巻号一覧
19 巻, 5 号
選択された号の論文の6件中1～6を表示しています
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上原 保彦1972 年 19 巻 5 号 p. 183-188
発行日: 1972/10/25
公開日: 2009/12/04
ジャーナル フリーMechano-chemical reactions and.structural changes of some spinel-type ferrite powders by grinding have been investigated.
It was observed that the mechano-chemical reaction occurred on the MgFe2O4 particle surface during wet grinding and a thin layer containing combined water was formed on the surface. The thickness of the layer was almost constant independently of the grinding duration. The calculated values of OH's/100Å2 (the number of OH radical per unit surface area) for wet ground samples were in the range of 62 to 66. The Mg0.86Mn0.43Fe0.71O4 powder was subjected to various wet grinding treatments using the following three types of mill: 1) attritor, 2) ball mill, 3) vibratory mill. The thickness of the layer containing combined water was nearly constant independently of a variety of grinding treatments. The calculated values of OH's/100Å2 were in the range of 79 to 92.
The powder of ordered Li0.5Fe2.5O4, in the spinel structure of which the Li and Fe ions make 1:3 ordering at the octahedral sites, were wet ground in a ball mill. As a result, the long-range order parameter decreased with increasing the grinding time.
In the case of the CuFe2O4 powder, the tetragonal structure was gradually transformed to the cubic one with grinding. The mechanism of this mechanochemical polymorphic transformation can be explained by the destruction of a cooperative Jahn-Teller effect by grinding.抄録全体を表示PDF形式でダウンロード (357K) -
中塚 勝人, 岡田 豊明, 戸板 公志, 下飯坂 潤三1972 年 19 巻 5 号 p. 189-192
発行日: 1972/10/25
公開日: 2009/12/04
ジャーナル フリーThe mineral species of co-precipitated products from a mixed solution of ferric and copper sulfates (Fe/Cu=2.0) at 20-200°C were discriminated by means of X-ray diffraction, and the crystallographic properties of copper ferrite contained in it were investigated in relation to cubic-tetragonal transformation.
The mineral phase of the precipitates, owing to X-ray diffraction, was one of the four states of amorphous, CuO, the mixture of CuO and Cu-ferrite and the mixture of CuO, Cu-ferrite and a-hematite depending on the temperature and pH.
The crystal systems of obtained Cu-ferrites were whole cubic regardless of aging conditions. When they were treated by heating (740°C), the crystal systems of Cu-ferrites formed in neutral and slightly alkaline solutions (pH 6-11) changed to tetragonal, but those in strongly high alkaline solutions remained unchanged. From the chemical analysis or measurements of lattice constant on Cu ferrite containing sodium by dry method, it was supposed that the Cu-ferrite obtained in strongly alkaline solution contains sodium ion in cubic lattice and it prevents the cubic-tetragonal transformation of Cu-ferrite.抄録全体を表示PDF形式でダウンロード (276K) -
貝田 翔二, 磯部 満郎, 北村 道雄, 三田 洋二1972 年 19 巻 5 号 p. 193-196
発行日: 1972/10/25
公開日: 2009/05/22
ジャーナル フリーA study was carried out to obtain a detailed knowledge about the precipitation process of the Fe2O3 phase in a series of sintered zinc ferrites containing excess Fe2O3 and B2O3 additives. In the specimen containing excess Fe2O3, the precipitation of Fe2O3 with Widman shape was observed in the crystal grains. The precipitation of Fe2O3, however, along the grain boundary and in voids was observed in the specimen containing B2O3.
The cause of such anomalous change in microstructure was discussed in connection with the mobility of Fe atoms.抄録全体を表示PDF形式でダウンロード (5345K) -
II. Dependence of the Electrical Conductivity of High Purity Polycrystalline Rutile on Equilibrium Oxygen Pressure and TemperatureKazumasa Hirajima, Tomoaki Sasaki, Kenzo Hijikata1972 年 19 巻 5 号 p. 197-206
発行日: 1972/10/25
公開日: 2009/05/22
ジャーナル フリー1) The electrical conductivity of high purity polycrystalline rutile prepared from T.B.T. was determined as a function of the oxygen partial pressure (10-2-103 mmHg) at 800° and 900°C. The electrical conductivity has been found proportional to Po2-1/6.
2) The frequency dispersion of the conductivity was not observed at 800° and 900°C, and the dc conductivity data corresponded to those of ac.
3) The relation logσ vsl/T was well represented by a straight line having a slope 1.48eV in pure oxygen gas and in the temperature range 600°-1000°C.
4) In the thermoelectric power measurements, the cooler end of the specimen was always negative with respect to the hotter end indicating negative charge carriers, electrons, but the quantitative values could not be obtained with a reproducibility.
5) It may be concluded that the defect of rutile with a "nearly intrinsic" character involves oxygen vacancies at 800° and 900°C in the oxygen partial pressure 10-2-103 mmHg, and it appears to imply that p-type conduction did not belong to the intrinsic behavior of rutile below atmospheric pressure.抄録全体を表示PDF形式でダウンロード (493K) -
高津 宗吉, 新崎 康世1972 年 19 巻 5 号 p. 207-212
発行日: 1972/10/25
公開日: 2009/12/04
ジャーナル フリーChanges of carbon and oxygen in the compacts of WC-5% and 13%Co mixed powders during heating in the temperature range, 300-1400°C, in H2 atmospheres were investigated by means of chemical and gaschromatographic analysis. Hydrogen gases used were as-received H2 including 0.4mol% H2O and 0.03% O2 and treated H2, in which the impurities were converted into CO by reaction with graphite at 1000°C. The following reactions were observed. (a) Reduction by H2 occurred over all temperatures. (b) Interaction of carbon and oxygen in the powders occurred at above 900°C and it increased with increasing the temperature rose. (c) Decarbonization by H2 was observed at the temperatures ranging from 600 to 1300°C, and had a maximum at about 1000°C. (d) In the as-received H2, decarbonizing reactions with H2O and O2 were remarkably observed at above 700°C, Reactions (a) and (c) occurred rapidly in the beginning of heating and almost finished within 1 hour. Reactions (b) and (d) were observed throughout the heating, but decarbonization by the reaction (b) was comparatively small.抄録全体を表示PDF形式でダウンロード (398K) -
大黒 貴, 増山 不二光, 森 隆夫1972 年 19 巻 5 号 p. 213-219
発行日: 1972/10/25
公開日: 2009/12/04
ジャーナル フリーTo account for the strengthening mechanism in the dispersion hardened 13CrMoTi steel, an analysis of the structural change during the heating at the specimens subjected to hot-working after sintering was made by means of X-ray diffraction method. The results obtained are as follows:
1) The internal strain is introduced into the matrix of the sintered alloys by the hot working. However, very small lattice strain is found in the as hot-extruded specimen, despite of the higher degree of the hot working. This is owing to the recrystallization occurred probably in the cooling stage after extrusion.
2) Structurall analysis demonstrated that the work-hardened structure in the sheath forged specimen is retained even after heating for a long time at the elevated temperature. This offers an explanation for the strengthening increment associated with the hot working of the oxide dispersion strengthened material.抄録全体を表示PDF形式でダウンロード (4574K)
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