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. 11 No. 1 (2004년 2월) 10건
1.
2004.02
구독 인증기관 무료, 개인회원 유료
FGM은 원하는 물성의 점진적인 변화를 통해 재료에 다양한 특성을 확보할 수 있는 방법이다. 여러FGM의 제조 방법 중 분말야금법과 열용사법이 많이 사용되며, FGM적용은 열ㆍ기계적 물성이 요구되는 응용분야에서 가장 전망이 있고 현재 가장 많은 연구가 진행되어 왔다. 경사기능의 도입은 2층 구조의 재료에 비하여 열팽창 계수의 차이에 의한 층간 잔류응력 집중을 완화 시켜 접합 강도와 열 충격 특성 및 열피로 특성 등의 향상을 가져왔다. 그러나 120 이상
4,000원
2.
2004.02
구독 인증기관 무료, 개인회원 유료
The nano-sized Co particles were successfully synthesized by chemical vapor condensation (CVC) process using the precursor of cobalt carbonyl (). The influence of carrier gases on the microstructure and magnetic properties of nanoparticles was investigated by means of XRD, TEM, XPS and VSM. The Co nano-particles with different phases and shapes were synthesized with a change of carrier gas : long string morphologies with coexistence of fcc and hcp structure in Ar carrier gas condition; finer Co core in a mass of cobalt oxide with only fcc structure in He; rod type cobalt oxide phase in Ar＋6vol％. The saturation magnetization and coercivity was lower in Co nanoparticles synthesized in He carrier gas, due to their finer size.
4,000원
3.
2004.02
구독 인증기관 무료, 개인회원 유료
The Indium Tin Oxide(ITO) nano powders were prepared by spray drying and heat treatment process. The liquid solution dissolved Indium and Tin salts was first spray dried to prepare chemically homogeneous recursor powders at the optimum spray drying conditions. Subsequently, the precursor powders were subjected to eat treatment process. The nano size ITO powders was synthesized from the previous precursor powders and the npuities also were decreased with increasing heat treatment temperature. Furthermore, the lattice parameter of TO nano powders was increased by doping Tin into Indium with increasing heat treatment temperature. The par icle size of the resultant ITO powders was about 20∼50nm and chemical composition was composed of In:Sn =86:10 wt.％ at 80.
4,000원
4.
2004.02
구독 인증기관 무료, 개인회원 유료
In the present study, the focus is on the analysis of carbothermal reduction of the titanium-cobalt-oxygen based oxide powder by solid carbon for the optimizing synthesis process of ultra fined TiC/Co composite powder. The titanium-cobalt-oxygen based oxide powder was prepared by the combination of the spray drying and desalting processes using the titanium dioxide powder and cobalt nitrate as the raw materials. The titanium-cobalt-oxygen based oxide powder was mixed with carbon black, and then this mixture was carbothermally reduced under a flowing argon atmosphere. The changes in the phase structure and thermal gravity of the mixture during carbothermal reduction were analysed using XRD and TGA. The synthesized titanium-cobalt-oxygen based oxide powder has a mixture of and . This oxide powder was transformed to a mixed state of titanium car-bide and cobalt by solid carbon through four steps of carbothermal reduction steps with increasing temperature; reduction of to and Co, reduction of , to the magneli phase(, n>3), reduction of the mag-neli phase(, n>3) to the (2n3) phases, and reduction and carburization of the (2n3) phases to titanium carbide.
4,000원
5.
2004.02
구독 인증기관 무료, 개인회원 유료
The effect of extrusion temperature on the microstructure and mechanical properties were studied in He-gas atomized alloy powders and their extruded bars using SEM, tensile testing and thermal expansion testing. The extruded bar of alloy consists of a mixed structure in which fine Si particles with a particle size below 20∼500nm and very fine compounds with a particle size below 200nm are homogeneously dispersed in Al martix with a grain size below 500nm. With increasing extrusion temperature, the microstructural scale was decreased. The ultimate tensile strength of the alloy bars has incresed with decreasing extrusion temperature from 500 to 35 and alloy extreded at 35 shows a highest tensile strength of 810 MPa due to the fine namostructure. The addition of Ni and Ce decreased the coefficients of thermal expansion and the effects of extression temperature on the thermal expansion were not significant.
4,000원
6.
2004.02
구독 인증기관 무료, 개인회원 유료
The electrical and thermal conductivity of W-Cu composites were investigated as a function of the W-particle size and W-W contiguity. Powder mixtures were prepared by ball milling or mechanical alloying process, and then sintered at various temperatures. The electrical conductivity of sintered composite was increased with decreasing W grain size. Dependence of electrical conductivity on the W grain size was explained by the W-W contiguity concept. The thermal conductivity was increased with increasing the temperature up to but decreased at the temperature above Also, thermal conductivity value was influenced by the W particle size. Change of thermal conductivity in W-Cu composites was discussed based on the observed microstructural characteristics and theoretical considerations.
4,000원
7.
2004.02
구독 인증기관 무료, 개인회원 유료
Nanoparticles of iron oxides have been prepared by the levitational gas condensation (LGC) method, and their structural and magnetic properties were studied by XRD, TEM and Mossbauer spectroscopy. Fe clusters were evaporated from a surface of the levitated liquid Fe droplet and then condensed into nanoparticles of iron oxide with particle size of 14 to 30 nm in a chamber filled with mixtures of Ar and gases. It was found that the phase transition from both - and -Fe to , which was evaluated from the results of Mossbauer spectra, strongly depended on the flow rate. As a result, - was synthesized under the flow rate of 0.1(Vmin)0.15, whereas was synthesized under the , flow rate of 0.15(Vmin)0.2.
4,000원
8.
2004.02
구독 인증기관 무료, 개인회원 유료
TiNi bodies were produced from (Ti＋Ni) powder mixture by spark-plasma sintering procerg. The sintering behavior was investigated through the measurement of change in density, densification rate, phase analysis and microstructure. Irrespective of heating rate, sintered bodies with above 97％ relative density could be obtained. TiNi with B2 structure was confirmed as the major phase and , unreacted Ti, Ni as the second phase. Increase in heating rate suppressed a formation of intermediate phase during sintering process. Increase in holding time at sintering temperature led to a compositional homogenization.
4,000원
9.
2004.02
구독 인증기관 무료, 개인회원 유료
Pulsed wire evaporation (PWE) method is known as the promising production-technique for nanopowders. In this study, we developed and modified the previous single wire explosion equipment to the simultaneous two-wire explosion one for the fabrication of alloy or mixture of nano metallic powder. First of all, both the theoretical and empirical background of pulsed wire explosion of single wire were summarized, and compared with our experimental results for Cu and Al single wlre explosion. After then, the simultaneous wire evaporation equipment was designed, constructed, and tested. The current and voltage behavior were well matched between the calculated ones from the circuit equations, and the experimental results from simultaneous explosion of Cu and Al wire.
4,000원
10.
2004.02
구독 인증기관·개인회원 무료
The sintering characteristics of commercial 7xxx series Al-Zn-Mg-Cu alloy have been investigated. Sintering system of this blended elemental powder has aspects of both transient and supersolidus liquid phase sintering. Transient liquids occur when the constitution point during sintering lies in a solid phase region but where the sintering temperature is greater than either the melting point of one of the constituent or a eutectic temperature. Supersolidus liquid phase sintering occurs when a preblended powder is heated to a temperature between the solidus and liquids. However, these reaction were restrained their inter diffusion due to the appearance of the oxide film. Thus, 7xxx series Al alloy is extremely sensitive to process variables, including particle size, holding time and sintering temperature. Therefore, above phenomenons were observed formation and behaviour of the liquid by using SEM and DSC.
