Piezoelectric ceramic composition and piezoelectric element
AssigneeMurata Manufacturing Co., Ltd.
InventorsTomoyuki Ogawa, Katsuhiro Horikawa, Toshikatsu Hisaki
Life of this patent
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Abstract
A piezoelectric ceramic composition is expressed by the formula Pbα[{Niw/3Nb1−(w/3)}xTiyZrz]O3. The B site variables x, y, and z lie in a predetermined region in a ternary diagram. The Ni—Nb molar proportion variable satisfies the relationship 0.85≦w<1.00. The Pb molar content α is reduced from the stoichiometric ratio to a value satisfying the relationship 0.950≦α≦0.995. At least one element selected from the group consisting of Sr, Ca, and Ba may be substituted for about 10 mol percent of the Pb.
Claims19
A piezoelectric ceramic composition comprising Pb, Ni, Nb, Ti, Zr and O, the composition being expressed by the formula
- PbβMγ[{Niw/3Nb1−(w/3)}xTiyZrz]O3
- wherein M is at least one element selected from the group consisting of Sr, Ca and Ba, γ is 0 to about 0.1, γ and β satisfy the relationships:
- γ≦0.10 and 0.950≦β+γ≦0.995, x, y, and z lie on the lines connecting points A, B, C and D in a ternary diagram or within the region surrounded by the lines, w satisfies the relationship 0.85≦w<1.00, and α is β+γ and is lower than the stoichiometric ratio, and wherein points A, B, C, and D are:
- A:
- (x, y, z)=(0.10, 0.42, 0.48);
- B:
- (x, y, z)=(0.10, 0.48, 0.42);
- C:
- (x, y, z)=(0.40, 0.39, 0.21);
- and
- D:
- (x, y, z)=(0.40, 0.33, 0.27).
Dependencies are inferred from the claim text.