• Title/Summary/Keyword: Surface modification

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Effect of Surface Modification Process Conditions on Properties of Aramid Paper (아라미드 종이의 특성에 대한 표면 개질 과정 조건의 영향)

  • Sha, Lizheng;Zhao, Huifang
    • Polymer(Korea)
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    • v.37 no.2
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    • pp.196-203
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    • 2013
  • Surface modification of meta-aramid fibers was performed by phosphoric acid treatment. Surface morphology and element composition of untreated and treated fibers were analyzed by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). Effects of surface modification on the mechanical strength of aramid papers made from meta-aramid fibers and fibrid were investigated. Surface modification conditions were optimized by response surface analysis (RSA). Results show that phosphoric acid treatment increases the surface roughness and oxygen content of aramid fibers. They improve the interface bonding strength between aramid fibers and fibrid, which improves the tensile strength of aramid papers. The results of response surface analysis indicate that the tensile strength of aramid papers increases by 47.5% and reaches the maximum when meta-aramid fibers are treated with 21.1wt% phosphoric acid solution at $39.3^{\circ}C$ for 36.7 min.

Advanced Surface Modification Techniques for Enhancing Osseointegration of Titanium Implant (임상가를 위한 특집 1 - 티타늄 임플란트의 골융합 증진을 위한 최신 표면처리 기술)

  • Song, Ho-Jun
    • The Journal of the Korean dental association
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    • v.48 no.2
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    • pp.96-105
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    • 2010
  • Titanium implant is used as the most popular dental material for replacement of missing teeth recently. A lot of studies on the surface modification of titanium implant have been carried out for enhancing osseointegration. The surface modification techniques could be classified as follows; topographic modifications which provide roughness and porosity, chemical surface modificationss or deposition of osseoconductive materials, and biochemical modifications to immobilize bone growth factors on titanium surface. In this study, the current and ongoing surface modification techniques and its typical characteristics used in clinics were reviewed. In the future, study and implication about biochemical modifications including patient' s individual characteristics will be important.

Heavy Metal Removal from Drinking Water using Bipolar Surface Modified Natural Mineral Adsorbents (천연광물의 양극성 표면개질을 이용한 상수원수 중 중금속제거 특성)

  • Kim, Nam-youl;Kim, Younghee
    • Journal of Environmental Health Sciences
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    • v.45 no.6
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    • pp.561-568
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    • 2019
  • Objectives: The most commonly detected heavy metals in rocks and soils, including Pb, Cd, Cu, Fe, Mn and As, are representative pollutants discharged from abandoned mines and have been listed as potential sources of contamination in drinking water. This study focused on increasing the removal efficiency of heavy metals from drinking water resources by surface modification of natural adsorbents to reduce potential health risks. Methods: Iron oxide coating and graft polymerization with zeolites and talc was conducted for bipolar surface modification to increase the combining capacity of heavy metals for their removal from water. The removal efficiency of heavy metals was measured before and after the surface modification. Results: The removal efficiency of Pb, Cu, and Cd by surface modified zeolite showed 100, 92, and 61.5%, respectively, increases compared to 64, 64, and 38% for non-modified zeolite. This implies that bipolar surface modified natural adsorbents have a good potential use in heavy metal removal. The more interesting finding is the removal increase for As, which has both cation and anion characteristics showing 27% removal efficiency where as non-modified zeolite showed only 2% removal. Conclusions: Zeolite is one of the most widely used adsorptive materials in water treatment processes and bipolar surface modification of zeolite increases its applicability in the removal of heavy metals, especially As.

Effect of the Amplitude in Ultrasonic Nano-crystalline Surface Modification on the Corrosion Properties of Alloy 600

  • Kim, Ki Tae;Kim, Young Sik
    • Corrosion Science and Technology
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    • v.18 no.5
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    • pp.196-205
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    • 2019
  • Surface modification techniques are known to improve SCC by adding large compressive residual stresses to metal surfaces. This surface modification technology is attracting attention because it is an economical and practical technology compared to the maintenance method of existing nuclear power plants. Surface modification techniques include laser, water jet and ultrasonic peening, pinning and ultrasonic Nano-crystal surface modification (UNSM). The focus of this study was on the effect of ultrasonic amplitude in UNSM treatment on the corrosion properties of Alloy 600. A microstructure analysis was conducted using an optical microscope (OM), scanning electron microscope (SEM) and electron backscattering diffraction (EBSD). A cyclic polarization test and AC-impedance measurement were both used to analyze the corrosion properties. UNSM treatment influences the corrosion resistance of Alloy 600 depending on its amplitude. Below the critical amplitude value, the pitting corrosion properties are improved by grain refinement and compressive residual stress, but above the critical amplitude value, crevices are formed by the formation of overlapped waves. These crevices act as corrosion initiators, reducing pitting corrosion resistance.

Enhanced Electrochemical Properties of All-Solid-State Batteries Using a Surface-Modified LiNi0.6Co0.2Mn0.2O2 Cathode

  • Lim, Chung Bum;Park, Yong Joon
    • Journal of Electrochemical Science and Technology
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    • v.11 no.4
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    • pp.411-420
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    • 2020
  • Undesirable interfacial reactions between the cathode and sulfide electrolyte deteriorate the electrochemical performance of all-solid-state cells based on sulfides, presenting a major challenge. Surface modification of cathodes using stable materials has been used as a method for reducing interfacial reactions. In this work, a precursor-based surface modification method using Zr and Mo was applied to a LiNi0.6Co0.2Mn0.2O2 cathode to enhance the interfacial stability between the cathode and sulfide electrolyte. The source ions (Zr and Mo) coated on the precursor-surface diffused into the structure during the heating process, and influenced the structural parameters. This indicated that the coating ions acted as dopants. They also formed a homogenous coating layer, which are expected to be layers of Li-Zr-O or Li-Mo-O, on the surface of the cathode. The composite electrodes containing the surface-modified LiNi0.6Co0.2Mn0.2O2 powders exhibited enhanced electrochemical properties. The impedance value of the cells and the formation of undesirable reaction products on the electrodes were also decreased due to surface modification. These results indicate that the precursor-based surface modification using Zr and Mo is an effective method for suppressing side reactions at the cathode/sulfide electrolyte interface.

A Study on the Ultrasonic Nano Crystal Surface Modification(UNSM) Technology and It's Application (초음파 나노표면개질기술의 특성과 활용방안 연구)

  • Pyoun, Young-Sik;Park, Jeong-Hyeon;Cho, In-Ho;Kim, Chang-Sik;Suh, Chang-Min
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.3
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    • pp.190-195
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    • 2009
  • All the failure in fatigue of torsion, bending and rolling contact, and in sliding wear begins mostly from surface. So much efforts have been invested to the surface technology which deal these problems during past decades, but the industrial demand keeps growing and more significant requirements are added to researchers and engineers. Nano crystal surface modification technology which makes the surface layers into nano crystalline, induces big and deep compressive residual stress, increases surface hardness, improves surface hardness, and make micro dimples structure on surface is an emerging technology which can break limits of current surface technology and relieve the burden of researchers and engineers. In this study, a nano crystal surface modification technology which is calling UNSM(Ultrasonic nano crystal surface modification) technology, is introduced and how it has been applied to industry to solve these failure problems is explained.

Surface Modification of Polymethyl methacrylate(PMMA) by Laser Surface Treatment for Microfluidic Chip (유체소자 성능향상을 위한 Polymethyl methacrylate(PMMA)의 레이저 표면처리)

  • Shin, Sung-Kwon;Lee, Sang-Don;Lee, Cheon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.2
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    • pp.334-337
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    • 2007
  • After the advent of micro-Total Analysis Systems(${\mu}-TAS$) based on silicon various polymer for microfluidic chip has been studied. Polymer materials for microfluidic compared with silicon and glass which were traditional materials of a microfluidic chip, have the advantages of economical efficiency simple manufacturing process and wide materials selectivity corresponding to fluids. Surface energy of polymers we, however lower than silicon or glass. To overcome this problem, various surface modification methods have been investigated. The surface modification using laser has the advantage of the simple experiment that only directly irradiated laser beam on the material surface in the air. This work discuss the surface modification of polymethly methacrylate(PMMA) by 4th harmonic Nd:YAG laser (${\lambda}266nm$, pulse) treatment. After the laser treatment, the PMMA surface was investigated using a contact angle measuring instrument. The contact angle was decreased with a increase of the surface oxygen content. This result means the surface energy of PMMA was increased by the laser treatment without changing of its bulk characteristics.

Recent Advances in Carbon-Nanotube-Based Epoxy Composites

  • Jin, Fan-Long;Park, Soo-Jin
    • Carbon letters
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    • v.14 no.1
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    • pp.1-13
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    • 2013
  • Carbon nanotubes (CNTs) are increasingly attracting scientific and industrial interest because of their outstanding characteristics, such as a high Young's modulus and tensile strength, low density, and excellent electrical and thermal properties. The incorporation of CNTs into polymer matrices greatly improves the electrical, thermal, and mechanical properties of the materials. Surface modification of CNTs can improve their processibility and dispersion within the composites. This paper aims to review the surface modification of CNTs, processing technologies, and mechanical and electrical properties of CNT-based epoxy composites.

Surface modification by tribochemical treatment in-situ

  • Du, Da-Chang;Kim, Seock-Sam;Suh, Chang-Min
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.178-190
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    • 2001
  • Tribological conditions and additive chemistry between frictional Interfaces were discussed in the present paper. The principles of the tribochemical surface modification were drawn on the basis of data of literatures and experiments. Results of gear tests proved experimentally that the principles would have potential applications in industry.

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Surface Modification of Aluminum by Nitrogen-Ion Implantation

  • Kang Hyuk-Jin;Ahn Sung-Hoon;Lee Jae-Sang;Lee Jae-Hyung
    • International Journal of Precision Engineering and Manufacturing
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    • v.7 no.1
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    • pp.57-61
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    • 2006
  • The research on surface modification technology has been advanced to improve the properties of engineering materials. Ion implantation is a novel surface modification technology that enhances the mechanical, chemical and electrical properties of substrate's surface using accelerated ions. In this research, nitrogen ions were implanted into AC7A aluminum substrates which would be used as molds for rubber molding. The composition of nitrogenion implanted aluminum and distribution of nitrogen ions were analyzed by Auger Electron Spectroscopy (AES). To analyze the modified surface, properties such as hardness, friction coefficient, wear resistance, contact angle, and surface roughness were measured. Hardness of ion implanted specimen was higher than that of untreated specimen. Friction coefficient was reduced, and wear resistance was improved. From the experimental results, it can be expected that implantation of nitrogen ions enhances the mechanical properties of aluminum mold.