- Fabrication and Thermoelectric Properties of Carbon Nanotube/Bi2Te3 Composites
-
Kyung-Tae Kim, Kyeong-Mi Jang, Kyong-Ju Kim, Gook-Hyun Ha
-
J Korean Powder Metall Inst. 2010;17(2):107-112.
-
DOI: https://doi.org/10.4150/KPMI.2010.17.2.107
-
-
 Abstract
 PDF
- Carbon-nanotube-embedded bismuth telluride (CNT/Bi_2Te_3) matrix composites were fabricated by a powder metallurgy process. Composite powders, whereby 5 vol.% of functionalized CNTs were homogeneously mixed with Bi_2Te_3 alloying powders, were successfully synthesized by using high-energy ball milling process. The powders were consolidated into bulk CNT/Bi_2Te_3 composites by spark plasma sintering process at 350°C for 10 min. The fabricated composites showed the uniform mixing and homogeneous dispersion of CNTs in the Bi_2Te_3 matrix. Seebeck coefficient of CNT/Bi_2Te_3 composites reveals that the composite has n-type semiconducting characteristics with values ranging -55;µV/K to -95;µV/K with increasing temperature. Furthermore, the significant reduction in thermal conductivity has been clearly observed in the composites. The results showed that CNT addition to thermoelectric materials could be useful method to obtain high thermoelectric performance.
- Synthesis of TiB2 Dispersed Cu Matrix Composite Material by the Combination of the Mechanical Milling and Plasma Activated Sintering Process
-
Kyong-Ju Kim, Gil-Geun Lee, Ik-Min Park
-
J Korean Powder Metall Inst. 2007;14(5):292-297.
-
DOI: https://doi.org/10.4150/KPMI.2007.14.5.292
-
-
Abstract
PDF
- The present study was focused on the synthesis of a TiB_2 dispersed copper matrix composite material by the combination of the mechanical milling and plasma activated sintering processes. The Cu/TiB_2 mixed powder was prepared by the combination of the mechanical milling and reduction processes using the copper oxide and titanium diboride powder as the raw material. The synthesized Cu/TiB_2 mixed powder was sintered by the plasma activated sintering process. The hardness and electric conductivity of the sintered bodies were measured using micro vickers hardness and four probe method, respectively. The relative density of Cu/TiB_2 composite material sintered at 800°C showed about 98% of theoretical density. The Cu-1vol%TiB_2 composite material has a hardness of about 130Hv and an electric conductivity of about 85% IACS. The hardness and electric conductivity of Cu-3vol%TiB_2 composite material were about 140 Hv and about 45% IACS, respectively.
- Synthesis of Zirconium-Based Nanopowder by the Plasma Arc Discharge Process
-
Gil-Geun Lee, Kyong-Ju Kim, Je-Shin Park
-
J Korean Powder Metall Inst. 2007;14(1):63-69.
-
DOI: https://doi.org/10.4150/KPMI.2007.14.1.063
-
-
Abstract
PDF
- The present study was focused on the synthesis of a zirconium-based alloyed nanopowder by the plasma arc discharge process. The chemical composition, phase structure, particle size and hydrogen sorption property of the synthesized powders under various synthesis conditions were analyzed using XRF, XRD, SEM, XPS and the ASTM-F798 method. The chemical composition of the synthesized Zr-V-Fe-based powders approached that of the raw material with an increasing hydrogen fraction in the powder synthesis atmosphere. The synthesized Zr_55V_29Fe_16 powder consist of a mixed phase structure of the Zr,;ZrH_2,;FeV;and;Zr(V_1-xFe_x)_2 phases. This powder has an average particle size of about 20 nm. The synthesized Zr_55V_29Fe_16 nanopowder showed getter characteristics, even though it had a lower hydrogen sorption speed than the Zr_57;V36;Fe_7 getter powder. However, the synthesized Zr nanopowder with an average particle size of 20 nm showed higher hydrogen sorption speed than the Zr_57;V36;Fe_7 getter powder.
|
kpmi
