巻号一覧
30 巻, 1 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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羽田 紘一, 小島 浩, A.H. Morrish1983 年 30 巻 1 号 p. 1-5
発行日: 1983/01/25
公開日: 2010/07/12
ジャーナル フリーNiFe2O4 small particles (in the few hundred angstrom size range and up) have been prepared by a chemical precipitation method and subsequent heat treatments, and their magnetic properties have been explored in particular reference to their magnetic structure for its smallness of the particle size. The magnetic moment at low temperatures is appreciably lower than the value reported for bulk material. Mossbauer spectra, obtained with a longitudinal high magnetic field applied, unambiguously establish that a non-collinear structure exists that is most pronounced for the smallest particles. The analysis indicates that a surface effect of the crystallites which make up a particle is the origin of this phenomenon.抄録全体を表示PDF形式でダウンロード (2355K) -
仙名 保, 久野 洋1983 年 30 巻 1 号 p. 6-11
発行日: 1983/01/25
公開日: 2009/05/22
ジャーナル フリーReactants of NiO-MoO3 binary solid state reaction are preliminary ground either separately or together in air (dry) or in cyclohexane (wet) by a laboratory vibro-mill. Subsequently, the rate of nickel molybdate formation on heating at 600°C in air was determined by applying Dander rate equation. Dry grinding of NiO followed by an intimate mixing with MoO3 and by wet co-grinding brought the highest rate, due to the large amounts of lattice imperfections introduced into NiO. Preliminary grinding of MoO3, on the other hand, was effectiveless, because of high degree of agglomeration which hinders the intimate mixing on subsequent wet vibromilling. Dry co-grinding was also effective, although less amounts of lattice im-perfections are introduced, compared with dry separate grinding, presumably because of originating precursory products at the contact points of foreign reactant particles during grinding.抄録全体を表示PDF形式でダウンロード (1720K) -
石垣 尚幸, 真島 一彦1983 年 30 巻 1 号 p. 12-20
発行日: 1983/01/25
公開日: 2009/05/22
ジャーナル フリーSm (Co, Fe, Cu)7 powder compacts were sintered in three different kinds of sintering atmospheres; i.e., hydrogen, argon and vacuum of 10-5 Torr.
The remarkable contraction due to the liquid phase sintering occured at a sintering temperature higher than 1220°C, where the amount of shrinkage increased in the order of argon, vacuum and hydrogen atmos-phere.
Higher density specimen were obtained and the alignment ratio of the grains was successfully improved by the sintering in hydrogen atmosphere.
Therefore the use of the hydrogen atmosphere led to enhance the resultant magnetic properties of Sm(Co, Fe, Cu)7 permanent magnet alloys.抄録全体を表示PDF形式でダウンロード (5800K) -
鈴木 寿, 林 宏爾, 高嶋 好夫, 並木 尚己1983 年 30 巻 1 号 p. 21-24
発行日: 1983/01/25
公開日: 2009/05/22
ジャーナル フリーThe WC-β-Co alloys having several amounts of nitrogen were prepared by using WC-TiC-TiN solid solution (named β(N); nitrogen content, about 4%), and sintering in vacuum or in nitrogen gas of up to 10kPa. Some properties of alloys such as microstructure, lattice parameter of binder phase or β(N) phase, and transverse-rupture strength, etc., were studied. It was noted that the strength of alloys tended to decrease with increasing nitrogen content of β(N) in the alloy; however, the strength after HIP was excellent, when the nitrogen content of β(N) was less than about 3%.抄録全体を表示PDF形式でダウンロード (1440K) -
鈴木 寿, 林 宏爾, 並木 尚己1983 年 30 巻 1 号 p. 25-28
発行日: 1983/01/25
公開日: 2009/12/04
ジャーナル フリーTwo sorts of green compacts were made by using β(WC-TiC solid solution) and β(N)(WC-TiC-TiN solid solution containing 4.2%N) starting powders. They were nitrified at 1523 K in N2 (nitrogen atmosphere) of 2.7-20kPa and subsequently sintered at 1673-1873 K in N2. The microstructure, hardness, transverse-rupture strength, etc., of sintered compacts were studied.
Fine WC particles were precipitated from f or β(N) when β or β(N) compact was. nitrified, resulting in the mixture of nitrogen contained i and WC phases. The dense compacts were obtained when the mixture was sintered at temperature above about 1823 K. The compact prepared by using β(N) powder showed in particular a very high hardness and an excellent transverse-rupture strength.抄録全体を表示PDF形式でダウンロード (2936K) -
組織と機械的性質明智 清明, 塙 健三, 中川 威雄1983 年 30 巻 1 号 p. 29-35
発行日: 1983/01/25
公開日: 2009/12/04
ジャーナル フリーThe mechanism of graphite nodularization and how to control graphite morphologies in sintered products of cast iron swarf powder, Fe-Si-C mixed powders, or Ni-C mixed powders have been investigated.
When the powder contains carbon less than the maximum solubility at the given sintering temperature, all carbon atoms dissolve in solid solution (γ-Fe or Ni-phase) during sintering and precipitate as the graphite into the pores during cooling. Consequently, if the pores in the sintered products are spherical by long-time sintering or powder forging processes, spherical frames for the graphite to grow in nodular morphology, can be provided. Then for example, the products (Imass%C) made from mixtures of cast iron swarf powder and reduced iron powder show the high tensile strength of 95 kgf/mm2 by long-time sintering (1150°C⋅20 hr).
On the other hand, when carbon contents are more than the maximum solubility, no nodular graphite can be obtained because of residual undissolved graphite.抄録全体を表示PDF形式でダウンロード (7133K)
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