Piezoelectric ceramic composition and piezoelectric ceramic electronic component

Abstract

A piezoelectric ceramic includes a main constituent represented by the general formula {(1−x) (K 1-a-b Na a Li b )(Nb 1-c Ta c )O 3 }−xM2M4O 3 }, and as accessory constituents, 2α mol of Na, (α+β) mole of an M4′ element, and γ mol of Mn with respect to 100 mol of the main constituent, where 0.1≦α≦β, 1≦α+β≦10, and 0≦γ≦10, M2 is Ca, Ba, and/or Sr, the M4 element and the M4′ element are Zr, Sn, and/or Hf, 0≦x≦0.06, 0≦a≦0.9, 0≦b≦0.1, and 0≦c≦0.3. Even in the case of using Ni as the main constituent in an internal electrode material of a piezoelectric element and carrying out co-firing, favorable piezoelectric properties can be obtained without defective polarization.

The invention claimed is: 
     
       1. A piezoelectric ceramic composition comprising
 a main constituent represented by the compositional formula
   {(1−x)(K 1-a-b Na a Li b )(Nb 1-c-d Ta c Sb d )O 3 }−xM2M4O 3 }
 
 
 
       wherein M2 is at least one member of the group consisting of Ca, Ba, and Sr, M4 is at least one member of the group consisting of Zr, Sn, and Hf, 0≦x≦0.06, 0≦a≦0.9, 0≦b≦0.1, 0≦c≦0.3, and 0≦d≦0.05, and
 as accessory constituents, 2α mol of Na, (α+β) mol of M4′, γ mol of Mn and δ mol of M3, with respect to 100 mol of the main constituent, wherein 
 M4′ is at least one member of the group consisting of Zr, Sn, and Hf, M3 is at least one member selected from the group of Sc, In, Yb, Y, Nd, Eu, Gd, Dy, Sin, Ho, Er, Tb, Lu, La, and Pr, 0.1≦α≦β, 1≦α+β≦10, 0≦γ≦10, and 0≦δ≦5. 
 
     
     
       2. The piezoelectric ceramic composition according to  claim 1 , wherein 2≦γ≦10. 
     
     
       3. The piezoelectric ceramic composition according to  claim 2 , wherein 0.001≦x≦0.06. 
     
     
       4. The piezoelectric ceramic composition according to  claim 3 , wherein 0<d. 
     
     
       5. The piezoelectric ceramic composition according to  claim 4 , wherein 0<δ. 
     
     
       6. The piezoelectric ceramic composition according to  claim 5 , wherein 0.1≦δ. 
     
     
       7. The piezoelectric ceramic composition according to  claim 6 , wherein M3 is at least one member selected from the group of Yb, Y, Nd, Eu, Gd, Dy, Sm, Ho, Er, Tb, Lu, and Pr. 
     
     
       8. The piezoelectric ceramic composition according to  claim 1 , wherein 0.001≦x≦0.06. 
     
     
       9. The piezoelectric ceramic composition according to  claim 1 , wherein 0<d. 
     
     
       10. The piezoelectric ceramic composition according to  claim 1 , wherein 0<δ. 
     
     
       11. A piezoelectric ceramic electronic component comprising
 a sintered piezoelectric ceramic body comprising internal electrodes and piezoelectric ceramic layers stacked alternately; and 
 at least two external electrodes on a surface of the piezoelectric ceramic body, 
 wherein the piezoelectric ceramic layers comprise the piezoelectric ceramic composition according to  claim 9 . 
 
     
     
       12. The piezoelectric ceramic electronic component according to  claim 11 , wherein the internal electrodes comprise Ni as their main constituent. 
     
     
       13. A piezoelectric ceramic electronic component comprising
 a sintered piezoelectric ceramic body comprising internal electrodes and piezoelectric ceramic layers stacked alternately; and 
 at least two external electrodes on a surface of the piezoelectric ceramic body, 
 wherein the piezoelectric ceramic layers comprise the piezoelectric ceramic composition according to  claim 8 . 
 
     
     
       14. The piezoelectric ceramic electronic component according to  claim 13 , wherein the internal electrodes comprise Ni as their main constituent. 
     
     
       15. A piezoelectric ceramic electronic component comprising
 a sintered piezoelectric ceramic body comprising internal electrodes and piezoelectric ceramic layers stacked alternately; and 
 at least two external electrodes on a surface of the piezoelectric ceramic body, 
 wherein the piezoelectric ceramic layers comprise the piezoelectric ceramic composition according to  claim 7 . 
 
     
     
       16. The piezoelectric ceramic electronic component according to  claim 15 , wherein the internal electrodes comprise Ni as their main constituent. 
     
     
       17. A piezoelectric ceramic electronic component comprising
 a sintered piezoelectric ceramic body comprising internal electrodes and piezoelectric ceramic layers stacked alternately; and 
 at least two external electrodes on a surface of the piezoelectric ceramic body, 
 wherein the piezoelectric ceramic layers comprise the piezoelectric ceramic composition according to  claim 2 . 
 
     
     
       18. The piezoelectric ceramic electronic component according to  claim 17 , wherein the internal electrodes comprise Ni as their main constituent. 
     
     
       19. A piezoelectric ceramic electronic component comprising
 a sintered piezoelectric ceramic body comprising internal electrodes and piezoelectric ceramic layers stacked alternately; and 
 at least two external electrodes on a surface of the piezoelectric ceramic body, 
 wherein the piezoelectric ceramic layers comprise the piezoelectric ceramic composition according to  claim 1 . 
 
     
     
       20. The piezoelectric ceramic electronic component according to  claim 19 , wherein the internal electrodes comprise Ni as their main constituent. 
     
     
       21. A piezoelectric ceramic electronic component comprising a sintered piezoelectric ceramic body comprising internal electrodes and piezoelectric ceramic layers stacked alternately; and at least two external electrodes on a surface of the piezoelectric ceramic body,
 wherein the piezoelectric ceramic layers contain a main constituent and an accessory constituent, the accessory constituent contains 2α mol of Na with respect to 100 mol of the main constituent, and wherein molar content of respective elements constituting piezoelectric ceramic layers are represented by:   x=Σ(Ca,Ba,Sr)/(Σ(Nb,Ta,Sb,Ca,Ba,Sr),   a=1−(Σ(Li)/(Σ(Nb,Ta,Sb)−(Σ(K)/(Σ(Nb,Ta,Sb)),   b=Σ(Li)/Σ(Nb,Ta,Sb),   c=Σ(Ta)/Σ(Nb,Ta,Sb),   d=Σ(Sb)/Σ(Nb,Ta,Sb),   α=50×(Σ(K,Na,Li))/Σ(Nb,Ta,Sb,Ca,Ba,Sr)−Σ(Nb,Ta,Sb)/Σ(Nb,Ta,Sb,Ca,Ba,Sr)),   α+β=100×(Σ(Zr,Sn,Hf)/Σ(Nb,Ta,Sb,Ca,Ba,Sr)−Σ(Ca,Ba,Sr)/Σ(Nb,Ta,Sb,Ca,Ba,Sr)),   γ=100×(Σ(Mn)/Σ(Nb,Ta,Sb,Ca,Ba,Sr)), and   δ=100×(Σ(Sc,In,Yb,Y,Nd,Eu,Gd,Dy,Sm,Ho,Er,Tb,Lu,La,Pr)/Σ(Nb,Ta,Sb,Ca,Ba,Sr)),   in which Σ( . . . ) indicates the total of moles of the elements within the brackets ( ),   0.001≦x≦0.06,   0≦a≦0.9,   0≦b≦0.1,   0≦c≦0.3,   0≦d≦0.05,   0.1≦α≦β,   1≦α+β≦10,   0≦γ≦10, and   0≦δ≦5.   
     
     
       22. The piezoelectric ceramic electronic component according to claim 21, wherein the internal electrodes comprise Ni as their main constituent.