巻号一覧
43 巻, 7 号
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林 國郎1996 年 43 巻 7 号 p. 828
発行日: 1996/07/15
公開日: 2009/05/22
ジャーナル フリーPDF形式でダウンロード (84K) -
Hideshi Miura, Tadatoshi Honda1996 年 43 巻 7 号 p. 829-839
発行日: 1996/07/15
公開日: 2009/05/22
ジャーナル フリーThis study with metal injection molding considers the combined influences of powder characteristics and subsequent debinding and sintering conditions on the control of carbon content and microstructure for many types of high performance ferrous materials. Carbon retention and sintered structure vary significantly with the powder characteristics. Although carbon retention is sensitive to the debinding and sintering atmosphere and conditions, the carbon content can be successfully controlled by adjusting the weight loss after debinding. Mechanical properties are also investigated and compared with that of conventional P/M and wrought materials, and some factors affecting the properties are discussed taking the structure into account. Finally, high performance properties depend on two types of microstructure, one is the fine homogeneous structure in the case of high alloy steels and the other is the fine heterogeneous structure in the case of low alloy steels.抄録全体を表示PDF形式でダウンロード (9852K) -
Yoshimitsu Kankawa, Mutsumi Atarashi, Yoshinori Akifusa, Yasunari Kane ...1996 年 43 巻 7 号 p. 840-845
発行日: 1996/07/15
公開日: 2009/05/22
ジャーナル フリーVarious kinds of organic polymers were studied for the optimum organic binders on metal injection molding. Polyacetal(POM) is a degradation type polymer, and the rate of degradation is faster than that of other polymers. However, POM is eluted from the mixture of polyolefin polymers (polyethylene and polypropylene) and paraffin wax in the molten state. During thermal debinding process, the brown parts made of the feedstocks containing POM had cracks at high debinding speed, but the brown parts made of the feedstocks containing polyacetal polyethylene polymer-alloy polymer (POM/PE) had no cracks and no pores . During thermal debinding process, the degree of distortion of the test pieces with the feedstocks containing POM/PE was smaller than that of the test pieces with the feedstocks containing polyolefin polymer . The carbon content of sintered parts was less than 100ppm, and the relative density of sintered parts was 96%.抄録全体を表示PDF形式でダウンロード (3460K) -
Mutsumi Atarashi, Yoshimitsu Kankawa, Tatsuaki Nakano, Yasunari Kaneko1996 年 43 巻 7 号 p. 846-851
発行日: 1996/07/15
公開日: 2009/05/22
ジャーナル フリーThe applicability of powder injection molding technology to the molding of meso carbon micro beads was studied. The green bodies produced by injection molding of meso carbon micro beads were sintered after thermal debinding in oxidizing (air) and nonoxidizing (N2) atmospheres. For the sintered body debound thermally in a nonoxidizing atmosphere, the density and bending strength were 1.433 Mg/m3 and 20.25MPa, respectively. For the sintered body debound thermally in an oxidizing atmosphere, they were 1.304Mg/m3 and 2.39MPa, respectively. When the green bodies produced by injection molding of meso carbon micro beads were debound thermally in air, carbon powder contained in the green bodies was oxidized. Because of this, the sintered body which debound thermally in an oxidizing atmosphere exhibited low density and bending strength as compared to those of the sintered body which debound thermally in a nonoxidizing atmosphere. When a polyamide was used in the fabrication of meso carbon micro beads, the sintered density and bending strength were 1.770Mg/m3 and 42.62MPa, respectively.抄録全体を表示PDF形式でダウンロード (2856K) -
廣瀬 徳豊, 寒川 喜光, 浅見 淳一1996 年 43 巻 7 号 p. 852-857
発行日: 1996/07/15
公開日: 2009/05/22
ジャーナル フリーIn order to study the effect of heating on the dewaxed specimens which were metal injection molded varying injection speed and pressure, the structure were observed by an acoustic microscope and a scattering electron microscope, and also the transverse rupture strength was investigated.
According to the acoustic images and back scattering electron images of metal injection molded specimens which were heated over the melting point of polymer and cooled down to room temperature, there were obviously differences between the structures of green and dewaxed specimens. The polymer, which existed around metal powders before melt, flowed into the powder-powder interfaces at over melting point, and then solidified at the powder-powder interfaces and connected the powders at room temperature. Transverse rupture strength of the specimens heated at near the melting point of polymer increased with an increase in heating temperature. The strength of specimen heated at 503K for 300s were approximately six times higher than that of the dewaxed specimens. The flash of specimens heated at over melting point of polymer and cooled down to room temperature was removed easier and the fracture surfaces were smoother than those of dewaxed specimens.抄録全体を表示PDF形式でダウンロード (6821K) -
三浦 秀士, 米津 麻里, 中井 真澄, 川上 雄士1996 年 43 巻 7 号 p. 858-862
発行日: 1996/07/15
公開日: 2009/05/22
ジャーナル フリーFor miniaturization and complication of the shape of electronic devices in recent years, both high magnetic and mechanical properties are also being required to the soft magnetic components. A metal injection molding(MIM) process has the attributes of forming the high density, complex shaped and high performance components, which seems to be a suitables process for fabricating the higher performance soft magnetic components.
In this paper, the effect of MIM process conditions on the magnetic and mechanical properties of soft magnetic materials such as Fe-Ni and Fe-Si alloys were investigated. Although the final density was obtained approximately 96% of theoretical in both steels, the magnetic properties were similar or inferior to that of the pure iron. Especially, the coercive force was increased with an addition of alloying elements, because the orientation of domain walls were prevented from the grain refining and the residual oxides. Generally, taking account of the improvement in the mechanical properties which are superior to that of the conventional P/M materials, it will be able to apply a MIM process to the soft magnetic components.抄録全体を表示PDF形式でダウンロード (4293K) -
馬場 剛治, 山西 祐司, 本田 忠敏, 三浦 秀士1996 年 43 巻 7 号 p. 863-867
発行日: 1996/07/15
公開日: 2009/05/22
ジャーナル フリーIt is well-known that the high performance sintered alloys were obtained by a Metal Injection Molding (MIM) process. Although assessment of the dynamic properties such as fatigue strength is important to design a reliable structural sintered steels, especially for the high strength steels, there are very few reports about the dynamic properties of MIM steels at the present time. In this study, the behavior of fatigue properties for high strength 4600 steels (Fe-1.8%Ni-0.5%Mo-0.2%Mn) produced by the MIM process using mixed elemental powders were investigated taking the microstructure into account.
Sintered and heat treated steels showed the fine heterogeneous microstructures with the segregation of Niadded as one of the alloying elements. The fatigue strength of heat treated MIM 4600 steels were higher than that of the conventional P/M steels because of the near full-densification and the spheroidization of pores. Additionally, the regions of a high nickel concentration, which were hard martensite or retained austenite and were uniformly distributed within the tempered martensitic matrix, were also effective against the crack propagation. This result indicated that it is possible to attain high performance structural steels combined with high static and dynamic strength by MIM techniques.抄録全体を表示PDF形式でダウンロード (7823K) -
佐野 三郎, 伴野 巧, 小田 喜一, 芝崎 靖雄1996 年 43 巻 7 号 p. 868-872
発行日: 1996/07/15
公開日: 2009/12/04
ジャーナル フリーTo fabricate a green body with uniform density, the pressure controlled slip casting of low-soda alumina was carried out using a porous resin mold. By the constant pressure slip casting, the rate of cake buildup decreased with time. The rate of cake buildup became constant by the linear increasing of slip casting pressure with time. Abrupt change of density near mold surface was observed in the constant pressure slip tasted body, but the green body with uniform density was obtained by the slip casting controlling the pressure increased linearly with time. These results are supported from the analytical results of the filtration theory.抄録全体を表示PDF形式でダウンロード (288K) -
武田 義信, 明智 清明, 藤原 敏男1996 年 43 巻 7 号 p. 873-878
発行日: 1996/07/15
公開日: 2009/05/22
ジャーナル フリーRapidly solidified powder metallurgical aluminum alloys for automobile and home appliance industries were developed. Rapid solidification made it possible to refine microstructures and to expand the range of alloy composition. Al-Si-TM(Transition Metal) alloys have higher strength, higher Young's modulus, lower CTE(Coefficient of Thermal Expansion) and better machinability than those of conventinal aluminum alloys.
The powder was consolidated into NNS(Near Net Shape) either by CIP-hot extrusion or by compact-hot forging process. The new extrusion process eliminates expensive encapsulating and scalping processes, hot pressing and/or hot forging. The new direct powder forging process gets rid of surface layer on particles which blocks sintering. The parts made of the alloys have been commercially manufactured and used as key components of air conditioners and motorcyle engines.抄録全体を表示PDF形式でダウンロード (3829K) -
藤井 忠行, 上平 一茂, 本多 均一1996 年 43 巻 7 号 p. 879-884
発行日: 1996/07/15
公開日: 2009/05/22
ジャーナル フリーThe growth kinetics of secondary recrystallized grains with specific orientations in the 90% hot rolled molybdenum sheets doped with CaO and MgO were investigated. Specific grains which are developed exclusively during secondary recrystallization in straight-and cross-rolled sheets have two kinds of orientaions with near {112}<111> and {335}<556>, and near {123}<121> and {126}<10, 81> respectively. The activation energies for the growth of secondary recrystallized grains with specific orientations were estimated to be 69-78 kcal/mol in the temperature range 1900-2200°C. The temperature dependence of the grain growth rate G was described by G=3.0×104 exp (-73000/RT) cm sec-1 for the {112}<111> orientation and G=5.4×103 exp (-70000/RT)cm sec-1 for the {123}<121> orientation. Moreover, the growth rates of secondary recrystallized grain are closely related to the crystallographic orientation relation between secondary and primary recrystallized grains, and the size of grains obtained for primary recrystallized sheets as results of rolling procedures.抄録全体を表示PDF形式でダウンロード (2684K) -
塩野 剛司, 福家 章利1996 年 43 巻 7 号 p. 885-889
発行日: 1996/07/15
公開日: 2009/12/04
ジャーナル フリーIn order to study the applicability of a slip-casting technique to preparation of ceramic composites consisting of powders with different specific gravity, the technique was applied to ZrO2-WC system. During casting process, ZrO2 and WC were afraid to separate due to the difference in their specific gravity, that is, 6.07 for ZrO2 and 15.6 for WC.. For preparing fluidal and thick slurry, the optimum amounts of water and dispersant were determined on the basis of the viscosity and the density of green compacts. The optimum amounts of water and dispersant were 60vol% and 0.35mass%, respectively. The dispersibility was estimated by an EDX analysis and SEM observation. WC powders were found to disperse uniformly in ZrO2 matrix, when the thick slurry consisting of raw powders was cast. The prepared compacts were sintered at a temperature from 1400°C to 1700°C. The density and mechanical properties of composites were improved with an increase in sintering temperature. The bending strength and fracture toughness of the composites sintered at 1700°C were 820MPa and 7.4MPa⋅m1/2, respectively. The improvement of the boundary between ZrO2 and WC was guessed to make their properties enhanced further.抄録全体を表示PDF形式でダウンロード (2403K) -
寺下 敬次郎, 宮南 啓1996 年 43 巻 7 号 p. 890-895
発行日: 1996/07/15
公開日: 2009/05/22
ジャーナル フリーCompacted manganese dioxide-graphite is used for the positive electrodes of coin-shaped lithium cells. The surface roughness of such compacts was examined and measured using a laser microscope. The examined compacts were produced with variations in pre-compact and compact pressures. The hardness of each compact was also measured. These examinations and measurements yielded the following:
1) Laser microscopic examination permits quantitative and microscopic evaluation of the surface roughness of each compact. A 3-dimensional representation of the examined results offered a more detailed image of surface roughness (profile).
2) A pre-compact pressure of no more than 20% of the compact pressure, enabled the production of a molding with a considerably smooth surface and little textural variation.
3) A compact pressure of 294 to 392MPa is sufficient to produce the compacts with a smooth surface and revealed the sufficient hardness as not to break when handled.抄録全体を表示PDF形式でダウンロード (3880K) -
山口 修, 廣田 健, 稲村 偉1996 年 43 巻 7 号 p. 899-906
発行日: 1996/07/15
公開日: 2009/12/04
ジャーナル フリーSpecial attention has been given to partially stabilized ZrO2 (PSZ), tetragonal ZrO2 polycrystal (TZP), and ZrO2-toughened Al2O3 (ZTA) to improve the fracture toughness (KIC) and bending strength (σb) of ceramics. In a recent study, it was shown that in the system ZrO2-Al2O3, ZrO2 solid solutions (ss) are formed metastably up to ≈40 mol% Al2O3 from amorphous materials prepared by the alkoxy-method. Isostatically hot-pressed ZrO2(ss) ceramics exhibit very high KIC (23 MPa⋅m1/2) and plastic deformation at room temperature, although their σb is weak (≤700 MPa). The texture consists of a homogeneous microstructure with a grain size of ≈50nm. To improve ab, two kinds of ceramics have been fabricated by the addition of a small amount of Y2O3: (1) perfect ZrO2(ss) ceramics and (2) composite ceramics of ZrO2(ss) and a-Al2O3. Composites with a homogeneous dispersed cc-Al2O3 result in a remarkable increase of σb (1445 MPa). The ratio of ZrO2(ss) and α-Al2O3 can be controlled by the amount of Y2O3 addition and sintering temperature. A new method for preparing solid solutions from chlorides using hydrazine monohydrate has been developed in some systems. This paper describes the mechanical properties of PSZ, TZP and ZTA ceramics fabricated using ZrO2(ss) powders prepared by some sol-gel techniques.抄録全体を表示PDF形式でダウンロード (6436K) -
液滴の放出と二次粒子の発生熊谷 良平, 吉武 雅美, 日高 謙介, 時實 正治1996 年 43 巻 7 号 p. 907-912
発行日: 1996/07/15
公開日: 2009/05/22
ジャーナル フリーThe study on the ejection process of the droplets from the edge of the molten surface during plasma rotating electrode process (PREP) of the titanium electrode was carried out under the condition in which an appropriate deviation between the plasma center and the rotating electrode center was applied.The experimental results suggest that the retaining force which principally consists of surface tension of the liquid phase and act to the each droplets, is affected by the local shape of the molten surface of the electrode where ejection of the droplet occures. At the lower plasma voltage, relatively sharp edge of the electrode was formed, and then the produced particle diameter was smaller than that obtained under the ordinary operation voltage. Such a result may be caused by formation of protuberances overlaped on the edge of the electrode. Further PREP experiments were carried out using the special electrodes whose surfaces were surrounded by the lines of protuberances. The results informed that existance of such protuberances introduce a posibility of obtaining the smaller particles and the decreased secondary particles.抄録全体を表示PDF形式でダウンロード (4765K) -
星加 哲志, 平岡 裕, 兪 明基, 崔 〓1996 年 43 巻 7 号 p. 913-917
発行日: 1996/07/15
公開日: 2009/05/22
ジャーナル フリーMolybdenum alloy wire doped with La2O3 of 0.2% by mass was heated in hydrogen atmosphere at temperature between 1123 and 2473K, and subjected to three-point bend tests at temperature from liquid nitrogen temperature to room temperature. Then fracture surface of the specimen failed at liquid nitrogen temperature was examined by using a scanning electron microscope and crack initiation and propagation sites were determined. Finally relationship between fracture strength and ductility at low temperatures and grain stracture was discussed. In the present study the low-temperature fracture strength and ductility were represented by two parameters, critical stress and critical temperature, respectively.
Results are summarized as follows.
1) For the specimen mainly composed of fibrous structure;
Critical stress decreased substantially and in contrast critical temperature increased slightly with the increase of heating temperature. Crack initiation site was the boundary transversing the fiber and then the crack propagated across the fibrous structure.
2) For the specimen mainly composed of large and elongated grain structure;
Critical stress was almost unchanged but critical temperature decreased though only slightly, with the increase of heating temperature. The crack initiation site was the boundary of a relatively small and equiaxed grain and then the crack propagated across the large and elongated grains.抄録全体を表示PDF形式でダウンロード (4125K) -
水沼 晋, 友清 寿雅, 三牧 敏太郎, 藤井 秀樹, 直井 久1996 年 43 巻 7 号 p. 918-923
発行日: 1996/07/15
公開日: 2009/05/22
ジャーナル フリーIn the process of production of Ti-6Al-4V alloy, which consists of blending of extra-low-chlorine T i and 60mass%Al-40mass%V master alloy, cold compaction, vacuum sintering and hot forging, the influence of compaction stress and sintering conditions on the density of sintered compacts and various forging characteristics of the sintered compacts were investigated.
The increasing rate of the compact density during heating up to sintering temperature depends on density of the green compact and heating time, with which it has a linear correlation. The increasing rate of the compact density during holding at sintering temperature is in proportion to the power of the holding time. The empirical equation of the density change during sintering was derived from these findings, and confirmed to coincide well with experimental values.
The density after forging is strongly influenced by pressure and plastic deformation during forging. Tile holes in the compact can be rejected completely by suitable forging condition, except the surface area of the compact where the temperature reduces rapidly compared with that of the inner part of the compact.抄録全体を表示PDF形式でダウンロード (4462K) -
水沼 晋, 友清 寿雅, 三牧 敏太郎, 藤井 秀樹, 直井 久1996 年 43 巻 7 号 p. 924-929
発行日: 1996/07/15
公開日: 2009/05/22
ジャーナル フリーThe high temperature deformation characteristics of sintered Ti-6Al-4V alloy were investigated using specimens produced by the process of blending of extra-low-chlorine Ti and 60mass%Al-40mass%V master alloy powders, CIP and vacuum sintering. Hot compression tests were carried out using Formaster test machine at the temperatures ranging from 1123 to 1323K and at the strain rates from 1×10-3 to5.8×101s-1.
Cracks are formed more easily in the specimens with lower relative density and at the higher reduction ratio. At the temperatures in the single β phase region, the crack formation becomes more easy at the higher strain rates. On the other hand, higher strain rates rather suppress crack formation at the temperatures in the α+β two phase region. The flow stress, deformation temperature and strain rate can be correlated with Zenner-Hollomon parameter, and the activation energy for deformation is higher than the previously reported value which was obtained using wrought material. Hot deformation converts the coarse microstructures in the as-sintered specimens to refined ones, which are believed to exhibit excellent mechanical properties.抄録全体を表示PDF形式でダウンロード (1781K) -
Shigetoshi Muranaka1996 年 43 巻 7 号 p. 930-933
発行日: 1996/07/15
公開日: 2009/05/22
ジャーナル フリーIndium oxide films were reactively deposited on the indium oxide substrates at room temperature. The influence of the substrate on the film structure and the physical properties was studied. The structure of the films was greatly dependent of the freshness of the substrate surface. On the fresh substrates, crystallized films could be deposited, while films were almost amorphous on the air-exposed substrates. The disordered structure of the films was ascribed to contamination of the substrate surface with water vapor. The electrical and optical properties of the films were also described.抄録全体を表示PDF形式でダウンロード (1658K) -
藤原 幸男, 小宮山 孝, 竹村 輝男, 滝野 貢一, 谷井 良和1996 年 43 巻 7 号 p. 934-939
発行日: 1996/07/15
公開日: 2009/05/22
ジャーナル フリーA method for the preparation of the powder of tantalum capacitor was investigated. The fine grinding of tantalum powder with binder in a dry phase was conducted in the particle composition equipment.
The effect of grinding time on the particle size distribution, angle of repose, tap density and the frequency response of impedance of the powder in the particle composition equipment was investigated.
It was found that the DC resistance of the conducted powder is closely related to the angle of repose and tap density.抄録全体を表示PDF形式でダウンロード (376K) -
石本 史雄, 山本 憲司, 高橋 渉1996 年 43 巻 7 号 p. 940-945
発行日: 1996/07/15
公開日: 2009/05/22
ジャーナル フリーRadially oriented Nd-Fe-B ring magnet can be used as rotor magnets of AC Servomotors and outer magnet of small DC motors. In the manufacturing process of this ring magnet, cracking of the axial direction in the internal surface of the ring is found to take place with the large probability after sintering and Argon-cooling process. Though it is estimated that this cracking is caused by the circumferential stress of the internal surface which exceeds the mechanical strength of the Nd-Fe-B magnet material, it is very important to understand process conditions which cause the internal cracking quantitatively because of the establishment of the manufacturing process of the ring. Then, after the mechanical properties and the various thermal constants of Nd-Fe-B material were measured, cracking behavior of this rings has been investigated using a FEM method.抄録全体を表示PDF形式でダウンロード (4253K)
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