JPS61215280A - Ceramic metallization - 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] ll standing leg 11 The present invention relates to a method for metallizing ceramics.

Conventional techniques and part 1 Ceramics generally have excellent heat resistance, abrasion resistance, insulation, etc., but because they have poor Wi-impact resistance, they are often used as structural materials in conjunction with metals. . When joining ceramics and metal, it is necessary to metalize the surface of the ceramic in advance, and when using ceramic as a conductive material, the surface must also be metalized.

Ceramics metallization methods include the Telefunken method,
The active metal method, hydride compound method, oxide solder method, silver carbonate method, etc. are known, but methods other than the Telefunken method are
is hardly used.

This is because not only the process is complicated, but also the adhesive strength, thermal shock resistance, chemical resistance, etc. of the obtained metallized layer are often insufficient. In the currently commonly used Telefunken method, the surface of ceramics is coated with molybdenum-manganese, and the
After baking at a high temperature of about 1700° C., metal plating is performed, and then heating is performed again in a non-oxidizing atmosphere to form a stabilized metallized layer.

However, this method also requires a complicated multi-step process and has the drawbacks of high heating humidity.

The present inventors conducted research to solve the above-mentioned drawbacks of the prior art, and found that at least one of copper carbonate, copper sulfate, copper sulfide, copper oxide, and copper chloride, and at least one of 8102 and kaolin! When using as a coating material for ceramics a mixture with tin oxide, or a mixture with tin oxide added to the mixture, or a mixture with at least one of palladium, palladium oxide, and platinum chloride added to the mixture, the comparative We discovered that a metallized layer with excellent physical properties such as adhesive strength, thermal shock resistance, chemical resistance, and electrical conductivity could be formed on ceramics through a simple process at relatively low temperatures.Based on these findings, we developed the invention. It is already in the process of applying for a patent (patent application filed in 1982-
No. 83721, patent application No. 131575, patent application No. 1983
No. 9-207685, patent application No. 1983-269900, etc.)
.

Means for Solving the Problems As a result of further research into metallization methods for ceramics, the present inventor discovered that metallization methods can be made from copper compounds such as copper carbonate, at least one of 5fO2 and kaolin, and at least one of rare earth elements and their compounds. It has been found that when the mixture is used as a coating material for ceramics, a metallized layer with excellent various physical properties can be obtained by simple operation at low temperatures. That is, the present invention provides (1) copper carbonate, copper sulfate,
at least one of copper sulfide, oxidized steel and copper chloride, (ii
) A mixture consisting of at least one of Si, 02 and kaolin, and (iii) at least one of rare earth elements and their compounds is applied to the ceramic surface and baked at 900 to 1300°C in an oxidizing atmosphere. The present invention relates to a ceramic metallization method characterized by subjecting a layer to a reduction treatment.

Copper carbonate, copper sulfate, used as a coating material in the present invention,
Copper sulfide, copper oxide and copper chloride are all usually used in powder form. The particle size of the powder is not particularly limited, but is usually 1
It is preferably 50 μm or less, more preferably 50 μm or less.

5i02 and kaolin are also preferably used as powders, the particle size of which is similar to that of the above compounds.

The rare earth elements used as other components of the coating material in the present invention include scandium (atomic number 21), yttrium (atomic number 39), and atomic number 1 ranging from atomic number 57 to 71.
There are 5 elements, 17 elements in total.

These are classified into cerium group rare earth elements consisting of La, Ce, Pr, Nd, pm, and 3m, and yttrium group rare earth elements consisting of other elements, but cerium group rare earth elements form a metallized layer. It is more preferable because it greatly improves physical properties such as adhesive strength. Rare earth elements include carbonates, oxalates, phosphorus M salts, nitrates, and sulfur FII
It may be used in the form of compounds such as salts, oxides, hydroxides, peroxides, halides, and sulfides. The rare earth elements and their compounds are preferably used in the form of powder,
The particle size is also the same as that of the copper compound. Incidentally, the chemical properties of rare earth elements are very similar, and in the present invention, each of them has almost the same effect. Therefore,
Mixed minerals such as monazite can be used as the rare earth element source.

The proportion of each component used in the coating material of the present invention is at least one of copper carbonate, copper sulfate, copper sulfide, oxidized steel, and copper chloride.
~30% by weight, at least one of 5f02 and kaolin, approximately 5 to 30% by weight (preferably 7 to 20% by weight)
, at least one rare earth element and its compound 10-6
It is appropriate to set it to about 2% by weight (preferably 20 to 501ffi%) o If 51ffi% of SIO2 and/or kaolin is not swirled, the smoothness and gloss of the surface of the metallized layer may be insufficient. On the other hand, 30 fold f
If it exceeds fi%, the conductivity of the metallized layer tends to decrease. If the content of at least one of the rare earth elements and their compounds is less than 101% or more than 60%, the adhesive strength of the metallized layer will not be sufficiently improved, which is not preferable.

The method of the present invention is usually carried out as follows.

The coating material having the above composition is sprinkled or applied in powder form or in the form of a paste onto the ceramic surface on which the metallized layer is to be formed. In the case of making a paste, an appropriate amount of a binder and its solvent, such as balsam and screen oil, may be added to the powder mixture. The amount applied to ceramics is not particularly limited, and is appropriately determined depending on the desired thickness of the metallized layer. Next, the ceramic coated with the coating material is heated in an oxidizing atmosphere to bake the coating layer. The oxidizing atmosphere is not particularly limited, but
There is no need to use anything special; air, a mixture of air and nitrogen, etc. may be used.

The heating conditions may vary depending on the shape and dimensions of the ceramic, the composition of the coating material, the applied G, etc., but are usually 900 to 1300
Heat at about ℃ for about 5 to 60 minutes. In this case, copper compounds other than copper oxide become copper oxide, rare earth elements and/or their compounds become oxides, and a coating mainly composed of copper oxide and rare earth element oxides and containing 5i02 and/or kaolin powder is formed. Adheres to ceramics. At this time, a portion of the copper oxide melt permeates into the ceramics, thereby improving the adhesive strength of the resulting metallized layer. In addition, the combined use of rare earth elements and/or their compounds not only significantly improves the adhesive strength of the metallized layer, but also greatly improves chemical resistance. Furthermore, the use of 5fO2 and/or kaolin significantly improves the uniformity, surface smoothness and gloss of the metallized layer. If the heating temperature is less than 900°C, the penetration of the copper oxide melt into the ceramics will be insufficient, resulting in insufficient adhesive strength, while if it exceeds 1300°C, the viscosity of the rjIB will decrease. , there is a risk of leakage.

Baking then reduces the layered ceramics as described above. The reduction method is not particularly limited as long as the copper oxide and rare earth element compound is reduced to copper and rare earth element. Typical reduction treatment methods include heating in a reducing atmosphere such as a hydrogen atmosphere or -a carbon atmosphere, immersion in alcohols such as ethanol, methanol, and propatool, and reducing solvents such as petroleum benzene and formaldehyde. Examples include immersion in a dimethylamine borane aqueous solution, and immersion in a dimethylamine borane aqueous solution. 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 may be heated to usually about 200 to 500°C, preferably about 300°C, and then immersed in the reducing solvent for about 10 to 60 seconds. 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 10 to 60 seconds.

By the above reduction treatment, a metallized layer made of copper and a rare earth element having extremely excellent conductivity is formed on the surface of the ceramic.

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

Ceramics that can be metallized according to the present invention are not particularly limited, and include non-oxide ceramics such as silicon nitride, sialon, silicon carbide, and aluminum nitride, and oxide ceramics such as alumina, zirconia, mullite, beryllia, magnesia, and cordierite. Ceramics can be mentioned.

Effects of the Invention According to the present invention, a metallized layer can be formed on a ceramic surface by an extremely simple operation of performing baking and then reduction treatment at lower humidity than in conventional methods. The obtained metallization Q is
It has high commercial value because it has excellent conductivity, extremely high adhesive strength and chemical resistance, and the uniformity of the metallized layer, especially excellent surface smoothness and gloss.

Since the ceramics metallized according to the present invention 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.

Friend - 1 Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 5f0210 parts by weight, N for 70 parts by weight of copper oxide powder
620,320 parts by weight and 10 parts by weight of balsam were mixed to form a paste, and this was applied at 0.1 g/C12 onto the surface of each of flat square sintered bodies of silicon nitride, sialon, silicon carbide, alumina, and zirconia. Next, each sintered body was fired in air at 1100° C. for 30 minutes using an electric furnace to form a coating layer. The calcined material was then heated at 60 DEG C. during the drying period and then immersed in a 5% solution of dimethylamine borane. As a result, the baking layer was reduced and a metallized layer of metallic steel was formed. Table 1 below shows the electrical resistance values before and after reduction (N pressure 1000V)
shows. It is clear that the metallized layer after reduction has extremely good electrical conductivity.

Each of the ceramics having the metallized layer thus obtained and a copper piece were brazed together 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/sin. As shown in Table 1, it was found that both were extremely strongly bonded.

(that's all)

Claims (1)

[Claims] [1] (i) at least one of copper carbonate, copper sulfate, copper sulfide, copper oxide and copper chloride, (ii) at least one of SiO_2 and kaolin, and (iii) at least one of rare earth elements and their compounds A method for metallizing ceramics, which comprises applying a mixture of the following to the surface of ceramics, baking the mixture at 900 to 1300°C in an oxidizing atmosphere, and then subjecting the baked layer to reduction treatment.