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61 巻, 12 号
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浅井 滋生1997 年 61 巻 12 号 p. 1271
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーPDF形式でダウンロード (148K) -
若山 信子1997 年 61 巻 12 号 p. 1272-1277
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーMagnetohydrodynamic effects have been widely used in the area of electromagnetic processing of materials. However, there have been few studies about the phenomena caused by another kind of magnetic force: F=1⁄2χ·grad∫H2 dV (χ: volume magnetic susceptibility, H: magnetic strength). This review introduces the new kind of magnetic effects. Recently, magnetic attractive force acting on paramagnetic oxygen gas has been found to induce gas flows and combustion. This new research area “magnetoaerodynamics” is important to control air flows and combustion (II∼IV). In space shuttle, bubbles cause many troublesome problems. The magnetic buoyancy force acting on a bubble was used to transport bubbles in liquid under microgravity environments (V). The magnetic force acting on a protein supersaturated solution upward was found to produce virtual low gravity in it and decrease the number of crystals (VI). Furthermore, magnetic orientation of protein crystals was used to study the initial process of crystallization of protein crystals, the mechanism of which has not been clarified (VII). Recently, helium free superconductive magnets have been developed, and it is easy for a scientist to use strong magnetic fields. Thus, strong magnetic field, specially the virtual gravity, will provide a new environment to synthesize new materials.抄録全体を表示PDF形式でダウンロード (1137K) -
茂木 巖, 大久保 晋, 神子 公男1997 年 61 巻 12 号 p. 1278-1282
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーThe magnetic field effects were investigated on the dendritic growth morphology in electrodeposition, electroless deposition and electropolymerization. The magnetohydrodynamic effect inducing convections in the solutions leads to spiral and compact growth patterns of the zinc electrodeposits. The Lorentz force acting on the elementary motions in the diffusion of ions leads to dense-branching morphology of silver electroless deposits with a smooth growth front. Dense-film growth of magneto-electropolymerized polypyrrole was considered to result from the effect of diamagnetic orientation. The magneto-electropolymerization was applied to the control of the electrochemical properties of the polypyrrole films.抄録全体を表示PDF形式でダウンロード (437K) -
佐々 健介, 森川 拓, 浅井 滋生1997 年 61 巻 12 号 p. 1283-1287
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーIn this paper, we found that the application of a magnetic field makes primary dendrite arms of MnBi formed in a molten Bi-4 mass%Mn alloy align parallel to the magnetic field and makes the plate of an Al-9 mass%Si-15 mass%Fe intermetallic compound crystallized in a molten Al-11 mass%Si-2 mass%Fe alloy align perpendicular to the magnetic field. Moreover, we found that the magnetic field aligns graphite particles so as to be perpendicular to the a- and b-planes and parallel to the c-plane. These experimental results can be explained by considering well-known magnetic energies due to shape magnetic anisotropy and crystal magnetic anisotropy.抄録全体を表示PDF形式でダウンロード (549K) -
安田 秀幸, 大中 逸雄, 古久保 洋二, 福田 承生, 渡辺 和雄, 高 漢俊1997 年 61 巻 12 号 p. 1288-1295
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーA thermoelectric material(Bi0.25Sb0.75)2Te3 was grown by a vertical gradient freezing technique in high magnetic fields of up to 8 T. The radial distribution of composition showed macrosegregation when the specimens were solidified in the magnetic field. The radial segregation increased with increasing intensity of the magnetic field. On the other hand, the longitudinal distribution for both the specimens under 0 T and 8 T had a variation at the initial transient, but no effect of the magnetic field on the composition distribution was observed. A numerical calculation of the solid/liquid interface shape, thermal and solutal fields suggested that the difference in thermal conductivity between the solid and the liquid phases would cause the concave interface shape and a driving force of the convection around the s⁄l interface. It was concluded that the interaction of the convection mass transfer reduced by the magnetic field interacts with the diffusion mass transfer, causing the radial macrosegregation.抄録全体を表示PDF形式でダウンロード (1396K) -
山本 勲, 山口 益弘, 出口 典孝, 三浦 成人1997 年 61 巻 12 号 p. 1296-1299
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーMagnetic field effects on the chemical equilibrium were investigated for a ferromagnetic metal hydride-hydrogen system. The equilibrium hydrogen pressure, measured in the β+γ region for LaCo5Hx, changed significantly with the applied magnetic fields up to 15 T in the temperature range between 293 and 343 K. Namely, the measured hydrogen pressure increased with increasing magnetic fields. However, such a change in the equilibrium pressure became less remarkable with increasing temperature. These experimental results agreed with the thermodynamic calculation based on magnetic data.抄録全体を表示PDF形式でダウンロード (548K) -
宮本 淳一, 松原 良子, 倉嶋 太, 田崎 貴之, 尾関 寿美男1997 年 61 巻 12 号 p. 1300-1305
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーThe magnetic field effects on gas-solid interactions were examined, using physical adsorption systems of methanol, t-butanol, benzene and O2 onto carbon black (NPC), activated carbon fiber (A10) and zeolite 5 A (Z5A). With some previous results on the magnetic-field-induced adsorption and desorption of H2O and NO, a possibility of the magnetic control of gas/solid adsorption equilibrium was discussed. When a homogeneous steady magnetic field was applied to such gas/solid adsorption systems under equilibrium, amount of adsorption changes, being referred to magnetoadsorption (MA) and magnetodesorption (MD). The dependence of MAD on magnetic field intensity was classified into four types, depending on the kind of solids and adsorptives: MD (I), MA (II), MD-to-MA transition (III), and MA-to-MD transition (IV). Benzene/NPC, O2/A10 and O2/Z5A systems were type II and a methanol/NPC system was type IV (which was first observed). To understand thermodynamically MAD, we must presume certain magnetic states in adsorbed phases different from its bulk phase, which should arise from interaction between an adsorptive and a solid and/or between adsorptives during the adsorption process. Thus, it is possible that adsorption equilibrium is controlled by an external magnetic field, designing magnetic interactions in the adsorption process.抄録全体を表示PDF形式でダウンロード (700K) -
Baskin Donald M., Faber Katherine T., 大塚 秀幸1997 年 61 巻 12 号 p. 1306-1310
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーSingle phase laminates of iron titanate were formed by gelcasting both in the presence and absence of a magnetic field to produce alternating layers of textured and non-textured microstructure, respectively. X-ray analysis was performed on each lamina verifying that alignment was maintained throughout processing. Toughness of trilayer laminates (non-textured/textured/non-textured) were measured using a modified version of the short double cantilever beam geometry. Toughness experiments resulted in large scale crack deflection of several hundred microns. Peak toughnesses were measured to be well over 8 MPa·m1⁄2 which is a substantial improvement over monolithic iron titanate.抄録全体を表示PDF形式でダウンロード (501K) -
Kossikhina Svetlana, 伊藤 栄子, 木村 恒久, 川原 正言1997 年 61 巻 12 号 p. 1311-1317
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーA magnetic orientation could be a novel means to control the orientation of commercial liquid crystalline (LC) copolyesters and to provide addtional physical and mechanical properties for the final product. Here we repot the thermomechanical properties of a magnetically oriented copolyester, one from Xydar series, and compare them with those obtained for the mechanically stretched film of a similar orientation degree.
The axial elastic modulus and ultimate tensile strength of the magnetically oriented films were lower than those exhibited by the uniaxially stretched sample, but these mechanical properties measured in the transverse direction were higher for the magnetically oriented film. Below the glass transition, the magnetically oriented and uniaxially stretched films showed similar values of the coefficient of thermal expansion both in the axial and transverse directions. However, at elevated temperatures, the magnetically oriented film showed lower axial and transverse expansions by the factors of 6 and 2, respectively. The less anisotropy of tensile properties and the better dimentional stability of the magnetically oriented film could be a merit of a magnetic orientation. The difference in these properties are interpreted in terms of the oriented microstructures.抄録全体を表示PDF形式でダウンロード (1150K) -
中村 浩章, 池田 一昭, 山口 作太郎1997 年 61 巻 12 号 p. 1318-1325
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーElectric generator by the Nernst effect in a strong magnetic field, which is called a Nernst element, was proposed in a few years ago. We have developed a measuring system of transport coefficients, which are the thermoelectric coefficient α and the Nernst coefficient N, to find the Nernst element which has a good figure of merit. We obtained the temperature T and the magnetic field B dependence of both α and N of InSb, which has a high mobility and which is one of candidates of the Nernst elements, when 263 K≤T≤373 K and B≤4 T. We measured two types of InSb samples, which we called sample A and sample B. Their carrier concentrations at 77 K are n=2.1×1022 m−3 and n=2.9×1021 m−3, respectively. This measurement gives the following two important results: (i) Both α and N of sample B, which is in the intrinsic region near room temperature, are higher than those of sample A. (ii) the N of both samples are proportional to B up to 4 T. This fact is inconsistent with theoretical result, that is, N∝1⁄B2.抄録全体を表示PDF形式でダウンロード (810K) -
掛下 知行, 福田 隆, 川村 良雄, 佐分利 敏雄, 金道 浩一, 西村 新, 山本 純也1997 年 61 巻 12 号 p. 1326-1332
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーEffects of external fields, such as temperature, magnetic field, stress and combaination of those fields have been examined on the onset of martensitic transformations in SUS304L, SUS304 and SUS316 austenitic stainless steels. Following results are obtained: an athermal γ→ε′→α′ martensitic transformation is not induced in all the steels, but an isothermal γ→ε′→α′ transformation takes place in SUS304L. The austenitic γ state in SUS304 and SUS316 exhibits an antiferromagnetic transition at about 40 and 30 K, respectively, and it may also exhibit an antiferromagnetic spin-flip under a magnetic field of about 3 MA/m at 4.2 K. Any magnetic field-induced martensitic transformation does not occur in the austenitic states of SUS304 and SUS316 even when the pulsed magnetic field up to 30 MA/m is applied in the wide temperature range between 4.2 and 290 K. On the other hand, in SUS304L which contains isothermally transformed ε′ and α′ martensites, the magnetic field-induced martensitic transformation from pre-existed ε′ to α′ martensites occurs at 4.2 and 77 K. All the steels easily show deformation-induced martensitic transformation. However, in all the deformed steels, magnetic field does not induce any martensitic transformation in the wide temperature range between 4.2 and 290 K. The above results, especially concerned with the effect of magnetic field on the martensitic transformation, are discussed in view of the magnetic energy previously proposed.抄録全体を表示PDF形式でダウンロード (889K) -
大塚 秀幸, Ghosh Gautam, 間宮 広明, 和田 仁1997 年 61 巻 12 号 p. 1333-1336
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーAging of an Fe-23.3Ni-9.4Al(mass%) alloy was carried out both in the presence of a magnetic field (9 T) and without a magnetic field at 673, 773, 873 and 973 K for 5 h. The saturation magnetic moment of the samples were measured at 200, 100, 50 and 5 K and extrapolated to 0 K. A systematic difference in average magnetic moment is observed between the samples aged with and without magnetic field. Except for aging at 773 K, the average magnetic moment of the samples aged under magnetic field is smaller than those aged without a magnetic field. TEM observation showed the evidence of spinodal decomposition of disordered bcc (A2) and ordered bcc (B2) phases. The difference in magnetic moments is attributed to the difference in kinetics of ordering/decomposition due to the magnetic field.抄録全体を表示PDF形式でダウンロード (530K) -
大塚 秀幸, Ghosh Gautam, 長井 寿, 和田 仁1997 年 61 巻 12 号 p. 1337-1340
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーThe dimensions of fully grown martensite plates in Fe-27Ni-0.8C(mass%) and Fe-31Ni-0.4C alloys formed at 4.2 K under applied magnetic field (10 T) and tensile stress (220 MPa) are reported. The plates formed in cluster are classified into two categories during stereological measurements: the plates whose radial growth is limited by the austenitic grain boundaries only (Type I), and the plates whose radial growth is limited by the pre-existing martensitic plates only (Type II). It is demonstrated that the formation sequence of the plates has a strong effect on the radial growth and aspect ratio. The measured aspect ratio of type I plates in the Fe-27Ni-0.8C alloy agree very well with an earlier prediction based on the aspect ratio measurements in the temperature range of 193 to 77 K in an Fe-23.2Ni-2.9Mn alloy. Both these alloys are non-invar. However, in the case of Fe-31Ni-0.4C alloy, which is expected to be invar, the measured aspect ratio is less than the predicted value at 4.2 K.抄録全体を表示PDF形式でダウンロード (403K) -
金 炳男, 岸 輝雄1997 年 61 巻 12 号 p. 1341-1346
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーTwo-dimensional simulation of grain growth behavior of polycrystallne aggregates is conducted on the base of the concept proposed by the atomic jump model. The decrease of grain boundary surface energy due to the reduction of surface area becomes the driving force for the boundary migration. The moving velocity of the grain boundary is determined by the thermally activated jump of atoms. The simulation is carried out with a unit of triple point which is constructed with three straight boundaries. The direction and the velocity of the triple points are determined by using the atomic jump model. As a result, it is found that the average area of grain is linearly proportional to the time, and that the grain size distribution can be represented by the Louat function.抄録全体を表示PDF形式でダウンロード (567K) -
金 炳男, 岸 輝雄1997 年 61 巻 12 号 p. 1347-1351
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリー2-dimensional simulation of the migration behavior of grain boundary for regular polygons is carried out by using the finite element method. In the finite element calculation, a straight line element is applied to represent the grain boundaries where surface tension exerts. The driving force for boundary migration is the free energy reduction per unit volume atoms crossing the boundary. The polygons with edges less than 6 shrinks and finally disappears, while those with edges more than 6 grows. The grain boundary shape between triple points at steady state can be approximated by circle arcs. The migration velocity of the grain boundary is inversely proportional to the grain radius, indicating that a square of the radius is proportional to the time. The proportional constant increases with the number of edges of the regular polygons. In the case of a regular trigonal grain, the predicted annihilation time is consistent well with that from the theoretical model.抄録全体を表示PDF形式でダウンロード (478K) -
高木 真一, 大内 千秋1997 年 61 巻 12 号 p. 1352-1357
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーWe reported before that cast and HIP’ed TiAl alloys with adequate Zr-addition showed the excellent strength-ductility balance at room temperature. In this study, the tensile strength at high temperatures and the fracture toughness at room temperature of the Zr-added alloys were investigated. Ti-48 at%Al alloy was chosen as the base alloy and Zr was added up to 4 at% in the base alloy with Al/(Ti+Al) of 0.48 atomic ratio. Microstructure of Zr-added alloys consisted of higher volume fraction of the grains in lamellar form and equiaxed γ grains. Equiaxed γ region had the Zr segregated zone which enclosed the lamellar colonies forming like a network. This microstructural feature resulted in the excellent strength-ductility balance at room temperature as discussed in detail previously. In the results of tensile test at high temperatures up to 1073 K, 2 at%Zr-added alloy showed higher strength than that of the base alloy. Fracture toughness at room temperature increased with increasing Zr content. For the binary alloy and the Zr-added alloys, the tensile strength at 1073 K and the fracture toughness at room temperature showed a linear relationship with the volume fraction of the grains in lamellar form. Therefore the advantages of the lamellar structure brought about the higher tensile strength at high temperatures and fracture toughness in Zr-added alloys. 2 at%Zr-added alloy is superior to the base alloy and also well balanced compare with the other binary alloys in the various properties, strength at RT and high temperature, ductility at RT and fracture toughness.抄録全体を表示PDF形式でダウンロード (1203K) -
高橋 勝彦, 横山 総二郎, 浅田 實, 川上 正博1997 年 61 巻 12 号 p. 1358-1364
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーCO reduction of (Ni1−xMgx)O pellets was carried out to make the oxide particles dispersion strrengthened metal. The reduction rate of (Ni1−xMgx)O pellets was analyzed by an unreacted-core model. The microstructure of reduced mickel phase was observed by using SEM and TEM. The results are summarized as follows.
The reduction rate of the pellets with less than 5%MgO was larger than that of pure NiO, while that with more than 10%MgO was smaller. The well-sintered nickel phase was formed from pure NiO but the porous nickel was formed from (Ni1−xMgx)O solid solutions. The fine particles of magnesia were uniformly dispersed in the nickel phase reduced from (Ni1−xMgx)O. The diameter of them were 10∼40 nm. During the reduction, the increment of magnesia content in solid solution was observed at the reaction interface. The chemical reaction rate constant decreased remarkably due to the enrichment of magnesia content at the reaction interface. In addition, because this local enrichment results in an uneven distribution of reduction rate across the reaction interface, fine particles of magnesia were precipitated from this region in metallic nickel consequently.
It is seen that the metal containing the fine oxide particles can be obtained by the present method.抄録全体を表示PDF形式でダウンロード (1177K) -
志田 善明, 上月 康裕, 永田 辰夫1997 年 61 巻 12 号 p. 1365-1372
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーLong-term oxidation behavior of binary Ti-Al and ternary Ti-34.5 mass%Al based alloys with various element additions was studied at relatively low temperatures (1023 and 1073 K) in the laboratory air. The effect of added elements on the oxidation behavior was somewhat different from the previous results obtained at higher temperatures. The addition of Cr, V, Mn, and Fe (in this order) caused degradation in the oxidation resistance. Particularly, Cr was extremely detrimental; the oxidation rate of the Ti-34.5Al-1Cr alloy exceeds that of the Ti-20%Al binary alloy, probably causing a large doping effect in TiO2. On the other hand Nb, Mo and W were beneficial in the order, resulting in a parabolic oxidation behavior up to 3500 h. Differences in the effect between the three elements may be due to the differences in the morphology of Al2O3 formation within the inner scale.抄録全体を表示PDF形式でダウンロード (1786K)
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