Crystal oriented ceramics and method of manufacturing the same, crystal-oriented ceramic production for the plate-like powder, and thermoelectric conversion element

摘要

PROBLEM TO BE SOLVED: To provide a crystal-oriented ceramic which comprises a cobalt-layered oxide showing thermoelectric properties and has high figure of merit, and to provide its production method, a plate-shaped powder for producing the crystal- orientated ceramic, and a thermoelectric transducer using the same. ;SOLUTION: The crystal-orientated ceramic comprises a cobalt-layered oxide, preferably a polycrystal of a calcium-cobalt layered oxide expressed by a general formula: {(Ca_1-xA_x)₂CoO_3+α}(CoO_2+β)_y (wherein A is one or more element selected from among alkali metal, alkaline earth metal and Bi; and 0≤x≤0.3, 0.5≤y≤2.0, 0.85≤{3+α+(2+β)y}/(3+2y)≤1.15), and it is characterized in that each crystal grain composing the polycrystal has a degree of {001} plane orientation of 50% or more. These crystal-oriented ceramics can be obtained by molding mixture of layered oxide-producing raw materials such as Co(OH)₂ plate- shaped powders and CaCO₃ so as to orient the plate-shaped powders, and by heating at a predetermined temperature.;COPYRIGHT: (C)2003,JPO