• 한국정밀공학회지
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• 제20권5호
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• pp.189-195
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• 2003

Atomic Force Microscope (AFM) has been widely used in micro/nano-scale studies and applications for. the last few decade. In this work, wear characteristics of silicon-based AFM tip was investigated. AFM tip shape was observed using a high resolution SEM and the wear coefficient was approximately calculated based on Archard's wear equation. It was shown that the wear coefficient of silicon and silicon nitride were in the range of ${10}^{-1}$~${10}^{-3}$ and ${10}^{-3}$~${10}^{-4}$, respectively. Also, the effect of relative humidity and sliding distance on adhesion-induced tip wear was discussed. It was found that the tip wear has more severe for harder test materials. Finally, the probable wear mechanism was analyzed from the adhesive and abrasive interaction point of view.

• International Journal of Precision Engineering and Manufacturing
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• 제5권2호
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• pp.39-45
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• 2004

Atomic Force Microscope (AFM) has been widely used in micro/nano-scale studies and applications for the last few decades. In this work, wear characteristics of silicon-based AFM tip was investigated. AFM tip shape was observed using a high resolution SEM and the wear coefficient was approximately calculated based on Archard's wear equation. It was shown that the wear coefficient of Si and ${Si}_3$$N_4$ tips were in the range of ${10}^{-1}$~${10}^{-3}$and ${10}^{-3}$~${10}^{-4}$, respectively. Also, the effect of relative humidity and sliding distance on adhesion-induced tip wear was investigated. It was found that the tip wear has more severe for harder counter surface materials. Finally, the probable wear mechanism was analyzed from the adhesive and abrasive interaction point of view.

• 한국재료학회지
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• 제17권10호
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• pp.544-547
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• 2007

Human teeth were scratched by the abrasive paper, dropping in hydroxyapatite solution during 1, 2, 3, 4 months. We studied teeth surface change with SEM each months. After 1 months treatment the surface appeared the change. Because of the hydroxyapatite ion exchange mechanism. The scratched surface was recovered by the hydroxyapatite. The results of EDS showed that $Ca^{2+}$ ion and $PO_4^{3-}$ ion were removed from hydroxyapatite solution to scratched teeth surface.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.541-541
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• 2008

반도체 소자가 차세대 초미세 공정 기술 도입의 가속화를 통해 고속화 및 고집적화 되어 감에 따라 나노(Nano) 크기의 회로 선폭 미세화를 극복하고자 최적의 CMP (Chemical Mechanical Polishing) 공정이 요구되어지고 있다. 이처럼 CMP 공정이 반도체 제조 공정에 적용됨으로써 공정 마진 확보에 진일보 하였으나 CMP 장비의 공정 조건, 슬러리의 종류, 연마패드의 종류 등에 의해 CMP 성능이 결정된다. 특히 슬러리는 연마 공정의 성능에 중요한 영향을 미치는 요인이다. 고가의 슬러리가 차지하는 비중이 40% 이상을 넘고 있어 슬러리 원액의 소모량을 줄이기 위한 연구들이 현재 활발히 진행되고 있다. 본 연구에서는 새로운 연마제의 특성을 알아보기 위해 탈이온수(De-ionized water; DIW) 에 $CeO_2$, 연마제를 첨가한 후 분산시간에 따른 연마 특성과 AFM, EDX, XRD, TEM분석을 통해 그 가능성을 알아보았다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.78-78
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• 2007

In semiconductor devices, Cu has been used for the formation of multilevel metal interconnects by the damascene technique. Also lower dielectric constant materials is needed for the below 65 nm technology node. However, the low-k materials has porous structure and they can be easily damaged by high down pressure during conventional CMP. Also, Cu surface are vulnerable to have surface scratches by abrasive particles in CMP slurry. In order to overcome these technical difficulties in CMP, electro-chemical mechanical planarization (ECMP) has been introduced. ECMP uses abrasive free electrolyte, soft pad and low down-force. Especially, electrolyte is an important process factor in ECMP. The purpose of this study was to characterize KOH and $KNO_3$ based electrolytes on electro-chemical mechanical. planarization. Also, the effect of additives such as an organic acid and oxidizer on ECMP behavior was investigated. The removal rate and static etch rate were measured to evaluate the effect of electro chemical reaction.

• Advances in nano research
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• 제12권6호
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• pp.583-592
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• 2022

In this paper, a pulsed picosecond laser dressing method for bronze-bonded diamond wheel is studied systematically and comprehensively. The picosecond laser pulse ablation experiment is carried out, and the ablation thresholds of bronze-bonded and diamond abrasive particle are measured respectively. The results indicate that the single-pulse ablation thresholds of bronze-bonded are 0.89J/cm², 0.24J/cm² during strong/weak ablation stages. And the multi-pulse ablation thresholds of diamond abrasive particle are 1.69J/cm², 0.49J/cm² during strong/weak ablation stages. Obviously, diamond grains have less thermal damage during the process of gentle ablation. The diamond grains of the grinding wheel surface are graphitized during laser dressing. The bronze-bonded is relatively smooth and organizational stability, and the diamond grits have suitable prominent height, which are beneficial to maintain the good grinding performance of dressed bronze-bonded diamond grinding wheels.

• 한국기계가공학회지
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• 제16권5호
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• pp.85-90
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• 2017

Mica-glass ceramics has features such as micro-sized crystals, high strength, chemical resistance, semitransparent optical properties, etc. Due to its superior material properties, mica glass ceramics have increasing applications in dental and medical components, insulation boards, chemical devices, etc. In many applications, especially for dental and medical components, ultra-precise polishing is required. However, it is known to be a very difficult-to-grind material because of its high hardness and brittle properties. Thus, in this study, a newly developed ultra-precise polishing method is applied to obtain nano-level surface roughness of the mica glass ceramics using magnetorheological (MR) fluids and nano abrasives. Nano-sized ceria particles were used for the polishing of the mica glass ceramics. A series of experiments were performed under various polishing conditions, and the results were analyzed. A very fine surface roughness of Ra=6.127 nm could be obtained.

• Corrosion Science and Technology
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• 제6권4호
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• pp.159-163
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• 2007

Micron size Co-alloy 800 (T800) powder is coated on the high temperature, oxidation and corrosion resistant super alloy Inconel 718 substrate by the optimal high velocity oxy-fuel (HVOF) thermal spray coating process developed by this laboratory. For the study of durability improvement of high speed spindle operating without lubricants, friction and sliding wear behaviors of the coatings are investigated both at room and at an elevated temperature of $1000^{\circ}F(538^{\circ}C)$. Friction coefficients, wear traces and wear debris of coatings are drastically reduced compared to those of non-coated surface of Inconel 718 substrate both at room temperature and at $538^{\circ}C$. Friction coefficients and wear traces of both coated and non-coated surfaces are drastically reduced at higher temperature of $538^{\circ}C$ compared with those at room temperature. At high temperature, the brittle oxides such as CoO, $Co_{3}O_{4}$, $MoO_2$ and $MoO_3$ are formed rapidly on the sliding surfaces, and the brittle oxide phases are easily attrited by reciprocating slides at high temperature through oxidation and abrasive wear mechanisms. The brittle solid oxide particles, softens, melts and partial-melts play roles as solid and liquid lubricants reducing friction coefficient and wear. These show that the coating is highly recommendable for the durability improvement coating on the machine component surfaces vulnerable to frictional heat and wear.

• Advances in nano research
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• 제13권1호
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• pp.97-111
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• 2022

In the present article, silica nanoparticles (SNPs) were exploited to improve the tribological and mechanical properties of vinyl ester/glass fiber composites. To the best of our knowledge, there hasn't been any prior study on the wear properties of glass fiber reinforced vinyl ester SiO₂ nanocomposites. The wear resistance is a critical concern in many industries which needs to be managed effectively to reduce high costs. To examine the influence of SNPs on the mechanical properties, seven different weight percentages of vinyl ester/nano-silica composites were initially fabricated. Afterward, based on the tensile testing results of the silica nanocomposites, four wt% of SNPs were selected to fabricate a ternary composite composed of vinyl ester/glass fiber/nano-silica using vacuum-assisted resin transfer molding. At the next stage, the tensile, three-point flexural, Charpy impact, and pin-on-disk wear tests were performed on the ternary composites. The fractured surfaces were analyzed by scanning electron microscopy (SEM) images after conducting previous tests. The most important and interesting result of this study was the development of a nanocomposite that exhibited a 52.2% decrease in the mean coefficient of friction (COF) by augmenting the SNPs, which is beneficial for the fabrication/repair of composite/steel energy pipelines as well as hydraulic and pneumatic pipe systems conveying abrasive materials. Moreover, the weight loss due to wearing the ternary composite containing one wt% of SNPs was significantly reduced by 70%. Such enhanced property of the fabricated nanocomposite may also be an important design factor for marine structures, bridges, and transportation of wind turbine blades.

• Composites Research
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• 제20권5호
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• pp.49-55
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• 2007

반도체 쿼츠 웨이퍼 다이싱용 블레이드는 마이크로/나노 디바이스와 부품을 제조하기 위해 고정밀도의 가공성을 요구한다. 따라서 균일한 마이크로/나노 선폭의 가공을 위해서는 블레이드의 제작 단계에서 균일한 두께와 밀도를 유지하는 것이 중요하다. 기존의 실리콘웨이퍼 가공을 위해서는 금속의 블레이드가 사용되고 있지만 쿼츠 웨이퍼 가공을 위해서는 고분자 복합재가 사용된다. 이러한 복합재는 가공성, 전기전도성, 그리고 적절한 강도와 연성 및 마모저항성이 있어야 한다. 그러나 기존의 건식성형 공정으로는 균일성을 유지하기 위해 많은 공정과 비용이 소비되고 있다. 본 연구에서는 도전성 나노 세라믹스 분말, 연마재 세라믹스 분말에 열경화성 수지, 전도성 고분자를 혼합한 복합재 분말을 습식성형 공정에 의해 제조, 평가하는 연구를 수행하였다. 먼저 복합재 분말을 액상과 혼합하여 블레이드를 제작하였으며, 액상의 종류, 액상 건조공정의 영향을 고찰하였다. 평가는 마이크로미터 측정기와 현미경을 이용하여 두께를 측정하였다. 두께편차와 기공률, 밀도, 경도, 등의 특성을 비교, 평가하였다. 그 결과 습식성형에 의해 블레이드의 두께편차를 감소시킬 수 있었으며, 경도 등의 특성을 향상시킬 수 있었다.