US 8,076,256 B2 · Semiconductor ceramic composition and method for producing the same

Abstract

It is intended to provide a Pb-free semiconductor ceramic composition capable of shifting its Curie temperature toward a positive direction and capable of enhancing its jump characteristic while minimizing the increase in the resistivity at room temperature. There is provided a semiconductor ceramic composition in which a part of Ba of BaTiO3 is substituted with Bi—Na, the semiconductor ceramic composition being obtained by sintering a mixed calcined powder containing a calcined BT powder containing a calcined powder of (BaR)TiO3 or a calcined powder of Ba(TiM)O3 (in which R and M each are a semiconductor dopant), and a calcined BNT powder containing a calcined powder of (BiNa)TiO3; in which BaCO3 and/or TiO2 is/are added to the calcined BT powder or the calcined BNT powder or to the mixed calcined powder.

Claims6

Dependent claims

A BaTiO3 semiconductor ceramic composition in which a part of the Ba is substituted with Bi—Na, the semiconductor ceramic composition being represented by a composition formula:

[(BiNa)x(Ba1-yRy)1-x]TiO3, wherein R is at least one rare earth element and x and y each satisfy 0<x≦0.3 and 0<y≦0.02,
wherein the semiconductor ceramic composition is obtained by sintering a mixed calcined powder comprising a calcined powder of (BaR)TiO3, wherein R is at least one rare earth element), and a calcined powder of (BiNa)TiO3;
and
wherein BaCO3 and/or TiO2 is/are added to the calcined BT powder or the calcined BNT powder or to the mixed calcined powder, and the amount of BaCO3 and/or TiO2 added is such that the amount of BaCO3 is at most 30 mol % and the amount TiO2 is at most 30 mol % when the total amount of the calcined BT powder and BaCO3 and/or TiO2 is taken as 100 mol %.

1 more element

A method for producing a BaTiO3 semiconductor ceramic composition in which a part of the Ba is substituted with Bi—Na, in which the semiconductor ceramic composition is represented by a composition formula:

[(BiNa)x(Ba1-yRy)1-x]TiO3, wherein R is at least one rare earth element and wherein x and y each satisfy 0<x≦0.3 and 0<y≦0.02,
wherein the method comprises:
a step of preparing a calcined powder of (BaR)TiO3, wherein R is at least one rare earth element at a calcination temperature of not lower than 1000° C.,
a step of preparing a calcined powder of (BiNa)TiO3 at a calcination temperature within the range of 700° C. to 950° C.,
a step of mixing the calcined (BaR)TiO3 powder and the calcined (BiNa)TiO3 powder to prepare a mixed calcined powder,
and a step of forming and sintering the mixed calcined powder;
wherein BaCO3 and/or TiO2 is/are added to the calcined (BaR)TiO3 powder or the calcined (BiNa)TiO3 powder or to the mixed calcined powder, and the amount of BaCO3 and/or TiO2 added is such that the amount of BaCO3 is at most 30 mol % and the amount of TiO2 is at most 30 mol % when the total amount of the calcined BT powder and BaCO3 and/or TiO2 is taken as 100 mol %.

4 more elements

Dependencies are inferred from the claim text.

Semiconductor ceramic composition and method for producing the same

Life of this patent

Semiconductor ceramic composition and method for producing the same

Life of this patent

Abstract

Claims6