JPH09297118A - Corrosion measuring device for metallic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably and precisely measure corrosion by providing a Luggin tube in such a manner that the opposed position of its capillary-like tip part to a sample electrode is adjustable two-dimensionally and/or three-dimensionally. SOLUTION: A Luggin tube holder 41 has a holder body 43 for holding a Luggin tube 42 by a holding position regulating presser vis 44 in such a manner as to be position-adjustable in vertical direction (Z-direction). It has a flange base 45 for mounting and fixing the holder body 43 onto a prescribed part of a lid member 12. The base 45 can be mounted in such a manner as to be position-adjustable in longitudinal direction (X-direction) and lateral direction (Y-direction) to a sample electrode holder 21. To the exposed surface of the sample electrode of the sample electrode holder 21, the opposed space and opposed position of the capillary tip part 42a of the Luggin tube 42 held by the Luggin tube holder 41 can be regularly set with high precision to stably and precisely perform a corrosion measurement.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring corrosion of metal materials, and more particularly, to an apparatus for measuring corrosion.
The present invention relates to a corrosion measuring device for a metal material, which is capable of performing an electrochemical test method as a corrosion measuring method.

[0002]

2. Description of the Related Art Conventionally, a so-called electrochemical test method has been widely adopted for measuring corrosion of metal materials. That is,
In general, it is known that corrosion of metal materials in an aqueous solution proceeds by an electrochemical reaction. Regarding the electrochemical corrosion rate measurement using this electrochemical reaction, (a) measurement in a short time is required. It has various excellent features such as that it is possible, (b) quantification of corrosion rate is easy, and (c) instantaneous value of corrosion rate can be obtained. It is a measurement method. here,
The electrochemical corrosion rate can be easily obtained, for example, by measuring the polarization characteristics between the arranged electrodes.

6 (a) and 6 (b) are configuration explanatory views (FIG. 6 (a)) schematically showing the outline of a metal material corrosion measuring apparatus according to a conventional example adopting the electrochemical test method. FIG. 7 is an external perspective view (FIG. 7B), and FIG. 7 is a block diagram for explaining an outline of the case where polarization characteristics are measured by the potentiostatic method using the above corrosion measuring apparatus.

In these apparatus configurations shown in FIGS. 6 (a), 6 (b) and 7, the corrosion measuring apparatus has an upper opening which can be hermetically sealed by a lid member 102 to obtain a corrosive action in the internal sample chamber. It has a corrosion-resistant electrolytic bath 101 containing a sample solution 103 for Then, the lid member 10
2, a sample electrode holder 111 having a tip portion exposed and holding a sample electrode 112 made of a metal sample to be measured, and a counter electrode holder 121 having a counter electrode 123 made of a platinum electrode sealed and held in a counter electrode chamber 123 at the tip portion. , And a Luggin tube 131 having a capillary-shaped tip portion 131a formed therethrough. Here, the exposed sample electrode 112 and the sealed counter electrode 122 are connected to the sample solution 10.
3 and the capillary-shaped tip portion 131a of the Luggin tube 131 is opposed to the sample electrode 112 at a predetermined interval.

In addition, in the intermediate tank 141, which is separately provided and contains the KCl solution 142, the connecting tube 1 made of the reference electrode 151 and the glass tube taken out from the Luggin tube 131 is connected.
The ends of 32 are immersed in each, and the connecting pipe 10
The electrical connection is maintained by the liquid bridge that passes through the inside of 2. Further, for the inside of the electrolytic cell 101, a gas inlet pipe 1
Deoxygenated gas is fed by 61, and the gas discharge pipe 1
62 is water-sealed. In the figure, 171 is a thermometer provided for checking the temperature of the sample solution 103.

In order to perform the corrosion measurement using the corrosion measuring device having the above-mentioned structure, in this case, as is apparent from FIG. 7, the electrodes, that is, the sample electrode 112 and the counter electrode 1 are used.
The potentiostatic electrolysis device 181 is connected to the reference electrode 22 and the reference electrode 151, and the control device is operated to measure the polarization characteristics by the potentiostatic method suitable for measuring the corrosion system, as is well known. .

That is, in the present corrosion measuring apparatus, the temperature and atmosphere for obtaining the corrosive action are measured while the sample solution 103 is contained in the electrolytic cell 101 in which the counter electrode 122 and the Luggin tube 131 are arranged. After the conditions are adjusted, the sample electrode 112 is inserted and immersed in the sample solution 103, and the spontaneous corrosion potential measurement is immediately started. Subsequently, when the spontaneous corrosion potential reaches a steady state, the cathode polarization characteristic and then the anodic polarization characteristic are sequentially measured.

Therefore, in order to obtain the desired corrosion rate from the measured polarization characteristics, the Tafel line extrapolation method for obtaining the corrosion rate from the polarization characteristics in a relatively wide potential range and the polarization at the time of minute polarization are used. The corrosion current density i _corr may be calculated by the polarization resistance method that determines the corrosion rate from the characteristics.

[0009]

In the case of this type of corrosion measuring apparatus, the Luggin tube 13 for the sample electrode 112 is used.
1 shows the facing relationship of the capillary-shaped tip portions 131a, specifically, the relationship between the facing distance (the distance in the front-rear X direction) and the facing position (each position in the left-right Y direction and the vertical Z direction) enables accurate corrosion measurement. Although it is extremely important for performing the measurement, in the conventional corrosion measuring device having the above-mentioned configuration, the sample electrode 11
Since the facing position of the capillary-shaped tip portion 131a with respect to 2 is fixed in a fixed manner and the facing position corresponding to each different sample electrode cannot be adjusted, its corrosion measurement is not always performed accurately and effectively. It had the inconvenience of not getting it.

On the other hand, the manner of holding the sample electrode 112 with respect to the sample electrode holder 111 is not specified,
There is also a problem that a poor connection is likely to occur between the sample electrode 112 and the electrode terminal.

The present invention has been made in view of such conventional circumstances,
The present invention has been made in order to solve these problems, and an object thereof is to provide a metal material corrosion measuring device capable of stably and accurately measuring metal material corrosion.

[0012]

In order to achieve the above-mentioned object, the invention according to claim 1 of the present invention is a sample solution having a corrosive action, and a sample electrode and a platinum electrode comprising a metal sample to be measured. In a corrosion measuring device of a metal material, which comprises at least a counter electrode consisting of and a Luggin tube with a capillary-shaped tip facing the sample electrode, the facing position of the capillary-shaped tip of the Luggin tube with respect to the sample electrode Two-dimensional direction of X, Y and / or X, Y,
It is a corrosion measuring device for metallic materials, characterized in that it can be adjusted in the three-dimensional direction of Z.

In the corrosion measuring device of the present invention, the facing position of the capillary-shaped tip of the Luggin tube with respect to the sample electrode can be adjusted in the two-dimensional directions of X and Y and / or the three-dimensional direction of X, Y and Z. Therefore, the facing position of the capillary-shaped tip end portion corresponding to each individual sample electrode can be easily and accurately set.

According to a second aspect of the present invention, in the corrosion measuring device for metallic materials according to the first aspect,
The metal sample as the sample electrode is connected to an electrode terminal via a pressing spring.

In the corrosion measuring device according to the first aspect, the connection to the sample electrode can be surely made.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an example of an embodiment of a metal material corrosion measuring apparatus according to the present invention will be described in detail with reference to FIGS.

FIGS. 1 (a) and 1 (b) are an overall front view (FIG. 1 (a)) and a schematic diagram showing a schematic outline of a corrosion measuring apparatus to which the present embodiment is applied. It is a partial top view (the same figure (b)). 2 is an enlarged vertical sectional view showing the relationship between the holding state of the sample electrode in the sample electrode holder and the arrangement position of the capillary-shaped tip of the Luggin tube with respect to the sample electrode, and FIG. It is a perspective view which decomposes | disassembles and shows the detailed structure of a sample electrode holder.

In these apparatus configurations shown in FIGS. 1 (a), 1 (b) to 3, the corrosion measuring apparatus according to the present embodiment has a corrosion-resistant electrolysis apparatus having a lid member 12 for containing a sample solution 14 therein. A bath 11; a sample electrode holder 21 holding a sample electrode 22 made of a metal sample piece to be measured; a counter electrode holder 31 holding a counter electrode 32 made of a platinum electrode;
Each has a Luggin tube holder 41 for holding the Luggin tube 42 in the vertical Z direction as described later, and further,
An intermediate tank 51 for accommodating the KCl solution 53 therein and a reference electrode 61 are provided in combination with the electrolytic tank 11.

The electrolytic cell 11 is a substantially wide-mouthed glass bottle in which the inner diameter is fully opened to facilitate the handling operation, and the outer periphery of the upper portion is provided with a fastening collar portion 11a. The upper opening has a tightening collar 11a.
The lid member 12 is covered by including the above, and the lid member 12 is closed by the tightening tool 13 so that the lid member 12 can be sealed at a plurality of locations. In addition, the sample electrode holder 21 and the counter electrode holder 31 are detachably attached to the lid member 12, and the Luggin tube holder 41 is similarly penetrated to the sample electrode holder 21. On the other hand, as will be described later, it is attached so that the position can be adjusted in the two-dimensional directions of X and Y. Separately, as in the conventional case, a gas inlet 71 and a gas discharge beak 72 for deoxidizing gas are provided. A thermometer 81 is arranged.

As shown in FIGS. 2 and 3, the sample electrode holder 21 has a holder main body 23 having a holding member 24 fixed to the lower side thereof, and the holder main body 23 is provided at a required position. A flange substrate 25 is provided on a predetermined portion of the lid member 12 so as to be detachably attached with an attachment screw 26. Here, with respect to the holding member 24, a spring 27a for obtaining a contact pressure, a contact pin 27 pressed by the spring 27a,
A cap screw ring 28 for holding the contact pin 27, a set of packings 22a for sealing the periphery of the sample electrode 22 on the front and back sides, and a mounting cap member 29 having a central opening 29a for holding and holding these are removable in sequence. And the spring 27a.
The electrode terminal 30 through the holder body 23 from the base side of the
I have taken out. Then, in the assembled state as described above, the sample electrode 22 is exposed in the central opening 29a of the mounting cap member 29 and is immersed in the sample solution 14, and in this case, the mounting cap is The sample electrode 22 for each measurement by the fitting / removing operation of the member 29.
Can be easily replaced.

As in the conventional case, the counter electrode holder 31 has a counter electrode chamber 34 divided into a lower portion of the holder body 33.
The counter electrode 32 is sealed and held therein and immersed in the sample solution 14, and the electrode terminal 36 is taken out through the holder body 33.
Also, with respect to the above, the flange substrate 35 provided at a required position is attached and fixed to a predetermined portion of the lid member 12.

The Luggin tube holder 41 has a holder body 43 for holding the Luggin tube 42 in a vertically (Z direction) position adjustable by a holding screw 45 for adjusting a holding position.
The holder main body 43 has the lid member 1
A flange base plate 44 is provided on a predetermined portion of No. 2 for mounting and fixing with a mounting screw 45. Here, in the flange substrate 44, the sample electrode holder 2 can be prepared by considering the shape, size, etc. of the mounting hole formed by the fixing screw 45.
The position can be adjusted in the front-rear direction (X direction) and the left-right direction (Y direction) with respect to the mounting position of 1.

A connecting pipe 47, such as a Teflon pipe, which is flexible and forms a liquid bridge, is taken out of the Luggin pipe 42 through a joint member 46. In this case, since the connecting pipe 47 uses a flexible member such as a Teflon pipe as compared to the conventional connecting pipe equivalent member which is a non-flexible glass pipe, the connecting pipe 47 is corroded. The handling operability during measurement is significantly improved.

Then, the position adjustment in the X and Y directions of the Luggin tube holder 41 and the position adjustment in the Z direction hold the sample electrode 22 on the exposed surface of the sample electrode holder 21. The facing interval and the facing position of the capillary-shaped tip portions 42a of the Luggin tubes 42 held by the Luggin tube holder 41 can always be set accurately.

Therefore, even in the corrosion measuring device having the configuration of the above embodiment, the corrosion of the metallic material can be measured in exactly the same manner as in the conventional case.

Using the corrosion measuring device of the present embodiment,
Here, 2 of SUS304 based on JIS G057
The results of measuring the anodic polarization curves in 0 wt% and 5 wt% sulfuric acid solutions are shown in the graphs of FIGS. 4 and 5. In the case of the conventional device, the measurement time is 3 hr, and a proper skill is required for the measurement operation. However, in the device of the present invention, in any of the cases of 20 wt% and 5 wt%, the measurement time of 1 hr was measured according to JIS. It was confirmed that the results can be easily and easily reproduced.

[0027]

As described above in detail with reference to the embodiments, according to the device of the present invention, a sample solution which exhibits a corrosive action,
A counter electrode composed of a sample electrode and a platinum electrode composed of a metal sample to be measured, and a metal material corrosion measuring device comprising at least a Luggin tube having a capillary tip facing the sample electrode. Since the facing position of the capillary-shaped tip of the can be adjusted in the two-dimensional directions of X and Y and / or the three-dimensional direction of X, Y, and Z, it is possible to correspond to each sample electrode to be measured. The facing position of the capillary-shaped tip portion with respect to each of the sample electrodes can be set accurately, and as a result, good and effective corrosion measurement can be extremely easily performed, which is a practically excellent feature.

[Brief description of drawings]

FIG. 1 is an overall front view (FIG. 1A) and a plan view of a main part (FIG. )).

FIG. 2 is an enlarged vertical cross-sectional view showing the relationship between the holding state of the sample electrode in the sample electrode holder of the same apparatus and the arrangement position of the capillary-shaped tip of the Luggin tube with respect to the sample electrode.

FIG. 3 is an exploded perspective view showing a detailed structure of the sample electrode holder of the above.

FIG. 4 is a graph showing a result of measuring an anode polarization curve in a 20 wt% sulfuric acid solution of SUS304 using the corrosion measuring apparatus according to the embodiment.

FIG. 5 is a graph showing a result of measuring an anode polarization curve in a 5 wt% sulfuric acid solution of SUS304 using the corrosion measuring device according to the embodiment.

FIG. 6 is a structural explanatory view (FIG. 1A) and an external perspective view (FIG. 2B) schematically showing an outline of a corrosion measuring device for a metal material that employs an electrochemical test method according to a conventional example. is there.

FIG. 7 is a block diagram illustrating an outline of a case where polarization characteristics are measured by a potentiostatic method using the above corrosion measuring apparatus.

[Explanation of symbols]

 11 Electrolyzer 11a Tightening collar 12 Lid member 13 Tightening tool 14 Sample solution 21 Sample electrode holder 22 Sample electrode 22a Packing 23 Holder body 24 Holding member 25 Flange substrate 26 Mounting screw 27 Contact pin 27a Spring 28 Holding screw ring 29 Cap member 29a Center opening 30 Electrode terminal 31 Counter electrode holder 32 Counter electrode 33 Holder body 34 Counter electrode chamber 35 Flange substrate 36 Electrode terminal 41 Lugin tube holder 42 Lugin tube 42a Capillary tip of Rugin tube 43 Holder body 44 Z-positioning presser screw 45 Flange substrate 46 Mounting screw for position adjustment in the X and Y directions 47 Joint member 48 Flexible connection pipe forming a liquid bridge 51 Intermediate tank 52 Plug member 53 KCl solution 61 Reference electrode 71 Gas inlet beak 72 Gas discharge 81 thermometer

Claims (2)

[Claims] 1. A structure comprising at least a sample solution capable of corrosive action, a counter electrode composed of a sample electrode made of a metal sample to be measured and a platinum electrode, and a Luggin tube having a capillary tip facing the sample electrode. In the corrosion measuring apparatus for metallic materials, the position of the capillary-shaped tip of the Luggin tube facing the sample electrode can be adjusted in the two-dimensional directions of X and Y and / or the three-dimensional direction of X, Y and Z. Corrosion measuring device for metallic materials. 2. The metal material corrosion measuring apparatus according to claim 1, wherein the metal sample as the sample electrode is connected to an electrode terminal via a pressing spring.