JP5585361B2 - Ceramic electronic components - Google Patents

Description

  The present invention relates to a ceramic electronic component in which an external electrode electrically connected to an internal electrode is disposed on a ceramic body in which the internal electrode is disposed in the ceramic.

  Conventionally, in a multilayer ceramic electronic component, external electrodes that are electrically connected to internal electrodes are disposed on both end surfaces of a ceramic body (ceramic sintered body) so that a plurality of internal electrodes overlap with each other via a ceramic layer. It is formed by.

  Such an external electrode is usually formed by applying and baking a conductive paste containing metal powder, glass powder and organic resin on the end face of the ceramic body. Ag, Pd, or the like is used as a material for forming the internal electrode and the external electrode. For example, when Pd is used as the material for forming the internal electrode and Ag is used as the material for forming the external electrode, the rate at which Ag diffuses into Pd and the rate at which Pd diffuses into Ag when the conductive paste is baked. Due to this difference, the rate at which Ag constituting the external electrode diffuses toward the internal electrode increases. As a result, the internal electrode protrudes on the outer surface from which the internal electrode of the ceramic body is drawn out, pushes up the external electrode, and it is easy to form a gap at the joint between the external electrode and the internal electrode. Generally, external electrodes are formed by baking conductive paste, but the metal in the conductive paste moves on the edge of the internal electrode in contact with the conductive paste based on a phenomenon called the so-called Känder effect. The electrode grows so as to protrude to the external electrode side. As a result, it is conceivable that the internal electrode protrudes and pushes up the contact surface with the external electrode, thereby forming a gap at the joint between the external electrode and the internal electrode.

  Therefore, when Ag and Pd are used as the material for forming the internal electrode and the external electrode, when the external electrode is baked, the ratio of Ag contained in the internal electrode is the amount of Ag contained in the conductive paste forming the external electrode. When the ratio is higher than the ratio, the ratio of Ag diffusing from the internal electrode side to the external electrode side increases, and the internal electrode cannot contact the external electrode and may be disconnected. Further, when the proportion of Ag contained in the internal electrode and the proportion of Ag contained in the conductive paste forming the external electrode are approximately the same, the internal electrode side to the external electrode side or the external electrode side to the internal The amount of Ag diffusing to the electrode side becomes insufficient, and there is a risk of causing poor connection between the internal electrode and the external electrode.

  In order to improve the disconnection and connection failure between the internal electrode and the external electrode, it is necessary to increase the ratio of Ag contained in the conductive paste forming the external electrode from the ratio of Ag contained in the internal electrode. However, if the proportion of Ag contained in the conductive paste forming the external electrode is made larger than the proportion of Ag contained in the internal electrode, it is contained in the conductive paste forming the external electrode due to a phenomenon called the above-mentioned Kendall effect. When Ag diffuses on the edge of the internal electrode, there is a possibility that a void is generated in the external electrode, or that the internal electrode pushes up the external electrode and a void is generated between the internal electrode and the external electrode.

  If there is a gap in the external electrode, or if a gap is generated between the internal electrode and the external electrode due to the external electrode being pushed up by the internal electrode, the internal electrode and the external electrode are not sufficiently bonded, so the external electrode is baked. Thereafter, when the plating layer is formed, the plating solution enters from the voids and enters the ceramic sintered body, which may cause deterioration of electrical characteristics and poor moisture resistance.

  Therefore, in order to improve the bonding state between the internal electrode and the external electrode, a chip-type electronic component in which the ratio of the metal component, the glass component, and the voids contained in the external electrode is within a predetermined range has been proposed (for example, Patent Document 1). According to the chip-type electronic component described in Patent Document 1, the external electrode is baked twice or more, thereby stabilizing the structure of the external electrode and joining the conductor layer formed on the electronic component body and the external electrode. I try to increase the sex.

JP 2006-13219 A

  However, in the conventional chip-type electronic component, the ratio of the metal component, the glass component, and the voids contained in the external electrode is adjusted until Ag contained in the conductive paste forming the external electrode diffuses into the internal electrode. Since this is not taken into consideration, there is a problem that the internal electrode pushes up a part of the external electrode, and it is impossible to suppress the formation of a gap between the external electrode or the internal electrode and the external electrode.

  Due to the gap generated in the external electrode and the gap generated between the internal electrode and the external electrode, a dense external electrode cannot be formed, and the external electrode is peeled off from the surface of the sintered body, and the bonding strength between the internal electrode and the external electrode is increased. There was a possibility that it could not be raised sufficiently.

  The present invention has been made in view of the above, and an object of the present invention is to provide a ceramic electronic component that increases the bonding strength between an internal electrode and an external electrode and obtains a dense external electrode.

  In order to solve the above-described problems and achieve the object, the present inventors have intensively studied ceramic electronic components. As a result, crystallized glass is used as the glass component included in the external electrode, and the ratio of the metal component included in the external electrode and the ratio of the glass component and the void are within predetermined ranges in terms of the area ratio of the cross section. Thus, it was found that the bonding strength between the internal electrode and the external electrode can be increased and a dense external electrode can be formed. The present invention has been completed based on such knowledge.

The ceramic electronic component of the present invention includes a ceramic body, an internal electrode provided at least inside the ceramic body, including at least Pd, provided on an end surface of the ceramic body, and containing Ag and Pd as metal components. In order to form a metal component contained in the external electrode on the end face of the ceramic body, the glass component includes crystallized glass as a glass component and has a pair of external electrodes that are electrically connected to the internal electrode. Formed by applying a conductive paste containing a metal powder and a glass powder for forming a glass component contained in the external electrode, and a ratio a of the metal component and a ratio b of crystallized glass and voids The area ratio of the cross section at the joint portion with the internal electrode satisfies the following formulas (1) and (2).
86% ≦ a ≦ 97% (1)
3% ≦ b ≦ 14% (2)

  According to this configuration, since crystallized glass is used as the glass component, the viscosity of the crystallized glass does not greatly decrease even when the crystallized glass exceeds the softening point Ts during baking, so the crystallized glass exists as a solid. be able to. For this reason, crystallized glass can inhibit contact between metals contained in the conductive paste forming the external electrode, and can suppress diffusion of Ag contained in the conductive paste forming the external electrode. Further, by setting the ratio a of the metal component of the external electrode and the ratio b of the crystallized glass and voids within the above range in terms of the cross-sectional area ratio, Ag contained in the conductive paste forming the external electrode is reduced. Diffusion to the internal electrode can be suppressed, and the internal electrode can be prevented from pushing up part of the external electrode. For this reason, the generation | occurrence | production of the space | gap which generate | occur | produces in the external electrode or the space | interval between an internal electrode and an external electrode can be suppressed effectively, a precise | minute external electrode can be formed, and the joining strength of an internal electrode and an external electrode is raised. be able to.

  As a preferred embodiment of the present invention, it is preferable that the content of Ag contained in the external electrode is larger than the content of Ag contained in the internal electrode. As a result, it is possible to suppress the diffusion of Ag from the internal electrode side to the external electrode side, so that the internal electrode cannot contact the external electrode and is disconnected, or a connection failure occurs between the internal electrode and the external electrode. Can be suppressed.

  As a preferred embodiment of the present invention, the internal electrode preferably does not contain a glass component. As a result, a dense internal electrode can be formed, and the connectivity with the external electrode can be further improved.

  According to the present invention, it is possible to increase the bonding strength between the internal electrode and the external electrode and obtain a dense external electrode.

FIG. 1 is a perspective view showing a preferred embodiment of a ceramic electronic component according to this embodiment. 2 is a cross-sectional view taken along the line AA in FIG. FIG. 3 is a diagram showing evaluation criteria for the bondability between the internal electrode and the external electrode.

  DESCRIPTION OF EMBODIMENTS Hereinafter, modes for suitably carrying out the present invention (hereinafter referred to as embodiments) will be described in detail. In addition, this invention is not limited by the content described in the following embodiment and an Example. In addition, constituent elements in the embodiments and examples described below include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. Furthermore, the constituent elements disclosed in the embodiments and examples described below may be appropriately combined or may be appropriately selected and used.

  FIG. 1 is a perspective view showing a preferred embodiment of a ceramic electronic component according to this embodiment, and FIG. 2 is a cross-sectional view taken along line AA in FIG. As shown in FIG. 1, the ceramic electronic component 10 includes a ceramic body 11 and a pair of terminal electrodes (external electrodes) 12 formed on both ends of the ceramic body 11. The ceramic body 11 is a laminated varistor, and is formed in a substantially rectangular parallelepiped shape having an upper surface, a lower surface, and four side surfaces. In the present embodiment, the length direction of the ceramic body 11 is X, the width direction is Y, and the thickness direction is Z.

  In the present embodiment, the “substantially rectangular parallelepiped shape” is not only a cubic shape or a rectangular parallelepiped shape, but also a ridge portion of the rectangular parallelepiped is chamfered like a ceramic body 11, and the ridge portion has an R shape. Needless to say, it includes a shape. That is, the ceramic body 11 only needs to have a substantially cubic shape or a rectangular parallelepiped shape.

  The ceramic body 11 includes an end face 13a and an end face 13b (hereinafter, collectively referred to as “end face 13”) facing each other, and a side face 14a and a side face 14b (hereinafter collectively referred to as “end face 13” perpendicular to the end face 13). And a side surface 15a and a side surface 15b (hereinafter sometimes collectively referred to as “side surface 15”) that are perpendicular to the end surface 13 and face each other. The side surface 14 and the side surface 15 are perpendicular to each other.

  The ceramic body 11 includes a ridge portion R13 between the end surface 13 and the side surface 14a, a ridge portion R14 between the end surface 13 and the side surface 14b, a ridge portion R15 between the end surface 13 and the side surface 15a, and an end surface 13 and the side surface 15b. A ridge portion R16 between the side surface 14a and the side surface 15a, a ridge portion R34 between the side surface 15a and the side surface 14b, a ridge portion R35 between the side surface 14b and the side surface 15b, and a side surface 15b. And a ridge R36 between the side surface 14a. The ridges R13 to R16 and R33 to R36 are portions where the ceramic body 11 is polished to form an R shape. The ceramic body 11 having an R shape can suppress the occurrence of breakage in the ridges R13 to R16 and R33 to R36 of the ceramic body 11.

  The ceramic body 11 has a plurality of ceramic layers 21 and a plurality (for example, about 100 layers) of internal electrodes 22. The ceramic body 11 is formed by alternately laminating a plurality of ceramic layers 21 and a plurality of internal electrodes 22. The ceramic body 11 is formed by laminating a plurality of ceramic green sheets (unfired ceramic sheets), and by thermocompression bonding and laminating a laminated body containing a predetermined pattern of conductive paste to be the internal electrodes 22 between the ceramic green sheets. It is a substantially rectangular parallelepiped sintered body obtained by cutting, degreasing and firing. The stacking direction of the ceramic layer 21 and the internal electrode 22 is the thickness direction Z of the ceramic body 11. For convenience of explanation, in FIG. 2, the number of laminated layers of the ceramic layers 21 and the internal electrodes 22 is set to a level that can be visually recognized. You may change suitably. For example, the ceramic layer 21 and the internal electrode 22 may be several tens of layers, or about 100 to 500 layers. Further, the actual ceramic body 11 may be integrated to such an extent that the layers of the ceramic layer 21 cannot be visually recognized.

  The ceramic layer 21 is obtained by firing a ceramic green sheet. The ceramic material constituting the ceramic layer 21 is not particularly limited, and examples thereof include zinc oxide (ZnO), calcium titanate, strontium titanate, and barium titanate (BaTiO3). The ceramic layer 21 may be used by mixing one or more of these ceramic materials.

  One end of the internal electrode 22 is exposed from one of the end faces 13 a and 13 b of the ceramic body 11, is connected to one external electrode 12, the other end is an open end, and is insulated from the other external electrode 12. Has been. The internal electrodes 22 respectively connected to the pair of opposed external electrodes 12 are alternately opposed to each other via the ceramic layer 21, and a plurality of layers are laminated at a predetermined interval.

  As a metal component constituting the internal electrode 22, at least Pd is used, and Ag may be further included. The content of Pd contained in the internal electrode 22 is greater than 0 and 100% or less. As the metal component constituting the internal electrode 22, any conductive material that is usually used as an internal electrode of a ceramic electronic component can be used. However, in the present embodiment, the internal electrode 22 only needs to contain Pd, Ag or another metal such as Ni may be included as a conductive material.

  Moreover, it is preferable that the internal electrode 22 contains only a metal component and does not contain a glass component. By forming the internal electrode 22 with only a metal component, a dense electrode can be formed, and thus the connectivity with the external electrode 12 can be further improved.

  The external electrode 12 is provided so as to cover the end surface 13 of the ceramic body 11, the ridges R13 to R16, and a part of the side surfaces 14 and 15 on the end surface 13 side. The external electrode 12 is connected to the internal electrode 22 at the end face 13 of the ceramic body 11. As the external electrode 12, one containing at least Ag and a glass component is used. The metal component constituting the external electrode 12 may further contain Pd in addition to Ag. At this time, the content of Pd contained in the external electrode 12 is 0 or more and less than 100%.

  As a glass component contained in the external electrode 12, crystallized glass is used. Since crystallized glass does not greatly reduce the viscosity of crystallized glass even when it exceeds the softening point Ts of crystallized glass during baking, crystallized glass can exist as a solid in the conductive paste forming the external electrode. . For this reason, crystallized glass can inhibit contact between metals contained in the conductive paste forming the external electrode. Therefore, by using crystallized glass as the glass component contained in the external electrode 12, it is possible to suppress the diffusion of Ag contained in the conductive paste when the external electrode 12 is formed.

  The external electrode 12 is formed by applying a conductive paste containing Ag and Pd metal powder to form a metal component contained in the external electrode 12 and glass powder contained as a glass component to the end face 13 of the ceramic body 11. It is formed by baking.

The external electrode 12 is configured so that the ratio a of the metal component and the ratio b of the crystallized glass and the void satisfy the following formulas (1) and (2) in the area ratio of the cross section at the joint portion with the internal electrode 22. ing.
86% ≦ a ≦ 97% (1)
3% ≦ b ≦ 14% (2)

  By setting the ratio a of the metal component of the external electrode 12 and the ratio b of the crystallized glass and voids within the above range in terms of the cross-sectional area ratio, Ag contained in the conductive paste forming the external electrode 12 is reduced. Since diffusion to the internal electrode 22 can be suppressed, it is possible to suppress the internal electrode 22 from growing and protruding and pushing up the external electrode 12. For this reason, while suppressing the generation | occurrence | production of the space | gap which arises in the external electrode 12, and the internal electrode 22 and the external electrode 12, while forming the precise | minute external electrode 12, the internal electrode 22 and an external electrode can be formed. The bonding strength with 12 can be increased.

  The content of Ag contained in the external electrode 12 is preferably larger than the content of Ag contained in the internal electrode 22. Since it is possible to suppress the diffusion of Ag from the internal electrode 22 to the external electrode 12 by making the content of Ag contained in the external electrode 12 larger than the content of Ag contained in the internal electrode 22, Disconnection and poor contact between the external electrode 12 and the internal electrode 22 can be suppressed.

  Moreover, as a metal component which comprises the external electrode 12, what is necessary is just to contain Ag and Pd, and a glass component, and if it is a conductive material normally used as an external electrode of a ceramic electronic component, it can be used, The external electrode 12 may contain Cu, Ni, Sn or the like as a conductive material in addition to Ag and Pd. The external electrode 12 may be composed of a plurality of metal electrode layers. For example, a Cu plating layer, a Ni plating layer, and a Sn plating layer may be formed on a base electrode containing Ag and Pd and a glass component. Also good.

  In the ceramic electronic component 10, charges are accumulated in the ceramic body 11 by applying a voltage to the pair of external electrodes 12 of the ceramic body 11.

  Thus, according to the ceramic electronic component 10 according to the present embodiment, by using crystallized glass as a glass component, the crystallized glass can exist in a solid state even during baking, so that an external electrode is formed. The diffusion of Ag contained in the conductive paste can be suppressed. In addition, by forming the external electrode so that the ratio of the metal component, the glass component and the gap is within a predetermined range, the internal electrode is prevented from pushing up the external electrode. The generation of voids between the external electrode and the external electrode can be effectively suppressed, a dense external electrode can be formed, and the bonding strength between the internal electrode and the external electrode can be increased. Parts can be provided.

  As mentioned above, although this embodiment demonstrated the case where it applied to a multilayer varistor as an example of a ceramic electronic component, the ceramic electronic component which concerns on this invention is not limited to the said embodiment. The ceramic electronic component according to the present invention can be applied to an electronic component such as a piezoelectric element (piezoelectric actuator), an inductor, a capacitor, and a thermistor as long as it is a ceramic electronic component having a ceramic body.

  The content of the present invention will be described in detail below using examples and comparative examples, but the present invention is not limited to the following examples.

<Example 1>
[Production of ceramic body]
A ZnO-based multilayer ceramic sintered body was prepared as a ceramic body (ceramic sintered body). Pd was used as a material for forming the internal electrode. A ZnO-based multilayer ceramic sintered body is mainly composed of ZnO, Co as a minor component, a rare earth metal element, a group 13 element such as B, Al, Ga and In, and an alkali metal element such as K, Rb and Cs. And alkaline earth metal elements such as Mg, Ca and Ba, simple metals such as Si, Cr and Mo, and oxides thereof.

[Preparation of conductive paste for external electrodes]
As the conductive paste, Ag is 50 to 70 parts by mass, Pd is 10 to 30 parts by mass, the glass component is 0 to 15 parts by mass, and the resin (binder) is 1 to 10 parts by mass. Part or less, a paste containing 0 parts by mass or more and 10 parts by mass or less of the dispersant, 1 part by mass or more and 40 parts by mass or less of the solvent, respectively, was mixed using a three roll mill or the like to prepare a conductive paste.

[Method of manufacturing ceramic electronic components]
A conductive paste for an external electrode is formed by screen printing on the end face portion of the ceramic body that can be connected to the internal electrode in the ceramic body, dried with hot air at 120 ° C. for 10 minutes, and then 650 ° C. in an air atmosphere. Baking was performed at 900 ° C. or less and 0 min or more and 30 min or less to produce a ceramic electronic component. Table 1 shows the metal component of the internal electrode, the metal component of the external electrode, the glass component, the ratio of the metal component, and the ratio of the glass component and the voids of the obtained ceramic electronic component.

<Examples 2 to 6>
A ceramic electronic component was produced in the same manner as in Example 1 except that the content of the metal component of the external electrode was different from the ratio of the glass component and the voids. Table 1 shows the metal component of the internal electrode, the metal component of the external electrode, the glass component, the ratio of the metal component, and the ratio of the glass component and the voids of the obtained ceramic electronic component.

<Examples 7 and 8>
A ceramic electronic component was produced in the same manner as in Example 1 except that the composition ratio of Ag and Pd of the metal component of the external electrode was changed. Table 1 shows the metal component of the internal electrode, the metal component of the external electrode, the glass component, the ratio of the metal component, and the ratio of the glass component and the voids of the obtained ceramic electronic component.

<Examples 9 to 11>
A ceramic electronic component was produced in the same manner as in Example 1 except that the composition ratio between Ag and Pd of the metal component of the internal electrode was changed. Table 1 shows the metal component of the internal electrode, the metal component of the external electrode, the glass component, the ratio of the metal component, and the ratio of the glass component and the voids of the obtained ceramic electronic component.

<Comparative Examples 1-3>
A ceramic electronic component was produced in the same manner as in Example 1 except that the glass component of the external electrode was changed from crystallized glass to softened glass. Table 2 shows the metal component of the internal electrode, the metal component of the external electrode, the glass component, the ratio of the metal component, and the ratio of the glass component and the voids of the obtained ceramic electronic component.

<Comparative Examples 4-7>
A ceramic electronic component was produced in the same manner as in Example 1 except that the type of the glass component of the external electrode was changed from crystallized glass only to softened glass and crystallized glass. Table 2 shows the metal component of the internal electrode, the metal component of the external electrode, the glass component, the ratio of the metal component, and the ratio of the glass component and the voids of the obtained ceramic electronic component.

<Comparative Examples 8 and 9>
A ceramic electronic component was produced in the same manner as in Example 1 except that the content of the metal component of the external electrode was changed. Table 2 shows the metal component of the internal electrode, the metal component of the external electrode, the glass component, the ratio of the metal component, and the ratio of the glass component and the voids of the obtained ceramic electronic component.

<Comparative Examples 10 and 11>
A ceramic electronic component was produced in the same manner as in Example 1 except that the composition ratio of Ag and Pd of the metal component of the external electrode was changed. Table 2 shows the metal component of the internal electrode, the metal component of the external electrode, the glass component, the ratio of the metal component, and the ratio of the glass component and the voids of the obtained ceramic electronic component.

<Comparative Examples 12 and 13>
A ceramic electronic component was produced in the same manner as in Example 1 except that the composition ratio between Ag and Pd of the metal component of the internal electrode was changed. Table 2 shows the metal component of the internal electrode, the metal component of the external electrode, the glass component, the ratio of the metal component, and the ratio of the glass component and the voids of the obtained ceramic electronic component.

<Evaluation method>
The ceramic electronic components of Examples 1 to 11 and Comparative Examples 1 to 13 were filled with resin, polished to the joint portion between the internal electrode and the external electrode, the protruding state of the internal electrode, the joint portion between the internal electrode and the external electrode The presence or absence of separation of the voids and the external electrodes was evaluated. Tables 3 to 7 show the evaluation results of the bondability between the internal electrode and the external electrode and the sinterability of the external electrode in each Example and Comparative Example.

  The bondability between the internal electrode and the external electrode is determined based on the protruding state of the internal electrode, the presence / absence of voids at the joint between the internal electrode and the external electrode, and the presence / absence of peeling of the external electrode. Based on the evaluation. FIG. 3 shows the evaluation criteria for the bondability between the internal electrode and the external electrode. In FIG. 3, reference numeral 11 denotes a ceramic body, reference numeral 12 denotes an external electrode, and reference numeral 22 denotes an internal electrode. As shown in FIG. 3, the judgment criteria for evaluating the bondability between the internal electrode and the external electrode are mode A to mode D. In mode A, the protruding state of the internal electrode 22, the internal electrode 22 and the external electrode 12 are There were no gaps in the joints and no peeling of the external electrodes 12. In mode B, the internal electrode 22 did not protrude and there was a gap at the joint between the internal electrode 22 and the external electrode 12, but the external electrode 12 was not peeled off. In mode C, the internal electrode 22 protrudes and there is a gap at the joint between the internal electrode 22 and the external electrode 12, but the external electrode 12 is not peeled off. In mode D, the internal electrode 22 and the external electrode 12 were peeled off. When the criteria for evaluating the bondability between the internal electrode and the external electrode do not include mode C and mode D, it is determined that the sinterability of the external electrode is good (circles in Tables 3 to 7). did.

<Evaluation>
[Examination when the glass component contained in the external electrode is only softened glass]
As shown in Table 3, when the external electrode is only softened glass, the bondability between the internal electrode and the external electrode is either mode C or mode D, and the external electrode is insufficiently sintered or overfired. It was confirmed that it was a result (see Comparative Examples 1 to 3). Therefore, when the glass component contained in the external electrode is only softened glass, a gap is formed at the joint between the internal electrode and the external electrode, or the internal electrode and the external electrode are peeled off. If it is included, it can be said that only softened glass as the glass component of the external electrode causes poor contact between the internal electrode and the external electrode.

[Examination of mixing of softened glass and crystallized glass]
As shown in Table 4, when the glass component contained in the external electrode includes only softened glass or both softened glass and crystallized glass, the bondability between the internal electrode and the external electrode is either mode C or mode D. It was confirmed that the external electrode was insufficiently sintered or oversintered (see Comparative Examples 2, 4 to 7). On the other hand, when the glass component contained in the external electrode is only crystallized glass, the bondability between the internal electrode and the external electrode is in mode A or mode B, and the sinterability of the external electrode is good. (See Example 1). Therefore, when the glass component contained in the external electrode is only crystallized glass, there is no gap between the internal electrode and the external electrode, and no peeling occurs between the internal electrode and the external electrode. It can be said that a stable connection between the internal electrode and the external electrode can be maintained.

[Examination of proportion of metal component contained in external electrode]
As shown in Table 5, the ratio of the metal component contained in the external electrode is 86.8 or more and 95.9 or less, and the ratio of crystallized glass and voids is 3.7 or more and 13.2 or less, The bondability between the internal electrode and the external electrode was in the mode A or mode B, and it was confirmed that the sinterability of the external electrode was good (see Examples 2 to 6). On the other hand, when the ratio of the metal component contained in the cross-sectional area of the external electrode and the ratio of the crystallized glass and the void are out of the above ranges, the bondability between the internal electrode and the external electrode is mode C. It was confirmed that there were many modes D and the external electrode was insufficiently sintered or oversintered (see Comparative Examples 8 and 9). Therefore, by setting the ratio of the metal component included in the cross-sectional area of the external electrode within a predetermined range, the gap between the internal electrode and the external electrode is eliminated without causing a gap at the joint between the internal electrode and the external electrode. Therefore, stable connection between the internal electrode and the external electrode can be maintained.

[Examination of mixing ratio of Pd and Ag of metal component of external electrode]
As shown in Table 6, if the mixing ratio of Pd and Ag of the external electrode is within the range of 20:80 to 50:50, the bondability between the internal electrode and the external electrode is mode A or mode B. It was confirmed that the sinterability of the external electrode was good (see Examples 4, 7, and 8). On the other hand, when the mixing ratio of Pd and Ag of the external electrode is outside the above range, when the glass component contained in the external electrode is only softened glass or softened glass and crystallized glass, the bondability between the internal electrode and the external electrode In either case, mode C or mode D was observed, and it was confirmed that the external electrode was insufficiently sintered or oversintered (see Comparative Examples 10 and 11). Therefore, by setting the mixing ratio of Pd and Ag of the metal component contained in the external electrode within a predetermined range, there is no gap at the junction between the internal electrode and the external electrode, and the internal electrode and the external electrode Since peeling does not occur in between, a stable electrode connection between the internal electrode and the external electrode can be maintained.

[Examination of mixing ratio of Pd and Ag of metal components of internal electrode]
As shown in Table 7, when the mixing ratio of Pd and Ag of the internal electrode is in the range of 100 to 0 to 50 to 50, the bondability between the internal electrode and the external electrode is mode A or mode B. It was confirmed that the sinterability of the external electrode was good (see Examples 4 and 9 to 11). On the other hand, when the mixing ratio of Pd and Ag of the internal electrode is outside the above range, when the external electrode is only softened glass or softened glass and crystallized glass, the bonding properties between the internal electrode and the external electrode are all modes. C or mode D was observed, and it was confirmed that the external electrode was insufficiently sintered or oversintered (see Comparative Examples 12 and 13). Therefore, by setting the mixing ratio of Pd and Ag of the internal electrode within a predetermined range, no separation occurs between the internal electrode and the external electrode without causing a gap in the joint portion between the internal electrode and the external electrode. Therefore, stable electrode connection can be maintained.

  As described above, the ceramic electronic component uses crystallized glass as the glass component contained in the external electrode, and the ratio of the metal component contained in the external electrode and the proportion of the glass component and the void are respectively determined in terms of the cross-sectional area ratio. By forming the external electrode so that it falls within the range, it is possible to suppress the protrusion of the internal electrode, so there is no gap between the internal electrode and the external electrode, or there is a gap between the internal electrode and the external electrode. Even if this occurs, it is possible to prevent a gap from being pushed up to the external electrode, and to increase the bonding strength between the internal electrode and the external electrode. This is considered to be because Ag contained in the conductive paste forming the external electrode could be suppressed from diffusing to the internal electrode side. Moreover, it is thought that the external electrode can form a dense electrode film by suppressing the diffusion of Ag contained in the conductive paste forming the external electrode to the internal electrode side.

  Therefore, according to the ceramic electronic component of the present invention, it is possible to effectively prevent the generation of voids between the internal electrode and the external electrode, and it is possible to increase the bonding strength between the internal electrode and the external electrode. It has been found that stable electrode connection can be maintained.

  As described above, the ceramic electronic component according to the present invention is suitable for use as an electronic component such as a laminated varistor in which an external electrode is disposed on a ceramic body including an internal electrode.

10 Ceramic electronic parts 11 Ceramic body 12 Terminal electrode (external electrode)
21 Ceramic layer 22 Internal electrode

Claims (2)

A ceramic body,
An internal electrode provided inside the ceramic body and containing Ag and Pd as metal components;
Provided on the end face of the ceramic body, including Ag and Pd as metal components, including only crystallized glass as a glass component, and having a pair of external electrodes electrically connected to the internal electrodes,
The mixing ratio of the Pd and Ag contained in the external electrodes is in the range from 20 to 80 of the 30 pairs 70, the mixing ratio of Pd and Ag contained in the internal electrode is in the range of 100: 0 50: 50 And
The external electrode includes a conductive paste including metal powder for forming a metal component contained in the external electrode and glass powder for forming a glass component contained in the external electrode on an end surface of the ceramic body. Formed by applying
A ceramic electron characterized in that the ratio a of the metal component and the ratio b of the crystallized glass and the void satisfy the following formulas (1) and (2) in the area ratio of the cross section at the joint portion with the internal electrode. parts.
86% ≦ a ≦ 97% (1)
3% ≦ b ≦ 14% (2) The ceramic electronic component according to claim 1, wherein the internal electrode does not include a glass component.