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Volume 34, Issue 9
Displaying 1-36 of 36 articles from this issue
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[in Japanese]1987 Volume 34 Issue 9 Pages 368
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
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Mitsuo Kimoto, Shinro Uchida1987 Volume 34 Issue 9 Pages 369-372
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSFor the improvement of Fine Ceramics, it is necessary to be used in mechanical industry. For this industry Injection Molding Process will be applied widely in the near future. Because it is expected to have higher productivity and to form complex shapes. But Injection Molding of Fine Ceramics is not established perfectly at present. In this case, the most difficult problem is minimization of debinding time.
This report shows the result of experiment using wax binders which have less extracts at debinding process.View full abstractDownload PDF (208K) -
Nobuya Ooka, Masaaki Honda, Masaya Miyake, Kenya Motoyoshi1987 Volume 34 Issue 9 Pages 373-377
Published: November 25, 1987
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSThe method of forming thin ZrO2 bodies by Injection molding process using acrylic binder was studied. Concerning reological characteristics and properties of thermal decomposition, acrylic binder was compared with the more generally used wax binder. The flowing characteristics of the mixture of acrylic binder indicated high viscosity and gradual change in relation between temperature and viscosity. The compacts using acrylic binder had high flexural strength compared with those using wax binder. As a result, it was observed that ZrO2 mixed with acrylic binder filled the mold without defects. A mechanism for removing acrylic binder from compact which is different from that of wax binder was found. This mechanism made it possible to remove, without defects, acrylic binder, and to control the quantity of gas which decomposes the binder in the inner part of compact. Mixture with 45vol% acrylic binder was the best composition for injection moldability and removing binder. Sintered ZrO2 compact was densified by HIP (Hot Isostatic Pressing), and its mechanical properties were equal to those of the conventional process.View full abstractDownload PDF (1407K) -
Kei Miyamoto, Yuzuru Takahashi, Suguru Inamura, Hiroki Miyamoto1987 Volume 34 Issue 9 Pages 378-382
Published: November 25, 1987
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSIn the preparation of Al2O3 ceramics by the low pressure injection molding method, fine particles of raw material powder (mean particle size of 0.6μm) must be dispersed homogeneously into the organic binder in order to obtain high strength ceramics. Four different mixing methods were tested; stirrer equipped in the low pressure injection molding apparatus, automatic agate mortar, ceramic three roll mill and ball mill. It is concluded that the ball mill mixing method prepares the most uniform slurry among the four mixing methods. The specimen sintered at 1700°C for 3 hrs, after being shaped in the horizontal flow type mold from the slurry of the ball mill mixing method, shows a strength of 40.0 Kgf/mm2 and its Weibull constant is 6.9. Furthermore, the flexural strength of the sintered specimens increased from 40.0 Kgf/mm2 to 46.2 Kgf/mm2 and their Weibull constant increased from 6.9 to 14.5, as the metal mold was changed from horizontal into vertical flow type.View full abstractDownload PDF (1442K) -
Takeo Nakagawa, Nobuyuki Takahashi, Hiroyuki Noguchi, Reiko Cho1987 Volume 34 Issue 9 Pages 383-386
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSTo solve the problem that an extremely long debinding time is required before sintering in case of the ceramics powder injection molding process, the water binder is used for its easy debinding property in stead of polymer or wax binder and the shape fixing is done by freezing the binding water in the die cavity after compression forming.
The vacuum freeze drying is applied for removing the water binder in order to prevent the cracking by the shrinkage of formed powder.View full abstractDownload PDF (1378K) -
Takaaki Matsuoka, Hideroh Takahashi, Osami Kamigaito1987 Volume 34 Issue 9 Pages 387-391
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSFlow analysis has been studied in plastic injection molding. It can predict defects in the filling process with computer. The computer simulation has been used for mold design. This paper describes mold filling theory and our experience with a flow analysis program, "IMAP-F".View full abstractDownload PDF (1106K) -
[in Japanese]1987 Volume 34 Issue 9 Pages 394
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
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Nobuo Setaka, Seiichirou Matsumoto, Mutukazu Kamo1987 Volume 34 Issue 9 Pages 395-401
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe earliest substantial experimental work to grow diamond from gaseous phase at low pressure was disclosed by Eversole of UCC in 1962 and independently by Russian team of Derjaguin. Recently, the diamond film and particles with well-define habites were synthesized by Spitsyn and his co-warkers by the chemical transport process in a close system, but experimental details have not been reported.
Independently, we have shown that the growth of diamond was feasible by hot filament assisted CVD and micro-wave plasma assisted CVD process in a gas flow system.
The problems actually encountered at the diamond CVD are how to accelate thermal decomposition of hydrocarbon and how to limit the deposition of non-diamond carbon except diamond at the temperature below 1100 C. In order to satisfy these condition, it is necessary to introduce higher concentration of atomic hydrogen than equilibrium concentration related to thermal dissociation of hydrogen gas.
In this paper, our experimental work to grow the diamond from gaseous phase and also the deposition process associated with atomic hydrogen are reported.View full abstractDownload PDF (3472K) -
Kenji Kobayashi, Nobuki Mutsukura, Kiyoyuki Yamamoto, Yoshio Machi1987 Volume 34 Issue 9 Pages 402-407
Published: November 25, 1987
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSHard carbon films were prepared by r.f. plasma chemical vapor deposition (p-CVD), using hydrocarbon gases diluted with hydrogen gas. A relationship between the film properties and plasma conditions were investigated with film deposition rate, optical emission spectroscopy and electrostatic probe technique. From these results, it seems that the ionic species in the plasma should play a important role for the formation of hard carbon films. The film structures deposited on several substrates were examined by transmission electron microprobe (TEM). Almost all of the films have dominantly amorphous structure, but contain diamond particles in the amorphous phase for the films prepared only from CH4 source gas. Typical hard carbon films have a half of diamond's hardness (about 4600 kg/mm2) and a high electric resistivity (>1010Ω⋅cm).View full abstractDownload PDF (2593K) -
Mutsukazu Kamo, Yoichiro Sato, Nobuo Setaka1987 Volume 34 Issue 9 Pages 408-410
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThis paper reports a preliminarily study on the formation of diamond on commercially available carbon substrates by means of microwave (2.45 GHz) glow discharge. The features of growri diamond on carbon substrates were compared with that on silicon substrates. Diamond was formed under the following conditions: methane concentration, 0-2.5%; total pressure, 5.3 kPa; substrate temperature, 800-900°C. For identification, the deposits were studied by electron diffraction and Raman spectroscopy. The interlayer spacings of the deposits on carbon substrates are in good agreement with the values reported for diamond. A Raman peak observed at 1333 cm-1 agrees with the reported value of 1332.5 cm-1. The deposits were observed with transmission electron microscopy and scanning electron microscopy. The deposits on carbon substrates are spherical particles without truncation by substrate, which is distinctly different from those on other substrates such as silicon and molybdenum. The shape may be formed by the regression of the substrate surface with the progress of the gasification reaction of substrate with activated hydrogen. The growth features of the deposites on carbon substrates are similar to those on silicon formed under higher methane concentrations. This indicate that the hydrocarbon concentration on a carbon substrate is higher than that on a silicon substrate. Diamond also deposited from only hydrogen gas without methane on silicon substrate set by the side of a carbon substrate. That shows the chemical transport reaction of carbon from carbon substrate to silicon by activated hydrogen.View full abstractDownload PDF (2465K) -
Akihiko Ikegaya, Masaaki Tobioka1987 Volume 34 Issue 9 Pages 411-414
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe diamond layer was deposited on the cemented carbides cutting inserts by microwave plasma assisted CVD process. The microwave plasma assisted CVD equipment had precise substrate position control system and substrate cooling system. So uniform plasma was generated on the three dimensional substrate such as cutting inserts and the surface temperature of the substrate was controlled independently from the microwave input power.
The diamond coated insert at relatively high pressure and microwave input power showed good cutting performance for high speed Al-Si alloy cutting.View full abstractDownload PDF (2533K) -
Misuzu Watanabe, Kazuhiko Kawakami, Yoshiki Morikawa, Masako Tanaka, M ...1987 Volume 34 Issue 9 Pages 415-417
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSSome metals, B, P, and Al etc., introduced to a-C : H films prepared by hydrogen reactive sputtering were investigated for dopants applicable to a-C : H films from temperature dependencies of surface electrical resistivity.
Phosphorus and aluminum were appropriate for dopants since they showed reciprocal temperature dependencies of resistivity, while boron did not showed it on a-C : H deposited below 100°C.View full abstractDownload PDF (169K) -
[in Japanese]1987 Volume 34 Issue 9 Pages 420
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
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Masahiro Yoshimura1987 Volume 34 Issue 9 Pages 421-430
Published: November 25, 1987
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSThe formation and phase stability of the intermediate compounds and solid solutions in binary systems R2O3-other oxides (R=Rare earth) were reviewed and discussed from the ionic point of view: ionic scale parameter of field strength, lattice energy and site self-potentials in every sublattices.
The intermediate compounds and their phase relations were summarized in the series of systems R2O 3-WO3. Equilibrium phase diagrams for La2O3, Nd2O3 and Y2O3 were revised from previously reported ones.
In fluorite-related phases of R3TaO7, the smaller R ions led to the formation of the more disordered and higher symmetric phases.
The phase diagrams of the solid solutions in the systems ZrO2-CeO2, or-Y2O3, were also reviewed from the point of view of stable and metastable equilibria. The metastability seems to be caused by extremely slow diffusion of cation and fast diffusion of anion, and by martensitic phase transformation, in the fluorite-related phases.
The formation and stability of high-valence state of cations in the B-site of the perovskite lattice ABO3 were explained by the contribution of deep site self-potential at the B-site in this perovskite lattice.View full abstractDownload PDF (691K) -
Hiroshi Nagai1987 Volume 34 Issue 9 Pages 431-437
Published: November 25, 1987
Released on J-STAGE: July 12, 2010
JOURNAL FREE ACCESSThe effect of various rare earth elements added in various forms, i.e. metallic addition, dispersion of oxide and superficial application of oxide particles, on the high temperature oxidation resistance of Ni-Cr and Fe-Cr alloys was investigated.
Rare earth elements exhibited two excellent improving effects in reducing the oxidation rate and in suppressing the spalling of the scale. The effects of rare earth elements were much stronger than those of the other reactive elements in all additional forms.
In order to understand the mechanism by which the rare earth elements improved the oxidation resistance of the alloys, the oxygen pressure dependence of the electrical conductivity of the Cr2O3 doped with NiO and rare earths was measured. It was found that the simultaneous doping of NiO and rare earth elements changed the defect structure of Cr2O3 from p-type to n-type semiconductor at very low oxygen pressure, Po2≅10-9Pa. This result suggested that the formation of an n-type region in the scale adjacent to the alloy might act to improve the oxidation resistance by reducing the diffusion rate of cations in the scale.View full abstractDownload PDF (1658K) -
Noboru Ichinose, Koichi Motono1987 Volume 34 Issue 9 Pages 438-440
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSImprovement has been made on the thermal conductivity of aluminum nitride ceramics which is one of the hopeful candidates of substrates for semiconductor devices. The thermal conductivity has been thought to be reduced by the presence of some impurities such as oxygen and transition metal ions in the ceramics. However, much improvement was made on the thermal conductivity of aluminum nitride ceramics by using a suitable amount of yttrium oxide and calcium oxide as a sintering aid. Addition of yttrium fluoride has also brought on faily good results for improvement of its thermal conductivity.View full abstractDownload PDF (1185K) -
Masahiro Yoshimura, Yoshio Okano, Shigeyuki Somiya1987 Volume 34 Issue 9 Pages 441-444
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSIn the pseudo binary system ZrO2-YOF included in the ZrO2-YF3-YO1.5 ternary system, samples of 3.0-7.7 mol% YOF within the region of tetragonal single phase at 1300°C were isostatically hot-pressed at 1200°, 1300°and 1450°C under 200 MPa for 3 h after encapsulating into Pt capsule to avoid compositional changes. Only for ZrO2-7.7 mol%YOF, metastable tetragonal zirconia single phase was obtained as a sintered body. For the other samples (<7.7 mol% YOF) whole or most of the tetragonal phase transformed diffusionlessly to monoclinic phase during cooling.X-ray study showed that the unit cell of the tetragonal phase has larger axial ratio (c/a), and that of the monoclinic phase was more distorted (larger P) than that in the ZrO2-YO1.5 system. According to the measurement by DTA on encapsulated specimens, the tetragonal phase in the ZrO2-YOF system transformed at higher temperatures than that in the ZrO2-YO1.5 system. This seems to be caused by more distorted cells of the tetragonal and the monoclinic phases as the result of F- doping. Stress induced transformation was confirmed for the metastable tetragonal phase of this YOF doped zirconia.View full abstractDownload PDF (1461K) -
Hiroshi Yamamoto, Mitsuru Nagakura, Yoshiaki Takahashi, Ichiro Uno1987 Volume 34 Issue 9 Pages 445-449
Published: November 25, 1987
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSExperiments were carried out to investigate the effect of CaO substitution on some properties of anisotropic La ferrite magnets. It was confirmed that the substitution of CaO to La2O3 contributes to formation of the magnetoplumbite structure, and these La-Ca ferrites have excellent properties as a permanent magnet. Compositions were chosen according to the formula (La2O3)1-x(2CaO)x⋅nFe2O3, where X was varied between 0 and 1.0, and n between 12 and 6. The optimum conditions of making magnet and some properties of a typical sample are the following: chemical analysis composition La3+0.501Ca2+0.697 Fe2+0.212Fe3+11.558O19, S.S.C.: 1300°C×1 h in O2, S.C.: 1250°C×0.5h in O2, Jm=0.45T, Jr=0.43T, HCJ=170.0 kA/m, HCB=167.0 kA/m, (BH)max=35.0 kJ/m3, HA=1544kA/m, KA=3.47×105 J/m3, σs=86.6×10-6 Wb⋅m/kg, D=5.05 Mg/m3.View full abstractDownload PDF (1493K) -
[in Japanese]1987 Volume 34 Issue 9 Pages 452
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
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Tsuneo Akasi1987 Volume 34 Issue 9 Pages 453-460
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSAmong around 200 sorts of mineral containing rare-earth elements, monazite, bastonaesite, xenotime and ion absorption ore are the most valuable ones.
World reserves of rare earth minerals amount to 45 million tons of contained rare-earth oxides (REO) and China, with reserves of 36 million tons, accounts for 80% of total world reserves.
This volume would be enormous as compared with the annual consumption of around 25 thousand tons. Thus we can say that rare-earths are not "rare" today. They are one of affluent resources now.
To obtain high purity rare-earth elements on industrial scale, ion exchange and solvent extraction methods are explored.
Recently, we can obtain rare-earths at moderate prices on the ground of their intense resources develop-ment, wide application and expansion of production.View full abstractDownload PDF (2834K) -
Masato Sagawa1987 Volume 34 Issue 9 Pages 461-463
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe research of the Nd-Fe-B magnet was started from an expectation that B and/or C might expand Fe-Fe interatomic distances in rare-earth iron alloys, leading to increase the Curie temperature of them. After the success in developing the powerful Nd-Fe-B sintered magnets with record high energy products, however, a crystal structure analysis revealed that Fe-Fe pairs having small interatomic distances existed also in the Nd-Fe-B alloy. It is emphasized that the success in this work is a result of many fortunate matters which were not expected in the beginning.View full abstractDownload PDF (205K) -
Masaaki Tokunaga, Minoru Endoh, Hideki Harada1987 Volume 34 Issue 9 Pages 464-468
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe effect of 20 kinds of additional elements have been studied to increase the intrinsic coercivity for Co substituted Nd-Fe-B sintered magnets. The addition of Ga was found to increase iHc more than any other elements.
The effects of Ga addition on magnetic properties and thermal stability were investigated for Nd (Fe0.72Co0.2B0.08)5.6 and Nd0.8Dy0.2 (Fe0.86Co0.06B0.08)0.5 magnets. A combination of both Ga and Nb or Ga and W additions improved thermal stability which was attributed to the increase of iHc and good squareness by finer grains.
Typical Ga added 2 sintered magnets and their magnetic properties and exposure temperatures to keep the irreversible losses under 5% (Pc=2) were as follows.
[1] Nd(Fe0.7Co0.2B0.08Ga0.02)5.6: Br=12.2 KG, iHc=16.5 KOe and (BH)max=35.2 MGOe/140°C
[2] Nd0.8Dy0.2(Fe0.835CO0.06B0.08Nb0.015Ga0.01)5.5: Br=10.45 KG, iHc=27.1 KOe and (BH)max=26.2 MGOe/260°CView full abstractDownload PDF (286K) -
Koichiro Inomata, Tetsuhiko Mizoguchi, Akihiko Tsutai, Isao Sakai1987 Volume 34 Issue 9 Pages 469-473
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSMagnetic Properties of Nd-Fe-B based magnets with Co-Al or Co-Ga addition were investigated. Co-Al or Co-Ga addition increases Curie temperature and coercive force, hence, improves temperature coefficient of magnetic induction, and makes it possible to use the Nd-Fe-B magnets at a higher temperature. The coercive force of the magnets with Co and Ga increases with increasing B content, while it hardly changes with B content for Co and Al containing magnets. Also, the magnets with Co and Ga have a high coercive force of about 12 kOe even at low boron content of 3.5 at % which is far lower than that of Nd2Fe14B. Itwas shown that intrinsic coercive force IHc for Nd-Fe-B system magnets with various composition changes with temperature with a relation of IHc1/2∝T2/3.View full abstractDownload PDF (225K) -
Satoshi Hirosawa, Ken Makita, Hiroshi Nagata, Masato Sagawa1987 Volume 34 Issue 9 Pages 474-477
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSTemperature dependence of anisotropy field (HA) and spontaneous magnetization (Is) of Nd2Fe14B-type compounds in which Nd or Fe atoms are partially substituted by one of Dy, Co and Al is reported in connection with temperature dependence of intrinsic coercivity (HcI) of sintered Nd-Fe-B-type magnets containing the substituents at the same ratio as in the investigated compounds. Results are discussed in the light of empirical relation among HcI, HA and IS; μ0HcI=μ0HA-IS. Dy is recognized as an indispensible additive that improves the thermal stability of the magnetic properties of the Nd-Fe-B-type magnets, whereas Co, which improves temperature coefficient of remanent induction through a marked increase in the Curie temperature, has no possibility of bringing forth an increased thermal stability.View full abstractDownload PDF (230K) -
Ken Ohashi, Yoshio Tawara, Ryo Osugi, Toshikazu Yokoyama1987 Volume 34 Issue 9 Pages 478-480
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe magnetic and structural properties of R-Ti-Fe ternary alloy system were investigated. It was found that the Ti rich alloy includes a ternary compound having a ratio of R to Ti to Fe of near 1:1:10 and a tetragonal structure. SmTiFe10 compound has a high saturation magnetization and an anisotropy field with Tc of 310°C. It is a good candidate for a hard magnetic material. It was also found that Fe replacement by Co in RTiFe10 compounds increases Curie temperature and the same ternary compound exists in R-Ti-Co systems.View full abstractDownload PDF (179K) -
Shuichi Iida1987 Volume 34 Issue 9 Pages 481-484
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSAfter making a short introduction of the new frames in physics, the electronic structure and its signifi-cance in material engineering are explained in terms of the new frames in physics. The real shape of the classical orbits, an easily understandable description of the self spin-orbit coupling, and, the electronic multiplet structures of the rare earth ions are presented.View full abstractDownload PDF (291K) -
[in Japanese]1987 Volume 34 Issue 9 Pages 486
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
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Takashi Goto, Toshio Hirai1987 Volume 34 Issue 9 Pages 487-490
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe SiC-TiC in-situ composites were prepared by chemical vapor deposition using SiCl4, TiCl4, CCl4 and H2 as source gases. The deposits containing free C, TiSi2 or Ti3SiC2 were porous or granular, while the SiC-TiC in-situ composites were dense platelike. The microstructures of the SiC-TiC in-situ composites varied depending on the deposition conditions. The SiC-TiC in-situ composite prepared at Tdep=1673K, CCl4/H2=1.7x 10-2 and SiCl4/(SiCl4+TiCl4)=0.42, in which fine SiC particles were uniformly dispersed in the TiC matrix, had a high fracture toughness value (KIC) more than 10 MPam1/2.View full abstractDownload PDF (3857K) -
Kazuhiko Majima, Norihito Yamao, Keiichirou Shouji1987 Volume 34 Issue 9 Pages 491-493
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSUsing Ti-10 wt%Co binary mixed powder compact of 1.0 mm thickness as the insert material, bonding behavior of Y-PSZ was examined under the coexistence of solid and liquid by liquid phase sintering. Bonding was carried out at 1473 K for 3.6 ks under the pressure of 1-9 MPa by hot pressing, and the highest bending strength of 213 MPa was achieved in the specimen bonded under 3 MPa.
There existed the large grains in the center region of Ti-Co alloy after bonding, while near the Y-PSZ/Ti-10 wt%Co interface extremely small grains were observed. Ti and Co were observed on the fracture surface after bending test, however Zr or Y was not noticed. Therefore the interfacial strength between Y-PSZ and Ti-Co alloy is assumed to be much higher. A newly built layer, about 0.3 μmm thick, was also recognized along the interface between Y-PSZ and Ti-Co alloy.View full abstractDownload PDF (2576K) -
Shoji Noda, Haruo Doi, Osami Kamigaito, Noritomo Suzuki, Tomomi Ishigu ...1987 Volume 34 Issue 9 Pages 494-496
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe interface of the Zr/sapphire implanted with N+ ions were examined by RBS and cross-sectional TEM observations. The ion implantation induced the interdiffusion of atoms at the interface and the clear border-line between the Zr film and sapphire was found to disappear. The thickness of the diffusion layer was estimated to be about 10 nm at the interface of the Zr/sapphire implanted with N+ ions to the dose of 2×1017/cm2.View full abstractDownload PDF (1284K) -
Asa Kimura, Fukuji Suzuki1987 Volume 34 Issue 9 Pages 497-501
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSColored nacreous pigment used so far is a mixture of various colored pigments and titanium dioxide coated mica (TiO2-coated mica). One of the major problems for apprications to cosmetics and other fields is the lack of stability and safety of it. We have developed a colored nacreous pigment having bright color tone and pearly gloss having excellent stability and safety. In order to obtain such colored nacreous pigment, a part of titanium dioxide layer on mica was reduced to black titanium oxide, and then the reduced TiO2-coated mica was coated with titanium dioxide. The products obtained were the colored nacreous pigment, which was colored by interference color of titanium dioxide, and had extremely improved color tone, good consistency of color appearance and interference color. Various colors were available by adjusting the thickness of the titanium dioxide layer coated on the reduced TiO2-coated mica. This colored nacreous pigment does not contain any colored pigments.View full abstractDownload PDF (2335K) -
Masao Takahashi, Suguru Inamura, Kohji Nobugai, Fumikazu Kanamaru1987 Volume 34 Issue 9 Pages 502-506
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSA change of band gap for Ti1-xAlxN solid solution was discussed by means of their crystal structures and electronic structures. In the wurtzite phase an indirect transition contributes to the UV absorption process, in contrast to AlN which is known to a direct band gap material. It is found from the XPS analysis that electrons on Ti metal play an important role on energy band for the solid solution. The relation between the band gap change and Auger parameter is also discussed.View full abstractDownload PDF (385K) -
Masaru Masuyama, Junichi Funayama, Nobutatsu Yamaoka1987 Volume 34 Issue 9 Pages 507-514
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSMFC based on SrTiO3 or (Sr, Ca)TiO3 ceramics were developed as a noise and surge absorption element. They have both characteristics of varistor and capacitor. They showed the excellent electrical characteristics such as ε s.app; (6-40)×104, a; 10-20, the current surge absorption capabilities; 3000A/cm2 and so on. The semiconductive ceramic grains and the grain boundaries of a SrTiO3 ceramic with a BL structure were much effective on these electrical characteristics. So, these electrical characteristics were obtained by controlling the BL structure of (Sr, Ca)TiO3 base ceramics. The grain sizes of SrTiO3 ceramics were controlled between 10μm and 150 μm.
In addition, The increase of the leakage currency through a MFC was unobserved after supplying several high surge impulses, while that of a ZnO ceramic varistor was much more in the same condition.
When MFC was applied on a power transformer circurt and a fast rise-up impulse noise were supplied to the cercuit, it has been comfirmed that the induced noise level observed on a secondary transformer circuit can be depressed to lower level. In consequent, MFC is available to prevent electrical equipments from being damaged by a noise or a high surge energy.View full abstractDownload PDF (1464K) -
Makoto Kuwabara, Misao Mutoh, Yasutake Hara, Hidetsugu Nakamura1987 Volume 34 Issue 9 Pages 515-517
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSJoining of a metallic conducting BaPbO3 ceramic with a semiconducting TiO2 ceramic has been made at 1000°C in air, with the aim to form ferroelectric BaTiO3 or PbTiO3 layers at the interface between the two ceramics by solid state reaction.
The formation of BaTiO3 and PbTiO3 double layers at the reaction interface between the two ceramics joined was confirmed by XMA and X-ray diffractometry, but no ferroelectric behavior in the dielectric properties of the joined body of the two ceramics has been observed in the present experiment.View full abstractDownload PDF (1083K) -
Osamu Kimura1987 Volume 34 Issue 9 Pages 518-521
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSIt is well known that large thermal stresses arise in a ceramic-metal joint with thermal expansion mismatch. Therefore, to avoid fracture of a joint, it has been recommended a "compressive joint" in which thermal expansion coefficient of a ceramic is smaller than that of a metal.
A finite element calculation (F.E.C.), however, showed that a large tensile stress occurred even in a ceramic part of a compressive joint. We have already dealt with a special joint in which the values of the elastic constants of the ceramic are the same as those of the metal. The result of the calculation are found in qualitative agreement with F.E.C. In this paper, another stress analysis is carried out for a usual joint with different elastic constants, to obtain quantitative agreement with F.E.C.View full abstractDownload PDF (221K) -
Yuji Katsumura, Keiichi Kobori, Hisashi Suzuki1987 Volume 34 Issue 9 Pages 522-527
Published: November 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe Al2O3 based ceramics having 25 vol% single addition of different carbides were prepared by hotpressing and their resistance to oxidation in air mainly at 1573-1773 K was intensively investigated. The ceramics containing SiC in powder or whisker form were found to have the highest resistance to oxidation among many ceramics prepared with a single addition of different carbides. It was revealed out that the scale of the above ceramics, containing mullite phases, had a very tight structure with few micro-pores. Discussion as for the reason why Al2O3-SiC system shows such a superior oxidation resistance has been given.View full abstractDownload PDF (6530K)
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