KR20240086968A - Piezoelectric ceramic sintering jig and piezoelectric ceramic sintering unit including the same - Google Patents

Abstract

The present invention relates to a piezoelectric ceramic sintering jig. The present invention is an embodiment of a first setter that is open on one side and has a space inside, a second setter that is made of a plate shape, is disposed in the inner space of the first setter, contains a PbO component, and has a piezoelectric ceramic sheet placed on the top. , a spacer made of a rod shape with a certain length and arranged at intervals along the edge of the second setter, and a third setter placed on the spacer, containing a PbO component, and covering the top of the piezoelectric ceramic sheet. A piezoelectric ceramic sintering jig and a sintering unit including the same are presented.

Description

Piezoelectric ceramic sintering jig and piezoelectric ceramic sintering unit including the same {Piezoelectric ceramic sintering jig and piezoelectric ceramic sintering unit including the same}

The present invention relates to a piezoelectric ceramic sintering jig and a piezoelectric ceramic sintering jig that can prevent shrinkage of piezoelectric ceramics by suppressing the emission of plastic gas and a piezoelectric ceramic sintering unit including the same.

In general, a piezoelectric element is an element that generates voltage when vibration is applied and mechanical deformation occurs when voltage is applied. It is capable of converting mechanical vibration energy into electrical energy and electrical energy into mechanical vibration energy. It is known to be a very efficient device.

Accordingly, piezoelectric elements can be used as acceleration sensors, etc. by using the principle of converting vibration into electrical energy, or by using the principle of converting electrical energy into sound in the audible range, they can be used to pick up record discs, etc. It is used in devices such as microphones, speakers, and buzzers.

As a material used as a piezoelectric material for a piezoelectric speaker, ceramic, which is easy to manufacture and inexpensive, is mainly used, and it is generally manufactured by firing raw material powder, forming it into a plate shape, and then charging it into a sintering unit and sintering.

However, during the sintering process, volatile substances contained in the ceramic are released as plastic gas, which may change the composition and cause warping of the sintered ceramic, so a method to properly control this is needed.

Republic of Korea Patent Publication No. 10-2018-0013028 (2018.02.07)

The present invention can produce piezoelectric ceramics made of a single layer of a certain thickness at high density without warping, thereby ensuring the reliability and performance of the device, and is also suitable for mass production of large-area piezoelectric ceramics, and simplifies the process and improves productivity. A piezoelectric ceramic sintering jig that can be improved is presented. Additionally, a piezoelectric ceramic sintering unit including this is presented.

Other detailed purposes of the present invention will be clearly understood and understood by experts or researchers in this technical field through the detailed contents described below.

In order to solve the above problem, the present invention is an embodiment, a first setter that is open on one side and has a space inside, is made of a plate shape, is disposed in the inner space of the first setter, contains a PbO component, and has a piezoelectric ceramic on the top. A second setter on which the sheet is placed, a spacer made of a rod shape with a certain length and a plurality of spacers arranged at intervals along the edge of the second setter, and a top of the piezoelectric ceramic sheet placed on the spacer and containing a PbO component. A piezoelectric ceramic sintering jig including a third setter covering is presented.

At this time, the first setter may be made of a material containing ZrO ₂ component.

Additionally, the spacer may include a pair of first spacers arranged in parallel in the horizontal direction and a second spacer arranged in parallel in a vertical direction, and the vertex portion of the piezoelectric ceramic sheet may be open.

In order to solve the above problem, the present invention, as an embodiment, includes a shelf plate forming a floor, a support plate including a support plate and legs for supporting the support plate and placed on the shelf plate, and any of claims 1 to 4 placed on the support plate. A piezoelectric ceramic sintering unit is provided, including the piezoelectric ceramic sintering jig according to one item, the support, and a cover that covers and seals the piezoelectric ceramic sintering jig.

At this time, two supports are stacked to form two stages, and the piezoelectric ceramic sintering jig can be placed on each support.

According to an embodiment of the present invention, a piezoelectric ceramic sheet is placed between the first setter and the second setter containing the PbO component, and a spacer is used to secure a space for the piezoelectric ceramic sheet to be placed and at the same time suppress the emission of plastic gas.

In addition, a plurality of spacers are placed at intervals to form a space where some of the plasticized gas can be released, thereby discharging the binder component contained in the plasticized gas, while the PbO component contained in the first and second setters creates a space where the piezoelectric ceramic can be released. By suppressing the volatilization of the PbO component, piezoelectric ceramics consisting of a single layer of a certain thickness can be produced at high density without warping.

Other effects of the present invention will be readily apparent and understood by experts or researchers in the technical field through the specific details described below or during the process of implementing the present invention.

Figure 1 is a perspective view showing a piezoelectric ceramic sintering jig according to an embodiment of the present invention.
Figure 2 is an exploded perspective view showing the piezoelectric ceramic sintering jig according to the embodiment shown in Figure 1.
Figure 3 is a side view showing a piezoelectric ceramic sintering jig according to the embodiment shown in Figure 1.
Figure 4 is a conceptual diagram showing a piezoelectric ceramic sintering unit including a piezoelectric ceramic sintering jig according to an embodiment of the present invention.
Figure 5 is a view showing a piezoelectric ceramic sintering unit according to examples and comparative examples.
Figure 6 is a graph comparing the sound pressure characteristics of a piezoelectric speaker using a piezoelectric ceramic sintered body manufactured through a piezoelectric ceramic sintering unit according to Examples and Comparative Examples.

The features and effects of the present invention described above will become more apparent through the following detailed description in conjunction with the accompanying drawings, and accordingly, those skilled in the art will be able to easily implement the technical idea of the present invention. You will be able to. Since the present invention can be subject to various changes and can have various forms, specific embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention. The terms used in this application are only used to describe specific embodiments and are not intended to limit the invention.

Hereinafter, a piezoelectric ceramic sintering jig and a piezoelectric ceramic sintering unit including the same according to an embodiment of the present invention will be described in detail with reference to the drawings. In this specification, similar reference numbers are assigned to identical and similar configurations even in different embodiments, and the description is replaced with the first description.

Figure 1 is a perspective view showing a piezoelectric ceramic sintering jig according to an embodiment of the present invention, Figure 2 is an exploded perspective view of the sintering jig, and Figure 3 is a side view of the sintering jig.

The piezoelectric ceramic sintering jig according to an embodiment of the present invention includes a first setter 10, a second setter 20, a spacer 30, and a third setter 40.

The first setter is open on one side and has a space inside, and the second setter is placed in the space inside the first setter. The second setter is shaped like a plate and contains PbO, and a piezoelectric ceramic sheet is placed on the top.

Meanwhile, a plurality of spacers made of a rod shape with a certain length are arranged at intervals along the edge of the second setter. Additionally, a third setter is placed on the spacer. The third setter is placed by the spacer to cover the upper part of the piezoelectric ceramic sheet (S) while being spaced apart from the piezoelectric ceramic sheet (S) to a certain degree. The third setter is also made to contain a PbO component.

The piezoelectric ceramic sintering jig made in this way can release a part of the plastic gas in the gap between the plurality of spacers, while suppressing the volatilization of the PbO component in the piezoelectric ceramic as the PbO component of the second and third setters volatilizes. Therefore, the shrinkage rate can be controlled while suppressing the release of plastic gas to a certain extent. Accordingly, bending that may occur at the edges of the sintered body can be suppressed.

Hereinafter, each part will be described in detail with reference to the drawings.

The first setter 10 is open on one side and has a space inside, and the remaining components, including the second setter, spacer, and third setter, are arranged in the inside space. A piezoelectric ceramic sheet (S) is disposed between the second setter and the third setter.

Here, the piezoelectric ceramic sheet may be produced by mixing and pulverizing ceramic powder, adding an organic solvent to the pulverized ceramic powder to form a slurry, and then tape casting the produced slurry. More specifically, the produced piezoelectric ceramic sheet may be After being cut to size, it may have gone through a binder removal process to remove the binder contained in the ceramic powder.

Meanwhile, the first setter may be made of ZrO ₂ material, and it is preferable to use a low-density ZrO ₂ plate. The first setter keeps the second setter thin and flat. At this time, by using a low-density ZrO ₂ plate, heat transfer properties or reactivity with the second setter can be lowered, so that the sintered body is not affected during sintering.

The second setter 20 is made of a plate shape and is placed in the internal space of the first setter, and a piezoelectric ceramic sheet is placed on the top.

The second setter may be made of the same volatile component as the volatile component contained in the piezoelectric ceramic sheet. Since PZT-based piezoelectric ceramics are generally used as piezoelectric ceramics, the second setter may contain a high-density PbO component.

By making the second setter the same volatile component contained in the piezoelectric ceramic sheet, it is possible to control the bending of the piezoelectric ceramic sheet during the sintering process and further to implement a large-area piezoelectric material.

Specifically, piezoelectric ceramics contain volatile substances, and if these substances volatilize during the sintering process, warping may occur in the piezoelectric ceramic sheet. However, the total amount of this volatilization tends to be determined in a certain space. By making the second setter the same volatile component as the piezoelectric ceramic sheet, volatilization also occurs in the second setter and the degree of volatilization of the piezoelectric ceramic can be relatively lowered, so the occurrence of warpage can be minimized even in the case of large-area piezoelectric ceramic. there is.

This is applicable when the piezoelectric ceramic has volatile components such as PbO, MgO, Na ₂ CO ₃ , K ₂ CO ₃ , etc.

The spacers 30 are made in the shape of a bar with a certain length, and a plurality of them are arranged at intervals along the edge of the second setter, so that the third setter, which will be described later, is arranged at a certain distance from the second setter. Additionally, according to this, a piezoelectric ceramic sheet may be placed in the space where the second setter and the third setter are spaced apart.

Here, the spacer may include a pair of first spacers arranged in parallel in the horizontal direction and a second spacer arranged in parallel in a vertical direction, and the first spacer and the second spacer are prevented from meeting each other so that the piezoelectric ceramic sheet is formed. It is made in a form where the vertex part is open.

The plastic gas (G) released from the piezoelectric ceramic sheet during sintering is released in a radial form. A space is formed in the open portion between the plurality of spacers where a portion of the plastic gas can be released, thereby enabling the release of a certain amount of plastic gas. .

If plastic gas remains between the second setter and the third setter, it may affect the center and edge portions of the sintered body, causing bending of the sintered body. In this way, by forming a space through which the plastic gas can be released using the spacer, it is possible to smoothly control the bending of the sintered body.

Meanwhile, like the second and third setters, the spacer may be made of a material containing PbO.

The third setter 40 is placed on the spacer and covers the top of the piezoelectric ceramic sheet. Accordingly, the second setter, spacer, and third setter surround the piezoelectric ceramic sheet. The third setter has substantially the same configuration as the second setter, and the description of the second setter can be applied as is.

Hereinafter, a piezoelectric ceramic sintering unit including a piezoelectric ceramic sintering jig according to an embodiment of the present invention will be described in detail with reference to the drawings. Figure 4 shows a conceptual diagram showing a piezoelectric ceramic sintering unit.

Referring to the drawing, the piezoelectric ceramic sintering unit 200 includes a shelf plate 50, a support 60, a sintering jig 100, and a cover 70.

The shelf plate of the sintering unit forms the bottom and may be made of alumina. A support plate is placed on the shelf plate, and the support plate 60 has a support plate 61 and legs 62 that support the support plate and is in the form of a table.

A sintering jig according to an embodiment of the present invention is placed on the support. As described above, the sintering jig includes a first setter (10), a second setter (20), a spacer (30), and a third setter (40), and a piezoelectric ceramic sheet is placed between the second setter and the third setter. It is placed.

In this state, the sintering unit is constructed by covering and sealing the support and the piezoelectric ceramic sintering jig with a cover. The cover serves to prevent plasticizing gas from being released outside the sintering unit.

Meanwhile, two supports are stacked to form two stages, a piezoelectric ceramic sintering jig can be placed on each support, and the supports may be composed of three or more stages.

In addition, PbO atmosphere powder (P) is placed in the alumina setter 80 on the boer plate, and the PbO contained in the setter is volatilized during sintering, thereby suppressing the volatilization of PbO contained in the piezoelectric ceramic sheet.

A piezoelectric ceramic sheet can be sintered in a sintering unit configured as described above.

Piezoelectric ceramic sheets can be manufactured by mixing and pulverizing ceramic powder, adding an organic solvent to the pulverized ceramic powder to form a slurry, then tape casting and cutting the prepared slurry, and such piezoelectric ceramic sheets can be sintered in a sintering jig.

The sintering process may be carried out by loading a piezoelectric ceramic sheet into a sintering jig, performing a degreasing process, and then performing a sintering process.

In the degreasing process, the temperature is gradually increased to degrease the solvent and binder within the piezoelectric ceramic sheet.

To degrease solvents, etc., the temperature can be raised to 300~400℃ at 0.3℃/min and heat treatment can be performed for approximately 12 hours. Afterwards, in order to degrease the binder, etc., the temperature can be raised to 500-600℃ at 0.7℃/min and heat treatment can be performed for approximately 2 hours.

In the sintering process, piezoelectric ceramics are sintered at high density. The temperature can be raised to 1,100~1,300℃ at 4.0℃/min and heat treatment can be performed for approximately 5 hours.

The sintering process was performed in the sintering unit according to the embodiment of the present invention and the sintering unit according to the comparative example, and the results were compared.

The sintering unit of the example is a sintering unit in which a piezoelectric ceramic sheet (S) is charged into a sintering jig consisting of a first setter, a second setter, a spacer, and a third setter according to the present invention (see FIG. 5C), and Comparative Example 1 is a sintering unit. A sintering unit in which a piezoelectric ceramic block (B) was placed on a sintering plate 90 configured as a first setter rather than a jig was used (see Figure 5a). Comparative Example 2 used a sintering unit in which a piezoelectric ceramic sheet (S) was placed on a sintering plate (90) configured as a first setter rather than a sintering jig (see FIG. 5b).

Here, the piezoelectric ceramic sheet (S) is manufactured by tape casting a piezoelectric ceramic slurry as described above, and the piezoelectric ceramic block (B) is formed by bulk sintering piezoelectric ceramic powder and then processing it to a certain thickness.

In the sintering loading method according to the example, supports were stacked in two stages, a sintering jig was placed on each support, and sintering was performed at 1,150°C for 5 periods to obtain a piezoelectric ceramic sintered body. In the sintering loading method according to Comparative Example 1, a piezoelectric ceramic block (B) was placed on a sintering plate and sintered at 1,220° C. for 10 hours to obtain a piezoelectric ceramic sintered body, and in the sintering loading method according to Comparative Example 2, a piezoelectric ceramic block (B) was placed on a sintering plate. (S) and sintered at 1,220°C for 10 hours to obtain a piezoelectric ceramic sintered body.

External electrodes were connected to the obtained sintered body and polarized to manufacture a piezoelectric element, and then a piezoelectric speaker was manufactured using this.

Below, the sound pressure characteristics of a piezoelectric speaker made of a piezoelectric element according to an example and a piezoelectric speaker made of a piezoelectric element according to a comparative example were compared. The initial piezoelectric characteristics of the piezoelectric speakers of the examples and comparative examples and the sound pressure characteristics after 125 hours, 300 hours, and 500 hours under high temperature and high humidity conditions of 50°C and 80% were measured and are shown in Table 1.

Referring to Table 1, it was found that Comparative Example 1, which sintered a piezoelectric ceramic block, required a higher sintering temperature and a longer holding time for overall sintering compared to Example and Comparative Example 2, which sintered a piezoelectric ceramic sheet.

Meanwhile, the example using the sintering jig not only had superior sound pressure characteristics compared to Comparative Example 1 without using the sintering jig, but also had superior sound pressure characteristics after sintering compared to Comparative Example 2. Also, there was no sound pressure difference even after driving at high temperature and high humidity (0dB).

Meanwhile, Figure 6 shows a graph comparing the sound pressure characteristics of the piezoelectric speaker manufactured using the sintered unit according to the Example and Comparative Example 1 and the sintered body manufactured through the sinter loading method. When referring to this, the piezoelectric according to the Example It can be confirmed that the speaker has excellent sound pressure characteristics after sintering compared to the piezoelectric speaker according to Comparative Example 1, and that there is no difference in sound pressure even after driving at high temperature and high humidity.

As described above, the piezoelectric ceramic sintering jig and the sintering unit including the same are not limited to the configuration and method of the above-described embodiments, and the above embodiments are all or part of each embodiment so that various modifications can be made. It may also be configured by selective combination.

Although the detailed description of the present invention described above has been described with reference to preferred embodiments of the present invention, those skilled in the art or those skilled in the art will understand the spirit of the present invention as described in the patent claims to be described later. It will be understood that the present invention can be modified and changed in various ways without departing from the technical scope.

10: 1st setter 20: 2nd setter 30: Spacer 40: 3rd setter
50: Shelf plate 60: Support plate 61: Support plate 62: Leg
70: Cover 80: Alumina Setter 90: Sintering Plate
S: Piezoelectric ceramic sheet B: Piezoelectric ceramic block P: Powder G: Plastic gas
100: Sintering jig 200: Sintering unit

Claims (5)

The first setter, which is open on one side and has space inside,
A second setter made of a plate shape and disposed in the interior space of the first setter, contains a PbO component, and has a piezoelectric ceramic sheet placed on the top,
A spacer made of a rod shape with a certain length and arranged in plural numbers at intervals along the edge of the second setter, and
A third setter placed on the spacer, containing a PbO component, and covering the top of the piezoelectric ceramic sheet.
A piezoelectric ceramic sintering jig containing a. According to paragraph 1,
The first setter is a piezoelectric ceramic sintering jig made of a material containing ZrO ₂ component. According to paragraph 1,
The spacer is,
It includes a pair of first spacers arranged in parallel in the horizontal direction and a pair of second spacers arranged in parallel in the vertical direction,
A piezoelectric ceramic sintering jig in which the apex of the piezoelectric ceramic sheet is opened. Shelf plates that make up the floor,
A support plate provided on the shelf plate and having legs for supporting the support plate,
A piezoelectric ceramic sintering jig according to any one of claims 1 to 4 placed on the support, and
A cover that covers and seals the support and the piezoelectric ceramic sintering jig.
A piezoelectric ceramic sintering unit comprising a. According to clause 4,
A piezoelectric ceramic sintering unit in which two supports are stacked to form two stages, and the piezoelectric ceramic sintering jig is placed on each support.

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