JPS62103388A - Cell for partial plating - Google Patents

Abstract

PURPOSE:To form a plating film having uniform quality to a very small part without uneven plating by impregnating an electroplating liquid to a multi- spaced liquid impregnating and holding body which is at least partly water repellent in an electrolytic plating liquid vessel and making electrolysis by an anode electrode and cathode electrode. CONSTITUTION:The anode electrode 2 and the cathode electrode 4 connected to a body 3 to be plated are disposed in the electrolytic plating liquid vessel 1 and further the multi-spaced liquid impregnating and holding body 5 of polyurethane, etc. which is partly water repellent is packed therein to constitute a cell for partial plating. The electroplating liquid is impregnated into the above- mentioned body 5 and electricity is conducted between the above-mentioned anode electrode 2 and cathode electrode 4 by a DC power source 6. The diffusibility of the plating liquid is thereby improved and the partial concentration of gaseous hydrogen is averted, by which the uneven plating is prevented and the plating film having the uniform quality to the very small part is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cell for electrolytically plating a small local area.

[Conventional technology]

As electronic devices become smaller, partial plating is sometimes applied to minute areas such as electrical contacts in order to maintain parts of the device components. In this method, an immobile f'ff such as graphite or absorbent cotton wrapped on the surface of the electrode is impregnated with a high ion eIf electrolytic plating solution, and a current is applied between the passive electrode and the object to be plated. It is plated.

[Problem that the invention seeks to solve]

This type of conventional method has the trouble of constantly shaking the surface of the object to be plated in order to remove hydrogen generated during plating from the interface and at the same time to homogenize the concentration of the plating solution. It also has the disadvantage that unnecessary parts are plated.

The present invention aims to eliminate these drawbacks by providing a cell for partial plating that allows rapid diffusion of the plating solution, avoids local concentration of hydrogen gas, and enables homogeneous plating in minute areas.

[Means for solving problems]

A partial plating cell to which the present invention is applied in order to solve the above problems will be explained with reference to FIG. 1 corresponding to an embodiment.

As shown in the figure, the partial plating cell is equipped with an anode electrode 2 and a cathode upper electrode 3, 4, and the electrolytic plating solution container l is impregnated with a solution at least partially water-repellent and multi-spaced. The holder 5 is impregnated with an electrolytic plating solution.

[Effect]

When electricity is supplied from a power source 6 connected to the anode electrode 2 and the cathode electrodes 3 and 4, the metal deposited on the cathode electrode 3 is plated. At this time, the electrolytic plating solution is impregnated into the imitation impregnated holder 5 and is not chemically adsorbed, so the plating solution has good diffusivity, and as the plating time progresses, the cathode electrode 3
The decrease in cations in the nearby electrolytic coating solution is likely to be supplied from other parts. Further, the generated hydrogen is not fixed between the interfaces, but is discontinuously adsorbed on the spatial surface of the imitation impregnated holder 5. Partial concentration of hydrogen gas can be avoided.

〔Example〕

An embodiment of the plating cell of the present invention will be described in detail below.

FIG. 1 is a diagram showing a partial plating cell of the present invention. As shown in the figure, the partial plating cell includes an anode electrode 2 and cathode electrodes 3 and 4. The anode electrode 2 is made of a passive material such as platinum. The cathode electrode 3 is an object to be plated on which minute portions are to be plated, and is in conductive contact with the cathode electrode 4 which is in a passive state. And a DC power source 6 is connected to the anode electrode 2 and the cathode electrode 4.
is connected. These electrodes are connected to the electrolytic plating solution container 1.
Ya is fired by. The electrolytic plating solution container l is a cylinder made of polyethylene, for example. Further, the electrolytic plating solution container 1 is filled with a liquid-impregnated holder 5, which is partially made of good wood and has many spaces. The liquid-impregnated holding body 5 is made of a porous water-absorbent material such as polyurethane, styrene, or silicone treated with a water simulating agent such as methylsiloxane, and can hold liquid in the porous space by capillary phenomenon. The continuous space of the liquid-impregnated holder 5 is impregnated with an electrolytic plating liquid.

In this embodiment, in order to perform rhodium plating, a solution of rhodium sulfate at a predetermined concentration is used as a plating solution.

With the above settings, voltage 12V from power supply 6, current density 1
．． When the current is applied at 24A/cm2, the object to be plated 3
is plated.

Figure 2 shows plating time (horizontal axis) and plating wave thickness (vertical axis)
This shows the relationship between (A) in the figure is a curve of the thickness of plating applied to the plated object 3 using the partial plating cell of the above embodiment. In addition, the same figure (b) shows an object to be plated 3 using a cell for partial plating in which a liquid-impregnated holder 5 which has not been treated with a porous water-absorbing material is impregnated with a plating solution.
This is the curve of the thickness of the plating applied to the surface.

As can be seen by comparing these curves, when the partial plating cell of the present invention is used, the gradient in which the plating thickness increases according to the energization time is larger, and the saturation state is reached more slowly. . That is, this shows that in the electrolytic makeup solution, the cations that are reduced in the vicinity of the object to be plated 3 are likely to be supplied to the maze from other parts.

In the above embodiment, an example is shown in which rhodium plating is performed using a rhodium sulfate solution as a plating solution, but rhodium plating may be performed using a rhodium phosphate solution.

In addition to rhodium plating, for example, gold plating, cadmium plating, and silver plating.

Ki, 9-1 solder plating, 6-4 solder plating, nickel
The partial Menkikawa cell of the present invention can be used for all '11i decomposition plating such as tin alloy plating and nickel plating.

〔Effect of the invention〕

As explained above, in the partial plating cell to which the present invention is applied, the plating solution has good diffusivity, and partial concentration of hydrogen gas can be avoided. Therefore, there is an advantage that uneven plating does not occur and a homogeneous plating film can be obtained in minute areas.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of an embodiment of a partial plating cell to which the present invention is applied, and FIG. 2 is a diagram showing the relationship between plating time and plating thickness. ■ Electrolytic plating solution container 2 Anode 1 shield 3 Plated object 4
, cathode electrode 5 , liquid-impregnated holder 6 DC power supply

Claims (1)

[Claims] 1. For partial plating, characterized in that an electrolytic plating solution container is provided with an anode electrode and a cathode electrode, and an electrolytic plating solution is impregnated into a multi-space liquid-impregnated holder at least partially water-repellent. cell.