巻号一覧
59 巻, 10 号
選択された号の論文の14件中1～14を表示しています
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沼田 英夫, 富塚 功, 辻本 得蔵1995 年 59 巻 10 号 p. 997-1005
発行日: 1995年
公開日: 2008/04/04
ジャーナル フリーEffect of cathodic polarization (CP) times on the polarization curves was studied for TiAl-base alloy in 2.5 kmol/m3 H2SO4 at 293 K. CP was carried out at −900 mV vs SCE for 10 min or 130 min. Effects of CP time on change of anodic current density (Ia) versus holding time at −530 mV and 0 mV were also studied. The results were compared with those of pure Ti and Al. The anodic reaction product was examined by XRD, EDX, SEM and hydrogen (H) analysis.
The cathodic current density (Ic) and Ia of the alloy increased with the CP time, while those of pure Ti and Al were not affected by the CP time. The decrease of Ia with time of the alloy at 0 mV did not obey the parabolic rate law in contrast with Ti. Ia of Ti did not change with time at −530 mV but Ia of the alloy decreased. It is considered that H was absorbed in the alloy during CP and enhanced the cathodic and the anodic reactions, which result in preferential dissolution of Al and concentration of Ti and H in the alloy during anodic polarization (AP). The electrochemical characteristics of the alloy were induced not by degradation of the passive film but by absorption of H during CP.
XRD revealed the formation of two kinds of hydrides with a tetragonal and a hexagonal structure on the reaction surface of the alloy after 130 min CP. The hydrides were not observed after 10 min CP, but they were formed by AP after the CP. An electrochemically affected layer was formed on the alloy surface, which is 10 μm thick and enriched by H.抄録全体を表示PDF形式でダウンロード (1231K) -
高山 善匡, 杜澤 達美, 加藤 一, 後田 祐一1995 年 59 巻 10 号 p. 1006-1012
発行日: 1995年
公開日: 2008/04/04
ジャーナル フリーAbnormal grain growth in three dimensions has been simulated using a fcc lattice with a Monte Carlo technique. The technique is fundamentally the same one as had been employed successfully by Exxon group to model grain growth, recrystallization and so on. The microstructural evolution, the grain volume distribution and the geometrical features of grain have been studied in stereology or quantitative metallography. The growth of abnormally large grains is modelled appropriately in three dimension, which is reflected distinctly as the change in volume frequency of the grain size distribution. The standard deviation for the grain volume distribution, lnσgV increases and the mean number of faces per grain, \barFg decreases during abnormal grain growth. It is understood that the decrease of \barFg is attributed to the larger decrement in the number of faces for neighbors than the increment for the abnormally-growing grain. In addition, the simulated results for the grain volume distribution and the relationship between the grain volume and the number of faces per grain are in good agreement with the experimental ones on normal grain growth.抄録全体を表示PDF形式でダウンロード (588K) -
門前 亮一, 飛田 雅史, 北川 和夫1995 年 59 巻 10 号 p. 1013-1017
発行日: 1995年
公開日: 2008/04/04
ジャーナル フリーThe effects of segregation of alloying elements (P, Bi and Ag) on the boundary-dependent capability of grain-boundary sliding of various [011] symmetric tilt boundaries in Cu have been investigated below 573 K from experiments using an electron microscope technique. The technique utilizes the sliding-induced rotation of moiré fringes on boundary BCC Fe-Co particles in an aged Cu-Fe-Co alloy and is capable of detecting sliding of less than 1 nm. The viscosity of a boundary increases and then reaches a saturation stage as the amount of segregation of each element increases. At the saturation stage, the activation energies Q for sliding are in agreement with those Qv for the bulk diffusion of the elements in Cu. For boundaries which have values of Q larger than Qv before adding the elements, the boundary viscosity is not affected by the segregation of the elements. These experimental results can be explained qualitatively from the viewpoint of grain-boundary diffusion.抄録全体を表示PDF形式でダウンロード (551K) -
篠崎 信也, 高橋 芳朗, 向井 楠宏1995 年 59 巻 10 号 p. 1018-1023
発行日: 1995年
公開日: 2008/04/04
ジャーナル フリーIn order to obtain fundamental information for clarifying the reason why spinel-alumina refractory has strong resistance against slag corrosion, interfacial reactions between Al2O3-MgO substrate and liquid iron were investigated by the use of X-ray diffractometer and X-ray micro analyzer.
When the substrate contains non-stoichiometric MgAl2O4 spinel and the oxygen content of iron is sufficient, iron diffuses easily with oxygen into the substrate, which leads to the formation of (Fe, Mg)Al2O4 spinels in the vicinity of substrate-liquid iron interface. The formation of (Fe, Mg)Al2O4 spinels containing a large amount of iron occures when α-alumina coexists with MgAl2O4 spinel in the substrate. (Fe, Mg)Al2O4 spinels have larger lattice constants than MgAl2O4 spinel. Decrease in porosity of substrate after the reaction can be interpreted to be caused by the formation of (Fe, Mg)Al2O4 spinels.
It is speculated from the estimated activity coefficients of FeO in (Fe, Mg)Al2O4 spinels that non-stoichiometric MgAl2O4 spinel enriched by Al2O3 has a prominent ability to trap FeO.抄録全体を表示PDF形式でダウンロード (611K) -
川又 勇司, 清水 得夫, 四條 好雄1995 年 59 巻 10 号 p. 1024-1029
発行日: 1995年
公開日: 2008/04/04
ジャーナル フリーThe separation and determination of trace amounts of Bi and Sb in high-purity Sn were studied. After the sample was dissolved with mixture of phosphoric acid and sulfuric acid, Bi and Sb were separated from Sn by extracting into xylene with diethylammonium diethyldithiocarbamate (DDDC) and subsequently back-extracted into nitric acid for the determination by ICP-AES. Sn are little extracted from phosphoric acid solution, so it is possible to separate Bi and Sb from Sn. The apparent distribution ratios (D) of Bi, Sb and Sn between 5×10−2 mol/l DDDC-xylene and 4 mol/l phosphoric acid-0.5 mol/l sulfuric acid were found to be 1.7×103 for Bi, 2.5×103 for Sb and 5.5×10−3 for Sn. Therefore, the separation factors (S=DM⁄DSn) of Bi and Sb from Sn are calculated to be 105 level, respectively. The recoveries of Bi and Sb were satisfactory throughout the extraction with 5×10−2 mol/l DDDC in xylene from 4 mol/l phosphoric acid-0.5 mol/l sulfuric acid solution and the back-extraction with 60% nitric acid. Y was used as an internal standard for ICP-AES measurements. The diverse elements which are contained in Sn caused no interference for the determination of Bi and Sb. The detection limits were found to be 41 ng/g for Bi and 84 ng/g for Sb using 1 g of Sn sample. The proposed method was applied to analysis of the real samples and a reference material with good results.抄録全体を表示PDF形式でダウンロード (575K) -
横山 誠二, 斎藤 己由, 伊藤 直人, 川上 正博1995 年 59 巻 10 号 p. 1030-1035
発行日: 1995年
公開日: 2008/04/04
ジャーナル フリーMolten iron was evaporated in cold gas stream of argon+oxygen mixture in order to investigate the influence of vapor condensation in a reactive gas on evaporation rate. Iron was levitation-melted in argon+oxygen (PO2=0.0∼0.6 kPa) flows at a given temperature (2173∼2273 K) keeping total gas flow rate of 1.67×10−4 m3·s−1 (STP).
The evaporation rate was discussed with using the counter diffusion model of iron vapor and oxygen within gaseous boundary layer. Oxygen diffused beyond the site where iron vapor nucleated in argon. The oxygen reacted with the iron vapor in the boundary layer. The boundary layer thickness for iron vapor decreased with an increase of the oxygen partial pressure, so that the evaporation rate in argon+oxygen was larger than that in argon and increased linearly with the oxygen partial pressure. When the oxygen partial pressure exceeded a certain value, the evaporation rate became constant regardless with the oxygen partial pressure because the boundary layer thickness was unvaried with the oxygen partial pressure.
In this experiment, ultra fine particles were prepared due to rapid cooling of vapor and condensed particles. The condensed particles obtained in argon were α-Fe, on the other hand the particles in argon+oxygen were Fe3O4. The mean diameter of Fe3O4 was ca. 57 nm and it was unchanged with oxygen partial pressure and temperature. Although variance of particle size disribution of Fe3O4 was unaffected with oxygen partial pressure, it increased with temperature.抄録全体を表示PDF形式でダウンロード (944K) -
佐藤 芳幸, 原 基, 品田 豊1995 年 59 巻 10 号 p. 1036-1040
発行日: 1995年
公開日: 2008/04/04
ジャーナル フリーHigh temperature oxidation behavior of Cr was examined under a N2-50%O2 atmosphere including 1%HCl by volume. At 973-1073 K, mass gains of Cr in the atmosphere were larger than those in 100%O2. Temperature dependence of the mass gain of Cr after oxidation in an 1%HCl atmosphere was very peculiar. At the temperatures lower than 1073 K, the mass gains in 1%HCl increased with a rise in oxidation temperature. But at higher temperatures than 1123 K, the mass gains were relatively small and became close to the values in 100%O2. In addition, temperature dependence of corrosion loss of the specimen in 1%HCl was almost the same as that of mass gain in 1%HCl. It was also found by XRD and EDX analyses that scales formed on Cr in 1%HCl consisted of Cr2O3 containing some chromium chloride. These oxidation behaviors of Cr in 1%HCl were investigated thermodynamically, and it was proposed that the mechanism of the accelerated oxidation induced by HCl was explained by chlorination reaction of Cr and oxidation reaction of chromium chlorides inside the scale.抄録全体を表示PDF形式でダウンロード (626K) -
湯瀬 栄一郎, 松田 光明, 大塚 一雄, 品田 豊1995 年 59 巻 10 号 p. 1041-1046
発行日: 1995年
公開日: 2008/04/04
ジャーナル フリーThis paper describes the influence of some reaction factors on the particle size control for the production of Ni-P amorphous particles, especially the concentration of the reducing agent and the temperature of the reaction system. Reagents used in this experiment were as follows; NiCl2·6H2O as a nickel origin, NaOH as a pH regulator, and NaPH2O2·H2O as a reducing agent and also as a phosphorous origin. The metallic salt solution was composed of a solution of the reducing agent and a pH regulator mixed in the fixed proportion. After completion of the reaction, produced precipitates were analyzed with SEM, TG-DTA, XRD and EPMA. Except for the high concentration of the reducing agent and the high reaction temperature, spherical particles were obtained. The higher the reaction temperature and the concentration of the reducing agent, the smaller became the average particle diameter measured from the SEM images. The smallest average particle diameter was 0.1 μm, and the largest one was 2.5 μm. According to the thermal analysis curves and the XRD patterns, almost all the particles were recognized as amorphous. The chemical composition of the powders confirmed by EPMA was mainly nickel and phosphorus.抄録全体を表示PDF形式でダウンロード (534K) -
並川 靖生, 江上 雅裕, 塩原 融1995 年 59 巻 10 号 p. 1047-1054
発行日: 1995年
公開日: 2008/04/04
ジャーナル フリーThe melt convection phenomena in YBa2Cu3O7−x (YBCO) single crystal growth by the modified pulling method (Solute Rich Liquid-Crystal Pulling method; SRL-CP method) have been investigated by using a numerical calculation. The finite difference method was used to calculate the steady state of the axisymmetric 2-dimensional incompressible viscous fluid system. In order to clarify the property of the melt convection, the dimensional analysis was performed with changing various parameters for the calculation, such as the crystal rotation rate, the melt viscosity, etc. The intensity ratio of the forced to the natural convection in the melt could be expressed by Re1.5Dsc0.7/Gr, where Re, Gr and Dsc were the Renolds number, the Grashof number and the diameter ratio of the crystal to the crucible, respectively. And also, the dimensionless crystal growth interface temperature, Θ could be expressed by Θ=C Re0.028Pr0.041Gr0.019Dsc0.064, where Pr was the Prandtl number and C was a constant. These results agreed well with the experimental results, and indicated that in this system, the heat transport was mainly dominated by the forced convection.
On the basis of these calculated results, the YBCO single crystal which was 14.5mm×14.5mm×13mm could be grown along the c-axis by the pulling method.抄録全体を表示PDF形式でダウンロード (1375K) -
江 莞, 李 敬鋒, 川崎 亮, 渡辺 龍三1995 年 59 巻 10 号 p. 1055-1060
発行日: 1995年
公開日: 2008/04/04
ジャーナル フリーThe high-temperature deformation and fracture behavior of molybdenum/partially stabilized zirconia composites prepared by powder metallurgical route, was evaluated up to 1573 K by means of modified small punch test (MSP), which had been originally designed for the evaluation of brittle to ductile transition in metallic materials used for nuclear applications. For the design of thermal barrier type of functionally graded materials, along with the thermomechanical properties in full compositional range, a special attention must be paid for evaluating the transition behavior of deformation and fracture with temperatures because of definite contribution of inelasticity of materials under thermal loading to the failure often observed during cooling. The results of the dependence of MSP load-deflection curve on temperature have shown apparent transitions in the deformation and fracture of the composites: that is, every composite, which is brittle at room temperature, turns into ductile above a certain critical temperature and shows the similar load-deflection curve to those obtained in the case of ductile metallic materials. The brittle to ductile transition temperature which corresponds to the critical temperature was determined accurately by analyzing the temperature dependence of MSP-energy which was figured out as the area below each load-deflection curve. It has been found that the transition temperature is susceptible to the sintered microstructure, where the variation in transition temperature can be more closely related to the continuity of constituent phases rather than the nominal composition. The brittle to ductile transition behavior has been shown to be dependent not only on the temperature but also on the composition, which was quantitatively represented in an MSP-energy transition map.抄録全体を表示PDF形式でダウンロード (918K) -
岡崎 義光, 許 健司, 伊藤 喜昌, 立石 哲也1995 年 59 巻 10 号 p. 1061-1069
発行日: 1995年
公開日: 2008/04/04
ジャーナル フリーThe corrosion resistances of Ti-15%Zr-4%Nb-4%Ta-0.2%Pd-0.2%O-0.05%N and Ti-15%Sn-4%Nb-2%Ta-0.2%Pd-0.2%O alloys were compared with pure Ti grade 2, Ti-6%Al-4%V ELI (Extra low interstitial), Ti-6%Al-2%Nb-1%Ta and β type Ti-15%Mo-5%Zr-3%Al alloys for medical implants by anodic polarization and immersion tests at 310 K in various pseudo saline solutions.
The change in current density was small up to passivity zones in 1% lactic acid, PBS(−), calf serum and eagle’s MEM+bovine serum solutions except 5%HCl. The current density change of Ti-15%Zr-4%Nb-4%Ta-0.2%Pd-0.2%O-0.05%N alloy was lowest among the whole Ti alloys. Current density at higher voltage region more than 2 volt tend to be higher in the following relation; Ti-6%Al-4%V ELI>Pure Ti grade 2>Ti-6%Al-2%Nb-1%Ta>Ti-15%Sn-4%Nb-2%Ta-0.2%Pd-0.2%O>Ti-15%Zr-4%Nb-4%Ta-0.2%Pd-0.2%O-0.05%N alloy in α+β type alloys. Otherwise the passive current density of the β type Ti-15%Mo-5%Zr-3%Al alloy was higher than that of α+β type alloys. Passive films formed on Ti-15%Mo-5%Zr-3%Al alloy in the calf serum consisted mainly of TiO2, ZrO2, Al2O3 and Mo as demonstrated by X-ray photoelectron spectroscopy (XPS).
The rate of Ti ion released from Ti alloys in a deaerated 5%HCl solution decreased with increasing Zr, Nb, Ta, and Pd contents. Especially, the rate of Ti ion released from Ti-15%Zr-4%Nb-(2∼4%)Ta-Pd alloys containing Pd in the range from 0 to 0.2% decreased remarkably compared to 0.2 to 0.5%Pd. The passive films formed on the Ti-Zr-Nb-Ta-Pd and Ti-Sn-Nb-Ta-Pd alloys containing 0.2%Pd in the immersion test consist mainly of TiO2, ZrO2, SnO2, Sn, Nb2O5, Ta2O5 and Pd or PdO. The rate of released Ti increased by the following relation; Ti-15%Sn-4%Nb-2%Ta-0.2%Pd-0.2%O≥Ti-6%Al-2%Nb-1%Ta≥Ti-6%Al-4%V ELI≥Pure Ti grade 2>Ti-15%Zr-4%Nb-4%Ta-0.2%Pd-0.2%O-0.05%N≥β type Ti-15%Mo-5%Zr-3%Al alloy.抄録全体を表示PDF形式でダウンロード (1076K) -
岡崎 義光, 許 健司, 伊藤 喜昌, 立石 哲也1995 年 59 巻 10 号 p. 1070-1077
発行日: 1995年
公開日: 2008/04/04
ジャーナル フリーTi-15 mass%Zr-4%Nb-4%Ta-0.2%Pd-0.2%O-0.05%N and Ti-15%Sn-4%Nb-2%Ta-0.2%Pd-0.2%O alloys without V and Al elements for surgical implantation were cast by vacuum arc-melting in response to recent concerns about the long term safety of Ti-6%Al-4%V extra low interstitial alloy (ASTM standard for surgical implantation). After the alloys were forged in their α and α+β regions, specimens of 30 mm in diameter and 13 mm in height were arc-melted in an argon gas atmosphere with a titanium casting machine for dental use using a tungsten electrode. The molten alloys were cast into a graphite mold by centrifugal force. The cast microstructures of the Ti-Zr and Ti-Sn alloys consisted of α′ martensitic structure. To examine the centrifugal alloy properties for dental application, the corrosion resistance and mechanical properties of the alloys were investigated by the anodic polarization in 5 mass%HCl and 1 mass% lactic acid solutions, the measurement micro-Vickers hardness and the tensile test at room temperature. The anodic polarization properties of the Ti-Zr and Ti-Sn alloys cast in a 1% lactic acid solution are almost the same as those of Ti-Zr and Ti-Sn alloys annealed at 973 K for 7.2 ks after α+β forging. A rapid increase in current density resulted from the low potential in a 5%HCl solution in comparison with the annealed Ti-Zr and Ti-Sn alloys. The passive films on the Ti-15%Zr-4%Nb-2%Ta-0.2%Pd and the Ti-15%Sn-4%Nb-2%Ta-0.2%Pd alloys in a 1% lactic acid solution consisted of TiO2, ZrO2, SnO2, Nb2O5, Ta2O5 and PdO or Pd as demonstrated by X-ray photoelectron spectroscopy (XPS). Micro-Vickers hardness dose not change from the surface to the central part in castings. The strength of the cast Ti-Zr and Ti-Sn alloys was higher than the annealed Ti-Zr and Ti-Sn alloys. However, the ductility of the cast alloys was lower than the annealed ones.抄録全体を表示PDF形式でダウンロード (1192K) -
岡崎 義光, 許 健司, 伊藤 喜昌, 立石 哲也1995 年 59 巻 10 号 p. 1078-1083
発行日: 1995年
公開日: 2008/04/04
ジャーナル フリーThe corrosion fatigue and mechanical properties of Ti-15%Zr-4%Nb-4%Ta-0.2%Pd-0.2%O-0.05%N and Ti-15%Sn-4%Nb-2%Ta-0.2%Pd-0.2%O alloys were compared with those of Ti-6%Al-4%V ELI, Ti-6%Al-2%Nb-1%Ta and β type Ti-15%Mo-5%Zr-3%Al alloys for medical implants by corrosion fatigue testing in a physiological saline solution at 310 K and tensile testing at room temperature. The corrosion fatigue test was carried out under the condition of a tension to tension mode with a sine wave at a stress ratio of 0.1 and at a frequency of 10 Hz in eagle’s MEM+bovine serum solution using an environment cell with 90%N2+5%CO2+5%O2 gas bubbling.
The titanium alloys annealed at 973 K for 7.2 ks showed an acicular structure containing 15 to 30 vol% elongated β grains. The effect of alloying elements on ultimate tensile strength could be estimated by the following equation.
(This article is not displayable. Please see full text pdf.)
\ oindentThe cycle to failure of Ti-15%Sn-4%Nb-2%Ta-0.2%Pd-0.2%O and Ti-15%Zr-4%Nb-4%Ta-0.2%Pd-0.2%O-0.05%N alloys annealed at 973 K for 7.2 ks increased linearly with decreasing applied maximum stress. The fatigue strength at 107 cycles in those alloys was about 650 MPa. The fatigue strength at 107 cycles in Ti-6%Al-2%Nb-1%Ta alloy was about 750 MPa, and it was higher than that of Ti-6%Al-4%V ELI alloy, i.e. 690 MPa. The fatigue strength of 107 cycles in the β type Ti-15%Mo-5%Zr-3%Al alloy was lower than that of the α+β type alloys. Dimple and striation formed by corrosion fatigue testing were seen in the fractured surface of the α+β type alloys, while a river pattern was seen in fatigue surface of the β type alloy.抄録全体を表示PDF形式でダウンロード (1360K) -
盛田 芳雄, 蒲生 孝治1995 年 59 巻 10 号 p. 1084-1085
発行日: 1995年
公開日: 2008/04/04
ジャーナル フリーPDF形式でダウンロード (239K)
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