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Volume 43, Issue 2
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[in Japanese]1996 Volume 43 Issue 2 Pages 150
Published: February 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSDownload PDF (80K) -
Akinori Irisawa, Shinichi Kikkawa, Fumikazu Kanamaru1996 Volume 43 Issue 2 Pages 151-156
Published: February 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSPhase relation could be elucidated between the two phases previously found out in BaPbO3 -BaCuO2 system by obtaining the single crystal product. Both phases have the molar ratio of Ba:Pb:Cu=1:0.725:0.10 and are basically isostructural to Ba4Pb3O10 which is a member of Ruddlesden-Popper series Ban+1PbnO3n+1(n=3). They can be described as Ba3.64Pb2.64Cu0.36O10_δ. The phase 2 was an oxidized form of the phase 1 with an intercalation of 0.6H2O. The phase 1 crystallized in orthorhombic Immm with a=0.430(4), b=0.429(8), c=3.026(7)nm and was a semiconductor. The phase 2 crystallized in tetragonal P4/mmm with a=0.430(5), c=1.715(2)nm and was a semimetallic conductor.View full abstractDownload PDF (1091K) -
Yoshihiro Kusano, Takeyuki Kikuchi, Jun Takada, Yasunori Ikeda, Mikio ...1996 Volume 43 Issue 2 Pages 157-161
Published: February 15, 1996
Released on J-STAGE: July 12, 2010
JOURNAL OPEN ACCESSPhases and their relations in the BaO(BaCO3)-CaO-CuO system at 900°C in air have been studied by XRD. The formation of two types of copper oxycarbonates were newly formed: one is a phase with a composition of Ba:Ca:Cu=0.600:0.080:0.320 and the other is a solid solution formed in a region of the compositional triangle of (Ba:Ca:Cu)=(0.666:0:0.333)-(0.650:0.017:0.333)-(0.650:0.070:0.280). The crystal structures of these phases have been determined by XRD, TEM and ED. These copper oxide carbonates commonly have tetragonal structures with a≈√2ap and c≈2ap. Unfortunately, no diamagnetic response was observed for the new two copper oxycarbonates.View full abstractDownload PDF (1447K) -
Takeyuki Kikuchi, Yoshihiro Kusano, Jun Takada, Yasunori Ikeda, Mikio ...1996 Volume 43 Issue 2 Pages 162-167
Published: February 15, 1996
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSPhases and their relations in the Y01.5-BaO(BaCO3)-SrO-CuO system at 900°C in air have been studied mainly by the powder X-ray diffraction method. It was found that two new phases with compositions of (Y, Ba, Sr)2CuO2(CO3)y, Bs.s, and Y:Ba:Sr:Cu = 0.5:0.7:1.0:1.0, N, formed in this system. The newly found phase Bs.s was isostructural with the oxycarbonate Sr2CuO2(C03). The phase N has an orthorombic sturucture with lattice parameters of a=3.855Å, b=3.764Å, and c=12.69Å.View full abstractDownload PDF (1612K) -
Masato Kakihana, Masahiro Yoshimura, Hiromasa Mazaki1996 Volume 43 Issue 2 Pages 168-177
Published: February 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSA novel "polymerized complex" technique has been developed to produce high-pure copper based high-Tc superconductors. The polymerized complex technique is based on the formation of a polymer resin precursor with various metal ions, which can be uniformly distributed in the polymer network keeping their initial stoichiometric ratio. The technique includes four important major steps: (1) formation of stable carboxylate complexes uniformly dispersed into ethyleneglycol, (2) fabrication of polymerized complexes which are formed through dehydration among the hydroxyl groups of ethyleneglycol and the carboxylic acid groups, (3) heating of the polymerized complex resin at moderate temperatures (around 350°C), which brings about a partial breakdown of the polymer, and (4) various heat treatments to produce a given ceramic powder. It is likely that low cation mobility in the highly viscous polymer network causes little segregation of various metal ions during the pyrolysis. It is stressed in this paper that the present technique offers more convenient and easier fabrication of high pure and homogeneous ceramic powders compared with other more elaborate preparation procedures based on wet chemical routes. Application of the polymerized complex method is demonstrated on the ceramic synthesis of polycrystalline compounds including solid solutions viz. YBa2Cu3O7-d and YBa2Cu3-xCoxO7-d. Special emphasis is placed on the outstanding purity of the product, which was examined by various techniques including X-ray diffraction, Raman scattering and complex magnetic susceptibility measurements.View full abstractDownload PDF (601K) -
Masashi Fujiwara, Takeyuki Kikuchi, Masahiro Nagae, Hideki Nakajima, J ...1996 Volume 43 Issue 2 Pages 178-182
Published: February 15, 1996
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSEffects of the Li-addition to the Bi-2212 phase on the formation process and the superconductive properties were studied for the samples with the nominal compositions of Bi:Sr:Ca:Cu:Li=2:1.5 :1.5:2:x(x=0 to 0.6). The samples were heated at 560-860°C for 1 to 48h in air. Monophasic Bi-2212 samples was obtained for x=0.2 to 0.6 by heating above 730°C, which was approximately 100°C lower than that of the sample with x=0.A new compound containing Li element was formed in the temperature range between 700 and 720°C, which remarkably promoted the formation of the Bi-2212 phase. The lattice parameter c of the Bi-2212 phase increase with increasing Li content. The temperature dependence of magnetic susceptibility showed that Tc rose up to 90K for the sample with x=0.4 heated at 750°C for 12h.View full abstractDownload PDF (317K) -
Masahiro Nagae, Jun Takada, Yoshihiro Kusano1996 Volume 43 Issue 2 Pages 183-186
Published: February 15, 1996
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSBi-2212/Ag tape samples with finely dispersed oxide(x-Al2O3 or MgO) particles were prepared by the partial melt-solidification technique. The formation and superconducting properties of the tape samples have been studied in relation to microstructure. In case of a-Al2O3 particles addition, as the oxide additive content increased, the Ic value at 77K and OT decreased remarkably because of reaction between a-Al2O3 and 2212 phase. On the other hand, MgO particles were uniformly dispersed in the Bi-2212 matrix without any reaction between 2212 phase and MgO, so that Ic almost unchanged. Isothermal magnetic hysteresis loop of MgO added samples was larger than that of non-added samples. These results suggested that MgO particle addition was effective for improvement in the flux pinning properties of the Bi-2212 phase.View full abstractDownload PDF (1513K) -
Nobuyoshi Takabatake, Etsuro Sugimata, Tatsuhiro Tachibana, Kentaro Oh ...1996 Volume 43 Issue 2 Pages 187-190
Published: February 15, 1996
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSThe electrochemical reduction was tried for Bi2.2Sr1.8CaCu208+z pellet in 0.01N AgNO3 and CuSO4 ⋅5H2O in methanol with silver and copper as the counter electrode. The resistance decreased by Ag particle deposition at the grain boundaries, and its decrease brought about the enhancement of Tco. Bi-2212 sample was reduced by Ag to about 0.24 mole fraction and by Cu to about 0.07 mole fraction. Tco was enhanced by 4K for the former and Tc(onset) was enhanced by 5K for the latter. The oxygen content of each sample was determined by ordinary iodometric titrationView full abstractDownload PDF (3894K) -
Takashi Tsubota, Wataru Muramoto, Kentaro Ohhashi1996 Volume 43 Issue 2 Pages 191-194
Published: February 15, 1996
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSWe examined the possibility of FeI2 intercalation into Bi2Sr2CaCu2Oy polycrystalline superconductor. It was found that FeI2 was not intercalated in Bi2Sr2CaCu2Oy, but IxBi2Sr2CaCu2Oy and Fe2O3 were produced by vapor phase reaction of Bi2Sr2CaCu2Oy and FeI2. Separation of diffraction lines (200), (020) for IxBi2Sr2CaCu2Oy suggest that the oxygen of Bi2Sr2CaCu2Oy reacted with Fe of FeI2. Lattice constance c for IxBi2Sr2CaCu2Oy varied from 18.3 to 18.8 with increasing x. IxBi2Sr2CaCu2Oy coexisted with Bi2Sr2CaCu2Oy between x=0.67 and 0.90. Resistance was increased and Tc was lowered by iodine intercalation.View full abstractDownload PDF (199K) -
Masato Kakihana, Minoru Osada, Susumu Katano, Hiromasa Mazaki, Hiroshi ...1996 Volume 43 Issue 2 Pages 195-199
Published: February 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSWe have investigated neutron powder diffraction of YBa2-xSrxCu3O7-d with x=0, 0.4, 0.8 and 1. Their Rietveld analyses were carried out in space group Pmmm assuming two different disordering models: Model A where the O(1) is displaced from (0, 1/2, 0) to (x, 1/2, 0) so that each alternate chain has some kind of zig-zag chain and Model B where the available oxygen atoms are located at both the O(1) and 0(5) sites to give full and empty Cu-0 chains along the a-axis. The refinements based on model B have revealed that substitution of Sr for Ba causes an increase of isotropic temperature factor for the O(1), indicating an increasing in local oxygen disordering. This disordering in the model B is consistent with the Raman results that the defect induced mode gains intensity with increasing Sr content. A possible picture of the slight decrease of Tc in YBa2-xSrxCu3O7-d is discussed in terms of both local oxygen disordering and associated charge-transfer effect.View full abstractDownload PDF (346K) -
Taketoshi Koga, Masami Mashino, Hiroshi Yasuoka, Hiromasa Mazaki1996 Volume 43 Issue 2 Pages 200-205
Published: February 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSWe measured the magnetization curve of a melt-processed YBa2Cu3Oy in the temperature region 20-60 K. Measurements were carried out by the use of a SQUID, where the applied field ranges 0-1 T. The observed curves were analyzed in the framework of the Kim-Anderson model for critical current density, where the critical current density Jc is expressed as a function of the localized flux density Bi in the sample, Jc=k/(BO+|Bi|). Here k designates the pinning force and B0 is a temperaturedependent parameter. By taking into consideration the demagnetization effect, the experimental results were reproduced very well, suggesting that the Kim-Anderson model is quite useful for the study of the magnetic response of the specimen. Some discussion on the temperature-dependent parameters involved in the model are given.View full abstractDownload PDF (305K) -
Shigeru Katsuyama, Makoto Morioka, Kazuhiko Majima, Hiroshi Nagai1996 Volume 43 Issue 2 Pages 206-210
Published: February 15, 1996
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSWe measured the normal-state Hall effect on the polycrystal of YBa2(Cu1-xMx)3Oy (M=Fe, Co) prepared by two kinds of heat treatments. The synthesized YBa2 (Cu1-xMx)3Oy (M=Fe, Co) was slowly cooled from 890°C in air. Some of them were annealed below 400°C in O2 gas (sample [O]s). The others were heated at 800°C in N2 gas followed by annealing below 400°C in O2 gas (sample [NO]s). It is considered that there is a difference in the configuration of substituent in the Cul-0 planes between [O]s and [NO]s: in [O]s the substituent is randomly located, while in [NO]s that makes clusters. The carrier density nH of [O]s and [NO]s in YBa2(Cu1-xCox)3Oy system decreases with an increase of x. In the case of YBa2(Cu1-xFex)3Oy system, nH Of [0]s decreases with an increase of x, while that of [NO]s is almost constant independent of x. The difference in the behavior of nH between YBa2(Cu1-xFex)30y and YBa2(Cu1-xCox)3Oy systems seems to be due to the difference of the microscopic structure around the substituent.View full abstractDownload PDF (268K) -
Shigeru Katsuyama, Nozomu Hashimoto, Kazuhiko Majima, Hiroshi Nagai1996 Volume 43 Issue 2 Pages 211-214
Published: February 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSYBa2Cu3Oy-Ag composite superconductor was synthesized by two kinds of methods, i.e., conventional ceramic and polymerized complex methods. There is almost no difference in the X-ray diffraction pattern between the samples prepared by the conventional ceramic and polymerized complex methods. The global pinning force Fp of the samples prepared by the polymerized complex method is larger than that of the samples prepared by the conventional method. The transport critical current density Jc of the samples prepared by the conventional ceramic method increases by the addition of Ag, while that of the samples prepared by the polymerized complex method is almost constant independent of Ag content. The values of Fp and Jc are much affected by the grain size and the distribution of Ag in the YBa2Cu3Oy matrix.View full abstractDownload PDF (252K) -
Minato Ando, Masaaki Ito1996 Volume 43 Issue 2 Pages 217-220
Published: February 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSDoping effect of TiO2, CaTiO3 and SnO2-TiO2 on the characteristics of the Aluminabased ceramics have been investigated for the application of microwave dielectric device. Conventional alumina ceramics widely used for microelectronic device had fairly large temperature coefficient of resonance frequency(τ). Doping of TiO2, CaTiO3 and SnO2-TiO2 was found to decrease τ, and 85mol%Al2O3-4.5mol%SnO2-10.5mol%TiO2 ceramics showed the lowest tanδ of 2×10-5 and τ of 21ppm°C-1 at 7GHz. It can be concluded that the low tan δ is closely related to the uniform decomposition of Al2TiO5 in the ceramics by slow cooling during firing process.View full abstractDownload PDF (240K) -
Yoshio Ukyo1996 Volume 43 Issue 2 Pages 221-225
Published: February 15, 1996
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSThe sintering reaction of sialon composite containing Y-α'-sialon and β'-sialon has been investigated in the system Si3N4-Y2O3-AlN. It is revealed that Y-α'-sialon with higher solubility is formed by the reaction between AIN and liquid phase at lower temperatures, and that Y-α '-sialon with lower solubility is formed by the reaction between Y-α'-sialon with higher solubility and the remaining Si3N4 at higher temperatures. Y2SiO5 and YAM (2Y2O3⋅Al2O3) were formed as intermediate compounds.View full abstractDownload PDF (3060K) -
Tetsuo Kato, Noriyoshi Kurata, Tomomi Yamamoto1996 Volume 43 Issue 2 Pages 226-229
Published: February 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSOn the sintered iron-12.5 chromium magnetic alloys with and without 0.1-0.2 percent mixed oxide powders composed of SiO2, CaO and Al2O3, the change of hysteresis curves in alternating magnetic field was measured to be compared with the melted alloy. It is confirmed that the magnetic properties of the sintered alloy added oxide are improved in alternating magnetic field such as maximum magnetic flux density, amplitude relative permeability and power losses in compared with the case of the no-oxide addition. And the magnetic properties of sintered alloys exceed the melted alloy in alternating magnetic field over 1kHz in spite of the inferior in direct magnetic field.View full abstractDownload PDF (336K) -
Hidemi Watanabe, Osamu Kimura1996 Volume 43 Issue 2 Pages 230-235
Published: February 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSRecent approaches to toughening of ceramics are mainly carried out by incorporation of fillers such as particles, whiskers and fillerments into ceramics matrix. In this study, three types of SiC fillers, namely, thin or thick whiskers, or rod like particle are used to fabricate composites. The diameters of fillers were 0.3, 0.7 and 2.5μm, respectively. The toughening behavior and micro-structures of these composites are examined in relation to the size effect of these fillers. Since fracture strength and fracture toughness were both measured for specimens, fracture mechanical analysis was used to determine size of critical flaws.View full abstractDownload PDF (2915K) -
Koichi Kamada, Mitsuru Nakamura, Toshihiro Yoshida1996 Volume 43 Issue 2 Pages 236-240
Published: February 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSInfluence of the addition of silicon on mechanical properties and corrosion resistances of P/M austenitic stainless steels was investigated by means of microstructual examinations, calorimetric analysis and X-ray analysis. Silicon addition to P/M austenitic stainless steels makes the sintering in the duplex structure of austenite(γ) and ferrite(α) possible by the liquid phase sintering with a eutectic liquid. For example, addition of 4mass% Si results in the formation of about 40vol% of ferrite. Tensile strength of sintered steels increases with increased silicon content, and the maximum strength (940MPa) was obtained in the steel with 4mass%Si which was sintered for 3.6ks at 1623K. On the other hand, elongation of sintered steels tends to increase with rising sintering temperature. The maximum elongation (47.5%) was obtained in the steel with 2mass%Si which was sintered for 3.6ks at 1673K. The sintered steel with 2mass%Si was found to have excellent corrosion resistance in a boiling solution of 65% HNO3 : The corrosion rate of the steel was very small in comparison with the sintered SUS304L steel, but it was three times larger than that of a SUS304L steel produced by ingot metallurgy. However, further addition of silicon causes a decline in corrosion resistance probably due to a decrease in the green density.View full abstractDownload PDF (3425K) -
Gang Han, Mitsunobu Tada, Hidenori Kuroki, Kenji Shinozaki1996 Volume 43 Issue 2 Pages 241-248
Published: February 15, 1996
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSA small amount of borax enhanced the sintering of SUS316L stainless steel powder compacts. The compacts of the -100mesh water-atomized powder with 2mass%Na2B4O7 were sintered at different temperatures in vacuum. SEM micrographs and EPMA or EDX figures of the samples indicate that the silica-based oxide film on the surface of the steel particles has dissolved into the melted flux or borax at 1070K, that Cr2B particles have precipitated from the steel matrix while silicon and manganese have concentrated into the flux following a steel/flux reaction at 1270K, and that a Fe-Cr-B eutectic liquid has been formed and the Cr2B particles have disappeared above 1470K. Sintering at 1620K for 60min resulted in the highest density of compacts with almost no vacant pores. The formation of a Fe-Cr-B eutectic liquid may have caused the enhancement of densification by the capillary-force effect of the liquid.View full abstractDownload PDF (7859K) -
Osamu Yamashita, Yoshihisa Kishimoto1996 Volume 43 Issue 2 Pages 249-255
Published: February 15, 1996
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSNd-Fe-B alloy powder was granulated by spray drying method using polyvinylalcohol (PVA) binder in the range from 0.1wt% to 0.5wt%, in order to improve the powder flowability during feeding and compacting. After adding PVA binder, glycerin and pure water to alloy powder, the slurry was stirred at 278K to suppress the oxidation of alloy powder. The granulated powders exhibited a high flowability with the increase of PVA content. By heating in H2 at 673K for 0.5H after compacting in the magnetic field, about 90% of carbon in binder was removed, although the oxygen in binder remained unremoved. With the compacted body added 0.20wt% PVA, these treatments can allow to suppress the residual contents of oxygen and carbon in the resulted sintered magnets within less than 8000ppm and 900ppm, respectively. The highest coercive force (iHc) and maximum energy product (BH) max for a sintered anisotropic magnet prepared by the above mentioned process are 1.06(MA/m) and 286.5(kJ/m3), respectively.View full abstractDownload PDF (2312K) -
Naoyuki Nomura, Kyousuke Yoshimi, Shuji Hanada, Tatsuo Tabaru, Hisamic ...1996 Volume 43 Issue 2 Pages 256-261
Published: February 15, 1996
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSIn present work, we attempt to produce rapidly solidified powder of a Nb-Al alloy by the Rotating Electrode Process(REP), and successfully obtain good powder whose scatter of aluminun concentration is relatively small. The as-REP powder has a uniformly distributed dendritic structure of the bcc phase stable at high temperatures. The powder was sintered by Hot Pressing at 50MPa and 1873K. It was confirmed by X-ray analysis and electron probe micro analysis(EPMA) that the sintered material has a fine structure consisting of Nb3Al and Nb solid solution. After heat treated at 1773K for 24h, compression tests were performed in the temperature range from 1273K to 1873K at an initial strain rate of 1.6×10-4s-1. Temperature dependence of 0.2% proof stress is found to be similar to that of previous literatures. From the results obtained, we can conclude that this process is very useful to fabricate a Nb3Al and Nb solid solution in-situ composite with a near net shape.View full abstractDownload PDF (5881K) -
1996 Volume 43 Issue 2 Pages 263
Published: 1996
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSDownload PDF (94K)
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