巻号一覧
16 巻, 5 号
選択された号の論文の4件中1～4を表示しています
- |<
- <
- 1
- >
- >|
-
TeおよびMoO3添加の影響飯村 勉1969 年 16 巻 5 号 p. 217-223
発行日: 1969/10/25
公開日: 2009/12/04
ジャーナル フリーEffect of Te and MoO3 on the grain structure and electromagnetic properties of Mn-Zn-Mg-ferrites have been studied.
(1) High permeability materials were obtained when sintered in two steps. With Te or MoO3 added, the first step was performed in air at 1350°C for 1 hour, and the second, in nitrogen at 1150°CC for 3 hours.
(2) Uniformly, grained matrix was obtained by Te or MoO3, the addition of Te inhibitied grain growth, whereas MoO3 promoted.
(3) Lattice constant was increased by Te but not significantly by MoO3, which could be explained by the high solubility of Te in ferrites.
(4) Sintered density decreased markedly with the increasing To or MoO3.
(5) Electrical resistivity increased considerably up to 0.5% addition of Te.抄録全体を表示PDF形式でダウンロード (4700K) -
桑本 英彦, 斉藤 俊次郎, 武井 武1969 年 16 巻 5 号 p. 224-229
発行日: 1969/10/25
公開日: 2009/05/22
ジャーナル フリーThe crystal size of the ferrites formed hydrothermally from the mixtures of 2α-FeOOH +Zn(OH)2, 2α-FeOOH+NiO or 2α-FeOOH+Co(OH)2, was found to depend on the pH of the medium, and large cubic crystals were observable in alkaline medium, in which complex ions bearing Zn++, Ni++ or Co++ were stable.
In case of the synthesis of these ferrites from coprecipitates, the sizes were very small and nearly independent of the pH.
Copper ferrites were formed only from the coprecipitates or wet mixtures.
Grain growth of the ferrites was scarcely observable during the treatments within 10 hours.
Based on these observations, brief discussions were given on the mechanism of the formation.抄録全体を表示PDF形式でダウンロード (3954K) -
山村 勝美, 笠井 昌巳, 針谷 宏1969 年 16 巻 5 号 p. 230-234
発行日: 1969/10/25
公開日: 2009/05/22
ジャーナル フリーThe authors have succeeded in obtaining a new and improved tool material which is harder than any existing cemented carbide by diffusing boron on the surface of the cemented carbide or cermet, the best tool material up to the present, by means of the electrolysis in the molten salts.
By using the test pieces of WC-Co alloy comprising cobalt of 4, 7 and 10% respectively, boron was diffused by means of electrolysis in the molten salts. We found that the surface hardness was increased by about 40 to 70%.
This increase in hardness is due to the boride produced by the combination of boron and cobalt. The diffused layer was 40μin thickness.
After a practical running test, it was found that the tool of this treated WC-Co alloy had the tool life three times as that of the tool without treatment and working efficiency was also increased.抄録全体を表示PDF形式でダウンロード (2320K) -
鈴木 寿, 山本 孝春1969 年 16 巻 5 号 p. 235-239
発行日: 1969/10/25
公開日: 2009/12/04
ジャーナル フリーThe spotted structures were confirmed by the present authors to develope in WC-Co alloys containing small amount of tantalum and niobium carbide, respectively. And, phenomena relating to the structures were investigated. The fine and coarse-grained WC-(10-20)%Co alloys having additional carbides of 0.5-2.0% were used as specimens.
The results obtained were as follows : (1) The spotted structures appeared to be caused by the precipitation from the liquid phase enriched with tantalum carbide or niobium carbide. The enriched phase was formed probably due to the separation of liquid binder phase during the cooling of specimens. (2) Spotted phase in each alloy was identified by x-ray or electron diffraction and x-ray microanalysis as (Ta, W) C1-x or (Nb, W) C1-x, i.e., nonequilibrium phase containing abnormally large amount of tungsten. (3) The strength of the alloys was lowered markedly by the appearance of these structures.抄録全体を表示PDF形式でダウンロード (6653K)
- |<
- <
- 1
- >
- >|