巻号一覧
26 巻, 2 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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島田 昌彦, 石飛 裕1979 年 26 巻 2 号 p. 45-48
発行日: 1979/03/25
公開日: 2009/05/22
ジャーナル フリーPDF形式でダウンロード (269K) -
コバルト固溶酸化鉄の保磁力の経時変化と転写岸本 幹雄, 平田 純一, 端山 文忠1979 年 26 巻 2 号 p. 49-53
発行日: 1979/03/25
公開日: 2009/05/22
ジャーナル フリーThe variation of coercivity in annealing at 60°C and the printing effect of cobalt-substituted iron oxides with various contents of Fe2+ were examined. Except the samples containing Fe2+ less than 1 wt% the coercivity increased with annealing at 60°C, and the samples containing more Fe2+ showed higher coercivity. The increase of coercivity was attributed to the magnetic anisotropy induced in cobalt-substituted iron oxides by the spontaneous magnetic field of shape anisotropy. The existence of Fe2+ was considered to facilitate the migration of CO2+. The printing effect of cobalt-substituted iron oxides decreased with an increase of the annealing period at 60°C. The increase of Fe2+ content in samples resulted in the increase of printing effect. This printing effect was explained by the magnetic anisotropy induced in the direction of printing field.抄録全体を表示PDF形式でダウンロード (356K) -
大野 英治, 筑後 和男, 花井 圭介1979 年 26 巻 2 号 p. 54-59
発行日: 1979/03/25
公開日: 2009/05/22
ジャーナル フリーThe as-atomized steel powders containing Mn and Cr were coated with phenol resin. Then, the powders were compacted and sintered in N2 atmosphere. Oxides in the surface layer of the atomized powders were actively reduced and the required carbon contents were obtained with residual carbon after decomposition of resin. The results were summarized as follows:
(1) In the low alloy steel powders of Mn, Cr series which are more difficult to be reduced than that of Ni, Mo series, the amount of residual oxygen could be decreased from 7200 p.p.m. to 200 p.p.m. through the reduction sintering at 1200°C for 120 min.
(2) The as-atomized steel powders were coated with thermosetting phenol resins. The phenol resin has many effects such as lubricating and binding between the powders at compacting, and reducing the oxygen and adding the carbon at sintering.
(3) In the as-atomized steel powders, it is desirable that the contents of Al and Si being difficult to be reduced and the amount of oxides to be mixed in the melting process must be decreased. The oxygen content desired is less than 10000 p.p.m. and the carbon content is less than 0.1 %.
(4) The optimum amount of phenol resin is from 2.0% to 3.5% to maintain the strength of green compaction and prevent cracking at the sintering.抄録全体を表示PDF形式でダウンロード (2739K) -
三浦 秀士, 徳永 洋一1979 年 26 巻 2 号 p. 60-65
発行日: 1979/03/25
公開日: 2009/05/22
ジャーナル フリーYoung's modulus of sintered iron was measured by a composite piezo-electric quartz oscillator, which is one of the dynamic resonance means. This method gives better accuracy and reproducibility as compared with the mechanical bending test. Specimens (4×4×40 mm) were prepared from a carbonyl iron powder and various commercial iron powders, followed by compacting under 2-9 t/cm2, presintering for 20 min at 650°C and sintering for 0.1-30 hrs, at 800-1200°C in hydrogen.
The results obtained are summarized as follows:
Young's modulus of sintered iron, in general, increases with an increase of the density. Comparing specimens with the same density, Young's modulus of the Carbonyl sintered iron is considerably higher than that of the commercial sintered irons. The reason for this can be attributed to the existence of irregular pores in the commercial one.
Young's moduli of the specimens sintered at austenitic temperature are appreciably higher than those of the specimens with the same density, but sintered at ferritic temperature.抄録全体を表示PDF形式でダウンロード (5240K) -
斉藤 総一郎, 岡田 元秀, 山口 喬1979 年 26 巻 2 号 p. 66-71
発行日: 1979/03/25
公開日: 2009/05/22
ジャーナル フリーEffect of Mn content on the interaction between liquid Cu-Mn alloys containing from 17.7 to 61.1 wt% Mn and WC-8%Co alloys have been studied between 955°C and 1100°C. The diffusion layers formed between both alloys are analysed by means of EPMA, optical microscopy and microhardness measurement.
The structures of diffusion layers are tentatively classified into four types depending on the heating temperature and Mn content of the Cu-Mn alloy. Heating near the liquidus temperature of the Cu-Mn binary system yields additional carbide-free layer in the cemented carbide. However at 1100°C, a lower carbide η phase forms in the cemented carbide. The structures of diffusion layers are influenced markedly by cobalt content and WC grain size of the cemented carbide but not significantly by the carbon content. These results are discussed referring to the previous results on the interaction between pure Cu and cemented carbides.抄録全体を表示PDF形式でダウンロード (3948K) -
三宅 雅也, 原 昭夫1979 年 26 巻 2 号 p. 72-77
発行日: 1979/03/25
公開日: 2009/12/04
ジャーナル フリーA severe control of carbon content is needed for the direct production of WC from WO3. In order to solve this problem for an industrial scale, a rotary carburization furnace for high temperatures was developed. This furnace comprises a rod-shaped heater of graphite in the center of the furnace and a rotating cylinder of graphite positioned coaxially around this heater. The inner wall of rotating cylinder is heated indirectly by means of supplying electric power to the graphite heater.
The mixed powder of WO3 and carbon was granulated and the resulting granules were continuously fed into the furnace which was kept at 1150°C-1650°C.
WO3 was sufficiently reduced and carburized by carbon in this furnace. The gases formed during reaction in the rotary furnace were CO and CO2, and the ratio PCO2/PCO corresponded to the carbon content of the carburized product.
It became clear from these results that the carbon content can be controlled by the ratio PCO2/PCO which is subject to the operating conditions of the rotary furnace.抄録全体を表示PDF形式でダウンロード (2829K)
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