• Title/Summary/Keyword: SHS process

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A Study on Self-Propagating High-Temperature Synthesis of TiC-Ni-Mo Based Cermet (SHS공정에 의한 TiC-Ni-Mo 분말 합성 및 소결체 제조)

  • 송인혁;전재호;한유동
    • Journal of the Korean Ceramic Society
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    • v.35 no.7
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    • pp.749-756
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    • 1998
  • TiC-Ni and TiC-Ni-Mo cermet powders were produced by Self-propagating High temperature Synthesis (SHS) process. The cooling rate of synthesized powders were controlled by using the V-shaped copper jig and the carbide size decreased with increasing the cooling rate I. e decreasing the width of copper jig Round shape carbide particles were produced after SHS reaction in TiC-Ni as well as TiC-Ni-Mo powders. Local segregation of Mo rich phases was observed in SHS powder of TiC-Ni-Mo and the uneven dis-triobution of Mo promoted the faster growth rate of carbide particles during sintering compared to the same composition specimen with commercial TiC powder. Howogeneous microstructure of TiC-Ni-Mo cermet was obtained when the elemental Mo powder was mixed with the SHS powder of TiC-Ni.

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Synthesis and Characteristics of LiCoO2 Powders Prepared by SHS Process (자전연소합성법을 이용한 리튬이차전지용 양극활물질 LiCoO2의 제조 및 특성)

  • ;;;Hayk H. Nersisyan
    • Journal of the Korean Ceramic Society
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    • v.41 no.5
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    • pp.388-394
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    • 2004
  • LiCoO$_2$ as the cathode activity material for lithium secondary battery was prepared from a homogeneously mixed powder of LiNO$_3$/Co by SHS process under argon gas. The characteristics of powder including electrochemical properties were investigated according to various reaction conditions. The reaction temperature/velocity and the size of LiCoO$_2$ were controlled by Li/Co molar ratio and a cooling rate of the specimen, respectively. The maximum discharge capacity was 145 mAh/g on 1.05 Li/Co molar ratio and the relatively stable cycling characteristic with 6.4% of capacity fading was obtained after 10th charging-discharging test.

Mechanical Properties of 2024/(Al2O3.SiC)p Composite Reinforced with Al2O3.SiC Particle Prepared by SHS Process (자전연소법으로 제조한 Al2O3.SiC 입자로 보강된2024/(Al2O3.SiC)p 복합재료의 기계적특성)

  • 맹덕영
    • Journal of Powder Materials
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    • v.7 no.1
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    • pp.35-41
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    • 2000
  • Al2O3$.$SiC particle was prepared was prepared by the self-propagting high temperature sYthesis(SHS) process from a mixture of SiO2, Al and C powders, The fabricated Al2O3$.$SiC particle was applied to 2024Al/(Al2O3$.$SiC)pcomposite as a reinforcement. Aluminum matix composites were fabricares by the powder extrusion method using the synthesized Al2O3$.$SiC particle and commercial 2024Al powder. Theoptimum preparation conditions for Al2O3$.$SiC partticle by SHS process were described. The influence of the Al2O3$.$SiC voiume fraction on the mechanical was composite was also discussed. Despite adiabatic temperature was about 2367K, SHs reaction was completed not by itself, but by using pre-heating. Mean particle size of final particle synthesized was 0.73 ${\mu}$m and most of the particle was smaller than 2${\mu}$m. Elastic modulus and tensile strength of the composite increased with increase the volume fraction of reinforcement but, tensile strength depreciated at 30 vol% of reinforcement.

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Preparation of WC Powders by SHS Process in the Presence of Alkali Salts (자전연소합성법에서의 알칼리염을 이용한 WC 분말의 제조)

  • Won, Hyung-Il;Nersisyan, Hayk;Won, Chang-Whan
    • Journal of the Korean Ceramic Society
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    • v.44 no.3 s.298
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    • pp.152-156
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    • 2007
  • Tungsten carbide powder was synthesized by SHS (self-propagating high-temperature synthesis). Except $WO_{3}$, each concentration of raw material ($WO_{3},\;Mg,\;NaCl,\;Na_{2}CO_{3},\;C$) was investigated. Final product was characterized by XRD and SEM. X-ray data demonstrated that the $NaCl+Na_{2}CO_{3}$ combined mixture has superiority in the WC formation process. Single phase and submicrometer WC powder was synthesized at the temperature below $1600^{\circ}C$. The role of sodium salts in combustion process was discussed, and chemical mechanism of WC formation was proposed. WC powder prepared by salt-assisted combustion synthesis has a size $0.2{\sim}3\;{\mu}m$ and low agglomeration degree.

Cleaning System Design using Supper Heating Steam (과열 수증기를 이용한 세정 시스템 설계)

  • Cho, Do-Hyeoun
    • 전자공학회논문지 IE
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    • v.48 no.2
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    • pp.47-51
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    • 2011
  • In this paper, we propose the cleaning process system to remove micro-particles, various impurities, unnecessary residues, etc. for liquid crystal display manufacturing processes. This system is structured with cleaning, rinse and drying process using the chemical cleaning of alkaline water and the physical cleaning of SHS(supper heating steam). And we shows cleaning effects of alkaline water and remove effects of SHS.

Formation of Fe Aluminide Multilayered Sheet by Self-Propagating High-Temperature Synthesis and Diffusion Annealing (고온자전반응합성과 확산 열처리를 이용한 FeAl계 금속간화합물 복합판재의 제조)

  • Kim, Yeon-Wook;Yun, Young-Mok
    • Korean Journal of Materials Research
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    • v.18 no.3
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    • pp.153-158
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    • 2008
  • Fe-aluminides have the potential to replace many types of stainless steels that are currently used in structural applications. Once commercialized, it is expected that they will be twice as strong as stainless steels with higher corrosion resistance at high temperatures, while their average production cost will be approximately 10% of that of stainless steels. Self-propagating, high-temperature Synthesis (SHS) has been used to produce intermetallic and ceramic compounds from reactions between elemental constituents. The driving force for the SHS is the high thermodynamic stability during the formation of the intermetallic compound. Therefore, the advantages of the SHS method include a higher purity of the products, low energy requirements and the relative simplicity of the process. In this work, a Fe-aluminide intermetallic compound was formed from high-purity elemental Fe and Al foils via a SHS reaction in a hot press. The formation of iron aluminides at the interface between the Fe and Al foil was observed to be controlled by the temperature, pressure and heating rate. Particularly, the heating rate plays the most important role in the formation of the intermetallic compound during the SHS reaction. According to a DSC analysis, a SHS reaction appeared at two different temperatures below and above the metaling point of Al. It was also observed that the SHS reaction temperatures increased as the heating rate increased. A fully dense, well-bonded intermetallic composite sheet with a thickness of $700\;{\mu}m$ was formed by a heat treatment at $665^{\circ}C$ for 15 hours after a SHS reaction of alternatively layered 10 Fe and 9 Al foils. The phases and microstructures of the intermetallic composite sheets were confirmed by EPMA and XRD analyses.