High curie temperature ternary piezoelectric ceramics
View Patent ↗A preferred piezoelectric ceramic material is a BiFeO 3 —PbZrO 3 —PbTiO 3 ternary solid solution wherein proportions of the constituent perovskite metal oxides are selected so that the material exhibits relatively high Curie temperatures above 380° C. and useful piezoelectric properties.
1. A ceramic material comprising a ternary solid solution composition of BiFeO 3 —PbZrO 3 —PbTiO 3 represented by the following:
(1−x−y)BiFeO 3 -xPbZrO 3 -yPbTiO 3 where x is 0.02 to 0.28 while y is 0.26 to 0.36 and where x and y have different values and are selected such that the composition resides in a morphotropic phase boundary (MPB) region and the BiFeO 3 is present in a molar fraction greater than 50%.
2. The material of claim 1 wherein x is 0.053 and y is 0.299.
3. The material of claim 1 wherein x is 0.105 and y is 0.329.
4. The material of claim 1 wherein x is 0.161 and y is 0.333.
5. The material of claim 1 which is sintered.
6. A ceramic material comprising a ternary solid solution composition with BiFeO 3 , PbZrO 3 , and PbTiO 3 in proportions to provide a combination of piezoelectric properties and increased Curie temperature as compared to that of PZT wherein the proportions of PbZrO 3 , and PbTiO 3 are different, wherein the molar fraction of BiFeO 3 is greater than 50%, and wherein the composition resides within a morphotropic phase boundary (MPB) region.
7. The material of claim 6 having a Curie temperature exceeding 440° C.
8. The material of claim 7 wherein the Curie temperature is up to 575° C.
9. The material of claim 6 which is sintered.
10. A sensor, transducer, or actuator made of the material of claim 1 .
11. A sensor, transducer, or actuator made of the material of claim 6 .
12. A method of making a piezoelectric ceramic material, comprising mixing proportions of BiFeO 3 , PbZrO 3 , PbTiO 3 , calcining the mixture to make a ternary solid solution composition comprising BiFeO 3 , PbZrO 3 , and PbTiO 3 including selecting proportions of the BiFeO 3 , PbZrO 3 , and PbTiO 3 wherein the proportions of PbZrO 3 , and PbTiO 3 are different and wherein a molar fraction of BiFeO 3 is greater than 50% such that the ternary solid solution composition resides within a morphotropic phase boundary (MPB) region with a Curie temperature comparable to or increased as compared to that of PZT.
13. The method of claim 12 wherein the ceramic material is represented by the following:
(1−x−y)BiFeO 3 -xPbZrO 3 -yPbTiO 3 where x is 0.02 to 0.28 while y is 0.26 to 0.36 and wherein x and y have different values.
14. The method of claim 13 wherein x is 0.053 and y is 0.299.
15. The method of claim 13 wherein x is 0.105 and y is 0.329.
16. The method of claim 13 wherein x is 0.161 and y is 0.333.
17. The method of claim 12 including sintering the material.