巻号一覧
38 巻, 4 号
選択された号の論文の16件中1～16を表示しています
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横田 勝1991 年 38 巻 4 号 p. 464-471
発行日: 1991/06/25
公開日: 2009/05/22
ジャーナル フリーFirst of all, a study for the infiltration mechanism was carried out; a general differential equation and the rigid solution for the penetration of liquids into porous bodies have been derived. For confirming the validity of mathematical solution, penetration experiments of both pure water and aqueous sulphuric acids into sintered bodies of glass powder have been carried out, From the comparison of theoretical considerations with experimental results it was confirmed that the rigid solution obtained from this study was effective for the penetration of liquids into porous bodies.
On the other hand, for the case of liquid metals and metal skeletons, for example, an infiltration of liquid Sn-Cu alloys against sintered bodies of Cu powder, some distinctions between theoretical values and experimental values were detected especially at a late stage of the infiltration process, in spite of considering reactions between liquid and solid layers and time dependency of wetting angle. Further investigation is required to give a full account of the infiltration phenomenon, especially by considering the structural alterations of pores in skeletons during infiltration process.
Experiments of applied techniques of infiltration were carried out for Cu-Fe and Pb-Fe systems. For the Cu-Fe system, influences of infiltration time, addition of alloying elements to Cu infiltrant and heat treatments after infiltration on mechanical properties were examined. For the Pb-Fe system, the wettability of liquid Pb and Pb alloys to Fe plates, and damping characteristics and mechanical properties of Fe sintered compacts, infiltrated with Pb or Pb alloys were examined.抄録全体を表示PDF形式でダウンロード (1672K) -
マトリックスの影響安斎 正博, 真崎 浩一, 中川 威雄1991 年 38 巻 4 号 p. 472-476
発行日: 1991/06/25
公開日: 2009/05/22
ジャーナル フリーMagnetic abrasive polishing process was experimentally tried to finish the mold surface. Magnetic abrasives are playing a very important role in this process. NbC-Fe magnetic abrasives were newly produced by Plasma Powder Melting (PPM) Method. This study aims to investigate the relationship between Fe matrix and the grindability of PPM magnetic abrasives. The carbon content range of maximum bending modulus of Fe matrix was 0.4 to 0.6 Wt%. The maximum grindability of NbC-Fe magnetic abrasive was obtained in the carbon content range of 0.4 to 0.6 Wt%. These carbon contents range agree with each other precisely and the results suggest that there exists an adequate correlation between the elasticity of Fe-matrix and the grindability of PPM magnetic abrasives. It is possible to fabricate high grindability magnetic abrasives using more elastic Fe-matrix like alloy steel. In order to increase the removal rate, it is nesessary to investigate the influence of Fe-matrix conditions in more detail.抄録全体を表示PDF形式でダウンロード (4778K) -
山元 洋, 小野 輝久1991 年 38 巻 4 号 p. 477-481
発行日: 1991/06/25
公開日: 2009/12/04
ジャーナル フリーAn experiment was carried out to investigate the effect of addition of composite rare-earth oxide (55La2O3-34Nd2O3-10Pr6O11) on magnetic properties of isotropic BaO⋅6Fe2O3 magnets. It was found that the magnetoplumbite structure was stabilized by addition of composite rare-earth oxide to BaO⋅6Fe2O3 compound. These Ba-La-Nd-Pr system ferrites had excellent properties as a isotropic parmanent magnet, and the value of (BH)max at the condition semisintered at 1000°C was equivalent to those of ordinary isotropic Ba and Sr ferrites, The optimum conditions of making an isotropic magnet and some properties of typical sample are as follows; a) composition: BaO⋅6Fe2O3 in addition with 2 wt% composite rare-earth oxide, b) semisintering condition: 1200°C×1h in O2 gas and sintering condition: 1350°C×0.5h in O2 gas, c) magnetic properties: Jm =0.395T, Jr=0.265 T, HcJ=184 kA/m, HcB=162 kA/m, (BH)max=11.8 kJ/m3, Tc=451°C, D=5.16 Mg/m3.抄録全体を表示PDF形式でダウンロード (1246K) -
藤内 秀人, 林 宏爾1991 年 38 巻 4 号 p. 482-485
発行日: 1991/06/25
公開日: 2009/05/22
ジャーナル フリーThe hot-pressing condition for complete densification of Co+Ni and Fe+Co+Ni mixed ultrafine powders (0.02μm), the average crystal grain size and hardness (Hv) of the sintered compacts were investigated, compared with the previous results on Fe, Co, Ni, Fe+Co and Fe+Ni ultrafine powders.
The results obtained were as follows: (1) The lowest complete densification temperatures for Fe+Co+Ni mixed powder, for example at 400 MPa, was about 200-300 K higher than those of Fe, Co and Ni powders, and about 100K higher than Co+Ni, Fe+Co and Fe+Ni powders. (2) The minimum crystal grain size of the Co-Ni and Fe-Co-Ni sintered compacts were 0.18 and 0.12μm respectively; the crystal grain size under the same hot-pressing condition tended to decrease with the number of components, in accordance with the tendencies of both the homogenization temperature of the components and the densification temperature. (3) The maximum hard-ness of Co-Ni and Fe-Co-Ni sintered compact were about 600 and 800 Hv.抄録全体を表示PDF形式でダウンロード (1478K) -
平石 久志, 小林 俊郎1991 年 38 巻 4 号 p. 486-491
発行日: 1991/06/25
公開日: 2009/05/22
ジャーナル フリーThe objective of the present study is to make an investigation on fabrication condition of Cr3C2-Co base alloy composite by arc energy melting, and on the characteristics. That is, this paper deals with the investigation in (1) the effects of Cr3C2 content, preheat temperature and wall thickness (fixing the base metal during fabrication of the composite) on the crack sensitivity in a Cr3C2-Co base alloy composite metal, (2) the effect of Cr3C2 content on strengthening the matrix alloy and (3) the microstructure or the hardness in the composite metal.
The results obtained are as follows:
(1) Thickness of deposition layers hardened becomes thinner with increasing in Cr3C2 content and also demands higher preheat temperature.
(2) Co base alloy is markedly strengthened by the addition of Cr3C2 and shows a peak in the strength of 107.3 kgf/mm2 with high ductility at 20% of Cr3C2. But the increment of Cr3C2 above 20% leads to the decrement of the strength due to the growth of needle structure of Cr3C2.
(3) In the fabrication, it should be taken a consideration on the diffusion of the composite element at boundaries in the matrix metal.抄録全体を表示PDF形式でダウンロード (1521K) -
坂本 卓1991 年 38 巻 4 号 p. 492-498
発行日: 1991/06/25
公開日: 2009/05/22
ジャーナル フリーThe effects of boronizing conditions in sintered Mo-Ni powder compact were investigated, which was treated with the mixed powders; MoB, B4C, NiB as a B element supply and NH4Cl, BaF2, Na2CO3 in activitor.
The results obtained were as follows;
(1) The thickness of boride layer of all specimens increased with increasing boronizing temperature and time.
(2) Line analysis patterns of the EPMA showed that the boride layers in sintered Mo-Ni powder compacts were clearly recognized in the cases of MoB and B4C powders.
(3) The X-ray diffraction showed that the boride layers of sintered Mo powder compacts consisted of three phases of MoB, Mo2B and Mo2B5.
(4) Effect of activitors showed that the existence of each phase of MoF3 and of MoCl2 was recognized by the X-ray diffraction, when using the NH4Cl and BaF2 in activitors.
(5) NiB powder tested in B element supply was not suitable to increase the thickness of boride layer.抄録全体を表示PDF形式でダウンロード (3710K) -
寺田 修, 土屋 信次郎, 佐々木 章, 鈴木 寿1991 年 38 巻 4 号 p. 499-504
発行日: 1991/06/25
公開日: 2009/05/22
ジャーナル フリーIt has been known that white spots frequently appear in SEM structure of titanium carbide (TiC) grains in nitrogen contained TiC based cermets. The formation of the white spots was studied as functions of alloy system, alloy composition and sintering conditions, using specimens having coarse TiC grains in the structure.It was found that the white spots appeared only in TiC-TiN (or Ti(C, N))-Mo2C-Ni alloy system, and the formation of white spots varied according to the above factors. It was assumed in TiC-TiN-Mo2C-Ni alloy system that TiC grains did not easily dissolve in liquid binder at the sintering temperature, because molybdenum atoms tended to diffuse in TiC grains to form TiC-Mo2C solid solution. Consequently, TiC grains had to dissolve with making many slits around the periphery of TiC grain, resulting in the liquid-infiltration in the slits and the formation of white spots.抄録全体を表示PDF形式でダウンロード (4705K) -
土屋 信次郎, 福田 雅秀, 中井 毅, 鈴木 壽1991 年 38 巻 4 号 p. 505-509
発行日: 1991/06/25
公開日: 2009/05/22
ジャーナル フリーThe transverse-rupture strength of WC-(10, 20)%Co alloys oxidized in air at the temperature of 973-1173 K for the time of 0.3-1.8 ks was studied as a function of Co content, carbon content of alloys, WC grain size and r-domain size. It was found that the strength of the alloy decreased owing to the surface oxidation and the strength decrease became larger with rising temperature and increasing time. It was noted that the strength decrease was enhanced with increasing r-domain size. It was also found that the rate of oxidation was faster in the domain boundary than inside the domain, so that the domain boundary after oxidation acted as a notch during transverse-rupture test, leading to the strength decrease.抄録全体を表示PDF形式でダウンロード (2353K) -
Hisashi Hiraishi, Mituru Furukawa, Toshiro Kobayashi1991 年 38 巻 4 号 p. 510-515
発行日: 1991/06/25
公開日: 2009/05/22
ジャーナル フリーThe effect of relative density on a compressive deformation rate in chromium carbide composite (Cr3C2+Cr7C3) and the reliability in the strength was investigated. A chromium carbide sintered compact with a carbon content of 13.1wt% was fabricated from the high purity Cr3C2 powder with a particle size below 1μm. After being presintered at 1673-1773 K for 3000 sunder a vacuum of 0.13 Pa, the green compact was pressed isostatically at 150 MPa at 1623K for 3600s. The deformation rate in the composite with a lower relative density increases under a high compressive strength at an elevated temperature. But that with a higher relative density above 98% is hardly influenced by a stress. A HIP process is significantly effective in increasing in the density of the composite. The composite with a Weible parameter of 16.8 can be produced with a deflection of±15% in 2S/σm by the HIP.抄録全体を表示PDF形式でダウンロード (4825K) -
蜂須賀 武治1991 年 38 巻 4 号 p. 516-522
発行日: 1991/06/25
公開日: 2009/05/22
ジャーナル フリーThe study was attempted to reason the superiority of TiC-Cr3C2 based multi-component ceramic composites, which have been toughened by multi-toughening mechanism comprising branching and deflection of cracks and micro-cracking, in regard to tool life in intermittent cutting. On the bases of their mechanical properties of various cutting tool materials, the fracture resistance was discussed.
It was clarified that the superior tool life of the ceramic composites could be understood according to the large value of "thermal shock damage resistance parameter", proposed by D. P. H. Hasselman. It means that it is essential for substantial improvement of fracture resistance in ceramic tools to take place R-curve behaviour at fracture.
The possibility of toughening in liquid phase sintering alloys for cutting tool in the same mechanism as the ceramic composites was also clarified in the study.抄録全体を表示PDF形式でダウンロード (469K) -
津田 正夫, 京極 秀樹1991 年 38 巻 4 号 p. 523-528
発行日: 1991/06/25
公開日: 2009/05/22
ジャーナル フリーThe effect of sintering conditions on the mechanical properties of SUS304L stainless steel sintered powder made by injection moldings has been studied. Specimens were made of SUS304L with 9μm in average diameter which was sintered at temperatures of 1573 K to 1673 K with the holding period of 1.8 ks to 14.4 ks in vacua of 1 Pa, then they were cooled in evacuated or nitrogen gas atmosphere. The higher the sintering temperature, and the longer the holding period at the elevated temperature, the greater the density of the sintered specimen. An example of this was greater than 98%. Specimens cooled in vacua gave the tensile strength of 520 MPa and the maximum hardness was given at the sintering temperature of 1623 K, regardless of the holding period. The mechanical strength of a sintered SUS304L specimen cooled in vacua was comparable with a specimen which was melted and cast. The specimens cooled in nitrogen gas yielded higher strengths and hardnesses possibly due to the nitride formation on the surface.抄録全体を表示PDF形式でダウンロード (5264K) -
鎌田 政智, 山中 雅樹, 徳永 洋一1991 年 38 巻 4 号 p. 529-534
発行日: 1991/06/25
公開日: 2009/05/22
ジャーナル フリーEffect of boride powder (FeB, CrB and NiB) addition on the densification of SUS304L (Fe-18 wt%Cr-11wt%Ni) powder compacts are investigated in relation to liquid phase sintering. The mechanism of liquid phase formation and sintering process are mainly discussed for the case of CrB addition. The results are summarized as follows:
CrB powders added to SUS304L compacts change to Cr2B during heating for sintering and a eutectic reaction occurs between the Cr2B and the matrix to form liquid phase. Liquid phase formed through the eutectic reaction permeates among SUS304L powders and this results in disappearance of small pores finely dispersed in the matrix and formation of large pores at spots where CrB powders have originally situated. Densification of the compacts is greatly promoted because of the liquid phase which remains during sintering. The liquid phase finally solidifys to the mixed structure of austenite and Cr2B on cooling. Almost the same results are also obtained for FeB or NiB addition.抄録全体を表示PDF形式でダウンロード (4943K) -
鎌田 政智, 徳永 洋一1991 年 38 巻 4 号 p. 535-539
発行日: 1991/06/25
公開日: 2009/05/22
ジャーナル フリーSUS410L (Fe-12 wt%Cr) and graphite mixed powder compacts are sintered at 1473 K to 1598 K, followed by heat treatment for controlling the matrix microstructure to martensite. The effects of carbon content on the sintering behavior and tensile properties are discussed, in order to develop the high strength P/M martensitic stainless steels. The results are summarized as follows:
The amount of δ-ferrite at sintering temperature decreases and that of austenite increases with increase in carbon content and decrease in temperature. Specimens containing much amount of δ-ferrite undergo densification and pore-rounding during sintering, because of high self-diffusibility of δ-ferrite.
0.1 wt% of carbon is necessary at least in order to control the matrix microstructure to martensite through optimum solution treatment.
Tensile strength of low temperature tempered specimens increases with increasing carbon content as well as advance in densification. The latter method might be better for strengthening the specimens in view of corrosion resistance.抄録全体を表示PDF形式でダウンロード (3947K) -
金子 武1991 年 38 巻 4 号 p. 540-547
発行日: 1991/06/25
公開日: 2009/05/22
ジャーナル フリーThis report describes the results of investigations on the improvement mechanical properties of W-Ni-Fe heavy alloys which were produced with optimum Ni/Fe ratio and addition of suitable amount of Co to basic composition of W-Ni-Fe.
These alloys are produced by liquid phase sintering of mixed elemental Ni and Fe powder in a ratio region 1 : 1-10 : 1 with addition of Co content of about 0.5 and 1.0 wt%.
The strength and ductility at room temperature of the heavy alloys attained a maximum with Co content of about 0.5 wt% with the Ni/Fe ratio of about 4.0.
These results were discussed in terms of microstructures, size of fracture source, toughness of matrix, etc.抄録全体を表示PDF形式でダウンロード (2222K) -
和田 重孝, 渡辺 直義1991 年 38 巻 4 号 p. 548-551
発行日: 1991/06/25
公開日: 2009/05/22
ジャーナル フリーThe effect of the fracture toughness of impact particles on the erosive wear of ceramics was examined. Six kinds of Al2O3 abrasive particles, which were almost the same in size, figure and hardness, but only different in fracture toughness were used as impact particles. Sintered Si3N4, Al2O3 (HA90) and glass were used as target materials. Irrespective of the target materials, the erosive wear rate was qualitatively proportional to the fracture toughness of the impact particles.抄録全体を表示PDF形式でダウンロード (253K) -
井川 良雄, 熊谷 憲1991 年 38 巻 4 号 p. 552-556
発行日: 1991/06/25
公開日: 2009/05/22
ジャーナル フリーThe Osprey Process introduced here is a kind of spray deposition, available for manufacturing bulk preform of high density and high strength by one process straight from molten metals.
The characteristics of this osprey preform are as follows;
(1) Osprey preform density as deposit is higher than 99.4% for high speed steel (Disc preform) and higher than 99.3% for high carbon high speed steel (Tube preform).
(2) The transverse rupture strength of Osprey preform after forged is superior to that of wrought alloy.
(3) The transverse rupture strength of Osprey preform after HIP treatment is 2 times as high as that of conventional cast.
(4) The density and strength of Osprey preform which were adequately deposited, worked and heat treated are expected to be improved further.抄録全体を表示PDF形式でダウンロード (3696K)
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