JP2022091384A - Eutectoid plating solution - Google Patents

Abstract

To provide a novel eutectoid plating solution that can give a plated layer having excellent eutectoid properties even when using a high-pH plating solution.SOLUTION: The inventive eutectoid plating solution at least contains water, a Group 4 element-based coupling agent having a lactate group or a salt thereof, at least one silicon-based particles, and a metal source, and has a pH of 5.5-7.0.SELECTED DRAWING: None

Description

The present invention relates to an eutectoid plating solution.

In the manufacture of products in various fields, plating techniques such as electrolytic plating and electroless plating are widely used as techniques for forming a film on the surface of a member. Aspects of the conventional plating technique are disclosed in Patent Documents 1 and 2.

Further, in recent years, eutectic plating in which a plating reaction is performed with a plating solution containing wear-resistant particles such as silicon carbide particles is known. In such eutectoid plating, it is possible to impart new functions such as wear resistance, lubricity, and corrosion resistance to the plating film depending on the properties of the contained particles. It is often used for substrates that require wear resistance and hardness, such as connectors with high sliding frequency, and various means for such eutectoid plating have been proposed.

Patent Documents 3 and 4 disclose an eutectoid plating solution containing at least water, a Group 4 elemental coupling agent having an amino group, silicon carbide particles or silicon oxide particles, and a metal source.

Japanese Patent Application Laid-Open No. 2003-027202 Japanese Patent Publication No. 2008-516039 Japanese Unexamined Patent Publication No. 2020-180326 Japanese Unexamined Patent Publication No. 2020-117797

If sufficient dispersibility of the silicon carbide particles or the silicon oxide particles was not obtained, the silicon carbide particles were unevenly distributed in the obtained plating layer, or the plating layer could not be formed well. According to the means according to Patent Documents 3 and 4, sufficient dispersibility of the silicon carbide particles or the silicon oxide particles is obtained.

On the other hand, depending on the desired plating properties, it may be desirable to use a plating solution having a high pH. When such a plating solution was used, there was still room for improvement in eutectoidability even by the means according to Patent Documents 3 and 4.

Therefore, there is a need to provide a novel eutectoid plating solution that can provide a plating layer having good eutectoid properties even when a plating solution having a high pH is used.

As a result of diligent studies, the present inventors have found that the above problems can be solved by the following means, and have completed the present invention. That is, the present invention is as follows:
<Aspect 1> It contains at least water, a Group 4 element-based coupling agent having a lactate group or a salt thereof, silicon-based particles, and a metal source, and has a pH of 5.5 to 8.0.
Eutectic plating solution.
<Aspect 2> The eutectoid plating solution according to Aspect 1, wherein the Group 4 elemental coupling agent is a titanium coupling agent or a zirconium coupling agent.
<Aspect 3> The eutectoid plating solution according to Aspect 1 or 2, wherein the Group 4 elemental coupling agent has a hydroxyl group and a lactate group or a salt thereof.
<Aspect 4> An aqueous dispersion containing at least water, a Group 4 elemental coupling agent having a lactate group or a salt thereof, and silicon-based particles.

According to the present invention, it is possible to provide a novel eutectoid plating solution capable of providing a plating layer having good eutectoid properties even when a plating solution having a high pH is used.

《Eutectoid plating solution》
The eutectoid plating solution of the present invention is
It contains at least water, a Group 4 elemental coupling agent having a lactate group or a salt thereof, at least one of silicon particles, and a metal source, and has a pH of 5.5 to 8.0.
It is an eutectoid plating solution.

The eutectoid plating solution of the present invention may be an electrolytic plating solution or an electroless plating solution.

The content of silicon-based particles in the eutectoid plating solution is 0.001% by mass or more, 0.003% by mass or more, 0.005% by mass or more, and 0.01% by mass based on the entire mass of the eutectoid plating solution. % Or more, 0.03% by mass or more, 0.05% by mass or more, or 0.07% by mass or more, and 5% by mass or less, 3% by mass or less, 1% by mass or less, 0.5% by mass. Hereinafter, it may be 0.3% by mass or less, or 0.2% by mass or less.

The content of the Group 4 element-based coupling agent in the eutectoid plating solution is 0.001% by mass or more, 0.003% by mass or more, and 0.005% by mass or more based on the entire mass of the eutectoid plating solution. , 0.01% by mass or more, 0.03% by mass or more, 0.05% by mass or more, or 0.07% by mass or more, and 5% by mass or less, 3% by mass or less, 1% by mass or less, It may be 0.5% by mass or less, 0.3% by mass or less, or 0.2% by mass or less.

The ratio of the mass of the Group 4 element-based coupling agent in the eutectoid plating solution to the total mass of the silicon-based particles is 1% or more, 3% or more, 5% or more, 10% or more, 20% or more, 30. % Or more, 50% or more, 70% or more, 100% or more, 130% or more, 150% or more, 200% or more, 250% or more, or 280% or more, and 1000% or less, 900% or less, 800. % Or less, 700% or less, 600% or less, 500% or less, 400% or less, 350% or less, or 330% or less.

Further, the eutectoid plating solution may contain other particles.

The pH of the eutectoid plating solution may be 5.5 or more, 5.7 or more, 5.9 or more, or 6.0 or more, and 8.0 or less, 7.5 or less, 7.0 or less, 6 It may be 8.8 or less, 6.6 or less, 6.4 or less, or 6.2 or less.

Hereinafter, each component of the present invention will be described.

<water>
The water may be ion-exchanged water, distilled water, or the like.

<Group 4 elemental coupling agent>
The Group 4 elemental coupling agent is a Group 4 elemental coupling agent having a lactate group or a salt thereof. Here, in the present invention, the "Group 4 element-based coupling agent" has a hydroxyl group or a hydrolyzable group and a hydrophilic organic functional group bonded to a Group 4 atom, and is thereby originally present. It refers to a compound in which a hydroxyl group obtained by hydrolysis of a hydrolyzable group chemically bonds with an inorganic material and a hydrophilic organic functional group imparts hydrophilicity.

Group 4 elements are titanium, zirconium, hafnium, and rutherfordium. As the Group 4 element, titanium or zirconium, particularly titanium, is preferably used from the viewpoint of dispersibility.

The hydrolyzable group may be, for example, an alkoxy group, for example, a linear or branched alkoxy group having 1 to 10 carbon atoms, for example, an n-methoxy group, an n-ethoxy group, an n-propoxy group, an isopropoxy group, and the like. It may be an n-butoxy group, a sec-butoxy group, a tert-butoxy group, an n-pentoxy group, an isopentoxy group, a neopentoxy group, a tert-pentoxy group, a hexoxy group, an isohexoxy group and the like.

The lactate group has a structure of [-OCH (CH ₃ ) COOH]. The salt of the lactate group may be, for example, a lactate ammonium group [—OCH (CH ₃ ) COO (NH ₄ )] or the like.

The present inventors adsorb the above-mentioned Group 4 element-based coupling agent on the surface of the silicon-based particles and act as a dispersant, whereby these are dispersed in the plating solution and the silicon-based particles are well dispersed. It has been found that a plated layer can be formed.

By dispersing the above-mentioned Group 4 element-based coupling agent in the plating solution, silicon-based particles having an arbitrary average particle size, particularly silicon-based particles having an average particle size of 150 nm or less, can be satisfactorily dispersed. Therefore, when the plating layer is formed, a sufficient amount of silicon-based particles can be evenly distributed in the plating layer.

The Group 4 element-based coupling agent may have a hydroxyl group and a lactate group as a hydrophilic organic functional group or a salt thereof in the Group 4 element. In this case, the Group 4 elemental coupling agent is one hydroxyl group and three lactate groups or a salt thereof, two hydroxyl groups and two lactate groups or a salt thereof, or three and one lactate. It may have a group or a salt thereof, but it is preferable to have two or more hydroxyl groups from the viewpoint of improving the dispersibility of the silicon-based particles.

As the Group 4 element-based coupling agent having a hydroxyl group and a lactate group or a salt thereof, commercially available ones can be used, for example, Organtics TC-300, TC-310, ZC- of Matsumoto Fine Chemicals Co., Ltd. 300 and the like can be used.

<Silicon particles>
Silicon-based particles are generally particles composed of a silicon compound. The silicon-based particles may be, for example, silicon carbide particles or silicon oxide particles.

The average particle size of the silicon-based particles may be 10 nm or more, 20 nm or more, 30 nm or more, 40 nm or more, 50 nm or more, 60 nm or more, 70 nm or more, 80 nm or more, 90 nm or more, or 100 nm or more, and 100 μm or less, 50 μm or less. , 30 μm or less, 20 μm or less, 10 μm or less, 7 μm or less, 5 μm or less, 3 μm or less, 1 μm or less, 700 nm or less, 500 nm or less, 400 nm or less, 370 nm or less, 350 nm or less, 330 nm or less, 300 nm or less, 270 nm or less, 250 nm or less, 230 nm. Hereinafter, it may be 200 nm or less, or 150 nm or less. The average particle size referred to here is appropriately selected according to the size of the target silicon oxide particles, and in the case of particles smaller than approximately 1 μm, the average particle size of the histogram based on the scattering intensity distribution measured by the dynamic light scattering method (D50). ), And in the case of particles of 1 μm or more, it is the value of D50 calculated by the volume standard in the laser diffraction method. In particular, when the average particle size is 150 nm or less, the eutectoid property becomes better, and as a result, the wear resistance of the plating layer obtained by using the eutectoid plating solution of the present invention becomes better.

(Silicon carbide particles)
The silicon carbide particles may be commercially available silicon carbide particles.

(Silicon oxide particles)
The silicon oxide particles may be commercially available silicon oxide particles. Here, in the present invention, the "silicon oxide particles" mean particles containing silicon oxide in at least a part of the surface. Examples of such silicon oxide particles include pure silicon oxide particles, particles in which silicon oxide is present on the whole or a part of the surface, and the like.

Silicon oxide particles in which silicon oxide is present on the whole or a part of the surface can be obtained, for example, by oxidizing the silicon carbide particles. The content of silicon oxide in such silicon oxide particles is 0.01% by mass or more, 0.1% by mass or more, 1% by mass or more, 3% by mass or more, 5% by mass or more, 7% by mass or more, and 10% by mass or more. , 15% by mass or more, 20% by mass or more, 25% by mass or more, or 30% by mass or more, and 99% by mass or less, 95% by mass or less, 90% by mass or less, 80% by mass or less, 70% by mass. Hereinafter, it may be 60% by mass or less, 50% by mass or less, 45% by mass or less, 40% by mass or less, or 35% by mass or less. This content can be measured, for example, by measuring the mass change before and after the oxidation of silicon carbide.

<Metal source>
The metal source may be in various forms depending on the metal to be the plating layer, the mode of plating, and the like. The metal source is not particularly limited, for example, a metal salt of a metal to be a plating layer, for example, an inorganic acid salt such as a sulfate, a hydrochloride, a pyrophosphate, a sulfamic acid, an organic acid salt such as a cyanide salt, or the like. Can be used.

The metal to be used as the plating layer may be, for example, copper, nickel, chromium, zinc, tin, silver, gold or the like.

<Other ingredients>
As other components, for example, a pH adjuster, a pH buffer, a brightener and the like can be used.

Further, particularly in the case of an electrolytic plating solution, the eutectoid plating solution may contain an electrolyte.

Further, particularly in the case of an electroless plating solution, the eutectoid plating solution may contain a reducing agent. Examples of the reducing agent include sulfates of alkali metals or alkaline earth metals, hydrochlorides, pyrophosphates, phosphinates, sulfates, inorganic acid salts such as tetrahydroborate, and organic acid salts such as cyanide salts. Can be used. Further, as the reducing agent, for example, dimethylamine borane, hydrazine, titanium trichloride and the like can be used.

Further, particularly in the case of an electroless plating solution, the eutectoid plating solution may contain a complexing agent. As the complexing agent, for example, carboxylic acids such as acetic acid, lactic acid, oxalic acid, malonic acid, malic acid and tartaric acid, amino acids such as glycine, alanine and asparagine can be used.

《Water dispersion》
The aqueous dispersion contains at least water, a Group 4 elemental coupling agent having a lactate group or a salt thereof, and silicon-based particles. This aqueous dispersion may be an aqueous dispersion for producing an eutectoid plating solution.

The aqueous dispersion can be produced, for example, by stirring and mixing water, a Group 4 element-based coupling agent having a lactate group or a salt thereof, and silicon-based particles, and dispersing this with a bead mill or the like.

The content of silicon-based particles in the aqueous dispersion is 0.1% by mass or more, 0.3% by mass or more, 0.5% by mass or more, 1% by mass or more, and 2 based on the entire mass of the aqueous dispersion. It may be 50% by mass or more, 3% by mass or more, 5% by mass or more, or 7% by mass or more, and 50% by mass or less, 40% by mass or less, 30% by mass or less, 25% by mass or less, 20% by mass or less, It may be 15% by mass or less, or 13% by mass or less.

The content of the Group 4 element-based coupling agent in the aqueous dispersion is 0.1% by mass or more, 0.3% by mass or more, 0.5% by mass or more, and 0, based on the entire mass of the aqueous dispersion. It may be 7% by mass or more, 1% by mass or more, 2% by mass or more, 3% by mass or more, 5% by mass or more, or 7% by mass or more, and 50% by mass or less, 40% by mass or less, 30% by mass. Hereinafter, it may be 25% by mass or less, 20% by mass or less, 15% by mass or less, or 13% by mass or less.

<Other particles>
Examples of other particles include Al ₂ O ₃ , Cr ₂ O ₃ , Fe ₂ O ₃ , TiO ₂ , ZrO ₂ , ThO ₂ , CeO ₂ , BeO ₂ , MgO, CdO, diamond, SiC, TiC, WC, and the like. VC, ZrC, TaC, Cr ₃ C ₂ , B ₄ C, BN, ZrB ₂ , TiN, Si ₃ N ₄ , WSi ₂ , MoS, WS ₂ , CaF ₂ , BaSO ₄ , SrSO ₄ , ZnS, CdS, TiH ₂ , NbC, Cr ₃ B ₂ , UO ₂ , CeO ₂ , graphite, graphite, glass, kaolin, corundum, dye and the like can be used. Further, PTFE, polystyrene, polypropylene, polycarbonate, polyamide, polyacrylonitrile, polypyrrole, polyaniline, acetyl cellulose, polyvinyl acetate, polyvinyl butyral, or a copolymer (polymer of methyl methacrylate and methacrylic acid) can also be used. In addition, these other particles can be used alone or in combination.

<< Manufacturing method of eutectoid plating solution >>
The eutectoid plating solution can be produced by a method including mixing the above-mentioned aqueous dispersion and a metal plating solution. In this case, the content of the aqueous dispersion is 0.1% by mass or more, 0.3% by mass or more, 0.5% by mass or more, or 0.7% by mass or more based on the total mass of the eutectoid plating solution. It may be 10% by mass or less, 7% by mass or less, 5% by mass or less, 3% by mass or less, or 2% by mass or less.

<Metal plating solution>
The metal plating solution contains at least a metal source. Further, the metal plating solution may contain other components mentioned with respect to the eutectoid plating solution. As the metal plating solution, a commercially available metal plating solution can be used by diluting it with, for example, a predetermined amount of distilled water, if necessary, based on the instructions of the supplier. .. In the following, the "metal plating solution" refers to the metal plating solution immediately before being mixed with the above-mentioned aqueous dispersion, that is, the metal plating solution after dilution when diluted.

The pH of the metal plating solution may be 5.5 or more, 5.7 or more, 5.9 or more, or 6.0 or more, and 8.0 or less, 7.5 or less, 7.0 or less, 6. It may be 8 or less, 6.6 or less, 6.4 or less, or 6.2 or less.

The metal plating solution contains phosphorus in an amount such that the phosphorus content of the obtained plating layer is 7% by mass or less, 6% by mass or less, 5% by mass or less, 4% by mass or less, or 3% by mass or less. If so, the pH of the metal plating solution tends to be in the above range, so that the configuration of the present invention is useful. Further, according to this content, the hardness and wear resistance of the obtained plating layer can be increased. This content may be more than 0% by mass, 0.1% by mass or more, 0.5% by mass or more, 1% by mass or more, or 2% by mass or more.

The present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

<< Preparation of eutectoid plating solution >>
<Example 1>
10 parts by mass of silicon oxide particles having an average particle diameter of 100 nm obtained by oxidizing silicon carbide particles, a titanium lactate ammonium salt (organic TC) referred to in Table 1 as a lactate group-containing titanium coupling agent (TiCP) -A. -300, Matsumoto Fine Chemical Co., Ltd., active ingredient 44%) 1.0 part by mass, and 89.0 parts by mass of ion-exchanged water were stirred and mixed to make a uniform state, and then this was put into a paint shaker (diarconia with a diameter of 0.3 mm). The aqueous dispersion of Example 1 was prepared by performing a dispersion treatment using beads) with a dispersion time of 2 hours. The content of silicon oxide in the silicon oxide particles obtained by oxidizing the silicon carbide particles was 40% by mass.

<Examples 2 to 11, Comparative Examples 1 to 7 and Reference Example>
Water dispersions of Examples 2 to 11, Comparative Examples 1 to 7 and Reference Examples were prepared in the same manner as in Example 1 with the configurations shown in Table 1.

The details of the other dispersants mentioned in Table 1 are as follows:
Lactate group-containing TiCP-B: Titanium lactate (Organix TC-310, Matsumoto Fine Chemical Co., Ltd., active ingredient 41%)
Zirconium Group-Containing Zirconium Coupling Agent (ZrCP): Zirconium Lactate Ammonium (Organix ZC-300, Matsumoto Fine Chemical Co., Ltd., 12% Active Ingredient)
Silicon-based surfactant: Water-based silicon-based surfactant (BYK-349, BYK, 100% active ingredient)
Anionic surfactant: Wet dispersant for water system (DISPERBYK-2015, BYK, 40% non-volatile content)
Amino group-containing TiCP: Titanium diethanol aminate (Organic TC-500, Matsumoto Fine Chemical Co., Ltd., 70% active ingredient)

Further, regarding the morphology of the silicon-based particles shown in Table 1, the silicon oxide particles obtained by oxidizing the silicon carbide particles are referred to as "surface oxidation", and the pure silicon oxide particles are referred to as "oxidation". ", And the silicon carbide particles are referred to as" carbonized ".

<< Measurement of average particle size of silicon-based particles in an aqueous dispersion >>
The average particle size of the silicon-based particles in each of the obtained aqueous dispersions was measured by a dynamic light scattering method.

<< Preparation of plating solution and plating layer >>
1 part by mass of each of the prepared dispersions was mixed with 99 parts by mass of the plating solution to prepare an eutectoid plating solution. Then, the pH of the prepared plating solution was measured.

Here, in Table 1, what is referred to as "high pH plating solution" is emplate NI-426 (Meltex, Inc., phosphorus content of the obtained plating layer is 1 to 3% by mass) in a predetermined amount. The ones diluted with distilled water and referred to as "low pH plating solution" are SC-93-0 (Japan Kanigen Co., Ltd., phosphorus content of the obtained plating layer 9 to 10% by mass). ) Is diluted with a predetermined amount of distilled water. The pH of the high pH plating solution and the low pH plating solution was 6.2 and 4.5, respectively.

Using each of the prepared eutectoid plating solutions, an iron substrate having a thickness of 500 μm was coated with a plating layer by electroless plating.

<Evaluation of eutectoid state>
The cross section of the coated plating layer was observed with an electron microscope, and the eutectoid state was evaluated. The evaluation criteria are as follows:
A: A sufficient amount of silicon-based particles are evenly present.
B: A sufficient amount of silicon-based particles are present, but they are slightly unevenly distributed.
C: Silicon-based particles are not observed, or are present but unevenly distributed, or the amount is not sufficient.

Table 1 shows the configurations and evaluation results of Examples and Comparative Examples. In Table 1, the ratio of the mass of the Group 4 element-based coupling agent in the eutectoid plating solution to the mass of the silicon-based particles is referred to as "D / P".

From Table 1, when a plating solution having a high pH was used, the average was obtained in the aqueous dispersions of Examples 1 to 11 using the Group 4 elemental coupling agent containing a lactate group or a salt thereof. When either the silicon-based particles having a particle diameter of 100 μm or 1000 μm are used, the silicon-based particles are well dispersed in the aqueous dispersion, and the aqueous dispersion is mixed with a commercially available plating solution and coagulated. It can be understood that when it is used as a plating solution, it shows good eutectoidity.

On the other hand, in the aqueous dispersions of Comparative Examples 1 to 6 using a silicon-based surfactant, an anionic surfactant, and a Group 4 element-based coupling agent containing no lactate group or a salt thereof, When either silicon-based particles having an average particle diameter of 100 nm or 1000 nm were used, the silicon-based particles were not well dispersed in the aqueous dispersion, and the aqueous dispersion was mixed with the low phosphorus plating solution. The eutectoid property was not good when it was used as an eutectoid plating solution.

In addition, referring to the results of Comparative Example 7 and Reference Example, when a plating solution having a low pH is used, the eutectoid property is good when a titanium coupling agent containing a lactate group or a salt thereof is used. On the other hand, when a titanium coupling agent containing an amino group was used, the eutectoid property was good.

Claims (4)

It contains at least water, a Group 4 elemental coupling agent having a lactate group or a salt thereof, silicon particles, and a metal source, and has a pH of 5.5 to 7.0.
Eutectic plating solution. The eutectoid plating solution according to claim 1, wherein the Group 4 elemental coupling agent is a titanium coupling agent or a zirconium coupling agent. The eutectoid plating solution according to claim 1 or 2, wherein the Group 4 element-based coupling agent has a hydroxyl group and a lactate group or a salt thereof. An aqueous dispersion containing at least water, a Group 4 elemental coupling agent having a lactate group or a salt thereof, and silicon-based particles.