JPWO2016006580A1 - Ceramic sintered body, method for producing ceramic sintered body, and piezoelectric ceramic electronic component - Google Patents

Abstract

The main component of the piezoelectric ceramic is formed of a perovskite type compound such as PZT. Nb and / or Sb is contained at 0.6 wt% or more, and Ce, Tb, Dy, Ho, and / or Er is contained at 0.05 wt% or more. It is also preferable to contain 0.29 wt% or more of Ni, Fe, Co, Mn, Mg, and / or Zn. The crystal axes of the crystal grains are {100} oriented, and have an orientation with a degree of orientation of 0.5 or more by the Lotgering method when a 3T magnetic field is applied. The ceramic body 1 is formed using this piezoelectric ceramic. This realizes a piezoelectric ceramic having a sufficient crystal orientation even when a weak magnetic field is applied, and a method for manufacturing the piezoelectric ceramic, and by using this piezoelectric ceramic, a piezoelectric ceramic electron capable of obtaining a better electromechanical coupling coefficient can be obtained. Realize the parts.

Description

  The present invention relates to a ceramic sintered body, a method for producing a ceramic sintered body, and a piezoelectric ceramic electronic component, and more specifically, a ceramic sintered body in which specific crystal planes of crystal grains are oriented in a predetermined direction, and a method for producing the same. The present invention relates to a piezoelectric ceramic electronic component such as a laminated piezoelectric actuator using a ceramic sintered body.

  Today, piezoelectric ceramic electronic components are mounted on various electronic devices. In these piezoelectric ceramic electronic components, ceramic sintered bodies mainly composed of various ceramic materials are widely used.

  This type of ceramic sintered body is known to improve various characteristics such as piezoelectric characteristics by controlling the orientation of specific crystal planes of crystal grains, and by applying a magnetic field to the crystal grains Orientation is possible.

  As a method of forming a magnetic field, a method using a permanent magnet and a method using an electromagnet are conventionally known.

  However, when a permanent magnet is used, even a neodymium magnet that can obtain the strongest magnetic field at the present time can only obtain a magnetic flux density of about several hundred mT on the maximum magnet surface. Moreover, since the magnetic field actually applied to the crystal grains is inversely proportional to the square to the third power of the distance from the magnet surface, the applied magnetic field is further reduced. Therefore, it is difficult for a permanent magnet to orient a specific crystal plane of crystal grains to such an extent that desired piezoelectric characteristics are obtained.

  On the other hand, for the electromagnet, a normal electromagnet in which a coil is formed by winding a conducting wire such as Cu around a hollow cylindrical bore made of a nonmagnetic material or a columnar magnetic core made of a magnetic material, and Cu etc. There is a superconducting electromagnet using a superconducting wire instead of the conducting wire, and the magnetic flux density can be increased by controlling the current and the number of turns to be energized, and a strong magnetic field can be realized.

  However, when a normal electromagnet is energized with an excessively large current, Joule heat is generated and the coil may be burned out. A water-cooled normal electromagnet that removes the Joule heat with a cooling device is also known. However, in a general normal electromagnet, only a weak magnetic field having a magnetic flux density of about 1 T is obtained at present.

  On the other hand, the superconducting electromagnet has no electrical resistance and does not generate Joule heat. Therefore, it is possible to energize a large current and realize a strong magnetic field having a magnetic flux density of 10 T or more. .

  For example, Patent Document 1 and Patent Document 2 are known as techniques for orienting crystal grains by applying such a strong magnetic field of 10 T or more.

  Patent Document 1 discloses an orientation having a step of obtaining a ceramic slurry containing polycrystalline ceramic powder, a step of forming the ceramic slurry in a magnetic field to obtain a ceramic formed body, and a step of firing the ceramic formed body. The method for producing ceramics, wherein the polycrystalline ceramic powder is contained in a proportion of 5 mol parts or less (excluding 0 mol parts) with respect to a main component having a perovskite structure and 100 mol parts of the main components. And the subcomponent is at least one selected from the group consisting of 3d transition metal ions whose magnetic moment is not zero or rare earth transition metal ions whose magnetic moment is not zero. Has been proposed.

In Patent Document 1, BaTiO ₃ or Pb (Zr _0.5 Ti _0.5 ) O ₃ is used as a main component, and Md ²⁺ , Fe ³⁺ , Fe ³⁺ , 3d transition metal ions or rare earth transition metal ions whose magnetic moment is not zero. Orientation degree by the Lotgering method of 10.4-85.4% by containing Ce ³⁺ , Nd ³⁺ , Sm ³⁺ and Dy ³⁺ in the main component and applying a 12T magnetic field. Obtaining ceramic.

  Patent Document 1 does not describe a means for generating a magnetic field, but it is considered that a superconducting electromagnet is used because a strong magnetic field with a magnetic flux density exceeding 10 T is realized.

  Patent Document 2 discloses a step of placing a first slurry in which a metal oxide powder containing at least a metal element constituting ceramics is dispersed on a substrate, and a magnetic field applied to the first slurry. Applying and solidifying to form an undercoat layer made of a first molded body; and placing a second slurry containing metal oxide powder constituting the ceramic on the undercoat layer; Applying a magnetic field to the second slurry to solidify it to form a second molded body to obtain a laminate of the second molded body and the undercoat layer; and the second molded body. And firing after removing the undercoat layer from the laminate of the undercoat layer, or removing the undercoat layer after firing the laminate of the second molded body and the undercoat layer, Cera which has the process of obtaining the ceramic which consists of a 2nd molded object Method of manufacturing a box has been proposed.

  In Patent Document 2, 0.05 to 10 wt% of a magnetic metal such as Fe, Co, Ni, Gd, Tb, Dy, Ho, Er, and Tm is contained in a metal oxide powder having a tungsten bronze structure or a perovskite structure. Or containing Mn oxide and orienting crystal grains in a strong magnetic field of 10T.

In Patent Document 2, a superconducting electromagnet is used as a magnetic field forming means, and a magnetic field of 10 T is applied to a slurry in which manganese oxide is contained in BaTiO ₃ having a perovskite structure, whereby orientation by the Lotgering method is performed. Ceramics with a degree of 29% are obtained.

JP 2008-37064 A (Claim 1, Table 1, Table 2, etc.) JP 2011-230373 A (Claim 1, paragraph numbers [0026], [0027], [0066] to [0081], etc.)

  However, in Patent Document 1 and Patent Document 2, although a superconducting electromagnet is used to generate a strong magnetic field of 10 T or more and crystal grains are oriented, a strong magnetic field is generated in a large space for the following reasons. It is difficult.

  That is, the superconducting material which is the main component of the superconducting electromagnet has a critical magnetic field, and when the specific magnetic field is exceeded, the superconducting state is broken and returns to the normal conducting state. For this reason, there is a limit to the magnitude of the magnetic field generated in the vicinity of the coil.

  Moreover, in the superconducting electromagnet, the magnetic flux density decreases in inverse proportion to the square of the distance from the coil to be energized, so when using the magnetic field generated inside the bore, when the bore diameter increases, The magnetic field weakens rapidly.

  As described above, a superconducting electromagnet has a limit in increasing the magnetic field because of the presence of a critical magnetic field, and the magnetic field generated inside rapidly decreases as the diameter of the bore increases. For this reason, commercially available superconducting electromagnets have a bore diameter of about 100 mm when the central magnetic field is about 10 T, and a bore diameter of about 50 mm when the central magnetic field is about 15 T. Therefore, it is difficult to use superconducting electromagnets for applications that require industrial mass productivity.

  In addition, when a substance mainly composed of crystal grains having no ferromagnetism is oriented by applying a magnetic field, the rotational moment acting on the crystal grains is proportional to the square of the applied magnetic field. For this reason, when the magnitude of the magnetic field is weakened, it becomes increasingly difficult to obtain oriented ceramics having a large degree of orientation. For example, when the magnetic field is reduced from 12T to 3T, the rotational moment is reduced to 1/16, and thus it becomes extremely difficult to obtain oriented ceramics having a desired large degree of orientation.

Furthermore, in Patent Document 2, even when a 10T magnetic field is applied, the degree of orientation is only 29%. Therefore, in order to obtain a larger electromechanical coupling factor k ₃₁ is realized in the sintered ceramic body is desired to have a greater degree of orientation.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a ceramic sintered body having sufficient crystal orientation even when a weak magnetic field is applied, and a method for producing the ceramic sintered body. An object of the present invention is to provide a piezoelectric ceramic electronic component capable of obtaining a better electromechanical coupling coefficient by using a ceramic sintered body.

  As a ceramic material used for the piezoelectric body, a composite oxide having a perovskite crystal structure such as lead titanate (hereinafter referred to as “PT”) or lead zirconate titanate (hereinafter referred to as “PZT”) ( Hereinafter, “perovskite type compounds”) are widely used.

  Therefore, the present inventors conducted extensive research using PZT, and as a result, contained at least one element of Nb and Sb in an amount of 0.6 wt% or more, and Ce, Tb, Dy from rare earth elements. A ceramic sintered body having good crystal orientation can be obtained even when a 3T weak magnetic field is applied by selecting at least one element selected from Ni, Ho, and Er and containing 0.05 wt% or more. I got the knowledge that I can.

  Since PZT has a small magnetocrystalline anisotropy and no ions having a large magnetic moment, it is difficult to impart orientation by applying a magnetic field. However, even if PZT is difficult to impart orientation, as described above, by refining the additive element and its content, remarkably superior orientation can be obtained by applying a weak magnetic field. It is considered that the present invention can also be applied to other perovskite type compounds such as PT which have a small magnetocrystalline anisotropy and do not have a large magnetic moment.

The present invention has been made on the basis of such knowledge, and the ceramic sintered body according to the present invention contains, as a main component, a composite oxide having a perovskite crystal structure represented by the general formula A _m BO _3. , Nb and Sb, the first subcomponent containing at least one element is contained in an amount of 0.6 wt% or more, and at least one selected from Ce, Tb, Dy, Ho, and Er The second subcomponent including the element is contained in an amount of 0.05 wt% or more, and a specific crystal plane of the crystal grain is oriented in a predetermined direction.

  The ceramic sintered body of the present invention includes at least the first and second subcomponents and includes at least one element selected from Ni, Fe, Co, Mn, Mg, and Zn. It is also preferable that the third subcomponent is contained in an amount of 0.29 wt% or more.

  The third subcomponent has a large magnetic moment and dissolves in the B site as an acceptor. Therefore, in combination with the first subcomponent dissolved in the B site as a donor, the third subcomponent has a large magnetic moment or a large magnetic moment. The amount of solid solution at the B site of the element having the magnetocrystalline anisotropy can be increased, which makes it possible to impart further orientation to a specific crystal plane of the crystal grain.

  In the ceramic sintered body of the present invention, the content of the third subcomponent with respect to the content of the first subcomponent is preferably 0.45 to 0.54 in molar ratio.

  Furthermore, in the ceramic sintered body of the present invention, it is preferable that the total content of the subcomponents other than the main component is 5 mol parts or more with respect to 100 mol parts of the main components.

  In this way, by adjusting the content ratio of the first subcomponent and the third subcomponent, even if the total amount of subcomponents is 5 mol parts or more with respect to 100 mol parts of the main component, the electrical characteristics are deteriorated. In addition, a ceramic sintered body having a greater degree of orientation can be easily obtained even with a weaker magnetic field than in the past.

  In the ceramic sintered body of the present invention, the specific crystal plane is preferably a {100} plane.

  Furthermore, in the ceramic sintered body of the present invention, the specific crystal plane is preferably a {100} plane, and the degree of orientation by the Lotgering method is preferably 0.5 or more.

  In the ceramic sintered body of the present invention, the specific crystal plane is a {100} plane, and the crystal grains are oriented by applying a magnetic field and within a range of 20 ° or less with respect to the direction of the magnetic field application. The abundance ratio of the crystal grains in which the {100} planes of the crystal grains are oriented in the predetermined direction is preferably 50% or more in terms of a cross-sectional area ratio.

  In the ceramic sintered body of the present invention, the abundance ratio is calculated based on an analysis result based on the electron beam backscatter diffraction method.

  In the ceramic sintered body of the present invention, the composite oxide is preferably a PZT compound.

  The ceramic sintered body of the present invention has an average particle diameter of 0.5 to 0.5 when the width of a field of view in which 100 or more of the crystal particles are contained in one field of view is observed with a scanning electron microscope. It is preferably 5 μm.

The method for producing a ceramic sintered body according to the present invention includes a composite oxide having a perovskite crystal structure represented by the general formula A _m BO ₃ as a main component, and a ceramic sintered body containing a plurality of subcomponents. And a raw material containing a plurality of raw materials containing the element as the main component, a first subcomponent containing at least one element of Nb and Sb, and Ce as a ceramic raw material, A raw material containing a second subcomponent containing at least one element selected from Tb, Dy, Ho, and Er, and weighing the ceramic raw material; A synthesis step of producing a composite of the raw material and the first and second subcomponents, and a ceramic slurry preparation step of slurrying the composite to prepare a ceramic slurry; The ceramic slurry is subjected to a forming process while applying a magnetic field to produce a ceramic molded body, and a firing step of firing the ceramic molded body, and the weighing step includes the first subcomponent And the ceramic raw material is weighed so that the respective contents of the second subcomponent are 0.05 wt% or more and 0.6 wt% or more after firing, respectively, The magnetic field applied to is not more than 9T.

  In the method for producing a ceramic sintered body according to the present invention, the magnetic field applied to the ceramic slurry is preferably 3 to 5T.

  That is, a superconducting electromagnet that generates a magnetic field of 3 to 5T can have a larger bore diameter than a superconducting electromagnet that generates a strong magnetic field of 9T or more. Therefore, by using the manufacturing method of the present invention, a desired orientation can be obtained by applying a relatively weak magnetic field of 3 to 5 T. Therefore, a molded body oriented using a superconducting electromagnet having a large bore diameter. Can be produced. As a result, productivity is greatly improved, and a desired ceramic sintered body can be easily manufactured at low cost.

  In the method for producing a ceramic sintered body according to the present invention, the weighing step may include a third subcomponent containing at least one element selected from Ni, Fe, Co, Mn, Mg, and Zn. It is preferable to weigh the contained raw material so that the content of the third subcomponent after firing is 0.29 wt% or more.

  Also, in the method for producing a ceramic sintered body according to the present invention, in the forming body producing step, a hollow electromagnet having an axial direction as a conveying direction of the ceramic slurry is arranged, and a magnetic field is provided in an in-plane direction of the ceramic slurry. It is preferable to apply an orientation treatment while passing the ceramic slurry through the hollow portion of the electromagnet.

  That is, since the coil is wound around the outer periphery of the hollow electromagnet shaft, the magnetic field lines extend over a wide range in the axial direction of the electromagnet. Therefore, since the magnetic field application area becomes wide in the axial direction, a magnetic field is applied to the ceramic slurry moving in the conveying direction for a long time, enabling mass production of the oriented ceramic slurry, and mass production. A suitable manufacturing method can be realized.

  The piezoelectric ceramic electronic component according to the present invention is a piezoelectric ceramic electronic component in which an external electrode is formed on the surface of a ceramic body having a piezoelectric ceramic layer, wherein the piezoelectric ceramic layer is the ceramic sintered body according to any one of the above. It is characterized by being formed.

  According to the ceramic sintered body of the present invention, the above-mentioned predetermined amount of the first subcomponent is contained, the predetermined amount of the second subcomponent having a large magnetic moment is contained, and the crystal grains are specified. Since the crystal plane is oriented in a predetermined direction, it is possible to obtain a ceramic sintered body having excellent orientation that is remarkably superior to conventional ones only by devising the component composition.

  Further, according to the method for producing a ceramic sintered body of the present invention, the contents of the first subcomponent and the second subcomponent in the weighing step are 0.05 wt% or more and 0.6 wt% or more, respectively, after firing. In the molded body production process performed by weighing the ceramic raw material and performing the synthesis process and the ceramic slurry production process, the magnetic field applied to the ceramic slurry is 9 T or less (preferably 3 to 5 T). As a result, it is possible to provide sufficient orientation with a weak magnetic field without applying a strong magnetic field of 10 T or more as in the prior art, and it is possible to obtain a ceramic sintered body having good orientation at low cost. It becomes.

  In addition, according to the piezoelectric ceramic electronic component of the present invention, in the piezoelectric ceramic electronic component in which an external electrode is formed on the surface of a ceramic body having a piezoelectric ceramic layer, the piezoelectric ceramic layer is any one of the ceramic firing described above. Piezoelectric ceramic electronic components with good piezoelectric characteristics with high electromechanical coupling coefficient at low cost because it is possible to obtain good orientation by simply devising the composition of the ceramic sintered body. Can be obtained.

1 is a cross-sectional view showing an embodiment of a multilayer piezoelectric actuator as a piezoelectric ceramic electronic component according to the present invention. It is the figure which showed an example of the measurement result of a X-ray diffraction spectrum, (a) is the same composition as the sample number 9, Comprising: The figure which showed the X-ray diffraction spectrum of the non-orientated sample, (b) is the sample number 9 It is the figure which showed X-ray diffraction spectrum of. It is a figure which shows the relationship between the various rare earth elements which used the magnetic field in Example 1 as a parameter, and orientation. It is a figure which shows the relationship between the magnetic field about each sample of Example 3, and orientation degree. It is a mapping image which shows the EBSD analysis result of the sample number 31. It is a mapping image which shows the EBSD analysis result of the non-oriented sample which has the same component composition as the sample number 31, and did not apply a magnetic field.

  Next, an embodiment of the present invention will be described in detail.

The ceramic sintered body according to the present invention contains a perovskite type compound represented by the general formula A _m BO ₃ as a main component. The ceramic sintered body contains 0.6 wt% or more of the first subcomponent containing at least one element of Nb and Sb, and is made of Ce, Tb, Dy, Ho, and Er. The second subcomponent containing at least one element selected from the inside is contained in an amount of 0.05 wt% or more, and specific crystal planes of the crystal grains are oriented in a predetermined direction.

  Here, the specific crystal plane refers to a plane whose normal is the direction of easy magnetization of crystal grains, and in the present embodiment, it means any one of (100), (010), and (001). As described later, {100} plane is used.

  The predetermined direction refers to the magnetic field application direction. Here, in the case of a ceramic sintered body in which the magnetic field application direction is unknown, the ceramic sintered body is cut in an appropriate cross section, and pole figure measurement by X-ray diffraction method (XRD) or crystal particle orientation by electron beam backscatter diffraction method By analyzing the distribution in the crystal orientation direction by analysis and fitting the distribution with a Gaussian distribution or the like, the center direction of the distribution can be set as a predetermined direction.

  As described above, in the present embodiment, by devising the component composition contained in the ceramic sintered body and orienting specific crystal planes of crystal grains in a predetermined direction, a perovskite compound having a small crystal magnetic anisotropy is used. Even in such a case, a ceramic sintered body having high orientation can be obtained by applying a weak magnetic field of about 3T, and a piezoelectric ceramic electronic component having good piezoelectric characteristics having a large electromechanical coupling coefficient can be obtained at low cost. it can.

  The main component is not particularly limited as long as it is a perovskite type compound, but in the present embodiment, a PZT system or a PT system having good piezoelectric characteristics is preferred although the magnetocrystalline anisotropy is small. Can be used.

In the perovskite type compound represented by the general formula A _m BO ₃ , the molar ratio m (= A / B) between the element dissolved in the A site and the element dissolved in the B site is the stoichiometric composition. Is 1.000, but can be changed within a range that does not affect the characteristics.

  Hereinafter, the reason why the element types and contents of the first and second subcomponents are limited as described above will be described in detail.

(1) First subcomponent Since PZT and PT have small magnetocrystalline anisotropy, it is difficult to orient crystal grains by themselves even when a magnetic field is applied.

  However, by including Nb and / or Sb as the first subcomponent in the ceramic sintered body together with the second subcomponent, high orientation is imparted even when a weak magnetic field of about 3 T is applied. can do.

  That is, Nb and Sb have the effect of increasing the magnetocrystalline anisotropy of the perovskite type compound.

  On the other hand, Nb and Sb have an ion radius close to that of Ti or Zr. For this reason, when an Nb compound or an Sb compound is added to the main component, these elements act as donors in the synthesis process, and a part of Ti and Zr is substituted to form a solid solution at the B site. Nb and Sb form an oxygen octahedral structure and strongly bond with oxygen ions surrounding Ti ions and Zr ions.

  Thus, by dissolving Nb and / or Sb in the B site, combined with the addition effect of the second subcomponent, it contributes to the improvement of orientation even in a weak magnetic field of about 3T.

  For this purpose, the total content of Nb and / or Sb as the first subcomponent is required to be at least 0.06 wt% or more.

  When the first subcomponent is less than 0.06 wt%, the content of the first subcomponent is too small, and even if the second subcomponent is contained, it is sufficient for a specific crystal plane of the crystal grain. It is not possible to impart a proper orientation.

  The upper limit of the content of the first subcomponent is not particularly limited, but considering piezoelectricity, sinterability and the like, Nb is 25 wt% or less, and Sb is 4.5 wt% or less. preferable.

(2) Second subcomponent Since the ionic radius of the rare earth element is close to the ionic radius of Pb, when the rare earth compound containing the rare earth element is added to the main component, the rare earth element is a part of Pb during the synthesis process. Substitution takes place and forms a solid solution at the A site, and part of the rare earth element enters a gap in the oxygen octahedron structure surrounding the element present at the B site.

  Many rare earth elements have a large magnetic moment, but since they are not strongly covalently bonded to the main component, the driving force for imparting orientation to specific crystal planes of crystal grains is considered to be weak.

  However, when the rare earth element is dissolved in the A site, the rare earth element strengthens the interaction of the magnetic moments between nearby unit lattices, so the magnetic moments of the ions existing at the B site are uniform even in a weak magnetic field of about 3T. As a result, sufficient orientation can be imparted to the crystal grains even in a weak magnetic field of about 3T.

  That is, only the first subcomponent does not cause sufficient interaction between neighboring unit lattices, making it difficult to align the magnetic moment. For this reason, it is necessary to forcibly arrange the magnetic moments.

  However, by adding a rare earth element having a large magnetic moment as the second subcomponent and dissolving it at the A site, the interaction of magnetic moments between neighboring unit lattices can be strengthened. Even when it is applied, the magnetic moments at the B site are easily aligned, and this makes it possible to impart sufficient orientation even when a weak magnetic field is applied.

  And as such a rare earth element, it is preferable to use Ce, Tb, Dy, Ho, and Er. Other rare earth elements, for example, rare earth elements such as La, Pr, Nd, Eu, Gd, Tm, Yb, and Lu, have a smaller magnetic moment of ions than the magnetic moment of ions of Tb, Dy, Ho, and Er. . Therefore, since these rare earth elements having a small magnetic moment are considered to lack the effect of enhancing the interaction of magnetic moments between adjacent unit lattices, a strong magnetic field of about 5 to 9 T is required to obtain a desired orientation. It is necessary to apply.

  The Ce ions described above have an effect of effectively strengthening the interaction of magnetic moments between adjacent unit lattices, although the magnetic moment is smaller than those of Pr, Nd, Eu, Gd, or Tm. Since it contributes to the provision of orientation, it is suitable for use as the second subcomponent.

  Thus, Ce, Tb, Dy, Ho, and Er have a large magnetic moment and / or can effectively enhance the interaction of magnetic moments between adjacent unit lattices. It is possible to impart sufficient orientation.

  Therefore, in the present embodiment, Ce, Tb, Dy, Ho, and Er are used as the second subcomponent among rare earth elements.

  Further, the content of the second subcomponent is required to be at least 0.05 wt%. When the content of the second subcomponent is less than 0.05 wt%, even if the first subcomponent is contained, it is difficult to align the magnetic moment in a weak magnetic field of about 3 T, and the crystal grains are not aligned with a specific crystal plane. Sufficient orientation cannot be imparted.

  The upper limit of the content of the second subcomponent is not particularly limited, but is preferably about 3.5 to 4.5 wt% from the viewpoint of piezoelectricity, sinterability, heat resistance, and the like. .

  As described above, in the present embodiment, by including the predetermined amount of the first second subcomponent described above, sufficiently high orientation is imparted even when a weak magnetic field of about 3 T is applied to the crystal particles. A ceramic sintered body can be obtained.

  And the orientation of a crystal grain can be evaluated by the Lotgering method using an X-ray diffraction spectrum, for example.

  That is, according to the Lotgering method, the degree of orientation F can be expressed by Equation (1).

Here, ΣI (HKL) is the sum of X-ray peak intensities of a specific crystal plane (HKL) of the oriented sample, and ΣI (hkl) is the X-ray peak intensities of all crystal planes (hkl) of the oriented sample. It is the sum. ΣI ₀ (HKL) is the sum of X-ray peak intensities of a specific crystal plane (HKL) of a reference sample, for example, a non-oriented sample, and ΣI ₀ (hkl) is the total crystal plane (hkl) of the reference sample. Is the sum of the X-ray peak intensities.

  Therefore, the X-ray peak intensity in each crystal plane can be calculated from the X-ray diffraction spectrum, and the degree of orientation F can be obtained based on the formula (1).

  In order to obtain a sufficient electromechanical coupling coefficient, specific crystal planes of crystal grains, for example, {100} planes are oriented in a predetermined direction, and the degree of orientation F is 0.5 or more by the Lotgering method. It is preferable. In the present embodiment, a ceramic sintered body having the orientation degree F of 0.5 or more is obtained by applying a magnetic field of about 3T.

  Here, the notation {100} plane does not indicate only the (100) plane, but includes the (010) plane and the (001) plane in addition to the (100) plane. In a ceramic sintered body, a magnetic field is applied at the stage of the ceramic molded body, and even if the (100) plane, (010) plane, or (001) plane of crystal grains are oriented in a predetermined direction, the temperature rises during the firing process. However, since the crystal system changes from the tetragonal system to the cubic system, the (100) plane, (010) plane, and (001) plane are not distinguished. When the temperature is lowered to room temperature in this state, the crystal plane facing in a predetermined direction is randomly determined as one of the (100) plane, (010) plane, and (001) plane. The specific crystal plane used for the {100} plane.

  When measuring the X-ray diffraction spectrum using an XRD apparatus, if the area on the X-ray irradiation surface is small, the ceramic sintered body is further cut in a plane parallel to the cut surface, and the cut surface is the surface. The ceramic sintered bodies may be arranged so that the observation area is substantially expanded. Moreover, you may observe using the micro X-ray apparatus which can narrow down and observe the area irradiated with X-rays to a small spot. However, if the spot is extremely small and the number of ceramic particles contained in the X-ray irradiation range is extremely small, the possibility that the ceramic particles are accidentally oriented in the orientation direction cannot be denied. The diameter is preferably 10 times or more the average particle size of the ceramic particles.

It can be confirmed as follows that the crystal structure of the ceramic sintered body is a perovskite type structure. That is, the ceramic sintered body is ground into a powder, the powder is analyzed by XRD, and the obtained XRD chart is compared with a Powder Diffraction File (PDF). Specifically, for example, in the case of PT and PZT, powder X-ray diffraction data (PDF card # 70-0746) of PT described in MActa Crystallographica, Section b, Volume 34, pp.1065-1070 (1993) Compared with powder X-ray diffraction data of Pb (Zr _0.601 Ti _0.399 ) O ₃ (PDF card # 89-1280) described in, Journal of Physics: Condensed Matter, Volume 10, No. 28, pp.6241-6269 To do. And if the intensity ratio of each peak and the peak position with respect to the surface interval d are similar, it can be determined that the compound is a perovskite compound containing PT or PZT. In this case, it is desirable to use a PDF card having a composition similar to the ceramic sintered body to be analyzed. However, if there is no PDF card having a similar composition, the crystal structure may be specified by crystal structure analysis from XRD data. .

  The crystal orientation of the crystal particles can also be analyzed by using an EBSD (Electron back scattering diffraction) method.

  In this EBSD method, first, a ceramic sintered body is cut by a suitable cross section and polished, and an electron beam narrowly focused on the cut surface is irradiated from an oblique direction, thereby diffracting the electron beam scattered backward. Get the pattern Kikuchi pattern. Then, by analyzing this Kikuchi pattern, it is possible to specify the crystal orientation of the part where the electron beam is irradiated onto the cut surface. Therefore, by observing with a scanning electron microscope (SEM) and analyzing a wide range including 100 to 1000 or more crystal particles using the EBSD method, the distribution state of {100} planes of each crystal particle The orientation in which the distribution is concentrated can be set as the orientation orientation.

  In the ceramic sintered body, the abundance ratio of the crystal grains in which the {100} planes of the crystal grains are oriented in a predetermined direction within a range of 20 ° or less with respect to the magnetic field application direction is a cross-sectional area ratio of 50. It can be seen that the {100} plane of each crystal grain is concentrated and distributed in the magnetic field application direction. Hereinafter, in such a case, it is defined that the crystal grains are {100} oriented.

  Next, the manufacturing method of this ceramic sintered compact is demonstrated.

  First, as the ceramic raw material, a plurality of raw materials containing the elements constituting the main component, for example, in the case where the main component is PZT, a Pb compound, a Ti compound, a Zr compound, and the like are prepared. Furthermore, as the ceramic raw material, a compound containing a first subcomponent containing Nb and / or Sb and a compound containing a second subcomponent containing Ce, Tb, Dy, Ho and / or Er are prepared.

  In addition, the form of each ceramic raw material may be a simple substance, or any compound such as an oxide, carbonate, or hydroxide. Moreover, these mixtures may be sufficient and it does not specifically limit.

  Next, the ceramic raw material is weighed so that the content of the first subcomponent is 0.05 wt% or more and the content of the second subcomponent is 0.6 wt% or more after firing. To do.

  Next, these weighed ceramic raw materials are put into a ball mill containing a grinding medium such as PSZ (partially stabilized zirconia) balls and sufficiently wet-stirred in a solvent such as pure water to obtain a mixture.

  And after drying this mixture, it calcines and synthesize | combines and dry pulverizes and obtains ceramic raw material powder (synthetic product).

  Next, the ceramic raw material powder thus obtained is wet-mixed in a ball mill using an organic binder and a dispersant and pure water or the like as a solvent to produce a ceramic slurry.

  Thereafter, a normal electromagnet or a superconducting electromagnet having a bore is used, and a forming process is performed while applying a magnetic field of 9 T or less, preferably 3 to 5 T in a magnetic field, thereby obtaining a ceramic molded body.

  For example, a hollow electromagnet having a bore formed with the conveying direction of the ceramic slurry as an axial direction is arranged to apply a magnetic field in the in-plane direction of the ceramic slurry, and the ceramic slurry is formed into a bore (hollow part). The alignment treatment can be performed while passing through.

  That is, since the coil is wound around the outer periphery of the shaft core of the hollow electromagnet, the magnetic field lines can be wide in the axial direction of the electromagnet, and the magnetic field application region can be widened. A magnetic field can be applied to the ceramic slurry for a relatively long time.

  The thickness of the ceramic molded body is preferably about 12 to 100 μm. Furthermore, the average particle diameter of the crystal particles constituting the ceramic molded body is 0.5 to 0.5 when a wide field of view in which 100 or more crystal particles are included in one field of view is observed with a scanning electron microscope (SEM). About 5.0 μm is preferable.

  The average particle diameter can be defined as follows. That is, using a SEM, the polished surface of the cross section of the ceramic molded body is observed at a magnification that includes 100 or more crystal particles within one field of view and each particle is visible. For each crystal grain to be observed, the maximum value of the width in the direction in which the width is maximum is the major axis diameter, the maximum value in the direction orthogonal to the direction in which the width is maximum is the diagonal length, and the major axis The average of the diameter and the diagonal length is defined as the particle diameter. The particle diameter of each particle thus obtained is calculated for the particles observed in the field of view, and the average of these can be defined as the average particle diameter.

  In addition, when the grain boundary line cannot be clearly observed when the polished surface of the cross section of the ceramic molded body is observed with an SEM, the grain boundary of the polished surface may be chemically etched using an acid or the like. The boundary may be clarified by heat treatment.

  And this ceramic molded object is baked and a ceramic sintered compact is manufactured by this.

  As described above, according to the method for producing a ceramic sintered body, the contents of the first subcomponent and the second subcomponent in the weighing step are 0.05 wt% or more and 0.6 wt% or more, respectively, after firing. Thus, in the molded body production process performed by weighing the ceramic raw materials and performing the synthesis process and the ceramic slurry production process, the magnetic field applied to the ceramic slurry is 9 T or less (preferably 3 to 5 T). Therefore, even if a strong magnetic field of 10 T or more is not applied as in the prior art, sufficient orientation can be imparted with a weak magnetic field, and a ceramic sintered body having good orientation can be obtained at low cost. Become.

  Specifically, by applying a weak magnetic field of 9T or less, preferably 3 to 5T, to the crystal particles, the crystal particles are {100} oriented, and the degree of orientation F by the Lotgering method is 0.5 or more. In comparison, a ceramic sintered body to which a significantly higher orientation is imparted can be obtained.

  In addition, a superconducting electromagnet that generates a magnetic field of 3 to 5T can have a larger bore diameter than a superconducting electromagnet that generates a strong magnetic field of 9T or more. Therefore, when a magnetic field of 3 to 5 T is applied, crystal grains can be oriented using a superconducting electromagnet with a large bore diameter, which greatly improves productivity and reduces the cost of desired ceramic sintering. The body can be manufactured easily.

  In the above-described embodiment, the main component contains the first and second subcomponents, but at least one element selected from Ni, Co, Fe, Mn, Mg, and Zn is used as the third component. Inclusion as a subcomponent is preferable for further improving the orientation, and inclusion of such a third subcomponent makes it possible to obtain a larger electromechanical coupling coefficient.

  That is, Ni, Co, Fe, Mn, Mg, and Zn as the third subcomponent are similar to the first subcomponent Nb and Sb in terms of the elements existing at the B site such as Ti and Zr and the ion radius. Nearly, it dissolves in the B site as an acceptor. These third subcomponents have a large magnetic moment or an effect of increasing the magnetocrystalline anisotropy, which contributes to improving the orientation. In particular, when the content of the first subcomponent that dissolves in the B site as a donor is limited from the viewpoint of piezoelectricity and sinterability, the first subcomponent that acts as an acceptor is added to the first subcomponent. It is possible to facilitate the solid solution of the subcomponent of B to the B site, thereby further improving the orientation.

  In particular, when the content of the third subcomponent with respect to the content of the first subcomponent is 0.45 to 0.54 in terms of molar ratio, the total amount of the subcomponent is 5 mol parts with respect to 100 mol parts of the main component. Even if it carries out above, since electrical property deterioration does not occur and the responsiveness with respect to a magnetic field increases, the ceramic sintered compact to which the desired big orientation was provided with the magnetic field of 3-5T can be obtained easily.

  Here, 100 mole parts of the main component is defined as follows.

First, it is assumed that Pb, Ti, and Zr measured by the composition analysis form Pb _a (Ti, Zr) _b O _c . Next, the content of each element thus measured is divided by the atomic weight of each element and converted to a molar amount. Next, the molar amount of Pb is compared with the sum of the molar amounts of Ti and Zr, the larger one is regarded as the molar amount of the main component, and the molar amount of each element is set so that the molar amount of the main component is 100 mol parts. The amount is normalized and this is defined as 100 mole parts of the main component.

  Moreover, the total mole part of the subcomponent with respect to 100 mole parts of the main component is defined as follows. First, the molar amounts of elements other than Pb, Ti, and Zr are summed, and the molar amount is normalized by the same method as described above. Next, the molar amount of elements other than the standardized Pb, Ti, and Zr is divided by 100 mole parts of the main component, and this is multiplied by 100, and this is the total mole portion of subcomponents relative to 100 mole parts of the main component. Define.

  The composition of the ceramic sintered body is, for example, an XRF method (X-ray fluorescence analysis) and an ICP-AES method (Inductively Coupled Plasma-Atomic Emission Spectroscopy). Can be obtained by using together.

  In the XRF method, fluorescent X-rays that are excited and generated by irradiation with primary X-rays are detected, and qualitative and quantitative analysis of elements is performed. That is, by using the XRF method, it is possible to specify the element type from the detected fluorescent X-ray wavelength or the amount of the element from the intensity of the fluorescent X-ray wavelength.

  However, in the XRF method, since the X-ray intensity of the detected fluorescent X-ray slightly changes depending on the particle size, surface state, etc. of the ceramic sintered body, the content of the constituent elements of the ceramic sintered body is highly accurate. It is difficult to measure. Further, since the XRF method is a surface analysis, it is not suitable for the case where it is assumed that a gradient distribution or segregation of the composition exists between the surface and the inside, such as a ceramic sintered body. For this reason, first, the XRF method is used to identify the element type contained in the ceramic sintered body and measure the approximate content. Next, the ceramic powder obtained by pulverizing the ceramic sintered body is dissolved in nitric acid to form a solution, and the content of the element is determined using the ICP-AES method.

  If it is considered difficult to specify the constituent elements of the ceramic sintered body by the XRF method, quantitative analysis is performed using the ICP-AES method for the element types that can be analyzed without using the XRF method. Also good.

  By the way, in the ICP-AES method, as described above, the ceramic powder is made into a solution and the composition in the solution sample is analyzed. Therefore, an element that does not cause quantitative fluctuation in the solution process can be quantitatively analyzed. The amount of gaseous oxygen cannot be quantified. Therefore, although it is necessary to confirm that the oxygen component is contained in the ceramic sintered body, this can be confirmed by the following method.

  That is, a method for examining the amount of light elements by an EDX (Energy dispersive X-ray spectroscopy) method or a WDX (Wavelength dispersive X-ray spectroscopy) method, an XRD method (X- There is a method of checking the crystal structure by using a ray diffraction (X-ray diffraction) method and confirming that it has an oxide crystal structure. In addition, the ceramic sintered body is heated in an oxygen atmosphere to check whether or not gas is generated, and by checking the generated gas species, it is confirmed whether or not the sintered body before heating is an oxide. can do. And if it can confirm that a ceramic sintered compact is an oxide by these methods, it can be considered that components other than the element kind quantified by XRF method and ICP-AES method are oxygen.

  Further, when the piezoelectric ceramic electronic component is a laminated type having an internal electrode as described later, the internal electrode component may be eluted in the process of making the sample into solution when using the ICP-AES method. Therefore, if the piezoelectric ceramic body, which is a ceramic sintered body, is dissolved as it is to form a solution, the content of the metal element in the piezoelectric ceramic cannot be determined. For this reason, it is preferable to measure by the ICP-AES method after peeling or polishing and removing the internal electrode. In addition, each content of the first component, the second component, and the third component described above is set such that the weight of the ceramic sintered body immediately before being converted into a solution for analysis is 100 wt%, and the content of each element with respect to the weight The value is obtained as the atomic weight ratio. The polished surface may be quantitatively analyzed by the EDX method or the WDX method, and the element content may be obtained by comparing with a quantitative analysis value of a ceramic whose composition is known. Also in this case, the contents of the first component, the second component, and the third component are such that the weight of the ceramic sintered body at the analysis stage is 100 wt%, and the weight ratio of the atoms of each element to that The value obtained as

  Next, a piezoelectric ceramic electronic component manufactured using the ceramic sintered body will be described.

  FIG. 1 is a cross-sectional view showing an embodiment of a multilayer piezoelectric actuator as a piezoelectric ceramic electronic component according to the present invention. The multilayer piezoelectric actuator includes a piezoelectric ceramic body 1 and piezoelectric ceramic body 1. External electrodes 2a and 2b made of a conductive material such as Ag or Ni are provided at both ends. The piezoelectric ceramic body 1 is formed by alternately laminating piezoelectric ceramic layers made of the ceramic sintered body of the present invention and internal electrodes 3a to 3g made of a conductive material mainly composed of Ag, Pd, Pt, and the like. It is tied.

  In the laminated piezoelectric actuator, one end of the internal electrodes 3a, 3c, 3e, and 3g is electrically connected to one external electrode 2a, and one end of the internal electrodes 3b, 3d, and 3f is electrically connected to the other external electrode 2b. Has been. In the laminated piezoelectric actuator, when a voltage is applied between the external electrode 2a and the external electrode 2b, the laminated piezoelectric actuator is displaced in the laminating direction indicated by the arrow X due to the piezoelectric longitudinal effect, and is laminated as indicated by the arrow Y due to the piezoelectric lateral effect. Displacement in the direction perpendicular to the direction.

  A method for manufacturing the laminated piezoelectric actuator will be described in detail.

  First, a ceramic raw material powder is produced by the same method and procedure as described above.

  Next, the ceramic raw material powder obtained in this way is crushed, and then an organic binder and a dispersant are added and wet-mixed in a ball mill using pure water as a solvent to obtain a ceramic slurry. And after that, it forms using a doctor blade method etc., applying the magnetic field of 3-9T, and produces a ceramic green sheet by this.

  Next, using a conductive paste for internal electrodes mainly composed of Ag, Pd, Pt or the like, a conductive layer having a predetermined shape is formed on the ceramic green sheet by screen printing.

  Next, after laminating the ceramic green sheets on which these conductive layers are formed, the ceramic green sheets are sandwiched between the ceramic green sheets on which the conductive layers are not formed, and pressure-bonded. Thus, a ceramic laminate in which conductive layers and ceramic green sheets are alternately laminated is produced. Next, the ceramic laminate is cut into a predetermined size and accommodated in an alumina pod (sheath), and after a binder removal treatment at a predetermined temperature (for example, 250 to 500 ° C.), under a predetermined atmosphere (for example, Firing in a reducing atmosphere) and a predetermined temperature (for example, 1000 to 1200 ° C.) to form the piezoelectric ceramic body 1 in which the internal electrodes are embedded.

  Next, a conductive paste for an external electrode made of Ni—Cu alloy, Ag, or the like is applied to both main surfaces of the piezoelectric ceramic body 1 and subjected to a baking treatment at a predetermined temperature (for example, 750 ° C. to 850 ° C.). 2a and 2b are formed.

  Thereafter, a polarization process is performed by applying a predetermined electric field for a predetermined time in an insulating oil such as silicon oil heated to a predetermined temperature (for example, 80 ° C.), whereby a laminated piezoelectric actuator is manufactured.

  The external electrodes 2a and 2b may be formed by a thin film forming method such as a sputtering method or a vacuum vapor deposition method as long as the adhesion is good.

  As described above, the laminated piezoelectric actuator has a high orientation because the piezoelectric ceramic layer is formed of the ceramic sintered body. Therefore, the laminated piezoelectric actuator has a large electromechanical coupling coefficient and a good electrical characteristic compared to the conventional one. A piezoelectric actuator can be obtained.

  The present invention is not limited to the above embodiment. For example, the ceramic sintered body may contain a trace amount of inevitable impurities such as Hf, Ca, Al, and Si in the manufacturing process, but it does not affect the orientation and piezoelectric characteristics.

  In addition, the multilayer piezoelectric actuator described above is also an example for the piezoelectric ceramic electronic component, and it is needless to say that the piezoelectric ceramic electronic component can be widely applied to a single plate type piezoelectric component and other piezoelectric components using piezoelectricity other than the multilayer piezoelectric actuator.

  Next, examples of the present invention will be specifically described.

[Sample preparation]
With respect to various rare earth elements used for the second subcomponent, the relationship between the element type and the degree of orientation was examined.

First, as ceramic raw materials, Pb ₃ O ₄ , TiO ₂ , ZrO ₂ , Nb ₂ O ₅ containing Nb (first subcomponent), NiO containing Ni (third subcomponent) are prepared, Furthermore, La ₂ O ₃ , CeO ₂ , Pr ₆ O ₁₁ , Nd ₂ O ₃ , Eu ₂ O ₃ , Gd ₂ O ₃ , Tb ₂ O ₃ , Dy ₂ O ₃ , Ho ₂ O ₃ as rare earth oxides, Er ₂ O ₃ , Tm ₂ O ₃ , Yb ₂ O ₃ , and Lu ₂ O ₃ were prepared.

  Then, these ceramic raw materials are weighed so that the element content after sintering is as shown in Table 1, and such a weighed product is put into a ball mill together with pure water as a solvent and PSZ balls as a grinding medium, Mix and stir for 15 hours in a ball mill.

  Next, this mixture was dried, calcined at a temperature of 1000 ° C., and then dry-pulverized to obtain a ceramic raw material powder (composite).

  Next, 1.5 parts by weight of a dispersant and 40 parts by weight of pure water were added to 25 g of the ceramic raw material powder, and mixed and ground in a ball mill for 8 hours in the presence of PSZ balls to obtain a ceramic slurry.

  Next, these ceramic slurries were formed while applying a magnetic field of 1 to 9 T, thereby producing a ceramic molded body.

  Subsequently, this ceramic molded body was fired in an oxygen atmosphere at a maximum firing temperature of 1100 ° C. for 3 hours to prepare samples (ceramic sintered bodies) of sample numbers 1 to 14.

(Sample evaluation)
<Composition analysis>
Elemental analysis of each sample of sample numbers 1 to 14 was performed, and the content of the element in each sample was determined.

  First, the elements contained in the sample were identified using the XRF method, and the approximate content was measured. Next, each sample was pulverized in a mortar, and the obtained powder was dissolved in nitric acid to form a solution, and the content of the element contained in the solution sample was determined using the ICP-AES method.

  When the crystal structure of each sample was examined using an XRD apparatus, it was confirmed that the sample had an oxide structure. Therefore, components other than elements detected by the ICP-AES method in the sample were oxygen. I thought.

<Orientation degree>
About sample numbers 1-14, it cut | disconnected in the surface which makes the application direction of a magnetic field a normal line. Subsequently, an XRD apparatus (characteristic X-ray: CuKα ray) was used, and an X-ray diffraction spectrum of a plane (T plane) perpendicular to the cut surface was measured within a diffraction angle 2θ of 15 to 65 °.

  FIG. 2 is a diagram showing an example of the measurement result of the X-ray diffraction spectrum, and shows the case of the sample number 9. FIG. 2A is an X-ray diffraction spectrum of a non-oriented sample to which no magnetic field is applied, and FIG. 2B is an X-ray diffraction spectrum when a 3T magnetic field is applied. In the figure, the horizontal axis represents the diffraction angle 2θ (°), and the vertical axis represents the X-ray intensity (a.u.).

As is apparent from FIG. 2B, X-ray peak intensities of the (001) plane and (100) plane appear when the diffraction angle 2θ is 21 to 23 °, and (101) when the diffraction angle 2θ is 30 to 32 °. The X-ray peak intensity of the (110) plane appears, and the X-ray peak intensity of the (111) plane appears when the diffraction angle 2θ is 38 to 39 °. And these X-ray peak intensities were set to I (001), I (100), I (101), I (110), and I (111) in order. Similarly, with respect to the non-oriented sample shown in FIG. 2A, the X-ray peak intensities are sequentially set to I ₀ (001), I ₀ (100), I ₀ (101), I ₀ (110), I ₀ ( 111).

  And, as described in the section of [Embodiment for carrying out the invention], since the degree of orientation F by the Lotgering method is expressed by Formula (1), as shown by Formula (1 ′), these X The line peak intensity was substituted into Equation (1), and the degree of orientation F was determined.

<Measurement results>
Table 1 shows the content (wt%) of the elements detected by the ICP-AES method and the degree of orientation F of the samples Nos. 1 to 14. Since it was confirmed that each sample had an oxide structure as described above, it was considered that the contained components other than the elements detected by the ICP-AES method were oxygen. The degree of orientation F is shown in terms of “%”.

  Since Sample No. 1 did not contain the second subcomponent, the degree of orientation F was 44% even when a 3T magnetic field was applied, indicating that the crystal orientation was poor.

  Sample Nos. 2, 4-7, and 12-14 contain La, Pr, Nd, Eu, Gd, Tm, Yb, Lu and rare earth elements outside the scope of the present invention as the second subcomponent. Although the content is 0.05 wt% or more, even when a 3T magnetic field is applied, the orientation degree F is 19 to 49%, which is less than 50%, and it was found that the crystal orientation is inferior.

  On the other hand, sample numbers 3 and 8 to 11 contain Ce, Tb, Dy, Ho, and Er within the range of the present invention in the range of 1.31 to 1.58 wt%. That is, since the rare earth element within the scope of the present invention is contained in an amount of 0.05 wt% or more, the orientation degree F is 58 to 82% when a magnetic field of 3 T is applied, and it has been found that the film has good orientation.

  FIG. 3 shows the relationship between the rare earth element and the degree of orientation. The horizontal axis represents the element type of the rare earth element, and the vertical axis represents the orientation degree F (%). In the figure, a case is shown in which magnetic fields of 1T for ♦, 3T for □, 5T for Δ, and 9T for ● are applied.

  As is apparent from FIG. 3, Ce, Tb, Dy, Ho, and Er within the scope of the present invention have a good degree of orientation F. When a magnetic field of 9T is applied, the orientation degree F is extremely large as 74 to 82%. It has gained. In particular, among these rare earth elements within the scope of the present invention, Dy and Tb have an orientation degree F of 50% or more even when the applied magnetic field is 1 T, and it was found that they are more preferable.

  In contrast, La, Pr, Nd, Eu, Gd, Tm, Yb, and Lu outside the scope of the present invention are inferior in orientation.

  From the above, it has been found that the second subcomponent is not limited to a rare earth element, but is preferably selected from Ce, Tb, Dy, Ho, and Er among the rare earth elements.

  The characteristics were evaluated by varying the contents of Nb and Sb as the first subcomponent, and the effects of adding the second and third subcomponents were also examined.

First, as ceramic raw _{materials, Pb 3 O 4, TiO 2} , ZrO 2, Nb containing _{Nb 2 O 5, Sb 2 O} 3 containing the Sb, Dy _Dy 2 O containing a (second subcomponent) _3. NiO containing Ni (third subcomponent) was prepared. Next, these ceramic raw materials were weighed so that the element content after sintering was as shown in Table 2.

  Thereafter, samples Nos. 21 to 26 were prepared and analyzed by the same method and procedure as in Example 1, and the degree of orientation was obtained.

  Table 2 shows the element content (wt%) and the orientation degree F of each sample of sample numbers 21 to 26.

  As in Example 1, components other than the elements detected by the ICP-AES method are regarded as oxygen, and the degree of orientation F is shown in terms of “%”.

  Sample Nos. 21 and 25 have low Nb contents of 0.036 wt% and 0.041 wt% and do not contain the second subcomponent, so that the applied magnetic field is not oriented at 1 T, and a 3 T magnetic field is applied. Even when applied, the degree of orientation F was 17% and 8%, indicating that the crystal orientation was extremely inferior.

  In Sample No. 22, the content of Dy as the second subcomponent is 1.54 wt%, but since the content of Nb is as low as 0.041 wt%, the degree of orientation is maintained even when a magnetic field of 3 to 9 T is applied. F was 24 to 30%, and it was found that the crystal orientation was inferior.

  Sample No. 23 has Nb contents of 0.613 wt% and 0.6 wt% or more, but since the second subcomponent is not contained, the orientation degree F is not changed even when a magnetic field of 3 to 5 T is applied. It was 12-30%, and it turned out that it is inferior to crystal orientation.

  In contrast, Sample No. 24 has a Nb content of 0.628 wt%, and Sample No. 26 has a total content of Nb and Sb of 0.756 wt%, both containing 0.6 wt% or more. In addition, the Dy content is 1.50 wt% for sample number 24 and 1.44 wt% for sample number 26, both of which are 0.05 wt% or more, so even when a 3T magnetic field is applied, The degree was 56 to 63%, and it was found that good orientation was imparted.

  From the above, the content of the first subcomponent (Nb, Sb) needs to be 0.6 wt% or more, but even if only the first subcomponent is contained, the desired orientation cannot be imparted, It has been found that by including both the first subcomponent and the second subcomponent, good orientation can be imparted by these synergistic effects.

  In addition, sample number 24 containing Ni as the third subcomponent was able to increase the degree of orientation F compared to sample number 26 containing no Ni. That is, it has been found that the orientation can be further improved by containing the third subcomponent.

  Dy was used as the second subcomponent, and the characteristics were evaluated by varying the content of Dy.

That is, Pb ₃ O ₄ , TiO ₂ , ZrO ₂ , Nb ₂ O ₅ , Dy ₂ O ₃ , and NiO were prepared as ceramic raw materials. Next, these ceramic raw materials were weighed so that the element content after sintering would be as shown in Table 3.

  Thereafter, samples Nos. 31 to 33 were prepared by the same method and procedure as in Example 1, subjected to composition analysis, and the degree of orientation was obtained.

  Table 3 shows the element content (wt%) and the degree of orientation F of each sample of sample numbers 31 to 33. In Table 3, Sample No. 1 not containing Dy and Sample No. 9 having a Dy content of 1.50 wt% are shown again.

  As in Example 1, components other than the elements detected by the ICP-AES method are regarded as oxygen, and the degree of orientation F is shown in terms of “%”.

  Sample Nos. 31 to 33 have a Dy content of 0.05 to 0.50 wt%, and when a 3T magnetic field is applied, the degree of orientation is 62 to 72%, and good orientation can be imparted. I understood.

  That is, if the second subcomponent such as Dy is contained in an amount of 0.05 wt% or more, a ceramic sintered body imparted with a high orientation in combination with the effect of adding a predetermined amount of the first subcomponent. It turns out that it is obtained.

  FIG. 4 is a diagram showing the relationship between the magnitude of the applied magnetic field and the degree of orientation. The horizontal axis represents the magnetic field (T), and the vertical axis represents the orientation degree F (%). In the figure, the ● mark indicates the sample number 1, the x mark indicates the sample number 31, the Δ mark indicates the sample number 32, the □ mark indicates the sample number 33, and the ◆ mark indicates the sample number 9.

  As can be seen from FIG. 4, the degree of orientation F increases as the Dy content increases.

  Next, the orientation orientation of sample number 31 was analyzed using the EBSD method.

  That is, Sample No. 31 was cut and its cross section was polished, and an electron beam narrowly focused on the cut surface was irradiated from an oblique direction, and an electron beam Kikuchi pattern was obtained by backward scattering. And this Kikuchi pattern was analyzed and the crystal orientation of the location where the electron beam collided with the sample was specified. This was observed by SEM over a wide range including a large number of crystal grains of 100 to 1000, analyzed using the EBSD method, and the distribution state of crystal orientation of each crystal grain was examined.

  FIG. 5 is a mapping diagram showing a distribution state of {100} orientation included in a range of 20 ° or less with respect to the application direction of the magnetic field for Sample No. 31.

  Further, the EBSD analysis was performed on the non-oriented sample having the same composition component as the sample number 31 as described above.

  FIG. 6 is a mapping diagram showing the analysis result, and shows the distribution state of {100} orientation included in a range within 20 ° with respect to the magnetic field application direction for the non-oriented sample.

  In FIG. 5 and FIG. 6, crystal grains are shown in white, gray, and black shading, and a crystal in which the portion from black to gray is {100} oriented within a range of 20 ° or less with respect to the magnetic field application direction. Shows particles.

  In the non-oriented sample, as shown in FIG. 6, there are few {100} oriented crystal particles, and the abundance ratio of {100} oriented crystal particles included in a range within 20 ° with respect to the direction of application of the magnetic field is The cross-sectional area ratio was 16.9%.

  On the other hand, as shown in FIG. 5, sample No. 31 has a large number of crystal particles displayed in black to gray and the presence of {100} oriented crystal particles included in a range within 20 ° with respect to the direction of application of the magnetic field. The ratio was 57.4% in terms of the cross-sectional area ratio, and it was confirmed that Sample No. 31 was {100} oriented.

  The characteristics were evaluated by varying the element type and content of the third subcomponent.

Specifically, Pb ₃ O ₄ , TiO ₂ , ZrO ₂ , Nb ₂ O ₅ containing Nb, Sb ₂ O ₃ containing Sb, and Dy ₂ O ₃ containing Dy were prepared as ceramic raw materials. NiO, CoO, Fe ₂ O ₃ , MnO ₂ , MgO, and ZnO containing the subcomponents were prepared.

  Then, these ceramic raw materials are weighed so that the element content after sintering is as shown in Table 4, and then samples Nos. 41 to 55 are prepared by the same method and procedure as in Example 1 for composition analysis. Went.

  Further, the molar content of the subcomponent with respect to 100 mol parts of the main component and the molar ratio of the third subcomponent with respect to the first subcomponent were calculated based on the results of the composition analysis.

  First, the molar amount of each element was calculated by dividing the content of each element obtained by composition analysis by the respective atomic weight. Next, among the molar amount of each element, the total amount of the molar amount of Ti element and the molar amount of Zr element was compared with the molar amount of Pb element, and the larger one was defined as the molar amount of the main component. Then, the sum of the molar amount of elements other than the main component elements (Pb, Ti, Zr) is divided by the molar amount of the main component, multiplied by 100, and the molar content of subcomponents relative to 100 mol parts of the main component Was calculated.

  Further, the molar amount of the third subcomponent was divided by the molar amount of the first subcomponent to calculate the molar ratio between the third subcomponent and the first subcomponent.

  Next, the orientation degree F was determined by the same method and procedure as in Example 1.

  Table 4 shows the element content of each sample of sample numbers 41 to 55, and Table 5 shows the molar ratio between the third subcomponent and the first subcomponent of each sample of sample numbers 41 to 55, the main component 100. The total amount of subcomponents (mole part) and the degree of orientation F relative to the mole part are shown. As in Example 1, components other than the elements detected by the ICP-AES method are regarded as oxygen, and the degree of orientation F is shown in terms of “%”.

  In Sample No. 41, the Nb content is 0.594 wt% and 0.6 wt% or less, the Ni content is 0.185 wt% and 0.29 wt% or less, and the second subcomponent is Since it was not contained, the applied magnetic field was not oriented at 1T, and even when a 3T magnetic field was applied, the orientation degree F was 17%, indicating that the crystal orientation was poor.

  In sample number 42, the Dy content is 0.15 wt% and 0.05 wt% or more, but the Nb content is 0.591 wt% and 0.6 wt% or less, and the Ni content is also 0.161 wt%. Therefore, even when a magnetic field of 3 to 9 T was applied, the degree of orientation F was as low as 24 to 30%, indicating that the crystal orientation was inferior.

  Sample No. 44 has Nb contents of 0.613 wt% and 0.6 wt% or more, but does not contain the second subcomponent, and the content of Co as the third subcomponent is also 0. Therefore, in order to obtain an orientation degree of 50% or more, it was necessary to apply a 9T magnetic field, and with an applied magnetic field of 3-5T, only an orientation degree F of less than 50% was obtained.

  In Sample No. 46, the Nb content is 2.88 wt% and 0.6 wt% or more, and the Fe content as the third subcomponent is 0.86 wt% and 0.29 wt% or more. Thus, it was found that the degree of orientation F was 45% even when a 9T magnetic field was applied, and the orientation was inferior.

  Sample No. 48 has Nb contents of 2.95 wt% and 0.6 wt% or more, and the content of Mn as the third subcomponent is 0.86 wt% and 0.29 wt% or more. 2 was not contained, so that it was not oriented when a magnetic field of 5 T or less was applied, and even when a strong magnetic field of 9 T was applied, the degree of orientation F was 2%, indicating that the orientation was significantly inferior. .

  Sample No. 50 has Nb contents of 2.96 wt% and 0.6 wt% or more, and Mg content as the third subcomponent is 0.86 wt% and 0.29 wt% or more. 2 subcomponents are not contained, and therefore, when the applied magnetic field is 3T or less, the orientation degree F is 40% or less, and in order to obtain the orientation degree F of 50% or more, it is necessary to apply a magnetic field of 5T or more. I found out.

  Sample No. 52 has Nb contents of 2.88 wt% and 0.6 wt% or more, and Zn content as the third subcomponent is also 1.00 wt% and 0.29 wt% or more. 2 is not contained, and therefore when the applied magnetic field is 5T or less, the orientation degree F is less than 50%, and in order to obtain the orientation degree F of 50% or more, it is necessary to apply a magnetic field of 9T or more. I understood that.

  In Sample No. 54, the total content of Nb and Sb as the first subcomponent is 3.858 wt% and 0.6 wt% or more, and the content of Ni as the third subcomponent is also 0.916 wt%. 0.29 wt% or more, but the second subcomponent is not contained. Therefore, when the applied magnetic field is 5 T or less, the orientation degree F is less than 50%, and an orientation degree F of 50% or more is obtained. It was found that it was necessary to apply a strong magnetic field of 9 T or more.

  On the other hand, the sample numbers 43, 45, 47, 49, 51, 53, and 55 have a content of the first subcomponent of 0.994 to 3.745 wt% and 0.6 wt% or more, and contain Dy. The amount is 0.15 to 1.54 wt% and 0.15 wt% or more, and the content of the third subcomponent (Ni, Co, Fe, Mn, Mg, Zn) is 0.29 wt% or more in the present invention. Thus, it was found that the degree of orientation F was as high as 50% or more with an applied magnetic field of 3T.

  In particular, it was found that Sample Nos. 45 and 51 can obtain a high orientation having an orientation degree F of 57 to 63% even when a weak magnetic field of 1 T is applied.

  Sample numbers 43, 45, 47, 49, 51, 53, and 55 described above have a molar ratio of the third subcomponent to the first subcomponent of 0.45 to 0.54. It was found that good orientation could be obtained even when the component contained 5 mol parts or more of subcomponents with respect to 100 mol parts of the main component.

  Using the sample number 9 of the example 1 and the sample number 32 of the example 3, a piezoelectric ceramic electronic component was manufactured.

  That is, with respect to Sample No. 9 and Sample No. 32, a ceramic body having a thickness of 0.85 mm and oriented in the thickness direction is cut by a plane whose normal is the direction in which a magnetic field is applied during molding. did.

  Next, Ag electrodes were formed on both main surfaces of the ceramic body, and then cut into a rectangular shape with a length of 5 mm and a width of 2.2 mm. This ceramic body was subjected to polarization treatment by applying a voltage of 2.3 kV in the thickness direction in silicon oil at 80 ° C. and holding for 10 minutes. Thereafter, the silicon oil was washed and removed to obtain a piezoelectric ceramic electronic component.

Next, the piezoelectric ceramic electronic component, an impedance analyzer (manufactured by Agilent Technologies, 4294A) using a resonance - was measured electromechanical coupling factor k ₃₁ using antiresonance method.

Table 6 shows the electromechanical coupling coefficient k ₃₁ of sample numbers 9 and 32 together with the non-oriented samples (9 ′, 32 ′). The increase factor is for a non-oriented sample.

Sample numbers 9 ′ and 32 ′, which are non-oriented samples, had electromechanical coupling coefficients k ₃₁ of 25.5% and 32.2%, respectively.

On the other hand, Sample Nos. 9 and 32 to which a 3T magnetic field was applied had high orientation degrees F of 87% and 67%, respectively, so that the electromechanical coupling coefficient k ₃₁ was 29.2% and 36.4%. As compared with the non-oriented sample to which no magnetic field was applied, the increasing magnifications were 1.15 times and 1.13 times, respectively.

It was found that by increasing the orientation in this way, a piezoelectric ceramic electronic component having a larger electromechanical coupling coefficient k ₃₁ can be obtained.

  A ceramic sintered body having sufficient crystal orientation can be obtained even when a weak magnetic field is applied compared to the prior art, and a piezoelectric ceramic having a better electromechanical coupling coefficient can be obtained by using this ceramic sintered body. An electronic component can be obtained.

DESCRIPTION OF SYMBOLS 1 Piezoelectric ceramic body 2a, 2b External electrode 3a-3g Internal electrode

Claims (15)

A composite oxide having a perovskite crystal structure represented by the general formula A _m BO ₃ as a main component;
The first subcomponent containing at least one element of Nb and Sb is contained in an amount of 0.6 wt% or more,
A second subcomponent containing at least one element selected from Ce, Tb, Dy, Ho, and Er is contained in an amount of 0.05 wt% or more;
A ceramic sintered body characterized in that specific crystal planes of crystal grains are oriented in a predetermined direction.   A third subcomponent including at least the first and second subcomponents and including at least one element selected from Ni, Fe, Co, Mn, Mg, and Zn; The ceramic sintered body according to claim 1, wherein the ceramic sintered body is contained in an amount of 29 wt% or more.   3. The ceramic sintered body according to claim 2, wherein the content of the third subcomponent with respect to the content of the first subcomponent is 0.45 to 0.54 in molar ratio.   4. The ceramic sintered body according to claim 1, wherein a total content of subcomponents other than the main component is 5 mol parts or more with respect to 100 mol parts of the main components. 5.   The ceramic sintered body according to any one of claims 1 to 4, wherein the specific crystal plane is a {100} plane.   The ceramic sintered body according to any one of claims 1 to 4, wherein the specific crystal plane is a {100} plane, and an orientation degree by a Lotgering method is 0.5 or more. The specific crystal plane is a {100} plane, and the crystal grains are oriented by applying a magnetic field,
The abundance ratio of the crystal grains in which the {100} planes of the crystal grains are oriented in the predetermined direction within a range of 20 ° with respect to the direction of the magnetic field application is 50% or more in terms of a cross-sectional area ratio. The ceramic sintered body according to any one of claims 1 to 4 or claim 6.   8. The ceramic sintered body according to claim 7, wherein the abundance ratio is calculated based on an analysis result based on an electron beam backscatter diffraction method.   9. The ceramic sintered body according to claim 1, wherein the composite oxide is a lead zirconate titanate compound.   10. The average particle diameter of the crystal particles is 0.5 to 5 μm when a wide field of view including 100 or more of the crystal particles in one visual field is observed with a scanning electron microscope. The ceramic sintered body according to any one of the above. A method for producing a ceramic sintered body containing a composite oxide having a perovskite crystal structure represented by the general formula A _m BO ₃ as a main component, and comprising a plurality of subcomponents,
As a ceramic raw material, a plurality of raw materials containing at least the element as the main component, a raw material containing a first subcomponent containing at least one element of Nb and Sb, Ce, Tb, Dy, Ho And a raw material containing a second subcomponent containing at least one element selected from Er, and a weighing step for weighing these ceramic raw materials,
A synthesis step of producing a composite obtained by synthesizing the ceramic raw material and the first and second subcomponents;
Slurry the composite to produce a ceramic slurry;
Forming a ceramic molded body by applying a molding process while applying a magnetic field to the ceramic slurry; and
A firing step of firing the ceramic molded body,
In the weighing step, the ceramic raw material is weighed so that the contents of the first subcomponent and the second subcomponent are 0.05 wt% or more and 0.6 wt% or more, respectively, after firing. ,
The method for producing a ceramic sintered body characterized in that in the forming body producing step, a magnetic field applied to the ceramic slurry is 9 T or less.   The method for producing a ceramic sintered body according to claim 11, wherein the magnetic field applied to the ceramic slurry is 3 to 5T.   In the weighing step, the third subcomponent after firing the raw material containing the third subcomponent containing at least one element selected from Ni, Fe, Co, Mn, Mg, and Zn. The method for producing a ceramic sintered body according to claim 11, wherein the content of the ceramic sintered body is weighed so that the content is 0.29 wt% or more.   In the forming body preparing step, a hollow electromagnet having an axial direction as a conveying direction of the ceramic slurry is arranged, a magnetic field is applied in an in-plane direction of the ceramic slurry, and the hollow portion of the electromagnet is applied to the ceramic slurry. The method for producing a ceramic sintered body according to any one of claims 11 to 13, wherein the orientation treatment is performed while the material is passed. In a piezoelectric ceramic electronic component in which external electrodes are formed on the surface of a ceramic body having a piezoelectric ceramic layer,
The piezoelectric ceramic electronic component according to claim 1, wherein the piezoelectric ceramic layer is formed of the ceramic sintered body according to any one of claims 1 to 10.