• Composites Research
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• v.23 no.6
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• pp.1-6
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• 2010

The electrical conductivity of carbon-fiber reinforced plastics (CFRP's) has been improved by indium-tin oxide (ITO) nano-particle coating on carbon fibers for the purpose of lightning strike protection of composite fuselage skins. ITO nano-particles were coated on the surface of carbon fibers by spraying the colloidal suspension with 10~40% ITO content. The electrical conductivity of the CFRP has been increased more than three times after ITO coating, comparable to or higher than that of B-787 composite fuselage skins with metal wire-meshes on the outer surface, without sacrificing the tensile property due to the existence of nano-particles at fiber-matrix interface. The damage area by the simulated lightning strike was also verified for different materials and conditions by using ultrasonic C-scan image. As the electrical conductivity of 40% nano-ITO coated sample surpass that of the B-787 sample, the damage area by lightning strike also appeared comparable to that of the materials currently employed for composite fuselage construction.

• Journal of Electrochemical Science and Technology
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• v.12 no.2
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• pp.204-211
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• 2021

We report, synthesis of high surface area composite carbon aerogel using additive based polymerization technique by incorporating graphitic porous carbon as additive. This additive was separately prepared using sol-gel polymerization of resorcinol-furfuraldehyde in iso-propyl alcohol medium at much above the routine gelation temperature to yield porous carbon (CA-IPA) having graphitic layered morphology. CA-IPA exhibited a unique combination of meso-pore dominated surface area (~ 700 m²/g) and good conductivity of ~ 300 S/m. The composite carbon aerogel (CCA) was synthesized by traditional aqueous medium based resorcinol-formaldehyde gelation with CA-IPA as additive. The presence of CA-IPA favored enhanced meso-porosity as well as contributed to improvement in bulk conductivity. Based on the surface area characteristics, CCA-8 composition having 8% additive was found to be optimum. It showed specific surface area of ~ 2056 m²/g, mesopore area of 827 m²/g and electrical conductivity of 180 S/m. The electrode formed with CCA-8 showed improved electrochemical behavior, with specific capacitance of 148 F/g & ESR < 1 Ω, making it a better choice as super capacitor for energy storage applications.

• Journal of Electrochemical Science and Technology
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• v.14 no.4
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• pp.377-387
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• 2023

Ni-W/Al₂O₃ nano-composites were electrodeposited on mild steel substrate for mechanical and corrosion resistance applications. This study focused on the preparation of Ni-W/Al₂O₃ nano-composite coating with various quantity of Al₂O₃ incorporations. The addition of Al₂O₃ in the electrolytes were varied from 1-10 g/L in electrolytes and the Al₂O₃ incorporation in Ni-W/Al₂O₃ nano-composite coatings were obtained from 1.82 to 13.86 wt.%. The incorporation of Al₂O₃ in Ni-W alloy matrix influenced the grain size, surface morphology and structural properties were observed. The distributions of Al₂O₃ particle in alloy matrix were confirmed using electron microscopy (FESEM and TEM) and EDAX mapping analysis. The crystal structure informations were studied using X-ray diffraction method and it confirms that the deposits having cubic crystal structure. The better corrosion rate (0.87 mpy) and microhardness (965 HV) properties were obtained for the Ni-W/Al₂O₃ nano-composite coating with 13.86 wt.% of Al₂O₃ incorporations.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.11
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• pp.1251-1258
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• 2011

With the help of nanoscale materials like carbon nanotube (CNT), there is the potential to develop new actuators that will provide higher work per cycle than previous actuator technologies, and generate much higher mechanical strength. In this study, the electrochemical actuation characteristics of nano carbon materials were experimentally studied to develop electrochemical actuators. The electrochemical actuators were composed of aqueous NaCl electrolyte and their actuating electrodes were made of multi-walled carbon nanotube (MWCNT)/polystyrene composite and graphene respectably. Actuation is proportional to charging transfer rate, and the electrolysis with an AC voltage input has very complex characteristics. To quantify the actuation property, the strain responses and output model were studied based on electrochemical effects between the nano carbon films and the electrolyte.

• Transactions on Electrical and Electronic Materials
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• v.12 no.3
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• pp.98-101
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• 2011

A 10 nm nano-silica was introduced to a conventional 3 ${\mu}M$ micro-silica composite to develop an eco-friendly new electric insulation material for heavy electric equipment. Thermal and mechanical properties, such as glass transition temperature (Tg), dynamic mechanical analysis, tensile and flexural strength, were studied. The mechanical results were estimated by comparing scale and shape parameters in Weibull statistical analysis. The thermal and mechanical properties of conventional epoxy/micro-silica composite were improved by the addition of nano-silica. This was due to the increment of the compaction via the even dispersion of the nano-silica among the micro-silica particles.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.613-619
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• 2006

This paper introduces a new structural health monitoring using a nano sensor. The sensor is made of nano smart composite material based on carbon nanotubes. The nano sensor is fabricated as a thin and narrow polymer film sensor that is bonded or deposited onto a structure. The electrochemical impedance and dynamic strain response of the neuron change due to deterioration of the structure where the sensor is located. A network of the long nano sensorcan form a structural neural system to provide large area coverage and an assurance of the operational health of a structure without the need for actuators and complex wave propagation analyses that are used with other methods.

• Advances in materials Research
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• v.7 no.3
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• pp.185-194
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• 2018

The mechanism of biological materials structure is very complex and has optimal properties compared to engineering materials. Top Neck mollusks shells, as an example of biological materials, have hierarchical structure, which 95 percent of its structure is Aragonite and 5 percent organic materials. This article detected mechanical properties of the Top Neck mollusks shell as a Nano composite using Nano-indentation method in different situations. Research findings indicate that mechanical properties of the Top Neck mollusks shell including elastic modulus and hardness are higher than a fresh one preserved in -50 centigrade and also a Top Neck mollusks shell preserved in environmental conditions. Nano-indentation test results are so close in range, overall, that hardness degree is 3900 to 5200 MPa and elastic modulus is 70 to 85 GPa.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2003.10a
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• pp.142-142
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• 2003

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.487-488
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• 2006

Novel bisphenol-based wholly aromatic poly(ether sulfone-ketone) copolymer containing pendant sulfonate groups were prepared by direct aromatic nucleophilic substitution polycondensation of 4,4-difluorobenzophenone, 2,2'-disodiumsulfonyl-4,4'-fluorophenylsulfone (40mole% of bisphenol A) and bisphenol A. Polymerization proceeded quantitatively to high molecular weight in N-methyl-2-pyrrolidinone at $180^{\circ}C$. Organic-inorganic composite membranes were obtained by mixing organic polymers with hydrophilic $SiO_2$ (ca. 20nm) obtained by sol-gel process. The polymer and a series of composite membranes were studied by FT-IR, $^1HNMR$, differential scanning calorimetry (DSC) and thermal stability. The proton conductivity as a function of temperature decreased as $SiO_2$ content increased, but methanol permeability decreased. The nano composite membranes were found to posse all requisite properties; Ion exchange capacity (1.2meq./g), glass transition temperatures $(164-183\;^{\circ}C)$, and low affinity towards methanol $(4.63-1.08{\times}10^{-7}\;cm^2/S)$.

• Journal of the Korean institute of surface engineering
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• v.40 no.2
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• pp.70-76
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• 2007

Ni-P-SiC composite coating layers were prepared by electroless plating method and their deposition rate, codeposition of SiC, morphology, surface roughness, hardness, wear and friction properties were investigated. The deposition rate was kept almost constant independent of the concentration of SiC in the plating solution and the codeposition of SiC in the composite coating layer increased with increased concentration of SiC in the plating solution except the early stage. Vickers microhardness increased with respect to the increased codeposition of SiC and the heat treatment at $300^{\circ}C$ in air for 1 hour. It was found that the wear volume decreased with increased up to 50 wt.% of SiC codeposition, and that friction coefficient increased gradually with increased codeposition of SiC. Considering the wear and the friction behaviors, the composite coating layer obtained by using 50 wt.% of SiC codeposition is desirable for the practical application for anti-wear and anti-friction coatings.