KR20230139821A - Pzt based piezoelectric material with excellent low temperature sintering properties - Google Patents

Abstract

Disclosed is a PZT series piezoelectric material with excellent sintering properties at low temperatures.
The piezoelectric material according to the present invention may have a composition including a composite perovskite structure and additives in a perovskite-structured PZT material. Preferably, the piezoelectric material of the present invention has a composition of (1-x)Pb(Zr _1-a Ti _a )O ₃ - xPb(B ¹ _1/3 Nb _2/3 )O ₃ + additive, and B ¹ is Zn. , Ni, and Mg may be included. (However, 0.15 ≤ x ≤ 0.25, 0.50 ≤ a ≤ 0.54.)

Description

PZT series piezoelectric material with excellent low-temperature sintering properties {PZT BASED PIEZOELECTRIC MATERIAL WITH EXCELLENT LOW TEMPERATURE SINTERING PROPERTIES}

The present invention relates to a PZT series piezoelectric material that has excellent sintering properties at low temperatures of 950°C or lower.

Piezoelectric materials are materials in which mechanical energy and electrical energy are mutually converted, and are applied to piezoelectric sensors, speakers, and haptic devices.

As a piezoelectric material, a Pb(Zr, Ti)O ₃ (hereinafter referred to as PZT)-based ceramic composition with a perovskite structure and lead as a main component is mainly used.

Because these piezoelectric materials are difficult to sinter at low temperatures, they are used together with expensive electrode materials such as Ag-Pd. However, since Pd is very expensive, attempts are being made to use low-cost electrodes such as Cu and Ni to reduce the cost of piezoelectric materials.

In order to use electrodes such as Cu or Ni in piezoelectric materials, the piezoelectric materials must be sintered at a low temperature of 950°C or lower while maintaining the existing piezoelectric properties.

Meanwhile, piezoelectric materials can be classified into hard materials and soft materials. Hard materials have a high mechanical quality factor Q _m and thus have good frequency response characteristics. On the other hand, soft materials have a high piezoelectric constant _d33 , so they are prone to mechanical deformation. Hard materials are structurally more stable and durable than soft materials, so they are widely used in various applications such as sensors and oscillators.

The standard for evaluating these hard materials is the mechanical quality factor Q _m , and a material can be called a hard material only when Q _m is high. Additionally, in order to use piezoelectric materials in piezoelectric devices, the electromechanical coupling coefficient (interconversion rate) k _p must be basically high.

Therefore, a good hard material must satisfy both high Q _m and k _p .

However, since k _p is close to the characteristics of soft materials, it is not easy to satisfy both high k _p and Q _m . In addition, in order for the piezoelectric material to be used with low-cost electrodes such as Cu and Ni, low-temperature sintering must be possible.

Therefore, in order to use low-cost electrodes, research is needed on piezoelectric materials that have both excellent k _p and Q _m and are capable of low-temperature sintering.

The purpose of the present invention is to provide a PZT series piezoelectric material that can be sintered at a low temperature of 950°C or lower.

Another object of the present invention is to provide a PZT series piezoelectric material with a high mechanical quality coefficient Q _m .

Another object of the present invention is to provide a PZT series piezoelectric material with a high electromechanical coupling coefficient k _p .

Another object of the present invention is to provide a piezoelectric element including low-cost electrodes such as Ni and Cu and the above PZT series piezoelectric material.

The objects of the present invention are not limited to the objects mentioned above, and other objects and advantages of the present invention that are not mentioned can be understood by the following description and will be more clearly understood by the examples of the present invention. Additionally, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof indicated in the patent claims.

The piezoelectric material according to the present invention may have a composition including a PZT material with a perovskite structure, a relaxer with a composite perovskite structure, and an additive.

The piezoelectric material has a composition of (1-x)Pb(Zr _1-a Ti _a )O ₃ - xPb(B ¹ _1/3 Nb _2/3 )O ₃ + additives, and B ¹ is Zn, Ni, and Mg. It may include one or more types.

(However, 0.15 ≤ x ≤ 0.25, 0.50 ≤ a ≤ 0.54.)

The additive may include one or more of MnO ₂ , Li ₂ O and Fe ₂ O ₃ , and specifically may include y at% MnO ₂ , z at% Li ₂ O, and w at% Fe ₂ O ₃ there is.

(However, 1.1 ≤ y ≤ 3.7, 0 ≤ z ≤ 4.4, 0 ≤ w ≤ 2.0.)

The piezoelectric material according to the present invention has a composition including one or more additives among MnO ₂ , Li ₂ O and Fe ₂ O ₃ , so that it can be sintered at a low temperature of 950°C or lower and has high k _p and Q _m values. There are visible advantages.

In addition, the piezoelectric material of the present invention has a high mechanical quality coefficient Q _m and an electromechanical coupling coefficient k _p , so it has the advantage of being applicable to piezoelectric devices that require a hard-type piezoelectric material that is structurally stable and has excellent durability.

Furthermore, the piezoelectric material of the present invention can be used with low-cost electrodes, which has the advantage of providing a cost reduction effect in manufacturing piezoelectric devices containing the piezoelectric material.

In addition to the above-described effects, specific effects of the present invention are described below while explaining specific details for carrying out the invention.

The above-described objects, features, and advantages are described in detail below with reference to the attached tables and examples, so that those skilled in the art will be able to easily implement the technical idea of the present invention. . In describing the present invention, if it is determined that a detailed description of known technologies related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the attached table. In the table, identical reference signs are used to indicate identical or similar components.

Hereinafter, the “top (or bottom)” of a component or the arrangement of any component on the “top (or bottom)” of a component means that any component is placed in contact with the top (or bottom) of the component. Additionally, it may mean that other components may be interposed between the component and any component disposed on (or under) the component.

Additionally, when a component is described as being “connected,” “coupled,” or “connected” to another component, the components may be directly connected or connected to each other, but the other component is “interposed” between each component. It should be understood that “or, each component may be “connected,” “combined,” or “connected” through other components.

Hereinafter, a PZT series piezoelectric material with excellent low-temperature sintering characteristics according to some embodiments of the present invention will be described.

In the present invention, in order to use low-cost electrodes for piezoelectric materials, a piezoelectric ceramic composition that can be sintered at a low temperature of 950°C or lower was studied.

The piezoelectric material of the present invention has a composition including a PZT material, a relaxer with a composite perovskite structure, and one or more additives among MnO ₂ , Li ₂ O, and Fe ₂ O ₃ , and the additive lowers the sintering temperature and improves mechanical quality. The coefficient Q _m can be increased.

Among the piezoelectric materials of the present invention, PZT has a perovskite (ABO ₃ ) structure, where Pb is located at the A site and Zr and Ti are located at the B site. Depending on the molar ratio of Pb, Zr, and Ti, the crystal structure at low or high temperatures can be controlled to improve dielectric and piezoelectric properties.

Among the piezoelectric materials of the present invention, the relaxer has a composite perovskite [A(B ^Ⅰ B ^Ⅱ )O ₃ ] structure, where Pb is located at the A site, and at least one of Zn, Ni, and Mg is located at the B ^Ⅰ site. , Nb is located at the B ^II site.

The piezoelectric material of the present invention preferably has a composition of (1-x)Pb(Zr _1-a Ti _a )O ₃ - xPb(B ¹ _1/3 Nb _2/3 )O ₃ + additive.

And B ¹ preferably includes one or more of Zn, Ni, and Mg.

Here, 0.15 ≤ x ≤ 0.25, 0.50 ≤ a ≤ 0.54. Specifically, a is 0.525 ≤ a ≤ 0.530.

In the composition of the piezoelectric material, the additive may include one or more of MnO ₂ , Li ₂ O, and Fe ₂ O ₃ . Specifically, the additive is y at% MnO ₂ , It may include one or more of z at% Li ₂ O and w at% Fe ₂ O ₃ .

Here, y, z, and w are each 1.1 ≤ y ≤ 3.7, 0 ≤ z ≤ 4.4, and 0 ≤ w ≤ 2.0.

Specifically, y is 1.1 ≤ y ≤ 2.6.

z is 0.9 ≤ z ≤ 4.4, 0 ≤ z ≤ 3.5, preferably 0.9 ≤ z ≤ 3.5, and more preferably 0 ≤ z ≤ 1.8.

w is 0.4 ≤ w ≤ 2.0, 0 ≤ w ≤ 1.8, 0 ≤ w ≤ 1.2, 0.4 ≤ w ≤ 1.2, preferably 0 ≤ w ≤ 0.8, and more preferably 0.4 ≤ w ≤ 0.8.

As the a, x, y, z, and w satisfy the above range, the electromechanical coupling coefficient k _p of the piezoelectric material can represent 0.50 ≤ k _p , and the mechanical quality coefficient Q _m of the piezoelectric material can be 500 < Q _m . It can be expressed.

Preferably, k _p may be 0.50 < k _p , more preferably 0.50 ≤ k _p < 0.70, and even more preferably 0.50 ≤ k _p ≤ 0.64.

Preferably, Q _m may be 500 < Q _m < 4300, and more preferably 521 ≤ Q _m < 4276.

Electromechanical coupling coefficient (interconversion rate) k _p and mechanical quality coefficient Q _m are used as criteria for evaluating hard materials, and by satisfying 0.50 ≤ k _p and 500 < Q _m , piezoelectric materials can be used in piezoelectric devices that require hard properties. can be used

As such, the piezoelectric material of the present invention contains a composition containing PZT and a relaxer, as well as one or more additives among MnO ₂ , Li ₂ O and Fe ₂ O ₃ , thereby increasing the mechanical quality coefficient Q _m of the piezoelectric material and maintaining a temperature range of 950°C. By increasing the sintering density of the piezoelectric material sintered at a low temperature below, the electromechanical coupling coefficient k _p can be increased. Accordingly, piezoelectric materials have the advantage of being applicable to hard-type piezoelectric materials that are structurally stable and have excellent durability.

The method of manufacturing the piezoelectric material of the present invention may include mixing raw materials, drying, calcining, pulverizing the calcined powder, drying, molding, and sintering.

In the step of mixing the raw materials, the raw material powders and solvents such as water, alcohol, and 2-propanol can be used to wet grind them by ball milling for 2 to 72 hours, and the solvent can be removed in the drying step.

The raw material powder of Pb(Zr _1-a Ti _a )O ₃ can be PbO, ZrO ₂ , and TiO ₂ , and the raw material powder of Pb(B ¹ _1/3 Nb _2/3 )O ₃ can be PbO, ZnO, and NiO. , MgO can be used. And the additive may be one or more of MnO ₂ , Li ₂ O and Fe ₂ O ₃ .

Subsequently, for phase synthesis, the dried result was calcinated at a temperature of 700 to 1000°C for 30 minutes to 5 hours to obtain (1-x)Pb(Zr _1-a Ti _a )O ₃ - xPb(B ¹ _{1 /3} Nb _2/3 )O ₃ + A material having an additive composition can be manufactured.

Next, in order to improve density by minimizing the powder particle size of the material, the calcined powder is wet-ground for 2 to 72 hours by ball milling using solvents such as water, alcohol, and 2-propanol, and then dried. Solvent can be removed.

Next, the dried result was press-molded into a disk shape with a diameter of 15 to 20 mm and a thickness of 1 to 2 mm, and then sintered at 800 to 1,200°C for 30 minutes to 5 hours to produce (1-x)Pb(Zr _1-a Ti). _a )O ₃ - xPb(B ¹ _1/3 Nb _2/3 )O ₃ + A piezoelectric material with an additive composition can be manufactured.

Specific examples of the piezoelectric material having excellent low-temperature sintering characteristics are as follows.

1. Manufacturing of piezoelectric materials

Raw material powders with composition ratios shown in Tables 1 to 17 below, PbO, ZrO ₂ , TiO ₂ , ZnO, NiO, MgO, additives MnO ₂ , Li ₂ CO ₃ , Fe ₂ O ₃ and 2-propanol solvent were mixed by ball milling. After wet grinding for 24 hours, the solvent was removed by drying.

The dried result was calcined at 850°C for 3 hours to produce a material with the composition (1-x)Pb(Zr _1-a Ti _a )O ₃ - xPb(B ¹ _1/3 Nb _2/3 )O ₃ + additives. Manufactured. Among additives, Li ₂ CO ₃ is changed to Li ₂ O when CO ₂ is removed during the calcination process.

Next, the calcined material and the 2-propanol solvent were wet-ground by ball milling for 24 hours, and then dried to remove the solvent.

Subsequently, the dried result was press-molded into a disk shape with a diameter of 18 mm and a thickness of 1.6 mm, and then sintered at 950°C for 2 hours to produce (1-x)Pb(Zr _1-a Ti _a )O ₃ - xPb(B A piezoelectric material with an additive composition of ¹ _1/3 Nb _2/3 )O ₃ + was manufactured. The composition ratios of the manufactured piezoelectric materials are listed in Tables 1 to 17.

2. Physical property evaluation method and results

In order to evaluate the physical properties, it was lapped or polished to a thickness of 1 mm. In order to coat the upper and lower parts of the manufactured piezoelectric material with electrodes, metal electrodes were formed with Ag paste for 600°C and heat treated at 600°C for 30 minutes. .

Poling was performed at 120°C for 0.5 to 2 hours at 3 to 5 kV/mm, and the characteristics were evaluated after aging for more than 24 hours.

1) Density measurement: Measured using the Archimedes method using xylene.

2) Measurement of ε ^T ₃₃ /ε _{0 :} Using an impedance analyzer (4294A, Agilent Technologies, Santa Clara, CA), the frequency was fixed to 1 kHz and the capacitance ( C ) was measured.

Here, C: capacitance, r: radius of the specimen, d: thickness of the specimen, ε ₀ : represents the permittivity of vacuum.

3) Piezoelectric charge coefficient d ₃₃ (pC/N) measurement: Measured using a Micro-Epsilon Channel Product DT-3300 measuring device.

4) Measurement of electromechanical coupling coefficient k _p : The resonance frequency (f _r ) and anti-resonance frequency (f _a ) were measured at 0.1 V in the frequency band of 200 kHz to 500 kHz using an impedance analyzer (4294A). The electromechanical coupling coefficient (k _p ) was calculated using the following formula.

Here, f _r and f _a are the resonant frequency and anti-resonant frequency, respectively.

5) Measurement of mechanical quality factor Q _m : Resonant frequency (f _r ), anti-resonant frequency (f _a ), and resistance at the resonant frequency at 0.1 V in the frequency range of 200 kHz to 500 kHz using an impedance analyzer (4294A). (R) was measured.

The mechanical quality factor (Q _m ) was calculated using the following formula.

Here, f _r and f _a are the resonant frequency and anti-resonant frequency, respectively, R is the resistance value at the resonant frequency, and C is the capacitance.

Table 1 below shows a composition containing only PZT in the form of (1-x)PZT-xPMNN and a relaxer, 0.8Pb(Zr _1-a Ti _a )O ₃ -0.2Pb(Mg _0.5 Ni _0.5 ) _1/3 Nb ₂ This is a comparative example having a composition of _/3 O ₃ (0.50≤a≤0.54).

[Table 1]

In Comparative Examples 1 to 5, the density, ε ^T ₃₃ /ε ₀ , piezoelectric constant d ₃₃ , electromechanical coupling coefficient k _p , and mechanical quality factor Q _m showed a tendency according to the a value shown by general PZT series materials. Since one or more additives among MnO ₂ , Li ₂ O and Fe ₂ O ₃ that have the effect of improving Q _m were not added, the mechanical quality coefficient Q _m was very low, below 124.

Therefore, it can be seen that the mechanical quality coefficient Q _m of Comparative Examples 1 to 5 is low to be used as a hard material, so the Q _m value needs to be improved.

The ε ^T ₃₃ /ε ₀ is a characteristic indicating dielectricity, and when a piezoelectric material is used as a device, the lower the ε ^T ₃₃ /ε ₀ , the faster the reaction speed, so it is advantageous to keep the value below 2000.

The example compositions described below all have an ε ^T ₃₃ /ε ₀ of less than 2000 due to the addition of MnO ₂ , Li ₂ O and/or Fe ₂ O ₃ which have the effect of lowering ε ^T ₃₃ /ε ₀ and increasing the Q _m value. value was shown, and Q _m improved to over 500.

Table 2 below shows the composition of PZT in the form of (1-x)PZT-xPMNN and relaxer with additives in mono- and binary forms, 0.8Pb(Zr _0.475 Ti _0.525 )O ₃ -0.2Pb(Mg _0.5 Ni _0.5 ) _1/3 Nb _2/3 O ₃ + 1.9 at.% MnO ₂ + z at.% Li ₂ O (0.0≤z≤1.8) This is an example with a composition.

[Table 2]

In the case of Example 1, the additive composition satisfied the MnO ₂ primary system, and Q _m showed a significantly higher value compared to Comparative Examples 1 to 5.

In the case of Example 2, it was a binary composition containing MnO ₂ and 1.8 at.% Li ₂ O as additives, and compared to Example 1, the density, d ₃₃ , and k _p showed similar values, while Q _m showed a higher value. indicated.

From this, it can be seen that the piezoelectric material has excellent density and a high Q _m value at low temperature sintering by containing one or more types of additives.

Table 3 below shows a composition containing PZT in the form of (1-x)PZT-xPMNN and a relaxer with additives in a ternary system, 0.8Pb(Zr _0.475 Ti _0.525 )O ₃ -0.2Pb(Mg _0.5 Ni _0.5 ) _{1/ 3} Nb _2/3 O ₃ + 1.9 at.% MnO ₂ + 1.8 at.% Li ₂ O + w at.% Fe ₂ O ₃ (0.4≤w≤2.0) This is an example with a composition.

[Table 3]

Examples 3 to 8 in Table 3 are ternary compositions in which the content of the additive Fe ₂ O ₃ is gradually increased from the composition of Example 2 in Table 2.

Examples 3 to 7 are compared to Example 2, Due to the effect of the additive Fe ₂ O ₃ on improving the mechanical quality factor, higher Q _m values of 1026 to 4152 were exhibited. A similar effect was observed at the additive Fe ₂ O ₃ content of 0.4≤w≤2.0.

On the other hand, when the additive Fe ₂ O ₃ content exceeded 2.0 at.% as in Example 8, k _p and Q _m were lower than the k _{p and} Q _m values of Examples 3 to 7.

From this, the piezoelectric material has an Fe ₂ O ₃ content of 2.0 in the additive composition. It can be seen that as at.% or less is satisfied and the additive composition increases from binary to ternary, the higher the Q _m value.

Table 4 below shows a composition containing PZT in the form of (1-x)PZT-xPMNN and a relaxer with additives in a ternary system, 0.8Pb(Zr _0.475 Ti _0.525 )O ₃ -0.2Pb(Mg _0.5 Ni _0.5 ) _{1/ 3} Nb _2/3 O ₃ in the form of + 1.9 at.% MnO ₂ + 0.9 at.% Li ₂ O + w at.% Fe ₂ O ₃ (0.0≤w≤1.2) This is an example with a composition.

[Table 4]

In the case of Example 9, it is a binary composition containing 1.9 at.% MnO ₂ and 0.9 at.% Li ₂ O as additives.

In Examples 10 to 12, higher Q _m values of 1112 to 4276 were shown compared to Example 9 due to the effect of improving the mechanical quality coefficient by the addition of Fe ₂ O ₃ .

A similar effect was shown at an additive Fe ₂ O ₃ content of 0.4≤w≤1.2.

From this, it can be seen that the piezoelectric material exhibits better hard composition piezoelectric properties as the additive composition increases from binary to ternary.

Table 5 below shows a composition containing PZT in the form of (1-x)PZT-xPMNN and a relaxer with binary to ternary additives, 0.8Pb(Zr _0.475 Ti _0.525 )O ₃ -0.2Pb(Mg _0.5 Ni _0.5 ) _1/3 Nb _2/3 O ₃ + 1.9 at.% MnO ₂ + z at.% Li ₂ O + 0.4 at.% Fe ₂ O ₃ (0.0≤z≤3.5) This is an example with a composition.

[Table 5]

In the case of Example 13, it is a binary composition containing 1.9 at.% MnO ₂ and 0.4 at.% Fe ₂ O ₃ as additives.

In the case of Examples 14 to 16, the composition contained more of the additive Li ₂ O than that of Example 13, and showed equivalent or better effects. A similar effect was shown at an additive Li ₂ O content of 0.9≤z≤3.5.

On the other hand, when the additive Li ₂ O content exceeded 5.0 at.% as in Example 17, k _p and Q _m were lower than the k _{p and} Q _m values of Examples 14 to 16.

Table 6 below shows a composition containing PZT in the form of (1-x)PZT-xPMNN and a relaxer with additives in a ternary system, 0.8Pb(Zr _1-a Ti _a )O ₃ -0.2Pb(Mg _0.5 Ni _0.5 ) _1/3 Nb _2/3 O ₃ + y at.% MnO ₂ + 1.8 at.% Li ₂ O + 0.8 at.% Fe ₂ O ₃ (0.525≤a≤0.530, 1.1≤y≤2.6) This is an example with a composition.

[Table 6]

In Examples 18 to 21, the additive ternary composition showed excellent results in all physical properties, and similar effects were obtained even when the MnO ₂ content was changed to 1.1≤y≤2.6.

Table 7 below shows a composition containing PZT in the form of (1-x)PZT-xPMNN and a relaxer with additives in a ternary system, (1-x)Pb(Zr _0.50 Ti _0.50 )O ₃ -xPb(Mg _0.5 Ni _0.5 ) _1/3 Nb _2/3 O ₃ + 1.9 at.% MnO ₂ + 1.8 at.% Li ₂ O + 0.8 at.% Fe ₂ O ₃ (0.15≤x≤0.25).

[Table 7]

In Examples 22 to 24, excellent hard composition characteristics were shown when the ratio of PZT and relaxer was adjusted to 0.15≤x≤0.25 under conditions including a ternary composition of additives.

Table 8 below shows a composition containing PZT in the form of (1-x)PZT-xPMNN and a relaxer with additives in a ternary system, 0.8Pb(Zr _1-a Ti _a )O ₃ -0.2Pb(Mg _0.5 Ni _0.5 ) This is an example having a composition of _1/3 Nb _2/3 O ₃ + 1.9 at.% MnO ₂ + 1.8 at.% Li ₂ O + 0.8 at.% Fe ₂ O ₃ (0.50≤a≤0.54).

[Table 8]

In Examples 25 to 28, when the ratio of Zr and Ti of PZT was adjusted to 0.50≤a≤0.54 under conditions including a ternary composition of additives, excellent properties were exhibited in all physical properties.

Table 9 below shows a binary composition containing PZT in the form of (1-x)PZT-xPMN and a relaxer with additives. Examples 29 to 31 (1-x)Pb(Zr _0.50 Ti _0.50 )O ₃ -xPb(Mg _1/3 Nb _2/3 )O ₃ + 1.9 at.% MnO ₂ + 1.8 at.% Li ₂ O (0.15≤x≤0.25), and Comparative Examples 6 to 7 are compositions that deviate from the above composition of 0.15≤x≤0.25.

[Table 9]

In Examples 29 to 31, when the ratio of PZT and relaxer was adjusted to 0.15≤x≤0.25 in a binary composition containing MnO ₂ and Li ₂ O as additives, excellent effects were shown in all physical property items.

On the other hand, in Comparative Example 6, because the x value was less than 0.15, the k _p value was less than 0.50, and the Q _m value was very low, less than 100.

In Comparative Example 7, because the x value exceeded 0.25, the k _p value was less than 0.50.

Table 10 below shows a composition containing PZT in the form of (1-x)PZT-xPMN and additives in a relaxer as a binary system, and Examples 30, 32 to 35 are 0.8Pb (Zr _1-a Ti _a )O ₃ - 0.2Pb(Mg _1/3 Nb _2/3 )O ₃ + 1.9 at.% MnO ₂ + 1.8 at.% Li ₂ O (0.50≤a≤0.54) Composition, and Comparative Examples 8 to 9 are compositions that deviate from the above composition by 0.50≤a≤0.54.

[Table 10]

In Examples 30, 32 to 35, when the ratio of Zr and Ti of PZT was adjusted to 0.50≤a≤0.54 in a binary composition containing MnO ₂ and Li ₂ O as additives, excellent effects were shown in all physical property items. It was.

On the other hand, Comparative Example 8 showed a k _p value of less than 0.50 because the a value was less than 0.50.

On the other hand, in Comparative Example 9, because the a value exceeded 0.54, the Q _m value was less than 500.

Table 11 below shows a composition containing PZT in the form of (1-x)PZT-xPMN and a relaxer with a binary additive, 0.8Pb(Zr _0.47 Ti _0.53 )O ₃ -0.2Pb(Mg _1/3 Nb _{2/ 3} )O ₃ + y at.% MnO ₂ + 1.8 at.% Li ₂ O (1.1≤y≤3.7) This is an example with a composition.

[Table 11]

In the case of Examples 34, 36 to 38, it is a binary composition containing MnO ₂ and 1.8 at.% Li ₂ O as additives.

At an additive MnO ₂ content of 1.1 ≤ y ≤ 3.7, similar physical property effects were exhibited, and effects similar to or equivalent to those of the previous examples were exhibited.

On the other hand, when the additive MnO ₂ content exceeded 3.7 at.% as in Example 39, k _p and Q _m were lower than the k _{p and} Q _m values of Examples 34 to 38.

Table 12 below shows a composition containing PZT in the form of (1-x)PZT-xPMN and a relaxer with additives in a ternary system, 0.8Pb(Zr _0.47 Ti _0.53 )O ₃ -0.2Pb(Mg _1/3 Nb _{2/ 3} )O ₃ + 1.9 at.% MnO ₂ + 1.8 at.% Li ₂ O + w at.% Fe ₂ O ₃ (0.4≤w≤1.2) This is an example with a composition.

[Table 12]

In the case of Examples 40 to 42, the composition contained more of the additive Fe ₂ O ₃ compared to Example 33, and showed an equal or better effect.

A similar effect was shown at an additive Fe ₂ O ₃ content of 0.4≤w≤1.2.

Table 13 below shows a composition containing PZT in the form of (1-x)PZT-xPMN and a relaxer with binary to ternary additives, 0.8Pb(Zr _0.47 Ti _0.53 )O ₃ -0.2Pb(Mg _1/3 Nb _2/3 )O ₃ + 1.9 at.% MnO ₂ + 2.6 at.% Li ₂ O + w at.% Fe ₂ O ₃ (0.0≤w≤2.0) This is an example having a composition.

[Table 13]

In the case of Example 43, it was a binary composition containing 1.9 at.% MnO ₂ and 2.6 at.% Li ₂ O as additives, and showed a similar to equivalent effect as Example 34, and the Li ₂ O content was slightly higher. As it increased, compared to Example 34, the sintered density was improved and the mechanical quality factor Q _m was improved.

In Examples 44 to 48, a similar effect was shown at an additive Fe ₂ O ₃ content of 0.4≤w≤2.0.

Table 14 below shows a composition containing PZT in the form of (1-x)PZT-xPMN and a relaxer with additives in a ternary system, 0.8Pb(Zr _0.47 Ti _0.53 )O ₃ -0.2Pb(Mg _1/3 Nb _{2/ 3} )O ₃ + 1.9 at.% MnO ₂ + z at.% Li ₂ O + 0.8 at.% Fe ₂ O ₃ (0.9≤z≤4.4) This is an example having a composition.

[Table 14]

For examples 45, 49 to 52, additive Li ₂ O A similar effect was shown at a content of 0.9≤z≤4.4.

Table 15 below shows a composition containing PZT in the form of (1-x)PZT-xPZN and a relaxer with additives in a binary system, 0.8Pb(Zr _0.5 Ti _0.5 )O ₃ -0.2Pb(Zn _1/3 Nb _{2/ 3} )O ₃ + 1.9 at.% MnO ₂ + 1.8 at.% Li ₂ O This is an example having a composition.

[Table 15]

In the case of Example 53, it is shown that excellent effects are exhibited in all physical property items even if the composition of the relaxer is changed in a composition containing PZT, relaxer, and additives.

Table 16 below shows a composition containing PZT in the form of (1-x)PZT-xPNN and a relaxer with binary to ternary additives, 0.8Pb(Zr _0.5 Ti _0.5 )O ₃ -0.2Pb(Zn _1/3) Nb _2/3 )O ₃ + 1.9 at.% MnO ₂ + 1.8 at.% Li ₂ O + w at.% Fe ₂ O ₃ (0.0≤w≤0.8) This is an example with a composition.

[Table 16]

Example 54 is a composition in which the additive is a binary type, and Example 55 is a composition in which the additive is a ternary type. Looking at the results in Table 16, the Q _m value was further improved when the additive composition was a ternary system compared to a binary system.

Table 17 below shows a composition containing PZT in the form of (1-x)PZT-xPZNN and a relaxer with binary to ternary additives, 0.8Pb(Zr _0.5 Ti _0.5 )O ₃ -0.2Pb[(Zn _0.8 Ni _0.2 ) _1/3 Nb _2/3 ]O ₃ + 1.9 at.% MnO ₂ + 1.8 at.% Li ₂ O + w at.% Fe ₂ O ₃ (0.0≤w≤0.8) This is an example having a composition.

[Table 17]

Example 56 is a composition in which the additive is a binary type, and Example 57 is a composition in which the additive is a ternary type. Looking at the results in Table 17, the Q _m value was further improved when the composition of the additive was ternary rather than binary.

As such, the piezoelectric material of the present invention has the composition (1-x)Pb(Zr _1-a Ti _a )O ₃ - xPb(B ¹ _1/3 Nb _2/3 )O ₃ and MnO ₂ , Li ₂ O and Fe ₂ O By including one or more of the _three additives, low-temperature sintering can be achieved while exhibiting the piezoelectric properties of a hard material, and a cost reduction effect can be expected since low-cost electrodes can be used.

As described above, the present invention has been described with reference to the illustrative embodiments, but the present invention is not limited to the embodiments disclosed herein, and various modifications may be made by those skilled in the art within the scope of the technical idea of the present invention. It is self-evident that this can be achieved. In addition, although the operational effects according to the configuration of the present invention were not explicitly described and explained while explaining the embodiments of the present invention above, it is natural that the predictable effects due to the configuration should also be recognized.

Claims (8)

It has the composition of (1-x)Pb(Zr _1-a Ti _a )O ₃ - xPb(B ¹ _1/3 Nb _2/3 )O ₃ + additives,
The B ¹ is a piezoelectric material containing at least one of Zn, Ni, and Mg.
(However, 0.15 ≤ x ≤ 0.25, 0.50 ≤ a ≤ 0.54.)
According to paragraph 1,
The additive is a piezoelectric material containing one or more of MnO ₂ , Li ₂ O and Fe ₂ O ₃ .
According to paragraph 1,
The additive is a piezoelectric material containing y at% MnO ₂ .
(However, 1.1 ≤ y ≤ 3.7.)
According to paragraph 1,
The additive is a piezoelectric material containing z at% Li ₂ O.
(However, 0 ≤ z ≤ 4.4.)
According to paragraph 1,
The additive is a piezoelectric material containing w at% Fe ₂ O ₃ .
(However, 0 ≤ w ≤ 2.0.)
According to paragraph 1,
When the electromechanical coupling coefficient of the piezoelectric material is k _p , the piezoelectric material is 0.50 ≤ k _p .
According to paragraph 1,
When the mechanical quality factor of the piezoelectric material is Q _m , a piezoelectric material with 500 < Q _m .
A piezoelectric element comprising the piezoelectric material of any one of claims 1 to 7.