JPS6354429B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coating method for uniformly and appropriately depositing a coating material onto the surface of an object to be coated.

For example, when forming electrodes on the surface of dielectric ceramic, a paste obtained by mixing silver, glass frit, solvent, etc. is screen printed, sprayed, etc.
It can be applied to the porcelain surface by coating or other methods, then heat-treated and baked, or the dielectric porcelain can be immersed in the above-mentioned paste, then pulled up and baked, or a conductive solution such as tin chloride can be heated. There is a method in which a conductive film of tin oxide is formed by condensing the evaporated gas on the surface of the heated dielectric ceramic while evaporating the gas.

However, all of the above-mentioned methods have the disadvantage that the electrical characteristics of the obtained capacitor are unstable because the thickness of the electrode material is not constant.

This invention has been made in view of the above-mentioned conventional drawbacks, and provides a method for uniformly and appropriately depositing a coating material such as a conductive paste on an object to be coated such as dielectric porcelain. consists of a coating material, an object to be coated, and an adhesion promoter for uniformly applying the coating material to the object,
By mixing these materials, the coating material is uniformly adhered to the surface of the object to be coated via the surface of the adhesion promoter.

This invention will be described in detail below with reference to Examples.

Example 1 50 alumina balls with a diameter of 6 mm and 100 g of paste mixed with PbO and organic varnish (solid content of PbO: 50
g), and an iron ball with a diameter of 1.5 mm as an adhesion promoter.
We prepared 500 pieces each.

Next, the alumina balls, paste, and iron balls were placed together in a pot mill and mixed for about an hour while being maintained at a temperature of 20 to 100°C to adhere the PbO paste to the surface of the alumina balls. Furthermore, while attracting the iron balls with a magnet, they separated the alumina balls from the iron balls by taking advantage of their different shapes, and then heat-treated them at 50 to 200°C for about 30 minutes to diffuse the PbO paste onto the surfaces of the alumina balls.

The surface of each of the obtained samples was observed using a reflection microscope, and the uniformity of the coating material was visually confirmed. No unevenness was observed on the coating surface, indicating good results.

Further, when the amount of adhesion was measured and the distribution of the amount of adhesion was investigated, the standard deviation value was 0.015 g. In addition,
The amount of PbO paste attached to the alumina sphere is 0.85g
The variation was determined by taking the average amount of adhesion as the average amount.

As a comparative example, an alumina sphere was prepared in the same manner as in the above example, and it was dipped in a paste mixed with PbO and organic varnish, and then pulled out to check the uniformity and amount of coating material on the surface of the alumina sphere. When similarly measured, unevenness was observed on the surface, and when the distribution of the amount of adhesion was examined, the standard deviation value was 0.4 g. The average amount of adhesion at this time is
It was 0.8g.

According to this example, the PbO paste was uniformly adhered to the surface of the alumina sphere, and the variation in the amount of adhesion was small.

Example 2 50 alumina disks with a diameter of 5 mm and a thickness of 0.2 mm,
100g paste mixed with Bi ₂ O ₃ and organic varnish
(Solid content of Bi ₂ O ₃ 50 g) and 500 polyfluorinated ethylene resin balls with a diameter of 1.0 mm were prepared as adhesion promoters. Next, the alumina disk, paste, and polyfluorinated ethylene resin balls were placed together in a pot mill and mixed for about 1 hour while being maintained at a temperature of 20 to 100°C to coat the surface of the alumina disk with Bi ₂ O ₃ paste. Attached. After further heat treatment at 50 to 200℃ for 30 minutes to diffuse the Bi ₂ O ₃ paste on the surface of the alumina disk, the alumina disk and the polyfluorinated ethylene resin sphere are subjected to vibration, for example, using the density difference. However, the two were separated. Furthermore, the density of the alumina disk is
3.97g/cm ³ , the density of polyfluorinated ethylene resin is
It is 2.38g/ ^cm3 .

Regarding the obtained sample, the uniformity and amount of Bi ₂ O ₃ paste adhered to the surface of the alumina disk were measured in the same manner as in Example 1, and no unevenness was observed on the surface. When the distribution was examined, the standard deviation value was 0.008 g. Note that the average amount of Bi ₂ O ₃ paste adhered to the alumina disk was 0.5 g.

As a comparative example, similar to this Example 2, a diameter of 5
Prepare 50 alumina disks with a thickness of 0.2 mm and heat the Bi ₂ O ₃ powder at 900℃ to evaporate the Bi ₂ O ₃ , place the alumina disks in this evaporated gas, and When we measured the uniformity and amount of the adherent material made of Bi ₂ O ₃ attached to the surface of the alumina disk, we found that there were some areas where no adhered material had adhered, and when we examined the distribution of the amount of adhered material, we found that the standard deviation was The value was 0.06g. The average amount of Bi ₂ O ₃ deposited on the alumina disk was 0.1 g.

In Example 1 described above, an iron ball was used as an object that is magnetically attracted as an adhesion promoter, but other objects that are magnetically attracted include metals such as nickel and cobalt, ceramics such as ferrite, or It may be a composite material such as magnetic rubber, and in short, any material that is magnetically attracted may be used. Further, the shape is not limited to a sphere, but may be a polyhedron such as a tetrahedron or a hexahedron. Preferably, the object to be coated and the adhesion promoter may be shaped to form point or line contact so that they do not come into close contact with each other using the coating material as a medium. Furthermore, the size is determined by considering the size of the object to be coated, for example, in the above example, the size of the alumina spheres and alumina disks. Any object that can be covered by the body and that can evenly contact the surface of the object to be coated may be used. In addition, if the adhesion promoter is made of a material that is magnetically attracted, synthetic resin,
The surface may be treated with rubber, glass, etc. to the extent that magnetism is permeable.

In addition, in Example 2 described above, the density difference between the adhesion promoter and the alumina disk that is the object to be coated is
Although tetrafluoroethylene resin with a density of 0.1 g/cm ³ or more was used, other materials such as nylon, rubber, lead, etc. are not particularly limited as long as the difference in density between the material and the material to be coated is 0.1 g/cm ³ or more. Of course, like the iron ball used in Example 1, it is magnetically attracted, and the density difference is 0.1g/
If a material with a size of cm ³ or more is used, it can be separated from the object to be coated using magnetism or density difference. The reason why we set the density difference to be 0.1 g/cm ³ or more is because if this value is not exceeded, it will be difficult to separate it from the object to be coated.
This is because separation using density differences is not possible.

Furthermore, in separating the object to be coated and the adhesion promoter, it is of course possible to take advantage of the difference in shape, size, etc. between the two, for example, by using a sieve.

Furthermore, although alumina, which is an insulator that is not attracted to magnetism, has been described as a material to be coated, other materials such as dielectric ceramics, piezoelectric ceramics, and semiconductor ceramics can also be applied. For example, in grain boundary insulated semiconductor porcelain capacitors, the grain boundaries of semiconductor porcelain
When forming an insulating layer made of metal oxides such as PbO, Bi ₂ O ₃ , CuO, etc., these pastes are attached to the porcelain surface and then heated to diffuse into the porcelain. Evenly on the surface,
In addition, it is possible to deposit a suitable amount of it, and a grain boundary insulated semiconductor ceramic capacitor with small variations in characteristics can be obtained. In addition to the above, it goes without saying that it can also be applied to objects that can be separated from magnetically attracted objects, such as synthetic resins, rubber, glass, etc., when uniformly coated on their surfaces. Furthermore, when forming a circuit pattern according to the purpose on the board,
Pattern formation is also possible by applying this method via a mask with the required circuit pattern.

The coating material may be any other general electrical material such as a conductive material, a resistive material, an insulating material, etc., and these may be used in the form of a paste.

Furthermore, in order to uniformly apply and diffuse the coating material onto the object to be coated, heat treatment was carried out in Examples 1 and 2 described above, but if ultrasonic vibration is applied or the coating material comes into contact with moisture, it will deliquesce. If it can be diffused, it may be treated in a humid environment.

As described above, according to the method of the present invention, since the coating material is applied to the object to be coated in multi-point contact using the adhesion promoter as a medium, the required amount of the coating material can be evenly adhered to the object to be coated. It has great utility as it allows a large amount of coating material to be coated using a simple method and can also be applied to objects with complex shapes.

Claims (1)

[Claims] 1. Consists of a coating material, a plurality of objects to be coated, and a plurality of adhesion promoters for uniformly applying the coating material to the objects to be coated, and by mixing these,
A method for applying a coating material, which comprises uniformly adhering the coating material to the surface of an object to be coated via the surface of an adhesion promoter. 2. The method for applying a coating material according to claim 1, wherein the adhesion promoter has a shape that makes point or line contact with the object to be coated. 3. The method for applying a coating material according to claim 1 or 2, wherein the adhesion promoter is composed of an object that is magnetically attracted. 4 The density difference between the adhesion promoter and the object to be coated is 0.1 g/
A method for applying a coating material according to claim 1 or 2, wherein the coating material has a density of cm ³ or more. 5 The adhesion promoter is composed of an object that is magnetically attracted and has a density difference of 0.1 with the object to be coated.
A method for applying a coating material according to claim 1 or 2, wherein the coating material has a density of g/cm ³ or more.