간행물
한국분말야금학회지 KCI 등재 Journal of Korean Powder Metallurgy Institute
- 발행기관 한국분말재료학회(구 한국분말야금학회)
- 자료유형 학술지
- 간기 격월간
- ISSN 1225-7591 (Print)2287-8173 (Online)
- 수록기간 1994 ~ 2024
- 주제분류 공학 > 금속공학 공학 분류의 다른 간행물
- 십진분류KDC 559DDC 629
권호리스트/논문검색
Vol. 14 No. 1 (2007년 2월) 11건
1.
2007.02
구독 인증기관 무료, 개인회원 유료
4,000원
2.
2007.02
구독 인증기관 무료, 개인회원 유료
The effect of a CAM (Continuous Attrition Mill) treatment on the sinterability of ex-ADU powder was investigated. As the cycles of a CAM increased, the apparent density, specific surface area and O/U of the milled powder increased, but there particle sizes decreased. However the sintered density of the pellet decreased as the cycles of the CAM increased. It is considered that the decrease of the sintered density is due to the formation of , which was produced by a CAM mechanism
4,000원
3.
2007.02
구독 인증기관 무료, 개인회원 유료
The mother Ni-W (1-5 wt.%) alloy billets for coated conductor substrate were fabricated by powder metallurgy process. The tensile test results for the sintered Ni-W rods showed the increase of mechanical strength and decrease of ductility with increasing W content due to the solid solution hardening. All the fracture surfaces of the tested specimens showed the typical ductile fracture mode of dimple rupture due to the local necking. The Ni-W alloy billets were made into tape by cold rolling. After the appropriate heat treatment for recrystallization, the brass texture formed by the cold rolling was converted to the complete cube texture. The in-plane and out of plane texture of the tapes estimated by x-ray pole figure were smaller than 9 degree and 7 degree, respectively. The effect of the W addition on the texture development seems not to be significant.
4,000원
4.
2007.02
구독 인증기관 무료, 개인회원 유료
This study was focused on the optimization of low-pressure ultrasonic spraying process for synthesis of pure nanoparticles. As process variables, pressure in the reactor, precursor concentration, and reaction temperature were changed in order to control the chemical and microstructural properties of iron oxide nanoparticles including crystal phase, mean particle size and particle size distribution. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies revealed that pure nanoparticles with narrow particle size distribution of 5-15 nm were successfully synthesized from iron pentacarbonyl () in hexane under 30 mbar with precursor concentrations of 0.1M and 0.2M, at temperatures over . Also magnetic properties, coercivity () and saturation magnetization () were reported in terms of the microstructure of particles based on the results from vibration sampling magnetometer (VSM).
4,000원
5.
2007.02
구독 인증기관 무료, 개인회원 유료
Manufacturing bulk nanostructured materials with least grain growth from initial powders is challenging because of the bottle neck of bottom-up methods using the conventional powder metallurgy of compaction and sintering. In this study, bottom-up type powder metallurgy processing and top-down type SPD (Severe Plastic Deformation) approaches were combined in order to achieve both real density and grain refinement of metallic powders. ECAP (Equal Channel Angular Pressing), one of the most promising processes in SPD, was used for the powder consolidation method. For understanding the ECAP process, investigating the powder density as well as internal stress, strain distribution is crucial. We investigated the consolidation and plastic deformation of the metallic powders during ECAP using the finite element simulations. Almost independent behavior of powder densification in the entry channel and shear deformation in the main deformation zone was found by the finite element method. Effects of processing parameters on densification and density distributions were investigated.
4,000원
6.
2007.02
구독 인증기관 무료, 개인회원 유료
Using spark plasma sintering process (SPS), Ti-6Al-4V alloy powders were successfully consolidated without any contamination happened due to reaction between the alloy powders and graphite mold. Variation of microstructure and mechanical properties were investigated as a function of SPS temperature and time. Compared with hot isostatic pressing (HIP), the sintering time and temperature could be lowered to be 10 min. and , respectively. At the SPS condition, UTS and elongation were about 890 MPa and 24%, respectively. Considering the density of 98.5% and elongation of 24%, further improving the tensile strength would obtain by increasing the SPS pressure.
4,000원
7.
2007.02
구독 인증기관 무료, 개인회원 유료
Cu-Zn alloy nano powders were fabricated by the electrical explosion of Zn-electroplated Cu wire along with commercial brass wire. The powders exploded from brass wire were composed mainly of phases while those from electroplated wires contained additional Zn-rich phases as , and Zn. In case of Zn-elec-troplated Cu wire, the mixing time of the two components during explosion might not be long enough to solidify as the phases of lower Zn content. This along with the high vapor pressure of Zn appears to be the reason for the observed shift of explosion products towards the high-Zn phases in electroplated wire system.
4,000원
8.
2007.02
구독 인증기관 무료, 개인회원 유료
In the fabrication of dye-sensitized solar cells (DSSCs), carbon counter electrode has been tested for replacing the platinum counter electrode which has two drawbacks: limited surface area and high material cost. Poor mechanical stability of carbon layer due to weak bonding strength to electrically conductive TCO (transparent conducting oxide) glass substrate is a crucial barrier for practical application of carbon counter electrode. In the present study a carbon counter electrode with high conversion efficiency, comparable to Pt counter electrode, could be fabricated by adaption of a bonding layer between particulate carbon material and TCO substrate.
4,000원
9.
2007.02
구독 인증기관 무료, 개인회원 유료
The hydrogen sorption speeds of amorphous alloy and its crystallized alloys were evaluated at room temperature. amorphous alloy was prepared by ball milling. The hydrogen sorption rate of the partially crystallized alloy was higher than that of amorphous. The enhanced sorption rate of partially crystallized alloy was explained in terms of grain refinement that has been known to promote the diffusion into metallic bulk of the gases. The grain refinement could be obtained by crystallization of amorphous phase resulting in the observed increase in sorption property.
4,000원
10.
2007.02
구독 인증기관 무료, 개인회원 유료
Getter property of nano-sized metallic powders was evaluated as a possible candidate for the future getter material. For the purpose, Ti powders of about 50 nm were prepared by electrical wire explosion. Commercial Ti powders of about 22 micrometer were tested as well for comparison. The room-temperature hydrogen-sorption speed of nano-sized Ti powders was which was more than 4 times higher than that of micron-sized ones. The value is comparable to or even higher than those of commercial products. Its sorption speed increases with activation temperature up to above which it deteriorates due to low-temperature sintering effect of nano-sized particles.
4,000원
11.
2007.02
구독 인증기관 무료, 개인회원 유료
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 powder consist of a mixed phase structure of the phases. This powder has an average particle size of about 20 nm. The synthesized nanopowder showed getter characteristics, even though it had a lower hydrogen sorption speed than the getter powder. However, the synthesized Zr nanopowder with an average particle size of 20 nm showed higher hydrogen sorption speed than the getter powder.
4,000원
