JPS5848038B2 - Denkimetsukiho - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for electrodeposition of nickel-phosphorus alloy.
By using nickel sulfamate and sodium hypophosphite or sodium phosphite, it has become possible to obtain a film with good properties through efficient high current density processing.

In nickel K deposition, which has been widely used for a long time, liquids mainly composed of nickel sulfate and nickel chloride usually have many problems in terms of photoselectivity, stress, and strength unless an organic photoselector is added. It was not practical, and high-speed electrodeposition using high current density was also impossible.

Furthermore, the organic photoselectors used in the above liquids generally use additives containing sulfur, which has the disadvantage of deteriorating the heat resistance and touch resistance of the coating. Long-term reliability could not be achieved in a corrosive environment.

In place of this nickel sulfate-based solution, a nickel sulfamino acid solution is used as an electrolytic high-speed plating solution that does not use an organic photo-selective agent, but because it does not use an organic photo-selective agent, its strength is low. At present, it cannot be used for a very wide range of purposes.

Although it is possible to increase the strength by adding cobalt sulfamic acid to this sulfamic acid solution, there is a limit in terms of strength, and the addition of Co increases the price.

The present invention aims to eliminate the above-mentioned drawbacks, and by adding sodium hypophosphite or sodium phosphite to the nickel sulfamate solution, the following advantages arise.

■． Compared to electroless nickel plating solution, it is easier to control the amount of phosphorus and adjust the hardness.

2. Longer lifespan than electroless nickel plating solution.

3. High current density enables high-speed nickel-phosphorus alloy plating, and thick plating is also possible.

(e.g. electrodeposition rate of 400 μ/h at 40 A/di) 4. Harden by heat treatment (e.g. 400° Clhr).

5. It has better corrosion resistance than pure nickel and nickel-cobalt alloys.

6. Heat resistance is good because no organic photoselector containing sulfur is used to increase strength.

The reasons for limiting the components in the scope of this claim will be explained below.

The amount of sulfur amino acid nickel, which is the main component, is 200 to 8
The range was limited to 0 0 g/11, but the lower limit was set to 2
00g/11 was chosen because if the current density is less than IOA/dm2, the appearance level and pH value are likely to decrease, which is a feature of the present invention. is impossible.

In addition, the upper limit of the amount of sulfur amino acid nickel is 800 g.
/l because even if the concentration is increased beyond this, there is a limit to the electrodeposition speed of the bath, and losses due to pumping of the liquid during actual work increase, resulting in a decrease in overall efficiency.

On the other hand, although the sodium hypophosphite used to contain phosphorus was limited to a range of 0.05 to 20 g/l, the lower limit was set at 0.05 g/l because it is Even if the coating conditions are changed, it is difficult to secure a hardness of HV-300 or higher, and in order to put it into practical use as a Ni-P-based hard coating, it is necessary to contain more sodium hypophosphite or sodium phosphite. It is necessary.

Also, the upper limit was set to 209/l, which is 0.05g/l.
The hardness increases as the content increases from lj, but
If it exceeds 20 g/l, the HV-600 or higher will result, and the film itself will become extremely hard and brittle, making it unsuitable for practical use in various applications.

In addition, clouds and pits occur on the surface of the electrodeposited material, making it unsuitable for decorative purposes in particular.

Furthermore, there was a problem in that the electrodeposition stress became tensile, making it difficult to use, especially as an electroforming bath.

The reason why the precept of nickel chloride was limited to 5 to 20 g/l was because
This is because below 59/l, the dissolution of the anode plate is limited, polarization occurs, and the pH of the limbs gradually decreases.
This is because if it exceeds g/l, the electrodeposition stress becomes too high, making it particularly unsuitable for thick plating or electroforming.

The reason why the boric acid content was limited to 30-609/l was due to the pH.
The lower limit showing the effect as a buffering agent is 30 g/l, and 6
Even if the amount is increased to 0 Vl or more, there is no effect proportional to the amount, so there is no point in adding more than that amount.

Next, the component range of sodium lauryl sulfate is 0.1 to 1 g.
/It is limited to 0.1g of sodium lauryl sulfate.
If it is less than /l, pitting will occur on the plated surface, making it impossible to obtain a normal plated surface.

? Since the effect is the same even if the amount of calories added is 13 g/l or more, the amount was limited to 19 g/l.

Under the electrolytic conditions, the liquid temperature was limited to 50 to 70°C.

The reason for this is that if the liquid temperature is below 50°C, it is difficult to produce photo-selectivity on the plated surface, and on the other hand, if it is higher than 70°C, the sulfamic acid ions will begin to decompose, and the life of the liquid will be extremely shortened. .

Next, the reason why the current density is limited to 10 O A/dm2 or less is because this current density is the limit value at which a photo-selective surface can be obtained.

Further, the pH was limited to 3.5 to 5.5.

The reason is that when the pH is below 3.5, water decomposition due to the force of sulfamic acid ions progresses, resulting in a shortened solution life.

Furthermore, as the pH increases, there is a possibility that nickel hydroxide will precipitate due to variations in electrodeposition conditions, so the upper limit of pH was set at 5.5 as a safe value.

Actual cases are shown below.

Example 1 Nickel sulfur amino acid ・・・・・・・・・6 0
0 g/1 nitrous chloride...
...10g/l sodium hypophosphite...
・・・・・・0.5 g/1 boric acid
・・・・・・・・・4 0 g/1 Sodium lauryl sulfate ・・・・・・・・・0.3 g/1 Liquid temperature
......60°C current density ...10A7'
dm”pH ・・・・・・・・・
...4,0 When 60 μm of Ni was electrodeposited on a brass plate under these conditions, the micropicker hardness was HV450-55.
0. When it was heat treated for 400'CI hours,
}{V= 1 0 0 0.

Although this electrodeposited material was a Ni--P alloy, it was characterized by high elongation and low brittleness, unlike Ni--P produced by ordinary electroless plating.

The characteristics of this plating solution are high-speed nitrogen plating, high hardness, and good contact resistance and heat resistance, so its application range is wide, such as injection molds manufactured by electroforming, watch cases, etc. , parts for wristwatches, outer blades for electric razors manufactured by electroforming, coatings for scraping blades and inner blades, etc. can be considered.

Note that sodium hypophosphite and sodium phosphite have almost the same effect; as the amount of added calories increases, the hardness gradually increases, and the film exhibits tensile stress.

Claims (1)

[Claims] 1. 200 to 800 g/l of nickel sulfamate;
Sodium hypophosphite 0.05-20 g/l, nickel chloride 5-20 El/l, boric acid 30-60 E
l/It, with an electrolytic solution having a composition of 0.1 to 19/l of sodium lauryl sulfate, a liquid temperature of 50 to 70°C, and a current density of i1.
0 0A7'd m or less, pH 3. 5 ~5.
An electroplating method for a nickel-phosphorous alloy characterized by electrodeposition under conditions 5. 2 Nickel sulfamate 200-800 i/
11 and sodium phosphite 0.05-20i. #1 Nickel chloride 5-20 g/l, boric acid 30-60 9/
l, sodium lauryl sulfate 0.1 to 1 In an electrolytic solution having a composition of 9/13, the liquid temperature is 50 to 70°C, and the current density is 100.
person/bm or less, pH 3. 5 ~5. An electroplating method for a nickel-phosphorous alloy characterized by electrodeposition under conditions 5.