• 제목/요약/키워드: surface textured

검색결과 297건 처리시간 0.025초

표면 구조 변화에 따른 응착과 마찰 특성에 관한 연구 (A Study on the Characteristics of Stiction and Friction of Texture Surface)

  • 양지철;김대은
    • 한국정밀공학회지
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    • 제19권7호
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    • pp.51-58
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    • 2002
  • In this paper, the characteristics of silicon wafer surface which is textured by KOH anisotropic etching method and mechanical polishing are investigated from the viewpoint of stiction and friction. It was found that the characteristics of stiction and friction of each textured surface are dependent on the contact area characterized by surface parameters such as bearing length ratio and peak count. To find the mechanism of the variation of stiction and friction in textured surface, OTS SAM coated wafer was used. In this case, the variation of stiction and friction was diminished, Therefore, it is concluded that the reason of variation of stiction and friction on textured surface is mainly caused by capillary which in turn is affected by the surface topography

비등점의 가열 표면에서 나노유체 액적의 증발 특성 (Characteristics for Nanofluid Droplet Evaporation on Heated Surface at Boiling Temperature of Base Liquid)

  • 김대윤;정정열;이성혁
    • 한국분무공학회지
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    • 제20권4호
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    • pp.236-240
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    • 2015
  • This study aims to experimentally investigate the evaporation characteristics of nanofluid droplet on heated surface at boiling temperature of DI-water. In particular, textured surface was used to examine the effect of wettability on evaporation. At the initial stage of evaporation process, dynamic contact angle (DCA) of nanofluid droplet with 0.01 vol.% concentration on textured surface rapidly increased over its equilibrium contact angle by generated large bubble inside the droplet due to lower wettability. However, contact angle of nanofluid droplet with higher concentration on textured surface decreased with surface tension. In addition, total evaporation time of droplet on textured surface was considerably delayed due to reduction of contact area between droplet and solid surface. Thus, evaporation characteristics were highly affected by the nanofluid concentration and surface wettability.

친수성 마이크로 기둥 구조 표면에서의 표면 지형적 특성에 따른 퍼짐성 현상에 대한 실험적 연구 (Experimental study of spreading phenomena on hydrophilic micro-textured surfaces depending on surface geometrical features)

  • 장문영;박세현;유동인
    • 한국가시화정보학회지
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    • 제16권3호
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    • pp.35-39
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    • 2018
  • In multiphase systems, surface wettability is one of dominant design parameters to enhance system performance. Since surface wettability can be maximized and minimized with micro-textured surfaces, therefore micro-textured surfaces are widely countered in various research and engineering fields. In this study, for better understanding of micrometer scaled surface wettability, spreading phenomena is experimentally investigated on the hydrophilic micro-textured surfaces. By photolithography and conventional dry etching method, there are prepared the surfaces with uniformly arrayed micro-pillars. The interfacial motions of a water droplet on the test sections are visualized by high speed camera in top view. On the basis of visualization data, it is analyzed the relation between dynamic coefficient and geometrical features on micro-textured surfaces.

Surface Texturing for Low Friction Mechanical Components

  • Iqbal, K. Y. Mohd;Segu, D. Z.;Pyung, H.;Kim, J. H.;Kim, S. S.
    • Tribology and Lubricants
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    • 제31권6호
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    • pp.287-293
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    • 2015
  • Laser surface texturing (LST), a surface engineering modification, has been considered as one of the new processes used to improve tribological characteristics of materials by creating artificially patterned microstructure on the contact surface of mechanical components. In LST technology, the laser is optimized to obtain or manufacture the dimples with maximum precision. The micro-dimples reduce the coefficients of friction and also improve the wear resistance of materials. This study investigates the effect of dimple density is investigated. For this purpose, a ball-on-disc type tester is used with AISI 52100 bearing steel as the test material. Discs are textured with a 5% and 10% dimple density. Experimental work is performed with normal loads of 5 N, 10 N, and 15 N under a fixed speed of 150 rpm at room temperature. The effect of the textured surface is compared to that of the untextured one. Experimental results show that the textured surface yields lower friction coefficients compared to those of untextured surfaces. Specifically, the 10% dimple density textured surface shows better friction reduction behavior than the 5% dimple density textured sample, and has an 18% improvement in friction reduction compared with the untextured samples. Microscopic observation using a scanning electron microscope (SEM) shows that the major friction mechanisms of the AISI 52100 bearing steel are adhesion, plastic deformation, and ploughing.

Plasma Textured Glass Surface Morphologies for Amorphous Silicon Thin Film Solar Cells-A review

  • Hussain, Shahzada Qamar;Balaji, Nagarajan;Kim, Sunbo;Raja, ayapal;Ahn, Shihyun;Park, Hyeongsik;Le, Anh Huy Tuan;Kang, Junyoung;Yi, Junsin;Razaq, Aamir
    • Transactions on Electrical and Electronic Materials
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    • 제17권2호
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    • pp.98-103
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    • 2016
  • The surface morphology of the front transparent conductive oxide (TCO) films plays a vital role in amorphous silicon thin film solar cells (a-Si TFSCs) due to their high transparency, conductivity and excellent light scattering properties. Recently, plasma textured glass surface morphologies received much attention for light trapping in a-Si TFSCs. We report various plasma textured glass surface morphologies for the high efficiency of a-Si TFSCs. Plasma textured glass surface morphologies showed high rms roughness, haze ratio with micro- and nano size surface features and are proposed for future high efficiency of a-Si TFSCs.

홀 패턴 텍스쳐 표면에서 충돌하는 단일 액적의 젖음 특성 (Wetting Characteristic of Single Droplet Impinging on Hole-Patterned Texture Surfaces)

  • 문주현;이상민;정정열;이성혁
    • 한국분무공학회지
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    • 제20권3호
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    • pp.181-186
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    • 2015
  • This study presents the dynamic wetting characteristics of an impact droplet on hole-patterned textured surfaces. The flat surfaces were manufactured by a drilling machine to generate the micro-order holes, leading to make the surface hydrophobic. Other flat surfaces were fabricated by the anodizing technique to make hydrophilic texture surfaces with a nanometer order. For hydrophilic and hydrophobic textured surfaces with similar texture area fractions, the impinging droplet experiments were conducted and compared with flat surface cases. As results, an anodized textured surface decreases apparent equilibrium contact angle and increases contact diameters, because of increase in contact area and surface energy. This is attributed to more penetration inside holes from larger capillary pressure on nanometer-order holes. On the other hand, temporal evolution of the contact diameter is smaller for the hydrophobic textured surface from less penetration on the micro-order holes.

이불화제논 기상 식각에 의한 실리콘 기판의 표면 텍스쳐링 특성 (Characterizations of Surface Textured Silicon Substrated by XeF2 Etching System)

  • 김선훈;기현철;김두근;나용범;김남호;김회종
    • 전기학회논문지
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    • 제59권4호
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    • pp.749-753
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    • 2010
  • We investigated the haze and the surface roughness of textured Si substrates etched by $XeF_2$ etching system with the etching parameters of $XeF_2$ pressure, etching time, and etching cycle. Here the haze was obtained as a function of wavelength from the measured reflectance. The haze of textured Si substrates was strongly affected by the etching parameter of etching cycle. The surface roughness of textured Si substrates was calculated with the haze and the scalar scattering theory at the wavelength of 800 nm. Then, the surface roughness was compared with that measured by atomic force microscope. The surce roughness obtained by two methods was changed with the similar tendency n terms of $XeF_2$ etching conditions.

Simulation of Rough Surface of CIGS (CuInGaSe) Solar Cell by RCWA (Rigorous Coupled Wave Analysis) Considering the Incoherency of Light

  • Kim, Sung Chul
    • Journal of the Optical Society of Korea
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    • 제18권2호
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    • pp.180-183
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    • 2014
  • The surface of semiconductor solar cells, such as a-Si or CIGS (CuInGaSe) solar cells is not flat but textured in the microscopic domain. With textured surfaces, the optical reflectivity of a solar cell is different from that of flat surfaces in the wavelength region. In this paper, the effects of a textured surface on a CIGS solar cell are presented by RCWA (Rigorous Coupled Wave Analysis) method. The effect of incoherent light is also considered by RCWA with a Fourier analysis while conventional optical simulation uses the input light on the solar cell as coherent light. Using experimental results, the author showed that the RCWA method with a Fourier analysis is a proper method to simulate the optical properties of CIGS solar cells.

윤활영역에서 멀티크기 Laser Surface Texturing 효과 (Improvement of Tribological Characteristics of Multi-Scale Laser-Textured Surface in terms of Lubrication Regime)

  • 김종형;최시근;다윗제네베세구;정용섭;김석삼
    • Tribology and Lubricants
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    • 제30권1호
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    • pp.59-63
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    • 2014
  • Laser Surface Texturing(LST) is a surface engineering process used to improve tribological characteristics of materials by creating patterned microstructures on the mechanical contact surface. In LST technology, a pulsated laser beam is used to create arranged dimples on a surface by a material ablation process, which can improve such as load capacity, wear resistances, lubrication lifetime, and reduce friction coefficients. In the present study, the effect of multi-scale LST on lubricant regime was investigated. A pulsed Nd:YAG laser was applied on the bearing steel(AISI 52100) to create arranged dimples. To optimize the surface texturing effect on friction, multi-scale texture dimples with some specific formula arrays were fabricated by combining circles, ellipses and the laser ablation process. The tribological testing of multi-scale textured surface was performed by a flat-on-flat unidirectional tribometer under lubrication and the results compared with that of the non-textured surface. Through an increase in sliding speed, the beneficial effect of multi-scale LST performance was achieved. The multi-scale textured surface had lower friction coefficient performances than the non-textured surface due to the hydrodynamic lubrication effect.

컴퓨터 하드디스크 드라이브의 레이저 텍스쳐 디스크와 미케니칼 텍스쳐 디스크의 마모거동에 관한 연구 (A Tribological Investigation on Laser Textured Disk and Mechanically Textured Disk of Computer Hard Disk Drive)

  • 김우석;김도형;황평;김장교
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 1998년도 제28회 추계학술대회
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    • pp.106-114
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    • 1998
  • Tribological investigation of ultra thin film magnetic storage disks which have two different kinds of start/stop zone of laser textured bump disk and mechanically textured disk for before CSS test and after CSS test. To measure surface roughness, height reduction before/after CSS test and obtain accurate topographies, AFM(Atomic Force Microscope) which is most powerful recently has been used. The result of statistical analysis showed that both laser textured bump height and mechanically textured zone height have been reduced about 4~7nm after 15000 cycle CSS test. Using commercial Nano-Indenter, ramping load scratch test has been performed to investigate friction characteristic for laser textured zone and mechanically textured zone before/after CSS test.

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