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Volume 39, Issue 3
Displaying 1-17 of 17 articles from this issue
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Tsutomu Yamamoto1992 Volume 39 Issue 3 Pages 163-167
Published: March 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe residual stresses of coated layer and WC phase of substrate for cemented carbides coated with TiC or TIN by CVD process and PVD process were measured by X-ray stress measuring method. It was mainly discussed from a standpoint of surface residual stress that the CVD-coated carbide was inferior in the failure resistance compared with the PVD-coated carbide or the uncoated carbide.View full abstractDownload PDF (1490K) -
Koji Tanoue, Yoshinori Ohtani, Koji Fujii, Hidehiko Matasuda1992 Volume 39 Issue 3 Pages 168-173
Published: March 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe creep behavior of powder metallurgy tungsten wires is analyzed at high temperatures using the θ-projection method based on the exhaustion theory of active dislocations. The parameters taken in the method are well characteristic of some properties during creep such as grain boundary sliding on which the heating rate and the bubble effect may have a great influence. It is possible to get a creep curve at an arbitrary set of temperature and stress using the parameters.View full abstractDownload PDF (1568K) -
Yuichi Iwase, Tomoaki Koga, Nichihiko Nagumo1992 Volume 39 Issue 3 Pages 174-178
Published: March 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSMixtures of Si3N4, and Ti were milled with a high energy ball mill under argon atmosphere and successively sintered with a hot press. The resulted reaction products were fine mixtures of Ii5 Si3, TiSi2, IN and Si, their fractions varying according to initial compositions, milling time and sintering temperatures. The temperatures at which sintering proceeded was much lower than that for sintering of Si3N4, again depending upon compositions and milling time. The density of sintered products was high enough with hardness comparable to that of TiN. Sound indentations without cracking were noted.A model based on kinematical rather than thermodynamical equilibrium aspect was presented to explain the dependence of reaction products on process parameters.View full abstractDownload PDF (1465K) -
Kazuhiro Yamaguchi, Yoshihiro Kusano, Minoru Fukuhara, Akira Doi1992 Volume 39 Issue 3 Pages 179-183
Published: March 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe coloration of Hidasuki on Bizen-yaki is due to the formation of hematite. When a mixture of Bizen-clay and potassium chloride was heated at above 1150t, glassy phase was formed. Hematite was formed during the cooling process of the glassy phase. In this study the behavior of hematite in the heating and the cooling processes of biotite and in those processes of a mixture of biotite and potassium chloride were studied. Biotite which contains iron ions in its structure is found in a parent rock of Bizen-clay. When biotite was heated at 5001, its basal spacing decreased to form dehydrated phase I followed by gradual decrease of the basal spacing up to 1000°C. When biotite was heated at 1000°C, dehydrated phase 0 was formed and hematite appeared coincidentally. When mixtures of 8wt% of potassium chloride and biotite were heated, hematite was found at above 500°C and the basal spacing decrease in biotite was also found at 500°C. Hydrogen chloride was detected at above 570°C. Leucite was formed at 1100°C and glassy phase appeared at 1300°C. Part of the hematite dissolved in the glassy phase. When the glassy phase was cooled down slowly, hematite was recrystallized.View full abstractDownload PDF (274K) -
[in Japanese]1992 Volume 39 Issue 3 Pages 186
Published: March 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSDownload PDF (92K) -
Tetsuya Kameyama, Kenzo Fukuda1992 Volume 39 Issue 3 Pages 187-191
Published: March 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSUltrafine carbide powders of Fe-Si-C and WC1-x were prepared utilizing a new radiofrequency thermal plasma system and their chemical properties were examined.
Ultrafine Fe-Si-C powders were prepared in the plasma from the reactant gases of SiH4-CH4-Fe(CO)5. Phases of powders were classified to two groups; one is composed of β-FeSi2, which was very active for the selective formation of olefin in the Fischer-Tropsch reaction, the other is of α-Fe, Fe3Si and Fe5Si3, which gave high CO conversion. Ultrafine WC1-x powder in the phase of 90-95 wt% with the particle diameter of 5-20nm was obtained from the reactant gases in the mole ratio of CH4/WO3 with over than 15. It was stable thermally below 1, 000°C under Ar atmosphere but it began to decompose to W2C over 1, 000°C. Ultrafine WC1-x powder promoted catalytically the formation of n-butane in the hydrogenation of cis-2-butene.View full abstractDownload PDF (233K) -
Kazuhiro Majima, Soichi Yagyu, Shigeru Katsuyama, Hiroshi Nagai1992 Volume 39 Issue 3 Pages 192-196
Published: March 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSMechanical alloying (MA) in NH3 has been applied to prepare Fe4N powder or Fe16N2 powder, where the two different kinds of iron powder, i.e., electrolytic iron powder and carbonyl iron powder, were used as the starting materials. N and O both in electrolytic iron powder and carbonyl iron powder were detected to increase in accordance with the time-length of MA. For example, after 160 hours of MA there were 12 at% N and 2 at% 0 in the specimen of electrolytic iron powder, and 11.5 at% N and 2.7 at% 0 in the specimen of carbonyl iron powder. In addition, H in the above mentioned electrolytic iron powder was confirmed to be very small amount of 17 ppm. Neither Fe4N nor Fe16N2 were found to exist in the two kinds of mechanically alloyed specimens. However, after annealing treatment, Fe4N was observed in the both specimens, while Fe16N2 was not.View full abstractDownload PDF (4240K) -
Kazuhiro Majima, Norikazu Niimi, Shigeru Katsuyama, Hiroyuki Tomizawa, ...1992 Volume 39 Issue 3 Pages 197-201
Published: March 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSMechanical grinding(MG) in Ar and mechanical alloying(MA) in NH3 have been applied to prepare Sm2Fe17Nx permanent magnet, where the three diffrent kinds of alloy powders, i.e., Sm2Fe17, Sm2Fe17C and Sm2Fe17C2 were used as the starting materials. Though Sm2Fe17 and Sm2Fe17C specimens obtained by MG or MA were recognized to consist of α-Fe and Sm-Fe amorphous phase, Sm2Fe17C2 specimen obtained by MG or MA process was confirmed to consist of only Sm-Fe amorphous phase. The fine grain particles under a single domain size( ?? 260nm) were obtained both by MG and MA, where the powder obtained by MA in NH3 was finer than that obtained by MG in Ar. Nitrogen content of the powder obtained by MA in NH3, increased as MA time passed. On the contrary, hydrogen content once increased at the first stage of MA, and after that decreased with the increase of MA time.View full abstractDownload PDF (1301K) -
Toshimasa Morooka, Eiji Yuasa, Osamu Matsumoto1992 Volume 39 Issue 3 Pages 202-205
Published: March 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSMixtures of copper, titanium and boron powders were mechanically alloyed for various periods of the milling by using an attritor ball mill. Microstructural changes of mechanically alloyed powders through the processing were investigated. Structure consisting of extremely fine grain is formed in either case of the mixed powders by the processing for long milling time. The refinement of Cu-Ti powder is accelerated by additions of boron and TiB2 powders. Solubility of titanium in copper phase of powder is about 2mol% after the mechanical alloying for more than 72.0ks, regardless of content of titanium. Intermetallic compound TiB2 is formed in the Cu-Ti-B system by the solid state reaction of titanium and boron during the processing for long milling time.View full abstractDownload PDF (4403K) -
Sennosuke Takahashi, Katsuya Kudaka, Yoshio Uozu, Kiyokata Iizumi1992 Volume 39 Issue 3 Pages 206-210
Published: March 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSBy using the stirrer-type ball mill which is used for mechanical alloying, nickel rich Ni-Mo-Cr-Co metal powders added with titanium carbide powder were mixed and pulverized in wet condition for a total time of 120 hours. With increase in processing time, the shapes and sizes of the powder particles tended to be uniform and the contents of nickel, titanium, molybdenum, carbon and cobalt were decreased but the contents of chromium and iron were increas-ed. Especially the content of iron which was not added to the starting mixed powders increased up to a few percents.
The hot-pressed specimens of the powders mixed in wet and dry condition were compared in their hardness and microstructure. In the former, fin titanium carbide particles were dispersed in nickel alloy matrix whereas in the latter, titanium carbide particles which have high hardness were extinguished to alloy with nickel and then the hardness of the latter decreased to be about 1/5 that of the former.View full abstractDownload PDF (4377K) -
Hisashi Kuwano, Yoshikazu Hamaguchi1992 Volume 39 Issue 3 Pages 211-215
Published: March 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSMo powders were mechanically ground in a carbon steel, a stainless steel and a tungsten carbide vial with several sample to ball weight ratios yielding the nano-size crystallites.The time dependences of the grain size, the compositional change and the distortion accompanied by the ball milling were investigated for the ball-milled powders. Nano-size Mo alloys with an average diameter of 6nm were obtained by the ball milling, regardless of the kind of the vial material. Large compositional changes of Fe, Fe+Cr+Ni and W content were involved by the grain size refinement after the long time milling in the carbon steel, the stainless steel and the tungsten carbide vial, respectively. The decrease of the weight ratio of sample to ball was effective for the preparation of a specified grain sized powders within the decreased milling time, though it was accompanied by a large distortion.View full abstractDownload PDF (251K) -
Hisashi Kuwano, Yoshikazu Hamaguchi1992 Volume 39 Issue 3 Pages 216-220
Published: March 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSPowders of an Fe-50%V alloy were mechanically milled by steel balls in a steel vial under an Ar atmosphere. The mechanical attrition yielded nano-size crystallites with an average grain size of 9 nm after the 180h milling. The grain size decreased exponentially with milling time, accompanied by a rapid increase in the Fe content in Mo by 40%Fe. Mossbauer effect measurements suggest that the Fe atoms mixed from the milling vial and ball are nearly randomly distributed in the powders. The refinement of the grain size under 20 nm resulted in a decrease of the ferromagnetic Fe in amount, which led to an increase in the nearly paramagnetic Fe components at room temperature.View full abstractDownload PDF (256K) -
Satoru Ohno, Chun-Sheng Jiang, Hideo Okuyama, Kazuhiro Honma1992 Volume 39 Issue 3 Pages 221-226
Published: March 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe composite ultrafine particle (UFP) of Ni and TiC was synthesized by arc melting, vaporization and deposition of Ni-Ti-C alloys in an atmosphere of hydrogen-argon mixed gas ("reactive plasma-metal" reaction) at 0.1MPa pressure. The crystal structure, the chemical composition, the morphology and sintering characteristics of obtained UFP were determined by X-ray diffractometry, energy dispersion analysis for X-ray, transmission electron microscopy and dilatometry, respectively.
The UFP obtained from Ni-Ti-C parent alloys containing 60-90 mol%TiC was composed of three phases of Ni, TiC (NaCl type) and Ni3Ti. The TiC concentration of the UFP remarkably deviated negatively from TiC concentration of the parent alloys. The composite UFP consisting of Ni and TiC, whose morphology was dumbbell-like, dice-like or ball-like particles, was found in the obtaind UFP. It is considered that those composite particles are formed during the solidification process of a molten Ni-Ti-C particle condensed in the gas-phase. Dilatometric measurements under hydrogen atmosphere show that the composite UFP has different sintering characteristics from mixed powders of Ni UFP and TiC UFP.View full abstractDownload PDF (2687K) -
Sakiko Taenaka, Hiroshi Nagai, Kazuhiko Majima, Shigeru Katsuyama1992 Volume 39 Issue 3 Pages 227-230
Published: March 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSCobalt magnetic fluid was prepared by vacuum evaporation method. The colloidal fluid obtained was heated up to 150, 200, 250 and 280°C for 20min in Ar atmosphere. The effects of concentration of surfactant and heat treatment temperature on particle size and its distribution were studied by torsion magnetometer and TEM. As a result, the particle size was controlled by varying the relative concentration of the particles to surfactant and heat treatment temperature. It was difficult to redisperse the cobalt particles flocculation. so it is suggested to use the oil substrate with the high concentration of surfactant. The saturation magnetization of the fluid was improved by heat treatment.View full abstractDownload PDF (2574K) -
Susumu Kasukabe1992 Volume 39 Issue 3 Pages 231-234
Published: March 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSUltrafine particles less than lum in diameter show a characteristic property originating from the size effect. For their effective industrial applications, ultrafine particles of a single crystal. having active crystallographic planes were produced by gas-evaporation technique.
Ultrafine particles of Ag and Pd were formed by controlling their particle size and crystal habit. The experiments of the sintering of these Ag particles showed a drastic lowering of a melting point: the sintering temperature of Ag of 30-150nm was 150-210°C. The smaller the particle size became, the lower the sintering temperature was obtained. When these ultrafine particles were applied for the conventional process of Ag and/or Ag-Pd thick film, the low resistivity of the film were obtained by forming a dense film. These experimental results are due to the effect of the surface activity of a ultrafine particle.View full abstractDownload PDF (4718K) -
Masaru Yokota, Masaaki Naka1992 Volume 39 Issue 3 Pages 235-238
Published: March 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSFor obtaining monodispersed Ti02 particles, precipitaion from homogeneous solution (PFHS) method using urea as precipitant was applied at 343K for the formation of titanium hydroxide particles containing sulfate radical from aqueous solution of titanyl sulfate and urea. In the present study, influence of ultrasonic vibration on precipitation reaction was also discussed from the results of TG-DTA analysis, X-ray diffraction, SEM images and particle distribution analysis.
As-prepared precipitates were amorphous particles, and crystalized completely on heating process up to about 1300K with dissociating hydrate and sulfate radical to anatase type Ti02 powder at about 900K and to rutile type Ti02 at about 1400K. Particle size and degree of monodispersion of Ti02 obtained by adding ultrasonic vibration on reaction was smaller and more proceeded than those obtained by conventional precipitation reaction.View full abstractDownload PDF (2408K) -
Microstructure of Hydroxyapatite-Hematite Composite Particles Prepared by Ultrasonic Spray PyrolysisAkiyoshi Osaka, Akira Chiba, Tatsuo Fujii, Tokuro Nanba, Jun Takada, Y ...1992 Volume 39 Issue 3 Pages 239-242
Published: March 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSAqueous solutions of calcium nitrate stabilized with EDTA, ammonium dihydrogen orthophosphate and iron (III) nitrate were mixed before they were subject to ultrasonic spraying and to subsequent pyrolysis in an electric furnace, and particles of 0.45μm in average diameter consisting of hydroxyapatite and hematite were obtained. Surface morphology and microstructure of the particles were examined. A nucleus (hematite)-shell (hydroxyapatite) type structure was observed for larger particles (>0.8μm in diameter) though the particles of medium size apparently had a uniform microstructure. Such structural difference due to the particle size was explained in terms of decomposition of the Ca-EDTA chelating bond at lowest temperatures and temperature distribution in the sprayed mists.View full abstractDownload PDF (2384K)
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