JPS61158122A - Conductive paste - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a conductive paste containing Ni as a main component and fired in a non-oxidizing atmosphere.

[Conventional technology]

In multilayer ceramic capacitors manufactured by firing in a non-oxidizing atmosphere, both internal and external electrodes are made using the same conductive paste. And the conductive powder in this conductive paste.

It consisted only of Ni powder.

A method for manufacturing this type of laminated ceramic densifier will be explained. First, an unsintered porcelain sheet is made using a ceramic material, and an internal electrode pattern is printed on it using conductive paste. Next, several of these sheets are stacked and cut. Next, this is fired at a temperature of 1100 to 1300°C in a non-oxidizing atmosphere.

Part of the internal electrode is exposed on the side surface of the laminate thus obtained. Apply a conductive paste according to the external electrode pattern on this surface, and apply it in a non-oxidizing atmosphere to
A multilayer ceramic capacitor is obtained by firing at a temperature of 150°C.

[Problem that the invention seeks to solve]

The multilayer ceramic capacitor manufactured in this manner has a portion in which the electrical connection between the end portion of the internal electrode exposed on the side surface and the external electrode that is brought into contact with the end portion is poor. As a result, the multilayer ceramic capacitor has dielectric loss ta
The average value of nδ was generally high (generally just around the predetermined standard value, but there were some cases at the end of the distribution that exceeded the predetermined standard value).

An object of the present invention is to solve the above-mentioned problems in conventional Ni conductive pastes. That is, all the ends of the internal electrodes are completely connected to the external electrodes, and as a result, the average value of the dielectric loss tan δ of the multilayer ceramic capacitor chip is lower than the predetermined standard value, and as a result, all the multilayer ceramic capacitors meet the predetermined standard value. The purpose is to ensure that the temperature is below the standard value.

[Means to solve the problem]

The conductive paste of the present invention is composed of a conductive powder and a binder, and the conductive powder is composed of 80 to 97% by weight of Ni powder and 3 to 20% by weight of Co powder. The binder is made of conventionally known binders such as ethyl cellulose and butyl calpitol.

[For production]

This conductive paste is used to make either an internal electrode or an external electrode of a multilayer ceramic capacitor, and a conventional Ni paste is used for the other electrode. For example, when the conductive paste of the present invention is used for the internal electrodes of a multilayer ceramic capacitor, the external electrodes may contain Ni.
Use paste. Conversely, when the conductive paste of this invention is used for external electrodes, N
Use iPaste.

If a conductive paste for internal and external electrodes is used in this way, when baking the external electrodes.

From the electrode side made with the conductive paste of this invention,
CO diffuses to the other electrode side which does not contain Co, and an N1-Co gold alloy is formed in a continuous complete solid solution state between the two electrodes.

As a result, the electrical connection between the two electrodes becomes good, and the dielectric loss tan δ of the multilayer ceramic capacitor can be reduced.

' The reason for limiting the composition ratio in the conductive powder of the conductive paste according to the present invention as described above is as follows. When the proportion of Co powder in the conductive powder of the conductive paste is small, C between the inner and outer electrodes.

Since the difference in the concentration of Co is reduced, diffusion of Co from one electrode to the other electrode becomes less likely to occur when the external electrodes are baked. For this reason, a poor electrical connection between the two electrodes as described above is formed.

As a result, the dielectric loss ta of the multilayer ceramic capacitor
nδ is generally high, and all multilayer ceramic capacitors cannot satisfy the specified standard value for dielectric loss tanδ.On the other hand, when the proportion of Co powder in the conductive powder is high, electrodes using Ni paste Therefore, the equivalent series resistance ESI of the multilayer ceramic capacitor becomes high. Therefore, from these points, the concentration of Co powder in the conductive powder is set to 3 to 20% by weight. It needs to be within the range of

[Example 1] Next, embodiments of this invention will be described.

Ni powder with a purity of 99.9% and C as conductive powder.

The powder was blended with ethyl cellulose and butyl calpitol as binders in the proportions shown in Table 1. These were mixed with a crusher for 3 hours.

Thereafter, the mixture was kneaded in a roll mill for 1 hour to prepare 3 types of conductive pastes A, B, and C.

These three types of conductive pastes were used in the following manner to produce 500 laminated ceramic capacitors each.

An internal electrode pattern was printed on a BaTiO3-based green sheet using each of the three types of conductive pastes, and the sheets were laminated to produce an unfired laminated chip. These 2
1200% in a N2 gas atmosphere containing H2 gas.
Calcined at a temperature of °C. Next, 100g of Ni powder and Cab
, Bad.

5i02 glass frit 3g and the binder 10
A conventional Ni paste made by mixing 0 g of
I applied it to the thickness of I. Furthermore, these were baked in an N2 gas atmosphere containing 2% H2 gas while maintaining a temperature of 1100° C. for 1 hour to produce three types of multilayer ceramic capacitors.

After leaving the multilayer ceramic capacitor made in this way at room temperature for one day, it was measured using a commercially available LCR meter (YHP427).
4A), the capacitance C (μF) and dielectric loss tan δ (%) at IKHz were measured.

Table 2 shows the average value, maximum value, and minimum value of the dielectric loss tan δ.

As is clear from the table, the maximum value of dielectric loss tan δ of a total of 1,500 multilayer ceramic capacitors is 2.2
%, and the dielectric loss tan δ of all capacitors was below the standard value of 3.0%. Incidentally, the capacitance C was in the range of 1.25 to 1.28 μF in all cases, and was within the standard of 1.0 μF.

[Example 2] 90 g of Ni powder and 10 g of CO powder as conductive powders, and 3 g of Cab, Bad, 5t02 glass powder, 7 g of ethyl cellulose and 93 g of butyl calpitol as binders were kneaded and mixed in the same manner as in Example 1. A conductive paste for external electrodes was made and used for the external electrodes of multilayer ceramic capacitors. In addition, the conductive paste for internal electrodes contained 100 g of Ni powder and 16 g of ethyl cellulose.

A conventional Ni paste mixed with 94 g of butyl calpitol was used.

Then, 500 multilayer ceramic capacitors of the same specifications were manufactured using the same method and conditions as in Example 1. Furthermore, the dielectric loss tan δ and capacitance C of these multilayer ceramic capacitors were measured using the same method and conditions as in Example 1. In this example as well, almost the same results as in Example 1 were obtained. This is shown in Table 2.

[Comparative example]

Using a conductive paste for internal electrodes made by kneading 100 g of Ni powder as a conductive powder and 16 g of ethyl cellulose and 94 g of butyl calpitol as a binder, a multilayer ceramic capacitor of the same standard was manufactured using the same method and conditions as in Example 1. 500 pieces were made. Furthermore, the dielectric loss tan was calculated using the same method for these pieces.
δ and capacitance C were measured. In this comparative example, the dielectric loss tan δ is higher overall than in the above example.
The average value is 3.1%.

It exceeded the standard value of 3.0%. The results are shown in Table 2.

Table 2 [Effects of the Invention] As explained above, when a multilayer ceramic capacitor is manufactured using the conductive paste according to the present invention as a conductive paste for one electrode, the state of connection between the external electrode and the internal electrode is improved. As a result, the dielectric loss t of these capacitors
It was possible to lower an δ and ensure that everything satisfied the predetermined standard range.

Claims (1)

[Claims] In conductive paste consisting of conductive powder and binder,
The conductive powder contains 80 to 97% by weight of Ni powder and 3% by weight of Co powder.
A conductive paste characterized by comprising: ~20% by weight.