Properties and Fabrication of Alumina Dispersion Strengthened Copper Alloy with High Softening Temperature

2013 ◽  
Vol 749 ◽  
pp. 425-431 ◽  
Author(s):  
Sheng Li Han ◽  
Xiao Dong Qin ◽  
Yi Xiang Cai ◽  
Kai Luo ◽  
Huan Wen Xie ◽  
...  

Cu-Al2O3 alloy combine both high electronic conductivity and high softening temperature. Cu-Al2O3 alloy was fabricated by internal oxidation and hot extrusion methods in the present investigation. Microstructure and properties of Cu-Al2O3 alloy was studied. The influence of preparation parameters, hot extrusion parameters and heat treatment on the properties of the alloy was investigated. The results indicated that the grain of the alloy was very small with a size between 2-10μm. Softening temperature of the Cu-0.6% Al2O3 alloy and Cu-1.0% Al2O3 alloy was 900. Cu-0.6%Al2O3 alloy and Cu-1.0% Al2O3 alloy meeting the requirements for electrode in resistance welding is the ideal substitution of the traditional electrode materials for resistance welding.

2006 ◽  
Vol 510-511 ◽  
pp. 322-325
Author(s):  
Hoon Cho ◽  
Han Shin Choi ◽  
Hyung Ho Jo

The environmentally friendly manufacturing process, continuous casting process with small cross sections, is the near net-shaped manufacturing technology used to fabricate copper alloy wires and plates with the required final tolerance and sound quality. Furthermore, the process consumes less energy and discharges less environmental loads because the process can eliminate the need for hot extrusion, hot rolling and heat treatment for production copper alloy wires and plate. In the present study, the effects of a continuous casting speed on the mechanical properties and the microstructure of the nickel-silver (Cu-Ni-Zn) alloy were studied and energy requirements, atmospheric CO2 emission and yield for the production of the Cu-Ni-Zn alloy was investigated quantitatively with respect to continuous casting with small cross sections and conventional material processing including casting, extrusion and heat treatment. The yield for production of Cu-Ni-Zn alloy can be improved above 30% with the application of continuous casting with small cross sections when the productivity is similar. Twice the amount of energy required and CO2 were consumed and emitted in the conventional manufacturing process when the yield of the processes was considered.


1982 ◽  
Vol 20 ◽  
Author(s):  
Serge Flandrois ◽  
Francis Baron

ABSTRACTGraphite intercalation compounds can be used as electrode materials in batteries owing to the high electronic conductivity of carbon layers and the easy diffusion of ions between the layers. Moreover intercalation has the beneficial effect of impeding some parasitic reactions detrimental to good electrode reversibility. After a brief review of recent proposals, emphasis is given to transition metal chlorides. It is shown that, besides the nickel chloride-graphite compound proposed two years ago as a cathode material for alkaline batteries, other metal chlorides intercalated into graphite are excellent cathode or anode materials.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Su Hyun Yang ◽  
Yun Jae Lee ◽  
Heemin Kang ◽  
Seung-Keun Park ◽  
Yun Chan Kang

AbstractTwo-dimensional (2D) MXenes are promising as electrode materials for energy storage, owing to their high electronic conductivity and low diffusion barrier. Unfortunately, similar to most 2D materials, MXene nanosheets easily restack during the electrode preparation, which degrades the electrochemical performance of MXene-based materials. A novel synthetic strategy is proposed for converting MXene into restacking-inhibited three-dimensional (3D) balls coated with iron selenides and carbon. This strategy involves the preparation of Fe2O3@carbon/MXene microspheres via a facile ultrasonic spray pyrolysis and subsequent selenization process. Such 3D structuring effectively prevents interlayer restacking, increases the surface area, and accelerates ion transport, while maintaining the attractive properties of MXene. Furthermore, combining iron selenides and carbon with 3D MXene balls offers many more sites for ion storage and enhances the structural robustness of the composite balls. The resultant 3D structured microspheres exhibit a high reversible capacity of 410 mAh g−1 after 200 cycles at 0.1 A g−1 in potassium-ion batteries, corresponding to the capacity retention of 97% as calculated based on 100 cycles. Even at a high current density of 5.0 A g−1, the composite exhibits a discharge capacity of 169 mAh g−1.


Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2908
Author(s):  
Sul Ki Park ◽  
Jagadeesh Sure ◽  
D. Sri Maha Vishnu ◽  
Seong Jun Jo ◽  
Woo Cheol Lee ◽  
...  

Carbon nanotubes (CNTs) are being increasingly studied as electrode materials for supercapacitors (SCs) due to their high electronic conductivity and chemical and mechanical stability. However, their energy density and specific capacitance have not reached the commercial stage due to their electrostatic charge storage system via a non-faradic mechanism. Moreover, magnetite (Fe3O4) exhibits higher specific capacitance originating from its pseudocapacitive behaviour, while it has irreversible volume expansion during cycling. Therefore, a very interesting and facile strategy to arrive at better performance and stability is to integrate CNTs and Fe3O4. In this study, we demonstrate the microwave-solvothermal process for the synthesis of Fe3O4 nanoparticles uniformly grown on a CNT composite as an electrode for SCs. The synthesized Fe3O4/CNT composite delivers a reversible capacitance of 187.1 F/g at 1 A/g, superior rate capability by maintaining 61.6% of 10 A/g (vs. 1 A/g), and cycling stability of 80.2% after 1000 cycles at 1 A/g.


Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2394
Author(s):  
Lubov S. Skutina ◽  
Aleksey A. Vylkov ◽  
Dmitry K. Kuznetsov ◽  
Dmitry A. Medvedev ◽  
Vladimir Ya. Shur

The design of new electrode materials for solid oxide electrochemical cells, which are stable against redox processes as well as exhibiting carbon/sulphur tolerance and high electronic conductivity, is a matter of considerable current interest as a means of overcoming the disadvantages of traditional Ni-containing cermets. In the present work, composite materials having the general formula (1−x)Sr2Mg0.25Ni0.75MoO6−δ + xNiO (where x = 0, 15, 30, 50, 70 and 85 mol.%) were successfully prepared to be utilised in solid oxide fuel cells. A detailed investigation of the thermal, electrical, and microstructural properties of these composites, along with their phase stability in oxidising and reducing atmospheres, was carried out. While possessing low thermal expansion coefficient (TEC) values, the composites having low Ni content (15 mol.%–70 mol.%) did not satisfy the requirement of high electronic conductivity. Conversely, the 15Sr2Mg0.25Ni0.75MoO6−δ + 85NiO samples demonstrated very high electrical conductivity (489 S sm−1 at 850 °C in wet H2) due to well-developed Ni-based networks, and no deterioration of thermal properties (TEC values of 15.4 × 10−6 K−1 in air and 14.5 × 10−6 K−1 in 50%H2/Ar; linear expansion behaviour in both atmospheres). Therefore, this material has potential for use as a component of a fuel cell electrode system.


2020 ◽  
Vol 16 (1) ◽  
pp. 79-85 ◽  
Author(s):  
Palani Anandhi ◽  
Veerabadran Jawahar Senthil Kumar ◽  
Santhanam Harikrishnan

Background: Of late, supercapacitors have been drawing great attention over other rechargeable energy storage devices. More efforts are made on the electrode materials of the supercapacitors, in order to improve the specific capacitance and energy density. Based on the past literature, it was stated that pure TiO2 (as electrode material) could promote faradaic reaction to a limited extent due to its low electronic conductivity. Further, this low conductivity could hinder the ion transfer process between electrolyte and electrode during intercalation and de-intercalation, resulting in poor energy density. Hence, it is essential to incorporate high electronic conductivity material into TiO2, for improving the electrochemical performance. Objective: In the present study, the preparation and electrochemical performance of NiO/TiO2 nanocomposites as an electrode material for supercapacitor were extensively studied. Methods: NiO/TiO2 nanocomposites were synthesized by sol-gel method. The as-prepared nanocomposites were characterized by high-resolution TEM, field emission SEM and XRD. The electrochemical behaviors of the electrode using nanocomposites were assessed by means of cyclic voltammetry (CV) and galvanostatic charge-discharge tests. Results: The maximum specific capacitance of the nanocomposites based electrode witnessed through CV test was 405 F g-1 at the scan rate of 5 mV s-1 in 1M Na2SO4 electrolyte. The capacitance retention after 5000 charge-discharge cycles was estimated as 92.32%. The energy and power densities at current density of 1 A g-1 were found to be 5.67 Wh kg-1 and 210.52 W kg-1, respectively. Conclusion: NiO/TiO2 nanocomposites synthesized via sol-gel technique appeared to be flake-like structure. NiO incorporated into TiO2 increased higher electronic conductivity while comparing to pure TiO2. Also, an introduction of NiO into TiO2 improved the specific capacitance, power density, energy density and cycle stability. Due to these facts, combining NiO with TiO2 could be considered to be an efficient way of enhancing the electrochemical performance of electrodes of the supercapacitor.


Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 604 ◽  
Author(s):  
Wenyue Li ◽  
Nazifah Islam ◽  
Guofeng Ren ◽  
Shiqi Li ◽  
Zhaoyang Fan

There is strong interest in developing high-frequency (HF) supercapacitors or electrochemical capacitors (ECs), which can work at the hundreds to kilo hertz range for line-frequency alternating current (AC) filtering in the substitution of bulky aluminum electrolytic capacitors, with broad applications in the power and electronic fields. Although great progress has been achieved in the studies of electrode materials for ECs, most of them are not suitable to work in this high frequency range because of the slow electrochemical processes involved. Edge-oriented vertical graphene (VG) networks on 3D scaffolds have a unique structure that offers straightforward pore configuration, reasonable surface area, and high electronic conductivity, thus allowing the fabrication of HF-ECs. Comparatively, highly conductive freestanding cross-linked carbon nanofibers (CCNFs), derived from bacterial cellulose in a rapid plasma pyrolysis process, can also provide a large surface area but free of rate-limiting micropores, and are another good candidate for HF-ECs. In this mini review, advances in these fields are summarized, with emphasis on our recent contributions in the study of these materials and their electrochemical properties including preliminary demonstrations of HF-ECs for AC line filtering and pulse power storage applications.


2011 ◽  
Vol 694 ◽  
pp. 508-512 ◽  
Author(s):  
Wei Ling Guo ◽  
En Zhong Li ◽  
Da Xiang Yang ◽  
Hao Chen ◽  
Hai Dou Wang ◽  
...  

Carbon nanotubes (CNTs) have the ability to promote electron transfer reaction when used as electrode materials in electrochemical reaction owing to their high electronic conductivity. The modified glassy electrode coated with multi-walled nanotubes (MWCNTs/GC) is used to detect Electrogenerated Chemiluminescence (ECL) of Ru(bpy)32+ aqueous solution. When the applied potential on the working electrode is at at positive potential of +0.3 V (s. Ag/AgCl), a strong cathodic ECL of Ru(bpy)32+ is observed。This property of MWCNTs/GC is used to examine dopamine (DA) in solution.


Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8183
Author(s):  
Chenchen Ji ◽  
Haonan Cui ◽  
Hongyu Mi ◽  
Shengchun Yang

As newly emerged 2D layered transition metal carbides or carbonitrides, MXenes have attracted growing attention in energy conversion and storage applications due to their exceptional high electronic conductivity, ample functional groups (e.g., -OH, -F, -O), desirable hydrophilicity, and superior dispersibility in aqueous solutions. The significant advantages of MXenes enable them to be intriguing structural units to engineer advanced MXene-based nanocomposites for electrochemical storage devices with remarkable performances. Herein, this review summarizes the current advances of MXene-based materials for energy storage (e.g., supercapacitors, lithium ion batteries, and zinc ion storage devices), in which the fabrication routes and the special functions of MXenes for electrode materials, conductive matrix, surface modification, heteroatom doping, crumpling, and protective layer to prevent dendrite growth are highlighted. Additionally, given that MXene are versatile for self-assembling into specific configuration with geometric flexibility, great efforts about methodologies (e.g., vacuum filtration, mask-assisted filtration, screen printing, extrusion printing technique, and directly writing) of patterned MXene-based composite film or MXene-based conductive ink for fabricating more types of energy storage device were also discussed. Finally, the existing challenges and prospects of MXene-based materials and growing trend for further energy storage devices are also presented.


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