JP4430570B2 - Electroless nickel composite plating bath and electroless nickel alloy composite plating bath - Google Patents

Description

  The present invention relates to an electroless nickel or nickel alloy composite plating bath (hereinafter sometimes referred to as “electroless nickel (alloy) composite plating bath”) and an electroless nickel or nickel alloy composite plating method (hereinafter referred to as “electroless nickel ( Alloy) may be described as “composite plating method”. More specifically, an electroless nickel (alloy) composite plating bath capable of composite co-deposition of fine particles such as fluororesin in a nickel (alloy) plating film by electroless nickel (alloy) plating, which is chemical plating, and The present invention relates to an electroless nickel (alloy) composite plating method.

  Conventionally, composite plating baths in which fine particles such as fluororesin, nylon, polyethylene, graphite, graphite fluoride, molybdenum disulfide, and boron nitride are dispersed in an electroless metal plating bath are known. Then, by immersing the object to be plated in this composite plating bath and performing electroless composite plating, a metal film is chemically deposited on the surface of the object to be plated, and fine particles and short fibers are coexisted in the metal film. A means for obtaining a composite plating film in which the fine particles are dispersed in a metal matrix is known. For example, by using a composite plating bath in which polytetrafluoroethylene (PTFE) fine particles are dispersed in an electroless nickel-phosphorus (Ni-P) plating solution, PTFE fine particles co-deposited in the Ni-P plating film. A Ni-P / PTFE composite plating film is obtained. This Ni-P / PTFE composite plating film is a plating film having both low physical properties and non-adhesive properties of PTFE along with various physical properties of nickel metal.

  The electroless nickel (alloy) plating solution used as the above metal matrix contains water-soluble salts of elements with extremely large environmental impact such as mercury, arsenic, cadmium, and lead as stabilizers to maintain the stability of the plating bath. Or ions have been added. The presence of these stabilizers suppresses the random reduction of nickel ions at the temperature required for the reduction reaction of nickel ions to metal, that is, a reaction generally referred to as self-decomposition, and the nickel (alloy) plating film Good production and good continuous use of the plating bath were possible.

  However, since these stabilizers are also present as ions in the electroless nickel (alloy) plating bath, when a nickel (alloy) plating film is generated by a reduction reaction from the electroless nickel (alloy) composite plating bath, It has been known for a long time that these stabilizer ions are simultaneously reduced to a metal and taken into the nickel (alloy) film or eutectoid in the nickel (alloy) film.

  By the way, it has been pointed out that elements such as mercury, arsenic, cadmium, lead, etc. present in the plating film may affect the environment and the human body. Regulations such as restriction directive (RoHS), used automobile directive (ELV), and law regarding the procurement of environmental goods in Japan (Green Purchasing Law) in Japan have been established. The use of hazardous substances is prohibited. Among these harmful substances, stabilizer elements such as mercury, arsenic, cadmium, and lead, which have been conventionally used as stabilizers in electroless plating baths, are also included.

  Among these stabilizer elements, mercury, arsenic, and cadmium have been used less early because they are particularly harmful and environmental impacts, but lead is used as a stabilizer for electroless nickel plating baths. It has become common to use. However, lead is a substance that has been confirmed to affect the human body and the environment, and a stabilizer element in place of lead has been desired.

  To date, tellurium, thallium and the like have been published as alternative stabilizer elements (Non-Patent Document 1 and Non-Patent Document 2). However, it was not as good as lead.

  In addition, metal salts such as iron, copper, tin, cobalt, tungsten, rhenium, manganese, palladium, vanadium, zinc, chromium, gold, silver, and platinum are added to these electroless nickel plating baths, and electroless nickel alloy composites are added. It is known as a plating bath. However, these metals are intended to be alloyed with nickel, and improve physical properties such as hardness and wear resistance of the electroless nickel film, and have little effect as stabilizers.

  The above problem is not only a problem of simple electroless nickel (alloy) plating, but also in electroless nickel (alloy) composite plating in which water-insoluble materials such as fine particles and short fibers are added to this and eutectoid. It was to be solved.

Ibaraki Prefectural Industrial Technology Center Research Report No. 21, P.76-77 (1993) Abstracts of the 88th Annual Conference of the Surface Technology Society of Japan P. 185-186 (1993)

  The present invention has been made in view of such a technical background, and the problem is that a good plating film can be obtained without substantially containing harmful substances such as lead, and a water-insoluble material in the plating film can be obtained. It is an object to provide an electroless nickel (alloy) composite plating bath that is excellent in eutectoid deposition and can achieve continuous use of the plating bath.

  As a result of intensive studies to solve the above problems, the present inventors have found that such problems can be solved by adding a specific element to an electroless nickel (alloy) composite plating bath, and the present invention has been completed. did.

  That is, the present invention provides an electroless nickel (alloy) composite plating bath containing a water-soluble nickel salt, a reducing agent, molybdenum and antimony, and a water-insoluble material.

  The present invention also provides an electroless nickel (alloy) composite plating bath containing a water-soluble nickel salt, an alloyed metal salt, a reducing agent, molybdenum and antimony, and a water-insoluble material.

  According to the present invention, an electroless nickel (alloy having excellent plating film appearance, plating deposition rate, eutectoid property of water-insoluble material and plating bath stability can be obtained without substantially containing harmful substances such as lead. ) A plating bath can be provided. In addition, the electroless nickel (alloy) plating bath is less likely to deteriorate the performance even during continuous use of the plating bath, so that the plating bath needs to be renewed and the working efficiency can be improved. .

  The present invention relates to an electroless nickel composite plating bath containing at least a water-soluble nickel salt, a reducing agent, molybdenum and antimony, and a water-insoluble material, and an electroless nickel alloy obtained by further adding an alloying metal salt to the electroless nickel composite plating bath It is a composite plating bath.

  The water-soluble nickel salt in the electroless nickel (alloy) composite plating bath of the present invention is not particularly limited, and commonly used water-soluble nickel salts such as nickel sulfate, nickel chloride, nickel acetate, nickel nitrate, and hypophosphorous acid. It is blended in the plating bath as nickel oxide or the like. These can be used individually by 1 type or in combination of 2 or more types.

  The blending amount of these water-soluble nickel salts in the electroless nickel (alloy) composite plating bath is not particularly limited, but the nickel ion concentration is preferably 0.1 g / L to 100 g / L. It is particularly preferably 1 g / L to 50 g / L. If it is less than 0.1 g / L, it may be unreacted, and if it is more than 100 g / L, decomposition due to overreaction may occur.

  Further, the reducing agent that can be used in the electroless nickel (alloy) composite plating bath of the present invention is not particularly limited. Preferred examples include hypophosphorous acid, sodium hypophosphite, hypophosphorous acid. Hypophosphorous acid (salt) such as potassium; amine borane such as dimethylamine borane and trimethylamine borane; hydrazine (salt) such as hydrazine; sodium borohydride and the like. These can be used individually by 1 type or in combination of 2 or more types.

  The concentration of this reducing agent in the electroless nickel (alloy) composite plating bath varies depending on the type of reducing agent used and the required deposition rate, but 1 g / L to 100 g / L for the entire plating bath. Is preferable, and 2 g / L to 50 g / L is particularly preferable. If it is less than 1 g / L, it may be unreacted, and if it is more than 100 g / L, decomposition due to overreaction may occur.

  A feature of the electroless nickel (alloy) composite plating of the present invention is that it contains both molybdenum and antimony in its composition.

  Although there is no particular limitation on the form of molybdenum in the electroless nickel (alloy) composite plating bath, it is preferable to take the form of molybdate ions or molybdenum ions. For example, molybdate such as sodium molybdate, potassium molybdate, and ammonium molybdate; molybdate hydrates; molybdic acid, etc. should be added to the electroless nickel (alloy) composite plating bath. These can be used singly or in combination of two or more.

  The content of the molybdenum with respect to the entire plating bath is not particularly limited, but is preferably 0.1 mg / L to 1 g / L in terms of molybdenum metal, and particularly preferably 10 mg / L to 500 mg / L. preferable. Moreover, it is still more preferable that it is 20 mg / L-200 mg / L. If it is less than 0.1 mg / L, it may self-decompose, and if it is more than 1 g / L, the plating appearance may be poor or the reaction may be stopped.

  On the other hand, the form of antimony in the plating bath is not particularly limited, but it is preferably in the form of antimonate ions or antimony ions. This antimony includes, for example, antimonic acid salts such as sodium antimonate, potassium antimonate, and ammonium antimonate; their antimonate hydrates; antimonic acid; antimonyl-L-tartaric acid, and antimonyl potassium tartrate. (Alloy) It can be added to the composite plating bath, and these can be used alone or in combination of two or more.

  The content of antimony with respect to the entire plating bath is not particularly limited, but in terms of antimony metal, it is preferably 0.1 mg / L to 1 g / L, and preferably 0.5 mg / L to 200 mg / L. Particularly preferred. Further, it is more preferably 1 mg / L to 100 mg / L. If it is less than 0.1 mg / L, it may self-decompose, and if it is more than 1 g / L, the plating appearance may be poor or the reaction may be stopped.

  Further, the mixing ratio of molybdenum and antimony is not particularly limited, but 0.5 to 20 parts by weight of antimony is preferable with respect to 100 parts by weight of molybdenum. Particularly preferred is 1 to 10 parts by weight. If it is less than 0.5 part by weight, it may decompose by itself, and if it is more than 20 part by weight, the plating appearance may be poor or the reaction may be stopped. Further, the content of the total of molybdenum and antimony with respect to the entire plating bath is not particularly limited, but is preferably 25 mg / L to 1 g / L, and particularly preferably 50 mg / L to 200 mg / L.

  When the electroless nickel (alloy) composite plating bath of the present invention is an electroless nickel alloy composite plating bath, it is necessary to further contain an alloying metal salt. This alloyed metal salt is added to improve physical properties such as hardness, magnetism, spreadability, electrical resistance, and toughness of the plating film, and is not particularly limited. Examples thereof include iron, copper, tin, cobalt, tungsten, rhenium, manganese, palladium, vanadium, zinc, chromium, gold, silver, platinum, and the like. These alloyed metal salts can be used singly or in combination of two or more.

  The content of the alloyed metal salt with respect to the entire electroless nickel alloy composite plating bath is preferably 0.1 g / L to 100 g / L as a water-soluble alloyed metal salt, and preferably 1 g / L to 50 g / L. It is particularly preferred.

  On the other hand, the water-insoluble material contained in the electroless nickel (alloy) composite plating bath of the present invention for the purpose of improving the film properties is not particularly limited, and water-insoluble fine particles generally used in electroless composite plating baths. Or short fibers can be used singly or in combination of two or more. Examples of these water-insoluble materials include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), fluororesins such as fluorinated pitch or fluorinated compounds; organics such as nylon and polyethylene Polymers: Inorganic materials such as graphite, fluorinated graphite, molybdenum disulfide, boron nitride, silicon carbide, titanium oxide, diamond; carbon nanotubes, and the like.

  Among the above water-insoluble materials, examples of PTFE include Lubricant L-170J and L-172J (both manufactured by Asahi Glass Co., Ltd.), Lubron L-2 and L-5 (both manufactured by Daikin Industries, Ltd.), and Zonyl MP. -1100, MP-1200, TLP10F-1 (both manufactured by DuPont) and the like can be mentioned, and these can be used.

  These water-insoluble materials are preferably in the form of fine particles, and have a particle size such that they are appropriately dispersed in an electroless nickel (alloy) composite plating bath and can be co-deposited in the metal matrix in the plating film. There is no particular limitation as long as it is a material, but generally a material having a size of 100 μm or less, preferably 0.1 to 10 μm may be used. Furthermore, it may be in the form of a short fiber having a length of 100 μm or less, preferably 5 to 100 μm.

  The content of the water-insoluble material is not particularly limited as long as it does not impair the precipitation of the electroless nickel (alloy) plating, but is 0 to 500 g / L with respect to the entire electroless nickel (alloy) composite plating bath. 1 g / L to 10 g / L is particularly preferable. When the amount is more than 500 g / L, good deposition of the plating film cannot be obtained, and uniform dispersion of the water-insoluble material in the film may not be obtained.

  A dispersion aid can be added to the electroless nickel composite plating bath of the present invention for good dispersion of the water-insoluble material and the effect of promoting eutectoid. Such a dispersion aid is not particularly limited as long as it is generally used for composite plating, but a surfactant may be used when the water-insoluble material used has water repellency and hydrophobicity. desirable.

  Examples of such surfactants are not particularly limited as long as a good dispersion effect and eutectoid promoting effect can be obtained in use. Cationic surfactants and amphoteric interfaces exhibiting cationic properties in the pH range to be used are used. An activator or a nonionic surfactant may be mentioned.

  As the above-mentioned surfactant, generally known fluorine-based surfactants and hydrocarbon-based surfactants can be used singly or in combination of two or more. Among these, perfluoroalkyl quaternary ammonium salts such as Megafac F150 (Dainippon Ink Chemical Co., Ltd.), Florard FC-135 (Sumitomo 3M Limited), Surflon S- 121 (manufactured by Seimi Chemical Co., Ltd.) As hydrocarbon-based surfactants, high amine (Lonza Japan Co., Ltd.) which is benzethonium chloride, Nissan Anon BF (manufactured by Nippon Oil & Fats Co., Ltd.) which is alkylbetaine. ) Nissan Anon BDC-SF (manufactured by NOF Corporation), which is fatty acid amidopropyldimethylacetate betaine.

  Of these, fluorinated surfactants have been pointed out in recent years as being environmentally hazardous substances because they are difficult to decompose, and further, their accumulation in the human body has also been pointed out, so their production and use are being prohibited. For example, it is desirable to use a hydrocarbon-based surfactant disclosed in JP 2004-60050 A.

  The hydrocarbon-based surfactant disclosed in the above Japanese Patent Application Laid-Open No. 2004-60050 is represented by the following formula (1), and has a fatty acid amide alkyl group in the structure. It is an amphoteric surfactant characterized by substantially exhibiting a cationic property under the conditions of acidity from acidic to weakly acidic.

（式中、Ｒ¹は炭素数７〜２０のアルキル基、Ｒ²は炭素数１〜６のアルキル基、炭素数１
〜６のヒドロキシアルキル基または炭素数１〜６のアルコキシル基、Ｒ³は炭素数１〜６のアルキル基、炭素数１〜６のヒドロキシアルキル基または炭素数１〜６のアルコキシル基、ｎは１〜６の整数を示す）

(In the formula, R ¹ is an alkyl group having 7 to 20 carbon atoms, R ² is an alkyl group having 1 to 6 carbon atoms, and 1 carbon atom.
6 hydroxyalkyl group or an alkoxyl group having 1 to 6 carbon atoms, R ³ is an alkyl group having 1 to 6 carbon atoms, a hydroxyalkyl group or an alkoxyl group having 1 to 6 carbon atoms having 1 to 6 carbon atoms, n represents 1 Represents an integer of ~ 6)

Examples of the fatty acid moiety (R ¹ CO—) of the compound (1) include those derived from coconut oil fatty acid, palm kernel oil fatty acid, lauric acid, myristic acid, palmitic acid, stearic acid and the like. In the electroless composite plating bath of the present invention, the fatty acid portion is derived from a coconut oil fatty acid or a palm kernel oil fatty acid containing a myristylic acid or palmitic acid having a longer alkyl chain than lauric acid. It is preferable in terms of stability in the interior and thermal stability when using a plating bath.

Examples of the alkyl group having 1 to 6 carbon atoms in the groups R ² and R ³ of the compound (1) include methyl, ethyl, propyl, butyl, pentyl, hexyl and the like, and hydroxyalkyl having 1 to 6 carbon atoms. Examples of groups include hydroxymethyl, hydroxyethyl, hydroxypropyl, hydroxybutyl, hydroxypentyl, hydroxyhexyl, etc. Examples of alkoxyl groups having 1 to 6 carbon atoms include methoxyl, ethoxyl, propoxyl, butoxyl, pentyl. Examples thereof include oxyl and hexyloxyl. Among these, a lower alkyl group, particularly a methyl group is preferable because the compound can be easily obtained.

  Examples of the compound (1) include, for example, Nissan Anon BDC-SF, Nissan Anon BDF-SF (all manufactured by NOF Corporation), Adeka Anhhot PB-30L (manufactured by Asahi Denka Kogyo Co., Ltd.), Enagicol The fatty acid amide propyl dimethyl acetate betaine marketed as C-30B, Enadicol L-30B (all are the Lion Co., Ltd.) etc. can be mentioned, These can be obtained easily.

  In the electroless composite plating bath of the present invention, when the compound (1) is used as a surfactant, the concentration thereof is preferably 1000 mg / L or less, preferably 20 to 600 mg / L, in the composition of the plating bath. It is more preferable.

  Furthermore, in the electroless nickel (alloy) composite plating bath of the present invention, various inorganic acids and organic acids are preferably used as complexing agents. Specific examples thereof include boron compounds such as boric acid and borax; Monocarboxylic acid compounds such as acetic acid, propionic acid, malic acid, lactic acid, succinic acid, malonic acid, adipic acid, citric acid, gluconic acid and glycolic acid, dicarboxylic acid compounds or hydroxycarboxylic acid compounds; amino acids such as glycine, etc. Can be mentioned. These can be used individually by 1 type or in combination of 2 or more types.

  The content of the complexing agent is not particularly limited as long as the effect of the present invention is not impaired, but is preferably 1 g / L to 100 g / L with respect to the entire electroless nickel (alloy) composite plating bath, 10 g / L to 40 g / L is particularly preferable. If it is less than 1 g / L, it may self-decompose or nickel phosphite may be produced when hypophosphite is used as a reducing agent. Moreover, when more than 100 g / L, unreacted and sufficient reaction rate may not be obtained.

  Furthermore, the electroless nickel (alloy) composite plating bath of the present invention can contain a reaction accelerator. The reaction accelerator is not particularly limited, but an organic sulfur compound or an inorganic sulfur compound is preferably used. Specifically, thiosulfate, thionate, polythionate, thiourea, thiocyanate, thiosulfonate, thiocarbonate, thiocarbamate, thiosemicarbazide, sulfide, disulfide, thiol, mercaptan, etc. These can be used singly or in combination of two or more.

  The content of the reaction accelerator is not particularly limited as long as the effect of the present invention is not impaired, but is 0.001 mg / L to 1000 mg / L with respect to the entire electroless nickel (alloy) composite plating bath. Preferably, 0.01 mg / L to 100 mg / L is particularly preferable. If it is less than 0.001 mg / L, the reaction promoting effect may not be obtained, and if it is more than 1000 mg / L, the plating appearance may be poor or the reaction may be stopped.

  Although the electroless nickel (alloy) composite plating bath of the present invention does not substantially contain mercury, arsenic, cadmium or lead, the present invention has little possibility of affecting the environment and the human body, and regulations and guidelines It does not exclude the inclusion of such a trace amount of metal that is not subject to such as.

  The method of using the electroless nickel (alloy) composite plating bath of the present invention obtained as described above may be the same as the method of using a normal electroless composite plating bath, and is not particularly limited. Can be used under the following conditions.

  That is, the electroless nickel (alloy) composite plating bath of the present invention may be constructed, and an object to be plated that has been degreased, washed with water, activated, etc., may be immersed therein. The pH of the electroless nickel (alloy) composite plating bath is not particularly limited, but is preferably 3 to 10 and more preferably 4 to 9 during plating. By setting the pH of the electroless plating bath to this range, an efficient reduction reaction of metal ions proceeds, and the effect of improving the deposition rate of the electroless plating film can be obtained. For adjusting the pH of the plating bath, an acid such as hydrochloric acid, sulfuric acid or sulfamic acid, or an alkali such as sodium hydroxide or ammonium hydroxide, preferably diluted with water, can be added as appropriate.

  Further, the temperature of the bath during plating of the electroless nickel (alloy) composite plating bath of the present invention is not particularly limited as long as it is a temperature at which nickel ion reduction reaction is performed, but an efficient reduction reaction is caused. Therefore, 15-98 degreeC is preferable and 25-90 degreeC is especially preferable.

  Furthermore, in performing electroless nickel (alloy) composite plating using the electroless nickel (alloy) composite plating bath of the present invention, as a result of the reduction of metal ions to metal by a reducing agent as the plating proceeds, the plating solution The metal ion concentration and the reducing agent concentration in the medium are lowered, and the pH is also lowered. Therefore, water-soluble nickel salt, reducing agent, complexing agent, molybdenum, antimony, pH adjusting agent, etc. are replenished continuously or at appropriate times in an electroless nickel (alloy) composite plating bath. It is preferable to return the concentration to the original concentration. It is also preferable to measure the metal ion concentration, the reducing agent concentration and the pH in the plating solution continuously or at appropriate time intervals, and replenish them according to the measurement results.

  EXAMPLES Next, although an Example is given and this invention is demonstrated further, this invention is not restrict | limited at all by these Examples.

Example 1
Evaluation of initial performance of electroless nickel composite plating bath:
The electroless nickel composite plating bath of the present invention having the following composition and containing molybdenum and antimony as stabilizers was prepared according to a conventional method. A plating test was conducted using the obtained plating solution. For comparison, a material containing only one of molybdenum and antimony and a material containing lead were used. The results are shown in Table 1. In Table 1, the contents of molybdenum, antimony and lead are the contents as metals.

<Electroless nickel composite plating bath composition>
Nickel sulfate hexahydrate 25g / L
Sodium hypophosphite monohydrate 20g / L
DL-malic acid 25g / L
Milk acid 10g / L
Acetic acid 5g / L
Surfactant (fatty acid amide propyldimethylacetate betaine) 50mg / L
PTFE (MP-1100) 4g / L
Stabilizer Amounts listed in Table 1

<Plating test>
An SPCC-SB iron plate (size: 0.3 mm x 50 mm x 50 mm) was used as a specimen to be plated, and immersed in 1 L of each of the above electroless nickel composite plating baths under the following plating conditions. Composite plating was performed.

Plating conditions:
PH of plating solution 4.9
Bath temperature 90 ° C
Stirring Mild mechanical stirring Plating time 20 minutes

  About the obtained electroless nickel composite plating film | membrane, the plating film external appearance was evaluated on the following judgment conditions. Further, the deposition rate was measured to evaluate the plating bath stability. The results are also shown in Table 1.

Evaluation of deposition rate:
The deposition rate per hour was determined according to the following criteria.
Judgment Precipitation rate
: 10 μm / hr or more
○: 5 μm / hr or more and less than 10 μm / hr
Δ: Less than 5 μm / hr
×: No reaction

Evaluation of plating bath stability:
The deposit on the bottom of the plating tank during plating was visually confirmed and judged according to the following criteria.
Judgment Visual confirmation of precipitate
◎: No dotted precipitate with a diameter of 1 mm or less
○: 1 to 5 or less dotted precipitates having a diameter of 1 mm or less could be confirmed.
Δ: No more than 6 to 20 dot precipitates having a diameter of 1 mm or less could be confirmed.
X: 21 or more dotted precipitates having a diameter of 1 mm or less were confirmed.

Evaluation of PTFE eutectoid amount:
The capacity of PTFE contained in the plating film was examined and judged according to the following criteria.
Judgment Amount in coating
: 25% or more by volume
○: 20% by volume or more and less than 25% by volume
Δ: 15% by volume or more and less than 20% by volume
×: Less than 15% by volume

Evaluation of plating film appearance:
The appearance of the plating was visually observed and judged according to the following criteria.
Judgment Plating film appearance
◎: Dark gray and uniform
○: Dark gray and slightly uniform
△: Dark gray and uneven
×: Dark gray, partially or partially nickel-colored and non-uniform

  From this result, it was confirmed that the same effect as the plating solution (Comparative Product 1) containing lead was obtained only when the plating containing the molybdenum and antimony (Products 1 to 3 of the present invention) was used.

Example 2
Continuous use test of electroless nickel composite plating bath:
The continuous use test was performed on the electroless nickel composite plating bath of the present invention product 1 in Table 1 and the comparative product 1. In the continuous use test, each electroless nickel composite plating bath immediately after the building bath and after using 0.5, 1.0, 1.5, and 2.0 turns continuously, the deposition state of the plating film, the amount of PTFE eutectoid, The relative deposition rate and plating stability were investigated. The deposition state and relative deposition rate of the plating film were evaluated using the following judgment conditions. The amount of PTFE eutectoid and the stability of plating were evaluated by the same method as in Example 1. The results are shown in Table 2.

  In addition, 1 turn means the time until an amount of nickel metal corresponding to the initial nickel ion concentration in the electroless nickel composite plating bath is theoretically plated. For example, when the initial nickel ion concentration in the electroless nickel composite plating bath is M [g / L], the time when nickel of M [g / L] is deposited by plating is defined as 1 turn, and 5 turns. Means the time required for 5 × M [g / L] nickel plating.

Deposition state of plating film:
The appearance of the plating film was visually observed and judged according to the following criteria.
Judgment Deposition state of plating film
A: Glossy satin finish with good uniform appearance
○: Uniform appearance with a satin finish with slightly reduced gloss
△: Matte appearance with no gloss
X: Appearance with rough precipitation

Relative deposition rate:
The precipitation rate at the time of continuous use for each turn was measured by the same method as in Example 1, and the rate of decrease of the measured value with respect to the initial deposition rate was evaluated according to the following criteria.
Judgment Precipitation rate
◎: 0% to 10% lower
○: Decreased by 10% to 20%
Δ: Reduced by 20% to 50%
×: Reduced by 50% or more

  As is clear from this result, it was confirmed that the electroless nickel composite plating bath of the present invention has a performance comparable to that of an electroless nickel composite plating bath using lead even when used for a long time.

Example 3
Electroless nickel-copper-phosphorus alloy composite plating bath:
<Composition>
Nickel sulfate hexahydrate 15g / L
Copper sulfate pentahydrate 0.75g / L
Sodium hypophosphite monohydrate 30g / L
Citric acid 60g / L
Ammonium chloride 45g / L
Surfactant (fatty acid amidopropyl 50mg / L
Dimethyl ether acetate)
PTFE (MP-1100) 4g / L
Stabilizer Mo 100mg / L
Sb 10mg / L

<Plating conditions>
pH 5.8
Bath temperature 80 ° C

  An electroless nickel-copper-phosphorus alloy is known to have excellent corrosion resistance and provide stable contact resistance. By co-depositing the PTFE fine particles with this, a functional plating film having both low friction and non-adhesive properties which are characteristics of PTFE can be obtained. Therefore, this plating has better corrosion resistance and wear resistance than electroplating of precious metals such as gold, so that it can be used as electrical contacts for connectors and reed switches that currently use precious metals. It is.

Example 4
Electroless nickel-tungsten-phosphorus alloy plating bath:
<Composition>
Nickel sulfate hexahydrate 20g / L
Sodium tungstate dihydrate 20g / L
Sodium hypophosphite monohydrate 20g / L
Sodium citrate 35g / L
Lactic acid 5g / L
Ammonium sulfate 30g / L
Surfactant (fatty acid amidopropyl 50mg / L
Dimethyl acetate betaine)
PTFE (MP-1100) 4g / L
Stabilizer Mo 100mg / L
Sb 10mg / L

<Plating conditions>
pH 5.0
Bath temperature 80 ° C

  Electroless nickel-phosphorus plating with a phosphorus content of 5% or less is called low phosphorus electroless nickel and has advantages such as wear resistance, high resistivity, and high hardness. It is known that when tungsten is co-deposited with the electroless nickel-phosphorous plating, the thermal stability and corrosion resistance of the electroless nickel-phosphorous plating are remarkably improved. Since the plating solution of this example is obtained by co-depositing PTFE fine particles, it has both the characteristics of the electroless nickel-tungsten-phosphorus alloy and the low-friction and non-adhesive properties of PTFE. It becomes a functional plating film.

  According to the present invention, it is possible to provide an electroless nickel (alloy) composite plating bath that is excellent in plating film appearance, deposition rate, and plating bath stability, without substantially containing harmful substances such as lead. it can. The electroless nickel (alloy) composite plating bath is less likely to deteriorate the excellent performance even during continuous use, so that the plating bath needs to be renewed and work efficiency can be improved.

Therefore, the electroless nickel (alloy) composite plating bath of the present invention can be suitably used in a wide range of applications as a composite plating containing a water-insoluble material such as fine particles.

more than

Claims (18)

(1) water-soluble nickel salt,
(2) reducing agent,
(3) Selected from the group consisting of molybdic acid, molybdate and molybdate hydrate
One or more kinds of molybdenum,
(4) Antimonic acid, antimonate, antimonate hydrate, antimonyl-L-
One selected from the group consisting of tartaric acid and potassium antimonyl tartrate, or
Two or more antimony and
(5) An electroless nickel composite plating bath containing a water-insoluble material.   The electroless nickel composite plating bath according to claim 1, further comprising a complexing agent.   The electroless nickel composite plating bath according to claim 1 or 2, further comprising a reaction accelerator. The electroless nickel composite plating bath according to any one of claims 1 to 3, which contains (3) molybdenum in a range of 0.1 mg / L to 1 g / L. The electroless nickel composite plating bath according to any one of claims 1 to 4, wherein the antimony of (4) is contained in the range of 0.1 mg / L to 1 g / L. The electroless nickel composite plating bath according to any one of claims 1 to 5, wherein in the molybdenum of (3), the molybdate is sodium molybdate, potassium molybdate or ammonium molybdate. The electroless nickel composite plating bath according to any one of claims 1 to 6, wherein in the antimony of (4), the antimonate is sodium antimonate, potassium antimonate or ammonium antimonate. The electroless nickel composite plating bath according to any one of claims 1 to 7, wherein the water-insoluble material (5) is water-repellent or hydrophobic fine particles. (5) The water-insoluble material is a fine particle formed of a material selected from the group consisting of fluororesin or fluorine compound, nylon, polyethylene, graphite, graphite fluoride, molybdenum disulfide, boron nitride and silicon carbide. The electroless nickel composite plating bath according to any one of claims 1 to 8. The electroless nickel composite plating bath according to any one of claims 1 to 9, wherein the water-insoluble material (5) is a fine particle of polytetrafluoroethylene. (1) water-soluble nickel salt,
(2) reducing agent,
(3) Selected from the group consisting of molybdic acid, molybdate and molybdate hydrate
    One or more kinds of molybdenum,
(4) Antimonic acid, antimonate, antimonate hydrate, antimonyl-L-
    One selected from the group consisting of tartaric acid and potassium antimonyl tartrate, or
    Two or more antimony,
(5) water-insoluble materials and
(6) Alloyed metal salt
Electroless nickel alloy composite plating bath containing The electroless nickel alloy according to claim 11, wherein the metal of the alloyed metal salt of (6) is iron, copper, tin, cobalt, tungsten, rhenium, manganese, palladium, vanadium, zinc, chromium, gold, silver or platinum. Composite plating bath. The electroless nickel alloy composite plating bath according to any one of claims 11 and 12, which is substantially free of mercury, arsenic, cadmium or lead. The electroless nickel alloy composite plating bath according to any one of claims 11 to 13, wherein the water-insoluble material (5) is water-repellent or hydrophobic fine particles. (5) The water-insoluble material is a fine particle formed of a material selected from the group consisting of fluororesin or fluorine compound, nylon, polyethylene, graphite, graphite fluoride, molybdenum disulfide, boron nitride and silicon carbide. Item 15. The electroless nickel alloy composite plating bath according to any one of Items 11 to 14. The electroless nickel alloy composite plating bath according to any one of claims 11 to 15, wherein the water-insoluble material (5) is a fine particle of polytetrafluoroethylene. An electroless nickel composite plating method using the electroless nickel composite plating bath according to any one of claims 1 to 10. An electroless nickel alloy composite plating method using the electroless nickel alloy composite plating bath according to any one of claims 11 to 16.