CN109616242B

CN109616242B - End electrode silver paste without plating for inductor

Info

Publication number: CN109616242B
Application number: CN201910134275.7A
Authority: CN
Inventors: 张韶鸽; 杨玉华
Original assignee: Zhaoqing Chenye Electronics Co ltd
Current assignee: Zhaoqing Chenye Electronics Co ltd
Priority date: 2018-11-05
Filing date: 2019-02-22
Publication date: 2020-07-10
Anticipated expiration: 2039-02-22
Also published as: CN109215843A; CN109616242A

Abstract

The invention relates to the technical field of electronic materials for electronic components, in particular to silver paste for an inductor plating-free end electrode. The weight percentage composition is as follows: 25-35% of spherical silver powder, 15-25% of flake silver powder, 10-15% of silver oxide powder, 2-4% of glass powder and other inorganic materials and 20-25% of organic carrier, wherein the sum of the weight percentages of all the substances is 100%. The silver paste for the non-plated end electrode of the inductor produced by the silver paste has the advantages of high drying strength, good end-capped appearance quality, compact electrode layer after sintering, high end adhesion, no sheet jump meeting the SMT packaging requirement, low resistivity, small direct current Resistance (RDC), environmental protection, no plating and environmental protection.

Description

End electrode silver paste without plating for inductor

Technical Field

The invention relates to the technical field of electronic materials for electronic components, in particular to plating-free end electrode silver paste for an inductor and a preparation method thereof.

Background

With the rapid development of electronic information industries such as mobile phones, computers and the like, the domestic electronic component market is met with a new rapid development opportunity, and in the aspect of laminated inductive elements, with the increasingly mature production process technology of domestic manufacturers, nearly 50% of inductive products in the world belong to the manufacture of China, and the direct connection and the weather become companies with the number of two of the output and the quality of the global inductor. In the forming of inductance products, most of terminal electrodes after end burning are still used in an electroplating process, the electroplating process has great environmental protection disadvantages due to the pollution of nickel to the environment, and electroplating production is forbidden in most of domestic areas at present.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the plating-free end electrode silver paste for sensing, which is free of plating, environment-friendly and excellent in electrical property.

In order to solve the technical problems, the invention provides the technical scheme that: the plating-free end electrode silver paste for the inductor comprises the following components in parts by weight: 25-35% of spherical silver powder, 15-25% of flake silver powder, 10-15% of silver oxide powder, 2-4% of glass powder and other inorganic materials and 20-25% of organic carrier, wherein the sum of the weight percentages of all the substances is 100%.

Further: in the plating-free end electrode silver paste for the inductor, the ball silver is self-developed by the company, and has high sphericity, good fluidity and 0.2-0.6 micron particle size. The flaky silver is self-developed by the company, the flaky silver is well flaky, the silver flake is thin, and the particle size is 0.5-0.8 micrometer. The nano silver oxide is self-developed by the company, has good flaking property, thin silver flakes and a particle size of 50-150 nanometers. The glass powder is borosilicate system glass with the particle size of 2-5 microns, and the inorganic material is at least one of ferric oxide, copper oxide, zinc oxide, silicon oxide and boric acid. The organic carrier adopts ethyl cellulose resin as an adhesive of the organic carrier, and the content of the ethyl cellulose resin in the organic carrier is 3-10%; a small amount of rosin is added to improve the viscosity of the slurry and contribute to improving the drying strength, and the content of the rosin in the organic carrier is 0.1-1%; one or more alcohol solvents are adopted as main solvents, and the content of the main solvents in the organic carrier is 50-60%; one or more ester solvents are adopted as a cosolvent, and the content of the cosolvent in an organic carrier is 20-40%; the organic carrier for preparing the electrode slurry provides excellent printing performance for the slurry, and improves the appearance quality and the drying strength of the end-capped product.

The preparation method of the plating-free end electrode silver paste for the inductor comprises the following steps: the silver paste is prepared according to the conventional slurry production process flow, namely: firstly, preparing resin, rosin and a solvent into an organic carrier; and then, preparing the slurry according to the formula, mixing by adopting a power mixing stirrer, fully grinding the roller by utilizing a three-roller grinder to obtain a certain fineness and viscosity requirement, and finally filtering, adjusting and bottling to obtain the silver end electrode slurry.

Compared with the prior art, the preparation method has the advantages that the organic carrier is prepared from ethyl cellulose, rosin, alcohols and ester solvents according to a certain formula, a good rheological property of the paste is provided, the spherical silver with high sphericity is matched with the flake silver powder, so that the good flowing property of the paste is ensured, and a good thixotropic property of the paste is provided, so that the paste does not sag after being pasted with silver and has a smooth end, the appearance quality of an electrode end of an inductance product is good, and the problems of sagging, sharp heads, pits, pinholes and the like caused by the matching problem of the thixotropic property and the fluidity of the electrode paste in the prior art are avoided. A borosilicate glass system is adopted, bismuth and lead are not contained, the environment-friendly requirement is completely met, the electrode layer is compact after sintering, the end adhesion is good, and the technical requirement of the SMT packaging jump sheet process is met; the surface of the electrode has no glass floating, the electrode has good weldability, conditions are provided for the plating-free performance requirement of the slurry, and the nano silver oxide which is self-developed by the company is used in the formula, so that the electrode activity of the slurry after sintering is high, the weldability is good, and the plating-free production process of the slurry is realized.

The specific implementation mode is as follows:

the main point of the invention is that the plating-free environment-friendly terminal electrode silver paste with good end-capped appearance quality and excellent electrical performance is obtained by matching spherical silver with extremely high sphericity with flake silver powder, doping nano silver oxide powder in a certain proportion, reasonably proportioning borosilicate glass powder, other inorganic additive materials and organic carrier and selecting proper particle size. The inductor product produced by the end electrode silver paste meets the requirement of chip skipping in the SMT packaging process. The invention discloses a plating-free end electrode silver paste for an inductor, which comprises the following steps: firstly, a self-developed organic carrier is adopted, so that a good rheological property and strong drying strength are provided for the slurry; the electrode paste adopts the company to research and develop the collocation of the spherical silver powder and the flake silver powder, provides the paste with good thixotropic property, enables the paste to have good end-capping appearance, and is compact in electrode layer and excellent in electrical property after being fired. And thirdly, the electrode slurry is prepared by adopting the company to research and develop nano silver oxide, so that the electrode activity of the slurry after sintering is high, the weldability is good, and the plating-free production process is realized. And fourthly, the electrode slurry adopts the company to research and develop borosilicate glass powder by self, so that the slurry is sintered at low temperature, and a good end adhesive force is provided for the slurry under the condition that the glass content is lower than 3%, so that the SMT jump requirement of the produced inductance product during chip packaging is met. The invention is further illustrated by the following examples, which are not intended to limit the invention, and other silver paste formulations selected under the inventive concept can be made according to local conditions without substantial influence on the result.

The formulation of the borosilicate glass frit in the present invention is shown in table 1.

Table 1:

the formulation design of the best embodiment of the invention is shown in table 2, and the glass powder selected in the embodiment can be any scheme in table 1:

table 2:

the inorganic oxide is at least one of ferric oxide, nickel oxide, copper oxide, zinc oxide and boric acid. They may be mixed in any ratio, which is a means commonly used by those skilled in the art.

The silver end electrode slurry is prepared from the proportioning materials of the embodiment according to the conventional slurry production process flow, namely the slurry is prepared according to the formula, mixed by a power mixing stirrer, fully ground by a three-roll grinder to reach certain fineness and viscosity requirements, filtered, adjusted and bottled to form the silver end electrode slurry. The obtained silver paste is also used for preparing inductance products according to a laminated inductance preparation method commonly used by a person skilled in the art, 10 products are obtained in each example, and the test performance of the products is shown in table 4:

table 4:

as can be seen from Table 4, the slurry obtained by the present invention has good bondability to M L CI ceramic bodies, dense fired electrodes and excellent electrode performance.

The above examples of the present invention are merely examples for clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. The plating-free end electrode silver paste for the inductor comprises the following components in parts by weight: 25-35% of spherical silver powder, 15-25% of flake silver powder, 10-15% of nano silver oxide powder, 2-4% of glass powder and other inorganic materials and 20-25% of organic carrier, wherein the sum of the weight percentages of all the substances is 100%;

the particle size of the spherical silver powder is 0.2-0.6 micron; the particle size of the flaky silver is 0.5-0.8 micrometer; the grain diameter of the nano silver oxide is 50-150 nm; the other inorganic material is at least one of ferric oxide, copper oxide, zinc oxide, silicon oxide and boric acid.

2. The plating-free end electrode silver paste for the inductor according to claim 1, wherein: the glass powder is borosilicate system glass with the particle size of 2-5 microns.

3. The plating-free end electrode silver paste for the inductor according to claim 1, wherein: the organic carrier comprises 3-10 wt% of ethyl cellulose resin, 0.1-1 wt% of rosin, 50-60 wt% of alcohol solvent and 20-40 wt% of ester solvent, wherein the wt% of each component is 100%.