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Volume 51, Issue 11
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[in Japanese]2004 Volume 51 Issue 11 Pages 776
Published: November 15, 2004
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSDownload PDF (108K) -
Satoru Ohno, Hideo Okuyama, Sakka Yoshio2004 Volume 51 Issue 11 Pages 777-788
Published: November 15, 2004
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSNanoparticle processing is noticed as one of the key technology which supports the progress of the nanotechnology in recent years. In this paper, outline of "Reactive plasma-liquid phase" reaction method which is nanoparticle preparation method using DC arc plasma, examples of various nanoparticles prepared by this method, and characteristics of theire nanoparticles were described. Especially in these nanoparticles, the composite nanoparticle of metal-non oxide system in which multiple materials combined in the nano region, showed a unique characteristic that the nanoparticles of single composition never show.View full abstractDownload PDF (6825K) -
Singto Sakulkhaemaruethai, Yoshikazu Suzuki, Susumu Yoshikawa2004 Volume 51 Issue 11 Pages 789-794
Published: November 15, 2004
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSMesoporous anatase-type ZrO2-doped TiO2 nanocrystals have been prepared via a surfactant-assisted templating method (SATM). The ZrO2-doped TiO2 nanocrystals had high phase stability and maintained anatase structure even calcining at 800 °C for 4 h. The ZrO2 dopants present in this system showed inhibitory effect not only to the phase transformation from anatase to ruitle phase, but also to the crystallite growth of TiO2.View full abstractDownload PDF (1753K) -
Yukio Takada, Takuya Nishio, Takashi Nakagawa, Takao A. Yamamoto, Sato ...2004 Volume 51 Issue 11 Pages 795-801
Published: November 15, 2004
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSWe successfully synthesized M-(BaFe12O19) and Co2Y-type (Ba2Co2Fe12O22) hexagonal ferrite nanoparticles by the technique of ultrasonic spray pyrolysis. Starting solution was a mixture of iron, barium and cobalt nitrates and deionized water with stoichiometric composition of hexaferrites. The products were collected by use of an electrostatic precipitator. Effects of temperature and gas-flow rate on occurring phase and grain morphology were investigated. The product was characterized with XRD and SEM experiments. Single phase materials of these hexaferrites with particle size of 100 nm-1μm were obtained at lower temperature. These experiments indicate that the gas-flow rate influences on the formation temperature and that the temperature in heating zone affects grain morphology of resultant particles.View full abstractDownload PDF (3073K) -
Masateru Nose, Hirofumi Suzuki, Yoshio Okumura, Eiji Honbo, Takehiko M ...2004 Volume 51 Issue 11 Pages 802-807
Published: November 15, 2004
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe influence of sputtering conditions on the microstructure and mechanical properties of Ti-Al-Si-N was investigated using XRD, XPS and ultra-microindentaion. The targets of Ti50Al50 and Ti50Al40Si10 alloy were sputtered in a mixture of argon and nitrogen using an r.f. sputtering apparatus of Facing Target-type Sputtering. The substrate was heated up to -573 K and a substrate bias of d.c. up to -100 V was applied. XRD patterns of Ti-Al-Si-N films suggested two phases, the cubic B1 NaCl type structure and an amorphous phase, were presented in the film. XRD and XPS results indicate that the Ti-Al-Si-N films have a nano-composite structure consisting of nanocrystalline Ti(Al)N and amorphous phase. The highest hardness of 43 GPa was obtained for the Ti-Al-Si-N films deposited at 573 K without substrate bias. This hardness is -19% higher than that for Ti-Al-N films. On the other hand, Young's modulus for Ti-Al-Si-N films was 360 GPa, which is -13% lower than that of Ti-Al-N films. When the substrate bias of -30 V was applied for Ti-Al-Si-N film deposition, h-AMN peak was detected in the XRD pattern and the hardness of the film decreased. These results could be attributed to the segregation of h-AlN phase from the Ti-Al-Si-N nano-composite films.View full abstractDownload PDF (441K) -
Masateru Nose, Hirofumi Suzuki, Yoshio Okumura, Eiji Honbo, Takehiko M ...2004 Volume 51 Issue 11 Pages 808-814
Published: November 15, 2004
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe influence of Si addition on the microstructure, mechanical properties and oxidation resistance of Ti-Al-Si-N was investigated using XRD, XPS, SEM and ultra-microindentaion. The composite targets consisting of a Ti50Al50 plate and Si chips were sputtered in a mixture of argon and nitrogen. Ti-Al-Si-N films were prepared in an r.f. sputtering apparatus of the Facing Target-type Sputtering. During the deposition, the substrate was heated from room temperature up to -573 K without substrate bias application. The total results of XRD, XPS and SEM revealed that the Ti-Al-Si-N films have a nano-composite structure consisting of nanocrystalline Ti-Al-N and an amorphous phase containing Si3N4. The highest hardness of 38 GPa was obtained for films with 3.5%Si. The films were subjected to an oxidation test, where they were exposed to a temperature in the range of 873 K to 1193 K for 1 ks. The hardness of Ti-Al-Si-N films hardly decreased after oxidation test up to 973 K, whereas the hardness of Ti-Al-N films decreased 7% at 973 K. Only a small TiO2 peak was observed for the Ti-Al-Si-N films oxidized at 973 K, whereas many TiO2 peaks were observed in the Ti-Al-N film. SEM & EDS observation revealed that the inside of the Ti-Al-Si-N film was not oxidized even after oxidation test at 1193 K. These improvements of Ti-Al-Si-N films could be attributed to the formation of nano-composite structure.View full abstractDownload PDF (2987K) -
Akihiko Suda, Kae Yamamura, Sobukawa Hideo, Yoshio Ukyo, Toshitaka Tan ...2004 Volume 51 Issue 11 Pages 815-820
Published: November 15, 2004
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSCeria-zirconia (Ce-Zr) solid solution is widely used as an oxygen storage material, which is a key component in the automotive three-way catalysts. The Ce-Zr solid solution is usually used with noble metals supported on their surface. Thus the evaluation of oxygen storage capacity (OSC) should be conducted on the Ce-Zr solid solution loaded with a noble metal. The measured OSC of noble-metal-loaded Ce-Zr solid solution consists of two parts; one is the stored oxygen within the solid solution itself, and the other is the adsorbed oxygen on the surface of the supported noble metal particles. Therefore, it is necessary to clarify the influence of the noble metal on the measured OSC, and this will also help to ascertain the exact OSC of the solid solution itself. In this research, the authors tried to clarify the above issues by characterizing the OSC performance on Ce-Zr solid solutions with Pt loading from 0.0001 to 10 wt%. We found that, increasing the Pt loading makes the oxygen storage and release rate higher. Temperature increase also makes the oxygen storage rate higher, however, the oxygen release rate is not affected by the temperature. The apparent OSC saturated above a certain level of Pt loading and temperature. The saturated OSC increased with increasing temperature.View full abstractDownload PDF (517K) -
Takashi Goto, Teiichi Kimura, Rong Tu2004 Volume 51 Issue 11 Pages 821-828
Published: November 15, 2004
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSZirconia is commonly used for thermal barrier coatings (TBCs) because of excellent mechanical and thermal properties. While practical high-speed deposition processes such as atmospheric plasma spray (APS) and electron-beam physical vapor deposition (EB-PVD) have been employed in TBCs, chemical vapor deposition (CVD) has been regarded to be inappropriate due to low deposition rates. However, we have successfully achieved highest deposition rates of 108 and 660μm h-1 with conventional MOCVD and newly developed laser CVD, respectively. The high-speed CVDs are significantly effective to improve the thermal barrier characteristics by the formation of nanopores in columnar zirconia grains. The laser CVD is also applicable for the extremely high-speed deposition of other oxides, such as Y2O3, TiO2 and Al2O3, at deposition rates around 2 to 3 mm h-1.View full abstractDownload PDF (7505K)
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