Method of preparing ferroelectric ceramics

Claim 1

A method of preparing ferroelectric ceramics selected from the group consisting of: I pb ([B 1 ] A Nb 1-A )O 3 -PbTiO 3 -PbZrO 3 , where [B 1 ] is one member selected from the group consisting of Mg, Zn, Cd, Sn, Mn, Fe, Co and Ni when A=1/3, and [B 1 ] is one member selected from the group consisting of Li and Cu when A=1/4, Ii. pb ([B 2 ] B Nb 1-B )O 3 -Pb([B 3 ] C Nb 1-C )O 3 -PbTiO 3 -PbZrO 3 , where each of [B 2 ] and [B 3 ], [B 2 ]≠[B 3 ], is one member selected from the group consisting of Mg, Zn, Cd, Sn, Mn, Fe, Co and Ni when B and C=1/3, and each of [B 2 ] and [B 3 ], [B 2 ]≠[B 3 ], is one member selected from the group consisting of Li and Cu when B and C=1/4, Iii. pb ([B 1 ] A Nb 1-A )O 3 -PbTiO 3 -PbZrO 3 with MnO 2 , where [B 1 ] is one member selected from the group consisting of Mg, Zn, Cd, Sn, Fe, Co and Ni when A=1/3, and [B 1 ] is one member selected from the group consisting of Li and Cu when A=1/4, and Iv. pb([B 2 ] B Nb 1-B )O 3 -Pb([B 3 ] C Nb 1-C )O 3 -PbTiO 3 -PbZrO 3 with MnO 2 , where each of [B 2 ] and [B 3 ], [B 2 ≠B 3 ], is one member selected from the group consisting of Mg, Zn, Cd, Sn, Fe, Co and Ni when B and C=1/3, and each of [B 2 ] and [B 3 ], [B 2 ]≠[B 2 ], is one member selected from the group consisting of Li and Cu when B and C=1/4,

Claim 2

A method of preparing ferroelectric ceramics selected from the group consisting of: I pb ([B 1 ] A Nb 1-A )O 3 -PbTiO 3 -PbZrO 3 , where [B 1 ] is one member selected from the group consisting of Mg, Zn, Cd, Sn, Mn, Fe, Co and Ni when A=1/3, and [B 1 ] is one member selected from the group consisting of Li and Cu when A=1/4, Ii. pb ([B 2 ] B Nb 1-B )O 3 -Pb([B 3 ] C Nb 1-C )O 3 -PbTiO 3 -PbZrO 3 , where each of [B 2 ] and [B 3 ], [B 2 ]≠[B 3 ], is one member selected from the group consisting of Mg, Zn, Cd, Sn, Mn, Fe, Co and Ni when B and C=1/3, and each of [B 2 ] and [B 3 ], [B 2 ]≠[B 3 ], is one member selected from the group consisting of Li and Cu when B and C=1/4, Iii. pb ([B 1 ] A Nb 1-A )O 3 -PbTiO 3 -PbZrO 3 with MnO 2 , where [B 1 ] is one member selected from the group consisting of Mg, Zn, Cd, Sn, Fe, Co and Ni when A=1/3, and [B 1 ] is one member selected from the group consisting of Li and Cu when A=1/4, and Iv. pb([B 2 ] B Nb 1-B )O 3 -Pb([B 3 ] C Nb 1-C )O 3 -PbTiO 3 -PbZrO 3 with MnO 2 , where each of [B 2 ] and [B 3 ], [B 2 ≠B 3 ], is one member selected from the group consisting of Mg, Zn, Cd, Sn, Fe, Co and Ni when B and C=1/3, and each of [B 2 ] and [B 3 ], [B 2 ]≠[B 2 ], is one member selected from the group consisting of Li and Cu when B and C=1/4,

Claim 5

A method of preparing ferroelectric ceramics comprising the material system Pb(Ni 1/3 Nb 2/3 )O 3 -PbTiO 3 -PbZrO 3 in solid solution, said method comprising: calcining at 700° to 900°C a powdered mixture of the oxides, hydroxides or carbonates of the metals to be contained in the ceramics, to form a solid solution and then sintering at 1200° to 1300°C, then heat treating at a temperature lower by about 100° to about 400°C than the sintering temperature, maintaining said heat treatment for from about 1 hour to about 60 hours, and cooling the material subjected to said heat treatment at a cooling rate from about 300° per hour to about 10°C per hour, so as to increase the tensile strength and decrease the resonant impedance of said ceramics.

Claim 6

A method of preparing ferroelectric ceramics comprising the material system Pb(Ni 1/3 Nb 2/3 )O 3 -PbTiO 3 -PbZrO 3 in solid solution, said method comprising: calcining at 700° to 900°C a powdered mixture of the oxides, hydroxides or carbonates of the metals to be contained in the ceramics, to form a solid solution and then sintering at 1200° to 1300°C, then heat treating at a temperature lower by about 100° to about 400°C than the sintering temperature, maintaining said heat treatment for from about 1 hour to about 60 hours, and cooling the material subjected to said heat treatment at a cooling rate from about 300° per hour to about 10°C per hour, so as to increase the tensile strength and decrease the resonant impedance of said ceramics.

Claim 7

A method of preparing ferroelectric ceramics comprising the material system Pb(Mg 1/3 Nb 2/3 )O 3 -Pb(Mn 1/3 Nb 2/3 )O 3 -PbTiO 3 -PbZrO 3 in solid solution, said method comprising: calcining at 700° to 900°C a powdered mixture of the oxides, hydroxides or carbonates of the metals to be contained in the ceramics, to form a solid solution and then sintering at 1200° to 1300°C, then heat treating at a temperature lower by about 100° to about 400°C than the sintering temperature, maintaining said heat treatment for from about 1 hour to about 60 hours, and cooling the material subjected to said heat treatment at a cooling rate from about 300°C per hour to about 10°C per hour so as to increase the tensile strength and decrease the resonant impedance of said ceramics.

Claim 8

A method of preparing ferroelectric ceramics comprising the material system Pb(Mg 1/3 Nb 2/3 )O 3 -Pb(Mn 1/3 Nb 2/3 )O 3 -PbTiO 3 -PbZrO 3 in solid solution, said method comprising: calcining at 700° to 900°C a powdered mixture of the oxides, hydroxides or carbonates of the metals to be contained in the ceramics, to form a solid solution and then sintering at 1200° to 1300°C, then heat treating at a temperature lower by about 100° to about 400°C than the sintering temperature, maintaining said heat treatment for from about 1 hour to about 60 hours, and cooling the material subjected to said heat treatment at a cooling rate from about 300°C per hour to about 10°C per hour so as to increase the tensile strength and decrease the resonant impedance of said ceramics.

Claim 9

A method of preparing ferroelectric ceramics comprising the material system Pb(Li 1/4 Nb 3/4 )O 3 -PbTiO 3 -PbZrO 3 plus MnO 2 in solid solution, said method comprising: calcining at 700° to 900°C a powdered mixture of the oxides, hydroxides or carbonates of the metals to be contained in the ceramics, to form a solid solution and then sintering at 1200° to 1300°C, then heat treating at a temperature lower by about 100° to about 400°C than the sintering temperature, maintaining said heat treatment for from about 1 hour to about 60 hours, and cooling the material subjected to said heat treatment at a cooling rate from about 300° per hour to about 10°C per hour, so as to increase the tensile strength and decrease the resonant impedance of said ceramics.

Claim 10

A method of preparing ferroelectric ceramics comprising the material system Pb(Li 1/4 Nb 3/4 )O 3 -PbTiO 3 -PbZrO 3 plus MnO 2 in solid solution, said method comprising: calcining at 700° to 900°C a powdered mixture of the oxides, hydroxides or carbonates of the metals to be contained in the ceramics, to form a solid solution and then sintering at 1200° to 1300°C, then heat treating at a temperature lower by about 100° to about 400°C than the sintering temperature, maintaining said heat treatment for from about 1 hour to about 60 hours, and cooling the material subjected to said heat treatment at a cooling rate from about 300° per hour to about 10°C per hour, so as to increase the tensile strength and decrease the resonant impedance of said ceramics.

Claim 11

A method of preparing ferroelectric ceramics comprising the material system Pb(Zn 1/3 Nb 2/3 )O 3 -Pb(Sn 1/3 Nb 2/3 )O 3 -PbTiO 3 -PbZrO 3 plus MnO 2 in solid solution, said method comprising: calcining at 700° to 900°C a powdered mixture of the oxides, hydroxides or carbonates of the metals to be contained in the ceramics to form a solid solution and then sintering at 1200° to 1300°C, then heat treating at a temperature lower by about 100°C to about 400°C than the sintering temperature, maintaining said heat treatment for from about 1 hour to about 60 hours, and then cooling said material subjected to said heat treatment at a cooling rate from about 300°C per hour to about 10°C per hour, so as to increase the tensile strength and decrease the resonant impedance of said ceramics.

Claim 12

A method of preparing ferroelectric ceramics comprising the material system Pb(Zn 1/3 Nb 2/3 )O 3 -Pb(Sn 1/3 Nb 2/3 )O 3 -PbTiO 3 -PbZrO 3 plus MnO 2 in solid solution, said method comprising: calcining at 700° to 900°C a powdered mixture of the oxides, hydroxides or carbonates of the metals to be contained in the ceramics to form a solid solution and then sintering at 1200° to 1300°C, then heat treating at a temperature lower by about 100°C to about 400°C than the sintering temperature, maintaining said heat treatment for from about 1 hour to about 60 hours, and then cooling said material subjected to said heat treatment at a cooling rate from about 300°C per hour to about 10°C per hour, so as to increase the tensile strength and decrease the resonant impedance of said ceramics.

Claim 13

A method of preparing ferroelectric ceramics comprising one material selected from the group consisting of Pb(Ni 1/3 Nb 2/3 ) 0 .37 Ti 0 .36 Zr 0 .27 O 3 , Pb(Mg 1/3 Nb 2/3 ) O .06 (Mn 1/3 Nb 2/3 ) 0 .06 Ti 0 .44 Zr 0 .44 O 3 , Pb(Li 1/4 Nb 3/4 ) 0 .1 Ti 0 .43 Zr 0 .47 O 3 +0.8 wt% MnO 2 , and Pb(Zn 1/3 Nb 2/3 ) 0 .05 (Sn 1/3 Nb 2/3 ) 0 .05 Ti 0 .44 Zr 0 .46 O 3 +1 wt% MnO 2 , said method comprising: calcining at 700° to 900°C a powder mixture of the oxides, hydroxides or carbonates of the metals to be contained in the ceramics to form a solid solution and then sintering at 1200° to 1300°C, then heat treating at a temperature lower by about 100° to about 400°C than the sintering temperature of said ceramics, maintaining said heat treatment for from about 1 hour to about 60 hours, and then cooling said material subjected to said heat treatment at a cooling rate from about 300°C per hour to about 10°C per hour, so as to increase the tensile strength and decrease the resonant impedance of said ceramics.

Claim 14

A method of preparing ferroelectric ceramics comprising one material selected from the group consisting of Pb(Ni 1/3 Nb 2/3 ) 0 .37 Ti 0 .36 Zr 0 .27 O 3 , Pb(Mg 1/3 Nb 2/3 ) O .06 (Mn 1/3 Nb 2/3 ) 0 .06 Ti 0 .44 Zr 0 .44 O 3 , Pb(Li 1/4 Nb 3/4 ) 0 .1 Ti 0 .43 Zr 0 .47 O 3 +0.8 wt% MnO 2 , and Pb(Zn 1/3 Nb 2/3 ) 0 .05 (Sn 1/3 Nb 2/3 ) 0 .05 Ti 0 .44 Zr 0 .46 O 3 +1 wt% MnO 2 , said method comprising: calcining at 700° to 900°C a powder mixture of the oxides, hydroxides or carbonates of the metals to be contained in the ceramics to form a solid solution and then sintering at 1200° to 1300°C, then heat treating at a temperature lower by about 100° to about 400°C than the sintering temperature of said ceramics, maintaining said heat treatment for from about 1 hour to about 60 hours, and then cooling said material subjected to said heat treatment at a cooling rate from about 300°C per hour to about 10°C per hour, so as to increase the tensile strength and decrease the resonant impedance of said ceramics.