JPH0949036A - Production of electrical contact - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and efficiently produce a dense silver-oxide electrical contact excellent in hardness and welding resistance and having a long service life by mixing silver powder with oxide powder, filling the resultant mixture into a carbon vessel, compacting and sintering it. SOLUTION: Silver powder of about 5μm size is mixed with oxide powder of about 0.5-2μm size in a ratio of about (86-90):(14-10). The resultant powdery mixture 6 is filled into a carbon vessel 3 with a recess 2 of a large diameter and a recess 1 of a small diameter. The protruding part A of a carbon lid 5 is inserted in the recess 2 and the powdery mixture 6 is press-compacted. The resultant compact is sintered at about 700 deg.C by a spark plasma sintering method to obtain the objective rivet-shaped silver-oxide electrical contact 7 having high hardness and a long contact life.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electrical contact, and more particularly to a method for manufacturing a silver oxide type electrical contact having a long contact life.

[0002]

2. Description of the Related Art Conventionally, to make a silver oxide type electrical contact,
A required amount of silver powder and oxide powder of tin, indium, nickel, etc. are mixed, compression-sintered, and then hot-pressed and sintered repeatedly to form a billet, which is then extruded, wire-drawn, Header processing is performed to make rivet-type silver oxide-based electrical contacts. By the way, the silver oxide-based electrical contact thus produced, for example, AgSnO ₂ 12 wt% electrical contact, has a low hardness of 105 Hv and a low welding resistance, and thus has a short contact life. Further, since there are many manufacturing processes, the work is complicated and the productivity is low.

[0003]

SUMMARY OF THE INVENTION Therefore, according to the present invention, it is possible to easily and efficiently manufacture a silver oxide type electrical contact having improved hardness and welding resistance and a long contact life by a small number of manufacturing steps. It is intended to provide a method for manufacturing an electrical contact.

[0004]

A method of manufacturing an electrical contact according to the present invention for solving the above-mentioned problems comprises mixing a silver powder and an oxide powder in a required ratio, and then filling a carbon container and molding. After that, it is characterized by making a silver oxide type electrical contact by sintering by a spark plasma sintering method.

[0005]

As described above, the method of manufacturing the electric contact of the present invention is
A mixed powder of silver powder and oxide powder is filled in a carbon container, shaped, and sintered by the spark plasma sintering method, so that the obtained sintered body has almost the same theoretical density and is dense. Therefore, no abnormal grain growth has occurred. Therefore, hardness and welding resistance are improved, and the life of the contact is extended. Further, the number of manufacturing steps is reduced, and the manufacturing can be performed easily and efficiently, and the productivity is improved.

[0006]

EXAMPLE An example of a method for manufacturing an electrical contact according to the present invention will be described. No. shown in the left column of Table 1 below. 1 to No.
As shown in FIGS. 1 (a) and 1 (b), an inner diameter of 1.2 m was obtained by mixing silver powder and oxide powder having particle diameters of 3 at respective weight ratios.
A small-diameter recess 1 with a depth of 1.5 mm and an inner diameter of 2.0 mm and a large-diameter recess 2 with a depth of 5 mm are concentrically filled in a carbon container 3 with an outer diameter of 20 mm and a height of 15 mm, and an outer diameter of 2 mm and a length. The convex portion 4 of the carbon lid 5 having an outer diameter of 20 mm and a thickness of 5 mm having the convex portion 4 of 5 mm is fitted into the large-diameter concave portion 2 of the carbon container 3, and each mixed powder 6 is molded at 500 kg / cm ² . Then, after sintering at 700 ° C. for 5 minutes by the spark plasma sintering method (using DR.SINTER manufactured by Sumitomo Coal Industry Co., Ltd.), the rivet type silver oxide type electrical contact 7 shown in FIG. It was When the hardness of the rivet-type silver oxide electrical contact 7 thus produced was measured, the results shown in the right column of Table 1 below were obtained.

[0007]

[Table 1]

As is clear from Table 1 above, No. 1 produced by the method for manufacturing the electrical contact of the embodiment was used. 1 to No. Vickers hardness of rivet type silver oxide type electrical contact 7 of 3 is 145 Hv
With the above, compared to the Vickers hardness of 105 Hv of the rivet-type silver oxide-based electrical contact made by the conventional manufacturing method,
It can be seen that the hardness is improved 1.5 times, and the welding resistance is also improved accordingly. The shape of the contact is not limited to the above-mentioned embodiment, but a desired shape can be obtained by changing the internal shape of the carbon container 3 and the shape of the convex portion 4 of the carbon lid 5. Further, as shown in FIGS. 3 (a) and 3 (b), a large number of electrical contacts can be manufactured at once by using a container having a large number of holes.

[0009]

As can be seen from the above description, according to the method of manufacturing an electric contact of the present invention, a silver oxide type electric contact having a long contact life with improved hardness and improved welding resistance can be obtained. To be Further, the manufacturing method of the electrical contact of the present invention does not require billet creation, extrusion processing, wire drawing processing and the like as in the past, and the electrical contact is directly made from powder, so the number of manufacturing steps is small
It can be easily and efficiently manufactured and productivity is improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of a method for manufacturing an electrical contact according to the present invention.

FIG. 2 is a view showing a rivet-type silver oxide-based electrical contact produced by the method for producing an electrical contact according to the present invention.

FIG. 3 is a diagram showing one example of a carbon container used in the manufacturing method of the present invention.

[Explanation of symbols]

 1 Small Diameter Recess 2 Large Diameter Recess 3 Carbon Container 4 Convex 5 Carbon Lid 6 Mixed Powder 7 Rivet Type Silver Oxide Electrical Contact

Claims (1)

[Claims] 1. A silver oxide and an oxide powder are mixed in a required ratio, then filled into a carbon container and molded, and thereafter sintered by a spark plasma sintering method to form a silver oxide type electrical contact. A method of manufacturing an electrical contact characterized by making.