Fabrication and characterization of ceramics/Carbere composite by spark plasma sintering method

In this research, CSCNT (cup-stacked type carbon nano tube, Carbere) was mixed with three kinds of ceramic matrix such as SiC, WC, TiB2 by 3vol%. The ceramics/Carbere composites were sintered by spark plasma sintering method to improve mechanical and electrical properties such as the toughness, the flexural strength, the electric conductivity. Carbere existed at the grain boundaries of ceramics. The flexural strength was enhanced by 1.35 times in the WC system. The fracture toughness (KIC value) was improved about 1.1 times for the three systems. The electrical conductivity was improved about 390 times in the SiC system.departmental bulletin pape

Manufacturing and mechanical properties of spark plasma sintered SiC/VGCF composite ceramics

In order to produce a carbon nano-fiber reinforced composite ceramics SiC/VGCF, 0-12.5mass% (2.5mass% step) of VGCF is added to the SiC matrix, and using the spark plasma sintering (SPS) method, it was sintered at 1700-1750°C for about 11 minutes under a mold pressure of 40 MPa and evaluated for its properties. A relative density of 99.8% or more was obtained at the range from 2.5 to 10.0 mass%VGCF. The bending strength showed the maximum strength of 528 MPa at 5 mass%VGCF, which was 1.11 times higher than 474MPa at 0%VGCF. The fracture toughness 5.0 MPa･m1/2 at 5 mass%VGCF was improved by 1.11 times from 4.52 MPa･m1/2 at 0%VGCF. The electrical conductivity showed 0.12 to 2318.0 S/m, which greatly improved in proportion to the VGCF content.departmental bulletin pape

カーボンナノ材料 : 磁性微粒子複合体の合成とその特性

departmental bulletin pape

境界抽出ファジィテンプレートを用いた活性炭の透過電子顕微鏡像からの気孔解析

applicationActivated carbons are used, as absorbent materials, in various places. It so numbers of pores that the surface areas of them become very large. The analysis of the microstructure of the pores, especially regarding the shape or morphology of the pores, has not yet been adequately clarified. Generally we use transmission electron microscopy (TEM) images of them in order to analysis the property. TEM provides a very useful technique for analyzing porous materials, because it gives visual and detailed information about the pores. We have tried to use TEM of activated carbons, combined with image analysis, in order to make TEM a quantitative technique. It is important that the pore boundaries are clarified to analyze the pore structure, but extraction of the edges of pores is difficult by conventional techniques because of their irregular density sifts in the TEM images. In this work, we tried to extract of the pore boundaries of the activated carbons by using fuzzy template obtained from notion of a fuzzy phase, which was established as set with an ambiguous limit by the others. In this report we show the good result which was obtained by the experiments.departmental bulletin pape

高分子フィルム中におけるカーボンナノファイバーの分散と配向化の試み

departmental bulletin pape

画像処理を用いた高密度等方性黒鉛材料の気孔構造の解析

applicationStrength parameters of isotropic high-density graphite are thought to be strongly correlated to pore structure of the graphite from experimental results on fracture toughness. In this paper, we present quantitative analysis of pore structure in the isotropic graphites by means of an image processing of a polarizing microscope image of the material. Power spectra of the polarizing microscopic images of the isotropic graphite are obtained by the 2-dimensional fast Fourier transform. These results indicate that the structure of the pores and the other solid parts of the graphite are almost isotropic. Distribution of the area, the number, the circularity, and the fractal dimension of cross-section of the pores are measured, and the pore structure is analyzed quantitatively.departmental bulletin pape

カーボンナノファイバーの化学修飾と配列化の試み

departmental bulletin pape

高速移動物体上の符号検出

applicationThe marks, which indicate the standard, the year of production and others, printed on a cable are important parts of the product. So it is indispensable to check the marks. The producing speed of the cable comes up to 10m/sec. In order to practice economy and automation it is necessary to detect the marks printed on the fast moving cable. In this study, we examined the characteristics of some opt-electronics devices and selected one of them. Using the selected device the marks printed on a fast moving object were detected.departmental bulletin pape

Manufacture and property of each Ni, Ti, NiTi metal/graphene composite by ultrasonic-assisted hot-pressing method

The composites containing 0% or 15 vol% of graphene (GnP) for each matrix metal of Ni, Ti and NiTi were prepared by hot pressing method with or without assistance of ultra-sonic waves, and the mechanical and electrical properties were compared. The relative density of Ni and Ti-based metals with 0% GnP content was 96% or higher. When 15 vol% GnP was included, it decreased to about 84-94%. The relative density of the NiTi with 0% GnP content increased from 90.6% to 98.2% by applying ultrasonics. However, when GnP was included, it decreased to 91.1-92.4%. The mechanical properties showed proportional to the relative density. The electrical conductivities of pure Ni, Ti, and NiTi metals were 9.09, 1.78 and 1.19 MS/m, respectively. The electrical conductivity of composite with 15vol% of GnP decreased, particularly for Ni-based and Ti-based materials, which decreased to 22-53%.departmental bulletin pape

Manufacture and mechanical properties of sintered composite of VGCF-contained TiB2, SiC, Si3N4 ceramics by hot pressing method

TiB2, SiC and Si3N4 composite ceramics containing 0 or 3.23mass%VGCF (vapor grown carbon nano-fiber) were prepared by hot-press sintering method. The distribution of VGCF and mechanical and electrical properties were compared. By addition of VGCF, the relative density improved from 93.3 to 99.8% for TiB2, from 96.9 to 98.3% for SiC, and from 96.5 to 99.4% for Si3N4. In the TiB2 system, VGCF were not found in the SEM structure. In the SiC system, a large number of VGCFs were observed at the grain boundaries of SiC, and the VGCFs were uniformly dispersed. Mechanical properties such as three-point bending strength and fracture toughness were improved by approximately 1.6 times. The electrical conductivity was improved about 350 times in the case of SiC by the addition of VGCF.departmental bulletin pape