JPH04322016A - Sealed contact material - Google Patents

Abstract

PURPOSE:To offer a sealed contact material having slight dispersion of its initial contact resistance and a long working life. CONSTITUTION:A sealed contact material essentially consisting of a contact base material, a contact coating layer formed by coating the surface of aforesaid contact base material, mainly composed of at least one kind to be selected from a group of carbide, nitride, boride, silicide and aluminate belonging to the periodical table IVa, Va, VIa and having the thickness in a range from 0.03 to 100mum and a hardly-oxidized conductive thin layer to be formed by coating the surface of aforesaid contact coating layer while having the thickness not less than 0.01mum. Oxidation of a contact part can be prevented by the action of the hardly-oxidized conductive thin layer, and adhesiveness of the contact base material and the contact coating layer is improved by an intermediate layer while a drop in the contact resistance of the contact and enhancement in an action life can be achieved.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to encapsulated contact materials, and more specifically, the present invention relates to encapsulated contact materials, and more specifically, they have a stable initial contact resistance, have a long operating life, and have little deterioration in performance as a contact even when the number of opening/closing operations increases. The present invention relates to an encapsulated contact material that can be manufactured at low cost.

0002

[Prior Art] Conventionally, materials for sealed contacts include Rh,
Ru and the like are generally used. This is Rh, Ru
This is because these materials have excellent conductivity, high hardness, and high melting point. However, Rh, Ru, etc., Ag, P
There is a problem that the price is high compared to t. Also,
When manufacturing contacts, the surface of the contact base material is plated with Au, Ag, Cu, etc. to prevent diffusion into the contact base material made of FeNi alloy, etc., and to improve adhesion to the contact base material. A layer is formed, and the above Rh layer is further formed on the layer.
, Ru, etc. are used for plating. Therefore, the process for manufacturing the contacts becomes complicated, resulting in a significant increase in manufacturing costs.

[0003] For this reason, an inexpensive material such as Cu, Cu alloy, Fe alloy, or Ni alloy is used as the base material of the contact, and the surface of this base material is directly coated with a material that has excellent corrosion resistance, oxidation resistance, and conductivity. Contacts coated with compounds (ceramics) such as TiN and ZrN, which have properties of
(Refer to Publication No. 7, Japanese Patent Application Laid-open No. 159028/1983, etc.).

[0004] Furthermore, in International Publication No. WO 90/13685, the surface of the contact base material is coated with the periodic table IVa, Va, V.
A layer of carbide, nitride, boride, silicide, or aluminide of any element belonging to Group Ia formed by plasma CVD, sputtering, ion-assisted vapor deposition, ion plating, etc. is disclosed. has been done. The same publication further states that ceramics having a gradient composition by changing the composition in the layer thickness direction or an intermediate layer of soft metal are interposed between each of the ceramic layers and the contact base material. , a contact material with improved adhesion between a contact layer and a base material is disclosed.

[0005]

[Problems to be Solved by the Invention] However, in the case of the contact material having the ceramic coating layer described above, when it is sealed in a glass enclosure, the surface layer of the coating layer progresses to oxidation, resulting in , the initial contact resistance of the manufactured encapsulated contacts increases.

Furthermore, as the number of opening/closing operations increases, that is, the number of times the contact is used as a contact increases, the amount of heat generated in the contact increases, causing the contact to move, and the operating life of an enclosed contact becomes shorter. The problem is that it is short in scope. The present invention solves the above problems in the contact material disclosed in International Publication No. WO 90/13685, and prevents oxidation of the surface layer of the contact coating layer.
The purpose of the present invention is to provide an encapsulated contact material that has small variations in initial contact resistance and has a long operating life.

[0007]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention includes a contact base material, and a contact base material formed by coating the surface of the contact base material,
A contact coating layer with a thickness of 0.03 to 100 μm containing as a main component at least one member selected from the group of carbides, nitrides, borides, silicides, and aluminides of any element belonging to Group Ia, and the contact coating layer. There is provided an encapsulated contact material characterized in that it essentially comprises an oxidation-resistant conductive thin layer with a thickness of 0.01 μm or more formed by coating the surface of the contact base material and the contact coating layer. The composition changes continuously from the bonding interface with the contact base material to the bonding interface with the contact coating layer, and the following formula: XYz (in the formula,
X represents any element belonging to groups IVa, Va, or VIa of the periodic table, Y represents any element of C, N, B, Si, or Al, and z represents 1 when Y is C or N. ≦z≦1,
A layer of a compound represented by a number satisfying 90≦z≦2 when Y is B or Si, and 0≦z≦3 when Y is Al, which is bonded to the contact base material. At the interface, the composition is expressed by z=0, and at the bonding interface with the contact coating layer, the composition is expressed by z=1, 2, or 3 depending on the type of Y. There is provided an encapsulated contact material characterized in that an intermediate layer is interposed, and further a soft metal layer having a thickness of 0.01 μm or more is interposed between the contact base material and the contact coating layer. An encapsulated contact material is provided that is characterized by:

First, in the contact material of the present invention, a relatively inexpensive material such as Cu, Cu alloy, Fe alloy, or Ni alloy is used for the contact base material. In the first contact material, a contact coating layer is formed directly on the surface of this contact base material, and an oxidation-resistant conductive thin layer is further formed thereon. Here, the contact coating layer contains any element belonging to groups IVa, Va, or VIa of the periodic table and C.
, carbide, nitride with any of N, B, Si, Al,
It is composed mainly of ceramics such as boride, silicide, or aluminide. These materials are
Both are electrically conductive materials. The thickness is set to 0.03 to 100 μm.

If the thickness of the contact coating layer is less than 0.03 μm, the good conductivity required for a contact material cannot be obtained, leading to an increase in contact resistance, and at the same time, the wear resistance is insufficient. A satisfactory operating life as a contact cannot be obtained. On the other hand, if the thickness exceeds 100 μm, the crystals of the ceramic will become coarse during the formation of this layer, which will be described later, and the surface of the formed layer will become rough, leading to an increase in contact resistance. Temperature rise occurs during operation,
At the same time, stable thermal conductivity cannot be obtained.

[0010] This contact coating layer is formed as follows. That is, first, the surface of the contact base material is polished to a smooth surface, then precision polished by electrolytic polishing, etc., and then,
After cleaning the polished surface by using ion bombardment, electronic shower, etc., plasma C
The above ceramic layer having a desired composition and a desired thickness is formed by applying a commonly used film forming technique such as a VD method, a sputtering method, an ion-assisted vapor deposition method, or an ion plating method.

[0011] This contact coating layer has high hardness and melting point, little transfer wear, and excellent wear resistance, so it has the effect of increasing the operating life of the contact and increasing the reliability of the contact. In addition,
Only one contact coating layer may be formed on the surface of the contact base material, but if the same or different types of ceramics are laminated to form multiple layers, the number of pinholes in the layer that occurs during film formation can be reduced. It is also effective because each layer has complementary characteristics to each other in the entire coating layer.

Next, the surface of this contact coating layer is coated with an oxidation-resistant conductive thin layer to be described later. The provision of this oxidation-resistant conductive thin layer is the most important feature of the contact material of the present invention, and this oxidation-resistant conductive thin layer prevents the oxidation of the contact coating layer described above, thereby making it suitable for use as a contact. Reduce variation in initial contact resistance.

The oxidation-resistant conductive thin layer is made of a material that is resistant to oxidation in the atmosphere and has electrical conductivity. Specifically, Ru, Rh, Pd, Re, Os, Ir, P
t, one or more oxidizable metals of Au, SnO
2, In2O3, PbO, PbO2, CdO,
Cd2 SnO4 , In-Sn oxide (ITO), V
2 O3 , FeO, Fe3 O4 , RuO2 , R
h2O3, RhO2, ReO2, ReO3,
It is composed of one or more conductive oxides of IrO2, TiO, and Ti2O3. Of these,
Ru, Rh, Re, Os, and Ir are suitable because they prevent the generation of brown powder by oxidizing themselves during contact operation, and their oxides have good conductivity. It is the material. The thickness is set to 0.01 μm or more.

[0014] If this thickness is less than 0.01 μm, the contact resistance of this thin layer increases, and the effect of pinholes during film formation is exposed, causing the contact coating layer to lose its function as an oxidation-preventing film. . This oxidation-resistant conductive thin layer may be formed by a plasma CVD method, a sputtering method, an ion-assisted vapor deposition method, an ion plating method, etc., as in the case of the contact coating layer, and it must be electrically conductive. Therefore, it may be formed by electrolytic plating.

[0015] The second contact material of the present invention is the first contact material described above.
In this contact material, an intermediate layer having a composition gradient described below is interposed between the contact base material and the contact coating layer. This intermediate layer increases the adhesion between the contact base material and the contact coating layer, and also alleviates the stress generated due to the difference in thermal expansion between the two to prevent peeling between them. Works to prevent cracks from forming.

[0016] This intermediate layer has the following formula: , where z is an index). In this case, the composition of the intermediate layer is characterized in that it changes in the layer thickness direction from the bonding interface with the contact base material to the bonding interface with the contact coating layer. At the bonding interface with the contact base material,
A compound with a composition of z = 0, that is, the above-mentioned X (metal element) itself, but as the layer thickness increases, the compound constituting the layer part becomes more and more of the above composition indicated by the number of 0 < z. At the bonding interface with the contact coating layer, the compound is represented by the maximum value of z determined according to Y.

That is, when Y is C or N, 0≦z
Indicates an increasing number in the range of ≦1, and the middle layer is X→X
Its composition has changed to (C,N). Also, Y is B
, Si, z represents an increasing number in the range of 0≦z≦2, and the intermediate layer at that time is X→X(B,Si)
Its composition has changed to 2. Further, when Y is Al, it represents an increasing number in the range of 0≦z≦3, and the composition of the intermediate layer at this time changes from X→XAl3.

By configuring the intermediate layer as described above, since the bonding between the contact base material and the intermediate layer is a bond between metal elements, the adhesion between the two is improved, and the contact coating layer and the intermediate layer are bonded to each other. Since the bonding is between the compounds that make up the contact coating layer, the adhesion between the two is also improved, and since the composition of the intermediate layer is graded as described above, stress within the contact coating layer is reduced. The stress is relaxed, and the difference in thermal expansion between the contact base material and the contact coating layer is also reduced, reducing stress, thereby suppressing cracking and peeling of the contact coating layer from the contact base material.

Furthermore, the presence of this intermediate layer suppresses the occurrence of pinholes in the manufactured contact material. The material constituting this intermediate layer has good electrical conductivity and excellent heat resistance, just like the contact covering layer. and,
Since the constituent material of this intermediate layer is a soft material, it lowers the actual hardness of the contact material and also lowers the contact resistance, which alleviates the kinetic energy applied to the contact part when the circuit is closed and contributes to reducing chattering. . As the chattering decreases, the number of occurrences of chattering arcs also decreases, so the operating life of the contact portion becomes longer. Furthermore, the occurrence of closing errors is significantly reduced, contributing to improved reliability as a contact point.

[0020] Furthermore, by forming the intermediate layer, the contact coating layer formed on this surface becomes smooth, and furthermore, the oxidation-resistant conductive thin layer formed on this layer becomes even smoother. , the contact resistance of the obtained encapsulated contact is stabilized. This intermediate layer, as in the case of the contact coating layer,
The film is formed as follows by applying a film forming technique such as a VD method, a sputtering method, an ion-assisted vapor deposition method, or an ion plating method.

That is, first, z=0 on the surface of the contact base material.
The above XYz having a composition corresponding to that of To form a film. The desired intermediate layer is formed by sequentially stacking layers whose compositions are graded in the layer thickness direction toward the composition of the contact coating layer.

[0022] At this time, the total thickness of the intermediate layer is 0.1
It is set to µm or more. If this thickness is less than 0.1 μm, it becomes difficult to form a layer having the above-mentioned gradient composition, and the effect of the intermediate layer is diminished. Further, the upper limit of the thickness of the intermediate layer may be appropriately determined based on the manufacturing cost and the relationship between the intended size of the encapsulated contacts and the distance between the contacts.

In the third contact material of the present invention, the intermediate layer in the second contact material is not formed from the XYz compound described above, but from a soft metal described later. This soft metal layer also exhibits the same effect as the intermediate layer in the second contact material. This soft metal layer consists of Ag, A
l, Au, Co, Cu, Fe, Mg, Ni, Pd, Pt
, Sr, Cr, and one or more elements belonging to groups IVa and Va of the periodic table.

[0024] The thickness of this soft metal layer is set to 0.01 μm or more. This is because if the thickness is less than 0.01 μm, many pinholes will occur, corrosion from these pinholes will progress, and the contact resistance will increase. Further, the upper limit of the thickness of the intermediate layer may be appropriately determined based on the manufacturing cost and the relationship between the intended size of the encapsulated contacts and the distance between the contacts.

[0025] This soft metal layer may be formed by plasma CVD, sputtering, ion-assisted vapor deposition, ion plating, etc., as in the case of the oxidation-resistant conductive thin layer described above. It may be formed by a plating method. Note that it is effective to form this soft metal layer by the method described above and then perform a diffusion treatment between the soft metal layer and the contact base material by further heat treatment, as this further improves the adhesion with the contact base material. .

[0026]

【Example】

Example 1 Made of 52% Ni-Fe alloy, cleaned with organic detergent,
Further, the base material of the reed switch contact whose surface had been cleaned by electrolytic polishing was set in a vacuum chamber, the inside of the tank was evacuated, and then ion bombardment treatment was performed with Ar ions to clean the surface of the base material.

Next, the substrate temperature was raised and maintained at 720° C., a mixed gas of about 1/2 Ar/N2 was introduced into the tank to create a vacuum of 1×10 −4 Torr, and an electron beam evaporation source was used. Zr was evaporated from. At the same time, the surface of the substrate was irradiated with nitrogen ions from an ion source to form a ZrN layer with a thickness of 1.0 μm by ion-assisted vapor deposition at a deposition rate of about 50 Å/sec. After that, the substrate temperature was lowered to 300 degrees and maintained, and while Pb was evaporated from the electron beam evaporation source in this state,
At the same time, oxygen ions are irradiated from the ion source to achieve a deposition rate of 2
A 0.1 μm thick PbO layer was formed on the ZrN layer at 0 Å/sec.

Example 2 A two-layered contact material was produced in the same manner as in Example 1, except that the thickness of the ZrN layer was 10 μm. Example 3 A two-layered contact material was produced in the same manner as in Example 1, except that the thickness of the ZrN layer was 80 μm.

Comparative Example 1 A two-layered contact material was produced in the same manner as in Example 1, except that the thickness of the ZrN layer was 0.002 μm. Comparative Example 2 A two-layered contact material was produced in the same manner as in Example 1, except that the thickness of the ZrN layer was 130 μm.

Example 4 A two-layered contact material was produced in the same manner as in Example 1, except that the thickness of the PbO layer was 0.01 μm. Example 5 A two-layer coating contact material was produced in the same manner as in Example 1, except that the thickness of the PbO layer was 1.0 μm.

Comparative Example 3 A two-layered contact material was produced in the same manner as in Example 1, except that the thickness of the PbO layer was 0.005 μm. Example 6 A two-layer contact material was manufactured in the same manner as in Example 1, except that the ion bombardment treatment with Ar was not performed.

Example 7 After cleaning the surface of the substrate by Ar ion bombardment in the same manner as in Example 1, the substrate temperature was raised to 600° C., and the substrate was passed through Ar gas ionized by an ionization mechanism consisting of an induction coil. Using the ion plating method, which promotes ionization of evaporated elements during the process, a 2.0μ thick layer is applied to the surface of the base material.
A TiB2 layer of 0.1 μm thick was formed on the TiB2 layer, and an Au layer of 0.1 μm thick was further formed on this TiB2 layer by the same ion plating method.

Example 8 In the same manner as in Example 1, the surface of a 52% Ni-Fe alloy base material was cleaned by Ar ion bombardment treatment, and then 30 ml of hydrogen gas (carrier gas) was poured into the tank. Nitrogen gas and titanium tetrachloride gas were introduced at a flow rate of 1.5 ml/sec and 0.4 ml/sec, respectively, to maintain the pressure inside the tank at 0.4 Torr, and the temperature of the substrate was maintained at 0.4 Torr. The temperature was set to 600° C., plasma was generated by high frequency waves of 1.5 KW and 13.56 MHZ, and a TiN layer with a thickness of 3.0 μm was formed on the surface of the base material by plasma CVD.

[0034] Next, the atmosphere in the tank was changed to an oxygen partial pressure of 2.
The atmosphere was changed to a mixed gas atmosphere of Ar and oxygen at 5×1-4 Torr (total pressure: 30 mTorr), and a layer of 0.1 μm thick was deposited on the TiN layer by direct current magnetron sputtering at 0.5 KW using pure Re as a target. ReO2
A layer was deposited. Example 9 In the same manner as in Example 1, the base material was subjected to ion bombardment treatment with Ar to clean the surface, and then the Ar gas pressure in the tank was reduced to 10
The substrate temperature was raised to 750°C at mTorr, and Zr
A thickness of 5.0 mm was applied to the surface of the base material by direct current magnetron sputtering with an output of 0.5 KW targeting B2.
A μm ZrB2 layer was deposited.

Next, the substrate temperature was lowered and maintained at 700° C., and the atmosphere in the tank was changed to a mixed gas atmosphere of Ar and oxygen with an oxygen partial pressure of 9.0×1-4 Torr (total pressure: 50 mTorr).
), the ZrB2
A 0.1 μm thick V2O3 layer was deposited on top of the layer. Example 10 In the same manner as in Example 1, the substrate was subjected to ion bombardment treatment with Ar to clean the surface, and then the Ar gas pressure in the tank was reduced to 5 m.
Torr and raise the substrate temperature to 800℃, TaC
A thickness of 2.0 μm T is applied to the surface of the base material using a DC magnetron sputtering method with an output of 0.5 KW targeting
An aC layer was formed.

Next, the substrate temperature was lowered and maintained at 300° C., the atmosphere in the tank was changed to Ar atmosphere, and a 0.3 KW direct current magnetron sputtering method using pure Ru as a target was applied to the TaC layer to a thickness of 0. A Ru layer of .1 μm was deposited. Example 11 First, in the same manner as in Example 8, a TiN layer with a thickness of 0.5 μm was formed on the surface of the base material by the plasma CVD method, and then, in the same manner as in Example 8, a DC magnetron was applied on this TiN layer. ZrB2 with a thickness of 0.5 μm by sputtering method
A layer was deposited. Furthermore, the substrate temperature was lowered and maintained at 200°C, the Ar gas pressure in the bath was set to 5 mTorr, and a 0.2 KW DC magnetron sputtering method using pure Au as a target was used to deposit a 0.1-thick film on the ZrB2 layer.
A μm thick Au layer was formed.

Example 12 In the same manner as in Example 1, a ZrN layer with a thickness of 2.0 μm was formed on the surface of the base material by ion-assisted vapor deposition, and then,
By the plasma CVD method in Example 8, this Zr
A TiN layer with a thickness of 3.0 μm was formed on the N layer. Next, the substrate temperature was lowered and maintained at 300° C., the atmosphere in the tank was changed to an Ar atmosphere of 5 mTorr, and a 0.4 KW DC magnetron sputtering method using pure Rh as a target was applied to the TiN layer to a thickness of 0.5 mTorr. After forming a 1 μm Rh layer, the whole was heated at 450°C for 30 minutes in the atmosphere.
Heat treated for minutes.

Conventional Example 1 Only a ZrN layer with a thickness of 1.0 μm was formed on the surface of the substrate by ion-assisted vapor deposition under the same conditions as in Example 1 without forming a PbO layer. Conventional Example 2 Only a ZrB2 layer with a thickness of 2.0 μm was formed on the surface of the base material by direct current magnetron sputtering under the same conditions as in Example 9 without forming a V2O3 layer.

Conventional Example 3 Only a TaC layer with a thickness of 2.0 μm was formed on the surface of the substrate by direct current magnetron sputtering under the same conditions as in Example 10 without forming a Ru layer. Conventional Example 4 A 300 μm thick Ag-30% Pd alloy plating layer was formed by chemical plating on one side of a 52% Ni-Fe alloy substrate whose surface had been cleaned by sequential cleaning with an organic detergent and electrolytic polishing. .

Conventional Example 5 A 1.0 μm thick Au layer was formed on one side of the base material by chemical plating, and a 2.0 μm thick Rh layer was further formed thereon by the same chemical plating method. The above 20 types of contact materials are sealed in glass to make a reed switch S.
As shown in Figure 1, this reed switch S is connected to a power source E (
50V) to form a circuit, and connect this circuit with a 100m
A current was applied to open and close the switch, and the contact resistance and switch temperature rise during closing were measured. In addition, the number of operations at which the cumulative failure rate due to welding or adhesion of the contacts was 50% or more was investigated.

Further, a heat cycle test was conducted in which the contact material before glass encapsulation was subjected to a heat cycle of heating and cooling at room temperature ←→400° C. 100 times, and at that time, appearance cracks on the surface of the contact were observed. No change in appearance: ◎; Cracks occurred: ○; Some cracks occurred: △. Furthermore, each contact material before glass encapsulation was exposed to air at 450°C for 50 minutes.
After leaving it for a while, it was sealed in glass to make a contact, and the contact resistance of the contact under the above conditions was measured to examine the oxidation resistance.

In addition, each contact material before glass encapsulation was left in a desiccator filled with saturated benzene vapor for 24 hours, and then encapsulated in glass to form a contact, and the contact resistance of the contact under the above conditions was measured. The organic gas corrosion resistance was investigated. The above results are collectively shown in Table 1. For reference, the overall cost is also listed, taking into account the material cost, the time required for layer formation, and the cost required for processing.

[0043]

[Table 1]

Example 13 A reed switch contact base material made of 52% Ni-Fe alloy and whose surface was cleaned by washing with an organic detergent and electrolytic polishing was set in a vacuum chamber, and then the chamber was evacuated.
The surface of the base material was cleaned by ion bombardment with Ar. Next, the substrate temperature was raised to 720°C, and the inside of the tank was heated to 1×10
Zr was deposited on the substrate from an electron beam evaporation source at a deposition rate of 50 Å/sec in a vacuum atmosphere of -6 Torr. after that,
While continuing to evaporate Zr under the above conditions, the amount of nitrogen ion irradiation from the ion source was increased over time to convert Zr to Zr.
A 0.5 μm thick intermediate layer having a composition gradient up to rN was formed by ion-assisted vapor deposition. The top layer of this intermediate layer is ZrN.

[0045] Next, a layer with a thickness of 1.0 μm is formed on this intermediate layer.
After forming a ZrN layer by ion-assisted vapor deposition, the substrate temperature was lowered and maintained at 300°C, and oxygen ions were irradiated from an ion source while Pb was evaporated at a deposition rate of 20 Å/sec from an electron beam evaporation source. Then, on top of the ZrN layer, a thickness of 0 is applied.
．． A 1 μm thick PbO layer was deposited. Example 14 A contact material was produced in the same manner as in Example 13, except that the thickness of the intermediate layer was 5.0 μm.

Example 15 A contact material was produced in the same manner as in Example 13, except that the thickness of the intermediate layer was 50 μm. Example 16 Except that the thickness of the ZrN layer was 10.0 μm,
A contact material was produced in the same manner as in Example 14.

Example 17 A contact material was produced in the same manner as in Example 14, except that the thickness of the ZrN layer was 80 μm. Comparative Example 4 A contact material was produced in the same manner as in Example 13, except that the thickness of the intermediate layer was 0.05 μm.

Comparative Example 5 Except that the thickness of the ZrN layer was 0.02 μm,
A contact material was produced in the same manner as in Example 14. Comparative Example 6 A contact material was produced in the same manner as in Example 14, except that the thickness of the ZrN layer was 130 μm.

Example 18 After cleaning the surface of the base material by Ar ion bombardment in the same manner as in Example 13, the temperature of the base material was raised to 750°C, and A
Using the ion plating method in R gas, first the amount of B evaporated is brought to zero and only Zr is evaporated to deposit Zr on the surface of the substrate, and then the amount of B evaporated is increased over time to finally change the composition. From Zr to Z by binary evaporation to become ZrB2
A 1.0 μm thick intermediate layer having a composition gradient up to rB2 was deposited on the substrate surface.

[0050] Thereafter, a layer with a thickness of 3.0 μm was formed on this intermediate layer.
Then, while evaporating V, oxygen ions were irradiated from an ion source to form a V2 O3 layer with a thickness of 0.1 μm on the ZrB2 layer. Example 19 A 2.0 μm thick intermediate layer having a gradient composition from Ti to TiB2 and a 1.0 μm thick TiB2 layer were formed using the same film forming procedure as in Example 18 with the substrate temperature at 650°C.
A film of V2O3 with a thickness of 0.1 μm was sequentially formed.

Example 20 The surface of the substrate was cleaned in the same manner as in Example 18. A in the tank
First, Zr was deposited on the surface of the substrate using a direct current magnetron sputtering method using pure Zr as a target by increasing the substrate temperature to 750° C. with an r gas pressure of 5 mTorr.
Then, using a binary target of Zr and C,
Thickness 3.0 having a gradient composition such that the composition eventually becomes ZrC by increasing the amount of C sputtered over time
An intermediate layer having a thickness of μm was formed.

[0052] Thereafter, a layer with a thickness of 0.5 μm is formed on this intermediate layer.
After forming a ZrC layer, the temperature of the substrate was lowered and maintained at 200°C, and Pt was sputtered to a thickness of 0.25°C on the ZrC layer.
A 2 μm thick Pt layer was deposited. Example 21 The surface was cleaned in the same manner as in Example 13 at a temperature of 650°C.
A film with a thickness of 0 having a gradient composition from Ti to TiN was applied to the surface of the base material using the same ion plating method as in Example 13.
．． After forming a 5 μm intermediate layer, a 0.5 μm thick TiN layer was formed on this intermediate layer, and the substrate temperature was set at 700°C.
The temperature was raised to
An iB2 layer was deposited.

[0053] Thereafter, the substrate temperature was lowered and maintained at 600°C, and the atmosphere in the tank was adjusted to an oxygen partial pressure of 2.5 x 10-4 Torr.
mixed gas atmosphere of Ar and oxygen (total pressure 30 mTorr)
), the above TiB2
A 0.1 μm thick ReO2 layer was deposited on top of the layer. Example 22 By using the same ion-assisted vapor deposition method as in Example 13, a substrate with a thickness of 2.0 mm having a gradient composition from Zr to ZrN was formed on the surface of the base material.
A 0 μm intermediate layer is formed, and an additional 1.0 μm thick layer is formed on top of this.
A ZrN layer was formed.

Next, ZrB2 was deposited on this ZrN layer at an Ar gas pressure of 10 mTorr and a substrate temperature of 750°C.
After forming a ZrB2 layer with a thickness of 1.0 μm by direct current magnetron sputtering method using
An Au layer with a thickness of 0.1 μm was formed on the ZrB2 layer by a 0.2 KW direct current magnetron sputtering method using pure Au as a target.

Conventional Example 5 Without forming a PbO layer, only an intermediate layer with a thickness of 0.5 μm and a ZrN layer with a thickness of 1.0 μm were sequentially formed on the surface of the base material under the same conditions as in Example 13. Conventional Example 6 In Example 18, a contact material was produced in which no V2 O3 layer was formed.

[0056] Regarding the above 15 types of contact materials, Example 1
In the same manner as in cases 12 to 12, the characteristics of each contact point were investigated. The results are summarized in Table 2.

[0057]

[Table 2]

Example 23 A reed switch contact base material made of 52% Ni-Fe alloy and whose surface was cleaned by washing with an organic detergent and electrolytic polishing was set in a vacuum chamber, and then the chamber was evacuated.
The surface of the base material was cleaned by ion bombardment with Ar. The substrate temperature was set to 300°C, and while Ag was deposited on the substrate surface using the ion-assisted vapor deposition method, Ar ions were irradiated from the ion source to form an intermediate layer of Ag with a thickness of 1.0 μm, and then the substrate was deposited. The temperature was set at 720° C., and nitrogen ions were irradiated from an ion source while evaporating Zr to form a ZrN layer with a thickness of 1.0 μm on the intermediate layer. Next, the substrate temperature was lowered to 300° C., and while evaporating Pb, oxygen ions were irradiated from an ion source to form a PbO layer with a thickness of 0.1 μm on the ZrN layer.

Example 24 A contact material was produced in the same manner as in Example 23, except that the thickness of the Ag intermediate layer was 10 μm. Example 25 A contact material was produced in the same manner as in Example 23, except that the thickness of the Ag intermediate layer was 50 μm.

Example 26 A contact material was produced in the same manner as in Example 23, except that the thickness of the ZrN layer was 10 μm. Example 27 A contact material was produced in the same manner as in Example 23, except that the thickness of the ZrN layer was 80 μm.

Comparative Example 7 A contact material was produced in the same manner as in Example 23, except that the thickness of the Ag intermediate layer was 0.005 μm. Comparative Example 8 A contact material was produced in the same manner as in Example 23, except that the thickness of the ZrN layer was 130 μm.

Example 28 After cleaning the substrate surface with Ar ion bombardment in the same manner as in Example 23, a 1.0 μm thick intermediate layer made of Au was formed by vacuum evaporation at a substrate temperature of 200° C. did. Next, add 30% hydrogen gas (carrier gas) into the tank.
The pressure inside the tank was maintained at 0.4 Torr by introducing nitrogen gas and titanium tetrachloride gas at flow rates of 1.5 ml/sec and 0.4 ml/sec, respectively. The temperature was raised to 650℃, the output was 1.5KW, 13.
Plasma was generated by a high frequency of 56 MHZ, and a TiN layer with a thickness of 1.0 μm was formed on the Au intermediate layer by plasma CVD.

Next, the atmosphere in the tank was adjusted to an oxygen partial pressure of 9.
V2 with a thickness of 0.1 μm was deposited on the TiN layer by changing the atmosphere to a mixed gas atmosphere of Ar and oxygen at 0×1-4 Torr (total pressure: 50 mTorr) and using a 0.5 KW DC magnetron sputtering method using pure V as a target. O3
A layer was deposited. Example 29 The substrate surface was cleaned in the same manner as in Example 23, and the Ar in the tank was removed.
The gas pressure was set to 5 mTorr, the substrate temperature was raised to 300°C, and a thickness of 1.5 mm was applied to the substrate surface using a 0.3 KW DC magnetron sputtering method using pure Ag as a target.
A 0 μm thick Ag layer was formed, and a 1.0 μm thick Cu layer was laminated on top of the Ag layer using pure Cu as a target to form a 2.0 μm thick intermediate layer consisting of the Ag layer and the Cu layer. A film was formed.

Next, the substrate temperature was raised and maintained at 650° C., and a 1.0 μm thick TiB2 layer was formed by direct current magnetron sputtering at 0.5 KW using TiB2 as a target at an Ar gas pressure of 10 mTorr. , a mixed gas atmosphere of Ar and oxygen with a total pressure of 30 mTorr in the tank (oxygen partial pressure: 2.5 × 10-4 Torr)
) to a thickness of 0.1 μm using a 0.5 KW DC magnetron sputtering method using pure Re as a target.
A ReO2 layer was formed.

[0065] After that, the whole body was heated for 5 minutes in a nitrogen atmosphere.
Heat treatment was performed at 00°C for 1 hour. Example 30 The surface of the base material was cleaned in the same manner as in Example 23, and the Ar in the tank was removed.
The gas pressure was set to 5 mTorr, the substrate temperature was raised to 500°C, and an intermediate layer of Ni with a thickness of 1.0 μm was formed on the surface of the substrate using a 0.5 KW DC magnetron sputtering method using pure Ni as a target. did.

Next, a ZrB2 layer with a thickness of 1.0 μm was formed by a 0.5 KW DC magnetron sputtering method using ZrB2 as a target at an Ar gas pressure of 10 mTorr while raising and maintaining the substrate temperature at 750°C. , the base material temperature was lowered and maintained at 720°C, and a thickness of 1 mm was deposited on the ZrB2 layer by ion-assisted vapor deposition.
．． A ZrN layer of 0 μm was deposited.

[0067] Thereafter, the substrate temperature was lowered and maintained at 200°C, and an Au layer with a thickness of 0.1 μm was formed on the ZrN layer by direct current magnetron sputtering with an output of 0.3 KW using pure Au as a target. . Example 31 The surface of the substrate was cleaned in the same manner as in Example 23, the tank was evacuated, and the substrate temperature was raised and maintained at 600° C., and a thickness of 0.5 μm was deposited on the surface of the substrate by vacuum evaporation. A Cu layer of 1.0 μm thick is formed on the Cu layer.
The i-layer is laminated to form a layer with a thickness of 1.5 and consisting of a Cu layer and a Ni layer.
An intermediate layer having a thickness of μm was formed.

Next, the substrate temperature was raised and maintained at 650°C, a 1.0 μm thick TiB2 layer was formed by direct current magnetron sputtering using TiB2 as a target, and the substrate temperature was further raised and maintained at 750°C. ,TaC
A TaC layer with a thickness of 0.5 μm was formed on the TiB2 layer by direct current magnetron sputtering using as a target.

After that, the base material temperature was lowered and maintained at 300° C., Ar gas was introduced into the tank to make the Ar gas pressure 1 mTorr, and the above-mentioned TaC was A 0.1 μm thick Ru layer was deposited on top of the layer. Example 32 The surface of the substrate was cleaned in the same manner as in Example 23, the inside of the tank was evacuated, and the substrate temperature was raised and maintained at 650° C., and Ti was deposited on the surface of the substrate by vacuum evaporation method. Thickness 1.0
A 1.0 μm thick intermediate layer was formed, and then a 1.0 μm thick TiN layer was formed on the Ti intermediate layer by ion-assisted vapor deposition.

[0070] The substrate temperature was lowered and maintained at 300°C, and Pt with a thickness of 0.1 μm was deposited on the TiN layer by vacuum evaporation.
Au layers with a thickness of 0.1 μm were sequentially formed. Above 12
The contact characteristics of each type of contact material were investigated in the same manner as in Examples 1 to 12. The results are summarized in Table 3.

[0071]

[Table 3]

[0072]

Effects of the Invention As is clear from the above description, the contact material of the present invention prevents surface oxidation at the contact portion by the action of the oxidation-resistant conductive thin layer as the outermost layer formed on the contact coating layer. effectively prevented. Therefore, variations in contact resistance are reduced, temperature rise is low, and operating life is extremely long.

Furthermore, as is clear from the characteristic results of Examples 13 to 32, when an intermediate layer made of a compound having a gradient composition or a soft metal is interposed between the contact base material and the contact coating layer, the contact base material The adhesion between the material and the contact coating layer is improved, and the contact life is further extended.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a circuit used to measure contact resistance of a switch.

[Explanation of symbols]

S switch C Cable R resistance E Power supply A Ammeter

Claims (6)

[Claims] 1. A contact base material; a carbide, nitride, boride, or silicide of any element belonging to groups IVa, Va, or VIa of the periodic table, which is formed by coating the surface of the contact base material; a contact coating layer with a thickness of 0.03 to 100 μm containing at least one selected from the group of aluminides as a main component;
The thickness formed by covering the surface of the contact coating layer is 0.0
An encapsulated contact material characterized by essentially comprising an oxidation-resistant conductive thin layer of 1 μm or more. 2. The encapsulated contact material of claim 1, wherein said contact coating layer comprises multiple layers. 3. The oxidation-resistant conductive thin layer is made of Ru, Rh
, Pd, Re, Os, Ir, Pt, Au, SnO2,
In2O3, PbO, PbO2, CdO, Cd2
SnO4, In-Sn oxide, V2O3, Fe
O, Fe3 O4 , RuO2 , Rh2 O3 , R
hO2, ReO2, ReO3, IrO2, Ti
2. The encapsulated contact material according to claim 1, comprising as a main component at least one member selected from the group consisting of O, Ti2 O3. 4. The encapsulated contact material according to claim 1, wherein the composition is continuous between the contact base material and the contact coating layer from the bonding interface with the contact base material to the bonding interface with the contact coating layer. and the following formula: z is 0≦z≦1 when Y is C or N, 0≦z≦2 when Y is B or Si, and 0 when Y is Al.
z=0 at the bonding interface with the contact base material.
In addition, at the bonding interface with the contact coating layer, an intermediate layer having a thickness of 0.1 μm or more and having a composition of z = 1, 2, or 3 depending on the type of Y is interposed. An encapsulated contact material characterized by: 5. The encapsulated contact material according to claim 1, wherein a thickness of 0.01 μm is provided between the contact base material and the contact coating layer.
An encapsulated contact material characterized in that a soft metal layer of m or more is interposed. 6. The soft metal layer is made of Ag, Al, Au.
, Co, Cu, Fe, Mg, Ni, Pd, Pt, Sr,
6. The encapsulated contact material according to claim 5, comprising at least one element selected from the group of Cr and any of the elements belonging to groups IVa and Va of the periodic table.