JP2011029537A - Multilayer electronic component and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer electronic component capable of using an internal electrode layer containing Ag as a principal component and Pd having a content ratio of ≤5 mass%, and capable of inhibiting time degradation of insulation while exhibiting superior piezoelectricity, and also to provide a method of manufacturing the same. <P>SOLUTION: The multilayer electronic component includes internal electrode layers 3 in a piezoelectric ceramic. The piezoelectric ceramic consists of crystal particles of lead zirconate titanate system crystal containing at least one kind of Sb and Nb, Pb, Zr, Ti, Zn, and Bi, does not substantially contain any amorphous phase and any other crystal phase except the lead zirconate titanate system crystal in the grain boundaries of the crystal particles of the lead zirconate titanate system crystal, and has a density of ≥7.7 g/cm<SP>3</SP>. The internal electrode layers 3 contain Ag as a metal component and as a principal component, and Pd having a content ratio of ≤5 mass%. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a multilayer electronic component and a method for manufacturing the same, and more particularly to a ceramic filter, an ultrasonic applied vibrator, a piezoelectric buzzer, a piezoelectric ignition unit, an ultrasonic motor, a piezoelectric fan, a piezoelectric sensor, a piezoelectric actuator, and the like. The present invention relates to a multilayer electronic component having an internal electrode layer therein and a method for manufacturing the same.

  Piezoelectric actuators using piezoelectric ceramics use displacements and forces generated through piezoelectric phenomena as mechanical drive sources, and are one of the most recently noted in the field of mechatronics. Piezoelectric actuators are solid-state elements that use the piezoelectric effect, so they consume less power, have a faster response speed, have a larger amount of displacement, and generate heat compared to conventional electromagnetic actuators with a coil wound around a magnetic material. It has excellent features such as small amount, small size and weight. For this reason, research and development has been promoted in various fields with the advancement of mechatronics. In recent years, multilayer piezoelectric actuators have been put into practical use for opening and closing fuel injectors for in-vehicle injectors, and are being used as acoustic parts such as autofocus multilayer piezoelectric actuators for cameras and piezoelectric speakers. is there.

By the way, as the use of the above-described piezoelectric actuator is expanded, a laminated piezoelectric actuator that can obtain a larger displacement and generated force at a lower voltage has been widely used. Further, generally the function as a piezoelectric actuator, the piezoelectric strain constant, in particular with d ₃₃ and d ₃₁ constant is desired that as large as possible, insulation is also important not to deteriorate during continuous driving.

As a piezoelectric ceramic composition that meets such a purpose, _the composition formula by molar _{ratio, Pb 1-x-y Sr} x Ba y (Zn 1/3 Sb 2/3) a Zr b Ti 1-a-b O ₃ , x, y, a, b are 0 ≦ x ≦ 0.14, 0 ≦ y ≦ 0.14, 0.04 ≦ x + y, 0.01 ≦ a ≦ 0.12, 0.43 ≦ Those satisfying b ≦ 0.58 are known (for example, see Patent Document 1), and it is described that such a piezoelectric ceramic composition is fired at 1240 to 1300 ° C.

  However, in the piezoelectric ceramic composition described in Patent Document 1, since the firing temperature is as high as 1240 to 1300 ° C., 30% by mass or more of Pd was contained in the ratio of Ag and Pd of the internal electrode. Therefore, as the number of layers increases, there is a disadvantage that the cost is increased and the cost competitiveness is lost, and the use as a displacement element is limited to a very narrow range.

As a piezoelectric ceramic composition that can be fired at a low temperature, PbZrO ₃ —PbTiO ₃ —Pb (Zn _1/3 Sb _2/3 ) O ₃ is a main component, and Bi and Fe elements are contained in an amount of 5 to 15% by mass in terms of BiFeO _3. The piezoelectric ceramic composition fired at 1000 to 1100 ° C. and the main component contains Li, Bi, and at least one of Cd, B, Pb, Si and Zn, and fired at 900 to 1000 ° C. A piezoelectric ceramic composition is known (see Patent Document 2).

JP-A-7-45124 JP 2000-86341 A

  However, although the piezoelectric ceramic composition described in Patent Document 2 can be fired at a low temperature of 1000 ° C. or lower, some of the elements contributing to the low-temperature firing remain at the grain boundaries. In addition, there is a problem in that the insulation gradually deteriorates due to voltage application during driving, leak current increases, and reliability decreases.

  The present invention provides a multilayer electronic component capable of using an internal electrode layer containing Ag as a main component and having a Pd content ratio of 5% by mass or less, being excellent in piezoelectric characteristics, and capable of suppressing deterioration with time of insulation, and a method for manufacturing the same. For the purpose.

The multilayer electronic component of the present invention is a multilayer electronic component having an internal electrode layer in a piezoelectric ceramic, wherein the piezoelectric ceramic includes at least one of Sb and Nb, Pb, Zr, Ti, Zn, and Bi. And crystal grains of the lead zirconate titanate crystal containing the crystal, and the grain boundaries of the crystal grains of the lead zirconate titanate crystal include an amorphous phase and other than the lead zirconate titanate crystal. The crystal phase is substantially absent, the density is 7.7 g / cm ³ or more, the internal electrode layer is mainly composed of Ag as a metal component, and the content ratio of Pd is 5% by mass or less. It is characterized by.

Conventionally, crystal phases other than the amorphous phase and lead zirconate titanate crystal existed at the grain boundaries of the lead zirconate titanate crystal. However, in the present invention, titanic acid can be used even when the internal electrode is mainly composed of Ag as a metal component and the internal electrode having a Pd content ratio of 5% by mass or less is sintered at a low temperature. Since there is substantially no crystal phase other than the lead zirconate-based crystal, it is possible to suppress deterioration over time of the insulation of the piezoelectric ceramic, and since the density is 7.7 g / cm ³ or more, titanic acid in the piezoelectric ceramic Even if there is no crystal phase or amorphous phase other than lead zirconate titanate crystal at the grain boundary of lead zirconate crystal grains, it is fully sintered and piezoelectric characteristics can be improved . Further, since the Pd content ratio is small as the internal electrode layer, an inexpensive multilayer electronic component can be obtained.

  In the multilayer electronic component of the present invention, the metal component of the internal electrode layer is made of Ag. In such a multilayer electronic component, since Pd is not used as the metal component of the internal electrode layer, a cheaper multilayer electronic component can be obtained.

The method for producing a multilayer electronic component according to the present invention includes at least one of Sb and Nb, Pb, Zr, Ti and Zn, and a lead zirconate titanate system in X-ray diffraction measurement using Cukα rays. When the peak intensity of the (101) peak (2θ≈30 °) of the crystal is I ₁ and the peak intensity of the (111) peak (2θ≈38 °) is I ₂ , I ₂ / I ₁ is 0. A step of producing a calcined powder of 130 to 0.160 and a slurry produced by adding and mixing Bi ₂ O ₃ powder to the calcined powder are formed into a sheet shape to produce a green sheet. Forming an internal electrode pattern by applying an internal electrode paste containing Ag as a main component and a Pd content ratio of 5 mass% or less to the green sheet; and forming the internal electrode pattern Glee A step of preparing a molded laminate sheets by stacking a plurality of, by the laminated molded body is fired at nine hundred and twenty to nine hundred and sixty ° C. in air, a solid solution of Bi ₂ O ₃ in the lead zirconate titanate crystals A laminate having an internal electrode layer in a piezoelectric ceramic composed of crystal grains of lead zirconate titanate crystal containing at least one of Sb and Nb and Pb, Zr, Ti, Zn and Bi is manufactured. And a process.

In such a method of manufacturing a multilayer electronic component, even when fired at a low temperature of 920 to 960 ° C., Bi ₂ O ₃ forms a liquid phase, wets the crystal grains of the lead zirconate titanate crystal, Since the diffusion and the grain growth are promoted, the sinterability can be improved, and after sintering, an appropriate amount of Bi ₂ O ₃ can be solid-solved in the lead zirconate titanate crystal. It consists of crystal grains of lead zirconate titanate crystals, and the grain boundaries of the crystal grains of lead zirconate titanate crystals are substantially free of amorphous phases and crystal phases other than lead zirconate titanate crystals. A multilayer electronic component that does not exist can be easily obtained.

In the multilayer electronic component of the present invention, the lead zirconate titanate crystal even when fired at a low temperature such as sintering an internal electrode containing Ag as a main component and having a Pd content of 5% by mass or less. Since there is substantially no crystal phase other than the above, it is possible to suppress deterioration over time of the insulation of the piezoelectric ceramic, and since the density is 7.7 g / cm ³ or more, the lead zirconate titanate crystal in the piezoelectric ceramic Even if there is no crystal phase or amorphous phase other than the lead zirconate titanate-based crystal at the grain boundary of the crystal grain, it is sufficiently sintered and can improve the piezoelectric characteristics. Since the Pd content ratio is small, an inexpensive multilayer electronic component can be obtained.

It is sectional drawing which shows the multilayer electronic component of this invention. Sample No. in Table 1 Is a graph showing the _I 2 / _{I 1} for 1-5 calcining temperature Sample No. in Table 1 It is a figure which shows the X-ray-diffraction measurement result of the calcining powder at the time of changing the calcining temperature of 1-5. Sample No. 3 is a graph showing the bulk density of the laminate with respect to the firing temperature. Sample No. It is a figure which shows the X-ray-diffraction measurement result of 1. Sample No. FIG. 3 is a diagram showing the results of X-ray diffraction measurement of No. 3. Sample No. It is a graph showing the piezoelectric strain constant d ₃₃ for the third firing temperature.

  As shown in FIG. 1, the multilayer electronic component of the present invention has an internal electrode layer in a piezoelectric ceramic. In other words, the piezoelectric body layer 1 and the internal electrode layer 3 are alternately stacked to form a multilayer body. 5 is configured, and a plurality of internal electrode layers 3 are formed in the piezoelectric ceramic. The internal electrode layers 3 are alternately connected by external electrodes 7 formed on both end faces of the laminate 5.

The piezoelectric ceramic is composed of crystal grains of lead zirconate titanate crystal (hereinafter sometimes referred to as PZT crystal) containing at least one of Sb and Nb and Pb, Zr, Ti, Zn, and Bi. At the grain boundaries of the PZT crystal grains, there is substantially no crystal phase other than the amorphous phase and the PZT crystal, and the density is 7.7 g / cm ³ or more.

  Regarding the point that the amorphous phase or the crystal phase other than the PZT crystal does not substantially exist at the grain boundary of the crystal grain of the PZT crystal, the fracture surface or mirror surface of the piezoelectric ceramic is analyzed by energy dispersive X-ray spectroscopy (EDS). ), Or Bi-rich parts constituting a heterogeneous phase at the grain boundaries (interfacial grain boundaries, triple points) of crystal grains are not found by wavelength dispersive X-ray spectroscopy (WDS) composition analysis and electron diffraction Can be confirmed.

  Further, the fact that there is substantially no crystal phase other than the PZT crystal at the grain boundary of the crystal grain of the PZT crystal means that no different phase is seen in the lattice image of the grain boundary with a transmission electron microscope (TEM). Alternatively, in the X-ray diffraction measurement using the Cukα ray of the piezoelectric ceramic cross section, it can be confirmed from the point that a peak due to a crystal other than the PZT crystal peak does not substantially exist.

  In the X-ray diffraction measurement using Cukα rays, the fact that there are substantially no peaks due to crystals other than the PZT crystal peak means that when the (111) peak intensity of the PZT crystal is 100, the PZT system This is the case where the peak intensity other than the crystal is 3 or less. As shown in FIG. 5, the peak intensity is expressed by the length to the peak in the direction perpendicular to the tangent line drawn on both sides of the peak.

The piezoelectric ceramic contains at least one of Sb and Nb and Pb, Zr, Ti, Zn and Bi, and at least one of Sb and Nb as a metal component, Pb, Zr, Ti, Sr, Ba , Zn, and Bi, and a composition formula based on a molar ratio of these metal elements is Pb _1-xyz Sr _x Bay B _{i z} (Zn _1/3 α _2/3 ) _When expressed as _a Zr _b Ti _1- abO ₃ , x, y, z, a, b are 0 ≦ x ≦ 0.14, 0 ≦ y ≦ 0.14, 0 <z ≦ 0.015 , 0.04 ≦ x + y, 0.01 ≦ a ≦ 0.12, and 0.43 ≦ b ≦ 0.58 are desirable. α is at least one of Sb and Nb.

Here, the reason why x, y, z, a, and b are set in the above ranges will be described. The reason why the substitution amount x of Pb with Sr is set to 0 ≦ x ≦ 0.14 is that the Curie temperature can be kept high by substituting a part of Pb with Sr. The reason why the substitution amount y of Pb with Ba is set to 0 ≦ y ≦ 0.14 is that the Curie temperature can be kept high by substituting a part of Pb with Ba, and a high piezoelectric strain constant d ₃₃ can be obtained. Because it can.

Furthermore, if the substitution amount z of Pb by Bi is set to 0 <z ≦ 0.015, within this range, Bi ₂ O ₃ forms a liquid phase at the time of firing, and wets the crystal grains of the PZT crystal, This is because the sinterability can be improved and, after sintering, Bi ₂ O ₃ is dissolved in the PZT-based crystal and the piezoelectric characteristics can be improved.

Also, the reason why the substitution amount a of Ti with (Zn _1/3 α _2/3 ) is set to 0.01 ≦ a ≦ 0.12 is that a large piezoelectric strain constant d ₃₃ and piezoelectric output constant g ₃₃ are obtained. This is because the temperature can be kept high and the dielectric loss can be kept small. When the piezoelectric ceramic composition of the present invention is used as a piezoelectric actuator, a large piezoelectric strain constant can be obtained by setting 0.05 ≦ a ≦ 0.12, and when it is used as a piezoelectric sensor, 0.01 ≦ By setting a ≦ 0.05, a large piezoelectric output constant g ₃₃ can be obtained.

A piezoelectric ceramic composition mainly composed of PZT has an MPB (composition phase boundary) showing a maximum value of the piezoelectric strain constant when the solid solution ratio of PbZrO ₃ and PbTiO ₃ is changed. As the piezoelectric actuator material, the MPB and the composition value in the vicinity thereof are used. Since this MPB varies depending on the amounts of x and a, the value of b is set to a composition range in which MPB can be captured within the composition range of x and a.

The density of the piezoelectric ceramic is 7.7 g / cm ³ or more. In particular, 7.8 g / cm ³ or more is desirable. In the present invention, the bulk density of the laminate is the density of the piezoelectric ceramic.

In the multilayer electronic component of the present invention, the internal electrode layer is mainly composed of Ag as a metal component, and the content ratio of Pd is 5% by mass or less. In particular, the metal component is preferably made of Ag. The internal electrode layer containing Ag as a main component and having a Pd content of 5% by mass or less must be fired at 920 to 960 ° C., so that the piezoelectric ceramic is also sintered at 920 to 960 ° C., and the density of the piezoelectric ceramic is It needs to be 7.7 g / cm ³ or more. Ceramic particles may be present as the internal electrode layer.

The multilayer electronic component configured as described above can be manufactured as follows. First, in the X-ray diffraction measurement using at least one of Sb and Nb and Pb, Zr, Ti, and Zn and using Cukα rays, the (101) peak (2θ≈ the peak intensity of 30 °) and _{I 1,} when the the _{I 2} peak intensity of the peak (2 [Theta] ≒ 38 °) of _(111), calcined powder I 2 / _{I 1} is from 0.130 to 0.160 Is made.

Specifically, for example, PbO, ZrO ₂ , TiO ₂ , SrCO ₃ , BaCO ₃ , ZnO, Sb ₂ O ₃ , and Nb ₂ O ₅ powders are weighed and mixed as raw materials, and then this mixture is dehydrated and dried. And calcining at 850 to 950 ° C. for 1 to 3 hours. After calcination, I ₂ / I ₁ was adjusted to 0.130 to 0.160. Again ground in a ball mill or the like, for example, the average particle diameter _{D 50} is set to be in the range of 0.5～0.7Myuemu.

The reason why I ₂ / I ₁ was set to 0.130 to 0.160 is that if I ₂ / I ₁ is in the range of 0.130 to 0.160, the sinterability is improved by adding Bi ₂ O ₃ , As the synthesis of lead zirconate titanate crystals progresses, Bi ₂ O ₃ is taken into the lead zirconate titanate crystals at the same time as the grain growth accompanying sintering, and in the sintering temperature range of 920 to 960 ° C. This is because the phase component does not remain and is sintered. On the other hand, when I ₂ / I ₁ is smaller than 0.130, the synthesis of lead zirconate titanate crystals is insufficient, and even if Bi ₂ O ₃ powder is added and fired, the sinterability is reduced. This is because it cannot be improved. In addition, when I ₂ / I ₁ is larger than 0.160, the synthesis of lead zirconate titanate-based crystals proceeds too much, and even if Bi ₂ O ₃ powder is added and baked, it is dissolved in the crystals. Because it becomes difficult.

Here, as an index representing the synthesis degree of the lead zirconate titanate crystal, the peak intensity I ₁ of the peak (2θ≈30 °) of the lead zirconate titanate crystal (2θ≈30 °), the peak (2θ) The reason why the peak intensity I ₂ of ≈38 ° is used is that the peak position and pattern shape of other peaks change as the crystal phase changes depending on the calcining temperature. This is because the 2θ≈30 ° and the peak of (111) (2θ≈38 °) are not so, and are considered optimal for expressing the degree of synthesis.

Thereafter, for example, Bi ₂ O ₃ powder having a D ₅₀ of 0.5 to 0.7 μm and a binder are added to and mixed with the calcined powder, and then a green sheet is produced by a doctor blade method. The amount of Bi ₂ O ₃ powder added is the same as the amount of Bi added to the calcined powder. The amount of Bi ₂ O ₃ powder expressed by the chemical formula of ABO ₃ is the A-site Pb _1-xyz sr _x Ba of the lead zirconate titanate crystal. _y Bi moles of Bi when expressed in a composition notation _z may be desirable to add a _Bi 2 _{O 3} amount less, which corresponds to 0.015 moles.

  On the other hand, an internal electrode paste having a main component of Ag as a metal component and a Pd content ratio of 5% by mass or less is prepared. Ceramic particles may be mixed as a common material in the internal electrode paste.

  This internal electrode paste is applied to a green sheet to form an internal electrode pattern.

A plurality of green sheets on which the internal electrode patterns are formed are stacked, and finally, green sheets on which the internal electrode patterns are not formed are stacked to produce a stacked molded body. Bake at ℃. Accordingly, Bi ₂ O ₃ is dissolved in a lead zirconate titanate crystals in the piezoelectric ceramic.

In such a method of manufacturing a multilayer electronic component, even when fired at a low temperature of 920 to 960 ° C., Bi ₂ O ₃ forms a liquid phase, wets the crystal grains of lead zirconate titanate crystal, and sinterability In addition, after sintering, Bi ₂ O ₃ is almost completely dissolved in the lead zirconate titanate crystal, so that the piezoelectric ceramic is composed of crystal grains of lead zirconate titanate crystal and titanium. There is substantially no crystal phase other than the amorphous phase and the lead zirconate titanate crystal at the grain boundary of the lead zirconate acid crystal, so that the piezoelectric characteristics can be improved.

Conventionally, Li, B, or the like that forms a liquid phase has been added to perform low-temperature firing, and low-temperature firing is possible, but at the grain boundaries of the PZT crystal grains, other than amorphous phases and PZT crystals There was a crystal phase, and the insulation resistance decreased with time, and the piezoelectric characteristics decreased. In the present invention, Bi ₂ O ₃ forming a liquid phase is used, and a liquid phase is formed at the time of firing to improve the sinterability, and a density of 7.7 g / cm ³ or more can be obtained. The solid phase is almost completely dissolved in the PZT crystal, and there is no amorphous phase or crystal phase other than the PZT crystal at the grain boundary of the PZT crystal grain, so that the piezoelectric characteristics can be improved. As a result, the insulation resistance value of the piezoelectric ceramic becomes 100 MΩ or more at 85 ° C., and insulation deterioration during continuous driving can be suppressed.

The invention will now be illustrated by the following examples. PbO, ZrO ₂ , TiO ₂ , SrCO ₃ , BaCO ₃ , ZnO, Sb ₂ O ₃ , and Nb ₂ O ₅ powders were used as raw material powders, weighed to the compositions a to h in Table 1, and 24 using a ball mill. Wet mixed for hours. Next, after dehydrating and drying the mixture, the mixture was calcined at the calcining temperature shown in Table 1 for 3 hours, and the calcined material was wet-ground again with a ball mill for 24 hours, and the D ₅₀ was 0.5 to 0.7 μm. A baked powder was obtained. With respect to this calcined powder, the peak intensity of the (101) peak (2θ≈30 °) of the lead zirconate titanate-based crystal in the X-ray diffraction measurement using the Cukα ray is I _1, and the peak of (111) (2θ When the peak intensity at ≈38 ° is defined as I ₂ , I ₂ / I ₁ was determined and listed in Table 1.

The composition of a in the column of the type of calcined powder in Table 1 is Pb _0.92 Ba _0.07 (Zn _1/3 Sb _2/3 ) _0.105 Zr _0.434 Ti _0.461 O ₃ , The composition of b is Pb _0.925 Ba _0.07 (Zn _1/3 Sb _2/3 ) _0.105 Zr _0.434 Ti _0.461 O ₃ , and the composition of c is Pb _0.915 Ba _0.07. (Zn _1/3 Sb _2/3 ) _0.105 Zr _0.434 Ti _0.461 O ₃ , d has a composition of Pb _0.914 Ba _0.07 (Zn _1/3 Sb _2/3 ) _0.105 The composition of Zr _0.434 Ti _0.461 O ₃ , e is Pb _0.92 Ba _0.07 (Zn _1/3 Nb _2/3 ) _0.105 Zr _0.434 Ti _0.461 O ₃ , f _{composition, Pb 0.92 Ba 0.07 (Zn 1/3} S _{2/3) 0.07 (Zn 1/3 Nb 2/3} ) 0.035 Zr 0.434 Ti 0.461 O 3, the composition of _{g, Pb 0.93 Sr 0.04 Ba 0.02 (} Zn _1/3 Sb _2/3 ) _0.0755 Zr _0.460 Ti _0.465 O ₃ , h has a composition of Pb _0.92 Ba _0.07 (Zn _1/3 Sb _2/3 ) _0.105 Zr _{0 .434} Ti _0.461 O ₃ .

In FIG. 1 to 5, I ₂ / I ₁ with respect to the calcining temperature is described, and in FIG. The X-ray-diffraction measurement result of the calcination powder at the time of changing calcination temperature about 1-5 was described.

Thereafter, Bi ₂ O ₃ powder having a D ₅₀ of 0.5 to 0.7 μm was added in an amount shown in Table 1 (A-site Pb _{1 of} lead zirconate titanate crystal expressed by the chemical formula of ABO _{3. -x-y-z Sr x Ba} y Bi added in an amount corresponding to the number of moles of Bi when expressed in a composition notation _z in terms of _Bi 2 _{O 3),} a doctor blade method by mixing it into an organic binder Thus, a green sheet having a thickness of 30 μm was produced. On this green sheet, an internal electrode paste composed of Ag and Pd and having a Pd content ratio shown in Table 1 was screen-printed, and 15 green sheets on which the internal electrode paste was printed were stacked, and finally the internal electrode A green sheet to which no paste was applied was laminated to produce a laminated molded body.

  After that, it was deburied, fired in the atmosphere for 3 hours at the firing temperature shown in Table 1, cooled, and a laminated body in which internal electrodes were alternately exposed on both end faces was produced. Thereafter, external electrodes were formed on both end faces of the multilayer body, and then polarized to obtain a multilayer piezoelectric actuator as a multilayer electronic component. The thickness of one layer of the piezoelectric layer (thickness between the electrodes) was 25 μm.

  About the bulk density of a piezoelectric ceramic, it calculated | required by the Archimedes method about the laminated body. In FIG. For 3, the bulk density with respect to the firing temperature is shown. In addition, it was investigated whether an amorphous phase exists at the grain boundary of the lead zirconate titanate crystal grains and whether a crystal phase other than the lead zirconate titanate crystal exists.

  As for the presence or absence of an amorphous phase in the piezoelectric ceramic, the fracture surface and mirror surface of the piezoelectric ceramic are amorphous at any three triple points of crystal grains by energy dispersive X-ray spectroscopy (EDS) and electron diffraction. A case where no Bi-rich part constituting the qualitative phase was observed was judged as having no amorphous phase.

  Whether or not there is a crystal phase other than the lead zirconate titanate crystal at the grain boundary of the lead zirconate titanate crystal is determined by the X-ray diffraction measurement using the piezoelectric ceramic Cukα ray. , It was judged that there was no case where there was substantially no peak due to a crystal other than the PZT crystal peak. In FIG. The X-ray diffraction measurement results of No. 1 are shown in FIG. 3 X-ray diffraction measurement results are shown.

  For the deterioration test of the insulation resistance of the piezoelectric ceramic, the initial insulation resistance of the multilayer electronic component was measured by applying a DC electric field of 2 kV / mm to the multilayer electronic component in an 85 ° C. constant temperature bath. It was described in Table 1 together with an insulation resistance value of 85 ° C. after the time.

Regarding piezoelectric characteristics, after polarization, after aging treatment at 100 ° C., using a d ₃₃ meter (applying weak vibration to the laminated piezoelectric body and evaluating the charge generated by the piezoelectric effect), the piezoelectric strain constant of the laminated electronic component described determined table 1 d _33. In addition, in FIG. The piezoelectric strain constant d ₃₃ with respect to the firing temperature of 3 was described.

From Tables 1 and 2, when the bulk density of the laminate is 7.7 g / cm ³ or more, the crystal phase other than the amorphous phase and the PZT crystal does not substantially exist at the grain boundary of the crystal grain of the PZT crystal. In the sample of the present invention in which the internal electrode layer is mainly composed of Ag as a metal component and the content ratio of Pd is 5% by mass or less, the initial insulation resistance of the multilayer electronic component is 3 GΩ or more at 85 ° C. It can be seen that even after 100 hours, the deterioration of the insulation resistance with time is small, the piezoelectric strain constant d ₃₃ is 603 p · m / V or more, and the relative dielectric constant is 3500 or more.

On the other hand, the sample No. of the comparative example in which I ₂ / I ₁ is smaller than 0.130. 1 indicates that the bulk density is small, a crystal phase other than the PZT crystal is present, the initial insulation resistance of the multilayer electronic component is small, and the piezoelectric characteristics are low.

In addition, the sample No. of the comparative example in which I ₂ / I ₁ is larger than 0.160. 5 shows that there are crystal phases other than the amorphous phase and the PZT crystal at the grain boundaries of the PZT crystal grains, the insulation resistance of the multilayer electronic component is small, and the piezoelectric characteristics are low.

Further, the amount of Bi ₂ O ₃ powder added is large, and a comparative sample No. 1 in which a crystal phase other than the PZT crystal exists at the grain boundary of the crystal grain of the PZT crystal. In 8, greater aging of the insulation resistance multilayer electronic component, it can be seen that the piezoelectric strain constant d ₃₃ is low.

DESCRIPTION OF SYMBOLS 1 ... Piezoelectric layer 3 ... Internal electrode layer 5 ... Laminated body 7 ... External electrode

Claims (3)

A laminated electronic component having an internal electrode layer in a piezoelectric ceramic, wherein the piezoelectric ceramic contains at least one of Sb and Nb and Pb, Zr, Ti, Zn and Bi. The crystal grain of the lead zirconate titanate crystal is substantially free from an amorphous phase and a crystal phase other than the lead zirconate titanate crystal. A multilayer electronic component having a density of 7.7 g / cm ³ or more, the internal electrode layer containing Ag as a metal component as a main component, and a Pd content ratio of 5 mass% or less.   The multilayer electronic component according to claim 1, wherein the metal component of the internal electrode is made of Ag. (101) peak (2θ≈30) of lead zirconate titanate-based crystal containing at least one of Sb and Nb, Pb, Zr, Ti and Zn and X-ray diffraction measurement using Cukα ray When the peak intensity of (°) is I ₁ and the peak intensity of the (111) peak (2θ≈38 °) is I ₂ , a calcined powder having I ₂ / I ₁ of 0.130 to 0.160 is obtained. A step of producing, a step of forming a green sheet by forming a slurry obtained by adding and mixing Bi ₂ O ₃ powder to the calcined powder, and forming a green sheet; A step of forming an internal electrode pattern by applying an internal electrode paste containing Ag as a main component and having a Pd content ratio of 5% by mass or less, and laminating a plurality of green sheets on which the internal electrode pattern is formed. A step of preparing, by the laminated molded body is fired at 920-960 ° C. in the air, a solid solution of Bi ₂ O ₃ in the lead zirconate titanate crystals, and at least one of Sb and Nb And a step of producing a laminate having an internal electrode layer in a piezoelectric ceramic composed of crystal grains of lead zirconate titanate crystals containing Pb, Zr, Ti, Zn and Bi. A manufacturing method for multilayer electronic components.

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