All issues
Volume 58, Issue 11
November
Displaying 1-10 of 10 articles from this issue
- |<
- <
- 1
- >
- >|
Paper
Paper
-
Preparation of Submicron-size Permalloy Fine Particles by a Single Chemical Vapor Deposition ProcessKazutoshi Hanada, Shin Ishikawa, Kyoko Fujimoto, Kensuke Matsuki2011 Volume 58 Issue 11 Pages 645-648
Published: 2011
Released on J-STAGE: January 11, 2012
JOURNAL OPEN ACCESSFine particles of permalloy (80wt%Ni-20wt%Fe) were prepared by a CVD (chemical vapor deposition) method using the original quartz reactor. The mixture of FeCl2 and NiCl2 was vaporized and reduced to Ni-Fe fine particles in H2 flow. The average particle diameter was 0.17 micrometer. The particle composition was controlled by the change of the reaction temperature and reaction time. The initial permeability and density of 80wt%Ni-20wt%Fe particles synthesized at 950°C were almost the same to those of the bulk alloys.View full abstractDownload PDF (611K) -
Young Joon An, Podpichai Soonpan, Ken Nishida, Takashi Yamamoto, Shunk ...2011 Volume 58 Issue 11 Pages 649-654
Published: 2011
Released on J-STAGE: January 11, 2012
JOURNAL OPEN ACCESSIn general, there are two types as practical microwave absorbers; resonant or graded dielectric. Especially the resonant absorber is used as the simplest type of absorber which consists of a resistive sheet spaced one-quarter wavelength from a conductive ground plane. In this study, we propose the new type of resonant absorber which consists of magnetic (Fe) and dielectric (TiO2) composite material, metal pattern sheet, no loss dielectric material and metallic plate at the back. The composite microwave absorber with metal pattern sheet was applied in the design of a microwave absorber for high frequency region. The central frequency of absorption and the reflection loss could be controlled by changing the size and interval of metal pattern. By optimizing composition of absorbing layer and geometry of metal pattern, thinner and lighter composite microwave absorber with metal pattern satisfied the necessary conditions of central frequency 5.8 GHz and reflectivity -20 dB or more around for ETC use in Japan.View full abstractDownload PDF (1116K) -
Takanori Kadokura, Yutaka Hiraoka, Akihiko Ikegaya2011 Volume 58 Issue 11 Pages 655-660
Published: 2011
Released on J-STAGE: January 11, 2012
JOURNAL OPEN ACCESSEffects of sintering conditions such as heating temperature and heating rate on the density and microstructure of a sintered body of molybdenum were investigated. Both the oxygen content and the density of an intermediate sintered body influenced the density and the microstructure of the sintered body. First, the sintered body with a higher density and with a smaller number of pores was obtainable from the intermediate sintered body with lower oxygen content and with a lower density. Secondly, the grain size of the sintered body tended to decrease almost linearly with the increase of the number of pores. The latter result suggests that the grain growth in the sintered body was inhibited by the existence of pores at the grain boundaries.View full abstractDownload PDF (1600K)
Special Issue: New Development of Diverse Powder Forming Processes
Summarization
-
Hideshi Miura2011 Volume 58 Issue 11 Pages 662
Published: 2011
Released on J-STAGE: January 11, 2012
JOURNAL OPEN ACCESSDownload PDF (127K)
Review
-
Jai-Sung Lee, Woo-Kyung You, Joon-Phil Choi2011 Volume 58 Issue 11 Pages 663-672
Published: 2011
Released on J-STAGE: January 11, 2012
JOURNAL OPEN ACCESSThis paper reviews our recent investigations for finding a breakthrough for processing of net-shaped powder metallurgical parts using nanopowders. Especially, the issues on low-temperature powder injection molding of the Fe nanopowder- and micro-nano powder feedstock using a low melting binder are introduced. Relating to consolidation of the nanopowders by pressureless sintering, understanding nanopowder agglomerate sintering (NAS) process is essential to processing of net-shaped nanopowder materials and components. Based upon this concept, we have suggested a new idea of full density processing for fabricating micro-powder injection molded part using metal nanopowder agglomerates produced by hydrogen reduction of metal oxide powders. The debound (brown) part maintained uniform and sound surface structure due to strong networks between the micropowders by enhanced sintering effect of nanopowders during the debinding process. During sintering the PIM gear underwent isotropic shrinkage to reach full density while the micropowder grains rarely grew due to the inhibition effect of the nanopowders on the migration of micropowder grain boundaries. Conclusively, the use of micro-nano powder feedstock might provide a potential application for processing the PIM parts with full density and fine microstructure.View full abstractDownload PDF (2287K)
Paper
-
Yang Xu, Fujio Tsumori, Hyungoo Kang, Hideshi Miura2011 Volume 58 Issue 11 Pages 673-678
Published: 2011
Released on J-STAGE: January 11, 2012
JOURNAL OPEN ACCESSIn this report, an improved fabrication method of micro powder imprinting (μPI), which has the industrial value in reducing of the cost and procedures, is introduced to fabricate the thin yttria-stabilized zirconia (YSZ) sheet with the micrometer scale patterns. The Kapton film mold was designed and employed in thermal imprinting in order to prevent the breakage of sheet as mold removing. After imprinting, debinding and sintering procedures, the well pattern consistence line and space patterns in scale of 8 μm were obtained on 300 μm thick ceramic sheets. The morphology of sintered ceramic patterns was observed and the behaviors of debinding and sintering were investigated in this report. Meanwhile, the imprinting on bilayer ceramic sheet was carried out and the results showed the well wave interface of each layer, which have the potential utilization for solid oxide fuel cell directly.View full abstractDownload PDF (1821K) -
Hikaru Ikeda, Toshiko Osada, Hyung-Goo Kang, Fujio Tsumori, Hideshi Mi ...2011 Volume 58 Issue 11 Pages 679-685
Published: 2011
Released on J-STAGE: January 11, 2012
JOURNAL OPEN ACCESSSuperalloys have been used especially for aerospace and atomic energy applications because of their excellent attributes of high corrosion and oxidation resistance, and high temperature strength. A Inconel 718 is one of representative Ni-base superalloys. However, it is not easy to produce the complicate shaped parts with low cost due to their poor workability. In this study, Metal Injection Molding (MIM) process, one of near net-shape powder forming, has been applied to fabricate the Inconel 718 alloy compacts using two type of powders; gas and water atomized powders. By optimizing the MIM process, their obtained relative density was near full density (98∼99 %). However, the fatigue strength of heat treated sintered Inconel 718 compacts showed 65 % of heat treated wrought materials due to the remained pores. The effect of remained pores on fatigue strength was discussed by the prediction equation of endurance limit considering the inclusion.View full abstractDownload PDF (1453K) -
Tomoyuki Okuni, Weiwu Chen, Tetsuro Tojo, Miyamoto Yoshinari, Makio Na ...2011 Volume 58 Issue 11 Pages 686-691
Published: 2011
Released on J-STAGE: January 11, 2012
JOURNAL OPEN ACCESSGraphite material and AlN ceramic were joined successfully using an interlayer tape of Ceramic Bonded Carbon (CBC) by spark plasma sintering. The CBC tape was prepared from the slurry of graphite and AlN powders by tape casting method. The CBC interlayer sintered consists of graphite particles bonded with the three-dimensional network of AlN thin layer. The graphite and AlN joints were analyzed by SEM observation, XRD phase identification, and EDX elements distribution. There were no cracks and voids at interfaces of AlN ceramic layer, CBC interlayer and graphite materials. It was suggested that the joining was performed mainly by sintering of AlN through the AlN ceramics layer and the CBC interlayer, and physical bonding between the CBC layer and graphite. The thickness of AlN layer and the CBC interlayer was about 3 % and 4 %, respectively, against the entire thickness of graphite and AlN joint. Nevertheless, the joints showed much higher strength of 82 MPa than the graphite's strength of 41 MPa. Graphite-AlN joints would be expected to use as light, insulative and high heat-conductive substrates or components.View full abstractDownload PDF (1529K) -
Shigeru Unami, Takuya Goushi, Kentaro Kudo, Fujio Tsumori, Hyung-Goo K ...2011 Volume 58 Issue 11 Pages 692-696
Published: 2011
Released on J-STAGE: January 11, 2012
JOURNAL OPEN ACCESSSurface rolling were carried out using P/M spur gears of 0.6Mo-0.2C partially alloyed sintered steel with the density of 7.18 g/cm3. A CNC form rolling machine of axis intersection type was employed, and an unmodified screw-shaped rolling tool was prepared. Then, porosity distributions in the surface layer of rolled gear teeth root were measured and the effects of the surface rolling on the selective surface densification behaviors were evaluated. Moreover, to obtain higher fatigue strength, reverse rolling was introduced to standard gears. As a result, the porosities in the tooth root were sufficiently reduced at 700 μm feed in rolling process. Furthermore, a profile shifted gear was prepared to increase the effect of surface rolling. After case hardening, the single tooth bending fatigue durability reached to about 83 % of the case hardened wrought steel gears of SCM415.View full abstractDownload PDF (991K)
JSPM Announcements
-
2011 Volume 58 Issue 11 Pages Pref11_1
Published: 2011
Released on J-STAGE: January 11, 2012
JOURNAL OPEN ACCESSDownload PDF (119K)
- |<
- <
- 1
- >
- >|