JP2006248829A - Piezoelectric porcelain composition, its manufacturing method and piezoelectric element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable the use of an inexpensive metal material such as Cu and Ni as an electrode material, and to inhibit decreases in electric resistance at an elevated temperature and electromechanical coupling coefficient kr. <P>SOLUTION: The piezoelectric porcelain composition essentially comprises a complex oxide comprising Pb, Ti and Zr as constituent elements and contains at least one chosen from Mn, Co, Cr, Fe and Ni as a first subsidiary component, wherein the amount of the first subsidiary component is ≤0.2 mass% (but not 0) calculated in terms of oxides. The piezoelectric porcelain composition is fired under a reductive firing condition, e.g. at a firing temperature of 800-1,000°C and an oxygen partial pressure of from 1×10<SP>-10</SP>to 1×10<SP>-6</SP>atm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a piezoelectric ceramic composition suitable for piezoelectric layers of various piezoelectric elements such as actuators, piezoelectric buzzers, sounding bodies, sensors, and the like, and further relates to a manufacturing method thereof and a piezoelectric element using the same.

  For example, an actuator that uses displacement generated by the piezoelectric effect as a mechanical drive source has advantages such as low power consumption and heat generation, good response, and miniaturization and weight reduction. However, it has come to be used in a wide range of fields.

A piezoelectric ceramic composition used for this type of actuator is required to have a large piezoelectric characteristic, particularly a piezoelectric strain constant. As a piezoelectric ceramic composition satisfying this, for example, lead titanate (PbTiO ₃ ) and lead zirconate ( PbZrO ₃ ) and zinc / lead niobate [Pb (Zn _1/3 Nb _2/3 ) O ₃ ] are used in the ternary piezoelectric ceramic composition or the ternary piezoelectric ceramic composition. Piezoelectric ceramic compositions and the like in which a part of these are replaced with Sr, Ba, Ca, and the like have been developed.

  However, these conventional piezoelectric ceramic compositions need to be fired at a relatively high temperature, and since firing is performed in an oxidizing atmosphere, for example, in a laminated actuator that simultaneously fires internal electrodes, a high melting point is obtained. It is necessary to use a noble metal (for example, Pt, Pd, etc.) that does not oxidize even when fired in an oxidizing atmosphere. As a result, the cost is increased and the cost of the manufactured piezoelectric element is hindered.

  From such a situation, the applicant of the present application includes, in the ternary piezoelectric ceramic composition, a first subcomponent including at least one selected from Fe, Co, Ni, and Cu, and Sb, Nb, and Ta. It has been proposed that low temperature firing is possible by adding a second subcomponent including at least one selected, and that an inexpensive material such as an Ag—Pd alloy can be used for the internal electrode (see Patent Document 1). ).

The invention described in Patent Document 1 includes the ternary piezoelectric ceramic composition and the piezoelectric ceramic composition in which part of Pb is replaced with Sr, Ba, Ca, etc. in the ternary piezoelectric ceramic composition. By adding a first subcomponent including at least one selected from Co, Ni, and Cu and a second subcomponent including at least one selected from Sb, Nb, and Ta, a high piezoelectric strain constant is obtained. Provided is a piezoelectric ceramic composition that is densified without impairing various piezoelectric characteristics even when fired at a low temperature and has increased mechanical strength, and has a piezoelectric layer composed of the piezoelectric ceramic composition. That's it.
JP 2004-137106 A

  By the way, when a cheaper metal (for example, Cu or Ni) is used as an electrode material, the firing in an oxidizing atmosphere (for example, in the air) oxidizes the electrode material even if it is fired at a low temperature, and the conductivity is impaired. Inconvenience occurs.

In order to eliminate the inconvenience as described above, it is necessary to perform firing in a reducing atmosphere having a low oxygen partial pressure (the oxygen partial pressure is about 1 × 10 ⁻⁹ to 1 × 10 ⁻⁶ atm). However, when fired in a reducing atmosphere, the obtained fired body contains more oxygen vacancies than a sintered body fired in air, and therefore has an insulation resistance particularly at high temperatures (100 ° C. or higher). This leads to a decrease in the insulation life of the product. The temperature range of 100 ° C. to 200 ° C. is often the standard operating temperature of a product, and a decrease in insulation resistance and insulation life in this temperature range is a serious problem that significantly impairs the reliability of the product.

  From this point of view, in the technique described in Patent Document 1, the value of the electrical resistance at a high temperature itself is improved by the addition of the first subcomponent and the second subcomponent. The drop compared with the electrical resistance at normal temperature is hardly improved, and further improvement is required for the electrical resistance at high temperature.

  The present invention has been proposed in view of such a conventional situation, and an inexpensive metal material such as Cu or Ni can be used as an electrode material, and electric resistance is improved while maintaining high piezoelectric characteristics. An object of the present invention is to provide a piezoelectric ceramic composition that can be used and a method for producing the same. Another object of the present invention is to provide a piezoelectric element that is inexpensive and excellent in reliability by using the piezoelectric ceramic composition.

  In order to achieve the above object, the present inventors have made various studies over a long period of time. As a result, by adding a small amount of any of Mn, Co, Cr, Fe, and Ni, it is possible to obtain a conclusion that the electrical resistance can be improved specifically and the decrease in the electromechanical coupling coefficient kr can be suppressed. It came.

  The present invention has been devised based on the above examination results, and is a piezoelectric ceramic composition mainly composed of a composite oxide containing Pb, Ti, and Zr as constituent elements, and as a first subcomponent It contains at least one selected from Mn, Co, Cr, Fe, and Ni, and the content of the first subcomponent is 0.2% by mass or less in terms of oxide (however, 0 is not included). It is characterized by.

  By adding a small amount of a component containing at least one selected from Mn, Co, Cr, Fe, and Ni as a subcomponent, a decrease in electrical resistance at high temperatures can be suppressed while maintaining high piezoelectric characteristics. Although the detailed mechanism is unknown for the reason, it is true that the insulation life is remarkably improved by adding a small amount of these components, for example, satisfying the reliability standard required for automobile parts. Improved to level. Further, the decrease of the electromechanical coupling coefficient kr at this time is a level that hardly causes a problem.

  However, if the amount of the first subcomponent added is too large, the piezoelectric characteristics (for example, the electromechanical coupling coefficient kr) are lowered, and the improvement in the electrical resistance is also lowered. Therefore, in this invention, the addition amount of the said 1st subcomponent shall be 0.2 mass% or less.

  The addition of Fe, Co, and Ni is also described in the above-mentioned Patent Document 1. However, in Patent Document 1, the amount added is larger than that specified in the present invention, and firing under reducing firing conditions is not considered. As in the present invention, the addition of a small amount is effective in suppressing the decrease from the electrical resistance at normal temperature, and further, it has not been recognized at all about improving the insulation resistance in firing in a reducing atmosphere. .

  According to the present invention, an inexpensive metal material such as Cu or Ni can be used as the electrode material of the internal electrode, the electrical resistance is improved, and the piezoelectric ceramic composition does not decrease the piezoelectric characteristics, for example, the electromechanical coupling coefficient kr. Can be provided. Therefore, according to the present invention, it is possible to provide a piezoelectric element that is inexpensive and has excellent insulation life and high reliability.

  Hereinafter, a piezoelectric ceramic composition to which the present invention is applied, a manufacturing method thereof, and a piezoelectric element using the piezoelectric ceramic composition will be described in detail.

The piezoelectric ceramic composition of the present invention is mainly composed of a composite oxide containing Pb, Ti, and Zr as constituent elements. Here, the composite oxide is composed of, for example, lead titanate (PbTiO ₃ ), lead zirconate (PbZrO ₃ ), and zinc / lead niobate [Pb (Zn _1/3 Nb _2/3 ) O ₃ ]. Or a composite oxide obtained by substituting a part of Pb with Sr, Ba, Ca, or the like in the ternary composite oxide.

  Specific examples of the composition include composite oxides represented by the following formula (1) or (2). In these formulas (1) and (2), the oxygen composition is obtained stoichiometrically, and deviation from the stoichiometric composition is allowed in the actual composition. .

Pb _a [(Zn _1/3 Nb _2/3 ) _x Ti _y Zr _z ] O ₃ (1)
(However, 0.96 ≦ a ≦ 1.03, 0.05 ≦ x ≦ 0.15, 0.25 ≦ y ≦ 0.5, 0.35 ≦ z ≦ 0.6, and x + y + z = 1.)

(Pb _a-b Me _b ) [(Zn _1/3 Nb _2/3 ) _x Ti _y Zr _z ] O ₃ (2)
(However, 0.96 ≦ a ≦ 1.03, 0 <b ≦ 0.1, 0.05 ≦ x ≦ 0.15, 0.25 ≦ y ≦ 0.5, 0.35 ≦ z ≦ 0.6 X + y + z = 1, and Me in the formula represents at least one selected from Sr, Ca, and Ba.)

  The composite oxide has a so-called perovskite structure, and Pb and the substitution element Me in the formula (2) are located at a so-called A site of the perovskite structure. Zn, Nb, Ti, and Zr are located at the so-called B site of the perovskite structure.

  In the composite oxide represented by the formula (1) or formula (2), the ratio a of the A site element is preferably 0.96 ≦ a ≦ 1.03. If the A-site element ratio a is less than 0.96, firing at low temperatures may be difficult. On the contrary, when the ratio a of the A site element exceeds 1.03, the density of the obtained piezoelectric ceramic is lowered, and as a result, sufficient piezoelectric characteristics may not be obtained, and the mechanical strength may also be lowered. is there.

  In the composite oxide represented by the above formula (2), a part of Pb is substituted with the substitution element Me (Sr, Ca, Ba), but this can increase the piezoelectric strain constant. However, if the substitution amount b of the substitution element Me is too large, the sinterability is lowered, and as a result, the piezoelectric strain constant is reduced and the mechanical strength is also lowered. Also, the Curie temperature tends to decrease as the substitution amount b increases. Therefore, the substitution amount b of the substitution element Me is preferably 0.1 or less.

  On the other hand, among the B site elements, the ratio x between Zn and Nb is preferably 0.05 ≦ x ≦ 0.15. The ratio x affects the firing temperature. If this value is less than 0.05, the effect of lowering the firing temperature may be insufficient. On the other hand, if it exceeds 0.15, the sinterability is affected, and as a result, the piezoelectric strain constant may be reduced and the mechanical strength may be reduced.

  Of the B-site elements, the Ti ratio y and the Zr ratio z are preferably set in terms of piezoelectric characteristics. Specifically, the Ti ratio y is preferably 0.25 ≦ y ≦ 0.5, and the Zr ratio z is preferably 0.35 ≦ z ≦ 0.6. By setting it within the above range, a large piezoelectric strain constant can be obtained in the vicinity of the morphotropic phase boundary (MPB).

  The piezoelectric ceramic composition of the present invention is characterized in that it contains the composite oxide as a main component and a component containing at least one selected from Mn, Co, Cr, Fe, and Ni as a first subcomponent. Is a point. By containing the first subcomponent, a decrease in electrical resistance at a high temperature is remarkably suppressed.

  However, if the content of the first subcomponent becomes too large, the piezoelectric characteristics, for example, the electromechanical coupling coefficient kr may be lowered. Therefore, the content is 0.2% by mass or less (however, 0 is not included). ) Is preferable. If the content of the first subcomponent exceeds 0.2% by mass, the electromechanical coupling coefficient kr may be 50 or less. More preferably, it is 0.01-0.2 mass%. In addition, content of the said 1st subcomponent is a value when converted into an oxide. For example, in the case of Mn, the value converted to MnO, in the case of Co, the value converted to CoO, in the case of Cr, the value converted to CrO, in the case of Fe, the value converted to FeO, in the case of Ni Is a value converted to NiO.

The piezoelectric ceramic composition of the present invention may contain a second subcomponent in addition to the first subcomponent. In this case, the second subcomponent is at least one selected from Ta, Sb, Nb, and W. By adding the second subcomponent, piezoelectric characteristics and mechanical strength can be improved. However, the content of these second subcomponents is preferably 1.0% by mass or less in terms of oxide. For example, in the case of Ta, 1.0% by mass or less in terms of Ta ₂ O ₅ , in the case of Sb, 1.0% by mass or less in terms of Sb ₂ O ₃ , and in the case of Nb, 1.0% by mass in terms of Nb ₂ O ₅ Hereinafter, in the case of W, it is 1.0 mass% or less in terms of WO ₃ . When the content of the second subcomponent exceeds 1.0% by mass in terms of the oxide, the sinterability may be reduced and the piezoelectric characteristics may be deteriorated.

The above is the configuration relating to the composition of the piezoelectric ceramic composition of the present invention. One of the major features is that the piezoelectric ceramic composition of the present invention is fired under reducing firing conditions. As described above, when firing in an oxidizing atmosphere, for example, a noble metal needs to be used as an electrode material of an internal electrode of a piezoelectric element. On the other hand, since the piezoelectric ceramic composition of the present invention is fired under reducing firing conditions, an inexpensive electrode material such as Cu or Ni can be used for the internal electrode. Here, the reducing firing conditions are, for example, a firing temperature of 800 ° C. to 1200 ° C. and an oxygen partial pressure of 1 × 10 ⁻¹⁰ to 1 × 10 ⁻⁶ atm.

  When firing under the reducing firing conditions, a decrease in electrical resistance at high temperatures becomes a problem. However, since the piezoelectric ceramic composition of the present invention contains the first subcomponent as described above, Can be avoided. In addition, since the piezoelectric ceramic composition of the present invention is fired under reducing firing conditions, an inexpensive electrode material such as Cu or Ni can be used for the internal electrode, and as described above, While eliminating the decrease in resistance, it is possible to avoid a decrease in piezoelectric characteristics.

  Next, the manufacturing method of the piezoelectric ceramic composition of this invention is demonstrated. The piezoelectric ceramic composition of the present invention is produced by firing under reducing firing conditions. The production method is as follows.

First, for example, PbO powder, ZnO powder, Nb ₂ O ₅ powder, TiO ₂ powder, and ZrO ₂ powder are prepared as the main component raw materials. When the main component is a complex oxide represented by the formula (2), at least one of SrCO ₃ powder, BaCO ₃ powder, and CaCO ₃ powder is further prepared.

In addition, as the first subcomponent material (additional species), at least one of oxides and carbonates of each element, such as MnCO ₃ , CoO, Cr ₂ O ₃ , Fe ₂ O ₃ , and NiO, is prepared. When the second subcomponent is added, necessary ones are prepared from Ta ₂ O ₅ powder, Sb ₂ O ₃ powder, Nb ₂ O ₅ powder, and WO ₃ powder.

  The raw materials for the main component, the first subcomponent, and the second subcomponent are not limited to the exemplified oxide powder or carbonate powder, but may be any oxide that can be fired. Anything may be used. For example, carbonate powder, oxalate powder, hydroxide powder, or the like can be used instead of the exemplified oxide powder. Similarly, oxide powder, oxalate powder, hydroxide powder, or the like can be used instead of the exemplified carbonate powder.

  Next, after sufficiently drying these raw materials, the respective raw materials are weighed according to a desired final composition, and are sufficiently mixed in an organic solvent or in water using, for example, a ball mill or the like. After drying this, for example, it is calcined at about 700 to 950 ° C. for 1 to 4 hours. Subsequently, the calcined product is sufficiently pulverized in an organic solvent or water using a ball mill or the like, dried, and then granulated by adding a binder such as polyvinyl alcohol or an acrylic resin, and then uniaxial press molding machine or static Press molding using a hydraulic molding machine (CIP) or the like.

After the molding, the molded body is fired. In the present invention, the molded body is fired under reducing firing conditions. Specifically, firing is performed at a firing temperature of 800 ° C. to 1200 ° C. in a reducing atmosphere (for example, oxygen partial pressure of 1 × 10 ⁻¹⁰ to 1 × 10 ⁻⁶ atm). Since the piezoelectric ceramic composition of the present invention is fired at a relatively low temperature under reducing firing conditions as described above, for example, there is no restriction on the electrode material used for the internal electrode, and an inexpensive electrode material such as Cu or Ni is used. Can be used. In addition, deterioration of electrical resistance or the like due to firing under reducing firing conditions is eliminated by adding the first subcomponent, and there is no problem in terms of characteristics.

  After firing, the obtained sintered body is polished as necessary, and polarization treatment is performed by applying an electric field in a heated silicone oil or the like with a polarization electrode connected thereto. Ceramic).

  In the above-described manufacturing method, the raw materials of the first subcomponent and the second subcomponent may be mixed with the main component raw material before calcination, for example, in the first raw material mixing process, You may make it mix with what grind | pulverized the calcined material.

  The piezoelectric ceramic composition described above can be used as piezoelectric materials for various piezoelectric elements such as actuators, piezoelectric transformers, ultrasonic motors, piezoelectric buzzers, sounding bodies, sensors, and the like. Next, a configuration example of the piezoelectric element will be described by taking a multilayer actuator as an example.

  FIG. 1 shows an example of a laminated actuator. As shown in FIG. 1, the multilayer actuator 1 includes a multilayer body 4 in which internal electrodes 3 are inserted between a plurality of piezoelectric layers 2, and the multilayer body 4 contributes to displacement as an active portion. Although the thickness per layer of the piezoelectric layer 2 can be set arbitrarily, it is usually set to about 1 μm to 100 μm, for example. On both sides of the laminate 4, there are piezoelectric layer regions where the internal electrodes 3 are not formed as inactive regions. The thickness of the piezoelectric layer in this portion is thicker than the thickness of the piezoelectric layer 2 between the internal electrodes 3. It may be set.

  In the piezoelectric element of the present invention, the piezoelectric ceramic composition described above is used for the piezoelectric layer 2. On the other hand, the internal electrode 3 has a function as an electrode for applying a voltage to each piezoelectric layer 2 and, of course, is made of a conductive material. In this case, noble metals such as Ag, Au, Pt, and Pd can be used as the conductive material. However, since the piezoelectric ceramic composition of the present invention described above is used for the piezoelectric layer 2, Cu, Ni, etc. An inexpensive electrode material can be used. As described above, the piezoelectric ceramic composition of the present invention is fired at a low temperature under reducing firing conditions, and can be used as the internal electrode 3 even if it is easily oxidized and has a low melting point such as Cu or Ni. . If these inexpensive electrode materials are used, the manufacturing cost of the multilayer actuator 1 can be reduced.

  The internal electrodes 3 are alternately extended in opposite directions, for example, and terminal electrodes 5 and 6 electrically connected to the internal electrodes 3 are provided at the ends in the extending directions. The terminal electrodes 5 and 6 may be formed, for example, by sputtering a metal such as Au, or may be formed by baking an electrode paste. The thicknesses of the terminal electrodes 5 and 6 are appropriately set depending on the application, the size of the multilayer actuator 1, and the like, but are usually about 10 μm to 50 μm.

  The laminated actuator 1 is manufactured as follows. First, as described in the production of the piezoelectric ceramic composition, a vehicle is added to a powder obtained by pulverizing the calcined product (including the first subcomponent) and kneaded to prepare a piezoelectric layer paste. At the same time, the conductive material is kneaded with the vehicle to produce an internal electrode paste. Note that additives such as a dispersant, a plasticizer, a dielectric material, and an insulating material may be added to the internal electrode paste as necessary.

  Subsequently, by using the piezoelectric layer paste and the internal electrode paste, a green chip that is a precursor of the multilayer body 4 is manufactured by a printing method, a sheet method, or the like. Furthermore, a binder removal process is performed, and the laminate 4 is obtained by firing under reducing firing conditions. The obtained laminate 4 is subjected to terminal polishing by barrel polishing or sand blasting, for example, by sputtering a metal, or by printing or transferring a terminal electrode paste produced in the same manner as the internal electrode paste, Electrodes 5 and 6 are formed.

  In the piezoelectric element having the above configuration, the internal electrode can be formed of an inexpensive electrode material such as Cu or Ni, so that the manufacturing cost can be greatly reduced. In addition, the piezoelectric layer 2 formed of the piezoelectric ceramic composition fired under the reduction firing condition has a small decrease in electric resistance at a high temperature and a small decrease in the electromechanical coupling coefficient kr. A piezoelectric element can be realized.

  Hereinafter, specific examples to which the present invention is applied will be described based on experimental results.

Experiment 1-1: Confirmation experiment of effect by addition of first subcomponent (MnO) In this experiment, Mn was added to the following main components so as to have a content shown in Table 1 in terms of MnO, The effect was investigated.
Main component: (Pb _0.995-0.03 Sr _0.03 ) [(Zn _1/3 Nb _2/3 ) _0.1 Ti _0.43 Zr _0.47 ] O ₃

The piezoelectric ceramic composition was produced as follows. First, PbO powder, SrCO ₃ powder, ZnO powder, Nb ₂ O ₅ powder, TiO ₂ powder, and ZrO ₂ powder were prepared as raw materials for the main component, and weighed so as to have the composition of the main component. Further, MnCO ₃ was prepared as an added species of Mn, and this was added to the main component composition so as to have the content shown in Table 1 in terms of MnO. Next, these raw materials were wet-mixed for 16 hours using a ball mill, and calcined at 700 ° C. to 900 ° C. for 2 hours in the air.

The obtained calcined product was finely pulverized and then wet pulverized for 16 hours using a ball mill. After drying this, an acrylic resin was added as a binder for granulation, and it was formed into a disk shape having a diameter of 17 mm and a thickness of 1 mm using a uniaxial press molding machine at a pressure of about 445 MPa. After molding, heat treatment was performed to volatilize the binder, and firing was performed at 950 ° C. for 2 hours to 8 hours in a low oxygen reduction atmosphere (oxygen partial pressure 1 × 10 ⁻¹⁰ to 1 × 10 ⁻⁶ atm). The obtained sintered body is sliced and lapped into a 0.6 mm thick disk, printed with silver paste on both sides, baked at 350 ° C, and an electric field of 3 kV in 120 ° C silicone oil for 15 minutes. Applied and subjected to polarization treatment.

  According to the above method, the amount of Mn (MnO) added was changed so as to have the content shown in Table 1, and Examples 1-1 to 1-6 and Comparative Examples 1-1 to 1-2 were produced. .

  About each produced Example and comparative example, electrical resistance IR was measured and the electromechanical coupling coefficient kr was further measured. The electromechanical coupling coefficient kr was measured using an impedance analyzer (HP4194A, manufactured by Hewlett-Packard Company). The results are shown in Table 1. In the table, the electric resistance IR (relative value) is a value obtained by dividing the resistance value at 150 ° C. in each example by the resistance value at 150 ° C. in the case of no addition (Comparative Example 1-1).

  As is apparent from Table 1, by containing MnO as the first subcomponent, the electrical resistance at a high temperature is greatly improved as compared with Comparative Example 1-1 in which the first subcomponent is not added. I understand. However, as in Comparative Example 1-2, when the content of MnO is too large, the degree of improvement in the electrical resistance IR at high temperatures is also reduced, and the reduction in the electromechanical coupling coefficient kr becomes remarkable, and the electromechanical coupling coefficient The value of kr is lower than the standard 50 (%). Therefore, when adding MnO, it can be said that the content is preferably 0.2% by mass or less.

Experiment 1-2: Study on the composition a of the main component A site element (first subcomponent: Mn)
The composition of the main component was as follows, and Examples 1-7 to 1-10 were produced by changing the composition a in the composition. The method for producing the piezoelectric ceramic composition is the same as in Experiment 1-1. For each of these examples, the electrical resistance IR (relative value) and the electromechanical coupling coefficient kr were measured as in Experiment 1-1. The results are shown in Table 2.
Main component: (Pb _{a -0.03} Sr _0.03 ) [(Zn _1/3 Nb _2/3 ) _0.1 Ti _0.43 Zr _0.47 ] O ₃

  As is apparent from Table 2, even when the composition a is changed within the range specified in the present invention, the effect of adding MnO can be obtained. In any of the examples, the electrical resistance at high temperature is large. It is improved and the decrease of the electromechanical coupling coefficient kr is suppressed.

Experiment 1-3: Study on the composition b of the A-site element as the main component (first subcomponent: Mn)
Examples 1-11 to 1-15 were produced by changing the composition b of the main component as follows and changing the composition b in the composition. The method for producing the piezoelectric ceramic composition is the same as in Experiment 1-1. For each of these Examples, the electrical resistance IR (relative value) and the electromechanical coupling coefficient kr were measured as in Experiment 1-1 and Experiment 2-1. The results are shown in Table 3.
Main component: (Pb _0.995-b Sr _b ) [(Zn _1/3 Nb _2/3 ) _0.1 Ti _0.43 Zr _0.47 ] O ₃

  As is apparent from Table 3, even when the composition b is changed within the range defined in the present invention, the effect of adding MnO can be obtained. In any of the examples, the electrical resistance at high temperature is large. It is improved and the decrease of the electromechanical coupling coefficient kr is suppressed.

Experiment 1-4: Study on A-site substitution element Me as the main component (first subcomponent: Mn)
Examples 1-16 and 1-17 were produced in the same manner as in Experiment 1-1 except that the main site A-site substitution element Me was changed to Ca or Ba. Table 4 shows the measurement results of the electrical resistance IR (relative value) and the electromechanical coupling coefficient kr at high temperatures in these examples.
Main component: (Pb _0.995-0.03 Me _0.03 ) [(Zn _1/3 Nb _2/3 ) _0.1 Ti _0.43 Zr _0.47 ] O ₃

  As is apparent from Table 4, even when the substitution element Me at the A site of the main component is changed from Sr to Ca or Ba, the effect of adding MnO is obtained, and the electrical resistance at high temperature is greatly improved. A decrease in the electromechanical coupling coefficient kr is suppressed.

Experiment 1-5: Study on composition x, y, z of B-site element as main component (first subcomponent: Mn)
The composition of the main component is as follows, and in this composition, the composition x, y, z of the B site element is changed as shown in Table 6, and Examples 1-18 to 1-23 and Comparative Example 1-2 are changed. Produced. The method for producing the piezoelectric ceramic composition is the same as in Experiment 1-1. For each of these examples, the electrical resistance IR (relative value) and electromechanical coupling coefficient kr at high temperature were measured as in Experiment 1-1. The results are shown in Table 5.
Main component: (Pb _a-0.03 Sr _0.03 ) [(Zn _1/3 Nb _2/3 ) _x Ti _y Zr _z ] O ₃

  As is apparent from Table 5, even when the composition x, y, z of the B site element is changed, the effect of adding MnO is obtained, the electrical resistance at high temperature is greatly improved, and the electromechanical coupling is achieved. It can be seen that the decrease in the coefficient kr is suppressed. However, in Comparative Example 1-2 in which the composition x, y, z of the B site element is outside the range defined in the present invention, the electromechanical coupling coefficient kr is small and is equal to or less than the reference value (50%).

Experiment 1-6: Study on addition of _second subcomponent (Ta ₂ O ₅ ) (first subcomponent: Mn)
Example 1-24 to Example 1-29 were prepared by adding Ta ₂ O ₅ as the second subcomponent and changing the amount of addition as shown in Table 6. The method for producing the piezoelectric ceramic composition is the same as in Experiment 1-1. For each of these examples, the electrical resistance IR (relative value) and electromechanical coupling coefficient kr at high temperature were measured as in Experiment 1-1. The results are shown in Table 6.

As is apparent from Table 6, even when Ta ₂ O ₅ is added as the second subcomponent, the effect of adding MnO is obtained, the electrical resistance at high temperature is greatly improved, and the electromechanical coupling coefficient kr The decline of the is suppressed. However, if the amount of Ta ₂ O ₅ added is too large, both the high temperature load life and the electromechanical coupling coefficient kr tend to decrease slightly.

Experiment 1-7: Study on type of second subcomponent (first subcomponent: Mn)
As the second subcomponent, the oxides shown in Table 7 were added in the addition amounts shown in Table 7 to prepare Examples 1-30 to 1-34. The method for producing the piezoelectric ceramic composition is the same as in Experiment 1-1. For each of these examples, the electrical resistance IR (relative value) and electromechanical coupling coefficient kr at high temperature were measured as in Experiment 1-1. The results are shown in Table 7.

  As is apparent from Table 7, it can be seen that the effect is observed in any additive and addition amount, the electrical resistance at high temperature is high, and the electromechanical coupling coefficient kr is also large.

Experiment 2-1: Confirmation experiment of effect by addition of first subcomponent (CoO) In this experiment, Co was added to the following main components so as to have a content shown in Table 8 in terms of CoO. Example 2-1 to Example 2-5 and Comparative examples 2-1 to 2-2 were prepared. The method for producing the piezoelectric ceramic composition was the same as in Experiment 1-1, and CoO was used as a raw material for the first subcomponent. For each of these Examples and Comparative Examples, the electrical resistance IR (relative value) and electromechanical coupling coefficient kr at high temperature were measured as in Experiment 1-1. The results are shown in Table 8.
Main component: (Pb _0.995-0.03 Sr _0.03 ) [(Zn _1/3 Nb _2/3 ) _0.1 Ti _0.43 Zr _0.47 ] O ₃

  As is apparent from Table 8, by including CoO as the first subcomponent, the electrical resistance at a high temperature is greatly improved as compared with Comparative Example 2-1 in which the first subcomponent is not added. I understand. However, as in Comparative Example 2-2, when the content of CoO is too large, the degree of improvement in electrical resistance IR at high temperatures is greatly reduced. Therefore, when adding the CoO, it can be said that the content is preferably 0.2% by mass or less.

Experiment 2-2: Study on the composition a of the main component A site element (first subcomponent: Co)
Example 2-6 to Example 2-9 were prepared by changing the composition a in the composition as follows. The method for producing the piezoelectric ceramic composition is the same as in Experiment 2-1. For each of these examples, the electrical resistance IR (relative value) and the electromechanical coupling coefficient kr were measured as in Experiment 2-1. The results are shown in Table 9.
Main component: (Pb _{a -0.03} Sr _0.03 ) [(Zn _1/3 Nb _2/3 ) _0.1 Ti _0.43 Zr _0.47 ] O ₃

  As can be seen from Table 9, even when the composition a is changed within the range specified in the present invention, the effect of adding CoO can be obtained. In any of the examples, the electrical resistance at high temperature is large. It is improved and the decrease of the electromechanical coupling coefficient kr is suppressed.

Experiment 2-3: Study on the composition b of the A-site element as the main component (first subcomponent: Co)
The composition of the main component was as follows, and Example 2-10 to Example 2-14 were prepared by changing the composition b in the composition. The method for producing the piezoelectric ceramic composition is the same as in Experiment 2-1. For each of these examples, the electrical resistance IR (relative value) and the electromechanical coupling coefficient kr were measured as in Experiment 2-1. The results are shown in Table 10.
Main component: (Pb _0.995-b Sr _b ) [(Zn _1/3 Nb _2/3 ) _0.1 Ti _0.43 Zr _0.47 ] O ₃

  As can be seen from Table 10, even when the composition b is changed within the range defined in the present invention, the effect of adding CoO is obtained, and in any of the examples, the electrical resistance at high temperature is large. It is improved and the decrease of the electromechanical coupling coefficient kr is suppressed.

Experiment 2-4: Study on A-site substitution element Me as the main component (first subcomponent: Co)
Example 2-15 and Example 2-16 were produced in the same manner as in Experiment 2-1, except that the main site A-site substitution element Me was changed to Ca or Ba. Table 11 shows the measurement results of the electrical resistance IR (relative value) and electromechanical coupling coefficient kr at high temperatures of these examples.
Main component: (Pb _0.995-0.03 Me _0.03 ) [(Zn _1/3 Nb _2/3 ) _0.1 Ti _0.43 Zr _0.47 ] O ₃

  As is clear from Table 11, even when the substitution element Me at the A site of the main component is changed from Sr to Ca or Ba, the effect of adding CoO is obtained, and the electrical resistance at high temperature is greatly improved. A decrease in the electromechanical coupling coefficient kr is suppressed.

Experiment 2-5: Study on the composition x, y, z of the B-site element as the main component (first subcomponent: Co)
The composition of the main component is as follows, and in this composition, the composition x, y, z of the B site element is changed as shown in Table 12, and Examples 2-17 to 2-22 and Comparative Example 2-2 are changed. Produced. The method for producing the piezoelectric ceramic composition is the same as in Experiment 2-1. For each of these Examples, the electrical resistance IR (relative value) and electromechanical coupling coefficient kr at high temperature were measured as in Experiment 2-1. The results are shown in Table 12.
Main component: (Pb _a-0.03 Sr _0.03 ) [(Zn _1/3 Nb _2/3 ) _x Ti _y Zr _z ] O ₃

  As apparent from Table 12, even when the composition x, y, z of the B site element is changed, the effect of adding CoO is obtained, the electrical resistance at high temperature is greatly improved, and the electromechanical coupling is achieved. It can be seen that the decrease in the coefficient kr is suppressed. However, in Comparative Example 2-2 in which the composition x, y, z of the B site element is out of the range defined in the present invention, the electromechanical coupling coefficient kr is small and is equal to or less than the reference value (50%).

Experiment 2-6: Study on addition of _second subcomponent (Ta ₂ O ₅ ) (first subcomponent: Co)
Example 2-23 to Example 2-28 were prepared by adding Ta ₂ O ₅ as the second subcomponent and changing the amount of addition as shown in Table 13. The method for producing the piezoelectric ceramic composition is the same as in Experiment 2-1. For each of these Examples, the electrical resistance IR (relative value) and electromechanical coupling coefficient kr at high temperature were measured as in Experiment 2-1. The results are shown in Table 13.

As is apparent from Table 13, even when Ta ₂ O ₅ is added as the second subcomponent, the effect of adding CoO is obtained, the electrical resistance at high temperature is greatly improved, and the electromechanical coupling coefficient kr The decline of the is suppressed. However, if the amount of Ta ₂ O ₅ added is too large, both the high temperature load life and the electromechanical coupling coefficient kr tend to decrease slightly.

Experiment 2-7: Study on type of second subcomponent (first subcomponent: Co)
As the second subcomponent, the oxides shown in Table 14 were added in the addition amounts shown in Table 14 to prepare Examples 2-29 to 2-33. The method for producing the piezoelectric ceramic composition is the same as in Experiment 2-1. For each of these Examples, the electrical resistance IR (relative value) and electromechanical coupling coefficient kr at high temperature were measured as in Experiment 2-1. The results are shown in Table 14.

  As is apparent from Table 14, it can be seen that the effect is observed in any additive and addition amount, the electrical resistance at high temperature is high, and the electromechanical coupling coefficient kr is also large.

Experiment 3-1: Confirmation experiment of effect by addition of first subcomponent (CrO) In this experiment, Cr was added to the following main components so as to have a content shown in Table 15 in terms of CrO. Example 3-1 to Example 3-6 and Comparative Examples 3-1 to 3-2 were produced. The method for producing the piezoelectric ceramic composition was the same as in Experiment 1-1, and Cr ₂ O ₃ was used as the first subcomponent material. For each of these Examples and Comparative Examples, the electrical resistance IR (relative value) and electromechanical coupling coefficient kr at high temperature were measured as in Experiment 1-1. The results are shown in Table 15.
Main component: (Pb _0.995-0.03 Sr _0.03 ) [(Zn _1/3 Nb _2/3 ) _0.1 Ti _0.43 Zr _0.47 ] O ₃

  As is apparent from Table 15, by containing CrO as the first subcomponent, the electrical resistance at a high temperature is greatly improved as compared with Comparative Example 3-1 in which the first subcomponent is not added. I understand. However, as in Comparative Example 3-2, when the content of CrO is too large, the degree of improvement in electrical resistance IR at high temperatures is greatly reduced. Therefore, it can be said that the content of CrO is preferably 0.2% by mass or less.

Experiment 3-2: Study on the composition a of the A-site element as the main component (first subcomponent: Cr)
Example 3-7 to Example 3-10 were prepared by changing the composition a in the composition as follows. The method for producing the piezoelectric ceramic composition is the same as in Experiment 3-1. For each of these examples, the electrical resistance IR (relative value) and the electromechanical coupling coefficient kr were measured as in Experiment 3-1. The results are shown in Table 16.
Main component: (Pb _{a -0.03} Sr _0.03 ) [(Zn _1/3 Nb _2/3 ) _0.1 Ti _0.43 Zr _0.47 ] O ₃

  As is apparent from Table 16, even when the composition a is changed within the range specified in the present invention, the effect of adding CrO is obtained. In any of the examples, the electrical resistance at high temperature is large. It is improved and the decrease of the electromechanical coupling coefficient kr is suppressed.

Experiment 3-3: Study on the composition b of the A-site element as the main component (first subcomponent: Cr)
Examples 3-11 to 3-15 were produced by changing the composition b of the main component as follows and changing the composition b in the composition. The method for producing the piezoelectric ceramic composition is the same as in Experiment 3-1. For each of these examples, the electrical resistance IR (relative value) and the electromechanical coupling coefficient kr were measured as in Experiment 3-1. The results are shown in Table 17.
Main component: (Pb _0.995-b Sr _b ) [(Zn _1/3 Nb _2/3 ) _0.1 Ti _0.43 Zr _0.47 ] O ₃

  As is clear from Table 17, even when the composition b is changed within the range defined in the present invention, the effect of adding CrO is obtained, and in any of the examples, the electrical resistance at high temperature is large. It is improved and the decrease of the electromechanical coupling coefficient kr is suppressed.

Experiment 3-4: Study on main component A-site substitution element Me (first subcomponent: Cr)
Example 3-16 and Example 3-17 were prepared in the same manner as in Experiment 3-1, except that the main site A-site substitution element Me was changed to Ca or Ba. Table 18 shows the measurement results of the electrical resistance IR (relative value) and the electromechanical coupling coefficient kr at high temperatures in these examples.
Main component: (Pb _0.995-0.03 Me _0.03 ) [(Zn _1/3 Nb _2/3 ) _0.1 Ti _0.43 Zr _0.47 ] O ₃

  As is apparent from Table 18, even when the substitution element Me at the A site of the main component is changed from Sr to Ca or Ba, the effect of adding CrO is obtained, and the electrical resistance at high temperature is greatly improved. A decrease in the electromechanical coupling coefficient kr is suppressed.

Experiment 3-5: Study on composition x, y, z of B site element as main component (first subcomponent: Cr)
The composition of the main component is as follows, and in this composition, the composition x, y, z of the B site element is changed as shown in Table 19, and Examples 3-18 to 3-23 and Comparative Example 3-2 are changed. Produced. The method for producing the piezoelectric ceramic composition is the same as in Experiment 3-1. For each of these Examples, the electrical resistance IR (relative value) and electromechanical coupling coefficient kr at high temperature were measured as in Experiment 3-1. The results are shown in Table 19.
Main component: (Pb _a-0.03 Sr _0.03 ) [(Zn _1/3 Nb _2/3 ) _x Ti _y Zr _z ] O ₃

  As apparent from Table 19, even when the composition x, y, z of the B site element is changed, the effect of adding CrO is obtained, the electrical resistance at high temperature is greatly improved, and the electromechanical coupling is achieved. It can be seen that the decrease in the coefficient kr is suppressed. However, in Comparative Example 3-2 in which the composition x, y, z of the B site element deviates from the range defined in the present invention, the electromechanical coupling coefficient kr is small and is equal to or less than the reference value (50%).

Experiment 3-6: Study on addition of _second subcomponent (Ta ₂ O ₅ ) (first subcomponent: Cr)
Example 3-24 to Example 3-29 were prepared by adding Ta ₂ O ₅ as the second subcomponent and changing the addition amount as shown in Table 20. The method for producing the piezoelectric ceramic composition is the same as in Experiment 3-1. For each of these Examples, the electrical resistance IR (relative value) and electromechanical coupling coefficient kr at high temperature were measured as in Experiment 3-1. The results are shown in Table 20.

As can be seen from Table 20, even when Ta ₂ O ₅ is added as the second subcomponent, the effect of adding CrO is obtained, the electrical resistance at high temperature is greatly improved, and the electromechanical coupling coefficient kr The decline of the is suppressed. However, if the amount of Ta ₂ O ₅ added is too large, both the high temperature load life and the electromechanical coupling coefficient kr tend to decrease slightly.

Experiment 3-7: Study on type of second subcomponent (first subcomponent: Cr)
As a 2nd subcomponent, the oxide shown in Table 21 was added with the addition amount shown in Table 21, and Example 3-30-Example 3-34 were produced. The method for producing the piezoelectric ceramic composition is the same as in Experiment 3-1. For each of these Examples, the electrical resistance IR (relative value) and electromechanical coupling coefficient kr at high temperature were measured as in Experiment 3-1. The results are shown in Table 21.

  As is apparent from Table 21, it can be seen that the effect is observed in any additive and addition amount, the electrical resistance at high temperature is high, and the electromechanical coupling coefficient kr is also large.

Experiment 4-1: Experiment for confirming effect by addition of first subcomponent (FeO) In this experiment, Fe was added to the following main components so as to have the content shown in Table 22 in terms of FeO. Example 4-1 to Example 4-6 and Comparative examples 4-1 to 4-2 were prepared. The method for producing the piezoelectric ceramic composition was the same as in Experiment 1-1, and Fe ₂ O ₃ was used as the first subcomponent material. For each of these Examples and Comparative Examples, the electrical resistance IR (relative value) and electromechanical coupling coefficient kr at high temperature were measured as in Experiment 1-1. The results are shown in Table 22.
Main component: (Pb _0.995-0.03 Sr _0.03 ) [(Zn _1/3 Nb _2/3 ) _0.1 Ti _0.43 Zr _0.47 ] O ₃

  As is apparent from Table 22, by including FeO as the first subcomponent, the electrical resistance at a high temperature is greatly improved as compared with Comparative Example 4-1, in which the first subcomponent is not added. I understand. However, as in Comparative Example 4-2, when the content of FeO is too large, the degree of improvement in electrical resistance IR at high temperatures is greatly reduced. Therefore, it can be said that the content of FeO is preferably 0.2% by mass or less.

Experiment 4-2: Study on the composition a of the A-site element as the main component (first subcomponent: Fe)
Example 4-7 to Example 4-10 were prepared by changing the composition a in the composition as follows. The method for producing the piezoelectric ceramic composition is the same as in Experiment 4-1. For each of these examples, the electrical resistance IR (relative value) and the electromechanical coupling coefficient kr were measured as in Experiment 4-1. The results are shown in Table 23.
Main component: (Pb _{a -0.03} Sr _0.03 ) [(Zn _1/3 Nb _2/3 ) _0.1 Ti _0.43 Zr _0.47 ] O ₃

  As is clear from Table 23, even when the composition a is changed within the range specified in the present invention, the effect of adding FeO is obtained, and in any of the examples, the electrical resistance at high temperature is large. It is improved and the decrease of the electromechanical coupling coefficient kr is suppressed.

Experiment 4-3: Study on the composition b of the A-site element as the main component (first subcomponent: Fe)
Examples 4-11 to Examples 4-15 were prepared by changing the composition b of the main component as follows. The method for producing the piezoelectric ceramic composition is the same as in Experiment 4-1. For each of these examples, the electrical resistance IR (relative value) and the electromechanical coupling coefficient kr were measured as in Experiment 4-1. The results are shown in Table 24.
Main component: (Pb _0.995-b Sr _b ) [(Zn _1/3 Nb _2/3 ) _0.1 Ti _0.43 Zr _0.47 ] O ₃

  As is apparent from Table 24, even when the composition b is changed within the range specified in the present invention, the effect of adding FeO can be obtained. In any of the examples, the electrical resistance at high temperature is large. It is improved and the decrease of the electromechanical coupling coefficient kr is suppressed.

Experiment 4-4: Study on main component A-site substitution element Me (first subcomponent: Fe)
Example 4-16 and Example 4-17 were prepared in the same manner as in Experiment 4-1, except that the main site A-site substitution element Me was changed to Ca or Ba. Table 25 shows the measurement results of the electrical resistance IR (relative value) and the electromechanical coupling coefficient kr at high temperatures in these examples.
Main component: (Pb _0.995-0.03 Me _0.03 ) [(Zn _1/3 Nb _2/3 ) _0.1 Ti _0.43 Zr _0.47 ] O ₃

  As is apparent from Table 25, when the substitution element Me at the A site of the main component is changed from Sr to Ca or Ba, the effect of adding FeO is obtained, and the electrical resistance at high temperature is greatly improved. A decrease in the electromechanical coupling coefficient kr is suppressed.

Experiment 4-5: Study on the composition x, y, z of the B-site element as the main component (first subcomponent: Fe)
The composition of the main component is as follows, and in this composition, the composition x, y, z of the B site element is changed as shown in Table 26, and Examples 4-18 to 4-23 and Comparative Example 4-2 are changed. Produced. The method for producing the piezoelectric ceramic composition is the same as in Experiment 4-1. For each of these examples, the electrical resistance IR (relative value) at high temperature and the electromechanical coupling coefficient kr were measured as in Experiment 4-1. The results are shown in Table 26.
Main component: (Pb _a-0.03 Sr _0.03 ) [(Zn _1/3 Nb _2/3 ) _x Ti _y Zr _z ] O ₃

  As apparent from Table 26, even when the composition x, y, z of the B site element is changed, the effect of adding FeO is obtained, the electrical resistance at high temperature is greatly improved, and the electromechanical coupling is achieved. It can be seen that the decrease in the coefficient kr is suppressed. However, in Comparative Example 4-2 in which the composition x, y, z of the B site element is outside the range defined in the present invention, the electromechanical coupling coefficient kr is small and is equal to or less than the reference value (50%).

Experiment 4-6: Study on addition of _second subcomponent (Ta ₂ O ₅ ) (first subcomponent: Fe)
Example 4-24 to Example 4-29 were prepared by adding Ta ₂ O ₅ as the second subcomponent and changing the amount of addition as shown in Table 27. The method for producing the piezoelectric ceramic composition is the same as in Experiment 4-1. For each of these examples, the electrical resistance IR (relative value) at high temperature and the electromechanical coupling coefficient kr were measured as in Experiment 4-1. The results are shown in Table 27.

As is apparent from Table 27, even when Ta ₂ O ₅ is added as the second subcomponent, the effect of adding FeO is obtained, the electrical resistance at high temperature is greatly improved, and the electromechanical coupling coefficient kr The decline of the is suppressed. However, if the amount of Ta ₂ O ₅ added is too large, both the high temperature load life and the electromechanical coupling coefficient kr tend to decrease slightly.

Experiment 4-7: Study on type of second subcomponent (first subcomponent: Fe)
As a 2nd subcomponent, the oxide shown in Table 28 was added with the addition amount shown in Table 28, and Example 4-30-Example 4-34 were produced. The method for producing the piezoelectric ceramic composition is the same as in Experiment 4-1. For each of these examples, the electrical resistance IR (relative value) at high temperature and the electromechanical coupling coefficient kr were measured as in Experiment 4-1. The results are shown in Table 28.

  As is clear from Table 28, it can be seen that the effect is observed in any additive and addition amount, the electrical resistance at high temperature is high, and the electromechanical coupling coefficient kr is also large.

Experiment 5-1: Confirmation experiment of effect by addition of first subcomponent (NiO) In this experiment, Ni was added to the following main components so as to have a content shown in Table 29 in terms of NiO. Example 5-1 to Example 5-6 and Comparative Examples 5-1 to 5-2 were prepared. The method for producing the piezoelectric ceramic composition was the same as in Experiment 1-1, and NiO was used as a raw material for the first subcomponent. For each of these Examples and Comparative Examples, the electrical resistance IR (relative value) and electromechanical coupling coefficient kr at high temperature were measured as in Experiment 1-1. The results are shown in Table 29.
Main component: (Pb _0.995-0.03 Sr _0.03 ) [(Zn _1/3 Nb _2/3 ) _0.1 Ti _0.43 Zr _0.47 ] O ₃

  As is apparent from Table 29, by containing NiO as the first subcomponent, the electrical resistance at a high temperature is greatly improved as compared with Comparative Example 5-1, in which the first subcomponent is not added. I understand. However, as in Comparative Example 5-2, when the content of NiO is too large, the degree of improvement in electrical resistance IR at high temperatures is greatly reduced. Therefore, it can be said that the content of NiO is preferably 0.2% by mass or less.

Experiment 5-2: Study on the composition a of the main component A site element (first subcomponent: Ni)
Examples 5-7 to 5-10 were prepared by changing the composition a in the composition as follows. The method for producing the piezoelectric ceramic composition is the same as in Experiment 5-1. For each of these examples, the electrical resistance IR (relative value) and the electromechanical coupling coefficient kr were measured as in Experiment 5-1. The results are shown in Table 30.
Main component: (Pb _{a -0.03} Sr _0.03 ) [(Zn _1/3 Nb _2/3 ) _0.1 Ti _0.43 Zr _0.47 ] O ₃

  As is apparent from Table 30, even when the composition a is changed within the range specified in the present invention, the effect of adding NiO is obtained, and in any of the examples, the electrical resistance at high temperature is large. It is improved and the decrease of the electromechanical coupling coefficient kr is suppressed.

Experiment 5-3: Study on the composition b of the A-site element as the main component (first subcomponent: Ni)
Examples 5-11 to 5-15 were prepared by changing the composition b of the main component as follows. The method for producing the piezoelectric ceramic composition is the same as in Experiment 5-1. For each of these examples, the electrical resistance IR (relative value) and the electromechanical coupling coefficient kr were measured as in Experiment 5-1. The results are shown in Table 31.
Main component: (Pb _0.995-b Sr _b ) [(Zn _1/3 Nb _2/3 ) _0.1 Ti _0.43 Zr _0.47 ] O ₃

  As can be seen from Table 31, even when the composition b is changed within the range specified in the present invention, the effect of adding NiO can be obtained. In any of the examples, the electrical resistance at high temperature is large. It is improved and the decrease of the electromechanical coupling coefficient kr is suppressed.

Experiment 5-4: Study on main component A-site substitution element Me (first subcomponent: Fe)
Examples 5-16 and 5-17 were produced in the same manner as in Experiment 5-1, except that the main site A-site substitution element Me was changed to Ca or Ba. Table 32 shows the measurement results of the electrical resistance IR (relative value) and the electromechanical coupling coefficient kr at high temperatures in these examples.
Main component: (Pb _0.995-0.03 Me _0.03 ) [(Zn _1/3 Nb _2/3 ) _0.1 Ti _0.43 Zr _0.47 ] O ₃

  As is clear from Table 32, when the substitution element Me at the A site of the main component is changed from Sr to Ca or Ba, the effect of adding NiO is obtained, and the electrical resistance at high temperature is greatly improved. A decrease in the electromechanical coupling coefficient kr is suppressed.

Experiment 5-5: Study on the composition x, y, z of the B-site element as the main component (first subcomponent: Fe)
The composition of the main component is as follows, and in this composition, the composition x, y, z of the B site element is changed as shown in Table 33, and Examples 5-18 to 5-23 and Comparative Example 5-2 are changed. Produced. The method for producing the piezoelectric ceramic composition is the same as in Experiment 5-1. For each of these Examples, the electrical resistance IR (relative value) at high temperature and the electromechanical coupling coefficient kr were measured as in Experiment 5-1. The results are shown in Table 33.
Main component: (Pb _a-0.03 Sr _0.03 ) [(Zn _1/3 Nb _2/3 ) _x Ti _y Zr _z ] O ₃

  As apparent from Table 33, even when the composition x, y, z of the B site element is changed, the effect of adding NiO is obtained, the electrical resistance at high temperature is greatly improved, and the electromechanical coupling is achieved. It can be seen that the decrease in the coefficient kr is suppressed. However, in Comparative Example 5-2 in which the composition x, y, z of the B site element is outside the range defined in the present invention, the electromechanical coupling coefficient kr is small and is equal to or less than the reference value (50%).

Experiment 5-6: Study on addition of _second subcomponent (Ta ₂ O ₅ ) (first subcomponent: Ni)
Example 5-24 to Example 5-29 were prepared by adding Ta ₂ O ₅ as the second subcomponent and changing the addition amount as shown in Table 34. The method for producing the piezoelectric ceramic composition is the same as in Experiment 5-1. For each of these Examples, the electrical resistance IR (relative value) at high temperature and the electromechanical coupling coefficient kr were measured as in Experiment 5-1. The results are shown in Table 34.

As is apparent from Table 34, even when Ta ₂ O ₅ is added as the second subcomponent, the effect of adding NiO is obtained, the electrical resistance at high temperature is greatly improved, and the electromechanical coupling coefficient kr The decline of the is suppressed. However, if the amount of Ta ₂ O ₅ added is too large, both the high temperature load life and the electromechanical coupling coefficient kr tend to decrease slightly.

Experiment 5-7: Study on type of second subcomponent (first subcomponent: Ni)
As the second subcomponent, the oxides shown in Table 35 were added in the addition amounts shown in Table 35 to prepare Examples 5-30 to 5-34. The method for producing the piezoelectric ceramic composition is the same as in Experiment 5-1. For each of these Examples, the electrical resistance IR (relative value) at high temperature and the electromechanical coupling coefficient kr were measured as in Experiment 5-1. The results are shown in Table 35.

  As is apparent from Table 35, it can be seen that the effect is observed in any additive and addition amount, the electrical resistance at high temperature is high, and the electromechanical coupling coefficient kr is also large.

Experiment 6-1: Confirmation of effect by annealing treatment For each of the examples and comparative examples prepared in Experiments 1-1, 2-1, 3-1, 4-1, 5-1 above, after firing, the temperature was 700 ° C. Annealing treatment was performed under conditions of oxygen partial pressure of 2 × 10 ⁻⁵ atm and 2 hours. Tables 36 to 40 show the electrical resistance IR (relative value) after the annealing treatment.

  As is clear from these tables, a particularly remarkable electrical resistance IR improvement effect was recognized when Mn, Co, and Ni were used as the first subcomponent. Further, the value of the electromechanical coupling coefficient kr hardly changed depending on the presence or absence of the annealing treatment.

It is a schematic sectional drawing which shows one structural example of a laminated actuator.

Explanation of symbols

1 Laminated actuator, 2 piezoelectric layers, 3 internal electrodes, 4 laminated bodies, 5 and 6 terminal electrodes

Claims (11)

A piezoelectric ceramic composition mainly composed of a composite oxide containing Pb, Ti, and Zr as constituent elements,
It contains at least one selected from Mn, Co, Cr, Fe and Ni as the first subcomponent, and the content of the first subcomponent is 0.2% by mass or less in terms of oxide (however, 0 is not included) A piezoelectric ceramic composition characterized by the following: 2. The piezoelectric ceramic composition according to claim 1, wherein the piezoelectric ceramic composition is fired under reducing firing conditions. 3. The piezoelectric ceramic composition according to claim 2, wherein the reduction firing conditions are a firing temperature of 800 ° C. to 1200 ° C. and an oxygen partial pressure of 1 × 10 ⁻¹⁰ to 1 × 10 ⁻⁶ atm. As the main component, Pb _a [(Zn _1/3 Nb _2/3 ) _x Ti _y Zr _z ] O ₃ (where 0.96 ≦ a ≦ 1.03, 0.05 ≦ x ≦ 0.15, 0 25 ≦ y ≦ 0.5, 0.35 ≦ z ≦ 0.6, and x + y + z = 1.), And (Pb _a−b Me _b ) [(Zn _1/3 Nb _{2/3) x Ti y Zr z]} O 3 ( however, 0.96 ≦ a ≦ 1.03,0 <b ≦ 0.1,0.05 ≦ x ≦ 0.15,0.25 ≦ y ≦ 0 0.5, 0.35 ≦ z ≦ 0.6, and x + y + z = 1, and Me in the formula represents at least one selected from Sr, Ca, and Ba.) The piezoelectric ceramic composition according to any one of claims 1 to 3, comprising at least one selected from the group.   It contains at least one selected from Ta, Sb, Nb and W as the second subcomponent, and the content of the second subcomponent is 1.0% by mass or less in terms of oxide. Item 5. The piezoelectric ceramic composition according to any one of Items 1 to 4. A method for producing a piezoelectric ceramic composition mainly comprising a composite oxide containing Pb, Ti and Zr as constituent elements,
A piezoelectric ceramic composition characterized in that an additive species including at least one selected from Mn, Co, Cr, Fe, and Ni is added to the raw material matrix composition of the composite oxide and fired under reducing firing conditions. Production method. The method for producing a piezoelectric ceramic composition according to claim 6, wherein the reducing firing conditions are a firing temperature of 800 ° C. to 1200 ° C. and an oxygen partial pressure of 1 × 10 ⁻¹⁰ to 1 × 10 ⁻⁶ atm.   8. The method of manufacturing a piezoelectric ceramic composition according to claim 6, wherein annealing is performed after the firing.   A piezoelectric element using the piezoelectric ceramic composition according to any one of claims 1 to 5.   The piezoelectric element according to claim 9, comprising a plurality of piezoelectric layers containing the piezoelectric ceramic composition and a plurality of internal electrodes inserted between the piezoelectric layers.   The piezoelectric element according to claim 10, wherein the internal electrode contains Cu or Ni.

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