巻号一覧
67 巻, 6 号
選択された号の論文の12件中1～12を表示しています
- |<
- <
- 1
- >
- >|
-
辻 智, 梅村 茂2003 年 67 巻 6 号 p. 263
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーPDF形式でダウンロード (138K) -
飯塚 建興, 北 英紀2003 年 67 巻 6 号 p. 264-268
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーMo5Si3 particle reinforced Si3N4 matrix composite was fabricated by sintering molybdenum solution-infiltrated porous Si3N4, and the microstructure, mechanical properties, sliding wear and micro-tribological behaviors of 2.8 mass%Mo5Si3-Si3N4 composite were studied. Because the grain boundary glass phases protruded from the surface approximately few nanometers compared with the Si3N4 grain after polishing, the grain boundary phases contacted with the sliding pair and failed earlier than the Si3N4 grains during the sliding wear. The failures of the grain boundary phases decreased the bonding of the Si3N4 grains, and accelerated the failure of Si3N4 grains. The severe failure of grain boundary phases indicated that the wear of the Si3N4 composite mainly depend on the grain boundary. By incorporating the Mo5Si3 particle to the grain boundary phases of Si3N4, not only the mechanical properties, but also the wear behaviors were improved. The friction coefficient and the wear rate of the Mo5Si3-Si3N4 composite were 0.52, 8.9×10−9 mm2/N, respectively, under dry condition, both values∼15% lower than those for the normal sintered Si3N4. The microtribological behavior of Mo5Si3-Si3N4 composite was evaluated using the friction force microscope, and the results indicated that the friction coefficient of Mo5Si3 was about 0.34∼0.47, lower than that of the Si3N4 grain. Mo5Si3 particle showed the lower friction resistance, and exhibited the self-lubricant behavior during the sliding wear.抄録全体を表示PDF形式でダウンロード (1361K) -
有馬 則和, 高木 誠, 岩田 博之, 井村 徹, 佐々木 勝寛, 坂 公恭2003 年 67 巻 6 号 p. 269-273
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーMicrotribology of silicon single crystals is one of the important factors for the practical use of microelectromechanical system (MEMs). In this study, the effect of crystal orientation on microwear of silicon single crystal and the wear structure were investigated. Microfriction experiments using atomic force/friction force microscope (AFM/FFM) were carried out to investigate the effect of crystal orientation on the microwear depth of silicon single crystals. In these experiments, the scanning directions of a tip of AFM/FFM were ⟨100⟩ and ⟨110⟩ on Si(100) surface and ⟨112⟩ on Si(111) surface. Diamond and Si3N4 tips were used to generate the normal force of 200 and 5 μm, respectively. It was found that the depth of the wear traces generated on silicon surfaces increased in the following order: ⟨112⟩, ⟨100⟩, ⟨110⟩. Cross-sectional TEM observations of the microwear traces were carried out. It was found that small dislocation loops and lattice defects were generated in the surface region at the first stage of the microwear, and the size and the number of dislocations increased with the progress of the microwear.抄録全体を表示PDF形式でダウンロード (1073K) -
棚橋 高成, 辻 智2003 年 67 巻 6 号 p. 274-280
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーThis article describes the microtribological characterization in hinges of mobile personal computers (PCs) under the condition of boundary lubrication. We consider traction control technology for arbitrary motion of a rotating-axis system in which torque stability ensures a long lifetime under the condition of boundary lubrication. Atomic force microscopy (AFM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) are used in order to obtain an adequate solution to the boundary lubrication problem in the hinge mechanism. These microscopic observations allow a new understanding of the boundary lubrication problem. By using the finite element method (FEM) and the proposed method, it is possible to simulate the boundary lubrication realized in the hinge mechanism. It is also possible to determine the frictional force with shearing stresses of interacting metals and to model the metal adhesion structure. Supported by the experimental evidence, our results can be applied to improve the performance and quality on torque hinges in mobile PCs, and thus these can give a useful guideline for the hinge design.抄録全体を表示PDF形式でダウンロード (1833K) -
大久保 芳彦, 松橋 伸介, 田島 永善, 梅村 茂, 廣野 滋, 金子 礼三2003 年 67 巻 6 号 p. 281-285
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーNanowear tests based on atomic force microscopy (AFM) technique have been used to evaluate the wear durability characteristics of various materials and the adhesion characteristics of ultrathin films. However, the motions of wear debris during nanowear tests and the effects of wear debris on topography measurements have not been well clarified. To clarify these items, we observed the scratched surfaces of silicon single crystal by using the both tapping and contact modes at a low load condition in AFM. We have found that the motion of the wear debris of silicon was significantly affected by the observation modes, and the topography measurements of the scratched area were altered by the presence of the wear debris. Moreover, the amount of the wear debris removed from the scratched area depended on the applied load of the cantilever in contact mode AFM.抄録全体を表示PDF形式でダウンロード (648K) -
梅村 茂, 廣野 滋, 安藤 康子, 金子 礼三2003 年 67 巻 6 号 p. 286-290
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーNanowear tests based on atomic force microscopy (AFM) can be used to evaluate the wear durability of surface layers at below ultralow load conditions. The test is effective for evaluating the tribological characteristics of ultrathin films, such as the protective overcoats for hard disk drives. However, the test is unsuitable for investigating the effects of sliding speed on nm-scale wear characteristics because the relative sliding speed between the stylus of an AFM cantilever and the sample surfaces is very low under the ordinary raster scanning conditions. Therefore, a nanowear test method with increased sliding speed was developed by using a circular motion of a tube scanner. As a result, a nanowear test with the sliding speed of 2×10−2 m/s was achieved. Sliding wear experiments on sputtered carbon films using a diamond stylus show that the wear depth of the films increased when the sliding speed was increased from 1×10−3 m/s to 1×10−2 m/s. Furthermore, experimental results suggest that a nanowear test with a sliding speed of the order of 10−1 m/s can be achieved with an appropriate selection of tube scanners and by increasing the power supply capacity for the tube scanners.抄録全体を表示PDF形式でダウンロード (930K) -
田辺 郁, 茂木 徹一, 杉浦 英二2003 年 67 巻 6 号 p. 291-294
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーSemisolid casting of aluminum alloy is an advanced casting technology for the foundry industry. The advantages of semisolid casting are ease of casting at low temperature and high fluidity of the semisolid slurry, which have to contain granular, fine and homogeneous crystals. Conventional semisolid slurry processing is performed by electromagnetic stirring or mechanical stirring, both of which involve large equipment and high costs. In this investigation, we developed a simple semisolid process of AC4CH aluminum casting using an inclined cooling plate. Numerous α aluminum granular crystals nucleated on the inclined cooling plate during its flow, and the semisolid slurry ran into an isolated tundish. The crystals then became granular grains in the tundish. The semisolid slurry was cast into a horizontal continuous casting machine. The billet was 60 mm in diameter and 1000 mm in length and the casting speed was between 2 and 4 mm/s. The finest grain size of 50 μm could be obtained by casting at 897 K with a casting speed of 4 mm/s, an angle of 60°, and a length of 160 mm.抄録全体を表示PDF形式でダウンロード (735K) -
長谷川 勝哉, 和泉 輝郎, 塩原 融, 菅原 義弘, 平山 司, 大場 史康, 幾原 雄一2003 年 67 巻 6 号 p. 295-301
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーA BaZrO3(BZO) buffer layer improved in-plane alignment of SmBa2Cu3Oy(Sm123) films on MgO substrate. The reason for the effect of the BZO on the growth of Sm123 films can not be explained only by the idea of a simple lattice match, since the lattice constant of BZO is close to that of MgO. Then, a qualitative model of interfacial energy including a chemical contribution was introduced based on crystallographic consideration. The interface structure of the Sm123/BZO was observed by high-resolution transmission electron microscopy. The results indicated that the terminate plane consists of the BaO layer which is included in common both for the BZO and the Sm123 crystal structures. Further, the interfacial energies were investigated through the first-principles method. The calculated interfacial energy for a model of the Sm123/BZO interface with the BaO terminate plane was fairly lower than that of the Sm123/MgO one. Additionally, the effect of interfacial energies for hetero-epitaxial growth was discussed in view of heterogeneous nucleation. Thus, it was revealed that the BZO buffer layer plays an important role to reduce interfacial energy which leads to high possibility of the better hetero-epitaxial relationship.抄録全体を表示PDF形式でダウンロード (797K) -
宮崎 洋二, 上西 啓介, 小林 紘二郎2003 年 67 巻 6 号 p. 302-307
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーIn this paper, we examined the effect of Ag addition to the mixture of Al and Ti on the densification of synthesized Al-Ti intermetallic compounds. By the Ag addition, ignition temperature to form Al3Ti was lowered to the eutectic of Al-Ag alloy. When powder mixture with 2% Ag was heated to 973 K under 1.0 MPa, void ratio of sintered compact reduced to 0.1% and the densification was enhanced by increasing the composition of Ag. Al3Ti and Ag2Al were formed in the as sintered compact and Ag2Al decomposed to solve Ag into L12-Al3Ti by further heating at 1073 K for 14.4 ks. Although Ag addition decreased the hardness of sintered compact lower than that of Al3Ti. It retained still hardness about 400 HV for 12% Ag added specimen. The sintered compact was hardly damaged by oxidation due to the formation of protective Al2O3 after oxidizing at 1273 K for 230.4 ks.抄録全体を表示PDF形式でダウンロード (825K) -
丸山 俊介, 石黒 孝2003 年 67 巻 6 号 p. 308-314
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーIn order to investigate thermoelectric properties of Co-Sb binary films with a wide deposited composition range from 50 to 80 at%Sb, Co/Sb multi-layered films with AlN capped layer are synthesized by rf sputtering method. As-deposited films are annealed at 773 K for 1 h in a vacuum atmosphere. Transmission electron microscopy observation reveals the evolution of CoSb-β phase, CoSb2-γ phase and CoSb3-δ phase at elevating temperature, which corresponds to the variations of electrical resistance. Annealed films reproduce the phases expected from the equilibrium phase diagram. It is confirmed that the AlN capped layer is effective to suppress the sublimation of Sb and the occurrence of intergranular fracture, which leads to increase in the resistivity. Temperature dependence of Seebeck coefficients of annealed film is also measured. Because of large resistivity, the power factor of films with deposited composition of 75-80 at%Sb, which contains mainly CoSb3 phase, is smaller than the reported values. However, the film with deposited composition of 60%Sb, which contains mainly CoSb2 phase, shows large power factor, which is larger than the values reported for CoSb3 at more than 600 K. Then it is found that the CoCb2 is also promising thermoelectric material with n-type.抄録全体を表示PDF形式でダウンロード (1731K) -
熊井 真次, 今井 達也, 若菜 剛介, 加藤 雅治, 佐藤 彰一2003 年 67 巻 6 号 p. 315-323
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーA heavily cold rolled sheet of the Cu-15 mass%Cr alloy exhibited “in situ composite microstructure” including fine elongated Cr fibers in the Cu matrix parallel to the rolling direction. Difference in tensile properties was examined from the longitudinal (θ=0°) to transverse (θ=90°) directions of the cold-rolled sheet in order to characterize the tensile property anisotropy. Effects of annealing treatments were also investigated on the tensile properties and the tensile fracture surface morphology. The annealing treatments resulted in decreased proof stress and UTS, and increased elongation. Orientation dependence of the UTS from 0° to 90° exhibited V-shape manner with the minimum value at 45°, that was about 75% of that of 0° direction. Increase in annealing temperature lifted up the depth of the valley, and the 45° UTS of the 1173 K annealed sheet was 90% of that of 0° direction. Tsai-Hill equation, which predicted the orientation dependence of failure strength in off-axis tests on unidirectional laminae, fitted well to the present experimental results. The present composites showed small anisotropy both for the tensile properties and electric conductivity in spite of the regularly aligned Cr fibers along the rolling direction. Annealing treatments brought about further reduction in tensile property anisotropy.抄録全体を表示PDF形式でダウンロード (1441K) -
熊井 真次, 若菜 剛介, 尾中 晋, 加藤 雅治, 佐藤 彰一2003 年 67 巻 6 号 p. 324-330
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーYoung’s modulus measurement was casrried out in a cold-rolled Cu-15 mass%Cr in situ composite including fine elongated Cr fibers in the Cu matrix parallel to the rolling direction. The measurement was made for different orientations in order to reveal its orientation dependency (anisotropy). The free-free beam vibration method was used for precise measurement. In the as-rolled composite, the modulus decreased with increasing the angle between the fiber direction (rolling direction) and tensile axis (θ). The Young’s modulus of the composite decreased as increasing θ and reached the minimum at about 45°, and then increased with θ to the maximum at 90°. Applied micro-mechanistic analysis considering the orientation effect of the fibrous reinforcement was successful in demonstrating the θ dependence exhibiting the minimum at about 45°. Contribution of the anisotropic Young’s modulus of the Cu matrix resulting from the rolling texture should be taken into account to understand more fully the characteristic Young’s modulus anisotropy of the present composite.抄録全体を表示PDF形式でダウンロード (510K)
- |<
- <
- 1
- >
- >|