All issues
Volume 53, Issue 8
August
Displaying 1-10 of 10 articles from this issue
- |<
- <
- 1
- >
- >|
Paper
Rapid Communication
-
— Effect of Si Content for Thermal Resistance, Friction and Wear —Masami Ikeyama, Junho Choi, Setsuo Nakao, Soji Miyagawa2006 Volume 53 Issue 8 Pages 635-640
Published: 2006
Released on J-STAGE: January 30, 2007
JOURNAL OPEN ACCESSIn order to find Si-DLC films with more thermal stability, we have evaluated five types Si-DLC films (0, 4, 11, 21 and 29 at% Si) with changing the mixture ratios of two precursor gases (tetramethylsilane and toluene). We examined the effect of Si content and heat treatment at 770 K for 1.8 ks in the Air on mechanical properties, such as hardness, internal stress, friction coefficient and wear resistance. With the increase of Si content, internal stress of the film decreased, and the films which have more than 21 at% Si content did not decrease the hardness by the thermal treatment. The films of 11-21 at% Si content showed the lowest friction coefficient and the 21 at% Si content film showed the highest wear resistance after the annealing. Silicon oxide was formed on the surface of DLC film after the annealing. In the higher Si content film, the oxide layer seems to act as diffusion barrier of oxygen and they might prevent the graphitization of the Si-DLC films. The 21 at% Si content film is the most thermally stable in the five.View full abstractDownload PDF (1070K) -
— Effect of Positive Pulse Heights for Thermal Resistance, Friction and Wear —Masami Ikeyam, Junho Choi, Setsuo Nakao, Soji Miyagawa2006 Volume 53 Issue 8 Pages 641-646
Published: 2006
Released on J-STAGE: January 30, 2007
JOURNAL OPEN ACCESSWe found that the optimal Si content of thermally stable Si-DLC film made by plasma based ion implantation technique with positive-negative high voltage pulses was about 21 at%. The technique can heat up specimens by electron bombardment with controlling the positive pulse voltage. In order to find the optimal positive pulse voltage in the process, we have examined the effects of the pulse voltage on several mechanical properties, such as internal stress, hardness, friction coefficient and wear resistance with controlling the positive pulse voltage as 2, 4 and 6.3 kV. The temperature increased, and internal stress and hardness decreased, with increasing the pulse voltage. The Si-DLC film with 4 kV pulses (about 570 K) is the largest thickness, the lowest friction coefficient and the highest wear resistance. The film has kept very low friction coefficient even after the annealing of 870 K, 3.6 ks in the Air.View full abstractDownload PDF (819K)
Paper
-
Akinori Katsui, Hajime Chisaka, Hiroaki Matsushita2006 Volume 53 Issue 8 Pages 647-650
Published: 2006
Released on J-STAGE: January 30, 2007
JOURNAL OPEN ACCESSThe LixCoO2 gels are prepared using a sol-gel route from cobalt(III)acetylacetonate Co(OAc)2 and LiOH, and their structural changes with temperature are investigated using thermal gravimetric analyses, X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy. The results indicate that LixCoO2 is obtained by heating the gels at temperatures as low as 673 K in air, by adding an aqueous NH4OH to enhance a decomposition of Acetylacenate. Furthermore, LixCoO2 obtained by heating the gels at 1123 K shows a multilayer of thin crystals with a well-developed 003 diffraction.View full abstractDownload PDF (598K) -
Mitsuru Nakamura, Takashi Inagaki, Sang-Hak Lee2006 Volume 53 Issue 8 Pages 651-655
Published: 2006
Released on J-STAGE: January 30, 2007
JOURNAL OPEN ACCESSAustenite type stainless steel powders (SUS304L) with rapid solid sintering were investigated by condition of heating rate 10K/s constant. The sintering was at a constant temperature of 1573K and holding time changes from 60s to 360s. The cooling methods were done by 2 different types: cool in N2 gas and furnace cool. Sintered specimens were evaluated on each mechanical property. As a result, radial crashing strength was obtained almost the same values when holding time is over 300s compared with continuous furnace sintering condition. And, influence of cooling method (cool in N2 gas or furnace cool) was not observed. Dimensional change ratio gained good values compared by liquid sintering. The values were maxima as 1.5% contraction ratios for both outside and inside direction. In this experiment, rapid solid sintering was able to be finished only for 490s.View full abstractDownload PDF (1350K) -
Yutsuki Nishimura, Masaki Yasuoka, Takaaki Nagaoka, Yoshiaki Kinemuchi ...2006 Volume 53 Issue 8 Pages 656-660
Published: 2006
Released on J-STAGE: January 30, 2007
JOURNAL OPEN ACCESSEffects of liquid phase on microwave sintering with a frequency of 2.45 GHz of BaTiO3 ceramics were investigated. The additives to form the liquid were BaCO3, H3BO3 and BaB2O4. Addition of the liquid phase in microwave sintering promotes densification of BaTiO3 ceramics significantly, and densified ceramics were obtained by lower applied power and shorter processing time. Furthermore, electric resistivity of dense ceramics with BaCO3+2H3BO3 addition was different by sintering techniques, and a sample obtained by microwave sintering showed the dielectric, while one obtained by conventional sintering showed the semiconducting properties. Such different result is considered to be relating to presence of liquid phase with strong microwave absorption.View full abstractDownload PDF (574K) -
Koki Kanno, Satoshi Sunada, Kazuhiko Majima, Miho Ishida, Yoshinobu Ta ...2006 Volume 53 Issue 8 Pages 661-666
Published: 2006
Released on J-STAGE: January 30, 2007
JOURNAL OPEN ACCESSGeneral structural components are widely made of Fe-Cu-C sintered steels. However, corrosion behavior of these components was not clear, as there are lots of factors to determine corrosion speed. Therefore the influence of (1) purity for sintered steel of pure iron powders and (2) additives of different copper for sintered steels of Fe-Cu-C powders on their corrosion behavior was investigated by using electrochemical methods including electrochemcal impedance spectroscopy (EIS). New approaching ways are very useful to determine the mechanism of corrosion behavior more clearly for sintered steels of pure iron material and even Fe-Cu-C material that showed more complicated phenomena. Corrosion behavior of sintered steels of pure iron is correlated with density and that of Fe-Cu-C sintered steels is more complicated. Addition of copper and carbon accelerates cathodic reaction, but depolarization of anode reaction dominates corrosion speed among Fe-Cu-C materials.View full abstractDownload PDF (871K)
Special Issue:Magnetic Materials: Fabrication, Characterization, and Applications
Summarization
-
Masanori Abe2006 Volume 53 Issue 8 Pages 668
Published: 2006
Released on J-STAGE: January 30, 2007
JOURNAL OPEN ACCESSDownload PDF (71K)
Memorial Lecture of JSPM Award
-
Nobuji Suzuki2006 Volume 53 Issue 8 Pages 669-678
Published: 2006
Released on J-STAGE: January 30, 2007
JOURNAL OPEN ACCESSFor high quality and high resolution TV's and displays high-performance ferrite cores for deflection yokes are required. Therefore, I undertook fundamental research into the critical items in the ferrite manufacturing process including the starting raw materials, chemical compositions, additives, granulated powder, molding, sintering and microstructure control. Based on this knowledge, I have been able to develop manufacturing technology which has resulted in the industrial production of high-performance deflection yoke cores. In this paper, I describe iron oxide material, sintering technology (process and tools), spray drying method of powder granulation technology (featuring both fluidity improvement and reduction of the holes in the granulation powder) as well as a low loss core development. Moreover, I undertook a computer simulation and, based on the results of heat quantity analysis, I designed materials and succeeded in developing new material (DS1) in which the core loss and heat quantity have been dramatically reduced compared with conventional materials.View full abstractDownload PDF (2225K) -
Setsuo Yamamoto, Mitsuru Matsuura, Shigenobu Okada, Yoshihiro Shimosat ...2006 Volume 53 Issue 8 Pages 679-685
Published: 2006
Released on J-STAGE: January 30, 2007
JOURNAL OPEN ACCESSReactive sputtering apparatus utilizing electron cyclotron resonance (ECR) microwave plasma was developed for deposition of ferrite thin-films. High deposition rate of 44 nm/min. was achieved using a conic alloy target, and the deposited soft ferrite thin films successfully crystallized without heat treatment during film deposition and post annealing. Magnetic and physical properties for the films were analyzed in terms of saturation magnetization, coercivity, uniformity of film thickness, and inner stress. These properties were proved to be good enough as soft magnetic films. The result described that the oxygen partial pressure ratio to deposition rate strongly affected the magnetic properties. Well crystallized ultra thin (3-nm-thick) ferrite films were also successfully deposited on MgO(100) underlayer. These results imply that ECR sputtering method is one of the most effective deposition methods for highly crystallized polycrystalline thick and thin films. Low target voltage sputtering as low as −100 V successfully improved crystal orientation of the ferrite films by suppressing the affect of recoiled argon ion bombardment to the substrate.View full abstractDownload PDF (1027K) -
Yoshiyuki Shimada, Takao Nishioka, Akihiko Ikegaya2006 Volume 53 Issue 8 Pages 686-695
Published: 2006
Released on J-STAGE: January 30, 2007
JOURNAL OPEN ACCESSConventional soft magnetic materials used for various applications such as high-speed rotary motors were made by laminated steels. However, when these materials were used at high frequencies (1 kHz or higher), there was a decline in the magnetic properties caused by the core loss (heat generation by eddy current).
To solve these problems, we developed new soft magnetic materials made of fine magnetic iron powder coated with an insulating layer, to which ultra-trace volume of heat-resistant binder is added with high density, thus obtaining superior magnetic properties using the powder metallurgy (P/M) method.
This paper discussed on the DC and AC magnetic properties and the mechanical properties of newly developed P/M soft magnetic materials.View full abstractDownload PDF (1409K)
- |<
- <
- 1
- >
- >|