• Title/Summary/Keyword: SHS method

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A Study on the Synthesis of Titanium Hydride by SHS(Self-propagating High-temperature Synthesis) Method and the Preparation of Titanium Powder (SHS법에 의한 티타늄 수소화물 합성 및 티타늄 분말 제조에 관한 연구)

  • Ha, Ho;Park, Seung-Soo;Lee, Hee-Cheol
    • Applied Chemistry for Engineering
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    • v.5 no.2
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    • pp.263-273
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    • 1994
  • Titanium powder prepared by dehydrogenating the titanium hydride which is synthesized by reacting Ti-sponge (99.67%) with hydrogen using the self-propagating high-temperature synthesis method. In the synthesis of titanium hydride, the particle size of the product was found dependent on the amount of hydrogen incorporated into the titanium such that the particle size of titanium hydride decreased with increasing hydrogen pressure and after-burn time. In the dehydrogenation process, as the dehydrogenation time increase, the particle size of titanium powder increased due to partial melting and sintering of titanium particles.

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A Study on Adequacy of Audit Techniques and Advancement of Ship-Handling Simulation for Maritime Safety Audit (해상교통안전 진단 기술의 적정성 및 선박조종시뮬레이션 고도화)

  • Lee, Yun-Sok
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.17 no.4
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    • pp.391-398
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    • 2011
  • SHS(Ship-Handling Simulator) is virtual generation of vessel traffic situation under various environmental conditions. Recent, with the introduction of MSA(Maritime Safety Audit), SHS is being used as a key facility to determine the safety of navigation. However, the current audit techniques specified in the implementation guidance of MSA have been prepared by generalizing common procedures and evaluation methods used by institutions operating simulator systems. Therefore, they need to be reviewed and supplemented. This study analyzed the adequacy of current audit techniques based on the limitations and problems, then suggested the advanced scheme of SHS such as standardization of ship models, standard manoeuvring and evaluation method. The results of this research will contribute to improving the quantification and reliability of audit techniques used in the MSA as well as upgrading of the simulator system.

Fabrication of $TiB_2$-W Composite by SHS Method (SHS 법에 의한 $TiB_2$-W 복합재료 제조에 대한 연구)

  • 이형복;강석원;이재원;박원석
    • Journal of the Korean Ceramic Society
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    • v.37 no.9
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    • pp.915-920
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    • 2000
  • 합성과 동시에 소결이 이루어지는 HPCS법을 이용하여 TiB$_2$-W 복합체를 텅스텐의 함량 변화에 다라 제조하여 이 복합체의 미세구조 및 기계적 물성에 대하여 연구하였다. 이 연구 결과, 텅스텐의 함량증가에 따라 삼성분 붕화 화합물인 TiWB$_2$의 상이 증가하였으며, 이 상의 증가에 따라 기계적 물성이 향상되었다. 60 MPa의 압력과 130$0^{\circ}C$, 3000 A에서 소결한 TiB$_2$-30vol% W 복합체에서 상대밀도, 강도, 경도 값은 각각 97.2%, 411.5 MPa, 22.36 GPa로 가장 우수한 물성을 얻을 수 있었다.

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A Study on Synthesis and Characterization of $Ti_xZr_{1-x}C$ Solid-Solution by Self-propagation High Temperature Synthesis Method (SHS법에 의한 $Ti_xZr_{1-x}C$ 고용체의 합성 및 특성 연구)

  • 이형복;오유근;이성민
    • Journal of the Korean Ceramic Society
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    • v.34 no.7
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    • pp.731-737
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    • 1997
  • TixZr1-xC(0$0^{\circ}C$, 5.1 mm/sec respectively. The relative density, three point flexural strength, and the hardness of composites, which was sintered at 190$0^{\circ}C$ for 60 min by using hot-pressing under a pressure of 30 MPa, were 99%, 525 MPa and 24 GPa respectively.

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Study on Synthesis and Sintering Characterization of Ti-Si System Ceramics by Self-Propagating High Temperature Synthesis (SHS법에 의한 Ti-Si계 세라믹스의 합성 및 소결체의 특성에 관한 연구)

  • Kim, Do-Kyung;Park, Sung;Cho, Duk-Ho;Cho, Kurn;Lee, Hyung-Bock
    • Journal of the Korean Ceramic Society
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    • v.31 no.3
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    • pp.265-274
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    • 1994
  • Intermetallic Ti-Si system ceramics were synthesized from stochiometric mixtures of titanium and silicone powders in vacuum by Self-propagating High-temperature Synthesis(SHS). In each cases of Ti5Si3, Ti5Si4 and TiSi, and TiSi2 synthesis, 20wt% product dilution, direct ignition and SHS chemical furnace method were employed. The combustion modes, which were observed during the synthesis process by using the high speed camera, of Ti5Si3, Ti5Si4, TiSi, and TiSi2 exhibit spin, osciallatory, steady-state, and spin combustion, respectively. With increasing Ti/Si molar ratio an decrease of combustion velocities was found. From the results on the measurement of the flexural strength, the specimen hot pressed at 135$0^{\circ}C$ for 30 min using synthesized Ti5Si4 powders showed the highest flexural strength at 215 MPa.

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Effect of Si/α-Si3N4 Ratio on the Shape of Silicon Nitride Particles Produced by SHS Method

  • Kim, Min-Sung;Park, Dong-Soo;Han, Byung-Dong;Kim, Hai-Doo;Park, Chan
    • Journal of the Korean Ceramic Society
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    • v.39 no.3
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    • pp.217-221
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    • 2002
  • Si and ${\alpha}-Si_3N_4$ powder mixtures added with 3 wt% $Y_2O_3$ were reacted under 5 MPa nitrogen pressure. The reaction products contained ${\alpha}-Si_3N_4$ particles with elongated shapes. Length and width of the elongated grains were the maximum when the starting powder mixture of 50 wt% Si - 47 wt% ${\alpha}-Si_3N_4$ and 3 wt% $Y_2O_3$ was used. Aspect ratio of the elongated grains were between 4.4 and 5. When the starting powder mixture contained 70 wt% Si, large particles with irregular shapes appeared. Meanwhile, the reaction did not proceed when the starting powder mixture contained 30 wt% Si and less. The SHS product was easy to crush and the elongated particles obtained from the starting powder mixtures of 40 wt% Si - 57 wt% ${\alpha}-Si_3N_4$ - 3 wt% $Y_2O_3$ and 50 wt% Si - 47 wt% ${\alpha}-Si_3N_4$ - 3 wt% $Y_2O_3$ were good candidates for the seeds.

Synthesis of LiMn2O4 Powders Using Li-Ion Secondary Battery by SHS Process (SHS합성법에 의한 리튬이온이차전지용 정극활물질 LiMn2O4 의 제조)

  • Jang, Chang-Hyun;Nersisyan, Hayk;Kim, Jung-Han;Won, Chang-Whan
    • Journal of the Korean Ceramic Society
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    • v.42 no.7 s.278
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    • pp.503-508
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    • 2005
  • A simple and effective method for the synthesis of LiMn$_{2}$O$_{4}$ powder as a cathode material for lithium secondary battery is reported. Micrometer size LiMn$_{2}$O$_{4}$ was prepared by combustion synthesis technique employing initial mixture of l.l LiNO$_{3}$ -1.3Mn-0.7MnO$_{2}$-1NaCl composition. Parametric study of the combustion process including molar ratio of Mn/MnO$_{2}$ and NaCl concentration were carried out under air atmosphere. The combustion products obtained were additionally heat treated at the temperature 900$^{\circ}C$ and the washed by distilled water. The results of charging-discharging characteristics revealed that LiMn$_{2}$O$_{4}$ cell synthesized in the presence of NaCl had a high capacity and much better reversibility than one formed without NaCl An approximate chemical mechanism for LiMn$_{2}$O$_{4}$ formation is proposed.

Synthesis and Characteristic of BaMgAl10O17:Eu2+ Phosphor by SHS (자전연소 합성법을 통한 BaMgAl10O17:Eu2+ PDP용 청색형광체의 합성과 특성)

  • Lee Jong Eun;Kim Byeong Beom;Park Yeong Cheol;Won Chang Whan
    • Korean Journal of Materials Research
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    • v.14 no.12
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    • pp.885-888
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    • 2004
  • $BaMgAl_{10}O_{17}:Eu^{2+}$ for PDP blue phosphor was synthesized using SHS(Self-propagating High temperature Synthesis) method. While Al metal powder was oxidized in this combustion, $Eu_{2}O_3$ was reduced to Eu2+. Therefore the mole ratio of $Al/Al_{2}O_3$ is one of the most important variable of the reaction. When $Al/Al_{2}O_3$ is 2.5/3.75, it has not only appropriate temperature and reaction velocity, but also excellent luminescent property. The sample synthesized in this system has similar characteristics comparing to sample using conventional solid-state reaction.