Silver end electrode slurry for low temperature sintering MLCC

Abstract

The invention discloses a silver-end electrode slurry for low-temperature sintering MLCC, which comprises 65.0 to 85.0 wt.% of silver powder, 2.0 to 6.0 wt.% of glass powder and 9.0 to 33.0 wt.% of anorganic carrier, wherein the weight ratio of nano silver powder to microcrystalline silver powder in the silver powder is (0.5 to 2.0) to 1; the ratio of the weight sum of the nano silver powder andthe microcrystalline silver powder to the weight of flake silver powder is (2.0 to 7.0) to 1; the glass powder comprises 38.0 to 55.0 wt.% of ZnO, 5.0 to 25.0 wt.% of SiO2, 5.0 to 40.0wt.% of B2O3, 5.0 to 20.0 wt.% of Al2O3, 1.0 to 6.0 wt.% of K2O and 2.0 to 6.0 wt.% of Cu2O. While the slurry ensures good compactness of the silver layer and can also solve the problem of a void generated at a connection place by Kirkendall effects in the case of high-temperature sintering of internal and external electrodes.

Description

technical field [0001] The invention relates to the technical field of MLCC, in particular to a silver terminal electrode paste for low-temperature sintering MLCC. Background technique [0002] MLCC silver terminal electrode paste generally consists of three parts: organic carrier, glass powder and metal powder. The main function of the organic carrier is to disperse the metal powder and glass powder, so that the paste has a certain viscosity, leveling, and thixotropy. It is suitable for impregnation coating of capacitor elements; glass powder is used as a bonding phase, mainly to connect the metal electrode and the ceramic body of the capacitor during the sintering process, to ensure good adhesion between the external electrode and the ceramic body; the metal powder is formed after high temperature sintering The metal continuous electrode communicates with the inner electrode and serves as the terminal electrode material of the capacitor. [0003] The internal density of t...

AI Technical Summary

Problems solved by technology

[0004] The internal compactness is poor, and the electroplating solution is easy to corrode. In the later welding process, capacitor failure will occur, which seriously affects product quality.

[0005] The reason for the poor connection of the internal and external electrodes is that there is a regular gap at the connection of the internal and external electrodes, and the reason for this gap is mainly caused by the palladium-silver metal composition of the internal and external electrodes during the high-temperature sintering process of the electrodes. Since the internal electrodes are palladium-silver The electrode, the external electrode is a pure silver electrode. As the temperature rises, the two metals, palladium and silver, tend to be alloyed. There is a diffusion phenomenon of the two metals at the interface of the two electrodes, and the speed at which silver diffuses to palladium is palladium diffusion. to silver ten times faster, so this asymmetric diffusion phenomenon creates the void phenomenon

Although this kind of void phenomenon is ubiquitous, the existence of such voids has certain risks to the aging and adhesion of capacitors.

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