All issues
Volume 49, Issue 9
Displaying 1-15 of 15 articles from this issue
- |<
- <
- 1
- >
- >|
-
Osamu Iwatsu2002 Volume 49 Issue 9 Pages 759-764
Published: September 15, 2002
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe three manufacture engineerings on copper and copper based alloyed powders for powder metallurgy have been developed. The powders manufactured by these methods were as follows.
1) The partially alloyed copper powder can be manufactured by only the simple heat treatment after mixing. And this powder has the properties as nearly good in compactibility and sinterability as mixed powders and less in segregation.
2) By applying the stable condition of the water jet, Cu-Sn, Cu-Zn, Cu-Co and Cu-Sn-Pb-Zn alloys were atomized and the obtained powders have compactibility of 1.5-2.0 times higher than that of powders produced under the conventional condition.
3) The spherical finer powder was manufactured by the newly developed high-pressure water atomization method using swirl water jet. Cu-Sn alloy was atomized by this method. The median diameter of this powder decreased from 12.5μm to 7.5μm with increasing swirl degree.View full abstractDownload PDF (428K) -
Motohiro Miyasaka, Tadashi Momono2002 Volume 49 Issue 9 Pages 765-772
Published: September 15, 2002
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe microstructure of tin additions, the bearing materials of solid lubricant additions, interface pressure and velocity were examined for their influence on the run-in of bronze-based oil-impregnated sintered bearings. The run-in-time increased in accordance with the increase in the apparent hardness. When the apparent hardness was equal, the run-in-time was shorter when it had obtained a more heterogeneous microstructure with some intermediate phase than a homogeneous Cu-Sn solid solution. Moreover, the solid lubricant content increased as the run-in-time decreased. When the interface pressure increased the run-in-time became shorter. On the other hand, when the velocity increased the run-in-time became shorter.View full abstractDownload PDF (6109K) -
Tadahiro Wada, Takaomi Toihara2002 Volume 49 Issue 9 Pages 773-779
Published: September 15, 2002
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSThe tool life in turning of the sintered steels becomes shorter than that in turning of the melted steels such as carbon steels. In order to clarify the effect of the sintered elements in CBN tool on the cutting performance, the sintered steel was turned with the various CBN tools which have the different contents of the cBN grain and the different binding phase, at the cutting speed 5.0 m/s, the feed rate 0.05 mm/rev and the depth of cut 0.1 mm. The tool wear and the surface roughness were experimentally investigated.
The main results obtained are as follows:
(1) The wear progress of the CBN tool which has the TiN based binder is slowest.
(2) In the CBN tools, the tool wear decreases with the increase of the cBN grain contents.
(3) The surface roughness of the CBN tool which has the TiN based binder is smaller than that of the CBN tools which have the TiC, or Al2O3 based binder. Therefore, the CBN tool which has the TiN based binder is the most effective tool material for the turning of the sintered steel.View full abstractDownload PDF (5980K) -
Kaduichi Kitagawa, Takeshi Toyoda, Kazuo Kitagawa, Takashi Yamamoto2002 Volume 49 Issue 9 Pages 780-786
Published: September 15, 2002
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSFabrication conditions, piezoelectrical and mechanical properties of lead-free (Bi1/2Na1/2)TiO3 (BNT) doped PZT ceramics were investigated. For BNT as additives, decarbon dioxide of starting materials terminated to 700°C. Crystallization of BNT was induced above 600°C. The crystal phase of the sintered BNT ceramics was rhombohedral (a=3.885Å, a=90.003°). The secondary phase of Bi2TiO7 was formed by adding excess Na2O. Additon of excess Na2O promoted the sintering of BNT. For BNT doped PZT, the electromechanical coupling factor (kp) value was maintained at 60-70% of PZT with 0.5 and 1.0% BNT. The four point bending strength of BNT doped PZT specimens with 0.5 and 1.0 wt%BNT addition sintered at 1150°C was increased. The maximum value of Weibull modulus was 9.5.View full abstractDownload PDF (4614K) -
Kiyotaka Kato, Takami Masui2002 Volume 49 Issue 9 Pages 787-792
Published: September 15, 2002
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSFor the injection molded FeAl intermatallic compounds (Fe-45Al and Fe-48A (at.%)), 0.5 at.% boron (B) powder was added to FeAl powders in order to improve the mechnical properties of sintered compacts, and the tensile properties were examined in air at room temperature, 400°C and 600°C. The results obtained were summerized as follows: (1) Boron acted as sintering aids, so its addition contributed to decreasing the sintering temperature of FeAl. (2) At room temperature, the sintered Fe-45Al compact showed a little changes on the tensile properties by boron addition. On the other hand, the elongation of sintered Fe-48Al compact was improved to 1.0% to 0.3% by boron addition. (3) At high temperature, especially at 600°C, boron addition was effective for the improvement of both 0.2% proof stress and tensile strength of sintered compacts.View full abstractDownload PDF (5428K) -
Nobuhiro Sadatomi, Naoya Hamamoto, Tsunekazu Saigo, Osamu Yamashita2002 Volume 49 Issue 9 Pages 793-798
Published: September 15, 2002
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSRecently heat spreader becomes more important for the heat diffusion of a micro processor unit (MPU). Physically, it needs a material with both low thermal expansion a and high thermal conductivity K. Although Cu-W, AIN and Al-SiC have hitherto been studied exhaustively as materials suitable for application in various heat spreaders, these materials have been limited to special uses because of a high price resulting from the complicated fabrication processes. Until now the study of heat spreader has hardly been made on Al-Si system, because this material tends to become more brittle and to make the fabrication more difficult as Si content increases, particularly in the composition range available for heat spreaders. Although there are such troublesome problems in Al-Si, we investigated both thermal conductivity K and thermal expansion a of Al-Si materials prepared by the conventional casting method. As a result, the Al-50Si material was found to have values of K = 150 W/m ⋅K and a =10 x10-6/K, respectively, which satisfy the thermal characterization required for heat spreaders. However the brittle Si phase in Al-50Si was needled to a length of about 0.5 mm, resulting in a marked lowering of tenacity. For this reason, the die casting method was employed to control the grain size, so that so precipitated Si phases became smaller needles of a length of approximately 30μm, leading to the effective improvement of tenacity.View full abstractDownload PDF (3950K) -
Yuki Yoneda, Nobuya Machida, Toshihiko Shigematsu2002 Volume 49 Issue 9 Pages 799-806
Published: September 15, 2002
Released on J-STAGE: July 12, 2010
JOURNAL FREE ACCESSLithium-ion-conducting amorphous materials in the system LiI-Li2S-SiS2 were prepared by use of high-energy ball-milling methods at room temperature. Crystalline LiI, Li2S, and SiS2 reagents were used as raw materials for the sample preparation. The amorphous materials were obtained in the composition range of x = 0 to x = 30 in xLiI⋅(100-x)(0.6Li2S ⋅0.4SiS2) and xLiI⋅(100-x)(0.5Li2S ⋅0.5SiS2) (mol%) notations. The obtained amorphous materials showed high lithium ion conductivities in the range of 1 x 10-4 to 7 x 10-4 Scm-1at room temperature depending on their compositions. The conductivity increased with an increase in the LiI contents. The transport number of Li+ ions was almost unity for the obtained amorphous materials.View full abstractDownload PDF (653K) -
Junjiro Takekawa2002 Volume 49 Issue 9 Pages 807-811
Published: September 15, 2002
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSIt has been known B is the most effective sintering enhancer for stainless steel powders. But at the same time, a considerable grain growth was often seen in the sintered compacts containing B. In order to obtain the sintered compacts with high densities and fine-grain structures, 0.2-1.4 mass%Al2O3 fine powders were mixed with SUS316L water atomized steel powder, in addition to 0.4 mass% B powders. These mixed powders were compacted and sintered in H2 atmosphere at 1232-1252°C for 1 hr.
It was shown that the SUS316L steel powder compacts were much more densified during sintering when Al2O3 fine powders were added together with B powders, compared with when B powders alone were added. It was considered Al2O3 fine powders prevented the formation of isolated large pores which tended to emerge during sintering of SUS316L steel powders containing only B powders, and resulted in the high densification. It was also shown that the tensile strengths of the sintered compacts were fairly improved by the addition of Al2O3 fine powders because of its function making the grains finer. The reduction of the elongation causing by the addition of Al2O3 fine powders was in allowable ranges.View full abstractDownload PDF (5321K) -
Kazuo Kato, Michihiro Tagami, Shinji Yamada, Tohru Takeda2002 Volume 49 Issue 9 Pages 812-817
Published: September 15, 2002
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSIn order to develop Graphite dispersed sintered bronze bearing material standing in the use of a higher load application, effects of Cr addition on sintering properties and microstructures of the bronze matrix were investigated. Mixed powders were prepared from elemental Cr powders and atomized 90Cu-10Sn powders, of which particle sizes were 106-50μm and 1-38μm, respectively. Compacts pressed at 390 MPa were sintered at 670-1030 K for 0.3-180 ks in H2. With increasing sintering time at 1030 K, pores decrease rapidly with the refinement of grain size in the bronze matrix surrounding Cr particle. This indicates that the densification of the bronze is promoted by the diffusion of Cr.View full abstractDownload PDF (6334K) -
[in Japanese]2002 Volume 49 Issue 9 Pages 820
Published: September 15, 2002
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSDownload PDF (115K) -
Yoshiyuki Kato2002 Volume 49 Issue 9 Pages 821-824
Published: September 15, 2002
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSIt is said that there are more than 40 MIM (Metal Injection Molding)-related companies in America. Aiming at the diffusion of MIM, 21 of these companies have formed and are members of an organization called MIMA (Metal Injection Molding Association). MIMA is one of the lower branches of MPIF (Metal Powder Industries Federation). Among MIMA member companies, there are MIM parts producers; powders, binders and feedstock suppliers; and MIM machine, debinding and sintering equipment suppliers. Last year, MIMA sent out a questionnaire to each of its member companies to inquire into the present conditions and future prospects of the MIM business, problems that hinder the diffusion of MIM, measures to be taken in order to achieve diffusion, etc. The results, which were totaled and released to member companies last year in October, indicated that most of the companies believed that a lack of educational campaigns aimed at part designers, who are MIM customers, was impeding MIM diffusion. At present, since it is also believed in Japan that the achievement of diffusion of MIM technology depends on the improvement of the understanding level of part designers, JSPM (Japan Society of Powder and Powder Metallurgy) and JPMA (Japan Powder Metallurgy Association) have begun to take measures aiming at MIM standardization and educational campaigns. We have the impression that the problems confronting MIM are the same around the world. The findings of this survey provide very interesting hints, and we believe that they will be a good reference for the development of MIM technology in our country.View full abstractDownload PDF (553K) -
Hideshi Miura, Takanori Masuda, Tadashi Ogasawara, Yoshimitsu Kankawa2002 Volume 49 Issue 9 Pages 825-828
Published: September 15, 2002
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSIn this study, the metal injection molding process for high performance Ti compacts were investigated. Low oxygen gas atomized Ti powder was used for starting powder. As a result of using Mo vessel and sponge Ti, sintered Ti compact at 1523 K showed the excellent mechanical properties (tensile strength: 522 MPa, elongation: 21%), which was similar to JIS 3 grade of wrought Ti. This was due to the protection of oxidization. By blending with Hydride dehydrozation powder (high oxygen content) and gas atomized powder, tensile strength was improved significantly without large loss of the ductility (600 MPa, 13%). This seemed to be due to the high oxygen contents and more uniform oxygen distributions (solid solution strengthening). By MIM in-process nitriding combined with sintering appropriately, the surface hardness of Ti compacts increased dramatically and it decreased continuously to the inside.View full abstractDownload PDF (1700K) -
Tadashi Ogasawara, Kenichi Tada, Kazuomi Azuma, Takashi Onishi2002 Volume 49 Issue 9 Pages 829-833
Published: September 15, 2002
Released on J-STAGE: July 12, 2010
JOURNAL FREE ACCESSThe porous titanium sheet of 0.5 mm thickness was developed by the method of doctor blade using the spherical titanium powder with high quality. In this study, material properties of the Ti sheet were investigated by various evaluation methods. The properties investigated are porosity, mean pore diameter, tensile strength, deflective strength, bubble point pore diameter and air flow rate characteristic. This sheet made from spherical powder can keep its original particle shape and point contact each other by selecting the optimum sintering temperature. When the sintering temperature goes up, its porosity becomes lower than 45%. Tensile strength and deflective strength increase linearly with reducing the porosity, and can reach more than 100 MPa. Bubble point pore diameter ranges from 32 to 44μm. Differential pressure of this sheet by air flow is lower than that of the filter made from the irregular shape powder, and it can be further decreased by reducing the thickness of the sheet. The results mentioned above suggest that this porous titanium sheet has the excellent characteristics as the sintered metal filter.View full abstractDownload PDF (2971K) -
Yoshikazu Masai, Masashi Ishida, Shigeo Tanaka, Kazuaki Nishiyabu2002 Volume 49 Issue 9 Pages 834-840
Published: September 15, 2002
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe effect of copper-added content and sintering temperature on the mechanical properties and functionalperformances such as anti-bacteria and resist-corrosion for the stainless steel by metal injection molding wasinvestigated. The specimens were prepared by injection molding the mixed powders of water-atomized SUS304Land Cu with poly-acetyl binder. The green compacts were prepared at five steps of copper-added content fromOmass%Cu to s mass%Cu and they were sintered at the six steps of temperature from 1050 to 1350°C for 7.2ks in Argas after the debinding process at 600°C for 7.2 ks in NZ gas. The relative density and tensile strength of sinteredcompacts showed the minimum values by addition of 5mass%Cu and 8mass%Cu, respectively. They were modifiedup to original value by addition of IOmass%Cu and sintering at 1100°C. The anti-bacterial test based on film contactto bacilli and the quantitative analysis of copper ion dissolved to water showed high effective as increasing thecopper-added content. It was also confirmed from the measurement of pitting potential that copper addition modifiesthe resist-corrosion performance.View full abstractDownload PDF (5013K) -
Tatsuya Harikou, Yoshinori Itoh, Kenji Satoh, Hideshi Miura2002 Volume 49 Issue 9 Pages 841-845
Published: September 15, 2002
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSGenerally metal injection molding (MIM) process is utilized for mass production of near net shape forming complicated parts using single metal material. If plural metal materials are used in MIM process, multi-functional parts can be manufactured in high productivity and high quality.
In this study, the same stainless steels (SUS316L/SUS316L, SUS430L/SUS430L) and the different stainless steels (SUS316L/SUS430L) were joined by using insert injection molding. For joining the same stainless steels, the joining strength had reference to the joined area. In SUS316L joined compacts, joining strength showed a tendency to be in proportional to horizontal plane of joined area. For joining the different stainless steels, the compact was most rigidly joined at 1623 K. The new phases appeared at the joined area, which were mixture of ferrite and martensite because of the diffusion of Ni and Mo from SUS316L to SUS430L side.View full abstractDownload PDF (4289K)
- |<
- <
- 1
- >
- >|