Piezoelectric ceramic, piezoelectric element comprising it, and piezoelectric device comprising piezoelectric element
View Patent ↗According to a preferred embodiment, the piezoelectric ceramic includes a complex oxide having the composition represented by formula (1) or (2), and Mn at 0.2-1.2 mass % or 0.2-3 mass %, respectively, in terms of MnCO 3 . (Pb 1-a A 1 a )Ti x Zr 1-x-y-z-b (Zn 1/3 A 2 2/3 ) y (Yb 1/2 A 2 1/2 ) z Sn b O 3 (1) (Pb 1-a A 1 a )Ti x Zr 1-x-y-b (Zn 1/3 A 2 2/3 ) y Sn b O 3 (2) [In formula (1), A 1 represents at least one element selected from the group consisting of Ca, Sr and Ba, and A 2 is at least one element selected from the group consisting of Nb, Ta and Sb, and includes at least Nb. In formula (2), A 1 represents at least one element selected from among Ca, Sr and Ba, A 2 represents at least one element selected from among Nb and W, and A 2 includes at least Nb.]
1. A piezoelectric ceramic comprising a complex oxide having the composition represented by formula (1), and Mn,
wherein the Mn content with respect to the total amount of complex oxide is 0.2-1.2 mass % in terms of MnCO 3 ,
(Pb 1-a A 1 a )Ti x Zr 1-x-y-z-b (Zn 1/3 A 2 2/3 ) y (Yb 1/2 A 2 1/2 ) z Sn b O 3 (1)
[In formula (1), A 1 represents at least one element selected from the group consisting of Ca, Sr and Ba, A 2 represents at least one element selected from the group consisting of Nb, Ta and Sb and includes at least Nb, and a, b, x, y and z are values satisfying formulas (1a), (1b), (1x), (1y) and (z), respectively,]
0≦ a≦ 0.04 (1a)
0≦ b≦ 0.04 (1b)
0.40≦ x≦ 0.49 (1x)
0.03≦ y≦ 0.15 (1y)
0.03≦ z≦ 0.15 (1z).
2. The piezoelectric ceramic according to claim 1 , wherein A 2 includes Nb and at least one element selected from the group consisting of Ta and Sb.
3. A piezoelectric ceramic comprising:
a complex oxide represented by formula (2), and
Mn,
wherein the Mn content in terms of MnCO 3 is 0.2-3 mass % with respect to the complex oxide,
(Pb 1-a A 1 a )Ti x Zr 1-x-y-b (Zn 1/3 A 2 2/3 ) y Sn b O 3 (2)
[In formula (2), A 1 represents at least one element selected from among Ca, Sr and Ba, A 2 represents at least one element selected from among Nb and W, and A 2 includes at least Nb also, a, x, y and b are values satisfying formulas (2a), (2x), (2y) and (2b), respectively,]
0≦ a≦ 0.04 (2a)
0.4≦ x≦ 0.48 (2x)
0.03≦ y≦ 0.2 (2y)
0.02≦ b≦ 0.04 (2b).
4. The piezoelectric ceramic according to claim 3 , wherein A 2 includes Nb and W.
5. A piezoelectric element comprising the piezoelectric ceramic according to claim 1 .
6. A piezoelectric element comprising the piezoelectric ceramic according to claim 3 .
7. A piezoelectric device comprising the piezoelectric element according to claim 5 .
8. A piezoelectric device comprising the piezoelectric element according to claim 6 .