Copper Composites Research Articles

A Study of the Microstructure and Properties of Copper Composites Reinforced with Co – Ti

A Study of the Microstructure and Properties of Copper Composites Reinforced with Co – Ti

光触媒を用いたダイヤモンドのアミノ基修飾と銅基質に対する高分散複合化技術

We strove to produce a microdiamond（MD）- copper composite by electroplating. Unfortunately, copper is naturally non-wetting with MD because of their chemical incompatibility. We achieved modification of the amino group for the MD surface using a photocatalytic treatment, followed by electroplating of the copper. Results demonstrated that the MD - copper composite material assisted by photocatalysis markedly improved their interfacial affinity and thermal conductivity.

Bi-metal composite material for plastic injection molding tooling applications via fused filament fabrication process

Metal fused filament fabrication (FFF) technology uses metal powder filled plastic filaments, coupled with debinding and sintering operations, to produce metal parts. This study builds upon FFF technology, combining the technique with melt infiltration to create a structure that retains the surface hardness of tool steel while also benefiting from the thermal conductivity of copper. We observe excellent wettability of the copper to the steel, a complete filling of the as-sintered steel infill free volume, and diffusion of iron and chromium into copper. To demonstrate a practical use of the process, an injection mold with conformal channels is shaped using the technology. The bi-metal composite of steel and copper exhibited a thermal conductivity of 108 W/mK and a modulus of elasticity of 145 GPa in an as-manufactured condition.

Effect of Functionalized Multi-Walled Carbon Nanotubes on Preparation of High Strength and Conductive Copper-CNTs Composites by Electrodeposition

Functionalized multiwalled carbon nanotubes (MWCNTs)-reinforced copper (Cu) composites were prepared by the combination of electrowinning and hot-pressing sintering and cold rolling process. The influence of the functionalization of MWCNTs on the strength and electrical properties of MWCNTs/Cu composites was studied. Functional group was introduced to increase the wetting of water electrolytes, improve the poor wettability of MWCNTs and form a highly active surface suitable for the preparation of MWCNTs/Cu composites by electro-deposition, enabling MWCNTs to be evenly dispersed in Cu matrix. Studies have shown that the addition of 1% of functionalized MWCNTs composite can increase the tensile strength by 6% and 165% compared with the addition of unfunctionalized and pure copper. It’s worth noting that the increase of oxygen-containing functional group brought about by functionalized MWCNTs did not significantly reduce the electrical properties of composites. The main reason for this is the good dispersion of the treated MWCNTs in Cu matrix and the bridging for electronic transmission, ensuring that the high electrical properties of MWCNTs/Cu composites are just slightly lower than those of electrolytic pure copper (99.92% IACS).

Influence of Carbon Nanotube Attributes on Carbon Nanotube/Cu Composite Electrical Performances

Carbon nanotube (CNT)/copper composites offer promise as lightweight temperature-stable electrical conductors for future electrical and electronic devices substituting copper. However, clarifying how constituent nanotube structures influence CNT/Cu electrical performances has remained a major research challenge. Here, we investigate the correlation between the CNT/Cu electrical performances and nanotube structure by preparing and characterizing composites containing nanotubes of different structural attributes. We prepared three types of composites—single-wall (SW)-CNT/Cu wires, SW-CNT/Cu pillars, and multi-wall (MW)-CNT/Cu wires. The composites were fabricated from the corresponding CNT templates by two-step Cu electrodeposition, which retains template nanotube attributes through the fabrication process. The nanotube characteristics (diameter, G/D, alignment, etc.) in each template as well as the internal structure and electrical performances of the corresponding composites were characterized. SW-CNT/Cu wires and pillars outperformed MW-CNT/Cu wires, showing ≈ 3× higher room-temperature four-probe conductivities (as high as 30–40% Cu-conductivity). SW-CNT/Cu also showed up to 4× lower temperature coefficients of resistances i.e., more temperature-stable conductivities than MW-CNT/Cu. Our results suggest that few-walled small-diameter nanotubes can contribute to superior temperature-stable CNT/Cu conductivities. Better CNT crystallinity (high G/D), fewer nanotube ends/junctions, and nanotube alignment may be additionally beneficial. We believe that these results contribute to strategies for improving CNT/Cu performances to enable the real-world application of these materials as Cu substitutes.

Fabrication, Microstructure, and Properties of In Situ V2C-Reinforced Copper Composites

In this paper, in situ V2C-reinforced Cu composites were successfully fabricated by hot pressing at 750 °C under 25 MPa using Cu and V2SnC powders. Due to decomposition of V2SnC to V2C and Sn during sintering, Sn atoms entered the crystal structure of Cu. Therefore, final compositions of composites consisted of Cu(Sn) and V2C phases. Here, copper composites with 0, 5, 10, 20, and 30 vol.% V2C were designed. Their microstructures and physical and mechanical properties were systematically investigated. It was observed that with increasing V2C content, electrical conductivity decreased from 0.589 × 108 S·m−1 to 0.034 × 108 S·m−1 and thermal conductivity decreased from 384.36 W⋅m−1⋅K−1 to 24.65 W·m−1·K−1, while Vickers hardness increased from 52.6 HV to 334 HV. Furthermore, it was found that composites with 20 vol.% V2C had the highest tensile strength (440 MPa).

Peroxymonosulfate activation using a composite of copper and nickel oxide coated on SBA-15 for the removal of sulfonamide antibiotics

The sluggish Ni(II)/Ni(III) redox cycle does not benefit perxymonosulfate (PMS) activation for recalcitrant pollutant degradation. To solve this problem, a heterogeneous catalyst, Cu0.2Ni0.8O/SBA-15 (CNS), was constructed to activate PMS for decomposing two sulfonamide antibiotics, sulfachlorpyridazine (SACP) and sulfapyridine (SAP). SACP and SAP were completely degraded over Cu0.2Ni0.8O/SBA-15/PMS (CNSP) after 90 min. O2.- was the dominant active species involved in the degradation of SACP and SAP. Structural analysis and elemental valence state observations indicated that Cu(Ⅰ) provided electrons through Cu–O–Ni bonds to realize the charge compensation for Ni(Ⅲ) in the CNSP system. Thus, the in situ Cu(I)/Cu(II) promoting the Ni(II)/Ni(III) cycle could accelerate the PMS activation. This work provides new insights into the electron transfer between transition metals and the charge compensation mechanism for PMS activation. The degradation mechanism was proposed based on the XPS results before and after the reaction, a radical quenching test, and an EPR test. Combined with the SACP and SAP degradation intermediates identified by LC-MS, we suggest that the choice of treatment process depends on the occurrence of a steric hindrance effect between the molecular structure of the degradation target and free radicals.

Phenylamine-Functionalized Graphene–Copper Composites with High Thermal Conductivity: Implications for Thermal Dissipation

Developing highly efficient thermal management techniques is crucial in order to achieve the best performance of electronic equipment. Here, a delocalized conjugated system was established by the conjugation of sp2 orbitals in phenylamine groups and a delocalized big π bond in graphene to construct an electron thermal conduction route. Then, the abundant π electrons in graphene can be transferred to the adjacent copper unimpededly, leading to a remarkable thermal conductivity. These results demonstrate that the copper substrate deposited with phenylamine-functionalized graphene (PA–Gr–Cu) shows a high thermal conductivity of 506 W m–1 k–1, which is 30.8 and 44.2% higher than those of the pristine graphene–copper composite (Gr–Cu) and copper (Cu), respectively. Placed on a heat source heated from 30 to 210 °C within 5 min, the top surface temperature of PA–Gr–Cu increases to 198 °C rapidly, whereas those of Gr–Cu and Cu only increase gently to 88 and 59 °C. This work demonstrates that phenylamine with a pair of lone electrons in the N atom shows superiority as an intermediate molecule to link graphene and copper to establish a delocalized conjugated system. This innovation provides another solution to establish a conjugated structure between graphene and copper to construct an electron thermal conduction route with remarkable thermal conduction properties and will promote the research on the electron thermal conduction route for graphene-based metal matrix composites in the application of thermal dissipation.

Characterization of Sn-Sb-Ti Solder Alloy and the Study of Its Use for the Ultrasonic Soldering Process of SiC Ceramics with a Cu-SiC Metal-Ceramic Composite.

The aim of this research was to characterize soldering alloys of the type Sn–Sb–Ti and to study the ultrasonic soldering of SiC ceramics with a metal–ceramic composite of the type Cu–SiC. The Sn5Sb3Ti solder exerts a thermal transformation of a peritectic character with an approximate melting point of 234 °C and a narrow melting interval. The solder microstructure consists of a tin matrix, where the acicular constituents of the Ti6(Sb,Sn)5 phase and the sharp-edged constituents of the TiSbSn phase are precipitated. The tensile strength of the soldering alloy depends on the Ti content and reaches values from 34 to 51 MPa. The average strength of the solder increases with increasing Ti content. The bond with SiC ceramics is formed owing to the interaction of titanium, activated by ultrasound, with SiC ceramics, forming the (Ti,Si)6(Sb,Sn)5 reaction product. The bond with the metal–ceramic composite Cu–SiC is formed owing to the solubility of Cu in a tin solder forming two phases: the wettable η-Cu6Sn5 phase, formed in contact with the solder, and the non-wettable ε-Cu3Sn phase, formed in contact with the copper composite. The average shear strength of the combined joint of SiC/Cu–SiC fabricated using the Sn5Sb3Ti solder was 42.5 MPa. The Sn–Sb–Ti solder is a direct competitor of the S-Bond active solder. The production of solders is cheaper, and the presence of antimony increases their strength. In addition, the application temperature range is wider.

Copper-Carbon Nanotubes Composite Materials for Lightning Strike Protections in Airplanes

The structures of airplanes are nowadays including more and more non electrically conductive plastics parts. To mitigate the damages after lightning strike events, copper meshes are integrated into the fuselage to provide it with electrical conductivity. Yet, although copper has one of the best electrical and thermal conductivities, its density remains high compared to materials like Aluminium (8.96 g.m-3 for Copper ; 2.7 g-m-3 for Aluminium) and R&D efforts are needed to develop new materials with higher specific electrical conductivity and ampacity. In 2013, Subramaniam et al.1 reported the fabrication of Copper/Carbon nanotubes (Cu-CNTs) composites with a similar specific conductivity than the one of copper and an ampacity increased by two orders of magnitude.The talks will describe an original fabrication method of Cu-CNTs composites based on electroplating and entirely realized without any hazardous organic solvents. Their electrical behaviour (conductivity as well as ampacity) will be described as well as a first evaluation of their lightning strike protection (LSP) properties. The lightning strike damages observed on pristine and Cu-CNTs samples consist of concentric vaporized zones more or less extended depending of samples. Interestingly, for some Cu-CNTs composites, partial or no vaporization is observed with a preserved electrical conductivity of the samples.Subramaniam, C., Yamada, T., Kobashi, K. et al. One hundred fold increase in current carrying capacity in a carbon nanotube–copper composite. Nat Commun 4, 2202 (2013).

Precise localization of contaminants in graphene with secondary ion mass spectrometry

Integration of graphene with the existing fabrication lines may be possible only if the growth process fulfills the high purity requirements of the front-end-of-line integration approaches. While many analytical techniques may provide information about the concentration of contaminants, their dimensional sensitivity is usually poor and thus it is not possible to assess which contaminants are located above/below graphene and which are incorporated into its structure. In this work, an optimized secondary ion mass spectrometry measurement procedure that combines excellent detection limits (0.8–2.9 ppm) and subnanometer depth resolution is presented. It confirms the presence of sodium and sulfur at the surface of the graphene layer, the formation of graphene–copper composite, and allows the detection of molybdenum and tungsten at the interface between graphene and the germanium substrate. Such precision may prove to be valuable for further optimization of the growth process of 2D materials.

Thermal properties and failure mechanism of graphene nanoplatelet-reinforced copper composites fabricated using electroless plating

Copper matrix composites reinforced with graphene nanoplatelets (GNPs) were fabricated using an electroless plating method, and the effects of the GNP content on the thermal conductivity (TC), coefficient of thermal expansion (CTE), and mechanical properties of the composites were studied. The TC, CTE, and strength of the composites were measured in the in-plane and through-plane directions and compared. Increasing the GNP content in the GNP/Cu composite was effective in reducing the CTE and increasing the compressive yield strength of the composite. The compressive yield strength was higher in the through-plane direction, but the maximum compressive strength was higher in the in-plane direction. In the case of compressive deformation in the in-plane direction, a single shear fracture with one fracture direction occurred. The compressive deformation in the through-plane direction of the composite with high GNP content (15% and 20%) exhibited a duplex shear fracture with two fracture directions. The significant findings of the present study are that it is possible to fabricate GNP/Cu composites with uniformly dispersed GNPs and low porosity by electroless plating. In addition, the failure mechanism of GNP/Cu composites was revealed for the first time.

Interface microstructure morphology and formation evolution mechanism of Al-1060/Cu-T2 composites fabricated by explosive welding method

ABSTRACT Aluminum–copper composite is an attractive candidate for electronic industry and power industry because of excellent electrical and thermal conductivity. In this work, the explosive welding technique was successfully employed to prepare the Al/Cu composite. The interface microstructure morphology was characterized using the optical microscopy (OM), field emission scanning electron microscopy (FSEM) and electron backscatter diffraction (EBSD). Meanwhile, the interface formation evolution process was simulated using smoothed particle hydrodynamics (SPH) method by ANSYS/LS-DYNA software. The experimental results indicated that the joining interface presents a typical wavy structure and formed melted zones in the vortex region. The formation of intermetallic compounds and strong texture were confirmed at the vortex region. The simulation results revealed the interface formation evolution characteristics and mechanism, and obtained a wavy joining interface, which are in good agreement with experimental results.

A novel Cu-Gr composite electrode development for electric discharge machining of Inconel 718 alloy

Requirement of processes with high productivity leads to the development of new tools and machining technique. One such attempt was made to develop a Copper Composite (CC) tool reinforced with graphite particles through the stir casting route. The CC tool was utilized to machine the Inconel 718 alloy using Electric Discharge Machining (EDM) technique by varying input variables viz tool material, discharge current, pulse on time, pulse off time and gap distance. Brass, Copper, Copper—5% Graphite (CG5), Copper—10% Graphite (CG10), Copper—15% Graphite (CG15) are the various used tool material whereas Material Removal Rate (MRR), Tool Wear Ratio (TWR) and Surface Roughness (Ra) were recorded as responses. The results revealed that using the CG10 and CG15 tools causes arcing and open circuit under some parametric conditions. CG5 offers best MRR and least TWR owing to the bridging effect, high thermal conductivity and lesser density which was suitable for roughing operation whereas brass offers least Ra which was recommended for finishing operation. The surface topography was analyzed with the aid of Scanning Electron Microscope (SEM). Micro crack, pock marks, globules and remelted layers are some of the defects observed in surface morphology. The process parameters was optimized using VIKOR technique.

Experimental and numerical study of an overlay composite absorber plate material for a solar air heater

Abstract The research in this paper is a sequel of an earlier work by the author in which experimental and CFD results were compared for an absorber plate made of iron with and without fins for two flow rates. The research yielded a good comparative result between the experimental and computational process for an optimized flow rate and the effect of the fins. The objective of this paper is to verify the effect of the overlay composite absorber plate material on a solar air heater through experimental and computational fluid dynamics. The experimental setup consists of an absorber plate as an overlay composite of aluminum and copper for enhanced heat transfer. Experiments and CFD analysis were done in three configurations. In configuration one, only the aluminum absorber plate with fins was considered. In configuration two, the overlay composite was considered with copper on the top and aluminum at the bottom as fins, and in configuration three, the overlay composite was considered with aluminum at the top and copper at the bottom as fins. A transient 8 hours CFD analysis was carried out using these configurations. While validating the results it was found that the overlay absorber plate Cu-Al was capable of generating a high outlet temperature Max of 88 °C and capable of generating 83 °C air for 5 hours and had good thermal efficiency when compared to the other materials in the other two configuration. It was found that experimental and computational analysis were in very close agreement, and the margin of error between the experimental and computational processes was less than 8 %.

Unsymmetrical Pyrazoly‐Pyridinyl‐Triazole Promoted High Active Copper Composites on Mesoporous Materials and Catalytic Applications

AbstractHigh active ligand usually plays an important role during catalysis and organic synthesis area. Unsymmetrical tridentate pyrazoly‐pyridinyl‐triazole ligand bridged copper composite supported on the ordered mesoporous material was synthesized from the designed ligand, simple copper salt and commercially available SBA‐15. The resulting copper composite was fully characterized by X‐ray photoelectron spectrometry, scanning electron microscopy and transmission electron microscopy and X‐ray power diffraction. Compared to traditional noble Ir, Ru, Rh and Pd complexes, this economical and stable heterogeneous copper revealed high catalytic selectivity for the reaction of hydronaphthalenones and alcohols with good recyclability. Mechanism explorations disclosed that oxidation, condensation and hydrogenation processes were all involved during this process and this provided an efficient method to the synthesis of 2‐benzyl‐3,4‐dihydronaphthalen‐1(2H)‐onederivatives with good recyclability through the green borrowing hydrogen strategy.

Swift isotropic heat transport of 3D graphene platform-based metal-graphene composites

Despite the remarkable thermal properties of graphene, the heat transport along the z-axis is intrinsically limited by the van der Waals interactions, leading to thermal anisotropy in multilayered graphene (or graphite) and its composites. Herein, we report a graphene foam (GF) with three-dimensional (3D) pore structure-based metal composites with excellent isotropic thermal conductivity and fast heat transfer performance. The 3D periodic structure of the GF–copper composites composed of high-quality multilayer graphene and copper was formed via a chemical vapor deposition (CVD) and a spark plasma sintering (SPS) process. The high-quality graphene layers in GF were well-bonded to copper, forming a clear interface without voids in the consolidated composites. Owing to the uniform 3D interconnection of graphene layer in the GF, in spite of less than 1 vol% carbon in the copper matrix, the GF–copper composites showed high isotropic thermal conductivity, which was higher by about 11 and 6% for in-plane and through-plane, respectively, than those of the bulk copper (∼400 W m−1 K−1). The superior performance of the 3D graphene-based metal–carbon composites offers remarkable opportunities in thermal management for advanced electronic and optoelectronic devices requiring high power density and efficiency.

Geometrical optimization of boron arsenide inserts embedded in a heat spreader to improve its cooling performance for three dimensional integrated circuits

This investigation is aimed at the design and optimization of boron arsenide insert structures embedded in the heat spreader of a 3-D Integrated Circuit (IC). The inserts are distributed in three main configurations: radial, one level of pairing, and two levels of pairing. The considered heat spreader is constituted of a composite of copper and highly conductive blades made of boron arsenide with high thermal conductivity. The structures corresponding to the lowest maximum temperature of the 3-D IC while the ratio of the boron arsenide volume to the whole heat spreader volume is fixed, are established. Four different boundary conditions are examined to seek their impact on the optimal configuration of the inserts. The results show that for the constant temperature, variable temperature, convection heat transfer boundary conditions at optimal conditions, the maximum temperature of the whole structure (the structures have not been defined) can be reduced by 13.7%, 11.9%, and 13.9%, respectively; while the size of the plain heat spreader (without HCI) was 200% larger than the recommended HCI embedded one.

Investigation of in-situ synthesis of alumina reinforcement and comparative flexural behavior with respect to ex-situ Al2O3 reinforced copper composite

Ex-situ and in-situ reinforced copper matrix composite samples containing 1.1 wt. % and 2 wt. % Al2O3 were produced by spark plasma sintering (SPS) at 830 °C and holding time of 30 min. In-situ reinforced sample was synthesized by a novel technique using the reaction between ball-milled copper oxide and Cu-10 wt. % Al filings as the additive and copper powder. The in-situ formation of alumina reinforcement was confirmed by SEM observation and EDS analysis. Morphology and distribution of reinforcement phase in different composite samples were studied. The in-situ reinforced composite sample showed superior flexural fracture strength and strain (349 MPa and 0.027, respectively). Different patterns of crack propagation were observed in the SEM images of fracture surfaces: the reinforcement’s interface path (due to the formation of undesired oxide phase) was dominant in the ex-situ samples, while the interface of in-situ reinforcements remained intact and the cracks originated in the agglomeration sites.

Novel nanocomposite of biochar-zerovalent copper for lead adsorption.

In this study, a composite of zerovalent copper-biochar was investigated for its ability to remove lead from water. The prepared material was characterized by using scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), X-ray diffractomter (XRD), and X-ray photoelectron spectroscopy (XPS). The pH effect on adsorption of lead was investigated within the range of 2-8 and the effect of temperature was studied at 303, 308, 313, and 318 K. The kinetics of lead adsorption on biochar composite was evaluated and the equilibrium time of 12 hr was established. To further evaluate the nature of adsorption, Langmuir model was tested and the adsorption capacities were evaluated for lead adsorption on the surface of copper biochar composite. The activation energy, entropy, and enthalpy values indicated the adsorption phenomenon to be chemisorptive and spontaneous in nature. Comparison of adsorption capacities with the reported adsorbents in the literature concluded zerovalent copper-biochar composite to be an efficient adsorbent for the removal of lead in the experimental conditions under study. RESEARCH HIGHLIGHTS: Highly efficient composite of zerovalent copper with biochar was synthesized for lead adsorption. XPS and XRD shows the presence of zerovalent copper in the biochar composite. pH and temperature were the main governing factors in the adsorption process. Adsorption capacity for lead is higher than many of the reported adsorbents.