scholarly journals Effect of Applied Pressure on the Electrical Resistance of Carbon Nanotube Fibers

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2106
Author(s):  
Chris J. Barnett ◽  
James D. McGettrick ◽  
Varun Shenoy Gangoli ◽  
Ewa Kazimierska ◽  
Alvin Orbaek White ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Electrical Resistance ◽  
Copper Wire ◽  
Applied Pressure ◽  
Radial Strain ◽  
Electrical Current ◽  
Electrical Contacts ◽  
Electrical Performance ◽  
Macro Scale ◽  
Carbon Nanotube Fibers

Carbon nanotubes (CNTs) can be spun into fibers as potential lightweight replacements for copper in electrical current transmission since lightweight CNT fibers weigh <1/6th that of an equivalently dimensioned copper wire. Experimentally, it has been shown that the electrical resistance of CNT fibers increases with longitudinal strain; however, although fibers may be under radial strain when they are compressed during crimping at contacts for use in electrical current transport, there has been no study of this relationship. Herein, we apply radial stress at the contact to a CNT fiber on both the nano- and macro-scale and measure the changes in fiber and contact resistance. We observed an increase in resistance with increasing pressure on the nanoscale as well as initially on the macro scale, which we attribute to the decreasing of axial CNT…CNT contacts. On the macro scale, the resistance then decreases with increased pressure, which we attribute to improved radial contact due to the closing of voids within the fiber bundle. X-ray photoelectron spectroscopy (XPS) and UV photoelectron spectroscopy (UPS) show that applied pressure on the fiber can damage the π–π bonding, which could also contribute to the increased resistance. As such, care must be taken when applying radial strain on CNT fibers in applications, including crimping for electrical contacts, lest they operate in an unfavorable regime with worse electrical performance.

scholarly journals Nanocomposites conductivity point measurement using Tunneling AFM (TUNA)

2018 ◽  
Vol 233 ◽  
pp. 00022
Author(s):  
Marialuigia Raimondo ◽  
Liberata Guadagno ◽  
Luigi Vertuccio ◽  
Carlo Naddeo ◽  
Giuseppina Barra ◽  
...  
Keyword(s):  
Polymer Matrix Composites ◽  
Electrical Current ◽  
Electrical Contacts ◽  
Electrical Performance ◽  
Lightning Strike ◽  
Matrix Composites ◽  
Electron Conduction ◽  
Avant Garde ◽  
Leading Role ◽  
Structural Parts

Polymer-matrix composites containing conductive nanoparticles are a potential means for achieving an appealing combination of multifunctional properties for their use as structural parts in the aerospace field. Carbon nanofibers (CNFs) have been being looked forward to as the next generation of new and avant-garde aircraft structures because they are exceptionally coveted competitor materials to replace traditional metal components for lightning strike protection. In this regard, nanocomposites at low concentration of CNFs ranging from 0.05% up to 2% by wt to impart electron conduction in tetrafunctional epoxy resin have been prepared and characterized. The aim of this work concerns the use of Tunneling AFM (TUNA) as revolutionary tool able to correlate the electrical current map with the correspondent local morphology of CNF/resins. TUNA technique has proven to play a leading role in the identification of current paths and electrical interconnections, even without altering the morphology with usual treatments employed to create electrical contacts to the ground. Summing up, the good electrical performance together with the high mechanical properties due to a conductive cross-linked network of CNFs inside the resin demonstrate a charming applicative potential for the formulated nanocomposites as structural materials capable to provide a safe conductive path on the exterior skin, preventing serious damage to the aircraft.

scholarly journals Nickel Porous Compacts Obtained by Medium-Frequency Electrical Resistance Sintering

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2131
Author(s):  
Fátima Ternero ◽  
Eduardo S. Caballero ◽  
Raquel Astacio ◽  
Jesús Cintas ◽  
Juan M. Montes
Keyword(s):  
Electrical Resistance ◽  
Nickel Powder ◽  
Low Voltage ◽  
Applied Pressure ◽  
Electrical Current ◽  
Heating Time ◽  
Medium Frequency ◽  
Microhardness Distribution ◽  
Furnace Sintering ◽  
Porous Compacts

A commercially pure (c.p.) nickel powder was consolidated by Medium-Frequency Electrical Resistance Sintering (MF-ERS). In this consolidation technique, a pressure and the heat released by a high-intensity and low-voltage electrical current are concurrently applied to a metal powder mass. A nickel powder with a high tap porosity (86%) and a low applied pressure (only 100 MPa) is chosen in order to be able to obtain compacts with different levels of porosity, to facilitate the study of the porosity influence on the compact properties. The influence of current intensity and heating time on the global porosity values, the porosity and microhardness distribution, and the electrical conductivity of the sintered compacts is studied. The properties of the compacts consolidated by MF-ERS are compared with the results obtained by the conventional powder metallurgy route, consisting of cold pressing and furnace sintering. A universal equation to describe the porosity influence on all the analyzed properties of powder aggregates and sintered compacts is proposed and validated.

scholarly journals Influence of Rust Inhibitor on the Corrosion Resistance of Reinforcement in Cement Paste with Chloride

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 606
Author(s):  
Linchun Zhang ◽  
Ailian Zhang ◽  
Ke Li ◽  
Qian Wang ◽  
Junzhe Liu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Cement Paste ◽  
Photoelectron Spectroscopy ◽  
Electrical Resistance ◽  
Corrosion Properties ◽  
Passivation Film ◽  
Steel Bars ◽  
Assembly Unit ◽  
Chloride Environment ◽  
Rust Inhibitor

The electrical resistance and polarization effect of cement paste containing reinforcement were tested to research the anti-corrosion properties of steel bars in cement paste. Moreover, the microstructure and composition of passivation film and rust on the steel bars were studied. The water–cement ratio of the cement paste in this study was 0.3, with 0.5% NaCl, 1% NaNO2, and 1% Benzotriazole, and an assembly unit of 0.5% NaNO2 + 0.5% Benzotriazole by mass of cement was added to the cement to provide a chloride environment. X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) were applied to research the composition of the passivation film and the microstructure of the cement paste, respectively. The results indicated that the samples with the assembly unit of 0.5% NaNO2 + 0.5% Benzotriazole showed the highest electrical resistance and polarization electrical resistance, while the specimens with 1.0% Benzotriazole showed the lowest electrical resistance and polarization electrical resistance. Moreover, the passivation film of steel bars weakened with increasing distance from the surface of the steel bars. Therefore, the corrosion of steel bars becomes more serious with increasing distance. Finally, the influence of the rust inhibitor on the corrosion resistance of steel bars in the specimens decreased in the following order: 0.5% NaNO2 + 0.5% Benzotriazole >1.0% NaNO2>1.0% Benzotriazole.

High-speed electrical sliding wear behaviors of Cu-WS2-graphite-WS2 nanotubes composite

2018 ◽  
Vol 25 (2) ◽  
pp. 343-351
Author(s):  
Gang Qian ◽  
Yi Feng ◽  
Jing-Cheng Zhang ◽  
Yang Wang ◽  
Tian-Ci Zhang ◽  
...  
Keyword(s):  
Wear Rate ◽  
Contact Resistance ◽  
Photoelectron Spectroscopy ◽  
High Speed ◽  
Electrical Current ◽  
Tangential Direction ◽  
Sliding Velocity ◽  
Graphite Composite ◽  
Slip Ring ◽  
Electrical Wear

AbstractCu-WS2-graphite-WS2nanotubes composite was fabricated by the powder metallurgy hot-pressed method. The effects of electrical current (5–15 A/cm2) and sliding velocity (5–15 m/s) on the electrical wear behaviors of the composite were investigated using a block-on-slip ring wear tester rubbing against Cu-5 wt% Ag alloy ring under 2.5 N/cm2of applied load. The lubricating effect of WS2nanotubes and composition of tribo-film were analyzed. The results demonstrated that the contact resistance decreases but the wear rate increases as electrical current increases, because the adverse effects of electrical current soften the materials at “a-spots” and damage the tribo-film. Due to the adsorption of gaseous molecule film on the tangential direction of slip ring surface, with the rise of sliding velocity, the contact resistance increases while the wear rate reaches the minimum at a sliding velocity of 10 m/s. The reasonable addition of WS2nanotubes into the Cu-WS2-graphite composite to replace WS2powder can result in a reduction of both contact resistance and wear rate. X-ray photoelectron spectroscopy (XPS) analyses revealed that copper oxides, graphite, WS2and WS2nanotubes in the tribo-film play the main lubrication action at the tribo-interface.

Protection of railway infrastructure objects against electrical corrosion

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Liudmyla Trykoz ◽  
Svetlana Kamchatnaya ◽  
Dmytro Borodin ◽  
Armen Atynian ◽  
Roman Tkachenko
Keyword(s):  
Leakage Current ◽  
Electrical Resistance ◽  
Electrical Current ◽  
Leakage Currents ◽  
Destructive Effect ◽  
Accelerated Corrosion ◽  
Content Type ◽  
Pedestrian Bridges ◽  
Railway Infrastructure ◽  
Bridge Structures

Purpose The purpose of this paper is to develop a technological method of protection against electrical corrosion. One more way to protect the objects is to prevent the electrical current from getting to them. For example, railway objects are surrounded with a material with raised electrical resistance. Design/methodology/approach The railway infrastructure objects (foundations, contact-line supports, reinforced concrete sub-bases, bridge structures, pipelines of engineering networks, supports of passenger platforms and pedestrian bridges, concrete plinth walls of station buildings) are subjected to destruction due to the action of electrical current. One of destruction factors is a corrosion of the concrete constructions which is caused by the leakage current action. Findings Leakage currents and stray currents bypass the structure of supports of high passenger platforms or pipes of engineering networks. These currents spread by the line with the least resistance outside of the structures. Research limitations/implications Electrical leakage current from the rails gets into such structures through sleepers, ballast and soil and leads to accelerated corrosion leaching of concrete. Practical implications The constructions are protected against the destructive effect of electrical corrosion on the metal or concrete of the structure. This scheme is suitable for the construction and reconstruction of railway structures which operate on electrified sections of railways. Originality/value Schemes of technological solution are proposed for protection of foundations, supports of high passenger platforms, pipelines of engineering networks, etc. For this, the arrangement of soil-contained screens with big electrical resistance is suggested.

Combustion joining of refractory materials: Carbon–carbon composites

2008 ◽  
Vol 23 (1) ◽  
pp. 160-169 ◽  
Author(s):  
Jeremiah D.E. White ◽  
Allen H. Simpson ◽  
Alexander S. Shteinberg ◽  
Alexander S. Mukasyan
Keyword(s):  
Applied Pressure ◽  
Electrical Current ◽  
Carbon Composite ◽  
Carbon Composites ◽  
Refractory Materials ◽  
Temperature Combustion ◽  
Reaction Media ◽  
High Temperature Combustion ◽  
Media Layer ◽  
Reactive Media

Refractory materials such as carbon possess properties that make joining them difficult. In this work, bonding of a carbon–carbon composite is achieved by employing self-sustained, oxygen-free, high-temperature combustion reactions. The effects of several parameters, such as the composition of the reaction media, and the values of the applied current and pressure, on the mechanical strength of the joint were investigated. It was found that the C–C composite possesses a high activity with the reactive media layer, the level of electrical current used to initiate the reaction and the applied pressure do not need to be excessive to obtain a strong joint. Some aspects of the joining mechanism are discussed in detail.

Research on the delamination wear properties of the pure carbon strip at the high-sliding speed with electric current

2018 ◽  
Vol 70 (1) ◽  
pp. 76-83 ◽  
Author(s):  
Hongjuan Yang ◽  
Lin Fu ◽  
Yanhua Liu ◽  
Weiji Qian ◽  
Bo Hu
Keyword(s):  
Electric Current ◽  
High Speed ◽  
Normal Load ◽  
Copper Wire ◽  
Electrical Current ◽  
Wear Properties ◽  
Sliding Speed ◽  
Content Type ◽  
Delamination Wear ◽  
High Speed Data

Purpose This paper aims to investigate the delamination wear properties of a carbon strip in a carbon strip rubbing against a copper wire at the high-sliding speed (380 km/h) with or without electrical current. Design/methodology/approach The friction and wear properties of a carbon strip in a carbon strip rubbing against a copper wire are tested on the high-speed wear tester whose speed can reach up to 400 km/h. The test data have been collected by the high-speed data collector. The worn surfaces of the carbon strip are observed by the scanning electron microscope. Findings It was found that there was a significant increase of the delamination wear with the decrease of the normal load when the electric current is applied. The size of the flake-like peeling also increases with the decrease of normal load. The delamination wear extends gradually from the edge of the erosion pits to the surrounding area with the decrease of the normal load. However, the delamination wear never appears in the absence of electric current. It is proposed that the decreased normal load and the big electrical current are the major causes of the delamination wear of the carbon strip. Originality value The experimental test at high-sliding speed of 380 km/h was performed for the first time, and the major cause of the delamination was discovered in this paper.

scholarly journals Increased Electrical Conductivity of Carbon Nanotube Fibers by Thermal and Voltage Annealing

2021 ◽  
Vol 8 (1) ◽  
pp. 1
Author(s):  
Varun Shenoy Gangoli ◽  
Chris J. Barnett ◽  
James D. McGettrick ◽  
Alvin Orbaek White ◽  
Andrew R. Barron
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Raman Spectroscopy ◽  
Photoelectron Spectroscopy ◽  
Separate Analysis ◽  
Sweet Spot ◽  
Electrical Conductor ◽  
X Ray ◽  
Resonant Raman ◽  
Carbon Nanotube Fibers

We report the effect of annealing, both electrical and by applied voltage, on the electrical conductivity of fibers spun from carbon nanotubes (CNTs). Commercial CNT fibers were used as part of a larger goal to better understand the factors that go into making a better electrical conductor from CNT fibers. A study of thermal annealing in a vacuum up to 800 °C was performed on smaller fiber sections along with a separate analysis of voltage annealing up to 7 VDC; both exhibited a sweet spot in the process as determined by a combination of a two-point probe measurement with a nanoprobe, resonant Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Scaled-up tests were then performed in order to translate these results into bulk samples inside a tube furnace, with similar results that indicate the potential for an optimized method of achieving a better conductor sample made from CNT fibers. The results also help to determine the surface effects that need to be overcome in order to achieve this.

scholarly journals High Loading Capacity and Wear Resistance of Graphene Oxide/Organic Molecule Assembled Multilayer Film

2021 ◽  
Vol 9 ◽  
Author(s):  
Li Chen ◽  
Gang Wu ◽  
Yin Huang ◽  
Changning Bai ◽  
Yuanlie Yu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Multilayer Films ◽  
Thickness Measurement ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Film Structure ◽  
Silicon Substrates ◽  
Water Contact ◽  
Macro Scale

Taking advantage of the strong charge interactions between negatively charged graphene oxide (GO) sheets and positively charged poly(diallyldimethylammonium chloride) (PDDA), self-assembled multilayer films of (GO/PDDA)n were created on hydroxylated silicon substrates by alternating electrostatic adsorption of GO and PDDA. The formation and structure of the films were analyzed by means of water contact angle measurement, thickness measurement, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). Meanwhile, tribological behaviors in micro- and macro- scale were investigated by AFM and a ball-on-plate tribometer, respectively. The results showed that (GO/PDDA)n multilayer films exhibited excellent friction-reducing and anti-wear abilities in both micro- and macro-scale, which was ascribed to the special structure in (GO/PDDA)n multilayer films, namely, a well-stacked GO–GO layered structure and an elastic 3D crystal stack in whole. Such a film structure is suitable for design molecular lubricants for MEMS and other microdevices.

Joining of Carbon Nanotube Fiber by the Meniscus-Confined Electrochemical Deposited Silver

NANO ◽  
2021 ◽  
pp. 2150071
Author(s):  
Qian Zhang ◽  
Yang Li ◽  
Yecheng Wang ◽  
Sunusi Marwana Manladan ◽  
Sansan Ao ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Electrochemical Deposition ◽  
Electrical Resistance ◽  
High Strength ◽  
Fracture Load ◽  
Low Resistance ◽  
Carbon Nanotube Fiber ◽  
Uniform Microstructure ◽  
Wide Range ◽  
Carbon Nanotube Fibers

To use carbon nanotube fibers (CNT) extensively in a wide range of electrical and electronic applications, an essential key step is to produce a low-resistance, high-strength and reliable connection between the CNT fibers and other live parts in the circuit. In this study, meniscus-confined electrochemical deposition (ECD) process with silver was proven to be a practical way of joining CNT fibers together head-to-head. The whole ECD process was stable. The shape of the joints was found to depend on the shape of the tips of the CNT fibers. The deposited silver exhibited a dense and uniform microstructure and it was tightly bound to the CNT fibers, with a distinct interface between them. In the ECD process, the original morphology of the CNT network was maintained. The lowest electrical resistance of the CNT fibers joints was measured to be 8.72[Formula: see text][Formula: see text], which is 45% lower than that of the original CNT fibers. The deposited joint sustained a fracture load of 7.5cN with an elongation of 0.4%.

Sign in / Sign up

Export Citation Format

Share Document