• 한국표면공학회지
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• 제42권4호
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• pp.173-178
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• 2009

DLC film was synthesized on plastic injection mold(SKD11, $30\;mm\;{\times}\;19\;mm\;{\times}\;0.5\;mm$) and Si(100) wafer for 2 h at $130^{\circ}C$ under 6 mTorr using hybrid method of rf sputtering and ion source. The obtained film was analysed by Raman spectroscopy, AFM, TEM, Nano indenter and scratch tester, etc. The film was defined as an amorphous phase. In the Raman spectrum, broad peak of $sp^2$-bonded carbon attributed to graphite at $1550\;cm^{-1}$ were observed, and the ratio of ID($sp^3$ diamond intensity)/IG($sp^2$ graphite intensity) was approximately 0.54. The adhesion of DLC film was more than 80 N with scratch tester when $0.2\;{\mu}m$ thickness Cr was coated as interlayer. The micro-hardness was distributed at 35~37 GPa. The friction coefficient was 0.02~0.07, and surface roughness(Ra) was 0.34~1.64 nm. The lifetime of DLC coated plastic injection mold using as a connector part in computer was more than 2 times of non-coated mold.

• 한국표면공학회지
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• 제54권6호
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• pp.357-364
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• 2021

In this study, DLC films deposited by PECVD were evaluated to the properties of super-hydrophobic by CF₄ treatment. The structure of DLC films were confirmed by Raman Spectra whether or not mixed sp³ (like diamond) peak and sp² (like graphite) peak. And the hydrogen contents in the DLC films (F-DLC) were measured by RBS analysis. In addition, DLC films were analyzed by scratch test for adhesion, nano-indentation for hardness and tribo-meter of Ball-on-disc type for friction coefficient. In the result of analysis, DLC films had traditional structure regardless of variation of hardness at constant conditions. Also adhesion of DLC film was increased as higher material hardness. Otherwise, friction coefficient was increased as lower material hardness. The DLC films were treated by CF₄ plasma treatment to enhance the properties of super-hydrophobic. And the DLC films were measured by ESEM(Enviromental Scanning Electron Microscope) for water condensation.

• 전기학회논문지
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• 제67권10호
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• pp.1375-1381
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• 2018

In this paper, we studied coatings of the DLC thin film for improving loosening torque of dental implant screw. We used a filtered arc ion plating process which can realize the most dense DLC layer by coating the DLC thin film on the surface of the dental abutment screw. It showed both hardness comparable to diamond and low friction coefficient similar to graphite, and to improve the loosening phenomenon by increasing the screw tightening force Cr/CrN, Ti/TiN or Ti/TiN/Cr/CrN buffer layers were deposited for 5 to 10 minutes to improve the adhesion of the DLC thin film to the surface of the Ti (Gr.5), and then the DLC thin film was coated for about 15 minutes. As a result, the Cr/CrN buffer layer exhibited the highest hardness of 29.7 GPa, the adhesion of 18.62N on average, and a very low coefficient of friction of less than 0.2 as a whole. And we measured loosening torque after one million times with masticatory movement simulator. As a result, the values of the coated screw loosening torque were clearly higher than those of the uncoated screw. From this, it was found that the DLC coating was effective methods improving the loosening torque. In addition, it was confirmed that the cytotoxicity test and cell adhesion test showed high biocompatibility.

• 한국진공학회지
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• 제20권5호
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• pp.333-338
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• 2011

본 연구에서는 전자석 코일 마그네트론 소스를 가지는 비대칭 마그네트론 스퍼터링 장치를 이용하여 보호 코팅 소재로 사용되어지는 비정질 탄소박막을 제작하였다. 내부 전자석 코일의 전류를 고정하고 외부 전자석 코일의 전류를 다양하게 변화시켜 탄소 박막을 제작하였고, 제작되어진 박막들의 경도, 마찰계수, 접착력, 표면 거칠기 등의 트라이볼로지 특성들을 측정하였고, 라만과 HRTEM을 이용하여 구조적 특성을 평가하였으며, 이들 상호간에 관계를 규명하였다. 결과로서, 제작되어진 탄소박막의 경도, 마찰계수, 접착 특성은 외부 전자석 코일 전류가 증가함에 따라 향상되었으며, 이러한 결과는 박막내에 결합력이 강한 $sp^2$ 결합과 클러스터의 형성과 관련된다. 전자석 코일 전류의 증가는 전자와 이온 밀도의 증가시키고, 기판에서 이온의 충돌의 증가와 기판온도 향상을 야기한다. 이러한 현상의 박막내에 증가되어진 $sp^2$ 결합과 클러스터들의 형성은 탄소박막의 트라이볼로지 특성 향상에 기여하였다.

• 농업과학연구
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• 제44권4호
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• pp.487-494
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• 2017

Spinosad and spinetoram are widely used insecticides for the control of lepidopteran larvae, leaf miners, and thrips; however, they might also have low toxicity toward beneficial insects like bees. Because these pesticides are easily photolyzed by ultraviolet radiation, the QuEChERS method, with its simple pretreatment procedure, is often used for analyzing residues of spinosad and spinetoram. The present study performed a residue analysis using a modified QuEChERS method by pretreating with ammonium salt. The limit of detection (LOD) of the modified method was 0.05 mg/kg and the limit of quantification (LOQ) was 0.25 mg/kg. The coefficient of determination ($R^2$) for the calibration curve was 0.999. Also, we examined any change in the adhesion of spinosad and spinetoram on the plants depending on a spray volume. The adhesion was approximately 70% when the spray volume was increased from 60 L to 120 L per 10 a whereas the adhesion was approximately 37% when the spray volume was increased from 125 L to 250 L. This showed that the amount of adhesion decreased with the higher spray volume. The efficacy result of spinetoram was that over 90% of Frankliniella occidentalis was controlled with the application volume of 125 L per 10 a. Therefore, the result of this study indicates that control of insects is effective and sufficient with a spray volume of 125 L per 10 a in paprika cultivation facilities.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2004년도 학술대회지
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• pp.90-98
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• 2004

Nano/micro-scale studies on friction properties were conducted on Si (100) and three self-assembled monolayers (SAMs) (PFOTC, DMDM, DPDM) coated on Si-wafer by chemical vapor deposition technique. Experiments were conducted at ambient temperature $(24{\pm}1^{\circ}C)$ and humidity $(45{\pm}5\%)$. Nano-friction was evaluated using Atomic Force Microscopy (AFM) in the range of 0-40nN normal loads. In both Si-wafer and SAMs, friction increased linearly as a function of applied normal load. Results showed that friction was affected by the inherent adhesion in Si-wafer, and in the case of SAMs the physical/chemical structures had a major influence. Coefficient of friction of these test samples was also evaluated at the micro-scale using a micro-tribotester. It was observed that SAMs had superior frictional property due to their low interfacial energies. In order to study of the effect of contact area on friction coefficient at the micro-scale, friction was measured for Si-wafer and DPDM against Soda Lime balls (Duke Scientific Corporation) of different radii 0.25 mm, 0.5 mm and 1 mm at different applied normal loads $(1500,\;3000\;and\;4800{\mu}N)$. Results showed that Si-wafer had higher friction coefficient than DPDM. Furthermore, unlike that in the case of DPDM, friction was severely influenced by wear in the case of Si-wafer. SEM evidences showed that solid-solid adhesion to be the wear mechanism in Si-wafer.

• KSTLE International Journal
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• 제5권2호
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• pp.37-43
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• 2004

Abstract : Nano/micro-scale friction properties were investigated on Si (100) and three self-assembled monolayers (SAMs) (PFOTC, DMDM, DPDM) coated on Si-wafer by chemical vapor deposition technique. Experiments were conducted at ambient temperature(24$pm$1$circ$C) and humidity(45$pm$5%). Friction at nano-scale was measured using Atomic Force Microscopy (AFM) in the range of 0-40nN normal loads. In both Si-wafer and SAMs, friction increased linearly as a function of applied normal load. Results showed that friction was affected by the inherent adhesion in Ssi-wafer, and in the case of SAMs the physical/chemical structures had a major influence. Coefficient of friction of these test samples at the micro-scale was also energies. In order to study the effect of contact area on coefficient of friction at the micro-scale, friction was measured for Si-wafer and DPDM against Soda Lime balls (Duke Scientiffic Corporation) of different radii (0.25 mm, 0.5 mm and 1 mm) at different applied normal loads (1500, 3000 and 4800 mN). Results showed that Si-wafer had higher coefficient of friction than DPDM. Further, unlike that in the case of DPDM, friction in Si-wafer was severely influenced by its wear. SEM evidences showed that solid-solid adhesion was the wear mechanism in Si-wafer.

• 마이크로전자및패키징학회지
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• 제26권4호
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• pp.101-105
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• 2019

칩 패키지에는 생산 공정 및 운송, 보관 과정에서 발생하는 외부 환경 변화로부터 인쇄 회로 기판(printed circuit board, PCB)을 보호하기 위해 에폭시 몰딩(epoxy molding compound, EMC)이 사용된다. PCB와 EMC의 접합 신뢰성은 제품의 품질 및 수명에 중요한 요소이며 이를 보증하기 위해 제품 설계 및 생산 단계에서 그 접합 에너지를 정밀하게 측정하고, 이에 영향을 끼치는 요소를 통제하여 공정을 최적화 시켜야 한다. 본 논문은 이중 외팔보(double cantilever beam, DCB) 시험을 이용하여 휨(warpage)이 있는 칩 패키지의 EMC와 PCB의 계면 접합 에너지를 측정하고 보정하는 방법에 대해 소개한다. DCB 시험법은 이종 재료의 계면 접합 에너지를 측정하는 전통적인 방법이며 정밀한 접합 에너지 측정을 위해 평평한 기판이 필수적이다. 그러나 칩 패키지는 내부 구성 요소들의 열팽창 계수 차이로 인해 휨이 발생하기 때문에 평평한 기판을 제작하여 정밀한 접합 에너지를 측정하는데 어려움이 있다. 이를 극복하고자 본 연구에서는 휨이 있는 칩 패키지로 DCB 시험법을 위한 시편을 제작하고, 기판의 복원력을 보정하여 접합 에너지를 계산하였다. 보정된 접합에너지는 동일 조건에서 제작된 칩 패키지 중 휨이 없는 시편을 선별하여 측정한 접합 에너지와 비교, 검증하였다.

• 한국군사과학기술학회지
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• 제11권2호
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• pp.109-115
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• 2008

A Plastic Bonded Explosive(PBX) is mainly composed of nitramine explosive and polymer binder. The great number of serious applications of PBX requires the good adhesion between nitramine crystals and binder, which depends on the surface characteristics of a filler and binder. In the pursuit of the better design to achieve the enhanced adhesion, profound knowledge of the surface and interfacial characteristics of explosive and binder should be exploited. In this study, the influences of physicochemical properties between RDX and binders such as interfacial tension($\gamma_{SL}$), latent heat($Q_m$), and density($\rho$) on impact sensitivity of PBX were investigated. As experimental results, the major contribution factor to impact sensitivity of PBX was the interfacial tension, compare with other surface properties. The correlation coefficient of $H_{50}$ versus $\gamma_{SL}$ is 0.9932 when a polynomial regression method was used.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 추계학술대회 논문집
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• pp.250-253
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• 2009

In this study, the friction test was performed to find friction characteristics of advanced high strength steel (AHSS) sheets and the multiple regression method was employed to obtain friction models. The friction coefficients associated with the lubricant viscosity, drawing speed, and blank holding pressure are measured. Differently from GA steel sheets, the effects of the lubricant viscosity and pulling speed are a little, which are explained by a theory of adhesion and wear as well as a deformation of friction surface. In addition, the effects of friction parameters are numerically represented by friction regression models.