JPH08298039A - Sealed contact material and its manufacture, and manufacture of sealed contact and its use - Google Patents

Abstract

PURPOSE: To provide a sealed contact material minimized in dispersion of contact resistance and excellent in operating life characteristic by providing, on the surface of a contact base, a coating layer having a specified thickness in which one kind is selected from a specified element group, and added to a matrix in a specified atomic %. CONSTITUTION: A contact material A is formed of a contact base 1 such as Fe-Ni and a contact coating layer 2A formed so as to cover its surface. The coating layer 2A is formed of a material which has at least one kind selected from the group consisting of Mo, Zr, Nb, Hf, Ta, and W as a substantial matrix, the matrix containing 0.5-50 atomic % of at least one element selected from the group consisting of Zn, Cd, Hg, Al, Ga. In, Te. Ge. Sn, Pb, As, Sb, and Bi, and its thickness is set to 0.1μm or more. Since the surface is roughed to easily bring about an increase in contact resistance when the coating layer is too thick, and the cost of film formation is also raised, the upper limit is preferably set to 100μm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encapsulated contact material, a method for manufacturing the encapsulated contact material, and a method for manufacturing and using the encapsulated contact. More specifically, the contact resistance variation during opening / closing operation is small and the operating life characteristics are excellent. And an encapsulated contact material that can be manufactured at low cost.

[0002]

2. Description of the Related Art A sealed contact used in a reed switch or the like has a structure in which a sealed contact material is sealed together with N ₂ gas in a sealed container made of glass or the like. . Conventionally, as the encapsulated contact material,
It has been widely used that the contact base material is made of, for example, an Fe—Ni alloy, and the surface thereof is coated with Rh, Ru or the like to function as a contact coating layer. This is a material such as Rh and Ru having excellent electric conductivity, high hardness and high melting point,
Moreover, it is also excellent in wear resistance.

In the above-mentioned conventional encapsulated contact material,
First, a metal such as Ag, Au, or Cu is plated on the surface of the contact base material by, for example, an electroplating method to form an intermediate layer, and then Rh, Ru or the like is plated thereon to form a contact coating layer. Was manufactured by This intermediate layer enhances the adhesion between the contact base material and the contact coating layer, and prevents Rh, Ru, etc. of the contact coating layer from diffusing into the contact base material at the time of opening / closing the contact. It is provided.

However, the above-mentioned encapsulated contact material is
Since expensive Rh, Ru, etc. are used, the material cost becomes high, and this is regarded as a problem in terms of economy. Therefore, recently, Fe-Ni alloy or the like is still used for the contact base material as in the conventional case, and Mo is used for the contact coating layer.
Encapsulated contact materials with reduced material cost have been proposed by using high melting point materials such as W and W or their alloys.

Among the properties required for the contact coating layer, this encapsulated contact material is excellent in terms of high melting point, high hardness and high conductivity. However, it is becoming clear that this material behaves as follows. That is, for example, in the case where the contact coating layer is made of W, a contact use test in which the switching operation is repeated at 10 Hz causes a large variation in contact resistance, and often the occurrence of concentrated arc discharge in the contact coating layer is recognized. May be When the variation in the contact resistance of the enclosed contact material increases, not only the contact resistance tends to fluctuate during the opening / closing operation of the enclosed contact, but also the amount of heat generated by the enclosed contact increases. as a result,
The operating life of the enclosed contact is shortened, and the variation of the operating life itself is increased, resulting in deterioration of reliability in actual use.

It is considered that such a problem is because the contact coating layer made of Mo, W or an alloy thereof does not have sufficient wear resistance and deteriorates the arc characteristics. Furthermore, Mo, W or their alloys are all
It is considered that this is because it is easily oxidized in the atmosphere and an electrically insulating oxide film is easily formed on the surface. That is, in the case of this material, the oxide film may already be formed on the surface of the contact coating layer (Mo or W) at the time of handling in air in the previous step of sealing it in the enclosure. Because. Also, when the surface of the glass sealing portion at the end of the contact base material is oxidized prior to the encapsulation, the contact coating layer may also be oxidized at the same time to form an oxide film on the surface.

When such an oxide film is observed under a microscope, it is an oxide film in a state where oxide particles are distributed on the surface of the contact coating layer. When the opening / closing operation of the encapsulated contact in which the encapsulated contact material whose surface is in such a state is encapsulated is repeated, the above-mentioned oxide particles are in actual contact with each other in a microscopic sense, that is, the contact coating. The phenomenon of dispersion, movement and concentration at the mutual contact parts of the layers is observed. From this, it is considered that in the case of a material in which an oxide film is formed in the contact coating layer, the above-mentioned deterioration of operating life characteristics is caused.

[0008] By the way, the enclosed contact is normally opened and closed while a voltage (current) is applied. However, normally, when an electric product is used, a disconnection or the like may occur on the load side. In that case, the opening / closing operation of the enclosed contact proceeds in the state where no voltage (current) is applied. For example, when the light emitting diode and the encapsulated contact are connected, even if the light emitting diode is disconnected due to the life of the light emitting diode, the encapsulated contact repeats the opening / closing operation in the unloaded state.

In particular, in the case of a reed switch, there is a great possibility that the enclosed contact of the reed switch is forced to open and close in the unloaded state by the activation of the switch opening and closing magnet. In the case where the contact coating layer is an encapsulated contact in which the encapsulated contact material made of Mo, W or an alloy thereof is encapsulated, the contact resistance rises when the above-mentioned opening / closing operation in the no-load state is repeated and the stability as a switch becomes stable. There is a problem of poor reliability and reliability. In particular, when the oxide film is formed on the surface of the contact coating layer of the encapsulated contact material, the above-mentioned problem is likely to occur.

In order to solve the above-mentioned problems in the encapsulated contact material in which the contact coating layer is formed of W, Mo or an alloy thereof, the present inventors have made the surface of the contact base material M
o, W, Re, Nb or Ta as a main component is coated to form a contact coating layer, and further Ru, Rh, P
We have developed an encapsulating contact material having a non-oxidizing conductive thin layer made of a material such as d, Os, Ir, Pt, Ag, Au, and have already filed it as Japanese Patent Application No. 4-19885.

In the case of this encapsulated contact material, since a non-oxidizing conductive thin layer is formed on the surface of the contact coating layer, the problem of the formation of an oxide film that has occurred when encapsulating in the encapsulation container is unlikely to occur. Become. Therefore, this encapsulated contact material has a small variation in initial contact resistance. However,
Although this encapsulated contact material has a small variation in initial contact resistance, welding resistance and arc resistance are not necessarily satisfactory from the request of further extending the operating life after initial operation, and therefore the above-mentioned characteristics Was required to be further improved. The present inventors have proposed Mo, Zr, N
At least one refractory metal selected from the group consisting of b, Hf, Ta, W is used as a matrix, and Li, K, C
e, Cs, Ba, Sr, Ca, Na, Y, La, Sc,
An encapsulated contact material in which a contact coating layer is formed by coating the surface of a contact substrate with a material containing at least one selected from the group consisting of Th and Rb, or a material containing an oxide thereof, and
In addition to the contact coating layer, Mg, Pb, Sn, Zn, B
i, Ag, Cd, Al, Si, Zr, Ti, Co, T
We have developed an encapsulated contact material made by adding a small amount of a, Fe, Mn, Cr, etc., and have already applied for it as Japanese Patent Application No. 6-39114.

In the case of this encapsulated contact material, Li, K, Ce, C contained in the above matrix of the contact coating layer.
s, Ba, Sr, Ca, Na, Y, La, Sc, Th,
All of Rb and the like are elements having a small work function, and in the contact coating layer containing these, arc generation during opening / closing operation of the enclosed contact becomes macroscopically uniform, and as a result, the contact base material located below Exposure is delayed. That is, the operating life is extended.

On the other hand, on the other hand, microscopically,
The arc causes minute irregularities to be formed on the entire surface of the contact coating layer.Therefore, the minute irregularities change the contact area between the contact coating layers, or they mesh with each other and cause defective opening and closing. May occur, resulting in a shortened operating life.

Mg, Pb, Sn, Zn, Bi, A
g, Cd, Al, Si, Zr, Ti, Co, Ta, F
In the case of the contact coating layer that further contains a trace amount of e, Mn, Cr, etc., these trace components are Li, K, Ce, C.
s, Ba, Sr, Ca, Na, Y, La, Sc, Th,
Although alloying with additional elements such as Rb to suppress the evaporation of these additional elements, the operational effect of reducing the variation in contact resistance during opening and closing operations is secured, the operating life characteristics are It cannot be expected that the material will be remarkably improved as compared with the material not containing. Moreover, in the case of the encapsulated contact incorporating the encapsulated contact material having the contact coating layer containing these trace components, the problem that the operating life of the manufactured encapsulated contact varies widely among lots, that is, the quality stability There is a problem that it is not good.

[0015]

DISCLOSURE OF THE INVENTION The present invention provides an encapsulated contact material which has more excellent operating life characteristics and a smaller variation in contact resistance than the encapsulated contact material of Japanese Patent Application No. 6-39114 mentioned above. With the goal. Further, the present invention provides an encapsulated contact material in which variations in characteristics between manufacturing lots are small, and thus operating life characteristics are stable,
Moreover, since the amount of expensive materials such as Rh and Ru used is suppressed as much as possible, it is an object of the present invention to provide an encapsulated contact material whose manufacturing cost is low.

A further object of the present invention is to provide a method for producing an encapsulated contact material in which the composition, surface shape, and texture of the contact coating layer are stable and the operating life characteristics are stabilized. In addition, the present invention, even when, for example, an oxide film is formed on the surface of the contact coating layer of the encapsulated contact material, or even when the opening / closing operation in the no-load state is repeated, the contact resistance is not deteriorated. An object of the present invention is to provide a method of manufacturing and using a sealed contact that does not occur.

[0017]

In order to achieve the above object, in the present invention, the surface of the contact base material is Mo,
At least one selected from the group of Zr, Nb, Hf, Ta, W is used as a substantial matrix, and Zn, Cd, Hg, Al, Ga, In, Tl, G is added to the matrix.
e, Sn, Pb, As, Sb, Bi of at least one selected from the group of 0.5 to 50 atom% and at least one layer of contact layer having a thickness of 0.1 μm or more Encapsulated contact material characterized by being covered with a coating layer (hereinafter referred to as contact material A); the surface of the contact base material is a matrix of at least one selected from the group of Mo, Zr, Nb, Hf, and W. And in the matrix,
Zn, Cd, Hg, Al, Ga, In, Tl, Ge, S
At least 1 which is made of a material containing 0.1 to 50 mol% of an oxide of at least one element selected from the group consisting of n, Pb, As, Sb and Bi, and has a thickness of 0.1 μm or more. Encapsulated contact material (hereinafter referred to as contact material B) characterized by being covered with a contact coating layer of a layer; and the surface of the contact base material is Mo, Zr, Nb, Hf, T.
a lower layer of at least one layer selected from the group consisting of a and W, and Zn, Cd, Hg, Al, Ga, I
n, Tl, Ge, Sn, Pb, As, Sb, Bi and at least one layer of at least one layer selected from the group consisting of at least one layer, and the thickness of the lower layer and the upper layer are both Provided is an encapsulated contact material (hereinafter referred to as contact material C), which is coated with at least one contact coating layer having a thickness of 0.1 μm or more.

Further, in the present invention, a contact coating layer of the contact material A or B is formed on the surface of the contact base material while controlling the temperature of the contact base material at 300 to 900 ° C. And a contact coating layer of the contact material C is formed on the surface of the contact base material while controlling the temperature of the contact base material when forming the lower layer at 300 to 600 ° C. The temperature of the contact base material is 50 to 6 as the upper layer.
A method for producing an encapsulated contact material, which comprises depositing a film while controlling the temperature at 00 ° C.

Further, according to the present invention, a method of manufacturing an encapsulated contact, which comprises discharging the encapsulated contact material after encapsulating the encapsulated contact material in an enclosure with an inert gas;
And a method of using an encapsulated contact, wherein the encapsulated contact material is discharged prior to or during use of the encapsulated contact, which is encapsulated in an airtight container together with an inert gas. It

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION First, the contact material A will be described. In this contact material A, as shown in FIG. 1, the surface of the contact base material 1 is coated to form a contact coating layer 2A described later. Here, the material of the contact base material 1 is not particularly limited, and may be any material conventionally used as a base material of an encapsulated contact, and considering the reduction of manufacturing cost, for example, , Fe, Ni, Co,
Ni-Fe, Co-Fe-Nb, Co-Fe-V, Fe
-Ni-Ni-Al-Ti, Fe-Co-Ni, carbon steel, phosphor bronze, nickel silver, brass, stainless steel, Cu-Ni
-Sn, Cu-Ti, etc. can be used.

The contact coating layer 2A is made of Mo, Zr, Nb, H.
At least one selected from the group consisting of f, Ta, and W, for example, simple substances of these metals, Hf-Nb, Hf-Ta, and H.
f-Mo, Hf-Zr, Hf-W, Mo-Nb, Mo-
Ta, Mo-Zr, MW, Nb-Ta, Nb-W, N
An alloy such as b-Zr, Ta-W, Ta-Zr, W-Zr is used as a matrix (hereinafter referred to as matrix metal), and Zn, Cd, Hg,
Al, Ga, In, Tl, Ge, Sn, Pb, As, S
It is composed of a material containing at least one element selected from the group of b and Bi as an additional element. Hereinafter, these elements are referred to as additive elements.

Each of the above-mentioned matrix metals forming the matrix of the contact coating layer 2A has a high melting point and a high hardness, and therefore serves to enhance the wear resistance of the contact coating layer. The additive element contained in this matrix stabilizes the contact resistance of the contact coating layer during the opening / closing operation, and contributes to the improvement of wear resistance and oxidation resistance.
Although this is not always clear, it is considered to be based on the following reasons.

That is, since the above-mentioned additional elements have a low melting point and a low boiling point as compared with the matrix metal, these additional elements are added from the inside of the matrix to the contact coating layer 2A due to, for example, an electric power load accompanying the opening / closing operation of the enclosed contact. It floats toward the surface and "bleeds" on the surface of the contact coating layer 2A.
It is considered that the above-mentioned added elements contribute to stabilization of contact resistance and stabilization of arc characteristics.

Further, even when oxygen in the atmosphere is taken in from the surface of the contact coating layer during formation of the contact coating layer or manufacture of the encapsulated contact, the taken oxygen is, for example, due to the above-mentioned additive element. It is considered to be adsorbed. That is, it is considered that oxygen is trapped by the additional element, so that the oxidation of the matrix metal of the contact coating layer is suppressed and an insulating oxide film is less likely to be formed on the surface thereof.

Therefore, the problem of destabilization of the contact resistance when an oxide film is formed on the surface of the contact coating layer is unlikely to occur, and the occurrence of the rocking phenomenon is reduced by stabilizing the arc characteristics described above. As a result, it is considered that the improvement of operating life characteristics is realized. From this point of view, in the contact coating layer 2A, in order to effectively exhibit the function of the additional element, the additional element forms an intermetallic compound with the matrix metal at the time of forming the contact coating layer described later. It is preferably in the state of being dispersed as a simple substance in the matrix metal without being generated.

Examples of the combination of the matrix metal and the additional element forming the contact coating layer 2A are Mo-Bi, Mo-Cd, Mo-Hg and Mo-I.
n, Mo-Pb; Nb-Bi, Nb-Hg, Nb-P
b; Ta-Bi, Ta-Hg, W-Bi, W-Cd, W
-Ga, W-Hg, W-In, W-Pb, W-Sb, W
-Sn, W-Zn; and the like can be mentioned as a suitable combination.

The content of the additional element in the contact coating layer 2A is set to 0.5 to 50 atom%. This content is 0.
If it is less than 5 atom%, the above-mentioned effect of the additional element is not sufficiently exhibited, and the contact resistance tends to become unstable during opening and closing operation. The electric resistance of the layer 2A is increased, causing a decrease in conductivity. The preferred content is 5
30 atomic%, particularly preferably 10 to 20 atomic%.
Is.

The contact coating layer 2A has a thickness of 0.1 μm.
It is set to m or more. This is because if the thickness is less than 0.1 μm, the contact coating layer has poor wear resistance, and satisfactory operating life characteristics as a sealed contact cannot be obtained. The upper limit of the thickness of the contact coating layer 2A is appropriately determined in view of the intended use condition of the encapsulated contact and the manufacturing cost. However, for example, when the film is formed by the film forming method described later, the thickness is not so much. When the thickness is increased, the surface of the contact coating layer is likely to be rough, which easily causes an increase in contact resistance and an increase in film formation cost. Therefore, the upper limit of the thickness of the contact coating layer 2A is preferably 100 μm.

In the contact coating layer 2A, the above-mentioned additional element may be uniformly contained in the matrix metal, or a concentration gradient of the additional element may be formed in the thickness direction. When the concentration gradient of the additional element is formed in the thickness direction, the concentration of the additional element is made higher toward the surface layer side of the contact coating layer 2A. Conversely, the matrix metal should have a higher concentration on the contact base material side.

When such a concentration gradient is formed in the contact coating layer, first, since a large amount of high melting point and high hardness matrix metal is present in the contact base material 1, the strength as an encapsulated contact material. The characteristics are improved and the structure of the contact coating layer is easily secured. Since the surface layer side has a high concentration of the additive element that exhibits the above-mentioned effect, even if the contact coating layer 2A comes into contact with oxygen and takes in it, for example,
Immediately captures the oxygen and suppresses the oxidation of the matrix metal itself and the progress of the oxidation reaction to the inside, which makes it difficult for an oxide film to be formed on the surface of the contact coating layer, and thus the opening / closing operation. This is because the contact resistance can be stabilized more preferably.

Although such a concentration gradient may be linear, a stepwise concentration gradient is easier to form considering that it is formed by a film forming method described later. For example, the matrix metal is 51 to 10 in the contact coating layer on the contact base material side.
It may be 0 atomic% (additional element is 0 to 49 atomic%), and 0 to 49 atomic% (additive element is 51 to 100 atomic%) in the surface layer side portion.

Even when the above-mentioned concentration gradient of the additional element is formed in the contact coating layer 2A, the content of the additional element must be set to 0.5 to 50 atomic% as an average value. I have to. Further, when the contact coating layer 2A having the above-mentioned composition further contains oxygen in an amount of 1 to 40 atomic%, the mechanism is not clear, but the arcs generated during the opening / closing operation of the enclosed contact are made uniform and uniform. It is preferable because it is promoted. In this case, if the oxygen content is less than 1 atomic%, the above effect becomes poor, and
If it is more than 0 atom%, the electric resistance of the contact coating layer 2A becomes high, and the conductivity is lowered, which is not preferable.

The contact coating layer 2A may be a single layer, but may have a laminated structure formed by laminating a plurality of layers. The reason for this is that in the case of various film-forming methods that are widely adopted at present, pinholes inevitably occur in the formed layer, but at that time, it is better to make the layer thinner to some extent. This is because the number of pinholes generated in the layer is reduced. That is, the contact coating layer 2A is formed by laminating a plurality of thin layers.
This is because, by forming the above, the total number of pinholes can be reduced and the contact characteristics can be improved.

In the case of the contact coating layer having this laminated structure, the layers overlapping each other may be made of the same material or different materials. In the latter case, the characteristics of each layer can be made to function in a mutually complementary manner, which is preferable. In the encapsulated contact material A, an intermediate layer may be interposed between the contact base material 1 and the contact coating layer 2A in order to enhance the adhesion therebetween. The material for the intermediate layer is A
Examples thereof include g, Al, Au, and alloys thereof. These are preferable in that they have good conductivity and are soft.

In the encapsulated contact material A, when the outermost layer is formed by coating the surface of the contact coating layer 2A with a material having a conductive metal or / and an oxide as a main component, the initial contact of the encapsulated contact obtained. This is preferable because the variation in resistance can be reduced. As the metal at this time, for example, R
u, Rh, Re, Pd, Os, Ir, Pt, Ag, Au
Any one of, for example, Ag-Au, Ag-Pd,
Ag-Pt, Ag-Rh, Au-Pd, Au-Pt, A
u-Rh, Ir-Os, Ir-Pt, Ir-Ru, Os
-Pd, Os-Ru, Pd-Pt, Pd-Rh, Rd-
One or more of Ru, Pt-Rh, Re-Rh, Re-Ru and the like can be mentioned. Examples of the oxide include RuO ₂ , Rh ₂ O ₃ , RhO ₂ and ReO.
₁ , OsO ₄ , IrO ₂ , Ir ₂ O ₃ , etc., or 2
You can give more than one seed.

The thickness of this uppermost layer is preferably 0.05 μm or more. This is because when the thickness is less than 0.05 μm, the above-mentioned effects are not sufficiently exhibited. The upper limit of the thickness is not particularly limited, but may be appropriately set in consideration of the mutual interval and size of the encapsulated contact material when encapsulated in the encapsulation container and the film formation cost. Roughly 2
The upper limit is 0 μm.

Next, the contact material B of the present invention will be described. In the case of this contact material B, as shown in FIG.
The contact coating layer 2B is formed by adding Z to the matrix metal described above.
n, Cd, Hg, Al, Ga, In, Tl, Ge, S
The contact material A is the same as the contact material A except that it contains an oxide of at least one element selected from the group consisting of n, Pb, As, Sb, and Bi.

Also in this case, the oxide stabilizes the contact resistance during the opening and closing operation and wear resistance of the contact coating layer 2B, as in the case where the above elements are dispersed alone in the matrix metal. ， It increases the oxidation resistance and suppresses the occurrence of rocking phenomenon, which contributes to the improvement of operating life characteristics. In this contact material B, the oxide content is 0.1 to 50.
Set to mol%. When it is less than 0.1 mol%, the contact resistance becomes unstable and the above-mentioned effect is difficult to be exhibited, and when it is more than 50 mol%, the electric resistance of the contact coating layer 2B becomes high and the conductivity is lowered. It is caused.

The thickness of the contact coating layer 2B depends on the contact material A
For the same reason as above, it is necessary to set the thickness to 0.1 μm or more, and the upper limit of the thickness is preferably 100 μm for the same reason. Furthermore, in this contact coating layer 2B,
As in the case of the contact material A, if oxygen is further contained in an amount of 1 to 40 atomic%, the arc generated during the opening / closing operation of the contact is promoted to be uniform and uniform, so that the operating life characteristics are improved. Is suitable. The oxygen content at this time is preferably set in the above range for the same reason as in the case of the contact material A.

The contact coating layer 2B is made of the contact material A.
For the same reason as above, a laminated structure of a plurality of layers may be used. Then, as in the case of the contact material A,
An intermediate layer having the same material and thickness as described above may be interposed between the contact coating layer 2B and the contact base material 1,
Further, the contact coating layer 2B may be coated to form an uppermost layer having the same material and thickness as those described above.

Next, the contact material C of the present invention will be described. In the case of this contact material C, as shown in FIG. 3, the contact coating layer 2C formed by coating the surface of the contact base material 1 is
A lower layer 2C ₁ composed of at least one selected from the group consisting of Mo, Zr, Nb, Hf, Ta and W, and Zn, Cd, Hg, Al, Ga, In, Ti,
The upper layer 2C ₂ is made of at least one selected from the group consisting of Ge, Sn, Pb, As, Sb and Bi, and has a laminated structure as a whole.

The contact coating layer 2C has, as a basic unit, a laminated structure of the lower layer 2C ₁ and the upper layer 2C ₂ described above.
It may have only a layer, or may have a structure in which a plurality of the basic units are laminated by an integral multiple. In the case of this contact coating layer 2C, the lower layer 2C made of a metal that is easily oxidized
_Since the surface of ₁ is covered with the upper layer 2C ₂ made of an element having a property of trapping oxygen as described above, the contact coating layer 2C comes into contact with oxygen at the time of handling in the air or at the time of manufacturing a sealed contact. Even so, oxygen is trapped in the upper layer 2C ₂ and oxidation of the lower layer 2C ₁ is suppressed, and thus formation of an oxide film that induces variation in contact resistance during opening / closing operation is suppressed. Therefore, the operating life characteristics are improved as compared with the case of the contact material A described above.

Here, each of the lower layer 2C ₁ and the upper layer 2C ₂ may have a single-layer structure. However, as described above, each of them has a plurality of pinholes because the occurrence of pinholes is reduced. It may have a laminated structure formed by laminating thin layers. In that case, each thin layer in the lower layer 2C ₁ and the upper layer 2C ₂ may be formed of the same material or different materials. In the latter case, the characteristics of each thin layer can be made to function complementarily to each other, which is preferable.

The thickness of each of the lower layer 2C ₁ and the upper layer 2C ₂ is set to 0.1 μm or more. The reason is based on the same reason as the reason explained about the thickness of the contact coating layers 2A and 2B of the contact materials A and B. In addition, contact materials A and B
In the same manner as in the above case, a similar intermediate layer may be interposed between the contact base material 1 and the lower layer 2C _1, and further, the upper layer 2
A similar top layer may be formed on the surface of C ₂ .

Thus, the encapsulated contact material A of the present invention,
Oxidation of the surface of the contact coating layer of B and C is suppressed by the action of the above-mentioned additional elements and oxides thereof, so that the contact resistance is small and the variation thereof is small, and the operating life characteristics of the encapsulated contact are improved. In addition, W, Zr, Nb, Ta, and M, which have not been used effectively in the conventional encapsulated contacts,
Since, for example, o can be used and the amount of expensive Rh, Ru, etc. used can be reduced, an inexpensive encapsulated contact material can be obtained.

Next, a method of manufacturing each contact material A, B, C will be described. Any of these contact materials A, B, C can be manufactured by forming the above-mentioned contact coating layers 2A, 2B, 2C on the surface of the contact base material by a conventional film forming method. That is, first, for example, Ar, N
The surface of the contact base material is cleaned by ion bombardment or electron shower using rare gas ions such as e and Kr, and then, for example, sputtering method, ion assisted vapor deposition method, ion plating method, plasma CVD method, etc. A predetermined contact coating layer is formed on the cleaned surface of the contact base material by a conventional physical vapor deposition method or chemical vapor deposition method.

An important problem in forming this contact coating layer is
To properly control the temperature of the contact base material, more strictly speaking, the surface temperature of the contact base material. Generally, if the surface temperature of the contact base material is too low, the crystallization of the contact coating layer formed on the contact base material will be insufficient, or a porous columnar structure will be formed, resulting in corrosion resistance of the contact coating layer. Will decrease, and diffusion of constituents will occur. On the contrary, when the surface temperature is too high, the formed contact coating layer has a rough columnar structure, and the surface roughness is increased, which causes increase in contact resistance and destabilization. From the above, in the present invention, when the contact coating layer is formed on the surface of the contact base material,
The temperature of the contact base material is controlled at 300 to 900 ° C. Preferably 400-800 ° C, more preferably 300-600
° C.

By the way, in the present invention, among the components constituting the contact coating layers 2A, 2B and 2C, Mo, Zr,
Nb, Hf, Ta, W or alloys thereof all have high melting points and high boiling points, while Zn, Cd, Hg, A
1, Ga, In, Tl, Ge, Sn, Pb, As, S
Additive elements such as b and Bi have relatively low melting points and boiling points.

Therefore, when a contact coating layer having a composition or a laminated structure composed of the above components is formed on the surface of the contact base material, depending on the temperature of the contact base material, the addition element having a relatively low melting point and a low boiling point may be added. Re-evaporation may occur. When such a situation occurs, the composition of the contact coating layer changes, and it becomes impossible to impart desired characteristics to the contact coating material to be manufactured in a stable state.

Therefore, in the present invention, the contact coating layer 2
When forming A, 2B, and 2C, the temperature of the contact base material is controlled as follows. First, when manufacturing the contact materials A and B, the temperature of the contact base material is controlled to 300 to 900 ° C.
When the temperature is lower than 300 ° C, as described above, the contact coating layers 2A and 2B are insufficiently crystallized or have a porous columnar structure. This is because evaporation easily occurs and the composition of the contact coating layers 2A and 2B fluctuates, which causes a difficulty in manufacturing a stable quality encapsulated contact material. Preferably 400 to 800 ° C., particularly preferably 300 to 6
Control at 00 ° C.

When it is desired to make the contact coating layers 2A and 2B contain 1 to 40 atomic% of oxygen in the contact materials A and B, the oxygen partial pressure in the atmosphere of the reaction system is set at the time of the above film formation. The contact coating layers 2A and 2B may be formed in an appropriately controlled state. After forming the contact coating layers 2A and 2B, heating may be performed in an oxygen-containing atmosphere such as air.

Even in the latter case, the electrically insulating oxide film is not excessively formed on the surfaces of the contact coating layers 2A and 2B. It is considered that this is because most of the oxygen is captured by the additional element and the residual oxygen diffuses into the inside of the contact coating layer. The atmosphere and temperature during this heat treatment may be set appropriately. For example, in the atmosphere, the temperature is 100
The heat treatment may be performed at about 400 ° C. for about 5 to 36 hours. This is because if the temperature is higher than 400 ° C., the oxidation tends to proceed excessively, and if it is lower than 100 ° C., the treatment time becomes long and it is industrially disadvantageous.

The above-mentioned intermediate layer and uppermost layer can be formed by the above-mentioned film forming method which is commonly used for forming a contact coating method. Next, when forming the contact coating layer 2C of the contact material C, first, the temperature of the contact base material is set to 300 to 9 ° C.
The lower layer 2C ₁ is formed on the surface of the surface under the control of 00 ° C. When the temperature at this time becomes lower than 300 ° C, the lower layer 2
If C ₁ has insufficient crystallization, or has a porous columnar structure, the corrosion resistance is deteriorated, and further, diffusion of constituent components may occur. The reason is that a coarse columnar structure is formed and the surface roughness is increased, which causes an increase in contact resistance and destabilization.

Next, when forming the upper layer 2C ₂ on the lower layer 2C ₁ , the temperature of the contact base material, that is, the total temperature of the contact base material and the lower layer 2C ₁ formed thereon is 50 to 500. Controlled to ℃. When this temperature is lower than 50 ° C., the adhesiveness with the lower layer 2C ₁ becomes extremely poor and peeling of the upper layer 2C ₂ film occurs, and conversely 500 ° C.
This is because if it becomes higher, re-evaporation of the formed upper layer 2C ₂ begins to occur.

Next, a method of manufacturing and using the encapsulated contact of the present invention will be described. This method can be applied to the case where the encapsulated contact material is the contact material A, B or C of the present invention described above, but is particularly applied to a contact material whose contact coating layer is made of a material which is easily oxidized. It is valid. First, the manufacturing method will be described.

A predetermined sealed contact material is sealed in a sealed container together with an inert gas into a sealed contact by a conventional method, and then the sealed contact material is discharged. This discharge method is not particularly limited, but it can be applied to both electrodes of the enclosed contact material.
It is preferable to apply a voltage of 00 to 3000 V and discharge for 1 to 100 seconds. If such measures are taken, an increase in contact resistance during opening / closing operation and its variation are suppressed, and an improvement in operating life characteristics is recognized.Also, even if this enclosed contact is opened / closed, no contact resistance is applied. Is less likely to deteriorate.

Although the grounds for the above-mentioned phenomenon are not clear, the fine particles of the oxide forming the oxide film formed on the surface of the contact coating layer at the time of manufacturing the encapsulated contact cause the contact material to contact with the contact material during the process of opening and closing. It is considered that this is because the phenomenon in which they concentrate at the actual contact portions of each other is suppressed, or the oxide fine particles are evaporated by the high heat generated by the discharge and the oxide film of the contact coating layer is removed.

Next, a method of using the encapsulated contact of the present invention will be described. In this method, the encapsulated contact material is discharged in the same manner as described above before using the manufactured encapsulated contact. By performing such a treatment, even if an oxide film is formed on the contact coating layer of the encapsulated contact material, the adverse effect of the oxide film on the operating life characteristics is eliminated for the same reason as described above. Become.

Further, if the above-mentioned discharge treatment is carried out in the middle of the use even for the enclosed contact after being used,
It goes without saying that the improvement of the operating life characteristics can be realized for the same reason. As described above, by applying the above-described manufacturing method and usage method to the encapsulated contact, even if an oxide film is formed on the contact coating layer of the encapsulated contact material to be encapsulated, it is possible to remove the oxide film. It is possible to exhibit excellent operating life characteristics of the enclosed contact.

[0060]

【Example】

Examples 1 to 16 and Comparative Examples 1 to 5 The contact material A shown in FIG. 1 was manufactured as follows. First, a plate made of 52% Ni-Fe alloy and having a length of 1 mm and a width of 1 mm was prepared as a contact base material for a lead pin. The surface of this contact base material was ultrasonically cleaned with acetone for 5 minutes, and further phosphoric acid electrolytic polishing was performed to clean the surface.

Then, the contact base material was set in the chamber of the vacuum vapor deposition apparatus, the chamber was evacuated to 2 × 10 ^-4 Pa or less, and then the valve of the vacuum pump was half-opened to reduce the exhaust conductance. , 1 × 1 in the chamber
Ar gas was introduced until it reached 0 ⁻¹ Pa. Then, a voltage of −400 V was applied to the contact base material, a high frequency of 0.2 kW was generated from a high frequency antenna in the chamber, and ion bombardment treatment was performed with Ar ions to clean the surface.

The contact base material 1 was maintained at the temperatures shown in Table 1,
Each element shown in Table 1 was evaporated from the electron beam evaporation source set in the chamber, and the deposition rate was 20Å / sec.
A contact coating layer 2A having the composition and thickness shown in Table 1 was formed. The characteristics of each obtained contact material were examined according to the following specifications. Contact resistance: Contact material immediately after production and N _{2 at a} temperature of 430 ° C.
After leaving it in the atmosphere for 30 minutes and then cooling it to room temperature, contact the probe made of pure Au with a contact load of 0.1 N to the area of 1 mm x 1 mm, and contact resistance (mΩ) at that time. Is measured by the 4-terminal method. The measurement was performed in the air at room temperature.

Life test: N ₂ using a pair of contact materials
A reed switch with a sealed gas of was produced. At room temperature, a current of 100V, 0.5A is applied to this reed switch, and the drive magnetic field of 40AT (ampare turn) causes 1
The opening / closing operation was performed at 0 Hz, and the number of opening / closing operations up to the occurrence of a failure was examined. In addition, the time of occurrence of a failure means a time when a failure in opening and closing appears or a time when the resistance value between both electrodes of the reed switch becomes 1Ω or more.

The above results are collectively shown in Table 1.

[0065]

[Table 1]

For the reed switch incorporating the contact material of Example 2 and the reed switch incorporating the contact material of Comparative Example 1, the relationship between the number of opening / closing operations and the resistance value between both electrodes was examined. FIG. 4 shows the results. For reference, the relationship between the number of opening / closing operations and the resistance value between both electrodes of a reed switch incorporating a contact material having a contact coating layer made of Rh is also shown in FIG.

In FIG. 4, the Δ mark (and ▲ mark) is a reed switch incorporating the material of Example 2, and the ○ mark (and ● mark).
Indicates the case of a reed switch incorporating the material of Comparative Example 1, and the square marks (and ■) indicate the case of the reed switch incorporating the material of the reference example. The black ▲ mark, ● mark, and ■ mark indicate the time points when the opening / closing failure appears. As is clear from the results shown in Table 1, the contact materials of the present invention were both immediately after production and heat treatment, as compared with the contact materials having the contact coating layer containing no additional element (Comparative Examples 1 and 2). In any of the latter cases, the contact resistance is small and the operating life characteristics are much improved.

Even when the additive element is contained, if the content is less than 1 atom% and more than 50 atom% (Comparative Examples 3 and 4), the contact resistance is high in all cases. The operating life is short. Therefore, the content of the additional element should be 1 to 50 atomic%. Furthermore, when the thickness of the contact coating layer is 0.01 μm,
The operating life is extremely short. Therefore, the thickness of the contact coating layer should be 0.1 μm or more.

As is apparent from FIG. 4, the resistance value of the reed switch incorporating the contact material of the present invention (Example 2) is the same as that of the contact material of Comparative Example 1 or the reference material of Reference Example. Compared with the resistance value between the two electrodes, the variation is small and stable. That is, the contact material of the present invention is a contact-stable material. In addition, the operating life is significantly longer than that of the reference example (Rh coating).

Examples 17 to 24, Comparative Examples 6 and 7 The temperature of the contact base material was maintained at 700 ° C., the oxygen partial pressure in the chamber was adjusted, and the composition shown in Table 2 was obtained at a deposition rate of 20 Å / sec. A thick contact coating layer was deposited on the contact substrate. For each contact material obtained, contact resistance and operating life characteristics were measured in the same manner as in Examples 1-16. The above results are collectively shown in Table 2.

[0071]

[Table 2]

In the table, the contact coating layers of Examples 17, 18, and 19 and Comparative Examples 6 and 7 are all obtained by adding oxygen to the contact coating layer of Example 2 shown in Table 1. As is clear from comparison between Example 2 and these, it can be seen that when the contact coating layer contains oxygen, the contact resistance is slightly increased, but the operating life characteristics are further improved.
However, when the oxygen content is more than 40 atom%, the contact resistance becomes high and at the same time, the operating life characteristics also deteriorate (Comparative Example 7). In addition, Comparative Example 6 exhibits substantially the same characteristics as Example 2. This means that the oxygen content is 1 atomic%
When the amount is less than the above, the effect of containing oxygen is poor.

Examples 25 to 40, Comparative Examples 8 to 10 A contact coating layer having the composition and thickness shown in Table 3 was formed,
Next, the temperature of the contact base material is lowered to 300 ° C., and the indicated element is evaporated from the electron beam evaporation source while maintaining the temperature, and the metal layer of the indicated thickness is used as the uppermost layer on the contact coating layer. Formed.

For each of the obtained contact materials, Examples 1 to 1
The contact resistance and operating life were measured in the same manner as in 6. The above results are collectively shown in Table 3.

[0075]

[Table 3]

In the table, the contact coating layers of Examples 25 to 30 and Comparative Example 8 correspond to the contact coating layer of Example 2 shown in Table 1 in which the outermost layer is formed. As is clear from comparing these, when the outermost layer is further formed, the operating life is further extended as compared with the case of the second embodiment. However, when the thickness becomes thin (Comparative Examples 8 to 10), the effect of improving the operating life cannot be expected, and it is understood that the thickness of the uppermost layer is preferably 0.05 μm or more.

Examples 41 to 52, Comparative Examples 11 and 12 The contact base materials used in Examples 1 to 16 were set in a chamber of a vacuum vapor deposition apparatus, and the inside of the chamber was set to an Ar atmosphere of 0.66 Pa. With the temperature maintained at 400 ° C, 0.5
A contact coating layer having the composition and thickness shown in Table 4 was formed by a kW DC magnetron sputtering method.

Then, oxygen is introduced into the chamber, the oxygen partial pressure at that time is adjusted, and the target is changed to form a metal oxide layer having the composition and thickness shown on the contact coating layer. It was formed as an upper layer. The contact resistance and operating life characteristics of each of the obtained contact materials were measured in the same manner as in Examples 1 to 16. The above results are collectively shown in Table 4.

[0079]

[Table 4]

As is clear from the comparison of the results shown in Tables 4 and 1, even when the outermost layer, which is a metal oxide layer, is formed on the surface of the contact coating layer, the operating life is extended. However, Comparative Example 11, in which the thickness of the outermost layer is as thin as 0.01 μm,
In the case of 12, the above effect is not so remarkable. Examples 53 to 56, Comparative Examples 13 and 14 The contact material of Example 2 was heated in the atmosphere at the temperature shown in Table 5 for the time indicated to perform surface oxidation. The contact resistance and operating life characteristics of the obtained heat-treated product were measured in the same manner as in Examples 1 to 16. The above results are collectively shown in Table 5.

[0081]

[Table 5]

As is clear from the results shown in Table 5, even if the contact coating layer was oxidized in the atmosphere, the results of Examples 41 to
Similar to the case of No. 52, the operating life characteristics are improved.
In that case, Comparative Example 13, whose oxidation temperature is as low as 70 ° C., is characteristically equivalent to Example 2, and the effect of the oxidation treatment is not exhibited. On the other hand, in the case of Comparative Example 14 in which the oxidation temperature is too high at 500 ° C., the contact resistance becomes too high and the operating life becomes short. Therefore, the temperature during the oxidation treatment in the atmosphere is preferably 100 to 400 ° C.

Examples 57 to 76, Comparative Examples 15 to 19 Using the same conditions as in Examples 1 to 16 except that the temperature of the contact base material was adjusted as shown in Table 6, FIG. The indicated contact material A was produced. For each 20 contact materials,
The contact resistance and operating life characteristics were measured in the same manner as in Examples 1 to 16. The results are collectively shown in Table 6. Regarding the operating life characteristics, the average value and standard deviation are shown.

[0084]

[Table 6]

As is clear from Table 6, in the case of the comparative example material formed by keeping the temperature of the contact base material at 200 ° C., the average number of opening / closing operations in its operating life is smaller than that of the example material. Moreover, the standard deviation value is extremely high, the life is varied, and it cannot be said that the material is highly reliable. When the contact coating layer of the comparative material after production was observed under a microscope, many of them were largely peeled off, and few of them completely covered the surface of the contact base material.

On the other hand, in the case of the materials of the examples, the temperature of the contact base material was maintained at 700 ° C.
Although the contact coating layer surely covered the surface of the contact base material as compared with the one having a temperature of 300 ° C., the holding temperature was 300 to 600 ° C. although the operating life characteristics were slightly superior to those of the comparative example material.
It is inferior to the material of the example. It is considered that this is because the temperature of the contact base material at the time of film formation is high, so that the additional element is re-evaporated and the content in the matrix metal varies.

From the above, it is understood that the temperature of the contact base material during film formation is preferably controlled to 300 to 600 ° C. Examples 77 to 96, Comparative Examples 20 to 24 With the contact base material maintained at the temperatures shown in Table 7, the chamber was set to an atmosphere of 0.66 Pa (Ar + O ₂ ) and a DC magnetron sputtering method of 0.5 kW was used. A contact coating layer having the composition and thickness shown in Table 7 was formed.

Regarding the obtained contact materials, Examples 57 to 7 were used.
In the same manner as in No. 6, the average number of opening / closing operations and the standard deviation of contact resistance and operating life characteristics were examined. The above results are collectively shown in Table 7.

[0089]

[Table 7]

As is clear from Table 7, when the contact coating layer contains oxygen, the operating life characteristics are slightly improved as compared with the materials of Examples 57 to 76. However, even in that case, if the temperature of the contact material during film formation is set to 200 ° C., the operating life characteristics deteriorate, so it is preferable to keep the temperature of the contact base material during film formation at 300 to 600 ° C. .

Examples 97 to 109, Comparative Examples 25 to 30 Table 2 shows the two electron beam evaporation sources mounted in the chamber of the vacuum vapor deposition apparatus used for manufacturing Examples 1 to 16, respectively. The matrix metal and the additional element were set, and the contact coating layer having the thickness shown below was formed in the state where the contact base material was maintained at the indicated temperature (400 ° C.).

That is, with respect to the evaporation of the matrix metal, the contact coating layer has a thickness of 100 at the contact base material side.
In the thickness direction of the contact coating layer, the contact coating layer is evaporated so that the concentration of the matrix metal becomes 0 atomic% on the surface of the contact coating layer. A concentration gradient was applied to. During this process, the deposition rate of the matrix metal was kept constant at 20Å / sec.

On the other hand, regarding the additive element, the concentration is set to 0 atom% on the contact base material side, and thereafter, the concentration is gradually increased.
A concentration gradient was applied to the surface of the contact coating layer so that the concentration would be 100 atomic%. The deposition rate at this time is also 20Å / sec
And made it constant. Therefore, the formed contact coating layer is
It has a composition in which an additive element is contained in a matrix metal. However, there is a concentration gradient of the additional element in the thickness direction. That is, the additive element is small on the contact base material side, and the additive element is large on the surface layer side.

This operation was used as a basic operation, and this operation was repeated to form a laminated structure of the contact coating layer. The number of the laminated structures is shown in Table 8. About the obtained contact material, Example 5
The contact resistance and operating life characteristics were measured in the same manner as in 7 to 76. The above results are collectively shown in Table 8.

[0095]

[Table 8]

As is clear from Table 8, even when the contact coating layer is provided with a concentration gradient of the additional element as described above,
The average number of operations increases, the standard deviation is small, and the operating life characteristics are excellent. However, Comparative Examples 25-3
As shown in Fig. 0, when the contact coating layer is thin, the operating life characteristics are deteriorated, so it is understood that the thickness should be 0.1 µm or more.

Examples 110 to 120, Comparative Examples 31 and 32 A matrix was formed in the same manner as in Examples 97 to 109 except that the temperature of the contact base material was changed as shown in Table 9. A contact coating layer having a concentration gradient of metal and additive element was formed. The contact resistance and operating life characteristics of the obtained contact material were measured in the same manner as in Examples 97 to 109. The above results are collectively shown in Table 9.

[0098]

[Table 9]

As is clear from Table 9, when the temperature of the contact base material reaches 200 ° C., the contact resistance increases and the operating life characteristics deteriorate. Also, the temperature of the contact base material is 700 ° C.
Then, the operating life characteristics tend to decrease. Therefore, it is preferable to control the temperature of the contact base material at 300 to 600 ° C. Examples 121 to 133, Comparative Examples 33 to 35 The contact material B shown in FIG. 2 was manufactured as follows.

The contact base material used in Examples 1 to 16 was set in the chamber of the vacuum vapor deposition apparatus, and the inside of the chamber was set to 0.66 Pa.
(Ar + O ₂ ) atmosphere and set the temperature of the contact base material to 400
The contact coating layer 2B having the composition and the thickness shown in Table 10 was formed by the RF magnetron sputtering method of 0.7 kW while maintaining the temperature at ℃. The contact resistance and operating life characteristics of each of the obtained contact materials were measured in the same manner as in Examples 1 to 16. The above results are collectively shown in Table 10.

[0101]

[Table 10]

As is clear from Table 10, even when the oxide of the additional element is contained in the matrix metal in the contact coating layer, the operating life characteristics are better than those of Comparative Examples 1 to 5 shown in Table 1. It has been improved to a superb level. However, as in Comparative Examples 33 and 34, when the oxide content is too small or too large, the contact resistance becomes high and the operating life characteristics also deteriorate. Therefore, the content of oxide in the matrix metal should be 1 to 50 mol%.

Further, the contact resistance of the contact material of the example is lower than that of the contact material of the comparative example both immediately after the production and after the heat treatment. Examples 134 to 145, Comparative Examples 36 and 37 A contact coating layer having the composition and thickness shown in Table 11 was formed on the surface of the contact base material in the same manner as in Examples 121 to 133, and then the target was changed. A metal layer having a thickness shown in Table 11 was formed as an uppermost layer on the contact coating layer by a DC magnetron sputtering method of 0.5 kW.

For each contact material obtained, Example 121
The contact resistance and operating life characteristics were measured in the same manner as for .about.133. The above results are collectively shown in Table 11.

[0105]

[Table 11]

Examples 146 to 155, Comparative Examples 38 and 39 A contact coating layer having the composition and thickness shown in Table 12 was formed on the surface of the contact base material in the same manner as in Examples 121 to 133. The target was changed, and a metal oxide layer having the composition and thickness shown in Table 12 was formed as the uppermost layer on the contact coating layer by a DC magnetron sputtering method of 0.5 kW.

For each contact material obtained, Example 121
The contact resistance and operating life characteristics were measured in the same manner as for .about.133. The above results are collectively shown in Table 12.

[0108]

[Table 12]

As is clear from Tables 11 and 12, even if a metal layer or an oxide coating layer is formed as the outermost layer on the surface of the contact coating layer, such treatment is performed as in Examples 121 to 133. The operating life is extended as compared with the case where it is not applied. However, if the thickness of the outermost layer is thin, the above-mentioned effect is not so remarkable. Examples 156 to 170, Comparative Examples 40 to 47 The contact material C shown in FIG. 3 was manufactured as follows.

The contact material was set in the vacuum vapor deposition apparatus used in Examples 1 to 16, and the contact base material was heated at the temperature (6
The lower layer 2C _{1 of the} indicated thickness made of the indicated metal is deposited from the electron beam evaporation source with the deposition rate of 20Å / s.
ec is used to form a film, and then the temperature of the contact base material is displayed (20
0 ° C.), further above the lower layer 2C ₁ ,
The upper layer 2C _{2 of the} indicated thickness composed of the indicated elements is deposited at a deposition rate of 2
A film was formed at 0Å / sec to form a laminated structure to form the contact coating layer 2C.

Regarding the obtained contact materials, Examples 1 to 16
The contact resistance and operating life characteristics were measured in the same manner as in.
The results are collectively shown in Table 13.

[0112]

[Table 13]

As is clear from Table 13, with such a laminated structure, the average number of operations is larger than that of the contact materials of Examples 1 to 16 shown in Table 1. But,
As is clear from comparison between the comparative example material and the example material in Table 13, 0.1 μ is obtained in either the lower layer 2C ₁ or the upper layer 2C _2.
If the thickness is less than m, the average number of operations decreases and the standard deviation increases, so the thickness should be 0.1 μm or more.

Examples 171-181, Comparative Examples 48-51 The contact base material was set in the vacuum vapor deposition apparatus used in Examples 1-16, and the contact base material was kept at the temperature shown in Table 14 with an electron beam. The indicated metal was evaporated from the evaporation source to form the lower layer 2C _{1 of the} indicated thickness at a deposition rate of 20 Å / sec, and then the contact base material was cooled to the indicated temperature and kept displayed at that temperature. Upper layer 2 of the indicated thickness by evaporating the elements
C ₂ was deposited at a deposition rate of 20Å / sec to form a laminated structure.

Regarding the obtained contact materials, Examples 1 to 16
The contact resistance and operating life characteristics were measured in the same manner as in.
The results are collectively shown in Table 14.

[0116]

[Table 14]

As is clear from Table 14, the contact resistance and the operating life characteristics of the contact material fluctuate greatly depending on the temperature of the contact base material during the upper layer film formation and the temperature of the contact base material during the lower layer film formation. There is. For example, regarding the temperature of the contact base material at the time of forming the upper layer, comparing Example 171 with Comparative Example 48, a temperature of 2
When the temperature is 00 ° C., the contact resistance is higher than that at the temperature of 400 ° C., and the operating life characteristics are deteriorated. The same applies to the case where the temperature is 900 ° C. (Comparative Example 49) and the case where the temperature is 800 ° C. (Example 172). Therefore, when forming the upper layer, the temperature of the contact base material should be 400 to
It turns out that the temperature should be controlled to 800 ° C.

Regarding the contact temperature at the time of forming the lower layer,
Comparing Example 173 with Comparative Example 50, the contact resistance at the temperature of 30 ° C. is higher than that at the temperature of 50 ° C.
The operating life characteristics are degraded. Further, when the temperature is 550 ° C. (Comparative Example 51) and when the temperature is 500 ° C. (Example 1)
The same applies to 74). Therefore, it is understood that the temperature of the contact base material should be controlled to 50 to 500 ° C. when forming the lower layer.

Examples 182 to 189, Comparative Examples 52 to 57 In the same manner as in Examples 1 to 16, the contact material was set in the vacuum vapor deposition apparatus and the contact base material was held at the indicated temperature (400 ° C.). Then, the same basic operation as in Examples 97 to 109 was performed to first form a lower layer having the indicated composition, thickness, and number of laminated structures on the contact base material, and then display the contact base material. The temperature was lowered to 200 ° C. and maintained at that temperature, and an upper layer of the indicated thickness composed of the indicated elements was formed on the lower layer. However, the deposition rate during upper layer deposition is 25Å
/ Sec.

Therefore, in the case of this contact coating layer, the lower layer is a layer having a concentration gradient of the additional element, and the upper layer has a laminated structure of layers made of the above additional element. The contact resistance and operating life characteristics of the obtained contact material were measured in the same manner as in Examples 1 to 16. The above results are collectively shown in Table 15.

[0121]

[Table 15]

As is apparent from Table 15, the contact material having such a structure also has excellent operating life characteristics. And as can be seen by comparing the example material and the comparative example material,
As the thickness of the upper layer becomes thinner, the average number of operations decreases, and the standard deviation also increases, resulting in a decrease in operating life characteristics. Therefore, the thickness of the upper layer should be 0.1 μm or more.

Examples 190 to 196, Comparative Examples 58 and 59 Except that the temperature of the contact base material at the time of forming the lower layer and the temperature of the contact base material at the time of forming the upper layer were changed as shown in Table 16. As a result, a contact coating layer was formed in the same manner as in Examples 182 to 189. For each contact material obtained, contact resistance and operating life characteristics were measured in the same manner as in Examples 182-189. The above results are collectively shown in Table 16.

[0124]

[Table 16]

As is clear from Table 16, in this case as well,
As in the case of Examples 171-181, by controlling the temperature of the contact base material to 300 to 600 ° C. during the upper layer film formation and controlling the temperature of the contact base material to 50 to 500 ° C. during the lower layer film formation. The contact resistance can be reduced, the average number of operations can be increased, and the standard deviation can be reduced.

Examples 197 to 220, Comparative Examples 60 to 67 First, various contact materials (lead pins) were manufactured by the method described in Examples 1 to 16. Microscopic observation of the surface of the contact coating layer in each of the obtained contact materials confirmed the presence of oxide particles having a size of several μm.

Next, each contact material was filled with N _{2 in an} enclosure.
It was sealed together with the gas to form an enclosed contact (reed switch). The obtained encapsulated contacts were subjected to discharge treatment under the conditions shown in Tables 17-18. In each of the comparative examples in the table, the discharge treatment is not performed. Then, the operating life characteristics of the enclosed contact were measured with the following specifications.

Life test under low load: While applying 5 V to the enclosed contact and passing a current of 100 μA, the opening / closing operation was repeated at 100 Hz by the driving magnetic field of 40 AT, and the number of operations until failure occurred was measured. High load life test: Examples 206-208, Example 21
Except 1 and other encapsulated contacts, at 100V at room temperature
Repeating the opening and closing operation at 10Hz by the driving magnetic field of 40AT while flowing the current of 0.5A, the number of operations until the failure occurs is measured.

In any of the life tests, the point of failure refers to the point of time when a switching failure occurs or the resistance value between the two poles of the enclosed contact becomes 1Ω or more. The above results are collectively shown in Tables 17 to 18.

[0130]

[Table 17]

[0131]

[Table 18]

The reed switch of Example 202 and the reed switch of Comparative Example 61 were operated in the same manner as in the low load life test described above, and the resistance between the two electrodes at that time was measured. The results are shown in FIG. 5 as the relationship between the number of operations and the resistance value. In the figure, ◯ indicates the case of the reed switch of Example 202, and □ indicates the case of the reed switch of Comparative Example 61.

As is clear from the results shown in Tables 17 to 18, the encapsulated contacts that were subjected to the discharge treatment as in the examples were
Its operating life is much longer than that of the sealed contact of the comparative example. In order for the operating life under high load to be stable, it is necessary that at least the operating life under low load be stable, but as is clear from FIG. 5, in the life test under low load, the example is a comparative example. The resistance value between the two poles is stable with respect to the number of times of operation. That is, when the discharge process is performed prior to the actual use as in the embodiment, the enclosed contact can be made into an enclosed contact whose opening / closing operation is stable.

The encapsulated contact of Example 202 was operated in the same manner as in the high load life test, and the resistance value between both ends at that time was measured. The relationship between the number of operations and the resistance value is shown in FIG. As is clear from FIG. 6, the enclosed contact of Example 202 has an operating life of up to 20 million times. As described above, the sealed contact to which the method of the present invention is applied has a stable resistance value between both electrodes of the sealed contact in both the life test under a low load and the life test under a high load.

In the above embodiments, the encapsulated contact after the electric discharge treatment has been described. However, even if the encapsulated contact is not subjected to the electric discharge treatment, if the electric discharge treatment is applied prior to its use, the above-mentioned embodiment is used. It goes without saying that the same effect as that described in the above item is realized. Further, even if the enclosed contact is once used, the same effect can be obtained by performing a discharge treatment during the use.

[0136]

As is clear from the above description, the encapsulated contact material of the present invention has a low contact resistance and a small variation, excellent contact operation life characteristics, and suppresses the use of expensive materials. Therefore, it can be manufactured at low cost. Further, according to the manufacturing method of the present invention, since the temperature of the contact base material is properly controlled, the composition, surface shape, and structure of the contact coating layer to be formed are stabilized, and variations in characteristics between manufacturing lots are suppressed. Get smaller.

Further, in all of the methods of manufacturing and using the encapsulated contact according to the present invention, since the encapsulated contact material that has been encapsulated is subjected to the discharge treatment, even if an oxide film is formed on the surface of the encapsulated contact material. The oxide film is removed by the discharge process, and the deterioration of the contact resistance of the sealed contact after the discharge process is suppressed.

[Brief description of drawings]

FIG. 1 is a sectional view showing a contact material A of the present invention.

FIG. 2 is a cross-sectional view showing a contact material B of the present invention.

FIG. 3 is a sectional view showing a contact material C of the present invention.

FIG. 4 is a graph showing the relationship between the number of opening / closing operations and the resistance value between both electrodes in a reed switch incorporating the contact materials of Example 2 and Comparative Example 1.

5 is a graph showing the relationship between the number of times of opening / closing operations and the resistance value between both electrodes in the reed switch of Example 202 and Comparative Example 61. FIG.

FIG. 6 is a graph showing the relationship between the number of operations and the resistance value between both electrodes when a life test is performed with a high load for the reed switch of Example 202.

[Explanation of symbols]

1 Contact base material 2A, 2B, 2C Contact coating layer 2C ₁ lower layer 2C ₂ upper layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Taiwa Ohashi 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd.

Claims (12)

[Claims] 1. The surface of the contact base material is Mo, Zr, Nb,
At least one selected from the group of Hf, Ta, W is used as a substantial matrix, and Zn, C is added to the matrix.
d, Hg, Al, Ga, In, Tl, Ge, Sn, P
b, As, Sb, at least one selected from the group consisting of Bi is composed of a material containing 0.5 to 50 atomic%, and
An encapsulated contact material characterized by being coated with at least one contact coating layer having a thickness of 0.1 μm or more. 2. The surface of the contact base material is Mo, Zr, Nb,
At least one selected from the group of Hf and W is used as a matrix, and Zn, Cd, Hg and A are added to the matrix.
1, Ga, In, Tl, Ge, Sn, Pb, As, S
At least one contact coating layer made of a material containing 0.1 to 50 mol% of an oxide of at least one element selected from the group consisting of b and Bi, and having a thickness of 0.1 μm or more. Encapsulated contact material characterized by being coated. 3. The surface of the contact base material is Mo, Zr, Nb,
At least one underlayer of at least one selected from the group of Hf, Ta, W, and Zn, Cd, Hg, Al,
Ga, In, Tl, Ge, Sn, Pb, As, Sb, B
at least one contact coating layer having a laminated structure having at least one upper layer of at least one selected from the group i, and the thickness of each of the lower layer and the upper layer is 0.1 μm or more. Encapsulated contact material characterized by being coated. 4. The contact coating layer comprises Zn, Cd, H
g, Al, Ga, In, Tl, Ge, Sn, Pb, A
The encapsulated contact material according to claim 1, wherein a concentration gradient is provided such that at least one selected from the group consisting of s, Sb, and Bi has a higher concentration on the surface side. 5. The encapsulated contact material according to claim 1, wherein the contact coating layer contains 1 to 40 atomic% of O. 6. The encapsulated contact material according to claim 1, wherein the surface of the contact coating layer is covered with an uppermost layer made of a metal or a metal oxide, and the thickness of the uppermost layer is 0.05 μm or more. 7. The contact coating layer according to claim 1 or 2 on the surface of the contact base material, and the temperature of the contact base material is 300 to 900 ° C.
A method for manufacturing an encapsulated contact material, characterized in that the film is controlled and formed. 8. The temperature of the contact base material is 300 to 600 ° C.
The method for manufacturing the encapsulated contact material according to claim 7, wherein 9. When forming the contact coating layer according to claim 3 on the surface of the contact base material, the temperature of the contact base material when forming the lower layer is controlled to 300 to 600 ° C. to form the upper layer. A method for producing an encapsulated contact material, characterized in that the temperature of the contact base material is controlled to 50 to 500 ° C. 10. The method for producing an encapsulated contact material according to claim 9, wherein the temperature of the contact base material when the lower layer is formed is controlled to 400 to 800 ° C. 11. A method of manufacturing an encapsulated contact, comprising encapsulating the encapsulated contact material together with an inert gas in a hermetically sealed container and then discharging the encapsulated contact material. 12. A method of using an encapsulated contact, wherein the encapsulated contact material is discharged prior to or during use of the encapsulated contact formed by encapsulating the encapsulated contact material in an airtight container together with an inert gas.