• Title/Summary/Keyword: 자전연소합성법

Search Result 48, Processing Time 0.023 seconds

Reaction Parameters on the Reactivity in the Preparation of B4C by SHS (자전연소합성법에 의한 B4C분말의 제조에 있어 반응성에 대한 반응변수의 고찰)

  • Shin, Chang-Yun;Yun, Ki-Seok;Park, Yeong-Cheol;Hayk, Nersisyan;Won, Chang-Whan
    • Journal of the Korean Ceramic Society
    • /
    • v.42 no.1
    • /
    • pp.22-27
    • /
    • 2005
  • The preparation of B4C by SHS in $B_{2}O_{3}-Mg-C$ system was investigated in this study. In the preparation of B4C, the effect on reactivity and reaction products of the initial pressure of inert gas in reactor, the content of Mg and C in mixture was investigated. The minimum initial pressure of inert gas in reactor for SHS reaction in this system was 25 atm, and as the pressure increased, the concentration of unreacted Mg decreased and combustion temperature increased. At the initial inert gas pressure in reactor of 25 atm, the optimum composition for the preparation of pure B4C was $2B_{2}O_{3}+6.3Mg +0.94C$. The B4C synthesized in this condition had an irregular shape and the particle size of $1\~3{\mu}m$.

Cycling Properties of 80wt% AB2-15wt% Mg-5wt% Mm Metal Hydride made by Hydriding Combustion Synthesis (자전연소합성법으로 제조한 80wt% AB2-15wt% Mg-5wt% Mm 금속수소화물의 cycling특성)

  • Hur, Tae-Hong;Han, Jeong-Seb
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.22 no.5
    • /
    • pp.634-640
    • /
    • 2011
  • The effect of cycling on the absorption and desorption characteristics of the 80 wt% $AB_2$-15 wt% Mg-5 wt% Mm system was investigated. The material was made by Hydrogen Combustion Synthesis. The cycling experiment was performed at 298 K, 30 atm for 15 min. During the reaction time, the amount of absorption was fully desorbed. After the full activation, the hydrogen storage capacity was 1.57 wt% and the capacity was maintained until 50 cycles. And the reaction rate does not change with an increase in the number of cycles. This material has good durability and reversible feature.

Preparation and thermodynamics consideration of MgO-Al spinel by self-propagation high- temperature synthesis (자전고온연소합성법에 의한 MgO-Al 스피넬 제조 및 열역학적 고찰)

  • Byun, Hun-Soo;Choi, Tae-Hyun
    • Journal of the Korean Crystal Growth and Crystal Technology
    • /
    • v.8 no.4
    • /
    • pp.573-580
    • /
    • 1998
  • Self-propagating high temperature synthesis (SHS) technique was used to synthesize the spinel phase of $MgAl_2O_4$ from MgO and Al powder. Thermit reaction products of MgO and Al, The reaction products were heat treated at the temperature $800^{\circ}C$ preheating. Processing factors such as DTA/TG, combustium product and maxium temperature, synthesis of MgO and Al from "$MgO+2Al+3/2O_2$\rightarrow$MgAl_2O_4$". An activation energy (${\Delta}H^{\circ}$)-264.8 kcal/mol and reaction of maxium temperature 5634 K was calculated to form a $MgAl_2O_4$ spinel from unreacted materials. Pellet were increased volume 6% after thermit reaction. reaction.

  • PDF

Preparation of BaTiO3 Powder in $BaO2-TiO2-Reduction Agent-PSCA (Particle Size Control Agent) System by SHS and Its Dielectric Properties (B3O2-TiO2-환원제-입자제어제계에서 자전연소합성법에 의한 BaTiO3분말의 제조 및 유전특성)

  • Yun, Ki-Seok;Lim, Sung-Jae;Nersisyan, Hayk;Won, Chang-Whan
    • Journal of the Korean Ceramic Society
    • /
    • v.41 no.11
    • /
    • pp.842-850
    • /
    • 2004
  • We have investigated on the preparation of BaTiO$_3$ powder at the system of BaO$_2$-TiO$_2$-Reduction ag.-PSCA by SHS. C and Mg were used as reduction agent, and NaCl was used as PSCA (Particle Size Control Agent). The effects of the various reduction agent and its concentration, particle size control agent, reaction mixture mass on the product in the preparation of BaTiO$_3$ powder at the optimum system by SHS were investigated. The optimum conditions for reaction system and composition were BaO$_2$+TiO$_2$+0.11 Mg +0.2C+0.75NaCl in the As atmosphere. NaCl as PSCA showed the effect of controlling the particle size of product as well as the combustion temperature. The particle size of BaTiO$_3$ synthesized at the optimum condition was about 0.5 ${\mu}{\textrm}{m}$. And as the mixture mass for the reaction was increased, the more stable combustion wave appeared. We have conducted the sintering experiment at the temperature of 130$0^{\circ}C$, the time of 2 h and the atmosphere of air to measure the dielectric properties of BaTiO$_3$ synthesised in this work, and the sample sintered in this condition showed 2,290 of dielectric constant at 10$0^{\circ}C$ and 13,890 at curie point (129$^{\circ}C$).