JPH0425648Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Purpose of the Invention] Industrial Application Field The present invention relates to an apparatus for measuring the local current density of a surface to be treated which is subjected to an electrolytic treatment such as electroplating.

Prior Art When performing electrolytic treatments such as electroplating and electrolytic polishing, it is essential to adjust the current density of the surface to be treated within an appropriate range in order to obtain a good electrolytically treated surface. In order to know the current density in such electrolytic treatment, there is a method of calculating it from the area of the surface to be treated and the total current value. There is a problem in that the current is concentrated and only a small amount of current flows to the recesses or the back surface, so it is not possible to obtain a good electrolytically treated surface just by knowing the average current density as described above.

Therefore, when performing electrolytic treatment, it would be possible to know the local current density at different locations on the contact surface between the conductor to be treated and the electrolytic bath.
This should make it possible to perform electrolytic treatment efficiently and with excellent results by adjusting the electrolytic treatment conditions, the shape of the counter electrode, the relative positional relationship with the counter electrode, etc. However, even if there is a laboratory measurement method for determining the local current density of a liquid-contacted surface, the reality is that there is still no measurement method that can be used in industrial operations. Ta.

In contrast, one of the inventors of the present invention proposed a bipolar electrode type sensor in which a pair of mutually insulated conductor electrodes are arranged facing each other at a predetermined distance, and the sensor is placed close to the wetted surface of the conductor to be measured for current density. The sensor is placed in an electrolytic solution, and the potential gradient proportional to the current density in the solution generated by the current flowing through the electrolytic solution is detected as the potential difference between the electrodes of the sensor. The current density in the liquid near the liquid contact surface of the conductor to be measured is determined by substituting it into the potential difference-current density function obtained by measuring the liquid, and from this, the current passing through a specific point on the liquid contact surface is determined. It has been found that a means for approximately measuring the density of is industrially practical. He then invented a current density measuring device based on this principle and filed a separate patent application (Japanese Patent Laid-Open No. 62-27655).

Problems to be Solved This current density measuring device includes a sensor having a conductor disposed at its tip facing each other at a distance, an electric wire that derives the potential difference between the conductors as a signal, and an output that amplifies and displays the signal. It consists of equipment. and,
The measurement accuracy of the current gradient obtained by such a measuring device is determined by fixing the electrode attached to the sensor in a position that maximizes the potential gradient at a position close to the wetted surface of the conductor to be measured. This can only be ensured by implementing the following.

However, the shape of the conductor to be measured is not necessarily simple, and positioning the sensor is not easy when attempting to accurately measure current gradients in many parts of a conductor with a complex surface shape. Furthermore, it is not easy to fix the sensor in a position where the potential gradient is maximum, and in some cases, it has been impossible to even bring the electrode of the sensor close to the part to be measured.

Furthermore, if the electrode of the sensor is brought too close to the measurement target site, the current distribution will be disturbed, resulting in a decrease in the accuracy of the current density measurement value.

Therefore, when measuring the current density on the liquid contact surface of a conductor with a complex surface shape, the present invention allows electrodes to be easily brought close to each of various parts, and even if the electrodes are brought close, measurement is not possible. The present invention aims to provide a sensor for measuring current density without reducing accuracy.

[Structure of the idea]

Means for Solving the Problems The object of the present invention as described above is to provide two wetted electrodes insulated from each other at the tip of an insulating cylindrical body. are arranged oppositely at a predetermined distance in the length direction of a cylindrical body, and at least one of them is provided so as to surround the cylindrical body in an annular manner. This is achieved by using a sensor for measuring current density.

Hereinafter, the sensor of the present invention will be explained with reference to the drawings. 1 is the base of an electrically insulating cylindrical body, and 2 is an extension of the cylindrical body. The extension part 2 is formed into an elongated shape by embedding two mutually insulated conductive wires 3 and 3' in a soft insulating material 4. Annular liquid contact electrodes 5 and 6 are fitted at positions 5 mm and 10 mm away from the tapered tip 2a of the extension part 2 so that their outer surfaces are exposed on the side surfaces of the extension part 2, respectively. It is connected to conductors 3 and 3'.

The base 1 of the cylindrical body has a hollow cylindrical shape, and a two-core insulated wire 7 is provided passing through the inner space of the base 1, and each core wire has a conductive wire 3,
3'. An insulated wire 7 is led out from the rear end of the base 1 so that an electrode potential can be achieved for an external instrument.

These liquid contact electrodes 5 and 6 both have a liquid contact surface on the side when viewed from the axis, but the electrode 5 near the tip may be provided at the tip instead of on the side. In this case, there is an advantage that in addition to being able to measure the potential difference in the liquid, it is also possible to measure the electrical difference between the conductor to be measured and the liquid by bringing the electrode 5 into contact with the conductor to be measured. There is a disadvantage that it is difficult to ensure the accuracy of the distance from the liquid contact surface to the current density measurement point.

The wetted electrodes 5 and 6 are made of a corrosion-resistant metal such as platinum, or a metal of the same type as the ions contained in the electrolyte, and are made of a metal that will not contaminate the electrolyte even if eluted. It is desirable that there be.

Further, it is preferable that the extension part 2 is flexible, and if once bent, the state is maintained by internal friction, only the extension part 2 can be bent at various angles. This makes it easier to measure liquid contact surfaces with complex shapes.

Function Since the current density measuring sensor of the present invention is constructed as described above, the tip portion provided with the liquid contact electrodes 5 and 6 is arranged perpendicular to the liquid contact surface of the conductor to be measured. This device measures the electrical difference in a liquid, and if the tip is made of an insulator, the measurement position is accurately regulated by making the measurement with the tip in contact with the wetted surface, and a constant value is measured. The current density at can be easily determined.

[Effect of idea]

The sensor for measuring current density on the surface of a conductor in contact with liquid according to the present invention has a ring-shaped liquid contact electrode surrounding the tip of the cylindrical sensor, so the measurement position can be accurately regulated when measuring current density. In addition, the tip of the sensor can be positioned perpendicular to the surface of the conductor in contact with the liquid, so that the current distribution in the liquid is not disturbed. Therefore, it has become possible to measure local current density with high precision.

[Brief explanation of the drawing]

The drawing is a front view showing a partial cross section of a sensor for measuring current density on a surface of a conductor in contact with liquid according to the present invention. 1... Cylindrical body base, 2... Cylindrical body extension, 3,
3'...Conducting wire, 4...Insulating coating, 5, 6...Wetted electrode, 7...Insulated wire.

Claims (1)

[Scope of utility model registration request] Two liquid-contacted electrodes are provided at the tip of an insulating cylindrical body in a mutually insulated state, and the liquid-contacted electrodes are arranged opposite each other at a predetermined distance in the length direction of the cylindrical body. A sensor for measuring current density of a surface in contact with a conductor, characterized in that at least one of the two is provided annularly surrounding the cylindrical body.