JPS59580B2 - Silver-oxide electrical contact materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel electrical contact material, particularly silver-cadmium oxide electrical contact materials, which have been widely used in the past from relatively small current relays to large current ranges such as magnetic switches and breakers. This invention relates to a silver alloy contact material that excludes CdO and contains an alternative oxide instead of the contact material.

Various materials have been used as electrical contact materials, but silver-cadmium oxide contacts in particular have excellent electrical properties such as welding resistance, abrasion resistance, and low contact resistance required for electrical contacts. Therefore, not only is the demand for this material increasing year by year, but the materials have also been improved over time, and there are many academic studies related to this.
It can be said that progress in manufacturing technology has reached its limit.

However, as is known, the production of this silver-cadmium electrical contact material involves many processes that easily discharge cadmium out of the system, such as melting, hot processing, high-temperature oxidation, analysis, and recovery. Efforts must be made to prevent pollution, and for this reason, especially with the expansion of production facilities, large-scale pollution prevention equipment is required, and a large amount of energy is consumed in the prevention, which is about to develop into an energy resource problem.

For this reason, manufacturers of silver-cadmium oxide products have of course taken sufficient measures against this, but just because these measures are sufficient, it is no longer possible to respond to the social situation regarding pollution. If only such points of contact were considered, the huge capital investment would have a serious impact on production prices.

Furthermore, dispersing cadmium oxide in the chain is certainly effective in improving electrical characteristics such as cleaning the contact surface and reducing welding force, but it is not possible to fully achieve these effects. This is especially true in AC circuits, and when this contact material is used in DC circuits where the polarity does not change, it has relatively poor welding resistance and has a significant drawback in increasing contact resistance when the contacts open and close. It has been proposed that the cause of this is that the anode component transfers from the anode side to the cathode side of the contact, forming a type of altered layer at the cathode connection that is different from the contact base material.
This drawback can be said to be a fate that cannot be overcome as long as CdO is used.

Therefore, we solved the pollution problem caused by cadmium as mentioned above,
Moreover, the development of new materials comparable to Ag-Cd0-based electrical contact materials has attracted attention, and recently various researches have begun to be conducted. Academic Journal Vol. 36, No. 8, p. 765 (1)
972)) have also been announced.

However, part of the theoretical basis for such development is that Cd is generally used as a measure of the volatilization of oxides to be dispersed in Ag.
An oxide with a lower vapor pressure is more effective than O, and the use of an oxide with a lower vapor pressure allows the components dissipated from the surface layer of the contact due to the arc that occurs when opening and closing the electrical contact to be diffused into the inside of the contact. It has been proposed that it is effective even if the amount of oxide added to 8g is small because the supplementation ratio is small, and it has actually been proposed to use such an oxide in place of CdO.

In view of the above points, the present invention reconsidered the role of oxides that do not contain Cd components in contributing to the contact characteristics, and as a result, we rejected the preconceived notions mentioned above, renewed our thinking, and conducted repeated research. The basis of this idea is that the cleaning effect on the surface of electrical contacts and various phenomena related to arcs, such as arc extinguishing effects, are
It is based on the idea that it is most closely related to the characteristics of the oxide to be added, especially its vapor pressure and temperature characteristics.

Therefore, the object of the present invention is to reduce the vapor pressure to approximately 500 to 1
Focusing on oxides with a higher vapor pressure than CdO in the temperature range of 500°C, by incorporating sb oxide, which is less toxic, into Ag, surface cleaning of the contact is equivalent to or higher than that of Ag-CdO type. In addition to oxidation of sb, Be, Ca, CoXFeXNi, 5iXTh, and TiXZ, which are difficult to dissolve in Ag, are
By dispersing one type of oxide of r, it is possible to prevent the crystal grains of the alloy from becoming coarse due to medium to high temperature treatment during the alloy manufacturing process, and thereby to further refine the crystal grains.

The feature of the present invention having the above object is that silver is the main component, and sb oxide with a metal component of 0.1 to 6.2% by weight and a metal component of 0.01 to 1.5% by weight are added. Naru Be
XCa, COXF e XN iXS I XT h
%Ti and one kind of oxide of Zr are dispersed.

Although such electrical contact materials can be manufactured by the known sintering method (powder metallurgy method) or internal oxidation method (melting method), the latter method is often used due to production costs5.

In the case of the melting method, sb and the above BeXCa.

By holding a silver alloy containing Co, etc. as a solid solution at a high temperature in an oxidizing atmosphere and continuing the oxidation for a long time while allowing oxygen to penetrate from the surface, Sbc! : Dispersing oxides such as Be, Ca, Co, etc. On the other hand, in the case of sintering, Ag fine powder, Sb1 and Be are used.

Mix powders of Ca, Co, etc., sinter after pressure forming, oxidize and sinter, or mix well with antimony oxide powder, benzium oxide powder, calcium oxide powder, cobalt oxide powder. It is also possible to produce a silver-oxide electrical contact material in which the oxide is dispersed in the chain by pressurizing the powder or the like.

However, no matter what manufacturing method is used at this time, the sb oxide must contain 0.1 to 6.2% by weight of sb, which is the metal component, and this 5 sets the upper limit for the amount of sb added to Ag. 6
．． The reason why it must be limited to 2% by weight is that Ag-S
The maximum solid solubility limit of sb in α individual solution of b alloy is 300
6,2% by weight at °C and exceeding this addition amount sb
This is because, if added, the processability will be significantly inhibited, making it impossible to mass produce the electrical contact material.

Furthermore, even when manufactured by the sintering method, the bonding force between the particles is weak, so arc consumption is large and desirable properties as a contact material cannot be obtained.

On the other hand, if the amount added is less than 0.1% by weight, the addition effect described below cannot be obtained and the purpose cannot be achieved5.
Become.

Furthermore, in the present invention, as described above, <Be, CaXCo, Fe,
NiX5iXThXTi, Zr oxide with 0 metal components
．． It is necessary to disperse in the range of 0.05 to 55 to 5% by weight.

In this case, the above-mentioned additive elements are poorly soluble in Ag, whereas sb is soluble in Ag and does not contribute to the refinement of crystal grains in the recrystallized structure. This addition actively suppresses the growth of crystal grains, maintaining fine crystals even during high-temperature treatments such as internal oxidation, and makes the oxide particles extremely fine, improving arc wear resistance and melting resistance. It has the effect of improving contact characteristics such as.

However, it is not only technically difficult to add more than 2 weight ratios even if we try to improve the addition method; If the amount is less than 0.01% by weight, no effect of suppressing crystal grains or oxide particles can be expected.

Here, one embodiment of the present invention is shown by using raw materials such as AgXSb, BeXCa, and Co having a purity of 99.5 weight coefficient or higher, and by dissolving them in gas in the atmosphere.
An ingot containing 0.3% by weight of Sb3 and 0.3% by weight of Ti is produced in Ag, and after the surface layer of this ingot is face-sided, a thin pure silver plate is thermocompression bonded to one side, and a silver layer for brazing is applied. Form.

Next, the material is cold-rolled into a plate with a thickness of 2 mm, then punched into a disc shape with a diameter of 5 mm using a press machine, and placed in an internal oxidation furnace, without introducing atmospheric air into the furnace. 650℃
The alloy of the present invention was produced by heating for 180 hours to oxidize 5bXTi.

Furthermore, by the same process as the above method, (a) Ag
-3%Sb 0.3%Fe(b)A, g-3%5
b-0,3%N'i (c)Ag -3%Sb -0,3
%C.

)Ag -3%Sb -0.3%Be (E)Ag -3%Sb 0.3%Ca (He)A
g -3rd unit 5b-0, 3rd unit S1 (g) Ag -3%Sb O,
3bTh(ffi Ag -3%Sb -0,3%
A Zr alloy according to the invention was obtained.

For contact testing, the silver layer formed on the back side of the above various alloys and the pedestal for holding contacts were soldered with silver to prepare a sample.
Using an arc wear tester (AC200V, 10A), we selected test conditions for each item listed in the table below while comparing with typical electrical contact materials that have been widely used in the past. Tests were conducted under the same conditions.

As described above, according to the present invention, <Ag-Ca2
It has almost the same properties as the other alloys, and the amount consumed can be reduced considerably, and the number of welds can also be significantly reduced.Of course, the non-use of Cd also eliminates concerns about pollution. did it.

Claims (1)

[Claims] 1 The main component is silver, and the metal component is 0.1 to 6.2
sb oxide and metal component are 0.01 to 1% by weight
．． 5% by weight of Be, CalCoXFelNiXSl
% Th, a type of oxide of TiXZr is dispersed therein.A silver-oxide-based electrical contact material.