Piezoelectric ceramic material, method for the production thereof, and multilayer component
View Patent ↗A piezoelectric ceramic material has the general formula: P 1-c-d D c Z d (PbO) w where: 0<c≦0.025; 0≦d≦0.05; 0≦w≦0.05; where P stands for a compound having the formula [Pb 1-v Ag I v ][(Zr 1-y Ti y ) 1-u Cu II u ]O 3 , where 0.50≦1−y≦0.60; 0<u≦0.0495; 0≦v≦0.02, and D stands for a component of the general formula [(M 1 O) 1-p (M 2 O) p ] a [Nb 2 O 5 ] 1-a , where M 1 stands for Ba 1-t Sr t , where 0≦t≦1, M 2 stands for Sr and/or Ca, and 0<p<1 and ⅔<a<1 and Z stands for a compound of the general formula: Pb(L 1 R r )O 3 where L is present in the oxidation state II or III, and R is present in the oxidation state VI or V, and: L II is selected from among Fe, Mg, Co, Ni and Cu in combination with R VI =W, where 1=½ and r=½, or L III is selected from among Fe, Cr and Ga in combination with R V =Nb, Ta or Sb, where 1=½ and r=½, or L III is selected from among Fe, Cr and Ga in combination with R VI =W, where 1=⅔ and r=⅓.
1. A piezoelectric ceramic material of the general formula:
P 1-c-d D c Z d (PbO) w
where:
0<c≦0.025; 0≦d≦0.05; 0≦w≦0.05;
wherein P is a compound of the formula [Pb 1-v Ag I v ][(Zr 1-y Ti y ) 1-u Cu II u ]O 3 , where 0.50≦1−y≦0.60; 0<u≦0.0495; 0≦v≦0.02, and
D is a component of the general formula
[(M 1 O) 1-p (M 2 O) p ] a [Nb 2 O 5 ] 1-a
where
M 1 is Ba 1-t Sr t , where 0≦t≦1,
M 2 is Sr and/or Ca, and
0<p<1 and ⅔<a<1, and
Z is a compound of the general formula:
Pb(L 1 R r )O 3
where
L is present in the oxidation state II or III and R is in the oxidation state VI or V, and
L II is selected from among Fe, Mg, Co, Ni and Cu in combination with R VI =W,
where
1=½ and r=½, or
L III is selected from among Fe, Cr and Ga in combination with R V =Nb, Ta or Sb,
where
1=½ and r=½, or
L III is selected from among Fe, Cr and Ga in combination with R VI =W, where 1=⅔ and r=⅓.
2. The ceramic material according to claim 1 , wherein the compound P serves as host lattice for the further components, and can be described by the general formula of the perovskite lattice ABO 3 .
3. The ceramic material according to claim 1 , wherein u obeys: 0<u≦0.015.
4. The ceramic material according to claim 1 , wherein v obeys: 0<v≦0.010.
5. The ceramic material according to claim 1 , wherein v obeys: v=0.
6. The ceramic material according to claim 1 , wherein t=1 and M 2 is Sr.
7. The ceramic material according to claim 1 , wherein Z is Ba(Cu 0.5 W 0.5 )O 3 .
8. The ceramic material according claim 1 , wherein L comprises an element selected from the group consisting of Fe, Mg, Co, Ni, Cr, Li and combinations thereof.
9. A piezoelectric multilayer component comprising:
internal electrodes comprising at least one element selected from the group consisting of Ag, Pd, and Cu; and
a plurality of ceramic layers adjacent the internal electrodes, each ceramic layer comprising a ceramic material according to claim 1 .
10. A process for producing a piezoelectric ceramic material, the process comprising comminuting and mixing a plurality of starting materials to form a mixture,
forming green sheets from the mixture, and
sintering the green sheets,
wherein the piezoelectric ceramic material comprises the general formula:
P 1-c-d D c Z d (PbO) w
where: 0<c≦0.025; 0≦d≦0.05; 0≦w≦0.05;
wherein P is a compound of the formula [Pb 1-v Ag I v ][(Zr 1-y Ti y ) 1-u Cu II u ]O 3 , where 0.50≦1−y≦0.60; 0<u≦0.0495; 0≦v≦0.02, and
D is a component of the general formula
[(M 1 O) 1-p (M 2 O) p ] a [Nb 2 O 5 ] 1-a
where
M 1 is Ba 1-t Sr t , where 0≦t≦1,
M 2 is Sr and/or Ca, and
0<p<1 and ⅔<a<1, and
Z is a compound of the general formula:
Pb(L 1 R r )O 3
where
L is present in the oxidation state II or III and R is in the oxidation state VI or V, and
L III is selected from among Fe, Mg, Co, Ni and Cu in combination with R VI =W,
where
1=½ and r=½, or
L III is selected from among Fe, Cr and Ga in combination with R V =Nb, Ta or Sb,
where
1=½ and r=½, or
L III is selected from among Fe, Cr and Ga in combination with R VI =W, where 1=⅔ and r=⅓.
11. The process according to claim 10 , wherein the Cu from CuO and/or Cu 2 O is incorporated as Cu II into the ceramic material during sintering.
12. The process according to claim 11 , wherein oxygen vacancies are formed in the ceramic material by incorporation of Cu II into the ceramic material, so that an intermediate having the general formula:
Pb[(Zr 1-y Ti y ) 1-u Cu II u ]O 3-u V O;u ,
where V O is an oxygen vacancy and: 0<u≦0.0495, is formed in the process.
13. The process according to claim 12 , wherein Ag 2 O is used as further starting material and the Ag is incorporated as Ag I into the ceramic material during sintering, so that an intermediate having the general formula:
[Pb 1-v Ag I v ][(Zr 1-y Ti y ) 1-u Cu II u ]O 3-u+0.5v V O;u-0.5v ,
where:
0<v≦0.02, is formed in the process.
14. The process according to claim 12 , wherein the oxygen vacancies are filled by oxygen from air during cooling after sintering.
15. The process according to claim 12 , wherein the volume diffusion during the sintering process is increased by the oxygen vacancies.