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Professor:Keishi Nishio

In the most simple of terms ceramics are inorganic, nonmetallic materials. As ceramic technology has developed over time, the definition has expanded to include a much wider range of other compositions used in a variety of applications. Among ceramics, porcelains are used in electronics and other high-tech industries, so they must meet highly precise specifications and demanding performance requirements. Fine Ceramics are carefully engineered materials in which the chemical composition has been precisely adjusted using refined or synthesized raw powder, with a well-controlled method of forming and sintering. In our laboratory, raw fine powders are synthesized by chemical process like a sol-gel process, thermal decomposition method. And fine bulk ceramics are fabricated using Spark Plasma Sintering method (SPS).

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Example study

1

Thermoelectric (TE) power generation has recently attracted much interest as a technology for the conversion of heat into electricity. TE modules based on metal oxides have also been studied widely. However, there are few reports of such modules that have high-performance when compared to TE modules based on intermetallic compounds. We fabricated a π structure TE module with NaCo2O4 as the p-type leg and Mg2Si as the n-type leg by using the spark plasma sintering (SPS) method

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2

It is well known that tungsten tri-oxide (WO3) exhibits electrochromic and gasochromic properties. When Pt-nanoparticle-dispersed tungsten oxide (Pt-WO3) is exposed to hydrogen gas, the optical and electrical properties of the Pt-WO3 change drastically. Consequently, it is expected that thin films of WO3 can be applied as hydrogen gas leakage sensors. In our study, thin films of Pt-WO3 were prepared on glass substrates using a sol-gel process. The optical and electrical properties of the films were evaluated.

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3

ZrW2O8 demonstrate a large isotropic negative thermal expansion coefficient of -9 ppm/K which exists over a large range temperatures from 0.3 to 1050K. In our study, ZrW2O8 dense ceramics could be prepared by SPS method combined with sol-gel process by treated at 873K for 10min without decomposition to tungsten oxide and zirconium oxide. The obtained ceramics has high density above 90% and shows good negative thermal expansion coefficient.

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