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74 巻, 11 号
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解説論文
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宮内 彰彦, 岡部 徹原稿種別: 解説論文
2010 年 74 巻 11 号 p. 701-711
発行日: 2010年
公開日: 2010/11/01
ジャーナル フリーThe abundance of vanadium (V) in the earth's crust is 150 ppm; this is significantly larger than the abundance of nickel, zinc, or copper which are classified as common metals. However, V metal belongs to a set of “less-common metals” or “rare metals” because of the small production volume. This fact is partly due to its low concentration in its natural ores and the uneven distribution of its minerals. V metal is commercially produced by the aluminothermic reduction (ATR) of vanadium pentoxide (V2O5). The reduction product of the ATR process is a vanadium-aluminum (V-Al) alloy containing approximately 20 mass% of aluminum. Further purification process is required for obtaining pure V metal, used for the fabrication of functional materials such as hydrogen storage alloys. At this stage, an effective production process of pure V metal has not been established. Therefore, there is a strong requirement for the development of a simple and efficient process for the direct production of high-purity V metal and its alloy.
This paper reviews various types of processes for producing V metal and its alloys. These reduction processes are classified on the basis of the V compounds and reaction types, and their features are reviewed. Lastly, the future prospects for the development of new processes for the production of high-purity V metal are presented.
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論文
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海老原 祥秀, 国京 伸明, 神田 昌枝, 大山 龍一郎, 西 義武原稿種別: 論文
2010 年 74 巻 11 号 p. 712-717
発行日: 2010年
公開日: 2010/11/01
ジャーナル フリーCu-powders dispersed poly-methyl methacrylic acid (acrylic resin, PMMA) was prepared by solution-cast, which could easily control the dispersion ratio. The Cu addition gradually enhanced the electrical conductivity at less and more than the critical volume fraction (15.0±1.0 vol%Cu) in PMMA. The jump of electrical conductivity was observed by the Cu addition at the critical volume fraction. Although the result was mostly explained by the percolation theory, the critical Cu volume fraction to convert the high conductivity of PMMA composite is 4.0 vol% lower than that of ABS composites.
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～都市鉱石 TMR の枠組み構築～山末 英嗣, 南埜 良太, 沼田 健, 中島 謙一, 村上 進亮, 醍醐 市朗, 橋本 征二, 奥村 英之, 石原 慶一原稿種別: 論文
2010 年 74 巻 11 号 p. 718-723
発行日: 2010年
公開日: 2010/11/01
ジャーナル フリーIn this study, the total materials requirement (TMR) to recycle chemical elements from the urban ore by recycling (urban ore TMR, UO-TMR) has been compared with the TMR to extract the element from the natural ore by smelting (natural ore TMR, NO-TMR) in order to evaluate the urban ore grade on an equal footing with the natural ore. A framework of UO-TMR based on the NO-TMR framework is developed. To validate the developed framework, the UO-TMR of a laptop PC is estimated assuming gold, silver, copper, iron, aluminum, tantalum and indium are recycled. It is found that the UO-TMRs for gold, silver, copper, iron, aluminum and tantalum are lower than NO-TMR, but that for indium is higher. The ratio of “urban tailings” is at most 60% of the total, which is smaller than that of NO-TMR “tailings”. In contrast to the contributions of energy and material inputs for the recycling process, the contribution of transportation is not very large. For the UO-TMR of indium, the contribution of materials for recycling process is extremely large. The availability and scalability of UO-TMR are also discussed.
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楊 峰, 田 文懐, 中野 博昭, 辻 英昭, 大上 悟, 福島 久哲2010 年 74 巻 11 号 p. 724-732
発行日: 2010年
公開日: 2010/11/01
ジャーナル フリーNickel electrodeposition was galvanostatically conducted over the current density range 500-2000 A/m2 in unagitated sulfamate and Watt's solutions at 323 and 313 K, respectively, to examine the effect of current density and organic additives on the texture, crystal orientation, and hardness of the deposited Ni. The overpotential for Ni deposition increased by the addition of polyethylene glycol (PEG) or saccharin in both sulfamate and Watt's solutions. The degree of increase in the overpotential in a PEG-containing solution was larger than that in a saccharin-containing solution. Nickel deposited from an additive-free solution showed a morphology of field oriented texture type with the preferred orientation of the {100} plane, while Ni obtained from a PEG- or saccharin-containing solution had the unoriented dispersed type without a preferred orientation in the region of some current densities. The region of the current density that resulted in the unoriented dispersed type in Watt's solution was larger than that in a sulfamate solution. The particle size of the deposited Ni decreased with the addition of PEG and saccharin. The hardness of the deposited Ni increased with PEG and saccharin, and was higher for the unoriented dispersed texture than for the field oriented texture. In additive-containing solutions, the hardness of Ni deposited from Watt's solution was higher than that from a sulfamate solution.
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小山 真司, 大屋 一生2010 年 74 巻 11 号 p. 733-739
発行日: 2010年
公開日: 2010/11/01
ジャーナル フリーThe effect of acetic acid surface modification on the superficial oxide film that covers the solid-state bonded joint of tin has been investigated by conducting SEM and TEM observations of the interfacial microstructures and fractured surfaces. Acetic acid surface modification was carried out by boiling a tin surface in acetic acid for 900 s. Solid-state bonding was carried out in a vacuum chamber at a bonding temperature T of 403-483 K and a bonding pressure P of 7 MPa (bonding time=1800 s). It was observed that the bond strength increased with the bonding temperature, regardless of the acetic acid surface modification. Because of surface modification, bonded joints were obtained at a bonding temperature that was 40 K lesser than the typical temperature required, and the bond strength was comparable to that of the base metal. When the joint strength was much lower than the base metal strength, belt-like inclusions were found to be distributed in the interfacial region. As the joint strength increased with bonding temperature, these inclusions were coarsened, and their distribution density decreased. The increase in bond strength with bonding temperature corresponded well with the observed change in the size and density of the inclusions. This tendency was observed at a bonding temperature that was 40 K lesser than that of the joint that did not undergo surface modification. Therefore, it is believed that the joint that underwent surface modification possessed a high tensile strength despite having a low bonding temperature; this is because tin (II) acetate coheres at a temperature lower than required for the coherence of an oxide film, and the area of the metal-to-metal contact increased at a low temperature.
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三宅 修吾, 長野 恭子, 三宅 綾, 高松 弘行, 喜多 隆2010 年 74 巻 11 号 p. 740-745
発行日: 2010年
公開日: 2010/11/01
ジャーナル フリーSpatially resolved thermal conductivity of Cu6Sn5 intermetallic compounds (IMCs) formed in Sn-Ag-Cu lead free solder has been investigated by using a periodically modulated thermoreflectance (TR) method. The high spatial resolution has been achieved by focusing a modulated laser beam. The temperature response on the irradiated surface has been analyzed by calculating the phase lag of the TR signal as a function of the thermal diffusion length. We found that the boundary of IMCs influences the phase lag. Furthermore, the thermal conductivity of Cu6Sn5 was selectively measured by the TR method considering three-dimensional thermal diffusion model. The estimated thermal conductivity of Cu6Sn5 is 39 W/(mK) which is lower than 54 W/(mK) of Sn-3.5Ag-0.5Cu. Thus the micro-TR method is a powerful method to characterize the thermal conductivity of not only IMCs but also various complex materials.
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澤田 俊之, 柳谷 彰彦2010 年 74 巻 11 号 p. 746-750
発行日: 2010年
公開日: 2010/11/01
ジャーナル フリーShot peening is widely used for automobile parts such as springs and gears to improve fatigue strength. In general, high-hardness media is required for shot peening to high-hardness materials. Recently, shot peening to various tool steels such as cold and hot work tool steels and high speed tool steel has been investigated and is used in some applications, and improvements in fatigue strength and die life by the increase of compressive residual stress and hardness at their shot peened surface have been reported.
In this study, the properties of cold work tool steel shot peened by Fe-8%Cr-6.5%B (mass%) gas atomized powder (FeCrB powder) with HV 1200-class Vickers hardness and long life as shot peening media were examined. Quenched and tempered JIS SKD11 followed by shot peening by FeCrB and high speed steel powder sieved between 45 and 125 μm was used.
Vickers hardness and compressive residual stress of the shot peened JIS SKD11 surface by FeCrB powder were higher than these by high speed steel powder. As a result, JIS SKD11 shot peened by FeCrB powder showed excellent fatigue property, Charpy impact value and wear resistance property.
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杉岡 奈穂子, 北田 正弘2010 年 74 巻 11 号 p. 751-757
発行日: 2010年
公開日: 2010/11/01
ジャーナル フリーThe microstructure of woolen fiber dyed by the PbCrO4 yellow dyeing technique imported into Japan in the last Edo period has been investigated. The woolen fiber is dyed using lead acetate and potassium chromate. The color is measured with a spectrophotometer. The microstructures are observed using a scanning electron microscope and transmission electron microscope. The crystal structure is determined with an X-ray diffractometer. The composition is analyzed using an energy dispersive X-ray spectrometer. A thin film is fabricated by the focused ion beam method to observe the nanostructures. The cross section is flattened by ion milling to reduce the damage to the surface. The absorption edge at 558 nm (2.2 eV) is observed in the reflectance spectrum for lead chromate woolen threads. The edge agrees with that of PbCrO4. The dyestuff compounds, monoclinic and orthorhombic PbCrO4, are detected by X-ray diffraction analysis. The crystal compound PbCrO4 precipitates on the woolen fiber surface; and the length and width of the crystals are 0.2~1.2 μm and 0.05~0.4 nm, respectively. Chromium, lead and sulfur are detected from the inside of the fiber. referential precipitation is observed in the fiber, and most of the precipitates align along a specific place in the fiber. The precipitate distribution shows a correlation between the precipitation phenomenon and the woolen fiber structure, and also reveals the microstructures in the woolen fiber. Although the precipitate on the fiber surface is crystalline, nanometer-size precipitates in the fiber are amorphous.
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施 維, 醍醐 市朗, 松野 泰也, 足立 芳寛2010 年 74 巻 11 号 p. 758-765
発行日: 2010年
公開日: 2010/11/01
ジャーナル フリーRecently, recycling of rare metals has been of great interest because of the rapid growth in their demands. Substance flow analysis (SFA) is a useful tool to figure out the flow of substance in designated area. SFA is sometimes used to quantify the recycling potentials of the substances. However, few SFA has so far been conducted for rare metals. In this paper, we focused on Dy and conducted SFA of Dy in Japan. The end use of Dy was categorized into 4 groups; automobiles, electronic home appliances, factory automation and voice coil motor, which were further subdivided into 10 categories. We estimated time-series data about the domestic consumption and input of Dy in each end use during 1987-2008 in Japan using bottom-up approach. Stock in-use of Dy was estimated as the recycle potential by using the dynamic SFA, in which the time-series data and lifetime distribution of each end use were used. As a result, the stock in-use of Dy in Japan was estimated as approximately 890-1100 t in 2008. It was also found that, the amount of domestic input (170-220 t) was half of the amount of import (360-400 t) because a lot of Dy contained in final products were exported from Japan.
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石黒 三岐雄, 我妻 和明2010 年 74 巻 11 号 p. 766-770
発行日: 2010年
公開日: 2010/11/01
ジャーナル フリーThe method of separation and determination of zirconium carbide in Zr50Al10Ni5Cu30 bulk metallic glass matrix composites containing zirconium carbide particles has been developed.
The zirconium carbide was not dissolved though the metallic glass specimen was dissolved with 6 kmol•m−3 hydrochloric acid of the room temperature.
After complete dissolution of the metallic glass matrix specimen with 6 kmol•m−3 hydrochloric acid of the room temperature, the undissolved zirconium carbide was separated by filtration with the membrane filter having the pore size of 0.2 μm. The separated zirconium carbide was fused with the potassium hydrogen sulfate in the platinum crucible. The concentrations of zirconium, copper, aluminum and nickel in the filtrate and the insoluble residue were determined respectively by inductively coupled plasma-optical emission spectrometry.
The zirconium concentration in the filtrate and the insoluble residue were constant irrespective of the dissolution time. Copper, aluminum and nickel were not detected in the insoluble zirconium carbide.
It was confirmed that the zirconium carbide in the Zr50Al10Ni5Cu30 bulk metallic glass matrix had been quantitatively separated and determined.
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