材料
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
48 巻 , 6 号
選択された号の論文の21件中1~21を表示しています
  • 川崎 充晴, 田部 勢津久, 田中 勝久, 邱 建栄, 平尾 一之
    1999 年 48 巻 6 号 p. 531-534
    発行日: 1999/06/15
    公開日: 2009/06/03
    ジャーナル フリー
    Long lasting phosphorescence has been observed in CaO-Al2O3-SiO2 glasses doped with Eu2+ and Nd3+ after irradiation with an Hg lamp. The emission is due to the 4f-5d transition of Eu2+. The phosphorescence wavelength varies from 500 to 600nm, depending on the glass composition. The variation of phosphorescence wavelength is caused by the change of environment around Eu2+ ions with glass composition. Analyses of thermoluminescence glow curves reveal that the depth of electron or hole trap level which contributes to the phosphorescence process ranges from 0.50 to 0.81eV. It is thought that these are suitable values for the occurrence of thermoluminescence at around room temperature which results in the long lasting phosphorescence.
  • 若杉 隆, Michael C. WEINBERG, 大田 陸夫
    1999 年 48 巻 6 号 p. 535-540
    発行日: 1999/06/15
    公開日: 2009/06/03
    ジャーナル フリー
    The crystallization behavior of Na2O-SiO2 glasses was studied by Differential Thermal Analysis(DTA). The crystallization peak temperature (TC) increased with an increase of SiO2 content. For the quenched glasses, homogeneous nucleation was dominant in the low SiO2 composition, while surface nucleation was dominant in the composition higher than 55mol%SiO2. The heat treatment at the temperatures between 653 and 773K reduced TC due to the nucleation during heat treatment. The decrease of TC corresponds to the increase of the number of nuclei in the glass sample for DTA measurement. The ratio of crystallization peak temperature to liquidus temperature was used to evaluate the thermal stability of glasses. It was found that this parameter was a good linear relationship with the critical cooling rate for glass formation.
  • 樋口 宏司, 林 君山, 宮本 欽生, 廣田 健, 山口 修, 梅田 一徳, 田中 章浩, 山本 雅章, 田中 良平
    1999 年 48 巻 6 号 p. 541-545
    発行日: 1999/06/15
    公開日: 2009/06/03
    ジャーナル フリー
    Symmetrically graded materials of the Al2O3-BN/TiC/Ni were fabricated by SHS/HIP. High residual compressive stresses were produced in the outer layer due to the thermal expansion mismatch between the outer Al2O3-BN ceramic and the inner TiC/Ni cermet layer. The dispersion of BN in the Al2O3 layer increased the residual stress to higher levels than that induced in the Al2O3/TiC/Ni system. The BN has the layer structure with cleavage faces. The tribological properties of the outer Al2O3-BN layer were investigated at room temperature and 500°C in air. The friction coefficient of the outer layer was lower than that of monolithic Al2O3, especially at 500°C. The residual compressive stress was found to improve wear resistance of the surface layer.
  • 中平 敦, 赤水 宏, 木島 弌倫
    1999 年 48 巻 6 号 p. 546-549
    発行日: 1999/06/15
    公開日: 2009/06/03
    ジャーナル フリー
    CrSi2 based composites were fabricated by the pulse electric current sintering (PECS) technique and normal sintering technique. The sintering behaviors for these CrSi2 based composites were mainly investigated. The dense CrSi2 based composites with the addition of 5-50mol%NbSi2 were obtained at 1100°C by PECS technique, although not by the normal sintering technique even at 1400°C. Furthermore the relative densities of CrSi2/NbSi2 composites prepared by the PECS decreased with the sintering temperature. Young's modulus for these CrSi2/NbSi2 composites was evaluated. The microstructure of these CrSi2/NbSi2 composites was observed mainly by scanning electron microscopy. NbSi2 particles were homogeneously dispersed in the CrSi2 matrix.
  • 加藤 昌宏, 鵜沼 英郎, 鈴木 傑, 高橋 実
    1999 年 48 巻 6 号 p. 550-553
    発行日: 1999/06/15
    公開日: 2009/06/03
    ジャーナル フリー
    Addition of Mg into (Al, Cr)2O3 pigments significantly varied their colors. The Mg-added pigments consisted of (Al, Cr)2O3 corundum phase (C-phase) and Mg(Al, Cr)2O4 spinel phase (S-phase). In order to obtain data for the evaluation of the Cr contents in the C-and S-phases, (Al1-xCrx)2O3 corundum and Mg (Al1-xCrx)2O4 spinel both with x ranging from 0 to 1 were synthesized, and their lattice constants were measured by the XRD method. Lattice constants of the C-phase in the pigments prepared from (0.9-x)mol Al2O3, 0.1mol Cr2O3 and x mol MgCO3 were independent of the Mg content, and the Cr concentration of the C-phase in each pigment was determined to be 10mol%. On the other hand, a lattice constant of the S-phase decreased with the increase in the Mg content. Using the lattice constant data of the synthesized spinel and corundum, it was shown that the Cr content of the S-phase decreased with the increase in the Mg content. It was concluded that the color variations caused by the Mg addition into (Al, Cr)2O3 pigments were attributable to changes of the Cr content of the S-phase.
  • 塩野 剛司, 佐藤 良二, 塩見 治久, 皆木 卓士, 西田 俊彦
    1999 年 48 巻 6 号 p. 554-558
    発行日: 1999/06/15
    公開日: 2009/06/03
    ジャーナル フリー
    Forsterite, Mg2SiO4, precursor was synthesized from alkoxide solution containing MgO powder with average particle sizes of 0.1, 0.05 or 0.01μm. Effects of the particle size of MgO and milling of the precursor on the crystalline phase of precursors and calcined powders were examined. The obtained slurry was very stable. The precursor prepared with 0.01μm MgO was identified as amorphous. Calcining temperature of 1000°C was enough to make monolithic forsterite powder. With increase in particle size of MgO, however, MgO was distinctly identified in the precursor. Calcination of this precursor at 1200°C did not yield monolithic forsterite powder. MgO remained in the calcined powder. In order to eliminate the remaining MgO, the precursor was ball-milled with the planetary milling equipment. It was recognized that such milling was effective to eliminate the MgO and lower the crystallization temperature to forsterite.
  • 高橋 昌男, 渡辺 巌, 原田 誠, 溝口 康彦, 宮永 崇史, 柳瀬 悦也, 吉川 信一
    1999 年 48 巻 6 号 p. 559-565
    発行日: 1999/06/15
    公開日: 2009/06/03
    ジャーナル フリー
    The conversion electron yield (CEY)-XAFS spectra have been compared with those measured by the transmission method for ceramics powders and metal alloys. It has been pointed out from the comparison of Ti K-XAFS spectra of Ti metal foil and sheet that simple cleaning of specimen and elimination of surface oxides are necessary before the CEY-measurement to obtain the bulk information because the CEY method is surface sensitive. The amplitude of the CEY-EXAFS oscillation was somewhat smaller than that of the transmission-EXAFS oscillation for powder and foil samples, suggesting that one should take care of the evaluation of the EXAFS parameters such as the coordination numbers and the Debye-Waller factor on analyzing the local structure using the CEY-XAFS. It has been found from the analysis of both Ni K-XANES and K-EXAFS of NiO powder that the non-stoichiometry δ in NiO1+δ increases in the vicinity of the surface. At such higher energy region as In and Eu K-edge, the CEY method appears to have potential to the XAFS measurements, especially for either samples which cannot be pulverized or the situation where one cannot prepare the samples with adequate concentration. The signal-to-background ratio SB for the CEY-XAFS is also discussed; SB seems to be affected by at least two factors, ie, the Auger electron emission probability and the surface condition of specimen for K-absorption edge, while SB at LIII-absorption edge is mostly small in spite of quite large Auger electron emission probability.
  • 大内 宏, 塚本 真太郎, 山野辺 陽介, 森下 利教
    1999 年 48 巻 6 号 p. 566-570
    発行日: 1999/06/15
    公開日: 2009/06/03
    ジャーナル フリー
    Solid solution ceramics of the system xPb(Sc1/2Nb1/2)O3-yPbTiO3-zPbZrO3, where x=0-0.4, y=0.3-0.6, z=0-0.7, x+y+z=1, were prepared by the solid state reaction of powder materials. The density, dielectric and piezoelectric properties and crystal structures of sintered body were studied. The system was composed of three crystal phases at room temperature: the tetragonal, rhombohedral and orthorhombic. Sintering of the system xPb(Sc1/2Nb1/2)O3-yPbTiO3-zPbZrO3 was much easier than that of each terminal compositions, and well sintered ceramics were obtained for the composition near the morphotropic transformation.Piezoelectric ceramics with high dielectric constants and high radial coupling coefficient, kr, and low mechanical quality factor were obtained for the compositions near the morphotropic transformation. Pb(Sc1/2Nb1/2)0.3Ti0.44Zr0.26O3 ceramics showed the high kr of 0.67.
  • 坂本 清子, 山口 俊郎, 中平 敦
    1999 年 48 巻 6 号 p. 571-574
    発行日: 1999/06/15
    公開日: 2009/06/03
    ジャーナル フリー
    Crystalline aluminium orthophosphate AlPO4 has various polymorphic forms. However, it is difficult to prepare a pure single phase AlPO4. In order to synthesize a single phase of AlPO4, we have undertaken the dehydration of aluminium orthophosphate dihydrate AlPO4·2H2O (metavariscite) in organic solvent. The crystalline phases of obtained products were identified by X-ray diffraction method and measurement of MAS-NMR 31P and 27Al. A crystalline AlPO4 (berlinite, tridymite-form, cristobalite-form, or A-form) was selectively synthesized by controlling the amount of H3PO4 and sort of organic solvent (1-butanol and isobutyl methyl ketone).
  • 坂 志朗
    1999 年 48 巻 6 号 p. 575-584
    発行日: 1999/06/15
    公開日: 2009/06/03
    ジャーナル フリー
  • 冨野 寿和, 近藤 祥人, 東城 哲朗
    1999 年 48 巻 6 号 p. 585-591
    発行日: 1999/06/15
    公開日: 2009/06/03
    ジャーナル フリー
    The porous cast-iron bonded diamond grinding wheel showed the high grinding performance for the hard-to-grind ceramics. Hence, it is considered that the grinding performance of the said diamond grinding wheel depends on the porosity, which is the major properties for porous material.
    In this paper, to control the porosity of the porous cast-iron bonded diamond grinding wheel, we studied pulse electric current sintering behavior of atomized cast-iron-diamond composite powder. The results were as follows:
    (1) The cast-iron powder was deformed plastically at the contact between the diamond grain.
    (2) The porosity control of the atomized cast-iron-diamond composite sintered body could be performed independently of the volume fraction and the size of the diamond grain by the pulse electric current sintering method.
    (3) Both the volume fraction of diamond grain and the diamond grain size affected significantly the apparent density of the green body, because the extra pores were generated at the contacts between the atomized cast-iron powders and the diamond grains.
    (4) The densification of the atomized cast-iron powders in the composite sintered body was affected by the volume fraction of diamond grain, and was not influenced by the diamond grain size.
  • 北川 正義, 周 徳信, 島田 清典, 梅岡 秀征
    1999 年 48 巻 6 号 p. 592-597
    発行日: 1999/06/15
    公開日: 2009/06/03
    ジャーナル フリー
    Much efforts have been done to understand a constitutive equation of solid polymers. But much attention has not been paid to stress-strain behavior after un-loading. The stress-strain behavior were investigated at uniaxial and biaxial stresses for some paths with strain or stress reversal using polyethylene. The followings are interesting for studying the constitutive laws obtained from the present study: at a stress relaxation (or creep) test after unloading, the stress rate (or the strain rate) changes its sign during the test depending on the test condition (anomalous behavior after unloading; ABU), and 2) under biaxial tension creep test after unloading, only the strain in the direction along which the applied stress was unloaded showed ABU.
  • 山田 良穂, 黒部 利次, 安藤 禎憲, 堀 充宏
    1999 年 48 巻 6 号 p. 598-603
    発行日: 1999/06/15
    公開日: 2009/06/03
    ジャーナル フリー
    Stiffness reduction of poly (methyl methacrylate) (PMMA) subjected to alternating bending deformation is measured as a function of the number of loading cycle, and effects of temperature on the stiffness reduction process are investigated in the present study. Reduced method is found to be applicable between temperature and the number of loading cycle. Apparent activation energy estimated from reduced method is 23±5kcal/mol, which is comparable to that of viscoelastic β-relaxation process for PMMA. The activation energy estimated from the temperature dependence of craze density, 9±4kcal/mol is lower than that estimated on the basis of the reduced method, and this fact suggests the stiffness reduction may be attributed to the characteristics of PMMA rather than craze formation. Effects of subjecting the specimens to cyclic bending on viscoelastic properties and tensile strength are also examined.
  • 早川 弘之, 宮原 光雄, 金谷 章宏, 岡村 一男
    1999 年 48 巻 6 号 p. 604-609
    発行日: 1999/06/15
    公開日: 2009/06/03
    ジャーナル フリー
    Strain range partitioning method was applied to creep-fatigue life prediction for ligaments of high temperature boiler headers. Typical operating transient data was used to conduct thermal transient analysis and elastic-plastic-creep stress analysis with three dimensional FEM models simulating ligament parts of headers. Creep-fatigue life was predicted by strain range partitioning method based on the analytical results and creep-fatigue properties of a header material. The results obtained were as follows.
    (1) Cracking was expected in ligament parts with inelastic strain produced by thermal transient during start-up and shut-down operation.
    (2) The points where ligament crack was predicted to initiate coincided with ones reported in actual plants failure cases.
    (3) The effects of operational condition and size of header on ligament crack initiation life were evaluated by this analysis. It was found that the ligament crack initiation life tends to be shorter in the case of the faster ramp rate and the larger header diameter.
  • 西野 精一, 塩澤 和章, 小島 明弘, 瀬尾 省逸, 山本 有一
    1999 年 48 巻 6 号 p. 610-615
    発行日: 1999/06/15
    公開日: 2009/06/03
    ジャーナル フリー
    In this study, the influence of thermal aging and notch on low-cycle fatigue strength of forged mod. 9Cr-1Mo steel was investigated at elevated temperature. Total strain-controlled low-cycle fatigue tests using the smooth specimen and load-controlled low-cycle fatigue tests using the notched specimen were carried out at 873K in air. The triangular, tension-hold and compression-hold trapezoidal waveforms were applied to the specimens in a series of the tests. From the experimental results, there is no effect of the thermal aging on strain-controlled low-cycle fatigue life using the smooth specimen with each strain waveform. However, low-cycle fatigue life of the notched specimen decreased by thermal aging under load-controlled condition with triangular and tension-hold trapezoidal waveform.
  • 崔 性大, 三沢 啓志, 秋田 貢一, 児玉 昭太郎
    1999 年 48 巻 6 号 p. 616-622
    発行日: 1999/06/15
    公開日: 2009/06/03
    ジャーナル フリー
    Fatigue tests were carried out with Ti-6Al-4V alloy CT specimens after three kinds of the heat treatments, namely, 1) solution at 1223K, aging at 813K(STA), 2) annealing at 1123K(AN850) and 3) annealing at 1373K(±β-AN). X-ray fractography, which is a technique to estimate applied stress conditions when a fracture occurs and to be used for analysing a mechanism of fracture, was applied on the fatigue fractured surface. Distributions of residual stress and half-value breadth were measured on the fractured surface along the crack propagation direction as a function of a stress intensity factor. It was found that the residual stress on the fatigue fractured surface had a peak value when maximum stress intensity factor was nearly equal to 25MPa√m. The strain induced transformation was confirmed on the fatigue fractured surface from X-ray diffraction profile pattern. Depth of monotonous plastic zone size was estimated from the distribution of the residual stress beneath fractured surface. Depth of monotonous plastic zone size ωy was expressed by following equation; ωy=α(Kmaxy)2, where the values of α were 0.17 for STA and 0.13 for AN850. By using X-ray fractography technique on fatigue fractured surfaces of Ti-6Al-4V alloy, a value of maximum stress intensity factor Kmax where the residual stress reach maximum value can be predicted.
  • 中井 博, 北田 俊行, 穐山 正幸, 三田 村武, 小林 剛, 島本 明
    1999 年 48 巻 6 号 p. 623-628
    発行日: 1999/06/15
    公開日: 2009/06/03
    ジャーナル フリー
    Investigated in this paper is a new hybrid cable-wire consisting of outer new Fiber Reinforced Plastic (FRP) and a steel wire as a core. First of all, a design method of cross section of the new hybrid cable-wire is proposed on the basis of the safety factors of 1.7, 3.0 and 1.1 against the yield limit state of the core steel wire, the ultimate limit state of the hybrid wire and the hazard state corresponding to the breaking of the outer FRP by accidents from standpoint of fail safe, respectively. Next, the mechanical properties of carbon-steel hybrid wires are dealt with, which consist of outer CFRP containing parallel carbon fibers and a core steel wire, and are dimensioned by the design method and produced by a method called the pultrusion method for trial. Results of a static tensile test, bending test, lateral pressure test and fatigue test prove the possibility of their application to structural cables and the necessity of further study for developing reliable anchorage systems of hybrid cables. A corrosion test emphasizes the importance of investigation on countermeasures against galvanic corrosion of carbon-steel hybrid wires.
  • 加藤 昌彦, 張 東坤, 中佐 啓治郎
    1999 年 48 巻 6 号 p. 629-635
    発行日: 1999/06/15
    公開日: 2009/06/03
    ジャーナル フリー
    n order to analyze the cracking and delamination processes of hard coating on ductile substrate under bending load, four-point bending tests were carried out for tool steel specimens with WC-Co cermet coating. The coating was divided by cracks repeatedly with increase in the bending load, and finally the delamination of coating occurred. The interval of cracks at the same nominal stress and those at the delamination ware large when the coating thickness was large. The stress distribution in the coating was analyzed by two-dimensional elastic-plastic finite element method. In addition, the stress distribution in the coating was calculated also by an elastic-plastic stress analysis, which introduced the tensile stress in the coating σx1(x) as follows:
    σx1(x)=β{1-cosh(αpx)/cosh(αpL/2)}
    where, L is the crack interval, x is distance from the center of divided coating, and αp and β are constants which contain thickness, material's constant of coating and substrate, and nominal bending stress. The cracking process calculated both by the finite element method and the analytical method agree relatively well with the experimental results.
  • 張 東坤, 加藤 昌彦, 中佐 啓治郎
    1999 年 48 巻 6 号 p. 636-642
    発行日: 1999/06/15
    公開日: 2009/06/03
    ジャーナル フリー
    In order to evaluate the delamination strength of brittle coating on ductile substrate, the four-point bending test method was proposed by expanding the tensile test method. The delamination energy was derived as a function of bending moment, curvature of specimen at delamination of coating and material's constants by theoretical analysis where the change of strain energy both in coating and substrate at delamination were considered. The method was applied to the specimen with WC-Co coating on an annealed tool steel prepared by high-velocity flame spraying. With increasing bending moment, the coating is divided repeatedly by cracks with almost the same interval. The crack interval at the delamination increases and the delamination energy of coating decreases with an increase in coating thickness. The four-point bending method is also effective to evaluate the delamination strength of brittle coating.
  • 仁内 宏紀, 佐藤 千明, 池上 皓三
    1999 年 48 巻 6 号 p. 643-648
    発行日: 1999/06/15
    公開日: 2009/06/03
    ジャーナル フリー
    The volume variation of thermosetting resin during curing process was investigated experimentally. Typical epoxy resin of bisphenol A-epichlorohydrin cured with diamine hardener was used for specimens. The volume of the resin was measured during curing process using buoyancy in the condition of variable temperatures. Considering the results of the experiments, new theoretical procedures to predict the volume variations of thermoset resins were proposed. The prediction by the procedure showed good agreement with experimental results under various conditions of different temperature histories.
  • 高橋 寛
    1999 年 48 巻 6 号 p. 649-655
    発行日: 1999/06/15
    公開日: 2009/06/03
    ジャーナル フリー
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