• Journal of Power System Engineering
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• v.9 no.4
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• pp.90-95
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• 2005

The wire-arc process is a low-cost thermal spray method simply utilizes electrical energy to melt the feedstock wire. It is more userful for field applications, especially to coat large surface area. In this paper, a special Fe-based alloy coatings by using the wire-arc process were developed. Nanoscale composite coatings were achieved either during spraying or through a post heat treatment. As-sprayed Fe-based alloy coatings had been an amorphous matrix structure, after heating to $700^{\circ}C$ for 10 minutes a solid state transformation occurred in the some fraction of amorphous matrix which resulted in the formation of nanostructured recrystallized phase. Scanning electron microscopy (SEM) and field emotional scanning electron microscope(FE-SEM) were applied to analyze the microstructure of the coatings. Additionally hardness and bend resistance of the Fe-based alloy coatings were examined, and these results were compared with those of partially stabilized zirconia(PSZ) coatings by using the plasma spray process.

• Applied Chemistry for Engineering
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• v.4 no.2
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• pp.264-272
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• 1993

Current research aimed at investigating of heat-resistance of magnet wire to endow miniaturizing electronic equipment with a high efficiency or reliability. Thermal stability of magnet wire has a close relationship with physical properties of polymeric coating that is formed from enamel varnish. Design of heat-resistant enamel varnish and coating technology of varnish solution were briefly described. Some factors which have a thermal effect on wire were discussed through the evaluation method of the wire properties.

• Journal of the Korean GEO-environmental Society
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• v.23 no.1
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• pp.31-37
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• 2022

This study is focused on developing a technology to prevent high-strength wire net from expanding damage due to insufficient performance of the existing PVC coating net. For the test method, reference was made to ISO 17746, an international standard. In addition, as a result of referring to the test criteria, a wire net was fabricated with a width of 1,000 mm or more a size of 1 m² sample. load-displacement curve of the test results was compared to analyze how much performance was improved compared to the existing PVC coating net.

• Journal of the Korean institute of surface engineering
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• v.43 no.3
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• pp.132-141
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• 2010

NiTi alloy has been used for orthodontic wire due to good mechanical properties, such as elastic strength and frictional resistance, combined with a high resistance to corrosion. Recently, these wire were coated by polymer and ceramic materials for aesthetics. The purpose of this study was to investigate surface characteristics of polymer coated NiTi alloy wire for orthodontics using various instruments. Wires (round type and rectangular type) were used, respectively, for experiment. Polymer coating was carried out for wire. Specimen was investigated with field emission scanning electron microscopy(FE-SEM), energy dispersive x-ray spectroscopy(EDS) and atomic force microscopy(AFM). The phase transformation of non-coated NiTi wire from martensite to austenite occurred at the range of $14{\sim}15^{\circ}C$, in the case of coated wire, it occurred at the range of $16{\sim}18^{\circ}C$. Polymer coating on NiTi wire surface decreased the surface defects such as scratch which was formed at severe machined surface. From the AFM results, the average surface roughness of non-coated and coated NiTi wire was 13.1 nm, and 224.5 nm, respectively. From convetional surface roughness test, the average surface roughness of non-coated and coated NiTi wire was $0.046{\mu}m$, and $0.718{\mu}m$, respectively.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.3
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• pp.107-114
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• 2016

Terra Alba Wallpaper was manufactured by coating inorganic terra alba paint on white base paper, and the surface of the coated layers were microscopically observed. Eco Terra Alba used the functional wall paper in this study was prepared by mixing inorganic Terra Alba and calcium carbonate. Terra Alba showed particle shape. The concentration of inorganic components, pH, and the viscosity of the coating solution were 92.0%, 7.82, 1286 cPs, respectively. The bar coater whit No 3 wire resulted in the least thickness of wet coating layer and coating thickness such $22.5{\mu}m$ with covered all the surface. Bar coater with No. 12 wire leaded to $48.4{\mu}m$ thickness. The coating layers above $43{\mu}m$ thickness showed the cracks on the wall paper surface after coating.

• Journal of the Korean GEO-environmental Society
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• v.24 no.2
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• pp.25-30
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• 2023

The high-strength rockfall net developed in this study is to replace the fallout prevention net method using PVC coating net made of core wire thickness 3.2 mm and tensile strength 290-540 MPa class steel wire. General PVC coating net have low performance, and in the event of falling rocks or surface loss, they cannot withstand the load and are torn, which rather adds to the damage. Developed rockfall net was manufactured using steel wires with a core wire thickness of 2.8 to 3.2 mm and a tensile strength of 1,000 to 2,000 MPa. Test method was referred to the international standard Steel wire rope net panels and rolls-Definitions and specifications (ISO 17746:2016), and was conducted in accordance with the provisions of the punching test. Through indoor punching tests, the load-displacement curves of the general PVC coating network and the developed high-strength capture net (1,000 and 2,000 MPa) were compared, and the maximum Pull-out load was analyzed to be improved by 324.47% (2,000 MPa high-strength net).

• Bulletin of the Korean Chemical Society
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• v.35 no.1
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• pp.211-217
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• 2014

A new needle-based device for headspace wire coated in-needle microextraction (HS-WC-INME) was fabricated using a nichrome wire coated with poly(ethylene glycol) (PEG) and poly(dimethylsiloxane) (PDMS) mixture. The proposed needle device was applied for the determination of volatile compounds in lavender and lavandin essential oils by gas chromatography. Fundamental parameters such as needle design, conditions of extraction and desorption were optimized along with the validation of the extraction and desorption efficiency. The optimal conditions were 30 min extraction at $50^{\circ}C$ and 2 min desorption at $240^{\circ}C$. The calibration curves showed good linearity with the suitable values of the coefficients of determination ($r^2$) greater than 0.99. The limits of detection for linalyl acetate, ${\beta}$-caryophyllene, linalool and (+)-limonene were 7.15, 9.04, 10.79 and 22.26 ng, respectively. Analytical recoveries were acceptable in the test samples, varying from 86.7% to 108.0%. The values of relative standard deviations for run to run showed range less than 0.9% while 3.9% through 7.2% for needle to needle. The proposed PEG-PDMS coating could be more suitable than PDMS coating to extract particular polar groups such as alcohols.

• Journal of the Korean Society for Heat Treatment
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• v.25 no.1
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• pp.1-5
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• 2012

The purpose of this study is to prepare a high strength fiberglass reinforced metal. Aluminum covering was carried out over carbon materials such as carbon fiber in order to increase their wettability to molten metals such as aluminum. A sputtering apparatus with a cylindrical target was fabricated to carry out the covering. Sputtering was caused by glow discharge between the target and the two anode plates attached to its top and bottom. As the substrate for preliminary test, a thin carbon wire was used instead of carbon fiber, and the wire was placed at the central axis of the target. Aluminium coating was formed on the whole surface of the substrate. The formation rate and structure of coating were varied by controlling the electrical potential of substrate. When the substrate was electrically isolated, coating with columnar structure was formed with a formation rate of $15{\mu}m/hr$. In case of grounded substrate, coating with amorphous structure was formed with a formation rate of $7{\mu}m/hr$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.151-151
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• 2009

A enameled wire may have better corona-resistance when its coating material contains nano-sized inorganic particles. However, industrial applications are still limited because an aggregation between nanofillers may happen during coating processes. In this study we use a novel scheme of surface modification with silane on silica nanoparticles using sonochemical reaction where composition and surface density of silanes can be controlled in order to reduce particle-particle attractive interaction. Functionalized nanoparticles are evenly dispersed in the matrix confirmed by SEM and energy dispersive x-ray analysis. Dielectric strength and thermal resistance of the nanocomposite wires are improved while flexibility of the wire maintains.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.7
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• pp.1684-1690
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• 1995

A large time asymptotic solution for an unsteady heat conduction problem of a coated hot wire thermal conductivity measurement process was theoretically found. The solution revealed that the slope of wire temperature versus logarthmic time, which is used to evaluate the thermal conductivity, remains unchanged for large values of time even if a layer of coating is present on the hot wire. The significance of this result is that the thermal conductivity of an electrically conductive fluid can be measured with a coated hot wire using the same conversion relation as for a bare wire.