WO2017181912A1

WO2017181912A1 - Lead-free piezoelectric ceramic material and lead-free piezoelectric component

Info

Publication number: WO2017181912A1
Application number: PCT/CN2017/080593
Authority: WO
Inventors: 李�权; 聂泳忠
Original assignee: 西人马（厦门）科技有限公司
Priority date: 2016-04-22
Filing date: 2017-04-14
Publication date: 2017-10-26
Also published as: CN105924155A

Abstract

A lead-free piezoelectric ceramic material and lead-free piezoelectric component. The piezoelectric ceramic material comprises a substrate. The substrate is a layered bismuth-based compound. The substrate is doped with at least one of the following: a niobium component and a cerium component.

Description

Lead-free piezoelectric ceramic materials and lead-free piezoelectric components

Technical field

The present disclosure relates to electronic ceramic materials, and more particularly to tantalum layered lead-free piezoelectric ceramic materials and piezoelectric elements.

Background technique

With the development of science and technology, many industrial equipments have become more and more demanding on the use range and use conditions of piezoelectric devices. High-power ultrasonic devices, high-temperature ultrasonic waves, high-temperature object vibration, acceleration and pressure measurement must be selected with high temperature pressure. Electrical material. At present, piezoelectric ceramic materials that can be used in high temperature (greater than 400 ° C) environment at home and abroad mainly use lead-free piezoelectric ceramics with bismuth layer structure. However, the piezoelectric activity of conventional lead-free piezoelectric materials with bismuth layer structure is related to temperature. The drift is large and is not suitable for high temperature working environments.

Summary of the invention

According to an aspect of the present disclosure, a lead-free piezoelectric ceramic material is provided, including a base material which is a bismuth layer structure compound, and the base material is doped with at least one of a component lanthanum and a component lanthanum Kind.

According to another aspect of the present disclosure, a lead-free piezoelectric element including a lead-free piezoelectric ceramic material, wherein the lead-free piezoelectric ceramic material includes a base material, the base material is a bismuth layer structure compound, and the base body The material is doped with at least one of component hydrazine and component hydrazine.

The bismuth layered lead-free piezoelectric ceramic material and the lead-free piezoelectric element according to the present disclosure have good piezoelectric properties under high temperature conditions, and thus are suitable for use in a high temperature environment.

DRAWINGS

The features and advantages of the embodiments of the present disclosure will be more clearly understood by reference to the accompanying drawings.

1 is a schematic structural view showing a tantalum layered lead-free piezoelectric ceramic material according to some exemplary embodiments of the present disclosure;

2 is a flow chart illustrating a method of preparing a bismuth layered lead-free piezoelectric ceramic material, in accordance with some exemplary embodiments of the present disclosure;

3 is a more detailed flowchart showing a method of preparing a bismuth layered lead-free piezoelectric ceramic material according to further exemplary embodiments of the present disclosure;

4 is a graph showing an aging rate as a composite doping content of a bismuth layered lead-free piezoelectric ceramic material, in accordance with some exemplary embodiments of the present disclosure;

FIG. 5 is a graph showing sensitivity drift-temperature characteristics of a tantalum layered lead-free piezoelectric ceramic material before and after doping substitution modification, according to some exemplary embodiments of the present disclosure.

detailed description

The detailed description of the embodiments of the present invention is intended to However, it will be apparent to those skilled in the art that the present invention may be practiced without some of these details. The following description of the embodiments is merely intended to provide a further understanding of the embodiments. The present disclosure is in no way limited to any specific configuration, which is set forth below, but without departing from the spirit and scope of the disclosure.

In some embodiments, the lead-free piezoelectric ceramic material according to the present disclosure includes a base material that is a bismuth layered structural compound, and the base material is doped with at least one of a component lanthanum and a component lanthanum. According to the lead-free piezoelectric ceramic material and the piezoelectric element of the present disclosure, the base material is doped and modified by at least one of the component 铌 and the component ,, and thus has good piezoelectric properties under high temperature conditions, thereby being suitable for Use in high temperature environment.

A layered lead-free piezoelectric ceramic material according to some embodiments of the present disclosure will now be described with reference to FIG. As shown in FIG. 1, the piezoelectric ceramic material includes a base material 100 which is a bismuth layer structure including a perovskite structure layer 101 and a ruthenium oxide layer 102, wherein the perovskite structure layer 101 The silicon oxide layer 102 is staggered.

With continued reference to FIG. 1, in some embodiments, the perovskite-type structural layer 101 and the tantalum oxide layer 102 are staggered along the c-axis direction of the base material 100, wherein between each two layers of the silicon oxide layer 102 to There is one layer of perovskite structure. In general, as the number of perovskite-type structural layers between each two layers of the tantalum oxide layer 102 increases, the piezoelectric activity of the piezoelectric ceramic material increases, and the structure tends to be single crystal, and the Curie point Tc High, the lower the aging rate, the higher the resistivity.

In some embodiments, the base material may be a bismuth layer structure having the general formula (Bi ₂ O ₂ ) ²⁺ (A _m-1 B _m O _3m+1 ) ^2- , wherein (Bi ₂ O ₂ ²⁺ represents a ruthenium oxide layer, (A _m- ₁ B _m O _3m+1 ) ^2- represents a perovskite-type structural layer, and wherein m represents between every two layers (Bi ₂ O ₂ ) ²⁺ ( A _m-1 B _m O _3m+1 ) The number of ^2- .

In some embodiments, the base material 100 may be Na _0.5 Bi _4.5 Ti ₄ O ₁₅ , which has the general formula (Bi ₂ O ₂ ) ²⁺ (Na _0.5 Bi _2.5 Ti ₄ O ₁₃ ) ^2- , Perovskite-type structural layer (Na _0.5 Bi _2.5 Ti ₄ O ₁₃ ) ^2- and bismuth oxide layer (Bi ₂ O ₂ ) ²⁺ are staggered along the c-axis direction, and there are 4 layers of calcium between each two layers of bismuth oxide layer. Titanium ore layer.

In other embodiments, the base material 100 may be Na _0.5 Bi _3.5 Ti ₃ O ₁₂ , which has the formula (Bi ₂ O ₂ ) ²⁺ (Na _0.5 Bi _1.5 Ti ₃ O ₁₀ ) ^2- , and the structure is It is formed by staggering the perovskite structure layer (Na _0.5 Bi _1.5 Ti ₃ O ₁₀ ) ^2- and the bismuth oxide layer (Bi ₂ O ₂ ) ²⁺ along the c-axis direction, and there are 3 layers between each two layers of 铋 oxygen layer. Perovskite layer.

As described above, according to the piezoelectric ceramic material of the present disclosure, the base material 100 may be doped by at least one of the outer doping component 铌Nb and the component 铈Ce. In some embodiments, the component 铌Nb may be derived from yttrium oxide Nb ₂ O ₅ and the doping amount of the component 铌Nb is converted to Nb ₂ O ₅ . In some embodiments, the component 铈Ce may be derived from cerium oxide CeO ₂ and the composition 铈Ce doping amount is converted in terms of CeO ₂ . It should be understood that although Nb, Ce is exemplified by Nb ₂ O ₅ , CeO ₂ in the present disclosure, it is not limited to this specific oxide, and other ruthenium compounds and ruthenium compounds may be employed.

In some embodiments, the base material 100 may be doped with ruthenium oxide or ruthenium oxide alone, or the base material 100 may be doped with both ruthenium oxide and ruthenium oxide. The doping amount of cerium oxide may be not more than 7 mol%, and the doping amount of cerium oxide may be not more than 2 wt%. It should be understood that mol% is a mole percent and wt% is a weight percent, both relative to the matrix material.

For example, in the case where the base material 100 is doped with yttrium oxide Nb ₂ O ₅ alone, the piezoelectric ceramic material can be expressed as Na _0.5 Bi _4.5 Ti ₄ O ₁₅ +x mol% Nb ₂ O ₅ , where 0<x≤7 . Further, in the case where the base material 100 is doped with CeO ₂ alone, the piezoelectric ceramic material may be expressed as Na _0.5 Bi _4.5 Ti ₄ O ₁₅ + y wt% CeO ₂ , where 0 < y ≤ 2. Further, in the case where the base material 100 is doped with Nb ₂ O ₅ and CeO ₂ , the piezoelectric ceramic material may be expressed as Na _0.5 Bi _4.5 Ti ₄ O ₁₅ + x mol% Nb ₂ O ₅ + y wt % CeO ₂ , Where 0<x≤7;0<y≤2, the composite doping of Nb ₂ O ₅ and CeO ₂ can make the piezoelectric constant d _{33 of the} matrix Na _0.5 Bi _4.5 Ti ₄ O ₁₅ reach 35 pC/N, piezoelectric activity Significant improvements have been made.

In some embodiments, the base material 100 may also be substituted with at least one of the component 锶Sr and the component 钡Ba, and the 锶Sr may be taken from strontium carbonate SrCO ₃ , which may be taken from Barium carbonate BaCO ₃ . In this case, a portion of Na ⁺ in the base material 100 may be substituted with at least one of Sr ²⁺ and Ba ²⁺ . That is, part of the Na ions may be substituted by Sr ²⁺ , or part of the Na ions may be substituted by Ba ²⁺ , or part of the partial Na ions may be substituted by Sr ²⁺ and the other part by Ba ²⁺ . Although Sr, Ba is exemplified by SrCO ₃ and BaCO _{3 in the} present disclosure, the present disclosure is not limited thereto, and other ruthenium compounds and ruthenium compounds may be employed.

As an example, in the case where the base material 100 is doped with both Nb ₂ O ₅ and CeO ₂ , Sr ²⁺ replaces the portion Na ⁺ , and at this time, the piezoelectric ceramic material can be expressed as (Na _0.5- _z Sr _z ) Bi _4.5 Ti ₄ O ₁₅ +x mol% Nb ₂ O ₅ +y wt%CeO ₂ , where 0<x≤7, 0<y≤2, 0<z<0.5).

As another example, in the case where the base material 100 is doped with both Nb ₂ O ₅ and CeO ₂ , Ba ²⁺ replaces the portion Na ⁺ , and at this time, the piezoelectric ceramic material can be expressed as (Na _0.5- _w Ba _w )Bi _4.5 Ti ₄ O ₁₅ +x mol%Nb ₂ O ₅ +y wt%CeO ₂ , wherein 0<x≤7, 0<y≤2, 0<w<0.5).

In yet another example, in the case where the base material 100 is doped with both Nb ₂ O ₅ and CeO ₂ , part of the partial Na ⁺ is replaced by Sr ²⁺ , and the other part is substituted by Ba ²⁺ , In time, the piezoelectric ceramic material can be expressed as (Na _0.5-zw Sr _z Ba _w )Bi _4.5 Ti ₄ O ₁₅ +x mol%Nb ₂ O ₅ +y wt%CeO ₂ (0<x≤7,0<y ≤ 2, 0 < z < 0.5, 0 < w < 0.5, 0 < z + w < 0.5), the composite doped and substituted matrix material Na _0.5 Bi _4.5 Ti ₄ O ₁₅ piezoelectric constant d ₃₃ value can reach 28pC /N, then the piezoelectric ceramic material is aged at 550 ° C for 48 h, and then subjected to high temperature and low temperature -55 ° C ~ 120 ° C cycle aging treatment, d ₃₃ value is 24 pC / N; finally heated to 480 ° C for 24 h, high temperature insulation The resistance value is greater than 1.4 Ω, and the piezoelectric properties of the piezoelectric ceramic material and the piezoelectric element are significantly improved in high temperature anti-aging properties, high-temperature insulation resistance values, and piezoelectric activity.

It should be noted that Sr ²⁺ and Ba ²⁺ are only substituted for part of Na ⁺ , so in the presence of both, the total number of moles of the two cannot exceed the total number of moles of Na ⁺ substituted.

It should be noted that "outer doping" in the present disclosure means that although the doping element enters into the matrix material, it does not occupy the lattice position of any existing element; and "substitution doping" refers to not only the doping ion but also the dopant ion. Will enter the matrix material and will also occupy the lattice location of the particular element (eg Na ⁺ ). "External doping" and "substitute doping" are two doping methods for doping modification of the lead-free piezoelectric ceramic material in the present disclosure, and the compound participating in the doping modification is not limited to the doping described in the examples. Miscellaneous methods. In other embodiments of the present disclosure, those skilled in the art may also substitute the piezoelectric ceramic compound for doping modification using at least one of cerium oxide or cerium oxide. In still other embodiments of the present disclosure, the art The skilled person can externally dope the piezoelectric ceramic material with at least one of cesium carbonate or cesium carbonate. Doping modification of piezoelectric ceramic materials by Nb, Ce, Sr and Ba elements is not limited to a specific doping method.

In some other embodiments of the present disclosure, the base material may also be other bismuth layered lead-free piezoelectric ceramic material, such as Na _0.5 Bi _3.5 Ti ₃ O ₁₂ , doped outside the base material Na _0.5 Bi _3.5 Ti ₃ O ₁₂ . In the case of both Nb ₂ O ₅ and CeO ₂ , part of the Na ⁺ is replaced by Sr ²⁺ , and the other part is substituted by Ba ²⁺ , at which time the piezoelectric ceramic material can be expressed as (Na _{0.5 -z-} _w Sr _z Ba _w )Bi _3.5 Ti ₃ O ₁₂ +x mol%Nb ₂ O ₅ +y wt%CeO ₂ (0<x≤7,0<y≤2,0<z<0.5,0<w<0.5,0<z+w<0.5), the piezoelectric ceramic material Na _0.5 Bi _3.5 Ti ₃ O ₁₂ is doped and modified by Nb, Ce, Sr and Ba elements to improve the piezoelectric properties of piezoelectric ceramic materials. .

As described above, according to the lead-free piezoelectric ceramic material and the piezoelectric element of the embodiment of the present disclosure, the piezoelectric activity of the piezoelectric ceramic material and the piezoelectric element due to the doping component 铌 and/or component 铈 in the base material Can be improved. In addition, the substitution of Na ⁺ in the matrix material by Sr ²⁺ and/or Ba ²⁺ improves the high-temperature anti-aging property and high-temperature insulation resistance of the piezoelectric ceramic material and the piezoelectric element.

The process of preparing a piezoelectric ceramic material according to some embodiments of the present disclosure will be described in detail below with reference to FIGS. 2-3. It should be noted that these examples are not intended to limit the scope of the disclosure.

2 is a flow chart showing a method 100 of preparing a bismuth layered lead-free piezoelectric ceramic material, in accordance with some exemplary embodiments of the present disclosure. As shown in FIG. 2, piezoelectric preparation according to an embodiment of the present disclosure The method 200 of ceramic material includes the following steps S201-S206.

In step S201, at least one of a predetermined proportion of cerium oxide and cerium oxide, cerium oxide, anhydrous sodium carbonate, and titanium dioxide powder are thoroughly mixed.

In step S202, the sufficiently mixed material is pre-sintered.

In step S203, the pre-sintered block is mashed and finely ground.

In step S204, the finely ground material is granulated.

In step S205, the granulated powder is press-formed.

In step S206, the molded body is subjected to high temperature sintering.

The piezoelectric ceramic material prepared according to the method of the embodiments of the present disclosure can be suitably used in a high temperature, high frequency environment.

3 is a more detailed flowchart showing a method of preparing a bismuth layered lead-free piezoelectric ceramic material according to some exemplary embodiments of the present disclosure, and the same or equivalent steps of FIG. 3 and FIG. 2 use the same reference numerals.

In this step, first, the percentage of each raw material is calculated according to the molecular formula of the lead-free piezoelectric ceramic material to be obtained, and the corresponding amounts of various raw materials are weighed.

In some embodiments, the step of sufficiently mixing in step S201 may further include:

In step S2011, at least one of a predetermined ratio of cerium oxide and cerium oxide, cerium oxide, anhydrous sodium carbonate, and titanium dioxide powder are initially mixed.

In one example, the preliminary mixing can be performed by using a ball milling method. As an example, at least one of the weighed predetermined amount of cerium oxide and cerium oxide, cerium oxide, anhydrous sodium carbonate, and titanium dioxide raw material is loaded into the ball mill according to the ratio of raw material: grinding ball: alcohol = 1:2:0.7. In the tank, the ball mill was mixed at a speed of 90 rpm. The ball milling time can be, for example, 6 to 8 hours. It should be understood that in the case of ball mill mixing, it is also necessary to dry the ball milled material. As an example, the mixed material was placed in a blast drying oven and dried at 80 °C. The drying time can be, for example, 12 to 14 hours.

In step S2012, the preliminary mixed material is crushed and compacted. In one example, the briquetting treatment can be carried out at a pressure of 0.8 to 1 t/cm ² .

After step S2011-S2012, a well mixed material is obtained.

In step S202, the sufficiently mixed material is pre-sintered. In one example, the pre-sintering temperature can be pre-fired at 830-870 ° C, for example 850 ° C for 2 to 3 h.

In step S203, the pre-sintered block is mashed and finely ground.

In one example, the pre-sintered mass is chopped and the chopped powder is finely ground. For example, the pulverized powder is placed in a ball mill tank at a ratio of powder:grinding ball:alcohol = 1:1.5:0.7, and the powder is finely ground at a number of revolutions of 90 rpm. The ball milling time can be, for example, 22 to 26 hours. It should be understood that in the case of ball mill mixing, it is also necessary to dry the ball milled material. As an example, the mixed material was placed in a blast drying oven and dried at 80 °C. The drying time can be, for example, 12 to 14 hours.

In step S204, the finely ground material is granulated. In some embodiments, a binderless granulation technique can be employed. In some embodiments, a granulation technique using a binder can be employed. At this time, the binder used may be, for example, polyvinyl alcohol PVA. As an example, in the granulation treatment, the finely pulverized material may be added to 5 to 6% of polyvinyl alcohol PVA for granulation.

In step S205, the granulated powder is press-formed. As an example, in this step, the granulated powder is dry-formed under a pressure of 1.5 to 2 t/cm ² .

In step S206, the molded body is subjected to high temperature sintering. As an example, in this step, the formed green body is placed in a heating furnace, raised to a temperature of 300 ° C / h to 1100 ~ 1150 ° C, and kept for 2 h. After cooling with the furnace, a piezoelectric ceramic material is obtained.

It should be understood that in the case of granulation using an adhesive, in order to avoid the influence of the adhesive, the molded body after press molding is subjected to a low temperature displacement treatment to remove the binder.

As an example, in the plasticizing treatment, the formed blank is placed in a heating furnace, raised to 100 ° C at a heating rate of less than 100 ° C / h, held for 1 h, and then heated to 500 ° C at the same heating rate, The adhesive is basically removed. In order to increase the strength of the green body, heating can be continued until the temperature is raised to 850 ° C and kept for 1 h.

According to the method of the above embodiment, a piezoelectric ceramic material having a bismuth layer structure as a base and externally doped with at least one of cerium oxide and cerium oxide can be prepared, and the piezoelectric ceramic material can be adapted to high temperature and high frequency. Used in the environment. It should be understood that the specific preparation conditions in the respective steps are described above by way of examples, but it should be understood that these are merely examples, and the disclosure is not limited to the specific Value. In some examples, in order to further enhance the performance of the piezoelectric ceramic material in a high-temperature high-frequency environment, it is also possible to add a raw material such as barium carbonate and/or barium carbonate in the mixing step to obtain a germanium and/or a germanium which is doped externally. The element is a piezoelectric ceramic material in which sodium Na ions are replaced by strontium Sr and/or strontium Ba ions.

None of the above raw materials were subjected to purification treatment. The purity of cerium oxide, cerium oxide and cerium oxide is 99.9%, and the purity of anhydrous sodium carbonate, titanium dioxide, cesium carbonate, cesium carbonate and absolute ethanol can be analytically pure.

In order to test various properties of the piezoelectric ceramic material obtained according to the above production method, the obtained material may be machined into a standard wafer and subjected to treatment by silver, silver burning, polarization, high temperature aging, or the like.

Table 1 below shows a piezoelectric ceramic material (Na _0.5-z- _w Sr _z Ba _w )Bi _4.5 Ti ₄ O ₁₅ +x mol% Nb ₂ O ₅ +y wt%CeO obtained according to an exemplary embodiment of the present disclosure. ₂ (10 < x ≤ 7, 0 < y ≤ ₂ , 0 < z < 0.5, 0 < w < 0.5, 0 < z + w < 0.5) the main performance parameters.

Table 1

As can be seen from the above Table 1, a piezoelectric ceramic material obtained by externally doping a lanthanum and/or lanthanum element and replacing a part of sodium Na ions with yt Sr and/or yt Ba ions has a Curie of 730 ° C according to an exemplary embodiment of the present disclosure. At a high temperature of 550 ° C for 48 hours, the normal temperature equivalent piezoelectric constant d ₃₃ is 23 to 25 pC / N, and the piezoelectric properties of the piezoelectric ceramic material and the piezoelectric element are remarkably improved, so that it can be suitably used for high temperature use. And because the relative dielectric constant is low, the piezoelectric ceramic material and the piezoelectric element have good dielectric properties at high frequencies, and can be adapted for use at high frequencies.

In addition, FIG. 4 is a graph showing an aging rate as a function of doping content of a composite doped and substituted bismuth layered lead-free piezoelectric ceramic material, according to some exemplary embodiments of the present disclosure. The composite doping in FIG. 4 means that the base material is doped with at least one of cerium oxide, cerium oxide, cerium carbonate, and cerium carbonate. As shown in FIG. 4, when the composite doping amount is 0.3 to 0.7% by weight, the aging rate of Na _0.5 Bi _4.5 Ti ₄ O ₁₅ is 25% or less, so that the stability of the piezoelectric material is good. In addition, as shown in FIG. 4, the aging rate of Na _0.5 Bi _4.5 Ti ₄ O ₁₅ decreases first and then increases with the composite doping amount. When the composite doping amount is 0.5 (wt)%, the aging rate is the lowest, which is stability. A better piezoelectric ceramic material.

In addition, FIG. 5 is a graph showing sensitivity drift-temperature characteristics of a tantalum layered lead-free piezoelectric ceramic material before and after doping substitution modification, according to some exemplary embodiments of the present disclosure. As shown in Fig. 5, from about 250 ° C to 500 ° C, the sensitivity drift of the bismuth layered lead-free piezoelectric ceramic material increases with increasing temperature, and after the composite doping substitution modification of the matrix material, the temperature exceeds At 250 ° C, the sensitivity drift of the piezoelectric ceramic material is significantly improved.

In still other embodiments of the present disclosure, the piezoelectric ceramic material Na _0.5 Bi _3.5 Ti ₃ O _{12 is} doped with yttrium and/or lanthanum elements and is modified by replacing some sodium ions with 锶Sr and/or 钡Ba ions. After having a Curie point of 670 ° C, and the normal temperature equivalent piezoelectric constant d ₃₃ is 17 to 20 pC / N after aging at 550 ° C for 48 h, the piezoelectric properties of the piezoelectric ceramic material and the piezoelectric element are significantly improved. Used in high temperature. And the piezoelectric ceramic material has a low relative dielectric constant of 120 to 140 after high temperature aging treatment, so the piezoelectric ceramic material and the piezoelectric element have good dielectric properties at high frequencies, and can be adapted to high frequency. Used in.

As described above, the present disclosure describes a piezoelectric ceramic material and a piezoelectric element which can be externally doped by Nb, Ce, Sr, and Ba in a matrix material of a bismuth layered structure. And/or ion substitution, so that piezoelectric ceramic materials and piezoelectric elements have better piezoelectric activity, time and temperature stability, and high-temperature insulation resistance values even in a high-temperature environment, thereby making piezoelectric ceramic materials and piezoelectrics The component can be applied to high temperature rings such as high temperature piezoelectric devices In the realm.

Other embodiments of the present disclosure will be apparent to those skilled in the <RTIgt; The present application is intended to cover any variations, alternatives, or adaptations of these embodiments, which are in accordance with the general principles of the present disclosure and include common general knowledge or conventional techniques in the art that are not disclosed in the present disclosure. means.

It is to be understood that the invention is not limited to the details of the details and The description and examples are to be considered as illustrative only. The scope of the disclosure is to be limited only by the appended claims.

Claims

A lead-free piezoelectric ceramic material comprising: a base material which is a bismuth layer compound, and the base material is doped with at least one of a component lanthanum and a component lanthanum.
The lead-free piezoelectric ceramic material according to claim 1, wherein the base material is Na 0.5 Bi 4.5 Ti 4 O 15 or Na 0.5 Bi 3.5 Ti 3 O 12 .
The lead-free piezoelectric ceramic material according to claim 2, wherein said component is extracted from cerium oxide Nb 2 O 5 and said component is extracted from cerium oxide CeO 2 .
The lead-free piezoelectric ceramic material as claimed in claim 1, wherein said component content of niobium Nb 2 O 5 by the meter, the Nb 2 O 5 with respect to the content of the base material is not more than 7mol%.
The lead-free piezoelectric ceramic material according to claim 1, wherein a content of the component cerium is not more than 2% by weight based on the CeO 2 content of the CeO 2 relative to the matrix material.
The lead-free piezoelectric ceramic material according to claim 2, wherein said base material is doped with at least one of a component lanthanum and a component lanthanum, said component being extracted from strontium carbonate SrCO 3 The component is extracted from barium carbonate BaCO 3 .
The lead-free piezoelectric ceramic material according to claim 6, wherein a part of Na + in the base material is substituted with at least one of Sr 2+ and Ba 2+ .
The lead-free piezoelectric ceramic material according to claim 3, which has a molecular formula of: Na 0.5 Bi 4.5 Ti 4 O 15 + x mol% Nb 2 O 5 + y wt % CeO 2 , wherein 0 < x ≤ 7, 0 <y ≤ 2.
The lead-free piezoelectric ceramic material according to claim 7, which has a molecular formula of: (Na 0.5-z- w Sr z Ba w )Bi 4.5 Ti 4 O 15 +x mol% Nb 2 O 5 +y wt%CeO 2 Where 0<x≤7, 0<y≤2, 0<z<0.5, 0<w<0.5, 0<z+w<0.5.
A lead-free piezoelectric element comprising the lead-free piezoelectric ceramic material according to any one of claims 1-9.