JPS6129733Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a plating device that stably and efficiently performs high-quality dispersion plating.

Dispersion plating, in which electrolytic plating is performed in a plating solution in which insoluble particles are suspended, and the particles are eutectoid in a dispersed state on the plating metal, is expected to improve the physical properties of the plating metal and has industrial potential as a method that can add new functions. has been done. For example, Ni plating in which MoSz or polytetrafluoroethylene is dispersed has lubricity, but AL ₂ O ₃ ,
Cu plating with TiO ₂ , BN, etc. dispersed has good mechanical strength, and Mo, WC, SiC, Al ₂ O ₃ etc.
It is known that platings such as Au, Ag, Rh, and Pt greatly improve electrical contact characteristics.

In order to use such dispersion plating industrially, it is fundamental to uniformly disperse particles at the desired concentration in the plating metal, and there is a strong need for a means to stably achieve this basic condition on a large scale. desired.

In other words, conventional plating equipment cannot homogenize the suspended state of particles over a wide range, so only a limited space within the plating tank is used, but the product quality fluctuates widely, making it difficult to use economically. It was difficult.

Dispersed particles have a different density from the plating liquid and are generally heavier, so they tend to concentrate downward, and this tendency is even more pronounced when the tank is deep. For this reason, even if a large agitator is used, the practical size of the tank is limited, and it is difficult to deal with this by simply increasing the agitator.
It is also uneconomical in terms of equipment, power, etc. It is also possible to circulate using a pump, but
In addition to extra equipment and power, suspended particles often cause non-negligible wear on the rotating parts of the pump. For example, for the purpose of improving mechanical strength and contact characteristics, hard or ultra-hard particles are used as described above, so the pump material is required to have corrosion resistance and wear resistance against plating liquid, resulting in an expensive pump.

In view of this, the present invention was developed as a result of various studies in order to stably realize the basic conditions for dispersion plating, and has developed a plating device that can perform high quality dispersion plating stably and efficiently. In a plating device in which a rotating stirring blade is installed in a plating tank filled with liquid, and the objects to be plated and an anode are installed, a flow passage with the upper part of the plating tank is provided below the rotating stirring blade, and a pump is generated by the rotation of the stirring blade. This feature is characterized in that the upper plating liquid is circulated downward through the flow passage.

This will be explained in detail using the drawings.

Figures 1a and b show an example of the device of the present invention (the anode and cathode, which are the objects to be plated, are omitted). In the figures, 1 is a plating tank, 2 is a plating liquid in which insoluble particles are suspended, and 3 is a plating liquid. A flow path 4 indicates a rotary stirring blade, a cylindrical tank is used as the plating tank 1, the inside is filled with a suspended plating liquid 2, and a stirring blade 4 attached to a rotating shaft 5 is inserted. An opening 6 is formed in the bottom plate 1a of the plating tank 1 under the stirring blade 4, and the plating tank 1 is inserted into a cylindrical outer tank 7 to form a flow path 3 between the two tanks 1 and 7. .

Figures 2a and 2b show another example of the device of the present invention, in which a square plating tank 1 is used, the inside is filled with suspended plating liquid 2, and stirring blades 4 attached to a rotating shaft 5 are used. insert. An opening 6 is formed in the bottom plate 1a of the plating tank 1 below the stirring blade 4, and the opening 6 and the upper part of the plating tank 1 are connected by a duct 8 to allow communication between the upper part of the plating tank 1 and the opening 6. Route 7 was formed.

In the device of the present invention, a stirring blade 4 is rotated in the direction of the arrow by a rotating shaft 5 to maintain suspension of insoluble particles, and at the same time, the insoluble particles are passed through an opening 6 under the stirring blade 4 into a flow path 3 by a pumping action caused by the rotation of the blade 4. The plating solution is sucked up and overflowed from the upper part of the plating tank 1 to circulate the plating solution. Therefore, the plating liquid is constantly circulated from the bottom to the top in the plating tank, and the suspension state in the plating tank is made uniform. In dispersion plating, where a homogeneous suspension state is an essential condition, mere mechanical stirring will cause temporal imbalance of the suspension state and gravitational action will inevitably affect the dispersion and eutectoid state of particles in the plating deposited metal. According to the device of the present invention, the above-mentioned requirements can be obtained most efficiently and economically. As shown in FIGS. 1 and 2, the bottom plate 1a of the plating tank 1 is formed into a conical shape, an opening 6 is provided in the center of the bottom plate, and a rotating stirring blade 4 is arranged above the opening 6, thereby further improving the plating tank. It is possible to homogenize the suspension state within.

Dispersion plating was performed using the apparatus of the present invention shown in FIGS. 1A and 1B to produce electrical contacts. The plating tank uses a cylindrical plating tank with an inner diameter of 500 mm and a height of 500 mm.
The bottom of the tank was shaped like a cone, and an opening with a diameter of 50 mm was provided in the center. This was inserted into an outer tank with an inner diameter of 580 mm, and a flow path was formed between the two tanks. A rotary blade with an outer diameter of 60 mm is placed above the opening in the plating tank, and rotated at a speed of 900 rpm, and 30 WC powder (powder diameter 1 μm or less) is placed in the plating tank.
Ag plating liquid (AgCN40g/
, KCN 50g/, K ₂ CO ₃ 1.5g/). Four Pt-plated Ti rods (diameter 20 mm, length 450 mm) are placed around the rotation axis of the rotor blade, and connected to the positive power supply as an anode, and concentrically outside of these are placed four Pt-plated Ti rods (diameter 20 mm, length 450 mm). rubber lined
A SUS cathode rack was placed and subjected to rotational vibration (frequency: 12 times/min, amplitude: 30 degrees).

Width 1.0mm, length 3.0mm, height 5.0mm on the body to be plated.
Length 340mm, width with contact blocks protruding every 20mm gap
Using a 12mm pressed material, it is made into a length of 360mm.
Three pieces were attached in parallel to a 40mm wide holding plate and fixed from above and below using pilot holes made in the pressed material and titanium hooks provided on the holding material. The titanium hook was connected to the negative terminal of the Metsuki power supply and also served as a power supply. A mask made of a thin plastic plate (thickness 0.8 mm) with a hole through which the surface of the contact block is exposed is placed on the surface of the fixed pressed material, and 12 of these are attached in parallel to the cathode rack and plated. Fixed at 10mm below the liquid level, current density 10A/
Plating was carried out at dm ² , and dispersion plating was carried out to a thickness of 15μ.

Assemble the relay using the dispersed plated contacts cut from the dispersed plated press material as shown below.
We conducted a switching test under the conditions of voltage 15V and current 15A,
We compared the lifespan of contacts plated dispersively at the top, middle, and bottom in the plating solution. The result is 650× at the top
10 ³ times, 700×10 ³ times in the middle part, and 700×10 ³ times in the lower part.

For comparison, the bottom opening of the plating tank of the above-mentioned device was closed and the pressed material was dispersed and plated in the same manner.
A similar test was carried out on the dispersion plating contacts which were cut into pieces. The results were 450×10 ³ times in the upper part, 650×10 ³ times in the middle, and 700×10 ³ times in the lower part.

As described above, the apparatus of the present invention enables high-quality dispersion plating to be carried out stably and efficiently, and has a significant industrial effect.

[Brief explanation of the drawing]

Figures 1 a and b show an example of the device of the present invention, a is a side sectional view, b is a plan view, and Figures 2 a and b are another example of the device of the present invention, a is a side view. Sectional view, b is a plan view. 1... Plating tank, 2... Plating liquid, 3... Distribution path, 4... Stirring blade, 5... Rotating shaft, 6... Opening, 7... Outer tank, 8... Duct.

Claims (1)

[Scope of utility model registration request] In plating equipment, a rotating stirring blade is installed in a plating tank filled with suspended plating solution, and a cathode and anode of the object to be plated are installed. A plating device for dispersion plating, characterized in that an upper plating liquid is circulated downward through a flow passage by a pump action caused by rotation of blades.