JPWO2020017389A1 - Coating materials and their manufacturing methods, composite materials, and terminals for electrical contacts - Google Patents

Abstract

The coating material (3) according to the present invention includes a metal (5) that can be electroplated and an organic fiber (2) having carbon and oxygen arranged in a dispersed state in the metal (5). However, on any surface of the coating material (3), the average area ratio of the organic fiber (2) in the observation field defined in the range of 100,000 μm 2 is in the range of 2.5% or more and 35% or less.

Description

The present invention relates to a coating material capable of improving sliding characteristics while suppressing a decrease in conductivity inherent in the metal itself as much as possible, a method for producing the same, and a composite material having the coating material and terminals for electrical contacts. Regarding.

In general, metal materials are widely used in various applications because they have excellent material properties such as conductivity. For example, a metal material in which a plating layer made of precious metals such as silver (Ag) and tin (Sn) is provided on a copper plate has excellent conductivity and strength of the base material and good electrical contact of the plating metal. As a high-performance conductor that combines characteristics, it is widely used in various electrical contact materials such as contacts, switches, and terminals.

On the other hand, it is desirable that the electrical contact material that undergoes repeated insertion / removal and sliding has excellent sliding characteristics (wear resistance). In order to greatly improve the sliding characteristics of such an electrical contact material, a composite material in which a dissimilar material having high strength such as carbon nanotube (CNT) is incorporated into a metal structure is known (Patent Document 1). However, CNTs having a large aspect ratio are exposed as protrusions on the surface of the composite material containing CNTs. Therefore, when such a composite material is used as an electrical contact material, it may cause a local temperature rise due to current concentration due to a small contact area.

Further, since CNTs are hydrophobic, it is often difficult to uniformly mix and disperse them with other substances and solvents constituting the composite material unless surface modification treatment is performed when the composite material is produced. In addition, it has been reported that heating a composite material containing such CNTs to a high temperature emits toxic substances having carcinogenicity, which poses an environmental problem.

Patent Document 2 discloses a conductive article in which organic polymer fibers are dispersed in a metal material formed by plating. However, although Patent Document 2 discloses a negative electrode material for a lithium secondary battery as an application of this conductive article, it does not mention its application as an electrical contact material, and also mentions sliding characteristics. It has not been. Further, the mass ratio of the organic polymer contained in the conductive article is as high as 20 to 90% by mass, and the conductivity, which is important as an electric contact material, becomes small, so such a composite material is not suitable as a contact material. it is conceivable that.

Patent Document 3 discloses a method of controlling the size of a metal material composited with cellulose. However, with this method, it is not possible to obtain a composite material having strength that can withstand processing into a shape required as an electrical contact material.

Japanese Unexamined Patent Publication No. 2007-09333 Japanese Unexamined Patent Publication No. 2008-293883 International Publication No. 2015/170613

In view of the above circumstances, the present invention provides a coating material having improved sliding characteristics, a method for producing the same, and a composite material having the same and terminals for electrical contacts while suppressing a decrease in conductivity inherent in the metal itself as much as possible. The purpose is to provide.

When electroplating (dispersion plating) is performed in a plating solution in which carbon and oxygen-containing organic fibers, particularly cellulose fibers, are dispersed, the present inventors cause changes in characteristics such as thermal decomposition of the organic fibers. It was found that it can be dispersed in the matrix metal without any problem. Then, by dispersing a certain amount of organic fibers in the matrix metal and controlling the ratio of the organic fibers exposed on the material surface, the coefficient of dynamic friction on the material surface is reduced, the sliding characteristics are improved, and the conductivity is improved. We found that the decrease in the rate could be suppressed as much as possible.

An aspect of the present invention is a coating material having an electroplatable metal and organic fibers having carbon and oxygen arranged in a dispersed state in the metal, and any surface of the coating material. In the film material, the average area ratio of the organic fibers to the observation field defined in the range of 100,000 μm ^{2 is in the range of 2.5% or more and 35% or less.}

An aspect of the present invention is a coating material in which at least one of the ^{organic fibers is present in a range of 10,000 μm 2 or less on an arbitrary surface of the coating material.}

An aspect of the present invention is a film material having an average area ratio of 2.5% or more and 25% or less.

An aspect of the present invention is a coating material in which the average mass ratio of the fibers of the organic substance contained in the coating material is 0.02% by mass or more and 10% by mass or less.

An aspect of the present invention is a film material having an average thickness of the film material of 500 μm or less.

An aspect of the present invention is a coating material in which the metal is Cu, Ag, Au, Sn, Ni or Pd.

An aspect of the present invention is a coating material in which the pre-organic substance is a cellulose fiber.

In aspects of the present invention, the metal is Cu, Ag or Sn, the average area ratio is 2.5% or more and 25% or less, the organic fiber is a cellulose fiber, and the coating material is optional. It is a coating material present at least one in the range of ^{1000 μm 2} or less on the surface of the above.

In an embodiment of the present invention, in a reciprocating sliding test in which a steel ball is used as a slider on the surface of the coating material with a load of 100 gf, the maximum dynamic friction coefficient under the condition that the number of sliding times is within the range of 20 to 50 times. It is a coating material whose value is 0.8 or less based on the metal itself.

An aspect of the present invention is a composite material having a base material and the coating material formed on the surface of the base material.

An aspect of the present invention is a composite material in which the base material is a conductive base material.

An aspect of the present invention is a composite material in which the base material is an insulating base material.

An aspect of the present invention is an electrical contact terminal provided with the coating material.

An aspect of the present invention is a method for producing the coating material formed by an electroplating method.

According to the present invention, on an arbitrary surface of a coating material having an electroplatable metal and organic fibers having carbon and oxygen arranged in a dispersed state in the metal, a predetermined observation region is formed. By controlling the average area ratio of organic fibers to a specific range, a coating material with improved sliding characteristics (wear resistance) while suppressing the decrease in conductivity inherent in the metal itself as much as possible, and a coating material thereof. It is possible to provide a composite material having. Further, since the coating material exhibiting such characteristics can be produced by an electroplating method, it can be easily and inexpensively produced. Furthermore, by using such a coating material for the terminals for electrical contacts, it is possible to form electrical contacts with improved sliding characteristics while maintaining the high electrical conductivity of the metal material, and as a result, the sliding of the contacts It is possible to suppress failures caused by motion and improve product life.

FIG. 1 is a schematic cross-sectional perspective view showing the distribution of organic fibers contained in a metal film when the film material according to the present invention is formed as a surface-treated film of a composite material. FIG. 2 is an example of data obtained when element mapping was performed on the film material obtained in Example 4, and FIG. 2 (a) shows the element distribution of the acquired carbon and oxygen. FIG. 2B shows image data of carbon and oxygen obtained by further binarizing by a discriminant analysis method.

Hereinafter, embodiments of the coating material and the composite material according to the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an example of an embodiment of the coating material and the composite material of the present invention. As shown in FIG. 1, the coating material 3 of the present embodiment has a metal (matrix metal) 5 and organic fibers 2 arranged in a dispersed state in the metal 5, and has a predetermined amount of organic fibers. 2 is exposed on the surface of the film material 3. Further, the composite material 1 of the present embodiment has a base material 4 and a coating material 3 formed on the surface of the base material 4. In FIG. 1, the organic fiber 2 is shown in a circular or elliptical shape for convenience.

<Organic fiber>
The organic fiber is an organic fiber having carbon and oxygen, and is preferably a fiber derived from a living body. Here, the organic substance means a polymer material obtained by repeating a unit structure a plurality of times among compounds containing carbon and oxygen, and is preferably a polymer material derived from a living body. As the bio-derived fiber, it is preferable to use cellulose fiber, chitin fiber or chitosan fiber. Among such fibers, since the environmental load is small and the material cost is low, it is industrially preferable to use cellulose fibers, and it is more preferable to use cellulose microfibrils or derivatives thereof. Cellulose microfibrils are fine fibers formed by bundling dozens of cellulose molecular chains, and cellulose fibers are composed of these cellulose microfibrils further bundled. The diameter of the cellulose fiber is several tens of μm, while the diameter of the cellulose microfibril is several nm to 0.1 μm. Cellulose microfibrils or derivatives thereof have excellent properties such as dispersibility (hydrophilicity), affinity with other substances, and capture / adsorption of fine particles. Further, the chitin fiber or the chitosan fiber is not only excellent in adsorptive ability, but also can be easily hydrophilized by forming a derivative.

The organic fibers are preferably short fibers, and it is more preferable that the short fibers are arranged in the matrix metal in a dispersed state, particularly in a uniformly dispersed state. As a result, the coating material can obtain stable and high strength. The size of the short fibers is preferably 4 to 10 nm in diameter and 5 to 10 μm in length.

Further, in order to effectively increase the strength in a specific direction (particularly the tensile strength), it is preferable that the organic fibers, particularly the short fibers, are dispersed in the matrix metal in a unidirectionally aligned state. On the other hand, when the strength (particularly the tensile strength) is uniformly increased without anisotropy, it is preferable that the organic fibers, particularly the short fibers, are dispersed in the matrix metal in a randomly arranged state.

Organic fibers, especially cellulose fibers, have a softening temperature (220-230 ° C.) lower than the melting point of the metal. Therefore, when organic fibers, particularly cellulose fibers, are heated to a temperature at which the metal melts by a conventionally known pressure casting method or sintering method, the cellulose fibers are thermally decomposed, and cellulose is contained in the matrix metal. It is not possible to produce a film material containing fibers. On the other hand, since cellulose fibers are hydrophilic, when cellulose fibers are added to a plating solution of various metals composed of an aqueous solution (particularly an acidic aqueous solution), the cellulose fibers can be dispersed in the plating solution without agglomeration. be. Next, by performing electroplating (dispersion plating) in a plating solution in which cellulose fibers are dispersed, the cellulose fibers are arranged in a dispersed state in a matrix metal without causing a characteristic change such as thermal decomposition. Can be done. Therefore, the coating material can be formed by an electroplating method.

Further, on an arbitrary surface of the coating material, the average area ratio of the organic fibers in the observation field of view partitioned in the range of ^{100,000 μm 2 is in the range of 2.5% or more and 35% or less, preferably 2.5%.} It is in the range of 25% or less. If the average area ratio of the organic fibers is less than 2.5%, the effect of reducing the coefficient of dynamic friction on the surface of the coating material is small, and excellent sliding characteristics cannot be obtained. On the other hand, if the average area ratio of the organic fibers exceeds 35%, the rate of decrease in conductivity becomes too large due to the increase in the ratio of the organic fibers contained in the matrix metal. By controlling the proportion of organic fibers exposed on the surface of the coating material within a specific range in this way, it is possible to reduce the coefficient of dynamic friction on the surface of the coating material, improve the sliding characteristics, and reduce the conductivity. It can be suppressed as much as possible.

The method for measuring the proportion of organic fibers exposed on the surface of the coating material is not particularly limited, but for example, on an arbitrary surface of the produced coating material, with respect to an observation field segmented within a predetermined range. By performing element mapping by Auger electron spectroscopy and binarizing the obtained element mapping data by a discriminant analysis method, the average area ratio of organic fibers in the observation field can be calculated. At that time, the average area ratio can be calculated from the average value of the area ratios obtained in each observation field of view by arbitrarily selecting a plurality of observation field areas divided in a predetermined range. When a plurality of organic fibers are present in the observation field of view, the average area ratio is calculated by the total area of the fibers of each organic substance in the observation field of view. The average area ratio of the fibers of organic material occupying in the observation visual field range of 100000 ² may be calculated by using a value obtained by converting the range of the observation field of view is defined by a predetermined range 100000 ^2.

On any surface of the coating material, ^{it is preferable that at least one organic fiber is present in the range of 10000 μm 2} or less, and in particular, at least one cellulose fiber is present in the range of ^{1000 μm 2 or less.} preferable. The sliding characteristics can be further improved by having at least one organic fiber in ^{the range of 10,000 μm 2 or less.}

The average mass ratio of the organic fibers contained in the coating material is preferably in the range of 0.02% by mass or more and 10% by mass or less, and the lower limit of the average mass ratio is 0.025% by mass or more. It is more preferable that the upper limit of the average mass ratio is 9% by mass or less. If the average mass ratio is less than 0.02% by mass, the effect of reinforcing the metal by the organic fibers is not sufficient. Therefore, the sliding characteristics of the coating material tend not to be significantly improved as compared with the coating material that does not contain organic fibers. Further, when the film material is formed by an electroplating method, if a certain amount or more of impurities (here, organic fibers) are contained in the plating solution, the composition of the plating solution may be disrupted and metal may not be deposited. In particular, when the average mass ratio exceeds 10% by mass, it tends to be difficult to produce a coating material by the electroplating method. Further, from the viewpoint of suppressing the decrease rate of the conductivity from becoming too large due to the increase in the ratio of the organic fibers contained in the matrix metal, the average mass ratio of the organic fibers is 9% by mass or less. Is preferable.

<Metal>
The metal is an electroplatable metal, for example, nickel (Ni), copper (Cu), palladium (Pd), silver (Ag), tin (Sn), gold (Au), cobalt (Co), zinc ( Zn), iron (Fe), rhodium (Rh), alloys thereof and the like can be mentioned, with nickel, copper, palladium, tin, silver or gold being particularly preferable. Among these, it is more preferable to use copper, silver or tin as the material for electrical contacts, which can realize excellent conductivity and contact resistance / manufacturing cost in a well-balanced manner. In particular, among these metals, copper having both high conductivity and high strength is most suitable. For reference, Tables 1 to 6 show examples of nickel, copper, palladium, silver, tin and gold plating bath compositions and plating conditions.

<Conductivity>
In order to reduce the temperature rise of the material due to Joule heat at the electrical contacts of the coating material, the rate of decrease of the conductivity of the coating material with respect to the conductivity of the metal itself is preferably 35% or less, preferably 30% or less. Is more preferable, and 25% or less is further preferable.

<Manufacturing method of coating material>
The film material is preferably formed by, for example, an electroplating method. When the film material is formed by an electroplating method, the composite material functions as a surface treatment material composed of the film material and a base material having a surface on which the film material is formed. In such a surface treatment material, the coating material is preferably a surface treatment coating laminated on the base material, and more preferably a plating coating formed on the base material by electroplating, for example.

On the other hand, in the above-described embodiment, the case where the coating material is produced by the electroplating method has been described, but any method capable of producing the coating material at a temperature (for example, 200 ° C. or lower) at which the material properties of the organic fibers do not change. However, it is not particularly limited. Other methods for producing the coating material include, for example, an electroless plating method, a sol-gel method, various coating methods, and mixing with a molten metal of a low melting point metal such as low melting point solder.

<Base material>
The base material may be a conductive base material or an insulating base material, depending on the use of the surface treatment material. When the base material is a conductive base material, for example, a metal such as copper, copper alloy, aluminum, aluminum alloy, iron, carbon steel, stainless alloy, or an alloy containing the metal as a main component, as well as carbon and conductive material. Examples thereof include a conductive base material containing a resin or conductive ceramics. On the other hand, when the base material is an insulating base material, it is sufficient as long as a film material can be formed on the surface, and for example, an insulating base material such as glass, ceramics, or elastomer may be used.

<Sliding characteristics>
When the composite material is formed as the surface treatment material, it is preferable that the coefficient of dynamic friction representing the sliding characteristics is low in order to reduce the decrease in the thickness of the surface treatment film due to wear during sliding of the electrical contacts. As the coefficient of dynamic friction of such a composite material, for example, in a reciprocating sliding test in which a steel ball is used as a slider on the surface of a coating material with a load of 100 gf, the number of slides is within the range of 20 to 50 times. The maximum value of the dynamic friction coefficient of is 0.8 or less based on the metal (metal of the coating material) itself, that is, the dynamic friction coefficient ratio is preferably 0.8 or less, and is in the range of 0.3 to 0.65. More preferably.

<Average thickness of coating material>
The average thickness of the coating material is not particularly limited, but if the average thickness of the coating material is too thick, the production cost becomes too high. Therefore, the upper limit of the average thickness is preferably 500 μm or less. Further, when the composite material is formed as a surface treatment material, the sliding characteristics are improved if the surface treatment is slightly performed on the base material. Therefore, from the viewpoint of durability, the lower limit of the average thickness of the coating material is preferably 0.1 μm or more. The average thickness of the coating material can be measured using a scanning electron microscope after the coating material is resin-encapsulated, a cross section is formed in the thickness direction of the coating material, and a cross section is processed by polishing. The measurement is performed at any three points on the cross section, and the average value is calculated as the average thickness.

<Shape of film material>
The shape of the coating material is not particularly limited, and examples thereof include various shapes such as a plate material such as a foil, a thin plate or a thick plate, a wire material, a bar material, a pipe material, and a square material.

<Average particle size of metal crystal grains>
Further, the average particle size of the metal crystal grains in the coating material is smaller in the direction parallel to the surface of the coating material (longitudinal direction) than the average particle size in the thickness direction of the coating material. , The effect of higher strength can be obtained. The average particle size of the metal crystal grains in the direction parallel to the surface of the coating material is preferably 0.2 μm or more and 5.0 μm or less.

<Use of coating materials and composite materials>
By selecting a metal suitable for the application of the coating material of the present embodiment, improvement of sliding characteristics is realized while suppressing deterioration of excellent material properties such as conductivity inherent in the metal itself as much as possible. Therefore, it can be applied to various products in various technical fields.

For example, a surface-treated copper plate (composite material) in which a surface-treated coating (coating material) is formed of copper and organic fibers on a copper plate (conductive substrate) can be used as a terminal for electrical contacts, which is a component of a connector. An electric contact terminal provided with such a composite material can improve the sliding characteristics as an electric contact terminal without lowering the conductivity. Furthermore, it is possible to reduce the size, thickness, and strength of the electrical contact terminal in response to the miniaturization of the connector.

Further, a coating material integrally formed of tin and organic fibers can also be used as a terminal for electrical contacts, which is a component of a connector. The electrical contact terminal provided with such a coating material can improve the sliding characteristics without lowering the conductivity. In addition, it is possible to suppress failures due to sliding of contacts between terminals and improve product life.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, but includes all aspects included in the concept and claims of the present invention, and varies within the scope of the present invention. Can be modified.

Next, the present invention will be described in more detail based on Examples, but the present invention is not limited to these Examples.

(Examples 1 to 7)
On a copper plate (C1100) having a thickness of 0.3 mm, the metal shown in Table 7 and the cellulose fiber as an organic fiber are integrally formed at the average mass ratio shown in Table 7, and a coating material (surface treatment coating) is formed. We confirmed whether it was possible. As the cellulose fiber, a cellulose fiber manufactured by Sugino Machine Limited having a diameter of about 20 nm and a length of several μm was used. About 0.01 to 30% by volume of cellulose fibers are added to the copper plating bath shown in Table 2 with respect to the copper plating bath, and the copper is dispersed in the copper plating bath with stirring, and then the cellulose fibers are dispersed in the copper. Electrocopper plating was performed in the plating bath under the plating conditions shown in Table 2, and a film material was prepared so that the average thickness was 5 μm.

The average thickness of the coating material is measured by encapsulating the coating material with resin, forming a cross section in the thickness direction of the coating material, and processing the cross section by polishing, and then using a scanning electron microscope to measure the thickness of the coating material. Was measured. The measurement was performed at any three points on the cross section, and the average value was calculated as the average thickness.

The average mass ratio of the cellulose fibers contained in the coating material was determined from the ratio of the mass of the residue remaining after dissolving the coating material with nitric acid to the mass of the coating material. The mass of the coating material was calculated by collecting three coating material sample pieces in a section of 45 cm × 15 cm and measuring the mass of each piece. For the mass of the residue, each coating material sample piece collected in a section of 45 cm × 15 cm was immersed in a 20 mass% nitric acid solution to sufficiently dissolve the metal, and then the nitric acid solution containing the residue was adjusted to 2500 rpm. The residue was separated and recovered by centrifugation for 10 minutes, the recovered product was dried, and the mass was measured. The residue after dissolving the coating material with nitric acid was identified as cellulose by Fourier transform infrared spectroscopy. The measurement was performed using a film material sample piece collected from any three places of the film material, and the average value was calculated as an average mass ratio.

The average area ratio of cellulose fibers on the surface of the coating material (surface treatment coating) is as follows. ^{The area ratio per 100,000 μm 2} area of each surface was obtained for any three surfaces by the measurement method described in the average area ratio of, and the average value was calculated as the average area ratio.

(Example 8)
It was produced by the same method as in Examples 1 to 7 except that a coating material using chitosan fiber instead of cellulose fiber in the average mass ratio shown in Table 7 was produced as the organic fiber.

(Comparative Example 1)
The coating material was prepared in the same manner as in Examples 1 to 7 except that the coating material was prepared so that the average area ratio of the cellulose fibers per ^{100,000 μm 2 on} the surface of the coating material (surface-treated coating) was 1.8%. ..

(Comparative Example 2)
The coating material was prepared in the same manner as in Examples 1 to 7 except that the coating material was prepared so that the average area ratio of the cellulose fibers per ^{100,000 μm 2 on} the surface of the coating material (surface-treated coating) was 38.4%. ..

(Conventional example 1)
Electrocopper plating was performed on a copper plate (C1100) having a thickness of 0.3 mm under the copper plating bath and plating conditions shown in Table 2 to form a copper plating film having a thickness of 5 μm to prepare a copper-plated copper plate.

(Example 9)
Whether or not a coating material (surface treatment coating) can be formed by integrally forming the metal shown in Table 7 and the cellulose fiber on a copper plate (C1100) having a thickness of 0.3 mm at the average mass ratio shown in Table 7. Was confirmed. As the cellulose fiber, a cellulose fiber manufactured by Sugino Machine Limited having a diameter of about 20 nm and a length of several μm was used. As the coating material, cellulose fibers were added to the tin plating bath shown in Table 5 in an amount of about 0.01 to 30% by volume with respect to the tin plating bath, stirred and dispersed in the tin plating bath, and then the cellulose fibers. Electrotin plating was performed under the plating conditions shown in Table 5 in a tin-plated bath in which the coating materials were dispersed so that the average thickness of the coating material was 5 μm. The average thickness of the coating material, the average mass ratio of the cellulose fibers contained in the coating material, and the average area ratio of the cellulose fibers on the surface of the coating material were measured by the same methods as in Examples 1 to 7.

(Conventional example 2)
Electric tin plating was performed on a copper plate (C1100) having a thickness of 0.3 mm under the tin plating bath and plating conditions shown in Table 5 to form a tin plating film having a thickness of 5 μm to prepare a tin-plated copper plate.

(Example 10)
Except for the nickel plating conditions shown in Table 1 and the average mass ratio shown in Table 7, the metal and the cellulose fibers were placed on a copper plate (C1100) having a thickness of 0.3 mm in the same manner as in Examples 1 to 7. It was integrally formed and it was confirmed whether or not a coating material (surface treatment coating) could be formed. The average thickness of the coating material, the average mass ratio of the cellulose fibers contained in the coating material, and the average area ratio of the cellulose fibers on the surface of the coating material were measured by the same methods as in Examples 1 to 7.

(Conventional Example 3)
Electronickel plating was performed on a copper plate (C1100) having a thickness of 0.3 mm under the nickel plating bath and plating conditions shown in Table 1 to form a nickel plating film having a thickness of 5 μm to prepare a nickel-plated copper plate.

(Example 11)
Except for the palladium plating conditions shown in Table 3 and the average mass ratio shown in Table 7, the metal and the cellulose fibers were placed on a copper plate (C1100) having a thickness of 0.3 mm in the same manner as in Examples 1 to 7. It was integrally formed and it was confirmed whether or not a coating material (surface treatment coating) could be formed. The average thickness of the coating material, the average mass ratio of the cellulose fibers contained in the coating material, and the average area ratio of the cellulose fibers on the surface of the coating material were measured by the same methods as in Examples 1 to 7.

(Conventional Example 4)
Electropalladium plating was performed on a copper plate (C1100) having a thickness of 0.3 mm under the palladium plating bath and plating conditions shown in Table 3 to form a palladium plating film having a thickness of 5 μm to prepare a palladium-plated copper plate.

(Example 12)
Except for the silver plating conditions shown in Table 4 and the average mass ratio shown in Table 7, the metal and the cellulose fibers were placed on a copper plate (C1100) having a thickness of 0.3 mm in the same manner as in Examples 1 to 7. It was integrally formed and it was confirmed whether or not a coating material (surface treatment coating) could be formed. The average thickness of the coating material, the average mass ratio of the cellulose fibers contained in the coating material, and the average area ratio of the cellulose fibers on the surface of the coating material were measured by the same methods as in Examples 1 to 7.

(Conventional Example 5)
An electric silver plating was performed on a copper plate (C1100) having a thickness of 0.3 mm under the silver plating bath and plating conditions shown in Table 4, and a silver plating film having a thickness of 5 μm was formed to prepare a silver-plated copper plate.

(Example 13)
Except for the gold plating conditions shown in Table 6 and the average mass ratio shown in Table 7, the metal and the cellulose fibers were placed on a copper plate (C1100) having a thickness of 0.3 mm in the same manner as in Examples 1 to 7. It was integrally formed and it was confirmed whether or not a coating material (surface-treated coating) could be formed. The average thickness of the coating material, the average mass ratio of the cellulose fibers contained in the coating material, and the average area ratio of the cellulose fibers on the surface of the coating material were measured by the same methods as in Examples 1 to 7.

(Conventional Example 6)
Electric gold plating was performed on a copper plate (C1100) having a thickness of 0.3 mm under the gold plating bath and plating conditions shown in Table 6 to form a gold plating film having a thickness of 5 μm to prepare a gold-plated copper plate.

For the surface-treated coatings prepared in each Example and Comparative Example and the plating coatings prepared in each Conventional Example, the average area ratio of organic fibers on the surface of the coating material (surface-treated coating), and as characteristics, conductivity and The dynamic friction coefficient was measured by the following method.

Average area ratio of organic fibers on the surface of the coating material (surface treatment coating) A method for measuring the average area ratio of organic fibers will be described with reference to FIG. Note that FIG. 2 is an example when the film material of Example 4 was evaluated, and the same measurement was performed for other Examples and Comparative Examples. First, the film material was cut into a size (3 cm × 3 cm) to be evaluated, immersed in acetone, and ultrasonically cleaned to remove oil on the surface layer of the film material. Then, it was immersed in 10% sulfuric acid for 30 seconds to remove the oxide film on the surface layer. Further, it was washed with ion-exchanged water and then dried to obtain a test piece for evaluation. The evaluation material prepared in this way was washed with water using a scanning Auger electron spectroscope (“PH1680”, manufactured by ULVAC-PHI, Inc.) at a magnification of 300 times, an observation field of view: 400 μm × 280 μm, and 512 scanning lines. The elemental distributions of carbon and oxygen were obtained (evaluated) at three locations on any surface of the treated test piece (see FIG. 2 (a)). The above-mentioned washing treatment with water was performed within 2 hours immediately before the evaluation material was introduced into the Auger electron microscope. This element distribution image is set to 150 for the lower limit threshold and 255 for the upper limit threshold value using image dimension measurement software (“Pixs2000 Pro”, manufactured by Innotek Co., Ltd.), and the separation point is excluded in the binarization setting. On the other hand, the inside was filled to create an image after image processing. (See FIG. 2 (b)).

Further, the obtained image is analyzed, the area ratio is calculated from the ratio occupied by the area of the black-painted portion and the observation range (400 μm × 280 μm: 112000 μm ² ) from the processed image, and the area ratio per ^{100,000 μm 2 (area) is further calculated.} Rate). In addition, after calculating the area of each area of the black-painted part from the processed image and removing the value of the black-painted part ^{set at the edge of the image and the value of the black-painted part which is 1 μm 2 or less.} By calculating the average of the areas of each region, the range in which at least one organic fiber exists (area per location) was calculated. In this way, the same location is calculated for carbon and oxygen, respectively, and in the image after image processing (see FIG. 2B), it is confirmed that the detection locations for carbon and oxygen are almost the same, and organic substances are detected. Of these detection points, the value calculated for carbon, which is less likely to cause an error due to oxidation, was used as the area value of the organic matter. In this way, the area ratio and the area per location are calculated for the element distribution obtained from the three locations on the arbitrary surface, and the average value is calculated for each average area ratio of the coating material and the area per location. The average area was used.

Strictly speaking, in this evaluation method, universal measurement cannot be performed unless the signal intensity and noise level of the element distribution image are always constant and image processing is performed. However, since there are various variable factors such as the state of the sample and the measurement environment, it is practically impossible to keep the signal intensity of the image constant. Therefore, for example, when the average area ratio and the average area per location are calculated by the above observation method, the values calculated for the coating material of Example 4 are the values of this example (values shown in Table 7). ) To ± 20%, it is judged that the appropriate evaluation has been performed, and at the same time, it is judged that the other samples obtained and analyzed have also been appropriately evaluated.

Further, as a method for producing a coating material in which the surface (surface layer portion) of the coating material contains more organic fibers than the average ratio of the entire coating material, for example, as in Examples 1 to 8. In the example, a method of forming the coating material up to 80% of the total thickness and then reducing the current density of electroplating to form the surface layer portion is preferable. In this case, for example, after preparing a coating material having an average thickness of 4 μm under the plating conditions shown in Table 2, the current density is ^{changed to 2 A} / dm 2 to form the remaining 1 μm, whereby more surface layer portions are formed. Organic fibers can be exposed.

Measurement of conductivity After forming a surface treatment film (plating film) with a thickness of 10 μm on the cathode electrode (titanium plate), the surface treatment film (plating film) is peeled off from the titanium plate, and the surface treatment film (plating film) is peeled off. Three test materials were prepared for each of the above. The specific resistance values of each of the three test materials produced were measured by the four-terminal method in a constant temperature bath maintained at 20 ° C. (± 0.5 ° C.). The conductivity was calculated from the measured resistivity values, and their average values were calculated. The distance between the terminals was set to 200 mm.

Measurement of Dynamic Friction Coefficient Three composite materials (surface-treated materials) on which the coating materials (surface-treated coatings) shown in Table 7 were formed on a copper plate (C1100) having a thickness of 0.3 mm were prepared. The dynamic friction coefficient was measured on each of the three produced composite materials (test materials) using a sliding test device (HEIDON Type: 14FW, manufactured by Shinto Kagaku Co., Ltd.). The measurement conditions are R = 3.0 mm steel ball probe, sliding distance: 10 mm, sliding speed: 100 mm / min, number of slides: 50 round trips, load 100 gf. The dynamic friction coefficient was evaluated by the ratio (dynamic friction coefficient ratio) of the maximum value of the dynamic friction coefficient in the range of 20 to 50 sliding times to the original metal film (plating film of the conventional example) containing no organic fiber.

From the results in Table 7, when the metal is copper-plated (Examples 1 to 8, Conventional Examples 1 and Comparative Examples 1 and 2), the dynamic friction coefficient of Comparative Example 1 in which the average area ratio is less than 2.5%. Was not found to be superior to Conventional Example 1. On the other hand, in Examples 1 to 6 in which the average area ratio is in the range of 2.5% or more and 35% or less, the dynamic friction coefficient ratio is remarkably smaller than the reduction rate of the conductivity. Among them, Examples 1 to 5 in which the average area ratio is in the range of 2.5% or more and 25% or less and the average area per location ^{is in the range of 1000 μm 2} or less have a dynamic friction coefficient ratio of 0.65. It was smaller, and the rate of decrease in conductivity was 25% or less, which was particularly excellent.

Example 7 having an average area ratio of 30.4% had a slightly larger decrease in conductivity than Examples 1 to 5 having an average area ratio of 2.5% or more and 25% or less, but dynamic friction. The coefficient ratio was extremely small.

In Example 8 in which the organic fiber contained in the film material (surface-treated film) was chitosan fiber, the coefficient of dynamic friction ratio was significantly smaller than the rate of decrease in conductivity.

On the other hand, in Comparative Example 2 in which the average area ratio was 38.4% and the average area per location was ^{larger than 10000 μm 2} , the rate of decrease in conductivity was significantly larger than that in the dynamic friction coefficient ratio.

Comparing Example 9 in which the metal is tin-plated with Conventional Example 2, the coefficient of dynamic friction ratio was significantly smaller in Example 9 than in the rate of decrease in conductivity.

Comparing Example 10 in which the metal is nickel-plated with Conventional Example 3, the coefficient of dynamic friction ratio was significantly smaller in Example 10 than in the rate of decrease in conductivity.

Comparing Example 11 in which the metal is palladium-plated with Conventional Example 4, the coefficient of dynamic friction ratio was significantly smaller in Example 11 than in the rate of decrease in conductivity.

Comparing Example 12 in which the metal is silver-plated with Conventional Example 5, the coefficient of dynamic friction ratio was significantly smaller in Example 12 than in the rate of decrease in conductivity.

Comparing Example 13 in which the metal is gold-plated with Conventional Example 6, the dynamic friction coefficient ratio was significantly smaller in Example 15 than in the rate of decrease in conductivity.

(Examples 14 to 16)
Copper and cellulose fibers are integrally formed on a copper plate (C1100) having a thickness of 0.3 mm in the same manner as in Examples 1 to 7 except for the average area ratio shown in Table 8, and the average thickness is different. A surface treatment film (coating material) was formed. The average thickness of the coating material, the average mass ratio of the cellulose fibers contained in the coating material, and the average area ratio of the cellulose fibers on the surface of the coating material were measured by the same methods as in Examples 1 to 7.

(Conventional Example 7)
Electrocopper plating was performed on a copper plate (C1100) having a thickness of 0.3 mm under the copper plating bath and plating conditions shown in Table 2 to form a copper plating film having a thickness of 30 μm to prepare a copper-plated copper plate.

In Examples 14 to 16 and Conventional Example 7, the average area ratio, the average area per location, the conductivity, and the dynamic friction coefficient were measured in the same manner as in Examples 1 to 7.

From the results in Table 8, even when the average thickness of the coating material was in the range of 0.1 μm or more and 500 μm or less, the conductivity and the dynamic friction coefficient ratio were excellent as in Examples 1 to 7.

According to the present invention, it is provided a coating material having improved sliding characteristics and a method for producing the same, and a composite material having the same and terminals for electrical contacts, while suppressing a decrease in conductivity inherent in the metal itself as much as possible. Is now possible.

1 Composite material 2 Organic fiber 3 Coating material 4 Base material 5 Metal (matrix metal)

Claims (14)

Electroplatable metal and
Organic fibers having carbon and oxygen arranged in a dispersed state in the metal,
It is a film material with
The coating material is characterized in that, on an arbitrary surface of the coating material, the average area ratio of the fibers of the organic substance in the observation field of view partitioned in the range of ^{100,000 μm 2 is in the range of 2.5% or more and 35% or less.} .. The coating material according to claim 1, wherein at least one of the organic fibers is present on an arbitrary surface of the coating material ^{within a range of 10,000 μm 2 or less.} The coating material according to claim 1 or 2, wherein the average area ratio is 2.5% or more and 25% or less. The coating material according to any one of claims 1 to 3, wherein the average mass ratio of the organic fibers contained in the coating material is 0.02% by mass or more and 10% by mass or less. The coating material according to any one of claims 1 to 4, wherein the coating material has an average thickness of 500 μm or less. The coating material according to any one of claims 1 to 5, wherein the metal is Cu, Ag, Au, Sn, Ni or Pd. The coating material according to any one of claims 1 to 6, wherein the pre-organic substance is a cellulose fiber. The metal is Cu, Ag or Sn.
The average area ratio is 2.5% or more and 25% or less.
The coating material according to any one of claims 1 to 7, wherein the organic fiber is a cellulose fiber and at least one is present within a range of ^{1000 μm 2 or less on an arbitrary surface of the coating material.} .. In a reciprocating sliding test in which a steel ball is used as a slider on the surface of the coating material with a load of 100 gf, the maximum value of the dynamic friction coefficient under the condition that the number of slides is within the range of 20 to 50 is based on the metal itself. The coating material according to any one of claims 1 to 8, which is 0.8 or less. A composite material comprising a base material and the coating material according to any one of claims 1 to 9 formed on the surface of the base material. The composite material according to claim 10, wherein the base material is a conductive base material. The composite material according to claim 10, wherein the base material is an insulating base material. An electrical contact terminal provided with the coating material according to any one of claims 1 to 9. The method for producing a coating material according to any one of claims 1 to 9, which is formed by an electroplating method.

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