Copper-nickel Alloys Research Articles

Evolution mechanism of element Ni on matrix, surface and interface during static soaking of copper-nickel alloy

This article uses XRF, WLI, SEM, EDS, XPS and EIS techniques to characterize the surface element segregation and the state of corrosion product films under different periods of artificial seawater immersion. The research results show that when the film is intact, a uniform Ni-rich layer is formed below the film due to the preferential dissolution of Cu elements, which weakens the segregation degree of Ni elements on the surface of the substrate. At the same time, Ni elements enter the film in the form of doping, which increases the resistance of the film. When the film layer is damaged, the Ni-rich layer between matrix and surface will be rapidly converted to NiO, the enrichment state of Ni element will be destroyed, and the segregation degree will be increased. However, NiO only plays a temporary protective role, and it is easy to hydrolysis into loose Ni (OH)2, resulting in the film layer fall off. After the matrix is exposed, the Cu element is preferentially dissolved again, and the nickel-rich layer is re-formed on the substrate surface.

Machine Learning and Taguchi Techniques for Predicting Wear Mechanisms of Ni-Cu Alloy Composites

Nickel-Copper alloys hybrid composite was formed in an induction furnace set up on a sand substrate. With different percentages of Al2O3 (3, 6, 9 and 12 wt.%) and TiO2 (constant 9wt.%) reinforcements, the goal is to examine the wear behavior and friction coefficient of Ni-TiO2-Al2O3. The factors considered for the wear analysis were sliding distance (1500, 1000, and 500 m), applied load (25, 50, and 75 N), and sliding velocity (1.46, 2.93, and 4.39 m/sec). The pin-on-disc equipment is utilized to perform different wear tests are carried out using in accordance with the Taguchi L27 orthogonal array. The machine learning used to correlate between actual and anticipated values for both metrics is strong, with a reasonable error margin. The Mean Squared Error (MSE) for the wear rate was 0.1025 (10.25%) in the Linear Regression model and 0.2390 (23.89%) in the Random Forest model. Regression analysis determined the impact of several parameters on wear rate, whilst machine learning approaches expanded the evaluation of wear rate and coefficient of friction beyond experimental data. The findings demonstrate the effectiveness of combining Taguchi methods with machine learning to accurately anticipate wear mechanisms in Ni-Cu alloy composites.

Corrosion behavior and strengthening mechanism of Ni-Cu alloy coating on NdFeB magnets

In this paper, the pulse-reverse current electroplating technique was utilized to deposit nickel–copper (Ni-Cu) alloy coatings on the surface of neodymium magnets (NdFeB). Compared with the nickel (Ni) coating, the corrosion resistance of the nickel–copper alloy coating has been significantly improved. Additionally, the results show that alloying can effectively prolong the incubation period of pitting nucleation and improve the self-healing ability of coating. The structure and microstructure of the coating show that the surface of the nickel–copper coating is flat and the grains preferentially grow along the (111) close-packed surface, which also makes the coating to have higher densification and significantly reduces the number of self-corrosion sites and corrosion tendency of the coating. The lower binding energy copper(I) oxide (Cu2O) produced by nickel–copper coatings at the initial corrosion stage can reduce the formation of metal cation holes and prolong the incubation period of pitting corrosion. After pitting formation, the corrosion products copper(I) oxide and dicopper chloride trihydroxide (Cu2(OH)3Cl) of copper (Cu) in the pitting hole have a certain hindrance to corrosion and are conducive to promoting passive reconstruction, which is an important reason for higher self-healing ability and higher corrosion resistance of the nickel–copper alloy coating.

Electrosynthesis of tunable NiO/CuO-printed circuit board electrodes for glucose sensing

In this research work, a copper-based printed circuit board (Cu-PCB) was used as an electrode substrate. Alloyed copper-nickel oxides were synthesized on the surface of the Cu-PCB electrode by the two stages: In the first step, the electrodeposition of copper-nickel alloy on the surface of the Cu-PCB electrode was carried out by cyclic chronopotentiometric method (8 cycles) at the optimized conditions. In the second step, the Ni/Cu-PCB electrode was immersed in 1 M NaOH electrolyte solution, followed by the electrochemical synthesis of the alloyed copper-nickel oxides by repetitive cyclic voltammetry (40 cycles) and subsequently, the NiO/CuO-PCB electrode was obtained. The surface structure and morphology of NiO/CuO-PCB and Cu-PCB electrodes were comparatively investigated by SEM, EDX, and XRD techniques. Moreover, the electrochemical behavior and electrocatalytic properties of NiO/CuO-PCB electrode have been effectively investigated. To study the electrocatalytic efficiency of the NiO/CuO-PCB electrode, the measurement of glucose as a biological target was studied by cyclic voltammetry (CV) and amperometry approaches as well. The limit of glucose detection (LOD) and sensitivity of the proposed method in glucose assay were calculated as 5.4 and 1.1 µM, and 118.14 and, 112.08 mA/M by CV and amperometry approaches, respectively. Two-segment calibration graphs were found over the range 1.4–120 mM by CV, and 0.14–180 mM by hydrodynamic amperometry techniques. The fabricated sensor was successfully used to measure glucose in blood serum and human plasma samples.

Rotary Electrodeposition of High-Strength Nanotwinned Copper Foils

Due to the 2050 Net Zero Emissions becoming a major goal worldwide, electric vehicles have emerged as the future mainstream products. Among them, copper foils play a crucial role as the anode current collector in lithium-ion batteries (LIBs). Enhancing the strength and decreasing the thickness of copper foil are both important factors improving the lifespan of LIBs. The thickness of Cu foils can be reduced by rolling copper sheets, but it is challenging to achieve the required thinness below 10 micron for electronic applications. Direct current electroplating not only effectively increases the deposition rate but also reduces costs for thin Cu foils. In this study, we utilized a rotary direct current Cu-Ni co-electroplating method to enhance the mechanical strength of nanotwinned copper. The ultimate tensile strength (UTS) of nanotwinned copper-nickel alloy reached over 847.3 MPa (an increase of approximately 12.6 % compared to the maximum UTS of nanotwinned copper, which was 752.8 MPa) while maintaining excellent electrical conductivity similar to nanotwinned copper. Through potentiostat analysis, it was discovered that nickel ions inhibit copper growth, causing the reduction potential of copper to shift negatively, resulting in a decreased deposition rate and increased twin density. The nickel content, measured by ICP-MS, was found to be 0.467 ppm, suggesting that nickel acts as an impurity that refines grain size in copper foils. Therefore, this method not only significantly improves the strength of copper foils but also maintains low electrical resistance and low-cost characteristics. It provides a new material option for the anode current collector of the next-generation LIBs. Figure 1

Corrosion of Copper-Nickel Alloys in Seawater-Based Electrolytes

Copper nickel materials are used for their corrosion resistance due to the protective film that forms in seawater. The development of this film over time depends on the exposure condition, and it is critically important to understand the aging process for CuNi components used in marine systems to ensure passivity under sulfide contaminated conditions. Here we study the formation of the protective film over time and its effect on corrosion performance. Electrochemical impedance spectroscopy (EIS) measurements during exposure are used to develop a model of film growth on CuNi 70/30 alloys. These electrochemical measurements are coupled with surface analytical techniques such as glow discharge-optical emission spectroscopy (GD-OES) and X-ray photoelectron spectroscopy (XPS) to characterize the composition of the surface oxide. GD-OES results show that as the protective layer forms, nickel mainly remains at the metal surface and the outer layers are copper enriched oxides and chlorides. There is also incorporation of various elements from the seawater within the film. The rate of this film growth is correlated to the resulting decrease in corrosion rate. Different exposure conditions, such as under flow, are investigated.The translation of these protective film mechanisms to additively manufactured CuNi materials is also of interest, to ensure similar performance with these materials. Evaluating corrosion performance of these newly developed materials involves careful comparison to existing knowledge of film growth and potential for breakdown.

Synthesis of Copper–Nickel and Iron–Nickel Alloys by Hydrogen Reduction of Mixtures of Metal Oxide Powders

The vast majority of metals production is based on the use of carbon as a reductant and/or a heating fuel. This results in a large amount of carbon dioxide emissions and should be minimized to limit global warming. In this study, powders of copper–nickel alloy and iron–nickel of varying compositions were produced in a single step by reduction of mixtures of Cu2O-NiO and Fe2O3-NiO powders, respectively, using hydrogen as a reductant. Reduction was performed in a horizontal tube furnace at 700 °C for 45 min. All processing was in the solid state and alloys were produced directly from elemental metal oxides. Exhaust gases were analyzed using a gas analyzer to measure the water content to track the progress of the reduction. Reduction was declared complete when the water content in exhaust gases matched the level before hydrogen was introduced. Both copper–nickel and iron–nickel alloys were produced successfully. X-ray diffractometry confirmed the absence of oxides in the product and the presence of solid phases in agreement with the relevant binary phase diagram. Energy-dispersive X-ray spectroscopy in a scanning electron microscope showed macroscopic homogeneity at the expected composition for each powder mixture directly after reduction, with microscopic fluctuations of the order of several mass percent, within the limits of fluctuations observed following typical casting processes. These promising results warrant further investigation to apply this concept to more chemistries and to scale up the process to a pilot scale.Graphical

CuNi alloy anchored on dual-substrate TiOx/N-doped carbon nanofibers as a bifunctional electrocatalyst for rechargeable zinc-air batteries

Development of non-noble metal-based electrocatalysts to enhance the performance of zinc-air batteries (ZABs) is of great significance, but it remains a formidable challenge due to their poor stability and activity. Herein, a bifunctional CuNi-TiOx/NCNFS electrocatalyst, featuring with electron-rich copper-nickel (CuNi) alloy nanoparticles anchored on titanium oxide/N-doped carbon nanofibers (TiOx/NCNFS), is constructed by a dual-substrate loading strategy. The introduction of TiOx has led to a significant increase in the stability of the dual-substrate. The strong electronic interaction between CuNi and TiOx strengthens the anchoring of active metal sites, thus accelerating the electron transfer. Theoretical calculations unclose that NCNFS can regulate the charge distribution of TiOx, inducing the charge transfer from NCNFS → TiOx → CuNi, thereby reducing the d-band center of Cu and Ni, which is beneficial to the desorption of intermediate oxide species of the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). Therefore, CuNi-TiOx/NCNFS delivers a remarkable bifunctional performance with a low OER overpotential of 258 mV at 10 mA cm−2 and an ORR half-wave potential of 0.85 V. When assembled into ZABs, CuNi-TiOx/NCNFS shows a low potential gap of 0.64 V, a higher power density of 149.6 mW cm−2 at 330 mA cm−2, and an outstanding stability for 250 h at 5mA cm−2. This study provides a novel approach by constructing dual-substrate to tune the electronic structure of active metal sites for efficient rechargeable ZABs.

Influence of anodic treatment of a copper-nickel alloy in a eutectic mixture of choline chloride and urea on the surface morphology and electrocatalytic behavior in the hydrogen evolution reaction

For the first time, we investigated the process of potentiostatic anodic treatment of the surface of a copper (≈55%)-nickel alloy in a eutectic mixture of urea and choline chloride (reline), which is a typical representative of a new generation of ionic liquids, deep eutectic solvents. The anodic behavior of the alloy in the used solvent was characterized by cyclic voltammetry, and the nature of the electrochemical dissolution reactions of individual components of the alloy corresponding to several anodic current waves registered in voltammograms was determined. It was established that the anodic dissolution of the alloy occurs under conditions of salt surface passivation due to the formation of a layer of poorly soluble products of the electrode reaction. It was shown that under conditions of prolonged (150 min) potentiostatic polarization of the alloy in reline for various values of the electrode potential (in the range from 0.1 to 1.7 V relative to the Ag reference electrode), the chemical composition of the surface remained unchanged (i.e., there was no selective etching of individual components of the alloy), but an evolution of surface morphology patterns was observed, the specific type of which depended on the value of the applied potential. Anodic treatment of the Cu-Ni alloy in the reline solvent at any of the investigated anodic potentials led to an increase in the surface roughness coefficient, and electrochemical polishing did not occur. Analysis of kinetic data related to the hydrogen evolution reaction on the surfaces of reline-treated copper-nickel alloys in a 1 M NaOH aqueous solution showed a significant increase in exchange current density. This indicates enhancement of electrocatalytic activity compared to the untreated surface. The observed effect is likely associated with an increase in the true surface area of the alloy available for electrochemical reaction and an increase in the surface concentration of electrocatalytic sites resulting from the anodic dissolution of the alloy. The obtained results can be used in the development of highly efficient and relatively inexpensive electrocatalysts for hydrogen energy.

Inhibition of metal corrosion in neutral aqueous solutions by succinic acid salts

The adsorption, protective and passivating effect of sodium succinate and a blend of sodium alkenylsuccinates SKAP-25 on the oxidized surface of copper, copper-nickel alloy MNZh5-1 and low-carbon steel St3 in a neutral chloride solution were studied. The free adsorption energy (–ΔG0a,max) values for all studied metals suggest chemisorption interaction of these organic anion with oxidized metals surfaces: (–ΔG0a,max) for St3 60.2 kJ/mol, for copper 77.4 kJ/mol and for copper alloy 89.3 kJ/mol. Sodium succinate is able to stabilize the passive state of the MNZh5-1 alloy in a neutral chloride buffer solution. On copper, copper alloy and St3, protection against local depassivation is observed up to a certain concentration, above which the protective properties of sodium succinate decrease. Polarization measurements on the air-oxidized surface of low-carbon steel St3 showed that sodium succinate and SKAP-25, as well as their compositions with 2-mercaptobenzothiazole (2-MBT), are able to reduce anodic dissolution currents and increase the local depassivation potential. Corrosion tests of St3 in a 0.01 M NaCl solution proved the advantage of using the composition of SKAP-25 with 2-MBT (7.1:1) in comparison with the individual compound: the degree of protection of St3 at Cinh=7 mmol/L is 99%, and sodium succinate+SKAP-25 (1:1) at Cinh=7 mmol/L is Z=93%.

The effects of electrolyte composition and deposition voltage on the copper-nickel alloy micropillars fabricated by Jet ECD

With the rapid development of micro electronic component technology, higher requirements are put forward for high performance and high precision manufacturing process. In this paper, copper-nickel alloy micropillars were manufactured by jet electrochemical deposition (Jet ECD) technology with high deposition rate, aiming to provide an effective material and process solution for the manufacture of micro-thermocouples and other components. By optimizing the process parameters such as electrolyte composition, pH value and deposition voltage, the homogeneous deposition of copper-nickel alloy micropillar was realized. The cross-section morphology and elementary composition of the deposition micropillars were characterized in detail by using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results show that the adjusted formula and process parameters can stably manufacture copper-nickel alloy micropillars with a nickel-copper ratio (close to 0.8), and compact, void free microstructure.

Synergistic Effect of P and Co Dual Doping Endows CuNi with High-Performance Hydrogen Evolution Reaction.

The rational design of highly active and durable non-noble electrocatalysts for hydrogen evolution reaction (HER) is significantly important but technically challenging. Herein, a phosphor and cobalt dual doped copper-nickel alloy (P, Co-CuNi) electrocatalyst with high-efficient HER performance is prepared by one-step electrodeposition method and reported for the first time. As a result, P, Co-CuNi only requires an ultralow overpotential of 56mV to drive the current density of 10mA cm-2, with remarkable stability for over 360h, surpassing most previously reported transition metal-based materials. It is discovered that the P doping can simultaneously increase the electrical conductivity and enhance the corrosion resistance, while the introduction of Co can precisely modulate the sub-nanosheets morphology to expose more accessible active sites. Moreover, XPS, UPS, and DFT calculations reveal that the synergistic effect of different dopants can achieve the most optimal electronic structure around Cu and Ni, causing a down-shifted d-band center, which reduces the hydrogen desorption free energy of the rate-determining step (H2O + e- + H* → H2 + OH-) and consequently enhances the intrinsic activity. This work provides a new cognition toward the development of excellent activity and stability HER electrocatalysts and spurs future study for other NiCu-based alloy materials.

ВЛИЯНИЕ РЕЖИМОВ ЛАЗЕРНОЙ ОБРАБОТКИ БИМЕТАЛЛА ВТ1-0+МН19 НА СТРУКТУРУ И МИКРОМЕХАНИЧЕСКИЕ СВОЙСТВА ВАННЫ ПЕРЕПЛАВА

It has been established that during laser processing of a bimetal copper-nickel alloy MN19 + titanium VT1-0 mode with a power P = 1400 W and a laser beam speed of 0.8 m/min with a diameter of 2 mm provides optimal characteristics of the remelting bath in terms of hardness and uniformity of structure. It has been shown that a remelting bath with a homogeneous structure is ensured at a specific radiation energy of 52.52 J/mm2. In this case, an increase in the microhardness of the remelting bath by 1 GPa with an increase in the speed of movement of the laser beam and a decrease in the diameter of the spot is explained by an increase in its cooling rate.

Accelerated corrosion of 70/30 copper-nickel alloys in sulfide-polluted seawater environment by sulfide

The effect of sulfides on the pitting corrosion behavior and film chemistry of 70/30 copper-nickel alloys in aerated seawater was investigated. Sulfides in seawater prevent the formation of protective oxides on the surface of the alloy and alter the morphology and composition of the corrosion products. It results in the corrosion product film consisting of the double layer structure of the loose and porous sulfide-containing outer layer and the dense inner layer. This double-layer structure of the corrosion product film can't alleviate corrosion, but instead accelerates the development of pitting corrosion. The statistical analysis method is used to study the corrosion process of 70/30 copper-nickel alloy in sulfide-containing environment. This work records the trend of pitting corrosion towards the horizontal and longitudinal directions.

Indentation-induced plastic behavior of nanotwinned CuNi alloy: an atomic simulation

This study uses molecular dynamics simulations to explore the mechanical properties of a nano-twinned copper–nickel alloy during indentation. We investigate the impact of twin boundary (TB) angles and spacing on the alloy’s behavior. The plastic deformation process is primarily driven by dislocation generations, slips, and TB interactions, directly affecting the alloy’s hardness. Significant findings include: (1) hardness initially decreases, then increases with increasing TB angle θ, and for TB spacing d greater than 1.25 nm, hardness can be predicted using a simple proposed model; (2) dislocation density ρ experiences significant variations, leveling off at an indentation depth around 1.0 nm; (3) when TB spacing d exceeds 1.25 nm, plastic deformation is dominated by dislocation nucleation, slips, and boundary interactions, while smaller spacings lead to TB migration and the presence of independent dislocation loops, giving rise to force fluctuations along indentation.

Study on mechanism underlying the acceleration of pitting corrosion of B30 copper–nickel alloy by sulfate-reducing bacteria in seawater

In this paper, the relationship between the pitting corrosion formation of B30 copper–nickel (CuNi) alloy and the metabolism of sulfate-reducing bacteria (SRB) was investigated. Combined with the influence of temperature during the actual operation of the cooling systems, the evolution law of the alloy passivation film was analyzed, and the mechanism of SRB promoting the accelerated development of B30 CuNi alloy pitting corrosion was revealed. The results show that SRB significantly promoted the pitting formation and development of B30 CuNi alloy. The maximum pitting depth was 3.9 μm in the sterile system and 15.3 μm with SRB, which was 3.9 times higher than that of sterile system. The loose porous Cu2S film formed by SRB metabolites and copper matrix was easily penetrated by corrosive anions, which promoted copper dissolution and led to pit nucleation. The sulfide adsorbed on the surface prevented or delayed the passivation of B30 CuNi alloy by blocking the adsorption site of O atom, and the corrosion nuclei continued to grow. The non-uniformity caused by the film peeling accelerated the longitudinal development of pitting corrosion, and the expansion and coalescence of adjacent pits caused the transverse development of pitting corrosion. Temperature had a certain influence on the SRB and the formation of B30 CuNi alloy passivation film. The passivation film was formed rapidly at 50 °C with poor quality and the passivation property of Cu2O film was weakened. With the increase of temperature, the pitting potential of sterile system negative shifted from 0.447 to 0.360 V (vs. SCE), while SRB system from 0.340 to 0.198 V (vs. SCE), and the pitting resistance decreased. The passivation film with defects and the Cu2S reduced the barrier efficiency of the film and accelerated the pitting corrosion of B30 CuNi alloy.

Investigation on mechanical properties and corrosion behavior of laser powder bed fusion 70/30 copper-nickel alloy

70/30 copper-nickel alloy was manufactured by laser powder bed fusion (LPBF), followed by the comprehensive investigation on the relationship between its microstructures and mechanical properties as well as corrosion behavior. The results show that dislocation tangles at cellular boundaries can greatly contribute to its superior tensile properties than the commercial counterpart. In addition, the combination of dislocation tangles and nanoscale copper enrichment/nickel depletion directly leads to the heterogeneous film formation process during immersion in corrosive media. Moreover, experimental and computational results both suggest that exposed facets are another important role to determine the corrosion behavior of LPBF 70/30 copper-nickel alloy.

Copper–Nickel Alloy Friction Surfaced Coating on Steel Substrates for Marine Applications

Copper–Nickel Alloy Friction Surfaced Coating on Steel Substrates for Marine Applications

Influence of Cobalt content on the microstructure and texture evolution of hot-press sintered Tungsten nickel copper Alloy (W-Ni-Cu)

This study examines the effect of cobalt on the crystallographic texture and grain boundary evolution of hot-press sintered tungsten heavy alloy (W-4.9Ni-2.1Cu). Traditional tungsten heavy alloy with a Ni:Cu ratio of 7:3 has cobalt added (i.e., cobalt content increased from 0 to 1 wt% with a 0.25 wt% interval). The samples were produced using the hot press sintering method with the following parameters: 50 MPa pressure, 10 °C/min heating rate, 1450 °C temperature, and a 20-min hold time. The unalloyed cobalt WHA compact has a fibre texture in the (001) plane that is aligned in the 〈111〉 orientation. In addition, the cobalt-alloyed WHAs compacts exhibit a lower proportion of grain boundaries with low angles. Enhanced solid solution formation between cobalt and WHAs during liquid phase sintering led to increased compacts densification and randomised weak fibre development in cobalt-alloyed compacts. Texture deterioration (001) <111> in cobalt-added WHAs is caused predominantly by substructural recovery during liquid phase sintering. This study indicates that the addition of cobalt to the stoichiometry of WHAs resulted in the homogenous distribution of binder matrix within the compact during sintering. As a result, the W-4.9Ni-2.1Cu-1Co alloy exhibited improved microhardness (429.5 HV0.5), electrical conductivity (23.34% of IACS), and relative density (98.10%).

Influence of Nickel Content on the Formation of an Interaction Zone during Contact Melting of Titanium with Copper-Nickel Alloys

The diffusion processes during the contact melting at the boundary of explosively welded VT1-0 titanium with CuNi19 (melchior) and CuNi45 (constantan) alloy composites were studied. Heat treatment of composites led to the formation of the interaction zone at the joint boundary. The interaction zone in VT1-0 + CuNi19 consists of TiCuNi and αTi + Ti2Cu(Ni) continuous layers as well as a mixture of TiNi(Cu) + TiCu(Ni) + Ti2Cu(Ni) intermetallics. It has been shown that an increase in the nickel content in the case of VT1-0 + CuNi45 composite leads to a decrease in the temperature of contact melting, a change in its mechanism, an increase in the titanium content in the interaction zone, and the appearance of additional Ti2Ni(Cu) intermetallic in its composition.