Electrostrictive ceramic material including a process for the preparation thereof and applications thereof

Claim 2

An electrostrictive ceramic composition consisting essentially of a solid solution of lead magnesium niobate, lead titanate and at least one dopant selected from the group consisting of barium titanate and strontium titanate, said composition being defined by the following formula: (W)Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3.(X)PbTiO.sub.3.(Y)Z, wherein 55 wt. %≦W≦97 wt. %, 2.5 wt. %≦X≦45 wt. %, 0.5 wt. %≦Y≦20 wt. %, and Z is at least one material selected from the group consisting of barium titanate and strontium titanate.

Claim 3

The composition of claim 1, wherein Z consists of barium titanate.

Claim 4

The composition of claim 1, wherein Z consists of strontium titanate.

Claim 5

An electrostrictive ceramic composition consisting essentially of a solid solution of lead magnesium niobate, lead titanate and at least one dopant selected from the group consisting of barium titanate and strontium titanate, said composition being defined by the following formula: (W)Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3.(X)PbTiO.sub.3.(Y)Z, wherein 82 wt. %≦W≦94 wt. %, 4 wt. %≦X≦18 wt. %, 0.5 wt. %≦Y≦6 wt. %, and Z is at least one material selected from the group consisting of barium titanate and strontium titanate.

Claim 6

An electrostrictive ceramic composition consisting essentially of a solid solution of lead magnesium niobate, lead titanate and at least one dopant selected from the group consisting of barium titanate and strontium titanate, said composition being defined by the following formula: (W)Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3.(X)PbTiO.sub.3.(Y)Z, wherein 82 wt. %≦W≦94 wt. %, 4 wt. %≦X≦18 wt. %, 0.5 wt. %≦Y≦6 wt. %, and Z is at least one material selected from the group consisting of barium titanate and strontium titanate.

Claim 7

The composition of claim 4, wherein Z consists of barium titanate.

Claim 8

The composition of claim 4, wherein Z consists of strontium titanate.

Claim 9

An electrostrictive ceramic composition consisting essentially of a solid solution of lead magnesium niobate, lead titanate and at least one dopant selected from the group consisting of barium titanate and strontium titanate, said composition being defined by the following formula: (W)Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3.(X)PbTiO.sub.3.(Y)Z, wherein

Claim 10

An electrostrictive ceramic composition consisting essentially of a solid solution of lead magnesium niobate, lead titanate and at least one dopant selected from the group consisting of barium titanate and strontium titanate, said composition being defined by the following formula: (W)Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3.(X)PbTiO.sub.3.(Y)Z, wherein

Claim 11

5 wt. %≦W≦86.2 wt. %, 11.5 wt. %≦X≦11.8 wt. %, 2.0 wt. %≦Y≦4.0 wt. %, and Z is at least one material selected from the group consisting of barium titanate and strontium titanate.

Claim 12

5 wt. %≦W≦86.2 wt. %, 11.5 wt. %≦X≦11.8 wt. %, 2.0 wt. %≦Y≦4.0 wt. %, and Z is at least one material selected from the group consisting of barium titanate and strontium titanate.

Claim 13

The composition of claim 7, wherein Z consists of barium titanate.

Claim 14

The composition of claim 7, wherein Z consists of strontium titanate.

Claim 15

The composition of claim 8, wherein W=86.2 wt. %, X=11.8 wt. %, and Y=2.0 wt. %.

Claim 16

The composition of claim 8, wherein W=84.5 wt. %, X=11.5 wt. %, and Y=4.0 wt. %.

Claim 17

The composition of claim 9, wherein W=86.2 wt. %, X=11.8 wt. %, and Y=2.0 wt. %.

Claim 18

The composition of claim 9, wherein W=84.5 wt. %, X=11.5 wt. %, and Y=4.0 wt. %.

Claim 19

A sintered electrostrictive ceramic composition consisting essentially of a solid solution of about 96 to about 98 weight percent of a mixture of 88 weight percent lead magnesium niobate and 12 weight percent lead titanate, and about 2 to about 4 weight percent of a dopant selected from the group consisting of barium titanate and strontium titanate, said sintered electrostrictive ceramic composition having a crystal phase of approximately 100% perovskite.

Claim 20

A sintered electrostrictive ceramic composition consisting essentially of a solid solution of about 96 to about 98 weight percent of a mixture of 88 weight percent lead magnesium niobate and 12 weight percent lead titanate, and about 2 to about 4 weight percent of a dopant selected from the group consisting of barium titanate and strontium titanate, said sintered electrostrictive ceramic composition having a crystal phase of approximately 100% perovskite.

Claim 21

The composition of claim 14, wherein said composition has a dielectric constant that exhibits a temperature dependency as shown in graphs 2, 3, a and b of FIG. 5.

Claim 22

The composition of claim 14, wherein the dielectric constant of said composition is within -41% to +28% of a 25° C. dielectric constant value of said composition over a temperature range of 0° C. to 50° C.

Claim 23

The composition of claim 14, wherein the dielectric constant of said composition is within -41% to +14% of a 25° C. dielectric constant value of said composition over a temperature range of 0° C. to 50° C.

Claim 24

The composition of claim 14, wherein the dielectric constant of said composition is within -33% to +3% of a 25° C. dielectric constant value of said composition over a temperature range of 0° C. to 50° C.

Claim 25

The composition of claim 14, wherein a dielectric constant of said composition is within -21% to +0.8% of a 25° C. dielectric constant value of said composition over a temperature range of 0° C. to 50° C.

Claim 26

The composition of claim 14, wherein the composition has a maximum dielectric constant of approximately 13,280-17,544.

Claim 27

The composition of claim 14, wherein the sintered composition has a density of approximately 7.27-7.50 g/cc.

Claim 28

The composition of claim 14, wherein the sintered composition has a maximum Curie temperature of approximately 20.6° C.-44.2° C.

Claim 29

A sintered electrostrictive composition consisting essentially of a solid solution of about 98 to about 99.5 weight percent of a mixture of 88 weight percent lead magnesium niobate and 12 weight percent lead titanate, and about 0.5 to about 2 weight percent of a dopant consisting of barium titanate, said sintered electrostrictive ceramic composition having a crystal phase of approximately 100% perovskite.

Claim 30

A sintered electrostrictive composition consisting essentially of a solid solution of about 98 to about 99.5 weight percent of a mixture of 88 weight percent lead magnesium niobate and 12 weight percent lead titanate, and about 0.5 to about 2 weight percent of a dopant consisting of barium titanate, said sintered electrostrictive ceramic composition having a crystal phase of approximately 100% perovskite.

Claim 31

The composition of claim 23, wherein said composition has a dielectric constant that exhibits a temperature dependency as shown in graph A of FIG. 6.

Claim 32

The composition of claim 23, wherein the dielectric constant of said composition is within -34% to +10% of a 25° C. dielectric constant value of said composition over a temperature range of 0° C. to 50° C.

Claim 33

The composition of claim 23, wherein the composition has a maximum dielectric constant of approximately 16,701.

Claim 34

The composition of claim 23, wherein the sintered composition has an average density of approximately 7.66 g/cc.

Claim 35

The composition of claim 23, wherein the sintered composition has a maximum Curie temperature of approximately 42.2° C.

Claim 36

A sintered electrostrictive ceramic composition consisting essentially of a solid solution of about 96 to about 98 weight percent of a mixture of 88 weight percent lead magnesium niobate and 12 weight percent lead titanate, and about 2 to about 4 weight percent of a dopant selected from the group consisting of barium titanate and strontium titanate, said sintered electrostrictive ceramic composition having a maximum dielectric constant of approximately 13280-17544, said composition having been produced by: mixing together powders of Pb(Mg 1/3 Nb 170 )O 3 , PbTiO 3 , PbO, TiO 2 and at least one dopant material selected from the group consisting of SrCO 3 and BaCO 3 in desired stoichiometric proportions to form a mixture; wet milling said mixture; drying and calcining said mixture to form a calcined powder; wet milling said calcined powder; forming a binder-distilled water mixture; adding said calcined powder to said binder-distilled water mixture to form a slurry; evaporating substantially all water from the slurry to form a dried mass; grinding the dried mass to -100 mesh powder; dry pressing said -100 mesh powder to form compacts; isostatically pressing said compacts to form pellets; packing the pellets into a powder having substantially the same chemical composition as the pellets; and firing the pellets.

Claim 37

A sintered electrostrictive ceramic composition consisting essentially of a solid solution of about 96 to about 98 weight percent of a mixture of 88 weight percent lead magnesium niobate and 12 weight percent lead titanate, and about 2 to about 4 weight percent of a dopant selected from the group consisting of barium titanate and strontium titanate, said sintered electrostrictive ceramic composition having a maximum dielectric constant of approximately 13280-17544, said composition having been produced by: mixing together powders of Pb(Mg 1/3 Nb 170 )O 3 , PbTiO 3 , PbO, TiO 2 and at least one dopant material selected from the group consisting of SrCO 3 and BaCO 3 in desired stoichiometric proportions to form a mixture; wet milling said mixture; drying and calcining said mixture to form a calcined powder; wet milling said calcined powder; forming a binder-distilled water mixture; adding said calcined powder to said binder-distilled water mixture to form a slurry; evaporating substantially all water from the slurry to form a dried mass; grinding the dried mass to -100 mesh powder; dry pressing said -100 mesh powder to form compacts; isostatically pressing said compacts to form pellets; packing the pellets into a powder having substantially the same chemical composition as the pellets; and firing the pellets.

Claim 38

The composition of claim 29, wherein the dielectric constant of said composition is within -41% to +28% of a 25° C. dielectric constant value of said composition over a temperature range of 0° C. to 50° C.

Claim 39

The composition of claim 29, wherein the dielectric constant of said composition is within -41% to +14% of a 25° C. dielectric constant value of said composition over a temperature range of 0° C. to 50° C.

Claim 40

The composition of claim 29, wherein the dielectric constant of said composition is within -33% to +3% of a 25° C. dielectric constant value of said composition over a temperature range of 0° C. to 50° C.

Claim 41

The composition of claim 29, wherein the dielectric constant of said composition is within -21% to +0.8% of a 25° C. dielectric constant value of said composition over a temperature range of 0° C. to 50° C.

Claim 42

The sintered electrostrictive ceramic composition of claim 19, wherein the sintered composition has a density of approximately 7.27-7.50 g/cm 3 .

Claim 43

The sintered electrostrictive ceramic composition of claim 29, wherein the sintered composition has a Curie temperature of about 20.6° to about 44.2° C.

Claim 44

A sintered electrostrictive ceramic composition consisting essentially of a solid solution of about 96 to about 98 weight percent of a mixture of 88 weight percent lead magnesium niobate and 12 weight percent lead titanate, and about 2 to about 4 weight percent of a dopant selected from barium titanate and strontium titanate, said composition produced by: mixing together powders of MgO and Nb 2 O 5 in desired stoichiometric proportions to form a mixture; wet milling said mixture; drying and calcining said mixture to form a calcined powder; mixing together said calcined powder, with starting powders of TiO 2 , PbO and at least one dopant material selected from the group consisting of BaCO 3 and SrCO 3 in desired stoichiometric proportions to form a second mixture; wet milling said second mixture; drying and calcining said second mixture to form a second calcined powder; wet milling said second calcined powder; forming a binder-distilled water mixture; adding said second calcined powder to said binder-distilled water mixture to form a slurry; evaporating substantially all water from the slurry to form a dried mass; grinding the dried mass to -100 mesh powder; dry pressing said -100 mesh powder to form compacts; isostatically pressing said compacts to form pellets; packing the pellets into a powder having substantially the same chemical composition as the pellets; and firing the pellets.

Claim 45

A sintered electrostrictive ceramic composition consisting essentially of a solid solution of about 96 to about 98 weight percent of a mixture of 88 weight percent lead magnesium niobate and 12 weight percent lead titanate, and about 2 to about 4 weight percent of a dopant selected from barium titanate and strontium titanate, said composition produced by: mixing together powders of MgO and Nb 2 O 5 in desired stoichiometric proportions to form a mixture; wet milling said mixture; drying and calcining said mixture to form a calcined powder; mixing together said calcined powder, with starting powders of TiO 2 , PbO and at least one dopant material selected from the group consisting of BaCO 3 and SrCO 3 in desired stoichiometric proportions to form a second mixture; wet milling said second mixture; drying and calcining said second mixture to form a second calcined powder; wet milling said second calcined powder; forming a binder-distilled water mixture; adding said second calcined powder to said binder-distilled water mixture to form a slurry; evaporating substantially all water from the slurry to form a dried mass; grinding the dried mass to -100 mesh powder; dry pressing said -100 mesh powder to form compacts; isostatically pressing said compacts to form pellets; packing the pellets into a powder having substantially the same chemical composition as the pellets; and firing the pellets.

Claim 46

An electrostrictive ceramic composition comprising a solid solution of lead magnesium niobate, lead titanate and strontium titanate, said composition being defined by the following formula: (W)Pb(Mg.sub.1/3 Nb.sub.170 )O.sub.3.(X)PbTiO.sub.3.(Y)SrTiO.sub.3, wherein 55 wt. %≦W≦97 wt. %, 2.5 wt. %≦X≦45 wt. %, and 0.5 wt. %≦Y≦20 wt. %.

Claim 47

An electrostrictive ceramic composition comprising a solid solution of lead magnesium niobate, lead titanate and strontium titanate, said composition being defined by the following formula: (W)Pb(Mg.sub.1/3 Nb.sub.170 )O.sub.3.(X)PbTiO.sub.3.(Y)SrTiO.sub.3, wherein 55 wt. %≦W≦97 wt. %, 2.5 wt. %≦X≦45 wt. %, and 0.5 wt. %≦Y≦20 wt. %.

Claim 48

The electrostrictive ceramic composition of claim 37, wherein 82 wt. %≦W≦94 wt. %, 4 wt. %≦X≦18 wt. %, and 0.5 wt. %≦Y≦6 wt. %.

Claim 49

The electrostrictive ceramic composition of claim 37, wherein 84.5 wt. %≦W≦86.2 wt. %, 11.5 wt. %≦X≦11.8 wt. %, and 2.0 wt. %≦Y≦4.0 wt. %.