JP3070807B2 - Method for manufacturing Ag-NiO electrical contact - Google Patents

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 Ag-NiO electrical contacts.

[0002]

2. Description of the Related Art Ag-CdO electrical contacts containing Cd, particularly CdO, are known to have excellent welding resistance. However, in recent years, there has been a need for electrical contacts that do not contain Cd harmful to the human body due to environmental problems. Is growing. Electrical contact materials that do not contain Cd include SnO ₂ , In ₂ O ₃ , Z
There are electric contact materials in which metal oxides such as nO and BiO are dispersed, and other electric contact materials in which Ni or NiO is dispersed in an Ag base.

Conventionally, as a method for producing an Ag-NiO electric contact material, AgNi is dissolved, and then Ag-Ni powder in which Ni particles are uniformly and finely crystallized in Ag is produced by an atomizing method, and then internally oxidized. Next, there is a method of compressing, sintering, and then plastic working to form required dimensions and shapes. (See Japanese Patent Publication No. 4-75297)

[0004] In this method, when Ag-Ni powder is internally oxidized, compressed and sintered, it has a structure of Ag and NiO, that is, a structure of metal and ceramics. Therefore,
If the content of NiO is 8 wt% or more, the adhesion strength becomes weak, wire drawing is difficult, and cracks occur during header processing. In addition, from the viewpoint of welding resistance, if the content of Ag-NiO is less than 8 wt%, Ni
The amount of O is insufficient.

[0005]

SUMMARY OF THE INVENTION Therefore, the present invention does not cause cracking during header processing, suppresses the occurrence of initial welding,
An object of the present invention is to provide a method for manufacturing an Ag-NiO electrical contact that can improve welding resistance.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a method for manufacturing an Ag-NiO electrical contact according to the present invention comprises the steps of:
Ag-Ni powder is made into Ni melt by atomization method,
Next, this is reduced, and then Ni powder is mixed with this Ag-Ni powder to obtain 8 to 30 wt% of Ag-Ni, compression-molded, sintered, extruded, and drawn to perform wire drawing. And then cut to the required dimensions, cold pressed to the base material and header processed to oxidize internally or Ag-
The method is characterized in that a wire of 8 to 30 wt% of Ni is cut into required dimensions, then internally oxidized, brazed to a base material and processed into a header.

[0007]

As described above, the method for producing an Ag-NiO electric contact of the present invention comprises the steps of:
g-Ni powder, which is then reduced, so that NiO does not occur.
After forming g-Ni of 8 to 30 wt%, compression molding and sintering are performed with Ag and Ni. Therefore, the adhesion strength does not decrease, and the material does not break when extruded and drawn to form a wire. Furthermore, cut to required dimensions,
Cold-welding to the base material and processing the header to perform internal oxidation, or cutting the wire of Ag-Ni 8 to 30 wt% to required dimensions and then internal oxidation, brazing to the base material and processing the header, Since header processing is performed before oxidation, processing cracks do not occur and the resulting Ag-NiO
In the electrical contact, the content of NiO becomes 8 wt% or more, the occurrence of initial welding is remarkably reduced, and the welding resistance is remarkably improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the method for producing an Ag-NiO electric contact according to the present invention will be described. A molten metal of 6.4 wt% of Ag-Ni is converted into 6.4 wt% of Ag-Ni powder by an atomizing method.
Classified with a 0-mesh sieve, Ag-Ni 6.
After obtaining a 4 wt% powder, the powder was subjected to a reduction treatment, and then the Ag-Ni 6.
Ag-N with 4wt% powder mixed with Ni powder of 6 ~ 8μm particle size
After being made 8 wt%, compression molding, sintering, extrusion, wire drawing were performed to obtain wires having a wire diameter of 2.4 mm and a wire diameter of 1.9 mm, and Ag-NiO 10 wt% was obtained by the following two methods. Electrical contacts were obtained.

One of the methods is to use Ag-N having a diameter of 2.4 mm.
i8wt% wire and 2.4mm diameter Ag wire respectively
Cut into 2.1mm and 4.8mm lengths, stack the two chips on a circular surface, cold press weld and process the header, as shown in Fig. 1, head diameter 5mm, head thickness 1mm, legs 2.5
mm, leg length 2.5mm, Ag-Ni 8wt% contact head thickness 0.5mm, rivet type fixed contact with taper 10 degree taper on the head peripheral surface. Ag-Ni 8wt% wire with diameter 1.9mm and diameter A 1.9mm Ag wire was cut into lengths of 2.2mm and 4.3mm, respectively, and these two chips were superimposed on a circular surface, cold pressed and header processed, and the head diameter was 4m as shown in Fig. 2.
m, head thickness 1.1mm, leg diameter 2.0mm, leg length 1.6mm,
A rivet-type movable contact with a thickness of 0.5 mm Ag-Ni 8 wt% contact material on the head, a taper of 10 degrees around the head, and a top surface of 5 mmR is made. These contacts are internally oxidized at 750 ° C and an oxygen pressure of 5 atm. Ag-Ni8wt% contact material of the head is Ag-NiO10
wt% contact material.

Another method is to cut 2.4 mm and 1.9 mm diameter Ag—Ni 8 wt% wires into 2.1 mm and 2.2 mm, respectively, and oxidize them internally at 750 ° C. and at an oxygen pressure of 5 atm to obtain Ag.
-10 wt% of NiO, and each of the 10 wt% of Ag-NiO has a diameter of 2.4 mm, a length of 4.8 mm, a diameter of 1.9 mm, and a length of 4.3 mm.
As shown in FIG. 1, a u-tip was brazed and processed into a header, and as shown in FIG. 1, a head diameter of 5 mm, a head thickness of 1 mm, a leg diameter of 2.5 mm, a leg length of 2.5 mm, and a head material of Ag-NiO 10 wt% contact material. Thickness 0.5
2 mm, rivet-type fixed electrical contacts with a taper of 10 degrees around the head, as shown in Fig. 2, head diameter 4 mm, head thickness 1.1 mm, leg diameter 2 mm, leg length 1.6 mm, head Ag -NiO10wt%
A rivet-type movable electrical contact having a contact material thickness of 0.5 mm, a taper of the head peripheral surface of 10 degrees, and a head upper surface of 5 mmR was prepared.

[0011]

Next, a conventional example will be described.
Ag-Ni 6.4 wt% of molten metal is atomized
wt% powder, then classify with a 200 mesh sieve, 80μm
After obtaining the following Ag-Ni 6.4 wt% powder, it is internally oxidized at 750 ° C. and an oxygen pressure of 5 atm to obtain Ag-NiO 8 wt% powder, then compression molded, sintered, extruded, and drawn. A rivet-type fixed and movable electrical contact of 8 wt% Ag-NiO having the same dimensions was obtained in the same manner as in the example except that the wires were 2.4 mm and 1.9 mm in diameter.

Each of the rivet-type electric contacts having the dimensions and shapes shown in FIGS. 1 and 2 of the embodiment and the conventional example thus formed is fixed to a contact mounting hole of a spring terminal material to form a fixed contact and a movable contact. Figure 3 shows the results of an open / close test conducted at 100 V, an inrush current of 40 A, and a steady current of 10 A to measure the welding resistance.
The following data was obtained. As is clear from this data, the electrical contact of Ag-NiOwt% of the embodiment is the same as that of the conventional example 1
It can be seen that the m value is significantly higher than the electric contact of 8 wt% of g-NiO, the initial welding occurrence rate is low, and the welding resistance is excellent. Also, it can be seen that the life is remarkably longer than that of the conventional electric contact.

DETAILED DESCRIPTION OF THE INVENTION As described above, the Ag-NiO of the present invention
According to the method for manufacturing an electrical contact, an Ag-NiO electrical contact having 8% by weight or more of NiO is easily obtained without cracking during header processing, the occurrence of initial welding is suppressed, and an Ag-NiO having excellent welding resistance is obtained. NiO electrical contacts can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a rivet-type clad electrical contact for a fixed contact made by the manufacturing method of the present invention.

FIG. 2 is a diagram showing a rivet-type clad electrical contact for a movable contact made by the manufacturing method of the present invention.

FIG. 3 is data showing the results of measuring the welding resistance of an electrical contact obtained by the manufacturing method of the present invention and an electrical contact obtained by a conventional manufacturing method by a switching test.

Claims (1)

(57) [Claims] 1. An Ag-Ni melt is made into Ag-Ni powder by an atomizing method, and then reduced, and then the Ag-Ni powder is reduced.
After mixing Ni powder with g-Ni powder to make Ag-Ni 8 to 30 wt%, compression molding, sintering, extruding, wire drawing to form a wire, and then cutting to required dimensions Then, it is necessary to cold-weld to the base material and process the header to perform internal oxidation, or to cut the Ag-Ni 8 to 30 wt% wire into required dimensions and then oxidize internally, braze the base material and process the header. A method for producing an Ag-NiO electrical contact, which is characterized in that: