JP2007269504A - Method of controlling characteristics of sintered member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of controlling characteristics by which the demand characteristics of a sintered members are attained by adjusting to a composition required as the sintered member even when the shift of the composition occurs in a stage of a formed body. <P>SOLUTION: The method of controlling the characteristic of the sintered member is provided with a step for analyzing the composition of raw material powder in the formed body constituted of the raw material powder and a step for firing the formed body while bringing a characteristic adjuster containing at least one kind of an ingredient contained in the raw material powder contact with the formed body. The characteristic adjuster can be powder containing at least one kind of the ingredient contained in the raw material powder. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for adjusting the characteristics of a sintered member, and more particularly to a method for adjusting the characteristics of a sintered member after firing after forming a molded body.

Conventionally, as a resonator for obtaining an oscillation frequency, a piezoelectric resonant component (resonator) using a piezoelectric resonator is known. As shown in FIG. 1, the piezoelectric resonator 2 has a pair of vibrating electrodes 22 and 23 formed on the front and back main surfaces of a polarized piezoelectric ceramic substrate 21, and the pair of vibrating electrodes 22 and 23. It is configured so that vibration is confined in the vicinity. A resonator 1 using the piezoelectric resonator 2 includes a substrate 3 and a cap 5 as shown in FIG. The substrate 3 has a reinforcing function, and is made of ceramics such as steatite (MgO.SiO ₂ ) and alumina (Al ₂ O ₃ ), and usually has a thickness of about 0.05 to 0.7 mm. . Terminal electrodes 31 and 32 are formed on the front and back surfaces of the substrate 3. The substrate 3 may be configured to have both a dielectric function and a reinforcing function using dielectric single plate ceramics, laminated ceramics, or the like. Examples of the dielectric single plate ceramic include a compound mainly composed of barium titanate. Examples of laminated ceramics include low-temperature sintered ceramics with internal electrodes. For example, Al ₂ O ₃ or CaZrO ₃ added with glass components and Cu and Ag conductive pastes are simultaneously fired at 1000 ° C. or lower. You can get it.

On the terminal electrodes 31 and 32, the piezoelectric resonator 2 is bonded and fixed by a conductive stator 4 having both conductive and adhesive functions such as conductive resin and solder. A constant vibration space is secured between the piezoelectric resonator 2 and the substrate 3 by the thickness of the conductive stator 4.
The cap 5 is bonded to the substrate 3 with an adhesive, for example, so as to cover the piezoelectric resonator 2. The cap 5 can also be made of ceramics such as steatite (MgO.SiO ₂ ) and alumina (Al ₂ O ₃ ), like the substrate 3, but may be made of a metal such as an alloy. The plate thickness of the cap 5 is also approximately the same as that of the substrate 3.
The resonator 1 as described above is disclosed, for example, in JP-A-8-237066 (Patent Document 1).

JP-A-8-237066

The piezoelectric resonator 2 is usually composed of a piezoelectric ceramic having a perovskite structure such as a tetragonal or rhombohedral PZT (PbZrO ₃ —PbTiO ₃ solid solution) system or a PT (PbTiO ₃ ) system near room temperature. Yes. This piezoelectric ceramic can be obtained by mixing a predetermined piezoelectric ceramic powder with a binder to produce a molded body having a predetermined shape and firing the molded body. The piezoelectric ceramic powder is obtained by mixing a plurality of kinds of starting material powders, calcining them and then pulverizing them. The composition of the starting material powder is adjusted and blended in accordance with the characteristics desired to be obtained as the piezoelectric resonator 2.

However, the characteristics required by the piezoelectric ceramic obtained by firing the molded body may not be satisfied. In particular, in recent years when the range of required characteristics has become strict, the characteristics of piezoelectric ceramics may deviate from the required characteristics.
Therefore, in the present invention, even if a composition deviation occurs at the stage of the molded body, the characteristics of the sintered member that can be adjusted to the desired composition as the sintered member and obtain the required characteristics of the sintered member. The purpose is to provide an adjustment method.

  The present inventors investigated the reason why the piezoelectric ceramic after firing does not satisfy the required characteristics. As a result, it was found that even if the composition was adjusted at the starting raw material powder stage, the composition was shifted until a subsequent molded body was obtained, so that the fired piezoelectric ceramic did not satisfy the required characteristics. Therefore, the present inventors examined a method for correcting the compositional deviation, and when firing the molded body in which the compositional deviation occurred, the composition containing the element in which the compositional deviation occurred was brought into contact with the molded body. Was found to be effective. When the element diffuses into the compact (sintered body) during the firing process, the compositional deviation occurring in the compact is compensated to suppress or prevent the compositional deviation in the sintered compact.

The present invention based on the above knowledge includes a step of performing a composition analysis of the raw material powder in a molded body composed of the raw material powder, and a characteristic including at least one component included in the raw material powder based on the result of the composition analysis. And a step of firing the molded body in a state where the adjusting agent is in contact with the molded body.
In the method for adjusting the characteristics of the sintered member of the present invention, in the step of firing the molded body, when it is determined that the composition is less than the desired composition in the sintered member, the characteristic adjusting agent containing the component is brought into contact with the molded body. What is necessary is just to bake a molded object in the state.
Moreover, in the characteristic adjustment method of the sintered member of the present invention, it is advantageous that the characteristic adjusting agent is a powder containing at least one component included in the raw material powder. In order to diffuse the element in the firing process, a powdery property adjusting agent is preferable. This property adjusting agent is preferably applied to the molded body as a paste as a mixture with a binder. When the paste is used, it is easy to control the amount of the property adjusting agent brought into contact with the molded body.

Although characteristic adjusting method of the sintered member of the present invention is not questioned the material to be applied directed to a piezoelectric ceramic mainly composed of lead zirconate titanate having a perovskite structure, in which case, characteristics ZrO ₂ powder It can be a regulator.

According to the present invention, even when the composition is shifted from the desired composition at the stage of the molded body, the composition shift can be compensated and the characteristics of the sintered member can be adjusted to the required characteristics.
Here, in order to correct the composition deviation of the raw material powder, a powder for correcting the composition deviation can be added to the raw material powder. However, in this case, it becomes impossible to produce a molded body while determining the composition deviation, which hinders the continuity of production. In addition, after adding the powder for correcting the composition deviation, it is necessary to repeat the process of mixing these powders, resulting in a waste of process.
On the other hand, since the present invention can adjust the characteristics even of a molded body having a composition deviation, it inhibits the continuity of production compared to the case of adding a powder for correcting the composition deviation. Therefore, the process is not wasted as described above.

The present invention provides a molded article with a property adjusting agent containing at least one of the components contained in the raw material powder based on the results of the composition analysis of the raw material powder in the molded body composed of the raw material powder and the result of the composition analysis. And firing the molded body in a contacted state.
The raw material powder constituting the compact includes various forms.
For example, when a molded body is composed of a plurality of types of metal (including alloys) powders as raw material powder, the molded body may be configured of a single or a plurality of types of compound powders as raw material powders. The invention of the present application also includes the case where the molded body is constituted by using metal powder and compound powder as raw material powder.
When the compound powder is a raw material powder constituting a molded body, the compound powder may be obtained by pulverizing a calcined body obtained by so-called calcining the starting material. In the case of a piezoelectric ceramic described later, the raw material powder constituting the compact is obtained by pulverizing a calcined body obtained by calcining the starting material.

Composition analysis is performed on the above raw material powder. In addition, the method of composition analysis is not limited in the present invention, and any known analysis method can be used, and may be appropriately selected according to the analysis target. The result of the composition analysis is compared with the target composition after sintering. For example, the sintered member is composed of element A, element B, and element C, and the aim of element A, element B, and element C is element A = x%, element B = y%, and element C = z%. On the other hand, if the result of the composition analysis is that the element A = x%, the element B = (y−y ₁ )%, and the element C = z%, a composition shift occurs with respect to the element B. . Therefore, when a molded body made of the raw material powder is sintered, composition deviation occurs also in the sintered body, and desired characteristics cannot be obtained. Regarding compositional deviation, even if there is a deviation, there is a permissible range, and even if the target composition after sintering and the result of composition analysis of the raw material powder do not match, it is considered that compositional deviation has occurred. Needless to say, there may be no need.

In the case of the above sintered member, element B is deficient from the target composition by y ₁ %. In this case, as a result of the composition analysis, a property adjusting agent containing element B corresponding to y ₁ % is prepared. This property adjusting agent usually has a powder form, and is fired in a state where the property adjusting agent is in contact with a formed body made of the raw material powder. As the property adjusting agent to be brought into contact with the molded product, the powder itself may be applied (sprayed) on the molded product, or the property adjusting agent may be mixed with a binder and applied as a paste to the molded product. When the property adjusting agent is contained in the paste, the amount of the property adjusting agent contained in the paste is specified, and when the element B is corrected by y ₁ % as described above, an equivalent amount of paste is added to the molded body. Apply. In addition, it is necessary to experimentally grasp in advance the amount of paste to be applied corresponding to the composition shift in element B. This applies not only to element B but also to element A and element C.

When the property modifier is brought into contact with the molded body, the molded body is fired. The present invention does not ask the firing conditions, and the firing may be performed under conditions according to the composition of the sintered body or raw material powder to be finally obtained. For example, the present invention can be applied to firing in various atmospheres such as firing in the air, firing in an atmosphere adjusted to be reducible or oxidizing. This also applies to the heating temperature, the rate of temperature increase or the temperature decrease in firing, and does not limit the present invention.
When the molded body includes a binder, firing is performed after removing the binder from the molded body. When the property adjusting agent is a paste, the binder can be removed from the paste at the same time. This binder removal can be performed by utilizing a heating process of baking.

Although the embodiments of the present invention have been conceptually described above, the present invention will be described more specifically by taking a method of manufacturing a piezoelectric ceramic as an example.
For example, the present invention can be applied to a piezoelectric ceramic mainly composed of PZT having the following composition formula and having a perovskite structure. This piezoelectric ceramic can contain, for example, one or more of Al ₂ O ₃ , SiO ₂ , MnCO ₃ and Cr ₂ O ₃ as subcomponents with respect to the main component.

Pb _α [(Mn _1/3 Nb _2/3 ) _x Ti _y Zr _z ] O ₃
In the composition formula, 0.97 ≦ α ≦ 1.01,
0.04 ≦ x ≦ 0.16,
0.48 ≦ y ≦ 0.58,
0.32 ≦ z ≦ 0.41.
In the composition formula, α, x, y, and z each represent a molar ratio.

As a starting material of the main component for obtaining the above piezoelectric ceramic, an oxide or a powder of a compound that becomes an oxide by heating is used. Specifically, PbO powder, TiO ₂ powder, ZrO ₂ powder, MnCO ₃ powder, Nb ₂ O ₅ powder, or the like can be used. Each raw material powder is weighed so as to correspond to the composition to be finally obtained. As a starting material, not an oxide but a material that becomes an oxide by firing, such as carbonate or oxalate, may be used. As these raw material powders, those having an average particle diameter of about 0.1 to 3 μm are usually used. When the piezoelectric ceramic contains subcomponents, a predetermined amount of subcomponent raw material powder is added to the total weight of each main component powder weighed.

Subsequently, the starting materials of the main component and the subcomponent are wet pulverized and mixed using, for example, a ball mill to obtain a raw material mixture.
In addition, although the starting material of a subcomponent may be added before temporary baking mentioned later, you may make it add after temporary baking. However, it is preferable to add it before calcination because a more uniform piezoelectric ceramic can be produced. When added after calcination, it is preferable to use an oxide as a starting material for the auxiliary component.

  Next, the raw material mixture is dried and, for example, calcined at a temperature of 700 to 950 ° C. for 0.5 to 6 hours. This pre-baking may be performed in the air, or may be performed in an atmosphere having a higher oxygen partial pressure or in a pure oxygen atmosphere than in the air. After calcining, for example, the calcined product is wet pulverized and mixed in a ball mill to obtain a calcined powder containing a main component and optional subcomponents. This temporarily fired powder corresponds to the raw material powder constituting the compact in the present invention.

Next, a composition analysis is performed on the temporarily fired powder. This composition analysis can be performed by fluorescent X-ray analysis or the like.
Here, for example, if the target composition after firing is the following composition, the result of composition analysis (the following analytical composition) is compared with the following target composition. As a result, it is found that the pre-fired powder has a composition shift with respect to Zr. If this compositional deviation is within the allowable range, there is no problem, but if it is outside the allowable range, a property adjusting agent is used. In this case, a property modifier for Zr is used.
Target composition: Pb _0.99 [(Mn _1/3 Nb _2/3 ) _0.10 Ti _0.53 Zr _0.37 ] O ₃
Analytical composition: Pb _0.99 [(Mn _1/3 Nb _2/3 ) _0.10 Ti _0.53 Zr _0.32 ] O ₃

In the case of the piezoelectric ceramic of the above composition formula, the characteristic adjusting agent is prepared in advance for each element of Pb, Mn, Nb, Ti and Zr. As the property adjusting agent, PbO powder for Pb, MnCO ₃ powder for Mn, Nb ₂ O ₅ powder for Nb, TiO ₂ powder for Ti, and ZrO ₂ powder for Zr can be used. These property modifiers are also starting material powders for each element. However, the property adjusting agent is not limited to the actually used starting material powder, but may be one that becomes the oxide by firing, such as carbonate or oxalate. For example, for Zr, the process of firing It is allowed to use metal Zr which becomes ZrO ₂ . When using powder as a characteristic modifier, the particle size is preferably 1 to 100 μm on average. This is because if the particle size is too small, the reaction proceeds too much and it becomes difficult to control, and conversely if the particle size is too large, there is a high possibility that the reaction will be uneven.

  When using the property adjusting agent as a paste, this paste is prepared in advance. The paste is prepared by adding a binder to a powdery property adjusting agent. Specifically, it is as follows. For example, a slurry containing the property adjusting agent is obtained by wet pulverization using a ball mill or the like. At this time, water or an alcohol such as ethanol or a mixed solvent of water and ethanol can be used as a solvent for the slurry. The resulting slurry is then dispersed in an organic vehicle. The organic vehicle is obtained by dissolving a binder in an organic solvent, and the binder used in the organic vehicle is not particularly limited, and may be appropriately selected from usual various binders such as ethyl cellulose, polyvinyl butyral, and acrylic. The organic solvent used at this time is not particularly limited, and may be appropriately selected from organic solvents such as terpineol, butyl carbitol, acetone, toluene, MEK (methyl ethyl ketone), and terpineol. This paste is prepared for each element of Pb, Mn, Nb, Ti and Zr.

  On the other hand, the calcined powder is granulated into granules in order to smoothly execute the subsequent molding process. At this time, a small amount of a suitable binder such as polyvinyl alcohol (PVA) is added to the pulverized powder, and these are mixed well, and then granulated by passing, for example, a mesh to obtain a granulated powder. Next, the granulated powder is pressure-molded at a pressure of 200 to 300 MPa to obtain a molded body having a desired shape.

After forming the molded body, a paste-like property adjusting agent is applied to the molded body. What is necessary is just to determine the quantity which apply | coats a paste to a molded object suitably according to a composition shift | offset | difference.
After applying the paste containing the property adjusting agent, a binder removal process is performed.
The binder removal process cannot be performed smoothly when the temperature of the binder removal process is less than 300 ° C., and even if the temperature exceeds 650 ° C., the effect of the binder removal corresponding to the temperature cannot be obtained, resulting in wasted energy. Therefore, it is preferable to carry out in the temperature range of 300-650 degreeC. The binder removal time needs to be determined depending on the temperature and atmosphere, but can be selected in the range of 0.5 to 50 hours. Further, the binder removal treatment can be performed independently of the firing and can be performed continuously with the firing. In the case where the firing is continuously performed, the binder removal process may be performed in the firing temperature increasing process.

Baking is performed after the binder removal treatment. Specifically, the compact is heated and held for a predetermined time within a range of 1100 to 1250 ° C. to obtain a sintered body. The atmosphere at this time may be N ₂ or air. The heating and holding time may be appropriately selected within the range of 0.5 to 4 hours.

After the electrode for polarization treatment is formed on the sintered body, the polarization treatment is performed. In the polarization treatment, an electric field of 1.0 to 2.0 Ec (Ec is a coercive electric field) is applied to the sintered body at a temperature of 50 to 300 ° C. for 0.5 to 30 minutes.
When the polarization treatment temperature is less than 50 ° C., Ec increases, so that the polarization voltage increases and polarization becomes difficult. On the other hand, when the polarization treatment temperature exceeds 300 ° C., the insulation of the insulating oil is remarkably lowered, so that polarization becomes difficult. Therefore, the polarization treatment temperature is 50 to 300 ° C. A preferable polarization treatment temperature is 60 to 250 ° C, and a more preferable polarization treatment temperature is 80 to 200 ° C.
Moreover, if the electric field to be applied is less than 1.0 Ec, polarization does not proceed. On the other hand, when the applied electric field exceeds 2.0 Ec, the actual voltage increases and the sintered body is likely to break. Therefore, the electric field applied during the polarization process is 1.0 to 2.0 Ec. A preferable applied electric field is 1.1 to 1.8 Ec, and a more preferable applied electric field is 1.2 to 1.6 Ec.

When the polarization treatment time is less than 0.5 minutes, the polarization is insufficient and sufficient characteristics cannot be obtained. On the other hand, when the polarization treatment time exceeds 30 minutes, the time required for the polarization treatment becomes long and the production efficiency is inferior. Therefore, the polarization treatment time is 0.5 to 30 minutes. A preferable polarization treatment time is 0.7 to 20 minutes, and a more preferable polarization treatment time is 0.9 to 15 minutes.
The polarization treatment is performed in an insulating oil heated to the above-described temperature, for example, a silicon oil bath. The polarization direction is determined according to a desired vibration mode. That is, in the thickness shear mode, polarization is performed in a direction parallel to the main surface, and in the thickness longitudinal mode, polarization is performed in a direction perpendicular to the main surface.
The piezoelectric ceramic is polished to a desired thickness, and then a vibrating electrode is formed. Next, after being cut into a desired shape by a dicing saw or the like, it functions as a piezoelectric resonator.

  Patent Documents 2 and 3 disclose a firing method in which oxide particles are interposed between molded bodies in firing of a piezoelectric ceramic. However, neither Patent Document 2 nor Patent Document 3 discloses or suggests the point of adjusting the characteristics of the piezoelectric ceramic.

JP 2000-7444 A JP 2003-327477 A

In the above example, the paste-like property adjusting agent has been described, but other forms of the property adjusting agent can be used. For example, a plate-like property adjusting agent can be used. The plate-like property adjusting agent may be a molded body or a sintered body containing at least one component included in the raw material powder.
Moreover, although the example which prepares a characteristic regulator for each element of Pb, Mn, Nb, Ti, and Zr was shown above, the present invention is not limited to this. For example, a roasted powder obtained by pulverizing and mixing the above starting materials for the piezoelectric ceramic and roasting the mixture at, for example, about 1000 ° C. can be used as the property adjusting agent. In this case, the compounding amount of the element to be adjusted can be increased as compared with the piezoelectric ceramic.
Furthermore, although the piezoelectric ceramic has been described as a sintered member in the above, the present invention can be applied to sintered members such as magnetic bodies and dielectric bodies. Furthermore, the characteristics to be adjusted are arbitrary and can be widely applied to the adjustment of characteristics required for the sintered member.

As starting materials, lead oxide (PbO) powder, titanium oxide (TiO ₂ ) powder, zirconium oxide (ZrO ₂ ) powder, manganese carbonate (MnCO ₃ ) powder, and niobium oxide (Nb ₂ O ₅ ) powder were prepared. This raw material powder was weighed so that the molar ratio would be Pb _0.99 [(Mn _1/3 Nb _2/3 ) _0.10 Ti _0.53 Zr _0.37 ] O _3, and then each ball mill was used. Wet mixing was performed for 10 hours to prepare a slurry.

  The obtained slurry was sufficiently dried and press-molded, and then calcined in the air at 800 ° C. for 2 hours. After finely pulverizing with a ball mill until the calcined body had an average particle size of 0.7 μm, the finely pulverized powder was dried. An appropriate amount of PVA (polyvinyl alcohol) as a binder was added to the dried finely pulverized powder and granulated. About 3 g of the granulated powder was put into a mold having a cavity with a length of 20 mm and a width of 20 mm and molded at a pressure of 245 MPa using a uniaxial press molding machine to obtain a molded body.

Zirconium oxide (ZrO ₂ ) powder having an average particle size of 40 μm, which was roasted at 1600 ° C., was applied to the obtained molded body. Further, zirconium oxide (ZrO ₂₎ powder 30 wt%, or 50 wt% including paste (binder: PVA) was applied to the molded body obtained a. Then, after performing a binder removal process with respect to a molded object, the main baking which hold | maintains at 1150-1250 degreeC in air | atmosphere for 2 hours was performed, and the sintered compact was obtained. Incidentally, zirconium oxide (ZrO ₂₎ without to apply a powder, and to obtain a sintered body in the same manner also without applying a paste containing a zirconium oxide (ZrO ₂₎ powder compact.

  After flattening both sides of each obtained sintered body with a lapping machine to a thickness of 0.5 mm, cutting to 15 mm × 7 mm, and provisional electrodes for polarization are formed at both ends (7.0 mm direction) Formed. Thereafter, a polarization treatment was performed by applying an electric field of 3 kV / mm for 20 minutes in a silicon oil bath at a temperature of 150 ° C. The polarization direction was a direction parallel to the plate, and the vibration mode was a thickness-shear mode. Thereafter, the temporary electrode was removed. The sample size after removal of the temporary electrode is 15 mm × 7 mm × 0.5 mm. Polishing was again performed to a thickness of about 0.3 mm with a lapping machine, and a test piece of length × width × thickness = 3.5 mm × 0.6 mm × 0.3 mm was cut out by cutting.

This test piece was placed in a constant temperature bath of 20 ° C., and the oscillation frequency F ₀ (20 ° C.) when the temperature was sufficiently stabilized was measured with a frequency counter (53181A manufactured by Agilent Technologies). A sample for which the oscillation frequency F _{0 at} 20 ° C. (20 ° C.) was measured was placed in a 125 ° C. thermostat, and the oscillation frequency F ₀ (125 ° C.) when the temperature was sufficiently stabilized was measured. From the measurement results, the change rate δF ₀ (125 ° C.) of the oscillation frequency was calculated from the following equation (1). The above measurement results are shown in FIG. Note that δF ₀ (125 ° C.) is not necessarily preferably 0%, and may be desired to be controlled to a predetermined value.

As shown in FIG. 3, the temperature characteristic δF ₀ (125 ° C.) of the oscillation frequency varies depending on the amount of ZrO ₂ that is a characteristic adjusting agent. Therefore, it was found that the characteristics of the piezoelectric ceramic can be adjusted by appropriately adjusting the characteristic adjusting agent. In FIG. 3, the “adhesion amount” indicates the weight of the applied paste when the paste is applied, and the weight of the applied ZrO ₂ powder when the ZrO ₂ powder is applied. The same applies to the following.

A composition analysis was performed on the obtained sintered body to obtain a Zr / Ti ratio (molar ratio). The result is shown in FIG. 4, and the Zr / Ti ratio in the sintered body increases as the amount of ZrO ₂ as a property adjusting agent increases. It was confirmed that the characteristics of the piezoelectric ceramic fluctuated with the variation of the composition.

In the case of the above example, the composition of the piezoelectric ceramic to be finally obtained, particularly the Zr / Ti ratio (molar ratio) is 0.736, and the temperature characteristic δF ₀ (125 ° C.) of the oscillation frequency to be obtained is 0.17%. Assume that In this case, by performing binder removal and sintering in a state where 0.01 g of the paste containing 50 wt% of zirconium oxide (ZrO ₂ ) powder roasted at 1600 ° C. is applied to the molded body, A piezoelectric ceramic having desired characteristics can be obtained.

Next, ZrO ₂ powder (average particle size: 40 μm) having a roasting temperature of 800 ° C. and 1000 ° C. is prepared, and the same property adjusting agent paste as described above is prepared and applied to the molded body (coating amount 0.0024 g). ) And firing was performed. The obtained sintered body in the same manner as described above Zr / Ti ratio (molar ratio) was determined .delta.F ₀ to (125 ° C.). The results are shown in FIGS. 5 and 6. As the roasting temperature is lower, the Zr / Ti ratio (molar ratio) is higher, and δF ₀ (125 ° C.) can be adjusted to a higher value. This is because the lower the roasting temperature, the lower the chemical stability of the ZrO ₂ powder, and thus the higher the reactivity, and the higher the roasting temperature, the higher the chemical stability of the ZrO ₂ powder, the more reactive. It is understood that it is caused by the low. This suggests that when adjusting the characteristics of the piezoelectric ceramic, ZrO ₂ powders having different roasting temperatures can be used in the case of ZrO ₂ powders in addition to the amount of the property adjusting agent for the molded body. is doing.

The PbO amount (mole) and δF ₀ (125 ° C.) of the sintered body were determined in the same manner as in Example 1 except that the following was used as a property adjusting agent. The results are shown in FIGS.
The property adjusting agent is the starting material of Example 1 (lead oxide (PbO) powder, titanium oxide (TiO ₂ ) powder, zirconium oxide (ZrO ₂ ) powder, manganese carbonate (MnCO ₃ ) powder, niobium oxide (Nb ₂ O _5). ) Powder) was weighed to a molar ratio of Pb _1.02 [(Mn _1/3 Nb _2/3 ) _0.10 Ti _0.53 Zr _0.37 ] O _3, and each was then used with a ball mill. A slurry was prepared by wet mixing for 10 hours. The slurry was sufficiently dried and press-molded, and then baked at 1000 ° C. in the atmosphere to obtain a powdery property modifier with an average particle size of 40 μm. A paste (binder: PVA) containing 50 wt% of this powder was produced.

As shown in FIGS. 7 and 8, by using a characteristic adjusting agent having the same composition as the composition of the starting material in the piezoelectric ceramic, the temperature characteristic δF ₀ (125 ° C.) ) Can be adjusted.

It is a perspective view which shows the structure of a piezoelectric body resonator. It is sectional drawing which shows the structure of a resonator. 4 is a graph showing the relationship between the amount of a property adjusting agent applied or applied and the temperature characteristic δF ₀ (125 ° C.) of the oscillation frequency in Example 1. 4 is a graph showing the relationship between the amount of a property adjusting agent applied or applied and the Zr / Ti ratio (molar ratio) in Example 1. ₂ is a graph showing the relationship between the roasting temperature of ZrO ₂ powder and the Zr / Ti ratio (molar ratio) in Example 1. 4 is a graph showing the relationship between the roasting temperature of ZrO ₂ powder and the temperature characteristic δF ₀ (125 ° C.) of the oscillation frequency in Example 1. It is a graph which shows the relationship between the quantity of the characteristic adjustment agent apply | coated or apply | coated in Example 2, and PbO (mol). 6 is a graph showing the relationship between the amount of a property adjusting agent applied or applied and the temperature characteristic δF ₀ (125 ° C.) of the oscillation frequency in Example 2.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Resonator, 2 ... Piezoelectric resonator, 22, 23 ... Vibration electrode, 3 ... Board | substrate, 31, 32 ... Terminal electrode, 4 ... Conductive stator, 5 ... Cap

Claims (5)

A step of performing composition analysis of the raw material powder in a molded body composed of the raw material powder;
Based on the result of the composition analysis, the step of firing the molded body in a state in which the molded body is brought into contact with a property adjusting agent containing at least one component included in the raw material powder;
The characteristic adjustment method of the sintered member characterized by having provided.   2. The sintered member according to claim 1, wherein the molded body is fired in a state in which the property adjusting agent containing a component less than a desired composition in the sintered member is in contact with the molded body. Characteristics adjustment method.   The method for adjusting the properties of a sintered member according to claim 1 or 2, wherein the property adjusting agent is a powder containing at least one of the components contained in the raw material powder.   The method for adjusting characteristics of a sintered member according to any one of claims 1 to 3, wherein the property adjusting agent is applied to the molded body as a paste as a mixture with a binder. The sintered member is a piezoelectric ceramic mainly composed of lead zirconate titanate having a perovskite structure,
The method for adjusting characteristics of a sintered member according to any one of claims 1 to 4, wherein the characteristic adjusting agent is ZrO ₂ powder.

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