Piezoelectric composite material

Claim 2

A ferroelectric, pyroelectric or piezoelectric composite material comprising a mixture of one or more polymers and a ferroelectric ceramic powder which contains 90% or more grains in a particle size range of about 1 μm to about 3 mm at a ceramic powder: polymer(s) mixing ratio of about 1:9 to 9:1 by volume, said ferroelectric ceramic powder comprising microcrystals having virtually single domains and being prepared by mixing starting powders in amounts corresponding to the desired chemical composition of the ferroelectric ceramic powder, subjecting the mixed powders to a solid phase reaction, mechanically grinding the reaction product into powder, whereby multiple domains or distorted phases are formed, and then heat annealing the ground powder at a temperature sufficient to reform the multiple domains or distorted phases to virtually single domains.

Claim 3

The composite material of claim 1, wherein said heat annealing is carried out at about 600° to 1200° C. in air or in an atmosphere having an O 2 concentration of about 21% to 100% for about 1 to 30 hours.

Claim 4

The composite material of claim 1, wherein said polymer is a natural rubber or a synthetic rubber or a thermoplastic resin.

Claim 5

The composite material of claim 1, wherein said heat-annealing treatment is carried out 2 to 4 times.

Claim 6

The composite material of claim 1, wherein said ferroelectric ceramic powder contains as a basic composition the following one-, two or three-component systems: I. Perovskite structures selected from (1) to (5); (1) barium titanate and solid solutions containing as the main component barium titanate; (2) lead titanate and solid solutions containing as the main component lead titanate; (3) lead titanate zirconate and solid solutions containing this salt as the main component; (4) three-component ceramics consisting of solid solutions containing lead titanate zirconate and as a third component a salt of lead oxide and other metal oxides belonging to one of the following groups (a) to (f): (a) oxides represented by the formula: A.sup.2+ (B.sub.1/3.sup.2+.B.sub.2/3.sup.5+)O.sub.3 where A 2+ is Pb, Sr or Ba; B 2+ is Zn, Cd, Mg, Ni or Co and B 5+ is Nb or Ta; (b) oxides represented by the formula: A.sup.2+ (B.sub.1/2.sup.2+.B.sub.1/2.sup.6+)O.sub.3 where A 2+ is Pb; B 2+ is Cd, Mn, Zn, Mg, Co or Ni and B 6+ is W or Te; (c) oxides represented by the formula: A.sup.2+ (B.sub.1/2.sup.3+.B.sub.1/2.sup.5+)O.sub.3 where A 2+ is Pb, Ba or Ca; B 3+ is Fe, Sc, Cr, Yb, Lu or In and B 5+ is Nb or Ta; (d) oxides represented by the formula: A.sup.2+ (B.sub.2/3.sup.3+.B.sub.1/3.sup.6+)O.sub.3 wherein A 2+ is Pb; B 3+ is Fe and B 6+ is W; (e) oxides represented by the formula: A.sup.3+ (B.sub.1/2.sup.2+.B.sub.1/2.sup.4+)O.sub.3 wherein A 3+ is La or Nd; B 2+ is Mg and B 4+ is Ti; (f) oxides represented by the formula: (A.sub.1/2.sup.1+.A.sub.1/2.sup.3+)BO.sub.3 wherein A 1+ is Na or K; A 3+ is La, Ce, Nd or Bi and B is Ti; and (5) solid solutions containing NaNbO 3 ; II. tungsten bronze structures; III. bismuth layer structures; IV. LiNbO 3 or LiTaO 3 ; ceramics which containing as a basic composition the above one-, two- or three-component systems, wherein a part of the Pb is replaced by an alkaline earth metal(s); ceramics which contain as a basic composition the above one-, two- or three-component systems and further contain, as a supplemental component, one or more oxides selected from the following groups I, II or III for the purpose of modification: I. Nb 2 O 5 , Ta 2 O 5 , La 2 O 3 , Sb 2 O 5 , Sb 2 O 3 , Bi 2 O 3 and WO 3 ; II. MgO, Fe 2 O 3 , Sc 2 O 3 and K 2 O; and III. Cr 2 O 3 , U 2 O 3 and MnO 2 ; and ceramics which contain as a basic composition the above-described one-, two- or three-component systems, wherein the Pb component is present in excess of the stoichiometric amount.

Claim 7

A ferroelectric, pyroelectric or piezoelectric composite material comprising a mixture of one or more polymers and a ferroelectric ceramic powder which contains 90% or more grains in a particle size range of about 1 μm to about 3 mm at a ceramic powder: polymer(s) mixing ratio of about 1:9 to 9:1 by volume, said ferroelectric ceramic powder comprising microcrystals having virtually single domains and being prepared by mixing starting powders in amounts corresponding to the desired chemical composition of the ferroelectric ceramic powder, subjecting the mixed starting powders to a solid phase reaction, mechanically grinding the reaction product into powder, whereby multiple domains or distorted phases are formed, then heat annealing the ground powder at a temperature sufficient to reform the multiple domains or distorted phases to virtually single domains, and further subjecting the annealed powder to chemical etching in an etching solution under mild conditions such that the distorted phases and amorphous phases present are removed.

Claim 8

A ferroelectric, pyroelectric or piezoelectric composite material comprising a mixture of one or more polymers and a ferroelectric ceramic powder which contains 90% or more grains in a particle size range of about 1 μm to about 3 mm at a ceramic powder: polymer(s) mixing ratio of about 1:9 to 9:1 by volume, said ferroelectric ceramic powder comprising microcrystals having virtually single domains and being prepared by mixing starting powders in amounts corresponding to the desired chemical composition of the ferroelectric ceramic powder, subjecting the mixed starting powders to a solid phase reaction, mechanically grinding the reaction product into powder, whereby multiple domains or distorted phases are formed, then heat annealing the ground powder at a temperature sufficient to reform the multiple domains or distorted phases to virtually single domains, and further subjecting the annealed powder to chemical etching in an etching solution under mild conditions such that the distorted phases and amorphous phases present are removed.

Claim 9

The composite material of claim 6, wherein said chemical etching treatment is accompanied by stirring or light grinding.

Claim 10

The composite material of claim 6, wherein said heat annealing is carried out at about 600° to 1200° C. in air or in an atmosphere having an O 2 concentration of about 21% to 100% for about 1 to 30 hours.

Claim 11

The composite material of claim 6, wherein said polymer is a natural rubber or a synthetic rubber or a thermoplastic resin.

Claim 12

The composite material of claim 6, wherein said heat-annealing treatment is carried out 2 to 4 times.

Claim 13

The composite material of claim 6, wherein etching is carried out using an acid or alkali solution having a pH of about 3 or less or about 13 or more, respectively, or using hydrogen peroxide.

Claim 14

The composite material of claim 6, wherein said ferroelectric ceramic powder contains as a basic composition the following one-, two or three-component systems: I. Perovskite structures selected from (1) to (5): (1) barium titanate and solid solutions containing as the main component barium titanate; (2) lead titanate and solid solutions containing as the main component lead titanate; (3) lead titanate zirconate and solid solutions containing this salt as the main component; (4) three-component ceramics consisting of solid solutions containing lead titanate zirconate and as a third component a salt of lead oxide and other metal oxides belonging to one of the following groups (a) to (f): (a) oxides represented by the formula: A.sup.2+ (B.sub.1/3.sup.2+.B.sub.2/3.sup.5+)O.sub.3 where A 2+ is Pb, Sr or Ba; B 2+ is Zn, Cd, Mg, Ni or Co and B 5+ is Nb or Ta; (b) oxides represented by the formula: A.sup.2+ (B.sub.1/2.sup.2+.B.sub.1/2.sup.6+)O.sub.3 where A 2+ is Pb; B 2+ is Cd, Mn, Zn, Mg, Co or Ni and B 6+ is W or Te; (c) oxides represented by the formula: A.sup.2+ (B.sub.1/2.sup.3+.B.sub.1/2.sup.5+)O.sub.3 where A 2+ is Pb, Ba or Ca; B 3+ is Fe, Sc, Cr, Yb, Lu or In and B 5+ is Nb or Ta; (d) oxides represented by the formula: A.sup.2+ (B.sub.2/3.sup.3+.B.sub.1/3.sup.6+)O.sub.3 wherein A 2+ is Pb; B 3+ is Fe and B 6+ is W; (e) oxides represented by the formula: A.sup.3+ (B.sub.1/2.sup.2+.B.sub.1/2.sup.4+)O.sub.3 wherein A 3+ is La or Nd; B 2+ is Mg and B 4+ is Ti; (f) oxides represented by the formula: (A.sub.1/2.sup.1+.A.sub.1/2.sup.3+)BO.sub.3 wherein A 1+ is Na or K; A 3+ is La, Ce, Nd or Bi and B is Ti; and (5) solid solutions containing NaNbO 3 ; II. tungsten bronze structures; III. bismuth layer structures; IV. LiNbO 3 or LiTaO 3 ; cermaics which containing as a basic composition the above one-, two- or three-component systems, wherein a part of the Pb is replaced by an alkaline earth metal(s); ceramics which contain as a basic composition the above one-, two- or three-component systems and further contain, as a supplemental component, one or more oxides selected from the following groups I, II or III for the purpose of modification: I. Nb 2 O 5 , Ta 2 O 5 , La 2 O 3 , Sb 2 O 5 , Sb 2 O 3 , Bi 2 O 3 and WO 3 ; II. MgO, Fe 2 O 3 , Sc 2 O 3 and K 2 O; and III. Cr 2 O 3 , U 2 O 3 and MnO 2 ; and ceramics which contain as a basic composition the above-described one-, two- or three-component systems, wherein the Pb component is present in excess of the stoichiometric amount.

Claim 15

A ferroelectric, pyroelectric or piezoelectric composite material comprising a mixture of one or more polymers and ferroelectric single crystal powder which contains 90% or more grains in a particle size range of about 1 μm to about 3 mm at a single crystal powder: polymer(s) mixing ratio of about 1:9 to 9:1 by volume, said ferroelectric single crystal powder comprising microcrystals having virtually single domains and being prepared by grinding a single crystal until the resulting powder has the desired particle size, whereby multiple domains or distorted phases are formed, and heat annealing the thus ground powder at a temperature sufficient to reform the multiple doamins or distorted phases to virtually single domains.

Claim 16

A ferroelectric, pyroelectric or piezoelectric composite material comprising a mixture of one or more polymers and ferroelectric single crystal powder which contains 90% or more grains in a particle size range of about 1 μm to about 3 mm at a single crystal powder: polymer(s) mixing ratio of about 1:9 to 9:1 by volume, said ferroelectric single crystal powder comprising microcrystals having virtually single domains and being prepared by grinding a single crystal until the resulting powder has the desired particle size, whereby multiple domains or distorted phases are formed, and heat annealing the thus ground powder at a temperature sufficient to reform the multiple doamins or distorted phases to virtually single domains.

Claim 17

The composite material of claim 13, wherein said heat annealing is carried out at about 600° to 1200° C. in air or in an atmosphere having an O 2 concentration of about 21% to 100% for about 1 to 30 hours.

Claim 18

The composite material of claim 13, wherein said polymer is a natural rubber or a synthetic rubber or a thermoplastic resin.

Claim 19

The composite material of claim 13, wherein said heat-annealing treatment is carried out 2 to 4 times.

Claim 20

A ferroelectric, pyroelectric or piezoelectric composite material comprising a mixture of one or more polymers and a ferroelectric single crystal powder which contains 90% or more grains in a particle size range of about 1 μm to about 3 mm at a single crystal powder: polymer(s) mixing ratio of about 1:9 to 9:1 by volume, said ferroelectric single crystal powder comprising microcrystals having virtually single domains and being prepared by grinding a single crystal until the resulting powder has the desired particle size, whereby multiple domains or distorted phases are formed, heat annealing the thus ground powder at a temperature sufficient to reform the multiple domains or distorted phases to virtually single domains and further subjecting the annealed powder to chemical etching in an etching solution under mild conditions such that the distorted phases and amorphous phases present are removed.

Claim 21

A ferroelectric, pyroelectric or piezoelectric composite material comprising a mixture of one or more polymers and a ferroelectric single crystal powder which contains 90% or more grains in a particle size range of about 1 μm to about 3 mm at a single crystal powder: polymer(s) mixing ratio of about 1:9 to 9:1 by volume, said ferroelectric single crystal powder comprising microcrystals having virtually single domains and being prepared by grinding a single crystal until the resulting powder has the desired particle size, whereby multiple domains or distorted phases are formed, heat annealing the thus ground powder at a temperature sufficient to reform the multiple domains or distorted phases to virtually single domains and further subjecting the annealed powder to chemical etching in an etching solution under mild conditions such that the distorted phases and amorphous phases present are removed.

Claim 22

The composite material of claim 17, wherein said chemical etching treatment is accompanied by stirring or light grinding.

Claim 23

The composite material of claim 17, wherein said heat annealing is carried out at about 600° to 1200° C. in air or in an atmosphere having an O 2 concentration of about 21% to 100% for about 1 to 30 hours.

Claim 24

The composite material of claim 17, wherein said polymer is a natural rubber or a synthetic rubber or a thermoplastic resin.

Claim 25

The composite material of claim 17, wherein said heat-annealing treatment is carried out 2 to 4 times.

Claim 26

The composite material of claim 17, wherein etching is carried out using an acid or alkali solution having a pH of about 3 or less or about 13 or more, respectively, or using hydrogen peroxide.