간행물
한국분말야금학회 학술대회논문집
- 발행기관 한국분말재료학회(구 한국분말야금학회)
- 자료유형 학술대회
- 간기 부정기
- 수록기간 1993 ~ 2006
- 주제분류 공학 > 금속공학 공학 분류의 다른 간행물
- 십진분류KDC 559DDC 629
권호리스트/논문검색
한국분말야금학회 2006년도 추계학술대회논문집 (2006년 9월) 358건
261.
2006.09
구독 인증기관·개인회원 무료
TZM alloy having elongated coarse-grain structure was developed by three-step internal nitriding treatment at 1423 to 1873 K in and subsequent recrystallization treatment at 2173 K in vacuum. Some specimens were subjected to re-nitriding treatment at 1873 K for 16 h. After the recrystallization treatment, aspect ratio (L/W) of grains for rolling direction was about 50 at the maximum. Yield stress obtained at 1773 K after re-nitriding treatment was about 6 times as large as that of recrystallized specimen. Re-nitriding was very effective in the improvement in strength of TZM alloy having elongated coarse-grain structure.
262.
2006.09
구독 인증기관·개인회원 무료
An experiment was carried out to investigate the effect of Ba Stearate as a reducing agent on the magnetic and physical properties of anisotropic type ferrite magnets. It was found that the magnetic properties of were improved by adding 0.3 wt% of Ba Stearate, 0.5 wt% of , and 0.5 wt% of CaO together. The optimum conditions for making magnets were as follows; semisintering condition: h in nitrogen gas atmosphere, drying condition: h in air, sintering condition: h in nitrogen gas atmosphere. Magnetic and physical properties of a typical sample were = 0.46 T, = 0.43 T, = 182.3 kA/m, = 177.2 kA/m, = 33.8 kJ/, = and = and = 1332 kA/m.
263.
2006.09
구독 인증기관·개인회원 무료
In this study, the pure iron powder was treated with aqueous phosphoric acid to produce phosphate insulating layer on the surface. After drying the powder, it was compacted in a mold with a diameter of 20mm at 800MPa. The powder compacts were then heat treated at for 1 hour. The results showed that insulated iron powder was obtained with uniform phosphate layer by chemical reaction. With increased amount of phosphate layer, the core loss and density of compacts were decreased. It was also found that the addition of ethyl alcohol during insulating reaction resulted in improved core loss value.
264.
2006.09
구독 인증기관·개인회원 무료
We made a high-speed motor and a DC brush-less motor for factory automation (FA) to investigate applicability of powder magnetic core to motor application, and compared those performances with the similar motors having conventional electro magnetic steel core. Permeability and saturated magnetization of powder magnetic core are less than those of elect romagnetic steel core, however output performances of each core motor are almost the same. The FA motor with powder magnetic core using three-dimensional magnetic circuit showed higher torque than the same volume motor with electromag netic steel core.
265.
2006.09
구독 인증기관·개인회원 무료
Addition of 2.0wt% or 0.3wt%Sn proved to be very effective in improving the permanent magnetic properties of NdFeNbB magnets. additions result in the increase in the Hci and temperature dependence due to formation of (NdDy)-rich phase and grain refinement of phase. This improvement of the coercivity stability of the magnets from the addition of Sn is attributed to the smoothing effect of the Sn addition at the grain boundaries. The magnetic properties, the temperature dependence and Curie temperature of NdFeNbB with and Sn combined addition were found to be considerably improved
266.
2006.09
구독 인증기관·개인회원 무료
Improvement of the strength is one of the most important subjects on soft magnetic composite (SMC) to increase the applica ble items. In this study, lubricants for inner lubricating SMC, which can be produced in lower cost than die wall-lubricatin g SMC, varied to investigate their effect on the strength. The newly developed SMC with self-lubricating resin shows high st rength equivalent to that of SMC obtained by die wall lubrication.
267.
2006.09
구독 인증기관·개인회원 무료
Influences of machining on magnetic properties of soft magnetic composites (SMC's) with addition of two kinds of binder, i.e., organic binder and inorganic one, were investigated. Machining does not affect DC magnetic properties of the SMC compacts. This can be ascribed to their particular structure in which the ironpowder particles are highly isolated by the binder. On the other hand, decrease in resistivity and resultant increase in eddy current loss was confirmed in the machined compacts containing inorganic binder. It is supposed that the brittleadditive binder existing between the iron particles is partly broken, and iron-to-iron contact is formed on the machined surface.
268.
2006.09
구독 인증기관·개인회원 무료
Magnetic Properties of dust cores made of mixtures of atomized pure iron powder and pure alumina powder has been investigated in the temperature range from 673 to 1073K. The effect of annealing on coercivity has been positive effect up to 973K and thus coercivity is gradually reduced form 280A/m (as-compressed) to 160A/m (973K). However, dust cores annealed at 1073K displayed a 15% increasing of coercivity by annealing at 973K. Hysteresis loss shows a tendency similar to coercivity. Microstructure observation of specimens shows grain refinement by recrystallization in the temperature range from 773 to 1073K.
269.
2006.09
구독 인증기관·개인회원 무료
Y-type barium ferrite ( Me=Zn, Co, Cu) expected as an electromagnetic wave absorber were prepared by the glass-ceramic method. The glasses with composition of were prepared. Single-phase powders of Y type barium ferrite were obtained with the composition . The shape of Y-type crystals depended strongly on the heating temperature and changed from a plate-like hexagon to a complex polyhedron with increasing heating temperature. Correlation was recognized between saturation magnetization and crystal shape. Electromagnetic wave absorption characteristics was affected by the saturation magnetization and crystal shape.
270.
2006.09
구독 인증기관·개인회원 무료
Y-type barium ferrite was prepared by the glass-ceramic method. Glasses with composition of were prepared, and the precipitation behavior of Y-type ferrite from the glass matrix was investigated by heating glass specimens at various temperature. which is a precursor of M-type ferrite was precipitated at about 813 K and an unknown compound, phase X, was precipitated at about 850 K. M-type ferrite and Y-type ferrite started to form at about 923 K and 1103 K, respectively. The formation of Y-type ferrite was int erpreted as the result of the reaction of M-type ferrite with a melt of phase X.
271.
2006.09
구독 인증기관·개인회원 무료
Core loss of soft magnetic powder cores have been focused on to achieve high efficiency of power supplies. In this study the effects of crystal grain size on core loss were investigated by changing heat treatment conditions. It was found that core loss is influenced by crystal grain size because eddy current loss decreased and hysteresis loss increased by making crystal grain size smaller, and it is also influenced by particle size.
272.
2006.09
구독 인증기관·개인회원 무료
In order to obtain specific magnetic properties, it is of paramount importance to increase the alloy density of components fabricated by powder metallurgy. An alternative to increase the density of alloys such as Fe-49Co-2V would be the use of elemental Fe and Co instead of the pre-alloyed powder. Trying to give some insight on the industrial application of this strategy, this paper investigates the replacement of more conventional pre-alloyed Fe-49Co-2V powders with elemental Fe and Co. A previous analysis shows that it is possible to achieve higher densities and leads to a noticeable improvement in some important magnetic properties.
273.
2006.09
구독 인증기관·개인회원 무료
Boareto, J.C., Soyama, J., Felisberto, M.D.V., Hesse, R., Pinto, A.V.A., Taylor, T.R., Wendhausen, P.A.P.
This paper compares the effect of using different types of iron powders for the preparation of by calciothermic reduction-diffusion (CRD). Three types of iron powder were used: carbonyl, sponge and water atomized. The results show that, when immediately nitrogenated after the CRD process, prepared from sponge and water atomized iron powders yield -magnets with a high degree of texture. However, after a suitable treatment with hydrogen followed by nitrogenation, -powders made from Carbonyl iron produce magnets with the best quality regarding coercivity, remanence and degree of texture.
274.
2006.09
구독 인증기관·개인회원 무료
275.
2006.09
구독 인증기관·개인회원 무료
276.
2006.09
구독 인증기관·개인회원 무료
277.
2006.09
구독 인증기관·개인회원 무료
Eventhough Fe-6.5 wt.% Si alloy shows excellent magnetic properties, magnetic components made of the alloy are not totally because of its extremely low ductility. In order to overcome this demerit of alloy, 6.7 wt.% Si alloy powders were produced by gas atomization and then post-processed to form magnetic cores. By doing so, the total core loss could be minimized by reducing both hysteresis and eddy current loss. From our experiments, we were able to achive a core loss of at 0.1 T and 50 kHz through proper processes and a permeability of 68 at low frequency.
278.
2006.09
구독 인증기관·개인회원 무료
The magnetic ferrite nanoparticles were synthesized and coated by silica precursor in controlling the coating thicknesses and sizeses. The surface modification was performed with amino-functionalized organic silanes on silica coated magnetic nanoparticles. The use of functionalized self-assembled magnetic ferrite nanoparticles for nucleic acid separation process give a lot of advantages rather than the conventional silica based process.
279.
2006.09
구독 인증기관·개인회원 무료
280.
2006.09
구독 인증기관·개인회원 무료
FePt binary-alloy nanopowder has been successfully synthesized by chemical vapor condensation process with two metal organic precursors, i.e., iron pentacarbonyl and platinum acetylacetonate. Average particle size of the powder was less than 50 nm with very narrow size distribution, revealing high dispersion capability. Characteristics of the powder could be controlled by changing process parameters such as reaction temperature, chamber pressure, as well as gas flow rate. Magnetic properties of the synthesized FePt nanopowder were investigated and analyzed in terms of the powder characteristics.
