, a multilevel micro/nano surface with rectangular micropillars was fabricated on copper substrate by the integration of micro milling and chemical etching, which exhibits superior superhydrophobicity with water contact angle of 171.1 ± 1.5° and sliding angle of 2.2 ± 0.7°. The developed deburring scheme makes an outstanding contribution to the in-situ removal of milling burrs generated on the top of micropillars. The variation in surface wettability with microarray geometry and etching conditions indicates that a favorable surface morphology is crucial for improving the water repellency of the surface. The results of the durability experiment and the self-cleaning test demonstrate the robust comprehensive stability of the prepared SHSs against moisture, high temperature and mechanical wear, as well as the superior fouling resistance against solid and liquid contaminants, which is mainly ascribed to the hierarchical micro/nanostructures. Moreover, the present micro/nanostructures are also demonstrated to be capable of enhancing the delayed icing performance of the copper surface, with the freezing time of a 5 μL water droplet being 519.86 ± 13.53 s. Meanwhile, the superhydrophobic copper surfaces exhibit remarkable anti-icing behavior against saline solutions, as evidenced by the freezing time of 1078.42 ± 31.24 s for a 5 μL NaCl droplet. This work provides a sustainable and high-precision approach for the fabrication of metal-based SHSs, expecting to advance the theoretical research and industrial applications of anti-icing functional surfaces.

Thermal performance of a novel hybrid heat pipe with composite heat transfer characteristics

Considering the capillary threshold of oscillating heat pipes (OHP), a novel hybrid heat pipe (HHP) was designed with channels with hydraulic diameters that alternately exceed and fall below this threshold, parallelly arrayed within a unified copper substrate. This technology attains a comprehensive heat transfer performance within the HHP, seamlessly transitioning from pure phase change heat transfer to hybrid pulsating flow heat transfer to effectively accommodate the escalating demands of heat load. Performance and visualization are used to analyze the operational characteristics of HHP. The results indicate that the HHP mainly transfers heat through the phase change in the large channels in lower heat input, while the working fluid in the small channels remains calm. Once the heat input is sufficient, the geyser boiling in the large channels and the liquid slug pulsating in the small channels jointly carry out heat transfer. Furthermore, the liquid content in the large and small channels can be adaptively adjusted to each other. The high-speed liquid in the small channels can be squeezed into the large channels to ensure the sufficient pulsating space and achieve efficient heat transfer under high heat input. In addition, the operation of the HHP can be significantly impacted by the filling ratio (FR). In the phase change stage, the FR of 47.6 % can be considered as the turning point. After transitioning to the hybrid pulsating flow stage, the HHP with low FR can get a better performance. This new type of heat pipe with gradually changing operation characteristics may be critical to solve thermal problems in variable heat load domain.

Manganese Electrochemistry in a Deep Eutectic Solvent: The Effects of KBr

AbstractThis work reports the effects of potassium bromide (KBr) on the electrodeposition of manganese on copper from a DES consisting of a stoichiometric 1:2 mix of choline chloride and ethylene glycol (Ethaline 200). The speciation of MnCl2.4H2O in Ethaline 200 has been investigated using UV–vis spectroscopy, in particular with regard to the addition of KBr to the plating bath, for which no apparent change in the Mn species was noted. This said, the physical properties of the manganese deposits themselves were found to have been considerably improved in comparison to when KBr was omitted from the bath; indeed, the actual adhesion of Mn was achieved for the first time on a copper substrate, somewhat remarkably producing a coating of some considerable thickness. Given its clear electrochemical behavior of the Mn liquid were subsequently determined via cyclic voltammetry method. A reduction in the peak current of Mn was noted on addition of KBr. The mechanism of Mn deposition has been examined via chronocoulometry and chronoamperometry. Surface analyses of Mn deposits have been conducted via SEM/EDX, AFM, and XRD, from which improvements to the Mn surface coatings in depositions performed from an electrolyte containing 0.1 M KBr were noted.

Analysis of structural, mechanical, and magnetic properties of electroplated NiAg thin films synthesized at different deposition time

By changing the electroplating deposition duration, such as 15, 30, 45, and 60 minutes, the NiAg thin films have been synthesised by electrodeposition on copper substrate at a uniform current density of 1 A/dm2 . The NiAg thin films were adhered to the substrate at a consistent electrolytic solution temperature of 30°C, and the created electrolyte's pH was maintained within a range of 7 to 8. EDAX, XRD, and SEM techniques have all been used to investigate the structural investigation of electrodeposited NiAg thin films. The FCC crystal structure can be seen by the X-ray diffraction analysis pattern, which indicates that the average crystalline size of the NiAg-coated thin films was between 31 and 64 nm.Images of coated thin films taken with a scanning electron microscope show that, even with longer deposition times, the surface morphology of electrodeposited NiAg thin films is consistent. The Vibrating Sample Magnetometer (VSM) examination was used to investigate the magnetic characteristics. With a greater saturation magnetization of 7.6930 × E-3 emu/cm3 and a lower coercivity of 92 Oe, the NiAg film deposited at 15 minutes shows a better soft magnetic nature. According to the electrochemical analyses of plated NiAg thin films, the NiAg film coated at the 60 -minute deposition period showed the lowest corrosion rate, measuring 0.047286 mm/year with a polarization resistance of 3900.9 Ω. NiAg thin films' mechanical and magnetic characteristics make them suitable to produce MEMS and NEMS based devices.

Oxidation-free silver porous sheet bonding onto a bare copper substrate in air

Oxidation-free silver porous sheet bonding onto a bare copper substrate in air

Gluconate solutions for nickel electrodeposition and nickel electroless plating

Nickel electroplating has found a wide range of industrial applications as a technique for creating protective and decorative coatings of metallic and non-metallic surfaces, protecting materials against corrosion at elevated temperatures in both alkaline environments and organic acid solutions, forming a sublayer for obtaining coatings of other metals on steel, enhancing the hardness and wear resistance of surfaces, as well as for improving solderability. Such coatings can be obtained from weakly acidic aqueous and weakly alkaline complex electrolytes. In this review, we analyze the available literature on complexation of nickel(+2) with D-gluconate ion CH2OH(CHOH)4COO‾, along with that on compositions and some technological characteristics of complex D-gluconate solutions for nickel electrodeposition and electroless plating. Thus, a corrosion-resistant smooth light-colored nickel coating, tightly adhered to a copper substrate, was obtained from an electrolyte with a pH level of 8, containing 53 g/dm3 of NiSO4 •6H2O, 44 g/dm3 of D-C6H11O7Na, 25 g/dm3 of H3BO3, 53 g/dm3 of (NH4)2SO4, and 0.5–3 g/dm3 of CO(NH2)2, at a temperature of 25 °C, a cathodic current density of 2.5 A/dm2 with a current efficiency of 96.4%. An electroless Ni-P(3–18 wt%) alloy coating on copper was obtained from a solution with a pH level of 9, containing 5–30 g/dm3 of NiSO4 •6H2O, 10–60 g/dm3 of D-C6H11O7Na, 5–40 g/dm3 of NaH2PO2 •H2O, 3 g/dm3 of HOOCCH2CH2COOH, 0.5 g/dm3 of CH3(CH2)11OSO3Na, 0.002 g/dm3 of Pb(CH3COO)2•3H2O, at a temperature of 90 °C and a deposition rate of up to 0.75 μm/min. The review also discusses methods for preparing D-gluconate electrolytes for nickel plating using sodium D-gluconate, D-glucono-1,5-lactone, and nickel D-gluconate. One advantage of D-gluconate nickel plating solutions consists in the absence of toxicity and low cost of D-gluconates.

Electrodeposition of Aluminum-Silicon Films in Chloroaluminate Ionic Liquids

Electrodeposition of aluminum-silicon films in 1-ethyl-3-methylimidazolium chloride: aluminum chloride (1:1.5 molar ratio) was studied in the presence of different silicon halides. The silicon content in the deposited films was investigated as a function of the type and the concentration of various Si precursors. Using pulse plating technique, Al-Si films with Si content between 2 - 12.9 at. % could be obtained on copper substrates at room temperature.

Adhesion of Meta-Aramid Coatings to Metal Substrates

The paper presents experimental investigations of the adhesive properties of meta-aramid coatings applied to metal substrates of different types. The increased adhesion ability of meta-aramid coatings to copper substrates was found in comparison with other metals and alloys used as structural materials. The dependence of the strength of the adhesive bond of the meta-aramid coating on the surface roughness at various concentrations of the polymer solution has been determined.

Simulation of quantum states in solid-state ferromagnetic nanostructures

Purpose of the article. Identification and analysis of mathematical expressions for the energy spectrum of charge carriers in nano-sized magnetic films of nickel and Ni-Cu (substrate), as well as NiO-Ni-Cu (substrate) structures.Methods. In this work, based on basic quantum mechanical concepts and taking into account the boundary conditions for coupled quantum wells, expressions for the energy spectrum of electrons are obtained. The ferrimagnetic properties of nickel are taken into account through the effective mass value. The solution of nonlinear equations that determine discrete energy levels was achieved by numerical methods using the Mathcad mathematical package.Results. Transcendental expressions for the energies of free charge carriers in quantum wells of ferromagnetic nickel films are obtained, and the influence of the position of nickel on the copper substrate is shown. It has been shown that the use of a copper substrate leads to an increase in the density of energy levels in the nickel nanofilm. The influence of the oxide layer on single-electron states in nanofilms of nickel and its oxide is considered within the framework of the Anderson model. Based on the numerical solution of the transcendental equations obtained in the work, the influence of the ratio of the thicknesses of a ferromagnetic metal and its oxide on the energy levels of electrons localized in the oxide layer is shown.Conclusions. The formulas presented in the work for the energy spectrum take into account the energy relief of a complex quantum well, the dimensions of the film, surface oxide, and the significant effective mass in the region of the ferromagnetic film. It has been shown that an increase in the effective mass in magnetic heterostructures leads to an increase in the electron density of states. It was found that the density of electronic states in the region of surface nickel oxide is practically independent of the thickness of the nickel film. The results and conclusions of the work can be used for theoretical prediction of the physical properties of magnetic nanostructures, in particular spintronic elements.