• Title/Summary/Keyword: Ti addition

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The Effects of Ti-B Addition on the Unidirectional Solidification of Al (Ti-B 첨가(添加)에 의한 Al 의 응고조직(凝固組織)에 관(關)한 연구(硏究))

  • Song, Yeon-Soo;Lee, Kye-Wan
    • Journal of Korea Foundry Society
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    • v.7 no.4
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    • pp.358-365
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    • 1987
  • To investigate the grain refining mechanism of Al by the addition of Ti-B, the unidirectional solidifications of 99.9%Al and 99.7%Al were performed under the condition of varing the pouring temperature. The solidification modes of Al were studied by the cooling curve analyses, metallographic and microprobe examinations. The results were as follows: 1) Grains were most refined with an addition of 0.15wt.%Ti-0.021wt.%B but the grain size with 0.2wt.%Ti-0.028wt.%B was increased. 2) The grain size of 99.7wt.%Al was even more refined than that of 99.9wt.%Al with the same amount of Ti-B. 3) As the pouring temperature increased, the grain size of pure Al and an alloy with 0.lwt.%Ti-0.014wt.%B was increased. However, an alloy with 0.2wt.%Ti-0.028wt.%B did not show any effects of temperature. 4) TiC(Al-Ti) and (Al-Ti-C) were identified as nucleants for Al.

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Formation of a Core/Rim Structure in Ti(C, N)-based Cermets (Ti(C, N)계 써메트의 유심구조 형성거동)

  • Kim, Suk-Hwan
    • Journal of Powder Materials
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    • v.13 no.1 s.54
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    • pp.10-17
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    • 2006
  • Model experiment was introduced to obtain the formation of a core/rim structure by only liquid phase reaction in Ti(C, N)-based cermet alloys. Infiltrated Ti(C, N)-Ni, $MO_2C-Ni$, and TaC-Ni cermets were bonded to sandwiched specimen by heat treatment $1450^{\circ}C$ for 5hr. With nitrogen addition, both (Ti, Mo) (C, N) and (Ti, Ta) (C, N) rim structure was nucleated around comer of cuboidal Ti(C, N) core. However, equilibrium shapes of(Ti, Mo) (C, N) and (Ti, Ta) (C, N) rim were different possibly due to the effect of interface energy. The core/rim and rim! binder interfaces were parallel to each other with TaC addition, while rotated to each other with $MO_2C$ addition.

Effect of Silica Addition on Phase Transformation Characteristics of Heat-Treated Combustion-Synthesized TiO2 Nanoparticles (실리카가 첨가된 연소합성 TiO2 나노입자의 열처리에 따른 상변환 특성)

  • Kim, Min-Su;Lee, Gyo-Woo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.33 no.3
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    • pp.186-193
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    • 2009
  • In this article, the effect of silica addition on the phase transformation characteristics of $TiO_2$ nanoparticles synthesized by using an $O_2$-enriched coflow, hydrogen, diffusion flame was investigated. TTIP(titanium tetra-isopropoxide) and TEOS(tetraethyl-orthosilicate) were used as precursors for $TiO_2$ and $SiO_2$ nanoparticles, respectively. Based on the results from TEM and XRD analysis, it is believed that the silica addition on the flame synthesis of $TiO_2$ nanoparticles reduces the particle size distribution and raises the temperature of the phase transition from anatase to rutile. But the reduced sizes of the synthesized particles due to the silica addition made the sintering and phase transformation of particles more easily.

The hydration resistance improvement of MgO ceramics by $TiO_2$ addition ($TiO_2$ 첨가에 의한 MgO 세라믹스의 표현 수화 저항성 향상)

  • Ryu, Su-Chak;Kim, Jin-Kon;Hyun Cho
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.11 no.6
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    • pp.269-273
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    • 2001
  • The effect of $TiO_2$addition on the hydration reaction of MgO ceramics were studied after being heated at $1450^{\circ}C$. The pure MgO ceramics showed significant weight change after exposure to water due to the hydration reaction through the formation of $Mg(OH)_2$while $TiO_2$-added MgO ceramics did not. The $Mg_2TiO_4$phase were observed in the $TiO_2$-added MgO ceramics sintered at 145$0^{\circ}C$. Bulk density increased as the amount of $TiO_2$increased and the apparent porosity and water absorption decreased by $TiO_2$addition. The hydration resistance of MgO ceramics was found to be improved by $TiO_2$addition.

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Effects of Alloying Element and Heat Treatment on Properties of Cu-Ti Alloys

  • Suk, Han-Gil;Hong, Hyun-Seon
    • Journal of the Korean institute of surface engineering
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    • v.42 no.5
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    • pp.246-249
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    • 2009
  • Cu-Ti alloys with titanium in the range of 0.5-6.0 wt% were developed to evaluate the effect of the titanium content and heat treatment on microstructure, hardness, and electrical conductivity. The hardness of the Ti-added copper alloys generally increased with the increase in titanium content and hardening was effective up to the 2.5 wt%-Ti addition. Microstructural examination showed that the second phase of $Cu_4Ti$ started to precipitate out from the 3.0 wt% Ti-addition, and the precipitate size and volume fraction increased with further Ti addition. Aging of the present Cu-Ti alloys at $450^{\circ}C$ for 1 h increased the hardness; however, the further aging up to 10 h did not much change the hardness. In the present study, it was inferred that in optimal Ti addition and aging condition Cu-Ti alloy could have the hardness and electrical conductivity values which are comparable to those of commercial Cu-Be alloy.

Piezoelectric Properties of Pb-free Bi(Na,K)TiO3-SrTiO3 Ceramics with the Amount of La2O3 Addition (La2O3첨가에 따른 무연 Bi(Na,K)TiO3-SrTiO3 세라믹스의 압전 특성)

  • 류주현;이현석;박창엽;정광현;이덕출;정영호;홍재일
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.8
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    • pp.830-834
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    • 2004
  • In this study, lead-free pirzoelectric ceramics were investigated for pressure sensor applications as a function of the amount of ${La}_2{O}_3$ addition at $Bi(Na, K)Ti{O}_3-SrTi{O}_3$system. With increasing the amount of addition, the density and dielectric constant increased up to 0.9 wt% ${La}_2{O}_3$ addition and decreased above 0.9 wt% ${La}_2{O}_3$addition. Electromechanical coupling factor( $K_{P}$) showed the maximum value at 0.2 wt% ${La}_2{O}_3$addition and decreased above 0.2 wt% ${La}_2{O}_3$ addition. Electromechanical coupling $factor{(K)}_P$, density, dielectric constant$(\varepsilon_\Gamma)$, piezoelectric constant$(d_33)$ and curie temperature$(T_C)$ showed optimum value of 0.40, 5.75 g/㎤, 768, 215 pC/N and 320 $^{\circ}C$ at 0.2 wt%${La}_2{O}_3$addition, respectively.

Effects of Titanium, Hafnium and Zircornium Alloying Elements on Microstructures and $D0_3{\leftrightarrow}B2$ Transition Temperature of Fe-30Al-5Cr Alloys (Fe-30Al-5Cr 합금의 미세조직 및 $D0_3{\leftrightarrow}B2$ 천이온도에 미치는 Ti, Hf 및 Zr의 첨가효과)

  • Kim, Sung-Su;Joo, Sung-Min;Oh, Seon-Hun;Kim, Kwan-Hyu;Choi, Dap-Chun
    • Journal of Korea Foundry Society
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    • v.21 no.1
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    • pp.15-23
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    • 2001
  • The changes in the microstructures and $D0_3{\leftrightarrow}B2$ transition temperature were investigated for Fe-30at.%AI-5at.%Cr alloy with the ordered $D0_3$, structure when Ti, Hf and Zr were added respectively. The addition of Cr has no effect on the microstructure. However, as the amount of Ti addition increased, the grain size became smaller. Addition of Ti+Hf, Ti+Zr and Ti+Hf+Zr also showed the similar effect. When 20at.% of Ti was added, the second phase precipitates on the substrate. The addition of Cr, Hf and Zr alone has no effect on $D0_3{\leftrightarrow}B2$ transition temperature. However, as the amount of Ti addition increased by 5, 10, 15 and 20at.%, the transition temperatures showed 929, 930, 960 and $930^{\circ}C$ respectively.

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The Effects of $SrTiO_3$ Addition on the Microstructure and Magnetic Properties of YIG (YIG ($Y_3$$Fe_5$O_{12}$)의 미세구조 및 자성 특성에 대한 $SrTiO_3$첨가 영향)

  • Jang, Hak-Jin;Yun, Seok-Young;Kim, Tae-Ok
    • Korean Journal of Materials Research
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    • v.11 no.3
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    • pp.203-206
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    • 2001
  • The effects of SrTiO$_3$ addition and sintering temperature on the microstructure and magnetic properties of yttrium iron garnet (YIG) were investigated. The lattice Parameter increasing of sintered YlG with small amount of SrTiO$_3$ addition was supposed to be substituted $Y^{+3}$, Fe$^{+3}$ ions to Sr$^{+2}$,Ti$^{+4}$ ions which are relatively large in ionic ranius. A YIG specimen sintered at 142$0^{\circ}C$ with 0.2mol% SrTiO$_3$ showed above 98% densification of theoretical density. Saturation magnetization (M$_s$) at room temperature decreased a little bit with increasing SrTiO$_3$, addition but no great chance. In addition, the coercivity (H$_c$) was almost not changed by sintering temperature.

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Effect of Ti addition on the fracture toughness of Al-Ti-B alloys synthesized by high energy ball milling and spark plasma sintering (고 에너지 볼 밀링과 SPS 성형에 의해 제조된 Al-Ti-B합금의 파괴인성에 미치는 Ti의 영향)

  • 김지희;김선진;김준기
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2003.11a
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    • pp.84-84
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    • 2003
  • The effects of Ti addition on microstructure and mechanical properties of (Al+Xat.%Ti)2at%B (X=0.5, 1, 2) fabricated by mechanical alloying and spark plasma sintering (SPS) were investigated. These alloys were prepared by high energy ball milling (attritor) and then fracture toughness was investigated by using a charpy impact tester. The SPS method was used to consolidate (Al+Xat.%Ti)fat.%B with the pressure of 50MPa. The powders were successfully consolidated to alloy which the theoretical density is 99%. It was confirmed that the fracture toughness of Al-Bat.% matrix composites was increased by the addition of Ti.

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The effect of g1ass frit arid BaWO$_4$ Addition Microwave Dielectric Prperties of BaTiO$_3$-3TiO$_2$ Ceramics (Glass 첨가 및 BaWO$_4$ 첨가에 따른 BaTiO$_3$-3TiO$_2$ 세라믹스의 고주파 유전 특성)

  • 윤중락;김지균;이헌용
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1998.06a
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    • pp.335-338
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    • 1998
  • The effect of glass flit addition on microwave dielectric properties of BaTiO$_3$-3TiO$_2$ ceramic was studied. Addition of glass frit to this system obtained sintered sample below sintering temperature 105$0^{\circ}C$. At BaTiO$_3$-3TiO$_2$+ g1ass frit 3wt% + BaWO$_4$6 wt%m, this ceramic showed excellent microwave properties of dielectric constant 34, Q$\times$f 8,100, temperature coefficient of resonant frequency 4 ppm/$^{\circ}C$ .

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