JPH1021772A - Sealed contact material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealed contact material with stable contact switching operation for a long time and long life. SOLUTION: A material has at least one layer of a 0.1μm or more thick covering layer comprising 0.5-50at.% at least one element selected from the additive element group comprising Zn, Cd, In, Tl, Sn, Pb, As, Sb, Bi, 5-20at.% at least one element selected from the group comprising Cu, Ag, Au, and the balance at least one element selected from the base element group comprising Mo, Zr, Nb, Hf, Ta, W, or at least one element selected from the base element group comprising Mo, Zr, Nb, Hf, Ta, W, and O (oxygen) on a contact base material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed contact material suitable for an electrode of a lead switch or the like which opens and closes in a non-oxidizing atmosphere and has a low contact resistance and can perform an opening and closing operation stably for a long period of time.

[0002]

2. Description of the Related Art A sealed contact material is used as an electrode of a reed switch or the like which opens and closes in a non-oxidizing atmosphere. Conventionally, for the encapsulated contact material, Ni-Fe alloy contact base material
Plates coated with elements such as Ag, Au, and Cu and coated with a layer of Rh or Ru having high electrical conductivity, hardness, and melting point and excellent wear resistance have been frequently used. Where Ag, Au, Cu
The reason for plating such elements is to prevent Rh or Ru of the coating layer from diffusing into the contact base material due to Joule heat or the like during opening and closing operations of the contact, and to prevent the Rh or Ru coating layer and the contact base material from being diffused. This is for improving the adhesiveness of the film.

However, the conventional encapsulated contact material has a problem in that the cost is high because Rh or Ru is expensive.
Therefore, the present inventors first set the Mo, W, R
An encapsulated contact material in which a coating layer containing e, Nb, or Ta as a main component is formed, and a non-oxidizable conductive thin layer is formed thereon has been proposed (JP-A-5-217451). Mo, Zr, Nb, H
Li, K, Ce, Cs, Ba, a metal layer (base) containing at least one element selected from the group consisting of f, Ta and W
We have proposed an encapsulated contact material having a coating layer formed by adding at least one element selected from the group consisting of Sr, Ca, Na, Y, La, Sc, Th, and Rb, or an oxide thereof (Japanese Patent Application No. Hei 6-316). 39114
No.).

[0004] However, in these contact materials, although the occurrence of arc discharge is macroscopically uniform, microscopic irregularities are formed on the entire coating layer by arc discharge.
In some cases, the contact area of the contacts fluctuates, or the contacts mesh with each other, resulting in poor opening / closing, resulting in a shortened contact life. Therefore, the present inventors, Zn on the contact substrate,
A coating layer composed of at least one element selected from the group consisting of Cd, Hg, Al, Ga, In, Tl, Ge, Sn, Pb, As, Sb, and Bi;
We have proposed an encapsulated contact material coated with a coating layer made of at least one element selected from the group consisting of Mo, Zr, Nb, Hf, Ta, and W, or a coating layer to which these oxides have been added (Japanese Patent Application No. 7-107). twenty three
No. 167), this contact material successfully improved switching failure under high load conditions where arc discharge occurs.

[0005]

However, according to the subsequent research, the encapsulated contact material proposed in the above-mentioned Japanese Patent Application No. Hei 7-23167 shows that the carbon material can be rubbed by rubbing the contacts under low load conditions where no arc discharge occurs. Under high load conditions where contact resistance rises rapidly and becomes unstable due to the formation or agglomeration of insulative compounds containing at the contact points, and under high load conditions where arc discharge occurs, the surface area becomes rough due to arc discharge and the contact area changes However, there is a problem that the contact resistance fluctuates every time the contact is opened and closed.

In view of the above, the present inventors have conducted intensive research and have found that adding any of the elements of Cu, Ag, and Au to the encapsulated contact material proposed in Japanese Patent Application No. 7-23167, It has been found that the generation or aggregation of the insulating compound is suppressed under the low load conditions, and that the surface roughness due to arc discharge is reduced under the high load conditions, and further research has been completed to complete the present invention. An object of the present invention is to provide a long-life encapsulated contact material in which opening and closing operations of contacts are stably performed for a long period of time.

[0007]

According to the first aspect of the present invention,
On the contact substrate, at least one element selected from the group consisting of Zn, Cd, In, Tl, Sn, Pb, As, Sb, and Bi is added at 0.5 to 50 at.
%, At least one element selected from the element group of Cu, Ag, and Au is contained at 5 to 20 at%, and the balance is at least one element selected from the base element group of Mo, Zr, Nb, Hf, Ta, and W, or Mo, Z
At least one coating layer of at least one element selected from the base element group of r, Nb, Hf, Ta, and W and O (oxygen) having a thickness of 0.1 μm or more is formed. It is a contact material.

[0008] The invention according to claim 2 is a method according to claim 2, wherein Z
at least one element selected from the group consisting of n, Cd, In, Tl, Sn, Pb, As, Sb, and Bi in an amount of 0.5 to 50 at%, O (oxygen)
Contains element at 40at% or less (including 0at%), with the balance being Mo, Zr, N
At least one lower coating layer having a thickness of 0.1 μm or more and made of at least one element selected from the group consisting of base elements b, Hf, Ta, and W is formed, and Zn, Cd, In,
50 at% or less (including 0 at%) of at least one element selected from the additive element group of Tl, Sn, Pb, As, Sb, and Bi; O (oxygen)
Contains 40at% or less of elements (including 0at%), and the balance is Cu, Ag,
Thickness consisting of at least one element selected from Au element group
An encapsulated contact material comprising at least one upper coating layer having a thickness of 0.1 μm or more.

[0009]

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-Fe-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 alloy, Cu-Ti alloy, and the like.

In the first aspect of the present invention, the base metal group of Mo, Zr, Nb, Hf, Ta, and W constituting the coating layer is a group of elements serving as the base of the coating layer and has a high melting point and high hardness. Improve the wear resistance and poor opening and closing of the layer. The base element group can provide the same effect as a simple substance, but the same effect can be obtained with an alloy or a substance containing oxygen. The content of this base element group in the coating layer is 30a
t% or more is desirable. Among the base elements, Zr, Nb,
Hf, Ta, etc. are relatively inexpensive, but conventionally, elements that have not been used much industrially.By using these elements, expensive elements such as Rh and Ru have been made useless. In this respect, the present invention is also advantageous in cost.

According to the first aspect of the present invention, the additive element group of Zn, Cd, In, Tl, Sn, Pb, As, Sb, and Bi constituting the coating layer is mainly used under a high load condition where arc discharge occurs. Stabilizes contact resistance and further enhances abrasion resistance and oxidation resistance. The reason for limiting its content to 0.5-50at% is that 0.5at
If it is less than 50%, the effect cannot be sufficiently obtained. Even if the content exceeds 50 at%, the effect is saturated. In the invention according to claim 1, the element group of Cu, Ag, and Au reduces and stabilizes the contact resistance. The reason for limiting this to 5 to 20 at% is that if it is less than 5 at%, its effect cannot be obtained sufficiently,
This is because the effect is saturated even if the content exceeds t%.
An appropriate amount of O (oxygen) increases the melting point and hardness of the coating layer and improves wear resistance. However, if O exceeds 40 at%, the coating layer becomes brittle and the contact life is reduced. Therefore, O is desirably 40 at% or less. The reason why the thickness of the coating layer is limited to 0.1 μm or more is that if the thickness is less than 0.1 μm, the effect cannot be sufficiently obtained.

According to a second aspect of the present invention, the coating layer is divided into a lower portion and an upper portion, and the lower coating layer is formed of Zn, Cd, In, Tl, Sn, Pb, and A.
The s, Sb, Bi additive element group, Mo, Zr, Nb, Hf, Ta, W base element group and O (oxygen), and the upper coating layer has the additive element group, O (oxygen) and Cu , Ag, and Au, so that the effect of reducing the contact resistance of the elements can be more efficiently exhibited. That is, under a low load condition in which arc discharge does not occur, an increase in contact resistance is greatly suppressed, and the contact resistance can be further stabilized even under a high load in which arc discharge occurs. Also, the thickness of the upper coating layer and the lower coating layer
The reason for limiting the thickness to 0.1 μm or more is that the effect is not sufficiently obtained if the thickness is less than 0.1 μm.

[0013]

The present invention will be described below in detail with reference to examples. (Example 1) 52 at% Ni-Fe of 1 mm long and 1 mm wide was used for the contact base material.
A sealed contact material was produced using an alloy plate. First, the surface of the contact substrate is ultrasonically cleaned with acetone for 5 minutes,
Further, it was washed by electropolishing using phosphoric acid. Next, this contact substrate is set in a vacuum chamber, and the inside of the chamber is
After evacuating to 10 ^-4 Pa or less, set the vacuum pump valve to the half-open state and reduce the exhaust conductance.
The inside of the chamber was stabilized at 1 × 10 ⁻¹ Pa by introducing Ar gas. Next, a voltage of -400 V was applied to the contact base material, and a high-frequency antenna of 0.2 kW was generated from a high-frequency antenna in the chamber.
The surface of the contact substrate was cleaned by ion bombardment with ions. Next, 0.66 Pa of Ar or Ar + O ₂
In a gas atmosphere, 3
An encapsulating contact material was manufactured by forming a coating layer by a direct current magnetron sputtering method. The target is a base element,
The additive element and any one element of the element group of Cu, Ag, and Au were used. The deposition rate and the oxygen pressure of the atmosphere in the chamber were varied.

Using the thus-obtained sealed contact materials as electrodes, N ₂ gas-filled reed switches were manufactured, and the opening and closing operation life of these reed switches was examined at room temperature. The switching operation life is 40AT (Amper) by applying a low load (5V-100μA-100Hz) that does not generate arc discharge or a high load (100V-0.5A-10Hz) that generates arc discharge between the electrodes.
The open / close operation is repeated by the drive magnetic field of (e Turn), and the number of operations until the open / close failure occurs or the number of operations until the resistance value between both electrodes of the reed switch reaches 1Ω or more. The contact resistance was measured by a four-terminal method to evaluate the stability of the contact function. The contact resistance is 1,3,
Measurement was performed at each operation of 5,7 × 10 ³ to 10 ⁹ , and the minimum value and the maximum value were obtained. The results are shown in Tables 1 to 12. In Tables 1 to 12, the thickness of the coating layer is indicated as the film thickness.

[0015]

[Table 1]

[0016]

[Table 2]

[0017]

[Table 3]

[0018]

[Table 4]

[0019]

[Table 5]

[0020]

[Table 6]

[0021]

[Table 7]

[0022]

[Table 8]

[0023]

[Table 9]

[0024]

[Table 10]

[0025]

[Table 11]

[0026]

[Table 12]

As is clear from Tables 1 to 12, the products of the present invention
(Nos. 1 to 140) showed that the operating life was as long as 0.7 × 10 ⁸ times or more and the maximum value of the contact resistance could be suppressed to 70 mΩ or less under the low load condition where arc discharge did not occur. In addition, under high load conditions where arc discharge occurs, the operating life is as long as 1.4 × 10 ⁶ times or more, the contact resistance is low overall, and the difference between the maximum and minimum contact resistance is small and the contact function is stable. Was. In addition, since the No. 100 had a large amount of O (oxygen), the number of operations was slightly reduced and the contact resistance was slightly increased as compared with the others.
On the other hand, No. 1 of the comparative example product does not contain any of Cu, Ag, and Au, and the thickness of the coating layer is thin. .3,16,17,20 do not contain additional elements, No.4,9,10,12,13,18,19 do not contain any of Cu, Ag, Au .5 and 6 have much Cu, so N
o.7,8,11,14 have a lot of additive elements such as Zn, so under any low load condition and / or high load condition, whether the operating life is short, the contact resistance is high, The variation was great.

(Example 2) 52 wt% Ni-Fe of 1 mm long and 1 mm wide
The surface of the contact substrate of the alloy plate was cleaned in the same manner as in Example 1. Next, this contact base material is set in a chamber of 0.66 Pa Ar or Ar + O ₂ gas atmosphere, and is heated and maintained at 400 ° C., and the surface of the contact base material is base-mounted on the target by a binary DC magnetron sputtering method. A lower coating layer was formed using the element and the additional element. Next, once inside the chamber 2 ×
^{Evacuate to} 10 ^-4 Pa or less, and then Ar gas or Ar + O
After the introduction of the _two gases, the substrate temperature was returned to normal temperature. Next, an upper coating layer was formed on the lower coating layer by a binary direct current magnetron sputtering method using the additive element group and the Cu, Ag, and Au element groups as targets to produce an encapsulated contact material. In forming the lower and upper coating layers, the deposition rate and the oxygen pressure of the atmosphere in the chamber were variously changed. The operating life of each of the obtained contact materials was examined in the same manner as in Example 1, and the contact resistance was measured. Table 13-
See Figure 22. In Tables 13 to 22, the lower coating layer is indicated as a lower film and the upper coating layer is indicated as an upper film. Further, the thickness of the coating layer was indicated as a film thickness.

[0029]

[Table 13]

[0030]

[Table 14]

[0031]

[Table 15]

[0032]

[Table 16]

[0033]

[Table 17]

[0034]

[Table 18]

[0035]

[Table 19]

[0036]

[Table 20]

[0037]

[Table 21]

[0038]

[Table 22]

As is clear from Tables 13 to 22, examples of the present invention
(Nos. 141 to 260) showed a significant increase in operating life even at a low load at which arc discharge does not occur and at a high load at which arc discharge occurs. In addition, the contact resistance was stable at a low maximum value and a small difference between the maximum value and the minimum value regardless of the level of the load. In the case of No. 200, since the lower coating layer had a large amount of O (oxygen), the number of operations was slightly reduced and the contact resistance was slightly increased as compared with the others. On the other hand, No. 21 of the comparative example has a small thickness of the lower and upper coating layers and does not contain additional elements in the upper coating layer. No.23 because the additive element is not contained in the upper coating layer
No. 24 has a large amount of oxygen in the lower coating layer, and No. 26 has a large amount of oxygen in the upper coating layer. Nos. 27, 29, 37, and 38 have small thicknesses of the upper coating layer, and No. 28 has no additional element in the upper coating layer. No.31, 33, and 35 do not contain any additional elements in the upper coating layer because of the large amount of oxygen and the amount of oxygen. , The operating life was short, the contact resistance was high, or the contact resistance varied widely.

[0040]

As described above, the encapsulated contact material according to the present invention greatly extends the operating life even at a low load where arc discharge does not occur or at a high load where arc discharge occurs, and the contact resistance is reduced. Regardless of the level of the load, the maximum value is low, the variation is small, and the contact characteristics are excellent.
Further, conventionally, using relatively inexpensive elements such as Zr, Nb, Hf, Ta, etc., which were rarely used industrially, the cost was reduced by eliminating the use of expensive elements such as Rh and Ru. I have. Therefore, there is an industrially significant effect.

Claims (2)

[Claims] 1. The method according to claim 1, wherein Zn, Cd, In, Tl, Sn, P
at least one selected from the group consisting of b, As, Sb, and Bi
Contains 0.5 to 50 at% of elements, 5 to 20 at% of at least one element selected from the group consisting of Cu, Ag, and Au, with the balance being Mo, Zr, N
a thickness comprising at least one element selected from the group consisting of base elements b, Hf, Ta and W, or at least one element selected from the group consisting of base elements Mo, Zr, Nb, Hf, Ta and W and an O (oxygen) element; An encapsulated contact material comprising at least one coating layer having a thickness of 0.1 μm or more. 2. The method according to claim 1, wherein Zn, Cd, In, Tl, Sn, P
at least one selected from the group consisting of b, As, Sb, and Bi
Element 0.5 ~ 50at%, O (oxygen) element 40at% or less (0a
thickness including at least one element selected from the group consisting of Mo, Zr, Nb, Hf, Ta and W.
At least one lower coating layer of 0.1 μm or more is formed,
On the lower coating layer, Zn, Cd, In, Tl, Sn, Pb, As, S
b, at least one element selected from the additive element group of Bi is 50
at% or less (including 0 at%), containing O (oxygen) element at 40 at% or less (including 0 at%), and the balance consisting of at least one element selected from the group consisting of Cu, Ag, and Au. Characterized in that at least one upper cover layer is formed.