巻号一覧
71 巻, 12 号
選択された号の論文の8件中1～8を表示しています
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藤田 浩示, 高原 良博2007 年 71 巻 12 号 p. 1071-1074
発行日: 2007年
公開日: 2007/12/01
ジャーナル フリーRecently, research and development using ultraviolet rays is being conducted in the bioscience field. In such R&D, expensive quartz glass is most often used as the ultraviolet transmitting material. The authors have been studying the use of inexpensive soda-lime glass as an alternative to quartz. In this study the authors investigated the effects of iron oxide and titanium oxide, which are found in raw materials, and crucible materials on the ultraviolet transmission properties of soda-lime glass. It was found that by reducing the amount of Fe2O3 and TiO2 contained in raw materials as impurities, it was possible for soda-lime glass to achieve high ultraviolet transmissivity. Reducing the amount of iron oxide turned out to be an especially effective way to improve ultraviolet transmissivity.
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福本 倫久, 遠藤 俊貴, 松田 康宏, 原 基, 成田 敏夫2007 年 71 巻 12 号 p. 1075-1079
発行日: 2007年
公開日: 2007/12/01
ジャーナル フリーThe formation of a coating layer consisting of Ni aluminide containing Zr on a Ni-10 at%Cr-8 at%Al alloy substrate was attempted by the electrodeposition of Zr, Ni and Al. The cyclic oxidation resistance for the alloys covered with this coating was then evaluated. Ni was deposited by aqueous solution electrolysis. Zr and Al were deposited by molten salt electrolysis. For the sample treated with the Ni deposition, followed by the Al deposition, a layer consisting of Ni2Al3 was uniformly formed. On the other hand, for the sample treated with the Zr deposition, followed by the Ni and Al depositions, a Ni-Zr alloy layer and a Ni2Al3 layer were formed in that order from the substrate alloy. The cyclic oxidation test showed that for the untreated sample and the sample only with Ni and Al depositions, a mass reduction due to exfoliation of a scale took place during the initial oxidation period. For the sample treated with the Zr deposition for 0.03 and 0.24 ks, followed by the Ni and Al depositions, a mass reduction was observed during the course of the oxidation test. However, for the sample treated with the Zr deposition for 0.18 ks, no mass reduction was observed. The result of a cross-sectional observation for this sample treated with the Zr deposition for 0.18 ks after the 5-cycle oxidation test showed that the Ni-Zr alloy layer disappeared and a wedge-shaped α-Al2O3 scale was formed on the Ni aluminide layer. Consequently, it was considered that for this sample, the Zr in the Ni-Zr alloy layer diffused into the Ni aluminide layer, contributing to an improvement in the exfoliation resistance of the Al2O3 scale.
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石井 勝也, 尾崎 良太, 金子 賢治, 増田 正孝2007 年 71 巻 12 号 p. 1080-1083
発行日: 2007年
公開日: 2007/12/01
ジャーナル フリーCorrosion test of AIN99 (99.99% pure aluminum) and A3003 (Al-Mn Alloy) in deoxidized (O2<0.1 ppm) pure water was conducted at the different temperatures. Although the incubation period, from the beginning of the test until the corrosion rate dramatically increased, was varied depending on temperature, it was not affected much by the composition of the material. It was also found that the corrosion rate changed remarkably depending on the temperature and the composition of the material after the incubation period; the corrosion rate of AIN99 was about three times faster than that of A3003. This was not caused by the speed of reaction of aluminum and water on the aluminum surface. AIN99 corroded all over the surface, while A3003 corrodes partially because Mn and Cu are distributed and the corroded area is small. However, the amount of corrosion was almost the same at the saturated condition, whereas the corrosion rate changes depending on the temperature and the composition of the material. This was because the corrosion continued until corrosion products accumulate to the same level on the surface. Accordingly, it become clear that when corrosion rate was fast, corrosion time was short; on the other hand, corrosion time was long when corrosion rate was slow.
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三原 武, 阿部 弘亨, 園田 健2007 年 71 巻 12 号 p. 1084-1088
発行日: 2007年
公開日: 2007/12/01
ジャーナル フリーFormation of subdivided grains and coarsened bubbles in uranium dioxides under high burn-up conditions in nuclear power plants deteriorate the performance of nuclear fuels. To clarify its mechanism, heavy ion irradiations in cerium dioxide followed by Raman spectroscopy, X-ray diffractometry and electron microscopy (SEM) were performed. At the early stage of irradiations, increase in the lattice constant and shift in the F2g peak position were observed presumably indicating accumulation of oxygen vacancies. Further irradiation enhanced recombination or clustering of vacancies depending on the irradiation temperature. The behaviors affect the surface morphology of the sample as well. Especially above 1000K, characteristic changes in Raman spectra and surface features were detected, presumably attributable to remarkable diffusion of vacancies. The relation between displacement of F2g position and electronic energy deposition of incident ions was observed, suggesting the role of electronic excitations on the formation of oxygen vacancies in cerium dioxide.
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上宮 成之, 英 敬信, 小島 紀徳2007 年 71 巻 12 号 p. 1089-1093
発行日: 2007年
公開日: 2007/12/01
ジャーナル フリーSi3N4 fine particles covered with deposited SiC ultrafine powder, denoted as SiC/Si3N4 composites, with excellent sinterability were prepared by an ultrafine powder coating reactor using thermal CVD technique. Reactant gases used were monosilane and ethylene. The CVD reactor was designed to accelerate homogeneous nucleation reaction. The effects of reactant gas flow rate ratio, C/Si, and reaction temperature on C2H4 conversion, C content in the deposited ultrafine powder and C selectivity were investigated. The CVD conditions were optimized to form stoichiometric ultrafine powder. The XPS results of ultrafine powder predict the synthesis of stoichiometric SiC. The required conditions for the sintering of the produced SiC/Si3N4 composites were drastically milder than that for a conventional sintering process for commercial Si3N4 fine particles. The application of our CVD reactor will be expected to the preparation of various composite particles with easy sinterability.
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川森 重弘, 町田 輝史2007 年 71 巻 12 号 p. 1094-1101
発行日: 2007年
公開日: 2007/12/01
ジャーナル フリーIn order to improve the mechanical properties of magnesium, dispersion strengthening with α-alumina particles (pAl2O3) is experimentally investigated as an application of powder metallurgy. The trial process consists of milling, compacting and hot-pressing. The microstructure of hot-pressed discs of magnesium composites were investigated using optical microscopy, scanning electron microscopy, x-ray diffraction (XRD) and electron probe micro analysis. The density, surface hardness, and maximum bending stress for deflection were also measured. All of the mechanically alloyed (MA) prepared powders were composed of only magnesium (Mg) and alumina (Al2O3). Although the particle size of the MA powders varied, the mean values were approximately 80 μm and were approximately the half size of the raw Mg powder. Not only Mg powder, but also pAl2O3 became finer with processing, and the pAl2O3 was almost uniformly dispersed in the Mg powder. In addition, the fine pAl2O3 was almost uniformly dispersed within the Mg of the pAl2O3 dispersion strengthened (ODS) magnesium discs. For all discs, a small quantity of magnesium oxide (MgO) was identified along with Mg and Al2O3. However, in only the 22.7 vol% pAl2O3/Mg disc, an XRD peak assigned to an Al-Mg intermetallic compound (Al12Mg17) was detected, in addition to Mg, Al2O3 and MgO. It is proposed that Al12Mg17 was produced by the solid-state reaction of Mg and Al2O3, and appeared at the interface between the regions of only Mg and regions where pAl2O3 is dispersed in Mg. The density of the discs was above the theoretical density for all pAl2O3 content; the density for the highest pAl2O3 content of 22.7 vol% was approximately 0.8 times greater than that of practical Al alloys. The 22.7 vol% pAl2O3 disc had a maximum hardness value of 280 HV. This value is much higher than that of both pure Mg ingot and AZ91D. The maximum bending stress decreased with an increase in the pAl2O3 content. The reason for this is considered to be that the discs become harder and more brittle, and voids are easier formed in the discs. Therefore, cracks that are generated on the specimen surface propagate easier.
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広中 直人, 井上 恵介, 神田 昌枝, 西 義武2007 年 71 巻 12 号 p. 1102-1106
発行日: 2007年
公開日: 2007/12/01
ジャーナル フリーAn effect of water absorption on Charpy impact value has been studied for a carbon fiber reinforced polymer (CFRP). Water submersion improves the Charpy impact value, although it softens the CFRP. The Charpy impact value of water submersed CFRP for 2×105 s at 373 K is about 8% higher than that before the treatment. The water submersion increases the mass because of water absorption into the CFRP sample, although hardening agent dissolves into the distilled water.
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安堂 正己, 若井 栄一, 大久保 成彰, 荻原 寛之, 澤井 友次, 大貫 惣明2007 年 71 巻 12 号 p. 1107-1111
発行日: 2007年
公開日: 2007/12/01
ジャーナル フリーMicro-hardness was measured for irradiated F82H steels by single (10.5 MeV Fe3+) , dual (10.5 MeV Fe3+ and 1.05 MeV He+) and triple (10.5 MeV Fe3+, 1.05 MeV He+ and 380 keV H+) beams at the TIARA facility in JAEA. The extra component of radiation hardening due to helium and hydrogen was hardly detected in dual/triple beams irradiation at 543 K and 633 K with comparatively low doses, while that due to helium was slightly occurred in dual beams (10 appmHe/dpa) irradiation at 633 K with higher doses up to 90 dpa. As increased the ratio of He/dpa (from 10 to 100 appmHe/dpa), the extra-hardening due to helium was increased. The microstructures in single/dual (10 appmHe/dpa) ion beam irradiated F82H steels consisted of interstitial loops and defect clusters at 50 dpa. However, at a higher ratio of He/dpa (100 appmHe/dpa), nano-voids were also observed in dual ion irradiated F82H.
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