JP3247767B2 - Composite plating method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite plating method.

[0002]

2. Description of the Related Art Composite plating is also called eutectoid plating or dispersion plating, in which dispersant particles such as metal oxides, carbides and nitrides are dispersed in an electrolytic bath to perform electroplating. Are dispersed in a matrix metal and co-deposited on the substrate to be plated. Composite plating products have recently attracted attention due to the following various features not found in ordinary metal plating. That is, when composite plating is used for decorative plating, matte plating or metallic plating becomes possible, and industrially, wear resistance, lubricity, non-adhesion, mold release, corrosion resistance, heat resistance, and the like can be improved.

[0003]

However, when the dispersant particles are dispersed in the electrolytic bath, the specific gravity of the dispersant particles is larger than the specific gravity of the electrolytic solution, and the dispersant particles tend to settle. For this reason, many dispersant particles precipitate on the upper surface side of the substrate to be plated, and there is almost no dispersant particle on the lower surface side. In order to prevent this, a propeller stirrer is inserted into the electrolytic cell and the propeller is stirred by rotating it, or a plating solution is ejected from the lower center of the electrolytic tank by a pump, and the liquid is circulated by overflowing from the upper part and sucking by the pump. The plate pumper process (Plate Pumper Process), which uses a jet jet of electrolyte ejected from the small holes, moves the plate with many small holes horizontally provided near the bottom of the electrolytic cell up and down, and blows bubbles. And an ultrasonic method of stirring the inside of the electrolytic cell by ultrasonic waves. However, when the size of the electrolytic cell is increased on an industrial scale and when it is necessary to use large dispersant particles depending on the type of plating, there is a problem that the dispersant particles cannot be uniformly dispersed.

[0004] When vigorous stirring is carried out to uniformly disperse, there is a problem that the dispersant particles once deposited on the substrate to be plated are separated.

Further, when the dispersant particles are negatively charged, there is a problem that the particles are hardly deposited on the cathode and do not coeutect with the metal.

An object of the present invention is to provide a composite plating method using an electrolytic bath in which dispersant particles are uniformly dispersed with little stirring.

[0007]

The present invention provides a dispersant particle, a water-soluble or water-dispersible cationic resin having a polyamino structure, such as an acrylic resin, an alkyd resin, a silicone resin or a fluororesin, and a coupling agent. And an electrolytic solution obtained by dispersing a dispersant composition comprising:

Further, the present invention is characterized in that the coupling agent is a silane coupling agent represented by the formula (I).

[0009]

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[0010]

[0011]

According to the present invention, a dispersant composition in which dispersant particles, a cationic compound and a coupling agent have been subjected to a coupling treatment in advance is produced, and this is dispersed in an electrolytic solution.

As the coupling agent, a silane coupling agent represented by the formula (I) is preferable.
A titanate represented by the formula (IV) may be a coupling agent or the like.

[0013]

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(R ¹⁰ ) _a Ti (COOR ² ) _b ... (II) (R ¹⁰ ) _a Ti [PO ₂ (OR ² ) ₂ ] _b ... (III) (R ¹⁰ ) _a Ti (OR ² ) _B ) (IV) In the formulas (II) to (IV), R ¹ and R ² : an alkyl group a + b = 4 As the dispersant particles, the following commonly used dispersant particles can be used.

(A) Metal oxides α-Al ₂ O ₃ , γ-Al ₂ O ₃ , TiO ₂ , ZrO ₂ , Th
O ₂ , CeO ₂ , UO ₂ , BeO ₂ , MgO, CaO, Cr
₂ O ₃ , Eu ₂ O ₃ , Fe ₂ O ₃ , SiO ₂ (b) carbide SiC, WC, TiC, ZrC, VC, Cr ₃ C ₂ , B ₄
C, HfC, TaC (c) nitride α-BN, β-BN, Si ₃ N ₄ , AlN (d) boride CrB ₂ , ZrB ₂ , TiB ₂ , VB ₂ (e) silicide CrSi ₂ , MoSi ₂ , WSi ₂ (f) sulfide MoS ₂ , WS ₂ , NiS (g) Sulfate BaSO ₄ , SrSO ₄ (h) Particulate metal Cr, Ni, Co, Mo, W, Ti, V, Nb, Ta (i ) Others Graphite, diamond, silica fiber, kaolin, mica, glass, metal (Ca, Sr, Ba, Mg,
Ni) titanate, zirconate of the same metal, silicate of the same metal, inorganic pigment, carbon black, fluororesin,
Silicon resin Also as the cationic compound, water-soluble, water-dispersible acrylic resin having a polyamino structure, Alkit resin,
Silicon resin or fluorine resin is preferred.

As the electrolytic bath, Ni, Cu, Co, F
e, Cr, Au, Ag, Zn, Cd, Pb, Sn and other single electroplating baths, Ni-Co, Ni-Fe, Ni-M
An alloy plating bath of n, Ni-W, Pb-Sn or the like is exemplified.

The coupling agent 1 comprises a cationic compound 2
As shown in FIG. 1, a dispersant composition having a stable positive charge is formed in the plating bath by a chemical bond or a physical bond with the dispersant particles 3. Since the dispersant composition has a positive charge, it does not repel each other in the electrolytic solution and agglomerate, and migrates in the same direction as the metal ions in the electrolytic bath, and serves as a cathode to be plated. Absorbed strongly on the surface and taken into the metal plating film to complete the composite plating.

After the coupling agent, the dispersant particles and the cationic compound are mixed, the mixture is heated to carry out the above-mentioned coupling reaction, and is fixed to form a cake. The solvent added for this purpose is removed by washing with water, and used after being dispersed in an electrolytic solution.

[0019]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

(1) Synthesis of cationic compound Butyl cellosolve 10 was added to 40 parts of isopropyl alcohol.
The mixture was heated to about 75 ° C. in a four-necked flask equipped with a reflux condenser, a thermometer, a stirrer, and a dropping funnel. The mixture shown in Table 1 was continuously fed from the dropping funnel over 3 hours while stirring. Drip. After the completion of the dropwise addition, the reaction is continued for another 3 hours at the same temperature to synthesize a cationic polyaminoacrylic resin.

[0021]

[Table 1]

(2) Preparation of Dispersant Composition As a silane coupling agent, an isocyanate-functional silane (Y-9030 manufactured by Nippon Unicar Co., Ltd.) OCN
1 part by weight of —C ₃ H ₆ —Si (OC ₂ H ₅ ) ₃ , 10 parts by weight of the cationic compound prepared in (1), and Table 2
And 100 parts by weight of dispersant particles shown in (1), 20 parts by weight of ethyl acetate, and stirring at 110 ° C. for 4 hours.
Heat for 0 minutes to perform the coupling treatment. After cooling, the dispersant composition in the form of a sticky cake is pulverized finely, dispersed in 300 parts by weight of a 1% aqueous acetic acid solution using a homogenizer, and the solvent in the dispersant composition is washed. Next, this solution is filtered to synthesize a powdery dispersant composition.

EXAMPLE The dispersant composition prepared in (2) was dispersed in a Ni plating bath such that the amount of the dispersant particles contained therein became 50 g per liter of the electrolytic solution, and the cathode current density at a bath temperature of 50 ° C. 2A / d
At m ² , the mixture was stirred by using both air stirring (0.5 cc / min) and stirrer stirring (20 rpm) to perform Ni plating. The composition of the electrolytic solution is as follows.

NiSO ₄ .6H ₂ O 240 g / l NiCl ₂ .6H ₂ O 45 g / l H ₃ BO ₃ 35 g / l pH 4.5 After electroplating, the plating surface is observed with a microscope and the eutectoid state of dispersant particles Was examined. Table 2 shows the results.

Comparative Example Dispersant particles shown in Table 2 were dispersed at 50 g / l in a Ni plating bath, and electroplating was performed under the same conditions as in the example. Investigation was performed in the same manner, and the results are shown in Table 2.

[0026]

[Table 2]

From the results of the above Examples and Comparative Examples, it can be seen that in the composite plating method according to the method of the present invention, the dispersant particles are more eutectoid than in the conventional method.

[0028]

As described above, according to the present invention, since the dispersant particles are bonded to the cationic compound by the coupling agent, those having a large particle diameter and those having a large specific gravity do not precipitate. Since negatively charged particles can also be positively charged, they can be co-deposited with metal, and uniform composite plating can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a bonding state between a dispersant particle 3 and a cationic compound 2 by a coupling agent 1. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coupling agent 2 Cationic compound 3 Dispersant particle

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C25D 15/00 C25D 13/10

Claims (2)

(57) [Claims] 1. A dispersant composition comprising dispersant particles, a water-soluble or water-dispersible acrylic resin, alkyd resin, silicone resin or fluorine resin having a polyamino structure, and a coupling agent. A composite plating method using an electrolytic solution dispersed in an electrolytic bath. 2. The composite plating method according to claim 1, wherein the coupling agent is a silane coupling agent represented by the formula (I). Embedded image