• Title/Summary/Keyword: Anodized surface

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Photoelectrochemical Properties of TiO2 Nanotubes by Well-Controlled Anodization Process (양극산화 제어에 의한 TiO2 나노튜브의 광전기화학 특성)

  • Jeong, Dasol;Kim, Donghyun;Jung, Hyunsung
    • Journal of the Korean institute of surface engineering
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    • v.52 no.6
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    • pp.298-305
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    • 2019
  • We investigated a correlation between morphology and photoelectrochemical properties of TiO2 nanotubes fabricated by well-controlled anodization processes. Anodization in an ethylene-glycol-based electrolyte solution accelerated the rapid grow rate of TiO2 nanotubes, but also cause problems such as delamination at the interface between TiO2 nanotubes and a Ti substrate, and debris on the top of the nanotube. The applied voltages for the anodization of TiO2 were adjusted to avoid the interface delamination. The heat treatment and the anodizing time were also controlled to enhance the crystallinity of the as-prepared TiO2 nanotubes and to increase the surface area with the varied length of the anodized TiO2 nanotubes. Additionally, a 2-step anodization process was utilized to remove the debris on the tube top. The photoelectrochemical properties of TiO2 nanotubes prepared with the carefully tailored conditions were investigated. By removing the debris on TiO2 nanotubes, applied bias photon-to-current efficiency (ABPE) of TiO2 nanotubes increased up to 0.33%.

Study on the narrowed nanopores of anodized aluminum oxide template by thin-film deposition using e-beam evaporation (전자빔 증발법 박막 증착을 이용한 양극 산화 알루미늄 템플릿의 나노 포어 가공 연구)

  • Lee, Seung-Hun;Lee, Minyoung;Kim, Chunjoong;Kim, Kwanoh;Yoon, Jae Sung;Yoo, Yeong-Eun;Kim, Jeong Hwan
    • Journal of the Korean institute of surface engineering
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    • v.54 no.1
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    • pp.25-29
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    • 2021
  • The fabrication of nanopore membrane by deposition of Al2O3 film using electron-beam evaporation, which is fast, cost-effective, and negligible dependency on substance material, is investigated for potential applications in water purification and sensors. The decreased nanopore diameter owing to increased wall thickness is observed when Al2O3 film is deposited on anodic aluminum oxide membrane at higher deposition rate, although the evaporation process is generally known to induce a directional film deposition leading to the negligible change of pore diameter and wall thickness. This behavior can be attributed to the collision of evaporated Al2O3 particles by the decreased mean free path at higher deposition rate condition, resulting in the accumulation of Al2O3 materials on both the surface and the edge of the wall. The reduction of nanopore diameter by Al2O3 film deposition can be applied to the nanopore membrane fabrication with sub-100 nm pore diameter.

Three-dimensional porous films consisting of copper@cobalt oxide core-shell dendrites for high-capacity lithium secondary batteries (리튬이차전지용 고용량 음극을 위한 구리@코발트산화물 코어-쉘 수지상 기반 3차원 다공성 박막)

  • So-Young Joo;Yunju Choi;Woo-Sung Choi;Heon-Cheol Shin
    • Journal of the Korean institute of surface engineering
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    • v.56 no.1
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    • pp.104-114
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    • 2023
  • Three dimensional (3D) porous structures consisting of Cu@CoO core-shell-type nano-dendrites were synthesized and tested as the anode materials in lithium secondary batteries. For this purpose, first, the 3D porous films comprising Cu@Co core-shell-type nano-dendrites with various thicknesses were fabricated through the electrochemical co-deposition of Cu and Co. Then the Co shells were selectively anodized to form Co hydroxides, which was finally dehydrated to get Cu@CoO nanodendrites. The resulting electrodes exhibited very high reversible specific capacity almost 1.4~2.4 times the theoretical capacity of commercial graphite, and excellent capacity retention (~90%@50th cycle) as compared with those of the existing transition metal oxides. From the analysis of the cumulative irreversible capacity and morphology change during charge/discharge cycling, it proved that the excellent capacity retention was attributed to the unique structural feature of our core-shell structure where only the thin CoO shell participates in the lithium storage. In addition, our electrodes showed a superb rate performance (70.5%@10.8 C-rate), most likely due to the open porous structure of 3D films, large surface area thanks to the dendritic structure, and fast electron transport through Cu core network.

Photocatalytic and photoelectrocatalytic properties of anodic titanium dioxide nanotubes based on anodizing conditions (양극산화 조건에 따른 이산화티타늄 나노튜브의 광촉매 및 광전기화학적 특성)

  • Yeonjin Kim;Rin Jung;Jaewon Lee;JeongEun Yoo;Kiyoung Lee
    • Journal of the Korean institute of surface engineering
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    • v.56 no.2
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    • pp.137-146
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    • 2023
  • Nanosized TiO2 has been widely investigated in photoelectrochemical or photocatalytic applications due to their intrinsic properties such as suitable band position, high photocorrosion resistance, and surface area. In this study, to achieve the high efficiency in photoelectrochemical and photocatalytic performance, TiO2 nanotubular structures were formed by anodization at various temperatures and times. The morphological and crystal structure of the anodized TiO2 nanotubes (NTs) were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD). The photoelectrochemical (PEC) properties and incident photon-to-current conversion efficiency (IPCE) of the TiO2 NTs were studied with different lengths and morphologies. From the detailed investigations, the optimum thickness of TiO2 nanotubes was 3 ㎛. Moreover, we found that the optimum photocatalytic pollutant removal efficiency of TiO2 nanotubes for photodegradation of Rhodamine B (RhB) under simulated solar light was 5.34 ㎛ of tube length.

Development of a Returnable Folding Plastic Box RFID Module for Agricultural Logistics using Energy Harvesting Technology (에너지 하베스팅 기술을 활용한 농산물 물류용 리턴어블 접이식 플라스틱 상자 RFID 모듈 개발)

  • Jong-Min Park;Hyun-Mo Jung
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.29 no.3
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    • pp.223-228
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    • 2023
  • Sustainable energy supplies without the recharging and replacement of the charge storage device have become increasingly important. Among various energy harvesters, the triboelectric nanogenerator (TENG) has attracted considerable attention due to its high instantaneous output power, broad selection of available materials, eco-friendly and inexpensive fabrication process, and various working modes customized for target applications. In this study, the amount of voltage and current generated was measured by applying the PSD profile random vibration test of the electronic vibration tester and ISTA 3A according to the time of Anodized Aluminum Oxide (AAO) pore widening of the manufactured TENG device Teflon and AAO. The discharge and charging tests of the integrated module during the random simulated transport environment and the recognition distance of RFID were measured while agricultural products (onion) were loaded into the returnable folding plastic box. As a result, it was found that AAO alumina etching processing time to maximize TENG performance was optimal at 31 min in terms of voltage and current generation, and the integrated module applied with the TENG module showed a charging effect even during the continuous use of RFID, so the voltage was kept constant without discharge. In addition, the RFID recognition distance of the integrated module was measured as a maximum of 1.4 m. Therefore, it was found that the surface condition of AAO, a TENG element, has a great influence on the power generation of the integrated module, and due to the characteristics of TENG, the power generation increases as the surface dries, so it is judged that the power generation can be increased if the surface drying treatment (ozone treatment, etc.) of AAO is applied in the future.

A study of mesenchymal stem cell proliferation and surface characteristics of the titanium discs coated with MS275/PLGA by an electrospray (Electrospray법을 이용한 MS275/PLGA submicron 코팅 티타늄에서의 표면변화와 간엽줄기세포증식에 관한 연구)

  • Yoo, Soo-Yeon;Kim, Seong-Kyun;Heo, Seong-Joo;Koak, Jai-Young;Lee, Joo-Hee;Park, Yoon-Kyung;Kim, Ena
    • The Journal of Korean Academy of Prosthodontics
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    • v.50 no.4
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    • pp.285-291
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    • 2012
  • Purpose: This study was conducted to identify the surface characteristics of titanium discs coated with MS275/PLGA by electrospray and which is effective to mesenchymal stem cell proliferation. Materials and methods: We used anodized surface coated with PLGA as a control group and anodized surface coated with MS275 $0.5{\mu}M$, $1{\mu}M$, $1.5{\mu}M$ as test groups. To examine that the coating particles are nanometer sized, FE-SEM was used and AFM was utilized to determine the difference of coating surface roughness. We checked the mesenchymal stem cell proliferation by using MTT assay on $1^{st}$, $4^{th}$, $7^{th}$ days. Results: There was no significant difference between control groups and test groups in AFM results (P>.05). In MTT assay results, mesenchymal stem cell proliferation was increased with time, at $7^{th}$ day, cell viability on discs coated with $1.5{\mu}M$ MS275 was significantly higher than control group (P<.05). As SEM showed, the number of cells on all discs was increased and the morphology of cell attachment was also wider and closer with time. Conclusion: Titanium surface coated with MS275/PLGA showed significantly higher cell proliferation and the more density of MS275 was dispersed on titanium discs, the faster cells grew.

RESONANCE FREQUENCY ANALYSIS OF IMPLANTS WITH ANODIZED SURFACE OXIDES

  • Choi Jeong-Won;Heo Seong-Joo;Chang Ik-Tae;Koak Jai-Young;Han Jong-Hyun;Kim Yong-Sik;Lee Seok-Hyung;Yim Soon-Ho
    • The Journal of Korean Academy of Prosthodontics
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    • v.42 no.3
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    • pp.294-300
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    • 2004
  • The present experimental study was designed to address two issues. The first was to investigate whether oxidation voltage of titanium implants influenced bone tissue responses after an in vivo implantation. The second aim was to investigate secondary stability change after 1 to 3months period. Screw-shaped implants with a wide range of oxide properties were prepared by electrochemical oxidation methods, where the oxide thickness varied in the range of $3-15{\mu}m$. The micro structure revealed pore sizes of $1-3{\mu}m$, the crystal structures of the titanium oxide were amorphous, anatase and a mixture of anatase and rutile type. Bone tissue responses were evaluated by resonance frequency measurements that were undertaken 1 to 3months after insertion in the rabbit tibia. It was concluded that no statistical difference of RFA values was found between the groups, RFA gains after Imonth and 3months were calculated.

Nano Porous Tin Oxide Film Fabricated by Anodization (양극산화법으로 제작된 나노 다공성 주석 산화물 박막)

  • Mun, Kyu-Shik;Cheon, Se-Jon;No, Hee-Kyu;Chun, Seung-Chul;Park, Sung-Yong;Lee, Ro-Un;Park, Yong-Joon;Choi, Won-Youl
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.11a
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    • pp.328-328
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    • 2007
  • $SnO_2$ has a high potential for electric and electronic applications. We have anodized pure tin metal and nano porous tin oxide film was obtained on pure Sn. Nano porous tin oxide were grown by anodization in nonaqueous-base electrolytes at different potentials between 5 V and 100 V. Pore size of ~100nm was observed by FE-SEM. Pore sizes as a function of applied voltage and anodizing time were characterized. We obtained nano porous tin oxide film having an uniform pore size at low temperature. High specific surface area of $SnO_2$ will be very useful for gas sensor, lithium battery, and dye sensitized solar cell.

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Analysis of Power Generation Characteristics of TENG (Triboelectric Nanogenerator) Suitable for Domestic Transport Environment (국내 수송환경에 적합한 마찰전기 나노발전기의 발전특성 분석)

  • Jong-Min, Park;Hyun-Mo, Jung
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.28 no.3
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    • pp.193-199
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    • 2022
  • Sustainable energy supplies without the recharging and replacement of charge storage device have become increasingly important. Among various energy harvesters, the triboelectric nanogenerator (TENG) has attracted considerable attention due to its high instantaneous output power, broad selection of available materials, eco-friendly and inexpensive fabrication process, and various working modes customized for target applications. The TENG harvests electrical energy from wasted mechanical energy in the ambient environment. TENG devices are very likely to be used in next-generation renewable energy and energy harvesting. TENG devices have the advantage of being able to manufacture very simple power devices. In this experiment, various organic dielectrics and inorganic dielectrics were used to improve the open voltage of TENG, Among the various organic dielectrics, Teflon-based FEP, which has the highest electron affinity, showed the highest open voltage and Al electrode was fabricated on Teflon substrate by sputtering deposition process. And AAO (Anodized Aluminum Oxide) nanostructures were applied to maximize the specific surface area of the TENG device. The power generation of TENG within the acceleration level (0.25, 0.5, 1.0, 1.5 and 2 G) and the frequency range (5-120 Hz) of the domestic transport environment was up to 4 V.

Investigation of Functional 6061 Aluminum Alloy Oxide Film with Anodization Voltage and its Corrosion Resistance

  • Jisoo Kim;Chanyoung Jeong
    • Corrosion Science and Technology
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    • v.22 no.6
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    • pp.399-407
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    • 2023
  • This study investigated the formation of oxide films on 6061 aluminum (Al) alloy and their impacts on corrosion resistance efficiency by regulating anodization voltage. Despite advantageous properties inherent to Al alloys, their susceptibility to corrosion remains a significant limitation. Thus, enhancing corrosion resistance through developing protective oxide films on alloy surfaces is paramount. The first anodization was performed for 6 h with an applied voltage of 30, 50, or 70 V on the 6061 Al alloy. The second anodization was performed for 0.5 h by applying 40 V after removing the existing oxide film. Resulting oxide film's shape and roughness were analyzed using field emission-scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). Wettability and corrosion resistance were compared before and after a self-assembled monolayer (SAM) using an FDTS (1H, 1H, 2H, 2H-Perfluorodecyltrichlorosilane) solution. As the first anodization voltage increased, the final oxide film's thickness and pore diameter also increased, resulting in higher surface roughness. Consequently, all samples exhibited superhydrophilic behavior before coating. However, contact angle after coating increased as the first anodization voltage increased. Notably, the sample anodized at 70 V with superhydrophobic characteristics after coating demonstrated the highest corrosion resistance performance.