JP4510140B2 - Piezoelectric ceramic composition, piezoelectric element and dielectric element - Google Patents

Description

The present invention is a piezoelectric ceramic composition containing no lead in the composition, and to a piezoelectric element and a dielectric element having a piezoelectric ceramic device composition.

Conventionally, PZT (PbTiO ₃ —PbZrO ₃ ) component-based porcelain containing lead has been used as a piezoelectric ceramic composition. This is because the PZT exhibits a large piezoelectricity and has a high mechanical quality factor, and can easily produce materials having various characteristics required for each application such as a sensor, an actuator, and a filter.
Moreover, since the PZT has a high relative dielectric constant, it can also be used as a capacitor.

However, the piezoelectric ceramic composition made of PZT has excellent characteristics, but contains lead as a constituent element, so harmful lead is eluted from industrial waste of products containing PZT, resulting in environmental pollution. There was a risk of causing. The recent increase in awareness of environmental problems has made it difficult to manufacture products that can cause environmental pollution such as PZT. Therefore, development of a piezoelectric ceramic composition containing no lead in the composition is required, and a piezoelectric ceramic composition represented by the general formula (K _1-x Na _x ) NbO ₃ (where 0 <x <1) ( Non-patent document 1) has attracted attention.

However, the piezoelectric ceramic composition represented by the general formula (K _1−x Na _x ) NbO ₃ (where 0 <x <1) has a piezoelectric d ₃₁ constant, an electromechanical coupling coefficient Kp, a piezoelectric g ₃₁ constant, There was a problem that the piezoelectric characteristics such as the mechanical quality factor Qm were low. Therefore, for example, a piezoelectric actuator, a piezoelectric filter, a piezoelectric vibrator, a piezoelectric transformer, a piezoelectric ultrasonic motor, a piezoelectric gyro sensor, a knock sensor, a yaw rate sensor, an airbag sensor, which require a high piezoelectric d ₃₁ constant and an electromechanical coupling coefficient Kp, It was difficult to apply to piezoelectric elements such as back sonar, corner sonar, piezoelectric buzzer, piezoelectric speaker, and piezoelectric igniter.

In addition, the piezoelectric ceramic composition represented by the above general formula has a problem that it is difficult to apply to a dielectric element such as a capacitor because of its low dielectric properties such as relative dielectric constant ε _33T / ε ₀ and dielectric loss tan δ. there were.
“Journal of the American Ceramic Society”, USA, 1962, Vol. 45, no. 5, p. 209

The present invention has been made in view of such conventional problems, and does not contain lead and has high piezoelectric characteristics and dielectric characteristics. In particular, any one of the piezoelectric d ₃₁ constant, the electromechanical coupling coefficient Kp, and the relative dielectric constant can be used. the piezoelectric ceramic composition excellent in one or more or, and is intended to provide a piezoelectric element and a dielectric element using a piezoelectric ceramic device composition.

A first aspect of the present invention is represented by the general formula _{{Li x (K 1-y} Na y) 1-x} a (Nb 1-zw Ta z Sb w) b O 3, and x, y, z, w, a and b are compositions of 0 <x ≦ 0.2, 0.05 ≦ y ≦ 1, 0 <z ≦ 0.4, 0 <w ≦ 0.2, 0.95 ≦ a, b ≦ 1.05, respectively. A piezoelectric ceramic composition mainly composed of a compound in a range,
The piezoelectric ceramic composition contains any one or more metal elements selected from Mg, Ca, Sr, and Ba as additive elements,
The total content of the additive elements is 0.0001 mol to 0.10 mol with respect to 1 mol of the compound represented by the general formula,
The piezoelectric ceramic composition is characterized in that the piezoelectric d ₃₁ constant is 80 pm / V or more and the Curie temperature Tc is 200 ° C. or more (Claim 1).

The second invention are represented by the general formula _{{Li x (K 1-y} Na y) 1-x} a (Nb 1-zw Ta z Sb w) b O 3, and x, y, z, w, a, b are 0 <x ≦ 0.2, 0.05 ≦ y ≦ 1, 0 <z ≦ 0.4, 0 <w ≦ 0.2, 0.95 ≦ a, b ≦ 1.05, respectively. A piezoelectric ceramic composition mainly composed of a compound in the composition range of
The piezoelectric ceramic composition contains any one or more metal elements selected from Si, In, and Sc as an additive element,
The total content of the additive elements is 0.0001 mol or more and 0.08 mol or less with respect to 1 mol of the compound represented by the general formula,
The piezoelectric ceramic composition is characterized in that the piezoelectric d ₃₁ constant is 80 pm / V or more and the Curie temperature Tc is 200 ° C. or more (Claim 3).

A third aspect of the present invention is represented by the general formula _{{Li x (K 1-y} Na y) 1-x} a (Nb 1-zw Ta z Sb w) b O 3, and x, y, z, w, a, b are 0 <x ≦ 0.2, 0.05 ≦ y ≦ 1, 0 <z ≦ 0.4, 0 <w ≦ 0.2, 0.95 ≦ a, b ≦ 1.05, respectively. A piezoelectric ceramic composition mainly composed of a compound in the composition range of
The piezoelectric ceramic composition contains Bi as an additive element,
The content of the additive element is 0.0001 mol to 0.004 mol with respect to 1 mol of the compound represented by the general formula,
A piezoelectric ceramic composition having a piezoelectric d ₃₁ constant of 80 pm / V or more and a Curie temperature Tc of 200 ° C. or more.

Next, the effects of the first to third inventions will be described.
The piezoelectric ceramic compositions of the first to third inventions do not contain lead in the composition.
Therefore, the piezoelectric ceramic composition is safe because harmful lead does not flow out from the waste to the natural world.

The piezoelectric ceramic composition contains the compound represented by the general formula as a main component, and x, y, z, and w in the general formula are in the above ranges, respectively.
Therefore, the piezoelectric ceramic composition, the piezoelectric d ₃₁ constant, electromechanical coupling factor Kp, piezoelectric g ₃₁ constant, piezoelectric properties such as mechanical quality factor Qm, also the relative dielectric constant epsilon _33T / epsilon such ₀ and dielectric loss tanδ Excellent dielectric properties and Curie temperature Tc.
Note that does not contain the additive element, represented by the general formula _{{{Li x (K 1-} y Na y) 1-x} a (Nb 1-zw Ta z Sb w) b O 3 composition Is hereinafter referred to as “basic composition” as appropriate.

In the piezoelectric ceramic composition of the first invention, in addition to the compound having the basic composition represented by the above general formula, any one or more metal elements selected from Mg, Ca, Sr, and Ba are used as additive elements. It is contained within the above range of contents.
The piezoelectric ceramic composition according to the second aspect of the invention includes, in addition to the compound having the basic composition represented by the above general formula, any one or more metal elements selected from Si, In, and Sc as an additive element. It is contained within the above range of contents.
The piezoelectric ceramic composition of the third invention contains Bi in the range of the above content as an additive element in addition to the compound having the basic composition represented by the above general formula.
For this reason, the piezoelectric ceramic composition of the first to third inventions has particularly improved one or more characteristics of the piezoelectric d ₃₁ constant, the electromechanical coupling coefficient Kp, and the relative dielectric constant ε _33T / ε _0. This is even better than a piezoelectric ceramic composition represented by the above general formula, which does not contain the above additive elements.
In the first to third aspects of the invention, the piezoelectric ceramic composition may contain the additive element as a substitute for the compound represented by the general formula. You may make it externally add and contain with respect to the compound represented by a formula.

Thus, the piezoelectric ceramic compositions of the first to third inventions are safe for the environment because they do not contain lead, and have excellent piezoelectric properties, so that they can be used as high-performance piezoelectric elements. can do.
The piezoelectric ceramic composition is also excellent in dielectric properties such as relative permittivity and dielectric loss in addition to the piezoelectric properties. Therefore, the piezoelectric ceramic composition of the first to third inventions can be used as a high-performance dielectric element. That is, the above-mentioned piezoelectric ceramic composition is not limited to a piezoelectric ceramic composition having piezoelectric characteristics, but also includes a dielectric ceramic composition having dielectric characteristics.

According to a fourth aspect of the present invention, there is provided a piezoelectric element comprising the piezoelectric ceramic composition according to the first to third aspects of the invention (claim 10 ).

The piezoelectric element of the fourth invention has a piezoelectric ceramic composition of the first to third inventions. Therefore, the piezoelectric element does not contain lead and is safe for the environment.
Further, the piezoelectric element, the piezoelectric ceramic composition has, can be used as it is characteristic that piezoelectric properties such as piezoelectric d ₃₁ constant is excellent. Therefore, the piezoelectric element includes a highly sensitive piezoelectric sensor element, a piezoelectric actuator having high electromechanical energy conversion efficiency, a piezoelectric filter, a piezoelectric vibrator, a piezoelectric transformer, a piezoelectric ultrasonic motor, a piezoelectric gyro sensor, a knock sensor, a yaw rate sensor, It can be used as a piezoelectric element such as an airbag sensor, a back sonar, a corner sonar, a piezoelectric buzzer, a piezoelectric speaker, and a piezoelectric igniter.

5th invention has the piezoelectric ceramic composition of the said 1st-3rd invention, The dielectric element (Invention 11 ) characterized by the above-mentioned

Dielectric device of the fifth invention has a piezoelectric ceramic composition of the first to third inventions. Therefore, the dielectric element does not contain lead and is safe for the environment.
Further, the dielectric element can utilize the properties of the piezoelectric ceramic composition, which are excellent in relative dielectric constant and dielectric loss. Therefore, it can be used as a capacitor having a large capacitance.

In the present invention, the above general formula _{{Li x (K 1-y} Na y) 1-x} a (Nb 1-zw Ta z Sb w) b O compound represented by _3, x, y, z, w Are in the range of 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, and 0 <w ≦ 0.2, respectively.
Here, when x> 0.2, z> 0.4, w> 0.2, z = 0, or w = 0, the piezoelectric characteristics such as the piezoelectric d ₃₁ constant and the dielectric characteristics deteriorate, and the desired There is a possibility that a piezoelectric ceramic composition having the above characteristics cannot be obtained.
In the general formula _{{Li x (K 1-y} Na y) 1-x} a (Nb 1-zw Ta z Sb w) compound represented by _b O _3, the range of y is, 0 ≦ y ≦ 0.85 is more preferable, and 0.05 ≦ y ≦ 0.75 is more preferable. In these cases, the piezoelectric d ₃₁ constant and electromechanical coupling factor Kp of the piezoelectric ceramic composition can be further improved. Still more preferably, 0.05 ≦ y <0.75 is satisfied, 0.35 ≦ y ≦ 0.65 is further preferable, and 0.35 ≦ y <0.65 is more preferable. Most preferably, 0.42 ≦ y ≦ 0.60.

As described above, the piezoelectric ceramic composition is mainly composed of a compound having a perovskite structure (ABO ₃ ). In the present invention, the elements constituting the A site in the perovskite structure (ABO ₃₎ is, K, Na or corresponds K, Na, a Li, elemental composition of the B site, Nb, Ta, corresponding to Sb. In the composition formula of this perovskite structure, when the stoichiometric ratio of the atoms constituting the A site and the atoms constituting the B site is 1: 1, a complete perovskite structure is obtained. In particular, K, Na, Li, and Sb are volatilized by a few percent, specifically about 3% in the firing process, etc., and all constituent elements are a few percent in the mixed pulverization or granulation process, specifically, May vary by about 3%. In other words, variation from the stoichiometric composition may occur due to manufacturing variations.

  In order to cope with such composition fluctuations in the manufacturing process, by intentionally changing the composition ratio, the composition ratio of the piezoelectric ceramic composition after firing is changed to ± several%, more specifically ± 3 to 5%. % Can be varied. This is the same in the case of conventional zirconate titanate (PZT), for example, and the blending ratio is adjusted in consideration of lead evaporation during firing and zirconia balls mixed from zirconia balls as grinding media. be able to.

In the piezoelectric ceramic composition of the present invention, even if the composition ratio is intentionally changed as described above, electrical characteristics such as piezoelectric characteristics do not change greatly.
Therefore, in the present invention, the compound represented by the above general formula {Li _x (K _{1 -y} Na _y ) _{1 -x} } _a (Nb _{1 -zw} Ta _z Sb _w ) _b O ₃ has a perovskite structure. When the composition formula ABO ₃ is applied, the composition ratio of the A site atom and the B site atom can be shifted to about ± 5 mol% with respect to 1: 1. In order to reduce the number of lattice defects in the formed crystal and obtain high electrical characteristics, the composition is preferably up to about ± 3%.
That is, the compound represented by the above general formula as the main component of the piezoelectric ceramic composition is {Li _x (K _1−y Na _y ) _1−x } _a (Nb _1−zw Ta _z Sb _w ) _b O _{3 (0 ≦ x ≦ 0.2,0 ≦} y ≦ 1,0 <z ≦ 0.4,0 <w ≦ 0.2,0.95 ≦ a, b ≦ 1.05) is intended to include scope . As described above, in the above formula, the ranges of a and b are preferably 0.97 ≦ a and b ≦ 1.03.

Also that the scope of x in the above general formula _{{Li x (K 1-y} Na y) 1-x} a (Nb 1-zw Ta z Sb w) b O 3 is 0 <x ≦ 0.2 Is preferred.
In this case, since Li is an essential component, the piezoelectric ceramic composition can be fired more easily during its production, further improves the piezoelectric characteristics, and further increases the Curie temperature Tc. Can do. This is because by making Li an essential component within the above range, the firing temperature is lowered, and Li serves as a firing aid and enables firing with fewer voids.

The value of x in the general formula _{{Li x (K 1-y} Na y) 1-x} a (Nb 1-zw Ta z Sb w) b O 3 can be the x = 0.
In this case, the general formula is represented by _{(K 1-y Na y)} a (Nb 1-zw Ta z Sb w) b O 3.
In this case, when producing the piezoelectric ceramic composition, since the raw material does not include a compound containing the lightest Li, such as LiCO ₃ , the raw materials are mixed and the piezoelectric ceramic is mixed. When producing the composition, variation in characteristics due to segregation of the raw material powder can be reduced. In this case, a high relative dielectric constant and a relatively large piezoelectric g constant can be realized.

  In the first invention (invention 1), the piezoelectric ceramic composition contains any one or more metal elements selected from Mg, Ca, Sr, and Ba as an additive element. The total content of elements is 0.0001 mol to 0.10 mol with respect to 1 mol of the compound represented by the above general formula. The piezoelectric ceramic composition may contain the additive element as a substitute for the compound represented by the general formula, or may be added to the compound represented by the general formula. May be contained.

When the total content of the additive elements is less than 0.0001 mol or exceeds 0.10 mol, the piezoelectric d ₃₁ constant, the electromechanical coupling coefficient Kp, the relative dielectric constant ε _33T / There is a possibility that ε _{0 and the} like are lowered, and a piezoelectric ceramic composition having desired piezoelectric characteristics and dielectric characteristics cannot be obtained.
Note that the content of the additive element is the number of moles of each metal element of Mg, Ca, Sr, and Ba.

Also, the additional element of the general formula _{{Li x (K 1-y} Na y) 1-x} a (Nb 1-zw Ta z Sb w) b O 3 compound represented by Li, K, Na It is possible to take a form in which at least a part of is replaced with one or more metal elements selected from Mg, Ca, Sr, and Ba. The atoms that can be +2 valent such as Mg, Ca, Sr, and Ba are likely to be arranged by substituting at least part of Li, K, and Na of the compound represented by the above general formula.
On the other hand, the additive element may take the form of the metal element or an oxide containing the element or a compound such as a perovskite structure compound in the grain or boundary of the piezoelectric ceramic composition.

Preferably, the additive element is contained by substituting at least a part of Li, K, and Na of the compound represented by the general formula (claim 2).
In this case, the piezoelectric characteristics such as the piezoelectric d ₃₁ constant and the electromechanical coupling coefficient Kp of the piezoelectric ceramic composition, and the dielectric characteristics such as the relative dielectric constant ε _33T / ε ₀ can be further improved.

Particularly preferably, one or more metal elements selected from Mg, Ca, Sr, and Ba as the additive element are substituted with at least part of K or / and Na of the compound represented by the above general formula, the piezoelectric ceramic composition has the general formula _{{Li x (K 1-y} Na y) 1-x-2u Ma u} a (Nb 1-zw Ta z Sb w) b O 3 ( where, Ma is Mg, Ca , Sr, Ba are one or more metal elements, and x, y, z, w, u are 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, 0, respectively. <W ≦ 0.2, 0.0005 ≦ u ≦ 0.1).
In this case, the piezoelectric characteristics such as the piezoelectric d ₃₁ constant and the electromechanical coupling coefficient Kp of the piezoelectric ceramic composition, and the dielectric characteristics such as the relative dielectric constant ε _33T / ε ₀ can be further improved.

  In the second invention (invention 3), the piezoelectric ceramic composition contains any one or more metal elements selected from Si, In, and Sc as an additive element. The total content is 0.08 mol or less with respect to 1 mol of the compound represented by the above general formula. The piezoelectric ceramic composition may contain the additive element as a substitute for the compound represented by the general formula, or may be added to the compound represented by the general formula. May be contained.

When the total content of the additive elements exceeds 0.08 mol, the piezoelectric characteristics such as the piezoelectric d ₃₁ constant and the electromechanical coupling coefficient Kp of the piezoelectric ceramic composition, and the relative dielectric constant ε _33T / ε ₀ Therefore, there is a possibility that a piezoelectric ceramic composition having desired piezoelectric characteristics and dielectric characteristics cannot be obtained.
Further, the total content of the additive elements is preferably 0.0001 mol or more with respect to 1 mol of the compound represented by the general formula .
In this case, the effect of the additive element can be sufficiently obtained.
Note that the content of the additive element is the number of moles of each metal element of Si, In, and Sc.

Furthermore, the additive elements, Nb in the formula _{{Li x (K 1-y} Na y) 1-x} a (Nb 1-zw Ta z Sb w) b O 3 compound represented by, Ta, Sb It is possible to take a form in which at least a part of is replaced with one or more metal elements selected from Si, In, and Sc. Metal elements that can be +3 or +4, such as Si, In, and Sc, are easily replaced with at least a part of Nb, Ta, and Sb of the compound represented by the above general formula.

On the other hand, the additive element may take the form of the metal element or an oxide containing the element or a compound such as a perovskite structure compound in the grain or boundary of the piezoelectric ceramic composition. That is, the piezoelectric ceramic composition may contain the additive element as a substitute for the compound represented by the general formula. It may be added and contained.
The piezoelectric ceramic composition according to the second aspect of the present invention can exhibit excellent piezoelectric characteristics and dielectric characteristics in any of the two forms described above, regardless of which form contains the additive element. .

In the third invention (invention 4 ), the piezoelectric ceramic composition contains Bi as an additive element, and the content of the additive element is 1 mol of the compound represented by the general formula. And 0.0001 mol to 0.004 mol.

In the above-described third piezoelectric ceramic composition of the present invention, by containing a small amount of Bi of 0.0001Mol～0.004Mol, properties such as piezoelectric d ₃₁ constant is improved.
When the total content is less than 0.0001 or more than _{0.004 mol} , the piezoelectric d ₃₁ constant, the electromechanical coupling coefficient Kp, and the relative dielectric constant ε _33T / ε _{0 of the} piezoelectric ceramic composition. The piezoelectric ceramic composition having desired piezoelectric characteristics and dielectric characteristics may not be obtained.
Note that the content of the additive element is the number of moles of the metal element Bi.

Furthermore, the additive elements, Nb in the formula _{{Li x (K 1-y} Na y) 1-x} a (Nb 1-zw Ta z Sb w) b O 3 compound represented by, Ta, Sb It is possible to take a form in which at least a part of is substituted with Bi atoms. A metal element that can be trivalent, such as Bi, is easily replaced with at least a part of Nb, Ta, and Sb of the compound represented by the above general formula.
On the other hand, the additive element may be in the form of a Bi atom or a compound such as an oxide or a perovskite structure compound that exists in the grain or boundary of the piezoelectric ceramic composition. That is, the piezoelectric ceramic composition may contain the additive element as a substitute for the compound represented by the general formula. It may be added and contained.
The piezoelectric ceramic composition according to the third aspect of the present invention can exhibit excellent piezoelectric characteristics and dielectric characteristics in the same manner regardless of which of the two forms described above contains the additive element. .

Next, in the first to third inventions, the piezoelectric d ₃₁ constant of the piezoelectric ceramic composition is represented by the above general formula, and is greater than the piezoelectric d 31 constant of the piezoelectric ceramic composition not containing the additive element. , Larger is preferable .

The above-mentioned “larger than the piezoelectric d ₃₁ constant of the piezoelectric ceramic composition represented by the above general formula and not containing the additive element” means that the piezoelectric d ₃₁ constant of the piezoelectric ceramic composition containing the additive element is This means that it is larger than a piezoelectric ceramic composition having the basic composition of this piezoelectric ceramic composition and not containing the above additive elements (hereinafter referred to as a basic piezoelectric ceramic composition as appropriate). The same applies to the mechanical coupling coefficient Kp, the piezoelectric g ₃₁ constant, the mechanical quality coefficient Qm, the relative permittivity, the dielectric loss, and the Curie temperature Tc.

Further, the electromechanical coupling coefficient Kp of the piezoelectric ceramic composition is represented by the above general formula, and is preferably larger than the electromechanical coupling coefficient Kp of the piezoelectric ceramic composition not containing the additive element .

The piezoelectric g ₃₁ constant of the piezoelectric ceramic composition is represented by the above general formula, and is preferably larger than the piezoelectric g ₃₁ constant of the piezoelectric ceramic composition not containing the additive element .

Furthermore, the mechanical quality factor Qm of the piezoelectric ceramic composition is expressed by the above general formula, and is preferably larger than the mechanical quality factor Qm of the piezoelectric ceramic composition not containing the additive element .

The piezoelectric d ₃₁ constant, the electromechanical coupling coefficient Kp, the piezoelectric g ₃₁ constant, and the mechanical quality factor Qm of the piezoelectric ceramic composition are represented by the above general formula, and the basic piezoelectric ceramic composition containing no additive element is used. If it is larger than the above, the effect of the additive element can be sufficiently obtained. Piezoelectric actuator, piezoelectric filter, piezoelectric vibrator, piezoelectric transformer, piezoelectric ultrasonic motor, piezoelectric gyro sensor, knock sensor, yaw rate sensor, air Application to piezoelectric elements such as bag sensors, back sonars, corner sonars, piezoelectric buzzers, piezoelectric speakers, and piezoelectric igniters becomes easier.

Next, the relative dielectric constant of the piezoelectric ceramic composition is represented by the above general formula and is preferably larger than the relative dielectric constant of the piezoelectric ceramic composition not containing the additive element .
If the dielectric constant of the piezoelectric ceramic composition (basic piezoelectric ceramic composition) which is represented by the above general formula and does not contain the additive element is smaller than that, the effect of the additive element cannot be sufficiently obtained. In addition, application to a dielectric element such as a capacitor may be difficult.

Next, the dielectric loss of the piezoelectric ceramic composition is represented by the above general formula, and is preferably smaller than the dielectric loss of the piezoelectric ceramic composition not containing the additive element .
If the dielectric loss of the piezoelectric ceramic composition (basic piezoelectric ceramic composition) that is expressed by the above general formula and does not contain the additive element is larger than that, the effect of the additive element cannot be sufficiently obtained. Therefore, it may be difficult to apply to a dielectric element such as a capacitor.

Next, the Curie temperature Tc of the piezoelectric ceramic composition is represented by the above general formula and is preferably larger than the Curie temperature Tc of the piezoelectric ceramic composition not containing the additive element .
When the temperature is higher than the Curie temperature of the piezoelectric ceramic composition (basic piezoelectric ceramic composition) which is represented by the above general formula and does not contain the additive element, the effect of the additive element can be sufficiently obtained. Use in a high temperature environment exceeding 100 ° C. such as the vicinity of an automobile engine becomes easier.

Next, the piezoelectric ceramic composition preferably has a piezoelectric d ₃₁ constant of 30 pm / V or more .
In this case, taking advantage of the high piezoelectric d ₃₁ constant of 30 pm / V or more, the piezoelectric ceramic composition can be used as a piezoelectric actuator, piezoelectric filter, piezoelectric vibrator, piezoelectric transformer, piezoelectric ultrasonic motor, piezoelectric gyro sensor, knock sensor. , Yaw rate sensor, airbag sensor, back sonar, corner sonar, piezoelectric buzzer, piezoelectric speaker, piezoelectric igniter and the like.
Above for the piezoelectric d ₃₁ constant is less than 30 Pm/V, it may not be used as a piezoelectric element sufficiently endure characteristics for practical use.

In order to obtain a piezoelectric sensor characteristic with higher sensitivity or a larger piezoelectric actuator characteristic, the piezoelectric d ₃₁ constant is more preferably 40 pm / V or more. More preferably, it is 80 pm / V or more. Even more preferably, it is 100 pm / V or more.

Next, the piezoelectric ceramic composition is preferably electro-mechanical coupling coefficient Kp is 0.30 or more (claim 5).
In this case, utilizing the high electromechanical coupling coefficient Kp of 0.30 or more, the piezoelectric ceramic composition can be converted into a piezoelectric actuator, a piezoelectric filter, a piezoelectric vibrator, a piezoelectric transformer, excellent in conversion efficiency between mechanical energy and electrical energy, It can be used as a piezoelectric ultrasonic motor, piezoelectric gyro sensor, knock sensor, yaw rate sensor, airbag sensor, back sonar, corner sonar, piezoelectric buzzer, piezoelectric speaker, piezoelectric igniter and the like.

When the electromechanical coupling coefficient Kp is less than 0.30, the piezoelectric ceramic composition may not be used for a piezoelectric element that requires excellent conversion efficiency between the mechanical energy and the electrical energy. .
Further, in order to obtain a further excellent conversion efficiency between mechanical energy and electrical energy, the electromechanical coupling coefficient Kp is more preferably 0.34 or more. More preferably, 0.4 or more is good. Still more preferably, 0.45 or more is good.

Next, the piezoelectric ceramic composition preferably has a piezoelectric g ₃₁ constant of 7 × 10 ⁻³ Vm / N or more (claim 6 ).
In this case, the piezoelectric ceramic composition is used as a piezoelectric transformer, an ultrasonic motor element, a sensor element or the like having an excellent step-up ratio by utilizing the high piezoelectric g ₃₁ constant of 7 × 10 ⁻³ Vm / N or more. be able to.

Above for piezoelectric g ₃₁ constant of less than 7 × 10 ^-3 Vm / N, it may not be available to the piezoelectric element which requires an excellent boost ratio the piezoelectric ceramic composition.
In order to obtain a further excellent boost ratio, the piezoelectric g ₃₁ constant is more preferably 8 × 10 ⁻³ Vm / N or more.

Next, the piezoelectric ceramic composition, the mechanical quality factor Qm is is preferably 50 or more (claim 7).
In this case, utilizing the high mechanical quality factor Qm of 50 or more, the piezoelectric ceramic composition can be used to produce a piezoelectric element with little heat generation and excellent conversion efficiency between electric energy and mechanical energy, such as a piezoelectric actuator, a piezoelectric filter, It can be used as a piezoelectric vibrator, piezoelectric transformer, piezoelectric ultrasonic motor, piezoelectric gyro sensor, knock sensor, yaw rate sensor, airbag sensor, back sonar, corner sonar, piezoelectric buzzer, piezoelectric speaker, piezoelectric igniter and the like.

When the mechanical quality factor Qm is less than 50, the piezoelectric ceramic composition may not be used for a piezoelectric element that requires excellent conversion efficiency of the mechanical energy and electrical energy.
Further, in order to obtain a further excellent conversion efficiency between mechanical energy and electric energy, the mechanical quality factor Qm is more preferably 40 or more. More preferably, 50 or more is good.

Next, the piezoelectric ceramic composition preferably has a specific dielectric constant of 400 or more (claim 8).
In this case, the piezoelectric ceramic composition can be used as a dielectric element such as a capacitor having a large electrostatic capacity by utilizing a high relative dielectric constant of 400 or more.

When the relative dielectric constant is less than 400, the capacitance decreases, and the piezoelectric ceramic composition may not be used as a dielectric element such as a capacitor.
The relative dielectric constant is preferably 430 or more. More preferably, 600 or more is good.

Next, the piezoelectric ceramic composition is preferably a dielectric loss is 0.09 or less (claim 9).
In this case, taking advantage of the low dielectric loss of 0.09 or less, the piezoelectric ceramic composition is used as a dielectric element such as a capacitor, piezoelectric actuator, piezoelectric filter, piezoelectric vibrator, piezoelectric transformer, piezoelectric ultrasonic motor, piezoelectric gyro sensor. , Knock sensor, yaw rate sensor, airbag sensor, back sonar, corner sonar, piezoelectric buzzer, piezoelectric speaker, piezoelectric igniter and the like.

  When the dielectric loss exceeds 0.09, the piezoelectric ceramic composition may not be used as a dielectric element such as a capacitor, a piezoelectric transformer element, an ultrasonic motor element or the like. Therefore, more preferably, the dielectric loss is 0.035 or less. More preferably, 0.03 or less is good.

Next, the piezoelectric ceramic composition preferably has a Curie temperature Tc of 200 ° C. or higher .
In this case, utilizing the high Curie temperature Tc of 200 ° C. or higher, the piezoelectric ceramic composition can be used in a high temperature environment exceeding 100 ° C., for example, in the vicinity of an automobile engine.
When the Curie temperature Tc is lower than 200 ° C., the piezoelectric ceramic composition is used in a high temperature place such as the vicinity of an automobile engine, and the characteristics such as the piezoelectric d31 constant and the electromechanical coupling coefficient Kp are lowered. There is a fear. Therefore, more preferably, the Curie temperature Tc is preferably 250 ° C. or higher.

Next, the piezoelectric ceramic composition preferably has a piezoelectric d ₃₁ constant of 30 pm / V or higher and a Curie temperature Tc of 200 ° C. or higher .
In this case, the piezoelectric ceramic composition can be used as a highly sensitive sensor element, ultrasonic motor element, actuator element, piezoelectric transformer element, piezoelectric vibrator, etc. in a high temperature environment exceeding 100 ° C. .
In order to obtain more sensitive piezoelectric sensor characteristics or greater piezoelectric actuator characteristics, the piezoelectric d ₃₁ constant is preferably 40 pm / V or more. More preferably, it is 80 pm / V or more. Even more preferably, the piezoelectric d ₃₁ constant is 100 pm / V or more.
The Curie temperature Tc is more preferably 250 ° C. or higher .

Next, the piezoelectric ceramic composition preferably has a piezoelectric g ₃₁ constant of 7 × 10 ⁻³ Vm / N or higher and a Curie temperature Tc of 200 ° C. or higher .
In this case, the piezoelectric ceramic composition can be used as a piezoelectric transformer, an ultrasonic motor element, a sensor element or the like having an excellent step-up ratio in a high temperature environment exceeding 100 ° C.
In order to obtain a further excellent boost ratio, the piezoelectric g ₃₁ constant is more preferably 8 × 10 ⁻³ Vm / N or more.
The Curie temperature Tc is more preferably 250 ° C. or higher.

Next, the piezoelectric ceramic composition preferably has an electromechanical coupling coefficient Kp of 0.3 or more and a Curie temperature Tc of 200 ° C. or more .
In this case, the piezoelectric ceramic composition is excellent in the conversion efficiency of mechanical energy and electrical energy in a high temperature environment exceeding 100 ° C., piezoelectric actuator element, piezoelectric vibrator, sensor element, piezoelectric transformer element, ultrasonic wave It can be used as a motor element or the like.
Further, in order to obtain a further excellent conversion efficiency between mechanical energy and electrical energy, the electromechanical coupling coefficient Kp is more preferably 0.34 or more. More preferably, 0.4 or more is good.
The Curie temperature Tc is more preferably 250 ° C. or higher.

Next, the piezoelectric ceramic composition preferably has a mechanical quality factor Qm of 50 or more and a Curie temperature Tc of 200 ° C. or more .
In this case, in a high temperature environment exceeding 100 ° C., the piezoelectric ceramic composition is a piezoelectric element that generates little heat and is excellent in conversion efficiency between mechanical energy and electrical energy, such as a piezoelectric actuator, a piezoelectric filter, and a piezoelectric vibrator. , Piezoelectric transformer, piezoelectric ultrasonic motor, piezoelectric gyro sensor, knock sensor, yaw rate sensor, airbag sensor, back sonar, corner sonar, piezoelectric buzzer, piezoelectric speaker, piezoelectric igniter, and the like.
Further, in order to obtain a further excellent conversion efficiency between mechanical energy and electric energy, the mechanical quality factor Qm is more preferably 40 or more. More preferably, 50 or more is good.
The Curie temperature Tc is more preferably 250 ° C. or higher.

Next, the piezoelectric ceramic composition preferably has a dielectric loss of 0.09 or less and a Curie temperature Tc of 200 ° C. or more .
In this case, the piezoelectric ceramic composition can be used as a dielectric element such as a capacitor, a piezoelectric transformer element, an ultrasonic motor element, a sensor element or the like in a high temperature environment exceeding 100 ° C.
The dielectric loss is more preferably 0.035 or less. More preferably, 0.03 or less is good.
The Curie temperature Tc is more preferably 250 ° C. or higher.

Next, the piezoelectric ceramic composition preferably has a piezoelectric d ₃₁ constant of 30 pm / V or more, an electromechanical coupling coefficient Kp of 0.3 or more, and a Curie temperature Tc of 200 ° C. or more .
In this case, the piezoelectric ceramic composition can be used in a high temperature environment exceeding 100 ° C., and can be excellent in sensitivity and conversion efficiency between mechanical energy and electric energy.
In order to obtain more sensitive piezoelectric sensor characteristics or greater piezoelectric actuator characteristics, the piezoelectric d ₃₁ constant is more preferably 40 pm / V or more. The electromechanical coupling coefficient Kp is more preferably 0.34 or more.

The piezoelectric ceramic composition of the first invention is represented by, for example, the general formula _{{Li x (K 1-y} Na y) 1-x} a (Nb 1-zw Ta z Sb w) b O 3, X, y, z, w, a and b are 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, 0 <w ≦ 0.2, 0.95 ≦ a, respectively. The amount of the metal element with respect to 1 mol of the compound represented by the general formula, a compound having a composition range of b ≦ 1.05 and an additive containing one or more metal elements selected from Mg, Ca, Sr, and Ba Can be produced by mixing and baking so that the amount of the solution becomes 0.0001 mol to 0.10 mol.
The piezoelectric ceramic composition according to the first invention includes, for example, a compound containing Li, a compound containing Na, a compound containing K, a compound containing Nb, a compound containing Ta, a compound containing Sb, expressed in after firing the general formula _{{Li x (K 1-y} Na y) 1-x} a (Nb 1-zw Ta z Sb w) b O 3, and x, y, z, w, a, and b are 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, 0 <w ≦ 0.2, 0.95 ≦ a, and b ≦ 1.05, respectively. Prepared in a stoichiometric ratio so as to become a compound in the composition range of the above, or in a stoichiometric ratio considering substitution with a metal element contained in the following additives, and further Mg, Ca, Sr, Ba An additive containing any one or more metal elements selected from the group consisting of the above metal element amount of 0.1 mol of the compound represented by the above general formula is 0. It was mixed so that 001Mol～0.10Mol, can be produced by firing.
Examples of the additive include one or more metal elements selected from Mg, Ca, Sr, and Ba, and compounds containing these metal elements.
The additive has the general formula {Li _x (K _1−y Na _y ) _1−x } _a (Nb _1−zw Ta _z Sb _w ) after the firing, using the metal element contained in the additive as an additive element. _b It may be contained in the piezoelectric ceramic composition by substituting at least part of Li, K, and Na of the compound represented by O ₃ .
In some cases, the metal element or an oxide containing the metal element or a compound such as a perovskite structure compound may be contained in the grain or grain boundary in the piezoelectric ceramic composition.

The piezoelectric ceramic composition of the second invention are represented by, for example, the general formula _{{Li x (K 1-y} Na y) 1-x} a (Nb 1-zw Ta z Sb w) b O 3, A compound in which x, y, z, and w are in a composition range of 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, and 0 <w ≦ 0.2, and Si, In And an additive containing one or more metal elements selected from Sc so that the amount of the metal element with respect to 1 mol of the compound represented by the general formula is 0.0001 mol or more and 0.08 mol or less, It can be manufactured by firing.
Further, the piezoelectric ceramic composition of the second invention includes, for example, a compound containing Li, a compound containing Na, a compound containing K, a compound containing Nb, a compound containing Ta, a compound containing Sb, expressed in after firing the general formula _{{Li x (K 1-y} Na y) 1-x} a (Nb 1-zw Ta z Sb w) b O 3, and x, y, At a stoichiometric ratio such that z and w are compounds in the composition ranges of 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, and 0 <w ≦ 0.2, respectively. Or a stoichiometric ratio considering substitution with a metal element contained in the following additive, and an additive containing any one or more metal elements selected from Si, In, and Sc The amount of the metal element with respect to 1 mol of the compound represented by the formula is 0.0001 mol or more and 0.08 mol or less. Were mixed so that can be produced by firing.
Examples of the additive include one or more metal elements selected from Si, In, and Sc, and compounds containing these metal elements.
The additive has the general formula {Li _x (K _1−y Na _y ) _1−x } _a (Nb _1−zw Ta _z Sb _w ) after the firing, using the metal element contained in the additive as an additive element. _{b In} some cases, it is substituted into at least a part of Nb, Ta, and Sb of the compound represented by O ₃ and is contained in the piezoelectric ceramic composition. In some cases, the metal element or an oxide containing the metal element or a compound such as a perovskite structure compound may be contained in the grain or grain boundary in the piezoelectric ceramic composition.

The piezoelectric ceramic composition of the third invention is represented by, for example, the general formula _{{Li x (K 1-y} Na y) 1-x} a (Nb 1-zw Ta z Sb w) b O 3, and x , Y, z, w, a, b are 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, 0 <w ≦ 0.2, 0.95 ≦ a, b ≦, respectively. Mixing and baking a compound having a composition range of 1.05 and an additive containing Bi such that the Bi amount is 0.0001 mol to 0.004 mol or less with respect to 1 mol of the compound represented by the above general formula. Can be manufactured.
The piezoelectric ceramic composition according to the third aspect of the invention includes, for example, a compound containing Li, a compound containing Na, a compound containing K, a compound containing Nb, a compound containing Ta, a compound containing Sb, expressed in after firing the general formula _{{Li x (K 1-y} Na y) 1-x} a (Nb 1-zw Ta z Sb w) b O 3, and x, y, z, w, a, and b are 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, 0 <w ≦ 0.2, 0.95 ≦ a, and b ≦ 1.05, respectively. Prepared at a stoichiometric ratio so as to be a compound in the composition range of the above, or at a stoichiometric ratio considering substitution with Bi atoms contained in the following additive, and further containing Bi Mix and fire so that the Bi amount per mole of the compound represented by the general formula is 0.0001 mol to 0.004 mol or less. It can be produced by the.
Examples of the additive include Bi atoms or compounds containing Bi atoms.
The additive has the general formula {Li _x (K _{1 -y} Na _y ) _1-x } _a (Nb _{1 -zw} Ta _z Sb _w ) after the firing, using Bi contained in the additive as an additive element. _{b In} some cases, it is substituted into at least a part of Nb, Ta, and Sb of the compound represented by O ₃ and is contained in the piezoelectric ceramic composition. In some cases, the Bi atom or a compound containing a Bi atom or a compound such as a perovskite structure compound is contained in a grain or a grain boundary in the piezoelectric ceramic composition.

A compound containing Li, a compound containing Na, a compound containing K, a compound containing Nb, a compound containing Ta, a compound containing Sb, and the additive are added to the compound. When mixed in a stoichiometric ratio considering substitution with metal elements or Bi atoms contained in the product, Li, Na, K, Nb, Ta, and Sb in the compound represented by the above general formula At least a part of any one or more kinds can be positively replaced with the metal element or Bi atom contained in the additive.
"Prepared with stoichiometric ratio considering substitution by metal element contained in additive", and "Prepared with stoichiometric ratio considering substitution by Bi atom contained in additive" For example, when substituting the metal element or Bi atom of the additive for Li in the compound represented by the above general formula, the amount of the compound containing Li is reduced, and the additive is added by the reduced amount. with mixing Te, as a whole, the compound represented by the general formula _{{Li x (K 1-y} Na y) 1-x} a (Nb 1-zw Ta z Sb w) b O 3 is synthesized after firing This can be achieved by preparing with a stoichiometric ratio.
In the above general formula, in the case of substituting with other atoms such as K, Na, Nb, Ta, and Sb, the amount of the compound containing these is reduced, and the additive containing the metal element or Bi atom to be replaced by that amount is added. It can be realized by addition or the like.
On the other hand, after or before calcination calcination, the general formula _{{Li x (K 1-y} Na y) 1-x} a (Nb 1-zw Ta z Sb w) b O 3 in such that a compound represented And a compound containing Li, a compound containing Na, a compound containing K, a compound containing Nb, a compound containing Ta, and a compound containing Sb at various stoichiometric ratios. The piezoelectric ceramic composition containing the additive as a compound such as the metal element, Bi, or an oxide or a perovskite structure compound containing the metal element, Bi, or the like is actively produced by preparing and further mixing the additive. can do.
Examples of the lithium-containing compound include Li ₂ CO ₃ , Li ₂ O, LiNO ₃ , and LiOH. Examples of the compound containing sodium include Na ₂ CO ₃ , NaHCO ₃ , and NaNO ₃ .

The compounds containing potassium include K ₂ CO ₃ , KNO ₃ , KNbO ₃ , KTaO _{3 and the} like. Examples of the compound containing niobium include Nb ₂ O ₅ , Nb ₂ O ₃ , and NbO ₂ . Examples of the compound containing tantalum include Ta ₂ O ₅ . Examples of the antimony-containing compound include Sb ₂ O ₅ , Sb ₂ O ₃ , and Sb ₂ O ₄ .

Next, in producing the piezoelectric ceramic composition of the first invention, the Li-containing compound is Li ₂ CO ₃ , the Na-containing compound is Na ₂ CO ₃ , and the K-containing compound is K ₂ CO ₃ , the compound containing Nb is Nb ₂ O ₅ , the compound containing Ta is Ta ₂ O ₅ , the compound containing Sb is Sb ₂ O ₅ or Sb ₂ O ₃ , and the additive is It is preferably at least one selected from MgO, MgCO ₃ , CaO, CaCO ₃ , SrO, SrCO ₃ , BaO, and BaCO ₃ .
In this case, the piezoelectric ceramic composition of the first invention can be easily produced.

In producing the piezoelectric ceramic composition of the second invention, the Li-containing compound is Li ₂ CO ₃ , the Na-containing compound is Na ₂ CO ₃ , and the K-containing compound is K ₂ CO ₃ , the compound containing Nb is Nb ₂ O ₅ , the compound containing Ta is Ta ₂ O ₅ , the compound containing Sb is Sb ₂ O ₅ or Sb ₂ O ₃ , and the additive is SiO Preferably, it is at least one selected from ₂ , In ₂ O ₃ , and Sc ₂ O ₃ .
In this case, the piezoelectric ceramic composition of the second invention can be easily produced.

In producing the piezoelectric ceramic composition of the third invention, the Li-containing compound is Li ₂ CO ₃ , the Na-containing compound is Na ₂ CO ₃ , and the K-containing compound is K ₂ CO ₃ , the compound containing Nb is Nb ₂ O ₅ , the compound containing Ta is Ta ₂ O ₅ , the compound containing Sb is Sb ₂ O ₅ or Sb ₂ O ₃ , and the additive is Bi ₂ O ₃ is preferred .
In this case, the piezoelectric ceramic composition of the third invention can be easily produced.

Then, in the above-described fourth invention (claim 10), as the piezoelectric element, for example a piezoelectric actuator, a piezoelectric filter, a piezoelectric vibrator, a piezoelectric transformer, piezoelectric ultrasonic motor, a piezoelectric gyro sensors, knock sensors, yaw rate sensor, There are airbag sensors, back sonar, corner sonar, piezoelectric buzzer, piezoelectric speaker, piezoelectric igniter and so on.

Next, in the fifth aspect (invention 11 ), examples of the dielectric element include a capacitor and a multilayer capacitor.

Example 1
Next, the piezoelectric ceramic composition according to the example of the present invention will be described.
In this example, the piezoelectric ceramic composition of the first invention (invention 1) is manufactured and its characteristics are measured.
The piezoelectric ceramic composition of this example is represented by the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3, and x, y, z, w Are piezoelectric ceramic compositions mainly composed of compounds in the composition ranges of 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, and 0 <w ≦ 0.2. The piezoelectric ceramic composition contains any one or more metal elements selected from Mg, Ca, Sr, and Ba as additive elements. And the sum total of content of the said additional element is 0.01 mol with respect to 1 mol of compounds represented by the said general formula.

The method for producing a piezoelectric ceramic composition of this example includes a compound containing Li, a compound containing Na, a compound containing K, a compound containing Nb, a compound containing Ta, and Sb. with a compound of the general formula after calcination _{{Li x (K 1-y} Na y) 1-x} is represented by _{(Nb 1-zw Ta z Sb} w) O 3, and x, y, z, w, respectively Prepared in a stoichiometric ratio such that the compound is in the composition range of 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, 0 <w ≦ 0.2, and Mg , Ca, Sr, Ba, and an additive containing one or more metal elements selected from the group consisting of Ca, Sr, and Ba are mixed and fired.

Hereinafter, the manufacturing method of the piezoelectric ceramic composition of this example will be described in detail.
First, as a raw material of the basic composition of the piezoelectric ceramic composition, high purity Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , Sb ₂ O ₅ having a purity of 99% or more. , And CaO, SrO, MgO, and BaO as the additives were prepared.

Among these _{materials, Li 2 CO 3, Na 2} CO 3, K 2 CO 3, Nb 2 O 5, Ta 2 O 5, the Sb ₂ O _5, the general formula after firing {Li _x (K _1-y Na _y ) _1−x } (Nb _1−zw Ta _z Sb _w ) O ₃ , x, y, z, w are x = 0.04, y = 0.5, z = 0.1, w = The stoichiometric ratio is _0.04 , that is, the stoichiometric ratio is such that the above general formula is {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O _3. Further, CaO, SrO, MgO, or BaO as the above additives were blended to obtain eight kinds of blends.

The compounding amount of the additive, the stoichiometric compound is expected to be obtained after firing by blending at ratio _{{Li 0.04 (K 0.5 Na 0.5} ) 0.96} (Nb 0.86 Ta 0.1 Sb 0.04) O 3 1mol In contrast, 0.01 mol and 0.005 mol of CaO, SrO, MgO, or BaO as the above-mentioned additives were blended, respectively. At this time, the compounding amount of the metal element of each additive is also 0.01 mol and 0.005 mol.
In addition, among the above-mentioned additives, CaO was further prepared by blending 0.02 mol, 0.04 mol, and 0.10 mol.
And each said compound was mixed in acetone with the ball mill for 24 hours, respectively, and the mixture was produced.

Next, each mixture was calcined at 750 ° C. for 5 hours, and then each calcined mixture was ground in a ball mill for 24 hours. Subsequently, polyvinyl butyral was added as a binder and granulated.
Each granulated powder is pressure-molded into a disk shape having a diameter of 13 mm and a thickness of 2 mm at a pressure of ² ton / cm ² , and the resulting molded body is fired at a temperature of 1000 to 1300 ° C. for 1 hour. Was made. In addition, the specific calcination temperature at this time selected the temperature in which the sintered body of the maximum density is obtained by calcination for 1 hour within the above temperature range of 1000 ° C. to 1300 ° C. At this time, all the fired bodies were densified to a relative density of 98% or more.

Next, both sides of each fired body were subjected to parallel polishing and circular polishing, and then gold electrodes were provided on both sides of the disk sample by sputtering. Then, a DC voltage of 1 to 5 kV / mm was applied between the electrodes in 100 ° C. silicone oil for 10 minutes to polarize in the thickness direction to obtain a piezoelectric ceramic composition.
In this way, eleven types of piezoelectric ceramic compositions (samples E1 to E4 and samples F1 to F4 and samples G1 to G3) were produced. Table 1 shows the mixing ratio of raw materials and additives in each sample.
Each of the above samples was prepared by a method in which a metal element was substituted for K and Na in a compound represented by {Li _0.04 (K _0.5 Na _0.5 ) _0.95 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O ₃ . . That is, for example, in the sample E1, the composition is {Li _0.04 (K _0.5 Na _0.5 ) _0.94 Ca _0.01 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O ₃ .

In addition, as a method different from the manufacturing method of this example, a compound represented by the above {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O ₃ was prepared by firing, and this was pulverized. Similar to the samples E1 to E4, the samples F1 to F4, and the samples G1 to G3, even if they are mixed with the additives and then calcined, granulated, molded, and baked in the same manner as the manufacturing method of this example. A piezoelectric ceramic composition can be produced.

In Samples E1 to E4, Samples F1 to F4, and Samples G1 to G3 produced in this example, CaO, SrO, MgO, or BaO as the additive is partly an oxide or a perovskite structure compound. As a compound, it is contained in the grain or grain boundary of each piezoelectric ceramic composition, and a part of the compound is represented by the above {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O ₃ It is considered that at least a part of Li, K, and Na is contained in a state where Ca, Sr, Mg, or Ba atoms in each additive are substituted.

Next, in this example, in order to clarify the excellent characteristics of the piezoelectric ceramic composition, comparative products (sample C1 and sample C2) were produced as follows.
First, high purity Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ and Sb ₂ O ₅ having a purity of 99% or more were prepared as comparative materials.

Among these raw materials, K ₂ CO ₃ , Na ₂ CO ₃ , and Nb ₂ O ₅ are converted into the above general formula {Li _x (K _{1 -y} Na _y ) _1-x } (Nb _{1 -zw} Ta _z Sb _w ) O. ₃ , the stoichiometric ratio such that x = z = w = 0 and y = 0.5, that is, the stoichiometric ratio such that the general formula is (K _0.5 Na _0.5 ) NbO ₃ The mixture was then mixed in acetone for 24 hours by a ball mill to obtain a mixture.
This mixture was calcined, granulated, molded, fired, polarized in the same manner as Samples E1 to E4, Samples F1 to F4, and Samples G1 to G3, and then subjected to a piezoelectric ceramic composition (sample). C1) was produced.
Sample C1 is a piezoelectric ceramic composition containing (K _0.5 Na _0.5 ) NbO ₃ .

Next, the sample C2 is produced as follows.
First, the raw materials Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , and Sb ₂ O ₅ prepared above are subjected to the above general formula {Li _x ( in _{K 1-y Na y) 1} -x} (Nb 1-zw Ta z Sb w) O 3, x = 0.04, y = 0.5, and z = 0.1 and w = 0.04, Stoichiometric ratio, that is, a stoichiometric ratio such that the above general formula becomes a compound represented by {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O ₃ , The mixture was mixed in acetone with a ball mill for 24 hours to obtain a mixture.

This mixture was calcined, granulated, molded, fired, polarized in the same manner as Samples E1 to E4, Samples F1 to F4, and Samples G1 to G3, and then subjected to a piezoelectric ceramic composition (sample). C2) was prepared.
Sample C2 contains the compound {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O ₃ as the main component in the same manner as Samples E1 to E4, Samples F1 to F4, and Samples G1 to G3. On the other hand, it is a piezoelectric ceramic composition that does not contain the additive element.
Table 1 shows the composition ratio of the sample C1 and the sample C2.

Next, for the samples E1 to E4, samples F1 to F4, samples G1 to G3, samples C1 and C2, the piezoelectric d ₃₁ constant, the electromechanical coupling coefficient Kp, the piezoelectric g ₃₁ constant, the mechanical quality factor Qm, the ratio permittivity ε _33T / ε _0, dielectric loss tan [delta, and the Curie temperature Tc were measured.

The piezoelectric d ₃₁ constant, the piezoelectric g ₃₁ constant, the electromechanical coupling coefficient Kp, and the mechanical quality factor Qm were measured by a resonance-antiresonance method using an impedance analyzer (a precision impedance analyzer 4294A manufactured by Agilent).
The dielectric loss tan δ and relative dielectric constant ε _33T / ε ₀ were measured at a measurement frequency of 1 kHz using the same impedance analyzer as described above.
The Curie temperature Tc was defined as the temperature at which the relative dielectric constant ε _33T / ε ₀ was the highest.
The results are shown in Table 2.

As is known from Table 2, the samples E1 to E4, the samples F1 to F4, and the samples G1 to G3 have a piezoelectric d ₃₁ constant, an electromechanical coupling coefficient Kp, a relative dielectric constant ε _33T / ε ₀ and dielectric loss tan δ were improved.
The samples E1 to E4, the samples F1 to F4, and the samples G1 to G3 have a piezoelectric d ₃₁ constant, an electromechanical coupling coefficient Kp, a piezoelectric g ₃₁ constant, and a mechanical quality factor even when compared with the sample C2. qm, the relative dielectric constant ε _33T / ε _0, dielectric loss tan [delta, and any one or more of the Curie temperature Tc had equal or superior characteristics.
In Table 2, the effect when 0.02 mol or more of CaO is added is shown. Although not clearly shown in Table 2, it has been confirmed that the same effects as Ca can be obtained for other additive elements (Mg, Sr, Ba).

Here, focusing on the piezoelectric d ₃₁ constant, as known from Table 2, the piezoelectric d ₃₁ constant of sample F2 showed the highest value of 121.0pm / V.

When a charge detection circuit or a current detection circuit is used, the piezoelectric d ₃₁ constant is generally proportional to the output voltage of a piezoelectric sensor such as an acceleration sensor, a weight sensor, an impact sensor, or a knock sensor. From this point of view, a piezoelectric ceramic composition having a higher piezoelectric d ₃₁ constant can produce a sensor element having a larger charge sensor output. It can be said that it is preferable to have a piezoelectric d ₃₁ constant of at least 30 pm / V or more in order to produce a sensor element having characteristics equal to or higher than those of the sample C1 as a comparative product. To generate a highly sensitive sensor element is further enhanced signal-to-noise ratio (SN ratio) and the output voltage, the piezoelectric d ₃₁ constant good not less than 80 pm/V. More preferably, it is 100 pm / V or more.

When used as an actuator, the piezoelectric d ₃₁ constant is generally proportional to the generated strain or displacement of the piezoelectric actuator. From this point of view, a piezoelectric ceramic composition having a higher piezoelectric d ₃₁ constant can produce an actuator element having a larger strain or displacement. It can be said that it is preferable to have a piezoelectric d ₃₁ constant of at least 30 pm / V or more in order to manufacture an actuator element having characteristics equal to or higher than those of a comparative product. More preferably, it is 40 pm / V or more. In order to fabricate an actuator having a larger displacement, the piezoelectric d ₃₁ constant is preferably 80 pm / V or more. More preferably, it is 100 pm / V or more.

  Further, focusing on the electromechanical coupling coefficient Kp, as is known from Table 2, the electromechanical coupling coefficient Kp of the sample F2 showed the highest value of 0.551.

  In general, the electromechanical coupling coefficient Kp is proportional to the electromechanical energy conversion efficiency of a piezoelectric transformer element, an ultrasonic motor element, an actuator element, or an ultrasonic transducer. From this point, a piezoelectric transformer element, an ultrasonic motor element, an actuator element, or an ultrasonic transducer having a higher electromechanical energy conversion efficiency can be produced with a piezoelectric ceramic composition having a higher electromechanical coupling coefficient Kp. In order to manufacture a piezoelectric transformer element, an ultrasonic motor element, an actuator element, or an ultrasonic vibrator having characteristics equivalent to or better than those of the comparative sample C1, an electromechanical coupling coefficient Kp of at least 0.3 is required. It can be said that it is preferable. More preferably 0.34 or more. More preferably, 0.4 or more is good. Furthermore, 0.45 or more is more preferable.

  Further, when attention is paid to the mechanical quality factor Qm, as is known from Table 2, the mechanical quality factors Qm of the samples E1 to E4 and the samples G1 to G3 are equal to or superior to those of the samples C1 and C2. The value is shown.

  In general, the mechanical quality factor Qm is proportional to the electromechanical energy conversion efficiency of a piezoelectric transformer element, an ultrasonic motor element, an actuator element, an ultrasonic transducer, or the like, like the electromechanical coupling coefficient Kp. From this point, a piezoelectric transformer element, an ultrasonic motor element, an actuator element, or an ultrasonic transducer having a higher electromechanical energy conversion efficiency can be produced with a piezoelectric ceramic composition having a higher electromechanical coupling coefficient Kp. In order to manufacture a piezoelectric transformer element, ultrasonic motor element, actuator element, or ultrasonic transducer having characteristics equivalent to or better than the sample C1 as a comparative product, it must have a mechanical quality factor Qm of at least 50 or more. Is preferable.

Further, when paying attention to the Curie temperature Tc, the Curie temperatures Tc of the samples E1 to E4, the samples F1 to F4, and the samples G1 to G3 all take a high value of 200 ° C. or higher. Therefore, the piezoelectric ceramic composition (samples E1 to E4, samples F1 to F4, and samples G1 to G3) of this example is a knock that can be used stably for a long time even in a high temperature part such as the vicinity of an engine of an automobile. It can be used as high-temperature sensor parts such as sensors, actuator parts, ultrasonic motor parts, and the like.
Further, the Curie temperature Tc is preferably 200 ° C. or higher in order to be used stably for a long time as the high temperature sensor part, the actuator part, the ultrasonic motor part or the like. More preferably, the temperature is 250 ° C. or higher.

Moreover, focusing on the piezoelectric g ₃₁ constant, as known from Table 2, the piezoelectric g ₃₁ constant of sample F2 showed the highest value of 8.81 × 10 ^-3 Vm / N.

The piezoelectric g ₃₁ constant is proportional to the output voltage of a piezoelectric sensor, a piezoelectric transformer element, an ultrasonic motor element, etc., like the piezoelectric d ₃₁ constant. Therefore, a piezoelectric ceramic composition having a higher piezoelectric g ₃₁ constant can produce a sensor having a larger voltage sensor output. It can be said that it is preferable to have a piezoelectric g ₃₁ constant of at least 7 × 10 ⁻³ Vm / N or more in order to manufacture a sensor having characteristics equal to or higher than those of the comparative product. More preferably, 8 × 10 ⁻³ Vm / N or more is preferable.

Moreover, focusing on the dielectric constant ε _33T / ε _0, the relative dielectric constant ε _33T / ε ₀ of the sample E1~E4 and sample F1~F4 and sample G1~ sample G3 takes the very high value of 1300 or more Yes.

The relative dielectric constant ε _33T / ε ₀ is generally proportional to the capacitance of a capacitor such as a multilayer capacitor component. From this point of view, a piezoelectric ceramic composition having a higher relative dielectric constant can produce a capacitor having a larger capacitance. In order to manufacture a capacitor, it can be said that it is preferable to have a relative dielectric constant of at least 400 or more. More preferably, 430 or more is good. More preferably, 1000 or more are good.

  When attention is paid to the dielectric loss tan δ, the dielectric loss tan δ of the samples E1 to E4, the samples F1 to F4, and the samples G1 to G3 are very low values of 0.034 or less.

  The dielectric loss is proportional to the thermal energy lost by the component when an AC voltage is applied to a component such as a capacitor component, a piezoelectric ultrasonic motor, a piezoelectric actuator, or a piezoelectric transformer. From this point of view, a piezoelectric ceramic composition having a smaller dielectric loss can produce a capacitor with less energy loss and a piezoelectric ultrasonic motor, piezoelectric actuator, and piezoelectric transformer with less heat generation. And in order to produce the said component with little energy loss, it is preferable to have a dielectric loss of 0.09 or less. More preferably, 0.035 or less is good. More preferably, 0.03 or less is good.

  As described above, the piezoelectric ceramic composition of this example (sample E1 to sample E4 and sample F1 to sample F4 and sample G1 to sample G3) does not contain lead in the composition, and has excellent piezoelectric characteristics as described above. Has dielectric properties. Therefore, it can be used for high-performance piezoelectric elements and dielectric elements that are safe to the environment.

(Example 2)
In this example, the piezoelectric ceramic composition of the second invention (claim 3 ) is manufactured and its characteristics are measured.
The piezoelectric ceramic composition of this example is represented by the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3, and x, y, z, w Are piezoelectric ceramic compositions mainly composed of compounds in the composition ranges of 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, and 0 <w ≦ 0.2.
The piezoelectric ceramic composition contains any one or more metal elements selected from Si, In, and Sc as additive elements. And the sum total of content of the said additional element is 0.01 mol with respect to 1 mol of compounds represented by the said general formula.

The method for producing a piezoelectric ceramic composition of this example includes a compound containing Li, a compound containing Na, a compound containing K, a compound containing Nb, a compound containing Ta, and Sb. with a compound of the general formula after calcination _{{Li x (K 1-y} Na y) 1-x} is represented by _{(Nb 1-zw Ta z Sb} w) O 3, and x, y, z, w, respectively Prepared in a stoichiometric ratio so as to be a compound having a composition range of 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, 0 <w ≦ 0.2, and Si An additive containing at least one metal element selected from In, Sc, is mixed and fired.

Hereinafter, the manufacturing method of the piezoelectric ceramic composition of this example will be described.
First, as a raw material of the basic composition of the piezoelectric ceramic composition, high purity Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , Sb ₂ O ₅ having a purity of 99% or more. , And SiO ₂ , Sc ₂ O ₃ , and In ₂ O ₃ as the additive were prepared.

Among these raw materials, Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , Sb ₂ O ₅ are converted into the above general formula {Li _x (K _1-y Na _y ) _1−x } (Nb _1−zw Ta _z Sb _w ) O ₃ , x, y, z, w are x = 0.04, y = 0.5, z = 0.1, w = 0.04 to become such a stoichiometric ratio, i.e. blended in the above general formula _{{Li 0.04 (K 0.5 Na 0.5} ) 0.96} (Nb 0.86 Ta 0.1 Sb 0.04) O 3 and becomes such a stoichiometric ratio Further, SiO ₂ , Sc ₂ O ₃ , or In ₂ O ₃ as the additive was blended to obtain three types of blends.

The compounding amount of the additive, the stoichiometric compound is expected to be obtained after firing by blending at ratio _{{Li 0.04 (K 0.5 Na 0.5} ) 0.96} (Nb 0.86 Ta 0.1 Sb 0.04) O 3 1mol On the other hand, 0.01 mol, 0.005 mol, and 0.005 mol of SiO ₂ , Sc ₂ O ₃ , or In ₂ O ₃ as the additive were blended, respectively. That is, the additive amount of the additive was such that the additive amounts of Si, Sc, and In as additive elements were 0.01 mol.

And each said compound was mixed in acetone with the ball mill for 24 hours, respectively, and the mixture was produced.
Next, this mixture was calcined, granulated, molded, fired and polarized in the same manner as the samples E1 to E4 of Example 1 above, and three kinds of piezoelectric ceramic compositions (sample E5 to sample E7) were applied. ) Table 3 shows the mixing ratio of the raw materials and additives of each sample.

In addition, as a method different from the manufacturing method of this example, a compound represented by the above {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O ₃ was prepared by firing, and this was pulverized. The piezoelectric ceramic composition similar to the samples E5 to E7 can be produced by mixing with the additive and then performing calcination, granulation, molding and firing in the same manner as in the production method of this example.

In the samples E5 to E7 produced in this example, SiO ₂ , Sc ₂ O ₃ , or In ₂ O ₃ as the additive is partially a compound such as an oxide or a perovskite structure compound. It is contained in the grain boundary of the composition, and a part thereof is at least one of Nb, Ta, and Sb of the compound represented by {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O _3. Is considered to be contained in a state in which Si, Sc, or In atoms in each additive are substituted.

Next, for the samples E5 to E7, in the same manner as in Example 1, the piezoelectric d ₃₁ constant, the electromechanical coupling coefficient Kp, the piezoelectric g ₃₁ constant, the mechanical quality factor Qm, the relative dielectric constant ε _33T / ε ₀ , the dielectric The loss tan δ and the Curie temperature Tc were measured.
The results are shown in Table 4. Table 4 also shows various piezoelectric characteristics and dielectric characteristics of Sample C1 and Sample C2 produced in Example 1 for comparison.

As is known from Table 4, the samples E5 to E7 have significantly improved piezoelectric d ₃₁ constant, electromechanical coupling coefficient Kp, relative dielectric constant ε _33T / ε ₀ , and dielectric loss tan δ compared to sample C1. It was.
The samples E5 to E7 have an improved piezoelectric d ₃₁ constant, electromechanical coupling coefficient Kp, piezoelectric g ₃₁ constant, mechanical quality factor Qm, and dielectric loss tan δ even when compared with the sample C2. The relative dielectric constant ε _33T / ε ₀ and the Curie temperature Tc were also equal or better.
Table 4 shows that the piezoelectric ceramic composition containing 0.01 mol of the additive element has excellent piezoelectric characteristics. Although not explicitly shown in Table 4, it has been confirmed that the same effect as described above can be obtained even when the content of the additive element is changed in the range of 0.001 to 0.08 mol.

  Thus, the piezoelectric ceramic composition (samples E5 to E7) of this example does not contain lead in the composition and has excellent piezoelectric characteristics and dielectric characteristics as described above. Therefore, it can be used for high-performance piezoelectric elements and dielectric elements that are safe to the environment.

(Example 3)
In this example, the piezoelectric ceramic composition of the third invention (invention 4) is manufactured, and its characteristics are measured.
The piezoelectric ceramic composition of this example is represented by the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3, and x, y, z, w Are piezoelectric ceramic compositions mainly composed of compounds in the composition ranges of 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, and 0 <w ≦ 0.2. The piezoelectric ceramic composition contains Bi as an additive element. And content of the said additional element is 0.0001 mol-0.004 mol with respect to 1 mol of compounds represented by the said general formula.

The method for producing a piezoelectric ceramic composition of this example includes a compound containing Li, a compound containing Na, a compound containing K, a compound containing Nb, a compound containing Ta, and Sb. with a compound of the general formula after calcination _{{Li x (K 1-y} Na y) 1-x} is represented by _{(Nb 1-zw Ta z Sb} w) O 3, and x, y, z, w, respectively Prepared in a stoichiometric ratio such that the compound is in the composition range of 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, 0 <w ≦ 0.2, and Bi Add the additive containing and fire.

Hereinafter, the manufacturing method of the piezoelectric ceramic composition of this example will be described.
First, as a raw material of the basic composition of the piezoelectric ceramic composition, high purity Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , Sb ₂ O ₅ having a purity of 99% or more. , And Bi ₂ O ₃ as an additive were prepared.

Among these raw materials, Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , Sb ₂ O ₅ are converted into the above general formula {Li _x (K _1-y Na _y ) _1−x } (Nb _1−zw Ta _z Sb _w ) O ₃ , x, y, z, w are x = 0.04, y = 0.5, z = 0.1, w = The stoichiometric ratio is _0.04 , that is, the stoichiometric ratio is such that the above general formula is {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O _3. Further, Bi ₂ O ₃ as the above additive was blended in various amounts to obtain four types of blends.

The compounding amount of the additive, the stoichiometric compound is expected to be obtained after firing by blending at ratio _{{Li 0.04 (K 0.5 Na 0.5} ) 0.96} (Nb 0.86 Ta 0.1 Sb 0.04) O 3 1mol In contrast, Bi ₂ O ₃ as an additive was blended in 0.00025 mol, 0.0005 mol, 0.0025 mol, or 0.005 mol. That is, the compounding amount of the additive was such that bismuth was included at 0.0005 mol, 0.001 mol, 0.005 mol, or 0.01 mol, respectively.

And each said compound was mixed in acetone with the ball mill for 24 hours, respectively, and the mixture was produced.
Next, this mixture was calcined, granulated, molded, fired and polarized in the same manner as the samples E1 to E4 and the samples F1 to F4 of Example 1 to obtain four types of piezoelectric ceramic compositions ( Samples E8 to E11) were obtained. Table 5 shows the mixing ratio of the raw materials and additives of each sample.

In addition, as a method different from the manufacturing method of this example, a compound represented by the above {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O ₃ was prepared by firing, and this was pulverized. A piezoelectric ceramic composition similar to that of the samples E8 to E11 can be produced by mixing with the additive and then performing calcination, granulation, molding and firing in the same manner as in the production method of this example.

In the samples E8 to E11 produced in this example, Bi as the additive element is partially contained in the grains or grain boundaries of each piezoelectric ceramic composition as a compound such as an oxide or a perovskite structure compound. In addition, a part of Nb, Ta, and Sb in the compound represented by {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O ₃ is substituted with Bi atoms. It is thought that it is included in the state.

Next, for the samples E8 to E11, as in Example 1, the piezoelectric d ₃₁ constant, the electromechanical coupling coefficient Kp, the piezoelectric g ₃₁ constant, the mechanical quality factor Qm, the relative dielectric constant ε _33T / ε ₀ , the dielectric The loss tan δ and the Curie temperature Tc were measured.
The results are shown in Table 6. Table 6 also shows various piezoelectric characteristics and dielectric characteristics of Sample C1 and Sample C2 produced in Example 1 for comparison.

As is known from Table 6, the samples E8 and E9 have significantly improved piezoelectric d ₃₁ constant, electromechanical coupling coefficient Kp, relative permittivity ε _33T / ε ₀ , and dielectric loss tan δ compared to sample C1. It was.
In addition, the samples C8 and E9 have an improved piezoelectric d ₃₁ constant, electromechanical coupling coefficient Kp, and relative dielectric constant ε _33T / ε _{0 as} compared with the sample C2, and other characteristics are equivalent or equivalent. It was better than that. In addition, the dielectric loss tan δ piezoelectric g ₃₁ constant, the mechanical quality factor Qm, the dielectric loss tan δ, and the Curie temperature Tc showed excellent characteristics equivalent to or better than those of the sample C1.

On the other hand, the sample E10 had significantly improved piezoelectric d ₃₁ constant, relative permittivity ε _33T / ε ₀ , and dielectric loss tan δ compared to the sample C1. In addition, the mechanical quality factor Qm and the relative dielectric constant ε _33T / ε ₀ were improved as compared with the sample C2. However, on the other hand, the electromechanical coupling coefficient Kp and the piezoelectric g ₃₁ constant were greatly reduced.
The sample E11 has an improved mechanical quality factor Qm, relative permittivity ε _33T / ε ₀ and dielectric loss tan δ as compared to the sample C1, and the mechanical quality factor Qm is higher than that of the sample C2. On the other hand, the piezoelectric d ₃₁ constant, the electromechanical coupling coefficient Kp, the piezoelectric g ₃₁ constant, and the like were significantly reduced.

  Thus, the piezoelectric ceramic composition (sample E8 and sample E9) of this example does not contain lead in the composition, and has excellent piezoelectric characteristics and dielectric characteristics as described above. Therefore, it can be used for high-performance piezoelectric elements and dielectric elements that are safe to the environment.

Further, in this example, although not specifically shown, it has been confirmed that the effect of the above-described additive element is similarly exhibited even with a small content of 0.0001 mol. Further, it has been confirmed that the effect of the additive element can improve the piezoelectric characteristics in the same manner regardless of whether the additive is added or not.
Further, in this example, the piezoelectric ceramic composition mainly composed of a compound having a specific composition was confirmed to improve the piezoelectric characteristics by the additive element, but the general formula {Li _x (K _1-y Na _y ) for even _{1-x} (Nb 1-} zw Ta z Sb w) piezoelectric ceramic composition composed mainly of other compounds represented by O _3, it was confirmed that can exhibit the same effect.

Claims (11)

It is represented by the general formula _{{Li x (K 1-y} Na y) 1-x} a (Nb 1-zw Ta z Sb w) b O 3, and x, y, z, w, a, b are respectively 0 <X ≦ 0.2, 0.05 ≦ y ≦ 1, 0 <z ≦ 0.4, 0 <w ≦ 0.2, 0.95 ≦ a, b ≦ 1.05 A piezoelectric ceramic composition comprising:
The piezoelectric ceramic composition contains any one or more metal elements selected from Mg, Ca, Sr, and Ba as additive elements,
The total content of the additive elements is 0.0001 mol to 0.10 mol with respect to 1 mol of the compound represented by the general formula,
A piezoelectric ceramic composition having a piezoelectric d ₃₁ constant of 80 pm / V or more and a Curie temperature Tc of 200 ° C. or more.   2. The piezoelectric ceramic composition according to claim 1, wherein the additive element is substituted for at least a part of Li, K, and Na of the compound represented by the general formula. It is represented by the general formula _{{Li x (K 1-y} Na y) 1-x} a (Nb 1-zw Ta z Sb w) b O 3, and x, y, z, w, a, b are respectively 0 <X ≦ 0.2, 0.05 ≦ y ≦ 1, 0 <z ≦ 0.4, 0 <w ≦ 0.2, 0.95 ≦ a, b ≦ 1.05 A piezoelectric ceramic composition comprising:
The piezoelectric ceramic composition contains any one or more metal elements selected from Si, In, and Sc as an additive element,
The total content of the additive elements is 0.0001 mol or more and 0.08 mol or less with respect to 1 mol of the compound represented by the general formula,
A piezoelectric ceramic composition having a piezoelectric d ₃₁ constant of 80 pm / V or more and a Curie temperature Tc of 200 ° C. or more. It is represented by the general formula _{{Li x (K 1-y} Na y) 1-x} a (Nb 1-zw Ta z Sb w) b O 3, and x, y, z, w, a, b are respectively 0 <X ≦ 0.2, 0.05 ≦ y ≦ 1, 0 <z ≦ 0.4, 0 <w ≦ 0.2, 0.95 ≦ a, b ≦ 1.05 A piezoelectric ceramic composition comprising:
The piezoelectric ceramic composition contains Bi as an additive element,
The content of the additive element is 0.0001 mol to 0.004 mol with respect to 1 mol of the compound represented by the general formula,
In the piezoelectric d ₃₁ constant 80 pm / V or more, and a piezoelectric ceramic composition Curie temperature Tc is equal to or is 200 ° C. or higher.   The piezoelectric ceramic composition according to any one of claims 1 to 4, wherein the piezoelectric ceramic composition has an electromechanical coupling coefficient Kp of 0.30 or more. 6. The piezoelectric ceramic composition according to claim 1, wherein the piezoelectric ceramic composition has a piezoelectric g ₃₁ constant of 7 × 10 ⁻³ Vm / N or more.   The piezoelectric ceramic composition according to any one of claims 1 to 6, wherein the piezoelectric ceramic composition has a mechanical quality factor Qm of 50 or more.   The piezoelectric ceramic composition according to claim 1, wherein the piezoelectric ceramic composition has a relative dielectric constant of 400 or more.   The piezoelectric ceramic composition according to any one of claims 1 to 8, wherein the piezoelectric ceramic composition has a dielectric loss of 0.09 or less.   A piezoelectric element comprising the piezoelectric ceramic composition according to claim 1.   A dielectric element comprising the piezoelectric ceramic composition according to any one of claims 1 to 9.