• Title/Summary/Keyword: Coated layer

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Electromagnetic Interference Shielding Effectiveness Properties of Ag-Coated Dendritic Cu Fillers Depending on pH of Galvanic Displacement Reaction for Ag Seed Layer and Contents of Deposited Ag Layer (은 코팅 구리 덴드라이트 필러 제조 시 은 시드층 형성을 위한 갈바닉 치환반응 pH 제어 및 은함량에 따른 전자파 차폐 특성)

  • Im, Dongha;Park, Su-Bin;Jung, Hyunsung
    • Journal of the Korean institute of surface engineering
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    • v.51 no.5
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    • pp.263-270
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    • 2018
  • Ag-coated Cu dendrites were prepared as a filler for an electromagnetic interference shielding application. Ag layers on the Cu dendrites was coated by two approaches. One is a direct autocatalytic plating with a reducing agent. The other approach was achieved by two-step plating, a galvanic displacement reaction to form Ag seed layers on Cu following by an autocatalytic plating with a reducing agent. The procedure-dependent average particle size and tap density of Ag-coated Cu dendrites were characterized. The electrical resistance and electromagnetic interference shielding effect (EMI SE) were analyzed with the Ag-coated Cu dendrites prepared in the two approaches. Additionally, the content of the Ag coated on Cu dendrites was controlled from 2% to 20%. The electrical resistance and EMI SE were critically determined by Ag contents coated on Cu.

Characterization of TiAlN Coated Layer with Heat Treatment Prepared by R.F Magnetron Sputtering (R.F magnetron sputtering법으로 제조된 TiAlN 코팅 층의 열처리 특성)

  • Song, Dong Hwan;Yang, Gwon Seung;Lee, Jong Kook
    • Journal of the Korean Society for Heat Treatment
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    • v.19 no.4
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    • pp.225-229
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    • 2006
  • TiAlN coatings are available in various industry fields as a wear resistant coating for high-speed machining, due to its high hardness, excellent oxidation and corrosion resistance. The corrosion resistance of TiAlN multilayer coatings is better than that of single TiN coatings. Most of TiAlN coated layers were formed by heat treatment of coating layers with a non-stoichiometric $Ti_xAl_{1-x}N$. In this study, TiAlN coated layer was prepared by R.F magnetron sputtering and investigated the thermal behavior for heat treatment at various temperature in tube furnace. The formation of large particles with porous microstructure and phase change from HCP to FCC were observed on coated layer during heat treatment over $850^{\circ}C$ and it reduced the corrosion resistance of coated TiAlN layers.

Study on CeO2 Single Buffer on RABiTS for SmBCO coated Conductor (SmBCO 초전도 층착을 위한 RABiTS상의 CeO2 단일 버퍼 연구)

  • Kim, Tae-Hyung;Kim, Ho-Sup;Lee, Nam-Jin;Ha, Hong-Soo;Ko, Rock-Kil;Ha, Dong-Woo;Song, Kyu-Jeong;Oh, Sang-Soo;Park, Kyung-Chae
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.20 no.6
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    • pp.546-549
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    • 2007
  • As a rule, high temperature superconducting coated conductors have multi-layered buffers consisting of seed, diffusion barrier and cap layers. Multi-buffer layer deposition requires longer fabrication time. This is one of main reasons which increases fabrication cost. Thus, single buffer layer deposition seems to be important for practical coated conductor process. In this study, a single layered buffer deposition of $CeO_2$ for low cost coated conductors has been tried using thermal evaporation technique. 100 nm-thick $CeO_2$ layers deposited by thermal evaporation were found to act as a diffusion layer. $1\;{\mu}m-thick$ SmBCO superconducting layers were deposited by thermal co-evaporation on the $CeO_2$ buffered Ni-5%W substrate. Critical current of 90 A/cm was obtained for the SmBCO coated conductors.

Effect of Coating Time on the Property of TiN-Coated Layer on High Speed Steel by Arc Ion Plating (AIP 코팅법에서 코팅 시간이 고속도강의 TiN 코팅층 성질에 미치는 영향)

  • Kim, B.J.;Joun, M.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2006.05a
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    • pp.308-313
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    • 2006
  • The effect of coating time on surface properties of the TiN-coated high speed steel(SKH51) by arc ion plating is and presented in this paper. Surface roughness, micro-hardness, coated thickness, atomic distribution of TiN and adhesion strength are measured for various coating times. It has been shown that the coating time has a deep influence more than 60 minites on the micro-hardness, coated thickness, atomic distribution of Ti and adhesion strength of the SKH51 steels, but that the coating time has little influence on the surface roughness.

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Enhancenent of Wear Resistance of TiN Coated High Speed Steel Tools through Improving some Coating Processes (코팅공정 개선에 의한 TiN코팅 고속도강 공구의 내마모특성 향상)

  • Lee, Y.M.;Son, Y.H.;Kim, H.S.;Back, J.Y.
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.11
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    • pp.32-37
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    • 1996
  • Using the are ion plating(AIP) process, TiN coating was deposited onto high speed steel substrates. The effects of coating thickness, titanisum interlayer and shield on wear resisting capability of the coated tools were investigated. In order to promote good adhesion between the substrate and the TiN coating a thin Ti interlayer was deposited. A shield was set up also between Ti target and high speed steel substrates to prevent molten droplets from reaching the substrate. Three series of varying thickness of TiN coated layer were prepared with or without the Ti interlayer, and with or without the shield. The tools with the Ti layer and the shield showed longer tool lifes than those of other series of tools and the commercially available TiN coated HSS tools, by up to 70%.

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EFFECTS OF HYDROXYAPATITE AND TITANIUM-COATED DENTAL IMPLANTS ON BONE FORMATION AND MATURATION IN DOG (성견에서 수산화인산염 피개 IMZ임플란트와 티타늄 피개 IMZ임플란트주위의 골형성 및 골성숙 정도에 대한 비교연구)

  • Yoon, Hong-Cheol;Han, Dong-Hoo
    • The Journal of Korean Academy of Prosthodontics
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    • v.33 no.2
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    • pp.317-334
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    • 1995
  • The purpose of this study was to compare the bone formation, maturation around HA-and titaniumcoated dental implants in dog. 5 hydroxyapatite coated IMZ implants and 5 titanium coated IMZ implants were placed into the previously extracted site in the mandible of 5 adults dogs. All dogs were injected intravenously Tetracycline, Alizalin red S, and Calcein for bone fluorescent labelling, After the experimental period of 16weeks, the dogs were sacrificed and tissue samples around the implants were obtained. Microscopic observations(ligth, polariged and fluorescence microscope), morphometric analysis, line profile with EPMA, and quantitative analysis for Ca,P, and Ti were performed. The results were as follows ; 1. Bone maturations around the implants were relatively lower than those of natural teeth. No significant differences in bone maturation and remodeling patterns were observed between the two implants groups. 2. Calcification of bone surrounding the implants was initiated in 8-11 weeks for HA-coated implants, while it took 11 weeks or more for Ti-coated implants. 3. Bone-to-implants contact ratio of 82.63% was recorded for HA-coated group and 72.25% for titanium coated group, with no significant difference between the two groups. 4. Bone around the implants exhibited reduced quantity of Ca and P in the $100{\mu}m$ region relative to natural teeth, while the rest of the regions showed no statistical differences. No significant differences were found between the two implant groups. 5. There was a separation of HA layer from the implant core and subsequent infiltration of inflammatory cells into the resulting space in the HA-coated implants, and evidences of phagocytosis of HA particles by macrophages. Bone calcification was more rapid around HA-coated implants compared to titanium-coated implants, but HA coated implants did not show any significant differences either in the degree of calcification or the bone-to-implant contact ratio over Ti coated implants. HA coated implants may have complications associated with HA absorption and separation of HA layer from the implant core.

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Fabrication of Thick SmBCO/IBAD-MgO coated conductor (후막 SmBCO/IBAD-MgO 초전도 박막선재의 제조)

  • Lee, J.H.;Kang, D.K.;Ha, H.S.;Ko, R.K.;Oh, S.S.;Kim, H.K.;Yang, J.S.;Jung, S.W.;Moon, S.H.;Youm, D.;Kim, C.J.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.05a
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    • pp.9-9
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    • 2009
  • Coated conductor is required to have good critical current property for high efficiency of electric power applications. Until now, long coated conductor does not show high Jc over 3 MA/$cm^2$ in thick superconducting layer because of texture degradation by thick superconducting layer. In this study, in order to overcome this issue, thicker superconducting layer was deposited with optimized conditions to reduce the degradation of critical current density. SmBCO superconducting coated conductor was deposited with 1~3 um of thickness at $750\sim850^{\circ}C$ under 15~20 mTorr of oxygen partial pressure using batch type EDDC( evaporation using drum in dual chamber). The buffered substrate for superconducting layer deposition was used IBAD-MgO template with the architecture of $LaMnO_3/MgO/Y_2O_3/Al_2O_3$/Hastelloy. After fabrication of coated conductor, critical current was measured by 4-prove method under self-magnetic field and 77K. In addition, surface morphology and texture were analyzed by SEM and XRD, respectively. 3 um thick SmBCO coated conductor shows highest $I_C$ values of 638A/cm-w in 1 m long in the world.

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Preparation of Nanocrystalline TiO2 Coated Coal Fly Ash by Dropping Method of Coating Agent and Photocatalytic Characterization (페복제 적하법에 의한 나노 결정 TiO2 피복 석탄회의 제조와 광촉매 특성)

  • Yu, Yeon-Tae;Choe, Yeong-Yun;Kim, Byeong-Gyu
    • Korean Journal of Materials Research
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    • v.12 no.5
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    • pp.334-340
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    • 2002
  • $TiO_2$-coated fly ash was synthesized by dropping method of coating agent in order to get $TiO_2$ coating layer with high photocatalytic activity on the surface of coal fly ash. The properties of the $TiO_2$ coating layer such as morphology, crystal structure, crystal size and photocatalytic activity were compared with those of the $TiO_2$-coated fly ash prepared by the traditional method of precipitation. $TiCl_4$ aqueous solution was used as a titanium stock solution and $NH_4HCO_3$ was used as a precipitant. The $TiO_2$ coating layer obtained by dropping method of coating agent was more uniform than that coated by precipitation. However, the crystal of $TiO_2$ coated by dropping method of coating agent was easy to grow by heat treatment because of the small primary particle size and bulky morphology, and its photocatalytic activity was consequently lower than that of the $TiO_2$ coated by precipitation. The $TiO_2$ coating layer obtained by both methods had a crystal structure of anatase, and the temperature of phase transformation into rutile was 90$0^{\circ}C$. The minimum crystal size of $TiO_2$ for the highest photocatalytic activity was found to be about 10nm.

The Development of Water-Soluble Black Coloring Agent and Its Application (수용성 흑색 착색제의 개발과 이의 응용)

  • Kim, M.G.;Jung, B.H.;Moon, M.J.;Kim, S.S.
    • Journal of the Korean Society for Heat Treatment
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    • v.15 no.5
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    • pp.213-218
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    • 2002
  • In order to develop the economic and environmental water-soluble black coloring agent, some adequate chemical mixtures were mixed and this solution was applied to coat quenched and tempered 51B20 steel bolt. Some basic properties of the solution and characteristics of the coated film in addition to the corrosion resistance were investigated. The developed 100 kg of water-soluble black coloring agent solution was a chemical mixture consisted of 10 kg of aqueous coloring agent, 40 kg of surface active agent, 0.3 kg of anti-foam agent and $50{\ell}$ of water. The coated film of the bolt was composed of hard layer of about $2{\mu}m$ and the disbondable soft layer of about $4{\mu}m$ above the hard layer. Many surface active agents peaks and a few hydrophilic peaks were observed in the coated film. Surface roughness value of the coated bolt was lower than that of the non-coated bolt. Corrosion resistance of the coated bolt considerably improved and also relatively showed a good polarization resistance at test condition of $40^{\circ}C$ colorizing temperature and 5% the solution concentration in 3% NaCl anodic polarization test. Initial appearance time of the surface rust was greatly retarded owing to the coated film in salt spray test.

The Study on the Current Limiting Characteristics of YBCO Coated Conductor with Different kinds of Stabilization Layer Applied to SFCL Using Iron Core and Coil (철심과 권선을 이용한 전류제한기에 적용시킨 안정화층이 다른 YBCO Coated Conductor의 전류제한 특성에 관한 연구)

  • Lee, Dong-Heok;Du, Ho-Ik;Kim, Yong-Jin;Han, Byoung-Sung;Yim, Seong-Woo;Han, Sang-Chul;Lee, Jeong-Phil
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.10
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    • pp.788-792
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    • 2010
  • The yttrium-barium-copper-oxide (YBCO) coated conductor, which supplement the fault of the existing superconducting current-limit materials YBCO thin film, bismuth-strontium-calcium-copper-oxide(BSCCO) wire and bulk, has been improved its mechanical weakness and has high index; hence, after quench YBCO coated conductor could limit the fault current effectively because of fast resistance occurrence speed. Furthermore, it has wide applicable area as an current limit material because it shows different resistance occurrence tendency by the thickness and kind of stabilization material sputtered on the superconducting layer. Therefore, many researchers are carrying out the study of application of YBCO coated conductor to superconducting fault current limiter (SFCL) for making high quality current limit element, based on resistance type. On the other hand, the study for other type except resistance type has been rarely conducted for the application of YBCO coated conductor to SFCL as an current limit element. Consequently, in this study, YBCO coated conductor with different stabilization layer Cu and Stainless steel, is applied to SFCL using iron core and coil, and examine the many index points as an current limit element, such as current limit characteristic, the tendency of resistance occurrence, response time, the temperature trend for stability.