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Ōsaka, Japan

Yamamoto Y.,Daiken Chemical Co. | Yamamoto Y.,University of Fukui | Ogihara T.,University of Fukui
Key Engineering Materials | Year: 2010

Silver nanoparticles produced with a solid-phase thermal decomposition method were used for the preparation of a conductive paste supporting curing at low temperatures. The conducting paste was prepared by blending fine spherical silver powder and silver nanoparticles with a diameter of 20nm in order to reduce the electric resistivity of the electrodes. Although the viscosity of the conducting paste increased by about 25% after 60 days, it exhibited superior stability to dispersion in comparison to commercial paste. The electric resistivity of the electrode was of the order of 10 -6Ωcm at a curing temperature of 200° C. Using this conducting paste, it is possible to print at widths of 20μ m. The resistivity was further reduced by 1% in the high temperature test at 120° C, by 5% in the high humidity and high temperature test, and by 5% during the thermal shock test at temperatures ranging from -45 to 80° C. © (2010) Trans Tech Publications.

Okada A.,Daiken Chemical Co. | Okada A.,University of Fukui | Ogihara T.,University of Fukui
Key Engineering Materials | Year: 2010

Several types of Ag powder were used as electrode paste for a multilayer ceramic substrate. The shrinkage behavior of the silver powders was investigated during the sintering. Bending and cracking were frequently observed on the substrate when coarse powders that show a broad size distribution and aggregation were used. The shrinkage curve of the Ag paste obtained by spray pyrolysis agreed well with that of the substrate. Furthermore, the electrical properties of the Ag paste were also determined. The resistivity of a silver electrode sintered at 900°C was about 2.00×10-6 Ω·cm. © (2010) Trans Tech Publications.

Obata S.,Gifu Prefectural Ceramics Research Institute | Iwata Y.,Gifu Prefectural Ceramics Research Institute | Yokoyama H.,Gifu Prefectural Ceramics Research Institute | Sakurada O.,Gifu University | And 2 more authors.
Ceramic Transactions | Year: 2010

A water soluble titanate compound (TNB Lac) prepared by direct reaction of titanium tetra n butoxide (TNB) with lactic acid (Lac) in water showed characteristics of a polyanion and acted as a dispersant for preparing aqueous aluminum titanate (Al 2TiO 5) slurries. The isoelectric point of Al 2TiO 3 particles shifted to lower pH with increasing concentration of TNB Lac. The rheological behavior of aqueous Al 2TiO 5 slurries with TNB Lac was examined and evaluated. The dispersion and fluidity of aqueous Al 2TiO 5 slurry were enhanced by the addition of TNB Lac at pH 10, and the thickening limit of the well dispersed and fluidized slurry with 0.075 mmol g 1 TNB Lac was found at a solid content of 79 wt%. A high green density of 63% for the sintered powder was obtained through the slip casting process using slurries with 0.075 mmol g 1 TNB Lac. The maximum relative density value of the sintered bodies was 96.5% when the green body was fired at 1500°C. The sintered body had a homogeneous grain growth and dense microstructure without pores or abnormal grain growth.

Shigemune T.,Osaka University | Koizumi A.,Osaka University | Kashiwagi Y.,Osaka Municipal Technical Research Institute | Kakiuchi H.,Daiken Chemical Co. | And 12 more authors.
Zairyo/Journal of the Society of Materials Science, Japan | Year: 2015

We fabricated Ag electrodes on GaN-based blue light-emitting diodes (LEDs) by direct screen printing with Ag nanoparticle paste instead of commonly used dry processes. After the direct screen printing of Ag nanoparticle pastes on p-type GaN, successive sintering was carried out at 450°C for 30 min. LEDs with a square electrode size of 0.5 mm showed a threshold and operating voltage of 3.3 and 4.4 V, respectively. The maximum emission efficiency was obtained at 13 mA. These results suggest that screen printed Ag electrodes have a potential for use in GaN-based blue LEDs. © 2015 The Society of Materials Science, Japan.

Uruno H.,Toyohashi University of Technology | Oke S.,Tsuyama National College of Technology | Suda Y.,Toyohashi University of Technology | Takikawa H.,Toyohashi University of Technology | And 5 more authors.
IEEJ Transactions on Fundamentals and Materials | Year: 2010

RuO2 nanoparticles were supported on arc-black (AB) with different pH of Ru colloidal solutions. For lower pH, RuO2 particles in nanometer size were dispersed on AB, although for higher pH, RuO2 particles were aggregated. The RuO2-supported-AB prepared at pH 5 had the highest amount of RuO2 and showed the highest capacitance. © 2010 The Institute of Electrical Engineers of Japan.

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