JP3149285B2 - Ni-B electroless plating solution, plating bath or replenisher and 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 Ni-B electroless plating solution.
The present invention relates to an electroless plating solution capable of reducing defects of a Ni-B-based electroless plating film. The present invention also relates to a bath or a replenisher for the plating solution and a plating method.

[0002]

2. Description of the Related Art Ni-B plating has an Hv of 700 to 90.
It has much higher hardness than aluminum alloy of 0 and has better abrasion resistance than Ni-P plating layer, etc., but it has excellent sliding properties such as conformability and lubricity despite its high hardness. For this reason, it is used as a surface treatment for mechanical members in which aluminum alloy is used because of the need to reduce the weight of compressor vanes and the like.

[0003] Ni-B plating is a conventional method of degreasing a plating solution containing nickel sulfate, dimethylamine borane or the like.
It is performed by an electroless plating process in which a material such as a vane that has undergone a cleaning process is immersed.

[0004]

[0005] Conventional Ni-B-based plating films have more plating defects than Ni-P-based plating films. As a result of earnest research by the present inventors, this is because the former plating deposition rate is slower than the latter plating deposition rate, and it involves a lot of by-products of plating reaction such as hydrogen gas, decomposed organic substances, decomposed inorganic substances, waste products, etc. It is thought to be caused by

[0005] Further, Ni-B-based plating has a low plating deposition rate, so that the plating deposition state is greatly affected by variations in plating conditions, material surface conditions, and the like. As a result, the roughness of the plating film is large. Therefore, Ni-
Since the roughness of the B plating film is too large, the plating film is polished with a grindstone and then the roughness is adjusted by barrel polishing. However, when the roughness was adjusted and the surface of the plating film became flat, the above-mentioned plating defects became apparent, and after the barrel polishing, bulges or dents greater than the desired roughness occurred. Furthermore, in the conventional plating method, the rejection rate becomes extremely high when plating is repeatedly performed, so that the plating solution was discarded at that time, so that waste of resources was large. Therefore, an object of the present invention is to provide a Ni-B-based plating technique that can solve the above-mentioned problems.

[0006]

Means for Solving the Problems Ni-B according to the present invention
The system electroless plating solution contains nickel sulfate, a complexing agent, and a boron-containing organic reducing agent.
A solution for building bath or replenishment of this Ni-B type electroless plating solution, characterized by containing at least one selected from the group consisting of 0, 2 mg / l of 2,2 'thiodiethanol and thiodiglycolic acid. Is 0.9 to 0.9 parts by weight of at least one selected from the group consisting of 2,2 ′ thiodiethanol and thiodiglycolic acid per 100 parts by weight of nickel ions.
It is characterized by containing 4.0 parts by weight. Further, the Ni-B-based electroless plating method according to the present invention comprises nickel sulfate, a complexing agent, and a boron-containing organic reducing agent, and further contains 54 mg / l to 900 mg / l of 2,2 ′ thiodiethanol and thiodiethanol. A plating solution containing at least one selected from the group consisting of glycolic acid is brought into contact with the member to be treated, and nickel sulfate and a boron-containing organic reducing agent are replenished in accordance with the consumption of nickel and boron.
It is characterized in that one or two kinds selected from the group consisting of 2 ′ thiodiethanol and thiodiglycolic acid are replenished. Hereinafter, the configuration of the present invention will be described.

[0007] Nickel sulfate is a component having both stability and reducibility necessary for precipitating nickel by electroless. The complexing agent activates a metal base such as aluminum moderately and stabilizes and holds other components in the liquid. As the complexing agent, oxycarboxylic acid, monocarboxylic acid, aminocarboxylic acid and the like can be preferably used.

[0008] The boron-containing organic reducing agent reduces nickel sulfate and releases boron to deposit a Ni-B-based plating layer. Use of dimethylamine borane, dimethylamine diborane, dimethylamine triborane, or the like is required. Can be. Other various boron-containing organic reducing agents can be used, but the above-mentioned dimethylamine borane is preferable. The amounts of these components are not particularly limited, but need to be determined so that the above-mentioned reaction proceeds well. The preferred content in the plating solution to be brought into contact with the workpiece is
Nickel sulfate has a nickel ion concentration of 1 to 10 g /
l, preferably 5 to 7 g / l, and 10 to 150 g / l, preferably 50 to 1 g in a bath or replenisher.
20 g / l. One or more complexing agents are added, and the content thereof may be blended in a predetermined amount as usual, but the total content in the plating solution is preferably 2 to 15 g / l. The boron-containing organic reducing agent in the plating bath may be contained in an amount of 1 to 10 g / l.

The most characteristic feature of the present invention is that 54 mg /
1 to 900 mg / l of 2,2 ′ thiodiethanol and / or
Or containing thiodiglycolic acid,
If the amount is less than mg / l, many plating defects occur, and 900 mg
If it exceeds / l, the plating reaction becomes extremely slow, and the reaction is excessively suppressed, making the plating impractical. It is preferably from 60 mg / l to 540 mg / l, particularly preferably from 80 mg / l to 300 mg / l. If the amount of 2,2 ′ thiodiethanol and / or thiodiglycolic acid in the plating solution is not less than the above lower limit, it is considered that it is adsorbed on a trace plating surface to prevent precipitation of waste products and the like. Thiodiglycolic acid is 2,2 in the solution of the present invention.
It is thought that 2 ′ thiodiethanol is produced, and an equivalent action is obtained. The 2,2 ′ thiodiethanol content in the plating solution can be determined by an electrophoresis analyzer or the like. The concentration of 2,2 ′ thiodiethanol in the construction bath hardly changes in the plating solution even when the plating is deposited by a usual method. In the present invention, since the replenisher contains a predetermined amount of 2,2′-thiodiethanol or the like, the concentration in the plating solution can be increased.

The electroless plating is preferably carried out at a temperature of 35 ° C. or more and at a weak acidity, for example, at pH = 5.8 to 6.8. Further, the plating operation can employ any method such as a barrel method, an immersion method, and a spray method.

In the electroless plating solution, Ni-B plating is liable to be precipitated when all the above components are present. Therefore, the replenisher of the plating solution or the bath solution contains a single component or only a part of a plurality of components. It is necessary to contain it.
The present inventors have studied a replenisher or a bath solution containing 2,2 ′ thiodiethanol and / or thiodiglycolic acid and found that it is preferable to coexist with nickel sulfate. The use of this 2,2'-thiodiethanol-nickel sulfate-based solution allows the simultaneous supply of two components and is preferable from the viewpoint of preventing the decomposition of 2,2'-thiodiethanol. The concentration of each of these components is not particularly limited,
When the 2,2 ′ thiodiethanol is 0.9 to 4.0 parts by weight with respect to the nickel ion concentration of 100 parts by weight, the component concentration control of the plating solution becomes accurate. It is necessary that the boron-containing organic reducing agent is placed in the presence of the complexing agent as a separate solution from the above-mentioned replenisher or building bath solution to stabilize and prevent a reduction reaction from occurring during storage. . In addition to the complexing agent, if necessary, a stabilizer, ammonia or an ammonium salt, etc. can be added.

Further, the plating method according to the present invention comprises nickel sulfate, a complexing agent, and a boron-containing organic reducing agent,
Further, the member to be treated is brought into contact with a plating solution containing one or two kinds selected from the group consisting of 54 mg / l to 900 mg / l of 2,2 ′ thiodiethanol and thiodiglycolic acid, and nickel and boron. The method is characterized in that nickel sulfate and a boron-containing organic reducing agent are replenished in accordance with the exhaustion of water, and one or more selected from the group consisting of 2,2 ′ thiodiethanol and thiodiglycolic acid are further replenished. This method is the same as the conventional method in that nickel sulfate and boron-containing organic reducing agents are replenished in accordance with the consumption of nickel and boron to keep these components at a substantially constant amount. Not 2,2
'It differs greatly from the prior art in that the replenishment of thiodiethanol and / or thiodiglycolic acid gradually increases the concentration of this component during the plating operation. Thus, the plating operation with a low defect rate can be continued for a long time without rejecting the solution while repeatedly replenishing the solution at the time of building. However, the concentration of 2,2 ′ thiodiethanol or thiodiglycolic acid is 900
If the amount exceeds mg / l, problems such as a reduction in plating rate occur.

[0013]

As described above, by adding a predetermined amount of 2,2'-thiodiethanol and / or thiodiglycolic acid to the electroless plating solution, it is possible to prevent defects in the plating layer and to prevent blistering after polishing. Dents and the like can be extremely reduced. Hereinafter, the present invention will be described in more detail with reference to examples.

[0014]

EXAMPLE An aluminum vane used for a rotary compressor was alkali-degreased, washed with water, dried, and then dried.
IB-based electroless plating was performed. Plating Method 1 (Comparative Example) An aqueous solution containing a complexing agent was prepared in a plating tank.
Plating a replenisher (1) containing nickel sulfate and 2,2 ′ thiodiethanol (0.75 parts by weight per 100 parts by weight of nickel ions) and a replenisher (2) containing a complexing agent and dimethylamine borane The mixture was diluted with a predetermined amount of water in a tank, and the bath was built. As a result, the concentration in the plating solution was 6.0 g / l of nickel sulfate and 2,2 ′ thiodiethanol 45.
mg / l dimethylamine borane was 4.5 g / l.
The complexing agent used was oxycarboxylic acid and monocarboxylic acid, and the total concentration in the plating bath was about 10 g / l. By immersing a vane as a member to be processed in this plating solution, plating having a thickness of 30 microns was performed. Plating temperature is 60
° C and pH were 6.4. A small amount of a stabilizer was added to the replenisher (2). In addition, Ni in the plating solution
Was reduced by a predetermined amount, the replenisher (1) was replenished to restore the Ni concentration, and at the same time, the replenisher (2) was replenished so as to match the predetermined concentration. This is repeated for continuous use. Hereinafter, the case where 6 g / l of Ni is used is referred to as one turn for simplicity.

Plating method 2 The replenishing solution (1) was prepared in the same manner as in the replenishing solution (1) except that the concentration of 2,2 ′ thiodiethanol in the bathing solution was 90 mg / l (ie, the replenisher (1A) was doubled). , 2 ′ The plating was performed under the same conditions as in plating method 1, including the concentration of thiodiethanol. The replenisher (1A) used in the bath had a 2,2 ′ thiodiethanol concentration of 1.5 parts by weight with respect to a nickel ion concentration of 100 parts by weight.

Plating method 3 The concentration of 2,2 ′ thiodiethanol was 112.5 mg / l
(That is, 2.5 times)
The replenisher (1) contains the same 0.75 parts by weight of thiodiethanol as in plating method 1 until 1.5 turns, that is, until 9 g / l of total Ni in the plating solution is consumed,
After that, up to 2.0 turns, 2,2 ′ thiodiethanol was added 1.25 times (0.9375 parts by weight) of the replenisher (1
Replenishment was performed under the same conditions as in plating method 1 except that B) was used. The concentration of 2,2 ′ thiodiethanol in the plating bath is
About 180mg / l for 1.5 turns, about 2 for 2 turns
It became 08 mg / l.

Plating method 4 The concentration of 2,2 ′ thiodiethanol was 112.5 mg / l
A bath was prepared under the same conditions except that the bath was made up with a 2.5-fold replenisher (1C). As a replenisher to be replenished when Ni in the plating solution was reduced, 2,2 ′ thiodiethanol was used. Replenishment was carried out under the same conditions as in plating method 1, except that a replenisher (1A) with a 2-fold increase (1.5 parts by weight) was used. 2,
The concentration of 2 'thiodiethanol in the plating bath was about 247 mg / l for 1.5 turns and about 292 mg / l for 2 turns.
l. The replenisher (1C) used in the bath had a concentration of 2,2 ′ thiodiethanol of 1.875 parts by weight based on 100 parts by weight of nickel ions.

After the above plating, grinding stone polishing and barrel polishing are performed, the surface roughness in a portion where there is no bulge or dent of the plating is set to Rz 0.5 μm, and the plated surface is observed with a magnifying glass of 5 times. Those having one or more blisters or dents per vane were regarded as defectives, and the defect rate was determined.

The figure shows the test results described above. It is apparent from this figure that the defective rate of plating is remarkably reduced according to the method of the present invention.

Further, as another embodiment, 3.75 parts by weight of 2,2 'is added to 100 parts by weight of nickel ions.
Replenisher (1x) at a concentration of thiodiethanol (ie 5 times)
A bath was prepared using D), and Ni-B plating was performed up to 3 turns using the same replenisher (1D) for replenishment when consuming Ni. The concentration of 2,2 ′ thiodiethanol in the plating bath during three turns was about 900 mg / l. The defect rate was as low as the plating method 4 and extremely low.
When the above plating methods 2 to 4 were performed using a replenisher obtained by mixing thiodiglycolic acid with a nickel sulfate solution instead of 2,2 ′ thiodiethanol, almost the same results were obtained.

[0021]

As described above, Ni-B-based plating has a problem that there are many defective products because plating defects are easily generated. However, a plating solution to which 2,2′-thiodiethanol is added is used. Use can greatly reduce defects. Further, by replenishing 2,2 ′ thiodiethanol, aging of the plating solution is prevented, and continuous use is enabled. As described above, the present invention has a great advantage in terms of yield improvement and resource saving.

[Brief description of the drawings]

FIG. 1 is a graph showing a defective rate due to electroless plating.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshihiro Kaku 3-65 Midorigaoka, Toyota City, Aichi Prefecture Inside Daitoyo Kogyo Co., Ltd. (72) Inventor Takahiro Miyaji 6-100 Shinmeicho, Kariya City, Aichi Prefecture Inside Satetsu Carrier Co., Ltd. (72) Inventor Yutaka Nakagishi 4-7-10 Doshomachi, Chuo-ku, Osaka City, Osaka Prefecture Inside Okuno Pharmaceutical Co., Ltd. (56) References JP-A-2-19472 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C23C 18/00-18/54

Claims (3)

(57) [Claims] Claims: 1. A composition comprising nickel sulfate, a complexing agent, and a boron-containing organic reducing agent, and further comprising 54 mg / l to 900 mg.
An Ni-B-based electroless plating solution comprising one or two selected from the group consisting of / 2,2 'thiodiethanol and thiodiglycolic acid. 2. One or two selected from the group consisting of 2,2′-thiodiethanol and thiodiglycolic acid per 100 parts by weight of nickel ions in a concentration of 0.9 to 4.
A Ni-B-based electroless plating solution-building bath or replenisher, which contains 0 parts by weight. 3. A composition comprising nickel sulfate, a complexing agent, and a boron-containing organic reducing agent, further comprising 54 mg / l to 900 mg.
/ L of a plating solution containing at least one member selected from the group consisting of 2,2 ′ thiodiethanol and thiodicholic acid and a member to be treated, and nickel sulfate and nickel sulfate depending on consumption of nickel and boron. A Ni-B-based electroless plating method characterized by replenishing a boron-containing organic reducing agent and further replenishing one or two selected from the group consisting of 2,2'thiodiethanol and thiodiglycolic acid.