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1
Ciupiński, Łukas, D. Siemiaszko, Marcin Rosiński, Andrzej Michalski e Krzysztof Jan Kurzydlowski. "Heat Sink Materials Processing by Pulse Plasma Sintering". Advanced Materials Research 59 (dicembre 2008): 120–24. http://dx.doi.org/10.4028/www.scientific.net/amr.59.120.
Testo completoAbstract (sommario):
A Pulse Plasma Sintering (PPS) process was employed to manufacture Cu-diamond composites with a 50% volume fraction of each constituent. Pure and Cr (0.8wt.%) alloyed copper matrices were used and commercial diamond powders. The composites were sintered at temperature of 900°C for 20 min and under pressure of 60 MPa. In these sintering conditions diamond becomes thermodynamically unstable. Cu0.8Cr-diamond and Cu-diamond composites with relative densities of 99,7% and 96% respectively were obtained. The thermal conductivity of Cu0.8Cr-diamond composite is equal to 640 W(mK)-1 whereas that of Cu-diamond is 200 W(mK)-1. The high thermal conductivity and relative density of Cu0.8Cr-diamond composite is due to the formation of a thin chromium carbide layer at the Cu-diamond interface.
2
Kim, Kyungju, Dasom Kim, Kwangjae Park, Myunghoon Cho, Seungchan Cho e Hansang Kwon. "Effect of Intermetallic Compounds on the Thermal and Mechanical Properties of Al–Cu Composite Materials Fabricated by Spark Plasma Sintering". Materials 12, n. 9 (10 maggio 2019): 1546. http://dx.doi.org/10.3390/ma12091546.
Testo completoAbstract (sommario):
Aluminium–copper composite materials were successfully fabricated using spark plasma sintering with Al and Cu powders as the raw materials. Al–Cu composite powders were fabricated through a ball milling process, and the effect of the Cu content was investigated. Composite materials composed of Al–20Cu, Al–50Cu, and Al–80Cu (vol.%) were sintered by a spark plasma sintering process, which was carried out at 520 °C and 50 MPa for 5 min. The phase analysis of the composite materials by X-ray diffraction (XRD) and energy-dispersive spectroscopy (EDS) indicated that intermetallic compounds (IC) such as CuAl2 and Cu9Al4 were formed through reactions between Cu and Al during the spark plasma sintering process. The mechanical properties of the composites were analysed using a Vickers hardness tester. The Al–50Cu composite had a hardness of approximately 151 HV, which is higher than that of the other composites. The thermal conductivity of the composite materials was measured by laser flash analysis, and the highest value was obtained for the Al–80Cu composite material. This suggests that the Cu content affects physical properties of the Al–Cu composite material as well as the amount of intermetallic compounds formed in the composite material.
3
Xu, Jian, Pei Xian Zhu, Hui Yu Ma e Sheng Gang Zhou. "Characterisation of Ti-Al and Ti-Cu Laminated Composite Electrode Materials". Advanced Materials Research 194-196 (febbraio 2011): 1667–71. http://dx.doi.org/10.4028/www.scientific.net/amr.194-196.1667.
Testo completoAbstract (sommario):
We proposed using Ti-Al and Ti-Cu laminated composites instead of single Ti electrode metals, as well as studied the difference in performance between laminated composite electrode materials and pure-Ti electrode. The analysis of the conductivity and electrochemical performance of electrode matrix material indicates the result that the improvement of matrix material by using Ti-Al and Ti-Cu laminated composites, better performance for conductivity of electrode, and be beneficial to homogenize the electrode surface potential and current distribution and promote electrocatalytic activity between polar plates. Whereas comparison between Ti-Al and Ti-Cu laminated composites, Ti-Cu laminated composites is better in performance.
4
Koltsova, Tatiana, Elizaveta Bobrynina, Aleksei Vozniakovskii, Tatiana Larionova e Olga Klimova-Korsmik. "Thermal Conductivity of Composite Materials Copper-Fullerene Soot". Materials 15, n. 4 (14 febbraio 2022): 1415. http://dx.doi.org/10.3390/ma15041415.
Testo completoAbstract (sommario):
Copper-based composites strengthened with fullerene soot nanoparticles of 20–30 nm size in concentration up to 23 vol.% were prepared via two methods: mechanical mixing and molecular level mixing. The dependence of thermal conductivity on the carbon concentration was studied. Maxwell’s model describes well the change in the thermal conductivity of the composite obtained by molecular level mixing. However, thermal conductivity of the composite produced by mechanical mixing is significantly lower than the calculated values, due to structural inhomogeneity and residual stresses. Comparison of the thermal conductivity of Cu-fullerene soot composites with that of Cu-based composites described in the literature showed that the prepared materials are not inferior in thermal conductivity to composites containing carbon nanotubes, despite the fact that fullerene soot has a much lower thermal conductivity.
5
Sugianto, Sugianto, Ngurah Made Dharma Putra, Endah F. Rahayu, Wahyu B. Widayatno, Cherly Firdharini, Slamet Priyono e Didik Aryanto. "Synthesis, Characterization, and Electrochemical Performance of Reduced Graphene Oxide-Metal (Cu,Zn)-Oxide Materials". Indonesian Journal of Science and Technology 8, n. 2 (10 marzo 2023): 329–44. http://dx.doi.org/10.17509/ijost.v8i2.56065.
Testo completoAbstract (sommario):
The reduced graphene oxide (rGO) and metal (Cu,Zn)-oxide composites were prepared using a one-step hydrothermal technique. The role of (Cu,Zn)-oxide on the physical and electrochemical properties of the composite was investigated. The composite consists of various shapes of ZnO nanoflowers and micro-spheres, as well as Cu-oxide nanoflakes and octahedron-like shapes. The (Cu,Zn)-oxides were formed in between the rGO layers and observed in the rGO-ZnO, rGO-CuO, and rGO-CuO-ZnO composites. The presence of ZnO, CuO, and rGO within the composite structure is also confirmed by the analyses of crystal structure, microstructure, and surface functional groups. Some excess impurities remaining from the surfactant give considerable differences in the electrochemical performance of the composites. The specific capacitance values of the rGO, rGO-ZnO, rGO-CuO, rGO-(0.5CuO-0.5ZnO), and rGO-(0.25CuO-0.75ZnO) composites are 9.32, 58.53, 54.14, 25.21, and 69.27 F/g, respectively. The formation ofa double metal-oxide structure as well as their insertion into the rGO sheet can significantly improve the electrochemical properties of the supercapacitor.
6
Han, Ying, Sida Li, Yundong Cao, Shujun Li, Guangyu Yang, Bo Yu, Zhaowei Song e Jian Wang. "Mechanical Properties of Cu-W Interpenetrating-Phase Composites with Different W-Skeleton". Metals 12, n. 6 (25 maggio 2022): 903. http://dx.doi.org/10.3390/met12060903.
Testo completoAbstract (sommario):
In this work, copper–tungsten (Cu-W) composites with a cubic and rhombic dodecahedron W-skeleton were fabricated by the infiltration of Cu melt into a three-dimensionally printed W scaffold. The effects of the skeleton structure on the mechanical properties and energy-absorbing characteristics of the Cu-W interpenetrating-phase composite were investigated and compared with those of commercial Cu-W composite fabricated by powder metallurgy. The results indicated that the mechanical properties of the studied Cu-W interpenetrating-phase composites were mainly related to the properties of their ordered skeletons. Compared to the dodecahedron W-skeleton Cu-W composites, cubic-W-skeleton Cu-W composites exhibited higher strengths but lower absorbed energy. The Cu-W composites with ordered W-skeletons displayed much higher energy absorption than the commercial Cu-W ones. By adjusting the ordered W-skeleton structure contained in the composite, the strength and deformation behavior of the Cu-W composite can be effectively improved, which provides a guide to optimizing the mechanical properties and energy absorption of Cu-W composites.
7
Kim, Song-Mi, Woo-Rim Park e Oh-Heon Kwon. "The Strength and Delamination of Graphene/Cu Composites with Different Cu Thicknesses". Materials 14, n. 11 (31 maggio 2021): 2983. http://dx.doi.org/10.3390/ma14112983.
Testo completoAbstract (sommario):
This study analyzed the mechanical and fracture behavior of graphene/copper (Cu) composites with different Cu thicknesses by using molecular dynamics (MD) and representative volume element (RVE) analysis. Three graphene/Cu composite analytical models were classified as 4.8, 9.8, and 14.3 nm according to Cu thicknesses. Using MD analysis, zigzag-, armchair-, and z (thickness)-direction tensile analyses were performed for each model to analyze the effect of Cu thickness variation on graphene/Cu composite strength and delamination fracture. In the RVE analysis, the mechanical characteristics of the interface between graphene and Cu were evaluated by setting the volume fraction to 1.39, 2.04, and 4.16% of the graphene/Cu composite model, classified according to the Cu thickness. From their obtained results, whether the graphene bond is maintained has the greatest effect on the strength of graphene/Cu composites, regardless of the Cu thickness. Additionally, graphene/Cu composites are more vulnerable to armchair direction tensile forces with fracture strengths of 14.7, 8.9, and 8.2 GPa depending on the Cu thickness. The results of this study will contribute to the development of guidelines and performance evaluation standards for graphene/Cu composites.
8
Silvain, Jean François, Valérie Denis-Lutard, Pierre Marie Geffroy e Jean Marc Heintz. "Adaptive Composite Materials with Novel Architectures". Materials Science Forum 631-632 (ottobre 2009): 149–54. http://dx.doi.org/10.4028/www.scientific.net/msf.631-632.149.
Testo completoAbstract (sommario):
Today, there is a strong push to improve the thermal management of electronic components in order to increase the performance and the reliability of electronic devices. Up to now, most of the heat sinks are mainly made of Copper that presents a good thermal conductivity (TC) but a coefficient of thermal expansion (CTE) much higher than the ceramic of the DBC (direct bonding Copper). It induces interfacial thermal stresses and indeed it decreases the reliability of the global electronic system. Therefore, there is a strong need for the development of novel heat dissipation material having low CTE combined with high TC. Carbon fibres reinforced copper matrix offers a good compromise between thermo mechanical properties (i.e. CTE) and medium TC. In order to increase surface TC, pure Copper can be added on the top surface and/or on the bottom one of the composite heat sink playing the role of heat spreader for hot spots linked with the Si components. The fabrication technique of these materials is based on powder metallurgy technique. The thermal properties of adaptive materials, TC and CTE, have been measured for different Copper thicknesses and architectures ([C/Cu], [Cu – C/Cu] and [Cu – C/Cu – Cu]). Simulation of the TC and CTE have been performed and compared to the experimental results.
9
Wang, Qing Yun, Wei Ping Shen e Ming Liang Ma. "Mean and Instantaneous Thermal Expansion of Uncoated and Ti Coated Diamond/Copper Composite Materials". Advanced Materials Research 702 (maggio 2013): 202–6. http://dx.doi.org/10.4028/www.scientific.net/amr.702.202.
Testo completoAbstract (sommario):
Heat sink materials not only should have higher thermal conductivity, but also have smaller difference of thermal expansion with cooled material. diamond/copper composites were made by the powder metallurgy method. Vacuum slowly vapor deposition technique was employed to deposit a titanium film on diamond particles before mixing with Cu powder in order to improve the bonding strength between Cu and diamond particles during sintering. The thermal expansion of diamond/Cu d composite was measured in the temperature range from 50 to 600 °C. The results show that the titanium film on diamond improves the interfacial bonding and reduces the coefficient of thermal expansion (CTE) of Cu/diamond composites. The CTE of diamond/Cu composites decreases with increasing diamond volume fraction as the results of mixture rule and the intense restriction effect of diamond reinforcement on the copper matrix. The residual stresses and pores in the composites affect instantaneous thermal expansion of diamond/Cu composites.
10
Niu, Bing, Dongdong Xie, Yanxin Zhang, Yuxiao Bi, Yigui Li, Guifu Ding e Liyan Lai. "Morphology Control and Mechanism of Different Bath Systems in Cu/SiCw Composite Electroplating". Nanomaterials 14, n. 12 (18 giugno 2024): 1043. http://dx.doi.org/10.3390/nano14121043.
Testo completoAbstract (sommario):
With the rapid development of electronic technology and large-scale integrated circuit devices, it is very important to develop thermal management materials with high thermal conductivity. Silicon carbide whisker-reinforced copper matrix (Cu/SiCw) composites are considered to be one of the best candidates for future electronic device radiators. However, at present, most of these materials are produced by high-temperature and high-pressure processes, which are expensive and prone to interfacial reactions. To explore the plating solution system suitable for SiCw and Cu composite electroplating, we tried two different Cu-based plating solutions, namely a Systek UVF 100 plating solution of the copper sulfate (CuSO4) system and a Through Silicon Via (TSV) plating solution of the copper methanesulfonate (Cu(CH3SO3)2) system. In this paper, Cu/SiCw composites were prepared by composite electrodeposition. The morphology of the coating under two different plating liquid systems was compared, and the mechanism of formation of the different morphologies was analyzed. The results show that when the concentration of SiCw in the bath is 1.2 g/L, the surface of the Cu/SiCw composite coating prepared by the CuSO4 bath has more whiskers with irregular distribution and the coating is very smooth, but there are pores at the junction of the whiskers and Cu. There are a large number of irregularly distributed whiskers on the surface of the Cu/SiCw composite coating prepared with the copper methanesulfonate (Cu(CH3SO3)2) system. The surface of the composite is flat, and Cu grows along the whisker structure. The whisker and Cu form a good combination, and there is no pore in the cross-section of the coating. The observation at the cross-section also reveals some characteristics of the toughening mechanism of SiCw, including crack deflection, bridging and whisker pull-out. The existence of these mechanisms indicates that SiCw plays a toughening role in the composites. A suitable plating solution system was selected for the preparation of high-performance Cu/SiCw thermal management materials with the composite electrodeposition process.
11
Shi, Hailong, Xiaojun Wang, Xuejian Li, Xiaoshi Hu, Weimin Gan, Chao Xu e Guochao Wang. "Thin-Copper-Layer-Induced Early Fracture in Graphene-Nanosheets (GNSs)-Reinforced Copper-Matrix-Laminated Composites". Materials 15, n. 21 (1 novembre 2022): 7677. http://dx.doi.org/10.3390/ma15217677.
Testo completoAbstract (sommario):
The strength–ductility trade-off has been a long-standing challenge when designing and fabricating a novel metal matrix composite. In this study, graphene-nanosheets (GNSs)-reinforced copper (Cu)-matrix-laminated composites were fabricated through two methods, i.e., the alternating electrodeposition technique followed by spark plasma sintering (SPS) and direct electrodeposition followed by hot-press sintering. As a result, a Cu-GNS-Cu layered structure formed in the composites with various Cu layer thicknesses. Compared with the pure Cu, the yield strength of the GNS/Cu composites increased. However, the mechanical performance of the GNS/Cu composites was strongly Cu-layer-thickness-dependent, and the GNS/Cu composite possessed a brittle fracture mode when the Cu layer was thin (≤10 μm). The fracture mechanism of the GNS/Cu composites was thoroughly investigated and the results showed that the premature failure of the GNS/Cu composites with a thin Cu layer may be due to the lack of Cu matrix, which can relax the excessive stress intensity triggered by GNSs and delay the crack connection between neighboring GNS layers. This study highlights the soft Cu matrix in balancing the strength and ductility of the GNS/Cu-laminated composites and provides new technical and theoretical support for the preparation and optimization of other laminated metal matrix composites.
12
Jovanović, Milan T., Višeslava Rajković e Ivana Cvijović-Alagić. "Copper alloys with improved properties: standard ingot metallurgy vs. powder metallurgy". Metallurgical and Materials Engineering 20, n. 3 (30 settembre 2014): 207–16. http://dx.doi.org/10.5937/metmateng1403207j.
Testo completoAbstract (sommario):
Three copper-based alloys: two composites reinforced with Al2O3 particles and processed through powder metallurgy (P/M) route, i.e. by internal oxidation (Cu-2.5Al composite) and by mechanical alloying (Cu-4.7Al2O3 ) and Cu-0.4Cr-0.08Zr alloy produced by ingot metallurgy (vacuum melting and casting) were the object of this investigation. Light microscope and scanning electron microscope (SEM) equipped with electron X-ray spectrometer (EDS) were used for microstructural characterization. Microhardness and electrical conductivity were also measured. Compared to composite materials, Cu-0.4Cr-0.08Zr alloy possesses highest electrical conductivity in the range from 20 to 800 ℃, whereas the lowest conductivity shows composite Cu-2.5Al processed by internal oxidation. In spite to somewhat lower electrical conductivity (probably due to inadequate density), Cu-2.5Al composite exhibits thermal stability enabling its application at much higher temperatures than materials processed by mechanical alloying or by vacuum melting and casting.
13
Han, Tielong, Chao Hou, Yaochuan Sun, Yurong Li e Xiaoyan Song. "Effect of Grain Refinement on the Comprehensive Mechanical Performance of W–Cu Composites". Nanomaterials 13, n. 3 (18 gennaio 2023): 386. http://dx.doi.org/10.3390/nano13030386.
Testo completoAbstract (sommario):
W–Cu composites are commonly subjected to coupled multiple fields in service, which imposes high requirements on their overall performance. In this study, the ultrafine-grained W–Cu composite was fabricated using the combination of electroless plating and spark plasma sintering. The wear resistance and high-temperature compressive properties of the ultrafine-grained W–Cu composite were investigated and compared with those of the commercial coarse-grained counterpart. Moreover, the underlying strengthening and wear mechanisms were also discussed. Here we show that the ultrafine-grained W–Cu composite exhibits superior integrated mechanical performance, making it a potential alternative to commercial W–Cu composites.
14
Zhao, Yuchao, Nan Ye, Haiou Zhuo, Chaolong Wei, Weiwei Zhou, Jie Mao e Jiancheng Tang. "Influence of Pulse Current Forward-Reverse Duty Cycle on Structure and Performance of Electroplated W–Cu Composite Coatings". Materials 14, n. 5 (5 marzo 2021): 1233. http://dx.doi.org/10.3390/ma14051233.
Testo completoAbstract (sommario):
Tungsten-copper (W–Cu) composites are widely used as electrical contact materials, resistance welding, electrical discharge machining (EDM), and plasma electrode materials due to their excellent arc erosion resistance, fusion welding resistance, high strength, and superior hardness. However, the traditional preparation methods pay little attention to the compactness and microstructural uniformity of W–Cu composites. Herein, W–Cu composite coatings are prepared by pulse electroplating using nano-W powder as raw material and the influence of forward-reverse duty cycle of pulse current on the structure and mechanical properties is systematically investigated. Moreover, the densification mechanism of the W–Cu composite coating is analyzed from the viewpoints of forward-pulse plating and reverse-pulse plating. At the current density (J) of 2 A/dm2, frequency (f) of 1500 Hz, forward duty cycle (df) of 40% and reverse duty cycle (dr) of 10%, the W–Cu composite coating rendered a uniform microstructure and compact structure, resulting in a hardness of 127 HV and electrical conductivity of 53.7 MS/m.
15
Ji, Pu Guang, Dan Dan Qi, Fu Xing Yin, Gong Kai Wang, Elizaveta Bobrynina e Oleg Tolochko. "Effect of Nanocarbons Additions on the Microstructures and Properties of Copper Matrix Composite by Spray Drying Process". Key Engineering Materials 822 (settembre 2019): 202–7. http://dx.doi.org/10.4028/www.scientific.net/kem.822.202.
Testo completoAbstract (sommario):
Novel copper-nanocarbons – Cu-fullerene soot/reduced graphene oxide composites with 0-5 wt.% carbon additions were fabricated by spray drying method and hot pressing procedure. In order to obtain the homogeneity of composites, the spray drying integrating with shear mixing was adopted. The microstructure and properties of the composite materials were investigated and compared to Cu–graphite composite, which was prepared under the standard technology. The interface, depending on the nanocarbons addition, prevents copper aggregation, and inhibits the copper grain growth. The compact composites hardness was significantly higher as compared with Cu-CNTs and Cu-Graphite composites of the same carbon concentration with small reduction of the thermal conductivity.
16
Chmielewski, Marcin, Remigiusz Michalczewski, Witold Piekoszewski e Marek Kalbarczyk. "Tribological Behaviour of Copper-Graphene Composite Materials". Key Engineering Materials 674 (gennaio 2016): 219–24. http://dx.doi.org/10.4028/www.scientific.net/kem.674.219.
Testo completoAbstract (sommario):
In the present study, the influence of the volume fraction of graphene on the tribological properties of copper matrix composites was examined. The composites were obtained by the spark plasma sintering technique in a vacuum. The designed sintering conditions (temperature 950°C, pressing pressure 50 MPa, time 15 min) allowed obtaining almost fully dense materials. The tribological behaviour of copper-graphene composite materials was analysed. The tests were conducted using a CSM Nano Tribometer employing ball-on-plate tribosystem. The friction and wear behaviour of copper-graphene composite materials were investigated. An optical microscope, interferometer, and scanning electron microscope were used to analyse the worn surfaces. In friction zone, the graphene acts as a solid lubricant, which results in the increase in the content in the composites positively influencing the tribological characteristics of the steel- Cu-graphene composite.
17
Jia, Shanquan, Yu Su, Leandro Bolzoni e Fei Yang. "Interfacial bonding of chromium-doped copper/diamond composites fabricated by powder metallurgy method". International Journal of Modern Physics B 34, n. 01n03 (16 dicembre 2019): 2040050. http://dx.doi.org/10.1142/s0217979220400500.
Testo completoAbstract (sommario):
Copper/diamond composites can be used as heat-sink materials for high-power electronic devices due to their potential high thermal conductivity. However, it is challenging to obtain well-bonded interface between the copper matrix and the diamond particles. In this paper, we fabricated copper/diamond composites with [Formula: see text] wt.% of chromium additive ([Formula: see text], 3 and 7.4, and the corresponding composite was referred to as 1Cr-Cu/Dia, 3Cr-Cu/Dia and 7Cr-Cu/Dia, respectively) by hot forging of powder preforms. Results showed that only Cr3C2 interfacial layer formed between the copper matrix and the diamond particles for the 1Cr-Cu/Dia and 3Cr-Cu/Dia composites with a thickness of about 100 and 500 nm, respectively. A Cr/Cr3C2 dual layer interface formed in the 7Cr-Cu/Dia composite and its thickness was [Formula: see text]m. The coverage of diamond surface by the interface layer increased with increasing the adding amount of chromium in the composites. The 3Cr-Cu/Dia composite achieved the highest relative density and bonding strength, comparing to 1Cr-Cu/Dia and 7Cr-Cu/Dia composites, attributed to the formation of an optimal interface structure.
18
Chen, Cong, Zhenjie Zhai, Changfei Sun, Zhe Wang e Denghui Li. "Mechanical Properties of Ti3AlC2/Cu Composites Reinforced by MAX Phase Chemical Copper Plating". Nanomaterials 14, n. 5 (24 febbraio 2024): 418. http://dx.doi.org/10.3390/nano14050418.
Testo completoAbstract (sommario):
Among the various reinforcement phases available in Cu-based composites, the unique layered structure and easy diffusion of A-layer atoms make MAX phases more suitable for reinforcing a copper matrix than others. In this study, Cu-coated Ti3AlC2 particles (Cu@Ti3AlC2) were prepared through electroless plating, and Cu@Ti3AlC2/Cu composites were fabricated via vacuum hot-press sintering. The phase composition and microstructure of both Cu@Ti3AlC2 powder and composites were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results demonstrate the creation of successful electroless copper plating to obtain a Cu coating on Ti3AlC2 particles. At 850 °C, a small amount of Ti3AlC2 particles decompose to form TiCx, while Al atoms from the A layer of MAX phase diffuse into the Cu matrix to form a solid solution with Cu(Al). The test results reveal that the density of the Cu@Ti3AlC2/Cu composite reaches 98.5%, with a maximum compressive strength of 705 MPa, which is 8.29% higher than that of the Ti3AlC2/Cu composite. Additionally, the compressive strain reaches 37.6%, representing an increase of 12.24% compared to that exhibited by the Ti3AlC2/Cu composite.
19
Zhang, Li, Li Hua Dong, D. S. Wang, C. H. Fan e Y. Zhou. "A Survey on Electrode Materials for Electrical Discharge Machining". Materials Science Forum 697-698 (settembre 2011): 495–99. http://dx.doi.org/10.4028/www.scientific.net/msf.697-698.495.
Testo completoAbstract (sommario):
This work screens electrode materials used in EDM and proposes some potential electrodes for future industrial applications. Traditional graphite, W, and Mo EDM electrodes have low TWR due to their high melting points; while, Zn, brass, and Cu often experience too much tool wear. As to some newly developed alloy and composite materials, their machining performances depend on not only their melting points but also their microstructures. Cu-W alloy has high wear resistance but it is susceptible to shape loss due to its internal porosity. By contrast, Cu-graphite, Cu-ZrB2 and Cu-TiB2 composites show good capabilities of removing material with little wear loss and therefore could be promising for future usages.
20
Shu, Dayu, Xiuqing Li e Qingxia Yang. "Effect on Microstructure and Performance of B4C Content in B4C/Cu Composite". Metals 11, n. 8 (6 agosto 2021): 1250. http://dx.doi.org/10.3390/met11081250.
Testo completoAbstract (sommario):
In this paper, boron carbide (B4C) ceramics were added to a copper (Cu) base, to improve the mechanical properties and wear resistance of pure copper. The B4C/Cu composites with different B4C contents, were obtained by mechanical mixing and discharge plasma sintering methods. Scanning electron microscopy (SEM), energy spectrum analysis (EDS), and electron probe microanalysis (EPMA) were used, to observe and analyze the microstructures of the B4C/Cu composites. The influences of the B4C content on the hardness, density, conductivity, and wear resistance were also studied. The experimental results show that B4C has an important effect on Cu. With increasing B4C content, both the density and conductivity of the B4C/Cu composites gradually decrease. The hardness of the Cu-15 wt.% B4C composite has the highest value, 86 HBW (Brinell hardness tungsten carbide ball indenter), which is 79.2% higher than that of pure copper. However, when the B4C amount increases to 20 wt.%, the hardness decreases due to the metallic connection being weakened in the material. The Cu-15 wt.% B4C composite has the lowest volume loss, indicating that it has the best wear resistance. Analyses of worn B4C/Cu composite surfaces suggest that deep and narrow grooves, as well as sharp ridges, appear on the worn pure Cu surface, but on the worn Cu-15 wt.% B4C composite surface, the furrows become shallow and few. In particular, ridge formation cannot be found on the worn Cu-15 wt.% B4C composite surface, which represents the enhancement in wear resistance.
21
Li, Xiuqing, Minjie Zhang, Guoshang Zhang, Shizhong Wei, Qi Wang, Wenpeng Lou, Jingkun Liang et al. "Influence Evaluation of Tungsten Content on Microstructure and Properties of Cu-W Composite". Metals 12, n. 10 (5 ottobre 2022): 1668. http://dx.doi.org/10.3390/met12101668.
Testo completoAbstract (sommario):
At present, most studies focus on Cu-W composites with high W content (W content > 50 wt%), while there are only sporadic reports on Cu-W composites with low W content (W content < 50 wt%). In this work, Cu-W composites with different W contents (0, 10 wt%, 20 wt% and 30 wt%) were prepared, and the effects of W content on microstructure, density, hardness, electrical conductivity, strength and electrical contact properties were systematically studied, with the expectation of providing an experimental basis and theoretical support for expanding the application range of Cu-W composites with low W content. The results showed that, with the increase in W content, the Cu matrices divided into finer and more uniform grains; the density and electrical conductivity of Cu-W composites decreased; and the compressive yield strength and hardness gradually increased. As the content of W increased, the arc burning time of the Cu-W composite contacts began to fluctuate. There was a loss of both the cathode and the anode contacts of the pure Cu, but the mass transfer of the Cu-W composite contacts occurred as follows: the anode weight increases, while the cathode weight decreases. The addition of W particles changed the non-uniform ablation of the pure Cu, and the surface ablation of the Cu-W composite contacts remained uniform.
22
Cai, Hui, Debao Tong, Yaping Wang, Xiaoping Song e Bingjun Ding. "Novel Cu/Si composites: A sol-gel-derived Al2O3 film as barrier to control interfacial reaction". Journal of Materials Research 25, n. 11 (novembre 2010): 2238–44. http://dx.doi.org/10.1557/jmr.2010.0271.
Testo completoAbstract (sommario):
Cu/Si composite may be a novel and high-performance material for electronic packaging if the advantages of copper and silicon components are preserved. Because of the severe diffusional reaction between copper and silicon at elevated temperature, efforts are impeded to achieve a bulk Cu/Si composite. Here, by coating a sol-gel-derived Al2O3 film on the Si particle surface, the bulk Cu/Si composites were obtained by the powder metallurgy method. In the prepared Cu/Si composite, Cu forms a continuous matrix while Si particles are homogeneously dispersed in Cu matrix. High-resolution transmission electron microscopy observation indicates that only weak interfacial reaction occurs at the Cu/Al2O3/Si interface and forms a narrow interfacial reaction zone. The thermal diffusivity of the composite at 25 °C is about 30.6 mm2 s−1, over 10 times larger than that of Cu/Si material without Al2O3 film.
23
Zheng, Hang, Ruixiang Zhang, Qin Xu, Xiangqing Kong, Wanting Sun, Ying Fu, Muhong Wu e Kaihui Liu. "Fabrication of Cu/Al/Cu Laminated Composites Reinforced with Graphene by Hot Pressing and Evaluation of Their Electrical Conductivity". Materials 16, n. 2 (9 gennaio 2023): 622. http://dx.doi.org/10.3390/ma16020622.
Testo completoAbstract (sommario):
Metal laminated composites are widely used in industrial and commercial applications due to their excellent overall performance. In this study, the copper/graphene-aluminum-copper/graphene (Cu/Gr-Al-Cu/Gr) laminated composites were prepared by ingenious hot pressing design. Raman, optical microscope (OM), scanning electron microscope (SEM), van der Pauw (vdP), and X-Ray Diffractometer (XRD) were used to investigate the graphene status, interface bonding, diffusion layer thickness, electrical conductivity, Miller indices and secondary phases, respectively. The results demonstrate that the Cu-Al interfaces in the Cu/Gr-Al-Cu/Gr composites were free of pores, cracks and other defects and bonded well. The number of graphene layers was varied by regulating the thickness of the Cu/Gr layer, with the Cu/Gr foils fabricated by chemical vapor deposition (CVD). The electrical conductivity of the composite was significantly improved by the induced high-quality interfaces Cu/Gr structure. The increased number of graphene layers is beneficial for enhancing the electrical conductivity of the Cu/Gr-Al-Cu/Gr composite, and the highest conductivity improved by 20.5% compared to that of raw Al.
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Kim, Dasom, Kyungju Kim e Hansang Kwon. "Interdiffusion and Intermetallic Compounds at Al/Cu Interfaces in Al-50vol.%Cu Composite Prepared by Solid-State Sintering". Materials 14, n. 15 (31 luglio 2021): 4307. http://dx.doi.org/10.3390/ma14154307.
Testo completoAbstract (sommario):
Al–Cu composites have attracted significant interest recently owing to their lightweight nature and remarkable thermal properties. Understanding the interdiffusion mechanism at the numerous Al/Cu interfaces is crucial to obtain Al–Cu composites with high thermal conductivities. The present study systematically investigates the interdiffusion mechanism at Al/Cu interfaces in relation to the process temperature. Al-50vol.%Cu composite powder, where Cu particles were encapsulated in a matrix of irregular Al particles, was prepared and then sintered at various temperatures from 340 to 500 °C. Intermetallic compounds (ICs) such as CuAl2 and Cu9Al4 were formed at the Al/Cu interfaces during sintering. Microstructural analysis showed that the thickness of the interdiffusion layer, which comprised the CuAl2 and Cu9Al4 ICs, drastically increased above 400 °C. The Vickers hardness of the Al-50vol.%Cu composite sintered at 380 °C was 79 HV, which was 1.5 times that of the value estimated by the rule of mixtures. A high thermal conductivity of 150 W∙m−1∙K−1 was simultaneously obtained. This result suggests that the Al-50vol.%Cu composite material with large number of Al/Cu interfaces, as well as good mechanical strength and heat conductance, can be prepared by solid-state sintering at a low temperature.
25
Xie, Zhongnan, Hong Guo, Ximin Zhang e Shuhui Huang. "Corrosion Behavior of Pressure Infiltration Diamond/Cu Composites in Neutral Salt Spray". Materials 13, n. 8 (14 aprile 2020): 1847. http://dx.doi.org/10.3390/ma13081847.
Testo completoAbstract (sommario):
Diamond particle-reinforced copper matrix composites (Diamond/Cu) are recognized as promising electronic packaging materials due to their excellent thermophysical properties. It is necessary to investigate the reliability of Diamond/Cu composites under extreme environmental conditions. The corrosion behavior of Diamond/Cu composites was studied in a 5 wt% NaCl neutral salt spray. Surface morphology, thermal conductivity, bending strength, corrosion rate, and corrosion depth resulting from corrosion were researched in this paper. The results showed that the corrosion phenomenon mainly occurs on the copper matrix, and the diamond and interface products do not corrode. The corrosion mechanism of Diamond/Cu composites was micro-galvanic corrosion. The corrosion product formed was Cu2Cl(OH)3. The salt spray environment had a great influence on the composite surface, but the composite properties were not significantly degenerated. After a 168-h test, the bending strength was unaltered and the thermal conductivity of gold-plated composites showed a slight decrease of 1–2%. Surface gold plating can effectively improve the surface state and thermal conductivity of Diamond/Cu composites in a salt spray environment.
26
Kasach, Aliaksandr A., Dzmitry S. Kharytonau, Andrei V. Paspelau, Jacek Ryl, Denis S. Sergievich, Ivan M. Zharskii e Irina I. Kurilo. "Effect of TiO2 Concentration on Microstructure and Properties of Composite Cu–Sn–TiO2 Coatings Obtained by Electrodeposition". Materials 14, n. 20 (18 ottobre 2021): 6179. http://dx.doi.org/10.3390/ma14206179.
Testo completoAbstract (sommario):
In this work, Cu–Sn–TiO2 composite coatings were electrochemically obtained from a sulfate bath containing 0–10 g/L of TiO2 nanoparticles. The effect of TiO2 particles on kinetics of cathodic electrodeposition has been studied by linear sweep voltammetry and chronopotentiometry. As compared to the Cu–Sn alloy, the Cu–Sn–TiO2 composite coatings show rougher surfaces with TiO2 agglomerates embedded in the metal matrix. The highest average amount of included TiO2 is 1.7 wt.%, in the case of the bath containing 5 g/L thereof. Composite coatings showed significantly improved antibacterial properties towards E. coli ATCC 8739 bacteria as compared to the Cu–Sn coatings of the same composition. Such improvement has been connected with the corrosion resistance of the composites studied by linear polarization and electrochemical impedance spectroscopy. In the bacterial media and 3% NaCl solutions, Cu–Sn–TiO2 composite coatings have lower corrosion resistance as compared to Cu–Sn alloys, which is caused by the nonuniformity of the surface.
27
Kumar, Lailesh, Harshpreet Singh, Santosh Kumar Sahoo e Syed Nasimul Alam. "Effect of nanostructured Cu on microstructure, microhardness and wear behavior of Cu-xGnP composites developed using mechanical alloying". Journal of Composite Materials 55, n. 16 (14 gennaio 2021): 2237–48. http://dx.doi.org/10.1177/0021998320987887.
Testo completoAbstract (sommario):
In the present study, Cu-1, 2 and 3 wt.% xGnP composites have been developed by powder metallurgy (PM) route using nanostructured Cu powder and their effect on microstructure, microhardness, sliding wear behaviour has been examined. The crystallite size and lattice strain of Cu after 25 h of mechanical milling have been found to be 16 nm and 0.576%, respectively. Major challenges associated with the development of Cu-xGnP composites is the uniform dispersion of the nanoplatelets in the Cu matrix, which have been dealt out by incorporating the nanostructured Cu- xGnP composites after mechanical alloying leading to the homogenous distribution of nanoplatelets in the Cu-matrix. A significant enhancement in relative density, microhardness and wear resistance of the Cu-3 wt. % xGnP nanofiller composite in particular has been observed due to the uniform distribution of the nanofillers. In Cu-3 wt. % xGnP composite developed using as-milled nanostructured Cu, a microhardness of ∼ 1.1 GPa could be achieved which is about ∼3 times higher than that of the pure sintered Cu sample (∼359 MPa). Nanostructured Cu also leads to enhancement of the hardness and wear property as compared to the as-received Cu. The wear mechanism in the various nanostructured Cu-xGnP composites has been studied in details.
28
Pugacheva, N. B., T. M. Bykova e E. I. Senaeva. "Structure and micromechanical properties of SHS composites with a copper matrix: peculiarities of formation". Frontier materials & technologies, n. 4 (2023): 99–108. http://dx.doi.org/10.18323/2782-4039-2023-4-66-9.
Testo completoAbstract (sommario):
Self-propagating high-temperature synthesis (SHS) is one of the promising methods for producing strong and wear-resistant composites. The use of copper as a matrix due to the unique combination of electrical and thermal conductivity is of particular interest. Monolithic SHS composites of the Cu–Ti–C–B and Cu–Ti–C systems are currently little studied. The information on the phase composition of such composites is contradictory, and data on micromechanical properties is practically absent. The paper presents the results of a comparative analysis of the structure and micromechanical properties of composites of the Cu–Ti–C and Cu–Ti–C–B systems. It is found that the matrix of both composites is a copper-based solid solution supersaturated with titanium, in which nanosized Cu4Ti intermetallic compound particles precipitate upon cooling. TiC particles (Cu–Ti–C composite) and TiC and TiB2 particles (Cu–Ti–C–B composite) are the strengthening phases resulting from SHS. In the Cu–Ti–C–B composite, the original particles of unreacted B4C boron carbide were preserved, the microhardness of which was 3680 HV 0.1. The most ductile structural constituent in the Cu–Ti–B system composite is the Cu+Cu4Ti mechanical mixture, due to which further plastic deformation is possible to obtain parts of a given shape. During the study of micromechanical properties, the maximum strength indicators of HIT, HV, We, Re, HIT/E* were recorded in the Cu–Ti–C–B system composite, which allows expecting high wear resistance of products made of it.
29
Chmielewski, Marcin, Katarzyna Pietrzak, Dariusz Kaliński e Agata Strojny. "Processing and Thermal Properties of Cu-AlN Composites". Advances in Science and Technology 65 (ottobre 2010): 100–105. http://dx.doi.org/10.4028/www.scientific.net/ast.65.100.
Testo completoAbstract (sommario):
Heat transfer by conduction is involved in the use of heat sinks dissipitating heat from electronic devices. Effective transfer of heat requires using materials of high thermal conductivity. In addition, it requires appropriate values of thermal expansion, matched to the semiconductor materials, high purity of materials used and good contact between bonded elements across which heat transfer occurs. The conventional materials are not able to fulfil still raising and complex requirements. The solutions of this problem could be using the composites materials, where the combinations of different properties is possible to use. This study presents the technological tests and the analysis of correlation between processing parameters and the properties of copperaluminium nitride composites. Composite materials were obtained by mixing in planetary ball mill and then densified using the sintering under pressure or hot pressing method. The microstructure of obtained composite materials using optical microscopy and scanning electron microscopy were analyzed. Coefficient of thermal expansion (CTE) and thermal conductivity (TC) were investigated depending on the process conditions.
30
Guo, Jun Qing, He Yang, Ping Liu, Shu Guo Jia, Li Ming Bi e Hua Huang. "Rolling Processes and Performance of Cu-Fe In Situ Composites". Advanced Materials Research 79-82 (agosto 2009): 159–62. http://dx.doi.org/10.4028/www.scientific.net/amr.79-82.159.
Testo completoAbstract (sommario):
The deformation processed Cu-based in-situ composite was a kind of structural function materials with high physical and mechanical performance and used widely in large scale integrated circuit. Especially, the sheet material of Cu-Fe in-situ composites was interested to researchers because the Fe was cheaper and the use of sheets was more widely in electron industry. In this study, the sheets of Cu-10Fe-1Ag in-situ composite were achieved by cold rolling which the thickness was from 6mm to 2.56mm, 1.28mm, 0.64mm and 0.32mm. Corresponding, the rolling ratio was 4.9, 5.3, 5.9 and 6.6. The maximum strength was 722Mpa at the rolling ratio 4.9. The conductivity was measured also with maximum 59.5% IACS. The experimental results show that the tensile strength and electrical resistance increase with the increasing of rolling strain. Although the conductivity of Cu-Fe in-situ composites was not very high, the matching of strength and conductivity was favorable. It is feasible that the high performance Cu-based in-situ composite can be obtained by cold rolling with merits of materials cheaper, melting simple and usage wide
31
Tang, Ying, e Xian Ping Xia. "Improvement of the Hydrophilicity of Cu/LDPE Composite and its Influence on the Release of Cupric Ions". Materials Science Forum 745-746 (febbraio 2013): 46–52. http://dx.doi.org/10.4028/www.scientific.net/msf.745-746.46.
Testo completoAbstract (sommario):
t is of great importance to improve the hydrophilicity of Cu/LDPE composite, a material for a new type of IUDs (Intrauterine Devices). The aim of the study is not only satisfying the biocompatibility of medical devices implanted in human bodies, but also improving the releasing rate of cupric ions. In this study, various hydrophilic materials (sodium chloride, anhydrous glucose and soluble starch) were added respectively, in order to improve the hydrophilicity of Cu/LDPE composite. The microstructure of Cu/LDPE composite was characterized, moreover, the influence of the addition of these hydrophilic materials on the surface hydrophilicity and the releasing rate of cupric ions of Cu/LDPE composite was studied. The compatibility between three hydrophilic materials and the matrix of LDPE is rather different, which can affect the dispersible uniformity of these additives in Cu/LDPE composite, and the dispersible uniformity of NaCl is the worst among these three hydrophilic materials. The addition of three hydrophilic materials was all beneficial to the improvement of the hydrophilicity of Cu/LDPE composite. Connected holes were formed in Cu/LDPE composite, which provided channels for the infiltration of solution and the diffusion of cupric ions, and improved the releasing rate of cupric ions in the Cu/LDPE composite IUDs.
32
El-khatib, Samah, A. H. Elsayed, A. Y. Shash e A. El-Habak. "Effect of Dispersions of Al2O3 on the Physical and Mechanical Properties of Pur ties of Pure Copper and Copper-Nick e Copper and Copper-Nickel Allo el Alloy". Future Engineering Journal 3, n. 1 (29 giugno 2022): 10–19. http://dx.doi.org/10.54623/fue.fej.3.1.2.
Testo completoAbstract (sommario):
This paper illustrates the mechanical and physical properties of pure Cu and Cu-Ni (50-50 wt. %) alloy mixed with Al2O3 (1-4 wt. %) as micro-particles reinforcement materials. The attained composite alloy specimens' characteristics were estimated such as microstructure, relative density, electrical and thermal conductivity, hardness, and compression yield stress properties to adjust the suitable optimum percentage of reinforcing material which has the best physical and mechanical properties with different main matrix materials whether pure Cu powder or Cu-Ni mechanical alloy. The micron-sized Al2O3 was added to enhance the mechanical and physical properties of the pure Cu and Cu-Ni alloy composites. The electrical and thermal conductivity for pure Cu alloy composites were improved compared to the copper-nickel alloy matrix composites material. The hardness and compression yield stress of pure copper has enhancement values and for Cu-Ni alloy composites have enhancement values and for Cu-Ni base composites, hardness and compression yield stress have improved with the most positive enhancement values.
33
Yunlong, Zhang, Li Wenbo, Hu Ming, Yi Hongyong, Zhou Wei, Ding Peiling e Tang Lili. "Fabrication of SiC@Cu/Cu Composites with the Addition of SiC@Cu Powder by Magnetron Sputtering". International Journal of Photoenergy 2021 (25 febbraio 2021): 1–8. http://dx.doi.org/10.1155/2021/6623776.
Testo completoAbstract (sommario):
In view of the surface engineering application of electrical contact materials, SiC ceramic particles were introduced into copper matrix composites by the hot-press sintering method for the sake of enhancing the service life of copper matrix electrical contact materials. Magnetron sputtering technology was exploited to form the continuous copper film on the β-SiC powders in order to improve interface wettability between SiC powder and copper matrix. The SiC@Cu powders were treated by magnetron sputtering technology. Then, dynamic deposit behavior was described according to SEM results. The phase constitution, fracture morphology, relative density, porosity, Vickers hardness, and coefficient of thermal expansion of SiC@Cu/Cu composites with different SiC@Cu addition were analyzed in detail. The results showed that SiC@Cu powders with higher fraction in the SiC@Cu/Cu composites would decrease relative density and increase porosity, so it resulted in improvement of Vickers hardness. The addition of SiC@Cu decreased CTE values of the SiC@Cu/Cu composite, especially at high-level fraction SiC@Cu powder.
34
Liu, Baoliang, Wenxin Wei e Changqing Li. "Preparation and Properties of Cu-Plated Graphene/Cu Composites". Science of Advanced Materials 16, n. 4 (1 aprile 2024): 459–67. http://dx.doi.org/10.1166/sam.2024.4663.
Testo completoAbstract (sommario):
This research delves into the realm of advanced composite materials, focusing on the preparation and mechanical properties of Cu-plated graphene (Cu@rGO) and its comparison with copper-plated graphite (Cu@G). The electroless plating method was employed to create Cu@rGO and Cu@G, which were subsequently mixed with copper powder and pressed, leading to the formation of Cu@rGO/Cu and Cu@G/Cu composites through vacuum sintering. A meticulous analysis of the mechanical properties, specifically hardness and compression strength, was conducted. Our findings reveal intriguing trends in the mechanical behavior of these composites. In Cu@rGO/Cu sintered bodies, the hardness and compressive strength exhibit an increase with rising Cu@rGO content, up to 1.2 wt.%. Conversely, under analogous conditions, Cu@G/Cu sintered bodies display a decrease in both hardness and compressive strength as the Cu@G content rises. This research not only contributes valuable insights into the preparation techniques of these composites but also sheds light on the nuanced mechanical responses associated with varying reinforcement phases. The implications of these findings extend to diverse engineering applications, paving the way for optimized designs and applications of graphene-enhanced copper composites.
35
Lei, Lei, Leandro Bolzoni e Fei Yang. "The Impact of Interface Characteristics on Mechanical Performance of a Hot-Forged Cu/Ti-Coated-Diamond Composite". Materials Science Forum 1016 (gennaio 2021): 1682–89. http://dx.doi.org/10.4028/www.scientific.net/msf.1016.1682.
Testo completoAbstract (sommario):
The Cu/55vol.%diamond (Ti) composites were fabricated by hot forging of the cold-pressed powder preforms, consisted of elemental copper powders and Ti-coated diamond particles, at 800 °C (800C-Cu/55Dia composite) and 1050 °C (1050C-Cu55Dia composite), respectively. Well bonded interface was achieved between the diamond and the copper matrix for the 800C-Cu/55Dia composite, and the coverage of diamond by interface was about 96%, attributed to homogeneously distributed nanospherical TiC interface formed on the diamond surface. However, obvious coarse TiC particle size and spallation of the formed interface were observed in the 1050C-Cu55Dia composite, implying that the composite had a relatively low bonding strength. The formed chemical bonding, good wettability and strong mechanical interlocking between the diamond and the copper matrix enable the 800C-Cu/55Dia composite having a high tensile strength of 145 MPa and a strain at fracture of 0.35%, which are about 260% and 170% higher than those of the 1050C-Cu55Dia composite, suggesting that the 800C-Cu/55Dia composite has the potential to have a high thermal conductivity and use as high-performance heat sink materials.
36
Stalin, B., M. Ravichandran, Alagar Karthick, M. Meignanamoorthy, G. T. Sudha, S. Karunakaran e Murugesan Bharani. "Investigations on Microstructure, Mechanical, Thermal, and Tribological Behavior of Cu-MWCNT Composites Processed by Powder Metallurgy". Journal of Nanomaterials 2021 (25 agosto 2021): 1–15. http://dx.doi.org/10.1155/2021/3913601.
Testo completoAbstract (sommario):
Copper (Cu) metal matrix composite (MMC) was developed with multiwall carbon nanotubes (MWCNT) as reinforcement by using powder metallurgy (PM) technique. The composition of the composites is Cu, Cu-4 wt% MWCNT, Cu-8 wt% MWCNT, and Cu-12 wt% MWCNT. The Cu and MWCNTs were blended for 6 hours in a ball mill and compacted at a 6 ton pressure to form green compacts using a 10 ton hydraulic press. Using a tubular furnace, the heat was applied at 900°C for 1.5 hours to impart strength and integrity to the green compacts. Milled composite blends were studied to analyze its characterization through SEM and EDAX analysis. Characterization studies such as SEM and EDAX confirm the presence and even dispersion of Cu and MWCNT constituents. The relative density, hardness, and ultimate compressive strength have been studied, and a remarkable improvement in properties has been obtained by the inclusion of MWCNTs. The composites reinforced by 8 and 12 wt% MWCNT were recorded with low thermal conductivity than the Cu composite reinforced by 4 wt% MWCNT. A wear study was analyzed using Taguchi technique for determining the effect caused by the wear test parameters and MWCNT content on wear rate. The optimized parameter that contributes minimum wear rate was identified as 12 wt% MWCNT content, 10 N applied load, 2 m/s sliding velocity, and 500 m sliding distance. Based on the obtained results, it could be understood that the produced composites can be utilized for various applications like relay contact springs and switchgear, rotor bars, and bus bars.
37
Chen, Cunguang, Qianyue Cui, Chengwei Yu, Pei Li, Weihao Han e Junjie Hao. "Effects of Zr-Cu Alloy Powder on Microstructure and Properties of Cu Matrix Composite with Highly-Aligned Flake Graphite". Materials 13, n. 24 (14 dicembre 2020): 5709. http://dx.doi.org/10.3390/ma13245709.
Testo completoAbstract (sommario):
Highly-aligned flake graphite (FG) reinforced Cu matrix composites with high thermal conductivity and adaptive coefficient of thermal expansion were successfully prepared via the collaborative process of tape-casting and hot-pressing sintering. To overcome the problem of fragile interface, Zr-Cu alloy powder was introduced instead of pure Zr powder to enhance the interfacial strength, ascribed to the physical-chemical bonding at the Cu-FG interface. The results indicate that the synthetic ZrC as interfacial phase affects the properties of FG/Cu composites. The thermal conductivity reaches the maximum value of 608.7 W/m∙K (52% higher than pure Cu) with 0.5 wt % Zr. Surprisingly, the negative coefficient of thermal expansion (CTE) in the Z direction is acquired from −7.61 × 10−6 to −1.1 × 10−6/K with 0 to 2 wt % Zr due to the physical mechanism of strain-engineering of the thermal expansion. Moreover, the CTE in X-Y plane with Zr addition is 8~10 × 10−6/K, meeting the requirements of semiconductor materials. Furthermore, the bending strength of the FG/Cu-2 wt % Zr composite is 42% higher than the FG/Cu composite. Combining excellent thermal conductivity with ultralow thermal expansion make the FG/Cu-Zr composites be a highly promising candidate in the electronic packaging field.
38
Zheng, Zhong, Anxin Yang, Jiafeng Tao, Jing Li, Wenqian Zhang, Xiuhong Li e Huan Xue. "Mechanical and Conductive Properties of Cu Matrix Composites Reinforced by Oriented Carbon Nanotubes with Different Coatings". Nanomaterials 12, n. 2 (14 gennaio 2022): 266. http://dx.doi.org/10.3390/nano12020266.
Testo completoAbstract (sommario):
Because of the dilemma that the current industrial Cu enhancement methods lead to a significant decline in conductivity and ductility, Cu matrix composites reinforced by oriented multi-walled carbon nanotubes (MWCNTs) were prepared through sintering, hot extrusion, and cold drawing. Before sintering, Ni, Cu, and Ni&Cu coatings were electroless plated on MWCNTs as the intermediate transition layer, and then they were mixed with Cu powder through a nitrogen bubbling assisted ultrasonic process. By analyzing the composition, microstructure, and formation mechanism of the interface between MWCNTs and the matrix, the influence and mechanism of the interface on the mechanical properties, conductivity, and ductility of the composites were explored. The results indicated that MWCNTs maintained a highly dispersed and highly consistent orientation in the Cu matrix. The coating on Ni@CNT was the densest, continuous, and complete. The Ni@CNTs/Cu composite had the greatest effect, while the Cu composite reinforced by MWCNT without coating had the smallest reduction in elongation and conductivity. The comprehensive performance of the Cu@CNTs/Cu composite was the most balanced, with an ultimate tensile strength that reached 373 MPa, while the ductility and conductivity were not excessively reduced. The axial electrical and thermal conductivity were 79.9 IACS % (International Annealed Copper Standard) and 376 W/mK, respectively.
39
Burtscher, Michael, Mingyue Zhao, Johann Kappacher, Alexander Leitner, Michael Wurmshuber, Manuel Pfeifenberger, Verena Maier-Kiener e Daniel Kiener. "High-Temperature Nanoindentation of an Advanced Nano-Crystalline W/Cu Composite". Nanomaterials 11, n. 11 (3 novembre 2021): 2951. http://dx.doi.org/10.3390/nano11112951.
Testo completoAbstract (sommario):
The applicability of nano-crystalline W/Cu composites is governed by their mechanical properties and microstructural stability at high temperatures. Therefore, mechanical and structural investigations of a high-pressure torsion deformed W/Cu nanocomposite were performed up to a temperature of 600 °C. Furthermore, the material was annealed at several temperatures for 1 h within a high-vacuum furnace to determine microstructural changes and surface effects. No significant increase of grain size, but distinct evaporation of the Cu phase accompanied by Cu pool and faceted Cu particle formation could be identified on the specimen′s surface. Additionally, high-temperature nanoindentation and strain rate jump tests were performed to investigate the materials mechanical response at elevated temperatures. Hardness and Young′s modulus decrease were noteworthy due to temperature-induced effects and slight grain growth. The strain rate sensitivity in dependent of the temperature remained constant for the investigated W/Cu composite material. Also, the activation volume of the nano-crystalline composite increased with temperature and behaved similar to coarse-grained W. The current study extends the understanding of the high-temperature behavior of nano-crystalline W/Cu composites within vacuum environments such as future fusion reactors.
40
Li, Xue, Ateeq Ahmed e Byung-Sang Choi. "Electrochemical Corrosion Resistance and Electrical Conductivity of Three-Dimensionally Interconnected Graphene-Reinforced Cu Composites". Korean Journal of Metals and Materials 59, n. 11 (5 novembre 2021): 821–28. http://dx.doi.org/10.3365/kjmm.2021.59.11.821.
Testo completoAbstract (sommario):
A three-dimensionally interconnected graphene-reinforced Cu (3Di Gr-Cu) composite was synthesized using a simple two-step process technique which involves the mechanical compaction of micronsized Cu particles followed by chemical vapor deposition (CVD) at 995 ℃. The microstructural properties of pure Cu and the 3Di Gr-Cu composite were investigated by optical microscope, scanning electron microscope, and X-ray diffractometer. The electrical and corrosion behaviors of the 3Di Gr-Cu composite and Cu only, prepared by powder metallurgy (PM Cu), were studied and compared. The electrical conductivity (EC) of the 3Di Gr-Cu composites was found to be 38.8 MSm<sup>−1</sup> at a carbon content of 73 ppm, and exhibited a 12% higher EC than the PM Cu. Due to the interconnected graphene around the Cu grains, the corrosion current density and corrosion rate of the 3Di Gr-Cu composite decreased by 29% and 40%, respectively, compared to the PM Cu. The EC of the 3Di Gr-Cu composite depended on the carbon content. The improvement in the EC of the 3Di Gr-Cu composite is attributed to the electron-carrying ability of the three-dimensionally interconnected graphene network (3DIGN) formed at the grain boundaries in the composite. The enhancement in corrosion resistance is due to the impermeability of graphene to various chemical species.
41
Cao, Haiyao, Zaiji Zhan e Xiangzhe Lv. "Microstructure Evolution and Properties of an In-Situ Nano-Gd2O3/Cu Composite by Powder Metallurgy". Materials 14, n. 17 (2 settembre 2021): 5021. http://dx.doi.org/10.3390/ma14175021.
Testo completoAbstract (sommario):
Gadolinia (Gd2O3) is potentially attractive as a dispersive phase for copper matrix composites due to its excellent thermodynamic stability. In this paper, a series of 1.5 vol% nano-Gd2O3/Cu composites were prepared via an internal oxidation method followed by powder metallurgy in the temperature range of 1123–1223 K with a holding time of 5–60 min. The effects of processing parameters on the microstructure and properties of the composites were analyzed. The results showed that the tensile strength and conductivity of the nano-Gd2O3/Cu composite have a strong link with the microporosity and grain size, while the microstructure of the composite was determined by the sintering temperature and holding time. The optimal sintering temperature and holding time for the composite were 1173 K and 30 min, respectively, under which a maximum ultimate tensile strength of 317 MPa was obtained, and the conductivity was 96.8% IACS. Transmission electron microscopy observations indicated that nano-Gd2O3 particles with a mean size of 76 nm formed a semi-coherent interface with the copper matrix. In the nano-Gd2O3/Cu composite, grain-boundary strengthening, Orowan strengthening, thermal mismatch strengthening, and load transfer strengthening mechanisms occurred simultaneously.
42
Zhu, Jianhua, Lei Liu, Guohua Hu, Bin Shen, Wenbin Hu e Wenjiang Ding. "Study on composite electroforming of Cu/SiCp composites". Materials Letters 58, n. 10 (aprile 2004): 1634–37. http://dx.doi.org/10.1016/j.matlet.2003.08.040.
Testo completo
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Hu, Ming, Jing Gao e Yun Long Zhang. "The Research of Spraying SiC/Cu Electronic Packaging Composites". Advanced Materials Research 284-286 (luglio 2011): 620–23. http://dx.doi.org/10.4028/www.scientific.net/amr.284-286.620.
Testo completoAbstract (sommario):
The SiC/Cu electronic packaging composites with excellent performance were successfully prepared by the chemical plating copper on the surface of SiC powders and high-speed flame spraying technology. The results showed that the homogeneous dense coated layers can be obtained on the surface of SiC powder by optimizing process parameters. The volume fraction of SiC powders in the composites could significantly increase and figure was beyond 55vol% after spraying Copper. The SiC and Cu were the main phases in the spraying SiC/Cu electronic packaging composite, at the same time Cu2O can be tested as the trace phase. The interface combination properties of SiC/Cu in the hot-pressed samples can obviously improve. The thermal expansion coefficient and thermal conductivity of SiC/Cu electronic packaging composite basic can satisfy the requirements for electronic packaging materials.
44
Wang, Haoran, Shuo Zhao, Junqing Han, Yuying Wu, Xiangfa Liu e Zuoshan Wei. "Neutron-Absorption Properties of B/Cu Composites". Materials 16, n. 4 (8 febbraio 2023): 1443. http://dx.doi.org/10.3390/ma16041443.
Testo completoAbstract (sommario):
Copper has high electrical and thermal conductivity, which is frequently employed in structural and functional materials. In this research, powder metallurgy was used to incorporate boron nanosheets into metal matrix composites to create boron dispersion-enhanced copper matrix composites. The neutron-absorption characteristics of composite materials were investigated, as well as the link between neutron-absorption cross-section and neutron energy. The results told us that the morphology of the second phase on the particle surface is closely related to the size of Cu-B particles, copper and boron correspond atomically to each other on the interface without dislocation or lattice distortion, forming a completely coherent interface, and that the neutron absorption cross-section decreases exponentially as neutron energy increases. In low-energy neutrons with energies less than 0.1 eV, the increase of boron content and 10B abundance in Cu-B alloy will enhance the neutron-absorption capacity of the alloy. Boron dispersion-strengthened copper matrix composites have good neutron-absorption capacity, and the microstructure and size of boron do not affect the neutron-absorption performance of composites with the same content of boron. The hardness of the B-dispersion-strengthened Cu matrix composite obtained by nanoindentation test is about 3.04 GPa. Copper matrix composites with boron dispersion reinforcement exhibit high hardness and neutron-absorption characteristics.
45
Gevorkyan, E. "Peculiarities of obtaining diamond-(Fe-Cu-Ni-Sn) composite materials by hot pressing". Functional materials 23, n. 4 (24 marzo 2017): 031–45. http://dx.doi.org/10.15407/fm24.01.031.
Testo completo
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Tian, Qing, Junhui Li, Xiao Huiwei e Can Zhou. "SiO2-coated Cu nanoparticle/epoxy resin composite and its application in the chip packaging field". High Performance Polymers 31, n. 4 (25 giugno 2018): 417–24. http://dx.doi.org/10.1177/0954008318781697.
Testo completoAbstract (sommario):
A silicon dioxide–copper (SiO2-Cu) epoxy resin composite material for chip packaging was made by a mechanical mixing method with epoxy resin as the base glue and SiO2 coated with nano-Cu (SiO2-Cu) particles as the filler. The dispersion of SiO2-Cu nanoparticles in epoxy resin was studied using scanning electron microscopy and transmission electron microscopy. Meanwhile, the effects of the filler on the coefficient of thermal conductivity, the coefficient of thermal expansion (CTE), and the mechanical properties of the composite material were also studied. The results show that SiO2-Cu nanoparticles disperse well in the epoxy resin, the coefficient of thermal conductivity of SiO2-Cu epoxy resin composites increases with an increase in the SiO2-Cu filler amount, the coefficient of thermal conductivity begins to decline when the filling volume is over 25%, and the suitable amount of SiO2-Cu is 25% of the total volume. With the increase in the filler, the CTE of the composite decreases; when the SiO2-Cu filling amount is 25%, the material has good impact resistance and a long electromigration failure time for chip packaging materials.
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Lin, Ting An, Jia-Horng Lin, Ting Ru Lin, Jan-Yi Lin, Mei-Chen Lin e Ching-Wen Lou. "Manufacturing techniques and property evaluations of sandwich-structured composite materials with electromagnetic shielding, flame retardance, and far-infrared emissivity". Journal of Sandwich Structures & Materials 22, n. 6 (15 agosto 2018): 2075–88. http://dx.doi.org/10.1177/1099636218789603.
Testo completoAbstract (sommario):
This study aims to produce sandwich-structured composite boards with flame retardance, far-infrared emissivity, and electromagnetic shielding effectiveness using nonwoven, weaving processes, and heat treatment. Needle punching and roller-type hot pressing are used to improve their tensile strength, tensile elongation, puncture strength, and burst strength. The limiting oxygen index is 30 regardless of whether the flame retardance/far-infrared emissivity/electromagnetic shielding effectiveness composite board is stainless steel (SS), SS+Ni–Cu (nickel-coated copper), or SS+Ni–Cu+Cu (copper) composite fabrics. SS+Ni–Cu and SS+Ni–Cu+Cu composite boards both have optimal thermal conductivity at the eighth test hour. SS–B composite board exhibit far-infrared emissivity of 0.81; moreover, they have optimal electromagnetic shielding effectiveness of −41dB at 2450 MHz when they are laminated into three layers at a 90° lamination.
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Likhatskyi, R. F., e Ye O. Matviets. "The structure of castings of cast composites of the Cu-V system obtained by electron beam casting". Metaloznavstvo ta obrobka metalìv 29, n. 3 (30 settembre 2023): 56–67. http://dx.doi.org/10.15407/mom2023.03.056.
Testo completoAbstract (sommario):
Keywords: Cu-V alloys, new electrotechnical materials, electron beam casting technology, as-cast composite materials, microstructure. Keywords: Cu-V alloys, new electrotechnical materials, electron beam casting technology, as-cast composite materials, microstructure.
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Rahman, Mostafizur, e Sadnan Mohosin Mondol. "Mechanical Behaviors of Al-Based Metal Composites Fabricated by Stir Casting Technique". Journal of Engineering Advancements 01, n. 04 (dicembre 2020): 144–49. http://dx.doi.org/10.38032/jea.2020.04.006.
Testo completoAbstract (sommario):
Recently, the demands of composite materials used in various engineering applications are growing higher because of their outstanding mechanical and thermal properties. This study represents an experimental investigation to determine mechanical properties of Al-based composites materials using Cu and SiC as reinforcement. Al-30-wt%-Cu, Al-40-wt%-Cu, Al-30-wt%-SiC, and Al-40-wt%-SiC composite bars were fabricated using stir casting process to ensure uniform distribution of reinforced elements. The composite bars were prepared into required shape to conduct test for evaluating mechanical properties. Al-40-wt%-Cu shows improved properties such as, hardness, strength, and impact energy absorption than Al-30-wt%-Cu due to more presence of Cu content. Al-30-wt%-Cu and Al-40-wt%-Cu bars showed improved mechanical properties than both Al-30-wt%-SiC and Al-40-wt%-SiC. It is also seen that Al-30-wt%-Cu and Al-40-wt%-Cu showed high hardness, yield strength, and impact energy absorption compared to Al-30-wt%-SiC and Al-40-wt%-Cu respectively. On the other hand, Al-30-wt%-Cu is 3.5% lightweight than Al-30-wt%-SiC and Al-40-wt%-Cu is 2.11% lightweight than Al-40-wt%-SiC. Al-30-wt%-Cu and Al-40-wt%-Cu showed improved specific hardness, specific yield strength, and specific impact energy absorption compared to Al-30-wt%-SiC and Al-40-wt%-Cu respectively. In addition, Al-40-wt%-Cu showed better mechanical properties among the bars.
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Priyadarsini, M. H., M. C. Adhikary, P. Jena e R. M. Pujahari. "Copper Doped PPy/MWCNT Nanocomposite Materials for Supercapacitor Applications". Journal of Scientific Research 15, n. 1 (1 gennaio 2023): 43–53. http://dx.doi.org/10.3329/jsr.v15i1.59397.
Testo completoAbstract (sommario):
We report the structural, morphological, and electrochemical properties of polypyrrole (PPy), copper doped PPy (Cu/PPy), and copper doped polypyrrole multi-walled carbon nanotubes (Cu/PPy/MWCTs) prepared by oxidative polymerization technique. The incorporation of Cu in the form of nanoparticles in the composites was confirmed from XRD data. The granular morphology of PPy was observed from the FESEM micrograph. However, the size of the grains was decreased with Cu nanoparticle insertion in the matrix. The uniform distribution of Cu nanoparticles in the Cu/PPy and Cu/PPy/MWCTs nanocomposites has been evidenced from TEM images. The highest specific capacitance of 311 F/g at a scan rate of 10 mV/s is achieved in the case of Cu/PPy/MWCTs composite. It is found that the cyclic stability of these nanocomposites is enhanced due to the integration of MWCNTS and Cu nanoparticles with PPy polymer. The Cu/PPy/MWCNTs nanocomposites retained 91% of their specific capacitance even after 1000 cycles. The maximum energy density of 19.89 Wh/kg and maximum power density of 4479.71 W/kg at the scan rate of 200 mV/s were also measured for the Cu/PPy/MWCNTs nanocomposite. Our study thus indicates that the prepared Cu/PPy/MWCTs nanocomposite could be a potential candidate for application in supercapacitor and hybrid type storing devices.