JPH05234453A - Manufacture of rivet type clad electric contact - Google Patents

Abstract

PURPOSE:To provide a rivet type clad electric contact in which silver in a silver-oxide compound contact material and another silver forming a basic material are mutually diffused on the whole surface of a joint portion between the contact material and the basic material to prevent the joint portion from being swelled so as to heighten the conjoining strength of the two materials, and also which can stably break and make a circuit without causing the contact material to be peeled off the basic material by arc heat or Joule heat when the contact is incorporated in a relay, a switch or the like and load is applied. CONSTITUTION:Cold pressure welding is given to both of a contact material made of a silver-unoxide and a basic material made of silver so as to form a rivet type contact. Then the contact is heat-treated in an atmosphere of nitrogen gas kept at a temperature of not less than 350 deg.C, and thereafter the contact is oxidized to change the silver-unoxide forming the contact material into its corresponding silver-oxide one.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a rivet-type clad electrical contact used for a relay, a switch, etc., in particular, when a load is applied, the contact material does not separate from the base material due to arc heat or Joule heat. , A method of manufacturing an electrical contact that can be stably opened and closed.

[0002]

2. Description of the Related Art In one conventional method for producing a rivet-type clad electrical contact, a contact material made of silver-unoxide and a silver base material are cold-pressed to form a rivet shape, and then oxygen There is a method in which the contact material is converted to silver-oxide by heating and oxidizing it at 600 ° C to 850 ° C in the presence. (As a prior art document, there is Japanese Examined Patent Publication No. 56-8448.)

By the way, in the above-mentioned method of manufacturing a rivet-type clad electrical contact, when the clad contact formed by cold pressure welding into a rivet type is oxidized, the gas at the joint expands and peels off from the joint and swells. Occurs. Therefore, mass production is difficult.

[0004]

SUMMARY OF THE INVENTION Therefore, the present invention seeks to provide a method for producing a rivet-type clad electrical contact that can be stably opened and closed without causing swelling due to expansion of gas at the joint during oxidation. It is a thing.

[0005]

A method of manufacturing a rivet-type clad electrical contact according to the present invention for solving the above-mentioned problems, comprises:
After the contact material made of silver-unoxide and the silver base are cold pressed to form a rivet type, then heat treated in nitrogen gas at 350 ° C or higher to diffuse the contact material and the base material mutually. It is characterized in that the contact material is oxidized to be a silver oxide. It is preferable that the temperature of the oxidation treatment is maintained at 450 ° C. to 590 ° C. for 10 minutes or more, and then the temperature is gradually raised to perform the oxidation at 650 ° C. to 750 ° C.

[0006]

As described above, in the method for producing a rivet-type clad electrical contact of the present invention, the rivet-type clad contact formed by cold pressure welding is heat-treated in nitrogen gas at 350 ° C. or higher before being oxidized. The silver on the side of the contact material and the silver on the side of the base material diffuse with each other, and the bonding strength increases. Furthermore, by oxidizing at a low oxidation temperature of 450 ° C to 590 ° C in the initial stage of oxidation, ultra-fine oxide is generated at the joint between the contact material and the base material, further increasing the joint strength. The blister phenomenon does not occur.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment and a conventional example of a method for manufacturing a rivet-type clad electrical contact according to the present invention will be described.

First of all, an embodiment will be described. A contact material made of silver-cadmium and a silver base material are cold-welded to each other to obtain a diameter 3.5 of an oval-shaped head 1 as shown in FIG.
mm, thickness 0.8 mm, thickness of contact material 2 of head 1 0.5 mm, thickness of base material 3 0.3 mm, diameter of base material 3 of leg 4 2.0
It was molded into a rivet mold with a height of 1.5 mm and a height of 1.5 mm. Next, this rivet-type clad contact 5 was heat-treated for 30 minutes in a furnace in a nitrogen gas atmosphere at 450 ° C. After that, the rivet-type clad contact 5 was held at 550 ° C. for 2 hours, then raised by 50 ° C. every 30 minutes and oxidized at 750 ° C. to make the contact material 2 silver-cadmium oxide.

Next, a conventional example will be described. After molding a rivet-type clad contact 5 having the same size and the same material as those of the above-mentioned embodiment, the contact material 2 is silvered by oxidizing it in a furnace at 750 ° C. in an air atmosphere. -Tin oxide.

Each of the rivet-type clad electric contacts of the example thus obtained and the conventional rivet-type clad electric contact of 100
As a result of inspecting the cross-sectional structure of each piece, 87 rivet-type clad electrical contacts on the conventional side were found to have blisters at the contact material joints on the outside of the legs. No blister was observed at the joint of the contact material.

[0011]

As described above, according to the method of manufacturing a rivet-type clad electrical contact of the present invention, the silver on the silver-oxide contact material side and the silver on the base material are mutually diffused over the entire joint portion and swell. The rivet-type clad electrical contact that prevents the contact from peeling off from the base material due to arc heat and Joule heat when mounted on relays, switches, etc. Obtainable.

[Brief description of drawings]

FIG. 1 shows a rivet-type clad contact before oxidation.

[Explanation of symbols]

 1 Head 2 Contact material 3 Base material 4 Legs 5 Rivet type clad contact

Claims (2)

[Claims] 1. A silver-unoxide contact material and a silver base material are cold pressed to form a rivet mold, and then 350 ° C.
A method for producing a rivet-type clad electrical contact, characterized in that the contact material is heat-treated in the above nitrogen gas and then oxidized to make a silver-oxide contact material. 2. The method for producing a rivet-type clad electrical contact according to claim 1, wherein the oxidation treatment temperature is 450 ° C. at the initial stage.
~ 590 ℃, then 650 ℃ ~ 750 ℃, a method for producing a rivet-type clad electrical contact, characterized in that.