阅读说明：本技术 镀敷材料及其制造方法 (Plating material and method for producing same ) 是由 平井悠太郎 荒井健太郎 足达俊祐 于 2020-01-22 设计创作，主要内容包括：本发明提供价廉的镀敷材料及其制造方法,该镀敷材料的表面的一部分上形成银镀膜并且在其他一部分上形成有锡镀膜,能够防止在对镀敷材料进行回流处理后银镀膜的接触电阻升高及表面变色。通过在由铜或铜合金构成的基材(10)的表面上形成镍镀膜(12),在该镍镀膜(12)的表面的一部分上形成银镀膜(16)并且在镍镀膜(12)的表面的其他部分的一部分上形成锡镀膜(20),以制作在基材(10)上的镍镀膜(12)的表面上形成有银镀膜(16)和锡镀膜(20)的镀敷材料后,通过对该镀敷材料的表面照射红外线进行加热,以对锡镀膜(20)进行回流处理,将锡镀膜(20)制成回流锡镀层(22)。(The invention provides an inexpensive plating material and a method for producing the same, wherein a silver plating film is formed on a part of the surface of the plating material and a tin plating film is formed on the other part of the surface of the plating material, and the increase of contact resistance and surface discoloration of the silver plating film after the reflow treatment of the plating material can be prevented. A plating material having a silver plating film (16) and a tin plating film (20) formed on the surface of a nickel plating film (12) is produced by forming the nickel plating film (12) on the surface of a base material (10) made of copper or a copper alloy, forming the silver plating film (16) on a part of the surface of the nickel plating film (12), and forming the tin plating film (20) on a part of the other part of the surface of the nickel plating film (12), and then heating the surface of the plating material by irradiating infrared rays to perform a reflow process on the tin plating film (20), thereby forming the tin plating film (20) into a reflow tin plating layer (22).)

1. A method for producing a plating material, characterized in that a plating material having a silver plating film and a tin plating film formed on the surface of a nickel plating film on a substrate is produced by forming a nickel plating film on the surface of a substrate made of copper or a copper alloy, forming a silver plating film on a part of the surface of the nickel plating film, and forming a tin plating film on a part of the other part of the surface of the nickel plating film, and then the tin plating film is made into a reflowed tin plating layer by heating the surface of the plating material by irradiating infrared rays thereto to reflow the tin plating film.

2. The method for producing a plating material according to claim 1, wherein a plating material having a silver plating film and a tin plating film formed on a surface of the nickel plating film is preheated without melting the tin plating film before the irradiation with infrared rays.

3. The method for producing a plating material according to claim 1, wherein the irradiation with infrared light is performed by an infrared lamp.

4. The method for producing a plating material according to claim 1, wherein the tin plating film is formed after the silver plating film is formed.

5. The method for producing a plating material according to claim 4, wherein a portion other than a part of the surface of the nickel plating film is covered with a mask member after the nickel plating film is formed and before the silver plating film is formed.

6. The method for producing a plating material according to claim 4, wherein a portion other than a part of the other portion of the surface of the nickel plating film and the surface of the silver plating film are covered with a mask member after the formation of the silver plating film and before the formation of the tin plating film.

7. The method for producing a plating material according to claim 1, wherein a part of the surface of the nickel plating film and a part of the other part of the surface of the nickel plating film are spaced apart from each other.

8. A plating material characterized in that a nickel plating layer is formed on the surface of a base material made of copper or a copper alloy, a silver plating layer is formed on a part of the surface of the nickel plating layer, a reflow tin plating layer is formed on a part of the other part of the surface of the nickel plating layer, and the contact resistance of the surface of the silver plating layer is 1m omega or less.

9. The plating material according to claim 8, wherein the silver plating layer and the reflowed tin plating layer formed on the surface of the nickel plating layer are spaced apart from each other.

10. A contact or terminal member, characterized in that the plating material according to claim 8 is used as a material.

Technical Field

The present invention relates to a plating material and a method for producing the same, and more particularly to a plating material used as a material for a contact point or a terminal member such as a connector, a switch, or a relay used for wiring of a vehicle-mounted or consumer electrical appliance, and a method for producing the same.

Background

Conventionally, as a material for a contact point of a connector, a switch, or the like, a terminal member, or the like, a plating material obtained by plating a base material, such as copper, a copper alloy, or stainless steel, which is relatively inexpensive and has excellent corrosion resistance, mechanical properties, or the like, with tin, silver, gold, or the like, depending on desired properties, such as electrical properties, solderability, or the like, has been used. In order to improve the adhesion between these plating layers and the base material, a plating material in which a base layer made of nickel is formed between these plating layers and the base material is also used.

A tin-plated material obtained by plating a base material such as copper, a copper alloy, or stainless steel with tin is inexpensive, but has poor corrosion resistance in a high-temperature environment. Further, a gold-plated material obtained by plating these base materials with gold has excellent corrosion resistance and high reliability, but the cost thereof increases. On the other hand, silver-plated materials obtained by plating these substrates with silver are less expensive than gold-plated materials and have better corrosion resistance than tin-plated materials.

Therefore, as a material of a terminal member such as a connector, a portion (fitting portion) where a male terminal and a female terminal are fitted is plated with gold or silver, and a plating material which is inexpensive and easily deformable and is plated with glossy tin or matte tin may be used in a portion (clamping portion) where an electric wire or the like is clamped.

Further, tin plating is generally performed by electroplating, and in order to relax the internal stress of the tin plating film and suppress the generation of whiskers, reflow treatment (treatment of melting tin plating by heating and then solidifying) is performed after electroplating. If the reflow treatment is performed after the tin plating as such, a part of tin diffuses into the raw material or the base component to form a compound layer, and a tin or tin alloy layer is formed on the compound layer.

In particular, in a plating material in which a portion for sandwiching an electric wire or the like made of aluminum or an aluminum alloy is tin-plated, since the resistance value is increased, it is necessary to perform a reflow treatment after tin plating in order to suppress an increase in the resistance value.

As such a plating material, it is known that a base plating layer of nickel is formed on one surface of a plate-shaped metal member made of copper or a copper alloy by electroplating, a silver plating layer is formed on the base plating layer by electroplating, a tin plating layer is formed by direct electroplating using the other surface of the plate-shaped metal member as a base, and then a reflow treatment is performed in a low oxygen concentration atmosphere having an oxygen concentration of 200ppm or less to heat the tin plating layer to 400 to 800 ℃.

Further, it is known that a reflow tin plating layer is formed on at least a part of a metal substrate, a reaction layer is formed at an interface with the reflow tin plating layer, the reflow tin plating layer and at least a part of the reaction layer are completely peeled off from the metal substrate, nickel plating is performed on at least a part of a region where the reflow tin plating layer and the reaction layer are completely peeled off to form a nickel plating layer, and tin plating is performed on at least a part of the nickel plating layer (for example, see patent document 2).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2002-134361 (paragraph No. 0033)

Patent document 2: international publication WO2015/092979 (paragraph number 0011)

Disclosure of Invention

Technical problem to be solved by the invention

When the plating material used as a material for a terminal member such as a connector is a plating material obtained by performing gold plating (excellent in oxidation resistance) on the fitting portion, performing tin plating on the clamping portion, and then performing reflow treatment, the contact resistance hardly increases even after heating in the reflow treatment. However, when the plating material used as a material for a terminal member such as a connector is a plating material in which silver plating (which is less expensive than gold plating) is applied to the fitting portion and tin plating is applied to the clamping portion and then reflow treatment is performed, there is a problem that contact resistance of the silver plating film increases after heating of the reflow treatment or the surface of the silver plating film discolors.

The method of patent document 1 requires equipment for heating in a low oxygen concentration atmosphere, and is expensive to manufacture. Further, even if the reflow treatment is performed in a low oxygen concentration atmosphere, the silver plating layer and the tin plating layer are heated at a high temperature in a coexistent state, and therefore, there is a possibility that the contact resistance of the silver plating layer increases or the surface of the silver plating layer discolors.

The method of patent document 2 requires a step of completely peeling at least a part of the reflow tin plating layer and the reaction layer, and thus the manufacturing cost is high. Further, when the reflow tin plating layer or the reaction layer is melted with a chemical agent and peeled off, there is a possibility that the reflow tin plating layer or the reaction layer is excessively peeled off.

In view of the above-described conventional problems, an object of the present invention is to provide an inexpensive plating material in which a silver plating film is formed on one part of the surface and a tin plating film is formed on the other part of the surface, and which can prevent an increase in contact resistance and surface discoloration of the silver plating film after a reflow process of the plating material, and a method for producing the same.

Technical scheme for solving technical problem

The present inventors have conducted extensive studies to solve the above-mentioned problems, and as a result, they have found that if a plating material having a silver plating film and a tin plating film formed on the surface of a nickel plating film on a substrate is produced by forming a nickel plating film on the surface of a substrate made of copper or a copper alloy, forming a silver plating film on a part of the surface of the nickel plating film, and forming a tin plating film on a part of the other part of the surface of the nickel plating film, and then heating the surface of the plating material by irradiating infrared rays thereto to reflow the tin plating film, thereby forming the tin plating film into a reflowed tin plating film, a plating material capable of preventing an increase in contact resistance and surface discoloration of the silver plating film after the reflowing of the tin plating film can be produced at low cost, and have completed the present invention.

That is, the method for producing a plating material according to the present invention is characterized by forming a nickel plating film on a surface of a base material made of copper or a copper alloy, forming a silver plating film on a part of the surface of the nickel plating film, and forming a tin plating film on a part of the other part of the surface of the nickel plating film to produce a plating material having a silver plating film and a tin plating film formed on the surface of the nickel plating film on the base material, and then irradiating infrared rays on the surface of the plating material to heat the plating material to reflow the tin plating film, thereby forming the tin plating film into a reflowed tin plating layer.

In the method for producing a plating material, it is preferable that the plating material having the silver plating film and the tin plating film formed on the surface of the nickel plating film is preheated in such a manner that the tin plating film is not melted before the irradiation with the infrared ray. Further, it is preferable that the infrared ray is irradiated by an infrared lamp. Further, it is preferable that a part of the surface of the nickel plating film and a part of the other part of the surface of the nickel plating film are spaced apart from each other.

In the above method for producing a plating material, it is preferable that the tin plating film is formed after the silver plating film is formed. In this case, it is preferable that a part other than a part of the surface of the nickel plating film is covered with a mask member after the nickel plating film is formed and before the silver plating film is formed. After the formation of the silver plating film and before the formation of the tin plating film, a part of the nickel plating film other than the part of the other surface and the surface of the silver plating film are preferably covered with a mask member.

The plating material of the present invention is characterized in that a nickel plating layer is formed on a surface of a base material made of copper or a copper alloy, a silver plating layer is formed on a part of a surface of the nickel plating layer, a reflow tin plating layer is formed on a part of the other part of the surface of the nickel plating film, and a contact resistance of the surface of the silver plating layer is 1m Ω or less.

In the plating material, it is preferable that the silver plating layer and the reflowed tin plating layer formed on the surface of the nickel plating layer are spaced from each other.

Effects of the invention

According to the present invention, an inexpensive plating material having a silver plating film formed on a part of the surface thereof and a tin plating film formed on the other part thereof can be produced, and the increase in contact resistance and the surface discoloration of the silver plating film after the reflow treatment of the plating material can be prevented at low cost.

Brief description of the drawings

Fig. 1A is a plan view illustrating a step of preparing a base material in the embodiment of the method for producing a plating material of the present invention.

Fig. 1B is a plan view illustrating a step of forming a nickel plating film in the embodiment of the method for producing a plating material of the present invention.

Fig. 1C is a plan view illustrating a process of attaching a masking tape to a part of the nickel plating film in the embodiment of the method for producing a plating material of the present invention.

Fig. 1D is a plan view illustrating a step of forming a silver plating film on a portion of the nickel plating film to which no masking tape is attached in the embodiment of the method for producing a plating material of the present invention.

Fig. 1E is a plan view illustrating a step of peeling off the masking tape after forming the silver plating film in the embodiment of the method for producing a plating material of the present invention.

Fig. 1F is a plan view illustrating a process of attaching a masking tape to the entire surface of the silver plating film and a part of the nickel plating film after peeling the masking tape in the embodiment of the method for producing a plating material of the present invention.

Fig. 1G is a plan view illustrating a step of forming a tin plating film on a portion of the nickel plating film to which no masking tape is attached in the embodiment of the method for producing a plating material of the present invention.

Fig. 1H is a plan view illustrating a step of peeling off the masking tape after forming the tin plating film in the embodiment of the method for producing a plating material of the present invention.

Fig. 1J is a plan view illustrating a step of performing reflow treatment of the tin plating film after peeling off the masking tape in the embodiment of the method for producing a plating material of the present invention.

Fig. 2A is a sectional view taken along line IIA-IIA of fig. 1A.

FIG. 2B is a sectional view taken along line IIB-IIB of FIG. 1B.

FIG. 2C is a cross-sectional view taken along line IIC-IIC of FIG. 1C.

FIG. 2D is a cross-sectional view taken along line IID-IID of FIG. 1D.

FIG. 2E is a cross-sectional view taken along line IIE-IIE of FIG. 1E.

FIG. 2F is a cross-sectional view taken along line IIF-IIF of FIG. 1F.

FIG. 2G is a cross-sectional view taken along line IIG-IIG of FIG. 1G.

FIG. 2H is a cross-sectional view taken along line IIH-IIG of FIG. 1H.

FIG. 2J is a sectional view taken along line IIJ-IIJ of FIG. 1J.

Detailed Description

Next, an embodiment of the method for producing a plating material according to the present invention will be described in detail with reference to the drawings.

In the embodiment of the method for producing a plating material according to the present invention, as shown in fig. 1A and 2A, a base material 10 made of copper or a copper alloy is prepared. As the substrate 10, a pure copper-based substrate such as oxygen-free copper or tough pitch copper, or a substrate made of a copper alloy such as brass, phosphor bronze, Cu-Ni-Si-based alloy, Cu-Fe-P-based alloy, or Cu-Ni-Sn-P-based alloy can be used. The shape of the base material 10 may be a long single piece, but is preferably a strip-shaped material (from which a plating material can be produced by a continuous plating line in a roll-to-roll manner) from the viewpoint of productivity.

Next, as shown in fig. 1B and 2B, a nickel plating film 12 is formed as a base plating film on substantially the entire surface (rolling surface) of the base material 10. The nickel plating film may be formed by either electroplating or electroless plating, and is preferably formed by electroplating from the viewpoint of productivity and cost.

Next, as shown in fig. 1C and 2C, after disposing a mask member 14 (for example, attaching a mask tape or forming a resist mask) on a portion other than a portion of the surface of the nickel plating film 12 so as to cover the portion, as shown in fig. 1D and 2D, a silver plating film 16 is formed on a portion of the surface of the nickel plating film 12 (a region where the mask member 14 is not disposed (a region other than the region indicated by oblique lines in fig. 1C and 1D)), and then, as shown in fig. 1E and 2E, the mask member 14 is removed (for example, the mask tape or the resist mask is peeled). The formation of the silver plating film 16 is preferably performed by electroplating.

Next, as shown in fig. 1F and 2F, after a mask member 18 is disposed (for example, a mask tape is attached or a resist mask is formed) so as to cover (the entire surface of) a portion other than a portion of the surface of the nickel plating film 12 and the surface of the silver plating film 16, as shown in fig. 1G and 2G, a tin plating film 20 is formed on a portion other than the portion of the surface of the nickel plating film 12 (a region where the mask member 18 is not disposed (a region other than the region indicated by oblique lines in fig. 1F and 1G)), and then, as shown in fig. 1H and 2H, the mask member 18 is removed (for example, the mask tape or the resist mask is peeled). The formation of the tin plating film 20 is preferably performed by electroplating.

After a plating material in which a silver plating film 16 and a tin plating film 20 (spaced apart from the silver plating film 16) are formed on the surface of the nickel plating film 12 formed on substantially the entire surface of the base 10 is thus produced, the plating material is preheated in a furnace using a ceramic plate heater or the like without melting the tin plating film 20, and then, as shown in fig. 1J and 2J, the surface of the plating material is heated by irradiating infrared rays (using an infrared lamp or the like) in the atmosphere to melt the tin plating film 20 and then cooled (reflow treatment), thereby forming the tin plating film 20 into a reflowed tin plating layer 22.

In addition, heating by infrared rays is radiation, and silver is less likely to absorb infrared rays, and its absorptivity is about 0.01 at a wavelength of 1 μm, for example, whereas tin is more likely to absorb infrared rays, and its absorptivity is about 0.25 at a wavelength of 1 μm, for example. Therefore, it is considered that when a plating material having the silver plating film 16 and the tin plating film 20 formed on the surface of the nickel plating film 12 formed substantially over the entire surface of the base 10 is heated by irradiation with infrared rays using an infrared lamp or the like, the silver plating film 16 is hardly heated by radiation, the tin plating film 20 is selectively heated, the tin plating film 20 is cooled (reflow treatment) after being melted, and the tin plating film 20 becomes the reflow tin plating layer 22. Thus, when the reflow tin plating layer 22 is formed, it is considered that the temperature rise of the silver plating film due to heating is suppressed, so that the discoloration of the silver plating film is suppressed, and the increase in contact resistance is also suppressed. Further, if preheating is performed before heating by infrared rays to such an extent that the tin plating film is not melted, the time for heating by infrared rays can be shortened.

When the substrate 10 is a strip material, it is preferable to perform continuous plating by a roll-to-roll continuous plating line. In the case of using a mask tape as the mask member 18, it is preferable to continuously attach the mask tape by a continuous tape attaching device in the continuous plating line.

The following embodiments of the plating material of the present invention can be produced by the above-described embodiments of the method for producing a plating material.

In an embodiment of the plating material of the present invention, a nickel plating layer 12 is formed on substantially the entire surface of a base material 10 made of copper or a copper alloy, a silver plating layer 16 is formed on a part of the surface of the nickel plating layer 12, and a reflow tin plating layer 22 is formed on a part of the other part of the surface of the nickel plating layer 12 (so as to be spaced apart from the silver plating layer 16), and the contact resistance of the surface of the silver plating layer 16 is 1m Ω or less.

Examples

Hereinafter, examples of the plating material and the method for producing the same according to the present invention will be described in detail.

[ examples ]

First, as a base material (plating target material), a strip material made of a Cu — Ni — Sn alloy (NB 109-EH material manufactured by seikagaku corporation) having a thickness of 0.2mm and a width of 25mm was prepared, and the strip material was set (subjected to continuous plating) in a roll-to-roll continuous plating line so that the width direction of the strip material was perpendicular.

In this continuous plating line, as pretreatment of the material to be plated, the material to be plated and the SUS plate were put into an alkaline degreasing solution, electrolytic degreasing was performed at 5V for 30 seconds with the material to be plated as a cathode and the SUS plate as an anode, and after washing with water, pickling was performed in 3% sulfuric acid for 15 seconds.

Then, in the continuous plating line, the plating solution was formed by plating a layer containing 540g/L nickel sulfamate tetrahydrate and 25g/L nickel sulfamate tetrahydrateIn a matte nickel plating solution comprising an aqueous solution of nickel chloride and 35g/L boric acid, a material to be plated subjected to pretreatment is used as a cathode, a nickel piece accommodated in a titanium anode casing is used as an anode, and the plating solution is heated at a solution temperature of 50 ℃ and a current density of 9A/dm²Plating (matte nickel plating) was performed for 30 seconds, and matte nickel plating films were formed as base plating films on substantially the entire surfaces of both surfaces of the plating target material. The thickness of the matte nickel plating film at the substantially center portion in the width direction was measured by a fluorescent X-ray film thickness meter (SFT-110A manufactured by Hitachi high-tech science, Ltd. (Hitachi ハイテクサイエンス)), and was 0.5. mu.m.

Then, in the continuous plating line, mask tapes were attached to the both surfaces of the base material (material to be plated) at a portion having a width of 13mm from the lower end in the width direction and at a portion having a width of 4mm from the upper end in the width direction.

Next, in a continuous plating line, in a strike silver plating solution formed from an aqueous solution containing 3g/L potassium silver cyanide and 90g/L potassium cyanide, a base material on which a base plating film is formed is made a cathode, a stainless steel (SUS) plate is made an anode, and the plating solution is passed through a bath at room temperature (25 ℃ C.) at 2A/dm²The plating was performed for 10 seconds at the current density of (1), and after a strike silver plating film was formed on the base material on which the base plating film was formed in the region (strip-shaped exposed surface) to which no masking tape was attached, the base plating film was washed with water to completely remove the strike silver plating solution.

Then, in the continuous plating line, the plating solution was continuously plated in a continuous plating line containing 175g/L of silver potassium cyanide (KAg (CN)₂) In a silver plating solution comprising an aqueous solution of 95g/L potassium cyanide (KCN) and 102mg/L potassium selenocyanate, the substrate on which the strike silver plating film was formed was used as the cathode, the silver particles contained in the titanium anode case were used as the anode, and the plating solution was heated at a temperature of 18 ℃ and a plating solution temperature of 8A/dm²The current density of (1) was subjected to plating (silver plating) for 21 seconds to form a silver plated film on (the strike silver plated film on) the substrate, and water washing was performed to thoroughly wash off the silver plating solution. The thickness of the silver plating film at the substantially central portion in the width direction was measured by a fluorescent X-ray film thickness meter (SFT-110A manufactured by Hitachi high-tech science Co., Ltd.), and it was 1.0. mu.m.

Next, in the continuous plating line, after the mask tape was peeled off from the base plating film on the base material, the mask tape was attached to a portion (the entire surface of the silver plating film and a band-shaped portion covering a part of the base plating film) of the base material having a width of 15mm from the end in the width direction.

Next, in a continuous plating line, in a tin plating solution containing 250mL/L of tin alkanol sulfonate (メタス SM-2 manufactured by YOU SANKO Co., Ltd.) (as a metallic tin salt) and 75mL/L of tin alkanol sulfonate (メタス AM manufactured by YOU SANKO Co., Ltd.) (as a free acid), a substrate on which a silver plating film was formed was used as a cathode, a tin ball contained in a titanium anode can was used as an anode, and 12A/dm was set at a liquid temperature of 25 ℃ C²The current density of (2) was subjected to electroplating (tin plating) for 14 seconds to form a tin plating film having a thickness of 1 μm on a region of the substrate to which the mask tape was not attached (an exposed surface of the base plating film on the substrate (a region of 10mm from the lower end of the plating target material in the width direction)), and then the mask tape was peeled off.

Next, the substrate on which the tin plating film was formed was placed in a furnace using a ceramic plate heater, preheated in the furnace (the tin plating film was not melted during the preheating), and then heated for 15 seconds at an output of 67% for reflow treatment by facing a flat-panel radiation type infrared lamp (Ps 110VP, single layer 200V, 2kW, manufactured by ADVANCE inc., ltd., アドバンス zeuginessman). By this reflow treatment, the tin plating layer was melted and solidified, and it was confirmed that a reflow tin plating layer was formed.

The plating material thus prepared had a contact resistance of the surface of the silver plating layer measured by an electric contact simulator (CRS-1, manufactured by kazaki seiko corporation) at a load of 100gf before and after the reflow treatment, and as a result, the contact resistance was 0.72m Ω before the reflow treatment and 0.64m Ω after the reflow treatment, and the contact resistance was not increased. Further, the appearance of the silver plating layer was visually observed, and it was confirmed that the color was not changed before and after the reflow treatment.

[ comparative example ]

A plating material was produced in the same manner as in example except that the base material on which the tin plating film was formed was placed on a hot plate (HIGH TEMP hot plate (model number HTH-500N) manufactured by shiitang corporation, アズワン), and heated at 450 ℃ in the atmosphere, instead of heating the base material on which the tin plating film was formed by a flat panel-shaped radiation type infrared lamp after preheating.

As a result of measuring the contact resistance of the surface of the silver plating layer before and after the reflow treatment in the same manner as in example, the plating material thus produced was 0.75m Ω before the reflow treatment and 2.49m Ω after the reflow treatment, and the contact resistance was significantly increased. Further, the appearance of the silver plating layer was visually observed, and as a result, it was confirmed that discoloration occurred before and after the reflow treatment.

Description of the symbols

10 base material

12 substrate coating (Nickel coating)

14 mask member

16 silver plating film

18 mask member

20 tin plating film

The tin plating is reflowed 22.