巻号一覧
34 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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奥谷 克伸1987 年 34 巻 5 号 p. 189-197
発行日: 1987/07/25
公開日: 2009/05/22
ジャーナル フリーRelationships between magnetic properties and composition, raw materials, additives, sintering profiles and production process for Mn-Zn ferrite were investigated. The adequate selection of raw materials and processing parameters is a key of the control of microstructure and electromagnetic property. A new production method of ferrite raw material by spray roasting was developed. This method has some advantages such as high purity, low cost and simple process.
Mn-Zn ferrite with superior performance for power applications was obtained by this method.抄録全体を表示PDF形式でダウンロード (1686K) -
黒木 英憲1987 年 34 巻 5 号 p. 198-204
発行日: 1987/07/25
公開日: 2009/05/22
ジャーナル フリーThe swelling of cylindrical compacts, 10 mm(d)×10 mm (h) in size, was measured with a micrometer during each production process; after pressing at 2-8 t/cm2 (196-784 MPa), after dewaxing at 500°C (773K) for 30 min, and after sintering at 900°C (1173 K) for 5-180 min.
Compacts pressed under higher pressures (588-784 MPa) swelled during sintering, while those pressed under lower pressures (196-392 MPa) shrank. Both the swelling and the shrinkage of compacts pressed with die-wall lubrication and sintered in cracked ammonia gas were larger than those of compacts pressed with powder lubrication or sintered in argon gas. Dimensional change during sintering was larger in swelling or smaller in shrinkage, in the pressing direction than in the lateral direction.
The sintering time for the swelling of electrolytic copper powder compacts in argon gas was longer than that of the compacts sintered in cracked ammonia gas or of the compacts made from atomized copper powder.抄録全体を表示PDF形式でダウンロード (450K) -
真島 一彦, 吉村 義仁, 庄司 啓一郎1987 年 34 巻 5 号 p. 205-210
発行日: 1987/07/25
公開日: 2009/05/22
ジャーナル フリーThe effect of eutectoid β stabilizing elements of Cr, Mn, Fe, Ni, Cu, and Si on the sintering characteristics and tensile properties of Ti powder compacts was investigated, and compared with the case of Co addition carried out in a previous paper.
The additional elements of Fe and Ni had the similar good effect on the densification of Ti powder compacts to the Co addition, where the sintered density ratios increased with additional amount of Fe and Ni. In the case of Si addition, the extremely high sintered density ratio of 99% was obtained for the 2 wt%Si specimen, while it decreased abruptly with increasing amount of Si for the specimens containing more than 4 wt%Si. The other specimens of Ti-X (X=Cr, Mn, Cu) also showed the decreasing tendency of sintered density ratios with increasing amount of additional elements.
As the results of the tensile test concerning about Ti-2%Fe, Ti-2%Ni, Ti-2%Si and Ti-2%Co whose density ratios were more than 98%, it was confirmed that Ti-2%Fe specimen showed the highest value of tensile strength. Though the elongation value of 8% obtained for the (α+β)-quenched Ti-2%Fe specimen was much lower than 14% of the (α+β)-quenched Ti-2%Co specimen, it could be possibly improved by changing the heat treatment in (α+β)-region.抄録全体を表示PDF形式でダウンロード (6273K) -
真島 一彦, 平田 武彦, 山本 光政, 庄司 啓一郎1987 年 34 巻 5 号 p. 211-216
発行日: 1987/07/25
公開日: 2009/05/22
ジャーナル フリーStatic tensile properties of HIP'ed Ti-6A1-4V alloys after sintering at 1473 K for 3.6 ks by blended elemental powder metallurgy process were studied, and compared with those of HIP'ed Ti-6A1-4V powder compacts, made by Rotating Electrode Process (REP).
Metallographic and fractographic observations were also carried out by light and scanning electron microscopy, and X-ray energy dispersion analysis.
The tensile strength and ductility of HIP'ed Ti-6A1-4V alloy after sintering by blended elemental process using hydride-dehydride Kroll process sponge fines as the titanium source were clarified to be nearly the same as those of HIP'ed REP Ti-6A1-4V alloy. On the other hand, amarked ductility degradation was observed in the case of using Hunter process sponge fines as the titanium source, and it was confirmed that this behavior is closely related to the existing NaCI in the sintered compacts.抄録全体を表示PDF形式でダウンロード (7852K) -
小堀 景一, 植木 光生, 府川 敦, 鈴木 寿1987 年 34 巻 5 号 p. 217-221
発行日: 1987/07/25
公開日: 2009/05/22
ジャーナル フリーMechanical properties, cutting performance, etc., of WC-β(WC/TiC=70/30)-TaC-TiN-Co alloy (cobalt contents, 8-8.5%) sintered in vacuum and nitrogen (PN2=2.7 kPa) were studied as a function of TiN/(TaC+TiN) ratios (named TiN ratios).
The grain size of βt(WC-TiC-TaC-TiN solid solution) decreased with increasing TiN ratios and it naturally more decreased in sintering in N2, without change in the grain size of WC. The transverserupture strength, in particular, of HIP-treated alloy sharply increased with TiN ratios of more than 0.2. It was found that the resistance to oxidation of alloys was markedly improved with increasing TiN ratios.
The results of cutting tests showed that the fracturing and flank wear resistances were scarcely affected by TiN ratios, but the cutting performance of the alloy sintered in vacuum was always superior to that of the alloy sintered in N2.抄録全体を表示PDF形式でダウンロード (4092K) -
永井 宏, 沢山 哲也, 庄司 啓一郎1987 年 34 巻 5 号 p. 222-228
発行日: 1987/07/25
公開日: 2009/12/04
ジャーナル フリーThe effects of dispersion and superficial application of various rare earth oxides (Y2O3, La2O3, CeO2, Eu2O3, Gd2O3) on the isothermal oxidation of Fe-20Cr sintered alloy have been studied at 1373 K in air. The dispersion of these rare earth oxides reduced the oxidation rate but the effect on the oxidation rate was dependent on the kind of the dispersoid. That is, the dispersion of La2O3, Y2O3 and Gd2O3 greatly reduced the oxidation rate, while the effect of Eu2O3 dispersion was far less than that of the other rare earth oxides. The dispersion of rare earth oxides except for CeO2 suppressed the spalling of the scale. The superficial application of rare earth oxides except for Gd2O3 also markedly reduced the oxidation rate. The superficial application of Gd2O3 as well as Al2O3 had a negligible effect on the oxidation rate.
In the case of alloys which showed lower oxidation rate single layered Cr2O3 scale was maintained stably and the formation of Fe2O3 scale outside the Cr2O3 scale was suppressed; whereas thick Fe2O3 scale grew outside the Cr2O3 scale on the alloys which showed larger mass gain. The results suggested that the rare earth oxides which induced into the Cr2O3 scale suppressed outward migration of Fe ions through the Cr2O3 scale.抄録全体を表示PDF形式でダウンロード (3531K)
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