JPH10188710A - Electric contact and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric contact suited for use in a breaker for 100A or less rated current. SOLUTION: In this structure, a peripheral layer 2 having 135mHv or more micro Vickers hardness of a contact surface and a central layer 1 less than 135mHv micro Vickers hardness of a section are compounded. The peripheral layer 2 occupies a contact surface region of 32.7% or more 91.0% or less from a contact surface peripheral edge, in an electric contact, the central layer 1 and the peripheral layer 2 are composed of silver alloy 8.0% or more 25.0% or less cadmium(Cd), 1.1% or more 5% or less tin (Sn), 0.07% or more 3% or less nickel(Ni) and 0.2% or less impurity element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a circuit breaker for power distribution,
The present invention relates to an electrical contact used for an earth leakage breaker, a safety breaker, a circuit protector, and the like.

[0002]

2. Description of the Related Art In general, an electrical contact is provided in a power distribution circuit breaker, a no-fuse breaker, an earth leakage breaker, a circuit protector, a safety breaker, and other breakers used for a distribution board (hereinafter collectively referred to as breakers). It is used. Electrical contacts for these breakers include:
Ag alloys are widely used. In this Ag alloy, In oxide, Sn oxide, Cd oxide,
Bi oxide, Co oxide, Ni oxide, Zn oxide, S
An oxide dispersion strengthened alloy in which b oxide, Ca oxide, and the like are dispersed is widely used.

[0003] The characteristics required of this electrical contact include:
(1) welding resistance, (2) initial temperature characteristics, (3) temperature characteristics after overload test, (4) temperature characteristics after durability test, (5)
There are temperature characteristics and insulation characteristics after the cutoff test.

In the case of an electrical contact for a breaker having a rated current of 100 A or less, the electrical contact itself is very small, unlike an electrical contact for a breaker having a rated current of 225 A or more. It is very small and thin compared to the case where the thickness is 225A or more. Also, the method of attaching to the base material supporting the electrical contact may be brazing as in the case of 225 A or more, but it is often the caulking method. In this case, there are many differences, for example, the contact shape is not a granular shape as in the case of 225 A or more, but a screw shape bonded to pure Cu. In the case of 100A or less, it is often necessary to reduce the space in the breaker.

[0005] Therefore, the above-mentioned required characteristics (1) to (5) in terms of the performance required of the electric contact and the optimum contact structure and alloy composition for satisfying the above are 225 A or more and 100 A or less. It is different from the case. In view of the above facts, an object of the present invention is to disclose an electric contact suitable for a breaker application having a rated current of 100 A class or less.

The present invention has an outer layer and a center layer whose hardness and arrangement are controlled, and by optimizing a chemical composition, is an electric contact suitable for a breaker having a rated current of 100 A or less intended by the present application for the first time. Can be offered. Therefore, a material having good conductivity is used as the second layer (lower layer),
Unlike Japanese Patent Application Laid-Open No. 62-97213, in which a layer made of a material having a high hardness is the first layer (upper layer), Japanese Patent Application Laid-Open No.
The first layer is not based on Ag-SnO2 or In2O3 as in JP-A-97-213 and the second layer is not pure Ag, which is different from JP-A-62-97213.

The electrical contact of the present invention has a rated current of 100 A
In the following, among others, the effect is most exerted under the use condition of 60 A or less, and it does not show a contact for further low load use such as a relay. The central layer shown in the present application is mainly for improving the temperature characteristics, and the outer peripheral layer is for improving the welding resistance.

Accordingly, for example, Japanese Patent Application Laid-Open No.
In the case where the first layer (upper layer) is made of a conductor having wear resistance and welding resistance, and the second layer (lower layer) is made of a conductor having good arc breaking at short-circuit current as described in JP-A-189913. This is clearly different from the above-mentioned Japanese Patent Application Laid-Open No. 58-189.
It is not necessary to form irregularities on the boundary surface between the first layer and the second layer as in JP-A-913.

In the present application, Japanese Patent Application Laid-Open No. 58-18991 is also used.
No silver-lithium-based or silver-indium-based material is used for the second layer as disclosed in Japanese Patent Application Laid-Open No. 3 (1993) -313, and the present application is an invention that is different from any known examples in terms of its purpose and configuration.

[0010]

Among the required contact characteristics of the above (1) to (5), some have mutually opposite characteristics, such as temperature characteristics (the smaller the temperature rise due to energization, the better). And the welding resistance are in a trade-off relationship with each other. Therefore, in order to improve the temperature characteristics, the welding resistance must be sacrificed. Previous electrical contacts considered each of these many required characteristics,
Although the work of selecting a contact alloy having an optimal combination of properties was performed, it was impossible to select a contact that fully satisfies all the properties (1) to (5) due to the above trade-off relationship. .

Above all, a breaker contact having a rated current of 30 A or 50 A and a breaker contact of 100 A or less has both temperature characteristics (particularly, initial temperature characteristics and temperature characteristics after an overload test) and welding resistance. It was difficult. For example, even if the welding resistance is good, the initial temperature performance is deteriorated, and the initial temperature (the lower the better) shows a high value, or the state where the good and bad cases occur irregularly occurs in a so-called large variation state. Was.

That is, in the case of a breaker contact having a rated current of 100 A or less, particularly a rated current of 30 A to 50 A, it is difficult to achieve both welding resistance and temperature characteristics. The reason is that it is difficult to develop a contact that satisfies both characteristics that are originally in a trade-off relationship, and the ideal contact alloy composition and structure required to satisfy each individual required characteristic is Because it was not disclosed.

For example, in the case of a contact having a rating of 50 A, what should be the combination of the contact alloy composition and the structure required for improving the welding resistance, and the contact alloy composition necessary for improving the initial temperature characteristics? It should be noted how the combination of structures should be, and how they differ from the optimal combination of contact alloy composition and structure required for welding resistance and initial temperature characteristics when the rated current is 225A. The findings were not always clear.

Further, even if their ideal contact alloy compositions and structures are known, one contact can simultaneously use various ideal contact alloy compositions and structures necessary to satisfy their individual characteristics. It is difficult to combine them, and even if we invent the method of compounding as in the present application in order to combine them, even if we invent the optimal combination of them, for example, what kind of alloy and what alloy to combine in what ratio and in what state It was unclear what the law was.

[0015]

The electric contact of the present invention has a structure in which an outer peripheral layer having a micro Vickers hardness of 135 mHv or more is arranged around the central layer having a micro Vickers hardness of less than 135 mHv to form a composite. It occupies 32.7% or more and 91.0% or less of the contact surface area from the outer peripheral edge of the contact surface. It is also useful that a layer having a micro Vickers hardness of 135 mHv or more is provided in the central layer.

In an electrical contact used for a breaker having a rated current of 100 amperes (A) or less, the center layer and the outer peripheral layer are in a weight percentage of cadmium (Cd) of 8.0% to 25.0%, and tin (Sn) of tin. 1.1% or more and 5% or less, nickel (Ni) is 0.07% or more and 3% or less, and impurity elements are 0.2% or less.
% Or less, desirably 8.0% to 25.0% cadmium (Cd), 1.2% to 4% tin (Sn), and 0.22% to 0.7% nickel (Ni). Is a silver alloy.

In an electrical contact used for a breaker having a rated current of 60 amperes (A) or less, cadmium (C
d) is 14.0% or more and 25.0% or less, tin (Sn) is 2.4% or more and 4% or less, and nickel (Ni) is 0.24%.
A silver alloy of at least 0.7% is used.

Further, in weight%, antimony (Sb) is 0% or more and 2% or less, calcium (Ca) is 0% or more and 0.3% or less, bismuth (Bi) is 0% or more and 1% or less, and zinc (Z
It is also preferable to use a silver alloy in which n) is 0% to 2%, cobalt (Co) is 0% to 0.5%, and indium (In) is 0% to 5%. The thickness of the outer peripheral layer is effective even if it is as thin as 5 μm, and may be 5 μm or more on average.

In the method of manufacturing the electric contact of the present invention, the outer peripheral layer is formed by powder spraying or vapor deposition, or the central layer is formed of an oxidized silver alloy chip, and the outer peripheral layer is formed outside the chip. After arranging the grains of the oxidized silver alloy, press-forming, sintering, immersing and washing in an acidic solution, and surrounding the silver alloy as the central layer that has been annealed and softened, the silver alloy as the outer peripheral layer is formed. A method in which the central layer and the outer layer are integrated and diffusion annealing is performed, and a silver alloy plate serving as the center layer and pure silver (A
g) There is a method in which a silver alloy plate with a layer is punched, annealed, and then oxidized.

Further, a silver alloy cylindrical material as an outer peripheral layer is fitted around a silver alloy rod as a central layer, and the outer boundary between the rod and the cylindrical material is hermetically welded. A silver alloy cylindrical member formed with the silver alloy particles is formed around a cylindrical member formed with a composite structure bar by the forming (HIP) method, or formed with the oxidized silver alloy particles serving as the central layer. A columnar wire is formed by a hot extrusion method to form a cylindrical wire having a composite structure.

Then, a disk-shaped contact is cut out at right angles to the longitudinal direction of the rod or wire and oxidized. It is also effective to form a disk-shaped contact by a forging method in which a silver alloy cylinder serving as a central layer and a silver alloy ring-shaped member serving as an outer peripheral layer are oxidized. The present application shows a method of arranging a high-hardness Ag alloy portion in a peripheral layer around the object and improving the hardness of the Ag alloy in a central layer for the purpose of improving temperature characteristics while maintaining high welding resistance. Further, it shows the optimum alloy composition in this structure.
That is, in the case of a normal contact not having a composite structure as in the present application, the Cd concentration is 8.0% or more and 25.0% or less, the Sn concentration is 1.2% or more and 4% or less, and the Ni concentration is 0.22% or more. When it is 0.7% or less, the temperature characteristics become extremely poor (the temperature rise becomes extremely high) even though the welding resistance is good.

In the contact having the structure shown in the present application, the layer having low hardness at the center has the effect of improving the temperature characteristics. Therefore, the temperature characteristics are not necessarily good because the temperature characteristics are improved by the central layer. No high concentration of Cd, Sn, Ni
Good temperature characteristics can be obtained even when it is contained.

As described above, in the present application, the temperature characteristics satisfy the required characteristics with a composite structure, while the contact alloy composition is increased to a high C value.
By setting d, Sn, and Ni concentrations, high welding resistance can be obtained. That is,
The present invention does not exert a sufficient effect only with the composite structure alone, and the sufficient effect exhibited by the present invention cannot be exerted only by setting the contact alloy composition within the composition range shown in the present application. Even in the case of a composite structure, unless the contact alloy composition is within the above range, high welding resistance cannot be realized. On the other hand, even when the contact alloy composition alone is in the composition range of the present application, excellent temperature characteristics cannot be realized unless the composite structure is used. It is.

Therefore, in the present application, the combination of the contact alloy composition and the composite structure has a relationship that complements the extremely important properties to be improved. The contact alloy composition and the optimum range of the composite structure revealed in the present application are not arbitrarily selected from the respective values, and thus the composite structure and the contact alloy composition have a mutually dependent relationship. After clarifying, the research clarified the contact alloy composition range that shows excellent characteristics in the case of the composite structure.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION
The present invention discloses the results of a study on an ideal composite structure and a contact alloy composition of an electrical contact suitable for a breaker of 0 A or less, particularly 30 A to 60 A. However, the contact is not something that cannot be used for a breaker with a rated current of 225 A or 400 A.

The inventor of the present invention has searched for an optimum contact alloy composition and structure mainly for a contact of 100 A or less, and as a result, the structure of the contact has a composite structure in which an outer peripheral layer 2 is arranged on the outer periphery of a central layer 1 as shown in FIG. I found that it was good. A surface of the composite structure opposite to the contact surface may have a pure Ag layer as shown in FIG. This pure Ag layer is used for improving the brazing property, and the present invention does not prevent the existence of this layer.

The thickness of the outer peripheral layer 2 may be the same as that of the central layer as shown in FIGS. 1 and 2, or the outer peripheral layer 2 is only provided on the surface 8 as shown in FIGS. 3 (a) and 3 (b). May be. For example, the thickness may be half (1/2) of the contact thickness. When the outer peripheral layer is arranged only on the surface portion 8 as shown in FIG. 3, the outer peripheral layer has an average thickness of 5 μm or more, more preferably 10 μm or more.
m or more. This is because the effect of arranging the outer peripheral layer is difficult to be recognized when the thickness is small. As a result of the experiment, if the thickness is less than 5 μm, the effect is small, if not ineffective, and desirably 10 μm or more.

Since the breaker has characteristics depending on the model (spring pressure, tripping force, etc.), it is hard to determine that the contact thickness of the outer peripheral layer must be unconditionally several μm, ie, 5 μm.
Even if it is less than m, the effect is recognized. However, in many cases, it is preferably 5 μm or more,
At μm, the effect of the present application was more effectively recognized.

The micro Vickers hardness is 135 mHv.
In the middle layer that is less than one, as shown in FIG.
Layer having a micro Vickers hardness of 135 mHv or more
1 may be present in a range of 70% or less of the central layer. If the hardness is within this range, the micro-Hickers hardness is 13
This is because it has been found that the effect of the presence of the central layer of less than 5 mHv is not lost, and the welding resistance may be improved in some cases.

Examples in which a Cu screw portion 4 is provided below the electric contact (FIGS. 4, 5, 6, and 7) are shown. An electric contact having a Cu screw portion has a rated current of 100 A or less and is widely and generally used, and is often coupled to the base member 7 as shown in FIG. 8 by, for example, caulking. The Cu screw portion does not significantly affect the contact performance and may or may not be present.

1 to 7, an electric contact according to the present invention has an outer peripheral layer 2 having a micro Vickers hardness of 135 mHv or more disposed on the outer periphery of a central layer 1 having a micro Vickers hardness of less than 135 mHv so that the contact surface becomes flat. The outer layer area is 3 mm from the outer edge of the contact surface.
Occupies an area of 2.7% or more and 91.0% or less.

If the content of the outer peripheral layer is less than 32.7%, the effect of disposing the outer peripheral layer is hardly recognized, so that the welding resistance and some temperature characteristics are deteriorated. Conversely, if it exceeds 91.0%, the temperature characteristics deteriorate. More preferably, it is 32.7% or more and less than 69.8%. This is because in this range, more stable welding resistance and temperature characteristics can be obtained. The contact alloy composition of the central layer and the outer peripheral layer is both weight% and Cd is 8.0%.
Not less than 25.0%, Sn is not less than 1.1% and not more than 5%, N
i is 0.07% or more and 3% or less. (% Is% by weight. The same applies hereinafter.)

If the Cd concentration of this contact alloy composition is less than 8.0%, the welding resistance is lowered, and
As the Cd concentration becomes higher than 5.0%, the production becomes difficult, and a portion of the oxide, called agglomeration, on which the oxide is deposited tends to be generated inside the contact, which is not preferable in terms of the temperature characteristics of the contact.

If the Sn concentration is less than 1.1%, the welding resistance is low, and if it exceeds 5%, the initial temperature characteristics and the temperature characteristics after the overload test among the temperature characteristics deteriorate. Regarding Ni, if it is less than 0.07%, the welding resistance is low, and if it exceeds 3%, the production becomes difficult and the temperature characteristics deteriorate. In particular, Cd is 8.0% or more and 25.0% or less, and Sn is 1.2%.
It is preferable that the Ni content is not less than 0.2% and not more than 0.7%.

The breaker electrical contact having a rated current of 60 A or less has a Cd of 14.0% or more and 25.0 or more.
%, Sn is 2.4% or more and 4% or less, and Ni is 0.24% or less.
When it is set to be not less than 0.7% and not more than 0.7%, the temperature characteristic is slightly deteriorated, but the welding resistance is increased, and it is optimal for a breaker of this class.

Sb added for improving the welding resistance and temperature characteristics is 0% or more and 2% or less, and Ca is 0% or more and 0.1% or less.
3% or less, Bi is 0% or more and 1% or less, Zn is 0% or more and 2% or less.
% Or less, Co is 0% or more and 0.5% or less, and In is 0% or more and 5% or less. These elements are basically C
It was found that as long as the concentrations of d, Sn, and Ni are within the above ranges, contact performance suitable for a breaker of 100 A or less intended by the present application can be expected.

Of course, if the standard values in the performance evaluation of the breaker (the above-mentioned standard values of the temperature and the welding resistance) are relaxed,
For example, even if the Sn concentration is less than 1.1% or more than 5%, it does not mean that it is not usable, and the inventor may be able to do so. We know that even if the value exceeds%, we have taken into account that the breaker is an important device for safety and that there is variation in any product in actual use. In this case, it is considered that it is desirable that the above-mentioned Sn range is still satisfied. The same applies to Cd and Ni.

In general, the elements contained in the contact are the elements as described above, but Cd, Sn, Ni, Sb, Ca, Bi, Z
It is easy to imagine that the same effect can be expected in the case of the composite structure shown in the present application even if a small amount of elements other than n, Co, and In are added. In other words, the present application does not prohibit the addition of a trace amount of an additive element to such an extent that the effect of the present application is not impaired within the range of the contact structure and the contact alloy composition of Cd, Sn, and Ni shown in the present application.

Cd, Sn, Ni, Sb, Ca,
The concentrations of Bi, Zn, Co, and In may be higher or lower than the concentration of the central layer as long as they are within the range of claims 4 to 7. Further, it is not necessary to use an expensive element such as Au for the surface portion.

Further, the outer layer 2 and the center layer 1 are combined by vapor deposition, thermal spraying under reduced pressure, sintering of powder, fitting after acid cleaning / annealing, a plate to be the outer layer and the center layer. Method of forming a plate to be formed by punching, HI
Regardless of P, a method by extrusion, a method of forming an outer peripheral layer and a central layer separately and then forging into a contact shape, the structure and alloy composition of the contact are within the range of the structure and alloy composition shown in the present application. As long as the same effect can be expected.

In addition, a method in which the outer peripheral layer and the central layer are separately formed and then joined by micro welding, shrink fitting, cold fitting, and plating are also conceivable. The same effect can be expected as long as it is within the range of the structure and alloy composition shown in the present application, but it lacks mass productivity from the viewpoint of mass production of products with stable cost and quality at low cost, and also maintains the cleanliness of the bonding interface. It is not always desirable from the viewpoint.

In general, a gradual concentration gradient from the surface toward the inside is generally observed at the internally oxidized contact. However, the composite structure of the present invention, of course, does not exhibit the general concentration gradient observed in the internal oxidation. Even if the outer peripheral layer 2 is formed only near the surface as shown in FIG. 3, FIG. 6 and FIG. Although there is a change in the structure, the outer layer 2 is clearly observed, for example, in the structure observation using an optical microscope.
The difference between the microstructure and the center layer 1 is different from that of the microlayer Vickers.

When the outer peripheral layer is located only near the surface of the contact as shown in FIGS. 3 and 6, it is desirable that the outer peripheral layer has an average thickness of 5 μm or more. In this case, the outer peripheral layer is very thin. Will be. However, in the present application, at least the outer peripheral layer does not refer to, for example, Ag plating applied to the entire contact surface on an extremely small surface of several μm or less from the contact surface. In the present application, a layer having a high hardness (135 mHv or more) is formed only on the outer peripheral portion, and is fundamentally different from the above plating.

However, since it is an industrial product, and the alloy composition and structure of any contact point show a slight change in concentration gradient, structure, and hardness, the outer layer and the center layer are different from each other. In this case, there may be a concentration gradient found in a general internal oxidizing material. The gradient of the hardness distribution accompanying the concentration gradient may have a gradient of the hardness distribution according to the concentration gradient as long as it is in the range of 135 mHv or more in the outer peripheral layer and less than 135 mHv in the central layer.

Further, as a conventional example, in a manufacturing process of a screw-shaped contact, there is a case where heat treatment is performed in a furnace to join a copper base metal and an Ag alloy. In this case, Cd in the vicinity of the surface of the Ag alloy may be dissipated into the furnace, so that the hardness of the surface may be slightly reduced. In such a case, it is usually difficult to manage the hardness distribution of the center layer and the outer layer and the hardness arrangement of the center layer and the outer layer as shown in the present application, and the hardness value is also shown in the present application. Since it is not a very low value, it differs from what is intended by the present application.

In the present application, Sb is 0% or more and 2% or less, Ca is 0% or more and 0.3% or less, and Bi is 0% or more and 1% or less.
Hereinafter, Zn is 0% or more and 2% or less, and Co is 0% or more and 0.5% or less.
% Or less, and even if the In alloy is in the range of 0% or more and 5% or less, as long as it falls within the scope of claim 7, it does not prevent addition of other elements. Absent.

Further, as is well known, for example, Ce is usually added at 0.001% or more and 5% or less, Sb is added at 0.1% or more and 6.2% or less, and 0.01% or more and 5% or less is added. Li added, Si added at 0.05% or more and 10% or less, Fe added at 0.01% or more and 0.5% or less,
Pb added at 0.05% or more and 0.1% or less, 0.00
Cr and Sr added at 1% to 5%, Ti added at 0.5% to 5%, Te added at 0.5% to 5%, and 0.5% to 5% added Mn, 0.
AlF3, MgF2 and C added in the range of 01% to 3%
This does not prevent the addition of rF3 and CaF2, Ge and Ga added at 1% to 3%, and Mg added at 0.01% to 0.1%. In these cases, the same effects as those without these elements can be expected as long as they are within the scope of the configuration described in the claims. This is because the present application does not prevent mixing of elements.

Example 1 A pair of 4 mm long, 4 mm wide, 1 mm thick and 4 mm long, 4 mm wide, 1.2 mm thick (corresponds to the movable contact 5 and the fixed contact 6 in FIG. 8; FIG. 7 to 7 indicate fixed contacts for the sake of explanation). Each of the electrical contacts has a pure Ag layer having a thickness of 10%, and the recesses in the vapor deposition layer forming portion serving as the outer peripheral layer (Tables 5 and 6 show the recesses). , The outer peripheral layer ratio is also shown as 0.8%), and the contact alloy composition is as shown in Tables 1 and 2 ("P" in the column of the method. The same applies to Tables 3 to 6). ) Is formed, and the surface (the surface opposite to the pure Ag) of the alloy having the composition shown in Tables 3 and 4 is formed by a reduced pressure plasma spray method in an atmosphere of argon and hydrogen gas (Ar + H2). The powder was sprayed to form an outer peripheral layer. Table 1 shows the contact alloy composition of the center layer, and Table 2
Is a contact alloy composition of the center layer, and shows a comparative example.

[0049]

[Table 1]

[0050]

[Table 2]

As a raw material, a prealloy powder was used, and a powder having a particle size of 1 μm or less to 2 μm was used. Ar was used as a carrier gas for the feed. In addition, during spraying, the tip of the spray gun is swung by automatic control to form a uniform sprayed layer and, at the same time, increase the adhesion between the inner layer of the electrical contact that becomes the subsley and the sprayed layer, and apply the plasma spray to the substrate. After spraying and heating, thermal spraying was performed. In order to make it easier to provide a thermal spray layer on the concave portion, that is, to prevent thermal spraying on the central layer other than the concave portion, the central layer other than the concave portion was masked. Table 3 shows the contact alloy composition of the outer peripheral layer, and Table 4 shows the contact alloy composition of the outer peripheral layer (Comparative Example).

[0052]

[Table 3]

[0053]

[Table 4]

Tables 5 and 6 show the structure and hardness of the resulting electrical contacts after oxidation. These contacts are rated 100A
In the following breakers, the results of the breaking test at 220 V, 5 kA breaking current and the evaluation of the initial temperature measurement, the temperature characteristics after the overload test, the temperature characteristics after the durability test, and the temperature characteristics after the short circuit test are shown in Table 5 ( The results are shown in Table 6 (Evaluation results of Comparative Example). In addition, the column of H (*) display in Table 5 shows that the micro Vickers hardness is 135 mH in the center layer.
This is a case of a three-layer structure in which 10% or more regions exist.

[0055]

[Table 5]

[0056]

[Table 6]

The overload test conditions were 6 times the rated current and 50
And the endurance test was performed 5000 times at the rated current. When the evaluation is performed with a Cu screw portion as shown in FIG. 4, Cu bonding is performed by brazing or direct bonding by heating and pressing.
A screw portion was prepared. In addition, since the evaluation results differed depending on the evaluation breaker, the overall evaluation was shown as 5-1. The best result is indicated by 5, the lower usable limit is indicated by 3, and the worst result is indicated by 1.

Example 2 A pair of electrical contacts having a length of 4 mm, a width of 4 mm, a thickness of 1 mm and a length of 4 mm, a width of 4 mm, and a thickness of 1.2 mm, and a pair of electrical contacts having a diameter of 6 mm and a thickness of 1.5 mm Contact points, each of which is 10% pure A
g layer, and the dent of the vapor deposition layer
A surface of a contact base material which is provided at a depth of μm and has an inner layer of a contact having a contact alloy composition shown in Tables 1 and 2 (the description of “steam” in the column of “method”; the same applies to Tables 3 to 6) Using a target having the contact alloy composition shown in Tables 3 and 4, vapor deposition was performed on the surface opposite to the pure Ag by magnetron sputtering.

The temperature of the base material 7 is maintained at 200 ° C. in order to prevent re-evaporation of Sn, and the pressure is reduced to several torr (to
rr) to a few tens of torr (torr). In addition, in order to improve the adhesion between the inside of the contact, which is the base material, and the outer peripheral layer, which is the vapor deposition layer, the surface of the contact base material, which is to be the contact center layer, is previously cleaned with ions generated by high frequency and then subjected to vapor deposition. went. After the obtained contacts were oxidized, these contacts were evaluated for the breaking test, initial temperature measurement, temperature characteristics after overload test, temperature characteristics after overload test, and temperature characteristics after short circuit test under the same conditions as in Example 1. The results are shown in Tables 5 and 6 together with the hardness.

Example 3 The contact alloy compositions were as shown in Tables 1 and 2.
(Ag corresponds to the central layer shown in FIG. 9) so that “Powder” is described in the method column. The same applies to Tables 3 to 6.
Alloy chip 10 (when the pure Ag layer 11 is provided,
0%) and after oxidation, Table 3,
Ag alloy grains 9 corresponding to the oxidized outer peripheral layer having the composition of No. 4 (the same composition as in Tables 1 and 2) were arranged, pressed, and sintered at a temperature of 30K below the melting point in a vacuum atmosphere. The obtained composite alloy chip 12 was coined and annealed at about 650 ° C. Thus, a pair of electrical contacts having a length of 4 mm, a width of 4 mm, and a thickness of 1 mm, and a length of 4 mm, a width of 4 mm, and a thickness of 1.2 mm were produced.

These contacts were evaluated for the breaking test, the initial temperature measurement, the temperature characteristics after the overload test, the temperature characteristics after the overload test, and the temperature characteristics after the short-circuit test under the same conditions as in Example 1 together with the hardness. 5 and 6.

(Example 4) A member having a pure Ag layer having a composition of Tables 1 and 2 (the description of "acid + baking" in the column of the method; the same applies to Tables 3 to 6) as the central layer was used. After being immersed in an acidic solution to remove and clean the surface, the alloy was annealed to soften the alloy. Around this, a ring-shaped member to be an outer peripheral layer having a contact alloy composition as shown in Tables 3 and 4 was produced, and after being fitted, further annealed and integrated by diffusion.

Tables 5 and 6 show the structure and hardness of the resulting composite contact after oxidation. These contacts were subjected to a cutoff test, initial temperature measurement, temperature characteristics after an overload test, temperature characteristics after an overload test, and temperature characteristics after a short circuit test under the same conditions as in Example 1.

Example 5 The contact alloy compositions were as shown in Tables 1 and 2.
(A description of “plate” corresponds to the column of the method. The same applies to Tables 3 to 6.) Ag with a pure Ag layer to be the central layer.
An alloy plate was prepared and punched together with an alloy plate having the composition shown in Tables 3 and 4 to form an alloy having a composite structure including a central layer and an outer peripheral layer. The outer layer has a forging ratio of 30% compared to the central layer.
It was raised and forged. Thereafter, annealing was performed at a temperature of 700 ° C. for 5 hours.

Table 3 shows the structure and hardness of the contact having the composite structure obtained by oxidation. These contacts were subjected to a cutoff test, initial temperature measurement, temperature characteristics after an overload test, temperature characteristics after an overload test, and temperature characteristics after a short circuit test under the same conditions as in Example 1.

Example 6 The contact alloy compositions were as shown in Tables 1 and 2.
(The description of "HIP" corresponds to the column of the method. The same applies to Tables 3 to 6.) A silver alloy rod 13 to be a central layer is prepared and oxidized, and the surface thereof is oxidized. The silver alloy cylindrical material 14 having the following composition was fitted, and the outer boundary 16 between the silver alloy rod and the silver alloy cylindrical material was welded to be airtight. FIG. 10A shows the fitted member 15. Thereafter, HIP was performed in an Ar gas at a temperature of 700 ° C. and a pressure of 1800 kg / cm 2 for 2 hours to obtain a composite-structured bar.

This was cut from a direction perpendicular to the longitudinal direction, and a finished pure Ag layer was bonded to a disc-shaped contact. This disk-shaped contact was evaluated under the same conditions as in Example 1 for a breaking test, initial temperature measurement, temperature characteristics after an overload test, temperature characteristics after an overload test, and temperature characteristics after a short-circuit test.

Separately from this, the silver alloy cylindrical material 14-1
A silver alloy rod 13-1 is fitted in advance, air-tight by welding, and then fitted to the silver alloy cylindrical material 14, and a triple-fitted member 15-1 which is air-tight by welding. (FIG. 10
(B). ) Was also evaluated under the same conditions as in Example 1.

Example 7 Next, the compositions of the contact alloys are shown in Tables 1 and 2 ("Extrusion" is described in the column of the method. Tables 3 to 3)
Same for 6. 11), a cylindrical member 17 as shown in FIG. 11 which is to be the central layer 1 is formed by molding oxidized Ag alloy particles, and the oxidized Ag which is to be the outer peripheral layer 2 having the composition shown in Tables 3 and 4 is formed therearound. A cylindrical billet having a diameter of 80 mm and a length of 200 mm was formed by joining cylindrical members 18 formed by molding alloy grains into a cylindrical shape.

After that, Ar was added at a temperature of 800 ° C. for 2 hours.
After heating in an atmosphere, extrude hot and perform cylindrical wire 1
After setting to 9, the cylindrical wire 19 was cut in a direction perpendicular to the longitudinal direction to produce a disc-shaped contact. A pure Ag layer plate having a thickness of one tenth (1/10) of the thickness of the disc-shaped contact was bonded and then oxidized to produce a contact having a diameter of 5 mm and a height of 1.5 mm. A breaking test was performed on the contacts under the same conditions as in Example 1,
The initial temperature measurement, the temperature characteristics after the overload test, the temperature characteristics after the overload test, and the temperature characteristics after the short circuit test were evaluated.

Example 8 Next, contact alloy compositions are described in Tables 1 and 2 ("Forging" is described in the column of method. Tables 3 to 6).
The same is true. )) To be a central layer having a composition as shown in FIG. 12 (with a pure Ag layer 22 having a thickness of 12% of the height) as shown in FIG.
And a ring-shaped member 20 (a ring-shaped member having the same outer diameter as the cylinder 21) to be an outer peripheral layer having the chemical composition shown in Tables 3 and 4.
The pure Ag layer 22 was inserted into the center of the ring-shaped member 20 by forging to form a disc-shaped contact having a diameter of 6 mm and a height of 1.8 mm.

After this disk-shaped contact was oxidized, a breaking test was performed under the same conditions as in Example 1, and the initial temperature measurement, the temperature characteristics after the overload test, the temperature characteristics after the overload test, and the temperature characteristics after the short-circuit test were performed. evaluated.

The results of the tests of Examples 1 to 8 are shown in Tables 1 to 6 together with Comparative Examples. That is, the comparative examples ((11) to (16)) in Table 2 are those in which the contact layer alloy composition of the center layer deviates from the present invention, and the comparative examples (K to P) in Table 4 are those in which the contact layer alloy composition of the outer layer is not. Table 6 Comparative Examples deviating from the present invention show that the first six have the contact alloy composition of the outer layer, the next six have the contact alloy composition of the center layer, and the next three have the outer layer thickness and hardness. However, the final comparative example is different from the present invention in the rated current of the evaluation. As a result, the contact point shown in the present invention showed clearly superior temperature characteristics and welding resistance characteristics as compared with the comparative example.

[0074]

According to the present invention, excellent temperature performance (initial, after overload test, after endurance test, and excellent temperature performance) is achieved by a structure (including hardness) and a contact alloy composition suitable for use in electrical contacts having a rated current of 100 A or less. (After a short-circuit breaking test) and excellent welding resistance can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a cross section of a fixed contact of the present invention.

FIG. 2 is a diagram showing a cross section of another fixed contact.

FIG. 3 is a diagram showing a cross section of a fixed contact in a case where an outer peripheral layer exists only on a surface portion.

FIG. 4 is a view showing a cross section of a contact when a Cu screw portion is provided on the fixed contact of FIG. 1;

5 is a view showing a cross section of the fixed contact in FIG. 2 when a Cu screw portion is provided.

FIG. 6 is a view showing a cross section of the contact in the case where a Cu screw portion is added to the fixed contact of FIG. 3 (a).

FIG. 7 is a view showing a cross section of the fixed contact of FIG. 3 (b) when a Cu screw portion is provided.

FIG. 8 is a conceptual diagram showing a pair of electric contacts (movable contact, fixed contact).

FIG. 9 is a cross-sectional view of a composite alloy chip in which Ag alloy particles are arranged on an Ag alloy chip. (Example 3)

FIG. 10 is a view showing a silver alloy rod and a silver alloy cylindrical material before HIP, and a state where they are fitted. (Example 6)

FIG. 11 shows before and after hot extrusion.
(Example 7)

FIG. 12 is a view showing a ring-shaped member to be forged and a cylinder with a pure Ag layer. (Example 8)

[Explanation of symbols]

 1: Central layer 1-1: Another layer in the central layer 2: Peripheral layer 3: Pure Ag layer 4: Cu screw portion 5: Movable contact 6: Fixed contact 7: Base material 8: (Contact) surface 9 : Ag alloy particle 10: Ag alloy chip 11: Pure Ag layer 12: Composite alloy chip 13: Silver alloy rod (before HIP) 13-1: Another silver alloy rod (before HIP) 14: Silver alloy cylindrical material (before HIP) 14-1: another silver alloy cylindrical material (before HIP) 15: fitted member 15-1: another fitted member 16: outer boundary portion between silver alloy rod and silver alloy cylindrical material 17: cylindrical member 18: cylindrical member 19: columnar wire 20: ring member 21: column 22: pure Ag layer

Continuation of the front page (51) Int.Cl. ⁶ Identification code FI C23C 14/14 C23C 14/14 D 30/00 30/00 A H01H 11/04 H01H 11/04 B (72) Inventor Kobayashi Akira 1-1 1-1 Kunyokita, Itami-shi, Hyogo Sumitomo Electric Industries, Ltd. Itami Works

Claims (15)

[Claims] An electrical contact for use in a circuit breaker (breaker) having a rated current of 100 amperes (A) or less, wherein at least the contact surface has a micro Vickers hardness of 13
Outer layer of 5 mHv or more and micro Vickers hardness 135
An electric contact, wherein the electric contact has a structure in which a central layer having a mHv of less than mHv is compounded, and an outer peripheral layer area is 32.7% or more and 91.0% or less from an outer peripheral edge of the contact. 2. The method according to claim 1, wherein a layer having a micro Vickers hardness of 135 mHv or more is provided in the central layer.
Electrical contacts as described. 3. The electrical contact according to claim 1, wherein the thickness of the outer peripheral layer is 5 μm or more on average. 4. The method according to claim 1, wherein the weight of the central layer and the outer peripheral layer is not less than 8.0% and not more than 25.0% of cadmium (Cd).
n) is 1.1% or more and 5% or less, and nickel (Ni) is 0.1% or more.
The electrical contact according to any one of claims 1 to 3, wherein the silver alloy is a silver alloy having a content of from 07% to 3% and an impurity element of 0.2% or less. 5. The method according to claim 1, wherein the central layer and the outer peripheral layer are in a weight percentage of cadmium (Cd) of not less than 8.0% and not more than 25.0%, and tin (Sd).
n) is 1.2% or more and 4% or less, and nickel (Ni) is 0.1% or more.
The electrical contact according to any one of claims 1 to 3, wherein the electrical contact is a silver alloy of 22% or more and 0.7% or less. 6. An electrical contact used for a circuit breaker (breaker) having a rated current of 60 amperes (A) or less, wherein cadmium (Cd) is 14.0% or more and 25.0% or less and tin (Sn) is 2% by weight. The electrical contact according to any one of claims 1 to 3, wherein the electrical contact is a silver alloy of not less than 4% and not more than 4% and nickel (Ni) is not less than 0.24% and not more than 0.7%. 7. An antimony (Sb) of 0% or more and 2% or less, a calcium (Ca) of 0% or more and 0.3% or less, a bismuth (Bi) of 0% or more and 1% or less, and a zinc (Z
7. A silver alloy wherein n) is 0% or more and 2% or less, cobalt (Co) is 0% or more and 0.5% or less, and indium (In) is 0% or more and 5% or less. An electrical contact according to any one of the preceding claims. 8. The contact layer according to claim 1, wherein a recess is formed outside a region serving as a central layer on the surface of the contact, and a silver alloy is sprayed on the recess by a powder spraying method to form an outer peripheral layer. The method for producing an electrical contact according to any one of the preceding claims. 9. The method according to claim 1, wherein a recess is formed outside a region serving as a central layer on the contact surface, and a silver alloy is deposited on the recess by a vapor deposition method to form an outer peripheral layer. A method for producing an electrical contact according to any one of the preceding claims. 10. The method according to claim 1, wherein the central layer is formed of an oxidized silver alloy chip, and oxidized silver alloy particles serving as an outer peripheral layer are arranged on the outer side of the chip. The method for producing an electrical contact according to any one of claims 1 to 3, wherein 11. After immersion and washing in an acidic solution, a silver alloy serving as an outer peripheral layer is fitted around a silver alloy serving as an annealed and softened central layer, and the central layer and the outer peripheral layer are integrated and diffusion-annealed. The method for producing an electrical contact according to any one of claims 1 to 3, wherein 12. The method according to claim 1, wherein the silver alloy plate as the central layer and the silver alloy plate with a pure silver (Ag) layer as the outer peripheral layer are punched, annealed, and then oxidized. 2. The method for producing an electrical contact according to claim 1. 13. Around the silver alloy rod serving as the central layer,
After fitting a silver alloy cylindrical material serving as an outer peripheral layer and hermetically welding an outer boundary portion between the rod and the cylindrical material, hot isostatic pressing (HI
The bar according to any one of claims 1 to 3, wherein a bar having a composite structure is formed by the P) method, and a disc-shaped contact is cut out at right angles to a longitudinal direction of the bar and oxidized. Manufacturing method of electrical contacts. 14. A silver alloy cylindrical member formed of silver alloy particles is bonded in a cylindrical shape around a cylindrical member formed of oxidized silver alloy particles serving as the central layer, and is subjected to hot extrusion. 4. A cylindrical wire having a composite structure is formed by cutting a disk-shaped contact at right angles to a longitudinal direction of the wire to oxidize the wire. Manufacturing method. 15. The disk-shaped contact according to claim 1, wherein a silver alloy cylinder serving as a central layer and a silver alloy ring-shaped member serving as an outer peripheral layer are formed by integral forging and oxidized. The method for producing an electrical contact according to claim 1.