Agency of Industrial Science and Technology

Satoshi Sodeoka

Ryoji Funahashi

Ichiro Matsubara

Nobuyuki Tamari

Isao Kondou

Takahiro Tanaka

This invention provides a complex oxide comprising the features of : (i) being represented by the formula:(A B M ) Co O wherein A and B are elements differing from each other, each represents Ca, Sr or Ba, M represents Bi, Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb or Lu, 1.7&lE;x&lE;2, and 3.8&lE;y&lE;5, (ii) having a Seebeck coefficient of 100 &mgr;V/K or more at a temperature of 100 K (absolute temperature) or higher and (iii) having an electrical resistivity of 10 m&OHgr;cm or less at a temperature of 100 K (absolute temperature) or higher. The complex oxide of the invention is a material composed of low-toxicity elements existing in large amounts, the material having superior heat resistance and chemical durability and a high thermoelectric conversion efficiency in a temperature range of 600 K or higher which falls in the temperature range of waste heat.

Complex oxide having high thermoelectric conversion efficiency

This invention provides a complex oxide comprising the features of: (i) being represented by the formula: (A B M ) Co O wherein A and B are elements differing from each other, each represents Ca, Sr or Ba, M represents Bi, Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb or Lu, 1.7&lE;x&lE;2, and 3.8&lE;y&lE;5, (ii) having a Seebeck coefficient of 100 &mgr;V/K or more at a temperature of 100 K (absolute temperature) or higher and (iii) having an electrical resistivity of 10 m&OHgr;cm or less at a temperature of 100 K (absolute temperature) or higher. The complex oxide of the invention is a material composed of low-toxicity elements existing in large amounts, the material having superior heat resistance and chemical durability and a high thermoelectric conversion efficiency in a temperature range of 600 K or higher which falls in the temperature range of waste heat.

This invention provides a complex oxide comprising the features of: (i) being represented by the formula: Ca RE Co O wherein RE is a rare earth element, 0&lE;x&lE;0.5 and 8.5&lE;y&lE;10, (ii) having a Seebeck coefficient of 100 &mgr;V/K or more at a temperature of 300&deg; C. or higher, and (iii) having an electric conductivity of 10 S/m or more at a temperature of 300&deg; C. or higher. The complex oxide is composed of low-toxicity elements, excellent in heat resistance and chemical durability and high in thermoelectric conversion efficiency.

Complex oxide having high seebeck coefficient and high electric conductivity

There are disclosed a process for producing a uniformly mixed composite raw material for ceramics by recovering the uniformly mixed composite raw material for ceramics from the dispersion of at least two types of raw materials for ceramics and optionally a component other than said materials in a liquid medium, which comprises coagulating and precipitating the composite raw material together with aluminum hydroxide formed by reacting an aluminum salt with an alkali in the liquid medium; and a uniformly mixed composite raw material for ceramics which is produced by the above process.

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Ikeda, Japan

Satoshi Sodeoka