Properties Of Cu Research Articles

Effect of particle size on microstructure and properties of Cu–Cr2O3 composites prepared by supercritical water in situ oxidation

Effect of particle size on microstructure and properties of Cu–Cr2O3 composites prepared by supercritical water in situ oxidation

Characterisation of the interplay between microstructure and opto-electronic properties of Cu(In,Ga)S2 solar cells by using correlative CL-EBSD measurements

Cathodoluminescence and electron backscatter diffraction have been applied to exactly the same grain boundaries (GBs) in a Cu(In,Ga)S2 solar absorber in order to investigate the influence of microstructure on the radiative recombination behaviour at the GBs. Two different types of GB with different microstructure were analysed in detail: random high angle grain boundaries (RHAGBs) and Σ3 GBs. We found that the radiative recombination at all RHAGBs was inhibited to some extent, whereas at Σ3 GBs three different observations were made: unchanged, hindered, or promoted radiative recombination. These distinct behaviours may be linked to atomic-scale grain boundary structural differences. The majority of GBs also exhibited a small spectral shift of about ±10 meV relative to the local grain interior (GI) and a few of them showed spectral shifts of up to ±40 meV. Red and blue shifts were observed with roughly equal frequency.

Impact of substituents on luminescence and mechanochromism of two novel monometallic copper(I) complexes

Two new mononuclear Cu(I) complexes, [Cu(cbpy)(BINAP)]ClO4 (1) and [Cu(mcbpy)(BINAP)]ClO4 (2), have been synthesized and characterized (cbpy = 6-cyano-2,2ʹ-bipyridine, mcbpy = 4,4ʹ-dimethyl-6-cyano-2,2ʹ-bipyridine, BINAP = 2,2ʹ-bis(diphenylphosphino)-1,1ʹ-binaphthyl). Both Cu(I) complexes are photo-luminescent in the solid state at ambient temperature, with similar emission bands at 620 and 601 nm, respectively. Complex 2 exhibits the mechanochromic luminescence behavior with emission color changing from orange to orange-red, which is mainly due to the breakage of multiple CH⋯O hydrogen bonds between mcbpy-CH and counter-ion ClO4− under grinding. In contrast, the mechanochromic luminescence is not observed in 1 with much weaker cbpy-CH⋯O hydrogen bonds than those of 2. These clearly suggest that the methylation of 2,2ʹ-bipyridyl has an important effect on the mechanochromic luminescence properties of Cu(I) complexes. In addition, the potential applications of 2 have been investigated.

High strength and excellent softening resistance Cu–15Ni–8Sn alloy by Ti addition

Cu–15Ni–8Sn alloy is commonly utilized in various applications because of its exceptional strength, elasticity, and softening resistance. Ti microalloying has been employed to enhance the mechanical properties of Cu–15Ni–8Sn alloy. By adding 0.5 wt% Ti, the peak-ageing tensile strength, microhardness, and elastic modulus of the Cu–15Ni–8Sn alloys reach 1401.3 MPa, 479.3 Hv, and 154.7 GPa, respectively, representing the greatest comprehensive performance reported in previous literature. Additionally, the Ti microalloying significantly enhances the softening resistance of Cu–15Ni–8Sn alloys. After ageing at 400 °C for 10 h, the tensile strength of the Cu–15Ni–8Sn-0.5Ti alloy decreases by only around 150 MPa, whereas the alloy without Ti addition experiences a decrease close to 350 MPa. Quantitative analysis reveals that the observed improvements can be attributed to the Ti microalloying inhibiting the dislocation annihilation and the formation of discontinuous precipitation during the ageing process, while simultaneously promoting the precipitation of Ni3Ti. This study provides a theoretical basis for preparing a high-performance Cu–15Ni–8Sn alloy by microalloying.

Achieving high strength and high elasticity of Cu–Ni–Cr–Mn alloy by synergistic effect of multi-scale precipitates

The microstructural evolution, precipitation behavior and mechanical properties of Cu–19Ni–6Cr-xMn (x=0, 1, 3, 5, 7, 9 wt%) alloys were examined in the presence of solution treatment, cold rolled treatment and aged treatment. The results show that aged Cu–19Ni–6Cr–7Mn alloy exhibits superior mechanical properties with a hardness of 379 HV, tensile strength of 1012 MPa, and elastic modulus of 149.5 GPa, which is the maximum reported value for elastic modulus of copper alloys. The Mn element promotes the uniform distribution of the precipitates and grain refinement. Thermodynamic calculations indicate that the formation of the NiMn precipitates takes precedence over the NiCr-rich precipitates in this alloy. Three typical precipitates were detected in the Cu–19Ni–6Cr–7Mn alloy, including submicron-sized Cr-rich precipitates (>500 nm), nano-sized bcc-Cr precipitates (30–70 nm), and nano-sized NiMn precipitates with L12 ordered structure (3–5 nm). Precipitation plays a major role in improving the strength of the alloy. The synergistic effect between multi-scale precipitates, high-density dislocations, and solution strengthening has achieved significant breakthroughs in mechanical properties which open up new possibilities for engineering applications requiring high-strength and high-elasticity copper alloys.

Effects of three different powder pre-processing and two-step sintering processes on the microstructure and mechanical properties of Cu–Sn–Ti porous matrix materials

It is difficulty to utilize the pore formation function of TiH2 in the copper-based matrices of diamond tools due to the mismatch between dehydrogenation temperature and densification temperature. In this study, Cu–Sn–Ti porous materials were prepared by innovative powder pre-processing and two-step sintering processes. The results showed that Cu–Sn–TiH2 powder with uniform composition, high alloying degree and high TiH2 retention rate were achieved by optimizing pre-processing parameters. During the subsequent sintering process, Sn and Ti elements were precipitated from the copper matrix, leading to the formation of Ti-rich phases at grain boundaries and pore walls. Simultaneously, pores with higher sphericity and uniform distribution were formed due to the thermal decomposition of TiH2. The porosity, average pore size, bending strength, and bending elastic modulus of Cu–Sn–Ti porous material were measured as 30.6%, 2.15 μm, 245 MPa, and 2.23 GPa, respectively. The comprehensive properties were better than the reported results.

Photocatalytic Degradation of Crystal Violet on Cu, Zn Doped BiVO4 Particles.

Fabrication of codoped photocatalysts is a developing area of research. Herein, we explore the visible light photocatalytic properties of Cu, Zn codoped BiVO4 particles. Doping lower valent cations (Cu and Zn) makes the BiVO4 surface more acidic and enables us to target the basic crystal violet (CV) dye. The adopted hydrothermal protocol of synthesis results in the formation of Cu-Zn codoped monoclinic BiVO4 particles. Undoped monoclinic BiVO4, prepared by the same protocol, showed significant formation of oxygen vacancies. XPS analyses confirm the coexistence of Cu2+/Cu+ and Zn2+ dopants. Increased dopant percentage reduced oxygen vacancies. XRD indicates that Cu2+/Cu+ or Zn2+ dopants generally substitute Bi3+ in BiVO4. All photocatalysis activities for CV degradation are reported under near-neutral pH conditions. A typical codoped BiVO4 photocatalyst with 1% Zn and 2% Cu demonstrated the best CV degradation photocatalytic activity. The activity of this Zn, Cu codoped photocatalyst is better than that of pure, Zn-doped, and Cu-doped BiVO4 samples. Active species trapping experiments indicated the possible photocatalysis mechanism. The photocatalysts exhibited appropriate recyclability and photostability.

A novel approach to predict the effect of chemical composition and thermo-mechanical processing parameters on Cu–Ni–Si alloys using a hybrid deep learning and ensemble learning model

The study presents a novel hybrid deep learning and ensemble learning (DL-EL) model to predict the effects of chemical composition and thermo-mechanical processing on the properties of Cu–Ni–Si alloys. The model integrates various input parameters like chemical composition and thermo-mechanical processing parameters and aims to predict key output properties such as mechanical properties and electrical conductivity. This study addresses gaps in existing research by providing a comprehensive model for Cu–Ni–Si alloys and integrating thermo-mechanical processing parameters with chemical composition in the predictive model. The research demonstrates the model's superior predictive performance, with near-perfect R2 values on both training and test sets. The hybrid DL-EL model was compared with three other machine learning models and its efficacy was assessed using R2 value, offering new insights into the performance of these alloys. A feature importance analysis was conducted to identify the most influential features of the model. This work contributes to the material science field by providing insights into optimizing alloy composition and processing, leveraging machine learning to enhance material design.© 2017 Elsevier Inc. All rights reserved.

Gamma irradiated Cu-doped TiO2 nanoparticles for selective ammonia sensing

In this research, the effect of gamma ray doses on volatile organic compound (VOC) sensing properties of Cu doped TiO2 nanoparticles are studied to further improve the VOC sensing performance. Pure and Cu doped TiO2 nanoparticles have been prepared by sol-gel technique on Au interdigitated plexiglas substrate and irradiated by gamma-rays with doses varying from 1 to 150 KGy. The irradiation was performed by using 60Co as gamma source. The structural, morphology and modifications were analyzed with X-ray diffraction (XRD), scanning electron microscopy (SEM), and Atomic Force Microscopy (AFM) techniques. The sensing performance of these films toward ethanol, methanol, 2-propanol, benzene, toluene, xylene and ammonia vapors has been tested. It was observed that no remarkable sensor response to any vapors except ammonia was observed at room temperature. Changes in sensor’ ammonia sensitivity have been correlated with the gamma radiation dose and Cu doping ratio. Maximum sensing performance was observed with 3% Cu doped TiO2 exposed to gamma radiation dose of 150 kGy.

Effect of short heat treatment on mechanical properties and shape memory properties of Cu–Al–Ni shape memory alloy

Abstract The transformation of shape-memory alloys to high-temperature shape-memory alloys can be achieved through either the addition of alloying elements or heat treatment. However, heat treatment is more effective in improving the properties of the alloys. This research paper explores the impact of annealing on the mechanical and shape memory properties of Cu–Al–Ni shape memory alloys. The alloys were first cast, homogenized, and then machined before being aged at temperatures of 250, 300, and 350°C, and finally air-cooled. The results showed an increase in transformation temperature and recovery strain, as well as shape memory effect, and a decrease in hardness. Moreover, there was an increase in yield stress and strain. In conclusion, aging was found to improve the shape memory properties and mechanical properties better than thermomechanical treatment and some alloying elements.

"Investigation of Structural, Electrical, Magnetic, and Optical Properties of Cu (111) and the Impact of Ag Adatoms Adsorption: A Density Functional Theory Study"

Our study conducts a comprehensive investigation on the structural, electrical, magnetic and optical properties of pure Cu with a (111) crystallographic orientation, as well as the impact of the adsorption of Ag adatoms on a Cu (111) surface. To perform this analysis, we utilized the full potential linearized augmented plane-wave (FP-LAPW) approach in conjunction with Generalized Gradient Approximations (GGA + U) and the Wien2k simulation software. Specifically, we calculated electrical and optical properties including the band structure, density of states (DOS) for the Cu (111) surface with and without the presence of adsorbed Ag atoms. Based on the observed results, the overlapping of the electronic bands for simple Cu (111) is comparatively less than that of adsorbed Ag/Cu (111) slab, indicating higher conductivity. Moreover, the evolutions are also observed which are mainly due to d orbitals of Cu and Ag for Cu (111) and Cu/Ag (111) respectively. The calculated magnetic optimization and weak diamagnetic magnetic moments shows weak diamagnetism in these materials. The optical properties like Dielectric Function(ε), Refractive index(n), Extinction co-efficient(k), Reflectivity(R), Energy Loss (L), Absorption (α) and Optical conduction (σ) are calculated. Our research examines the importance of band structure calculation in relation to optical properties. We discuss how plasmon-energy plays a crucial role in producing peaks in the energy loss function, with a crystallographic axis of 13.7eV and 13.6eV for both Cu (111) and Ag/Cu (111) slab. In addition, we calculated the static dielectric function, absorption coefficient, and refraction values for these materials. Reflectivity spectra for both Cu (111) and Ag/Cu (111) exhibits Infra-red region, indicating good coating materials to reduce heating, for the application of electrical appliances and for optical application like anti-reflecting coating, optical fibers and solar cells.

Spectroscopic insights into the influence of oxidation on the binding properties of Cu(II) onto biochar-derived dissolved organic matter

The oxidation may change the composition, content, and structure of biochar-derived dissolved organic matter (BDOM) that influences the geochemical behavior of heavy metals (HMs) when biochar is applied. Herein, the binding characteristics of Cu(II) onto BDOM and oxidized BDOM (OBDOM) were investigated using synchronous fluorescence spectra (SFS) and Fourier transform infrared (FTIR) spectroscopy in combination with two-dimensional correlation spectroscopy (2D-COS). The results showed that the content of BDOM300 and BDOM600 decreased by 30.21% and 13.67% respectively after oxidation. Humic-like substances are dominated in the BDOM, which can be preferentially oxidized. Meanwhile, humic-like substances (e.g. 412 nm in the BDOM300, 490 nm in the OBDOM300, 525 nm in the BDOM600, and OBDOM600) can preferentially react with Cu(II). The functional groups, at 1712 cm−1 in the BDOM300, 1631 and 1290 cm−1 in the OBDOM300, 1515 cm−1 in the BDOM600, 1740 cm−1 in the OBDOM600, played important roles in the complexation between humic-like substances and Cu(II). The logarithmic conditional stability constant (Log K) of the complexes is higher in the OBDOM300 than those in the BDOM300, and higher in the OBDOM600 than those in the BDOM600. The results also indicated that the presence of BDOM promoted the adsorption of Cu(II) by BC300 and BC600, and inhibited the adsorption of Cu(II) by OBC300 and OBC600. Therefore, it is particularly important to insight into the effect of oxidation on the binding properties of Cu(II) and BDOM. This study can provide scientific guidance for the use of biochar in the remediation of HMs.

Facile fabrication of layer-structured graphene/copper composite with enhanced electrical and mechanical properties

Copper (Cu) and its related composites are widely used and hence extremely important in industrial applications. Much efforts have been made to improve the physical properties of Cu, but usually lead to degradation of electrical performance. Herein, this work develops a facile way to fabricate layer-structured graphene/copper composite using graphene powder sprayed on Cu foil as building blocks. Compared to pure Cu bulk, significant improvement of both the electrical conductivity of 105.12% IACS and also ∼17% enhanced tensile strength is achieved. This strategy provides a versatile way to produce high-performance Cu composite in large with low cost for practical applications.

Highly efficient enhancement of mechanical and tribological properties of Cu-based composites by addition of graphene-loaded Ni metal particles

The tight interface between graphene and Cu is the key to give full play to the comprehensive properties of Cu / C composites. In this study, graphene was used as a Cu-based reinforcing phase, and the interfacial bonding strength between graphene and Cu was enhanced by introducing Ni metal nanoparticles. Graphene supported Ni nanosheets (Ni-RGO) were successfully prepared by in-situ chemical reduction of graphene oxide (GO) and the introduction of Ni nanoparticles into GO. Ni nanoparticles were tightly attached to the graphene sheets. The mechanical properties and tribological properties of Ni-RGO/Cu composites were significantly improved. The bending strength of Ni-RGO/Cu composites reached 162.2 MPa, which was much higher than that of the pure Cu. At the same time, Ni-RGO composites have the lowest wear rate, and the friction coefficient is stable between 0.1 and 0.2. The comprehensive performance of Ni-RGO composites is significantly enhanced due to the unique structure of Ni-RGO, and the introduction of Ni nanoparticles realizes the effective bonding between GO-Ni-Cu. This study provides a new and effective strategy for enhancing the interfacial bonding of Cu/C composites.

Sensitivity and Selectivity Detection Studies of Fe (III) Using Cu(I) Complex of Schiff Base Material

The liver, bones, kidneys, teeth, and central nervous system sustain serious damage as a result of heavy metal ions entering the human food chain. In order to improve public health, new techniques must be developed for the rapid, easy, simple, reliable, low-cost, and reliable identification of toxic metal ions.Naked eye detection of hazardous metal ions with Cu (I) fluorescent properties of Cu(I) Complex of with 2, 2′-bipyridine and trans cinnamic acid were investigated. The structure of the fluorescent Cu (I) complex was characterized by conductivity measurement, elemental analysis, UV-Visible and FT-IR. The Cu (I) complex was soluble in dimethylsulfoxide, distilled water, methanol and insoluble in tetrahydrofuran. In the applications, firstly the color of the Cu(I) complex was compared with/without metal ions, and then the measurements were made in the UV-Vis spectrophotometer to exhibit selective and sensitive to Fe3+ ions in DMSO (dimethylsulfoxide) / H2O (water) (v/v, 1:1). Cu(I) complex exhibited absorbance band at 323 nm in dimethylsulfoxide. The absorbance intensity was decreased by Fe (III) and behaves as a turn-off sensor. The sensor showed high selectively and sensitivity toward Fe (III) over the other cations in dimethlsulfoxide solution. The equilibrium binding constant of Cu (I) complex with Fe (III) was 1.9x10 4 M -1 as calculated using stern –volmer equation. The limit of detection was also determined and calculated as 0.219 μM. Based on facts obtained from this study, the author suggests the Copper (I) complex response to Fe (III) rapidly and a large number of consecutive ions showed almost no obvious absorbance change during detection. Copper (I) complex could act as cost effective, selective, specific and sensor for detection of Fe (III) ions over other metal ions.

Effect of pulse time (Ton), pause time (Toff), peak current (Ip) on MRR and surface roughness of Cu–Al–Mn ternary shape memory alloy using wire EDM

Shape memory and super elasticity are two outstanding properties of Cu–Al–Mn SMAs together with additional copper-based shape memory alloys that make them superior to NiTi alloys. It's quite hard to machine Cu–Al–Mn SMA. The machinability properties of Cu–Al–Mn SMAs during Wire Electrical Discharge Machining (WEDM) were experimentally investigated using molybdenum wire as the electrode material. Material Removal Rate (MRR) and Surface Roughness (SR) are two machining qualities that are studied in relation to the combinational values of pulse time (Ton), pause time (Toff), and peak current (Ip), which are selected as the changeable input process factors. From the experimental investigation, it was found that both MRR and Ra values were increased with an increase in pulse on time(Ton), pulse off time(Toff), and peak current (IP)values. Because the wire electrode contains maximum current under these conditions, it is easy to remove more material at the tool and work material interface, resulting in moderate surface finish. Surface quality was higher on samples machined at low energy input than it was on samples machined at high energy input. This SEM micrograph clearly shows that a lower pulse on time produces a superior surface quality.SEM images and the analysis of the machined surface morphology on the surface of the CAM7 alloy clearly showed that the machined surface of the alloy had a lower surface roughness value at a lower Ip-2A and was associated with a higher surface roughness value at a higher Ip-6A, as well as a lot of uncleared debris and blow holes.

Effect of Copper Particle Size on the Surface Structure and Catalytic Activity of Cu–CeO2 Nanocomposites Prepared by Mechanochemical Synthesis in the Preferential CO Oxidation in a H2-Rich Stream (CO-PROX)

An effect of Cu powder dispersion and morphology on the surface structure and the physical–chemical and catalytic properties of Cu–CeO2 catalysts prepared by mechanochemical synthesis was studied in the preferential CO oxidation in a H2-rich stream (CO-PROX). Two catalysts, produced by 30 min ball-milling from CeO2 and 8 mass% of copper powders and with particle sizes of several tens (dendrite-like Cu) and 50–200 nm (spherical Cu obtained with levitation-jet method), respectively, were characterized by X-ray diffraction and electron microscopy methods, a temperature-programmed reduction with CO and H2, and with Fourier-transform infrared spectroscopy. The catalyst synthesized from the “large-scale” dendrite-like Cu powder, whose surface consisted of CuxO (Cu+) agglomerates located directly on the surface of facetted CeO2 crystals with a CeO2(111) and CeO2(100) crystal planes exposition, was approximately two times less active at 120–160 °C than the catalyst synthesized from the fine Cu powder, whose surface consisted of CuxO (Cu2+) clusters of 4–6 nm in size located on the steps of facetted CeO2 nanocrystals. Although a large part of CO2 reacted with a ceria surface to give carbonate-like species, no blockage of CO-activating centers was observed due to the surface architecture. The surface structure formed by the use of highly dispersed Cu powder is found to be a key factor responsible for the catalytic activity.

EFFECT OF RANDOM DISTRIBUTION AND SHORT-RANGE ORDERING OF SOLUTES ON THE MECHANICAL PROPERTIES OF NANOCRYSTALLINE Cu–Ag ALLOYS

The effects of solute random distribution (RSS) before relaxation and solute short-range ordering (SRO) after relaxation on the mechanical behavior of nanocrystalline Cu–Ag alloys were analyzed by molecular dynamics simulation. It has been found that the mechanical properties of Cu–Ag alloy mechanics with SRO were better than those of Cu–Ag alloy mechanics with RSS. Specifically, during the whole tensile process, compared with sample #1 with SRO structure, sample #2 with RSS structure has stronger strain–stress response ability, more obvious phase transformation process, and narrower shear strain zone on the grain boundary. Furthermore, when the number of Voronoi seeds is examined concerning the mechanical properties of the nanocrystalline Cu–Ag alloy, it becomes apparent that the average flow stress drops as the quantity of Voronoi seeds increases.

The composition effect on the structural and thermodynamic properties of Cu–Ag–Au ternary nanoalloys: a study via molecular dynamics approach

Metal ternary nanoalloys or trimetallic nanoparticles have emerged, in recent years, as novel and relevant materials in different fields due to the synergy of three metals in a single system that leads to unique physicochemical properties as compared to mono- and bimetallic nanoparticles. In this study, the influence of composition on the structural and thermodynamic properties of Cu–Ag–Au nanoalloys with 5083 atoms is analyzed using molecular dynamics simulations. Relevant thermodynamic quantities are used to describe the melting and solidification behaviors of three models of Cu–Ag–Au nanoalloys. Our results indicate that the melting temperature presents linear and quadratic dependencies with the composition, i.e. for Cu33Ag 67−x Au x , Ag33Cu 67−x Au x , and Au33Ag 67−x Cu x are Tm=912.6+1.9x , Tm=882.3+2.7x , and Tm=1056.6−4.9x+0.07x2 , respectively. In addition, most Ag atoms segregate to the surface and the Au and Cu atoms are localized in the center of the nanoalloy during the heating process, and this trend is maintained in the cooling process. The solidification temperature does not have an explicit correlation with the composition. Furthermore, the structural analysis of cooled nanoalloys exhibits local FCC and HCP symmetries, and the excess energy shows that Cu33Ag27Au40, Au33Ag17Cu50, and Ag33Cu37Au30 are relatively more stable to form nanoalloys. Finally, the possibility of controlling the composition in these metal nanoalloys opens up potential applications in plasmonic, catalysis, and bactericidal (by Ag surface segregation) fields.

Optimizing mechanical and electrical properties of Cu–3Zr alloy by thermomechanical processing

Cu–3Zr alloy was prepared by powder metallurgy and two-stage thermomechanical process, and the microstructure evolution and properties were investigated. The results show that the microstructure of as-sintered Cu–3Zr alloy is consisted of the coarse Cu–Zr intermetallic compounds and equiaxed Cu grains. After extrusion, the second phase is smaller in cross section, while deformation texture of the Cu matrix can be seen from longitudinal section. After further drawing, the Cu grains are elongated and the Cu–Zr intermetallic phase is broken into fine particles. The yield strength (YS), ultimate tensile strength (UTS) and electrical conductivity are 593 MPa, 684 MPa, and 74%IACS, which are respectively increased by 38%, 34% and 21% as compared to the as-sintered Cu–3Zr alloy. Phase analysis and microstructural characterization demonstrate that the Cu5Zr, Cu8Zr3, and Cu10Zr7 precipitates are uniformly distributed in the Cu matrix. Cu5Zr/Cu and Cu8Zr3/Cu are combined in the form of coherent relation. Cu10Zr7/Cu are combined in the form of semi-coherent relation. The enhanced mechanical properties can be attributed to the multiple synergistical strengthening effect. The elongated Cu grains and fine Cu–Zr precipitation phases block the movement of dislocation, resulting in the remarkable enhancement of strength. Moreover, the elongated Cu grains can provide fast channel for the electron transport, giving rise to simultaneous increase of the electrical conductivity.