All issues
Volume 34, Issue 4
Displaying 1-6 of 6 articles from this issue
- |<
- <
- 1
- >
- >|
-
Atsushi Nishino1987 Volume 34 Issue 4 Pages 151-158
Published: June 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSLow temperature calcined catalyst, developed by Matsushita Electric Industrial Co., Ltd. has met well to consumer desire and several social problems in terms of electric appliances as a home-use catalyst. There are problems involving energy saving and the westernized way of living and eating. As a result, this catalyst has earned a good reputation as a home-use catalyst in the market of cooking appliances and heating equipments.
Depending on these appliances, three types (A, B, C) of these catalysts are available. Two types (A, B) are composed of MnO2, Zn-Mn-FeOx and Al2O3CaO and the B-type contains a platinum group catalyst in addition to the fundamental constituent. The C-type catalyst is composed of TiO2, SiO2 and Al2O3CaO which contains platinum group metals. These catalysts are the low temperature calcined type, have a high specific surface area, and washcoatless catalyst because of using Al2O3CaO.
This low temperature calcined catalyst, has actually been used for various kinds of home-use appliances for the past 10 years. Because of its high catalytic performance and inexpensive cost, it is expected that it will be applied in many fields of electrical appliances not only in Japan, but also in the global market.View full abstractDownload PDF (6532K) -
Hideaki Itoh, Tsuneaki Matsudaira, Shin Tajima, Shigeharu Naka, Hirosh ...1987 Volume 34 Issue 4 Pages 159-163
Published: June 25, 1987
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSReaction sintering process of diamond converted from graphitized pitch coke (GPC) or natural graphite (NG) was examined using the unary (Ni) and binary (Ni-Ti or Ni-Zr) solvent-catalyst systems under high pressure (6.5-7 GPa) and temperature conditions (1600°C-1700°C) for a treatment time of 10 min. Particle joining was extending regions among the diamond grains that were transformed from GPC, while growth of twins was observed in the diamond grains transformed from NG. The diamond sintered compact having more than 90% conversion ratio from GPC, was obtained in the presence of 50-70 wt% (20-37 vol%) solvent-catalyst. The grain size of diamond decreased from 20-40 μm in the unary (Ni) system to 10-20 μm in the binary (Ni-Ti or Ni-Zr) system. The Vickers microhardness of diamond phase of these sintered compacts exceeded 8000, where a typical neck growth between diamond grains was observed. The addition of 30 wt% diamond seed crystals (diameter: 0.5-3 μm) to the starting powder resulted in the further decrease in the transformed diamond grain size to 2-3 μm.View full abstractDownload PDF (5172K) -
Kennichi Sasazaki, Yoshinari Miyamoto, Shoichi Kume, Mitsue Koizumi1987 Volume 34 Issue 4 Pages 164-168
Published: June 25, 1987
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSIn order to examine the effect of cold isostatic pressing (CIP) in powder compacting process on sintering of Y-TZP with 3 mol% Y2O3, the press formed powders by uniaxial loading were isostatically compressed under water pressures from 25 MPa to 500 MPa and fired at temperatures from 1300°C to 1500°C in air. The densification was achieved at lower temperatures with increasing the magnitude of pressure in CIP treatment. The relative density reached over 99% of theoretical when the powders were sintered at 1300°C after CIP treatment.View full abstractDownload PDF (1585K) -
Yuji Kaneko, Shuji Anamoto, Atsushi Hamamura1987 Volume 34 Issue 4 Pages 169-174
Published: June 25, 1987
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSEffects of CaO and SiO2 additives on the magnetic properties, density and microstructures of the sintered compacts of Sr-ferrite were investigated. It was revealed that CaO and SiO2 additives play important roles of rapid densification and grain growth controll through the sintering process of Sr-ferrite compacts. EPMA, microstructure observation and temperature dependence of the densification showed that the densification of Sr-ferrite containing CaO and SiO2 additives was promoted by liquid phase with low melting point along the grain boundaries. The liquid phase was composed of CaO-SiO2-SrO-6Fe2O3 ternary solid solution. Magnetic properties of the sintered Sr-ferrite were strongly dependent on the amount of CaO and SiO2 additives and, in the case of CaO=0.45% and CaO/SiO2=1.25, a high quality permanent magnet (Br=4.4 KG and iHc=2.8 KOe) was obtained for an electronic oven.View full abstractDownload PDF (1982K) -
Koji Hayashi, Junichi Ogiwara1987 Volume 34 Issue 4 Pages 175-180
Published: June 25, 1987
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSThe optical and SEM microstructures and the room temperature mechanical properties of Si3N4-Er2O3-CaO-6 mol%, Al2O3 compact sintered under 0.1 MPa of nitrogen gas at 1973-2073 K for 3.6 ks were mainly investigated as a function of Er2O3 (2, 4, 8 mol%) and GaO (0-10 mol%) contents.
The results obtained were as follows; (1) The additions of Er2O3 and CaO to Si3N4-Al2O3 compact increased the relative density. (2) The a-β phase transformation and the grain growth of Si3N4 phase were restricted with increasing CaO content. (3) The crystalline grain boundary phases in Si3N4-8 mol%Er203-CaO-A12O3 compact were found to be mainly Er4Si2O7N2 and Er2Si3O3N4 at small and large CaO contents, respectively. (4) The transverse-rupture strength showed a maximum generally at about 8 mol%Er2O3 and 2 mol%CaO. The hardness increased with increasing CaO content. The result on the strength was discussed in relation to the relative density, grain size, kinds of grain boundary phases, fracture toughness, fracture source, etc.View full abstractDownload PDF (4838K) -
Takeshi Sadahiro, Kaoru Sobata1987 Volume 34 Issue 4 Pages 181-184
Published: June 25, 1987
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSEffect of plastic zone at the tip of small defect on the fracture toughness calculated with rupture strength and defect size was studied.
(1) Fracture toughness evaluated by approximating the cross section of the small fracture defect with the inscribed circle or the ellipse is smaller than that determined by the Bridge Indentation method based on linear elastic fracture mechanics. The difference between the two values increases with the decrease of defect size and the increase of Co content.
(2) Fracture toughness estimated by taking account of the yielding of the plastic zone at the tip of defect agrees with the measured value by the BI method.View full abstractDownload PDF (265K)
- |<
- <
- 1
- >
- >|