• 한국세라믹학회지
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• 제50권3호
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• pp.212-217
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• 2013

Ultra hard TiN coatings were fabricated by DC and ICP (inductively coupled plasma) magnetron sputtering techniques. The effects of ICP power, ranging from 0 to 300 W, on the coating microstructure, crystallographic, and mechanical properties were systematically investigated with FE-SEM, AFM, HR-XRD and nanoindentation. The results show that ICP power has a significant influence on the coating microstructure and mechanical properties of TiN coatings. With an increasing ICP power, the film microstructure evolves from an apparent columnar structure to a highly dense one. Grain sizes of TiN coatings decreased from 12.6 nm to 8.7 nm with an increase of the ICP power. A maximum nanohardness of 67.6 GPa was obtained for the coatings deposited at an ICP power of 300 W. The crystal structure and preferred orientation in the TiN coatings also varied with the ICP power, exerting an effective influence on film nanohardness.

• 한국표면공학회지
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• 제46권2호
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• pp.55-60
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• 2013

Superhard TiN coatings were fabricated by DC and ICP (inductively coupled plasma) assisted magnetron sputtering techniques. The effect of ICP power, ranging from 0 to 300 W, on coating microstructure, preferred orientation mechanical properties were systematically investigated with HR-XRD, SEM, AFM and nanoindentation. The results show that ICP power has a significant influence on coating microstructure and mechanical properties of TiN coatings. With the increasing of ICP power, coating microstructure evolves from the columnar structure of DC process to a highly dense one. Grain sizes of TiN coatings were decreased from 12.6 nm to 8.7 nm with increase of ICP power. The maximum nanohardness of 67.6 GPa was obtained for the coatings deposited at ICP power of 300 W. Preferred orientation in TiN coatings also vary with ICP power, exerting an effective influence on film nanohardness.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.894-895
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• 2006

WC-$10C_o$-0.8VC nanocrystalline powders were sintered by spark plasma sintering (SPS) and hot press sintering (HPS), and the microstructure and properties were compared. Results show that dense WC-$10C_o$-0.8VC can be obtained by SPS in several minutes when the sintering temperature is $>1200^{\circ}C$. Sintered at a temperature of $1300^{\circ}C$ the sample prepared by SPS for 3 minutes has higher density, finer grains and better properties than that prepared by HPS for 60 minutes. SPS can be used to prepare nanocrystalline WC-$10C_o$-0.8VC with improved properties when suitable sintering parametesr are chosen.

• 한국분말재료학회지
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• 제14권3호
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• pp.197-201
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• 2007

Bulk metallic glass (BMG) composite was fabricated by consolidation of milled metallic glass composite powders. The metallic glass composite powder was synthesized by a controlled milling process using the Cu-based metallic glass powder blended with 30 vol% Zr-based metallic glass powders. The milled composite powders showed a layered structure with three metallic phases, which is formed as a result of mechanical milling. By spark plasma sintering of milled metallic glass powders in the supercooled liquid region, a fully dense BMG composite was successfully synthesized.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2002년도 추계학술대회 발표 논문집
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• pp.123-126
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• 2002

For the mold die sticking mechanism, the major explanation is that EMC filler of silica wears die surface roughened, which results in increase of adhesion strength. As big differences in experimental results from semiconductor manufacturers are dependent on EMC models, however, chemisorptions or acid-base interaction is apt to be also functioning as major mechanisms. In this investigation, the plasma source ion implantation (PSII) using $O_2$, $N_2$, and $CF_4$ modifies sample surface to form a new dense layer and improve surface hardness, and change metal surface condition from hydrophilic to hydrophobic and vice versa. Through surface energy quantification by measuring contact angle and surface ion coupling state analysis by Auger, major governing mechanism for sticking issue was figured out to be a complex of mechanical and chemical factors.

• 마이크로전자및패키징학회지
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• 제9권4호
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• pp.31-34
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• 2002

For the mold die sticking mechanism, the major explanation is that the silica as a filler in EMC (epoxy molding compound) wears die surface to be roughened, which results in increase of adhesion strength. As the sticking behavior, however, showed strong dependency on the EMC models based on the experimental results from different semiconductor manufacturers, chemisorption or acid-base interaction is apt to be also functioning as major mechanisms. In this investigation, the plasma source ion implantation (PSII) using $O_2, N_2$, and $CF_4$ modifies sample surface to form a new dense layer and improve surface hardness, and change metal surface condition from hydrophilic to hydrophobic or vice versa. Through surface energy quantification by measuring contact angle and surface ion coupling state analysis by Auger, major governing mechanism for sticking issue was figured out to be a complex of mechanical and chemical factors.

• 한국표면공학회지
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• 제37권5호
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• pp.243-248
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• 2004

A palladium-nikel(Pd-Ni) alloy composite membrane has been fabricated on microporous nickel support formed with nickel powder. Plasma surface treatment process is introduced as pre-treatment process instead of HCI activation. Pd coating layer was prepared by dc magnetron sputtering deposition after $H_2$ plasma surface treatment. Palladium-nickel alloy composite layer had a fairly uniform and dense surface morphology. The membrane was characterized by permeation experiments with hydrogen and nitrogen gases at temperature of 773 K and pressure of 2.2psi. The hydrogen permeance was 6 ml/minㆍ$\textrm{cm}^2$ㆍatm and the selectivity was 120 for hydrogen/nitrogen($H_2$/$N_2$) mixing gases at 773 K.

• Nuclear Engineering and Technology
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• 제53권2호
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• pp.583-591
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• 2021

Various compositions of CeO₂-Ce₃Si₂ (0, 10, 30, 50, and 100 wt%Ce₃Si₂) composites were fabricated using conventional sintering and spark plasma sintering. Lower relative density, enhanced interdiffusion of oxygen and silicon, and silicide agglomerations from the congruent melting of Ce₃Si₂ at 1390 ℃ were only observed from conventionally-sintered pellets. Thermal conductivity of spark plasma sintered CeO₂-Ce₃Si₂ composites was calculated from the measured thermal diffusivity, specific heat, and density, which exhibited dense (>90 %TD) and homogeneous microstructure. The composite with 50 wt%Ce₃Si₂ exhibited 55% higher thermal conductivity than CeO₂ at 500 ℃, and 81% higher at 1000 ℃.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 가을 학술논문 발표대회
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• pp.52-53
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• 2020

The thermal spray coating process is being used to protect the metals and alloys from wear, abrasion, fatigue, tribology, and corrosion failure. Therefore, in the present study, Al and Zn was deposited by plasma arc thermal spray process onto the steel substrate and their performance was assessed. The bond adhesion result shows that Al coating has higher value attributed to compact, dense, and less porous compared to Zn coating which contain defects/pores and uneven morphology assessed by scanning electron microscopy (SEM). Electrochemical results show that the Al coating exhibited higher impedance value compared to Zn in artificial ocean water solution at prolonged exposure periods. However, both coatings show the increment in polarization resistance with exposure periods which reveal that porosity of coatings is filled by the corrosion products.

• 한국재료학회지
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• 제26권5호
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• pp.229-234
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• 2016

In this study, the degree of particle melting in $Y_2O_3$ plasma spraying and its effects on coating characteristics have been investigated in terms of microstructural features, microhardness and scratch resistance. Plasma sprayed $Y_2O_3$ coatings were formed using two different powder feeding systems: a system in which the powder is fed inside the plasma gun and a system in which the powder is fed externally. The internal powder spraying method generated a well-defined lamellae structure that was characterized by a thin porous layer at the splat boundary and microcracks within individual splats. Such micro-defects were generated by the large thermal contraction of splats from fully-molten droplets. The external powder spraying method formed a relatively dense coating with a particulate deposition mode, and the deposition of a higher fraction of partially-melted droplets led to a much reduced number of inter-splat pores and intra-splat microcracks. The microhardness and scratch resistance of the $Y_2O_3$ coatings were improved by external powder spraying; this result was mainly attributed to the reduced number of micro-defects.