JPS61146778A - Metallization of ceramics - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a simple method for metallizing ceramics.

11th and 1st base In general, ceramics have excellent heat resistance, abrasion resistance, insulation, etc., but are brittle and weak against impact, so when used as a structural material, they are often used as a bonded body with metal. When joining metal and ceramics, it is first necessary to metalize the surface of the ceramics. Also,
When ceramics are used as conductive materials, the surfaces of the ceramics are metallized.

Known methods for metallizing ceramics include the Telefunken method, active metal method, hydride compound method, oxide solder method, and silver carbonate method, but methods other than the Telefunken method have complicated processes. In addition, the adhesive strength, thermal shock resistance, chemical resistance, etc. of the metallized layer may not be sufficient, so the Telefunken method is generally used at present. In the Telefunken method, the ceramic surface is coated with molybdenum-manganese, baked at a high temperature of 1400 to 1700°C in a non-oxidizing atmosphere, plated with metal, and then coated again in a non-oxidizing atmosphere to stabilize the coating. This method remetallizes the metal by heating it, and then brazes the metal if necessary. However, this method has the major disadvantage that the working process is long and complicated, and also has the disadvantage that the heating temperature is high.

As a result of intensive research to develop a ceramic metallization method that eliminates the above-mentioned drawbacks, the present inventor has discovered that at least one of copper carbonate, sulfuric acid steel, copper sulfide, oxidized steel, and chloride steel and S
When a mixture of SiO2 or kaolin is used as a coating layer, it can be baked at a relatively low temperature in an oxidizing atmosphere such as air, and then the baking layer can be metalized very easily by reducing the layer. It was discovered that the uniformity of the metallized layer, especially the surface smoothness and gloss, was improved by the combined use, and that the obtained metallized layer had excellent conductivity and high adhesive strength.Based on these findings, A separate patent application was filed (Japanese Patent Application 1983-1983)
No. 721 and Japanese Patent Application No. 131575/1982).

Therefore, in subsequent research, the present inventor found that the adhesive strength and chemical resistance of the metallized layer were significantly improved by further adding at least one of palladium, palladium oxide, and platinum chloride to the mixture described in 6E. They discovered this and completed the present invention.

The present invention provides a mixture comprising at least one of copper carbonate, copper sulfate, copper sulfide, oxidized steel and chlorinated steel, SiO2 or (and) kaolin, and at least one of palladium, palladium oxide and platinum chloride. , relates to a ceramic metallization method characterized in that the layer is coated on a ceramic surface, heated and baked at 900 to 1300° C. in an oxidizing atmosphere, and then the layer is subjected to a reduction treatment during baking.

In the present invention, SiO2 or (and)
By using kaolin in combination, it is possible to prevent uneven baking and improve the uniformity of the metallized layer, especially the surface smoothness and gloss. By using one type in combination, the adhesive strength and chemical resistance of the metallized layer are significantly improved.

Carbonated steel, sulfuric acid steel, copper sulfide, oxidized steel, and chlorinated steel used as the coating layer in the present invention are all usually in powder form. The particle size of the powder is not particularly limited, but it is usually about 100 μm or less, preferably about 50 μm JX or less.

Examples of palladium oxide used as the coating layer in the present invention include Pd01PdtO3, PdO2, etc., and examples of platinum chloride include PtC(I2, PtCQi, etc.), and any of these can be used.

Further, 5i02, kaolin, palladium, palladium oxide and platinum chloride are also usually used in powder form. The particle size is the same as above.

The proportion of each component used is approximately 80-30% by weight of at least one of copper carbonate, copper sulfate, copper sulfide, oxidized steel, and chloride steel, and 5-30% by weight of 5fO2 or (and) kaolin. The content of at least one of palladium, palladium oxide, and platinum chloride is approximately 10 to 60% by weight, preferably 20 to 50% by weight.

If 5i02 or (and) kaolin is not mixed in an amount of 5% by weight, the surface smoothness and gloss of the metallized layer may become insufficient, and if it exceeds 3011ff1%, the conductivity of the metallized layer tends to decrease. I don't like it because there is.

Furthermore, it is not preferable if at least one of palladium, palladium oxide, and platinum chloride is less than 10% by weight or exceeds 60% by weight, since the adhesive strength of the metallized layer tends to be insufficiently improved. .

In the present invention, copper carbonate, iil[l'#i, copper sulfide, at least one of oxidized steel and chloride steel, 5lo2 or (
and) Kaolin and a mixture of at least one of palladium, palladium oxide, and platinum chloride may be used in powder form, or a suitable binder and its solvent, such as printing ink such as screen oil, balsam, etc. may be used as appropriate. It may also be used in the form of a paste.

A powder or paste mixture is sprinkled or coated on the ceramic surface that requires metallization. The amount of coating is not particularly limited, and is appropriately determined depending on the desired thickness of the metallized layer. Next, the ceramic coated above is heated in an oxidizing atmosphere to bake the coating layer. It is not necessary to use a special oxidizing atmosphere, and it is sufficient to use air, a mixture of air and nitrogen, or the like. The heating conditions vary depending on the shape and size of the ceramic, the type of coating layer used, the amount of coating, etc., but are usually heated at a temperature of 900 to 1300° C. for about 5 to 60 minutes. By this heating, copper carbonate, copper sulfate, copper sulfide, or steel chloride is oxidized to copper oxide, palladium is oxidized to palladium oxide, platinum chloride is oxidized to platinum oxide, and copper oxide and palladium oxide or (and ) A coating mainly composed of platinum oxide adheres to ceramics. On this occasion,
The adhesive strength of the metallized layer obtained is increased by partially penetrating the oxidized steel melt into the ceramic. or,
The adhesive strength and chemical resistance of the metallized layer obtained by the combined use of at least one of palladium, palladium oxide, and platinum chloride are significantly improved. Furthermore,
By using 8102 and/or kaolin, the uniformity, surface texture and gloss of the metallized layer are significantly enhanced. If the heating temperature is lower than 900°C, the above-mentioned permeation will not occur and the adhesive strength will be insufficient, and if it is higher than 1300°C, the viscosity of the coating layer will decrease and may flow out, which is not preferable.

Next, baking reduces the layered ceramics as described above. The reduction method is not particularly limited, and any method may be used as long as oxidized steel, palladium oxide, and platinum oxide are reduced to metal copper, palladium, and platinum, respectively, such as a reducing atmosphere such as a hydrogen atmosphere or a -carbon oxide atmosphere. Examples include heating in a vacuum, immersion in alcohols such as ethanol, methanol, propatool, etc., reducing solvents such as benzine and formalin, and immersion in an aqueous solution of dimethylamineporane. The temperature when heating in a reducing atmosphere is preferably lower than the baking temperature in order to prevent layer decomposition, deterioration, etc., and is usually 200 to 90
The temperature is about 0°C, and the time is usually about 5 to 60 minutes. In addition, in the case of immersion in a reducing solvent, the ceramic is usually heated to about 200 to 500°C, preferably around 300°C, and then soaked in the reducing solvent for 10 to 60 seconds. ! ! ! Just soak it once. Further, in the case of immersion in a dimethylamine borane aqueous solution, the ceramic may be heated to about 40 to 60° C. and then immersed in the aqueous solution for about 10 to 60 seconds.

Through the above reduction treatment, copper has extremely high conductivity.
A palladium or/and platinum metallization layer is formed on the ceramic surface.

If necessary, various metals can be easily joined to the thus metallized ceramics by conventional methods such as brazing.

Ceramics that can be metalized according to the present invention include:
Examples include oxide ceramics such as silicon nitride, silicon carbide, and aluminum nitride, and oxide ceramics such as alumina, zirconia, mullite, beryllia, magnesia, and cordierite, but are not particularly limited. can.

According to the present invention, a metallized layer can be formed on the ceramic surface by an extremely simple operation of baking at a lower temperature and then performing a reduction treatment compared to the conventional method, and the obtained metallized layer has excellent conductivity and adhesive strength. It has extremely high chemical resistance, and the metallized layer has excellent uniformity, especially surface smoothness and gloss, so it has a high commercial value.

Ceramics metallized according to the present invention.

Since it has the above-mentioned performance, it can be suitably used for ceramic packages, electronic parts such as printed wiring of IC boards, wear-resistant parts using ceramics, heat-resistant parts, etc.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Copper oxide powder (particle size 5 μm) 4511%, palladium powder (particle size 5 μm) 45% by weight and 8102 powder (particle size 5 μm)
) 101i (% by weight) mixed, 10 parts by weight of balsam is mixed to make a paste, and this is mixed into a paste of flat square silicon nitride (SI3N), SiO, silicon carbide (SiC), and alumina. Alternatively, 0.10/C2 was applied to the surface of a zirconia sintered body. Next, the film was baked in air at 1100° C. for 20 minutes using an electric furnace to form a coating layer. The calcined product was then heated to 50° C. in a dryer and then immersed in a 5% aqueous solution of dimethylamine borane. As a result, the baking layer is reduced and the metallic copper
A metallized layer of palladium was formed. Table 1 below shows the electrical resistance values measured at a voltage of i ooov before and after reduction. It was found that the metallized layer after reduction had extremely excellent electrical conductivity.

Each of the ceramics having the metallized layer obtained in this manner and a copper piece were soldered using silver solder, and the adhesive strength of the metallized layer was measured using a tensile tester with a scale of 12 tons and a loading rate of 511/Win. It was found that the bond was extremely strong.

The results are also listed in Table 1 below.

Table 1 In order to check the chemical resistance of the metallized layer of each ceramic obtained above, it was heated at 70°C in a 48% KOH7JC solution.
A 72-hour immersion test was conducted, but no changes in discoloration, conductivity, adhesive strength, etc. were observed.

Furthermore, the obtained metallized layer had excellent uniformity, particularly surface smoothness and gloss, and had high commercial value.

Example 2 The results shown in Table 2 below were obtained in the same manner as in Example 1, except that palladium oxide (PdO) powder (particle size: 5 μm) was used instead of palladium powder.

Table 2 It is clear from Table 2 that the metallized layer has extremely good conductivity and extremely high adhesive strength.

In order to investigate the chemical resistance of the metallized layer of each ceramic obtained above,
A time immersion test was conducted, but no change in color, conductivity, adhesive strength, etc. was observed.

Furthermore, the obtained metallized layer had excellent uniformity, particularly surface smoothness and gloss, and had high commercial value.

Example 3 The results shown in Table 3 below were obtained in the same manner as in Example 1, except that platinum chloride (PtCI22) (particle size 5 μm) was used in place of palladium powder.

Table 3 It is clear from Table 3 that the metallized layer has extremely good conductivity and extremely high adhesive strength.

In order to investigate the chemical resistance of the metallized layer of each ceramic obtained above,
A time immersion test was performed, but no change in color, conductivity, adhesive strength, etc. was observed.

Furthermore, the obtained metallized layer had excellent uniformity, particularly surface smoothness and gloss, and had high commercial value.

(that's all)

Claims (1)

[Claims] (1) A mixture consisting of at least one of copper carbonate, sulfuric acid steel, sulfide steel, oxidized steel, and chloride steel, SiO2 or (and) kaolin, and at least one of palladium, palladium oxide, and platinum chloride is coated on the ceramic surface. A method for metallizing ceramics, which comprises heating and baking at 900 to 1300° C. in an oxidizing atmosphere, and then subjecting the baked layer to reduction treatment.