Properties Of Cu Research Articles

Composition-Tunable Properties of Cu(Ag) Alloy for Hybrid Bonding Applications

In the present study, the properties of Cu(Ag) alloy films were studied to evaluate their potential use as an alternate material for interconnection in hybrid bonding. Thin alloy films of Cu(Ag) were deposited by pulsed electrochemical deposition (PED) using a sulfuric acid-based bath, rotating disk electrode, and hot entry. Secondary ion mass spectrometry (SIMS) was used to measure the silver content of the films, with us finding that it decreases with increasing duty cycle. Thereafter, bright field scanning transmission electron microscope (STEM) imaging in combination with energy-dispersive x-ray spectroscopy (EDS) was used to visualize the thin film microstructure and to confirm the uniform distribution of silver throughout the film, with no bands being seen despite the pulsed nature of the deposition. Film resistance was measured by a four-point probe to quantify the impact of Ag content on resistivity, with us finding the expected linear relationship with the Ag content in the film. Furthermore, the coefficient of thermal expansion (CTE) of the films was measured using X-ray diffraction, and modulus and hardness were measured via nanoindentation, revealing linear dependences on the Ag content as well. Notably, the addition of 1.25 atom% Ag resulted in a significant increase in the CTE from 17.9 to 19.3 ppm/K, Young’s modulus from 111 to 161 GPa, and film hardness from 1.70 to 3.99 GPa. These simple relationships offer a range of properties tunable via the duty cycle of the pulsed plating, making Cu(Ag) a promising candidate for engineering wafer-to-wafer metal interconnections.

Rhododendron simsii leaf extract as a corrosion inhibitor for Cu in 0.5 M H2SO4: Experimental and theoretical studies

This study focuses on the utilization of a facile method to obtain Rhododendron simsii leaves extract (RSLE) as an efficient green corrosion inhibitor for Cu in 0.5 M H2SO4. The functional groups in RSLE were characterized using Fourier transform infrared spectroscopy (FTIR). The corrosion inhibition effect of RSLE was comprehensively evaluated by combining weight loss, electrochemical and surface analysis methods. The results showed that the maximum corrosion inhibition efficiency for Cu in the temperature range of 298 K∼308 K was more than 92.6% when the concentration of RSLE was 500 mg/L. RSLE is a mix-type corrosion inhibitor, and the adsorption on the surface of Cu was in accordance with the Langmuir model. In addition, the reaction sites and adsorption configurations on the Cu (1 1 1) surface of several typical active molecules in RSLE were analyzed by quantum chemistry (QC) and molecular dynamics simulation (MDS). The combination of experimental and theoretical results confirms that RSLE has excellent corrosion inhibition properties for Cu in acidic environments. In this study, an efficient corrosion inhibitor for copper corrosion in acidic environments was extracted for the first time from Rhododendron simsii leaves, providing a new perspective for future Cu corrosion prevention studies.

Microstructure and properties of Cu–Ni–Co–Si–Cr–Mg alloy by multistage thermomechanical treatment

A Cu–1.3Ni–1.2Co–0.7Si–0.3Cr–0.1Mg alloy with high strength and medium conductivity was designed and prepared. The effects of multistage thermomechanical treatment on the microstructure and properties of the alloy and its strengthening mechanism were studied. The results showed that a large number of nanoscale β-Ni3Si, δ-(Ni,Co)2Si and Cr phase particles precipitated in the high-density dislocation region and sub-grain boundaries during aging, and submicron Cr3Si phase particles formed during solidification of the alloy. The tensile strength, yield strength and electrical conductivity of the alloy were 882 MPa, 857 MPa and 46.7% (IACS), respectively. The main strengthening mechanisms of the alloy were precipitation strengthening, strain strengthening and sub-structure strengthening through the strengthening model calculation and measured strength.

Structural and optical properties of Cu implanted Ge thin films

Effects of rapid thermal annealing (RTA) on 100 keV Cu implanted germanium (Ge) thin films were studied in the present report. The Cu ion implantation into Ge films was carried out at different ion fluences 5 × 1015 and 1 × 1016 ions/cm2. Subsequently, the implanted samples were subjected to RTA at 600 °C. XRD and Raman results illustrate the amorphization of implanted films, whereas RTA results in crystallization. Crystallite size increases from 10.5 to 11.6 nm with fluence for RTA-treated samples. The bandgap of pristine film is 0.73 eV, which gets narrowed to 0.59 eV with an increase in ion fluence. RTA leads to increase in band gap up to 1.16 eV due to recovery of lattice damage and recrystallization of films. XPS analysis of RTA-treated implanted films reveals the presence of Ge, Ge suboxides, and Cu. The broad PL emission in the visible region signifies the possible use of Ge for optoelectronic applications.

The structural effect of SiC form ceramic on the compressive strength and thermal expansion properties of Cu–SiC composites

With the development of transportation vehicles towards to the direction of heavy load and high speed, the requirement of Cu matrix brake materials was proposed for improving performance in both mechanical and thermal properties. The Cu-SiCf composites is a new kind of friction brake material. To investigate the structural effect of 3D network structured SiC form ceramic on the compressive strength and thermal expansion properties of Cu-SiCf composites, SiCf was synthesized using a template method in conjunction with reaction sintering, while Cu-SiCf composites were prepared using squeeze casting, and exhibiting a co-continuous phase structure. The results reveal that SiC form ceramic reinforcement and constraint mechanisms enhance the overall strength of the Cu alloy through the 3D network structure. SiC form ceramic plays a role in load transfer and overall strengthening of the Cu alloy. With the synergistic effects of these mechanisms, increasing the SiC form ceramic volume fraction improves the compressive strength and reduces the coefficient of thermal expansion of the Cu-SiCf composites.

Processing and Properties of ZrB2-Copper Matrix Composites Produced by Ball Milling and Spark Plasma Sintering

Copper matrix composites with zirconium diboride (ZrB2) were synthesised by ball milling and consolidated by Spark Plasma Sintering (SPS). Characterisations of the ball-milled composite powders were performed by scanning electron microscopy (SEM), X-ray diffraction, and measurement of the particle size distribution. The effect of the sintering temperature (1123 K, 1173 K, and 1223 K) and pressure (20 MPa and 35 MPa) on the density, porosity, and Young’s modulus was investigated. The relationship between the change of Orb content and physical, mechanical, and electrical properties was studied. Experimental data showed that the properties of Cu–Orb composites depended significantly on the SPS sintering conditions. The optimal sintering temperature was 1223 K with a pressure of 35 MPa. Composites exhibited a high degree of consolidation. For these materials, the apparent density was in the range of 93–97%. The results showed that the higher content of Orb in the copper matrix was responsible for the improvement in Young’s modulus and hardness with the reduction of the conductivity of sintered composites. The results showed that Young’s modulus and the hardness of the Cu 20% Orb composites were the highest, and were 165 GPa and 174 HV0.3, respectively. These composites had the lowest relative electrical conductivity of 17%.

Study on the regulation of microstructure and mechanical properties of Cu–15Sn-0.3Ti alloy by a novel mechanical-heat-electricity synergistic method

The matching of mechanical properties between Cu–15Sn-0.3Ti alloy and Nb was the key to the formation of Nb3Sn superconducting wires. However, the Cu–15Sn-0.3Ti alloy treated with homogenized annealed (HA) still could not meet the requirements for synergistic deformation with Nb. In this work, a novel mechanical-heat-electricity synergistic method was proposed, which successfully formed equiaxed crystal microstructures with annealing twins (ATs) to enhance the strength of Cu–15Sn-0.3Ti alloy without loss of elongation. The experimental results indicated that the combination method of Rotary swaging (RS) and Electric pulse treatment (EPT) could induce recrystallization of deformed microstructure to refine the average grain size of the HA state sample from≥500 μm to 9.3 μm, and the UTS and YS were increased by 34 % and 28 %, respectively. It is worth noting that this process was completed in only 90 s. The relationship between the changes in mechanical properties of Cu–15Sn-0.3Ti alloy and microstructure evolution during the EPT process was elucidated. The role of stacking faults (SFs) in the formation of ATs and recrystallization was revealed. The recrystallization efficiency of EPT and annealing treatment was compared by calculation.

Rapidly induced homogenization and microstructure control of Cu–15Ni–8Sn alloy by electropulsing treatment

The homogenization heat treatment is a key procedure to controlling the second phase, enhancing composition uniformity and workability of as-cast Cu–15Ni–8Sn alloy. Nonetheless, high annealing temperature and long holding time result in high energy consumption, high costs and severe oxidation. The effects of electropulsing treatment (EPT) and conventional homogenization treatment (CHT) on the microstructure and mechanical properties of Cu–15Ni–8Sn alloy by downward continuous casting were studied. The results showed that with increase of pulse current density, the treatment temperature of the alloy increased continuously. Subsequently, γ-(Cu, Ni)3Sn phase and lamellar (α+γ) phase underwent progressive spheroidizaiton and dissolution. Compared with CHT, EPT contributes to significant reductions in both treatment temperature (about 100 °C) and treatment time (1/34 of the CHT), the tensile strength decreased from 437 Mpa (as-cast alloy) to 380 MPa, while the elongation increased dramatically from 9.2 % to 41.6 %. Compared with being treated by CHT, the alloy treated by EPT performed excellent comprehensive mechanical properties. The extra free energy provided by EPT diminishes the thermodynamic energy barrier of γ phase dissolution and significantly accelerates atomic diffusion, which mainly contribute to rapid homogenization of Cu–15Ni–8Sn alloy by EPT at lower temperature. EPT can work as a novel homogenization heat treatment process for metallic materials, boasting advantages such as high efficiency, low energy consumption and low costs.

Photochemotherapeutic Properties of Cu(II) Complexes of L‐Lysine and L‐Arginine Appended to Anthracene

AbstractCu(II) complexes of positively charged amino acids L–Lysine and L‐Arginine appended to an anthracene unit and phenanthroline bases, namely [Cu(Anth‐Lys)(L)(ClO4)] (1, 2) and [Cu(Anth‐Arg)(L)(ClO4)] (3, 4) where L is 1,10‐phenanthroline (phen, 1 and 3), dipyrido[3,2‐a : 2′,3′‐c]phenazine (dppz, 2 and 4) were synthesized and fully characterized by various spectral and analytical methods. Cu(II) centered broad and weak d‐d band in the visible region along with phenanthroline based π→π* and n→π* bands in the UV region were observed in the electronic spectra of the complexes recorded in DMF‐Tris‐HCl buffer (1 : 4 v/v) (pH 7.2). The complexes 1–4 show efficient DNA binding propensity. They also demonstrated strong binding affinity for human serum albumin (HSA). The complexes showed efficient visible light‐induced cytotoxicity against A549 (human lung carcinoma), HaCaT (human epidermal keratinocytes) and MDA‐MB‐231(human breast cancer cells) cells with low dark toxicity. They generate both singlet oxygen (1O2) and hydroxyl radical (⋅OH) as reactive oxygen species (ROS) upon excitation with visible light which is believed to be responsible for killing cancer cells. Significant changes in the nuclear morphology of the HaCaT cells were observed when treated with complexes 2 and 4 in visible light compared to the non‐irradiated cells.

Replacing copper in composites with waste foundry sand: A novel approach for Cu-free resin-based braking material

Cu-free resin-based brake material filled with waste foundry resin-bonded sand (waste sand) was prepared using the hot-pressing method. The changes in the physical and chemical properties of Cu and waste sand during braking were investigated, and their role in resin-based composites was discussed. The effects of the content of waste sand on the hardness, impact strength, indentation hardness, elastic modulus, friction coefficient, wear rate, micro-scratch friction coefficient, scratch depth, residual depth, and wear mechanism of resin-based brake material were investigated. Cu-contained composites generate Cu2O when braking at high temperatures, which adversely affects the friction and wear properties. Compared to Cu, waste sand was found to be more favorable for the overall friction and wear properties of resin-based composites. This suggests that waste sand can be used as a substitute for Cu in brake material. Waste sand is beneficial for improving the friction coefficient and stability of brake material through the formation of a friction layer. This layer can significantly impact the wear mechanism of brake material, particularly at high temperature (250–350 ℃). The brake material with 10–15% waste sand indicates excellent heat-fade resistance.

Effect of laser power on the microstructure, shape memory effect and mechanical properties of Cu–13Al–5Fe high temperature shape memory alloy by laser powder bed fusion

Effect of laser power on the microstructure, shape memory effect and mechanical properties of Cu–13Al–5Fe high temperature shape memory alloy by laser powder bed fusion

Precipitation strengthening of Cu–Ni–Si-based alloys: Experimental and computational insights

The effects of interfacial energy on precipitation behavior and physical properties of Cu–Ni–Si–(Co) alloys were investigated. The Cu–1.3Ni–0.3Si and Cu–1.3Ni–0.6Si–1.0Co alloys (in weight %) were prepared by combined cold-rolling and aging processes. The addition of Co promoted the formation of (Ni,Co)2Si by replacing Ni with Co in Ni2Si. Ab initio calculations demonstrated that the small addition of Co considerably reduced the interfacial energy between the Cu matrix and (Ni,Co)2Si, which effectively decreased the activation energy for precipitation. As a result, the precipitation of fine rod-shaped (Ni,Co)2Si was accelerated during the aging process and the number density of the precipitates increased up to 9.0 × 1010 cm−2. The nano-scale (Ni,Co)2Si precipitates with an average size of 13.5 nm strengthened the alloy properly through the Orowan mechanism without much loss of electrical conductivity. The maximum hardness and electrical conductivity were 220 Hv and 51 % International Annealed Copper Standard, respectively, for the Cu–1.3Ni–0.6Si–1.0Co alloy aged for 4 h at 420 °C.

Effect of Ti on the microstructure and properties of Cu–Cr alloy

Cu–Cr–Ti alloy was successfully prepared by vacuum melting, solution treatment at 960 °C for 1 h, 80 % cold rolling and aging at 500 °C for 1 h. The effect of Ti content on the microstructure was characterized by Scanning electron microscope (SEM) and Transmission electron microscope (TEM). Their tensile strength, electrical conductivity, thermal stability, wear resistance and arc erosion resistance were also measured. The results showed that Ti can form the Ti0.77S phase with S, which can prevent the occurrence of sulfur embrittlement. And Ti can segregate around the Cr precipitates, hindering their growth. Therefore, the tensile strength, hardness, high temperature softening resistance, wear resistance and arc erosion resistance improved with the increase of Ti content. But the electrical conductivity decreased sharply since Ti was mainly solidly dissolved in the matrix. What's more, the electrical conductivity decreased sharply and other properties did not improve when the content increased from 0.066 wt% to 0.098 wt%, that is, the comprehensive performance was the best when the Ti content was 0.066 wt%. The tensile strength was 551 MPa, electrical conductivity was 78.3%IACS and the friction coefficient was 0.33. This work provides effective ideas for preparing copper alloys with desired properties.

Extracting mechanical and microstructural properties of Cu–Zr thin film alloys by MEMS, AFM and ellipsometer

The quantification of the atomic concentration ratios of thin-film metallic alloys having low atomic ordering is challenging, particularly if they are grown on similar metals and possess different surface chemistries. Micromechanical and optical methods have been used to correlate the elemental ratios with the mechanical and optical properties of the films. The room-temperature growth of Cu–Zn thin-film alloys with varying elemental ratios on cosputtered Si substrates was performed to obtain an amorphous film structure. X-ray diffraction patterns confirmed that the grown films exhibited a very short range ordering, suggesting an amorphous structure. The mechanical properties of the films evaluated using microelectromechanical system (MEMS) indicated that the alloy films with moderate Zr concentrations had lower surface stress compared to those with low and high Zr concentrations. Furthermore, spectroscopic ellipsometry was employed to qualitatively assess the relaxation times of free carriers. The results demonstrated a strong correlation between the relaxation times and surface roughness measurements, showing that the microstructure and resistivity characteristics of the alloys align with the Nordheim semiempirical model. The extinction coefficient of the binary alloy film linearly depends on the metallic bulk concentration ratio in a specific metallic ratio range, paving the way for realizing qualitative elemental percentage assessment in the field of metrology.

Effect of alloying element Zr on microstructure and properties of Cu−Y2O3 composites

Cu−Y2O3 and Cu−Y2O3−Zr composites were prepared via mechanical alloying and spark plasma sintering, and their microstructure and properties were systematically studied by using optical metalloscope, scanning electron microscope, transmission electron microscope, conductivity and tensile tests. It is found that the microstructure of the composites greatly affects mechanical behavior and electrical conductivity. The improvement of electrical property can be attributed to the formation of coherent Y4Zr3O12 particles and the preferential nucleation of Cu4Zr phase, which improves the interface between Y2O3 and Cu matrix, and reduces the dislocation density, respectively. In addition, the Cu−Y2O3−Zr composites can achieve 265.6 MPa of yield strength, 301.0 MPa of ultimate tensile strength, 23.6% of elongation, and 92.0%(IACS) of electrical conductivity.

Effect of Cu doping on structural and magnetic properties of Cu x Zn1-x Fe2O4 nanoparticles for biomedical applications

Nano-ferrites with chemical equation Cu x Zn1-x Fe2O4 (x = 0.1, 0.2, 0.3, 0.4, 0.5, 0.6 and 0.7) were prepared by sol–gel auto-combustion method to study structural and magnetic properties along with antibacterial and antifungal activity. The samples are sintered in air at 400 °C for 4 h. The samples are characterised by x-ray diffraction (XRD), ultraviolet (UV), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), energy dispersive X-ray (EDX), and vibrating-sample magnetometry (VSM) tools. Presence of some secondary phases are noticed in the samples. XRD data is utilised to calculate lattice parameter, crystallite size, lattice strain, and density of ferrite samples. The crystallite size varies between 6.3 and 7.7 nm and lattice strain has value between 0.11–0.15. Also, VSM is used to calculate saturation magnetisation, coercivity and remanent magnetisation of synthesised samples. The saturation magnetisation as high as 32.8 emu g−1 is obtained for x = 0.7 composition. The magnetic Cu x Zn1-x Fe2O4 nanoparticles have shown good antibacterial and antifungal activity.

First-Principles Study of the Effect of Sn Content on the Structural, Elastic, and Electronic Properties of Cu–Sn Alloys

In order to explore the mechanism of the influence of Sn contents on the relevant properties of Cu–Sn alloys, the structure, elasticity, electronic, and thermal properties of Cu–Sn alloys doped with different proportions of Sn (3.125 at%, 6.25 at%, and 9.375 at%) were established using the first-principles calculation based on density functional theory. Firstly, their lattice constants and Sn concentration comply with Vegard’s Law. From the mixing enthalpy, it can be seen that Sn atoms can be firmly dissolved in the Cu matrix, and the structure is most stable when the Sn content is 3.125 at%. In addition, the introduction of mismatch strain characterized their solid solution strengthening effect. The elastic and electronic properties showed that when the Sn content is 6.25 at%, the Cu–Sn alloy has the best plasticity and the highest elastic anisotropy; when the Sn content is 3.125 at%, the Cu–Sn alloy is the most stable and has stronger bulk and shear modulus, which was mainly due to a stronger Cu-Cu covalent bond. Finally, the Debye temperature, thermal conductivity, and melting point were calculated. It is estimated that the thermal conductivity of Cu–Sn alloy is relatively good when the Sn content is low.

Preparation, micro-structure and characterization of high strength and low profile lithium copper foil with SPS and HP additives

Copper foil is an important negative current collector material for lithium ion battery. Its mechanical properties and appropriate roughness have an important influence on the negative electrode and battery performance. Adding additives to the plating solution is an effective means to improve the performance of lithium copper foil. Here we prepared Cu-(SPS + HP) copper foil with a tensile strength of 570.57 MPa, elongation of 4.47%, and roughness of 0.812 μm. Moreover, the optical contact angle test shows that Cu-(SPS + HP) has the best surface wettability (the highest surface energy 50.62 mN/m). XRD and EBSD tests show that the fundamental reason for improving the mechanical properties of Cu-(SPS + HP) is the preferred orientation of the crystal plane (220) and the phenomenon of large grains including small grains. Besides, the electrochemical test of Cu-(SPS + HP) bath is conducted to determine the principle of additives in the plating process, cathodic reaction characteristics and electrocrystallization nucleation mechanism. Finally, we establish the electrodeposition model. The reaction behavior of SPS and HP in the plating process synergistically promoted the preparation of excellent performance lithium copper foil.

Study on discontinuous precipitation behaviour and performance change of Cu–Ti–Ni during aging

ABSTRACT The discontinuous precipitation behaviour and properties of Cu–Ti–Ni alloy during aging precipitation were studied by means of electron backscatter diffraction (EBSD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results show that β'-Cu4Ti was formed in the matrix during the aging process of Cu–4Ti–1Ni alloy, and the cellular structure grows at the grain boundary in the form of discontinuous precipitation in the middle and late stages of aging, and expands to the interior of the grains with the aging time until the grains were completely covered, then a uniform Cu3Ti structure was formed. In addition, the coverage area of cellular tissue increases with aging time and temperature. Under different aging temperature conditions, the hardness of the alloy increases first and then decreases with the aging time, with a peak value of 319.8 HV and a strength of 782.2 MPa. The electrical conductivity increases rapidly and then increases slowly with aging time, reaching 15.5 IACS after aging at 500°C for 10 h. Based on the Avrami equation, the kinetic analysis of discontinuous precipitation at different temperatures was established.

Effect of ECAP by Route BC and Aging Heat Treatment on the Structure and Properties of Cu0.4Cr0.3Zr Alloy

Effect of ECAP by Route BC and Aging Heat Treatment on the Structure and Properties of Cu0.4Cr0.3Zr Alloy