JP7306879B2 - Electrical contact material and its manufacturing method, connector terminal, connector and electronic component - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electrical contact material and its manufacturing method, a connector terminal, a connector and an electronic component.

Electronic parts for consumer and vehicle use, for example, connector terminals that constitute electrical contact parts of connectors, contain copper (Cu) as a main component, such as brass, phosphor bronze, and Corson alloy, on the surface of a conductive base material. Electrical contact materials are used which are plated with nickel (Ni) or Cu and further plated with tin (Sn) or Sn alloy.

In recent years, the electrification of vehicle drive systems has progressed in order to achieve fuel efficiency. For example, the connection parts between batteries, inverters, and motors are required to withstand high voltages and large currents. Examples of using silver (Ag) or Ag alloy plating in place of plating are increasing.

On the other hand, in such applications, for the purpose of improving the ease of assembly of vehicles, the conventional bolt-tightening connections are being replaced by mating-type connectors. Therefore, the plating formed on the surface of the connector, particularly the connector terminal, is required to have a low contact resistance value and a low insertion force when the connector is fitted (connected). However, Ag plating has good compatibility with metals and tends to cause agglomeration, which tends to increase the coefficient of dynamic friction and increase the insertion force.

For example, in Patent Document 1, a Ni layer (lower layer), an Ag layer (middle layer), an ε-AgSn layer (upper layer) and a Sn layer (outermost layer) are formed on a copper alloy substrate. A metallic material for electronic parts having adhesive abrasion resistance and high durability is disclosed.

JP 2014-29007 A

However, the metal material for electronic parts described in Patent Document 1 has an Sn layer as the outermost layer and has a higher contact resistance value than the Ag layer. is not applicable. Further, in the metal material for electronic parts described in Patent Document 1, a Ni layer is formed as a barrier layer (lower layer) between the copper alloy base material and the Ag layer (middle layer). Measures have been taken to prevent (Cu) from diffusing into the upper layer. Since it is not formed, there is a problem that the adhesion strength after heating in the heat treatment performed after lamination of each layer on the copper alloy base material is low.

The present invention has been made in view of the above circumstances. Even when a high voltage and large current is applied, it has a low contact resistance value with a sufficient level of resistance, a low dynamic friction coefficient, and a heat treatment applied after lamination of each layer on the copper alloy base material. An object of the present invention is to provide an electrical contact material which is also excellent in heat-resistant adhesiveness after heating in a heat exchanger, a method for producing the same, a connector terminal, a connector, and an electronic component.

In order to achieve the above-described object, the present inventors have made extensive studies and found that silver (Ag) and tin (Sn) are added to at least one side of a conductive substrate containing copper (Cu) as a main component. By forming a surface layer in which a large number of precipitates made of a specific intermetallic compound containing Sn are present in the mother phase containing as a main component, sufficient resistance even when a high voltage and large current is applied An electrical contact material that has a low contact resistance value with a high level, a low coefficient of dynamic friction, and excellent heat-resistant adhesion after heating in the heat treatment that is performed after lamination of each layer on a copper alloy substrate. Such an electrical contact material can be provided, for example, a layer containing Ag as a main component and a layer containing Sn as a main component on at least one side of a conductive substrate containing Cu as a main component. After laminating in random order and then performing a first heat treatment of heating at a heating temperature of 450 to 900 ° C., the surface layer is heated to a temperature lower than the heating temperature of the first heat treatment and at a temperature of 231 ° C. or higher. The inventors have found that it can be manufactured by applying the second heat treatment, and have completed the present invention.

That is, the gist and configuration of the present invention are as follows.
(1) At least one side of a conductive substrate containing copper (Cu) as a main component, a mother phase containing silver (Ag) and tin (Sn) as main components, a Sn content of 11.80 1. An electrical contact material characterized by having a surface layer formed with a large number of precipitates comprising an intermetallic compound of up to 22.85 at %.
(2) The electrical contact material according to (1) above, wherein the proportion of the metal compound present in the surface layer is 50% or more.
(3) An electrical contact according to (1) or (2) above, wherein a base layer containing nickel (Ni) as a main component is formed between the substrate and the surface layer. material.
(4) The electrical contact material according to (3) above, wherein an intermediate layer containing copper (Cu) as a main component is formed between the underlying layer and the surface layer.
(5) The electrical contact material according to any one of (1) to (4) above, wherein the surface layer has a thickness of 0.1 to 10.0 μm.
(6) A connector terminal using the electrical contact material according to any one of (1) to (5) above.
(7) A connector having the connector terminal according to (6) above.
(8) An electronic component having the connector according to (7) above.
(9) A method for producing an electrical contact material according to (1) or (2) above, wherein Ag is contained as a main component on at least one side of a conductive substrate containing Cu as a main component. A layer and a layer containing Sn as a main component are laminated in random order, then subjected to a first heat treatment of heating at a heating temperature of 450 to 900 ° C., and then at a temperature lower than the heating temperature of the first heat treatment and A method for producing an electrical contact material, characterized in that a second heat treatment is performed so that the surface layer is heated to 231° C. or higher.
(10) A method for producing an electrical contact material according to (3) above, wherein a base layer containing Ni as a main component is laminated on at least one side of a conductive substrate containing Cu as a main component. After that, a layer containing Ag as a main component and a layer containing Sn as a main component are laminated in random order on the underlayer, and then the first heat treatment is performed at a heating temperature of 450 to 900 ° C. and then performing a second heat treatment in which the surface layer is heated to 231° C. or higher at a temperature lower than the heating temperature of the first heat treatment.
(11) A method for producing an electrical contact material according to (4) above, wherein a base layer containing Ni as a main component and Cu are provided on at least one side of a conductive substrate containing Cu as a main component. A layer containing Ag as a main component and a layer containing Sn as a main component are laminated in random order on the intermediate layer, and then After performing a first heat treatment of heating at a heating temperature of 450 to 900 ° C., a second heat treatment is performed at a temperature lower than the heating temperature of the first heat treatment and so that the surface layer reaches 231 ° C. or higher. A method for producing an electrical contact material.

According to the present invention, even when a high voltage and large current is applied, it has a low contact resistance value with a sufficient resistance level, a low coefficient of dynamic friction, and furthermore, lamination of each layer on a copper alloy substrate It is possible to provide an electrical contact material, a method for producing the same, a connector terminal, a connector, and an electronic component that are also excellent in heat-resistant adhesion after heating in heat treatment that is performed after formation.

BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram of the material for electrical contacts of this invention. It is an example of a SEM photograph of the surface layer (the surface of) of the electrical contact material of the present invention.

Preferred embodiments of the present invention will be described in detail below, but the present invention is not limited to the following embodiments.

In the present invention, "containing M as a main component" (where M is one type of metal element) means that the content of the metal element M in the total metal elements contained in the substrate or each layer is 50 at% or more. It means that

1. Electrical contact material The electrical contact material of the present invention is a matrix containing silver (Ag) and tin (Sn) as main components on at least one side of a conductive substrate containing copper (Cu) as a main component. and a surface layer containing a large number of precipitates composed of an intermetallic compound having a Sn content of 11.80 to 22.85 at %.

FIG. 1 schematically shows a cross section of an electrical contact material of one embodiment according to the present invention. The electrical contact material 1 shown in FIG. Precipitation of an intermetallic compound having a Sn content of 11.80 to 22.85 at % in the intermediate layer 13 containing as main components and a mother phase containing silver (Ag) and tin (Sn) as main components It has a cross-sectional structure when a surface layer 14 in which a large number of substances are present is sequentially laminated.

Each part of the electrical contact material of the present invention will be described in detail below.

(Conductive substrate)
The conductive base material 11 contains copper as a main component.

Specifically, the conductive substrate 11 is made of a copper-based material such as (pure) copper or a copper alloy. The copper alloy is not particularly limited, but for example Cu--Zn system, Cu--Ni--Si system, Cu--Sn--Ni system, Cu--Cr--Mg system, Cu--Ni--Si--Zn--Sn--Mg system, etc. is mentioned.

The shape of the conductive base material 11 is not particularly limited, and may be appropriately selected according to the application.

The conductivity of the conductive base material 11 is not particularly limited, but is preferably 20%IACS or higher, more preferably 40%IACS or higher. As a result, the conductive material as a whole can have excellent conductivity. Here, the conductivity (IACS: International Annealed Copper Standard) can be obtained by measuring in a constant temperature bath controlled at 20° C. (±1° C.) using a four-probe method.

(Underlayer)
The underlying layer 12 contains nickel (Ni) as a main component, and is an optional component in the electrical contact material 1 . This base layer can prevent deterioration of conductivity of the electrical contact material 1 caused by diffusion of Cu in the conductive base material 11 to an intermediate layer 13 and a surface layer 14 to be described later.

Specifically, the underlying layer 12 is made of a nickel-based material such as metallic nickel or a nickel alloy. Examples of the nickel alloy include, but are not particularly limited to, Ni--P system, Ni--Fe system, and the like.

Although the thickness of the underlayer 12 is not particularly limited, it is preferably 0.1 to 3.0 μm, more preferably 0.3 to 2.0 μm. A method for calculating the thickness of the underlying layer will be described later.

It should be noted that even if a cobalt (Co)-containing layer or an iron (Fe)-containing layer is used for the underlying layer 12 instead of the Ni-containing layer made of a nickel-based material, the same effect as the Ni-containing layer can be obtained. .

(middle layer)
The intermediate layer 13 contains Cu as a main component and is an optional component in the electrical contact material 1 . The intermediate layer 13 further improves the adhesion between the underlying layer 12 and the surface layer 14 .

Specifically, the intermediate layer 13 is made of a copper-based material such as metallic copper or a copper alloy. The copper alloy is not particularly limited, but includes, for example, a Cu--Zn system.

Although the thickness of the intermediate layer 13 is not particularly limited, it is preferably 0.01 to 1.0 μm, more preferably 0.03 to 0.5 μm. A method for calculating the thickness of the intermediate layer 13 will be described later.

(surface)
The surface layer 14 is a mother phase containing silver (Ag) and tin (Sn) as main components, and a large number of precipitates of an intermetallic compound having a Sn content of 11.80 to 22.85 at%. is. Note that "containing silver (Ag) and tin (Sn) as main components" means that the content of silver is 40 at% or more and the content of tin is 10 at% of the total metal elements contained in the surface layer 14. It means that the total content of silver and tin is 50 at % or more. The content of the metal element measured by X-ray photoelectron spectroscopy is the ratio to the total elements detected by X-ray photoelectron spectroscopy.

In addition, "a large number of precipitates" gives an image as shown in FIG. 2, for example, when observed with a scanning electron microscope (SEM). FIG. 2 shows an example of a SEM photograph of the surface layer (surface) of the electrical contact material of the present invention.

An intermetallic compound having a Sn content of 11.80 to 22.85 at % means a phase mainly composed of Ag ₄ Sn (ζ-AgSn). Since ζ-AgSn has a high hardness, the dynamic friction coefficient can be reduced by forming a surface layer (especially the surface) in which many precipitates of an intermetallic compound containing ζ-AgSn as a main component exist. In addition, since ζ-AgSn has excellent conductivity, it can also reduce the contact resistance. Furthermore, even if ζ-AgSn is heated, the Cu present in the intermediate layer 13 and the conductive base material 11 is difficult to diffuse inside, so Cu diffuses to the surface of the surface layer 14 and is oxidized upon contact with the outside air. It is possible to suppress the decrease in conductivity caused by the above.

From such a point of view, the content of Ag in the precipitate of the intermetallic compound is not particularly limited, but is preferably 77.15 to 88.20 atomic %.

In addition, in the surface layer 14, it is preferable that the existence ratio of the above-described intermetallic compound having a Sn content of 11.80 to 22.85 at % is 50% or more. As described above, such an intermetallic compound lowers the coefficient of dynamic friction, lowers the contact resistance, and suppresses the decrease in electrical conductivity due to heating. These properties also tend to increase.

Precipitates existing on the surface of the surface layer 14 are preferably in the form of particles, and the average particle diameter thereof is preferably in the range of 0.01 to 10 μm. As a result, the electrical contact material 1 has a lower coefficient of dynamic friction and more excellent bending workability. Specifically, a rectangular visual field range is set so that 20 or more (400 or more in total) granular precipitates are included in each of the vertical and horizontal sides, and a diagonal line is drawn in this state. The average grain size of the granular precipitates is calculated by measuring the number of precipitates and dividing the diagonal length by the measured number of granular precipitates.

The thickness of the surface layer 14 is not particularly limited. is more preferred. When the surface layer 14 has such a thickness, the surface layer 14 has superior conductivity and excellent bending workability.

The electrical contact material 1 constructed as described above has a low contact resistance value with a sufficient resistance level even when a high voltage and large current is applied, and also has a low coefficient of dynamic friction. Such an electrical contact material can be used for connector terminals. Since such a connector terminal has a low coefficient of dynamic friction on the surface and a low insertion force, it can be used as a connector for improving assembly of vehicles and the like. Furthermore, such a connector can be used for various electronic components. In addition, in the present invention, each layer laminated on the conductive substrate may be formed on at least one side of the conductive substrate. For example, each layer laminated on a conductive base material may be formed in an electrical contact portion that is electrically connected by sliding contact with a terminal of a mating connector when the connector is connected (fitted). Often, it can be formed on one or both sides of the conductive substrate.

2. A method for producing an electrical contact material The method for producing an electrical contact material of the present invention is a method for producing the above-described electrical contact material, comprising: A layer containing Ag as a main component and a layer containing Sn as a main component are laminated in random order, and then subjected to a first heat treatment of heating at a heating temperature of 450 to 900 ° C., and then the heating of the first heat treatment. The second heat treatment is performed so that the surface layer is heated to 231° C. or higher at a temperature lower than the temperature.

The conductive substrate may be formed by laminating an underlayer containing Ni as a main component on at least one side thereof, and an underlayer containing Ni as a main component and an intermediate layer containing Cu as a main component may be used. A layer formed by stacking layers in this order may also be used. In each case, a layer containing Ag as a main component and a layer containing Sn as a main component may be laminated in any order on the underlayer or the intermediate layer.

More specifically, the method for producing the electrical contact material will be described. First, on at least one side of the conductive substrate, an underlayer containing Ni as a main component is optionally formed by plating, or an underlayer containing Ni as a main component and a base layer containing Cu as a main component are optionally formed by plating. The intermediate layers are laminated in this order. After that, a layer containing Ag as a main component and a layer containing Sn as a main component are formed by plating directly on the conductive substrate or indirectly via an underlying layer or an intermediate layer formed on the conductive substrate. Lamination is performed in random order (i.e., when a layer containing Ag as a main component is formed and then a layer containing Sn as a main component is formed, and after forming a layer containing Sn as a main component, Ag may be used in any case where a layer containing as a main component is formed by lamination). Next, after performing a first heat treatment that heats at a heating temperature of 450 to 900 ° C., the surface layer is heated to a temperature lower than the heating temperature of the first heat treatment and the surface layer is 231 ° C. (melting point of Sn) or higher. 2 Apply heat treatment. After that, it is cooled to obtain an electrical contact material. During the heat treatment, the Sn in the layer containing Sn as the main component and the Ag in the layer containing Ag as the main component, which are formed by plating, diffuse into the respective layers to form silver (Ag) and tin ( Sn) as a main component and a surface layer containing a large number of precipitates composed of an intermetallic compound with a Sn content of 11.80 to 22.85 at %.

The plating method for forming each layer is not particularly limited, but wet plating such as electrolytic plating and electroless plating, dry plating such as vapor deposition and sputtering, and the like can be used. Among these, wet plating is preferably used, and electrolytic plating is more preferably used. At this time, the plating conditions may be appropriately adjusted according to the plating method, the type and thickness of the plating layer, the temperature and holding time of the subsequent heat treatment, and the like.

The ratio of the thickness of the layer containing Ag as the main component to the thickness of the layer containing Sn as the main component (thickness ratio of Ag layer/Sn layer) is 2.1 to 7.0. is preferred, and 2.8 to 5.0 is more preferred. With such a ratio of 2.1 to 7.0, the mother phase containing silver (Ag) and tin (Sn) as main components has a Sn content of 11.80 to 22.85 at%. It becomes easy to obtain a surface layer containing a large number of precipitates of a certain intermetallic compound, and such an electrical contact material has excellent low contact resistance and dynamic friction coefficient.

In addition, a layer containing Ag as a main component and a layer containing Sn as a main component are not separately laminated in random order, but a layer containing Ag and Sn as main components (eg, Ag—Sn eutectoid layer). may be laminated, but in this case, the first heat treatment is not necessarily an essential component, and the second heat treatment may be started.

The first heat treatment may be performed at a heating temperature of 450 to 900.degree. C., preferably 470 to 700.degree. By performing the first heat treatment by heating at such a temperature, Sn in the layer containing Sn as a main component melts, and the melted Sn thermally diffuses in the layer containing Ag as a main component. An Ag—Sn alloy is produced, and as a result, an Ag—Sn alloy layer can be formed from a layer containing Sn as a main component and a layer containing Ag as a main component.

The heating time of the first heat treatment is preferably 5 seconds or more and 300 seconds or less, and particularly preferably 5 seconds or more and 200 seconds or less. By heating in such a short period of time, metals other than Sn and Ag can be prevented from diffusing into each other to form a component that lowers the electrical conductivity and the like.

As described above, the first heat treatment heats the entire laminated substrate obtained as described above at a high temperature for a short period of time. An induction heating device or the like can be used as a device for performing heating at a high temperature in a short period of time.

The first heat treatment is preferably performed under an inert gas atmosphere or a reducing gas atmosphere. Specifically, N ₂ , Ar, He, or the like can be used as the inert gas. Further, H ₂ , CO, CH ₄ , H ₂ +CO, or the like can be used as the reducing gas. By performing heat treatment in an inert gas atmosphere or a reducing gas atmosphere, oxidation of the metal in each layer can be prevented.

The second heat treatment is not particularly limited as long as the heating temperature is lower than the heating temperature of the first heat treatment described above and is 231 ° C. (the melting point of tin) or higher, but is, for example, 231 ° C. to 700 ° C. is preferred, and 250°C to 480°C is particularly preferred.

The second heat treatment preferably has a heating time of 5 seconds or more and 300 seconds or less, and particularly preferably 5 seconds or more and 200 seconds or less.

The second heat treatment is preferably performed under an inert gas atmosphere or a reducing gas atmosphere. Specifically, N ₂ , Ar, He, or the like can be used as the inert gas. Further, H ₂ , CO, CH ₄ , H ₂ +CO, or the like can be used as the reducing gas. By performing heat treatment in an inert gas atmosphere or a reducing gas atmosphere, oxidation of the metal in each layer can be prevented.

In the second heat treatment, the heating is performed as described above, so that a precipitate composed of an intermetallic compound having a Sn content of 11.80 to 22.85 at % is deposited on the surface layer. Therefore, the heating by the second heat treatment may heat at least the surface layer, and for example, the surface layer can be heated using a burner. By heating only the surface layer in this way, while promoting the precipitation of an intermetallic compound with a Sn content of 11.80 to 22.85 at% in the surface layer, the metals of each layer diffuse to each other, and the performance It is possible to further prevent the generation of components that lower the

When only the surface layer is heated, the reaching temperature of the surface (the surface of the surface layer) is preferably, for example, 231°C to 700°C, and particularly preferably 250°C to 480°C. When only the surface layer is heated, the difference between the temperature reached on the surface and the temperature reached on the back surface (conductive substrate) is preferably 50° C. or higher, more preferably 100° C. or higher.

EXAMPLES Next, examples and comparative examples will be described in order to further clarify the effects of the present invention, but the present invention is not limited to these examples.

Samples of Examples 1 to 24 were produced by one of the manufacturing methods A to C shown below. In addition, samples of Comparative Examples 1 to 6 were produced by any of the following manufacturing methods D to H. The structures and properties of the produced samples were evaluated, and the results are shown in Table 1 together with the production conditions.

(Measurement of thickness of Ag layer before heating, Sn layer before heating, underlayer and intermediate layer)
According to the fluorescent X-ray test method of JIS H8501:1999, the surface of each sample prepared was subjected to fluorescent X-ray analysis and measured. In addition, in order to confirm the thickness of each layer, the thickness of the cross section was also measured by an image analysis method. The image analysis method was performed according to the scanning electron microscope test method of JIS H8501:1999.

(X-ray photoelectron spectroscopy)
The X-ray photoelectron spectroscopic analysis was performed under the following conditions using an XPS measuring device 5600MC manufactured by Ulvac-Phi. The specified elements are silver, tin, copper, nickel, carbon, and oxygen, and the concentration of each element is measured with the total of the specified elements 5.2 seconds after the start of measurement (0.2 nm depth) as 100%. Concentration analysis of elements was performed. In addition, the existence ratio of the intermetallic compound whose Sn content in the surface layer is 11.80 to 22.85 at% is the average value of the Sn content when measuring arbitrary 19 points in a rectangle of 10 mm × 10 mm. The ratio of the measurement points with the Sn content of 11.80 to 22.85 atomic % to all the measurement points was defined as the existence ratio.
Vacuum attainment 1×10 ⁻¹⁰ Torr (1×10 ⁻⁸ Torr when Ar gas is introduced)
X-ray: monochromatic Al-Kα
Detection area: 50 μmφ
Output: 200W
Ion beam: ion species Ar + acceleration voltage 3 kV
Sample incident (angle between sample and detector): 45° each
Sputtering rate: 2.3 nm/min (in terms of _SiO2 )

(Measurement of contact resistance value)
The contact resistance between the conductive material (each sample) and the Ag surface-coated overhanging material (oxygen-free copper C1020 with a 3 μm-thick Ag layer on the surface, the radius of curvature of the overhanging part is 5 mm) was measured by the four-terminal method. It was obtained by measuring by A 6220 type DC current source manufactured by TFF Keithley Instruments Co., Ltd. was used as a DC current source, and a current measuring device (2182A nanovoltmeter manufactured by the same company) was used for measuring electrical resistance. The contact resistance values were measured at five arbitrary points, the average value (n=5) was calculated for each, and the values were evaluated according to the following criteria.
◎: Less than 10 mΩ ○: 10 mΩ or more and less than 20 mΩ ×: 20 mΩ or more

(Measurement of dynamic friction coefficient)
Using a surface property measuring machine (manufactured by Shinto Kagaku Co., Ltd., TYPE: 14), the surface on which the surface layer of each sample is formed is covered with an Ag surface-coated overhanging material (oxygen-free copper C1020 having an Ag layer with a thickness of 3 μm on the surface layer. , the curvature radius of the overhanging portion is 5 mm), the moving speed is 100 mm / min, the sliding distance is 5 mm, the contact load is 5 N, and the conductive material is slid back and forth 15 times. It was measured as a coefficient and evaluated according to the following criteria.
◎: less than 0.5 ○: 0.5 or more and less than 0.8 ×: 0.8 or more

(Heat resistance test)
Each sample was heated at 150° C. for 1000 hours in an air atmosphere. After heating, the contact resistance value after heating was obtained according to the method for measuring the contact resistance value described above. The evaluation criteria were also the same. The heat-resistant adhesiveness measured after heating was evaluated according to the following criteria by performing a tape test method according to JIS H 8504:1999.
◎: A tape peel test was performed on each sample after heating at 150 ° C for 1000 hours, and the plating on the surface layer, etc. did not peel off. ×: A tape peel test was performed on each sample after heating at 150 ° C for 1000 hours, and the surface layer When the plating peels off

[Examples 1 to 8: Production method A]
Oxygen-free copper C1020 was electrolytically degreased, silver-plated in an alkaline cyanide silver bath, and tin-plated in a tin sulfate bath in this order to give a predetermined thickness. Next, a first heat treatment was performed for 5 to 180 seconds in a heat treatment furnace set at a temperature of 450 to 700° C. in an inert gas or reducing gas atmosphere. After that, heat treatment is performed for 5 to 200 seconds in a heat treatment furnace at a set temperature of 250 to 480 ° C., a second heat treatment is performed, the silver plating and the tin plating are alloyed, and then cooled to form a surface layer of Ag. -Sn alloy layer was formed.

[Examples 9 to 16: Production method B]
After the oxygen-free copper C1020 was electrolytically degreased and washed with an acid, nickel plating was performed in a sulfamic acid bath, tin plating was performed in a tin sulfate bath, and silver plating was performed in an alkali cyanide silver bath in this order to a predetermined thickness. Then, it was heated for 5 to 180 seconds in a heat treatment furnace set at a temperature of 450 to 700° C. in an inert gas or reducing gas atmosphere. After that, heat treatment is performed for 5 to 200 seconds in a heat treatment furnace at a set temperature of 250 to 480 ° C., a second heat treatment is performed, the silver plating and the tin plating are alloyed, and then cooled to form a surface layer of Ag. -Sn alloy layer was formed.

[Examples 17 to 24: Production method C]
After electrolytically degreasing and acid-cleaning the oxygen-free copper C1020, it is plated with nickel in a sulfamic acid bath, copper is plated in a copper sulfate bath, silver is plated in an alkaline cyanide silver bath, and tin is plated in a tin sulfate bath in this order to a predetermined thickness. It was applied so that it would be smooth. Then, it was heated for 5 to 180 seconds in a heat treatment furnace set at a temperature of 300 to 700° C. in an inert gas or reducing gas atmosphere. After that, heat treatment is performed for 5 to 200 seconds in a heat treatment furnace at a set temperature of 250 to 480 ° C., a second heat treatment is performed, the silver plating and the tin plating are alloyed, and then cooled to form a surface layer of Ag. -Sn alloy layer was formed.

[Comparative Example 1: Manufacturing Method D]
After the oxygen-free copper C1020 was electrolytically degreased and washed with an acid, it was plated with silver in an alkaline cyanide silver bath and then plated with tin in a tin sulfate bath in this order to a predetermined thickness. Next, in a reducing gas atmosphere, in a heat treatment furnace set at a temperature of 700° C., it was heated for 5 seconds and then cooled. No second heat treatment was performed.

[Comparative Example 2: Production Method E]
After the oxygen-free copper C1020 was electrolytically degreased and washed with acid, it was plated with nickel in a sulfamic acid bath, silver plated in an alkaline cyanide silver bath, and tin plated in a tin sulfate bath in this order to a predetermined thickness. Then, in a reducing gas atmosphere, in a heat treatment furnace set at a temperature of 600° C., it was heated for 20 seconds and then cooled. No second heat treatment was performed.

[Comparative Example 3: Manufacturing Method F]
After the oxygen-free copper C1020 was electrolytically degreased and washed with acid, it was plated with nickel in a sulfamic acid bath and then tin-plated in a tin sulfate bath in this order to a predetermined thickness. After heating for 10 seconds in a heat treatment furnace at 100° C., no Ag plating was formed by cooling, and the second heat treatment was not performed.

[Comparative Example 4: Manufacturing Method G]
After the oxygen-free copper C1020 was electrolytically degreased and washed with acid, it was plated with nickel in a sulfamic acid bath, copper plated in a copper sulfate bath, and silver plated in an alkali cyanide silver bath in this order to a predetermined thickness. No Sn plating was formed, and neither the first heat treatment nor the second heat treatment were performed.

[Comparative Examples 5 and 6: Manufacturing Method H]
After electrolytically degreasing and acid-cleaning the oxygen-free copper C1020, it is plated with nickel in a sulfamic acid bath, copper is plated in a copper sulfate bath, silver is plated in an alkaline cyanide silver bath, and tin is plated in a tin sulfate bath in this order to a predetermined thickness. After applying it so that it becomes thin, it was heated in a heat treatment furnace set at a low temperature of 600° C. in an inert gas atmosphere for 20 seconds or 100 seconds, and then cooled.

As can be seen from Table 1 above, the samples of Examples 1 to 24 had low contact resistance values and dynamic friction coefficients, and were excellent in heat-resistant adhesion after heating in the heat treatment. In addition, the samples of Examples 1 to 24 had a low contact resistance after heating, which was the same as the contact resistance before heating.

On the other hand, the samples of Comparative Examples 1 and 2, which did not undergo the second heat treatment in the manufacturing process and had a Sn content in the precipitates present in the surface layer measured by X-ray photoelectron spectroscopy, were larger than the appropriate range. The post contact resistance was high and the heat resistant adhesion was poor.

The sample of Comparative Example 3, in which the second heat treatment was not performed in the manufacturing process, the Cu layer (intermediate layer) was not provided, and the surface layer was formed only with tin (Sn), the contact resistance was high both before and after the heat treatment, The heat-resistant adhesion was also inferior.

The sample of Comparative Example 4, in which the first heat treatment and the second heat treatment were not performed in the manufacturing process and the surface layer was formed only with silver (Ag), had a high coefficient of dynamic friction and poor heat-resistant adhesion.

The sample of Comparative Example 5, which was not subjected to the second heat treatment in the manufacturing process and had a Sn content in the precipitates present in the surface layer measured by X-ray photoelectron spectroscopy, was larger than the appropriate range. The resistance was high and the heat-resistant adhesion was poor.

The sample of Comparative Example 6, in which the second heat treatment was not performed in the manufacturing process and the Sn content of the precipitates present in the surface layer was measured by X-ray photoelectron spectroscopy, which was less than the appropriate range, had a high dynamic friction coefficient and heat-resistant adhesion. was also inferior.

1 Electrical contact material 11 Conductive base material 12 Base layer 13 Intermediate layer 14 Surface layer

Claims (10)

A conductive base material containing copper (Cu) as a main component, a mother phase containing silver (Ag) and tin (Sn) as main components on at least one side, a base phase containing silver (Ag) and tin (Sn) as main components, and a Sn content of 11.80-22. A surface layer in which a large number of precipitates made of an intermetallic compound of 85 at% are present is formed, and the existence ratio of the intermetallic compound in the surface layer is 52.63% or more and 89.47% or less. Contact materials (except when a treated layer is further formed on the surface of the electrical contact material). 2. The electrical contact material according to claim 1 , wherein an underlying layer containing nickel (Ni) as a main component is formed between said conductive substrate and said surface layer. 3. The electrical contact material according to claim 2 , wherein an intermediate layer containing copper (Cu) as a main component is formed between said base layer and said surface layer. The electrical contact material according to any one of claims 1 to 3 , wherein the surface layer has a thickness of 0.1 to 10.0 µm. A connector terminal using the electrical contact material according to any one of claims 1 to 4 . A connector having the connector terminal according to claim 5 . An electronic component comprising the connector according to claim 6 . A method for producing the electrical contact material according to claim 1 ,
A layer containing Ag as a main component and a layer containing Sn as a main component are laminated in random order on at least one side of a conductive base material containing Cu as a main component, and then heated under an inert gas atmosphere or by reduction. After performing a first heat treatment of heating at a heating temperature of 450 to 900 ° C. in a gas atmosphere , in an inert gas atmosphere or a reducing gas atmosphere, the temperature is lower than the heating temperature of the first heat treatment and the surface layer is A method for producing an electrical contact material, characterized in that a second heat treatment is performed to heat the material to 231° C. or higher. A method for producing the electrical contact material according to claim 2 ,
A base layer containing Ni as a main component is laminated on at least one side of a conductive substrate containing Cu as a main component, and then a layer containing Ag as a main component and Sn are formed on the base layer. Layers containing as the main component are laminated in random order, then subjected to a first heat treatment of heating at a heating temperature of 450 to 900 ° C. under an inert gas atmosphere or a reducing gas atmosphere , and then under an inert gas atmosphere. Alternatively, a method for producing an electrical contact material, wherein a second heat treatment is performed in a reducing gas atmosphere at a temperature lower than the heating temperature of the first heat treatment and the surface layer is heated to 231° C. or higher. A method for producing the electrical contact material according to claim 3 ,
A base layer containing Ni as a main component and an intermediate layer containing Cu as a main component are laminated in this order on at least one side of a conductive substrate containing Cu as a main component, and then formed on the intermediate layer. Then, a layer containing Ag as a main component and a layer containing Sn as a main component are laminated in random order, and then heated at a heating temperature of 450 to 900 ° C. in an inert gas atmosphere or a reducing gas atmosphere. After performing the first heat treatment, performing a second heat treatment in an inert gas atmosphere or a reducing gas atmosphere at a temperature lower than the heating temperature of the first heat treatment and heating the surface layer to 231 ° C. or higher. A method for producing an electrical contact material, characterized by:

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