Murata Manufacturing Co., Ltd.

Isamu Yoshizawa

Katsuhiro Horikawa

Akira Ando

Koichi Hayashi

A piezoelectric ceramic material is provided which can form a sintered piezoelectric ceramic compact having a low electromechanical coupling coefficient, a low resonant resistance and a low temperature dependence of the resonant frequency. The piezoelectric ceramic material is a solid solution having a primary component composed of PbTiO , PbZrO and Pb(Ma Md )O , in which Ma is at least one bivalent element or trivalent element, and Md is at least one pentavalent element or hexavalent element, and the ratio X/Y of the Ma content X to the Md content Y is larger than the stoichiometric ratio. Preferred is Ma being Mn, Md being at least one of Nb, Sb, Ta and W, and when the contents of Mn, Nb, Sb, Ta and W are represented by A, B, C, D and E, respectively, 0.525&lE;A/(B&plus;C&plus;D&plus;2E)&lE;1, and about 20 mole percent or less of the element Pb being replaced by at least one of Ca, Ba, Sr and La. Preferably, a sintered compact is obtained by firing this piezoelectric ceramic material in an oxygen atmosphere at an oxygen concentration of about 80% by volume or more is used in an unsaturated polarized state having an electromechanical coupling coefficient corresponding to about 80% or less of that of a sintered compact in a saturated polarized state.

Piezoelectric ceramic material, sintered piezoelectric ceramic compact, and piezoelectric ceramic device

A piezoelectric ceramic material able to form a piezoelectric ceramic sintered body having such characteristics as a small electromechanical coupling coefficient, small resonant resistance and small temperature dependency of the resonant frequency that is required for designing a narrow-band filter is represented by principal component of the general formula of (Pb,Sr,)(Zr,Ti,Mn,Nb,)O,and having a composition satisfying the following relations of 0.93&lE;a&lE;1.01, 0.01&lE;b&lE;0.04, 0.37&lE;c&lE;0.47, 0.48&lE;d&lE;0.58, 0.0105&lE;e&lE;0.06, 0.02&lE;f&lE;0.06 and 1.05&lE;2e/f&lE;2, and comprising sub-components of about 0.003% to 0.1% by weight of each of SiO,and Al,O,relative to the principal component.

Piezoelectric ceramic material and piezoelectric ceramic sintered body obtained using the same

Provided is a piezoelectric ceramic composition containing a lead titanate which has excellent temperature stability of the resonance frequency, and is suitable for application in a filter, a vibrator or the like, and a piezoelectric element using the piezoelectric ceramic composition. A piezoelectric substrate comprising a ceramic material containing PbTiO.sub.3 is provided with vibrating electrodes on the front and rear surfaces. The ceramic material containing PbTiO.sub.3 contains not less than about 0.1% by weight or more than about 3.0% by weight of Mn based on MnCO.sub.3 as the subcomponent in the main component having a composition satisfying 0.02.ltoreq.x.ltoreq.0.16 and 0.15.ltoreq.y.ltoreq.0.50 of the general formula Pb.sub.1-1.5x Nd.sub.x [(In.sub.1/2 Nb.sub.1/2).sub.y Ti.sub.1-y ]O.sub.3.

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Omihachiman, Japan

Isamu Yoshizawa