Nickel-coated Carbon Nanotubes Research Articles

Dynamic behaviors of nickel coated carbon nanotubes reinforced ultra-high performance cementitious composites under high strain rate impact loading

Understanding the dynamic mechanical behaviors of materials is a prerequisite for reliably analyzing and predicting the dynamic response of structures, which is of great significance for transportation infrastructure and military engineering subjected to extreme loads, particularly dynamic loads at high strain rates. Nickel coated multi-walled carbon nanotubes (Ni-MWCNTs) show promise as a reinforcement to modify the dynamic mechanical behaviors of ultra-high performance cementitious composites (UHPCC). Because Ni-MWCNTs combine the high tensile strength and large aspect ratio characteristics of fibers with the nano effect of nanomaterials, as well as have excellent dispersibility due to the nickel plating on the CNTs’ surface, they effectively improve the dynamic mechanical properties of UHPCC under impact loading at high strain rates of about 100 s−1/300 s−1/500 s−1 and reduce the brittle damage degree of composites. The maximal increase in dynamic compressive strength and energy absorption capacity of UHPCC reaches 47.9% and 68.2%, respectively. This enhancement effect arises from that Ni-MWCNTs improve the microstructure and form multiple fine cracks, resulting in an increased energy consumption required for crack formation, propagation and coalescence. Additionally, the dynamic mechanical properties of Ni-MWCNTs reinforced UHPCC exhibit noticeable strain rate effects. Consequently, a strain rate-dependent logarithmic functional dynamic increase factor model and dynamic constitutive model of UHPCC filled with Ni-MWCNTs are modified herein for predicting and modeling the dynamic mechanical behaviors of composites.

Synthesis and application of NiLa-layered double hydroxides on nickel-coated carbon nanotubes with Co-ZIF-67 composite in supercapacitors

Owing to the global climate emergency, there is considerable interest in new energy generation and storage solutions. Supercapacitors have many desirable properties of particular interest for energy storage. However, they have low energy densities, which must be improved. Materials based on zeolite imidazole skeletons (ZIFs) have uniform pores, large specific surface areas, and simple structures. Moreover, Co-ZIF-67 has high electrical conductivity, which makes it a promising candidate for energy storage applications. In this study, a Co-ZIF-67 precursor with a regular cubic structure is synthesized. This precursor is combined with Ni-coated carbon nanotubes (Ni-CNTs) and NiLa-layered double hydroxides (NiLa-LDHs). Thus, by controlling the hydrothermal reaction time, an electrode material with a nanosheet structure is applied to the CNTs. Electrochemical analysis shows that the resulting Co-ZIF-67/Ni-CNT@NiLa-LDH composite has a specific capacitance of 1710 F g−1 at a current density of 1 A g−1. The composite is combined with activated carbon (AC) to produce a Co-ZIF-67/Ni-CNT@NiLa-LDH//AC asymmetric supercapacitor, which exhibits outstanding capacitive performance (150.1 F g−1 at a current density of 1 A g−1), a wide operating voltage window (1.7 V), and outstanding stability.

Effect of nickel-coated carbon nanotubes on the tensile behaviors of ultra-high performance concrete (UHPC): insights from experiments and molecular dynamic simulations

Effect of nickel-coated carbon nanotubes on the tensile behaviors of ultra-high performance concrete (UHPC): insights from experiments and molecular dynamic simulations

Enhanced dielectric and mechanical properties of polylactic acid/polycaprolactone blends by introducing double‐layer carbon nanofillers

AbstractTo overcome the issues of poor toughness and low dielectric constant associated with PLA, which limit its application in the electronics industry, we introduced an insulating polydopamine (PDA) layer on the surface of core‐shell nickel‐coated carbon nanotube (Ni‐CNT) and nickel‐coated graphene (Ni‐GRA). Through a double‐layer structural design approach, we successfully prepared polylactic acid (PLA)/polycaprolactone (PCL) blends that exhibit high dielectric constant (ε’) and low dielectric loss (tanδ). This innovative design led to impressive impact strengths of 29.41 kJ/m2 for PLA/PCL/4Ni‐GRAs and 22.54 kJ/m2 for PLA/PCL/4Ni‐CNTs. PDA enhanced the interfacial interactions between the filler and matrix, which improved the dispersion of Ni‐CNTs and Ni‐GRAs and contributed to the mechanical properties of the PLA/PCL blends. Simultaneously, PLA/PCL/4Ni‐CNTs and PLA/PCL/4Ni‐GRAs exhibited commendable integrated dielectric properties. The PDA@fillers form microcapacitors with the polymer matrix and the conductive Ni layer enhances ε’ and reduces the conductivity difference between fillers. Furthermore, the insulating PDA layer contributed to improved dispersion, inhibition of charge carrier migration, and reduction in tanδ. At 1000 Hz, the ε′ of PLA/PCL/4Ni‐CNTs and PLA/PCL/4Ni‐GRAs increased to 88.3 and 124.6, respectively, and the tanδ values remained below 1, indicating minimal dielectric loss. This provides a promising direction for eco‐friendly materials with enhanced dielectric and mechanical properties.

Mode II cohesive zone law of porous sintered silver joints with nickel coated multiwall carbon nanotube additive under ENF test

Various contents of nickel coated carbon nanotube added sintered silver joints are fabricated through mechanical alloying. An analytical method is presented to compute the fracture energy of ENF tests incorporating shearing effect and thickness effect, which shows better accuracy compared with traditional method, which are closer to the solutions of compliance based beam method. Mode II fracture energy, mode II fracture toughness and mode II cohesive zone model for different contents of nickel coated carbon nanotube added sintered silver joints are presented based on the data extraction of the ENF tests. With the increase of adhesive layer thickness, the fracture energy and the mode II fracture toughness improve. However, thickness effect is less significant but not negligible comparing with the strengthening effect on the improvement of fracture toughness, which is caused by adding nickel coated multiwall carbon nanotubes. The relation between mode II fracture toughness and porosity is also discussed. For most of the conditions, the mode II fracture toughness is higher than mode I fracture toughness regardless of additive content due to the crack deflection, crack bridging and pull-out mechanisms during the crack propagation except for those high content of additive whose fracture energy is reduced because of aggregation effect.

Effect of nickel-coated carbon nanotubes on the preparation and wear resistance of microarc oxidation ceramic coating on ZL109 aluminum alloy

In order to adapt to the development of lightweight equipment, and further improve the wear resistance of ZL109 aluminum alloy, the influence of nickel-coated carbon nanotubes as an electrolyte additive on the preparation and wear resistance of microarc oxidation ceramic coatings on ZL109 aluminum alloy surface was investigated. In this work, 0.4 g/L, 0.8 g/L, 1.2 g/L, 1.6 g/L, and 2 g/L nickel-coated carbon nanotubes were added to the electrolyte respectively. The microarc oxidation ceramic coatings were prepared under bipolar pulse constant pressure mode, which were analyzed from the aspects of morphology, chemical composition, and wear resistance property. The results show that the nickel-coated carbon nanotubes possess a great influence on ceramic coatings. The morphology of ceramic coatings was significantly changed. In this work, the coating prepared by 1.2 g/L nickel-coated carbon nanotubes exhibits excellent wear resistance property.

Pore structure characteristics of concrete composites with surface-modified carbon nanotubes

The macroscopic properties of carbon nanotubes (CNTs) modified reactive powder concrete (RPC) composites are closely related to their pore structure characteristics, but the structural nature of PRC composites and the effect of CNTs on their pore structure remain unclear. To comprehensively understand the pore structure of RPC composites with surface-modified CNTs and then control their properties, both the mercury intrusion porosimetry (MIP) and low-field nuclear magnetic resonance (LF-NMR) technologies were used to characterize the pore structure characteristics of RPC composites. Experimental results showed there exist large number of nano-scale pores (mainly interlayer and gel pores) with the radius range of 0.3–20 nm in RPC composites. All types of surface-modified CNTs incorporated in this study reduce the pore content and size of RPC composites, thereby modifying the pore structure of RPC. However, different CNTs present varying effects on the pore (especially nano-scale pore) structure characteristics. Among all surface-modified CNTs, the hydroxyl functionalized and nickel-coated CNTs cause the structural shrinkage of C-S-H gel, while the carboxyl functionalized CNTs induce the transformation of some nano-scale pores inside the gel. The effects of surface-modified CNTs on the pore structure of RPC composites are mainly on the nano- and micrometer scale. CNTs can not only increase the matrix compactness of RPC composites and enhance the network structure of hydration products, but also induce the pore water conversion inside C-S-H layers.

Compressive properties and underlying mechanisms of nickel coated carbon nanotubes modified concrete

Nickel coated multi-walled carbon nanotubes (Ni-MWCNTs) having exceptional mechanical properties, thermal conductivity and dispersibility can effectively overlap in cementitious matrix, thus forming an enhanced and thermal conductive network. They are therefore a promising nanofiller for modifying cement and concrete materials. This paper studies the compressive properties of reactive powder concrete (RPC) filled with different aspect ratios of Ni-MWCNTs, including strength, toughness, Young's modulus and Poisson’s ratio. It is concluded that the incorporation of 0.06 vol.% Ni-MWCNTs with an aspect ratio of 1500 maximally increases the compressive strength and toughness of RPC by 20.24%/20.39 MPa and 43.89%/56.35 (N·m), respectively. However, Young's modulus and Poisson's ratio of Ni-MWCNTs modified composites do not significantly be improved. Besides, a constitutive model of Ni-MWCNTs reinforced RPC under uniaxial compression is established based on the continuum damage mechanics theory, reasonably predicting the relationship between compressive strength and deformation of composites. The modification mechanism of Ni-MWCNTs is also investigated through the temperature distribution monitoring inside composites, Scanning Electron Microscope (SEM) observation and energy dispersive x-ray spectrometry (EDS) analysis of Ni-MWCNTs reinforced RPC. The thermal conductive network formed by Ni-MWCNTs in matrix reduces the temperature difference and improves the temperature uniformity inside composites, thereby decreasing thermal stresses, primary cracks and defects of composites. Furthermore, the incorporation of Ni-MWCNTs makes the RPC microstructures dense, decreases the average CaO to SiO2 ratio, and inhibits the development of cracks inside RPC, thus achieving effective enhancement to RPC.

Investigating the compatibility of nickel coated carbon nanotubes and cementitious composites through experimental evidence and theoretical calculations

Nickel coated multi-walled carbon nanotubes (NiMCNTs) are favorable reinforcing nanofillers for modifying cementitious composites due to their preeminent mechanical properties, electrical conductivity, thermal properties and dispersibility. This paper investigates the mechanical properties and compatibility of NiMCNTs filled cementitious composites, having two different types of cement, two water to cement ratios, and two dosages of five types of NiMCNTs. The results show that 0.06 vol% NiMCNTs with small aspect ratios can significantly enhance the mechanical properties of cementitious composites, while NiMCNTs with large aspect ratios play a better strengthening effect at 0.03 vol%. The flexural strength/toughness of cementitious composites containing 0.06 vol% NiMCNTs with an aspect ratio of 200 can be increased by 19.65%/116.78%. Adding 0.03 vol% NiMCNTs with an aspect ratio of 1000 enhances the compressive strength/toughness of composites by 18.61%/47.44%. Besides, NiMCNTs have preferable compatibility to cementitious composites prepared by P·O 42.5R cement with a water to cement ratio of 0.3. The enhancement mechanism is related to the denser microstructure and effective suppression of microcracks in the cementitious matrix by NiMCNTs with filling, bridging and pull-out effects, as well as the high interface bond strength between NiMCNTs and matrix. A strength prediction model for NiMCNTs reinforced cementitious composites is also established to estimate the mechanical strength of cementitious composites containing NiMCNTs with different aspect ratios/contents, showing a small relative error within ±6%/±13% for predicted flexural/compressive strength values in comparison with the experimental results.

Improved conductivity and piezoresistive properties of Ni-CNTs cement-based composites under magnetic field

A novel type of cement-based composite with preferentially orientated nickel-coated carbon nanotubes (Ni-CNTs) was fabricated by induction of magnetic field (MF) method for piezoresistive sensor in structural health monitoring system. The microstructures of Ni-CNTs and their aligned features in the as-fabricated composites were observed by scanning electron microscope (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The four-electrode method was applied to measure the conductivity and piezoresistive properties of as-fabricated composites. Besides, the effects of several influencing factors, including Ni-CNTs orientation and content, loading rate on the conductivity and piezoresistive properties of Ni-CNTs cement-based composites were determined. The results indicate that the CNTs coated with crystalline nickel are orientated preferentially along the MF direction, of which the orientation angles are concentrated between −30°-20°, presenting a Gaussian distribution. The conductivity and piezoresistive properties of oriented Ni-CNTs cement-based composites are anisotropic. The electrical resistivity and percolation threshold of composites have a sequence: perpendicular to MF > without MF > parallel to MF. Under cyclic compressive loading, Ni-CNTs cement-based composites parallel to MF direction exhibit the best piezoresistive properties. The optimum content level of CNT for the piezoresistivity is 1.20 vol%, which is slightly higher than the percolation threshold. Also, the strain sensitivity of composites parallel to MF is most sensitive to the loading rate.

Free Transverse Vibration of Nickel Coated Carbon Nanotubes

Transverse vibration of nickel coated carbon nanotubes is investigated by using molecular dynamics simulations. The simulations are carried out for armchair and zig-zag carbon nanotubes with various lengths. Uncoated and nickel coated carbon nanotubes having same lengths are analyzed and their vibrational behaviors are compared. Free transverse vibrations of nickel coated carbon nanotubes are modelled by using a two-phase local–nonlocal Euler–Bernoulli beam model and solved by finite element method. Nonlocal parameter of the beam model is calibrated based on molecular dynamics simulation results. It is seen that for the same length diameter ratio, the nickel coated carbon nanotubes have similar vibrational characteristics with the uncoated carbon nanotubes but their natural frequencies are smaller than the uncoated ones. Also, it is shown that by using proper nonlocal parameters for each radius length ratio, the two-phase local–nonlocal Euler–Bernoulli beam model can successfully predict the natural frequencies of both short and long nanotubes. Besides natural frequencies and mode shapes, the clustering of nickel atoms depend on simulation temperature which is discussed during oscillation of nickel coated carbon nanotubes.

联氨还原法制备镍包覆碳纳米管复合材料

联氨还原法制备镍包覆碳纳米管复合材料

Study on Plastic Strengthening Mechanisms of Aluminum Matrix Nano-Composites Reinforced by Nickel Coated CNTs

ABSTRACT The mechanical strength of pure aluminum matrix can be greatly enhanced by adding a small amount of nickel-coated carbon nanotubes (NiCNTs), where the nickel coating helps to the uniform dispersion of carbon nanotubes (CNTs) within the aluminum matrix through decreasing density difference and avoiding CNTs agglomeration. The yield strength of pure aluminum can be increased by 33.3% with 1% weight fraction of NiCNTs. This strengthening effect is caused by three mechanisms: Orowan looping, load bearing, and thermal expansion mismatch which are studied by both finite-element method and analytical method. A series of finite-element analyses using a representative volume element (RVE) method are conducted considering influences of CNTs aspect ratios, volume fraction of hardened zone, and the hardened plastic strain of hardened zone. The results show that the aspect ratio of CNTs is very important in the strengthening of CNT-reinforced composites, and the yield stress increases with increasing aspect ratio. A set of parameters for analytical solutions are optimized that can well describe and accurately predict the experimental data. Both the finite-element analysis and analytical solution are well correlated with the experimental results for Al/NiCNT composites with different weight fractions of CNTs.

Study on the tensile and wear properties of laser-cladded IN718 superalloy reinforced by carbon nanoproducts transformed from carbon nanotubes

Abstract

A review: microstructure and properties of tin-silver-copper lead-free solder series for the applications of electronics

Purpose The research on lead-free solder alloys has increased in past decades due to awareness of the environmental impact of lead contents in soldering alloys. This has led to the introduction and development of different grades of lead-free solder alloys in the global market. Tin-silver-copper is a lead-free alloy which has been acknowledged by different consortia as a good alternative to conventional tin-lead alloy. The purpose of this paper is to provide comprehensive knowledge about the tin-silver-copper series. Design/methodology/approach The approach of this study reviews the microstructure and some other properties of tin-silver-copper series after the addition of indium, titanium, iron, zinc, zirconium, bismuth, nickel, antimony, gallium, aluminium, cerium, lanthanum, yttrium, erbium, praseodymium, neodymium, ytterbium, nanoparticles of nickel, cobalt, silicon carbide, aluminium oxide, zinc oxide, titanium dioxide, cerium oxide, zirconium oxide and titanium diboride, as well as carbon nanotubes, nickel-coated carbon nanotubes, single-walled carbon nanotubes and graphene-nano-sheets. Findings The current paper presents a comprehensive review of the tin-silver-copper solder series with possible solutions for improving their microstructure, melting point, mechanical properties and wettability through the addition of different elements/nanoparticles and other materials. Originality/value This paper summarises the useful findings of the tin-silver-copper series comprehensively. This information will assist in future work for the design and development of novel lead-free solder alloys.

Nickel coated carbon nanotubes in aluminum matrix composites: a multiscale simulation study

In this work we use density functional theory (DFT) calculations to benchmark empirical potentials for the interaction between nickel and sp$^2$ bonded carbon nanoparticles. These potentials are then used in order to investigate how Ni decorated or coated carbon nanotubes (CNT) affect the mechanical properties of Al/CNT composites. In particular we look at the pull-out behaviour of pristine as well as Ni-decorated and Ni-coated CNT from an Al matrix. Our result shows that Ni coating may produce an extended interface (interphase) where a significant amount of energy is dissipated during CNT pull-out, leading to a high pull-out force. We also demonstrate that surface decorated CNT may act as efficient nano-crystallization agents and thus provide a novel strengthening mechanism not previously discussed in the literature. We discuss our results in view of promising approaches for engineering CNT-metal interfaces such as to achieve high strength metal-CNT composite.

Preparation and corrosion resistance of titanium-zirconium/nickel-coated carbon nanotubes chemical nano-composite conversion coatings

Purpose This study aims to expand the reliability and special functions of lightweight materials for high-end equipment and green manufacturing, so that it is the first such research to carry out nano-composite technology of nickel-coated carbon nanotubes (Ni-CNTs)-based titanium-zirconium chemical conversion on aluminum alloy substrate. Design/methodology/approach Corrosion behavior of various coatings was investigated using dropping corrosion test, linear polarization and electrochemical impedance spectroscopy. The results showed that the corrosion resistance of the nano-composite conversion coatings was significantly improved to compare with the conventional titanium-zirconium conversion coating. The morphology and microdomain characteristics of the nano-composite conversion coatings were characterized by SEM/eds/EPMA, which indicated that the CNT or Ni-CNTs addition promoting the integrity coverage of coatings in a short time. Findings Surface morphology of titanium-zirconium (Ti-Zr)/Ni-CNT specimens exhibited smooth, compact and little pores. The nano-composite conversion coatings are mainly composed of Al, O, C and Ti elements and contain a small amount of F and Zr elements, which illuminated that CNT or Ni-CNT addition could co-deposit with aluminum and titanium metal oxides. Originality/value The study of corrosion resistance of nano-composite conversion coatings and the micro-zone film-formation characteristics would be provided theoretical support for the development of basic research on surface treatment of aluminum alloys.

Friction and wear characteristics of copper nanocomposites reinforced with uncoated and nickel coated carbon nanotubes

In the present work we report the development of carbon nanotube having multi-walls reinforced copper nanocomposites. The carbon nanotubes were used in both uncoated and nickel coated conditions to reinforce copper matrix. The nanocomposites with different carbon nanotubes (0.25 to 1.0) weight percentage were developed using a combination of ultrasonication, ball milling, sintering and upsetting forging processes. The developed nanocomposites were subjected to microstructural characterization using scanning and transmission electron microscopes to observe the dispersion of carbon nanotubes. The effect of carbon nanotubes on friction and wear properties of copper nanocomposites were studied using pin on disc testing rig as per ASTM G99 standard. The coefficient of friction of both 1 wt% uncoated and nickel coated carbon nanotubes reinforced nanocomposites was found to drop by 60.41% and 70.83% respectively when compared to copper. Similarly the wear rate of nanocomposites were found to decrease with the incoporation of carbon nanotubes. The low coefficient of friction and wear rate were attributed to uniform dispersion of carbon nanotubes and formation of carbonaceous layer on the surface of nanocomposites during dry sliding wear.

Compelling mechanical properties of carbon nanotubes reinforced pure magnesium composite by effective interface bonding of Mg2Ni

In this study, a kind of nickel coated carbon nanotubes (Ni-CNTs) reinforced pure magnesium (Mg) matrix composite was prepared using two-step process. The nano-Mg2Ni phase at the interface was in-situ formed to improve the interface bonding between CNTs and Mg matrix. Results indicated that the yield and ultimate tensile strength of 2.0 wt. % Ni-CNTs/Mg composite were 278.3 MPa and 304.5 MPa, respectively, showing 77% and 48% increase in comparison with those of 2.0 wt. % CNTs/Mg composite. The remarkably enhanced mechanical properties were attributed to the strong interface bonding due to the in-situ formed nano-Mg2Ni phase. The corresponding strengthening mechanisms were regarded as the coupling interface effect of the coherent interface and the interstitial solid solution. Moreover, the CNTs acted as a bridging role in load transfer and obstructed the growth of cracks in Ni-CNTs/Mg composites.

Nickel oxide nanotube synthesis using multiwalled carbon nanotubes as sacrificial templates for supercapacitor application

A novel approach for the fabrication of nickel oxide nanotubes based on multiwalled carbon nanotubes as a sacrificial template is described. Electroless deposition is employed to deposit nickel onto carbon nanotubes. The subsequent annealing of the product in the presence of air oxidizes nickel to nickel oxide, and carbon is released as gaseous carbon dioxide, leaving behind nickel oxide nanotubes. Electron microscopy and elemental mapping confirm the formation of nickel oxide nanotubes. New chelating polyelectrolytes are used as dispersing agents to achieve high colloidal stability for both the nickel-coated carbon nanotubes and the nickel oxide nanotubes. A gravimetric specific capacitance of 245.3 F g−1 and an areal capacitance of 3.28 F cm−2 at a scan rate of 2 mV s−1 is achieved, with an electrode fabricated using nickel oxide nanotubes as the active element with a mass loading of 24.1 mg cm−2.