• Title/Summary/Keyword: hybrid materials

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Machinability Evaluation of Hybrid Ti2 Ceramic Composites with Conductivity in Micro Electrical Discharge Drilling Operation (전도성을 가지는 하이브리드 Ti2AlN 세라믹 복합체의 마이크로 방전드릴링에서 가공성 평가)

  • Heo, Jae-Young;Jeong, Young-Keun;Kang, Myung-Chang;Busnaina, Ahmed
    • Journal of Powder Materials
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    • v.20 no.4
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    • pp.285-290
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    • 2013
  • $Ti_2AlN$ composites are a laminated compounds that posses unique combination of typical ceramic properties and typical metallic(Ti alloy) properties. In this paper, the powder synthesis, SPS sintering, composite characteristics and machinability evaluation were systematically conducted. The random orientation characteristics and good crystallization of the $Ti_2AlN$ phase are observed. The electrical and thermal conductivity of $Ti_2AlN$ is higher than that of Ti6242 alloy. A machining test was carried out to compare the effect of material properties on micro electrical discharge drilling for $Ti_2AlN$ composite and Ti6242 alloy. Also, mixture table as a kind of tables of orthogonal arrays was used to know how parameter is main effective at experimental design. Consequently, hybrid $Ti_2AlN$ ceramic composites showed good machining time and electrode wear shape under micro ED-drilling process. This conclusion proves the feasibility in the industrial applications.

Characterization of Silica/EVOH Hybrid Coating Materials Prepared by Sol-Gel Method

  • Kim, Seong-Woo
    • Journal of the Korean Applied Science and Technology
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    • v.26 no.3
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    • pp.288-296
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    • 2009
  • In this study, the silica-based hybrid material with high barrier property was prepared by incorporating ethylene-vinyl alcohol (EVOH) copolymer, which has been utilized as packaging materials due to its superior gas permeation resistance, during sol-gel process. In preparation of this EVOH/$SiO_2$ hybrid coating materials, the (3-glycidoxy-propyl)-trimethoxysilane (GPTMS) as a silane coupling agent was employed to promote interfacial adhesion between organic and inorganic phases. As confirmed from FT-IR analysis, the physical interaction between two phases was improved due to the increased hydrogen bonding, resulting in homogeneous microstructure with dispersion of nano-sized silica particles. However, depending on the range of content of added silane coupling agent (GPTMS), micro-phase separated microstructure in the hybrid could be observed due to insufficient interfacial attraction or possibility of polymerization reaction of epoxide ring in GPTMS. The oxygen barrier property of the mono-layer coated BOPP (biaxially oriented polypropylene) film was examined for the hybrids containing various GPTMS contents. Consequently, it is revealed that GPTMS should be used in an optimum level of content to produce the high barrier EVOH/$SiO_2$ hybrid material with an improved optical transparency and homogeneous phase morphology.

Fabrication of PMMA-HfOx Organic-Inorganic Hybrid Resistive Switching Memory (PMMA-HfOx 유-무기 하이브리드 저항변화 메모리 제작)

  • Baek, Il-Jin;Cho, Won-Ju
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.3
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    • pp.135-140
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    • 2016
  • In this study, we developed the solution-processed PMMA-$HfO_x$ hybrid ReRAM devices to overcome the respective drawbacks of organic and inorganic materials. The performances of PMMA-$HfO_x$ hybrid ReRAM were compared to those of PMMA- and $HfO_x$-based ReRAMs. Bipolar resistive switching behavior was observed from these ReRAMs. The PMMA-$HfO_x$ hybrid ReRAMs showed a larger operation voltage margin and memory window than PMMA-based and $HfO_x$-based ReRAMs. The reliability and electrical instability of ReRAMs were remarkably improved by blending the $HfO_x$ into PMMA. An Ohmic conduction path was commonly generated in the LRS (low resistance state). In HRS (high resistance state), the PMMA-based ReRAM showed SCLC (space charge limited conduction). the PMMA-$HfO_x$ hybrid ReRAM and $HfO_x$-based ReRAM revealed the Pool-Frenkel conduction. As a result of flexibility test, serious defects were generated in $HfO_x$ film deposited on PI (polyimide) substrate. On the other hand, the PMMA and PMMA-$HfO_x$ films showed an excellent flexibility without defect generation.

Cement/PVDF hollow-fiber hybrid basement membrane: Preparation, microstructure, and separation application

  • Yabin, Zhang;Xiongfei, Du;Taotao, Zhao
    • Membrane and Water Treatment
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    • v.13 no.6
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    • pp.291-301
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    • 2022
  • In this study, cement/PVDF hollow-fiber hybrid membranes were prepared via a mixed process of diffusion-induced phase separation and hydration. The presence of X-ray diffraction peaks of Ca(OH)2, an AFt phase, an AFm phase, and C-S-H phase confirmed the hydration reaction. Good hydrophilicity was obtained. The cross-sectional and surface morphologies of the hybrid membranes showed that an asymmetric pore structure was formed. Hydration products comprising parallel plates of Ca(OH)2, fibrous ettringite AFt, and granulated particles AFm were obtained gradually. For the hybrid membranes cured for different time, the pore-size distribution was similar but the porosity decreased because of blocking of the hydration products. In addition, the water flux decreased with hydration time, and carbon retention was 90% after 5 h of rejection treatment. Almost all the Zn2+ ions were adsorbed by the hybrid membrane. The above results proved that the obtained membrane could be alternative as basement membrane for separation application.

Characteristics of Polyimide-silica Hybrid Materials Prepared from Alkoxide Precursor Using Sol-gel Process (졸-겔법을 이용하여 알콕사이드 전구체로부터 합성된 Polyimide-silica 혼성체의 특성)

  • Kim, Byoung-Woo;Lee, Sung-Hwan;Kim, Sung-Wan;Park, Jae-Hyun;Kim, Jun-Ho;Park, Seong-Soo;Park, Hee-Chan
    • Journal of the Korean Ceramic Society
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    • v.39 no.11
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    • pp.1063-1068
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    • 2002
  • Polyimide/silica(PI/silica) hybrid materials having physical or chemical bonds between the PI and silica network were prepared using sol-gel process through hydrolysis and polycondensation of tetraethoxysilane with the polyamic Acid(PAA) or end-capped PAA solution. PAA solution was synthesized by ring opening reaction of pyromellitic dianhydride and oxydianiline monomers in dimethyl acetamide solution. End-capped PAA solution was synthesized by the addition of 3-aminopropyltriethoxysilane in PAA solution. PI/silica hybrid samples were characterized by infrared spectroscopy, differential thermogravimetry, X-ray diffractometry, scanning electron microscopy, and tensile tester. It has been demonstrated that the properties of hybrid samples were affected by the silica content and the bond type between PI and silica.

Improve the Transparency of Liquid Crystal Display Using Hybrid Conductive Films Based on Carbon Nanomaterials

  • Shin, Seung Won;Kim, Ki-Beom;Jung, Yong Un;Hur, Sung-Taek;Choi, Suk-Won;Kang, Seong Jun
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.241.2-241.2
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    • 2014
  • We present highly transparent liquid crystal displays (LCDs) using hybrid films based on carbon nanomaterials, metal grid, and indium-tin-oxide (ITO) grid. Carbon based nanomaterials are used as transparent electrodes because of high transmittance. Despite of their high transmittance they have relatively high sheet resistance. To solve this problem, we applied grid and made hybrid conductive films based on carbon nanomaterials. Conventional photolithography processes were used to make a grid pattern of metal and ITO. To fabricate transparent conductive films, carbon nanotube (CNT) ink was spin coated on the grid pattern. The transparency of the conductive film was controlled by shape and size of the grid pattern and the thickness of CNT films. The optical transmittance of CNT-based hybrid films is 92.2% and sheet resistance is also reduced to $168{\Omega}/square$. These substrates were used for the fabrication of typical twisted nematic (TN) LCD cells. From the characteristics of LCD devices such as transmittance, operating voltage, voltage holding ratio our devices were comparable to those of pristine ITO substrates. The result shows that the hybrid conductive films based on carbon nanomaterials could be alternative of ITO for the highly transparent LCDs.

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An Overview of Self-Grown Nanostructured Electrode Materials in Electrochemical Supercapacitors

  • Shinde, Nanasaheb M.;Yun, Je Moon;Mane, Rajaram S.;Mathur, Sanjay;Kim, Kwang Ho
    • Journal of the Korean Ceramic Society
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    • v.55 no.5
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    • pp.407-418
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    • 2018
  • Increasing demand for portable and wireless electronic devices with high power and energy densities has inspired global research to investigate, in lieu of scarce rare-earth and expensive ruthenium oxide-like materials, abundant, cheap, easily producible, and chemically stable electrode materials. Several potential electrode materials, including carbon-based materials, metal oxides, metal chalcogenides, layered metal double hydroxides, metal nitrides, metal phosphides, and metal chlorides with above requirements, have been effectively and efficiently applied in electrochemical supercapacitor energy storage devices. The synthesis of self-grown, or in-situ, nanostructured electrode materials using chemical processes is well-known, wherein the base material itself produces the required phase of the product with a unique morphology, high surface area, and moderate electrical conductivity. This comprehensive review provides in-depth information on the use of self-grown electrode materials of different morphologies in electrochemical supercapacitor applications. The present limitations and future prospects, from an industrial application perspectives, of self-grown electrode materials in enhancing energy storage capacity are briefly elaborated.

Optimization of Processing Parameters of Compression Molding of Hybrid Thermoplastic Composites (Hybrid 열가소성 복합재료의 압축성형에서 공정변수의 최적화)

  • 이중희;허석봉;이봉신
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2001.10a
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    • pp.29-32
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    • 2001
  • The objective of this work was to optimize processing parameters of hybrid thermoplastic composites in compression molding. The mechanical properties of the composites manufactured with various forming conditions were measured to characterize processing parameters. Polypropylene(PP) composites containing randomly oriented long carbon fiber and carbon black were used in this work. The composite materials contained 5%, 10%, 15%, and 20% carbon fiber and 5%, 10%, 15%, 20%, and 25% carbon black by weight. Compression molding was conducted at various mold temperatures. The temperature of the material in the mid-plain was monitored during the forming. Crystallinity was also measured by using XRD. The tensile modulus of the composites increase, with increasing the mold temperature. However, the impact strength of the composites decreases as mold temperature increases.

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Mechanical and Thermal Properties of Phenolic Composite reinforced with Hybrid of PAN-based/Rayon-based Carbon Fabrics (PAN계/Rayon계 탄소 직물 하이브리드 복합재료의 역학적 특성 및 열적 특성에 관한 연구)

  • Kim, Jae-Hong;Park, Jong-Kyu;Jung, Kyung-Ho;Kang, Tae-Jin
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2005.04a
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    • pp.98-101
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    • 2005
  • The mechanical and thermal properties of PAN-based/Rayon-based carbon fabrics interply hybrid composite materials have been studied. Mechanical properties was improved with increasing amount of continuous PAN-based carbon fabrics. The erosion rate was calculated through torch test. The thermal conductivity of hybrid of spun PAN-based/continuous rayon-based carbon fabric is lower than others.

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Antimicrobial Ceramic Hybrid Polyethylene Films with Chamomile Extracts for Feed Packaging

  • Lee, Hye Sun;Chang, Jeong Ho
    • Journal of the Korean Ceramic Society
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    • v.54 no.3
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    • pp.228-234
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    • 2017
  • This work was achieved on the preparation of antimicrobial ceramic hybrid polyethylene films with natural chamomile extracts. The antimicrobial activity and various physicochemical properties of the prepared films were evaluated. Various natural products demonstrated antimicrobial activity. Among them, chamomile extracts showed strong activity and no cytotoxicity rather than that of the natural extracts. Porous ceramic materials were synthesized and demonstrated loading and controlled release of natural antimicrobial extracts. Furthermore, chamomile loaded ceramic hybrid films showed antimicrobial activity that was maintained for over 15 days.