• Design & Manufacturing
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• v.14 no.4
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• pp.71-77
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• 2020

Various manufacturing technologies, including over-molding and insert-injection molding, are used to produce hybrid plastics and metals. However, there are disadvantages to these technologies, as they require several steps in manufacturing and are limited to what can be reasonably achieved within the complexities of part geometry. This study aims to determine a practical approach for producing metal/plastic hybrid components by combining plastic injection molding and metal die casting to create a new hybrid metal/plastic molding process. The integrated metal/plastic hybrid injection molding process developed in this study uses the proven method of multi-component technology as a basis to combine plastic injection molding with metal die casting into one integrated process. In this study, the electrical conductivity and ampacity were verified to qualify the new process for the production of parts used in electronic devices. The electrical conductivity was measured, contacting both sides of the test sample with constant pressure, and the resistivity was measured using a micro ohmmeter. Also, the specific conductivity was subsequently calculated from the resistivity and contact surface of the conductor path. The ampacity defines the maximum amount of current a conductive path can carry before sustaining immediate or progressive deterioration. The manufactured hybrid multi-components were loaded with increasing currents, while the temperature was recorded with an infrared camera. To compare the measured infrared images, an electro-thermal simulation was conducted using commercial CAE software to predict the maximum temperature of the power loaded parts. Overall, during the injection molding process, it was demonstrated that multifunctional parts can be produced for electric and electronic applications.

• Korean Journal of Materials Research
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• v.11 no.4
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• pp.312-318
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• 2001

The mechanical and electrical properties of Cu-Nb filamentary nanocomposite fabricated by the bundling and drawing process were examined. The strength increased gradually with increasing Nb content while the ductility was insensitive to Nb content. The ratio of yield stresses at 293K and 75K are found to be 치ose to that of Young's moduli in various Cu-Nb nanocomposites, suggesting that athermal obstacles primarily control the strength. The fracture morphologies show ductile fractures irrespective of Nb contents. Secondary cracking along the interfaces between subelemental wires was occasionally observed and the frequency of secondary cracking increased with increasing Nb content. The conductivity and the resistivity ratio decreased with increasing Nb content. The decrease of the conductivity and the resistivity ratio(${\rho}_{293k}$/$\{rho}_{75k}$) can be explained by the increasing contribution of interface scattering.

• Composites Research
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• v.17 no.5
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• pp.61-67
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• 2004

This paper reports the electrical conductivity and the stress-strain behavior of silver particle-filled silicone composite pastes for electromagnetic interference (EMI) shielding gasket materials. The percolation threshold (critical concentration) of the composite paste obtained by incorporating irregular sphere-shaped silver particles and room temperature vulcanizing (RTV) silicone resin was determined from the electrical conductivity result. At about 28 vol% Beading of untreated silver particles, the percolation phenomenon occurred and at this critical concentration, the volumetric resistivity, the tensile strength, and the elongation of the pastes were investigated. This work also suggests that the stress-strain characteristics of a composite paste filled with metal particles above the percolation threshold may be effectively improved by properly selecting a coupling agent.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.5
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• pp.407-413
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• 2005

Ion implantation provides a unique way to modify the mechanical, optical and electrical properties of polymer by depositing the energy of ions in the material on the atomic scale. Implantation of ions into the polymers generally leads to a radiation damage, which, in many cases, modifies the properties of the surface and bulk of the material. These modifications result from the changes of the chemical structure caused in their turn by changing the chemical bonding when the incident ions cut the polymer chains, breaks covalent bonds, promotes cross-linking, and liberates certain volatile species. We studied the relation among the linear energy transfer (LET) and changes of surface microstructure and surface resistivity on PPS material using the high current ion implantation technology The surface resistivity of nitrogen implanted PPS decreased to $10^{7}{\Omega}/cm^{2}$ due to the chain scission, cross linking, ${\pi}$ electron creation and mobility increase. In this case, the surface conductivity depend on the 1-dimensional hopping mechanism.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.5
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• pp.172-177
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• 1999

In this paper, the physical and electrical properties of the synthetic fluids No. 2 class Ⅶ used the insulating oils for automobile ignition coil are studied. Also, benzotriazole(BTA) as the streaming electrification suppressant additive is added to the oil, and the change of physical and electrical properties due to different BTA concentration is investigated. To investigate the electrical characteristics, the breakdown strength of each specimen by an experiment for AC breakdown and the changes of conductivity by measuring volume resistivity are analyzed. It is considered that the effective content of BTA as charge suppressant additive is about 10[ppm] from the results of AC breakdown and volume resistivity test.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.11
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• pp.1617-1620
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• 2013

The widely-used measurement methods for conductivity of non-magnetic metals are van der Pauw method, Two Point Probe method and Eddy Current method. Among them a more simpler and easier method is the Eddy Current method and an instrument using the method is a Conductivity Meter which can measure a conductivity by contacting its probe on a sample surface. However, conductivity standards are essentially needed to confirm the meter's performance or to calibrate it. In this study, six kinds of the standards which are made of Cu, Al-1, Al-2, brass, Zn and SUS-316 are developed and conductivity ranges for the standards are 2.27 %IACS ~ 101.6 %IACS with measurement uncertainty of less than 0.3 %.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.2
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• pp.49-55
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• 1999

This paper proposes an efficient 2D Finite Element Method(FEM) taking into account the end-ring of three phase squirrel-cage induction motors. The parameters of the squirrel-cage induction motor such as conductivity of secondary conductor have an effect on the characteristics of a motor. Especially, if the characteristic analysis is done without considering the end-ring, the good results can not be obtained. Therefore, we calculated a new resistivity of the secondary conductor including the end-ring's resistance to apply the 2D FEM. Then, the performances of the motors are analyzed by using the new resistivity of secondary conductor which contains the end-ring resistivity. The validity of the proposed method is verified by comparing the numerical results with experimental ones.

• Journal of the Korean institute of surface engineering
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• v.42 no.6
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• pp.267-271
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• 2009

Multicomponent transparent conducting oxide films were deposited on glass substrates at 150 by dual magnetron sputtering of AZO and ITO targets. In the case of mixing a limited amount of ITO (10W), resistivity of TCO films was significantly increased compared to the AZO film; from $3.5{\times}10^{-3}$ to $9.7{\times}10^{-3}{\Omega}{\cdot}cm$. Deterioration of the electrical conductivity is attributed to the decreases in carrier concentration and Hall mobility. Improvement of the conductivity could be obtained for the films prepared with ITO powers larger than 40 W. The lowest resistivity ($\rho$) of $7.3{\times}10^{-4}{\Omega}{\cdot}cm$ was achieved when ITO power was 100 W. Effects of $H_2$ incorporation on the electrical and optical properties of AZO-ITO films were investigated in this work. Addition of small amount of hydrogen resulted in the increase of carrier concentration and the improvement of electrical conductivity. It is apparent that the roughness of AZO-ITO films decreases dramatically after the transition of microstructure from polycrystalline to amorphous phase, which gives practical advantages such as an excellent uniformity of surface and a high etching rate. AZO-ITO films grown at sputtering ambient with hydrogen gas are expected to be applicable to optoelectronic devices such as organic light emitting diodes and flexible displays due to their sufficient electrical and structural properties.

• Journal of the Korean Ceramic Society
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• v.42 no.12 s.283
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• pp.833-841
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• 2005

The oxidation resistance and electrical conductivity of various commercial ferritic stainless steels including STS444 were tested in an air atmosphere at $700^{\circ}C$. Crofer22 developed specially for SOFC interconnect was also examined for the aim of comparing with the test results of STS444. Although STS444 exhibited higher oxidation resistance than Corfer22, the electrical conductivity of the scale formed on Crofer22 was higher, indicating that the resistivity of scale formed on Crofer22 is much lower than that of STS444. To gain a better understanding of the relation between oxidation behavior and electrical conductivity, the oxide scales formed on STS444 and Crofer22 were analyzed in terms of the structure, composition, and phase. Consequently, the influence of alloying elements on electrical conductivity of Fe-Cr alloys was discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1992.05a
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• pp.101-104
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• 1992

In-doped CdS thin films have been deposited at 150$^{\circ}C$ by simultaneous thermal evaporation of CdS and In. Deposition rate and film thickness were 8A/sec and about 1um, respectively. Indium doping concentration of films varied as Indium source temperature from 500$^{\circ}C$ to 700˚. Properties of In-CdS films have been investigatied by measurements of electrical resistivity, Hall effect, X-ray diffraction and optical trasmission spectra. The conductivity of these films was always n-type. The resistivity, carrier concentration, mobility and optical band gap dependence on Indium source temperature are reported. Carrier concentration and mobility of In-CdS films increased with increasing Indium source temperature: then they decreased. The variation of the optical band gap of In-CdS thin films are related to carrier concentration.