巻号一覧
55 巻, 6 号
June
選択された号の論文の11件中1～11を表示しています
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研究
研究
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近藤 克哉, 油座 健二, 和田 光司, 大橋 修2008 年 55 巻 6 号 p. 401-407
発行日: 2008年
公開日: 2008/11/19
ジャーナル オープンアクセスIn pulsed electric current bonding, local heating at the contact area is accelerated. As the results, it is afraid that the powder as interlayer materials of joints is dispersed during the bonding. In this study 6063Al joints using powder as interlayer were formed at various bonding conditions such as powder (composition, mass), bonding pressure and electric wave (frequency, duty ratio). The powder loss and melted area at bonded joints were investigated to clarify the behavior of powder.
It was found that the powder is dispersed and melted around bonded interfaces during the pulsed electric current bonding. Powder loss ratio and melted area ratio at the joints increase with the increase of powder mass, initial current, duty ratio, and the decrease of bonding pressure. Phenomena of dispersion and melting using powder as interlayer are not affected by the current frequency and powder composition. The phenomenon of powder dispersion depends on the gas emission of H2O and H2 from powder. The decrease of powder mass and the initial current, and the increase of bonding pressure are recommended in the selection of bonding conditions to decrease the gas emission.抄録全体を表示PDF形式でダウンロード (1315K) -
Masahiro Yasukawa, Toshio Kono2008 年 55 巻 6 号 p. 408-414
発行日: 2008年
公開日: 2008/11/19
ジャーナル オープンアクセスAn oxalate coprecipitation method was applied to prepare dense ceramics of perovskite-type Sr1-xBaxPbO3 solid solutions with x = 0.0∼0.5, and the electrical conductivity and Seebeck coefficient were measured at high temperatures to estimate the thermoelectric power factors. Sr-Ba-Pb oxalates were coprecipitated from starting nitrate solutions with molar ratios of metallic ions controlled to Pb/Sr1-xBax = 1.05 and calcined at 700°C to obtain fine oxide powders. The small amount of PbO particles, which were dispersed well in the calcined powders composed mainly of SrPbO3 and BaPbO3, formed liquid phase during the sintering and led to the formation of the dense Sr1-xBaxPbO3 ceramics. The thermoelectric power factors of the Sr1-xBaxPbO3 ceramics with x = 0.0∼0.5 were estimated to be 1.0×10−4∼3.6×10−4 Wm−1K−2 in the temperature range 373∼1073 K and the value was maximized for the Sr0.7Ba0.3PbO3 ceramic. This study suggests that the present oxalate coprecipitation method is a simple and useful way to prepare dense Sr1-xBaxPbO3 ceramics showing comparatively high thermoelectric power factors.抄録全体を表示PDF形式でダウンロード (932K) -
山元 洋, 西尾 博明, 西崎 広紀2008 年 55 巻 6 号 p. 415-422
発行日: 2008年
公開日: 2008/11/19
ジャーナル オープンアクセスAn experiment was carried out to investigate the effect of Al2O3 substitution, molar ratio n {=Fe3+/(Co2++Ni2++Al3+)}, concentration of alkali, and inflowed time of alkali on the magnetic and physical properties of Co-Ni-Al system spinel ferrite fine particles prepared by the chemical coprecipitation method without post-annealing. The chemical coprecipitation compositions were chosen according to the formula (CoO)0.5(NiO)0.5−x(Al2O3)0.5x·n/2(Fe2O3), where x varied between 0 and 0.5 and n varied between 1.75 and 2.25. The typical magnetic properties were saturation magnetization σs=54.5×10−6 Wb·m/kg, residual magnetization σr=28.9×10−6 Wb·m/kg, coercivity HcJ =531.6 kA/m. To remove the superparamagnetic substance, the coprecipitation fine particles were etched with dilute sulfuric acid. As a result, in the (CoO)0.5(NiO)0.4(Al2O3)0.01·(Fe2O3) composition, when the excess NaOH and inflowed time were 0.5 mol and 1 s, respectively, the following magnetic and physical properties were obtained: σs=75.5×10−6 Wb·m/kg, σr=57.1×10−6 Wb·m/kg, HcJ=939.8 kA/m, K1=16.0×104 J/m3, K2=−6.3×104 J/m3, and HA=3.20 MA/m.抄録全体を表示PDF形式でダウンロード (1032K)
研究速報
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白井 孝, 安岡 正喜, 杵鞭 義明, 堀田 裕司, 粂 正市, 渡利 広司2008 年 55 巻 6 号 p. 423-427
発行日: 2008年
公開日: 2008/11/19
ジャーナル オープンアクセスIn conventional ceramics processing, a large amount of organic binder is employed to maintain shapes of green compacts. The development of a binder-free forming technology makes it possible to eliminate the binder burnout process, leading to decreases in energy and resources relating to the manufacturing, and generates a smaller environmental burden. Recently, we developed a novel ceramic forming process by surface hydration of particles through microwave irradiation. In this process, the irradiating a green body with microwaves enhances the hydration reaction between the water and the particle surfaces, creating surface aluminum trihydroxides structure of adjacent particles that bind together tightly. The key point of improvement in binding strength on this process was enhancement of surface hydration reaction. In this work, we investigated that the effects of mechanical surface treatment on the hydration ability of alumina powder surfaces. Furthermore, the mechanical property of alumina green body prepared by this forming method was discussed.抄録全体を表示PDF形式でダウンロード (593K)
研究
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畠山 敦, 児島 克典, 守上 英寿, 神崎 壽夫2008 年 55 巻 6 号 p. 428-433
発行日: 2008年
公開日: 2008/11/19
ジャーナル オープンアクセスLiMn1/3Ni1/3Co1/3O2 cathode materials were successfully synthesized by simple and optimized solid-state reaction method. A mixture of MnO2, Ni(OH)2, Co(OH)2 and Li2CO3 with propylene glycol (PG) for grinding aid was ball-milled without any solvent and then calcined. The result of XRD analysis showed that the ball-milled powder was almost amorphousized and the calcined powder was identified as LiMn1/3Ni1/3Co1/3O2. EPMA analysis indicated the powder synthesized without PG contains a lot of Mn-rich particles. The effect of the addition of PG was obvious and it made the homogeneity of three transition metals and electrochemical performance dramatically improved. The 1st discharge capacity of the synthesized sample without PG showed 151.9 mAh/g in the voltage range of 2.6-4.3 V (versus Li+/Li) at the current density of 0.2 mA/cm2 and that with PG showed 160.8 mAh/g.抄録全体を表示PDF形式でダウンロード (1224K)
特集：粉末の製造技術とその応用
総報
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中村 尚道2008 年 55 巻 6 号 p. 436
発行日: 2008年
公開日: 2008/11/19
ジャーナル オープンアクセスPDF形式でダウンロード (112K)
研究
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董 偉, 平塚 雄大, 三浦 彩子, 鈴木 拓明, 衣 明輝, 増田 聡, 高木 健太, 川崎 亮2008 年 55 巻 6 号 p. 437-445
発行日: 2008年
公開日: 2008/11/19
ジャーナル オープンアクセスPreparation of high purity mono-sized silicon particles by Pulsated Orifice Ejection Method (POEM) was investigated. The results of simulation show that a large contact angle between silicon and orifice is necessary for particle formation on processing by POEM. Mono-sized silicon particles can be prepared with quartz orifice and tundish within in a wide variety by POEM. Analyses by Scanning Electron Microscope (SEM) and Orientation Image Microscope (OIM) show that the obtained silicon particles can be divided into two kinds according to their surface morphology and microstructure. One is grape-fruit type silicon particles, which are polycrystalline and consist of many grains mainly in random boundaries, and the other is lemon type, which consists of only two or three grains in twin boundaries with cross-sections sometimes found to be single crystal. Measurements of electrical resistivity on polycrystalline ingots formed in the same conditions as silicon particles show p-type behavior with a room-temperature electrical resistivity in the range 15∼60 Ωcm and carrier concentration less than 2×1016 cm−3 that are suitable for solar cell.抄録全体を表示PDF形式でダウンロード (1752K) -
田中 学, 渡辺 隆行2008 年 55 巻 6 号 p. 446-451
発行日: 2008年
公開日: 2008/11/19
ジャーナル オープンアクセスThe purpose of this paper was to investigate the growth mechanism of the Sn-Ag nanoparticles prepared by Ar-H2 arc. The effects of the H2 concentration in the arc, initial composition of raw materials, and gas flow rate of circulation gas on particle diameter was investigated. Numerical analysis was conducted for the growth process with nucleation and co-condensation. Tin vapor was consumed by nucleation and condensation, followed by the condensation of silver vapor. Tin and silver were well synthesized in a liquid state in the co-condensation process since the particles grow at higher temperature than the melting point of Sn-Ag alloy.抄録全体を表示PDF形式でダウンロード (1124K) -
岩岡 拓, 中村 満2008 年 55 巻 6 号 p. 452-458
発行日: 2008年
公開日: 2008/11/19
ジャーナル オープンアクセスMg-Al-Zn type mixed powder was mechanically alloyed (MA) by using a planetary ball mill under Ar atmosphere. The MA powders were sintered by vacuum hot pressing (HP). The change of constituent phase of HP materials was examined by XRD and FE-EPMA. Its mechanical properties were evaluated by Vickers hardness and compression tests. HP material was obtained by processing MA powder with mean particle size of 5.6μm at 673 K for 18 ks. Its hardness and 0.2% proof strength became HV164 and 546 MPa, respectively. It is considered that this HP material shows high mechanical properties due to the fine dispersion of particles of Mg17Al12 phase.抄録全体を表示PDF形式でダウンロード (1723K) -
松原 慶明, 柳本 勝, 川崎 亮2008 年 55 巻 6 号 p. 459-463
発行日: 2008年
公開日: 2008/11/19
ジャーナル オープンアクセスThe formability and sintering behavior of Ni60Nb15Ti20Zr5 metallic glass powder prepared by gas atomizing was investigated using precise hot press equipment. The structure of atomized metallic glass powder depended on its particle size, and only glassy phase was observed when the particle size was under 53μm. The glass transition temperature (Tg), crystallization temperature (Tx), and supercooled liquid region (ΔTx=Tx-Tg) of the Ni-based metallic glass powder was 838 K, 888 K and 50 K, respectively.
The hot press sintering under the precise control of temperature and pressure was conducted. The densification behavior depended on only working temperature, and the Ni-based metallic glass powders were consolidated to nearly full density by hot press sintering with working temperature range 863-883 K. On the other hand, the crystallization behavior depended on working time as well as working temperature. In the experimental study this time, the hot press condition achieving both full densification and no crystallization was temperature of 868 K and pressure of 200 MPa. The sintered body of full densification and no crystallization exhibited high corrosion resistance nearly equal to Alloy C-276.抄録全体を表示PDF形式でダウンロード (1139K) -
益岡 佐千子, 新見 義朗2008 年 55 巻 6 号 p. 464-469
発行日: 2008年
公開日: 2008/11/19
ジャーナル オープンアクセスIn order to accelerate the sintering of Al-bronze powder covered with the oxide film in the hydrogen atmosphere containing high amount of nitrogen, we added phosphorus in the form of the phosphorus alloy in addition to Al-Ca fluoride the effect of which we reported in the previous paper. Al-bronze powder which was well sintered and formed the sintered compacts with higher strength even in the atmosphere containing high amount of nitrogen was obtained by adding over 0.2 mass% phosphorus. In the wear test of the above sintered compacts, it was found the dynamic friction coefficient and the wear rate of the Al-bronze sintered compacts were nearly half of those of Sn-bronze, and furthermore the wear rate of the Al-bronze sintered compacts decreased remarkably by dispersing 3 mass% of graphite.抄録全体を表示PDF形式でダウンロード (1884K)
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