JPS6146530B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a silver-oxide contact material.

It is generally known that in order to improve the welding resistance of electrical contact materials made of silver and oxides, the oxides must be uniformly and finely dispersed in the silver substrate.

By the way, in the conventional production of silver-oxide, in which silver and oxide powder are simply mixed and sintered, even if fine powder with a particle size of 44μ (325 mesh) or less is used, it is difficult to mix the powder. Because it is difficult to sufficiently loosen the silver and oxide powder and mix the oxide powder uniformly and finely, after sintering, the oxide powder is dispersed non-uniformly as large oxide particles, making it difficult to achieve sufficient welding resistance as an electrical contact. It was difficult to obtain.

Furthermore, when the internal oxidation method is used, the size and distribution of the external and internal oxide particles are different, making it difficult to obtain sufficient welding resistance.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method for producing a silver-oxide contact material that can uniformly and finely disperse oxide particles in a silver substrate.

The method for producing a silver-oxide contact material according to the present invention includes:
Silver-oxide or mixed powder of silver and oxide is thermally sprayed, then the silver-oxide powder obtained by thermal spraying is compressed and sintered one or more times, and then the sintered block is plastic-processed. This method produces a silver-oxide contact material in which oxide particles are uniformly and finely dispersed and solidified in a silver base.

Next, a specific example of the method for manufacturing a silver-oxide contact material according to the present invention will be described based on the drawings.

Example 1 In Figure 1, 1 is 1.5〓mm silver - 12% by weight
This strand 1 is a cadmium oxide wire.The wire 1 is made by mixing electrolytic silver powder and cadmium oxide powder, filling it in a container, compressing it, heating it in an electric furnace at 900°C for 1 hour to make a sintered body, and making it into a sintered body. It is manufactured by applying a wire drawing process to it. The strand 1 produced in this way is
At the same time, the metal wire 1 is introduced into an electric metal spraying machine 2 as shown in the figure, an electric arc is continuously generated at the tip of the spout 3, and the strand 1 is melted by the heat.
Silver-cadmium oxide powder was obtained by squirting it into the solution and rapidly cooling it. This silver-cadmium oxide powder was compressed and sintered twice to form a block, which was then extruded and drawn to obtain a silver-cadmium oxide contact material.

Example 2 After internally oxidizing a 1.5mm silver-10.6% by weight cadmium alloy wire at 700°C, it was introduced into the electric metal spraying machine 2 in the same manner as in Example 1, and an electric arc was applied at the tip of the spout 3. was continuously generated, the alloy wire was melted by the heat, and the alloy wire was spouted into the air to obtain silver-cadmium oxide powder. This silver-cadmium oxide powder was compressed and sintered to form a block, which was then extruded and drawn to obtain a silver-cadmium oxide contact material.

Example 3 Chemical silver powder and tin oxide powder are mixed at a weight ratio of 10:1, and this mixed powder is sucked into a thermal spraying plasma jet device, molten, and squirted into a water tank for rapid cooling. A silver-tin oxide powder was obtained. This silver-tin oxide powder was compressed and sintered twice to form a block, which was then extruded and drawn to obtain a silver-tin oxide contact material.

Each of the silver-oxide contact materials thus obtained has oxide particles uniformly and finely dispersed in the silver base.

However, the silver obtained by the production method of the present invention
Welding resistance tests were conducted on electrical contacts manufactured using oxide contact materials and electrical contacts made of silver-oxide obtained by conventional manufacturing methods. The test results are shown in Figure 2. This represents the number of times of opening and closing until welding. Samples No. 7 and 8 are electrical contacts made from a silver-oxide contact material, and Sample No. 8 is a conventional electrical contact made from a mixed powder of silver and cadmium oxide.
Samples Nos. 9 and 10 are conventional electrical contacts made of silver and cadmium oxide using the internal oxidation method, and Samples No. 11 and 12 are conventional electrical contacts made from a mixed powder of silver and tin oxide.

The test conditions at that time were voltage (DC)
The voltage was 100V, the current was 95A, the energization time was 0.1 seconds, and the rest time after energization was 11.9 seconds.

As can be seen from the test results in Figure 2, the electrical contacts made using the silver-oxide contact material obtained by the production method of the present invention are different from those made using the silver-oxide contact material obtained by the conventional production method. Compared to electrical contacts made from contact materials,
It has an average welding resistance of about 1.3 times.

As detailed above, the silver-oxide contact material manufactured by the manufacturing method of the present invention has oxides uniformly and finely dispersed in the silver base, so when used as an electrical contact, it has a high It has high reliability in terms of weldability and has great industrial utility value.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an apparatus for producing silver-oxide powder in the method for producing a silver-oxide contact material according to the present invention, and FIG. 1 is a graph showing the results of a welding resistance test between an electrical contact made using a silver-oxide contact material and an electrical contact made using a silver-oxide contact material obtained by a conventional method. 1... Silver-oxide wire, 2... Electric metal spraying machine, 3... Spout nozzle, 4... Water tank.

Claims (1)

[Claims] 1 The process of thermal spraying silver-oxide or mixed powder of silver and oxide, the process of compressing and sintering the silver-oxide powder obtained by thermal spraying once or multiple times, and the process of compressing and sintering the silver-oxide powder obtained by thermal spraying, A method for producing a silver-oxide contact material comprising the step of plastically working a silver-oxide block.