JPS6358796B2 - - Google Patents

Description

[Detailed description of the invention] (Technical field to which the invention pertains) The present invention relates to a method for roughening the surface of ceramic bodies.

(Prior art and its problems) Conventional methods for roughening the surface of ceramic bodies include heating hydrofluoric acid, concentrated phosphoric acid, etc. and immersing the ceramic body in the heated solution, or immersing the ceramic body in a heated solution of caustic soda. There is a method of soaking the ceramic body. However, the above-mentioned acid roughening method mainly selectively etches and roughens only the glass phase between the crystal grains of the ceramic, and cannot homogeneously roughen the entire ceramic. Roughening using a caustic soda melt can roughen the ceramic by etching both the crystal grains and the glass phase. However, when it is desired to shallowly roughen only the surface layer of the ceramic body, it is possible to roughen the ceramic by etching both the crystal grains and the glass phase. The etching time is short, about several tens of seconds, and workability is poor. Difficult to control details. Furthermore, since the temperature of the melt used for roughening is as high as 400°C or higher, there is a drawback that if the ceramic body is directly immersed in the melt, cracks or cracks will occur in the ceramic body due to thermal shock.

In order to overcome the above-mentioned drawbacks, there is a method in which a ceramic body is immersed in an aqueous alkaline solution to adhere an alkali to the surface, dried, and then heated to melt the alkali and roughen the ceramic body by etching it. However, with this method, dry alkali tends to aggregate, which tends to form lumps on the surface of the ceramic body.As a result, the alkali aggregates unevenly and remains, and there are problems with the wettability of the aqueous alkali solution to the ceramic body. It has been found that there is a drawback that uniform roughening cannot be achieved on the surface of the ceramic body due to an insufficient absolute amount of alkali on the surface of the ceramic body or a difference in the absolute amount of alkali deposited between the edges and the center.

(Object of the Invention) The object of the present invention is to provide a method for roughening the surface of a ceramic body without the above-mentioned drawbacks.

(Means for Solving the Problems) The present inventors conducted various studies on the above-mentioned drawbacks, and found that a ceramic body was interposed between the meshes, immersed in an alkaline aqueous solution to adhere an alkali, and then heated to a temperature higher than the melting point of the alkali. When heat treated at high temperatures, it was confirmed that the surface of the ceramic body could be uniformly roughened.

(Structure of the Invention) The present invention relates to a method for roughening the surface of a ceramic body, in which the ceramic body is interposed between meshes, immersed in an aqueous alkali solution to adhere an alkali, and then heat-treated at a temperature equal to or higher than the melting point of the alkali.

In addition, in the present invention, a mesh with a large mesh is suitable for holding the alkaline solution homogeneously because the wire diameter is smaller and the wire spacing at the opening can be narrower, but even a mesh with a small mesh can hold the alkaline solution uniformly. If an inorganic or organic fine powder that wets well with the solvent is added to the solution, the alkaline solution can be held by a meniscus between the fine powder and the fine powder. Therefore, in the present invention, there is no particular restriction on the mesh size.

There are no particular restrictions on the material of the net, but it is preferable to use metal wires such as stainless steel or nickel, which can be reused many times in terms of cost.

The concentration of the alkaline solution, the heat treatment temperature, and the heat treatment time are determined arbitrarily as they vary depending on the desired roughening state, but the heat treatment temperature may be higher than the melting point of the alkali used. This is necessary, and at temperatures below the melting point of the alkali, the alkali will not melt and will not be able to etch and roughen the ceramic body.

As the alkaline aqueous solution, an aqueous solution of caustic soda, potassium hydroxide, sodium orthosilicate, etc. is used.

In the present invention, in addition to the above steps, after the heat treatment, the surface may be neutralized by immersion in an aqueous hydrochloric acid solution if necessary.

(Example) The present invention will be explained below with reference to Examples.

After arranging #200 (200 mesh) stainless steel mesh on the top and bottom surfaces of a ceramic substrate with an alumina content of 96% by weight, dimensions of 20 x 20 mm, and thickness of 1 mm, the ceramic substrate was firmly fixed, and the concentration of this was 50%. The sample was immersed in an aqueous solution of caustic soda for 5 minutes, and then dried with hot air at 90°C for 1 hour. Then 600℃ at a heating rate of 20℃/min.
After heating to 600°C for 20 minutes, the mixture was naturally cooled to room temperature. The ceramic substrate was washed with running water for 10 minutes, then immersed in a 10% hydrochloric acid aqueous solution for 3 minutes, and then rinsed with running water for 10 minutes in the same manner as above, the stainless steel screen was removed, and the ceramic substrate was heated at 90°C for 1 hour. Dry with hot air. After drying, the ceramic substrate was observed with a SEM, and it was found that the entire surface of the ceramic substrate was uniformly roughened.

(Effects of the Invention) In the present invention, a ceramic body is interposed between meshes, immersed in an alkaline aqueous solution to adhere an alkali, and then heat treated at a temperature higher than the melting point of the alkali, so that the surface of the ceramic body can be uniformly roughened. can do.

Claims (1)

[Claims] 1. A method for roughening the surface of a ceramic body, which comprises interposing the ceramic body between meshes, immersing the ceramic body in an alkaline aqueous solution to adhere an alkali, and then heat-treating the ceramic body at a temperature equal to or higher than the melting point of the alkali.