JPS6020858B2 - Platinum contacts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a platinum-based contact characterized in that a passivation film 2 is provided on the surface of a Pd-Ni-WC contact layer 1 by sulfurization treatment or oxidation treatment, and its purpose is to This is because switching contacts designed with relatively low contact pressure can handle from light loads (e.g. 100 V, 1 skin A) to heavy loads (e.g. 100 V, 1 skin A).
The object of the present invention is to provide a platinum-based contact that is free from welding and adhesion during opening/closing operations up to 20 V (IA), has stable contact resistance, and has high contact reliability.

Precious metals and their alloys are used for the contact points for the follow-up relays.

However, each has its drawbacks; silver-based materials generally corrode in the atmosphere, and gold and gold alloys have a low melting point and become softer as the purity increases, so when used under relatively heavy loads, they tend to settle or deform. Easy to use and extremely consuming. Since platinum-based contacts generally have high hardness and high melting point, they are less prone to welding or deformation and are an excellent contact material, and are widely used. However, in the case of light loads (e.g. 100 V, lmA), an insulating organic polymer called brown powder adsorbs organic gases and impurities such as benzene and toluene in the switching atmosphere and uses the switching energy and catalytic action of the material. The contact resistance tends to increase abnormally during opening/closing operations, resulting in a lack of contact reliability. The present invention aims to eliminate such conventional drawbacks, and will be described in detail below with reference to the accompanying drawings.

The contact layer 1 of Pd-Ni-WC is Pd-N as shown in FIG.
It is made by dispersing WC (tungsten carbide) 4 as carbide particles in i-alloy 3, and an appropriate contact base 5, for example, in the illustrated embodiment, an iron-based material 6, a Cu layer 7, and a Ni layer 8 are sequentially layered laterally. This contact layer 1 is laminated on the surface layer, and a very thin inactivated film 2 is formed on the surface layer of this contact layer 1. Here, sulfurization treatment and oxidation treatment can be considered as the deactivation treatment method for forming the deactivation film 2 here. A. Sulfurization There are various sulfides such as hydrogen sulfide, sodium sulfide, carbon sulfide, thiophene, and cysteine, and there are various sulfurization methods such as immersion in a sulfide solution and exposure to sulfide gas. .

In order to form a very thin sulfide film and obtain practical results,
Although any of the above sulfides and treatment methods may be employed, as a result of various studies, it has been found that the sulfurization treatment using an L-cysteine solution and a sulfur treatment using a thiophene solution is the best. B. Oxidation treatment The surface of the contact layer is coated with a very thin oxide film and inactivated by oxidation treatment.

Some oxidation treatment methods will be described below. (i)
Non-alkaline aqueous solution immersion method: This is a method in which a passive suppuration is formed by immersion in a non-alkaline and highly oxidizing solution (eg nitric acid, sulfuric acid).

As a result of various studies on the type and concentration of acid in this method, it was found that the most desirable treatment method was to introduce it into a nitric acid aqueous solution and form a passive suppuration. (ii) Anodic oxidation It is soaked in an electrolyte aqueous solution and energized with the contact as the anode.

As an anode reaction, OH- ions in the electrolyte are neutralized and discharged,
Generates oxygen. This oxygen causes the Pd--Ni surface to be covered with a passivation film, that is, a very thin oxide film. Gii
) Heat treatment The contact surface is oxidized by heating for a certain period of time in an oxygen atmosphere at a certain temperature.

Generally, in light load opening/closing operations, it is thought that brown powder is caused by the surface adsorption development and staghorn activating effect peculiar to platinum-based materials.

However, in the present invention, as mentioned above, this platinum-based contact is inactivated and the contact surface is coated with a very thin inactivated film. To obtain a contact with high contact reliability, which does not increase contact resistance even if the number of switching operations increases in switching with a light load, and the contact resistance (working characteristics of contact resistance) during switching operations is stable. On the other hand, arcing occurs during opening/closing operations under relatively heavy loads (for example, 20 V, IA).Consequently, contact failure due to Brown Bauder does not occur because the insulating film is destroyed by the arc.
However, there are problems in that contact resistance increases due to arc welding and oxidation and abrasion of the bran material, resulting in instability. Therefore, when opening and closing under heavy loads, it is very important to improve the welding resistance, oxidation resistance, and wear resistance of contact materials. However, in the present invention, the contact layer is made of Pd-Ni-W as described above.
Contacts with this configuration have extremely high performance, for example, 350V in opening/closing operations under heavy loads of 20V and IA. It has become clear that the contact life is longer than 100 times. The contact life was determined when the contact resistance reached 4Q or more. To summarize the contents of the present invention as described above,
The surface of the Pd-Ni-WC contact, which has very high performance in opening and closing operations at zero load (e.g. 20V, IA), is subjected to deactivation treatment to reduce the catalytic activity of Pd, and is treated with a very thin sulfurization treatment or By coating the contact surface with a passivation film through oxidation treatment, it can be used not only under high loads, but also when
Not only this, but also in opening/closing operations under light loads (for example, 100 skin V, 1 desk A), the contact resistance is extremely stable even as the number of operations increases, making it possible to obtain contacts with high contact reliability. There are advantages.

In other words, it is possible to open and close over a wide zero range from light loads to heavy loads, and even if the number of opening and closing operations increases, it is possible to realize a contact with a high degree of shoulder roll. The present invention will be specifically described below based on examples.

Example 1 <Formation of rocky spots> The contact layer was made of Pd-Ni-WC.

That is, in order to increase mechanical strength, Ni was alloyed and its concentration was set to 20% by weight. It was confirmed by X-ray diffraction that Pd and Ni were solidified. Here W.C.
is very finely dispersed in the Pd-Ni alloy, and its amount is about 60% by volume, and its particle size is about 1 French. This P
The d-Ni-WC layer has a thickness of about 5 French, and is made using a palladium-nickel alloy plating solution with PNP80, a trademark of Nippon Seiko Seisakusho, and is composited by mixing WC particles into the plating solution. Obtained by the method of common prayer of plating. still,
The Cu and Ni layers in FIG. 1 are the contact surfaces of Pd-Ni-W.
This was provided to improve the adhesion of the C layer. Each layer is about 3 mm thick and was electrolytically deposited using a plating method. <Sulfiding treatment> The contacts obtained above were treated with L cysteine [C3 days, N
02S] Pd is sulfurized by immersion in an aqueous solution.
-A very thin sulfidic purulent layer was formed on the Ni-WC layer.

The solution concentration was 0.15 molar and the soaking time was 1 minute.
Example 2 The contacts described in Example 1 were flooded in an aqueous nitric acid solution to passivate the contact surfaces.

The nitric acid concentration was 1:1 aqueous solution, and the immersion time was 7 seconds.
Example 3 The contacts described in Example 1 were sulfurized by soaking them in thiophene for 1 minute.

Example 4 The contact surfaces described in Z Example 1 were passivated by anodization.

That is, the contact was made into an anode in a 20% aqueous S04 solution, and the voltage between the electrodes was set to 1 OW. The energization time was set to 3 sand.
Comparative Example The contact of Z Example 1, which was not subjected to inactivation treatment, was used as a comparative example. Opening/closing tests were conducted on the prototype contacts obtained in Examples 1 to 4 and Comparative Example to confirm contact performance.

The switching load level was set to 100 V, IMA to confirm contact performance under light loads, and 2 W, IA to confirm performance under heavy loads, and two types of switching tests were conducted. The test method will be explained as follows.
{1) Light load test (100 mV, lmA) The movable and fixed contacts are opened and closed at a frequency of 10 countries per second in the atmosphere.

When the contact resistance during opening and closing operation becomes 300 or more, it is detected as a contact error, and the number of openings and closings when the initial contact error occurs and the static contact resistance at a certain number of openings and closings are measured. The contact performance was evaluated based on the change in . still,
The final number of opening and closing times was 5000 times. [21 Heavy load test (20V, IA) 2.0% per second in the atmosphere. The contact was opened and closed at a constant frequency, and the life of the contact was determined when the contact resistance reached 40 or higher.

The number of opening and closing times at the end of the technique was set at 3.5 million times. The test results were as shown in the table below. Further, when the changes in static contact resistance under light loads were measured for Examples 1 to 4, the results shown in FIGS. 2 to 5 were obtained.

However, the number of contacts was 10 and the average value was shown. The above test data reveals the following.

○} Pd is removed by coating the contact surface with an inert film.
catalytic activity is significantly reduced, suppressing the generation of brown powder, and as a result, even if the number of openings and closings increases, the contact resistance remains stable and contact errors are less likely to occur. {21 The effect of inert treatment is particularly due to sulfidation treatment with L-cysteine and HN03
Immobilization treatment is good.

[31] The contact performance under heavy loads is the same regardless of the presence or absence of deactivation treatment, and it is thought that the high contact performance before treatment is maintained even after treatment.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway sectional view of an embodiment of the present invention, and FIGS. 2 to 5 are characteristic diagrams of the same. In the figure, 1 indicates a contact layer, and 2 indicates a passivation film. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1. A platinum-based contact comprising a Pd-Ni-WC contact layer and a passivation film formed by sulfurization treatment on the surface of the contact layer. 2. The platinum-based contact according to claim 1, wherein the sulfurization treatment is performed using L-cysteine. 3. A platinum-based contact comprising a Pd-Ni-WC contact layer and a passivation film formed by oxidation treatment on the surface of the contact layer. 4. The platinum-based contact according to claim 3, wherein the oxidation treatment is performed using nitric acid.