Compositions for high power piezoelectric ceramics

Abstract

A class of ceramic compositions according to the formula Pb (1-z) M z (Mn 1/3 Sb 2/3 ) x (Zr y Ti 1-y ) 1-x O 3 where M is selected to be either Sr or Ba, x is selected to be between 0.01 and 0.1, y is selected to be between 0.35 and 0.55, and z is selected to be between 0.01 and 0.10. In some embodiments of the above composition, one or more dopants is added to the compositions. The dopant(s) may be selected from the group comprising: PbO, CeO 2 , SnO 2 , Sm 2 O 3 , TeO 2 , MoO 3 , Nb 2 O 5 , SiO 2 , CuO, CdO, HfO 2 , Pr 2 O 3 , and mixtures thereof. The dopants can be added to the ceramic composition in individual amounts ranging from 0.01 wt % to up to 5.0 wt %. The preferred ceramic compositions exhibit one or more of the following electromechanical properties: a relative dielectric constant (∈) of between 1200 and 2000, a mechanical quality factor (Q m ) of between 1500 and 2800; a piezoelectric strain constant (d 33 ) of between 250-450 pC/N, a dielectric loss factor (tan δ) of between 0.002-0.008 and a thickness electromechanical coupling coefficient (k t ) of between 0.45 and 0.7.

1 . A PZT ceramic material made by combining oxides of Pb, Sr, Mn, Sb, Zr, and Ti according to the following formula:
   Pb x Sr (1-x) (Mn 1/3 Sb 2/3 ) (1-y) (Zr z Ti 1-z ) y O 3      
       wherein x is about 0.96; 
       wherein y is about 0.94; and 
       wherein z is about 0.5; and 
       wherein the material further includes dopants in the amounts of: 
       CeO 2  is about 0.4%; 
       CuO is about 1%; and 
       Nb 2 O 5  is about 4%. 
     
     
         2 . A PZT ceramic material made by combining oxides of Pb, Sr, Mn, Sb, Zr, and Ti according to the following formula:
   Pb x Sr (1-x) (Mn 1/3 Sb 2/3 ) (1-y) (Zr z Ti 1-z ) y O 3      
       wherein x is in the range of 0.95 to 0.99; 
       wherein y is in the range of 0.92 to 0.97; and 
       wherein z is in the range of 0.45 to 0.55;
 wherein said composition further includes one or more dopants selected from the group consisting of: PbO, CeO 2 , SnO 2 , Sm 2 O 3 , TeO 2 , MoO 3 , Nb 2 O 5 , SiO 2 , CuO, CdO, HfO 2 , Pr 2 O 3 , and mixtures thereof. 
 
     
     
         3 . A composition according to  claim 2  wherein the total amount of said dopant(s) is between 1.0% and 4.0% by weight. 
     
     
         4 . A PZT-type piezoelectric ceramic composition made by combining oxides of Pb, Sr, Mn, Sb, Zr, Ti and Ce in the following relative amounts:
   Pb 0.98 Sr 0.02 Mn 0.016 Sb 0.03 Zr 0.48 Ti 0.47 Ce 0.004 .   
     
     
         5 . A PZT-type piezoelectric ceramic composition made by combining oxides of Pb, Sr, Mn, Sb, Zr, Ti, Ce and Cu in the following relative amounts:
   Pb 0.98 Sr 0.02 Mn 0.016 Sb 0.03 Zr 0.48 Ti 0.47 Ce 0.004 Cu 0.006 .   
     
     
         6 . A PZT-type piezoelectric ceramic composition made by combining oxides of Pb, Sr, Mn, Sb, Zr, Ti, Ce, Cu and Nb in the following relative amounts:
   Pb 0.96 Sr 0.02 Mn 0.016 Sb 0.03 Zr 0.47 Ti 0.46 Ce 0.004 Cu 0.006 Nb 0.004 .   
     
     
         7 . A PZT-type piezoelectric ceramic composition made by combining oxides of Pb, Sr, Mn, Sb, Zr, Ti, Ce, Cu and Nb in the following relative amounts:
   Pb 0.96 Sr 0.02 Mn 0.016 Sb 0.03 Zr 0.47 Ti 0.46 Ce 0.004 Cu 0.01 Nb 0.04 .   
     
     
         8 . A PZT-type piezoelectric ceramic composition made by combining oxides of Pb, Sr, Mn, Sb, Zr, Ti, Ce, Cu, Nb and Sn in the following relative amounts:
   Pb 0.96 Sr 0.02 Mn 0.016 Sb 0.03 Zr 0.47 Ti 0.46 Ce 0.004 Cu 0.002 Nb 0.04 Sn 0.004 .