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Volume 59, Issue 2
February
Displaying 1-13 of 13 articles from this issue
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Special Issue: Recent Study for Metallic Glasses and Nano Structural Materials
Summarization
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Akihisa Inoue2012 Volume 59 Issue 2 Pages 56
Published: February 15, 2012
Released on J-STAGE: April 24, 2012
JOURNAL OPEN ACCESSDownload PDF (110K)
Paper
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Osami Haruyama, Hiroyuki Sawada, Kazuhiro Yoshikawa, [in Japanese], Yo ...2012 Volume 59 Issue 2 Pages 57-62
Published: February 15, 2012
Released on J-STAGE: April 24, 2012
JOURNAL OPEN ACCESSThe inhomogeneous character of structural relaxation in Zr-based bulk metallic glass (BMG) was investigated from both aspects of the fine structure of free volume, i.e. like the identification of n-, p-type defects, and the chemical short-range order (CSRO) induced by thermal treatment. At least within volume relaxation used in the present study the fine structure of free volume could not be detected. On the other hand, the CSRO process was confirmed to take place in a Zr50Cu40Al10 BMG by electrical resistance experiments. Although the fine structure of free volume could not be observed in the present glass, the existence of the CSRO process suggests any structural inhomegeneity in BMGs.View full abstractDownload PDF (646K)
Review
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Katsuji Tosha2012 Volume 59 Issue 2 Pages 63-66
Published: February 15, 2012
Released on J-STAGE: April 24, 2012
JOURNAL OPEN ACCESSThis review describes on the types and characteristics of the main media for shot peening. Shot peening is a cold working process impacting the work material using spherical particles and producing the surface texture covered with uncountable dents and surface integrity beneath the peened surface. As the working device of shot peening is small shots, the surface roughness is homogeneous and narrow area can be peened such as the inside of coil springs, pipes and deddendum flank of gears. As the results, shot peening improves the mechanical properties such as fatigue, stress corrosion cracking, wear, and also improves effects on the flow resistance coefficient of the peened surface and on the heat transfer characteristics. The types of peening media treated in this paper are cast steel, cut wire, conditioned cut wire, glass, ceramics, stainless steel, cemented carbide, high speed steel and amorphous.View full abstractDownload PDF (698K) -
Masahiro Fukumoto2012 Volume 59 Issue 2 Pages 67-71
Published: February 15, 2012
Released on J-STAGE: April 24, 2012
JOURNAL OPEN ACCESSSome kinds of metallic powder particles were thermally sprayed onto the mirror polished metallic substrate surface and the effect of both substrate temperature and ambient pressure on the flattening behavior of the particle was systematically investigated. In the flattening behavior of the sprayed particle onto the substrate surface, critical conditions were recognized both in the substrate temperature increasing and ambient pressure decreasing. That is, the flattening behavior changed transitionally from splash shape to disk one on that critical temperature and pressure range, respectively. A transition temperature, Tt, and transition pressure, Pt, were defined and introduced, respectively for those critical conditions. Correspondingly, the coating adhesion property changed transitionally on that critical temperature and pressure range, respectively. Three dimensional transition curvature by combining both transition temperature and transition pressure dependence was proposed as a practical and effective controlling principle of the thermal spray process. The fact that the dependence of both transition temperature and transition pressure on the sprayed particle material had similar tendency indicated that the dynamic wetting of the substrate by the molten particles seemed to be a domination in the flattening.View full abstractDownload PDF (907K)
Special Issue: Functional Oxide Materials
Summarization
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Yuichi Shimakawa2012 Volume 59 Issue 2 Pages 74
Published: February 15, 2012
Released on J-STAGE: April 24, 2012
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Paper
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Masaya Amimoto, Takeshi Kimura, Masaaki Haneda, Masakuni Ozawa2012 Volume 59 Issue 2 Pages 75-79
Published: February 15, 2012
Released on J-STAGE: April 24, 2012
JOURNAL OPEN ACCESSWe investigated the optical properties for CeO2-ZrO2 system powders synthesized by coprecipitation method and heated at 900°C. For x=0.4 to 0.7 in ZrxCe1-xO2, XRD revealed two phases existed: Ce-rich CeO2-ZrO2 solid solution with cubic fluorite structure and Zr-rich CeO2-ZrO2 solid solution with tetragonal pseudo-fluorite structure. For x=0.2 to 0.8, b∗ values showed about 40, and vivid yellow powders were obtained. Diffuse reflectance spectra of the powder in the UV region showed the broad shoulder-type band at 320-350 nm, which is assigned to interband transitions in CeO2. The Zr-doping in CeO2 extended the light absorption range by the interband transitions into visible light region. The light with wavelengths corresponding to purple and blue were absorbed, so that the powders showed yellow corresponding to the complementary color.View full abstractDownload PDF (508K) -
Masakuni Ozaw, Osamu Kato, Naokage Tanaka, Wei Yang, Masaaki Haneda2012 Volume 59 Issue 2 Pages 80-84
Published: February 15, 2012
Released on J-STAGE: April 24, 2012
JOURNAL OPEN ACCESSWe investigated the effect of La addition on thermal stability and benzene removal activity of iron oxide/alumina composite powder catalyst. La addition to alumina support improved the surface area stability and the total catalytic removal conversion of benzene after heat treatment. The solid state reaction in La-added catalyst was complicated: γ-Al2O3, LaFeAl11O19, LaAlO3 and α-Al2O3 appeared in this system. It was found that Fe/La/Al2O3 with high surface area was better catalyst for benzene removal at moderate temperature even when heated at 1000-1100°C. Also we discussed that La modification increased surface active sites as well as oxygen storage capacity.View full abstractDownload PDF (680K) -
Masahiro Sakai, Kouki Nakajima, Osami Seri2012 Volume 59 Issue 2 Pages 85-89
Published: February 15, 2012
Released on J-STAGE: April 24, 2012
JOURNAL OPEN ACCESSA new method for the synthesis of powder using a corrosion reaction of metal in alcohol is proposed. Manganese has been dissolved in anhydrous methanol solvent containing ferric chloride as a catalyst by refluxing at 348 K for a period of 7.2 ks. A greenish-black precipitate has been obtained by adding the hydrated solution into NaOH solution at pH 12. This precipitated powder was identified as a manganese ferrite of MnFe2O4 by XRD analysis and showed characteristics of a soft ferrite by measuring a magnetic hysteresis loop. SEM observation and measurement of particle size distribution revealed that the powders were coagulation of submicron meter size particles. The preparation of MnFe2O4 was explained as mixed corrosion products of manganese with ferric hydroxide derived from addition of FeCl3.View full abstractDownload PDF (654K) -
Masanori Okada, Takashi Teranishi, Hidetaka Hayashi, Akira Kishimoto2012 Volume 59 Issue 2 Pages 90-94
Published: February 15, 2012
Released on J-STAGE: April 24, 2012
JOURNAL OPEN ACCESSWe have already proposed and demonstrated novel ceramic foams named "superplastically foamed ceramics" utilizing the superplastic deformation. Since almost all the processes are carried out in solid phase, figure and the location of the foaming agent can be controllable, leading to desired patterning of closed pore in a fully densified ceramics. We have already demonstrated two-dimensional (2D) pore patterning through the superplastically foaming method. In the present study, we aim to fabricate helical tubular pore in zirconia based ceramics as a typical 3D patterned pore. As a foaming agent, SiC powders were used with a form of thin sheet based on methylcellulose aqueous solution followed by drying. A core cylindrical matrix compact was first fabricated using φ 10 steel die and the liner foaming agent was attached to make helical pattern. The patterned core matrix was placed in φ 14 or φ 15 steel die and pressed together with the filled matrix powder. The resultant powder compact was heat treated at 1600°C for 8h for sintering followed by foaming to give a ceramics with 3D tubular pore. Continuous upheaval reflecting the tubular pore was clearly observed on the side wall of the cylinder and helical tubular pore with different pitch can be fabricated.View full abstractDownload PDF (884K) -
Yui Watanabe, Masahiro Kubota2012 Volume 59 Issue 2 Pages 95-100
Published: February 15, 2012
Released on J-STAGE: April 24, 2012
JOURNAL OPEN ACCESSIn order to fabricate the aluminium based composite materials exhibiting phosphorescence properties, aluminium powder and phosphorescence powder (LG) were mechanically alloyed (MAed) using a vibrational ball mill, and the MAed composite powders were consolidated into bulk materials by spark plasma sintering (SPS). Changes in hardness, constituent phases, powder particle sizes and luminance of both the MAed powders and SPS materials were examined by a hardness tester, X-ray diffraction, scanning electron microscopy and luminance meter, respectively. The Vickers microhardness of the MAed powders increased both an increase in MA time and the amount of LG powder addition. No solid-state reactions could be detected in the MAed powders. The mean particle size of the MAed powders for 60 min was smaller than that for 5 min. The Vickers hardness of the bulk SPS materials increased both an increase in MA time and the amount of LG powder addition. SPS materials showed luminance properties in a darkroom after they were irradiated under black light. The optimum process conditions for MA time was 5 min and for the sintering temperature was 873 K.View full abstractDownload PDF (1124K) -
Yasushi Idemoto, Misato Tashiro, Naoto Kitamura2012 Volume 59 Issue 2 Pages 101-109
Published: February 15, 2012
Released on J-STAGE: April 24, 2012
JOURNAL OPEN ACCESSIn recent years, a development of lead-free piezoelectric ceramics is highly expected from the viewpoint of an environmental load, and BaTiO3 can be regarded as one of the candidates. In this study, we synthesized BaTiO3 powders by solid-state and hydrothermal methods, then sintered them by a two-step sintering process in addition to a conventional one. By performing Rietveld analyses using the neutron diffraction data, we examined effects of the preparation process on the crystal structures, and then discussed a relationship between the piezoelectric properties and the crystal structure. From SEM observations, it was found that the two-step sintering made densities of the ceramics slightly higher and suppressed the grain growth compared with the normal sintering, regardless of the powder synthesis process. It was also demonstrated that the two-step sintering enhanced piezoelectric properties in the case of the samples prepared by the solid-state method. One the other hand, a sample synthesized by the hydrothermal process with the two-step sintering exhibited lower Tc, εs and d33 due to the size effect. From crystal structure analyses, it was revealed that a change in a tetragonality of the crystals by the sintering process depended considerably on the powder synthesis process.View full abstractDownload PDF (1856K) -
Naoyuki Tsukamoto, Yuki Sakamoto2012 Volume 59 Issue 2 Pages 110-115
Published: February 15, 2012
Released on J-STAGE: April 24, 2012
JOURNAL OPEN ACCESSThe Bi2O3 based ZnO varistors (MOVs) are used in surge arresters or surge protective devices (SPDs) as key components. As their performance, MOVs shall have I-V non ohmic characteristics, higher surge withstand capability and reliability for ageing: When AC power line voltage is applied to MOV, its leakage current or watt loss shall be decreased continuously.
In order to maintain reliability for ageing, it is known that additional heat treatment after sintering process in MOV manufacturing flow is effective. The mechanism of the heat treatment effect was considered to be realized by a crystal structure change of the bismuth oxide as a main material which forms a grain boundary. However, in this study, it is found that watt loss behavior does not necessarily correspond to crystal structure of the bismuth oxide. Besides, from the fact that ZnO which dissolve in Bi2O3 liquid phase is compounded with other additives by heat treatment, precipitation of ZnO in Bi2O3 liquid phase by heat treatment can be considered as important factor.
In addition, uniformity not only in grain boundary structure from a microscopic of view, but also of size and its distribution of the multiple points from a macroscopic of view is integrant in order to realize MOVs having lower watt loss and its stability.View full abstractDownload PDF (1651K)
JSPM Announcements
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2012 Volume 59 Issue 2 Pages Pref2_1
Published: February 15, 2012
Released on J-STAGE: April 24, 2012
JOURNAL OPEN ACCESSDownload PDF (57K)
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