阅读说明：本技术 一种陶瓷滤波器表面金属化的方法 (Method for metallizing surface of ceramic filter ) 是由 王勇 刘芬 王一超 于 2020-12-14 设计创作，主要内容包括：本发明涉及一种陶瓷滤波器表面金属化的方法,主要包括以下步骤：将陶瓷滤波器表面进行清洗以除去滤波器表面的油污,然后将经过清洗后的陶瓷滤波器浸入到含硅/钛化合物的溶液中,充分浸泡使得滤波器表面包覆一层中间涂覆层膜；进一步通过化学镀铜或者化学镀银,然后进行电镀后在陶瓷滤波器表面形成性能良好的金属层；最后,将经过电镀后的陶瓷滤波器置于惰性气氛中,使得中间涂覆层反应生成二氧化硅,同时与表层的金属和基体陶瓷之间紧密结合。与现有产品相比,本发明所述的方案具有工艺过程简单和生产效率高的特点,同时所获得的产品具有良好的性能。(The invention relates to a method for metallizing the surface of a ceramic filter, which mainly comprises the following steps: cleaning the surface of a ceramic filter to remove oil stains on the surface of the filter, then soaking the cleaned ceramic filter into a solution containing a silicon/titanium compound, and fully soaking to coat the surface of the filter with an intermediate coating layer film; further forming a metal layer with good performance on the surface of the ceramic filter after electroplating through chemical copper plating or chemical silver plating; and finally, placing the electroplated ceramic filter in an inert atmosphere to enable the middle coating layer to react to generate silicon dioxide, and meanwhile, the silicon dioxide is tightly combined with the metal on the surface layer and the matrix ceramic. Compared with the existing products, the scheme of the invention has the characteristics of simple process and high production efficiency, and the obtained product has good performance.)

1. A method of surface metallization of a ceramic filter, characterized in that the method of surface metallization comprises the steps of:

(1) pretreatment: cleaning the surface of the ceramic filter by a physical or chemical method to remove oil stains on the surface of the filter;

(2) coating the intermediate layer on the surface of the ceramic filter: immersing the cleaned ceramic filter into a solution containing a silicon/titanium compound, and fully immersing to coat a layer of intermediate coating film on the surface of the filter;

(3) metallization of the ceramic surface: carrying out chemical copper plating or chemical silver plating on the ceramic filter coated by the silicon-containing compound to coat a metal layer on the surface of the ceramic filter;

(4) electroplating the surface of the ceramic: carrying out copper electroplating and silver electroplating on the ceramic filter subjected to surface metallization to obtain a good metal layer on the surface of the ceramic filter;

(5) and (3) heat treatment: and placing the electroplated ceramic filter in an inert atmosphere to enable the middle coating layer to react to generate silicon dioxide, and meanwhile, the silicon dioxide is tightly combined with the metal on the surface layer and the matrix ceramic.

2. A method of metallizing a surface of a ceramic filter according to claim 1, wherein: the physical cleaning method comprises one or more of ultrasonic cleaning, plasma cleaning, high-pressure water jet cleaning or electric pulse cleaning.

3. A method of metallizing a surface of a ceramic filter according to claim 1, wherein: the chemical cleaning comprises one or more of acid cleaning or alkali cleaning.

4. A method of metallizing a surface of a ceramic filter according to claim 1, wherein: the silicon-containing compound is silicate, silicate ester and silane coupling agent, and the titanium-containing compound is titanate, titanate and titanium-containing coupling agent.

5. A method of metallizing a surface of a ceramic filter according to claim 1, wherein: the solution containing the silicon/titanium compound is an aqueous solution or an alcoholic solution or a dispersion of one or more compounds.

6. A method of metallizing a surface of a ceramic filter according to claim 1, wherein: the coating method can be one-time coating or multiple-time coating.

7. A method of metallizing a surface of a ceramic filter according to claim 1, wherein: the electroless copper plating and electroless silver plating should also include an activation process prior to the electroless copper plating and electroless silver plating.

8. A method of metallizing a surface of a ceramic filter according to claim 1, wherein: the heat treatment conditions are as follows: nitrogen or argon atmosphere, the temperature is 400-800 ℃, and the time is 0.2-3 h.

Technical Field

The invention relates to the field of mobile communication, in particular to a method for metalizing the surface of a ceramic filter.

Background

With the popularization of 4G networks, the construction of 5G networks, and the rapid development of big data, the frequency spectrum of communication devices in new forms is gradually increasing toward higher frequencies. The penetration force of waves in a high-frequency state is poor, the attenuation is large, and the coverage capability is greatly weakened, so that a large number of small base stations become a new trend in the 5G era. The ceramic dielectric filter has the characteristics of high dielectric constant, high Q value, low loss, small volume, light weight, low cost, good temperature drift resistance and the like. Compared with a small metal cavity filter, the ceramic dielectric filter has lower performance, which is determined by the properties of the material. At present, many filter manufacturers have arranged ceramic dielectric filters for 5G base stations, but since the ceramic process technology is not completely mature, there are not many enterprises capable of mass production.

At present, the production process of the ceramic filter is as follows: firstly, according to the performance requirement of the filter, selecting proper ceramic powder and pressing the ceramic powder into a filter precursor; then, the ceramic blank is subjected to fine machining and then is fired and molded to obtain a ceramic filter blank; and finally, brushing silver paste on the surface of the ceramic filter blank, and then performing secondary sintering to obtain a metal layer with good performance on the ceramic surface. The ceramic filter prepared by the method has the characteristics of high plating reliability and good electromagnetic performance, but the problems of serious silver paste waste and complex sintering process exist in the process. Therefore, the yield of the ceramic filter in the production process is difficult to improve, and the cost is difficult to reduce. In addition, in order to improve the adhesion between the ceramic substrate and the metal layer, silicon dioxide needs to be added into the silver paste to ensure that an intermediate layer is formed in the sintering process to improve the adhesion of the plating layer.

There are many patents that disclose new methods for metallizing ceramic surfaces. In patent CN111641016A, a ceramic substrate is first chemically cleaned, and then a copper and tin metal layer is formed on the surface of the ceramic by using an electroless plating method. The metallization process of the method has low cost and high efficiency, but the formed metal layer has poor bonding force with the ceramic substrate, and the requirement of the communication industry is difficult to meet. In patent CN111393893A, the ceramic surface is polished and ultrasonically cleaned, then a surface metal layer is formed by supersonic spraying in a high temperature environment, and then a metal layer with good performance is further formed on the surface by electroplating. The method adopts a method of matching cold spraying with a high-temperature space and combines a subsequent electroplating process to form a metal layer with good performance on the surface of the ceramic. However, this method requires special equipment, and the ceramic substrate needs to be placed in a high temperature environment of 1200-.

Disclosure of Invention

In order to solve the above problems, it is an object of the present invention to provide a method for metallizing a surface of a ceramic filter. Specifically, the intermediate layer is coated on the surface of the ceramic substrate, then a metal layer is formed on the surface of the ceramic substrate by means of electroless plating and electroplating, and finally the intermediate layer, the ceramic substrate and the metal layer are tightly combined by means of heat treatment.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a method of surface metallization of a ceramic filter, characterized in that the method of surface metallization comprises the steps of:

(1) pretreatment: cleaning the surface of the ceramic filter by a physical or chemical method to remove oil stains on the surface of the filter;

(2) coating the intermediate layer on the surface of the ceramic filter: immersing the cleaned ceramic filter into a solution containing a silicon/titanium compound, and fully immersing to coat a layer of intermediate coating film on the surface of the filter;

(3) metallization of the ceramic surface: carrying out chemical copper plating or chemical silver plating on the ceramic filter coated by the silicon-containing compound to coat a metal layer on the surface of the ceramic filter;

(4) electroplating the surface of the ceramic: carrying out copper electroplating and silver electroplating on the ceramic filter subjected to surface metallization to obtain a good metal layer on the surface of the ceramic filter;

(5) and (3) heat treatment: and placing the electroplated ceramic filter in an inert atmosphere to enable the middle coating layer to react to generate silicon dioxide, and meanwhile, the silicon dioxide is tightly combined with the metal on the surface layer and the matrix ceramic.

Preferably, the physical cleaning method comprises one or more of ultrasonic cleaning, plasma cleaning, high-pressure water jet cleaning or electric pulse cleaning.

Preferably, the chemical cleaning comprises one or more of acid cleaning or alkali cleaning.

Preferably, the silicon-containing compound is silicate, silicate ester and silane coupling agent, and the titanium-containing compound is titanate, titanate and titanium-containing coupling agent.

Preferably, the solution containing silicon/titanium compound is an aqueous solution or an alcoholic solution or a dispersion of one or more of the above compounds.

Preferably, the coating method can be one coating or multiple coatings.

Preferably, the electroless copper plating and electroless silver plating are preceded by an activation process.

Preferably, the heat treatment conditions are as follows: nitrogen or argon atmosphere, the temperature is 400-800 ℃, and the time is 0.2-3 h.

Compared with the prior art, the invention has the following beneficial effects:

1. the scheme of the invention has the characteristics of simple process and high production efficiency, and the obtained product has good performance

2. By carrying out chemical plating and electroplating on the ceramic filter, a metal layer with good performance is conveniently formed on the surface of the ceramic filter, the technological process of metallization of the ceramic filter is greatly shortened, and the production cost is reduced.

3. By forming the intermediate compound layer, the adhesive force of the plating layer is improved, and meanwhile, the electrical property of the filter is not reduced, so that the electrical property of the filter is remarkably improved compared with the prior art.

Drawings

FIG. 1 is a process flow diagram of the present invention.

Detailed Description

The technical solution of the present invention is further explained below with reference to the accompanying drawings, which are believed to be clear to those skilled in the art. Any simple replacement based on the concept of the present invention falls within the scope of protection of the present application.

The invention is briefly described as follows:

firstly, a metal layer with good performance is conveniently formed on the surface of the ceramic filter by carrying out chemical plating and electroplating on the ceramic filter, thereby greatly shortening the metallization process of the ceramic filter and reducing the production cost.

And secondly, by forming the intermediate compound layer, the electric performance of the filter is not reduced while the adhesive force of the plating layer is improved, and the electric performance of the filter is obviously improved compared with the prior art.

Example one

A method for metallizing a surface of a ceramic filter, as shown in fig. 1, comprising the steps of:

(1) pretreatment: the surface of the ceramic filter is cleaned by a physical method to remove oil stains on the surface of the filter so as to ensure the adhesive force of a metal layer on the surface of the ceramic. The physical cleaning method can be selected from one or more of ultrasonic cleaning, plasma cleaning, high-pressure water jet cleaning or electric pulse cleaning.

(2) Coating the intermediate layer on the surface of the ceramic filter: immersing the cleaned ceramic filter into a solution containing a silicon compound, and fully immersing to coat a layer of middle coating film on the surface of the filter; the solution of the silicon-containing compound is an aqueous solution of a silane coupling agent, the mass concentration of the silane coupling agent in the solution is 5-10%, wherein the silane coupling agent can also be replaced by silicate or silicate ester, and the compound is ensured to be uniformly dispersed. The compound can be converted into silicon oxide under the condition of hydrolysis or heating, and can be tightly combined with the base material and the metal layer through thermal diffusion in the subsequent heat treatment process.

(3) Metallization of the ceramic surface: carrying out chemical copper plating on the ceramic filter coated with the silicon-containing compound once to coat a metal layer on the surface of the ceramic filter;

(4) electroplating the surface of the ceramic: electroplating copper on the ceramic filter subjected to surface metallization to obtain a good metal layer on the surface; in order to ensure that the chemical reaction in the chemical plating process occurs on the surface of the ceramic substrate, palladium activation is required to be carried out on the ceramic filter before chemical plating, namely stannous chloride is used for sensitization, palladium is activated and reduced by a palladium chloride solution after hydrolysis, and then chemical copper plating is carried out.

(5) And (3) heat treatment: and (3) placing the electroplated ceramic filter in a nitrogen inert atmosphere at the temperature of 400 ℃ for 0.2h, so that the middle coating layer reacts to generate silicon dioxide, and the silicon dioxide is tightly combined with the metal on the surface layer and the matrix ceramic. And placing the electroplated ceramic filter in a nitrogen inert atmosphere to enable the middle coating layer to react to generate silicon oxide, and meanwhile, the silicon oxide is tightly combined with the metal on the surface layer and the matrix ceramic.

Example two

On the basis of the first embodiment, the process parameters can be modified

A method for metallizing a surface of a ceramic filter, as shown in fig. 1, comprising the steps of:

(1) pretreatment: the surface of the ceramic filter is cleaned by a chemical method to remove oil stains on the surface of the filter so as to ensure the adhesive force of a metal layer on the surface of the ceramic. The chemical cleaning adopts acid cleaning.

(2) Coating the intermediate layer on the surface of the ceramic filter: immersing the cleaned ceramic filter into a solution containing a titanium compound, and fully immersing to coat a layer of middle coating film on the surface of the filter; the solution containing titanium compound is ethanol solution of titanate, the mass concentration of titanate is 10-30%, wherein titanate can be replaced by titanate, titanate and coupling agent containing titanium, and the compound is ensured to be uniformly dispersed. The compounds can be converted into titanium oxide under the condition of hydrolysis or heating, and can be tightly combined with the base material and the metal layer through thermal diffusion in the subsequent heat treatment process.

(3) Metallization of the ceramic surface: carrying out chemical silvering on the ceramic filter coated with the titanium-containing compound once to coat a metal layer on the surface of the ceramic filter;

(4) electroplating the surface of the ceramic: performing silver electroplating on the ceramic filter subjected to surface metallization to obtain a good metal layer on the surface; in order to ensure that the chemical reaction in the electroless plating process occurs on the surface of the ceramic substrate, the ceramic filter needs to be silver-activated before the electroless plating, i.e. silver-containing activator is used.

(5) And (3) heat treatment: and (3) placing the electroplated ceramic filter in an inert atmosphere of argon at the temperature of 800 ℃ for 3 hours to enable the middle coating layer to react to generate titanium dioxide, and meanwhile, the titanium dioxide is tightly combined with the metal on the surface layer and the matrix ceramic. The electroplated ceramic filter is placed in an argon inert atmosphere, so that the intermediate coating layer reacts to generate titanium oxide, and the titanium oxide is tightly combined with the metal on the surface layer and the matrix ceramic.

EXAMPLE III

On the basis of the first embodiment, the process parameters can be modified

A method for metallizing a surface of a ceramic filter, as shown in fig. 1, comprising the steps of:

(1) pretreatment: the surface of the ceramic filter is cleaned by a chemical method to remove oil stains on the surface of the filter so as to ensure the adhesive force of a metal layer on the surface of the ceramic. The chemical cleaning adopts alkaline cleaning.

(2) Coating the intermediate layer on the surface of the ceramic filter: immersing the cleaned ceramic filter into a solution containing a silicon/titanium compound, and fully immersing to coat a layer of intermediate coating film on the surface of the filter;

the silicon/titanium-containing coupling agent is a mixed solution of silicate ester and a titanium-containing coupling agent, and a dispersion liquid of a methanol solution, wherein the mass concentration of the silicate ester is 5-10%, and the mass concentration of the titanium-containing coupling agent is 8-20%, the silicate ester can be replaced by silicate, silicate ester or a silane coupling agent, the titanium-containing coupling agent can be replaced by titanate, titanate or the titanium-containing coupling agent, and the uniform dispersion of the compound is ensured. The compound can be converted into silicon oxide and titanium oxide under the condition of hydrolysis or heating, and can be tightly combined with the base material and the metal layer through thermal diffusion in the subsequent heat treatment process.

(3) Metallization of the ceramic surface: carrying out chemical copper plating on the ceramic filter coated with the silicon/titanium-containing compound for multiple times to coat a metal layer on the surface of the ceramic filter;

(4) electroplating the surface of the ceramic: electroplating copper on the ceramic filter subjected to surface metallization to obtain a good metal layer on the surface; in order to ensure that the chemical reaction in the chemical plating process occurs on the surface of the ceramic substrate, the ceramic filter needs to be activated by palladium before chemical plating, and a colloid palladium process is adopted.

(5) And (3) heat treatment: and (3) placing the electroplated ceramic filter in a nitrogen inert atmosphere at the temperature of 600 ℃ for 2 hours to enable the middle coating layer to react to generate silicon dioxide, and meanwhile, the silicon dioxide is tightly combined with the metal on the surface layer and the matrix ceramic. And placing the electroplated ceramic filter in an inert atmosphere to enable the middle coating layer to react to generate silicon oxide or titanium oxide, and meanwhile, the middle coating layer is tightly combined with the metal on the surface layer and the base ceramic.