巻号一覧
29 巻, 7 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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牧野 和孝, 日高 重助, 牧 春彦, 三輪 茂雄, Thomas P. Meloy1982 年 29 巻 7 号 p. 229-235
発行日: 1982/09/25
公開日: 2009/05/22
ジャーナル フリーFormation mechanism of particle existing density distribution in penetration testing of powder bed is fundamentally discussed. The particle existing density distribution change in penetration testing, of which geometrical the structure is simple and the physical meaning is easier to be understood, is observed by static X-ray radiographs. It is clearly shown that the particle existing density distributions around a plunger exhibit periodicity, reflection at wall, diffraction through a slit and interference between two slits. And the spacial distribution of displacement vector is pointed out to be one of the important factors which determine these phenomenon mentioned above.抄録全体を表示PDF形式でダウンロード (4870K) -
Fe(OH)2の空気酸化によるFe3O4生成に関する始発pHと溶存酸素について近藤 正樹, 中島 信顕, 平沢 輝高1982 年 29 巻 7 号 p. 236-240
発行日: 1982/09/25
公開日: 2009/05/22
ジャーナル フリーThe variation of DO (dissolved oxygen), pH and ORP in the course of Fe(OH)2 oxidation, the yields of Fe3O4 determined by measuring the concentrations of Fe(II) and total Fe ions in the suspension and the settling velocity of final oxidation products were studied.
Completion of Fe(II) oxidation was detected by measuring the DO concentration or ORP in alkaline suspensions. During the oxidation, DO value was not detected and the rate of Fe(II) oxidation was shown by the product of KLa (oxygen transfer coefficient) by the saturated concentration of oxygen in the suspension.
The initial pH suitable for Fe3O4 formation was 11.5-12.5 at 40°C or lower and 11.5-13 at 60°C or higher, whereas the settling velocity of the final products became faster as the initial pH was lower.抄録全体を表示PDF形式でダウンロード (319K) -
Fe3O4生成に及ぼすFe(OH)2酸化速度の影響近藤 正樹, 中島 信顕, 平沢 輝高1982 年 29 巻 7 号 p. 241-245
発行日: 1982/09/25
公開日: 2010/07/12
ジャーナル フリーThe aqueous suspensions containing 0.05, 0.10 and 0.20 M Fe(II) with pH 12 were subjected to oxidation with air at 20, 40, 60 and 80°C. The time duration, θe, needed for complete oxidation of Fe(II), which had been detected by the presence of dissolved oxygen in the suspension, was limited between 15 and 180 min by varing the oxidation rate.
Relation between the yield of Fe3O, (X) and θe was obtained as follows; dX/dθe =k(1-X )2 or 1/(1-X)=kθe+1, where k is a function of the oxidation temperature.
The Fe3O4 content of the oxidation product was affected by the oxidation rate and temperature. Settling velocity of the product became faster with increasing X for X≥0.6.抄録全体を表示PDF形式でダウンロード (312K) -
永井 宏, 武林 慶樹, 藤川 武志, 庄司 啓一郎1982 年 29 巻 7 号 p. 246-249
発行日: 1982/09/25
公開日: 2009/12/04
ジャーナル フリーThe isothermal oxidation behavior of sintered Fe-20Cr alloys with various amounts of Y2O3 and La2O3 dispersion was investigated in the temperature range from 1273 to 1473 K in air. Dispersion of Y2O3 and La2O3 significantly improved the oxidation resistance. The amounts of Y2O3 and La2O3 dispersion needed to suppress the break-away oxidation increased with increasing oxidation temperature. The improvement effect of La2O3 on the oxidation resistance was stronger than that of Y2O3. The grain size of the alloy decreased with increasing the amounts of Y2O3 and La2O3 dispersion. However, there was no apparent correlation between the oxidation resistance and the grain size of the alloy. The results of IMA analyses showed that the composition of the Cr2O3 scale formed during the early stage of oxidation was strongly dependent on the amounts of Y2O2 and La2O3 in the alloy.抄録全体を表示PDF形式でダウンロード (2768K) -
永井 宏, 武林 慶樹, 渡辺 和弘, 庄司 啓一郎1982 年 29 巻 7 号 p. 250-255
発行日: 1982/09/25
公開日: 2009/12/04
ジャーナル フリーThe isothermal oxidation behavior of sintered Fe-20Cr alloys with a simultaneous addition of Y2O3-A1, Y2O3-Si and La2O3-Si was investigated in the temperature range from 1273 to 1523 K.
Simultaneous addition of Al and Si with rare earth oxides significantly reduced the oxidation rate of the alloy and suppressed the break-away oxidation. In the case of the simultaneous addition of rare earth oxides with Si, La2O3 was more effective than Y2O3, especially at higher temperatures. The spalling of the scale was also excellently suppressed by the simultaneous addition of Al and Si with rare earth oxides, although the singular addition of Al and Si accelerated the spalling of the scale.
Dense internal oxide layer of Al2O3 and SiO2 formed beneath the Cr2O3 scale in the alloys containing Al and Si. However, it seemed unlikely that the simultaneous addition of Al and Si with rare earth oxides enhanced the internal oxidation of Al and Si and changed the shape of the internal oxide layer. From the result obtained in this study, it seemed reasonable that the excellent improvement in the scale adhesion induced by the simultaneous addition of Al and Si with rare earth oxides was not explained only by "keying" and "vacancy sink" models.抄録全体を表示PDF形式でダウンロード (2802K) -
鈴木 寿, 林 宏爾, 谷口 泰朗1982 年 29 巻 7 号 p. 256-260
発行日: 1982/09/25
公開日: 2009/12/04
ジャーナル フリーThe high temperature oxidation tests for WC-14-Co alloy containing nitrogen, i.e., WC-β(N)-Co alloy (β: WC-TiC, β(N): WC-TiC-TiN solid solution) were made in air at 973-1173K and the results were compared with those of WC-Co, WC-β-Co, WC-β-TaC-Co alloys, etc.
The oxidation resistance of WC-fl-Co alloy was remarkably improved by the nitrogen addition. The beneficial effect of TaC addition on the resistance was confirmed. The oxidation of cemented carbides was found in common to be controlled by the reaction at the interface between oxide layer and alloy matrix. The improvement in oxidation resistance of the alloys containing nitrogen or TaC would be understood in view of the fact that β(N) or triple carbide particles, being considered to act as obstacles to the diffusion of oxygen, inclined to remain unoxidized in the scale near the interface.抄録全体を表示PDF形式でダウンロード (3438K)
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