巻号一覧
74 巻, 4 号
Powder Materials
選択された号の論文の9件中1～9を表示しています
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論説
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王 翠萍, 劉 興軍, 大沼 郁雄, 貝沼 亮介, 石田 清仁2003 年 74 巻 4 号 p. 221-226
発行日: 2003/10/15
公開日: 2010/03/23
ジャーナル フリーMicrostructure of Cu-Fe base alloy powders produced by conventional gas atomization was investigated and an egg-type core structure consisting of two or triple layers was obtained in the alloy systems which have a stable miscibility gap in the liquid phase. It was found that the minor liquid phase, which is dependent on the chemical composition of the alloy, always forms the core in a powder, assembling to the center of the powder. The origin of the formation of this core microstructure can be explained by Marangoni motion on the basis of the temperature dependence of the interfacial energy between the Fe- and Cu-rich liquid phases.
In principle, since the egg-type powder may be formed not only in alloy systems, but also in immiscible ceramics and polymer systems, it is expected for this new type of powder with the core structure to be utilized for various technical applications, such as electrical, chemical, magnetic parts, etc.抄録全体を表示PDF形式でダウンロード (256K) -
大河内 敬雄, 清水 孝純2003 年 74 巻 4 号 p. 227-232
発行日: 2003/10/15
公開日: 2010/03/23
ジャーナル フリーIt is difficult to produce gas-atomized Ti alloy powders with low oxygen content by using refractory crucible because of high activity of Ti with oxygen. Levitation melting with water-cooled crucible is promising method to obtain Ti alloy with low oxygen content. We have newly developed a gas atomization apparatus in combination with levitation melting furnace to produce Ti alloy powder with low oxygen. Ti-6Al-4V atomized powder with low oxygen was successfully produced by using the new apparatus; the oxygen content of the powder (0.06 mass%) was 7 ∼ 60 times lower than that of the powders atomized by using refractory crucibles.抄録全体を表示PDF形式でダウンロード (400K) -
長瀬 石根, 清水 孝純2003 年 74 巻 4 号 p. 233-239
発行日: 2003/10/15
公開日: 2010/03/23
ジャーナル フリーRecently, hydrogen absorbing alloys are used as the negative electrode of nickel-metal hydride secondary batteries, hydrogen storage of the polymer electrolyte fuel cells, and so on. An improvement of hydrogen-absorbing properties is required, because hydrogen storage capacity of the alloy is thought to be insufficient for the hydrogen storage use. In addition, the alloy is required to show small hysteresis factor and plain plateau slope in P-C-T curve for practical use.
Levitation melting, which is well-known for preparing way to obtain high purity alloys, is a promising method for the production of high performance hydrogen absorbing alloy, since the impurity such as the oxygen brings a deterioration of hydrogen absorbing properties. In this study, we have first tried the levitation melting method to prepare the hydrogen absorbing alloy. Ti-Cr-V alloys were successfully prepared by levitation melting method with special structural water-cooled cooper crucible. The characteristics of these alloys were investigated and the following results were obtained:
(1) Microstructure of the Ti-Cr-V alloy by levitation melting was more homogeneous than that prepared by arc-melting.
(2) The Ti-Cr-V alloys prepared by levitation melting contained lower impurity than those prepared with refractory crucible.
(3) The effective hydrogen storage capacity of Ti6.5Cr13V79Mn1.5 alloy by levitation melting was more than 2.1 mass%. Furthermore the plateau slope in P-C-T curve was very flat (0.16 Np/mass%), and hysteresis factor was very small (0.49 Np).
From the above results, the levitation melting method is thought to be suitable for the production method for hydrogen absorbing alloys with high performance.抄録全体を表示PDF形式でダウンロード (729K) -
武本 聡, 齊藤 貴伸2003 年 74 巻 4 号 p. 241-245
発行日: 2003/10/15
公開日: 2010/03/23
ジャーナル フリーCompressed cores made with soft magnetic alloy powders are widely used for smoothing and boost choke coils of switching regulators and DC-DC converters. Low core loss is required to be high performance of these compressed cores. In this study effects of particle size and crystal grain size on core loss of compressed cores with Fe-Si-Al atomized powders were investigated. Particle size and crystal grain size of powders were changed by water-atomization and heat treatment conditions. Compressed cores were made with these powders and obtained following results.
(1) Eddy current loss decreased with decreasing of the particle size, and hysteresis loss decreased with increasing of the crystal grain size of powders; the compressed core with small particle size and large crystal size showed low core loss.
(2) The compressed core with heat-treated fine powder (mean diameter = about 10μm) showed very low core loss (about 300kW/m3, at B=0.1T and f=100kHz).抄録全体を表示PDF形式でダウンロード (474K)
解説
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石井 啓, 筒井 唯之, 山西 祐司2003 年 74 巻 4 号 p. 247-258
発行日: 2003/10/15
公開日: 2010/03/23
ジャーナル フリーTechnology trends in sintered structural parts that account for 90% of all the powder metallurgical products produced by Hitachi Powdered Metals are introduced, focusing on materials and manufacturing technologies. The development of new sintered materials to meet the market's needs for higher strength, higher accuracy, cost reduction and manufacturing technologies such as warm compaction, die wall lubrication, multi-stepped compacting and sinter diffusion bonding that provide high density and complex shapes are outlined.抄録全体を表示PDF形式でダウンロード (1206K) -
五日市 剛2003 年 74 巻 4 号 p. 259-265
発行日: 2003/10/15
公開日: 2010/03/23
ジャーナル フリーHigh velocity flame spraying, such as HVOF and HVAF, with cermet spray powders has recently come into wide use in the petrochemical, paper, automotive and steel industries, in addition to being a chrome plate alternative. The dernier great advance in cost and quality of the hard dense coatings with exceptional wear and corrosion protection has magnetism for everyone concerned in the field of surface modification including thermal spraying. It has been found that powder particle strength and grain size of ceramics, as well as particle size distribution and manufacturing route of cermet powders, have a great influence on the deposit efficiency and the property of the coatings. Furthermore, we have made it clear that the proper choice of substrates with harder surface is vital for increasing separation resistance of the coatings containing carbides. These contemporary points of view can enhance the quality of cermet coatings, which lead to the further prevalence of cermet powders using high velocity flame spraying.抄録全体を表示PDF形式でダウンロード (424K)
技術資料
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松 康太郎2003 年 74 巻 4 号 p. 267-273
発行日: 2003/10/15
公開日: 2010/03/23
ジャーナル フリーTitanium and titanium alloys have been successfully used for many applications. On the other hand, joining is understood to be one of the most important processes involved in making products. Many joining processes have been established and employed in industrial fields. Of these processes, brazing in particular is useful for the joining complex or precision parts. In order to do brazing work, it requires not only to have knowledge of brazing technology, but also to be familiar with all properties of brazed materials itself. In this paper, it is explained about titanium and how to braze titanium.
Brazing titanium has been thought unreliable because there were no sufficient brazing filler metals that can successfully resist chloride attack. Prof. T. Onzawa developed titanium based brazing filler metals with low melting point in his prior study and these filler metals showed excellent in joint strength and corrosion resistance. We carefully investigated those filler metals and chose appropriate one for brazing heat exchanger. Then all titanium heat exchanger was made by brazing as one of the examples of titanium brazing work.抄録全体を表示PDF形式でダウンロード (351K) -
小川 典宏, 清水 成人, 武本 聡2003 年 74 巻 4 号 p. 275-278
発行日: 2003/10/15
公開日: 2010/03/23
ジャーナル フリーRecently, Fe-Si-Al alloy powder is widely applied for dust core in order to get high performance and miniaturization of magnetic parts. We have developed a new "oxygen-reducing process" for Fe-Si-Al alloy powder.
In this process, oxygen content of Fe-Si-Al alloy powder is reduced to 1/5 compared with conventional process. Therefore it is possible to prevent atomization trouble caused by growth of oxide at molten metal nozzle and cost of the powder production is reduced much lower. And core loss of the powder core is improved because of low oxygen content.抄録全体を表示PDF形式でダウンロード (242K) -
長谷川 健, 近藤 鉄也, 野田 正, 洞田 亮, 松本 隆, 大倉 幸雄2003 年 74 巻 4 号 p. 279-282
発行日: 2003/10/15
公開日: 2010/03/23
ジャーナル フリーWear resistant plate is widely applied in the field such as the iron and steel industry, the cement industry and so on. The plate is used under hard wear environment, so high wear resistance and long lifetime are required. We have developed wear resistant plate "E-PLATE" with excellent performance. "E-PLATE" is manufactured continuously and efficiently by "high-frequency induction fusing method" in which powder is used as raw material, and can be chosen various component of hardening layer by mixing of several powders.
It is confirmed that wear resistance depends on Vickers hardness of hardening layer.
Wear resistance of "E-PLATE" is better than one of conventional plate made by fusion welding. Especially, EH grade has superior wear resistance which is 10 times better than conventional plate. In addition, "E-PLATE" has high hardness at high temperature, so it can be applied under high temperature environment.抄録全体を表示PDF形式でダウンロード (230K)
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