巻号一覧
21 巻, 3 号
選択された号の論文の4件中1～4を表示しています
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岡本 明, 田村 秀夫, 吉田 哲郎1974 年 21 巻 3 号 p. 66-70
発行日: 1974/06/25
公開日: 2009/12/04
ジャーナル フリーMorphological study on the surface of sintered Cu 0.75Fe 2.25O 4, which was annealed for a long time in the condition without accompanying any crystal growth, were carried out to clarify the relation between the surface configuration and its orientation, and to determine the anisotropy value of surface free energy.
The annealing of ferrite sealed in an evacuated quartz tube resulted in the surface formed by (111) plane and continuous surface which was variously oriented near to (001). The observed surfaces were classified into three types according to the constituent plane; (1) surface formed by only continuous surfaces, (2) surface containing steps consisted of continuous surfaces and (111) planes, and (3) surface containing the steps consisted of continuous surfaces and (111) and (111) planes.
A relation between the surface orientation and surface pattern was derived and plotted in a stereographic projection triangle.
Applying the Herring equation to the diagrams which show the relation between surface configuration and its orientation, the ratios of surface free energy of continuous surface to that of (111) plane were determined as 1.37, 1.25 and 1.11 at 1050°, 1100° and 1150°C respectively.抄録全体を表示PDF形式でダウンロード (3739K) -
上原 保彦1974 年 21 巻 3 号 p. 71-75
発行日: 1974/06/25
公開日: 2009/05/22
ジャーナル フリーAn experiment has been conducted to clarify the milling effect upon the sintering rate in the LiMInZn ferrite. The ferrite powder was wet-milled by a vibration mill for various times ranging from 2 to 24 hours and the linear shrinkage of the powder compacts during heating was measured. The shrinkage ratios, log (ΔL/L0)100min were obtained by sintering the samples at various temperatures for 100 minutes and they. were plotted against 1/T. This relation has indicated that all linear lines have a knee of gradient at about 750°C. A sample milled for 2 hours has an apparent activation energy for sintering of 13 kcal/mol in the temperature range between 600 and 750°C, and a sample milled for 24 hours has that of 89 kcal/mol. This may be infered that amorphous laver on the surface of the milled particles prevents the densification by the grain boundary diffusion process. Above about 750°C, the sintering has progress at a greater rate in a sample milled for longer hours so that a sintered body of small grain with high density was obtained. The examination of the milling effect on the performances of a memory core has indicated that the signal-to-noise ratio of core output and their mechanical strength are remarkably improved with an increase in milling time, while the switching speed becomes somewhat slower.抄録全体を表示PDF形式でダウンロード (2840K) -
戸田 堯三, 野呂 孝信, 牟田 明徳1974 年 21 巻 3 号 p. 76-81
発行日: 1974/06/25
公開日: 2009/12/04
ジャーナル フリーIn a ternary system of Al2O3-Y2O3-MgO, the porosity, in- line transmittance and grain growth of sintered body were studied. The results obtained were summerized as follows. (1) The optimum composition of ternary system to obtain high transmittance was Al2O3-0.1 wt% Y2O3-0.025-0.05 wt% MgO, and the in-line transmittance (thickness 0.5 mm, wave length 300-1100 mμ) of the sample sintered at 1700°C for 5 hrs in H2 was approximately 70%. (2) The contribution of Y2O3 addition to grain growth during sintering of Al2O3-MgO system was very small. (3) The sintering process to achieve translucent Al2O3 were believed to be different from those of other transparent ceramics. It was supposed that diffusional removal of vacancies in Al2O3 was accelerated by the addition of Y2O3 at near 1700°C, and it contributed to increase of transparency of Al2O3-Y2O3-MgO ceramic.抄録全体を表示PDF形式でダウンロード (452K) -
I Effect of Oxygen Pressure on Shrinkage and Electrical Resistance of Yttria Powder Compacts during SinteringTomoaki Sasaki, Yoshiyuki Innami, Kenzo Hijikata1974 年 21 巻 3 号 p. 82-86
発行日: 1974/06/25
公開日: 2009/05/22
ジャーナル フリーIsothermal shrinkage and electrical resistance of powder compacts of highly pure yttria (purity: 6 nine) were simultaneously measured over the temperature interval 800°to 950°C in an atmosphere of nitrogen, air and oxygen during sintesing. By X-ray diffraction analysis, no new phase of yttria was detected in the range of temperature and oxygen partial pressure investigated. It was found that the oxygen partial pressure has an effect on both the shrinkage and electrical resistance of powder compacts of yttria. The isothermal shrinkage increased and the electrical resistance decreased with increasing oxygen partial pressure. The result of thermoelectric power measurement indicated p-type character in all experimental conditions studied.
From these results, it may be concluded qualitatively that predominant defect in high purity yttria is excess oxygen defects resulting from the deviation of stoichiometry more or less associated with electron holes.抄録全体を表示PDF形式でダウンロード (269K)
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