JPH06349369A - Manufacture of ag-nio electric contact point - Google Patents

Abstract

PURPOSE:To provide an Ag-NiO electric contact point having excellent fusion resistance without forming a crack during working by reducing Ag-Ni atomized powder, adding Ni powder thereto, and by green-compacting, molding, sintering, extruding, and drawing it into wire, which is cut and cold pressure-welded to a base material and then is internally oxidated. CONSTITUTION:A molten Ag-Ni is atomized into powder, and after it is classified into no more than approximately 80mum, it is reduced. Ni powder grain size 6-8mum approx. is added to the Ag-Ni powder, to make the Ag-Ni level 8-30wt.%. The blended powder is compressed, molded, sintered, extruded, and drawn into wire. After the wire is cut into a predetermined size, it is cold pressure-welded to a base material while header working is applied and it is then internally oxidated, or it is internally oxidated and blazed to the base material, and then the header working is applied. An Ag-NiO electric contact point is provided, which forms no crack at the time of header working, in which initial fusion is restricted, and the fusion resistance of which is improved.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for manufacturing an Ag-NiO electrical contact.

[0002]

2. Description of the Prior Art Ag-CdO electrical contacts containing Cd, especially CdO, are known to have excellent resistance to welding, but in recent years there has been a need for electrical contacts that do not contain Cd, which is harmful to the human body due to environmental problems. It is rising. As an electric contact material containing no Cd, SnO ₂ , In ₂ O ₃ , Z in Ag base material is used.
There are electric contact materials in which metal oxides such as nO and BiO are dispersed, but in addition, there are electric contact materials in which Ni or NiO is dispersed in the Ag matrix.

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

By the way, according to this method, when Ag-Ni powder is internally oxidized, and compressed and sintered, Ag and NiO are formed, that is, metal and ceramics are formed. Therefore,
If NiO is 8 wt% or more, the adhesion strength becomes weak, wire drawing is difficult, and cracking occurs during header processing. Moreover, from the viewpoint of welding resistance, if less than 8 wt% Ag-NiO,
The amount of O is insufficient.

[0005]

Therefore, according to the present invention, cracking does not occur at the time of header processing, and the occurrence of initial welding is suppressed.
An object of the present invention is to provide a method for manufacturing an Ag-NiO electric contact capable of improving the welding resistance.

[0006]

A method of manufacturing an Ag-NiO electrical contact according to the present invention for solving the above-mentioned problems comprises an Ag-NiO electrical contact.
The molten metal of Ni was made into Ag-Ni powder by the atomization method,
Next, this is reduced, and then Ni powder is mixed with this Ag-Ni powder to make Ag-Ni 8 to 30 wt%, followed by compression molding, sintering, extrusion, and wire drawing. Then, cut it to the required size, cold press weld it to the base material, process the header and oxidize it internally, or Ag-
It is characterized in that a wire of Ni 8 to 30 wt% is cut into a required size, internally oxidized, brazed to a base material, and processed into a header.

[0007]

As described above, according to the method of manufacturing the Ag-NiO electrical contact of the present invention, the molten Ag-Ni is formed by the atomization method.
Since it is made into g-Ni powder and then this is reduced, NiO does not occur, and then Ni powder is mixed with this Ag-Ni powder to obtain A
When the content of g-Ni is adjusted to 8 to 30 wt%, compression molding is performed and sintering is performed to form Ag and Ni. Therefore, the adhesion strength does not decrease, and the wire does not break when it is extruded and drawn to form a wire. Furthermore, cut it to the required size,
Since it is cold-welded to the base material and header processed for internal oxidation, or the wire of Ag-Ni 8-30 wt% is cut to the required size and then internally oxidized, and brazed to the base material for header processing, that is, internal Since header processing is performed before oxidation, processing cracks do not occur and the obtained Ag-NiO is obtained.
The NiO content of the electrical contact is 8 wt% or more, the occurrence of initial welding is significantly reduced, and the welding resistance is significantly improved.

[0008]

EXAMPLE An example of a method for producing an Ag-NiO electrical contact according to the present invention will be described. A melt of Ag-Ni 6.4 wt% was made into Ag-Ni 6.4 wt% powder by an atomizing method, and then 20
Classify with a 0-mesh sieve to obtain 80 μm or less Ag-Ni 6.
After obtaining 4 wt% powder, reduction treatment was carried out, and then this Ag--Ni 6.
4 wt% powder mixed with Ni powder having a particle size of 6 to 8 μm, Ag-N
i8wt%, compression molding, sintering, extrusion, and wire drawing to make wires with wire diameter 2.4mm and wire diameter 1.9mm. Ag-NiO 10wt% by the following two methods. Got electrical contacts.

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

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

[0011]

PRIOR ART Next, a conventional example will be described. Ag-Ni
Ag-Ni 6.4 wt% 6.4 wt% molten metal was prepared by atomizing.
wt% powder, then classified with a 200 mesh sieve to 80 μm
After obtaining the following Ag-Ni 6.4 wt% powder, internal oxidation was carried out at 750 ° C. and an oxygen pressure of 5 atm to obtain Ag-NiO 8 wt% powder, followed by compression molding, sintering, extrusion and wire drawing. Rivet type fixed and movable electrical contacts of Ag-NiO 8 wt% having the same dimensions were obtained by the same method as in the example except that the wire diameters were 2.4 mm and 1.9 mm.

Each of the rivet type electrical contacts having the dimensions and shapes shown in FIGS. 1 and 2 of the embodiment and the conventional example thus produced are respectively crimped into a contact mounting hole of a spring terminal material to form a fixed contact and a movable contact, and these are AC respectively. A switching test was conducted at 100 V, an inrush current of 40 A and a steady current of 10 A, and the welding resistance was measured.
We obtained the data shown in. As is clear from this data, the electrical contact of Ag-NiOwt% of the embodiment is A of the conventional example 1.
It can be seen that the m value is remarkably higher than that of the electrical contact of g-NiO 8 wt%, the initial welding occurrence rate is low, and the welding resistance is excellent. Further, it can be seen that the life is remarkably longer than that of the conventional electrical contacts.

Detailed Description of the Invention As described above, the Ag—NiO of the present invention
According to the method of manufacturing an electrical contact, cracking does not occur during header processing, and an Ag-NiO electrical contact containing NiO 8 wt% or more can be easily obtained, the occurrence of initial welding is suppressed, and Ag-having excellent welding resistance. NiO electrical contacts can be obtained.

[Brief description of drawings]

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

FIG. 2 is a view showing a rivet-type clad electric contact for a movable contact, which is made by the manufacturing method of the present invention.

FIG. 3 is data showing welding resistance measurement results by an open / close test of an electric contact obtained by the manufacturing method of the present invention and an electric contact obtained by a conventional manufacturing method.

Claims (1)

[Claims] 1. A molten Ag-Ni alloy is formed into an Ag-Ni powder by an atomizing method, which is then reduced, and then this A
After mixing Ni powder to g-Ni powder to make Ag-Ni 8-30wt%, compression molding, sintering, extrusion, wire drawing to make wire, then cut to required size By cold welding to the base material and performing header processing for internal oxidation, or after cutting the wire of Ag-Ni 8-30 wt% to the required size and then performing internal oxidation, brazing to the base material for header processing. A method for producing a characteristic Ag-NiO electrical contact.