• Title/Summary/Keyword: Powder Compacts

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Fabrication and Property Evaluation of Cu-Mn Compacts for Sputtering Target Application by a Pulsed Current Activated Sintering Method (펄스전류활성소결법을 이용한 스퍼터링 타겟용 Cu-Mn 소결체 제조 및 특성평가)

  • Jang, Jun-Ho;Oh, Ik-Hyun;Lim, Jae-Won;Park, Hyun-Kuk
    • Journal of Powder Materials
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    • v.23 no.1
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    • pp.1-7
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    • 2016
  • Cu-Mn compacts are fabricated by the pulsed current activated sintering method (PCAS) for sputtering target application. For fabricating the compacts, optimized sintering conditions such as the temperature, pulse ratio, pressure, and heating rate are controlled during the sintering process. The final sintering temperature and heating rate required to fabricate the target materials having high density are $700^{\circ}C$ and $80^{\circ}C/min$, respectively. The heating directly progresses up to $700^{\circ}C$ with a 3 min holding time. The sputtering target materials having high relative density of 100% are fabricated by employing a uniaxial pressure of 60 MPa and a sintering temperature of $700^{\circ}C$ without any significant change in the grain size. Also, the shrinkage displacement of the Cu-Mn target materials considerably increases with an increase in the pressure at sintering temperatures up to $700^{\circ}C$.

Effect of heating Rate on the Microstructural Evolution during Sintering of PZT Ceramics (PZT 요업체의 소결과정 중 승온속도가 미세조직에 미치는 영향)

  • 박은태;김정주;조상희;김도연
    • Journal of the Korean Ceramic Society
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    • v.27 no.8
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    • pp.1020-1026
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    • 1990
  • The effect of heating rate on the microstructural evolution during sintering of PZT ceramics has been investigated. In case of PZT powder compacts containing excess of PbO, fast heating caused incomplete rearrangement of solid grains in a liquid, resulting in lower density and inhomogeneous pore shape ; on contrary, slow heating resulted in better densification. In contrast, in case of compacts without excess PbO, the densification was enhanced by fast heating due to suppression of the grain growth.

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Rapid Heating of Ultrafine $Si_3N_4$ Powder Compacts under the Controlled Thermograms (가열이력 제어에 의한 $Si_3N_4$ 미분말 시편의 급속가열)

  • 이형직
    • Journal of the Korean Ceramic Society
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    • v.30 no.3
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    • pp.181-188
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    • 1993
  • The sintering and renitridation behaviors of ultrafine Si3N4 powder compacts, which were heavily oxidized and/or free-Si rich, were investigated with particular attentiion to microstructures. The specimens were heated without restoring to additives and pressure by controlling heating process attained a Xe image apparatus. The effect of particle size, free-Si contents, decomposition and renitridation, were investigated. When fired to 1$650^{\circ}C$ within 15 sec and then immediately held at 135$0^{\circ}C$ for 10min N2 atmosphere, significant densification took place in the limited region, in addition to decreasing oxygen contents to less than 0.3wt%. On the other hand, specimens decomposed due to overheating at the initial stage were rapidly renitridated at the relatively lower temperature of the holding stage. And, then, the activation energy for the renitridation was calculated to be 49kcal/mole.

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Oxygen Removal during Sintering of Steels Prepared from Cr-Mo and Mo Prealloyed Powders

  • Danninger, Herbert;Xu, Chen;Lindqvist, Bjorn
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09b
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    • pp.814-815
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    • 2006
  • The removal of oxygen during sintering by carbothermic reduction was studied for steel compacts Fe-Cr-Mo-C and Fe-Mo-C prepared from prealloyed powders. The compacts were prepared by pressing at 600 and 1000 MPa and sintering at 1100 and $1300^{\circ}C$ in vacuum. It showed that for the Cr-Mo steel, deoxidation strongly depends on the sintering temperature, in contrast to the plain Mo steel; at $1300^{\circ}C$ very low oxygen levels were measured with the standard density compact while at high density still significant oxygen is contained. This indicates inhibition of final deoxidation by pore closure, but apparently without adverse effect on the mechanical properties.

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TiB2-Cu Interpenetrating Phase Composites Produced by Spark-plasma Sintering

  • Kwon, Young-Soon;V. Dudina, Dina;I. Lomovsky, Oleg;A. Korchagin, Michail;Kim, Ji-Soon
    • Journal of Powder Materials
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    • v.10 no.3
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    • pp.168-171
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    • 2003
  • Interpenetrating phase composites of $TiB_2$-Cu system were produced via Spark-Plasma Sintering (SPS) oi nanocomposite powders. Under simultaneous action of pressure, temperature and electric current titanium diboride nanoparticles distributed in copper matrix move, agglomerate and form a fine-grained skeleton. Increasing SPS-temperature and he]ding time promote densification due to local melting of copper matrix When copper melting is avoided the compacts contain 17-20% porosity but titanium diboride skeleton is still formed representing the feature of SPS . High degree of densification and formation of titanium diboride network result in increased hardness of high-temperature SPS-compacts.

Influence of Machining on Magnetic Properties of Soft Magnetic Composites

  • Igarashi, Kazunori;Miyahara, Masahisa;Morimoto, Koichiro
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09b
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    • pp.1175-1176
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    • 2006
  • Influences of machining on magnetic properties of soft magnetic composites (SMC's) with addition of two kinds of binder, i.e., organic binder and inorganic one, were investigated. Machining does not affect DC magnetic properties of the SMC compacts. This can be ascribed to their particular structure in which the ironpowder particles are highly isolated by the binder. On the other hand, decrease in resistivity and resultant increase in eddy current loss was confirmed in the machined compacts containing inorganic binder. It is supposed that the brittleadditive binder existing between the iron particles is partly broken, and iron-to-iron contact is formed on the machined surface.

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Synthesis and Sintering of Cordierite from Metla Alkoxides (II) Sintering (금속 Alkoxide로부터 Cordierite 분말의 합성 및 소결에 관한 연구 (II))

  • 한문희;박금철
    • Journal of the Korean Ceramic Society
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    • v.27 no.6
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    • pp.777-782
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    • 1990
  • The sintering behavior of cordierite powders synthesized using a sol-gel method of metal alkoxides Si(OC2H5)4, Al(OC3H71)3 and Mg(OC2H5)2 was investigated. Densification of the powder compacts fabricated using the precursor powders calcined at 900$^{\circ}C$ for 2hrs was improved over the sintering temperature range of 800 to 980$^{\circ}C$. The powder compacts, fabricated using the calcined precursor powders and sintered at 1300$^{\circ}C$ for 2hrs, showed relative density of 97-98%, 3-point bending strength of 120-140Mpa, KIC of 2.4-3.7 Mpam1/2, and thermal expansion coefficient of 1.48-1.66${\times}$10-6/$^{\circ}C$.

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Motion of WC Grains in the Liquid Matrix during Liquid Phase Sintering of WC-Co Alloys (WC-Co계의 액상소결시 코발트 액상 내에서 WC 입자의 움직임)

  • 김소나
    • Journal of Powder Materials
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    • v.3 no.3
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    • pp.196-200
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    • 1996
  • The dispersion of WC grains Into the interior of an eutectic liquid has been studied by superimposing the eutectic WC-85wt.%Co liquid on the top surface of presintered WC-l0wt.%Co alloy compacts. The heavy WC grains diffused into the interior of liquid from the WC-l0wt.%Co compacts. According to increasing the treating temperatures and times, the dispersion distance from WC-l0wt.%Co substrates increased. The fine WC grains diffused into the liquid faster than the coarse WC grains. The high microstructural stability of WC-Co alloys having the heavier WC grains dispersed in a lighter Co-rich liquid was attributed to Brownian motion of WC grains in liquid. The motion of WC grains in the liquid appears to be same with the colloid(the disperse phase) in a dispersing medium. The dihedral angle of 0 degree of WC-Co at. toy seems one of key parameters, which enables the WC-Co alloys to have high structural stability without settling the WC grains during liquid phase sintering.

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