All issues
Volume 50, Issue 10
Displaying 1-12 of 12 articles from this issue
- |<
- <
- 1
- >
- >|
-
Malleable Platinum by William H. William H. Wollaston and Its Historical BackdropTadashi Igarashi2003 Volume 50 Issue 10 Pages 731-736
Published: October 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSWilliam Hyde Wollaston, an English scientist, have developed outstanding powder metallurgical process for malleable platinum in 1804. This have been considered as the beginning of modern powder metallurgy based on science. The process included some key techniques: purification and micronizing powder in refining of crude metal, compressing of powder under high pressure and sintering at high temperature, which are still important even now. Technical advantage of purification and compressing of powder were accomplished besed on chemistry and mechanics, respectively. Malleable platinum over 1.1ton for various uses was produced by Wollaston for fifteen years.
In this paper, the great accomplishment of Wollaston and its historical backdrop are looked back through two Wollaston's papers on malleable platinum, some articles on the relics handed down by Wollaston and history books on platinum.View full abstractDownload PDF (5656K) -
Akiko Kitajima, Toru Shimizu, Atsuo Ito2003 Volume 50 Issue 10 Pages 739-744
Published: October 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThough Ti and Ti alloy with thermal sprayed apatite coatings have been applied to artificial joints and dental implants, the coatings are hard to combine directly with the substrates. In this study, a new rapid and easy surface treatment, by which the reactants can combine to the substrates directly, has been invented. It is a high apatite forming method. Among the substances generated by the treatment, one shows strong alkali, and others are considered to act as kernels during the bone-like apatite layer growth process. From these kernels, effective bone-like apatite layer can form on the surface of the substrates in a simulated body fluid (SBF).View full abstractDownload PDF (5099K) -
Hiroaki Katsuki, Sridhar Komarneni2003 Volume 50 Issue 10 Pages 745-750
Published: October 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSMicrowave-solvothermal processes have been previously found to be highly suited for the synthesis of a wide variety of ceramic and metal powders. In this paper, the effect of microwave radiation on the formation of Ag powders from AgNO3 using ethylene glycol as a reducing agent at 100-200°C was investigated. Silver powders were rapidly produced by using microwave radiation. The formation yield of Ag powders from AgNO3 reached 98.6% by treatment for 23 min at 160°C and 97.4% by treatment for 2 min at 200°C using the microwave-polyol (M-P) process. Silver powders of 0.15 to 1.0, 0.15 to 1.2, and 0.35 to 1.8μm in diameter were produced at 100°C in 10, 20, and 30 min, respectively via M-P reaction. The particle size increased further and then strongly aggregated at 160 and 200°C. By the addition of polyvinyl pyrrolidone (PVP) as a protective polymer to the mixture of AgNO3 and ethylene glycol which was treated at 160°C, smaller Ag particles of 62 to 78 nm in diameter were obtained.View full abstractDownload PDF (2953K) -
Yoshinori Fujikawa, Fumikazu Yamane, Takeshi Nomura2003 Volume 50 Issue 10 Pages 751-756
Published: October 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe microstructural change in the solid-state reaction of BaCO3 and TiO2 to form BaTiO3 has been investigated by using Scanning Transmission Electron Microscopy (STEM). The STEM images showed that the film of BaTiO3 formed at the surface of TiO2 particle in the first stage of this reaction. As the reaction progressed, the film thickened toward the center of TiO2 particle without forming intermediate phase such as Ba2TiO4. The influence of anion addition on the reaction rate in this solid-state reaction was also investigated. The addition of BaCl2 accelerated the formation of BaTiO3.View full abstractDownload PDF (5742K) -
Tsuyoshi Morishita, Hidenori Kuroki, Miyuki Kumagai2003 Volume 50 Issue 10 Pages 757-763
Published: October 15, 2003
Released on J-STAGE: July 12, 2010
JOURNAL OPEN ACCESSThe effect of phosphorous and carbon contents and sintering conditions on the wear resistant properties of ferrous sintered materials were investigated. Wear test was conducted using the sintered material as the pin and hard Cr-plated Al-alloy disk as the mating material. By choosing compacting pressure of 490MPa and sintering conditions of 1203 K and 0.3 ks for Fe-5.6mass%P-1.6mass%C alloyed powder, the porosity of 5.5%, the average pore size of 23μm and the average grain size of 15μm were obtained. Proper anti-wear characteristics are obtained after making the fine-grained microstructure. Minimum wear amount was achieved on the Fe-5.5 mass%P-2.0mass%aC-3.0mass%Ni-3.0mass%Mo alloyed powder specimen pressed at 294 MPa, sintered in vacuum at 1203 K for 0.3 ks and heat-treated. The specimen shows 0.7% porosity, the average pore size of 8μm, the average grain size of 15μm, and the macro-hardness of Hv700 with a hardened matrix.View full abstractDownload PDF (2329K) -
Koki Kanno, Yoshinobu Takeda, Lindqvist Björn, Yosihisa Ueda2003 Volume 50 Issue 10 Pages 764-773
Published: October 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSPartially diffusion bonded alloy has been used for components which require high mechanical properties. Secondary operations as a Carburizing are used for these materials to achieve higher strength. Prealloyed 3Cr-0.5Mo powder can have excellent mechanical properties when it is sintered at 1250 °C. Though this material has introduced in the market in 1998, it has not been evaluated completely about Fatigue Strength after Carburizing and Shot Peening Process that are common process to achieve higher fatigue strength in wrought steels. Considerations when applying such secondary operations to these materials in different conditions are given in this paper.View full abstractDownload PDF (687K) -
Takeshi Matsumoto, Shoji Miyake2003 Volume 50 Issue 10 Pages 774-779
Published: October 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSSrBi2Ta2O9 (SBT) films were spin-coated on Pt/Ti/SiO2/Si, and subsequently annealed by millimeter-wave heating as well as electric furnace one. It was found that remnant polarization of films annealed by millimeter-wave was higher than those by electric furnace heating, and it was attributed to better crystallinity and suppression of formation of non-ferroelectric pyrochlore phase in the millimeter-wave annealing. Enhancement of diffusion by millimeter-wave irradiation is suggested to bring about improvement of crystallinity. Additionally, the Pt layer is considered to be kept at lower temperature due to lower millimeter-wave absorption of Pt, and inter-diffusion among SBT, Pt and Ti layers, which causes formation of non-ferroelectric pyrochlore phase, is inhibited.View full abstractDownload PDF (2067K) -
Atsushi Iwata, Kazuyuki Yamaguchi, Toshikazu Shimoyama, Nobuyasu Kawai2003 Volume 50 Issue 10 Pages 780-784
Published: October 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSFatigue crack propagation behavior was investigated for high tensile sintered steels of about 1000MPa level.
It was made clear that the diffusion bonded steel was most excellent as for the fatigue crack propagation behavior. The difference of fatigue crack propagation behavior with the different Ni content and sintered density was found to be significant, even if the alloying method was the same.
As for high tensile sintered steel, it was found that fatigue crack propagated through grain boundaries.View full abstractDownload PDF (2942K) -
[in Japanese]2003 Volume 50 Issue 10 Pages 786
Published: October 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSDownload PDF (88K) -
Yuko Sawaki, Kazutaka Matsuo, Mikio Kishimoto2003 Volume 50 Issue 10 Pages 787-791
Published: October 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSWe synthesized nano sized cerium and zirconium oxide particles by the hydrothermal treatment of precipitates formed from the chlorides of each metal ion. Especially the cerium oxide particles had plate-like shapes with the particle size in the range of 2-20 run. Even in the particle size of 2nm, most of the cerium oxide particles observed by a high resolution transmission electron microscope showed clear lattice images based on (111) and (200) planes indicating the plate-like single crystals. In the zirconium oxide particles, it was confirmed that the single phases of monoclinic and tetragonal crystals were obtained by the hydrothermal treatment lower than 200°C maintaining the particle size of about 10nm.View full abstractDownload PDF (5161K) -
Hideo Okuyama, Masahiro Uda, Tetuo Uchikoshi, Touru Suzuki, Yoshio Sak ...2003 Volume 50 Issue 10 Pages 792-797
Published: October 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSIn order to find a new energy-saving-powder manufacturing process, the pulverization due to hydrogenation of Nb-Zr-Fe alloys with 35 different compositions has been studied. The hydrogenation was performed under the hydrogen atmosphere of 0.1 MPa and room temperature in an arc melting chamber without exposure to air after arcmelting.
Nb-Zr-Fe alloys absorb a large amount of hydrogen from 0.1 to 1.8 wt%H and pulverize into powders. This pulverization is closely related to the composition of alloys.
The composition which is easy to pulverize is concentrated to the ranges of 15 at%Fe in Nb-Zr-Fe alloys and 15-30 at%Fe with fixed to Nb/Zr??1/1 in Nb-Zr-Fe alloys. For an example, hydrogen absorbed powder of 45Nb-40Zr-15Fe alloy has wide size distribution from 5 to 200 micron with flake figure and with many fine cracks.
The hydrogen in powder of 45Nb-40Zr-15Fe alloy is stably stable until 473 K and dehydrogenation temperature is from 473 K to 773 K.
It is estimated that hydrogenation is induced by proper amount of iron element in Nb-Zr-Fe alloys and a hydrogen rich phase and a hydrogen poor phase are formed in an alloy ingot. Forming of two phases by absorbing hydrogen causes to pulverization of Nb-Zr-Fe alloys.View full abstractDownload PDF (3805K) -
Satoshi Uenosono, Yukiko Ozaki2003 Volume 50 Issue 10 Pages 798-805
Published: October 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSStearamide, ethylene-bis-stearamide, polyethylene, PMMA and zinc stearate were used as lubricant in the segregation-free iron mixed powders. The difference in lubricant's substance affected strongly on the frictional properties and character such as the flow rate and index of discharging from hopper of the segregation-free iron mixed powders. The adhesive forces (FH) were calculated with the result of the shear test of the sample powders. The value of FH/d2, in which d was the average diameter of the powder, is a good index for the flow character. The flow character of the powder improved with a decrease in the value of FH/d2.View full abstractDownload PDF (592K)
- |<
- <
- 1
- >
- >|