Compositions – Electrically conductive or emissive compositions – Metal compound containing
Reexamination Certificate
2011-08-09
2011-08-09
Kopec, Mark (Department: 1761)
Compositions
Electrically conductive or emissive compositions
Metal compound containing
C501S138000, C501S139000, C423S598000
Reexamination Certificate
active
07993547
ABSTRACT:
It is intended to provide a semiconductor ceramic composition in which a part of Ba in BaTiO3is substituted with Bi—Na, which is capable of restraining the evaporation of Bi in the calcination step, is capable of restraining the compositional deviation of Bi—Na thereby suppressing the formation of different phases, is capable of further reducing the resistivity at room temperature, and is capable of restraining the fluctuation of the Curie temperature; and to provide a production process of the same. When a calcined Ba(TiM)O3powder (M is a semiconductor dopant) and a calcined (BiNa)TiO3powder are separately prepared and the Ba(TiM)O3powder is calcined at a relatively high temperature while the (BiNa)TiO3powder is at a relatively low temperature, both at the most suitable temperatures for them, then the evaporation of Bi may be retarded and the compositional deviation of Bi—Na may be thereby suppressed to inhibit the formation of different phases; and when these calcined powders are mixed, formed and sintered, then a semiconductor ceramic composition which has a low resistivity at room temperature and is capable of restraining the fluctuation of the Curie temperature can be obtained.
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Shimada Takeshi
Toji Kazuya
Hitachi Metals Ltd.
Kopec Mark
Stein McEwen, LLP
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