JP2019099848A - Copper terminal material and production method of the same - Google Patents

Abstract

To provide a copper terminal material and a production method of the same which eliminates processing of drainage etc. in a terminal material composed of copper or copper alloy.SOLUTION: In the copper terminal material 1 of the invention, a burned layer 3 including at least one kind of gold and silver, and at least one kind of platinum and palladium in a part of a surface of a substrate 2 composed of copper or copper alloy, is formed. In the burned layer 3, a component ratio of at least one kind of gold and silver is 10 mass% or more and 70 mass% or less, a component ratio of at least one kind of platinum and palladium is 30 mass% or more and 90 mass% or less, and a sum of each component ratios is 95 mass% or more.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a copper terminal material provided with a coating containing a noble metal such as platinum or palladium, which is useful as a terminal for a connector used to connect an electrical wiring of an automobile or a consumer device, and a method of manufacturing the same.

DESCRIPTION OF RELATED ART Conventionally, the terminal for connectors used for the connection of electrical wiring, such as a motor vehicle and a household appliance, is known. As a terminal material used as such a connector terminal, a plating layer composed of a metal such as nickel or cobalt is formed on the surface of a copper or copper alloy substrate as a base layer, and tin or the like is formed on the upper surface of the base layer. The terminal material in which the metal plating layer was formed is disclosed (for example, refer to patent documents 1).
In the terminal material described in Patent Document 1, since the plating layer of nickel, cobalt or the like is formed on the surface of the copper or copper alloy substrate, the copper or copper alloy is formed on the metal plating layer of tin or the like located on the surface. Diffusion of the copper component of the base material is suppressed.

  Moreover, in order to improve the reliability of the contact point of the terminal material, a method of partially plating a noble metal such as gold or silver on the contact point has been proposed (see, for example, Patent Document 2).

JP-A-8-7960 JP, 2000-87289, A

  However, in the terminal material described in Patent Document 1, since the underlayer such as nickel or cobalt is formed, the process is complicated. Since this base layer is formed using a plating method, it is necessary to treat the plating waste solution and to take measures to reduce the environmental load. In addition, in the partial plating method described in Patent Document 2, when partially plating noble metals such as gold and silver on contact points, processes and apparatuses such as masking become complicated, and use of poisons such as cyanide and treatment of waste liquid Measures are needed to reduce environmental load.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a copper terminal material which does not require treatment with waste liquid or the like in forming a film of a terminal material made of copper or copper alloy. Do.

  In the copper terminal material of the present invention, a fired layer containing at least one of gold and silver and at least one of platinum and palladium is formed on part of the surface of a substrate made of copper or copper alloy.

  In the present invention, since the fired layer contains at least one of platinum and palladium, diffusion of the copper component of the substrate to the fired layer can be suppressed. Further, since the fired layer contains at least one of gold and silver, when the copper terminal material is used as a connector, the contact resistance at the contact portion can be reduced, and the contact reliability can be improved. Therefore, as compared with the conventional configuration in which two layers of the base layer and the noble metal layer are formed on the surface of the base material made of copper or copper alloy, it is simple to form one fired layer on a part of the surface of the base material. By the configuration, the diffusion of the copper component can be suppressed and the contact reliability can be enhanced. In addition, since the film can be formed without using the plating method, it is not necessary to treat the waste solution generated when forming the underlayer or the noble metal layer by using the plating method, so that the environmental load can be reduced.

  In a preferred embodiment of the copper terminal material according to the present invention, at least one component ratio of gold and silver in the fired layer is 10% by mass to 70% by mass, and at least one component ratio of platinum and palladium is 30% by mass It is good that it is 90 mass% or less, and the sum of each said component ratio is 95 mass% or more.

Here, when the component ratio of at least one of gold and silver in the fired layer is less than 10% by mass, the contact resistance may be increased, and the contact reliability may be lowered. On the other hand, when the component ratio of at least one of gold or silver exceeds 70% by mass, the component ratio of at least one of platinum and palladium is less than 30% by mass, so the diffusion preventing effect of the copper component of the substrate to the fired layer Is reduced. Moreover, when the component ratio of at least one of platinum and palladium exceeds 90% by mass, the porosity in the fired layer becomes high, and the strength of the fired layer decreases. Furthermore, if the sum of the component ratio of at least one of gold and silver and the component ratio of at least one of platinum and palladium is less than 95% by mass, components other than these increase, and the contact reliability decreases, and The effect of preventing the diffusion of the copper component of the base material to the fired layer is reduced.
On the other hand, in the above aspect, the component ratio of at least one of gold and silver in the fired layer is 10% by mass to 70% by mass, and the component ratio of at least one of platinum and palladium is 30% by mass to 90% by mass Since the sum of the component ratios is 95% by mass or more, the diffusion of the copper component to the fired layer can be reliably suppressed, and the contact reliability can be further enhanced.

As a preferable aspect of the copper terminal material of this invention, it is good for the porosity of the said baking layer to be 20% or less.
When the porosity of the fired layer exceeds 20%, the strength of the fired layer is reduced. On the other hand, in the above aspect, since the porosity of the fired layer is 20% or less, the strength of the fired layer can be increased.

As a preferable aspect of the copper terminal material of the present invention, the film thickness of the fired layer is preferably 0.3 μm or more and 3.0 μm or less.
When the film thickness of the fired layer is 0.3 μm or less, the effect of preventing the diffusion of the Cu component from the base material is poor, and the contact reliability is lowered. When the film thickness exceeds 3.0 μm, sintering occurs. The porosity decreases and the porosity of the fired layer increases.
On the other hand, in the above aspect, since the film thickness of the fired layer is 0.3 μm or more and 3.0 μm or less, the diffusion of the Cu component from the base material can be reliably suppressed and the increase in porosity can be suppressed. And the contact reliability of the fired layer can be enhanced.

The method for producing a copper terminal material according to the present invention is a coating material comprising a powder of at least one of gold and silver and at least one powder of platinum and palladium on a part of the surface of a substrate made of copper or copper alloy. Is applied, and then the applied material is fired to form a fired layer.
According to such a configuration, it is possible to provide a copper terminal material capable of suppressing the diffusion of the copper component and improving the contact reliability without using a plating method or the like.

  According to the present invention, in the copper terminal material, firing is carried out including at least one kind of gold and silver and at least one kind of platinum and palladium in a part of the surface of the base made of copper or copper alloy at contact points of the terminal material. By forming the layer, it is possible to improve the contact reliability and to suppress the diffusion of the copper component, and it is possible to make unnecessary the treatment of waste liquid etc. in the film formation of the copper terminal material.

It is a sectional view showing typically the copper terminal material concerning one embodiment of the present invention. It is a flowchart which shows the manufacturing method of the copper terminal material of the said embodiment. It is sectional drawing which shows typically the state which is irradiating a laser beam to paste in the middle of manufacture of the said copper terminal material.

Hereinafter, an embodiment of the present invention will be described.
<Composition of copper terminal material>
In the copper terminal material 1 of the embodiment, as the cross section is schematically shown in FIG. 1, the fired layer 3 is laminated on the base material 2 made of copper or copper alloy.
The composition of the substrate 2 is not particularly limited as long as the substrate 2 is made of copper or a copper alloy.

The fired layer 3 has a thickness of 0.3 μm to 3.0 μm, and is a noble metal layer including at least one of gold (Au) and silver (Ag), and at least one of platinum (Pt) and palladium (Pd). It is. Since the fired layer 3 is a metal layer containing at least one of gold and silver and at least one of platinum and palladium, the fired layer 3 made of gold and platinum, the fired layer 3 made of gold and palladium, silver and platinum In addition to the fired layer 3 or the fired layer 3 formed of silver and palladium, the fired layer 3 such as gold, silver and platinum, or the like may be used as the fired layer 3 including three or more of these.
In any case, the thickness of the entire baked layer 3 is 0.3 μm or more and 3.0 μm or less. The baked layer 3 has a function of preventing the diffusion of copper from the base material 2. If the thickness is less than 0.3 μm, the effect of preventing the diffusion of copper is scarce, and if the thickness exceeds 3.0 μm Cracking is likely to occur during press working. When the thickness of the sintered layer 3 exceeds 3.0 μm, the sinterability decreases and the porosity of the sintered layer 3 increases.

In the fired layer 3, the component ratio of at least one or more of gold and silver is 10% by mass to 70% by mass, and the component ratio of at least one or more of platinum and palladium is 30% by mass to 90% by mass And the sum of the ratio of each component is set to 95 mass% or more. Therefore, when the fired layer 3 contains gold and silver and platinum or palladium, the component ratio of the total of gold and silver is 10% by mass to 90% by mass, and the fired layer 3 is formed of gold or silver When platinum and palladium are contained, the component ratio of the total of platinum and palladium is 30% by mass or more and 90% by mass or less.
The baked layer 3 has the function of preventing the diffusion of copper and enhancing the contact reliability of the copper terminal material 1 used as a connector, and in the baked layer 3, the proportion of at least one of gold and silver is 10% by mass. When it is less than the above, the contact reliability is lowered, while when at least one component ratio of gold or silver exceeds 70% by mass, at least one component ratio of platinum and palladium becomes less than 30% by mass. This is because the diffusion of the copper component of the material 2 into the sintered layer 3 can not be suppressed. Furthermore, when the sum of the component ratio of at least one of gold and silver and the component ratio of at least one of platinum and palladium is less than 95% by mass, the contact reliability and the diffusion of the copper component of the base 2 into the fired layer 3 Can not be effectively suppressed. Therefore, the sintered layer 3 may contain at least one of ruthenium, osmium, rhodium and iridium in a range of less than 5% by mass.
Moreover, when the component ratio of at least one of platinum and palladium exceeds 90% by mass, the porosity in the fired layer 3 is increased, and the strength of the fired layer 3 is reduced. For this reason, the porosity in the sintered layer 3 is set to 20% or less.

  For example, when the fired layer 3 is made of a platinum alloy (Au-Pt alloy or Ag-Pt alloy), the composition thereof is Au- (30 mass% to 90 mass%) Pt, or Ag- (50 mass% to It is preferable that it is 90 mass%) Pt. Moreover, when the baked layer 3 consists of palladium alloys (Au-Pd alloy or Ag-Pd alloy), the composition is Au- (35 mass%-90 mass%) Pd, or Ag- (75 mass%- It is preferable that it is 90 mass%) Pt. By using these component ratios, the diffusion of copper from the base material 2 to the sintered layer 3 can be suppressed, and the contact reliability can be enhanced.

Next, the manufacturing method of this copper terminal material 1 is explained.
First, a plate material made of copper or a copper alloy is prepared as the base material 2, and the copper terminal material 1 is manufactured in the order of steps shown in FIG.
First, pretreatment is performed to clean the surface of the plate material by degreasing, pickling or the like (pretreatment step).
Next, as a coating material for the sintered layer 3, for example, a paste 3 'in which a binder or a rheology modifier is mixed with metal powder is applied (paste application step). The metal powder contained in this paste 3 'is, for example, a mixture of at least one powder of gold and silver and at least one powder of platinum and palladium, and the component ratio of this metal powder is gold and The component ratio of at least one silver is 10% by mass to 70% by mass, and the component ratio of at least one platinum and palladium is 30% by mass to 90% by mass. The binder is preferably a polymer material having good thermal decomposability at 400 ° C. or less, and, for example, acrylic resin, urethane resin, polyacrylic acid, polyvinyl pyrrolidone, polyethylene imine, etc. are preferably used. is there. The rheology modifier is preferably a material capable of self-association in a solvent and increasing the viscosity of the solvent by a small amount, for example, 12-hydroxystearic acid, hydrogenated castor oil, benzylidene sorbitol and derivatives thereof It is preferable to use lauroyl-L-glutamic acid-α, γ-dibutylamide and the like. The viscosity of the paste 3 'containing the metal powder of such a component ratio is 1 Pa · s or more and 100 Pa · s or less, and the application of the paste 3' is performed by, for example, a dispenser.
In the present embodiment, although the paste 3 'containing the metal powder is applied by a dispenser, for example, an ink jet printer including an ink having a viscosity of 1 mPa · s or more and less than 1000 mPa · s is included. May be applied. At this time, the ink may be a mixture of the above metal powder with an alcohol solvent such as water, ethanol or isopropyl alcohol, or a solvent such as a hydrocarbon solvent such as toluene, dodecane, n-decane, tetradecane or AF-solvent. Is used. The metal powder may be, for example, an alloy powder such as a platinum alloy or a palladium alloy, and the component ratio thereof may be in the above range.

Thus, after applying paste 3 'on the base material 2 and drying it, as shown in FIG. 3, the laser beam L is applied to the surface of the paste 3' for a predetermined time (for example, 0.01 to 1) Irradiate and heat the paste 3 '. The laser beam L is a laser beam which is uniform in the irradiation plane (in the surface of the paste 3 ′), and the focal size of the laser beam L is set to 0.5 to 5 mm square. When the size of the portion where the baked layer 3 is formed is smaller than the focal size of the laser beam L, the laser beam L is irradiated without being scanned. On the other hand, when the size of the portion where the fired layer 3 is formed is larger than the focal point size of the laser light L, a scanning mirror such as a galvano mirror is used, and the laser is used for the entire portion where the fired layer 3 is formed. The light L is scanned (scanned) and irradiated (laser light irradiation step).
As the laser beam, a solid laser, a fiber laser, a semiconductor laser (LD) or a gas laser can be used. The wavelength of the laser beam is in the range of 400 nm to 11 μm, and the irradiation energy per unit area on the surface of the paste 3 'is 1.0 × 10 ² J / cm ^{2 to} 1.0 × 10 ⁶ J / cm ^2. Irradiate to become

Since laser light has the feature of being able to locally collect light of high energy density with uniform wavelength, the use of laser light eliminates the need for complicated processes. The paste 3 ′ can be fired in a short time to form the fired layer 3.
Thus, by subjecting the paste 3 'to the laser beam irradiation step, the component ratio of at least one or more of gold and silver is 10% by mass to 70% by mass, and the component ratio of at least one or more of platinum and palladium Is 30% by mass or more and 90% by mass or less, and the fired layer 3 having a sum of component ratios of 95% by mass or more is formed.

Thus, the copper terminal material 1 in which the sintered layer 3 is formed on a part of the surface of the base material 2 is subjected to pressing or the like to form a terminal in which the sintered layer 3 is disposed in a portion used as a contact. .
Since the terminal includes at least one of platinum and palladium in the component ratio in the portion where the fired layer 3 is laminated, the diffusion of copper from the substrate 2 to the fired layer 3 is effectively prevented. Can maintain excellent heat resistance. For example, even if it expose | bleached to the temperature of 200 degreeC for a long time (1000 hours), it can suppress that the copper of the base material 2 spread | diffuses in the baked layer 3. As shown in FIG.
In addition, since the fired layer 3 contains at least one of gold and silver having the component ratio described above, the contact resistance at the contact point can be reduced, and the contact reliability can be enhanced. Therefore, compared to the conventional configuration in which two layers of the base layer and the noble metal layer are formed on the surface of base material 2 made of copper or copper alloy, only one layer of baked layer 3 is formed on part of the surface of base material 2 With this simple configuration, the diffusion of the copper component can be suppressed and the contact reliability can be enhanced. In addition, since a film containing a noble metal can be formed without using a plating method, it is not necessary to treat the waste liquid generated when forming an underlayer or a noble metal layer using a plating method, so that the environmental load can be reduced.

  In addition, the detailed configuration is not limited to the configuration of the embodiment, and various modifications can be made without departing from the scope of the present invention.

  As a substrate, a material with a thickness of 0.25 mm of a CDA (Copper Development Association) alloy number shown in Table 1 was used. As pretreatment, electrolytic degreasing (using NaOH aqueous solution 60 g / l, liquid temperature 60 ° C., current density 2.5 ASD (A / dm 2), degreasing time 60 seconds) and pickling (10% aqueous sulfuric acid solution, liquid temperature 25 ° C.) , Immersion time 30 seconds).

In addition, the fired layer was formed by applying a paste on a substrate and irradiating the paste with a laser beam. The component ratio and the film thickness of the noble metal contained in this paste are as shown in Table 1.
The irradiation of the laser light is such that the wavelength of the laser light is 1070 nm and the irradiation energy per unit area on the paste surface is 1.5 × 10 ³ J / cm ² with respect to the predetermined area where the sintered layer is formed. It irradiated so that it might become. When the area where the fired layer is formed is larger than the focal point size, the entire area is irradiated by scanning the laser beam.

(Porosity of sintered layer)
The porosity of the fired layer was obtained by observing a cross section of the terminal material on which the fired layer was formed by polishing the cross section by cross section polishing using an electron microscope (SEM) and observing at a magnification of 5000 From the image, the percentage of the value obtained by dividing the total area of the voids in the fired layer by the area of the fired layer including the void was defined as the porosity.

(Thickness and thickness variation)
The film thickness and thickness variation of the fired layer are obtained by observing a cross section of the terminal material on which the fired layer is formed by polishing the cross section by cross section polishing using an electron microscope (SEM) at a magnification of 500 times The film thickness of the fired layer was arbitrarily measured at five places from the image obtained by the above, the average value of the film thickness at five places was taken as the film thickness, and the value of the standard deviation was taken as the film thickness variation.

(Evaluation method of initial resistance and contact resistance change rate)
The contact resistance of the baked layer on the outermost surface conformed to JCBA-T323, and the contact resistance at a load of 0.98 N was measured by a sliding method (1 mm) using a four-terminal contact resistance tester. First, after measuring the initial contact resistance immediately after the formation of the fired layer, as a heat treatment, the contact resistance was measured again after holding for 1000 hours in an air atmosphere at 200 ° C. using a thermostatic chamber.
As for the initial resistance value, those with less than 5 mΩ are regarded as “〇”, those with 5 mΩ or more and 10 mΩ or less are regarded as “Δ”, and those with more than 10 mΩ are regarded as “x”.
With regard to the contact resistance change rate, the change rate of the measured value after holding at 200 ° C for 1000 hours from the initial measurement is “◎” if less than 10%, “10% or more and less than 20%” A sample with 20% or more and less than 25% was designated as “Δ”, and one with 25% or more was designated as “X”.
The results are shown in Table 1.

  As can be seen from the results in Table 1, the fired layer containing at least one of gold and silver and at least one of platinum and palladium on a part of the surface of the substrate made of copper or copper alloy has all the initial resistance values. It was found that the contact reliability at the initial resistance value was high. In particular, in the fired layer formed on the substrate, the component ratio of at least one of gold and silver is 10% by mass to 70% by mass, and the component ratio of at least one of platinum and palladium is 30% by mass to 90% by mass Or less, in which the void ratio is 20% or less and the thickness of the fired layer is 0.3 μm or more and 3.0 μm or less, both the initial resistance value and the contact resistance change rate are “〇” This is especially true, and the contact reliability was high.

1 Copper terminal material 2 Base material 3 Firing layer 3 'paste (coating material)
L laser light

Claims (5)

  What is claimed is: 1. A copper terminal material characterized in that a sintered layer containing at least one of gold and silver and at least one of platinum and palladium is formed on a part of the surface of a substrate made of copper or copper alloy.   In the fired layer, at least one component ratio of gold and silver is 10% by mass to 70% by mass, and at least one component ratio of platinum and palladium is 30% by mass to 90% by mass, and each of them The sum of a component ratio is 95 mass% or more, The copper terminal material of Claim 1 characterized by the above-mentioned.   The porosity of the said baking layer is 20% or less, The copper terminal material of Claim 1 or 2 characterized by the above-mentioned.   The film thickness of the said baking layer is 0.3 micrometer or more and 3.0 micrometers or less, The copper terminal material as described in any one of Claim 1 to 3 characterized by the above-mentioned.   After applying a coating material containing at least one powder of at least one of gold and silver and at least one powder of at least one of platinum and palladium on a part of the surface of a substrate made of copper or copper alloy, the coating material applied C. to form a fired layer, and a method of manufacturing a copper terminal material.

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