• Transactions on Electrical and Electronic Materials
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• v.12 no.4
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• pp.135-139
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• 2011

In an effort to develop new electrical insulation materials, four different kinds of organically modified layered silicate were incorporated into an epoxy matrix to prepare nanocomposites for electrical insulation. Five wt% of organically modified layered silicates were processed in a planetary centrifugal mixer in an epoxy matrix, and the thermal, mechanical, and electrical properties of the cured epoxy/layered silicate were investigated. The morphology of the nanoscale silicate dispersed in the epoxy matrix was observed using transmission electron microscopy, and the interlayer distance was measured by wide-angle X-ray scattering diffraction analysis.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.3
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• pp.87-95
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• 1992

The electrical characteristics of Al/TaS12TOS15T/SiOS12T/Si metal insulator-semiconductor (MIS) capacitors were studied. Tantalum pentoxide thin films on SiOS12T/p-Si substrate have been prepared by thermal oxidation at 450-$600^{\circ}C$ of sputter deposited tantalum films. Composition and structures of the tantalum oxide films were examined by AES and XRD. From the C-V analysis, dielectric constant of TaS12TOS15T which were oxidized at 55$0^{\circ}C$ for 1h in OS12T were 18-23, the value depending on the oxidation and annealing temperature. The leakage current density was found to be about 10S0-10T-10S0-9T A/cmS02T at an applied electric field of 1 MV/cm. The dielectric breakdown strength of the tantalum oxide films annealed at 100$0^{\circ}C$ were in the range from 2.5MV/cm to 2.8 MV/cm.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.542-545
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• 1987

THE ELECTRICAL CHARACTERISTICS Of RAPID THERMAL OXIDES AND NITRIDED OXIDES HAVE BEEN INVESTIGATED. R.T.OXIDE FILMS HAVE BEEN PREPARED BY ONLY R.T. OXIDATION OR R.T.OXIDATION AND SUBSEQUENT R.T.ANNEAL. NITRIDED OXIDE FILMS HAVE BEEN PREPARED BY R.T.OXIDATION AND SUBSEQUENT R.T.NITRIDATION.AND CONVENTIONAL OXIDES ALSO HAVE BEEN PREPARED TO COMPARE WITH R.T.P OXIDES. R.T.ANNEALED OXIDES SHOW EXCELLENT BREAKDOWN FIELD. LEAKAGE CURRENT AND TDDB CHARACTERISTICS. ALSO, CAPACITANCE Of R.T NITRIDED OXIDES ARE SUPERIOR BY 10% TO CONVENTIONAL OXIDES, BUT TDDB CHARACTERISTIC ARE POORER THAN OXIDE FILMS.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.687-690
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• 2000

This paper provides the result of the analysis of the lightening arresters which were disconnected from the power line due to the overvoltage having high current. The effect of thermal runaway on the microstructures of lightening arrester's block was intensively investigated. The chance of the microstructures of the blocks was limited only on the breakdown paths and near them. Also even though a disconnector was disconnected from the arrester, some of the lightening arrester were showed normal characteristics.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.226-227
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• 2007

Nanostructured materials are attracting increased interest and application. Exciting perspectives may be offered by electrical insulation. Epoxy/Organoclay nanocomposites may find new and upgraded applications in the electrical industry, replacing conventional insulation to provide improved performances in electric power apparatus, e.g, high voltage motor/generator stator winding insulation, dry mold transformer, etc. This paper shows that electrical and thermal properties of epoxy/organoclay nanocomposites insulating materials for dsc, dielectric constant, I-V characteristics, breakdown volatge, can improve significantly with respect to the basic, virgin materials.

• Bulletin of the Korean Chemical Society
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• v.21 no.1
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• pp.69-74
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• 2000

Applicability of Thermal field flow fractionation (ThFFF) was investigated for the analysis of masticated natural rubber (NR) adhesives produced bya hot melt mastication process. An optimum ThFFF condition for NR analysis was found by using tetrahydrofuran (THF) as a solvent/carrier and a field-programming. Low flowrate (0.3 mL/min) was used to avoid stopping the flow for the sample relaxation. Measured molecular weight distribution was used to monitor degradation of rubber during the mastication process. Rubber samples collected at three different stages of the mastication process and were analyzed by ThFFF. It was found that in an anaerobic process rubber degradation occurs at the resin-mixing (compounding) zone as well as in the initial break-down zone, while in an aerobic process most of degradation occurs at the initial breakdown zone. It was also found that E-beam radiation on NR causes a slight increase in the NR molecular weight due to the formation of a branched structure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.4
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• pp.198-202
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• 2018

In this work, we have investigated the effect of a 30-min thermal anneal at $550^{\circ}C$ on the electrical characteristics of neutron-irradiated 4H-SiC MOSFETs. Thermal annealing can recover the on/off characteristics of neutron-irradiated 4H-SiC MOSFETs. After thermal annealing, the interface-trap density decreased and the effective mobility increased in terms of the on-characteristics. This finding could be due to the improvement of the interfacial state from thermal annealing and the reduction in Coulomb scattering due to the reduction in interface traps. Additionally, in terms of the off-characteristics, the thermal annealing resulted in the recovery of the breakdown voltage and leakage current. After the thermal annealing, the number of positive trapped charges at the MOSFET interface was decreased.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.10
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• pp.106-112
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• 1990

The progress of oxidation of a porous silicon layer(PSL) was studied by examining the temperature dependence of the oxidation and the infrared absorption spectra. Thick OPSL(oxidized porous silicon layer). which has the same properties as thermal $SiO_{2}$ of bulk silicon, is formed in a short time by two steps wet oxidation of PSL at $700^{\circ}C$, 1 hr and $1100^{\circ}C$, 1 hr. Etching rate, breakdown strength of the OPSL are strongly dependent on the oxidation temperature, oxidation atmosphere. And its breakdown field was ${1\MV/cm^-2}$ MV/cm The oxide film stress was determined through curvature measurement using a dial gauge. During oxidation at temperature above $1000^{\circ}C$ in dry $O_{2}$, stress on the order of ${10^9}\dyne/{cm^2}{-10^10}\dyne/{cm^2}$ are generated in the OPSL.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.2
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• pp.1-13
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• 2020

The characterization of aging of the pyrotechnic device is conducted thermally, chemically, and spectroscopically. The device is comprised of two parts: (i) igniter composed of Zr and (ii) pyrotechnic delay composed of ZrNi alloy. The thermally induced chemical reaction is identified through Differential Scanning Calorimetry (DSC) and Thermogravimetry Analysis (TGA). The peak deconvolution of the themo-chemical data is used to estimate the enthalpy change of each metallic fuel component. Laser Induced Breakdown Spectroscopy (LIBS) and X-ray Photoelectron Spectroscopy (XPS) are used for chemical species analysis. The decomposition of oxidants by moisture significantly affected the fuel aging, and the formation of oxide film and metal oxide on the fuel surface gave rise to the thermal energy decrease.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1909-1911
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• 2004

It is caused that insulation paper, which had got a lot of thermal stress by over-load after installation, should have been deteriorated in electrical and mechanical characteristics. Beside, insulation material is decreased the insulating property and accelerated aging of them in case of dielectric loss when transformers are manufactured with some moisture or transformers would have been them because of moisture-permeation, Therefore, in this study we experienced the influence of moisture content in case of the thermal aged insulation paper. we have measured tan ${\delta}$ and breakdown voltage in the ratio of paper' moisture content before the aging and then taken the same tests again after insulation paper thermally accelerating-aged. There is a purpose to gain data for a life-design and to establish aging mechanism in order to continuously study life expectancy of the insulation paper.