JPH05182558A - Manufacture of silver-oxide composite electric contact material - Google Patents

Abstract

PURPOSE:To enhance durability by bonding an Ag-CdO strip to an Ag ribbon by a hot press-fitting method so as to obtain a composite strip. CONSTITUTION:In the mixture atmosphere where N2 gas and CO gas are mixed within a range of volume ratio of 1:1-10:1, a wire or strip made of an Ag-oxide alloy where one or more kind of oxides of Sn, Sb, Zn, Mn, In, Cu, Pb, Te, Bi, Ni, Fe, Co, Cr and Li in addition to CdO are dispersed in Ag is continuously heated at 400 to 800 deg.C by current heating, thus selectively reducing oxide on the surface of the wire or strip so as to form an oxide reducing layer around the wire or strip.

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 wire or strip of Ag-CdO composite electric contact material.

[0002]

2. Description of the Related Art Conventionally, Ag and Ag-N have been used as electrical contact materials.
i or Ag-CdO system is used. Among them, Ag-N
Since i has low contact resistance and little wear, i is widely used instead of Ag. In addition, Ag-Ni is easy to process and spot weld, so it is possible to automate the work of fixing it to the base material, etc., which has the great advantage that the assembly cost is low and the quality is stable. However, on the other hand, Ag
-Because it consumes more than Ag-oxide systems such as -CdO and has poor welding resistance, the range of use is limited to small capacity areas such as small switches.

Recently, the rationalization in each industrial field and the automation of mechanical devices have been remarkable, and the size and complexity of the devices have increased accordingly, and these control systems are rather downsized, the operation frequency is increased, and the capacity is increased. Is required. Therefore, the Ag-Ni system is reviewed, but from the above points, the welding resistance of Ag-Ni becomes a problem, and the development of alternative materials for it is desired.

Therefore, attempts are being made to improve the characteristics by adding various metal elements or metal oxides, nitrides, carbides, etc. to Ag-Ni. However, the stable contact resistance, workability and easiness of spot welding, which are the original features of Ag-Ni system, are hampered by the mixture of various additives, and no satisfactory results have been obtained. On the other hand, the Ag-CdO system is excellent in welding resistance and wear resistance and has a wide range of use, but it has problems in workability and weldability to base materials. This is because the oxide is present at the interface with the base material, so that the joint strength in spot welding or brazing is significantly smaller than that of a non-oxide material.

[0005]

[Problems to be Solved by the Invention] Therefore, these Ag-CdO
A composite material in which an oxide-free layer is formed on the base material for easy spot welding and brazing is considered. For example, a composite strip is obtained by joining an Ag-CdO-based strip and an Ag ribbon by the hot press bonding method, but when actually joining the base material and incorporating it into the switch and performing a test, the Ag-CdO It often separates from the boundary between Ag and Ag and does not reach a predetermined life.

[0006]

[Means for Solving the Problems] The present invention is a kind of oxide of Ag, CdO and Sn, Sb, Zn, Mn, In, Cu, Pb, Te, Bi, Ni, Fe, Co, Cr, Li. Wires or strips of Ag-oxide alloys with the above dispersed, or Ag with Cd and further Sn, Sb, Zn, Mn, In, Cu,
Wires or strips of Ag alloys containing one or more of Pb, Te, Bi, Ni, Fe, Co, Cr, Li added by internal oxidation, or Ag powders and CdO powders and further Sn, Sb, Zn , Mn, In, Cu, Pb, Te, Bi, N
After mixing one or more oxide powders of i, Fe, Co, Cr, and Li, molding and sintering this mixed powder, hot extruding, etc. into a wire or strip of Ag-oxide-based alloy. Ag obtained from internal oxidation method or chemical treatment method is added to CdO and further Sn, S
Hot extruding after forming and sintering powder or small pieces in which one or more oxides of b, Zn, Mn, In, Cu, Pb, Te, Bi, Ni, Fe, Co, Cr, Li are dispersed. The volume ratio of N ₂ gas to CO gas is 1: 1 by molding Ag-oxide type wire or strip with
400 ° C to 80 ° C in a mixed atmosphere mixed in the range of ~ 10: 1
The current problem is solved by continuously heating the wire or strip at a temperature of 0 ℃ to reduce the oxide layer on the surface of the strip or wire and to form an Ag-rich reducing layer on the periphery of the strip or wire. Is what you are trying to do.

Generally, when an oxide of Ag-CdO-based material is to be reduced, a rapid reaction occurs as soon as a reducing gas such as CO and the oxide come into contact with each other, and the inside thereof is full of pores. It will have a sponge shape, resulting in an extremely fragile tissue as a material. Therefore, even if a reducing layer is obtained by contacting it with a reducing gas for the purpose of forming a reducing layer on the surface of a wire or strip by a normal method, the reducing layer is fragile, so brazing or welding to the base material. However, there is a risk of accidents such as contact loss, which is not practical.

In view of the above, the present invention basically uses a wire or strip material having an appropriate working strain, and the volume ratio of N ₂ gas and CO gas as a reducing gas is in the range of 1: 1 to 10: 1. age,
By keeping the reduction temperature constant, a desired reduction layer can be obtained. Here, the volume ratio of N ₂ gas and CO gas is 1:
The reason for setting it in the range of 1 to 10: 1 is that when reducing the oxide layer on the surface of the wire or strip, the volume ratio of CO gas to N ₂ gas is set to control the thickness to a desired uniform thickness. If it is 1: 1.1 or more, it becomes difficult to control the reduction rate, and CO
As the amount of gas increases, safety will be affected. If the volume ratio of CO gas to N ₂ gas is less than 10: 1, CO
This is because the reducing power of the gas is not sufficient and the reducing layer cannot be uniformly controlled.

Further, the reason why cold working is performed on a wire or strip at a cross-section reduction rate of 30% or more is that the cold working of 30% or more causes, in a strict sense, an extremely fine grain in the vicinity of the oxide in the matrix. Cracks are generated, so that CO etc. does not concentrate in the matrix even after heating,
This is because voids are less likely to occur because they are dispersed appropriately. An ideal effect is produced by the synergistic action of such actions.

[0010]

EXAMPLES Examples of the present invention will be described below. First Example 4 mm diameter Ag produced by sintering, molding and extrusion
-13wt% CdO-2wt% SnO ₂ -0.5wt% Bi ₂ O ₃ -0.1wt% Fe wire rod,
A wire with a diameter of 2 mm was drawn by drawing. The cold working ratio at this time was 75%.

By using an electric current heating device in which the volume ratio of N ₂ gas and CO gas is 2: 1, the energizing current is controlled so that the temperature is maintained at 750 ° C. A wire having a reducing layer on the outer periphery of the surface of the wire was obtained. The thickness of the reducing layer at this time was about 0.16 mm. This was further drawn into a wire having a diameter of 1.8 mm, which was designated as sample A.

Second Embodiment 4 mm diameter Ag produced by sintering, molding and extruding
-10wt% CdO-1wt% Bi ₂ O ₃ -1wt% In ₂ O ₃ -0.05wt% CoO wire,
A wire with a diameter of 2 mm was drawn by drawing. The cold working ratio at this time was 75%. The temperature was set at 650 by using a current heating device in which the volume ratio of N ₂ gas and CO gas was 1: 1.
A wire having a reducing layer on the outer circumference of the surface of the wire was obtained by controlling the energizing current so as to be maintained at 0 ° C. and heating continuously.

The thickness of the reducing layer at this time was about 0.16 mm. This was further drawn into a wire rod having a diameter of 1.8 mm, which was designated as Sample B. Samples C to F shown in Table 1 were prepared in the same manner as in the first and second embodiments, and the wire rods of the samples A to F were cut to a length of 2 mm and then spot-welded. The material is stuck.

Next, a forming press was used to form a square having a thickness of 0.8 mm and a width and length of about 2.5 mm. Measure the shear strength of each contact and incorporate it into a commercially available contactor. Voltage 220V, current 78A, power factor 0.35
I did an implementation test. For comparison, the following two most standard conventional examples were prepared and comparative tests were conducted.

In the above embodiment, the method is not limited to the continuous furnace as long as it is a method capable of heating in stages, and the same applies to a batch type furnace. First conventional example Ag-9wt% Cd-2wt% Sn- with a thickness of 5mm, width of 100mm and length of 200mm
0.3wt% Ni alloy plate, thickness 0.5mm, width 100mm, length 200mm
The Ag plates were laminated and joined by the hot pressing method, and cold rolled to a thickness of 0.8 mm.

Next, press punching into a size of 2.5 mm × 2.5 mm was performed, and the pellets were 750 ° C. in the atmosphere.
The internal contact of Ag-10wt% CdO-2wt% SnO ₂ -0.3wt% NiO with the Ag layer formed on the back side was obtained by the internal oxidation treatment in the electric furnace set to. Second conventional example Ag-9wt with Ag layer formed on the back side by the same method as the first conventional example
A contact of% CdO-1wt% Sb ₂ O ₃ -1wt% CuO-1wt% Bi ₂ O ₃ was obtained.

[0017]

[Table 1]

[0018]

According to the present invention described in detail above, as shown in Table 1, the spot welding strength with the base material is excellent,
It has an extremely excellent effect in the contact opening / closing test by the actual machine.

[Procedure amendment]

[Submission date] February 24, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006]

[Means for Solving the Problems] The present invention is a kind of oxide of Ag, CdO and Sn, Sb, Zn, Mn, In, Cu, Pb, Te, Bi, Ni, Fe, Co, Cr, Li. Wires or strips of Ag-oxide alloys with the above dispersed, or Ag with Cd and further Sn, Sb, Zn, Mn, In, Cu,
Wires or strips of Ag alloys containing one or more of Pb, Te, Bi, Ni, Fe, Co, Cr, Li added by internal oxidation, or Ag powders and CdO powders and further Sn, Sb, Zn , Mn, In, Cu, Pb, Te, Bi, N
After mixing one or more oxide powders of i, Fe, Co, Cr, Li, molding and sintering this mixed powder, it was made into a wire or strip of Ag-oxide alloy by hot extrusion . Of Ag, which is obtained by internal oxidation or chemical treatment, and CdO and Sn, Sb, Zn, Mn, In, Cu, Pb, Te, Bi, Ni, Fe, Co, Cr, Li oxides. Molds powder or small pieces in which one or more are dispersed.
After sintering, formed into an Ag-oxide wire or strip by hot extrusion, etc., and mixed with a volume ratio of N ₂ gas and CO gas in the range of 1: 1 to 10: 1. In the atmosphere, 40
The current is continuously heated at a temperature of 0 ° C to 800 ° C to reduce the oxide layer on the surface of the wire or strip, thereby forming a reduction layer rich in Ag on the outer periphery of the wire or strip. It tries to solve the problem.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number for FI Technical indication H01H 1/04 B 7826-5G (72) Inventor Yoshitaka Kajiyama 2-9, Kajicho, Chiyoda-ku, Tokyo No. 12 Stock Company Tokuriki Head Office

Claims (4)

[Claims] 1. Ag with CdO and further Sn, Sb, Zn, Mn, In, Cu, P
The volume ratio of N ₂ gas to CO gas is 1: 1 for the wire or strip of Ag-oxide alloy in which one or more oxides of b, Te, Bi, Ni, Fe, Co, Cr, Li are dispersed. By continuously heating by current heating at a temperature of 400 ℃ ~ 800 ℃ in a mixed atmosphere mixed in the range of ~ 10: 1, selectively reduces the oxide of the surface layer of the wire or strip, A method for producing an Ag-oxide composite electrical contact material, which comprises forming an oxide reduction layer on the outer periphery of a wire or strip. 2. The method according to claim 1, wherein Ag is Cd and further Sn, S.
The wire or strip material of Ag alloy containing one or more of b, Zn, Mn, In, Cu, Pb, Te, Bi, Ni, Fe, Co, Cr, Li is internally oxidized, and the material is used as the cross-section reduction rate. A method for producing an Ag-oxide-based composite electrical contact material, characterized by using a material that has been subjected to a cold working of 30% or more to destroy crystal grains at the time of internal oxidation and leave a working strain inside the material. 3. The powder of claim 1, which is a type of oxide powder of Ag powder, CdO powder, and Sn, Sb, Zn, Mn, In, Cu, Pb, Te, Bi, Ni, Fe, Co, Cr, Li. After mixing the above, molding and sintering this mixed powder, it is formed into a wire or strip of Ag-oxide alloy by hot extrusion, etc., and this material is cold worked with a cross-section reduction rate of 30% or more. A method of manufacturing an Ag-oxide composite electric contact material, characterized by using a material which has been subjected to the above-mentioned process and has a processing strain left inside the material. 4. The Ag obtained by the internal oxidation method or the chemical treatment method according to claim 1, wherein CdO and further Sn, Sb, Zn, Mn,
After molding and sintering a powder or small piece in which one or more oxides of In, Cu, Pb, Te, Bi, Ni, Fe, Co, Cr, Li are dispersed, and then sintered, Ag-CdO is formed by hot extrusion. Molded into a wire rod or strip, and subject this material to a cold reduction of 30% or more as a cross-section reduction rate,
A method for producing an Ag-oxide composite electrical contact material, characterized in that a material having a working strain inside is used.