간행물

한국분말야금학회지 KCI 등재 Journal of Korean Powder Metallurgy Institute

권호리스트/논문검색
이 간행물 논문 검색

권호

Vol. 11 No. 6 (2004년 12월) 14

1.
2004.12 구독 인증기관 무료, 개인회원 유료
나노분말 기술은 나노기술이 성숙단계에 접어들 것으로 예상되는 2012년 내지 2015년경에 성숙될 기술이 아니라 이미 산업화가 빠른 속도로 이루어지고 있으며 나노기술의 산업화를 선도할 기술이다. 나노분말 기술은 에너지/환경은 물론 IT, BT 산업 등 거의 모든 신산업 분야에 활용되고 있거나 활용될 전망이다. 이러한 이유로 거의 모든 국가들이 수행하고 있는 나노기술개발 프로그램에 나노소재 기술이 중요한 분야로 다루어지고 있고 나노분말 소재기술 분야는 빠
4,000원
2.
2004.12 구독 인증기관 무료, 개인회원 유료
Dry sliding wear behavior of electro-pressure sintered Co-Fe and Co-Ni compacts was investigated. Pin-on-disk wear tests were performed on the sintered Co-Fe, Co-Ni disks against alumina balls at various loads ranging from 3N to 12N. A constant sliding speed of 0.1m/sec was employed. Wear rate was calculated by dividing the weight loss of a specimen by the measured specific gravity and sliding dis-tance. Worn surfaces and cross-sections of the specimens were examined using an SEM and EDS to investigate wear mechanism of the compacts. The wear behavior of the compacts were discussed as a function of their com-position. Effects of mechancial properties of the compact as well as oxide layers formed on wearing surface on the wear were also discussed
4,200원
3.
2004.12 구독 인증기관 무료, 개인회원 유료
The bi-materials composed of and its composite reinforced with SiC particles were prepared by ball-milling and subsequent sintering process. The size of powder in Al-Mg/SiCp mixture decreased with increasing ball-milling time, it was saturated above 30 h when the ball and powder was in the ratio of 30 to 1. Both powders mixture and mixture were compacted under a pressure of 350MPa and were bonded by sintering at temperatures ranging from 873K to 1173K for 1-5h. At 873k, the sound bi-mate-rials could not be obtained. In contrast, the bi-materials with the macroscopically well-bonded interface were obtained at higher temperatures than 873K. The length of well-bonded interface became longer with increasing temperature and time, indicating the improved contact in the interface between unreinforced Al-Mg part and Al-Mg/SiCp composite part. The relative density in the bi-materials increased as the sintering temperature and time increased, and the bi-materials sintered at 1173K for 5h showed the highest density.
4,000원
4.
2004.12 구독 인증기관 무료, 개인회원 유료
In order to fabricate a high density sintered body of ITO, nano-sized ITO powders were synthesized by coprecipitation methods. Aqueous solutions of indium and tin salts were mixed and coprecipitated by changing their pH. Coprecipitated ITO powders possessed 20-30 nm crystallite size and a relatively high BET value however, aggregation of particles were occurred. Therefore, a novel recrystallization technique was applied in order to eliminate the aggregates. The recrystallized ITO material consists of a little bit larger needlelike crystals, , and it possesses a higher BET value compared to the plain coprecipitated material . Metastable phase formation and higher content of aggregated particles were observed in the coprecipitated materials. Densification was complete after 5 hour sintering at for the recrystallized powders while densities of the coprecipitated powders were below
4,000원
5.
2004.12 구독 인증기관 무료, 개인회원 유료
The Fe-Ni compact bodies were fabricated using Fe-Ni mixed powders with 50 nm in diameter by injection molding process. The relationship between microstructure and material properties was characterized with respect to the volume ratio of powder/binder and sintering temperature with SEM and TEM. In the compact body having the volume percent ratio of 45(Fe-Ni) : 55(binder), which was sintered at the values of relative density and hardness were low about and 277.1 Hv, respectively. Using the composition of 50(Fe Ni) : 50(binder) and sintered at the values of relative density and hardness were respec-tively. The grain size of sintered bodies strongly depended on the sintering temperature. In both samples sintered at the average grain sizes were about 150 nm and 500 nm in diameter, respectively.
4,000원
6.
2004.12 구독 인증기관 무료, 개인회원 유료
Monodispersed flaky silver powder was obtained by controlling the ratios of and Agin in a mixed solution of ethylene glycol and ammonia with an addition of PVP. The effects of on its morphology and size were investigated. In molar ratio was found to be an important reaction factor for the nucleation and crystal growth of Ag powder. The synthesis of flaky powder was optimized at over 6 of molar ratio increased, the size of precipitates was increased regardless of the amount of Pt. In the absence of , the morphology and size of reduced Ag powder were found to be irregular in shape in diameter. However, homogenized fine Ag powder was obtained due to heterogeneous nucleation when used as a cat-alyst, and flaky one was synthesized with the addition of Pt over of Pt/Ag.
4,000원
7.
2004.12 구독 인증기관 무료, 개인회원 유료
We report the crystallization and magnetic properties of non-equilibrium alloy powders produced by rod-milling as well as by new chemical leaching. X-ray diffractometry, transmission electron microscopy, differential scanning calorimetry and vibrating sample magnetometry were used to characterize the as-milled and leached specimens. After 400 h or 500 h milling, only the broad peaks of nano bcc crystalline phases were detected in the XRD patterns. The crystallite size, the peak and the crystallization temperatures increased with increasing Fe. After being annealed at for 1 h for as-milled alloy powders, the peaks of bcc are observed. After being annealed at for 1 h for leached specimens, these non-equi-librium phases transformed into fcc Cu and phases for the x=0.25 specimen, and into bcc phases for both the x=0.50 and the x=0.75 specimens. The saturation magnetization decreased with increasing milling time for alloy powders. On cooling the leached specimens from ,\;the magnetization first sharply increase at about for x=0.25, x=0.50, and x=0.75 specimens, repectively.
4,000원
8.
2004.12 구독 인증기관 무료, 개인회원 유료
In this study, nano-sized indium oxide powder with the average particle size below 100 nm is fab-ricated from the indium chloride solution by the spray pyrolysis process. The effects of the reaction temperature, the concentration of raw material solution and the inlet speed of solution on the properties of powder were studied. As the reaction temperature increased from 850 to , the average particle size of produced powder increased from 30 to 100 nm, and microstructure became more solid, the particle size distribution was more irregular, the intensity of a XRD peak increased and specific surface area decreased. As the indium concentration of the raw material solution increased from 40 to 350 g/l, the average particle size of the powder gradually increased from 20 to 60 nm, yet the particle size distribution appeared more irregular, the intensity of a XRD peak increased and spe-cific surface area decreased. As the inlet speed of solution increased from 2 to 5 cc/min., the average particle size of the powder decreased and the particle size distribution became more homogeneous. In case of the inlet speed of 10 cc/min, the average particle size was larger and the particle size distribution was much irregular compared with the inlet speed of 5 cc/min. As the inlet speed of solution was 50 cc/min, the average particle size was smaller and microstructure of the powder was less solid compared with the inlet speed of 10 cc/min. The intensity of a XRD peak and the variation of specific area of the powder had the same tendency with the variation of the average par-ticle size.
4,000원
9.
2004.12 구독 인증기관 무료, 개인회원 유료
Dispersion stabilities and photocatalytic activities of rutile powders with unique nano-structure synthesized by homogeneous precipitation process at low temperature(HPPLT) have been investigated in the acrylic resin containing fluorostyrene in the range of mole. Isoelectric point of in the acrylic resin placed in the neutral region whereas that of in the water placed in the acidic region, indicating that zeta potential and agglomeration of powder is strongly dependent on the pH and the type of solvent. To prepare an adhesion, an acrylic resin containing fluorostyrene was synthesized by a radical polymerization. The adhesion of coating layer was increased with increasing fluorostyrene's contents without changing the dispersion stabilities and degrading photocatalytic properties
4,000원
10.
2004.12 구독 인증기관 무료, 개인회원 유료
Iron-carbon nanocapsules were synthesized by plasma arc discharge (PAD) process under various atmosphere of methane, argon and hydrogen gas. Characterization and surface properties were investigated by means of HRTEM, XRD, XPS and Mossbauer spectroscopy. Fe nanocapsules synthesized were composed of three phases with core/shell structures. The surface of nanocapsules was covered by the shell of graphite phase in the thickness of nm.
4,000원
11.
2004.12 구독 인증기관 무료, 개인회원 유료
Fe(C) nanocapsules were prepared by the chemical vapor condensation(CVC) process using the pyrolysis of iron Their characterizations were studied by means of X-ray diffraction, X-ray photoelectron spectrometer and transmission electron microscopy. The long-chained Fe(C) nanocapsules hav-ing the mean size of under 70 nm could be obtained below in different gas flow rates. The particle size of the powders was increased with increasing decomposition temperature, but it was decreased with increasing CO gas flow rate. The Fe powders produced at consisted of three layers of phases, but it had two phase core-shell structure which consited of phase of core and graphite of shell at
4,000원
12.
2004.12 구독 인증기관 무료, 개인회원 유료
Nano sized FeAl intermetallic particles were successfully synthesized by plasma arc discharge pro-cess. The synthesized powders shouted core-shell structures with the particle size of 10-20 nm. The core was metallic FeAl and shell was composed of amorphous Because of the difference of Fe and Al vapor pressure during synthesis, the Al contents in the nanoparticles depended on the Al contents of master alloy.
4,000원
13.
2004.12 구독 인증기관 무료, 개인회원 유료
Using the nano Fe powders having 50 nm in diameter, Fe compact bodies were fabricated by injec-tion molding process. The relationship between microstructure and material properties depending on the volume ratio of powder/binder and sintering temperature were characterized by SEM, TEM techniques. In the compact body with the volume percentage ratio of 45(Fe powder) : 55(binder), which was sintered at the relative density was about and the values of volume shrinkage and hardness were about and 242.0 Hv, respec-tively. Using the composition of 50(Fe powder) : 50(binder) and sintered at the values of relative density, volume shrinkage and hardness of Fe sintered bodies were and 152.8 Hv, respectively. They showed brittle fracture mode due to the porous and fine microstructure.
4,000원