• 제목/요약/키워드: SHS method

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규소/질화규소 비가 자전연소합성공정을 이용한 다공질 질화규소 세라믹스의 미세구조와 특성에 미치는 영향 (Effect of Si/$Si_3N_4$ Ration on the Micro structure and Properties of Porous Silicon Nitride Prepared by SHS Method)

  • 김동백;박동수;한병동;정연길
    • 연구논문집
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    • 통권34호
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    • pp.131-138
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    • 2004
  • Porous silicon nitride ceramics were prepared by Self-propagating High Temperature Synthesis from silicon powder, silicon nitride powder and the pore-forming precursor. The microstructure, porosity and the flexural strength of the porous silicon nitride ceramics were varied according to the Si/$Si_3N_4$ ratio, size and amount of the pore-forming precursors. Some samples exhibited as high flexural strength as $162\pm24$ MPa. The high strength is considered to result from the fine pore size and the strong bonding among the silicon nitrid particles.

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Characterization of Nano-Tube Fibers Formed by Self-propagating High Temperature Synthesis

  • Choi, Y.
    • 한국분말야금학회:학술대회논문집
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    • 한국분말야금학회 2003년도 international symposium on advanced powder metallurgy
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    • pp.95-96
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    • 2003
  • Titanium carbide nano-tube and fibers were synthesized by self-propagating high temperature synthesis (SHS) method. The average diameters of the nano-tubes and nano-fibers are about 100 and 20 nm in diameter, respectively. the non-stoichiometric numbers of the titanium carbide determined by neutron diffractometry were 0.87 and 0.94.

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Al-N2와 Al-N2-AlN계에서 고온자전연소법에 의한 AlN 합성 (AlN preparation by Self-propagation High-temperature Synthesis (SHS) in Al-N2 and Al-N2-AIN system)

  • 이재령;이익규;안종관;김동진;안양규;정헌생
    • 한국분말재료학회지
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    • 제11권4호
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    • pp.294-300
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    • 2004
  • This study for preparation of aluminum nitride (AlN) with high purity was carried out by self-propagating high-temperature synthesis method in two different systems, $Al-N_{2}$ and $Al-N_{2}$-AlN, with the change of nitrogen gas pressure and dilution factor. On the occasion of $Al-N_{2}$ system, unreacted aluminum was detected in the product in spite of high nitrogen pressure, 10 MPa, This may be caused by obstructing nitrogen gas flow to inner part of molten and agglomerate of aluminum, formed in pre-heating zone. In $Al-N_{2}$-AlN system, AlN with a purity of 95% or ever can be prepared in the condition of $f_{Dil}\geq0.5$, $P_{N_{2}}\geq$ 1 MPa, and the purity can be elevated to 98% over in the condition of $f_{Dil}$ = 0.7 and $P_{N_{2}}$ = 10 MPa.

자체반응열 고온합성법에 의한 질화티타늄 합성에 관한 연구 (A Study on the Synthesis of Titanium Nitride by SHS(Self-propagating High-temperature Synthesis) Method)

  • 하호;김광래;이희철
    • 한국세라믹학회지
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    • 제30권12호
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    • pp.1096-1102
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    • 1993
  • Titanium nitride was synthesized by reacting Ti powder with nitrogen gas using SHS method. In this process, the effects of nitrogen pressure, dilution with TiN, or additiion of titanium hydride(TiH1.924) on the conversion of Ti to TiN were investigated. In particular, much effects were given to solve the problem of the conversion drop due to partial melting and subsequent sintering of Ti parciels, by controlling combustion temperature and combustion wave velocity via mixing Ti powder with TiN or/and TiH1.924. For the diluted titanium powders with TiN, the conversion close to 100% was resulted when the nitrogen pressure was over 8atm and with diluent content of 60wt%, and the self-propagating reaction was not sustained when the diluent content was higher than 60wt%. For samples mixed to be 55wt% in Ti component in the mixture of Ti, TiH1.924, and 45% TiN, the conversion was closed to 100% when the amount of titanium hydride added was over 7wt% and the nitrogen pressure was higher than 5atm. The combustion reaction, however, was not sustained when titanium hydride added was more than 10wt%.

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Experimental and theoretical studies on SHS column connection with external stiffening ring under static tension load

  • Rong, Bin;You, Guangchao;Zhang, Ruoyu;Ma, Xu;Quan, Xinxin
    • Steel and Composite Structures
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    • 제28권2호
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    • pp.167-177
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    • 2018
  • In order to investigate mechanical properties in the core area of Square Hollow Section(SHS) column connection with external stiffening ring, four specimens were tested under the static tension load. The failure modes, load-displacement curves and strain distribution were analyzed to study the mechanical properties and the load transfer mechanism of the core area of connections. The connections behave good ductility and load-bearing capacity under the static tension load. Parametric analysis was also conducted, in which the thickness of steel tube, extended width and thickness of the stiffening ring were considered as the parameters to investigate the effects on mechanical properties of the connections. Based on the experimental results, an analytical method for the bearing capacity of connection with external stiffening ring under the static tension load was proposed. The theoretical results and the experimental results are in good agreement, which indicates that the theoretical calculation method of the bearing capacity is advisable.

자전연소합성법에 의한 ZrB2 세라믹분말합성 및 NaCl의 영향 (Preparation of ZrB2 by Self-propagating Synthesis and Its Characteristics)

  • 김진성;;원창환
    • 한국재료학회지
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    • 제24권5호
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    • pp.255-258
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    • 2014
  • Zirconium boride is an artificial or which is rarely found in the nature. $ZrB_2$ is popular in the hard material industry because it has a high melting point, excellent mechanical properties and chemical stability. There are two known methods to synthesize $ZrB_2$. The first involves direct reaction between Zr and B, and the second is by reduction of the metal halogen. However, these two methods are known to be unsuitable for mass production. SHS(Self-propagating High-temperature Synthesis) is an efficient and economic method for synthesizing hard materials because it uses exothermic reactions. In this study, $ZrB_2$ was successfully synthesized by subjecting $ZrO_2$, Mg and $B_2O_3$ to SHS. Because of the high combustion temperature and rapid combustion, in conjunction with the stoichiometric ratio of $ZrO_2$, Mg and $B_2O_3$; single phase $ZrB_2$ was not synthesized. In order to solve the temperature problem, Mg and NaCl additives were investigated as diluents. From the experiments it was found that both diluents effectively stabilized the reaction and combustion regime. The final product, made under optimum conditions, was single-phase $ZrB_2$ of $0.1-0.9{\mu}m$ particle size.

조선시대 남성 분묘 출토 적삼 고찰 - 송효상(宋效商, 1430-1490), 송희종(宋喜從, 16C중후반)묘 출토 복식을 중심으로 - (Men's Single-layered $Chog{\breve{a}}ri$ in Joseon Dynastry -Focused on SongHyosang(1430-1490), SongHeejong(the late 1500s) tombs -)

  • 권준희;권영숙
    • 복식
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    • 제59권3호
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    • pp.131-144
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    • 2009
  • This study is about single-layered $Chog{\breve{a}}ri$ excavated from SongHyosang(宋效商, 1430-1490, SHS hereafter), SongHeeJong(宋喜從, the late 1500s, SHJ hereafter) tombs. There are 7 single-layered $Chog{\breve{a}}ris$ for men. We focus on comparison of their design and sowing method. 1. Design: Investigating collar, $Chog{\breve{a}}ris$ from SHS have MokpanGit and $Chog{\breve{a}}ris$ from SHJ have KalGit. KalGit has been seen from SHJ to 17th, 18th and 19th centuries. After the late 1500s, there is no MokpanGit single-laTered $Chog{\breve{a}}ri$ for men. Side panel under arm has various shapes(triangle, trapezoid, triangle+trapezoid) in 15th century. After the late 1500s, It changes into no side panel. Two $Chog{\breve{a}}ris$ with no side panel from SHJ reveals that the late 1500s is a period of transition. 2. Sewing method: First, researching lengthwise grainline of the fly, the left fly has lengthwise grainline outside In four, inside in three. The right fly has lengthwise grainline outside in just one, the others have lengthwise grainline inside. Compared with today's way, there is a great difference, but in those times there isn't an established rule. This is true of side panel under arm. The sewing method are backstitch, running stitch, and hemming. Researching the construction method of seam, in putting two selvages together, open seam and plain seam are used. In putting selvage and bias, bias and bias together, flat felled seam and french seam are used. This study shows that single-layered $Chog{\breve{a}}ri$ far men from 15C. to 16C. has changes of design such as collar(Git) and side panel undo. arm. But there is little change in sewing method.

알칼리 침출법을 통한 초경 공구의 재활용 및 자전연소합성법을 통해 제조된 나노급 탄화텅스텐 제조공정 연구 (Recycling of Hardmetal Tool through Alkali Leaching Process and Fabrication Process of Nano-sized Tungsten Carbide Powder using Self-propagation High-temperature Synthesis)

  • 강희남;정동일;김영일;김인영;박상철;남철우;서석준;이진영;이빈
    • 한국분말재료학회지
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    • 제29권1호
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    • pp.47-55
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    • 2022
  • Tungsten carbide is widely used in carbide tools. However, its production process generates a significant number of end-of-life products and by-products. Therefore, it is necessary to develop efficient recycling methods and investigate the remanufacturing of tungsten carbide using recycled materials. Herein, we have recovered 99.9% of the tungsten in cemented carbide hard scrap as tungsten oxide via an alkali leaching process. Subsequently, using the recovered tungsten oxide as a starting material, tungsten carbide has been produced by employing a self-propagating high-temperature synthesis (SHS) method. SHS is advantageous as it reduces the reaction time and is energy-efficient. Tungsten carbide with a carbon content of 6.18 wt % and a particle size of 116 nm has been successfully synthesized by optimizing the SHS process parameters, pulverization, and mixing. In this study, a series of processes for the high-efficiency recycling and quality improvement of tungsten-based materials have been developed.

니켈 나노입자가 흡착된 에너제틱용 고반응성 알루미늄 분말 합성 (Synthesis of Nickel Nanoparticle-adsorbed Aluminum Powders for Energetic Applications)

  • 김동원;권구현;김경태
    • 한국분말재료학회지
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    • 제24권3호
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    • pp.242-247
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    • 2017
  • In this study, the electroless nickel plating method has been investigated for the coating of Ni nanoparticles onto fine Al powder as promising energetic materials. The adsorption of nickel nanoparticles onto the surface of Al powders has been studied by varying various process parameters, namely, the amounts of reducing agent, complexing agent, and pH-controller. The size of nickel nanoparticles synthesized in the process has been optimized to approximately 200 nm and they have been adsorbed on the Al powder. TGA results clearly show that the temperature at which oxidation of Al mainly occurs is lowered as the amount of Ni nanoparticles on the Al surface increases. Furthermore, the Ni-plated Al powders prepared for all conditions show improved exothermic reaction due to the self-propagating high-temperature synthesis (SHS) between Ni and Al. Therefore, Al powders fully coated by Ni nanoparticles show the highest exothermic reactivity: this demonstrates the efficiency of Ni coating in improving the energetic properties of Al powders.