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Volume 39, Issue 8
Displaying 1-19 of 19 articles from this issue
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Hao-Nien Huang, Teruhisa Watanabe1992 Volume 39 Issue 8 Pages 603-607
Published: August 15, 1992
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSA model of rectangular parallelopiped skeleton having same radius straight-cylindrical pores crossing at right angles on three dimensions in itself is set up in Fig. 2-a, b, and based on it, the general equations on infiltration which were able to use for both infiltrations through one surface and through all surfaces of the skeleton were constructed. These general equations were confirmed by some experiments. The results obtained are as follows:
1) The general equation of infiltration through one surface of either lower or upper surface of the skeleton was,
V= Pr⋅S1⋅(R⋅γLV⋅COSθ/18ηL)1/2⋅t1/2
where, V: volume of the liquid infiltrated(cm3), Pr: porosity of the skeleton, S1: infiltration area of either lower or upper surface of the skeleton (cm2), γLV:surface tension of the liquid(g/sec2), R: radius of the pore(cm), θ: contact angle between the skeleton and the liquid(degree), ηL:viscosity of the liquid(g/cm'sec), t: infiltrating time (sec).
2) The general equation of infiltration through all surfaces of the skeleton was,
V=Pr⋅SA⋅(R⋅γLV⋅COSθ/18ηL)1/2⋅t1/2
where, SA:2(S1+S2+S3) [infiltration areas of all surfaces of the skeleton] (cm2).
3) According to the experiments which were carried out with the skeleton of sintered iron and the infiltrant of aqueous solution containing a surface active agent, it was found that above both equations held good at the first period of infiltration time.View full abstractDownload PDF (303K) -
Masaki Maeda, Kiichi Oda, Yasuo Shibasaki1992 Volume 39 Issue 8 Pages 608-611
Published: August 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSLithiophorite[(Al, Li)MnO2(OH)2] is the main component of natural gosu, which is produced in Seto area, and utilized as ceramic pigment. In the present work, lithiophorite containing Co ion was hydrothermally synthesized, and the extent of Co content in lithiophorite was examined. Synthetic lithiophorite was better crystallized than natural product. Synthetic lithiophorite containing Co ion consisted of platelike particles with the grain size about 0.2μm and the thickness 150-200Å. It was revealed by the energy dispersion spectroscopy that Co was substituted for Mn continuously up to about 37.8atom%[Co/(Co+Mn)]. However, the increase of Co content in the starting material resulted in the coprecipitation of spinel type by-product Co(Al, Mn, Co)2O4. In conclusion, synthetic lithiophorite containing Co ion showed well powder and coloring characteristics as ceramic pigment.View full abstractDownload PDF (1519K) -
Atsuyuki Nakano, Hiroshi Momoi, Takeshi Nomura1992 Volume 39 Issue 8 Pages 612-617
Published: August 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSEffect of Ag on the electromagnetic properties of low temperature sintered NiCuZn ferrite has been studied with special reference to the micro- and nano-structure. It is shown that As accelerates the densification of NiCuZn ferrite and promotes the dissociation of Cu from the ferrite, which causes discontinuous grain growth. Silver addition to NiCuZn ferrite brings about not only distortion of lattice near the grain boudaries but also the compression of sintered body.View full abstractDownload PDF (3283K) -
Takeshi Nomura, Yoshikazu Izumi, Yukie Nakano1992 Volume 39 Issue 8 Pages 618-623
Published: August 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSEffect of firing atmosphere on the degradation in insulation resistance of Ni-electrode multilayer ceramic capacitors under highly accelerated life test has been studied with special reference to the microstructure. The degradation behavior shows clear dependence not only on the ambient atmosphere during firing but also on the segregation of Fe- and Nn-oxides along the surface of Ni electrode. It is shown that the degradation is caused by the electrolytic migration of oxygen vacancies.View full abstractDownload PDF (4800K) -
Osami Kamigaito1992 Volume 39 Issue 8 Pages 624-629
Published: August 15, 1992
Released on J-STAGE: July 12, 2010
JOURNAL FREE ACCESSCompairing the literature values of fracture toughness of various materials revealed that the value of the same kind of material scatters largely, depending on the authors or measuring ways, but that the temperature dependence is very small and almost common, particularly in the range RT through 1, 200 °C, for most ceramics in spite of the large scattering in the absolute value. The temperature coefficient, (-(dKIc/dT)/KIc(RT)), is(-2. 1-1.6)10-5/K for SiC ceramics, and(0-1.3)10-4/K for Si3N4. The unexpectedly small temperature dependence was explained on the basis of the dependence of the surface free energy, rs.which was found to be approximated by the empirical formular (-(dγs/dT)/γso = 1/(2.1Tm) ; Tm is melting or sublimation point ) and that of Young's modulus, E. On this basis, the value of KIc at 1, 600 °C is expected not to be less than 70% of the value at RT, if the material is not affected by low heat resistant boundary material. Furthermore, the literature values are found to be 2 to 6 times larger than the ideal value calculated from (2γsE)1/2. This large value is related to the generation of rough fractured surface.View full abstractDownload PDF (313K) -
The Surface-treatment of AluminaNoboru Suzuki, Yutaka Go, Noriyuki Baba, Atsushi Endo, Hiroshi Utsugi1992 Volume 39 Issue 8 Pages 630-638
Published: August 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSAlumina puiverizea in n-nexane ana n-hexane solution of cetanol, or octaaecyltrletnoxysilane were investigated through microanalysis, dispersive property into various media, Fourier transform infrared spectroscopy (FT-IR) and pyrolysis. The followings were found; (1) The surface property of Al2O3 pulverized in n-hexane showed to be hydrophilic, exactly the same as that of those unpulverized. (2) The surface property of Al2O3 pulverized in n-hexane solution of cetanol showed to be hydrophilic, but more hydrophobic than that of those unpulverized. These properties were confirmed to be caused by their surfaces composed of alcoxy surface group and equimolar hydroxyl group. (3) The surface properties of Al2O3 pulverized in n-hexane solution of octadecyltriethoxysilane showed to be hydrophobic(lyophilic), so that not dispersive into water, but float on water like an oil. (4) The surface-treatment of Al2O3 was confirmed to be performed by formation of surface group through reaction due to surface radicals produced by their pulverization.View full abstractDownload PDF (1552K) -
Tomohiro Furukawa, Nobuya Machida, Toshihiko Shigematsu, Norihiko Naka ...1992 Volume 39 Issue 8 Pages 639-645
Published: August 15, 1992
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSUsing fine powders of YBa2Cu3Oy superconducting oxides of which particle size are about 3μm in average diameter, relations between the reaction mechanisms for oxidation and reduction, and the change in their crystal structures, which occurred within each particle, have been investigated. In a case of isothermal reduction using orthorhombic powders(oxygen content y is 6.92), it was made clear that the reaction was controlled by the removing rate of oxygen from the particle surface, so that there existed a uniform concentration of oxygen in a particle. On the other hand, in a case of isothermal oxidation of tetragonal powders(y=6.00), the reaction was recognized to be controlled by the moving rate of interface between tetragonal and orthorhombic phases, and accordingly the co-existence of two phases was confirmed by X-ray diffraction. The authors tried to analyze this oxidation-process using "Unreacted Core Model", and the activation energy of 51.3 kJ/mol was obtained. Similar experiment of isothermal oxidation was carried out upon the orthorhombic powders(y=6.44). Brief discussion was made for the experimental results obtained.View full abstractDownload PDF (370K) -
Finish CuttingEiichi Sentoku, Hironobu Kashimoto, Yoshio Fujimura1992 Volume 39 Issue 8 Pages 646-649
Published: August 15, 1992
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSIn recent years, many machinable ceramics with various kinds of properties have appeared in the market. These ceramics are used for a few mechanical and electronic parts. Machinable ceramics consisting of fluor-phlogopite can be machined with tight tolerance using conventional metal cutting equipment and tools.
The purpose of this paper is to study the shape of cutting edge for machining of ceramics with smooth finish. The lapping of the cutting edge is carried out on a newly developed lapping device. The roughness of machined surface and the tool are both improved by lapping the edge of the tool. The main results obtained are as follows : (1) The cutting edge of the insert tool is sharpened and smoothed by lapping with diamond compound. (2) The tool having the lapped edge performs the long tool life and the smooth finish of the work. (3) The flank surface in the lapped cutting edge provides a much smaller amplitude in the cutting force.View full abstractDownload PDF (1417K) -
Mitsuo Ueki, Atsushi Fukawa, Hisashi Suzuki1992 Volume 39 Issue 8 Pages 650-655
Published: August 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe fact that the nitrogen contained cermets tools show a higher chipping resistance of cutting edge would widely be accepted. However, the reason appeared not to have been clarified until now. Then, the study on this subject was undertaken in dry milling tests of TiC-(0-40) vol%TiN-10vol%Mo2C-10vol%Ni cermets tools. It was found that the deformation of cutting edge during the tests was suppressed in nitrogen contained tools with increasing nitrogen content, this leading to the decrease in the number of fine cracks forming mainly perpendicular to cutting edge. In short, the higher chipping resistance of nitrogen contained cermets tools was attributed to the superior creep strength of those cermets, being in no relation to their thermal properties, etc.View full abstractDownload PDF (6999K) -
Osamu Terada, Akira Sasaki, Hisashi Suzuki1992 Volume 39 Issue 8 Pages 656-659
Published: August 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe room temperature adhering strength of combined specimen prepared by adhesion between TiC-19mass%Mo2C-24mass%Ni cermet and WC-(10, 15)mass%Co cemented carbide was mainly studied by transverse-rupture tests. It was found that the main crack generally passed within the cermet region very neighbouring the interfacial layer formed between two sorts of alloys. It was also found that the strength increased with lowering the adhering temperatures. The reason for the above phenomena is discussed.View full abstractDownload PDF (3687K) -
Takahiro Kaneyoshi, Teruo Takahashi, Yukinobu Hayashi, Muneyki Motoyam ...1992 Volume 39 Issue 8 Pages 660-664
Published: August 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSElemental Al and Nb or Al, Nb and graphite powders were mechanically alloyed (MA) with methanol in an Ar gas atmosphere. The results of X-ray diffraction indicated that Al3Nb and NbC phases were obtained in the mixed powders mechanically alloyed longer than 72.0ks. TEM observation of MA powders revealed that nano-sized crystalline Al3Nb and NbC precipitated to make a small powder particle. The sintered compacts with high density were obtained by vacuum heating of the compacts of MA powders. Fine NbC particles dispersed uniformly in the sintered compacts and its content increased in proportion to graphite content. The hardness of the sintered compacts increased linearly with NbC content.View full abstractDownload PDF (3953K) -
Yoshiro Arami, Le Le Maw, Osamu Iwatsu, Yasuhiko Hashimoto1992 Volume 39 Issue 8 Pages 665-669
Published: August 15, 1992
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSA new electrolytic method for the production of very fine copper powder was developed and operated using a cell containing Ti3+ in 10 vol% sulfuric acid solution as an electrolyte and a copper soluble anode as the source of copper. The influences of the electrolytic conditions on the particle size and the morphology of the powder were investigated. The results obtained were summarized as follows:
1) Fine copper powder was successfully formed and precipitated at the bottom of the cell by Ti3+ -reduction of Cu2+ formed by the anodic dissolution of Cu.
2) Mean particle size of copper powder obtained was varied from 0.45 to 1.40 μm. It decreased with the decrease of Ti3 concentration in the electrolyte and with the increase of the anodic current density.
3) The particle shape changed from spherical to polyhedral as the size of the powder increased, and needle-or plate-like particles co-precipitated among the granular precipitates as the concentration ratio of (Total-Ti)/Ti3+ in the electrolyte exceeded about 10.
4) By the addition of cathodic-polarization accelerator, gelatin in particular, a reduction of particle size was observed.View full abstractDownload PDF (3922K) -
Takeshi Kaneko1992 Volume 39 Issue 8 Pages 670-674
Published: August 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThis report describes the result of investigations on the improvement of the mechanical properties of W-Ni-Fe heavy alloys produced with optimum Ni/Fe ratio and the addition of suitable amount of Co to the basic composition of W-Ni-Fe heavy alloys. The aim of this project is to improve tungsten heavy alloys, particularly with regard to their ductility and strength. Microstructural characterization and room temperature tensile testing were performed on a series of tungsten heavy alloys containing 91.3 to 97.0 wt% tungsten. For these alloys, deformation and fracture behavior were studied via slow strain rate tensile testing at room temperature.
The strength and ductility at room temperature of the heavy alloys attained a maximum with Co content of about 0.5 wt% with the Ni/Fe ratio of about 4.0. The strength maximum resulted from a trade off between volume fraction strengthening and microstructure limited ductility.
Fracture surface observation indicated that the maximum strength correlated with the tungsten cleavage failure mode. At higer tungsten contents the tendency toward intergranular failure increased.View full abstractDownload PDF (2571K) -
Akira Hara, Masaru Yokata1992 Volume 39 Issue 8 Pages 675-679
Published: August 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSIt is generally known that conventional P/M aluminum alloy parts show remarkable damping characteristics against mechanical vibrations. However, there is few internal friction (Q-1) data available to support this. Accordingly, we measured strainamplitude-dependent Q-1 of 2014 grade Al-(3-6)%Cu-0.5%Mg-0.8%Si sintered materials which were prepared from elemental mixes, at the ambient temperature by the cantilever method, with the density ratio of about constant 93%. The results are as follows: (1) In the strain-amplitude-independent part, the Q-1 measured is 7.5-8.1x10-3, which is about 10 times higher than the value of sintered iron. Moreover, after T6 treating these materials, they were found to have an even higher Q-1 than the as-sintered materials. (2) An increase in Cu content resulted in a decrease in the Q-1 of both the as-sintered and T6 treated materials. (3) Damping mechanisms appeared to be relaxations due to dislocation motion and reversible multiphase boundary sliding.View full abstractDownload PDF (1736K) -
Yoshimitsu Kankawa, Katsuyoshi Saitou, Yasunari Kaneko, Katsushi Ono, ...1992 Volume 39 Issue 8 Pages 680-684
Published: August 15, 1992
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSEffect of fatty acid lubricant to metal powder on the metal powder injection molding was studied. Stearic acid, stearamide and stearyl alcohol were used as fatty acid lubricant of the metal compounds. Both the viscosity of the SUS304L compound containing of stearic acid and that of the compound containing of stearamide were lower than that of the compound containg of stearylalcohol. However, both the viscosity of the Cu compound containing of stearic acid and that of the compound containing of stearamide were higher than that of the compound containing of stearyl alcohol. It was confirmed by IR spectra that stearic acid was transformed to copper(II) stearete in the presence of Cu powder during the kneading process.View full abstractDownload PDF (280K) -
Yoshimitsu Kankawa, Katsuyoshi Saitou, Yasunari Kaneko1992 Volume 39 Issue 8 Pages 685-686
Published: August 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe mechanism of the debinding on powder injection molding was discussed on the basis of the thermogravimetric and infrared spectroscopic analysis (TG-FTIR) data. The maximum rate of the binder weight loss increased in proportion to the heating rate in the thermal debinding process (TDP). And the paraffin wax and polybutyl-methacrylate were vaporized as thermal decomposition gas during the heating process(at 250°C for 20 min) in the TDP. On the other hand, the starting temperature of the binder weight loss in the TDP was decreased with an increase of the polyethyleneglycol removal in the solvent debinding process.View full abstractDownload PDF (295K) -
Katsushi Ono, Yasunari Kaneko, Yoshimitsu Kankawa, Katsuyoshi Saitou, ...1992 Volume 39 Issue 8 Pages 690-694
Published: August 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe recent research of Powder Injection Molding (PIM) is begining to be shifted to reducing the debinding time and keeping the shape during debinding. Though there are some methods of removing the binders, the solvent debinding which can solve the problems mentioned above becomes to get much attenion.
Here discussed the injection molding of silicon nitride powder by using both the thermal and the solvent debinding process. All the components of the binder dissolved into the solvent. This is different from the conventional AMAX process. The main results were summarized follow: l)The debinding time by using thermal and solvent debinding process could be remarkably reduced. 2)The practicabilities of removing binders and keeping the shape of green body during solvent debinding were affected by extraction conditions.View full abstractDownload PDF (1785K) -
Yukio Sasatani, Yasunari Kaneko, Yoshimitsu Kankawa, Katsuyoshi Satiou ...1992 Volume 39 Issue 8 Pages 695-700
Published: August 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThis paper presents the additional effect of the fatty acid lubricants to the compound for metal injection molding. The compound consisted of SUS304L powder and the organic binder. The organic binders used here were polystyrene, atactic polypropyrene, polybutyl-methacrylate, paraffin wax, di-n-butyl phthalate and the lubricant. The results were summarized as follows:
For the addition of palmitic acid, myristic acid or lauric acid to the compound as the lubricant, there was no difference of the effect on the mixing and flowing behavior in comparison with stearic acid. The addition of methyl stearate or stearyl alcohol was less effective on both the mixing and flowing behavior than that of stearic acid. For the addition of nickel stearate to the compound, the effect on the flowing behavior was bigger than that on the mixing behavior. In the debinding and the sintering process, there was little difference for using any kind of fatty acid lubricants.View full abstractDownload PDF (1410K) -
Nobushige Hiraishi, Tadashi Fukuda, Yoshihisa Ohashi, Junichi Kikuchi1992 Volume 39 Issue 8 Pages 701-704
Published: August 15, 1992
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSA powder metallurgy (P/M) coextrusion process for superalloy-clad steel pipes has been developed. Composite billets consisting of an Alloy625 powder layer and a wrought steel hollow billet were hot-extruded and defect-free Alloy625/2 1/4Cr-lMo steel-clad pipes were experimentally produced in commercial production facilities. The pipes were proved to have an uniform layer of cladding in longitudinal and circumferential directions. The bonding properties of the P/M-clad pipe were evaluated in shear tests, tensile tests and bend tests. Ultrasonic evaluation was carried out on the full length of the clad pipe but no defects, such as disbonding or cracking at the interface, were found. Based on the results obtained, P/M superalloy-clad steel pipes would be applicable to oil-field line pipes and chemical plant tubes.View full abstractDownload PDF (2968K)
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