JPS60218494A - Pulse plating method - Google Patents

Abstract

PURPOSE:To improve the work efficiency by supplying electric current in the negative direction so as to eliminate concn. polarization in an electrolytic soln. every period in which electric current in the positive direction is not supplied. CONSTITUTION:A control circuit 12 makes switches 16a, 16b off when switches 15a, 15b are made on, and it makes the switches 15a, 15b off when the switches 16a, 16b are made on. All of the switches 15a, 15b, 16a, 16b can be made off. By this change-over the direction of electric current supplied to electrodes 19a, 19b is changed and the electric current is interrupted. When electric current 2 in the negative direction is supplied in a period in which electric current 1 in the positive direction is not supplied, concn. polarization produced during the supply of the electric current 1 can be rapidly eliminated. In addition, the interruption time T4 can be shortened. Since large electric current can be supplied by eliminating concn. polarization, the working efficiency is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a pulse plating method suitable for forming an amorphous alloy film.

[Prior art]

The mainstream of conventional plating methods has been continuous direct current electroplating, in which a direct current is continuously supplied to an electrode provided in an electrolytic solution. In recent years, the usefulness of amorphous alloys has attracted attention, and various methods have been proposed to form amorphous alloy films by plating, but this requires supplying a large current to randomize the movement paths of ions in the electrolyte. There is a need.

However, conventional continuous direct current electroplating cannot supply a large current because concentration polarization occurs in the electrolyte. For this reason, a pulse plating method has been proposed in which a DC current is supplied during a supply period T1 and the current supply is cut off during a non-supply period T2, as shown in FIG. According to this method,
Since the concentration polarization is eliminated during the period when no current is supplied, it becomes easy to supply a large current, and crystal nuclei are generated randomly at a high speed, making it possible to obtain a fine metal composition.

However, since the current is not supplied during the non-supply period, it takes a long time to form the required film thickness, resulting in poor working efficiency.

[Object and structure of the invention]

Therefore, an object of the present invention is to provide a pulse plating method that can improve work efficiency.

In order to achieve such an object, the present invention supplies a current flowing in the opposite direction to the current supply period during each non-supply period during pulse plating. Hereinafter, the present invention will be described in detail using drawings showing embodiments.

〔Example〕

FIG. 2 is a diagram showing a current supply method for realizing the pulse plating method according to the present invention. In the figure, 1 is a positive direction current, 2 is a negative direction current, 11 is a current value of positive direction current 1, I2 is a current value of negative direction current 2, T4 is a supply period of negative direction current, and T5 is a current interruption period. It is.

In this way, by supplying the negative direction current 2 during the non-supply period of the positive direction current 1, the concentration polarization that occurs when the positive direction current is supplied can be rapidly eliminated, so the current cutoff period T5 can be shortened, and the unit time It is possible to increase the number of positive direction pulses that can be supplied within the same period. Therefore, the time required to form the required film thickness is shorter than that of the conventional method. Also,
Concentration polarization can be quickly eliminated, allowing large currents to flow, and switching the direction of the current makes the movement of ions random, resulting in a uniform and flat layer thickness and the formation of crystals. Since the metal can be precipitated in the state of a nucleus without any formation, it becomes possible to plate an amorphous alloy layer.

In addition, positive direction current 1, negative direction current 2, current supply period TI
, T4, and the current interruption period T5 vary depending on the plating conditions, and the negative direction current 2 is adjusted to an optimum value that is necessary and sufficient to eliminate concentration polarization in the electrolytic solution. In addition, in the conventional pulse repetition cycle, the period T3 in FIG. 1 was required to eliminate concentration polarization, but in this invention, the concentration polarization can be rapidly eliminated by the negative direction current 2, so the period T3 is required in order to eliminate concentration polarization. The period can be shortened to T6.

FIG. 3 is a circuit diagram for supplying the current shown in FIG. 2,
The control circuit 12 turns on the switches 15m and 15b' and turns off the switches 16m and 16b, or turns on the switches 16m and 16b and turns off the switch 15m,
By switching the state of turning off the electrode 15b, the direction of the current supplied to the electrodes 19m and 19b is changed, and
The current is cut off by turning off all the switches 15a, 15b, 15c, and 15d. In addition, 1
0 is a DC power supply, 11 is a capacitor, 13m and 13b are resistors, 11 is a container, and 19a and 19b are electrodes.

In addition, in FIG. 3, the switches 15a, 15b, 16m,
Although the current is turned on and off by 16b, this may be done by a swiveling conductor switching element, etc., and the circuit is not limited to that shown in FIG. 3, but the point is that it can supply the current shown in FIG. Magnitude of negative direction current I2, period T
I, T4. The circuit is not limited to this one as long as T5 can be adjusted to meet the above conditions.

〔Effect of the invention〕

As explained above, the pulse plating method according to the present invention has the following effects since the negative current is supplied after the positive current is supplied.

1) Concentration polarization can be rapidly eliminated.

2) Can increase forward current.

3) The repetition period of positive direction current can be shortened.

4) Improved work efficiency.

5) Ion movement can be made random.

6) The thickness of the plating layer becomes uniform and flat.

7) An amorphous alloy layer is obtained.

[Brief explanation of the drawing]

Figure 1 is a current waveform diagram in the conventional pulse plating method.
FIG. 2 is a current waveform diagram in the pulse plating method according to the present invention, and FIG. 3 is a circuit diagram of a circuit that generates the current shown in FIG. 2. 1... Positive direction current, 2... Negative direction current, 10...
...DC power supply, 11...capacitor, 12...
・Control circuit, 13a t 13b...Resistance, 15m
+15b, 16m, 16b I e j + switch,
17.・---・Container, 18... Electrolyte, 19m, 1
9b...electrode. Patent applicant: Mitsui Engineering & Shipbuilding Co., Ltd. Agent: Kazutaka Yamakawa (I7λ2)

Claims (1)

[Claims] In a pulse plating method in which plating is performed by supplying an intermittent positive current to an electrode provided in an electrolytic solution, a negative current is supplied every time the positive current is not supplied, and the negative current is A pulse plating method characterized in that the value is necessary and sufficient to eliminate concentration polarization in an electrolytic solution that occurs when current is supplied.