윤활접촉하의 탄소(WC/C) 박막의 마멸기구

안효석(Hyo-Sok Ahn),김두인(Doo-In Kim) 한국생산제조학회 2008 한국생산제조시스템학회 학술발표대회 논문집 Vol.2008 No.5

The running-in behaviour of the metal carbon coating (WC/C) has been evaluated with regard to its applicability as wear-resistant coating to key components in engines. Confocal microscopy and scanning electron microscopy were used to observe worn surfaces and the wear scars on the steel balls. Elemental composition of the coating and worn surfaces were characterized using Auger electron spectroscopy. The friction behavior of WC/C coating was comparable to common carbon-based coatings. Thin tribofilm was formed on the worn surface of the steel ball due to material transfer and tribochemical reaction whereas there was no evidence of tribofilm generation on the coating surface. indicating the chemical innertness of WC/C coating.

윤활접촉하의 탄소(WC/C) 박막의 마멸기구

안효석,김두인 한국공작기계학회 2008 한국공작기계학회 춘계학술대회논문집 Vol.2008 No.-

The running-in behaviour of the metal carbon coating (WC/C) has been evaluated with regard to its applicability as wear-resistant coating to key components in engines. Confocal microscopy and scanning electron microscopy were used to observe worn surfaces and the wear scars on the steel balls. Elemental composition of the coating and worn surfaces were characterized using Auger electron spectroscopy. The friction behavior of WC/C coating was comparable to common carbon-based coatings. Thin tribofilm was formed on the worn surface of the steel ball due to material transfer and tribochemical reaction whereas there was no evidence of tribofilm generation on the coating surface. indicating the chemical innertness of WC/C coating.

WC/C 박막의 윤활접촉하의 마멸기구

안효석(Hyo-Sok Ahn),김두인(Doo-In Kim) 한국트라이볼로지학회 2008 한국윤활학회지(윤활학회지) Vol.24 No.6

The running-in behaviour of the metal carbon coating (WC/C) was evaluated with regard to its applicability as wear-resistant coating for key components in engines. Reciprocating wear tests under lubricated condition employing an oscillating friction wear tester were performed to investigate the tribological behaviors of the coatings in ambient environment. Confocal microscopy and scanning electron microscopy were used to observe worn surfaces and the wear scars on the steel balls. Elemental composition of the coating and worn surfaces were characterized using Auger electron spectroscopy. The friction behavior of WC/C coating was comparable to common carbon-based coatings. Thin tribofilm was formed on the worn surface of the steel ball due to material transfer and tribochemical reaction whereas there was no evidence of tribofilm generation on the coating surface. indicating the chemical innertness of WC/C coating.

Investigation of NH4OH on Zircaloy-4 Surfaces Using Electron Emission Spectroscopy

Hye Yoon Jung,Yong-Cheol Kang* 대한화학회 2007 Bulletin of the Korean Chemical Society Vol.28 No.10

The interaction of ammonium hydroxide (NH4OH) with zircaloy-4 (Zry-4) was investigated using X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) methods. In order to study the surface chemistry of NH4OH/Zry-4 system, the binding energies of N1s, O1s and Zr3d electrons were monitored. The N1s peak intensity was remarkably increased by following cycles of Ar+ sputtering of NH4OH dosed Zry-4 surface at room temperature. Because the nitrogen stayed under the subsurface region was diffused out onto the Zry-4 surface after oxygen concentration was decreased. These could be occurred after the surface oxygen was diffused into the bulk or desorbed out from the surface until Ar+ fluence was 6.0 ´ 1016 Ar+/cm2 then the surface was relatively atomic deficient state. The O1s peak intensity was decreased by stepwise Ar+ sputtering. After many cycles of Ar+ sputtering, the peak intensities of Zr3d peaks did not change much but the shape of the peak clearly did change. This implies that the oxidation state of zirconium was changed during stepwise Ar+ sputtering of NH4OH/Zry-4. The Zr3d peak intensity of zirconium nitride (ZrNx) increased as the intensity of N1s (from zirconium nitride) increased but the Zr3d peak intensity of zirconium oxide (ZrOx) decreased due to the depopulation of the oxygen species on the surface region. We also observed that the peak intensity of Zr4+ was nearly same after Ar+ sputtering processes but the peak intensity of metallic zirconium increased compared to that of before the sputtering process was performed.

Surface Phenomena of Deuterized Ethanol Exposed Zircaloy-4 Surfaces

Juyun Park,Se-Won Jung,Mi-Sun Chun,Yong-Cheol Kang 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.6

We report the results of the surface chemistry of deuterized ethanol exposed Zircaloy-4 (Zry-4) surfaces with various amount of C2D5OD exposures at 190 K. This system was examined with Auger electron spectroscopy (AES) and temperature programmed desorption (TPD) techniques. In TPD study, D2 was evolved at two different desorption temperature regions accompanying with broad desorption background. The lower temperature feature at around 520 K showed first-order desorption kinetics. The high temperature desorption peak at around 650 K shifted to lower desorption temperature as the exposure of C2D5OD increased. The Zr(MNV) Auger peak shifted about 2.5 eV from 147 eV to lower electron energy followed by 300 L of C2D5OD dosing. This implies metallic zirconium was oxidized by deuterized ethanol adsorption. After stepwise annealing of the oxidized Zry-4 sample up to 843 K, the shifted Zr(MNV) peak was gradually shifted back to metallic zirconium peak position. After the sample was heated to 843 K, the oxygen content near the Zry-4 surface was recovered to clean surface level. The concentration of carbon, however, was not recovered by annealing the sample.

Structural and Optical Properties of InGaN/GaN Single Quantum Well Grown via MOCVD

최승규,장재민,정우광,김진열,김승대 대한금속·재료학회 2008 ELECTRONIC MATERIALS LETTERS Vol.4 No.2

InGaN/GaN single quantum well (SQW) was grown on (0001) sapphire substrates via metal organic chemical vapor deposition (MOCVD). The InGaN interlayer was deposited at 750°C using trimethylgallium, trimethylindium, and NH3 with flow rates of 17.7 μmol/min, 27.0 μmol/min, and 3.6 slm, respectively, for 60 seconds. The InGaN/GaN SQW was composed of a 2 μm thick GaN buffer layer, a 20 nm thick InGaN interlayer, and a 150 nm thick GaN capping layer. Auger electron spectroscopy (AES) revealed the composition of the InGaN interlayer to be In0.1Ga0.9N. The room temperature photoluminescence (RT-PL) spectrum showed peaks for a GaN buffer layer and an In0.1Ga0.9N interlayer at 362.2 nm (3.41 eV) and 446.6 nm (2.7 eV), respectively. The composition of the InGaN interlayer estimated from the PL peak position agreed well with the value determined by AES.

Surface Phenomena of Deuterized Ethanol Exposed Zircaloy-4 Surfaces

Park, Ju-Yun,Jung, Se-Won,Chun, Mi-Sun,Kang, Yong-Cheol Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.6

We report the results of the surface chemistry of deuterized ethanol exposed Zircaloy-4 (Zry-4) surfaces with various amount of $C_2D_5$OD exposures at 190 K. This system was examined with Auger electron spectroscopy (AES) and temperature programmed desorption (TPD) techniques. In TPD study, $D_2$ was evolved at two different desorption temperature regions accompanying with broad desorption background. The lower temperature feature at around 520 K showed first-order desorption kinetics. The high temperature desorption peak at around 650 K shifted to lower desorption temperature as the exposure of $C_2D_5$OD increased. The Zr(MNV) Auger peak shifted about 2.5 eV from 147 eV to lower electron energy followed by 300 L of $C_2D_5$OD dosing. This implies metallic zirconium was oxidized by deuterized ethanol adsorption. After stepwise annealing of the oxidized Zry-4 sample up to 843 K, the shifted Zr(MNV) peak was gradually shifted back to metallic zirconium peak position. After the sample was heated to 843 K, the oxygen content near the Zry-4 surface was recovered to clean surface level. The concentration of carbon, however, was not recovered by annealing the sample.

열교환 부품용 발열체 형성기술

조남인,김민철 한국반도체디스플레이기술학회 2003 한국반도체장비학회지 Vol.2 No.4

We present a formation technique of thin film heater for heat transfer components. Thin film structures of Cr-Si have been prepared on top of alumina substrates by magnetron sputtering. More samples of Mo thin films were prepared on silicon oxide and silicon nitride substrates by electron beam evaporation technology. The electrical properties of the thin film structures were measured up to the temperature of $500^{\circ}C$. The thickness of the thin films was ranged to about 1 um, and a post annealing up to $900^{\circ}C$ was carried out to achieve more reliable film structures. In measurements of temperature coefficient of resistance (TCR), chrome-rich films show the metallic properties; whereas silicon-rich films do the semiconductor properties. Optimal composition between Cr and Si was obtained as 1 : 2, and there is 20% change or less of surface resistance from room temperature to $500^{\circ}C$. Scanning electron microscopy (SEM) and Auger electron spectroscopy (AES) were used for the material analysis of the thin films.

Structural and Optical Properties of InGaN/GaN Single Quantum Well Grown via MOCVD

( Seung Kyu Choi ),( Jae Min Jang ),( Woo Gwang Jung ),( Jin Yeol Kim ),( Sung Dai Kim ) 대한금속재료학회 ( 구 대한금속학회 ) 2008 ELECTRONIC MATERIALS LETTERS Vol.4 No.2

InGaN/GaN single quantum well (SQW) was grown on (0001) sapphire substrates via metal organic chemical vapor deposition (MOCVD). The InGaN interlayer was deposited at 750℃ using trimethylgallium, trimethylindium, and NH3 with flow rates of 17.7 μmol/min, 27.0 μmol/min, and 3.6 slm, respectively, for 60 seconds. The InGaN/GaN SQW was composed of a 2 μm thick GaN buffer layer, a 20 nm thick InGaN interlayer, and a 150 nm thick GaN capping layer. Auger electron spectroscopy (AES) revealed the composition of the InGaN interlayer to be In0.1Ga0.9N. The room temperature photoluminescence (RT-PL) spectrum showed peaks for a GaN buffer layer and an In0.1Ga0.9N interlayer at 362.2 nm (3.41 eV) and 446.6 nm (2.7 eV), respectively. The composition of the InGaN interlayer estimated from the PL peak position agreed well with the value determined by AES.

Tribological properties of ultra-thin diamond-like carbon coating at various humidity

Pham Duc Cuong,Hyo-Sok Ahn,Choong-Hyun Kim,Doo-in Kim 한국트라이볼로지학회 2002 한국트라이볼로지학회 학술대회 Vol.2002 No.10

This study concerns the tribological behaviors of ultra-thin DLC coating with 3 ㎚ thickness deposited in a mixed gas of argon + 20% hydrogen as a function of humidity. Reciprocating wear tests employing a micro wear tester were performed under various normal loads and relative humidity in air environment. The chemical composition of the original and worn surfaces were studied by Auger electron spectroscopy (AES). It showed that the ultra-thin DLC coating exhibited low friction with enough wear stability at low normal load (0.18 N) and its tribological behavior was strongly dependent on the humidity. The sample surfaces before and after the test were examined using atomic force microscopy (AFM). Capillary force and meniscus areas were discussed in order to explain the influence of humidity on the friction force.