JPH04329209A - Electrically conductive paste - Google Patents

Abstract

PURPOSE:To provide an electrically conductive paste capable of suppressing the occurrence of the exfoliation or cracking between the ceramic material and the internal electrode durning the burning step performance in manufacturing a laminate ceramic capacitor. CONSTITUTION:By kneading together a mercury-containing metal powder, an organic binder and a solvent and causing a mercury-titanium alloy to be contained into the thus kneaded mass, the degree of adhesion between the internal electrode and the ceramic material is improved to prevent exfoliation, cracking, etc. Preferably, titanium in the mercury-titanium alloy is contained 0.1 to 0.6wt.% with respect to mercury.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a conductive paste.
In particular, it relates to a metal paste for internal electrodes used in multilayer ceramic capacitors.

0002

[Prior Art] Multilayer ceramic capacitors are generally manufactured by mixing ceramic powder with an organic binder, processing the mixture into a sheet, printing internal electrodes using conductive metal paste, laminating and press-bonding these, and then It is manufactured by cutting and firing to form an external electrode connected to an internal electrode. Conventionally, a conductive metal paste used for this type of internal electrode is manufactured by mixing metal powder such as silver or palladium with a vehicle consisting of an organic binder and a solvent, and kneading the mixture using a three-roll mill or the like.

0003

In the manufacturing process of the multilayer ceramic capacitor described above, the ceramic powders react with each other during the firing process to cause sintering shrinkage, thereby making the ceramic portion denser. At the same time, the metal powder in the conductive paste applied as the internal electrode is also sintered and shrunk, forming an internal electrode layer. However, since chemical bonding does not occur between ceramic and metal, the bond between ceramic and internal electrodes is weak, and the difference between sintering shrinkage of ceramic and sintering shrinkage of metal paste in internal electrodes during the firing process or thermal expansion Due to the difference, there is a problem in that peeling between the ceramic and the internal electrodes or cracks due to stress inside the ceramic occur. An object of the present invention is to provide a conductive paste that suppresses peeling between the ceramic and internal electrodes and cracks in the ceramic.

0004

[Means for Solving the Problems] The conductive paste of the present invention contains a silver-titanium alloy in a conductive paste made by kneading a metal powder containing silver, an organic binder, and a solvent. In this case, the ratio of silver titanium alloy to silver is 0.1 to 6
．． It is preferable to contain 0% by weight.

[0005]

[Function] According to the present invention, by containing a silver-titanium alloy, the silver-titanium alloy in the conductive paste exists as a silver-titanium alloy in the internal electrode, and the titanium part is oxidized at the contact part with the ceramic. The titanium oxide portion and the silver-titanium alloy are formed continuously, increasing the bonding strength between the ceramic and the internal electrodes.

[0006]

[Example] Next, the present invention will be explained. Table 1 shows examples according to the present invention (compositions I to V) and conventional examples (composition VI).
The composition of the conductive paste is shown below.

[0007]

[Table 1]

[0008] The palladium powder shown in Table 1 has a particle size of 0.1
~ 0.3 μm, and the silver powder used had a particle size of 0.2 to 0.5 μm. The silver titanium alloy powder has a particle size of 0.2 to 0.
A 5 μm one was used. The organic vehicle used was a mixture of ethyl cellulose resin and a solvent such as terpineol.

[0009] Then, palladium powder and silver powder in the amounts shown in Table 1 were mixed in advance, and silver titanium alloy powder was mixed to obtain a mixed powder. Furthermore, mix the mixed powder in an organic vehicle,
The mixture was mixed in a three-roll mill to obtain conductive pastes having compositions IV to V. Next, each conductive paste was printed in a predetermined pattern on a lead-based dielectric ceramic green sheet with a thickness of 20 μm, and 60 layers were laminated, crimped, and cut to obtain an unfired multilayer ceramic capacitor. After removing the binder from an unfired multilayer ceramic capacitor at 300°C to 400°C, the temperature was raised at a rate of 100°C/Hr, and the temperature was increased to 1.
After holding at 000°C for 2 hours, the temperature was raised at 100°C/Hr to obtain a multilayer ceramic capacitor element.

The resulting laminated ceramic capacitor elements were examined for peeling and cracking among 10,000 pieces. The results are shown in Table 2.

[0011]

[Table 2]

As shown in Table 2, peeling and cracking can be effectively suppressed by using a conductive paste containing 0.1 to 0.6% by weight of silver titanium alloy powder based on silver. .

[0013] As shown in Table 3 and FIG. 1, if the silver titanium alloy powder is contained in an amount greater than 6.0% by weight, electrode breakage and the like occur, resulting in deterioration of electrical characteristics.

[0014]

[Table 3]

[0015]

Effects of the Invention As explained above, in the present invention, by containing a silver-titanium alloy, the silver-titanium alloy in the conductive paste exists as a silver-titanium alloy in the internal electrode, and the titanium alloy exists in the internal electrode as a titanium alloy in the contact area with the ceramic. The part is oxidized and the titanium oxide part and silver-titanium alloy are formed continuously, increasing the bonding strength between the ceramic and the internal electrode, and preventing peeling and cracking due to sintering shrinkage and differences in thermal expansion coefficients. There is an effect that can be done.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the relationship between the ratio of silver titanium alloy to silver and its electrical properties in an example of the present invention.

Claims (2)

[Claims] 1. A conductive paste made by kneading a metal powder containing silver, an organic binder, and a solvent, the conductive paste containing a silver-titanium alloy. [Claim 2] Silver-titanium alloy with a ratio of 0.1 to silver
The conductive paste according to claim 1, containing 6.0% by weight.