JPWO2006025201A1 - Conductive nickel paste - Google Patents

Abstract

In the conductive nickel paste containing the ceramic powder so that the sintering suppression effect can be exhibited, the sintering suppression effect can be more reliably exhibited. In the conductive nickel paste containing nickel powder, ceramic powder, and organic vehicle, a ceramic powder having nickel and / or a nickel compound and a rare earth element compound on the surface and / or surface layer thereof is used. When this conductive nickel paste is used to form the internal electrodes (3, 4), the ceramic powder contained in the conductive nickel paste has good compatibility (wetability) with nickel, and the ceramic layer (2) Sufficient sintering suppression effect is maintained without discharging ceramic powder from the internal electrodes (3, 4) up to the sintering temperature range.

Description

  The present invention relates to a conductive nickel paste, and more particularly to a conductive nickel paste used for forming internal electrodes of a multilayer ceramic electronic component.

  A multilayer ceramic electronic component such as a multilayer ceramic capacitor includes a component body having a structure in which a plurality of ceramic layers are stacked. Inside the component main body, an internal conductor is formed along a specific interface between ceramic layers, for example, for forming capacitance, inductance, etc., or for electrical wiring.

  In order to obtain the above-described component main body, a plurality of ceramic green sheets are prepared, a conductive paste film serving as an internal conductor is formed on a specific ceramic green sheet by printing, and then the plurality of ceramic green sheets are stacked and pressed. Thus, a raw laminate is obtained, and the raw laminate is fired. The conductive paste used to form the conductive paste film serving as the above-described inner conductor is produced by dispersing, for example, powder of nickel, copper, silver-palladium alloy or the like as a conductive component in an organic vehicle. .

  To reduce the size and performance of multilayer ceramic electronic components, especially for multilayer ceramic capacitors, it is necessary to reduce the thickness of internal electrodes as much as possible and increase the number of layers per unit volume. It is. In order to make it possible to reduce the thickness of the internal electrode, it is effective to reduce the physical size of the conductive metal powder particles used in the conductive paste as much as possible.

  However, when the particle size is reduced, the sintering start temperature is lowered, and therefore the coverage (coverage) of the internal electrode is reduced, or due to the difference in shrinkage behavior due to sintering between the internal electrode and the ceramic. As a result, delamination may occur. Therefore, a technique for suppressing the sintering of the conductive metal powder contained in the conductive paste is desired.

  As a sintering suppression technique as described above, there is a technique of adding a ceramic component to a conductive paste (see, for example, Patent Documents 1 and 2).

  Patent Document 1 describes a conductive paste containing metal particles such as nickel particles and dielectric ceramic particles. In a specific embodiment, it is described that the dielectric ceramic particles are adsorbed on the surface of the metal particles.

  On the other hand, Patent Document 2 discloses a conductive paste containing a nickel composite conductor in which nickel and titanate are integrated in a granular form. In a specific embodiment, it is described that the titanate is deposited and integrated on the surface of nickel particles, or that nickel and titanate are mixed and integrated. In addition, it is disclosed that plasma spraying is applied to integrate nickel and titanate.

  However, when the conductive paste film for the internal electrode is formed using the conductive paste described in Patent Document 1, in the step of firing the raw laminate, metal particles such as nickel particles in the conductive paste When the sintering starts, the dielectric ceramic particles are easily discharged from the internal electrode or the conductive paste film to the ceramic layer side. As a result, in the sintering temperature range of the ceramic layer, the dielectric ceramic particles are Sintering suppression effect may be lost.

  On the other hand, even when the conductive paste film for the internal electrode is formed using the conductive paste described in Patent Document 2, the sintering suppression effect is lost or the sufficient sintering suppression effect is not obtained. There are things to do. That is, when titanate is deposited on the surface of nickel particles, the same phenomenon as in Patent Document 1 occurs, and the sintering suppression effect may be lost. When nickel and titanate are mixed, nickel particles still tend to stick together, and a sufficient sintering suppression effect may not be obtained. In addition, when plasma spraying is applied because of the integration of nickel and titanate, the reaction time of plasma spraying is instantaneous, and the reaction between nickel and titanate is not sufficient, so nickel is reduced. In this case, nickel and titanate easily peel off, and this also causes the same problem as in Patent Document 1.

For this reason, when the internal electrode is thinned, the sintering of the conductive paste film that becomes the internal electrode proceeds too much during the firing of the raw laminate for the multilayer ceramic electronic component. Problems such as reduced electrode coverage and delamination have not been completely solved.
JP-A-57-30308 JP 2000-233202 A

  Therefore, an object of the present invention is to provide a conductive nickel paste that can make problems such as reduction in coverage and delamination more difficult to occur.

  The present invention is directed to a conductive nickel paste containing nickel powder, ceramic powder, and an organic vehicle. In order to solve the above technical problems, the ceramic powder is applied to the surface and / or surface layer of the ceramic powder. It is characterized by using a material in which nickel and / or a nickel compound is present.

  In the present invention, the ceramic powder may have nickel and / or a nickel compound attached to its surface, or may have a nickel compound diffused into its surface layer. In the former case, when a nickel compound is attached, the nickel compound is preferably nickel hydroxide, nickel oxide, or both. In the latter case, the nickel compound is preferably nickel oxide.

  In the conductive nickel paste according to the present invention, the amount of nickel and / or nickel compound is preferably 5 to 100 parts by mole with respect to 100 parts by mole of the ceramic powder.

  The conductive nickel paste according to the present invention preferably contains not only nickel and / or a nickel compound but also a rare earth element compound on the surface and / or surface layer of the ceramic powder.

  In the preferred embodiment described above, the amount of nickel and / or nickel compound is preferably 1 to 100 parts by mole with respect to 100 parts by mole of the ceramic powder. On the other hand, the amount of the rare earth element compound is preferably 0.01 to 10 mole parts relative to 100 mole parts of the ceramic powder.

  In the conductive nickel paste according to the present invention, the particle size of the ceramic powder is preferably 50 nm or less.

  According to the present invention, the ceramic powder can have good conformability (wetability) to nickel by the action of nickel and / or nickel compounds present on the surface and / or surface layer. Therefore, it is possible to make the ceramic powder difficult to be discharged from the conductive nickel paste film serving as the internal electrode during firing. As a result, the ceramic powder can sufficiently remain in the internal electrode, for example, up to a temperature of 900 ° C. or higher, which is the sintering temperature range of the dielectric ceramic. The effect which suppresses a tie can be exhibited. For this reason, even if the internal electrode is thinned, the continuity of the conductor film constituting the internal electrode is increased, and the coverage can be improved. Further, delamination can be made difficult to occur.

  The effects as described above are more remarkably exhibited when a rare earth element compound is further present on the surface and / or surface layer of the ceramic powder. This is presumably because the rare earth element compound has an action to keep nickel and / or the nickel compound on the surface and / or surface layer of the ceramic powder.

  In the conductive nickel paste according to the present invention, the amount of nickel and / or nickel compound present on the surface and / or surface layer of the ceramic powder is 5 to 100 mol parts with respect to 100 mol parts of the ceramic powder. If the rare earth element compound is present on the surface and / or surface layer of the ceramic powder, the amount of nickel and / or nickel compound is 1 with respect to 100 mole parts of the ceramic powder. When it is selected so as to be ˜100 mol parts, the effects as described above can be achieved more reliably.

  When the rare earth element compound is present on the surface and / or surface layer of the ceramic powder, the amount of the rare earth element compound is selected to be 0.01 to 10 mol parts with respect to 100 mol parts of the ceramic powder. The effects as described above can be achieved more reliably, and the characteristics of the ceramic electronic component configured using the conductive nickel paste can be reliably prevented from deteriorating.

  In the conductive nickel paste according to the present invention, when the particle size of the ceramic powder is 50 nm or less, it is possible to prevent the ceramic powder from becoming an obstacle to reducing the thickness of the internal electrode and improving the coverage.

FIG. 1 is a cross-sectional view schematically showing a multilayer ceramic capacitor 1 as an example of a multilayer ceramic electronic component constructed using the conductive nickel paste according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Multilayer ceramic capacitor 2 Ceramic layer 3, 4 Internal electrode 5 Component main body 6, 7 External electrode

  FIG. 1 is a cross-sectional view schematically showing a multilayer ceramic capacitor 1 as an example of a multilayer ceramic electronic component constructed using the conductive nickel paste according to the present invention.

  The multilayer ceramic capacitor 1 includes a component body 5 having a multilayer structure including a plurality of ceramic layers 2 made of dielectric ceramics and internal electrodes 3 and 4 formed along a specific interface between the ceramic layers 2. I have. External electrodes 6 and 7 are formed at each end of the component body 5, respectively. The external electrodes 6 and 7 are electrically connected to the internal electrodes 3 and 4, respectively, and the internal electrode 3 electrically connected to one external electrode 6 and the internal electrode electrically connected to the other external electrode 7, respectively. The electrodes 4 are alternately arranged in the stacking direction.

  In order to manufacture such a multilayer ceramic capacitor 1, the following steps are performed.

  First, a ceramic green sheet to be the ceramic layer 2 is prepared, and a conductive nickel paste for forming the internal electrodes 3 and 4 is prepared.

  Next, a conductive nickel paste is applied on the ceramic green sheet by printing, whereby a conductive nickel paste film to be the internal electrodes 3 and 4 is formed.

  Next, a plurality of ceramic green sheets are laminated and pressure-bonded, and a cutting process is performed as necessary, so that a raw laminated body to be the component main body 5 is obtained.

  Next, the raw laminate is fired, whereby a sintered component body 5 is obtained. If the external electrodes 6 and 7 are formed at both ends of the component body 5, the multilayer ceramic capacitor 1 is completed.

  As described above, the conductive nickel paste used to form the conductive nickel paste film to be the internal electrodes 3 and 4 has nickel powder and nickel and / or a nickel compound on the surface and / or surface layer thereof. Contains the ceramic powder present and the organic vehicle.

  When such a conductive nickel paste is used, the nickel powder and / or nickel compound present on the surface and / or surface layer of the ceramic powder improves the familiarity (wetability) with nickel, and the firing process described above. In this case, the ceramic powder can be hardly discharged from the internal electrodes 3 and 4. Therefore, the ceramic powder remains in the internal electrodes 3 and 4 up to, for example, 900 ° C. or higher, which is the sintering temperature range of the ceramic layer 2, and the sintering of the internal electrodes 3 and 4 is suppressed to such a high temperature range. The effect can be sustained. As a result, even if the internal electrodes 3 and 4 are thinned, the continuity of the conductor film constituting the internal electrodes 3 and 4 is increased, and the coverage can be improved.

  The ceramic powder contained in the above-described conductive nickel paste may have nickel and / or a nickel compound attached to the surface thereof, or may have a nickel compound diffused in the surface layer thereof. When the nickel compound is attached to the surface of the ceramic powder as in the former, the nickel compound is preferably nickel hydroxide and / or nickel oxide. Further, as in the latter case, when the nickel compound is diffused in the surface layer of the ceramic powder, the nickel compound is preferably nickel oxide.

  Moreover, in the conductive nickel paste used, when the amount of nickel and / or nickel compound is 5 to 100 parts by mole with respect to 100 parts by mole of the ceramic powder, the above-described effects can be more reliably exhibited. Can do.

  The ceramic powder in which nickel and / or nickel compounds are present on the surface and / or surface layer as described above can be obtained, for example, as follows.

  That is, a slurry in which ceramic powder is dispersed in water is prepared, and in this slurry, a nickel salt solution and an alkaline aqueous solution are added, and nickel hydroxide is adhered to the surface of the ceramic powder. By applying the heat treatment and pulverization treatment, it is possible to obtain a ceramic powder in which nickel and / or nickel compounds are present on the surface and / or surface layer as described above.

  The temperature applied in the above heat treatment is preferably 500 ° C. or more and 1000 ° C. or less. Within this range, the internal electrode is particularly effective for thinning and improving the coverage. When the heat treatment atmosphere is reducible, part or all of the nickel compound is reduced, and as a result, nickel metal is always present on the surface and / or surface layer of the ceramic powder.

  The ceramic powder preferably has not only nickel and / or a nickel compound but also a rare earth element compound on its surface and / or its surface layer. As the rare earth element compound, at least one of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y can be used. The presence of the rare earth element compound on the surface and / or surface layer of the ceramic powder makes it possible to maintain the effect of suppressing the sintering of the internal electrodes 3 and 4 to a higher temperature range. It is considered that the rare earth element acts to make the nickel and / or nickel compound more easily stay on the surface of the ceramic powder or in the surface layer.

  Thus, the ceramic powder in which not only nickel and / or nickel compound but also a rare earth element compound is present on the surface and / or surface layer causes nickel and / or nickel compound and rare earth element compound to adhere to the ceramic powder. Then, the ceramic powder is obtained by subjecting it to heat treatment and pulverization treatment.

  As a method for adhering nickel and / or nickel compound and rare earth element compound to ceramic powder, for example, a slurry in which ceramic powder is dispersed in water is prepared, and a solution containing nickel salt and rare earth element salt in the slurry There is a method in which nickel hydroxide and rare earth element hydroxide are adhered to the ceramic powder. A more specific example of this method is described in Experimental Example 2 described later.

  As another method for adhering nickel and / or nickel compound and rare earth element compound to ceramic powder, an organic fatty acid salt solution containing nickel and rare earth element is prepared, and this is a slurry in which ceramic powder is dispersed in water There is a method in which the organic solvent is volatilized and the fatty acid salt containing nickel and a rare earth element is adhered to the ceramic powder after being put in and sufficiently dispersed. A more specific example of this method is as follows.

  First, for example, an octylate is prepared as a fatty acid salt of Dy and Ni. Next, 50 g of barium titanate powder as a ceramic powder is dispersed in 500 cc of acetone and sufficiently stirred to prepare a slurry. Next, Dy and Ni octylate weighed in advance and dissolved in acetone are added to this slurry and stirred for 30 minutes, whereby octylate and slurry are mixed. Let them get used to it. Thereafter, a rotary evaporator is applied to the mixture of octylate and slurry to volatilize acetone. Thereby, barium titanate powder to which octylates of Dy and Ni are attached can be obtained.

  Even in the case of the ceramic powder having the rare earth element compound attached thereto, the temperature of the subsequent heat treatment is preferably 500 ° C. or more and 1000 ° C. or less.

  The particle size of the ceramic powder contained in the conductive nickel paste according to the present invention is preferably 50 nm or less. This is because if the thickness exceeds 50 nm, the effects of thinning the internal electrode and improving the coverage of the internal electrode may be hindered.

  Moreover, it is preferable that the particle size of the nickel powder contained in the conductive nickel paste according to the present invention is 0.2 μm or less. By selecting the particle size of the nickel powder in this way, the thickness of the conductive nickel paste film can be reduced to 0.25 to 0.3 μm, and as a result, the internal electrode can be made thinner. Because.

  In the present specification, “particle diameter” for various powders is an average value obtained by arithmetically averaging the particle diameters for 1000 objects, as measured by scanning electron microscope (SEM) photographs. .

  Next, experimental examples carried out to confirm the effects of the present invention will be described.

1. Experimental example 1
As the ceramic powder to be contained in the conductive nickel paste, the ceramic powder according to each sample as shown in Table 1 was prepared.

  In Table 1, “ceramic powder type” indicates the composition of the ceramic constituting the used ceramic powder. “Amount of nickel component” indicates the molar ratio of the nickel component present on the surface and / or surface layer of the ceramic powder to 100 parts by mol of the ceramic powder.

First, a slurry in which ceramic powder having a particle size of 30 nm having the composition shown in “Ceramic powder type” in Table 1 was dispersed in water was prepared. Next, a slurry in which nickel chloride is dissolved in water and a solution in which sodium hydroxide is dissolved in water are added to the slurry at 10 cm ³ / min, respectively, and these are mixed to cause a neutralization reaction. As a result, nickel hydroxide was deposited on the surface of the ceramic powder.

  After the addition of the aqueous solution as described above, the mixture was aged for 10 to 30 minutes, and then the supernatant of the reaction solution was replaced with pure water several times to wash the powder. Further, after the water was replaced with acetone, the powder was dried in an oven set at a temperature of 80 ° C. for about 2 hours.

At this stage, the surface of the ceramic powder was examined with a transmission electron microscope (TEM) and a composition analyzer (EDX) using energy dispersive X-ray spectroscopy attached thereto. It was confirmed that was attached. In addition, from what is estimated to be nickel hydroxide by EDX, when the “ceramic powder seed” is, for example, BaTiO ₃ , there was a place where Ba and Ti were detected. This is because it was applied to the BaTiO ₃ powder, and at this stage, nickel and the BaTiO ₃ powder were not reacted. Moreover, although Cu was detected a little, this originated in Cu mesh for fixing ceramic powder in TEM observation.

Sample 17 shown in Table 1 is a comparative example, and BaTiO ₃ powder having no nickel component on the surface or surface layer is used as the ceramic powder. Therefore, Sample 17 was not subjected to the above-described nickel hydroxide adhesion treatment or heat treatment described later.

  Sample 2 uses ceramic powder to which the dried nickel hydroxide is adhered as described above, and the following heat treatment was not performed on this.

  For samples 1 and 3 to 16, excluding samples 2 and 17, the ceramic powder to which the nickel hydroxide dried as described above was attached is shown in “Heat treatment temperature” and “Heat treatment time” in Table 1, respectively. Heat treatment in the atmosphere at different temperatures and times.

For sample 12, after this heat treatment, the ceramic powder was reduced to a temperature of 800 ° C. and oxygen partial pressure (PO ₂ ) [MPa] was log (PO ₂ ) = − 16. Heat treated for 3 hours.

  Next, Samples 1 and 3 to 16 subjected to the heat treatment as described above were subjected to a pulverization treatment with a ball mill for 12 hours after the heat treatment.

  In the column of “Presence state of nickel component” in Table 1, “form” and “location” of the nickel component are shown.

  Regarding the “form” of the nickel component, it is nickel oxide that is labeled “oxide”, nickel hydroxide that is labeled “hydroxide”, and “metal”. Is metallic nickel. The “morphology” of these nickel components is estimated from the heat treatment temperature and the corresponding equilibrium oxygen partial pressure. For example, when heat treatment is performed at a temperature of 1000 ° C. in the atmosphere, it is natural that the “form” is derived from the equilibrium oxygen partial pressure. Since it can be estimated that it is an oxide, it is indicated as “oxide” in Table 1.

  Regarding the “location” of the nickel component, it was confirmed by TEM observation whether it remained attached to the surface of the ceramic powder or reacted to form a solid solution (diffusion). "" Indicates that the surface adheres to the surface of the ceramic powder, and "surface layer" indicates that the surface is dissolved (diffused) in the surface layer of the ceramic powder.

  Next, nickel powder having a particle size of 0.15 μm was prepared, and the nickel powder and the ceramic powder according to each sample shown in Table 1 were blended so as to have a weight ratio of 90:10. On the other hand, an organic vehicle prepared such that the ethylcellulose binder and terpineol are in a weight ratio of 10:90 is prepared, and the above-described powder component, the organic vehicle and terpineol are mixed in a weight ratio of 50:40:10. The conductive nickel paste according to each sample in a well dispersed state was obtained by carefully mixing and carrying out a dispersion mixing process using a three roll mill.

On the other hand, an organic solvent such as a polyvinyl butyral binder and ethanol was added to a powder of a BaTiO ₃ -based non-reducing dielectric ceramic composition having a known composition, and wet-mixed by a ball mill to prepare a ceramic slurry. Next, this ceramic slurry was formed into a sheet by a doctor blade method to obtain a ceramic green sheet having a thickness of 5.0 μm.

  Next, on the ceramic green sheet, the conductive nickel paste according to each sample described above was screen-printed to form a conductive nickel paste film serving as an internal electrode. At this time, the thickness of the conductive nickel paste film was adjusted to 0.5 μm by adjusting the thickness of the screen pattern.

  Next, a plurality of ceramic green sheets are laminated and pressure-bonded to produce a laminated block in which 10 layers of conductive nickel paste films serving as internal electrodes are formed, and the laminated block is cut into a predetermined dimension, A raw multilayer body serving as a component body of the multilayer ceramic capacitor was obtained, and this was fired at a temperature of 1150 ° C. in a reducing atmosphere to obtain a sintered component body.

  Thus, about the component main body which concerns on each sample obtained in this way, the coverage of the internal electrode and the thickness of the internal electrode were measured, respectively. The results are shown in the columns of “Internal electrode coverage” and “Internal electrode thickness” in Table 1, respectively.

  Referring to Table 1, according to Samples 1 to 16, it can be seen that high coverage is obtained even if the thickness of the internal electrode is small. In particular, according to Samples 1 to 14 having a nickel component amount of 5 to 100 mol parts, it can be seen that the effects of thinning the internal electrode and improving the coverage are higher.

  Further, comparing Samples 1 to 11 and Sample 12, whether the nickel component present on the surface and / or surface layer of the ceramic powder is a nickel compound or metallic nickel, the thin layer of the internal electrode It can be seen that substantially the same effect can be exerted with regard to the improvement of coverage and coverage.

  Further, comparing Samples 1 to 12, Sample 13 and Sample 14, it can be seen that there is substantially the same effect in reducing the thickness of the internal electrode and improving the coverage regardless of the composition of the ceramic powder.

  On the other hand, according to the sample 17, since the nickel component is not present on the surface or surface layer of the ceramic powder, it can be seen that the internal electrode is thick and the coverage is low.

2. Experimental example 2
As the ceramic powder to be contained in the conductive nickel paste, the ceramic powder according to each sample as shown in Table 2 was prepared.

  “Type” in “Ceramic powder” of Table 2 indicates the composition of the ceramic constituting the used ceramic powder, and “Particle size” indicates the particle size of the used ceramic powder. “Amount of nickel component” indicates the molar ratio of the nickel component present on the surface and / or surface layer of the ceramic powder to 100 parts by mol of the ceramic powder. “Type” in “rare earth element” indicates the type of rare earth element contained in the rare earth element compound present on the surface and / or surface layer of the ceramic powder, and the “component amount” indicates the ceramic of the rare earth element compound. The molar ratio with respect to 100 mol parts of the powder is shown.

  First, 50 g of ceramic powder having the composition and particle size shown in “Ceramic powder” in Table 2 was dispersed in 1 liter of pure water and sufficiently stirred to prepare a slurry.

  On the other hand, an aqueous solution in which nickel chloride and a rare earth element chloride were dissolved, and an aqueous sodium hydroxide solution were prepared. Here, for the aqueous solution in which the former nickel chloride and the rare earth element chloride are dissolved, nickel chloride is contained in a molar part shown in “amount of nickel component” in Table 2 with respect to 100 molar parts of the ceramic powder. In addition, the rare earth element chloride shown in “kind” of “rare earth element” in Table 2 was included with the molar part shown in the “component amount”. About the latter sodium hydroxide aqueous solution, 0.1 mol part sodium hydroxide was contained with respect to 100 mol parts of ceramic powder.

Next, while sufficiently stirring the slurry, an aqueous solution in which nickel chloride and a rare earth element chloride are dissolved and an aqueous sodium hydroxide solution are added to the slurry at 10 cm ³ / min. Then, a nickel hydroxide and a rare earth element hydroxide were adhered to the surface of the ceramic powder by causing a neutralization reaction. At this time, in order to make the same amounts of the aqueous solution in which nickel chloride and rare earth element chloride are dissolved and the sodium hydroxide aqueous solution, the amounts of nickel chloride and rare earth element chloride in the former aqueous solution are the same. The concentration was adjusted.

  After the addition of the aqueous solution as described above, the mixture was aged for 10 to 30 minutes, and then the supernatant of the reaction solution was replaced with pure water several times to wash the powder. Furthermore, after the water was replaced with acetone, the powder was dried in an oven set at a temperature of 80 ° C. for about 2 hours.

The powder according to each sample subjected to the above treatment was heat treated under the conditions shown in the columns of “heat treatment temperature”, “heat treatment atmosphere” and “heat treatment time” in Table 2. Samples 38 and 39 were heat-treated in a N ₂ atmosphere at a temperature of 1000 ° C. for 2 hours, and then heat-treated in a 0.1% H ₂ + N ₂ atmosphere at a temperature of 500 ° C. for 3 hours.

  Thereafter, the powder according to each sample was pulverized in a ball mill for 12 hours.

  In the columns of “Nickel component presence state” and “Rare earth component presence state” in Table 2, the “form” and “location” of the nickel component are the same as in the corresponding columns of Table 1, respectively. , As well as the “form” and “location” of the rare earth element component.

  Next, using the ceramic powder according to each sample shown in Table 2, the same operation as in Experimental Example 1 was performed to obtain a conductive nickel paste.

  On the other hand, a ceramic green sheet having a thickness of 5.0 μm is produced through the same operation as in Experimental Example 1, and then a conductive material having a thickness of 0.5 μm made of a conductive nickel paste according to each sample is formed on the ceramic green sheet. The sintered component body is formed by sequentially forming a plurality of ceramic green sheets, pressing and stacking a plurality of ceramic green sheets, and then cutting the stacked block, and firing the resulting laminate. Got.

  With respect to the component main body related to each sample thus obtained, the coverage of the internal electrode and the thickness of the internal electrode were measured by the same method as in Experimental Example 1. The results are shown in the columns of “Internal electrode coverage” and “Internal electrode thickness” in Table 2, respectively.

  In Table 2, the amount of nickel component is different between samples 21 to 26. Therefore, if the samples 21 to 26 are compared, the magnitude of the effect due to the difference in the nickel component amount can be grasped. That is, in the samples 23 to 26 in which the nickel component amount is in the range of 1 to 100 mol parts, the internal electrode coverage is improved and the internal electrode coverage is improved as compared with the samples 21 and 22 in which the nickel component amount is less than 1 mol part. It can be seen that the layer thickness is reduced.

  Between the samples 27 to 30, the component amount of Dy, which is a rare earth element, is varied. Therefore, if the samples 27 to 30 are compared, it is possible to grasp the magnitude of the effect due to the difference in the rare earth element component amount. That is, according to the samples 28 to 30 in which the rare earth element component amount is in the range of 0.01 to 10 mol parts, the internal electrode coverage is improved as compared with the sample 27 of less than 0.01 mol parts, and the internal electrodes It can be seen that the layer thickness is reduced.

  Although not shown in Table 2, when the component amount of Dy as a rare earth element is increased to 15 mole parts, the dielectric constant temperature characteristic of the obtained multilayer ceramic capacitor does not satisfy the B characteristic of JIS standard. A malfunction occurred. From this and the fact described above, it is understood that the amount of the rare earth element component is preferably in the range of 0.01 to 10 mol parts.

  The heat treatment temperatures are different between the samples 31 to 34. Therefore, if it compares between the samples 31-34, the preferable range about heat processing temperature can be found. That is, in Samples 32 and 33 having a heat treatment temperature in the range of 500 to 1000 ° C., particularly good results are obtained with respect to the internal electrode coverage and the internal electrode thickness. In the sample 31 having a heat treatment temperature as low as 300 ° C., nickel diffusion does not proceed sufficiently, and nickel reduction proceeds in a low temperature range, which is sufficient for improving internal electrode coverage and thinning the internal electrode. This is considered to be the reason why it was not possible to have a positive effect. On the other hand, in the sample 34 having a high heat treatment temperature of 1200 ° C., the grain growth progressed too much and a fine dielectric could not be obtained, so that a sufficient effect was obtained for improving the internal electrode coverage and thinning the internal electrode. Probably not.

  Among the samples 35 to 37, the particle size of the ceramic powder is different. Therefore, if the samples 35 to 37 are compared, the magnitude of the effect due to the difference in the particle size of the ceramic powder can be grasped. That is, Samples 35 and 36 in which the particle size of the ceramic powder is 10 nm and 50 nm, respectively, have a relatively large effect on the improvement of the internal electrode coverage and the thinning of the internal electrode. It can be seen that these effects are relatively small in the sample 37 having a large diameter of 70 nm.

  Samples 38 and 39 differ from the other samples in that the reduction treatment was performed in the heat treatment stage. Comparing these samples 38 and 39 with other samples, it can be seen that even if a reduction treatment is applied, substantially the same effect as that obtained when such a reduction treatment is not performed can be obtained. The reduction treatment is intended to suppress shrinkage of the internal electrode accompanying the shrinkage of the nickel compound during firing by reducing in advance the excess nickel compound that has not sufficiently diffused into the ceramic powder.

  In the sample 40, a ceramic powder made of a material in which a part of Ti is substituted with Zr instead of barium titanate is used. Comparing this sample 40 with other samples, substantially the same effect can be obtained even when a ceramic powder made of a material in which a part of Ti is replaced with Zr instead of barium titanate is used. I understand that

  Sample 41 does not contain a rare earth element component. Comparing this sample 41 with samples 25, 29, 30, 33, and 36 that differ only in the inclusion of rare earth elements, the inclusion of the rare earth element compound improves internal electrode coverage and reduces the thickness of the internal electrodes. It turns out that an effect is further heightened.

Claims (8)

  A conductive nickel paste comprising nickel powder, ceramic powder having nickel and / or a nickel compound on the surface and / or surface layer thereof, and an organic vehicle.   2. The conductive nickel paste according to claim 1, wherein the ceramic powder has the nickel and / or nickel compound attached to a surface thereof, and the nickel compound is nickel hydroxide and / or nickel oxide.   The conductive nickel paste according to claim 1, wherein the ceramic powder has the nickel compound diffused in a surface layer thereof, and the nickel compound is nickel oxide.   2. The conductive nickel paste according to claim 1, wherein the amount of the nickel and / or nickel compound is 5 to 100 parts by mole with respect to 100 parts by mole of the ceramic powder.   The conductive nickel paste according to claim 1, wherein a rare earth element compound is further present on the surface and / or surface layer of the ceramic powder.   6. The conductive nickel paste according to claim 5, wherein an amount of the nickel and / or nickel compound is 1 to 100 mol parts with respect to 100 mol parts of the ceramic powder.   6. The conductive nickel paste according to claim 5, wherein an amount of the rare earth element compound is 0.01 to 10 mol parts with respect to 100 mol parts of the ceramic powder.   The conductive nickel paste according to claim 1, wherein the ceramic powder has a particle size of 50 nm or less.

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