• Title/Summary/Keyword: Sintering characteristics

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A study on the effects of compacting pressure on the electrical & sintering characteristics of Cu25Cr contact material (Cu25Cr 접점재료의 성형압력에 따른 소결 및 전기적 특성에 관한 연구)

  • 연영명;박홍태;오일성;이경행
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.07a
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    • pp.1065-1068
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    • 2001
  • Effects of compacting pressure on the electrical and sintering characteristics of Cu25Cr contact material have been investigated. Cu25Cr contact materials were prepared by solid and liquid-phase sintering methods varying compacting pressure. Influence of compacting pressure on electrical characteristics were investigated in the cylindrical stainless-steel vessel using L-C resonant circuit. The physical and electrical properties of solid-phase sintered Cu25Cr material were found to be improved by increased compacting pressure. On the other hand, it was found that compacting pressure had little influence in case of liquid-phase sintered Cu25Cr material. After conditioning, contact resistance of Cu25Cr material was decreased regardless of compacting pressure. With increased compacting pressure, interrupting ability was shown to be increased.

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Electrical Characteristics of Piezoelectric Transformer using Low Temperature Sintering PCW-PMN-PZT Ceramics (저온소결 PCW-PMN-PZT 세라믹스를 적용한 압전변압기의 전기적 특성)

  • Chung, Kwang-Hyun;Yoo, Ju-Hyun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.19 no.4
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    • pp.350-356
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    • 2006
  • In this study, piezoelectric transformer was manufactured at the sintering temperature of $950^{\circ}C$, and then the feasibility of application to low temperature sintering piezoelectric transformers was investigated by evaluating the electrical characteristics of it. The voltage ratio of piezoelectric transformer showed the maximum value at the resonant frequency of input part, and increased according to the increase of load resistance. The output power and efficiency of piezoelectric transformer showed the superior properties when the output impedance of it coincides with the load resistance. Piezoelectric transformer manufactured at the low temperature of $950^{\circ}C$ showed the heat generation less than $20^{\circ}C$ at the output power of 30 W, and stable driving characteristics.

Clamping Voltage Characteristics of ZPCCE-Based Varistors with Sintering Temperature (소결온도에 따른 ZPCCE계 바리스터의 제한전압특성)

  • 남춘우;박종아;김명준;유대훈
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.8
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    • pp.835-839
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    • 2004
  • The surge characteristics of ZnO varistors consisting of $ZnO-{Pr}_6{O}_11-CoO-{Cr}_2{O}_3-{Er}_2{O}_3$ceramics were investigated at various sintering temperatures. As sintering temperature raises, the varistor voltage was decreased from 341.2 to 223.1 V/mm, the nonlinear exponent was decreased from 64,9 to 44.1. On the other hand, the leakage current exhibited a minimum(0.64 $\mu$A) at 134$0^{\circ}C$, The clamping capability was slightly deteriorated with increasing sintering temperature. On the whole, the ZPCCE-based ZnO varistors exhibited good clamping voltage characteristics as exhibiting the clamping voltage ratio of 1.85 ∼ 1.92 approximately at surge current of 100 A.

Effect of Compacting Pressure on Sintering Characteristics of Commercial 2xxx Series Al Alloy Powders (성형압의 변화가 상용 2xxx AI 합금계 혼합분말의 소결특성에 미치는 영향)

  • 김대건;민경호;장시영;김영도
    • Journal of Powder Materials
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    • v.9 no.2
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    • pp.116-123
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    • 2002
  • The characteristics of two commercial 2xxx series Al alloy powders, AMB2712 and 201AB, were evaluated and their compacting and sintering characteristics were discussed in tems of compacting pressure. The particle shapes of both two powder mixtures were irregular and their particle size distributions were broad. The compactibility of AMB2712 was superior to that of 201AB because of better fluidity. The sintered density was higher than the green density at low compacting pressure, however, it was lower than the green density when the samples were compacted at higher pressure due to the selling during sintering. The sintered density was alomost the same as the green density at the "homogeneous deformation" stage. It was observed that pores were created at the triple points due to the rapid diffusion of Cu in Al. Cu in Al.

Fluid-flow Characteristics of Flue-gas-recirculation System in Sintering Plant (소결로 배기가스 재순환 시스템 내의 유체유동 특성 연구)

  • Moon, Chanhee;Kim, Hyun Dong;Kim, Kyung Chun
    • Journal of the Korean Society of Visualization
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    • v.16 no.2
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    • pp.7-15
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    • 2018
  • The fluid-flow characteristics of flue-gas-recirculation (FGR) system can have a significant effect on system efficiency of a sintering plant. The flow characteristics in the system were investigated. A sintering plant with FGR system was modeled. Numerical visualization was performed and flow characteristics were analyzed. Characteristics of the flow distribution of the branch ducts, the inflow of air into the recirculating hood, and the flow in the hood were discussed. Based on the results three suggestions were proposed: (1) distribution of branch duct flowrate upstream, (2) installation of external air ducts in the hood, and (3) installation of baffles at the hood corners. The suggestions were tested numerical and experimental visualization methods. The suggestions were effective and confirmed to be applicable to the actual sinter plant.

Evaluation on Mechanical Properties of Tungsten by Sintering Additive Content (소결첨가재에 의한 텅스텐의 기계적 특성평가)

  • Lee, Sang-Pill;Lee, Jin-Kyung
    • Journal of the Korean Society of Industry Convergence
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    • v.25 no.4_2
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    • pp.621-626
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    • 2022
  • Tungsten is a high melting point metal unlike other steel materials, and it is difficult to manufacture because of its high melting temperature. In this study, pressure sintering process method was applied to manufacture the tungsten materials at low temperature. Therefore, it is necessary to densify the sintered material by using a sintering additive. Studies have been conducted on how the amount of titanium for sintering tungsten affects the mechanical properties of tungsten in this study. In order to secure the densification mechanism of tungsten powder during the sintering process, the characteristics of the sintered tungsten material according to the change of titanium content were evaluated. It was investigated the relationship between sintering parameters and mechanical properties for densification of microstructures. The sintered tungsten materials according to sintering additive content showed high sintered density (about 16.31g/cm3) and flexural strength (about 584 MPa) when the content of sintering additive was 3 wt%. However, as the content of the sintering additive increases, mechanical property of flexural strength is decreased, and the porosity is increased due to the heterogeneous sintering around titanium.

Influence of Sintering Condition on Characteristics of $\alpha$-SiC Ceramics ($\alpha$-SiC 소결체의 특성에 미치는 소성조건의 영향)

  • 정두화;김인술;김효준
    • Journal of the Korean Ceramic Society
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    • v.28 no.10
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    • pp.824-830
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    • 1991
  • $\alpha$-SiC(B; 0.4 wt, C; 3 wt%) was sintered in Ar atmosphere from 205$0^{\circ}C$ to 220$0^{\circ}C$ by means of pressureless sintering and gas pressure sintering in order to find optimum sintering condition of $\alpha$-SiC. Mechanical properties and microstructures of sintered bodies were investigated according to sintering method. The effect of sintering condition on sinterability of $\alpha$-SiC was also examined by using the dilatometer. 97.5% and 98.8% of theoretical density were obtained from pressureless sintering and gas pressure sintering of $\alpha$-SiC powder, respectively. And modulus of rupture was measured as 270~350 MPa and 420 MPa respectively.

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Structural and ferroelectric characteristics of sol-gel $Pb(Zr_{1-x}Ti_x)O_3$ thin films according to the sintering conditions and Zr/Ti mol% (소성 조건과 Zr/Ti 몰비에 따른 졸겔 $Pb(Zr_{1-x}Ti_x)O_3$ 박막의 구조 및 강유전 특성)

  • 김준한;윤현상;박정흠;장낙원;박창엽
    • Electrical & Electronic Materials
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    • v.9 no.8
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    • pp.836-850
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    • 1996
  • In this study, we have analyzed structural analysis and measured ferroelectric characteristics of PZT thin films prepared by sol gel process with different sintering conditions and different Zr/Ti mot%. When the Zr mot% of PZT thin film was increased, it was found that the remanent. polarization and coercive field were decreased and increased, respectively. Also, the maxium dielectric constant of PZT(50/50) thin film was 786.8. We got double hysteresis(anti-fcrroelectric) curve from PbZrO$_{3}$ thin film. As heating rate goes up, pyrochlore phase of PZT thin film was decreased and dielectric and ferroelectric characteristics were improved. As a result of variation of sintering temperature and time 500.deg. C-800.deg. C and 5 sec.-8 hours, respectively, we got optimal sintering temperature and time. The optimium sintering temperature and time of conventional furnace method and rapid thermal processing method were 650.deg. C-700.deg. C for 30-60 minutes and 700.deg. C/20 seconds-2 minutes, respectively.

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Clamping Voltage Characteristics and Accelerated Aging Behavior of CoCrTb-doped Zn/Pr-based Varistors with Sintering Temperature

  • Nahm, Ghoon-Woo
    • Transactions on Electrical and Electronic Materials
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    • v.10 no.4
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    • pp.125-130
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    • 2009
  • The clamping voltage characteristics and accelerated aging behavior of CoCrTb-doped Zn/Pr-based varistors were investigated for different sintering temperatures. The best clamping voltage characteristics were obtained for the varistors sintered at $1330^{\circ}C$, with a clamping voltage ratio (K) of 1.63 at a surge current of 5 A and 1.75 at a surge current of 10 A. The varistors sintered at $1330^{\circ}C$ exhibited the highest stability, with -0.1% in $%{\Delta}E_{1\;mA}$, -0.2% in $%{\Delta}{\alpha}$, and +15.5% in $%{\Delta}J_L$ for E-J characteristics under a stress state of 0.90 $E_{1\;mA/120^{\circ}C$ /24 h. Furthermore, it exhibited $%{\Delta}{\varepsilon}_{APP}$' of -0.7% and $%{\Delta}tan{\delta}$ of +5.7% for dielectric characteristics under the same stress state.