JPH10219479A - Sealed contact material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive sealed contact material having a long contact service life even under a highly loaded conditions. SOLUTION: This material is the one in which a coating layer having >=0.1μm thickness is formed on a contact base material, and this coating layer has a compsn. contg. at least one element among Zn, Cd, In, Tl, Sn, Pb, As, Sb and Bi by 0.5 to 50at%, contg. at least one element of C and Si by 5 to 50at%, contg. 0 to 40at% O (oxygen), and the balance >=30at% Cu or Ag. Since the material contains adhesion reducing elements such as Zn, Cd, In, Tl, Sn, Pb, As, Sb, Bi or the like and furthermore contains arc damage dispersing elements of C or Si, adhesion does not occur between contacts even under high loads in which arc discharge is generated, and a good contact service life can be obtd. Moreover, it is inexpensive since expensive Rh, Ru, etc., are not used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inexpensive encapsulation which is suitable for an electrode of an encapsulation type lead switch, relay, etc. which opens and closes in a non-oxidizing atmosphere, in which the opening and closing operation is performed stably for a long period of time. Regarding contact materials.

[0002]

2. Description of the Related Art A sealed contact is an electrode that opens and closes in a glass or plastic sealed container in a non-oxidizing atmosphere, and has conventionally been made of Ag, Au, C on a Ni-Fe alloy base material.
A material in which a plating layer of u or the like is formed and a layer of Rh or Ru having a high melting point and excellent in electrical conductivity, hardness, and wear resistance is coated thereon is often used. Ag, Au, Cu
The plating layers such as
It also serves to prevent Rh or Ru of the coating layer from diffusing into the base material and to improve the adhesion between the Rh or Ru coating layer and the contact base material.

[0003]

However, the above-mentioned encapsulated contact material has a problem that the cost is high because expensive Rh or Ru is used. Therefore, an encapsulated contact material in which a Cu-Ni diffusion layer is formed on a Ni-Fe alloy base material has been proposed. However, this material needs to be coated with Rh or Ru because high-load conditions such as arc discharge cause switching failure between contacts.

[0004] From the above, the present inventors have conducted intensive research on contact materials that can be applied even under high load conditions.
Zn, Cd, In, Tl, Sn, Pb, As, Sb, B
It has been found that the addition of a low-melting element such as i suppresses the adhesion between the contacts, and that the addition of elements such as C and Si disperses the damage caused by the arc. Reached. SUMMARY OF THE INVENTION An object of the present invention is to provide an inexpensive encapsulated contact material that can stably open and close contacts for a long period of time even under high load conditions.

[0005]

According to the first aspect of the present invention,
A coating layer having a thickness of 0.1 μm or more is formed on the contact substrate,
The coating layer contains at least one element of Cu or Ag in an amount of at least 30 at%, Zn, Cd, In, Tl, Sn, P
0.5 to 50 at% of at least one element of b, As, Sb or Bi, 0.5 to 50 at% of at least one element of C or Si, and 0 to 40 at% of O (oxygen)
An encapsulated contact material, characterized in that it includes an inevitable impurity and the remainder consists of unavoidable impurities.

According to a second aspect of the present invention, there is provided the encapsulated contact material according to the first aspect, wherein a concentration variation of each alloy element in a thickness direction of the coating layer is ± 5 at% or less.

A third aspect of the present invention is the encapsulated contact material according to any one of the first and second aspects, wherein two or more coating layers having different compositions are formed.

According to a fourth aspect of the present invention, the coating layer is formed in two layers, and one of the coating layers (i) contains at least one element of Cu or Ag in an amount of 30 at% or more, and contains Zn, Cd, and I.
0 to 50 at% of at least one element of n, Tl, Sn, Pb, As, Sb or Bi; 0 to 50 at% of at least one element of C or Si;
-40 at%, the remainder is made of unavoidable impurities, and the other layer (t) contains at least one element of Cu or Ag by 20%.
at% or more, Zn, Cd, In, Tl, Sn, Pb, A
at least one element of s, Sb, or Bi is 50
4. The encapsulated contact material according to claim 3, wherein the material contains 0 to 50 at% of at least one element of C or Si, 0 to 40 at% of O, and 0 to 40 at% of O, with the balance being unavoidable impurities.

According to a fifth aspect of the present invention, the coating layer includes Zn,
Cd, In, Tl, Sn, Pb, As, Sb, or B
2. The method according to claim 1, wherein at least one element of i is contained with a concentration gradient in a thickness direction of the coating layer.
2. The encapsulated contact material according to any one of 2, 3, and 4.

According to a sixth aspect of the present invention, the coating layer contains at least one element of C or Si with a concentration gradient in the thickness direction of the coating layer. 2. The encapsulated contact material according to any one of 2, 3, 4, and 5.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a contact base material includes:
Any metal material having strength and conductivity is used. For example, Fe, Ni, Co, Ni-Fe alloy, Co-F
e-Nb alloy, Co-Fe-V alloy, Fe-Ni
-Al-Ti alloy, Fe-Co-Ni alloy, carbon steel, phosphor bronze, nickel silver, brass, stainless steel, Cu-Ni
-Sn-based alloys, Cu-Ti-based alloys and the like are used. In the present invention, when a base layer such as Ni is provided on the contact base material,
Diffusion of the contact base material into the coating layer is suppressed, and good contact characteristics can be stably obtained for a longer period.

In the present invention, Cu or Ag forming the coating layer is a metal element serving as a base of the coating layer, and imparts conductivity to the coating layer. The reason why the content is specified to be 30 at% or more is that if it is less than 30 at%, sufficient conductivity cannot be obtained.

Zn, Cd, In, Tl, Sn, Pb, A
s, Sb, or Bi reduces stickiness between contacts under high load conditions where arcing occurs. It also increases wear resistance. The reason why the content is specified in the range of 0.5 to 50 at% is that if the content is less than 0.5 at%, the effect cannot be sufficiently obtained, and if it exceeds 50 at%, the melting point is lowered and the contact is greatly consumed. . Hereinafter, various elements such as Zn are referred to as tackiness reducing elements.

C or Si has the function of dispersing the arc discharge over the entire contact portion. 0.5 ~ 50at
The reason why the content is specified in% is that if the content is less than 0.5 at%, the effect cannot be sufficiently obtained, and if it exceeds 50 at%, the coating layer becomes brittle and the surface is easily peeled off in a film form. Hereinafter, C or Si is referred to as an arc damage dispersing element. An appropriate amount of O (oxygen) increases the melting point and hardness of the coating layer to improve wear resistance. The reason for defining the content to be 0 to 40 at% is as follows.
If the content exceeds 0 at%, the coating layer becomes porous, becomes brittle, and the contact life is shortened. In the present invention,
The reason why the thickness of the coating layer is specified to be 0.1 μm or more is as follows.
If the thickness is less than 1 μm, a sufficient contact life cannot be obtained.

According to a second aspect of the present invention, the variation in the concentration of each element in the coating layer in the thickness direction is suppressed to a low level, that is, the coating layer is homogenized to reduce the variation over time of the contact characteristics. . When the concentration variation is ± 5at% or less,
In particular, the effect is remarkable.

According to a third aspect of the present invention, there is provided an encapsulated contact material in which two or more coating layers having different compositions are formed on a base material. For example, the base material side of the coating layer has good adhesion to the base material. By using a composition with a large amount of metal and a composition with a large amount of an element for reducing adhesion on the surface side, a sealed contact material having a long life and excellent contact characteristics can be obtained.

According to a fourth aspect of the present invention, in the specific example of the third aspect, the i-layer in which the amount of the tackiness reducing element is specified as small as 0 to 50 at% is provided on the substrate side, and the amount of the tackiness reducing element is 50%. ~ 8
By forming a t-layer, which is specified as 0 at%, on the surface side, it is possible to obtain a material having excellent adhesion to the base material and hardly causing adhesion between the contacts. Further, when the t layer is formed on the substrate side and the i layer is formed on the surface side, the stickiness reducing element gradually diffuses to the surface during use, so that a long-term stable contact life can be obtained. Here, the concentration of the tackiness reducing element in the entire coating layer is 0.1.
Adjust so as to be 5 to 50 at%. The concentration of the arc damage dispersing element (such as C) is 0 to 5 for both the i-layer and the t-layer.
However, when the concentration of the i-layer is less than 0.5 at%, for example, when the concentration of the arc damage dispersing element in the entire coating layer is 0.5 at%, it is added to the t-layer in an amount exceeding 0.5 at%. Adjust so that it is above. In the case of base metal (such as Cu),
When the base metal of the i-layer is less than 30 at%, the amount of the base metal of the t-layer is increased so that the base metal concentration of the entire coating layer becomes 30 at% or more.

According to a fifth aspect of the present invention, there is provided a material wherein the tackiness reducing element has a concentration gradient in the thickness direction of the coating layer,
For example, in the case where the concentration of the tackiness reducing element is increased so as to be higher on the surface side, sticking between the contacts can be prevented with a small amount of the tackiness reducing element. In the case where the concentration of the tackiness reducing element is graded so as to become lower on the surface side, the tackiness reducing element gradually diffuses to the surface of the coating layer during use, and a required amount of the tackiness reducing element is applied to the coating layer. Long-lasting on the surface.

The invention according to claim 6 is a material in which the arc damage dispersing element has a concentration gradient in the thickness direction of the coating layer, for example, such that the concentration of the arc damage dispersing element increases on the surface side. The graded one can prevent arc damage between contacts with a small amount of arc damage dispersing element. In the case where the concentration of the arc damage dispersing element is reduced so that it is lower on the surface side, the arc damage dispersing element gradually diffuses to the surface of the coating layer during use, and a required amount of the arc damage dispersing element is removed from the coating layer. Long-lasting on the surface. In the present invention, a vapor phase growth method such as a sputtering method is convenient for forming the coating layer.

[0020]

The present invention will be described below in detail with reference to examples. (Example 1) Ni-48 at% Fe alloy plate (1 x 1 x 0.2 m
m) was used as a contact base material to produce a sealed contact. First, the surface of the contact substrate was ultrasonically cleaned with acetone for 5 minutes, and further cleaned by electrolytic polishing using phosphoric acid. Next, this contact base material is set in a vacuum chamber, and the inside of the chamber is 2 × 1
After evacuating to 0 ^-4 Pa or less, the vacuum pump valve was half-opened, and Ar gas was introduced while reducing the exhaust conductance to stabilize the inside of the chamber at 1 × 10 ^-1 Pa. Next, 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 of the contact base material. Next, the inside of the chamber was set to an Ar or Ar + O ₂ gas atmosphere of 0.66 Pa,
One coating layer was formed on the surface of the contact substrate maintained at 400 ° C. The coating layer was formed by a ternary DC magnetron sputtering method. As the target, at least one of each of a base metal element, an arc damage dispersing element, and an adhesion reducing element was used. The amount of O was controlled by changing the oxygen partial pressure in the atmosphere. The deposition rate was varied.

Using each of the sealed contacts thus obtained, N ₂ gas-filled reed switches were manufactured, and the switching contact life of these reed switches was tested at room temperature.
The life of switching contacts is limited by the high load at which arc discharge occurs between the electrodes.
The switching operation was repeated under a driving magnetic field of 40 Ampere Turn under (100 V-0.5 A-10 Hz), and the number of operations (contact life) until the opening / closing failure occurred was expressed. The number of test tubes was 10 (n = 10) each. The results are shown in Tables 1 and 2. Tables 1 and 2
In cases where sudden malfunctions occurred, the numerical values are underlined.

[0022]

[Table 1] (Note) # remainder. * Unit at%.

[0023]

[Table 2] (Note) # remainder. * Unit at%.

As is clear from Tables 1 and 2, the present invention example
(Nos. 1 to 15) had a long contact life and no sudden malfunction. On the other hand, Nos. 1 to 3 of the comparative examples do not contain the arc damage dispersing element, and Nos. 4 to 6 do not contain the tackiness reducing element. , No. 8 has many arc damage reduction elements,
No. 9 and No. 10 had a short contact life because of the thin coating layer. Some of them caused sudden malfunctions.

(Example 2) An encapsulated contact material was produced in the same manner as in Example 1 except that the coating layer was formed in two layers on the contact substrate, and the contact life was tested in the same manner as in Example 1. .
The results are shown in Tables 3 to 5.

[0026]

[Table 3] (Note) Table: Surface side, group: Base material side. # Rest. * Unit at%.

[0027]

[Table 4] (Note) Table: Surface side, group: Base material side. # Rest. * Unit at%.

[0028]

[Table 5] (Note) Table: Surface side, group: Base material side. # Rest. * Unit at%.

As is clear from Tables 3 to 5, the examples of the present invention (N
o.16 to 29) had a long contact life and no sudden malfunction. When the thickness of the coating layer is the same, the contact life is longer than in Example 1 in which the coating layer is formed as a single layer, and the effect of forming the coating layer in two layers is recognized. On the other hand, No.11.12 of the comparative example has a large oxygen content, No.13 has no added arc damage dispersing element and adhesion reducing element, and No.14,17 has a thin coating layer thickness. No. 15 had a large number of arc damage dispersing elements on the surface side, and No. 16 had no contact metal life because no base metal element was added at all. Some of them caused sudden malfunctions.

(Example 3) An encapsulated contact was manufactured in the same manner as in Example 1 except that a coating layer was formed on the contact base material by giving a concentration gradient to the alloy element. The contact life was tested in the same manner as in Example 1. Table 6 shows the results.

[0031]

[Table 6] (Note) ♭ table: front side, back side: back side. # Rest. * Unit at%.

As is clear from Table 6, No. 1
Nos. 30 to 36 had a long contact life and no sudden malfunction. When the thickness of the coating layer is the same, the contact life is longer than in Example 1 in which the coating layer is formed as a single layer, and the effect of imparting a concentration gradient to the adhesion reducing element and / or the arc damage dispersing element is obtained. Is recognized.

Although the case where the coating layer is formed on the substrate having the contact size has been described above, the present invention is also applicable to the case where the coating layer is formed on a large-sized substrate and sized to the contact size to obtain an encapsulated contact. Similar effects can be obtained. The encapsulated contact material of the present invention can be used in various fields such as an encapsulated relay and an encapsulated switch. In an environment where Cu or Ag of the base metal does not react with sulfide in the atmosphere to deteriorate the contact characteristics, the present invention can be applied to a normal reed switch used in the atmosphere.

[0034]

As described above, the encapsulated contact material of the present invention is made of Zn, Cd, In, Tl, Sn, Pb, and A.
Since it contains an adhesion-reducing element such as s, Sb, and Bi, and contains an arc damage dispersing element of C or Si, adhesion does not easily occur between contacts even under high load conditions in which arc discharge occurs, and a good contact life is obtained. Can be Also, since expensive Rh and Ru are not used, the cost is low. Therefore, there is an industrially significant effect.

Claims (6)

[Claims] 1. A coating layer having a thickness of 0.1 μm or more is formed on a contact base material, said coating layer containing at least one element of Cu or Ag in an amount of 30 at% or more, Zn, Cd, In,
0.5 to 50 at% of at least one element of Tl, Sn, Pb, As, Sb or Bi, 0.5 to 50 at% of at least one element of C or Si, O (oxygen)
, And the balance is composed of unavoidable impurities. 2. The encapsulated contact material according to claim 1, wherein a concentration variation of each alloy element in a thickness direction of the coating layer is ± 5 at% or less. 3. The encapsulated contact material according to claim 1, wherein two or more coating layers having different compositions are formed. 4. A coating layer is formed in two layers, and one of the coating layers (i) contains at least one element of Cu or Ag in an amount of 30 at% or more, and contains Zn, Cd, In, Tl, Sn, Pb,
At least one element of As, Sb, or Bi is set to 0
0 to 50 at%, 0 to 50 at% of at least one element of C or Si, 0 to 40 at% of O (oxygen), the remainder is made of unavoidable impurities, and the other layer (t) is made of at least Cu or Ag. 20 at% or more of one element, Zn, Cd,
50 to 80 at% of at least one element of In, Tl, Sn, Pb, As, Sb, or Bi, C or Si
0 to 50 at% of at least one element and 0 to 4 of O
4. The encapsulated contact material according to claim 3, comprising 0 at%, with the balance being unavoidable impurities. 5. The coating layer includes Zn, Cd, In, Tl, and S.
5. The method according to claim 1, wherein at least one of n, Pb, As, Sb, and Bi is contained with a concentration gradient in a thickness direction of the coating layer. An encapsulated contact material according to any one of the above. 6. The coating layer according to claim 1, wherein at least one element of C or Si is contained with a concentration gradient in a thickness direction of the coating layer. 5. The encapsulated contact material according to any one of the above items 5.