JPWO2018221087A1 - PCB terminal - Google Patents

Abstract

(EN) Provided is a PCB terminal which has excellent wear resistance, electrical conductivity, slidability and low friction, and which can reduce the amount of expensive gold used. A comb-tooth-shaped PCB terminal having a plurality of substantially square pole-shaped male terminals (4), which has a nickel plating layer (12) on the entire surface of the male terminal (4) and is provided on the surface of the nickel plating layer (12). Having a gold plating layer (14) with a thickness of 0.2 μm to 1.0 μm, and the dynamic friction coefficient of the gold plating layer with respect to high carbon chromium bearing steel (SUJ2) is less than 0.2. PCB terminal.

Description

  The present invention relates to a PCB terminal, and more particularly to a PCB terminal having excellent wear resistance, electrical conductivity, slidability and low friction, and excellent durability.

  PCB terminals are used in various connectors for in-vehicle use, consumer use, etc., and are essential for mounting printed circuit boards. In general, a plurality of terminals are arranged in a comb shape by punching out a flat sheet-shaped metal substrate.

  Further, in order to realize a good electrical contact, the PCB terminal is required to have excellent electrical conductivity and abrasion resistance, and the tip of the male terminal fitted with the female terminal may be surface-treated. Many. For example, Patent Document 1 (Japanese Patent Laid-Open No. 2008-287942) proposes a PCB connector terminal having an outermost surface plated with Sn.

  In the PCB connector terminal described in Patent Document 1, since the friction coefficient of the fitting portion can be 0.26 or less and the zero cross time after aging of the soldering portion can be 5 seconds or less, insertion into the connector It is said that it is possible to provide a PCB terminal and a method for manufacturing the same that are excellent in reducing the insertion force and improving the solder wettability of the soldered portion to the board side.

  Further, in Patent Document 2 (Japanese Patent Laid-Open No. 10-41027), to solve the problem of providing a surface mount contact pin that has a simple structure and can be manufactured at low cost, excessive solder is received/accommodated from a pad or a land. Surface mount connector pins for printed circuit boards have been proposed that are removed into the means, and one form of such surface mount connector pins is shown where the surface is gold plated.

JP, 2008-287942, A JP, 10-41027, A

  However, although the PCB terminal described in Patent Document 1 has improved sliding characteristics and solder wettability, the outermost surface is a tin-plated layer, and the electrical conductivity, durability, and the like in comparison with a gold-plated layer. Not enough.

  Further, in the surface mount connector pin described in Patent Document 2, the characteristics of the gold plating layer suitable for the PCB terminal have not been studied at all. In addition, no consideration is given to the durability when the PCB terminal is repeatedly used.

  In view of the problems in the prior art as described above, an object of the present invention is to provide a PCB terminal having excellent wear resistance, electrical conductivity, slidability and low friction, and having sufficient durability. To do.

  In order to achieve the above object, the present inventor has conducted earnest research on a gold plating layer to be formed on the surface of a PCB terminal, and as a result, it is extremely possible to control the dynamic friction coefficient and the like while ensuring the adhesion to the base material. They have found that it is effective and have reached the present invention.

That is, the present invention is
A comb-tooth-shaped PCB terminal having a plurality of substantially square-pillar-shaped male terminals,
Having a nickel plating layer on the entire surface of the male terminal,
The surface of the nickel plating layer has a gold plating layer having a thickness of 0.2 μm to 1.0 μm,
The dynamic friction coefficient of the gold plating layer with respect to high carbon chromium bearing steel (SUJ2) is less than 0.2;
A PCB terminal is provided.

  In the PCB terminal of the present invention, since the outermost surface of the male terminal, which contributes to the conduction when fitted with the female terminal, is the gold plating layer, sufficient electrical conductivity can be ensured. Also, by setting the thickness of the gold plating layer to 0.2 μm or more, the electrical characteristics and durability of gold can be fully utilized, and by setting it to 1.0 μm or less, the amount of gold used can be suppressed. In addition to that, it is possible to suppress deterioration of productivity. The thickness of the gold plating layer is more preferably 0.4 μm to 0.8 μm, and most preferably 0.5 μm to 0.7 μm.

  Further, a nickel plating layer is formed between the metal base material of the male terminal and the gold plating layer, and the nickel plating layer causes an intermetallic compound accompanying diffusion and reaction between the element contained in the metal base material and gold. It is possible to suppress the embrittlement of the gold plating layer due to the formation of.

  The thickness of the nickel plating layer is preferably 0.3 μm to 4.0 μm. By setting the thickness of the nickel plating layer to 0.3 μm or more, it is possible to reliably suppress the embrittlement of the gold plating layer due to the formation of intermetallic compounds due to the diffusion and reaction of the element contained in the metal base material with gold. When the thickness is 4.0 μm or less, it is possible to suppress deterioration of conductivity and mechanical properties due to the presence of the nickel plating layer. The thickness of the nickel plating layer is more preferably 0.4 μm to 2.0 μm, and most preferably 0.5 μm to 1.5 μm.

  Further, in the PCB terminal of the present invention, regarding the gold plating layer formed on the outermost surface, the dynamic friction coefficient of the gold plating layer with respect to the high carbon chromium bearing steel (SUJ2) is less than 0.2. When the dynamic friction coefficient of the gold plating layer is less than 0.2, the resistance at the time of inserting and removing the male terminal can be appropriately reduced, and damage to the male terminal and the female terminal due to wear can be suppressed. it can. The measurement of the dynamic friction coefficient is not particularly limited, and various conventionally known measurement methods can be used.

  Further, in the PCB terminal of the present invention, it is preferable that the gold plating layer has a Vickers hardness of 150 HV to 250 HV. By setting the Vickers hardness to 150 HV or more, the durability of the PCB terminal can be improved, and by setting it to 250 HV or less, damage to the female terminal due to sliding of the male terminal and the female terminal can be suppressed.

  Further, in the PCB terminal of the present invention, it is preferable that the gold plating layer has a cobalt concentration of 0.1% by mass to 1% by mass. By setting the cobalt concentration to 0.1% by mass to 1% by mass, the Vickers hardness and the dynamic friction coefficient can be set within the above numerical ranges.

  Further, in the PCB terminal of the present invention, it is preferable that the gold plating layer is formed on the surface of the nickel plating layer via a gold flash plating layer having a thickness of more than 0 and not more than 0.1 μm. By forming the gold plating layer on the nickel plating layer via the gold flash plating layer, the adhesion between the gold plating layer and the nickel plating layer can be sufficiently ensured. As a result, even if the gold plating layer is not extremely thin, it is possible to prevent the gold plating layer from peeling off from the nickel plating layer.

  Further, in the PCB terminal of the present invention, the nickel plating layer is formed on the surface of the male terminal through a base strike plating layer, and the base strike plating layer is a copper strike plating layer or a nickel strike plating layer. It is preferable that at least one of them is formed. Since the nickel plating layer is formed on the metal base material via the underlying strike plating layer, the adhesion between the nickel plating layer and the metal base material can be sufficiently ensured.

  Further, in the PCB terminal of the present invention, it is preferable that the gold plating layer is formed only on the front surface side and the back surface side of the male terminal. Since the gold plating layer is formed on the front surface and the back surface of the male terminal, which is mainly in contact with the female terminal at the time of fitting, sufficient current-carrying characteristics can be ensured. On the other hand, a gold plating layer is not formed on both side surfaces of the male terminal that hardly contributes to the current-carrying characteristics, so that the amount of gold used is kept to a minimum.

  According to the PCB terminal of the present invention, it is possible to provide a PCB terminal having excellent wear resistance, electrical conductivity, slidability and low friction, and having sufficient durability.

It is a schematic perspective view which shows an example of the PCB terminal of this invention. It is an A-A' sectional view of the male terminal 4. It is process drawing of the manufacturing method of the PCB terminal of this invention.

Hereinafter, representative embodiments of the PCB terminal of the present invention and a method of manufacturing the PCB terminal will be described in detail with reference to the drawings, but the present invention is not limited thereto.
In the following description, the same or corresponding parts will be denoted by the same reference symbols, and redundant description may be omitted. Moreover, since the drawings are for conceptually explaining the present invention, the dimensions of each of the illustrated components and their ratios may differ from the actual ones.

<< PCB terminal >>
FIG. 1 is a schematic perspective view showing an example of a PCB terminal of the present invention. The PCB terminal 1 has a comb-like shape in which a plurality of substantially square pole-shaped male terminals 4 are arranged in parallel at the end of the metal base material 2. The PCB terminal 1 can be efficiently manufactured by using the PCB terminal manufacturing method of the present invention.

  Basically, the metal base material 2 and the male terminal 4 are made of the same material and are not particularly limited as long as they have electrical conductivity. For example, aluminum and aluminum alloys, iron and iron alloys (for example, iron-nickel alloy). , Titanium and titanium alloys, stainless steel, copper and copper alloys, and the like. Among them, it is preferable to use copper or brass because of their excellent electrical conductivity, thermal conductivity, and ductility.

  A sectional view of the male terminal 4 taken along the line A-A' is shown in FIG. In the male terminal 4, the nickel plating layer 12 is formed on the surface of the metal base material 2, and the gold plating layer 14 is formed on the surface of the nickel plating layer 12 via a gold flash plating layer (not shown). There is. By forming the gold flash plating layer, the adhesion between the nickel plating layer 12 and the gold plating layer 14 can be sufficiently ensured. As a result, even if the gold plating layer 14 is not extremely thin, it is possible to prevent the gold plating layer 14 from peeling off from the nickel plating layer 12.

  Although the gold plating layer 14 may be formed on the entire surface of the male terminal 4, it is preferably formed only on the front surface and the back surface of the male terminal 4 that contacts the female terminal. The gold flash plating layer may be formed on the entire surface of the nickel plating layer 12, or may be formed only on the front surface and the back surface of the male terminal 4 on which the gold plating layer 14 is formed.

  The thickness of the gold plating layer 14 is 0.2 μm to 1.0 μm. When the thickness of the gold plating layer 14 is 0.2 μm or more, the electrical characteristics and durability of gold can be fully utilized, and when it is 1.0 μm or less, the amount of gold used can be suppressed. In addition, productivity deterioration can be suppressed. The thickness of the gold plating layer 14 is more preferably 0.4 μm to 0.8 μm, and most preferably 0.5 μm to 0.7 μm.

  The thickness of the gold flash plating layer is preferably more than 0 and 0.1 μm or less. The thickness of the gold flash plating layer is more preferably 0.08 μm or less, and most preferably 0.06 μm or less. By setting the thickness of the gold flash plating layer to 0.1 μm or less, an increase in the amount of gold used and a deterioration in productivity can be suppressed.

  In the PCB terminal 1, since the gold plating layer 14 is formed on the surface of the male terminal 4 that comes into contact with the female terminal at the time of fitting, the gold plating layer 14 has excellent wear resistance, low electric resistance, and good wear resistance. The heat resistance can be utilized, and the conductivity and durability required for the PCB terminal can be sufficiently ensured. Furthermore, by not forming the gold plating layer 14 on both side surfaces of the male terminal 4 and forming the gold plating layer 14 only on the front surface and the back surface, the amount of gold used can be suppressed to a necessary minimum.

  The gold plating layer 14 has a dynamic friction coefficient of less than 0.2 with respect to the high carbon chromium bearing steel (SUJ2). When the coefficient of dynamic friction is less than 0.2, the resistance at the time of inserting/removing the male terminal 4 can be appropriately reduced, and damage to the male terminal 4 and the female terminal due to wear can be suppressed. . The measurement of the dynamic friction coefficient is not particularly limited, and various conventionally known measurement methods can be used, for example, HEIDON-14 manufactured by Shinto Scientific Co., Ltd. can be used for measurement.

  The Vickers hardness of the gold plating layer 14 is preferably 150HV to 250HV. By setting the Vickers hardness to 150 HV or higher, the durability of the PCB terminal 1 can be improved, and by setting it to 250 HV or lower, damage to the female terminal due to sliding between the male terminal 4 and the female terminal can be suppressed.

  The cobalt concentration of the gold plating layer 14 is preferably 0.1% by mass to 1% by mass. By setting the cobalt concentration to 0.1% by mass to 1% by mass, the Vickers hardness and the dynamic friction coefficient can be set within the above numerical ranges.

  In addition, in the PCB terminal 1, the nickel plating layer 12 is formed on the surface of the male terminal 4 via the underlying strike plating layer, and as the underlying strike plating layer, one of the copper strike plating layer and the nickel strike plating layer is used. It is preferable that at least one is formed. Since the nickel plating layer 12 is formed on the metal substrate 2 via the underlying strike plating layer, the adhesion between the nickel plating layer 12 and the metal substrate 2 can be sufficiently ensured.

  Further, in the PCB terminal 1, since the nickel plating layer 12 exists between the metal base material 2 and the gold plating layer 14, the nickel plating layer 12 prevents diffusion and reaction between the element contained in the metal base material 2 and gold. Function as a barrier layer. That is, the presence of the nickel plating layer 12 between the metal base material 2 and the gold plating layer 14 causes the formation of an intermetallic compound due to the diffusion and reaction of the element contained in the metal base material 2 and gold, Embrittlement of the plating layer 14 can be suppressed.

  The nickel plating layer 12 preferably has a continuous film shape, and the thickness of the nickel plating layer 12 is preferably 0.3 μm to 4.0 μm. If it is less than 0.3 μm, the barrier effect is poor, and if it exceeds 4 μm, cracks are likely to occur during bending. The thickness of the nickel plating layer 12 is more preferably 0.4 μm to 2.0 μm, and most preferably 0.5 μm to 1.5 μm. In addition, the nickel plating layer 12 may have a granular or island-shaped discontinuous film shape as long as the effect of the present invention is not impaired. In that case, the granular and island-shaped portions are partially continuous. Good.

  Furthermore, by forming the outermost surfaces of the front and back surfaces of the male terminal 4 where the sliding wear is remarkable, a serious accident such as ignition and electric shock due to the metal pieces scattered by the sliding wear is caused. Can be prevented.

<< PCB terminal manufacturing method >>
FIG. 3 is a process drawing of the method for manufacturing a PCB terminal of the present invention. In the PCB terminal 1, the gold plating layer 14 is formed on the outermost surface of the male terminal 4, but here, the gold plating layer 14 is formed only on the front surface and the back surface of the male terminal 4 that contacts the female terminal during use. A method of manufacturing the PCB terminal 1 will be described in detail. In the manufacturing method, the metal base material 2 in the shape of the PCB terminal 1 is nickel-plated to form a nickel plating layer 12 on the entire surface of the male terminal 4, and a front surface and a back surface of the male terminal 4. A second step (S02) of forming a masking layer on the first side, a third step (S03) of forming a resist layer on both side surfaces of the male terminal 4, and a first step of forming a gold plating layer 14 on the front and back surfaces of the male terminal 4. It is characterized by including four steps (S04). Hereinafter, each step will be described in detail.

(1) Pretreatment The metal base material 2 is processed into the shape of the PCB terminal 1 and has a comb-like shape having a plurality of substantially square pole-shaped male terminals 4. Here, the shape, size, number of terminals, and the like of the terminals are not particularly limited, and may be determined according to the requirements of the PCB terminal 1.

  The metal used for the metal substrate 2 is not particularly limited as long as it has electrical conductivity, and examples thereof include aluminum and aluminum alloys, iron and iron alloys (for example, iron-nickel alloys), titanium and titanium alloys, stainless steel, and copper. Examples thereof include copper alloys and the like. Among them, it is preferable to use copper or brass because of its excellent electrical conductivity, thermal conductivity and spreadability.

  Further, it is preferable to wash the metal base material 2 as a pretreatment for various plating treatments. The method for cleaning the metal substrate 2 is not particularly limited as long as the effects of the present invention are not impaired, and various conventionally known cleaning methods can be used. As the cleaning treatment liquid, for example, a general immersion degreasing liquid or an electrolytic degreasing liquid can be used.

(2) Base Strike Plating Treatment The base strike plating treatment is a preliminary treatment of the first step (S01), and is preferably performed when it is necessary to improve the adhesion between the metal base 2 and the nickel plating layer 12. .. As the base strike plating treatment, for example, copper strike plating treatment, nickel strike plating treatment, or the like can be used.

(A) Copper Strike Plating As the copper strike plating bath, for example, a bath containing a copper salt/conductive salt can be used. Further, a brightening agent may be added.

  As the copper strike plating bath that can be suitably used for the copper strike plating treatment, for example, a copper cyanide bath can be used. The copper cyanide bath is composed of a copper salt, an alkali cyanide salt and a conductive salt, and an additive or a brightening agent may be added.

  As the copper salt, for example, copper cyanide can be used. As the alkali cyanide salt, for example, potassium cyanide, sodium cyanide, or the like can be used. As the conductive salt, for example, potassium carbonate, sodium carbonate or the like can be used. As the additive, for example, Rochelle salt, potassium selenite, sodium selenite, potassium thiocyanate, lead acetate, lead tartrate or the like can be used.

The copper strike plating conditions such as the bath temperature of the copper strike plating bath, the anode material, and the current density can be appropriately set according to the plating bath used, the required plating thickness, and the like. For example, it is preferable to use a soluble anode such as electrolytic copper and/or an insoluble anode such as stainless steel, a titanium platinum plate, or iridium oxide as the anode material. As suitable plating conditions, bath temperature: 25 to 70° C., current density: 0.1 to 6.0 A/dm ² , and treatment time: 5 to 60 seconds can be exemplified.

(B) Nickel Strike Plating As the nickel strike plating bath, for example, one containing a nickel salt, an anodic dissolution accelerator and a pH buffer can be used. Further, an additive may be added to the nickel strike plating bath.

  As the nickel salt, for example, nickel sulfate, nickel sulfamate, nickel chloride or the like can be used. As the anodic dissolution promoter, for example, nickel chloride, hydrochloric acid or the like can be used. As the pH buffer, for example, boric acid, nickel acetate, citric acid, etc. can be used. Examples of additives include primary brighteners (saccharin, benzene, naphthalene (di, tri), sodium sulfonate, sulfonamide, sulfinic acid, etc.), secondary brighteners (organic compounds: butynediol, coumarin, allyl aldehyde). Sulfonic acid and the like, metal salts: cobalt, lead, zinc and the like), pit inhibitors (sodium lauryl sulfate and the like) and the like can be used.

  A suitable amount of each component of the nickel strike plating bath that can be suitably used for the nickel strike plating treatment is as follows: nickel salt: 100 to 300 g/L, anodic dissolution accelerator: 0 to 300 g/L, pH buffer: 0 to 50 g/L, additive: 0 to 20 g/L.

The nickel strike plating conditions such as the bath temperature of the nickel strike plating bath, the anode material, and the current density can be appropriately set depending on the plating bath used, the required plating thickness, and the like. For example, as the anode material, it is preferable to use a soluble anode such as electrolytic nickel, carbonized nickel, deposited nickel, and sulfa nickel. As suitable plating conditions, bath temperature: 20 to 30° C., current density: 1.0 to 5.0 A/dm ² , treatment time: 1 to 30 seconds, pH: 0.5 to 4.5 are exemplified. can do.

(3) Nickel plating treatment (first step (S01))
The nickel plating treatment forms the nickel plating layer 12 which functions as a barrier layer between the metal base material 2 and the gold plating layer 14 to prevent the diffusion and reaction of the element contained in the metal base material 2 and gold. Is a process performed on the. The presence of the nickel plating layer 12 between the metal base material 2 and the gold plating layer 14 causes the formation of an intermetallic compound due to the diffusion and reaction between the elements contained in the metal base material 2 and gold, thereby forming the gold plating layer Embrittlement can be suppressed.

  As the nickel plating bath, for example, a Watts bath or a sulfamic acid bath can be used, but a sulfamic acid bath having a low electrodeposition stress is preferably used. In addition, it is preferable to avoid a strong acid wood strike bath. For the nickel plating treatment, various conventionally known nickel plating techniques can be used within a range that does not impair the effects of the present invention. For example, a nickel plating bath is a solution composed of a nickel salt such as nickel sulfate, nickel sulfamate and nickel chloride, an anodic dissolving agent such as nickel chloride, and a pH buffering agent such as boric acid, acetic acid and citric acid. As an additive, a material to which a small amount of a brightening agent, a leveling agent, a pit preventing agent, etc. are added can be used. A suitable amount of each constituent used is nickel salt: 100 to 600 g/L, anodic dissolution agent: 0 to 50 g/L, pH buffer: 20 to 50 g/L, additive: to 5000 ppm.

The nickel plating conditions such as the bath temperature of the nickel plating bath, the anode material, and the current density can be appropriately set according to the plating bath used, the required plating thickness, and the like. For example, it is preferable to use a soluble anode such as a nickel plate as the anode material. Moreover, as suitable plating conditions, bath temperature: 40-60 degreeC, current density: 0.1-50 A/dm< ² >, pH: 3.0-5.0 can be illustrated.

  The nickel plating layer 12 formed by the nickel plating treatment in the first step preferably has a continuous film shape, and the thickness of the nickel plating layer 12 is preferably 0.3 μm to 4.0 μm. If it is less than 0.3 μm, the barrier effect is poor, and if it exceeds 4 μm, cracks are likely to occur during bending. The thickness of the nickel plating layer 12 is more preferably 0.4 μm to 2.0 μm, and most preferably 0.5 μm to 1.5 μm. The nickel plating layer 12 may have a granular or island-shaped discontinuous film shape as long as the effect of the present invention is not impaired. In that case, the particles and island-shaped portions are partially continuous. Good.

(4) Gold plating flash treatment The gold plating flash treatment is a treatment for the nickel plating layer 12 formed in the first step (S01), and is mainly a portion that is not the fitting portion (the gold plating layer 14 needs to be thickened). This is a process performed to give corrosion resistance to the non-existing part). Although there is no problem in the order of the steps of performing gold plating flash treatment after gold plating treatment, it is preferable to perform after gold plating from the viewpoint of adhesion. By forming a thin gold plating layer on the surface of the nickel plating layer 12, the adhesion between the gold plating layer 14 and the nickel plating layer 12 formed in the fourth step (S04) can be sufficiently secured.

  As the gold plating flash bath, for example, one containing a gold salt, a conductive salt, a chelating agent and a crystal growth agent can be used. Further, a brightener may be added to the gold plating flash bath.

  As the gold salt, for example, gold cyanide, potassium gold(I) cyanide, potassium gold(II) cyanide, gold(II) sulfite, gold(II) thiosulfate and the like can be used. As the conductive salt, for example, potassium citrate, potassium phosphate, potassium pyrophosphate, potassium thiosulfate and the like can be used. As the chelating agent, for example, ethylenediaminetetraacetic acid and methylenephosphonic acid can be used. As the crystal growth agent, for example, cobalt, nickel, thallium, silver, palladium, tin, zinc, copper, bismuth, indium, arsenic and cadmium can be used. As the pH adjuster, for example, polyphosphoric acid, citric acid, tartaric acid, potassium hydroxide, hydrochloric acid, etc. may be added.

  The suitable amount of each component of the gold plating flash bath that can be preferably used for the gold plating flash treatment is as follows: gold salt: 1 to 10 g/L, conductive salt: 0 to 200 g/L, chelating agent: 0 to 30 g /L, crystal growth agent: 0 to 30 g/L.

The gold plating flash conditions such as the bath temperature of the gold plating flash bath, the anode material, and the current density can be appropriately set according to the plating bath used, the required plating thickness, and the like. For example, a titanium platinum plate and an insoluble anode such as iridium oxide are preferably used as the anode material. Moreover, as suitable plating conditions, bath temperature: 20-40 degreeC, current density: 0.1-5.0 A/dm< ² >, processing time: 1-60 seconds, pH: 0.5-7.0 is illustrated. can do.

(5) Masking treatment (second step (S02))
The masking process is a process for forming a masking layer that prevents the formation of the resist layer in the third step (S03). Before the masking process, it is preferable to dry the metal substrate 2 that has been subjected to various plating processes with a dryer or the like. Here, in order to prevent the resist layer from being formed on the front surface and the back surface of the male terminal 4 in the third step (S03), it is necessary to perform a masking process on the front surface and the back surface of the male terminal 4.

  The masking method is not particularly limited as long as the effects of the present invention are not impaired, and various conventionally known masking methods can be used. Examples of the masking method include a tape, a sparger mask, a drum mask, a resist, a dry film resist, and an inkjet method, and it is preferable to perform masking by using one kind or a combination of two or more kinds thereof.

  In particular, when it is desired to form the resist layer only on the side surface of the base material, the surface may be masked with a tape or a drum mask in the first step, and the resist layer may be formed only in the side surface with the liquid resist in the second step. preferable.

(6) Formation of resist layer (third step (S03))
In the third step (S03), after the resist is applied, the masking formed in the second step is peeled off, and in the fourth step (S04), areas where the gold plating layer 14 is not desired to be formed (both sides of the male terminal 4) This is a step for forming a resist on.

  After removing the masking, the resist can be cured by exposing it with a UV light (a mercury lamp, a metal halide lamp, an LED, etc.).

  Note that there are negative resists, positive resists, electrodeposition resists, liquid resists, dry film resists, and the like, but it is preferable to use the negative resist that does not require a dark room in the plating tank.

(7) Gold plating (fourth step (S04))
The fourth step (S04) is a step for forming the gold plating layer 14 only on the front and back surfaces of the male terminal 4. By passing through the third step (S03), a resist layer is formed on both side surfaces of the male terminal 4, and the front surface and the back surface of the male terminal 4 are a nickel plating layer 12 or a thin gold plating layer formed by a gold plating flash process. Therefore, by performing the gold plating treatment in the fourth step (S04), the gold plating layer 14 can be formed only on the front surface and the back surface of the male terminal 4.

  The thickness of the gold plating layer 14 is preferably 0.2 μm to 1.0 μm. When the thickness of the gold plating layer 14 is 0.2 μm or more, the electrical characteristics and durability of gold can be fully utilized, and when it is 1.0 μm or less, the amount of gold used can be suppressed. In addition, productivity deterioration can be suppressed. The thickness of the gold plating layer 14 is more preferably 0.4 μm to 0.8 μm, and most preferably 0.5 μm to 0.7 μm.

  For the gold plating treatment, various conventionally known gold plating methods can be used within a range that does not impair the effects of the present invention. However, the gold salt concentration in the plating bath is higher than that of ordinary gold flash plating. It is preferable to lower the concentration of the conductive salt.

  As the gold plating bath that can be suitably used for the gold plating treatment, for example, one containing a gold salt, a conductive salt, a chelating agent and a crystal growth agent can be used. Further, a brightening agent may be added to the gold plating bath. A suitable amount of each component used is gold salt: 1 to 100 g/L, conductive salt: 10 to 300 g/L, chelating agent: -30 g/L, crystal growth material: -30 g/L, brightener: 50- It is 500 ppm.

  Gold salts include, for example, gold cyanide, potassium potassium cyanide, potassium diammonium cyanide, sodium gold bisulfite, and sodium gold thiosulfate, and examples of conductive salts include potassium citrate and phosphorus. Examples thereof include potassium acid salt, potassium pyrophosphate and potassium thiosulfate.

  As the chelating agent, for example, ethylenediaminetetraacetic acid and methylenephosphonic acid can be used. As the crystal growth agent, for example, cobalt, nickel, thallium, silver, palladium, tin, zinc, copper, bismuth, indium, arsenic and cadmium can be used. As the pH adjuster, for example, polyphosphoric acid, citric acid, tartaric acid, potassium hydroxide, hydrochloric acid, etc. may be added.

The gold plating conditions such as the bath temperature of the gold plating bath, the anode material, and the current density can be appropriately set according to the plating bath used, the required plating thickness, and the like. For example, as the anode material, it is preferable to use stainless steel, a titanium platinum plate, an insoluble anode such as iridium oxide, or the like. Moreover, as suitable plating conditions, bath temperature: 20 to 50° C., current density: 0.1 to 5.0 A/dm ² , treatment time: 1 to 1440 seconds, pH: 3.0 to 7.0 are exemplified. can do.

  Here, the gold plating layer 14 has a dynamic friction coefficient of less than 0.2 with respect to the high carbon chromium bearing steel (SUJ2). The Vickers hardness of the gold plating layer 14 is preferably 150HV to 250HV. On the other hand, for example, by setting the cobalt concentration of the gold plating layer 14 to 0.1% by mass to 1% by mass, the Vickers hardness and the dynamic friction coefficient can be set within the numerical range.

  The representative embodiments of the present invention have been described above, but the present invention is not limited to these, and various design changes are possible, and all the design changes are included in the technical scope of the present invention. Be done.

<<Example>>
As a pretreatment, a copper-made metal base material in the shape of a comb-teeth-shaped PCB terminal having a plurality of substantially square-pillar-shaped male terminals is put into an alkaline degreasing liquid with a material to be plated and a SUS plate, and a material to be plated is used as a cathode. Using a SUS plate as an anode, electrolytic degreasing is performed at a voltage of 3 V for 30 seconds, and after washing, a copper strike plating bath containing 30 g/L cuprous blue bromide, 20 g/L free potassium bromide, and 15 g/L caustic potash. By using an electrolytic copper plate as the anode material and a metal substrate after the cleaning treatment as the cathode material, and performing a copper strike plating process (base strike plating process) for 10 seconds under conditions of bath temperature: 35° C., current density: 1 A/dm ^2. gave.

Then, using a nickel plating bath containing 300 g/L nickel sulfamate, 5 g/L nickel chloride hexahydrate, 10 g/L boric acid, and 0.2 g/L sodium lauryl sulfate, the anode material was formed. A sulfa nickel plate and a cathode material are used as a metal substrate after copper strike plating, and nickel plating is applied for 200 seconds under conditions of bath temperature: 50° C. and current density: 2 A/dm ² , and the entire surface of the terminal is about 1 μm thick. A nickel plating layer was formed (first step).

Then, using a gold plating bath containing 10/L potassium gold cyanide, 50 g/L potassium citrate, 10 g/L potassium hydroxide, 2 g/L cobalt sulfate, the anode material was a titanium platinum plate, and the cathode material was a cathode material. As a metal substrate after nickel plating is subjected to gold plating flash treatment for 2 seconds at a bath temperature of 40° C. and a current density of 0.5 A/dm ² , and a gold layer having a thickness of 0.1 μm is formed on the entire surface of the nickel plating layer. A plating flash layer was formed. Next, after the metal base material to be plated was dried using a dryer, the front surface and the back surface of the male terminal were masked with a masking tape (second step).

  Next, using a negative electrodeposition resist, a resist was applied for 30 seconds at a bath temperature of 35° C. and a constant voltage of 30V. After that, the masking tape was peeled off, and the resist was cured by exposing with a UV light (mercury lamp) for 100 seconds (third step). The heat generated during resist exposure was quickly removed by air cooling.

Then, in order to prevent the resist from peeling off, a cleaning process was performed using an immersion process instead of an electrolytic process. After the cleaning treatment, a gold plating bath containing 3 g/L of potassium gold cyanide, 120 g/L of potassium citrate, 50 g/L of potassium hydroxide and 100 ppm of cobalt sulfate was used, and the anode material was a titanium platinum plate. By subjecting the cathode material as a material to be plated after resist treatment, gold plating treatment is performed under conditions of bath temperature: 40° C. and current density: 1 A/dm ² for 30 seconds, and the resist is stripped using a stripping solution. A gold plating layer having a thickness of 0.5 μm was formed only on the front and back surfaces of the terminal (fourth step) to obtain a PCB terminal which is an example of the present invention.

[Evaluation]
(1) Evaluation of Adhesion Adhesion was evaluated for the plated laminate manufactured as described above. Cellophane tape (#405 manufactured by Nichiban Co., Ltd.) was pressed against the gold-plated layer by finger pressure, and after peeling off the cellophane tape, the gold-plated layer did not peel or swell. The obtained results are shown in Table 1.

(2) Evaluation of cross-cut adhesiveness After cutting in a grid pattern at a cut interval of 1 mm (cross-cut test), cellophane tape (#405 manufactured by Nichiban Co., Ltd.) was pressed against the gold plating layer with finger pressure, and The results obtained are shown in Table 1 when the peeling or swelling of the gold plating layer did not occur after the cellophane tape was peeled off, and when the gold plating layer did not swell.

(3) Measurement of Hardness of Gold Plating Layer With respect to the plated material produced as described above, the hardness of the gold plating layer on the outermost surface was measured using a micro Vickers hardness meter. The obtained results are shown in Table 1.

(4) Measurement of dynamic friction coefficient of gold plating layer The dynamic friction coefficient of the plated material prepared as described above was measured using HEIDON-14 manufactured by Shinto Scientific Co., Ltd. The measurement conditions were vertical load: 100 gf, moving distance: 5 mm, moving speed: 60 mm/min, sampling frequency: 500 Hz, mating material (steel ball): 3/8 inch SUJ2. The obtained results are shown in Table 2.

(5) Measurement of wear depth and wear width With respect to the sample after measurement in (4), the depth and width of wear scratches formed on the base material (plating material) side by sliding of the steel balls were measured. A laser microscope was used for the measurement. The obtained results are shown in Table 2.

(6) Measurement of Cobalt Concentration of Gold Plating Layer The cobalt concentration (eutectoid rate) of the gold plating layer was measured for the plated laminate produced as described above. A high-frequency plasma emission spectrometer (SPS5000) manufactured by Seiko Instruments Inc. was used for the measurement. The obtained results are shown in Table 2.

<<Example 2>>
A PCB terminal was prepared and various evaluations were performed in the same manner as in Example 1 except that the current density of the gold plating treatment in the fourth step was 3 A/dm ² . The obtained results are shown in Tables 1 and 2.

<<Example 3>>
A PCB terminal was prepared and various evaluations were performed in the same manner as in Example 1 except that the amount of potassium gold cyanide used for the gold plating treatment in the fourth step was 6 g/L. The obtained results are shown in Tables 1 and 2.

<<Example 4>>
A PCB terminal was prepared and various evaluations were performed in the same manner as in Example 1 except that 150 ppm of cobalt sulfate was used for the gold plating treatment in the fourth step. The obtained results are shown in Tables 1 and 2.

<<Comparative Example 1>>
A PCB terminal was prepared in the same manner as in Example 1 except that the cobalt concentration in the gold plating treatment in the fourth step was set to 0 ppm, and various evaluations were performed. The obtained results are shown in Tables 1 and 2.

  From the results shown in Table 1, it can be seen that the gold plating layer has excellent adhesion to all the PCB terminals obtained in Examples 1 to 4. Further, the Vickers hardness of the gold plating layer is in the range of 150 HV to 250 HV, and has an appropriate hardness. On the other hand, the PCB terminal obtained in Comparative Example 1 uses the same manufacturing conditions as those of the Example except for the gold plating treatment, so that there is no problem with respect to the adhesion of the gold plating layer, but the Vickers hardness is 106.7 HV. And low value. Here, from the results shown in Table 2, it is understood that the cobalt concentration of the gold plating layer of the example is within the range of 0.1% by mass to 1% by mass.

  Further, from the results shown in Table 2, for all the PCB terminals obtained in Examples 1 to 4, the dynamic friction coefficient of the gold plating layer with respect to the high carbon chromium bearing steel (SUJ2) is less than 0.2. .. On the other hand, the dynamic friction coefficient of the PCB terminal obtained in Comparative Example 1 is 1.37, which is about 10 times higher than that of the PCB terminal obtained in the Example.

  In addition, due to the difference in hardness and dynamic friction coefficient of the gold plating layer, the PCB terminal obtained in the example and the PCB terminal obtained in the comparative example are greatly different in wear depth and width. Specifically, as shown in Table 2, the abrasion damage of the PCB terminal obtained in the example is extremely shallow and the width thereof is also small. From these results, it can be confirmed that in the example, the PCB terminal having excellent wear resistance, slidability and low friction, and having sufficient durability was obtained.

1... PCB terminal,
2... Metal substrate
4... Male terminal,
12... Nickel plating layer,
14... Gold plating layer.

Claims (7)

A comb-teeth-shaped PCB terminal having a plurality of substantially square-pillar-shaped male terminals,
Having a nickel plating layer on the entire surface of the male terminal,
The surface of the nickel plating layer has a gold plating layer having a thickness of 0.2 μm to 1.0 μm,
The dynamic friction coefficient of the gold plating layer with respect to high carbon chromium bearing steel (SUJ2) is less than 0.2;
PCB terminal characterized by. Vickers hardness of the gold plating layer is 150 HV to 250 HV,
The PCB terminal according to claim 1, wherein: The cobalt concentration of the gold plating layer is 0.1% by mass to 1% by mass,
The PCB terminal according to claim 1 or 2, wherein. The gold plating layer is formed on the surface of the nickel plating layer via a gold flash plating layer having a thickness of more than 0 and 0.1 μm or less,
The PCB terminal according to any one of claims 1 to 3, characterized in that: The thickness of the nickel plating layer is 0.3 μm to 4.0 μm,
The PCB terminal according to any one of claims 1 to 4, characterized in that: The nickel plating layer is formed on the surface of the male terminal through a base strike plating layer,
As the underlying strike plating layer, at least one of a copper strike plating layer or a nickel strike plating layer is formed,
The PCB terminal according to any one of claims 1 to 5, characterized in that: The gold plating layer is formed only on the front surface side and the back surface side of the male terminal,
The PCB terminal according to any one of claims 1 to 6, characterized in that: