巻号一覧
49 巻, 3 号
選択された号の論文の12件中1～12を表示しています
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仲田 清智, 高村 三郎, 多田 直文, 正岡 功1985 年 49 巻 3 号 p. 157-162
発行日: 1985年
公開日: 2008/04/04
ジャーナル フリーMagnetoresistivity changes caused by neutron irradiation at 5 K, annealing up to 300 K and cyclic irradiation are studied in copper and aluminuim stabilizer materials at 4.2 K. The radiation-induced resistivity in Al is about three times as large as that in Cu, and the resistivities in both Al and Cu are independent of the purity and the degree of cold-work of the samples. The radiation-induced magnetoresistivity of the high purity Cu with R.R.R. (R298 K⁄R4.2 K) of 1400 is larger than that of the impure Cu with R.R.R. of 300 and 280. The magnetoresistivities of the high purity Cu and Al with R.R.R. of 1500 increase with the magetic field. Magnetoresistivity change with the magnetic field in the irradiated Cu mostly follows Kohler’s rule, and that in the irradiated Al does not follow the rule at high magnetic fields. By the annealing at 300 K after the irradiation, the radiation-induced resistivity is completely annihilated in the Al, but about 20% of the resistivity retains in the full-annealed Cu, and the retained resistivity is accumulated during the cyclic irradiation. Though the accumulated resistivity in the cold-worked Cu is smaller than that in the full-annealed one, the resistivity before irradiation in the cold-worked samples is very large. From the above results, the full-annealed Cu with R.R.R. of about 300 is considered to be the best material as a stabilizer used under irradiation.抄録全体を表示PDF形式でダウンロード (924K) -
高橋 実, 石井 たかし, 石尾 俊二1985 年 49 巻 3 号 p. 163-167
発行日: 1985年
公開日: 2008/04/04
ジャーナル フリーAnnealing effects on the thermal expansion properties of amorphous Fe-B alloys have been investigated to clarify the structural relaxation in the amorphous state and the crystallization process. In an amorphous Fe88B12 alloy, the length contraction due to exhaustion of free volume was found to start from about 400 K and becomes 0.80×10−3 at 500 K, and the activation energy for this process was evaluated as about 30 kJ/mol. On the other hand, an appreciable change in the thermal expansion by annealing was not found in Fe83B17 and Fe75B25 alloys. These results are discussed in connection with the change in the atomic short range order with B concentration.抄録全体を表示PDF形式でダウンロード (714K) -
高橋 研, 斎藤 準, 高倉 敬一, 宮崎 照宣, 脇山 徳雄, 高橋 実1985 年 49 巻 3 号 p. 168-176
発行日: 1985年
公開日: 2008/04/04
ジャーナル フリーSm-Co alloy ribbons in the concentration range, 10-22 at%, were fabricated by a rapidly quenching from the melt using a single roller method. The hard magnetic properties were systematically examined for these ribbons. The continuous ribbons about 1 m in average length, 20-150 μm in thickness and 1-2 mm in width, were obtained by varing the ejection pressure of Ar gas in the range of 0.03-0.20 MPa, and the roll velocity, VR, in the range of 4.3-42.7 m/s. Magnetic hysteresis loops were measured using the V.S.M. for two kinds of specimens; (1) the ribbons with the same composition of alloy fabricated under various different preparation conditions and (2) the ribbons consisting of different alloy compositions produced in the same fabrication conditions. The dependences of the coercive force iHc and the maximum energy product (BH)max on the Sm concentration and also on the roll velocity were systematically clarified. In the cace of the SmCo5 alloy ribbons, iHc takes a maximum value, about 1200 kA/m, at VR≈18 m/s. This maximum value of iHc is nearly the same as that of the commercially used sintered SmCo5 magnets. The maximum value of (BH)max, about 70 kJ/m3, is obtained at VR≈10 m/s. This maximum value of (BH)max experimentally obtained is nealy one half of that for the sintered magnets. The concentration dependence of iHc and (BH)max revealed that the Sm concentration at which the maximum values of iHc and (BH)max were realized was about 18 at%. This content of Sm is about 2 at% more than the stoichiometric composition of SmCo5 compound. Experiments for the high field magnetizing using a pulse magnet (5570 kA/m) were carried out for these ribbons. Increment of (BH)max, about 20%, is observed in the case of the ribbons with the concentration about 18 at%Sm.抄録全体を表示PDF形式でダウンロード (1315K) -
高橋 研, 斎藤 準, 高倉 敬一, 宮崎 照宣, 脇山 徳雄, 高橋 実1985 年 49 巻 3 号 p. 177-186
発行日: 1985年
公開日: 2008/04/04
ジャーナル フリーStructure analysis by X-ray diffraction and precise metallographic observations by SEM were made for rapidly quenched Sm-Co alloy ribbons. The high temperature phase of Sm2Co17 compound was found in the composition range between 10 and 16 at%Sm. The SmCo5 phase was found in the Sm concentration above 16 at%Sm. According to observation results on the metallographic structure, the columnar structure in which c-axis was aligned parallel to the ejected direction of the ribbons was present in the ribbons fabricated at the relatively low roll velocity VR below 18 m/s. In the ribbons fabricated at the higher roll velocity VR>18 m/s, any columnar structure was absent, and only homogeneous spherical fine particles with random orientation of c-axis were present. The origin of the change in the coercive force iHc and the residual magnetization Mr with the roll velocity was discussed in connection with the change in the metallographic structure of the ribbons. As a result, the following were clarified: (1) The magnetization reversal process for the ribbons consisting of SmCo5 phase is ruled by the irreversible movement of 180° walls. (2) Increment of iHc and the decrement of Mr with increasing roll velocity on fabrication are caused by the decrease of the degree of c-axis orientation of grains and also by the structure change from the columns to fine spherical particles with random orientation. (3) iHc for the columns about 2 μm in diameter is nearly the same as that of the spherical fine particles with the single domain structure, even though the multidomain structure is realized in the columns.抄録全体を表示PDF形式でダウンロード (2725K) -
田上 耕司, 八尋 寛司, 森 寿敏, 松田 日出彦1985 年 49 巻 3 号 p. 187-195
発行日: 1985年
公開日: 2008/04/04
ジャーナル フリーTemperature (77-500 K) and strain rate (3×10−6-10−2 s−1) dependence of the yield and the flow stresses of powder metallurgical tungsten wires are mainly investigated. The former is marked and can be experimentally represented by Guyot and Dorn’s equation, σ∝σp[1−(T⁄T0)1⁄2] based on the Peierls mechanism. The latter is estimated exclusively from stress relaxation tests. The shape of stress relaxation curves plotted as logσ vs. log\dotεp is straight at any strain and temperature, giving a strain rate sensitivity parameter m[=(∂lnσ⁄∂ln\dotεp)T,ε] from its slope. The strain independent mean values of m are obtained to be 0.01-0.03 with a maximum at 300 K. These m values imply that the yield and the flow stresses do not so strongly depend on strain rate.
The variation of the Gibbs free energy ΔG with stress can be expressed by ΔG=A−Blnσ, assuming that the plastic strain rate during stress relaxation is given by the Arrhenius type equation. It becomes evident from the parameter B dependent on temperature that the short range obstacle profile for dislocation movement depends on temperature. Accordingly, the good arrangement of stress for temperature with Guyot and Dorn’s equation may be due to the apparent satisfaction of the present results with a profile derived from their model.抄録全体を表示PDF形式でダウンロード (2794K) -
崔 明勲, 及川 洪1985 年 49 巻 3 号 p. 195-202
発行日: 1985年
公開日: 2008/04/04
ジャーナル フリーTensile tests of commercially pure titanium, the grain size of which was about 0.1 mm, were conducted in argon at 843-1100 K under 3.3×10−6-3.3×10−2 s−1. The true strain-rate, \dotε, was related with the power law of the maximum (steady-state) stress, σs, which was corrected for straining under the constant true strain-rate; the stress exponent n was 4.36±0.13. The activation energy for steady-state deformation, Qc, was estimated as 184.4±1.2 kJ/mol, taking the temperature dependence of shear modulus into account. This value of Qc is close to that for the tracer diffusion. Dorn equation is applied to a polycrystalline alpha-titanium using diffusion coefficients given by Dyment (1980) and shear moduli given by Fisher and Renken (1964): A=3.2\genfrac()0pt+1.0−0.8×105 and n=4.20±0.07. The effect of grain size, d, was investigated in the range from 0.1 mm to 1.3 mm. The value of n does not depend on d. The factor A depends on d in fine-grained samples, but in coarse-grained samples, it becomes independent of d: A=7.0\genfrac()0pt+1.4−1.2×104. Coarse-grained alpha titanium is significantly weak in respect of the normalized strength as compared with ordinary hcp metals.抄録全体を表示PDF形式でダウンロード (1050K) -
榊 孝, 清水 要樹, 崎山 和孝1985 年 49 巻 3 号 p. 202-209
発行日: 1985年
公開日: 2008/04/04
ジャーナル フリーThe corrosion behaviour of various commercial alloys was studied by measurements of potentio-dynamic polarization curves, the change in corrosion potential with time and the average corrosion rate. The corrodent used was 48%NaOH solution at temperatures between 373 and 473 K, and the following results were obtained. The corrosion resistance of stainless steels was improved by adding nickel and chromium. Especially, immersion tests showed that ferritic stainless steels containing 27-30% chromium and austenitic stainless steels containing nickel more than 20% possessed excellent corrosion resistance. On the other hand, addition of molybdenum and copper to the stainless steels gave no protective effects as to the alkaline corrosion. When the corrodent was a 48%NaOH solution obtained by the diaphragm process, NaClO3 contained in the solution acted as an oxidizer. Its oxidation powder increased somewhat the tendency of the high chromium steels to become passive, but promoted dissolution of nickel.抄録全体を表示PDF形式でダウンロード (969K) -
榊 孝, 崎山 和孝1985 年 49 巻 3 号 p. 209-216
発行日: 1985年
公開日: 2008/04/04
ジャーナル フリーThe effect of Na2CrO4, NaBiO3 and NaClO3 on the corrosion of stainless steels has been investigated mainly by means of a potentio dynamic method and measurement of corrosion loss in 48%NaOH solution at 413 K. The presence of oxidative oxyanions in the caustic solution shifted the corrosion potential of steels to the noble direction. The oxidation power of such oxyanions increased with increasing concentration of them in the solution in the following order: ClO3−<BiO3−<CrO42−. The corrosion rates of stainless steels were decided by the action which shifted the corrosion potential to the active state or the passive state. Oxidative oxyanions possessed an inhibitive effect for the corrosion of stainless steels in caustic solutions.抄録全体を表示PDF形式でダウンロード (831K) -
朝田 誠一, 北田 正弘1985 年 49 巻 3 号 p. 217-223
発行日: 1985年
公開日: 2008/04/04
ジャーナル フリーThe effects of additive Ru on the corrosion resistance of magnetic Fe powders are investigated. Fe and Fe-Ru powders are prepared from acicular fine α-FeOOH powder by hydrogen reduction. The corrosion resistance of the powders is evaluated by the saturation magnetization loss in a humid air atmosphere (333 K, 90% relative humidity). The coercivity, the saturation magnetization and the squareness ratio of Fe-5 at%Ru powder are similar to those of Fe powder. Moreover, the saturation magnetization loss of Fe-5 at%Ru powder is only one fourth of that of Fe powder, when these powders are exposed to the atmosphere for 540 ks (150 h).
To clarify the effects of additive Ru on the corrosion resistance, corroded and uncorroded sputtered Fe-Ru thin films are also investigated with Auger electron spectroscopy and anodic polarization technique. A Ru-enriched layer is formed by selective oxidation of Fe near the Fe-Ru thin film surface. The natural anodic potential of the alloy film increases slightly with an increase in Ru concentration. It is thought that these relate to the improvement of the Fe powder corrosion resistance by additive Ru.抄録全体を表示PDF形式でダウンロード (1311K) -
松田 史朗, 杉本 克久1985 年 49 巻 3 号 p. 224-230
発行日: 1985年
公開日: 2008/04/04
ジャーナル フリーIn order to understand the changes of surface oxide films with cathodic polarization of an oxide-covered Ta electrode and with anodic polarization of a hydrogen-absorbed Ta electrode, the ellipsometric parameters have been measured in situ on Ta electrodes under anodic and cathodic polarization in a 0.5 kmol·m−3H2SO4 solution. Optical constants for the film-free surface and the hydrogen-absorbed surface of Ta were determined by tribo-ellipsometry and used to calculate the thickness and optical constants of surface films from measured values of ellipsometric parameters.
When a Ta electrode having an anodic oxide film was polarized to a cathodic potential, the transformation of the film was observed from change in extinction coefficient of the optical constant from zero to about 0.15, while its thickness did not change during prolonged cathodic polarization.
When a hydrogen-absorbed Ta electrode was polarized to an anodic potential, the discharge of hydrogen and the formation of anodic oxide film occurred simultaneously. The optical constant of the anodic oxide film formed on hydrogen-absorbed Ta was smaller than that formed directly on Ta metal.抄録全体を表示PDF形式でダウンロード (954K) -
山内 勇, 大中 逸雄, 川元 暁, 福迫 達一1985 年 49 巻 3 号 p. 231-237
発行日: 1985年
公開日: 2008/04/04
ジャーナル フリーRapidly solidified Al-Si alloy powders containing Si from 7.1% to 23.7% produced by the Rotating-Water-Atomization Process was hot-extruded and the mechanical properties were examined. The results are summarized as follows:
(1) Rapidly solidified powders were easily extruded at 593 K and 673 K without blister, and its surface quality was smoother, especially for higher Si alloys, than that of the cast material similarly extruded.
(2) Si particles were precipitated and grew during the hot extrusion and their size depended on the extrusion temperature.
(3) The tensile strength and hardness were much higher than the cast and extruded material without remarkable loss of elongation. Finely dispersed Si was evidently very effective in improving the tensile strength of Al-Si alloy powder extrusion. The tensile strength of Al-23.7%Si extruded at 593 K was about 360 MPa and its elongation was about 5%. The strength increased with decreasing extrusion temperature.抄録全体を表示PDF形式でダウンロード (3301K) -
田口 悟1985 年 49 巻 3 号 p. 238-242
発行日: 1985年
公開日: 2008/04/04
ジャーナル フリーIn general, decrease in sheet thickness decreases the core loss due to the decreased classical eddy current loss. However, at small thickness, surface pinning effects on the domain wall movement become dominant. The proportion of anomalous eddy-current loss arising from the domain wall movement is as much as about 45% of the total loss at the commercial frequencies, 50 and 60 Hz, but the relationship between the anomalous loss and the sheet thickness has not been clarified yet. The tensile stress imparted by the inorganic coating decreases the core loss, but there is no evaluation of the effect of thickness with tensile stress on the core loss.
The systematic investigation has been made on specimens with various sheet thickness, for which the chemical polishing technique has been used.
The decrease in core loss with tensile stress was greater for smaller thickness. Especially, for B8=1.77 T, the applied tensile stress increased the core loss for larger thickness and decreased the core loss for smaller thickness. The greater tensile stress decreases the domain wall spacing. The decrease in domain wall spacing with tensile stress was greater for larger thickness than for smaller thickness.
The magnetostriction measurements indicated that the 90° domain volume at a demagnetized state was smaller for smaller thickness, and the volume of new 90° domains created at intermediate inductions due to the need of reducing magnetostatic energy was smaller for smaller thickness. The applied stress decreased the 90° domain volume at a demagnetized state and suppressed the formation of 90° domains at intermediate inductions. The magnetostatic energy due to free poles appearing on the surface was less effective in reducing the domain wall spacing and creating 90° domains for smaller thickness.
The decrease in core loss with stress was due mainly to the decreasing supplementaly domains, especially 90° domain volume. The behavior of magnetization for a smaller thickness sheet was similar to that for a larger thickness sheet with larger B8.抄録全体を表示PDF形式でダウンロード (1145K)
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