JP6992371B2 - Multilayer ceramic electronic components - Google Patents

Description

The present invention relates to laminated ceramic electronic components.

In recent years, semiconductor devices used in power modules are shifting from Si semiconductor devices to SiC semiconductor devices for the purpose of reducing power loss and miniaturization of power modules. Then, in-vehicle electronic devices (inverters, converters, etc.) using SiC are being studied. However, it is said that the operating environment temperature of the in-vehicle electronic device rises from the conventional 150 ° C. to around 250 ° C. Along with this, laminated electronic components such as capacitors mounted as in-vehicle electronic devices are also required to operate normally in an operating temperature environment of around 250 ° C.

Conventionally, Sn-based solder has been used for mounting electronic components on a wiring board. However, in mounting electronic components on a wiring substrate using a SiC semiconductor element, it has been studied to use an Ag-based conductive adhesive instead of Sn-based solder from the viewpoint of improving heat resistance.

When an electronic component using a SiC semiconductor element is mounted on a wiring board using an Ag-based conductive adhesive, if Sn is formed on the surface of the external electrode of the electronic component, the Ag-based conductive adhesive and Sn are used. Electron transfer may occur at the contact interface between the two. In particular, when the electrode is a metal lower than Ag, Sn is likely to be oxidized in a high temperature and high humidity environment. In particular, when the electronic component is a capacitor or the like, the ESR may fluctuate or the adhesive strength may decrease. Therefore, it is required that the adhesive strength and ESR are stable in a high temperature and high humidity environment.

Patent Document 1 discloses an invention relating to a laminated ceramic electronic component, and discloses an invention in which Pd plating is applied to the outer surface of an external electrode that comes into contact with an Ag-based conductive adhesive at the time of mounting.

Patent Document 2 discloses an invention relating to a laminated ceramic electronic component, wherein an external electrode that comes into contact with an Ag-based conductive adhesive at the time of mounting is composed of a Cu base electrode layer and an Ag-Pd outermost electrode layer. An invention having a two-layer structure is disclosed.

However, in Patent Document 1, it is essential to perform Pd plating. Pd plating causes great damage to the element body and may adversely affect electrical reliability, mechanical strength and the like. In Patent Document 2, in order to form a two-layer structure, it is necessary to perform the application step of the paste for the external electrode twice, and further, it is necessary to strictly control the film thickness of the base electrode layer. That is, the manufacturing cost is significantly increased as compared with the conventional laminated ceramic electronic components.

JP-A-2015-29050 Japanese Unexamined Patent Publication No. 2002-158137

The present invention has been made in view of the above-mentioned actual conditions, and the fluctuation of ESR under high temperature and high humidity is small, and the deterioration of adhesive strength is small when an Ag-based conductive adhesive is used. The purpose is to obtain parts.

In order to achieve the above object, the laminated ceramic electronic component of the present invention is used.
A laminated ceramic electronic component having an element body in which a plurality of internal electrode layers and dielectric layers are alternately laminated, and an external electrode electrically conductive with the internal electrode layer.
The internal electrode layer contains Ni as a main component and contains Ni.
The external electrode contains one or more conductive components selected from the group consisting of Ag, Pd and Ni.
It is characterized in that NiO is present on the outer surface of the external electrode.

By having the above-mentioned characteristics, the laminated ceramic electronic component of the present invention reduces the fluctuation of ESR under high temperature and high humidity, and further reduces the deterioration of the adhesive strength when the Ag-based conductive adhesive is used. Can be done.

The external electrode may contain at least Ag and Ni as the conductive component.

The area ratio of NiO to the entire outer surface of the external electrode may be 3% or more and 70% or less.

The contents of Ag, Pd and Ni with respect to the whole conductive component are Ag: 10% by mass or more and 95% by mass or less, Pd: 0.0% by mass or more and 50% by mass or less, Ni: 5.0% by mass or more and 60% by mass. It may be less than or equal to%.

The content ratio of Pd to Ag may be 3.0% or more on a mass basis.

FIG. 1 is a schematic cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention. FIG. 2 is an enlarged schematic view of an external electrode of the multilayer ceramic capacitor shown in FIG. 1.

Hereinafter, the present invention will be described based on the embodiments shown in the drawings.

Multilayer Ceramic Capacitor As an embodiment of the monolithic ceramic electronic component according to this embodiment, the monolithic ceramic capacitor shown in FIG. 1 will be described.

As shown in FIG. 1, the laminated ceramic capacitor 1 as an example of a laminated ceramic electronic component has a capacitor element main body 10 having a structure in which a dielectric layer 2 and an internal electrode layer 3 are alternately laminated. The internal electrode layers 3 are laminated so that their end faces are alternately exposed on the surfaces of the two opposing ends of the capacitor element main body 10. The pair of external electrodes 4 are formed at both ends of the capacitor element main body 10 and are connected to the exposed end faces of the alternately arranged internal electrode layers 3 to form a capacitor circuit.

The size of the monolithic ceramic capacitor 1 is not particularly limited. For example, the length in the X-axis direction is 0.6 mm to 5.7 mm, the length in the Y-axis direction is 0.3 mm to 5.0 mm, and the length in the Z-axis direction is 0.3 mm to 5.0 mm.

The material of the dielectric layer 2 is not particularly limited, and is composed mainly of, for example, a dielectric material having a perovskite structure such as ABO ₃ or an alkaline niobate ceramic.

In ABO ₃ , A is at least one kind such as Ca, Ba, Sr, and B is at least one kind such as Ti, Zr.

In addition, examples of subcomponents include, but are not limited to, alkali metal compounds such as silicon dioxide, aluminum oxide, and magnesium oxide, manganese oxide, rare earth element oxides, and vanadium oxide. The content may be appropriately determined according to the composition and the like.

The number of layers of the dielectric layer may be appropriately determined according to the intended use and the like.

The internal electrode layer 3 contains Ni as a main component. The term "containing Ni" as the main component means that the content ratio of Ni to the entire conductive material contained in the internal electrode layer 3 is 70% by mass or more. Further, the type of the conductive material contained other than Ni is not particularly limited. For example, metals such as Cu and Pd, or alloys of them with Ni can be used. The internal electrode layer 4 may contain various trace components such as P in an amount of about 0.1% by mass or less.

The internal electrode layer 3 may be formed by using a commercially available electrode paste, and the thickness of the internal electrode layer 3 may be appropriately determined according to the intended use and the like.

The external electrode 4 contains one or more conductive components selected from the group consisting of Ag, Pd and Ni. Further, it may contain a glass component. The type and content of the glass component are not particularly limited, and for example, the weight ratio of the conductive component: the glass component may be 97: 3 to 80:20.

Further, the external electrode 4 preferably contains at least Ag and Ni as conductive components, and more preferably contains all of Ag, Ni and Pd. It is preferable to contain Ag in order to improve the adhesive strength by containing a conductive component (Ag) common to the Ag-based conductive adhesive. It is preferable to contain Ni in order to facilitate the presence of NiO4a on the outer surface of the external electrode 4 as described later.

Further, by containing Pd, it becomes easy to suppress the migration of Ag. Pt or Au may be used instead of Pd, and even if Pt or Au is used, the same migration suppressing effect as Pd can be obtained. However, the cost is significantly higher when Pt or Au is used.

The contents of Ag, Pd and Ni with respect to the total contained conductive component are Ag: 10% by mass or more and 95% by mass or less, Pd: 0.0% by mass or more and 50% by mass or less, Ni: 5.0% by mass or more and 60. It is preferably mass% or less. The contents of Ag, Pd, and Ni with respect to the entire conductive component are values rounded to the first decimal place or the second decimal place.

By setting the Ni content within the above range, it becomes easy to satisfactorily control the area ratio of NiO4a to the entire outer surface of the external electrode 4 described later. Further, by setting the Ni content to 60% by mass or less, it becomes easy to suppress deterioration of the adhesive strength with the Ag-based conductive adhesive under high temperature and high humidity. Further, from the viewpoint of facilitating better control of the area ratio of NiO4a, it is more preferable that the Ni content ratio is 50% by mass or less.

By setting the Ni content to 5.0% by mass or more, it becomes easy to suppress the amount of Pd used, and it is possible to facilitate cost reduction. Further, it is more preferable that the Ni content is 10% by mass or more. When the content is 10% by mass or more, the capacitance of the monolithic ceramic capacitor 1 becomes good.

Further, the content ratio of Pd to Ag in the external electrode 4 is preferably 3.0% or more, more preferably 3.1% or more, and further preferably 5.3% or more in terms of weight ratio. .. By increasing the content ratio of Pd to Ag, migration of Ag can be suppressed more satisfactorily. There is no particular upper limit to the content ratio of Pd to Ag, and increasing the content ratio of Pd makes it easier to improve the capacitance of the multilayer ceramic capacitor 1, but the cost increases. In order to suppress the increase in cost while sufficiently increasing the migration suppressing effect of Ag, for example, the content ratio of Pd to Ag may be 100% or less, or 20% or less.

As shown in FIG. 2, the external electrode 4 according to the present embodiment has NiO4a on the outer surface. The presence of NiO4a makes it possible to obtain a monolithic ceramic capacitor 1 in which deterioration of the adhesive strength with the Ag-based conductive adhesive and fluctuation of ESR are remarkably suppressed under high temperature and high humidity.

The area ratio of NiO4a to the entire outer surface of the external electrode 4 is not particularly limited, but is preferably 3% or more and 70% or less. When it is 3% or more, the effect of suppressing the deterioration of the adhesive strength and the fluctuation of ESR under high temperature and high humidity becomes large. By setting it to 70% or less, the ESR itself can be reduced. Further, the effect of suppressing the deterioration of the adhesive strength and the fluctuation of ESR under high temperature and high humidity is increased.

The thickness of NiO4a is not particularly limited, but may be about 1 μm on average.

The method for measuring the area ratio of NiO4a is not particularly limited, and can be measured using, for example, EPMA. Further, it is more preferable that the area ratio of NiO4a to the entire outer surface of the external electrode 4 is 5% or more. When it is 5% or more, the effect of suppressing the deterioration of the adhesive strength under high temperature and high humidity becomes larger. Further, it is more preferable that the area ratio of NiO4a to the entire outer surface of the external electrode 4 is 55% or less. When it is 55% or less, the effect of suppressing the fluctuation of ESR under high temperature and high humidity is further enhanced.

In the present embodiment, the side surfaces of the element main body 10 in the Y-axis direction and the Z-axis direction are exposed except for the portion covered by the external electrode 4. However, various insulating layers may be present on the side surface of the element main body 10 as needed.

Method for Manufacturing a Multilayer Ceramic Capacitor Next, a method for manufacturing a monolithic ceramic capacitor 1 as an embodiment of the present invention will be specifically described.

First, a paste for a green sheet is prepared in order to produce a green sheet that will form the dielectric layer 2 shown in FIG. 1 after firing.

The green sheet paste is usually composed of an organic solvent-based paste obtained by kneading a ceramic powder and an organic vehicle, or a water-based paste.

As the raw material of the ceramic powder, various compounds to be composite oxides and oxides, for example, carbonates, nitrates, hydroxides, organic metal compounds and the like can be appropriately selected and mixed and used.

An organic vehicle is a binder dissolved in an organic solvent. The binder used for the organic vehicle is not particularly limited, and may be appropriately selected from various ordinary binders such as ethyl cellulose and polyvinyl butyral. The organic solvent used is not particularly limited, and may be appropriately selected from various organic solvents such as alcohol, acetone, and toluene.

Further, the green sheet paste may contain additives selected from various dispersants, plasticizers, dielectrics, subcomponent compounds, glass frits, insulators and the like, if necessary.

Examples of the plasticizer include phthalates such as dioctyl phthalate and benzyl butyl phthalate, adipic acid, phosphoric acid esters, glycols and the like.

Next, a paste for the internal electrode layer is prepared in order to manufacture the internal electrode pattern layer that will form the internal electrode layer 3 shown in FIG. 1 after firing. The paste for the internal electrode layer is prepared by kneading a conductive material made of at least various conductive metals and alloys containing Ni and the above-mentioned organic vehicle.

The paste for an external electrode, which constitutes the external electrode 4 shown in FIG. 1 after firing, is produced by dispersing at least one of Ag, Pd, and Ni, a conductive material, and glass frit in a vehicle.

Using the paste for the green sheet and the paste for the internal electrode layer prepared above, the green sheet and the internal electrode pattern layer are alternately laminated and pressed in the stacking direction to obtain a green laminate.

The method for forming the internal electrode pattern layer is not particularly limited, and may be formed by a thin film forming method such as thin film deposition or sputtering, in addition to a printing method and a transfer method.

Green chips are obtained by cutting the green laminate to an appropriate size as needed. The plasticizer is removed from the green chips by solidification and drying, and the green chips are solidified. The green chips after solidification and drying are put into a barrel container together with the media and the polishing liquid, and are barrel-polished by a horizontal centrifugal barrel machine or the like. After barrel polishing, the green chips are washed with water and dried. The element main body 10 is obtained by performing a binder removal step, a firing step, and an annealing step, if necessary, on the dried green chip.

The binder removal step may be performed under known conditions, for example, the holding temperature may be 200 ° C. to 400 ° C. The firing step is carried out in a reducing atmosphere, and the annealing step is carried out in a neutral or weakly oxidizing atmosphere. Other firing conditions or annealing conditions may be known conditions, for example, the holding temperature for firing is 1000 ° C to 1300 ° C, and the holding temperature for annealing is 500 ° C to 1100 ° C.

The binder removal step, firing step, and annealing step may be performed continuously or independently.

The element main body 3 obtained as described above may be subjected to processing such as polishing, if necessary.

Next, the paste for the external electrode is applied to both end faces of the element main body 10 in the X-axis direction, dried, and then baked at 700 to 900 ° C. for 1 to 20 minutes.

The method for producing the paste for the external electrode is the same as the method for producing the paste for the internal electrode layer. Further, the raw material of the paste for the external electrode may be a single metal powder of each conductive component, or may be an alloy powder such as Ag-Pd powder. Further, the paste for an external electrode may contain a glass component, and as a raw material for the glass component, for example, a glass _- forming oxide such as _{B2O3 or SiO 2 and} various alkaline earth oxides such as BaO, CaO, SrO, etc. , And / or those to which various metal oxides such as ZnO, Al ₂ O ₃ , and MnO are added can be used.

Here, the atmosphere at the time of baking is an inert atmosphere such as a nitrogen atmosphere. When baking is performed in an active atmosphere containing oxygen, the internal electrode layer is oxidized and the performance as a capacitor cannot be obtained.

Next, the oxidation treatment is performed in an active atmosphere containing oxygen, such as in the atmosphere. The oxidation treatment is carried out at 250 to 400 ° C. for 0.01 to 3 hours. By performing the oxidation treatment, only Ni existing on the outer surface of the baked external electrode is oxidized to form NiO. Then, the monolithic ceramic capacitor 1 according to the present embodiment is obtained.

The method for attaching the multilayer ceramic capacitor 1 according to the present embodiment to the substrate using an Ag-based conductive adhesive is not particularly limited. When a polyimide substrate is used, it can be adhered by heating at 200 to 250 ° C. for 15 to 60 minutes, for example.

In the present embodiment, it is preferable that the order is such that the external electrode is oxidized and then the laminated ceramic capacitor is adhered to the substrate. If the laminated ceramic capacitor is adhered to the substrate and then the oxidation treatment is performed, the external electrode may expand when Ni on the outer surface of the external electrode is oxidized to NiO, and the adhesive strength may be significantly reduced. Because.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be variously modified without departing from the gist of the present invention.

For example, although the external electrode has a single-layer structure in the above embodiment, it may have a multi-layer structure. However, in the case of a multi-layer structure, it is necessary to perform the application step of the paste for the external electrode twice or more. Further, it is necessary to strictly control the film thickness of the layer other than the outermost layer, that is, the underlying layer. Therefore, in the case of a multi-layer structure, the manufacturing cost increases. The multilayer ceramic capacitor of the present embodiment can reduce the fluctuation of ESR under high temperature and high humidity even if the external electrode has a single layer structure, and can reduce the deterioration of the adhesive strength. That is, the cost can be reduced as compared with the case where the external electrode has a multilayer structure.

Further, the laminated electronic component of the present invention is not limited to the laminated ceramic capacitor, and can be applied to other laminated electronic components. Other laminated electronic components include all electronic components in which a dielectric layer is laminated via internal electrodes, such as bandpass filters, laminated three-terminal filters, piezoelectric elements, chip thermistors, chip varistor, and other surface mounters. (SMD) Chip type electronic components and the like are exemplified.

Hereinafter, the present invention will be described based on more detailed examples, but the present invention is not limited to these examples.

(Experimental Example 1)
As described below, the multilayer ceramic capacitor samples of Examples 1 to 18 (hereinafter, also simply referred to as capacitor samples) were prepared.

First, BaTIO ₃ ceramic powder: 100 parts by weight, polyvinyl butyral resin: 10 parts by weight, dioctyl phthalate (DOP) as a plasticizer: 5 parts by weight, and alcohol as a solvent: 100 parts by weight are mixed by a ball mill. And made into a paste to obtain a paste for a green sheet.

Separately from the above, 44.6 parts by weight of Ni particles, 52 parts by weight of terpineol, 3 parts by weight of ethyl cellulose and 0.4 parts by weight of benzotriazole were mixed for 1 hour with a rake. After that, the conductor paste for the internal electrode layer was prepared by kneading with three rolls and forming a slurry.

A green sheet was formed on the PET film using the green sheet paste prepared above. Next, the internal electrode pattern layer was printed in a predetermined pattern using the conductor paste for the internal electrode layer on this, and a green sheet having the internal electrode pattern layer was obtained.

After laminating green sheets having an internal electrode pattern layer to produce an internal laminate, an appropriate number of green sheets are formed above and below the internal laminate using a green sheet paste, and the green sheets are added in the stacking direction. The green laminate was obtained by pressure bonding.

Next, the green laminate is appropriately cut to obtain a capacitor sample having a 3216 shape (X-axis direction: 3.2 mm, Y-axis direction: 1.6 mm, Z-axis direction: 1.6 mm). Got

Next, the obtained green chip was subjected to binder removal treatment, firing and annealing under the following conditions to obtain an element main body.

The binder removal treatment conditions were a temperature rising rate of 60 ° C./hour, a holding temperature of 260 ° C., a temperature holding time of 8 hours, and an atmosphere of air.

The firing conditions were a heating rate of 800 ° C./hour, a holding temperature of 1000 ° C. to 1200 ° C., and a temperature holding time of 0.1 hour. The cooling rate was 800 ° C./hour. The atmosphere gas was a humidified N ₂ + H ₂ mixed gas.

The annealing conditions were a temperature rise rate: 200 ° C./hour, a holding temperature: 500 ° C. to 1000 ° C., a temperature holding time: 2 hours, a cooling rate: 200 ° C./hour, and an atmosphere gas: humidified _N2 gas.

A wetter was used for humidifying the atmospheric gas during firing and annealing.

Then, the surface of the obtained element body was appropriately polished.

Next, the conductive material, the glass frit, and the vehicle constituting the conductor paste for the external electrode were prepared.

As the conductive material, Ag powder, Pd powder and Ni powder were prepared, and finally weighed so that the internal components of the external electrode had the weight ratio shown in Table 1. The average particle size of the conductive material was 0.3 μm.

The glass frit was prepared by the method shown below. First, strontium carbonate, boron oxide, silicon oxide, aluminum hydroxide, and manganese carbonate, which are raw materials for glass, were prepared. Next, when vitrified, the glass composition is SrO: 45.0 wt%, B ₂ O ₃ : 20.0 wt%, Al ₂ O ₃ : 15.0 wt%, SiO ₂ : 10.0 wt% in terms of oxide. , MnO: 10.0 wt% was weighed. Then, each glass raw material was mixed with a rake for 1 hour to obtain a mixed powder. Next, the mixed powder is put into a platinum crucible, the temperature is raised to 1500 ° C. at a speed of 300 ° C./h in an ultra-elevating temperature type electric furnace, the temperature is maintained at that temperature for 1 hour, and then the mixed powder liquid is dropped into water. And got the glass. This glass was pulverized by pulverizing it with a ball mill for 48 hours to obtain a glass frit. The particle size distribution was measured by a laser diffraction method using SALD1000 manufactured by Shimadzu Corporation. At this time, the average particle size was 3 μm.

As the vehicle, a mixture of terpineol and an acrylic resin at a weight ratio of 70:30 was used.

Next, a predetermined amount of the conductive material, the glass frit, and the vehicle were mixed, mixed with a raker for 1 hour, and then kneaded with three rolls to form a slurry to prepare a conductor paste for an external electrode. At this time, the content of the vehicle was set to 30 parts by weight with respect to 100 parts by weight of the conductor paste for the external electrode. Further, the content of the glass frit with respect to 100 parts by weight of the conductive material was set to 5 parts by weight.

The obtained conductor paste for an external electrode was applied to the element body and dried. Next, baking was performed at 750 ° C. in a nitrogen atmosphere. Further, in the atmospheric atmosphere, the mixture was heated at 260 ° C. for 1 hour to oxidize the outer surface of the external electrode to form NiO on the outer surface.

Next, in order to perform various measurements, a capacitor sample was adhered on the polyimide substrate. Specifically, an Ag-based conductive adhesive containing an epoxy-based resin was used and heated at 200 ° C. for 30 minutes for adhesion.

Then, the capacitance, ESR, adhesive strength, migration, and the area ratio of NiO to the entire outer surface of the external electrode (hereinafter, also simply referred to as NiO ratio) were measured. Hereinafter, the measurement method and evaluation criteria for each characteristic value will be described.

Capacitance and ESR were measured using an LCR meter. Regarding the capacitance, the case where the measured value with respect to the design value was 95% or more was good, and the case where it was 100% or more was further good. In Table 1, the case of 100% or more is marked with ⊚, the case of 95% or more and less than 100% is marked with ◯, and the case of less than 95% is marked with ×. The design value of the capacitance is εSn / d (ε: dielectric constant of the dielectric layer, S: area of the overlapping portion of the internal electrode layers, n: number of dielectric layers, d: thickness of the dielectric layer). It is calculated. When determining the design value of the capacitance, the dielectric constant ε of the dielectric layer was assumed to be 1000.

The ESR was measured before and after the high temperature and high humidity test, and the ESR measured before the high temperature and high humidity test was defined as the initial ESR, and the rate of change after the high temperature and high humidity test before the high temperature and high humidity test was defined as the ESR volatility. In this example, the case where the ESR volatility was 5% or less was regarded as good, and the case where it was 0% was particularly good. The high temperature and high humidity test was performed by leaving the capacitor sample in an environment with a temperature of 85 ° C. and a humidity of 85% for 1000 hours. The initial ESR is not particularly limited, but is preferably less than 60 mΩ.

The adhesive strength was measured before and after the cycle test, and the rate of decrease in the adhesive strength measured after the cycle test with respect to the adhesive strength measured before the cycle test was defined as the adhesive strength deterioration rate. The adhesive strength was measured by performing a fixing strength test. Specifically, the fixing strength is determined by a method in which the center of the side surface of a capacitor bonded to a polyimide substrate with an Ag conductive adhesive is pressed with a pressure rod at a speed of 10 mm / min, and the broken strength is used as the bonding strength. It was measured. In the cycle test, the temperature of the capacitor sample was raised from −55 ° C. to 200 ° C. and returned to −55 ° C. for 3000 cycles. In this example, the case where the adhesive strength deterioration rate is 20% or less is good, and the case where it is 5% or less is particularly good.

The migration was evaluated by dropping pure water on the capacitor sample, applying a voltage of 100 V / mm, and measuring the time until a short circuit occurred. The case where the time until the short circuit exceeds 30 seconds is good, the case where it exceeds 60 seconds is further good, and the case where it exceeds 90 seconds is the best. In Table 1, the case of more than 90 seconds is marked with ⊚, the case of more than 60 seconds and 90 seconds or less is marked with ◯, the case of more than 30 seconds and 60 seconds or less is marked with Δ, and the case of more than 30 seconds is marked with ×.

Regarding the NiO ratio, the outer surface of the external electrode was observed by EPMA after polishing the capacitor sample. The ratio of NiO to the total of NiO, Ni, Ag and Pd on the outer surface of the external electrode was measured and used as the NiO ratio.

The weight ratios of the external electrode components in Table 1 are described by measuring the weight ratios of Ag, Pd, Ni and NiO in the entire external electrode by EPMA. The weight ratio of the components inside the external electrode is described by measuring the weight ratio of Ag, Pd, and Ni inside the electrode in which NiO does not exist among the external electrodes by EPMA. It was confirmed that the weight ratio of the internal component of the external electrode was substantially the same as the weight ratio of Ag powder, Pd powder and Ni powder as the conductive material at the time of weighing.

In Example 19, unlike Examples 1 to 18, Ag—Pd alloy powder having Ag: Pd = 90:10 (weight ratio) was prepared at the time of producing the conductor paste for the external electrode. Then, weighed so that Ag—Pd alloy powder: Ni powder = 70:30 (weight ratio). Other points were the same as those in Examples 1 to 18.

In Comparative Example 1, unlike Examples 1 to 18, the outer surface of the external electrode was not oxidized. Instead, the external electrodes were plated. Specifically, a Ni plating film was formed on the external electrode, and a Sn plating film was further formed on the Ni plating film. Other points were the same as those in Examples 1 to 18. In Comparative Example 1, the Ni plating film and the Sn plating film are thinner than the external electrodes. Therefore, in the comparison between the external electrode constituents and the external electrode internal components, the Ni and Sn contents in each plating film are negligibly small.

From Table 1, all the characteristics of Examples 1 to 19 in which NiO was present on the outer surface of the external electrode were good. On the other hand, in Comparative Example 1 in which NiO was not present on the outer surface of the external electrode, the ESR volatility and the adhesive strength deterioration rate were significantly inferior. That is, the adhesive strength and ESR became unstable under high temperature and high humidity.

Each of the examples having a NiO ratio of 3% or more and 70% or less had excellent initial ESR, ESR volatility, and adhesive strength deterioration rate as compared with each example having a NiO ratio of more than 70%. Further, in each example in which the NiO rate was 50% or less, the ESR volatility was particularly excellent.

The example in which the Pd / Ag in the external electrode was 5.3% or more had good migration as compared with the other examples.

Each embodiment in which the weight ratio of NiO in the entire external electrode is 0.01% by mass or more or Pd / Ag = 100% is 0.005% by mass and Pd / Ag = 3.1% by mass or 5.3. The capacitance was superior to that of the examples in which the mass was%.

(Experimental Example 2)
A capacitor sample was prepared under the same conditions as in Example 8 except that the oxidation treatment conditions on the outer surface of the external electrode were changed. The results are shown in Table 2.

From Table 2, the NiO ratio can be changed by controlling the oxidation treatment conditions, and good characteristics are shown when NiO is present on the outer surface of the external electrode.

1 ... Multilayer ceramic capacitor 2 ... Dielectric layer 3 ... Internal electrode layer 4 ... External electrode 4a ... NiO
10 ... Element body

Claims (2)

A laminated ceramic electronic component having an element body in which a plurality of internal electrode layers and dielectric layers are alternately laminated, and an external electrode electrically conductive with the internal electrode layer.
The internal electrode layer contains Ni as a main component and contains Ni.
The external electrode contains Ag, Pd and Ni as conductive components and contains Ag, Pd and Ni as conductive components.
The contents of Ag, Pd and Ni with respect to the entire conductive component are Ag: 10% by mass or more and 95% by mass or less, Pd: 0.0% by mass or more and 50% by mass or less, Ni: 10% by mass or more and 60% by mass or less. The content ratio of Pd to Ag is 3.0% or more on a mass basis.
A laminated ceramic electronic component characterized in that NiO is present on the outer surface of the external electrode. The laminated ceramic electronic component according to claim 1 , wherein the area ratio of NiO to the entire outer surface of the external electrode is 3% or more and 70% or less.

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