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Volume 36, Issue 3
Displaying 1-14 of 14 articles from this issue
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Hideaki Itoh, Akihiro Tsuzuki, Shigeharu Naka1989 Volume 36 Issue 3 Pages 259-266
Published: April 20, 1989
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSSintered compact of polycrystalline diamond was prepared by liquid phase (reaction) sintering which accompanies the transformation from graphitized carbon to diamond in the presence of solvent-catalyst. Sintering conditions were investigated at 7GPa and 1700°C in correlation with the effects of treatment parameters such as crystallinity of starting carbons, pretreatment of starting powders and composition of the solvent-catalyst. The addition of IVA transition metal (Ti or Zr) or diamond grains to the starting powder (graphitized carbon and catalytic active metal) is greatly effective on the depression of the grain growth and the homogenization of the microstructure of sintered compact. The transformation from graphite to diamond occurs in a short time, then followed by sintering of the formed diamond grains. The neck growth between the diamond grains and densification proceed by the solution and reprecipitation (liquid phase sintering) mechanism. The formation of a direct bonding of diamond-diamond grains results in the skeletal network of sintered diamond with the melt of carbon and solvent-catalyst metals pooled out.View full abstractDownload PDF (7045K) -
Osamu Kimura, Akira Chiba1989 Volume 36 Issue 3 Pages 267-271
Published: April 20, 1989
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSAs is well known, impurities contained in raw materials should be minimized for quality cotrol of ferrites. To attain this aim, iron oxide of high purity has been expected to become commercially available.
This paper describes a new method to prepare iron oxide of high purity from waste acid used for steel plate pickling, using a solvent extraction method. Firstly, ferrous ions contained in the acid are oxidized to ferric ions. Then, they are extracted into MIBK solvent. Chemical analysis shows that the extracted ferric solution is highly purified. The solution can be converted to iron oxide of high purity, using the spray roasting method which has been used to prepare iron oxide from the waste acid.
A trially produced iron oxide is found to contain very small amount of impurities, for instance, less than 20 ppm of SiO2.View full abstractDownload PDF (341K) -
Masaru Yokota, Hiroshi Nagai, Keiichiro Shoji1989 Volume 36 Issue 3 Pages 272-277
Published: April 20, 1989
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSDegrees of homogenization (H) of Cu-50 mass%Ni alloy powders produced by flame spraying technique were evaluated by adopting Rudman's method from X-ray diffraction profiles.
For producing flame sprayed alloys, Cu-50 mass%Ni mixed powder compacts with various Cu and Ni particle sizes were extruded after heating at 1023K for 600s to rods having 3.0mm diameter. Then, they were flame sprayed under a constant flame spraying condition.
Degrees of homogenization (H) of rods for flame spraying were estimated to be 0.249, 0.387 and 0.620 for 100-150, 200-250 and -350 mesh particle sizes of starting Cu and Ni powders, respectively. Whereas, H values of flame sprayed alloy powders were estimated to be 0.746, 0.805 and 0.838 for the same particle sizes as the above mentioned starting powders, respectively.
H values obtained from Rudman's method are commonly inclined to show lower values; H value of melted and then fully homogenized Cu-50 mass%Ni alloy was 0.898, smaller than unity. However, the Rudman's method is usefull on estimating the degree of homogenization quantitatively.View full abstractDownload PDF (2129K) -
Kazurou Nagashima, Yukiko Katatae, Akio Kato1989 Volume 36 Issue 3 Pages 278-283
Published: April 20, 1989
Released on J-STAGE: July 12, 2010
JOURNAL OPEN ACCESSConductive films were prepared from pastes containing Ag powders by the chemical flame method. Effects of size and dispersibility of the powders on thickness (L), texture, and sheet (RS) and specific (ρ) resistivity of the films were investigated. Very thin conductive films having low resistivity could be prepared from the present Ag powders; L=2.0-2.5μm, R5=11.6-18.1 mΩ/square, ρ=2.3-4.7μΩ⋅cm.View full abstractDownload PDF (4524K) -
Katsushi Takebe, Tadayuki Fujii1989 Volume 36 Issue 3 Pages 284-291
Published: April 20, 1989
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSIn order to obtain a large-scale bicrystal in sheet molybdenum by means of secondary recrystallization, the effects of rolling reductions and procedures on the secondary grain growth behavior were investigated texturally and optically.
It has been found that the development of secondary grain from both surfaces or a surface of sheet is strongly dependent on the rolling reductions. For the case of straight-rolled sheet having rolling reductions of 73%-93%, an abnormal grain growth from both surfaces occurred after an anneal at 1850°C and a large-scale bicrystal was obtained. In contrast, the abnormal grain growth from both surfaces occurred for the cross-rolled sheet having rolling reductions of 86%-93%.
These behaviours can be explained in relation to the texture gradients, and the shape and size of grains in the thickness direction obtained for primary recrystallized sheets as results of rolling reductions and procedures.View full abstractDownload PDF (7296K) -
Nobujiro Tsuchiya, Osamu Terada, Akira Sasaki, Hisashi Suzuki1989 Volume 36 Issue 3 Pages 292-295
Published: April 20, 1989
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe strength increase of green compact, that is, the higher compactibility of WC-Ni mixed powder made by ball-milling seems to be needed in the cemented carbide industry. Then, the study of the compactibility was carried out comparing with that of WC-Co powder. It was found that the compactibility of WC-Ni powder was generally lower than that of WC-Co one, when ball-milling condition was fixed, and that the phenomenon was caused by the fact that the size of binder-agglomerates formed during milling was larger in WC-Ni powder. Thus, refinning the agglomerates, for instance, by a prolonged ballmilling was necessary to improve the compactibility. The influence of agglomerates on the compactibility was discussed.View full abstractDownload PDF (3860K) -
Tsuguaki Ohki, Shoji Kanbe, Rikuo Ogawa, Nobuyasu Kawai1989 Volume 36 Issue 3 Pages 296-300
Published: April 20, 1989
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSChanges in the coercive force (Hc) of gas-atomized Nd-Fe-B powder were measured as functions of annealing temperature and particle size. The Hc of the powder (sieved to a particle size of <44 μm) increased with increasing annealing temperature, reached a maximum at 600°C and then decreased. In the Hc particle size dependence curves, the maximum levels of Hc of as atomized and annealed powders at 600°C were observed in the 60-90 μm and 10-20μm diameter size ranges, respectively. The 10-20 μm diameter powder annealed at 600°C for two hours exhibited an Hc of more than 10 KOe. The experimental results indicated that the Hc of Nd-Fe-B gas-atomized powder was dependent on strain and grain size as well as on the structure of the matrix phase and grain boundary.View full abstractDownload PDF (2000K) -
Yasuhiko Hashimoto, Koichiro Koyama, Kenji Suzuki, Atsushi Nanyoshi1989 Volume 36 Issue 3 Pages 301-305
Published: April 20, 1989
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSTo determine the solubility of C in δ-TiCxOy especially in the vicinity of the TiC1, 0 composition, the partial isothermal phase diagram of Ti-C-O system, indicating a high C side boundary of δ-TiCxOy phase in the low-oxygen region at 1473 K, was constructed from the chemical analyses of thoroughly equilibrated specimens which had been held for long time at various temperatures under various CO pressures, followed by vacuum heat-treatment (annealing) at 1473 K for 3 Ms.
The solubility of C in δ-TiCxOy was decreased markedly by the existence of small amounts of Oxygen especially in the cases of ≤0.7 at%O. When O≤0.02 at%, the solubility of C was ≥49.8 at%, and tended to increase toward 50 at% at the limiting condition of Oxygen→O%.View full abstractDownload PDF (387K) -
Yuji Katsumura, Mutsuo Asakawa, Tetsuya Mitsuda, Hisashi Suzuki1989 Volume 36 Issue 3 Pages 306-310
Published: April 20, 1989
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSIt was previously reported by the authors that the cutting performance of TiC, SiC and SiC whisker contained Al2O3 based black ceramics was quite unique and different in each other. Then the properties of combined ceramics having 25vol% of SiC and TiC were studied. It was found that the properties such as strength, resistance to oxidation, interfacial reaction between ceramics and work, and cutting performance for S48C and Inconel 600 were regularly changed according to SiC/TiC volume ratios. The reason was in the fact that, in combined black ceramics, SiC and TiC parTiCles coexisted in the structure, and mullite and Al2TiO5 also coexisted in the scale.View full abstractDownload PDF (2471K) -
Nobujiro Tsuchiya, Osamu Terada, Akira Sasaki, Hisashi Suzuki1989 Volume 36 Issue 3 Pages 311-314
Published: April 20, 1989
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe phase diagram of WC-Cr3C2-15 mass%Ni alloy was previously studied by the authors. The present study was undertaken to describe some properties such as mechanical properties, resistances to corrosion and oxidation, etc. of two-phase WC-Cr3C2-15 mass%Ni alloy in relation to Cr3C2 and carbon contents of the alloy.
It was found that the properties of two-phase alloy varied in a regular manner according to the Cr3C2 and carbon contents. For instance, transverse-rupture strength and hardness of the alloy increased with increasing Cr3C2 (up to 2-3 mass%) and decreasing carbon contents within the phase region. The resistance to corrosion in different solutions showed a strong dependency on the binder phase compositions.View full abstractDownload PDF (1533K) -
Mitsuo Ueki, Tsuyoshi Saito, Takeshi Saito, Hisashi Suzuki1989 Volume 36 Issue 3 Pages 315-319
Published: April 20, 1989
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSIt has been found out by the present authors that the amount of binder phase of TiC-Mo2C-Ni cermet containing nitrogen sintered in vacuum was often decreased in the region near the specimen surface. Then, the study was made to describe the reason why such a binder poor region (BPR) appeared in nitrogen added cermet. The TiC-10 vol%Mo2C-(0-40) vol%TiN-10 vol%Ni alloys with different carbon contents were in vacuum sintered at 1400°C for different times, and used as specimens.
The BPR with the thickness of about 500μm from the surface was generally observed, when the carbon and TiN contents in the cerinet were comparatively high and more than about 10 vol%, respectively. The BPR was also observed in the specimen, re-sintered after the surface region of firstly sintered specimen was ground off to remove BPR. The BPR formation was suggested to be caused by the fact that the region near the surface was carburized in contact with the sintering atmosphere, because denitrification during sintering process took place in the case of cermets with relatively high carbon; resulting in the surface region to be higher in the carbon content than the inside, which made Mo and Ti atoms diffuse out from inside to surface region.View full abstractDownload PDF (4369K) -
Nobujiro Tsuchiya, Osamu Terada, Akira Sasaki, Hisashi Suzuki1989 Volume 36 Issue 3 Pages 320-323
Published: April 20, 1989
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSThe WC-Ni alloy containing Cr3C2 has been widely used for non-magnetic or corrosion resisting parts. However, the (WC+γ) two-phase region of WC-Ni alloy affected by the Cr3C2 addition seems not to have been studied. The present work was concerned with this subject for WC-Cr3C2-15%Ni alloy. It was found that the two-phase and the adjacent (WC+γ+Cr3C2) three-phase regions shifted markedly to the high carbon side. It was also found that the solid solubility of Cr in the binder phase varied according to the carbon content of alloy and it showed a maximum value of about 16% for the alloy containing about 5.8%C.View full abstractDownload PDF (2795K) -
Nobujiro Tsuchiya, Osamu Terada, Minoru Saito, Hisashi Suzuki1989 Volume 36 Issue 3 Pages 324-329
Published: April 20, 1989
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSBy use of reduced and carburized starting powder with a composition of SKH57, and vanadium carbide (VC) powder, tool steels having higher VC content than that in SKH57 were vacuum-sintered, HIP-ed and finally heat-treated. The mechanical properties such as hardness and transverse-rupture strength (σm) at room temperature were studied in detail mainly as a function of vanadium (or VC) contents in the range from 3.5 to 18.5 mass%V.
The hardness and σm increased and decreased with increasing vanadium or VC content, respectively. As for the σm, it was found that the value of about 4.8 GPa of SKH57 dropped to that of 3.0 GPa, according to the increase in vanadium content from 3.5 to 18.5 mass%. It was noted that σm was controlled by the size of structural defect, that is, the segregated area of MC type carbides influenced mainly by the vanadium content, excepting the carbide structure, sintering and quenching temperatures, etc. The discussion as for the reason why such a structural defect as a fracture source develops in sintered tool steels, has been given.View full abstractDownload PDF (7376K) -
Takeshi Kaneko1989 Volume 36 Issue 3 Pages 330-336
Published: April 20, 1989
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSDynamic tensile properties of W-Ni-Fe alloys has been studied for a test temperature at 20°C and for a high strain rate using high speed impact tension testing machine of a constant speed type.
With this machine, high speed uniaxial tensile tests of the materials, 95.5W-3.0Ni-1.5Fe, 93.2W-4.5Ni-2.3Fe and 91.3W-5.8Ni-2.9Fe alloys, were carried out to obtain the relation between tensile strength and tensile speed in the range up to 15 m/s.
Also, the effect of circumferential notch having various notch root radii on the fracture behavior under dynamic tension was investigated.
Tensile strength and ductility of specimens were measured.
These experimental results seems to suggest that the dynamic tensile strength is larger than the static one.
The elongation also seems to be lower than static one with increasing tensile speed.
This seems to show the necessity to consider the factors such as the strain rate effect in stress strain relation, etc..
It was proved that fracture condition of these specimens can be explained, based on the comcept of "Linear Notch Mechanics".
Tensile fracture behavior of notch specimen is controlled approximately only by the values of notch root radius and ultimate tensile strength independently of the other dimensions of the specimen.
By considering these fracture textures, a fracture mode of specimens was proposed and the fracture mechanism was discussed.View full abstractDownload PDF (4074K)
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