Journal of the Japan Society of Powder and Powder Metallurgy
Online ISSN : 1880-9014
Print ISSN : 0532-8799
ISSN-L : 0532-8799
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Volume 54, Issue 12
December
Displaying 1-13 of 13 articles from this issue
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Paper
Paper
  • Study on Coating Method of Ag/Al2O3 Catalyst System on the Stainless Steel
    Satoshi Kishida, Dong-Ying Ju
    Article type: Paper
    2007 Volume 54 Issue 12 Pages 805-808
    Published: 2007
    Released on J-STAGE: July 29, 2008
    DOIhttps://doi.org/10.2497/jjspm.54.805
    JOURNAL OPEN ACCESS
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    A coating process of Ag/Al2O3 catalyst powder on an aluminum-free stainless steel has been investigated for NOx reduction. The stainless steel SUS304 was coated with γ-Al2O3 powder or Ag/Al2O3 catalyst powder by dip coating method using aluminum nitrate as a binder and heated in air. The heating temperature was determined by TG-DTA analysis and the heating period, the concentrations of the binder and the coating powder as well as the number of coats were changed to optimize preparation conditions. As a result, a coating layer with a thickness of approximately 4-5μm was formed on SUS304 without exfoliation. A catalytic ability of the coated sample for NOx reduction was highly enhanced as compared with that coating the catalyst powder without the binder on γ-Al2O3 coating layer.
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  • Preparation of Ti-Al-Si Spattering Target by Pulse Current Pressure Sintering
    Takekazu Nagae, Masateru Nose, Masaru Yokota, Hirofumi Suzuki, Yoshio ...
    Article type: Paper
    2007 Volume 54 Issue 12 Pages 809-815
    Published: 2007
    Released on J-STAGE: July 29, 2008
    DOIhttps://doi.org/10.2497/jjspm.54.809
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    We investigated the relationships between sintering conditions of TiAlSi mixed powder and microstructures of the sintered compacts for the purpose of fabricating large sputtering targets (such as 160 mm ×100 mm). The pulse current pressure sintering (PCPS) method was employed in order to consolidate the mixed powders consisting of Ti50:Al40:Si10 (atomic %). Ti50Al40Si10 compacts were made under conditions of various pressures (49∼98 MPa) and temperatures (773 K∼873 K). When the sintering temperature was 833 K or higher, Al-Si liquid oozed out during the process. When the sintering temperature was lower than 833 K, many micro pores have been formed in the sintered compact. When the sintering pressure was high, the relative density of the compact was higher and metallic compounds have formed at the interface between Ti and Al/Si. Relative density of 97% was obtained from the compact sintered at 823 K under the pressure of 60 MPa. Water quenching test revealed that this sintered compact had high resistance to thermal shock due to the formation of metallic compounds. Applying this sintering condition, disk compacts of Φ190 mm×8 mm were successfully obtained and 160 mm×100 mm rectangular sputtering targets were fabricated from these disks.
    Then we investigated the microstructure and mechanical properties of Ti-Al-Si-N films deposited from the rectangular targets to confirm whether the targets are useful for sputtering. The targets were sputtered in a mixture of argon and nitrogen using an r.f. sputtering apparatus of facing target-type sputtering. The Ti-Al-Si-N films obtained the highest hardness of 43 GPa when they were deposited at 573 K without substrate bias. The hardness of the films was ∼20% higher than that of Ti-Al-N films. These results indicate that the Ti50Al40Si10 compacts sintered by PCPS are useful for sputtering targets.
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Special Issue:Nature-guided Materials Processing
Summarization
Review
Paper
  • Aqueous Solution Synthesis of Anatase TiO2 Particles
    Yoshitake Masuda, Kazumi Kato
    2007 Volume 54 Issue 12 Pages 824-827
    Published: 2007
    Released on J-STAGE: July 29, 2008
    DOIhttps://doi.org/10.2497/jjspm.54.824
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    TiO2 particles were prepared in aqueous solutions at 50°C. They were in a single phase of anatase TiO2 and about 800 nm in diameter. They were constructed of nano TiO2 crystals to have nano-sized relief structure on surfaces. TiO2 particles exhibited N2 adsorption-desorption isotherms of type I. BET specific surface area of the particles was estimated to 168 m2/g. The particles were prepared without high temperature annealing which caused aggregation and crystal growth of particles. It was confirmed that the solution process has a high ability to prepare anatase TiO2 particles having high BET surface area.
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Review
  • Fabrication Process of Biomaterials through Biomineralization-Guided Concept
    Chikara Ohtsuki, Akari Takeuchi
    Article type: Review
    2007 Volume 54 Issue 12 Pages 828-833
    Published: 2007
    Released on J-STAGE: July 29, 2008
    DOIhttps://doi.org/10.2497/jjspm.54.828
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    Bioactive ceramics are now clinically used as artificial bones because they can make direct bonding to bone after implantation in bony defects. However, there are some limitations in their application due to the more brittleness and lower fractured toughness of the ceramics than those of bone. Since bone consists of hydroxyapatite and collagen, composites consisting of bone-like apatite and organic polymer is an important candidate for production of novel artificial bones. This paper reviews some of approaches to fabricate such a composite through the biomineralization-guided concept utilizing a simulated body fluid (SBF) that mimics human extracellular fluid. To deposite bone-like apatite on the organic polymer in SBF, functional groups on the polymer surface is an important parameter to induce heterogeneous nucleation of hydroxyapatite as well as increase in the degree of supersaturation with respect to hydroxyapatite through release of such ions as Ca2+. Arrangement of the functional groups on the substrates is also effective on nucleation of hydroxyapatite in addition to the kinds of the functional groups implying carboxyl groups. These molecular design brings novel biomaterials for bone substitutes with much compatibility to living bone.
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Paper
  • Control of Crystal Growth of ZnO Nanowhiskers in Aqueous Solution and Synthesis of Transparent Nanoarrays
    Xiulan Hu, Yoshitake Masuda, Tatsuki Ohji, Kazumi Kato
    Article type: Paper
    2007 Volume 54 Issue 12 Pages 834-838
    Published: 2007
    Released on J-STAGE: July 29, 2008
    DOIhttps://doi.org/10.2497/jjspm.54.834
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    Transparent and porous ZnO nanowhisker arrays were prepared in 0.025 M zinc nitrate-hexamethylenetetramine aqueous solutions with the addition of polyethylenimine (PEI) at a low temperature. The effect of free zinc ion concentration was controlled by changing the immersing temperatures at which the pre-treated FTO substrates were got into the mixing solution such as 25°C, 75°C and 85°C. The free Zn ion concentration is a main factor for control of the transmittance. It was found that high Zn ion concentrations resulted in relative thick white and low transparent ZnO film, while the low concentrations gave high transparenency in the nanoarray. A transmittance of about 85% for porous ZnO films with thickness of 800 nm in the visible range was achieved.
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  • Preparation of Nano α-Alumina Powder by Use of High Energy Ball Milling Process
    Hiroyuki Muto, Atsushi Miyazaki, Yusuke Daiko, Atsunori Matsuda, Motot ...
    Article type: Paper
    2007 Volume 54 Issue 12 Pages 839-842
    Published: 2007
    Released on J-STAGE: July 29, 2008
    DOIhttps://doi.org/10.2497/jjspm.54.839
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    Nanosized α-alumina powders were prepared by use of the high energy ball milling process from fine grain γ-alumina powders without heat treatment. The γ-alumina transformed to α-alumina powder with a size of about 26 nm by the milling process at 720 rpm for 10 h. It was concluded that the mechanical stress induced by the milling process was effective to produce the nanosized alumina powder.
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  • Preparation and Biological Properties of Saccharide-Modified Gold Nanoparticles
    Masayuki Toyoshima, Ken Ooya, Yoshiko Miura, Kazukiyo Kobayashi
    Article type: Paper
    2007 Volume 54 Issue 12 Pages 843-848
    Published: 2007
    Released on J-STAGE: July 29, 2008
    DOIhttps://doi.org/10.2497/jjspm.54.843
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    The gold nanoparticels were modified by biological active saccharides, and the properties of gold nanoparticle including protein recognition abilities were investigated.
    First, the gold nanoparticle with a diameter of about 8 nm was modified by lactose-substituted mercapto oligoethylene. The gold nanoparticle was water soluble, and aggregated by addition of the specific recognition lectin.
    Then, the gold nanoparticle with a diameter of 40 nm was prepared by glycopolymer cattying α-mannoside. The gold nanoparticle with mannose was readily water soluble, and showed pink colour. The UV-adsorption of the gold nanoparticle was increased by addition of the specific recognition lectin of Concanavalin A though other protein didn't change the UV spectra.
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  • Low-Temperature Fabrication of Semi-Circular Shaped ZnO Nanowhiskers Using an Aqueous Solution
    Xiulan Hu, Yoshitake Masuda, Tatsuki Ohji, Kazumi Kato
    Article type: Paper
    2007 Volume 54 Issue 12 Pages 849-853
    Published: 2007
    Released on J-STAGE: July 29, 2008
    DOIhttps://doi.org/10.2497/jjspm.54.849
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    Site-selective deposited ZnO nanowhiskers with semi-circular shape were fabricated on the substrates by a simple two-step approach using an aqueous solution at low-temperature of 100°C. The zinc hydroxide nitrate hydrate prepared by the ultraviolet irradiation was used as a template layer. The forced hydrolysis of a pre-existing template layer in situ at an initial stage in a 200-ml aqueous solution of zinc nitrate hexahydrate-hexamethylenetetramine-polyethylenimine promoted heterogeneous nucleation and growth of ZnO nanowhiskers by site-selective deposition and resulted in the formation of semi-circular shape.
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Review
  • Liquid Phase Patterning of Ceramic Films
    Yoshitake Masuda
    Article type: Review
    2007 Volume 54 Issue 12 Pages 854-862
    Published: 2007
    Released on J-STAGE: July 29, 2008
    DOIhttps://doi.org/10.2497/jjspm.54.854
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    Liquid Phase Patterning (LPP) of ceramic thin films were realized in the solutions using self-assembled monolayers (SAMs). The processes were developed based on scientific knowledge obtained from investigations of interactions and chemical reactions between functional groups of SAMs and ions, clusters and homogeneously nucleated particles in solutions. Several conceptual processes for LPP using SAMs as templates were proposed, and nano/micropatterns of ceramic thin films such as TiO2, Fe3O4, ZnO, etc. were successfully fabricated. The studies showed the good performance of environment-friendly chemistry for the fabrication of nano/micro ceramic devices.
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Memorial Lecture of JSPM Award
  • Development of Highly-Functional Ceramic Materials by Chemical Vapor Deposition
    Takashi Goto
    Article type: Memorial Lecture of JSPM Award
    2007 Volume 54 Issue 12 Pages 863-872
    Published: 2007
    Released on J-STAGE: July 29, 2008
    DOIhttps://doi.org/10.2497/jjspm.54.863
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    Chemical vapor deposition (CVD) has been commonly employed as a thin film processing, whereas thick films and bulk ceramic materials can be also obtained by modifying and optimizing CVD conditions and apparatus. The development of highly-functional bulk ceramic materials and thick films by CVD has been reviewed in this paper. Monolithic Ti3SiC2 bulk material was synthesized by CVD, and was identified as a machinable soft ceramic material. SiC and Si3N4 are hardly sinterable materials, thus sintering aids are inevitable to consolidate these powders. However, such aids would yield significant deterioration of their high-temperature performance. Thermal CVD can provide bulk bodies by enhancing deposition rates. CVD SiC bulk body was used to investigate intrinsic nature of SiC, particularly high-temperature oxidation mechanism. By introducing laser in CVD, the deposition rate was tremendously increased several 100 to 1000 times greater than that of conventional CVD. Laser CVD enabled one to realize thermal barrier coating of yttria stabilized zirconia (YSZ). This YSZ coating contained a large amount of nanopores being beneficial for thermal insulation. Plasma enhanced CVD produced characteristic Ru-C film, where Ru nano-particles dispersed in an amorphous C matrix. This film can be a promising catalytic electrode for oxygen sensors and fuel cells.
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Errata (Vol.54, No.10)
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