JP2000088789A - Corrosion test stand and corrosion test apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To evaluate corrosion resistances of many materials electrochemically by one electrode and install an apparatus compactly in a small space inside an actual plant or the like. SOLUTION: A corrosion test stand 1 is constituted which includes a counter electrode 7, a reference electrode 8 having a plurality of salt bridge Luggin tubes 9 in the periphery and a specimen holder 6 for holding the reference electrode 8 and specimens 10 arranged in the vicinity of leading end parts of the plurality of salt bridge Luggin tubes 9. The corrosion test apparatus comprises the corrosion test stand 1, a potentiostat and a switch box with a timer for sequentially switching and electrically connecting lead wires 4a of the specimens 10 to the potentiostat.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used to select, by electrochemical evaluation, metal materials of various devices used in various water environments, particularly, water treatment facilities such as water and sewage treatment facilities and pulp bleaching facilities. , A corrosion test stand, and a corrosion test apparatus using the same.

[0002]

2. Description of the Related Art As a conventional on-site type corrosion resistance evaluation apparatus,
There is a method for monitoring the corrosion state of structural materials of an actual plant (Japanese Patent Application Laid-Open Nos. Hei 6-3314 and Hei 8-271404). These monitors are
In order to monitor the corrosion status of the materials used in the actual plant or the corrosiveness of the actual plant environment, install a probe or electrode in the measuring section and use an electrochemical meter such as a corrosion meter, potentiostat or galvanostat .

In order to simultaneously evaluate a plurality of types of materials for the purpose of selecting a material suitable for the corrosive environment of an actual plant, for example, in the method disclosed in Japanese Patent Application Laid-Open No. In addition, it is necessary to provide a probe or an electrode for each measuring unit as described in Japanese Patent Application Laid-Open No. 8-271404, and a large number of electrodes and a large space are required.

[0004] Further, when carrying out, for example, environmental water of an actual plant to a laboratory, and evaluating the corrosion resistance of various metallic materials, the water quality at the site changes during transportation, and accurate evaluation cannot be performed. Further, the quality of water containing corrosive factors, such as dissolved chlorine, bicarbonate ions, and ozone, whose concentration changes due to decomposition and the like, is constantly changing in the field.

[0005]

Therefore, when performing quantitative comparative evaluation of the corrosion resistance of various metal materials, comparative evaluation of the corrosion resistance of each material is performed electrochemically in a local environment such as an actual plant. However, as described above, a structure for mounting a large number of electrodes or probes and a test piece corresponding to each of these electrodes or probes (hereinafter, this structure is referred to as a corrosion test stand) is required, and a large space is required. In some cases, there is a problem that it is not possible to compare and evaluate the corrosion resistance of many types of metal materials.

The present invention solves the above-mentioned problems. One electrode can electrochemically evaluate the corrosion resistance of a large number of materials, and is small and can be used in a small space in an actual plant or the like. It is an object of the present invention to provide a corrosion test stand that can be installed and a corrosion test apparatus using the same.

[0007]

A first corrosion test stand according to the present invention comprises a counter electrode, a reference electrode having a plurality of salt bridge lugine tubes around it, a reference electrode holding the reference electrode and a plurality of salt electrodes. It has a test piece holder which can arrange and hold a test piece near each tip of the bridge lugine tube.

[0008] A second corrosion test stand according to the present invention comprises:
In the first corrosion test stand, a plurality of salt bridge lugine pipes are radially arranged so that a distance between the reference electrode and the test piece is equal to the reference electrode.

A third corrosion test stand according to the present invention comprises:
In the first or second corrosion test stand, the counter electrode has a cylindrical shape surrounding the reference electrode.

A fourth corrosion test stand according to the present invention comprises:
In the above-mentioned first corrosion test stand, a high water-absorbing polymer in which an electrolytic solution is absorbed as an electrically conductive gel is provided in a lugine tube.

A fifth corrosion test stand according to the present invention comprises:
In the first corrosion test stand, a porous ceramic cap is attached to the tip of the lugine tube.

A first corrosion test apparatus according to the present invention comprises a counter electrode, a reference electrode having a plurality of salt bridge lugine pipes around the counter electrode, and a tip end of the plurality of salt bridge lugine pipes while holding the reference electrode. Corrosion test stand having a test piece holder capable of placing and holding a test piece in the vicinity of each, an electrochemical measuring instrument, and for sequentially switching electrical connection between the electrochemical measuring instrument and the plurality of test pieces With a switch box with a timer.

In a second corrosion test apparatus according to the present invention, in the first corrosion test apparatus, the test piece holder is at least a part of a closed container, and is led out as a conduit for introducing a fluid into the container. And a conduit.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is an exploded view of a corrosion test stand constituting a corrosion test apparatus according to an embodiment of the present invention, and FIG. 2 is an assembled sectional view of the corrosion test stand. In the figure, 1 is a corrosion test stand, 6 is a test piece holder formed of an insulating material, 7 is a counter electrode made of a platinum net, 8 is a reference electrode with a multi-branched lugine tube 9, and a multi-branched lugine tube 9 is a salt bridge. It is electrically connected to the electrode 8. Reference numeral 10 denotes a test piece. The test piece holder 6 is formed so that the test pieces 10 can be set near the tips of the plurality of lugine tubes 9 and that the reference electrodes 8 are held. 4a is a lead electrically connected to the test piece 10, and 4b is a lead of the counter electrode 7 and the reference electrode 8.

As described above, a plurality of lugine tubes 9 are attached to the reference electrode 8 and a corrosion test stand is formed so that a test piece 10 can be set near each of the tips of the plurality of lugine tubes 9. Thus, a small corrosion test stand capable of evaluating the corrosion resistance of a plurality of types of test pieces with a reference electrode is obtained.

A plurality of salt bridge lugine tubes 9 are projected radially from the reference electrode 8 so that the distance between the reference electrode 8 and each test piece 10 becomes equal with the reference electrode 8 as a center. Thus, the electric resistance of each salt bridge lugine tube 9 can be made the same, and the measurement accuracy is improved.

Usually, a mixture of agar and an electrolyte is used for the salt bridge in the lugine tube 9, but a superabsorbent polymer such as starch / polyacrylate (Sunfresh ST-100) is used. : Sanyo Chemical Industry Co., Ltd.)
By infiltrating and gelling an electrolytic solution such as a 1 mol / l aqueous solution of potassium chloride, it is possible to eliminate the generation of mold or bacteria and to prevent contamination of the measurement environment.

Further, by providing a cap 11 of a porous ceramic (# 5 glass filter) at the tip of the lugine tube 9, the electrolyte contained in the salt bridge of the lugine tube 9 can be prevented from leaking to the outside. The distance between the cap 11 attached to the tip of the lugine tube 9 and the test piece 10 was about 5 mm,
When the entire corrosion test stand 1 shakes, the test piece 10
And the cap 11 can be prevented from contacting each other.

In this embodiment, the test piece holder 6 has a hexagonal shape and a cylindrical shape. However, the test piece holder 6 has a cylindrical shape, a cutout provided in a part of the cylindrical shape, and a cylindrical shape. Various shapes can be adopted depending on the situation of the installation location of the corrosion test stand, such as holding the test piece at the bottom, the top, or both the bottom and the top.

Embodiment 2 FIG. 3 is a schematic diagram of a measurement system for comparing the corrosion resistance of various metal materials in an ozone injection treatment tank using the corrosion test stand 1. In the figure, 5
Is a switch box with a timer, 2 is a potentiostat, 3 is a recording device for recording the measured value of the potentiostat, and the lead wire 4a of the test piece 10 is connected to the potentiostat 2 via the switch box 5 with the timer. 7 and the reference electrode 8 are the lead wires 4 respectively.
The test piece 10 to be measured is connected to the potentiostat 2 by a switch b and is sequentially switched by a switch box 5 with a timer.

As described above, the corrosion test stand is formed so as to have the reference electrode 8 with the multi-branched lugine tube 9 and to set the test pieces 10 near the tips of the plurality of lugine tubes 9, respectively. By sequentially switching the test pieces 10 to be measured by 5, a small corrosion test apparatus capable of electrochemically measuring a plurality of test pieces 10 with one reference electrode is obtained.

Using the corrosion test apparatus constructed as described above, for example, as shown in FIG. 4, the corrosion test stand 1 is suspended by a wire in an ozone injection treatment tank 12 containing ozone water, and ozone injection is performed. Each test piece 10 and the potentiostat 2 were immersed in a water treatment tank every minute with a switch box 5.
The change with time of the corrosion potential of each test piece 10 is measured while switching the connection with the test piece 10 and input to the recording device 3. FIG. 5 is a graph obtained by extracting data measured in the ozone injection treatment tank 12. This result was measured while switching the connection between each test piece 10 and the potentiostat 2 with the switch box 5. The timer of the switch box 5 with a timer was turned off, and the corrosion current of each test piece 10 was measured. It is also possible.

In this embodiment, the corrosion test stand 1 is immersed in the ozone-injected water treatment tank, but various devices used in water treatment facilities such as water and sewage treatment facilities and pulp bleaching facilities. For example, if the corrosion test stand 1 can be directly immersed, it can be applied to various corrosive environments.

Embodiment 3 FIG. In the present embodiment, a corrosion test stand can be attached in the middle of a pipe so that the corrosiveness of cooling water or the like flowing through the pipe can be evaluated.

FIG. 6 shows a corrosion test stand used in the corrosion test apparatus according to the present embodiment. Reference numeral 19 denotes a corrosion test stand which closes up and down the test piece holder 6 to which the test piece 10 is fixed. A pipe 16 provided with a bottom plate 14 and an upper plate 15 is fixed with bolts 17 to form a sealed structure. A counter electrode 7 and a reference electrode 8 with a multi-branched Lugine tube 9 are supported on a top plate 15 by a support rod 18 fixed to a bottom plate 14, and a lead wire 4 of each of the counter electrode 7 and the reference electrode 8 is provided.
Are configured to penetrate the upper plate 15 by a seal structure and to be connected to a potentiostat (not shown). Further, conduits 16a and 16b with flanges are provided above and below the pipe 16 so as to be connected to the pipe.

The conduits 16a and 16b with flanges of the corrosion test stand 19 shown in FIG. 6 are connected by a seal structure such as packing between pipes to be evaluated for corrosion, and the lead wire 4a of the test piece 10 is a timer. Example 1 was connected to the potentiostat 2 via a switch box 5 with a counter, and the counter electrode 7 and the reference electrode 8 were connected to the potentiostat 2 by a lead wire 4, respectively. The change with time of the corrosion potential of each test piece 10 was measured and input to the recording device 3 in the same manner as described above.

In this embodiment, the case where the shape of the test piece holder 6 is hexagonal and cylindrical is shown. However, various shapes such as a cylindrical shape can be adopted according to the situation of the installation location. In addition, the flanged conduits 16a and 16b are
4 and the upper plate 15.

[0028]

According to the first corrosion test stand according to the present invention, a counter electrode, a reference electrode having a plurality of salt bridge lugine tubes around the same, the plurality of salt bridge lugine holding the reference electrode, A small specimen that can electrochemically measure a plurality of test specimens with a single reference electrode by having a test specimen holder that can arrange and hold the test specimen near each end of the tube Is obtained.

According to the second corrosion test stand according to the present invention, a plurality of salt bridge lugine tubes are radially arranged around the reference electrode so that the distance between the reference electrode and the test piece is equal. Therefore, the electric resistance of each salt bridge lugine tube can be made the same, and the measurement accuracy is improved.

According to the third corrosion test stand according to the present invention, since the counter electrode is cylindrical in shape surrounding the reference electrode, the counter electrode can be common to each test piece, and a small space is effectively used. can do.

According to the fourth corrosion test stand according to the present invention, since the lugine tube has a highly water-absorbing polymer in which an electrolytic solution is absorbed as an electrically conductive gel,
The generation of mold or bacteria can be eliminated, and contamination of the measurement environment can be prevented.

According to the fifth corrosion test stand of the present invention, since the porous ceramic cap is attached to the tip of the lugine tube, the electrolyte in the salt bridge is prevented from leaking to the outside,
It is possible to prevent contamination of the measurement environment.

According to the first corrosion test apparatus of the present invention, a counter electrode, a reference electrode having a plurality of salt bridge lugine tubes around it, and a reference electrode holding the reference electrode and a plurality of salt bridge lugine tubes. Corrosion test stand having a test piece holder capable of placing and holding a test piece near each tip, an electrochemical measuring instrument, and an electrical connection between the electrochemical measuring instrument and the plurality of test pieces sequentially. Since a switch box with a timer for switching is provided, a small one that can electrochemically measure a plurality of test pieces with one reference electrode is obtained.

According to the second corrosion test apparatus of the present invention, the test piece holder is at least a part of the closed container, and the container is provided with a conduit for introducing a fluid and a conduit for discharging the fluid. Therefore, a corrosion test in a closed piping system or the like becomes possible.

[Brief description of the drawings]

FIG. 1 is an exploded view of a corrosion test stand according to an embodiment of the present invention.

FIG. 2 is an assembled sectional view of the corrosion test stand shown in FIG.

FIG. 3 is a schematic diagram showing a measurement system of the corrosion test apparatus according to the present invention.

FIG. 4 is a diagram showing a measurement example of a corrosion potential.

FIG. 5 is a sectional view of a corrosion test stand according to another embodiment of the present invention.

FIG. 6 is a sectional view showing a configuration of a corrosion test apparatus according to an embodiment of the present invention.

[Explanation of symbols]

1 Corrosion test stand, 2 potentiostat, 3
Recording device, 4, 4a, 4b lead wire, 5 switch box with timer, 6 specimen holder, 7 counter electrode, 8
Reference electrode, 9 Luggin tube, 10 test piece, 11 cap, 12 tightening nut, 13 packing, 14 bottom plate, 15 top plate, 16a and 16b conduit

Claims (7)

[Claims] 1. A reference electrode having a counter electrode, a plurality of salt bridge lugine tubes around the reference electrode, and holding the reference electrode and disposing and holding a test piece near each of the tips of the plurality of salt bridge lugine tubes. A corrosion test stand comprising a test piece holder adapted to be used. 2. The corrosion test according to claim 1, wherein a plurality of salt bridge lugine tubes are provided radially so that the distance between the reference electrode and the test piece is equal to the center of the reference electrode. stand. 3. The corrosion test stand according to claim 1, wherein the counter electrode has a cylindrical shape surrounding the reference electrode. 4. The corrosion test stand according to claim 1, wherein the lugine tube has a superabsorbent polymer in which an electrolytic solution is absorbed as an electrically conductive gel. 5. The corrosion test stand according to claim 1, wherein a cap made of a porous ceramic is attached to a tip of the lugine tube. 6. A reference electrode having a counter electrode, a plurality of salt bridge lugine tubes around the reference electrode, and holding the reference electrode, and disposing and holding a test piece near each of the tips of the plurality of salt bridge lugine tubes. Corrosion test stand having a test piece holder made possible, an electrochemical measuring instrument, and a switch box with a timer for sequentially switching electrical connection between the electrochemical measuring instrument and the plurality of test pieces. Characteristic corrosion test equipment. 7. The corrosion test apparatus according to claim 6, wherein the test piece holder is at least a part of a closed container, and a conduit for introducing a fluid and a conduit for discharging the fluid are provided in the container.