JP2010126421A - Ceramics production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for production of lead-free piezoelectric ceramics which uses a metal oxide and carbonate as starting materials, employs a solid-phase reaction method, is inexpensive in production cost compared with a gas-phase reaction method and is simple and easy to carry out a process. <P>SOLUTION: The production method for the ceramic having a chemical composition represented by x[(Bi<SB>a</SB>K<SB>1-a</SB>)TiO<SB>3</SB>]-(1-x)[BiFeO<SB>3</SB>] (wherein 0.5≤x≤0.6 and 0.4<a<0.6) includes the processes of: preparing the metal oxide and carbonate as starting materials; obtaining the mixture thereof; obtaining a molded body including the mixture; and heat-treating the molded body. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing ceramics.

For example, ceramic powder materials having piezoelectric characteristics (hereinafter referred to as “ceramic materials”) are used in various industrial fields as materials for piezoelectric elements. A piezoelectric element is used as an actuator that converts an electrical signal into physical power because it deforms when a voltage is applied. For example, in a liquid ejecting apparatus using ink jet technology, an actuator using a piezoelectric element is used as a pressure actuator for ejecting ink regardless of whether it is for home use or industrial use. The piezoelectric ceramic material used as the material of the piezoelectric element is represented by lead zirconate titanate (composition formula Pb (Zr _1-X Ti _X ) O ₃ containing lead as a main component from the viewpoint of excellent piezoelectric characteristics, The abbreviation “PZT” has been used most widely. However, when the piezoelectric element contains lead, environmental considerations are necessary. In particular, in recent years, starting with the response to the EU's ROHS directive, lead regulations are spreading all over the world, so lead-free alternative piezoelectrics that do not contain lead and have the same piezoelectric properties as PZT systems Development of ceramic materials is required.

An example of a lead-free piezoelectric ceramic material, chemical composition _{x [(Bi a K 1-} a) TiO 3] - (1-x) [BiFeO 3] ( where, 0.5 ≦ x ≦ 0.6, 0 And piezoelectric ceramic material represented by 4 <a <0.6). In the following, the ceramic material, BKT the _{[(Bi a K 1-a} ) TiO 3], and abbreviated as BFO the [BiFeO _3], and BKT-BFO based piezoelectric ceramic. The BKT-BFO-based piezoelectric ceramic material is a piezoelectric ceramic that does not contain lead, and has excellent piezoelectric characteristics and dielectric characteristics, and is therefore a promising alternative piezoelectric ceramic material for PZT-based piezoelectric ceramic materials. However, in the manufacturing method, since Bi and K have high volatility and the Fe valence of BFO is unstable, a high-density single crystal phase BKT-BFO piezoelectric ceramic material is used. Difficult to get.

  Regarding the production method, for example, Patent Document 1 discloses a technique using an organic compound such as a 2-ethylhexanoic acid complex which is a metal salt as a starting material. Specifically, regarding the manufacturing process, an organic compound such as a 2-ethylhexanoic acid complex is vaporized by a gas phase reaction method, cooled, a raw material powder is obtained, a raw material powder is formed, and heat treatment is performed at a predetermined temperature. A manufacturing method is described in which a BKT-BFO based piezoelectric ceramic material is obtained.

However, in the method disclosed in Patent Document 1, an expensive metal salt is used as a starting material. In addition, the manufacturing process is complicated because the vapor phase reaction method is used in the process of manufacturing the piezoelectric ceramic material from the starting material.
JP 2008-069051 A

  One of the objects of the present invention is to provide a method for producing a BKT-BFO-based piezoelectric ceramic material using an inexpensive starting material.

  Another object of the present invention is to provide a method for producing a BKT-BFO-based piezoelectric ceramic material that uses a solid-phase reaction method and does not require a gas-phase reaction method, and has a simpler production process. There is.

The method for producing a ceramic according to the present invention comprises:
In _{(1-x) [BiFeO 3} ] ( where, 0.5 ≦ x ≦ 0.6,0.4 <a <0.6) - chemical composition _{x [(Bi a K 1-} a) TiO 3] A method for producing ceramics represented by:
Preparing a metal oxide and carbonate as starting materials;
Obtaining a mixture comprising the metal oxide and the carbonate;
Obtaining a shaped body containing the mixture,
Firing the molded body.

  According to the method for producing a ceramic according to the present invention, a BKT-BFO based piezoelectric ceramic can be produced using a metal oxide and a carbonate as starting materials.

In the method for producing a ceramic according to the present invention, the metal oxide may be Bi ₂ O ₃ , Fe ₂ O ₃ , and TiO ₂ , and the carbonate may be K ₂ CO ₃ .

  In the method for producing a ceramic according to the present invention, the step of obtaining the mixture can be performed using a physical pulverization method.

  In the method for producing ceramics according to the present invention, after the step of obtaining the mixture, a step of pre-baking the obtained mixture at a temperature of 700 ° C. to 850 ° C. can be further included.

  In the method for producing a ceramic according to the present invention, the step of obtaining the formed body may include a step of mixing an organic component with the mixture and obtaining a formed body using the mixture.

In the method for producing a ceramic according to the present invention, the step of firing the molded body includes a binder removal step of removing the organic component contained in the molded body,
After the said process, the said molded object is baked and the process of obtaining ceramics can be included.

  In the method for producing a ceramic according to the present invention, the step of firing the molded body can be performed in an atmosphere containing bismuth and potassium.

  In the method for producing a ceramic according to the present invention, the step of firing the molded body may be performed in a state where the molded body is covered with the mixture.

  In the method for producing a ceramic according to the present invention, a firing temperature for firing the molded body is lower than a melting point temperature determined by a composition ratio of the chemical composition and higher than a temperature lower by 50 ° C. than the melting point temperature. it can.

  In the method for producing a ceramic according to the present invention, a firing temperature for firing the molded body is less than a melting point temperature determined by a composition ratio of the chemical composition and higher than a temperature lower by 45 ° C. than the melting point temperature. it can.

  In the method for producing a ceramic according to the present invention, the ceramic obtained after the step of firing the molded body may be a single crystal phase.

  Hereinafter, an embodiment suitable for the present invention will be described with reference to the drawings.

The method for manufacturing ceramics according to the present embodiment is as follows.
In _{(1-x) [BiFeO 3} ] ( where, 0.5 ≦ x ≦ 0.6,0.4 <a <0.6) - chemical composition _{x [(Bi a K 1-} a) TiO 3] A method for producing ceramics represented by:
Preparing a metal oxide and carbonate as starting materials;
Obtaining a mixture comprising the metal oxide and the carbonate;
Obtaining a shaped body containing the mixture,
Heat-treating the molded body.

  FIG. 1 is a diagram showing a process of a ceramic manufacturing method according to the present embodiment. Below, each process of the manufacturing method of the ceramics concerning this embodiment is demonstrated, referring FIG.

1. Step of preparing starting material (S1)
First, as shown in FIG. 1, a metal oxide and a carbonate which are starting materials for the ceramic manufacturing method according to the present embodiment are prepared. In the present embodiment, bismuth oxide (Bi ₂ O ₃ ), iron oxide (Fe ₂ O ₃ ), and titanium oxide (TiO ₂ ) can be used as the metal oxide. Further, potassium carbonate (K ₂ CO ₃ ) can be used as the carbonate. These raw materials are respectively added in predetermined amounts so that [(Bi _0.5 K _0.5 ) TiO ₃ ]: [BiFeO ₃ ] has a molar ratio of 60:40 to 50:50. Weigh.

2. Step of obtaining a mixture (S2)
Next, a mixture which is a raw material powder is prepared using the weighed starting materials. As a method for preparing the mixture, a known physical pulverization method can be used. By using a known physical pulverization, the particle size can be adjusted to a desired particle size. Specifically, a dry pulverization method and wet pulverization such as a bead mill, a sand mill, an attritor, a ball mill, and a jet mill can be used as appropriate. Preferably, wet pulverization that prevents oxidation and enables atomization can be used. When wet pulverization is performed with a ball mill, the starting materials after weighing are bismuth oxide (Bi ₂ O ₃ ), iron oxide (Fe ₂ O ₃ ), titanium oxide (TiO ₂ ), and potassium carbonate (K _2). CO ₃ ) is mixed with the dispersion medium and charged into the pulverizer. As the dispersion medium, water, methanol, ethanol, propanol, butanol, acetone, benzene, cyclohexane, or toluene can be used. Furthermore, pulverization media such as zirconia balls can be added to the pulverizer, and mixing and pulverization can be performed until the particle size of the starting material is fine and uniform. Thereby, the raw material powder whose particle size of a mixture is a nanometer level fine structure and is a uniform composition can be produced (S2-1).

  Next, the dispersion medium can be dried and removed by removing pulverized media such as zirconia balls and performing heat treatment. Thereby, the mixture which consists of raw material powder of the ceramics concerning this embodiment can be obtained (S2-2).

  In addition, you may perform temporary baking with respect to the obtained mixture here. You may perform the temperature of temporary baking at the temperature of 700 to 850 degreeC, for example (S2-3). Thereby, the composition of the mixture can be made uniform and the strength of the ceramic after firing can be increased. However, this temporary firing is not necessarily required, and the raw material powder from which the dispersion medium has been removed by drying may be used as the mixture according to the present embodiment.

3. Step of obtaining a molded body (S3)
A suitable organic component binder (binder), a plasticizer, an organic solvent (dispersant), etc. are added and mixed with the obtained mixture, and slurry is produced (S3-1). For example, it is preferable to wet pulverize a mixture to which an organic component binder or the like is added. Here, as an organic component binder, polyvinyl alcohol (PVA), polyvinyl butyral (PVB), etc. are used suitably, for example.

  Next, the mixture of the organic component and the ceramic powder can be obtained by drying the slurry.

  Next, the obtained mixture of organic component and ceramic powder can be formed into a desired shape using a known press machine, doctor blade, reverse coater, or the like (S3-2). The shape of the molded body is not particularly limited, and may be appropriately determined according to the use of the piezoelectric ceramic to be produced. For example, using a known press machine, a mixture of an organic component and a ceramic powder can be formed into a cylindrical pellet having a diameter of about 10 mm and a thickness of about 1 mm. Thereby, the molded object which concerns on this embodiment can be obtained.

4). Heat-treating the molded body (S4)
The heat treatment process according to the present embodiment can be performed using, for example, an electric furnace.

  First, the said molded object is heat-processed and the organic component added at the time of slurry preparation is removed (S4-1, binder removal process). Here, the temperature of the heat treatment may be set to 600 to 800 ° C., for example, as long as the organic component can be sufficiently removed. Since the binder removal treatment involves oxidative decomposition of organic matter, for example, heat treatment is performed using an open system.

  Next, the molded body from which the organic component has been removed is fired (S4-2). Here, the firing step of firing the molded body can be performed by a closed system apparatus. For example, it can be performed inside sealed with a sheath of magnesia or the like.

  The reason for this is as follows. FIG. 2 shows a differential thermal curve (DTA curve) which is a measurement result of differential thermal and thermogravimetric measurement TG (Differential Thermal Analysis) at a composition ratio of BKT: BFO (60:40), and thermal weight. It is a figure which shows a curve (TG curve). The measuring apparatus used was BRUKER, TG-DTA2000SA. The measurement was performed in an open system on a platinum pan, and the measurement conditions were measured in air at a heating rate of 10 ° C./min. As shown in FIG. 2, it can be confirmed from the result of the TG curve that the weight reduction is 0.6% between 1000 ° C. and 1200 ° C., which is the firing temperature. This weight loss is the volatilization of bismuth and potassium, which have a lower vapor pressure than the other components. This shows that in an open system, bismuth and potassium are volatilized between 1000 ° C. and 1200 ° C., which is the firing temperature. Therefore, by performing the firing step in a closed system, it is possible to reduce the diffusion of bismuth and potassium, which are volatilized from the molded body, into the atmosphere, and to reduce the composition deviation and the density of the molded body. it can.

  Furthermore, the firing process is performed in a sealed atmosphere containing bismuth and potassium. For example, in the above-mentioned closed system apparatus, the mixture obtained by the step (S2) of obtaining the mixture described above is used while sufficiently covering the molded body to be fired. As a result, the firing atmosphere around the compact during firing can be a bismuth and potassium atmosphere that has volatilized from the mixture. As a result, it is possible to reduce bismuth and potassium from volatilizing and diffusing into the atmosphere from the molded body.

  The firing temperature is determined by the composition ratio of the chemical composition of the molded body to be fired. Specifically, the firing temperature for firing the compact is determined by the melting point temperature that varies depending on the composition ratio of BKT: BFO. Details of the relationship between the composition ratio and the melting point temperature will be described later.

  In the present embodiment, the firing temperature for firing the molded body can be set to a temperature lower than the melting point temperature and higher than a temperature that is 50 ° C. lower than the melting point temperature.

  More preferably, the firing temperature for firing the molded body can be set to a temperature lower than the melting point temperature and higher than 45 ° C. lower than the melting point temperature.

  The firing time can be, for example, 2 hours to 12 hours. By firing the compact at the firing temperature described above, it is possible to obtain a densified, uniform and high-density ceramic.

  The ceramic manufacturing method according to the present embodiment has, for example, the following characteristics.

According to the process for manufacturing the ceramic according to the present embodiment, the chemical composition _{x [(Bi a K 1-} a) TiO 3] - (1-x) [BiFeO 3] ( where, 0.5 ≦ x ≦ 0. In order to produce ceramics represented by 6,0.4 <a <0.6), bismuth oxide (Bi ₂ O ₃ ), iron oxide (Fe ₂ O ₃ ), titanium oxide (TiO ₂ ), and carbonic acid Potassium (K ₂ CO ₃ ) can be used as a starting material. Thereby, an inexpensive raw material can be used and a manufacturing cost can be reduced.

According to the process for manufacturing the ceramic according to the present embodiment, by using the solid-phase reaction method, chemical composition _{x [(Bi a K 1-} a) TiO 3] - (1-x) [BiFeO 3] ( provided that , 0.5 ≦ x ≦ 0.6, 0.4 <a <0.6) can be produced. Thus, an apparatus used for the gas phase reaction method is not required, and it can be manufactured by a simple process.

  According to the method for producing a ceramic according to the present embodiment, in the firing step, the molded body can be fired in an atmosphere containing bismuth and potassium. Thereby, it is possible to suppress the volatilization and diffusion of bismuth and potassium in the firing step, and a dense ceramic can be obtained.

According to the method for producing a ceramic according to the present embodiment, in the firing step, the firing temperature can be set to a temperature lower than the melting point temperature and higher than a temperature lower by 50 ° C. than the melting point temperature. More preferably, the firing temperature for firing the molded body can be set to a temperature lower than the melting point temperature and higher than 45 ° C. lower than the melting point temperature. Thereby, generation | occurrence | production of a hole can be suppressed in the ceramic surface and a precise | minute ceramic can be obtained. That is, a uniform and high-density ceramic can be obtained. Details will be described later.

5). FIG. 3 shows a DTA curve (FIG. 3A) when the composition ratio of BKT: BFO is changed to 30:70, 40:60, and 60:40, and for each BFO. It is a figure which shows melting | fusing point temperature distribution in a ratio (FIG.3 (b)). Below, the determination method of the calcination temperature which concerns on this embodiment is demonstrated, referring FIG. The temperature at the start of melting corresponds to a temperature at which a significant change in inclination is observed in the differential heat curve of FIG. The melting point temperature is in the vicinity of the minimum point of the DTA curve and is determined by the tangent line of the DTA curve.

As described above, the firing temperature for firing the molded body according to this embodiment is determined by the melting point temperature of the molded body. As described above, in the mixture according to this embodiment, [(Bi _0.5 K _0.5 ) TiO ₃ ]: [BiFeO ₃ ] has a composition ratio of 60:40 to 50:50 in terms of mol%. The melting point temperature is determined by the respective composition ratios. As shown in FIG. 2, the melting point temperature at the composition ratio of BKT: BFO (60:40) has a clear exothermic peak near 1095 ° C., and therefore there is a melting point temperature in this temperature range. You can see that As shown in FIG. 3 (a), when the composition ratio of BKT: BFO is changed to 30:70, 40:60, and 60:40, the peak of the drop in heat generation is lowered, and FIG. 3 (b) As can be seen from the graph, as the proportion of BFO increases, the melting point temperature decreases. By the above method, in this embodiment, the melting point temperatures of BKT: BFO (60:40) and BKT: BFO (50:50) can be determined to be 1095 ° C. and 1085 ° C., respectively. The range of the firing temperature according to the present embodiment can be determined by the melting point temperature obtained as described above. Specifically, when the melting point temperature is Tm and the firing temperature is T, the melting point temperature Tm and the firing temperature T according to the present embodiment satisfy the relational expression (Tm−50) <T <Tm. More preferably, the melting point temperature Tm and the firing temperature T according to this embodiment satisfy the relational expression (Tm−45) <T <Tm.

  The ceramic according to the present embodiment can be obtained through the above steps.

  The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same purposes and effects). In addition, the present invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that achieves the same effect as the configuration described in the embodiment or a configuration that can achieve the same object. Further, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

  Embodiments of the present invention will be described below with reference to the drawings.

In Example 1, a ceramic having a composition ratio of BKT: BFO (60:40) was produced using the ceramic production method according to this embodiment, and the characteristics thereof were evaluated. In Example 2, ceramics having a composition ratio of BKTB: FO (50:50) were produced using the ceramic production method according to this embodiment, and the characteristics were evaluated. For the purpose of evaluating the characteristics, the pellet-shaped ceramic obtained after the firing step is polished to a thickness of 0.5 to 0.8 mm, for example, and then an electrode is applied by a known method such as sputtering or screen printing. did. Ag was used as the electrode material. After applying Ag, the electrode was baked at a temperature of 700 ° C. The polarization treatment was performed by applying an electric field of 5 kVmm ⁻¹ for about 3 minutes in silicon oil. For evaluation of characteristics, PE hysteresis was measured at a frequency of 10 Hz and room temperature, and remanent polarization Pr and coercive electric field Ec were obtained.

  Regarding the relative density of the ceramics after firing, it is currently confirmed whether the raw material powder (mixture) of the BKT-BFO piezoelectric ceramic is a solid solution, a composite, or a mixture of these. The theoretical density cannot be calculated. Therefore, in this example, the density of the ceramic was evaluated by the SEM image of the surface.

Example 1
1. Firing conditions The firing temperature of the ceramic having a composition ratio of BKT: BFO (60:40) is less than 1095 ° C. because the melting point temperature is 1095 ° C. from the result of the DTA curve in FIG. It can be set to a temperature higher than 1045 ° C., which is a temperature lower by 50 ° C. More preferably, it can be set to a temperature higher than 1050 ° C., which is lower than 1095 ° C. and 45 ° C. lower than 1095 ° C. Specifically, the firing was performed at 1050 ° C. and 1060 ° C. As a comparative example, it was also carried out at firing temperatures of 1000 ° C., 1080 ° C., and 1100 ° C.

2. Surface State FIG. 4 shows an SEM image of the ceramic surface after firing. 4A is an SEM image of a ceramic fired under a firing condition of 1050 ° C. (2 hours), and FIG. 4B is an SEM image of a ceramic fired under a firing condition of 1060 ° C. (2 hours). is there. According to this, many holes are confirmed on the ceramic surface fired at 1050 ° C. On the other hand, almost no holes are observed on the ceramic surface fired at 1060 ° C., and it can be confirmed that the ceramic is densified.

  Table 1 shows the ceramic surface state after firing at the firing temperature at each temperature in this example. According to this, it can be seen that the surface of the ceramic fired at 1060 ° C. is densified without generating holes. However, as the temperature difference between the melting point temperature and the firing temperature increases, the number of holes generated on the surface increases, and it becomes impossible to obtain a dense and uniform ceramic. That is, it can be seen that the ceramic fired at 1060 ° C. is the highest density ceramic.

3. Crystal Structure FIG. 5 shows an X-ray diffraction pattern of a ceramic having a composition ratio of BKT: BFO (60:40) fired at 1060 ° C. Although three patterns are shown in FIG. 5, the calcining temperature of the molded body is the same condition at 1060 ° C., whereas the calcining temperature when calcining is performed in the step of forming the mixture. The conditions are 700 ° C. and 850 ° C., and the conditions for the firing time are 2 hours and 12 hours.

  According to FIG. 5, it can be seen that the crystal structure of the ceramic fired at 1060 ° C. is a single phase with good crystallinity, regardless of temporary firing or firing time.

4). PE Hysteresis FIG. 6 shows the PE hysteresis of ceramics having a composition ratio of BKT: BFO (60:40) fired at 1060 ° C. As shown in FIG. 6, it can be seen that the ceramic according to Example 1 has sufficient piezoelectric characteristics. From this hysteresis, it is understood that the residual polarization Pr of the ceramic according to Example 1 is 6.0 pCcm ⁻² and the coercive electric field Ec is 1.4 kVmm ⁻¹ .

(Example 2)
1. Firing Conditions The firing temperature of ceramics having a composition ratio of BKT: BFO (50:50) can be obtained from the result of the DTA curve in the same manner as in Example 1, and the melting point temperature is 1085 ° C. Therefore, the firing temperature can be set to a temperature higher than 1035 ° C., which is lower than 1085 ° C. and 50 ° C. lower than 1085 ° C. More preferably, the firing temperature can be set to a temperature higher than 1040 ° C., which is lower than 1085 ° C. and 45 ° C. lower than 1085 ° C. Specifically, it was carried out at a firing temperature of 1050 ° C.

2. Surface condition Although not shown in the figure, it is confirmed that there are almost no holes on the ceramic surface obtained by firing a ceramic having a composition ratio of BKT: BFO (50:50) at 1050 ° C., and the ceramic is dense. It was.

3. Crystal structure Although not shown, it was confirmed that the crystal structure of a ceramic obtained by firing ceramics having a composition ratio of BKT: BFO (50:50) at 1050 ° C. is a single phase with good crystallinity.

4). PE Hysteresis FIG. 7 shows the PE hysteresis of a ceramic having a composition ratio of BKT: BFO (50:50) fired at 1050 ° C. As shown in FIG. 7, it can be seen that the ceramic according to Example 2 has sufficient piezoelectric characteristics. From this hysteresis, it can be seen that the residual polarization Pr of the ceramic according to Example 1 is 10.4 pCcm ⁻² , and the coercive electric field Ec is 2.3 kVmm ⁻¹ .

The figure which shows the manufacturing method of the ceramics which concern on this embodiment. The figure which shows the TG-DTA measurement result of the ceramics based on Example 1. FIG. The figure which shows the relationship between the ratio of the composition ratio of the ceramic concerning this embodiment, and melting | fusing point temperature. 1 is an electron micrograph of ceramics according to Example 1. 2 is an X-ray diffraction pattern of ceramics according to Example 1. FIG. 2 shows a PE hysteresis of the ceramic according to Example 1. FIG. The PE hysteresis of the ceramics concerning Example 2. FIG.

Claims (11)

In _{(1-x) [BiFeO 3} ] ( where, 0.5 ≦ x ≦ 0.6,0.4 <a <0.6) - chemical composition _{x [(Bi a K 1-} a) TiO 3] A method for producing ceramics represented by:
Preparing a metal oxide and carbonate as starting materials;
Obtaining a mixture comprising the metal oxide and the carbonate;
Obtaining a shaped body containing the mixture,
Firing the molded body;
A method for producing ceramics comprising: In claim 1,
The metal _{oxide, Bi 2 O 3, Fe 2} O 3, and a TiO _2, the carbonate _is K 2 CO _3, method of manufacturing a ceramic. In claim 1 or 2,
The step of obtaining the mixture is a method for producing ceramics, which is performed using a physical pulverization method. In any one of Claims 1 thru | or 3,
A method for producing ceramics, wherein, after the step of obtaining the mixture, a step of further calcining the obtained mixture at a temperature of 700 ° C. to 850 ° C. is performed. In any one of Claims 1 thru | or 4,
The step of obtaining the molded body includes a step of mixing an organic component with the mixture and obtaining a molded body using the mixture.
A method for producing ceramics comprising: In any one of Claims 1 thru | or 5,
The step of firing the molded body includes a binder removal step of removing the organic component contained in the molded body,
After the step, firing the molded body to obtain ceramics;
A method for producing ceramics comprising: In claim 6,
The step of firing the molded body is a method for producing ceramics, which is performed in an atmosphere containing bismuth and potassium. In claim 6,
The step of firing the shaped body is a method for producing ceramics, wherein the shaped body is covered with the mixture. In any one of claims 6 to 8,
The method for producing ceramics, wherein a firing temperature for firing the molded body is lower than a melting point temperature determined by a composition ratio of the chemical composition and higher than a temperature lower by 50 ° C. than the melting point temperature. In any one of claims 6 to 8,
The method for producing ceramics, wherein a firing temperature for firing the molded body is lower than a melting point temperature determined by a composition ratio of the chemical composition and higher than a temperature lower by 45 ° C. than the melting point temperature. In any one of Claims 1 thru | or 10,
The method for producing ceramics, wherein the ceramic obtained after the step of firing the molded body is a single crystal phase.