• Journal of Powder Materials
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• v.29 no.4
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• pp.314-319
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• 2022

The effect of the laser beam diameter on the microstructure and hardness of 17-4 PH stainless steel manufactured via the directed energy deposition process is investigated. The pore size and area fraction are much lower using a laser beam diameter of 1.0 mm compared with those observed using a laser beam diameter of 1.8 mm. Additionally, using a relatively larger beam diameter results in pores in the form of incomplete melting. Martensite and retained austenite are observed under both conditions. A smaller width of the weld track and overlapping area are observed in the sample fabricated with a 1.0 mm beam diameter. This difference appears to be mainly caused by the energy density based on the variation in the beam diameter. The sample prepared with a beam diameter of 1.0 mm had a higher hardness near the substrate than that prepared with a 1.8 mm beam diameter, which may be influenced by the degree of melt mixing between the 17-4 PH metal powder and carbon steel substrate.

• Progress in Superconductivity
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• v.12 no.2
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• pp.118-123
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• 2011

The properties of $2^{nd}$ generation high temperature superconducting wire, coated conductor strongly depend on the quality of superconducting oxide layer and property of metal substrate is one of the most important factors affecting the quality of coated conductor. Good mechanical and chemical stability at high temperature are required to maintain the initial integrity during the various process steps required to deposit several layers consisting coated conductor. And substrate need to be nonmagnetic to reduce magnetization loss for ac application. Hastelloy and stainless steel are the most suitable alloys for metal substrate. One of the obstacles in using stainless steel as substrate for coated conductor is its difficulties in making smooth surface inevitable for depositing good IBAD layer. Conventional method involves several steps such as electro polishing, deposition of $Al_2O_3$ and $Y_2O_3$ before IBAD process. Chemical solution deposition method can simplify those steps into one step process having uniformity in large area. In this research, we tried to improve the surface roughness of stainless steel(SUS310). The precursor coating solution was synthesized by using yttrium complex. The viscosity of coating solution and heat treatment condition were optimized for smooth surface. A smooth amorphous $Y_2O_3$ thin film suitable for IBAD process was coated on SUS310 tape. The surface roughness was improved from 40nm to 1.8 nm by 4 coatings. The IBAD-MgO layer deposited on prepared substrate showed good in plane alignment(${\Delta}{\phi}$) of $6.2^{\circ}$.

• Journal of the Microelectronics and Packaging Society
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• v.9 no.1
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• pp.49-52
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• 2002

This study demonstrated the feasibility of tape casting method to fabricate soda borosilicate glass-coated stainless steel electrostatic chucks(ESC) for low temperature semiconductor processes. Glass coating on the stainless steel substrate was 125 $\mu\textrm{m}$ thick. The adhesion of glass coating was found to be excellent such that it was able to withstand temperature cycling to over $300^{\circ}C$ without cracking and delamination. The electrostatic clamping pressure generally followed the theoretical voltage-squared curve except at elevated temperatures and high applied voltages. The deviations at elevated temperatures and high applied voltages are due to increased leakage current as the electrical resistivity of glass coating drops.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.262-263
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• 2005

For mechanical and electrical stability and environment protection, Cu and stainless steel stabilizer is laminated to Ag layer to produce a composite neutral-axis(N-A) architecture in which the YBCO layer is centered between the oxide buffered metallic substrate and stabilizer strip lamination. this architecture allows the wire to meet operational requirements including stresses at cryogenic temperature, winding tensions, mechanical bending requirements thermal and electrical stability under fault conditions. we have experimentally studied mechanical properties of laminated stainless steel stabilizer on YBCO coated conductors. we have laminated YBCO coated conductors by continuous dipping soldering process. we have investigated lamination interface between solder and stabilizer, YBCO coated conductor. we evaluated bonding properties tensile / shear bonding strength, peeling strength laminated YBCO coated conductors.

• Journal of the Microelectronics and Packaging Society
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• v.11 no.4 s.33
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• pp.1-5
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• 2004

A multi-layer flexible substrate is composed of copper(Cu)/polyimide that are known as good electrical conductivity, and low dielectric constant, respectively. In this study. conductor line of $5{\mu}m$-pitch was successfully fabricated without non-uniform pattern shape by electroplating copper and coating polyimide on patterned stainless steel. For multi-layer flexible substrate, via holes were drilled by UV laser and filled with electroplating copper and tin. And then, the PI layer with vias and conductor lines was stripped from stainless steel substrate. The PI layers were laminated at once with careful alignment between layers. Solid state reaction between tin and copper during lamination formed the intermetallic compounds of $Cu_6Sn_5$($\eta$-phase) and $Cu_3Sn$($\epsilon$-Phase) and achieved a complete inter-connection by vertically positioning the plugged via holes on via pad. The via formation process has several advantages; such as better electrical property and lower cost than V type via and paste via.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.11a
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• pp.116-119
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• 2000

The advantage of plasma-sprayed coating is their good resistance against thermal shock due to the porous state of the coated layer with a consequently low Youngs modulus. However, the existence of many pores with a bimodal distribution and a laminar structure in the coating reduces coating strength and oxidation protection of the base metals. In order to counteract these problems, there have been many efforts to obtain dense coatings by spraying under low pressure or vacuum and by controlling particle size and morphology of the spraying materials. The aim of the present study is to survey the effects of the HIP treatment between 1100 and 130$0^{\circ}C$ on plasma-sprayed oxide coating of A1$_2$O$_3$, A1$_2$O$_3$-SiO$_2$on the metal substrate (type C18N10T stainless steel). These effects were characterized by phase identification, Vickers hardness measurement, and tensile test before and after HIPing. These results show that high-pressure treatment has an advantage for improving adhesive strength and Vickers hardness of plasma-sprayed coatings.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.524-524
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• 2006

For decades, the pursuit of volume commercialization of low-power reflective displays with a paper-like look has been an unfulfilled dream. While steady technical progress was made throughout the late 1990s, there were still no volume products incorporating electronic paper displays (EPD) on the market. Now, microencapsulated electrophoretic display technology, also called electronic ink, has moved into volume production with a frontplane laminate (FPL) display component called E Ink Imaging Film™. This film is coated roll to roll on a flexible plastic substrate and integrated into a display module. Today, all-plastic segmented displays are being shipped as well as displays with electronic ink FPL being driven by glass TFT backplanes. A roadmap to active matrix flexible electrophoretic displays is being enabled by rapid technical progress on flexible TFT backplanes by a variety companies. Each of the approaches to these backplanes and flexible active matrix displays has different advantages for the various market segments being pursued including large format flexible displays for e-news and other reader applications, rollable displays for compact readers, and high resolution small format displays up to 400 ppi that can have fully integrated drive electronics to reduce size and drive down costs. Backplane approaches include Si on plastic, organic transistors on plastic, and Si transistors on flexible stainless steel substrate. Progress is also being made on next generation inks, including more reflective inks with higher contrast ratios. A full color 6 inch, 170 pixel per inch (PPI) active matrix display using a newer generation ink has been developed and this will be described and demonstrated. Large format segmented flexible displays will also be described.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.116-119
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• 2000

The advantage of plasma-sprayed coating is their good resistance against thermal shock due to the porous state of the coated layer with a consequently low Youngs modules. However, the existence of many pores with a bimodal distribution and a laminar structure in the coating reduces coating strength and oxidation protection of the base metals. In order to counteract these problems, there have been many efforts to obtain dense coatings by spraying under low pressure or vacuum and by controlling particle size and morphology of the spraying materials. The aim of the present study is to survey the effects of the HIP treatment between 1100 and 130$0^{\circ}C$ on plasma-sprayed oxide coating of A1$_2$O$_3$, A1$_2$O$_3$-SiO$_2$ on the metal substrate (type C18N10T stainless steel). These effects were characterized by phase identification, Vickers hardness measurement, and tensile test before and after HIPing, These results show that high-pressure treatment has an advantage for improving adhesive strength and Vickers hardness of plasma- sprayed coatings.

• Journal of the Korean institute of surface engineering
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• v.29 no.2
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• pp.81-92
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• 1996

The cementless fixation of bone ingrowth by porous coatings on artificial hip joint prostheses are replacing polymethylmethacrylate(PMMA) bone cement fixations. However, the major interests in the field of porous metal coating are environmental corrosivity accelerated by metal ion release, deterioration in the mechanical property of the coating, and the mechanical failure of the coatings as well as the substrate. Therefore, the selection of right materials for coatings and the development of porous coating techniques must be accomplished. Because of the existing problems in Ti and Ti alloys which are used extensively, this study is focused on the plasma spraying technique for coating on super stainless steel substrate. In order to determine the optimum conditions which satisfy the requirement for the porous coatings, under the plasma spraying, we selected the experimental parameters which extensively influenced on the characteristics of the coating through the pre-examination. Spray distance has been selected among 120, 160, and 200mm and primary gas flow rate among 70, 100, and 130 SCFH. Current and secondary gas($H_2$) flow rate was fixed at 400A, and 15 SCFH respectively. To understand the characteristics of the coatings, surface morphology, cross-sectional micro-structure, surface roughness, residual stress, and corrosion resistance were elucidated and the best conditions for the bone ingrowth improvement on artificial hip joint prostheses were found.

• Journal of the Korean Society of Combustion
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• v.7 no.4
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• pp.21-28
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• 2002

Synthesis of carbon nanotubes and nanofibers on a metal substrate by an ethylene fueled inverse diffusion flame was illustrated. Stainless steel plates were used for the catalytic metal substrate. Multi-walled carbon nanotubes and nanofibers with a diameter range of 30-80nm were found on the substrate. The temperature of the substrate played an important role in the formation of carbon nanotubes and nanofibers. The pathway to the nanotubes and nanofibers could be determined by the temperature history of the substrate.