JPH08271676A - Formation method for metallographic testpiece of metal pipe sample element - Google Patents

Abstract

PURPOSE: To prevent removal of oxide film on a metallographic sample during polishing metallographic observation surface by preventing the generation of undesired gap between the metallographic sample and hardened resin part when the metallographic sample on which surface tantalum foil is contacted with aluminum foil, is embedded in a thermally hardening resin and a metallographic testpiece is formed. CONSTITUTION: Around a metallographic sample 13 split from a metal pipe sample element having formed an oxide film 11a, tantalum foil 14 hardly distorted is wound around the surface except the end edge surface 13a. A metallographic sample cover 16 obtained by covering with easily distorted aluminum foil is embedded in the resin such as bakelite and the like by the known press method and a fluid resin method to obtain a metallographic testpiece 17.

Description

Detailed Description of the Invention

[0001]

[Field of Industrial Application] As is well known, regarding fuel cladding tubes, etc., which compose PWR fuel assemblies, etc. After performing a corrosion test on a metal tubular sample such as a fuel cladding tube, an inspection such as measuring the thickness of an oxide film formed on the metal tubular sample by a metal phase test will be performed. The present invention, in such metal phase test, by embedding various metal tubular samples in the resin,
The present invention relates to a method for forming a metal phase test body that can be easily inspected.

[0002]

2. Description of the Related Art As is known, in order to measure the thickness of an oxide film formed on a metal tubular sample by the fuel cladding tube or the like, a metal phase test cannot be performed as it is. Or, by a liquid resin method, by embedding in a predetermined resin, so as to form a metal phase test body that can be subjected to a metal phase test, the metal phase test body,
The thickness of the oxide film is measured by polishing the edge surface side of the metal tubular sample, and then performing etching if necessary and observing the polished surface with a metallographic microscope.

Therefore, in the pressing method using the above-mentioned conventional press machine for forming the metal phase test body, as shown in FIG. 3, first, the metal tubular sample 1 is erected on the piston 2b in the cylinder 2a of the press machine 2. After mounting, the powder resin 3 made of bakelite, diallyl starrate, plastic or the like is charged through the upper opening 2c.

Next, after the upper opening 2c is closed with the closing lid 2d, the heater 2e is energized to heat it to about 100 to 200 ° C., and the piston 2b is pushed up to perform the press working. The gold phase test body 4 is formed. In the same figure, 4a is an outer cured resin portion formed on the outer periphery of the metal tubular sample 1, and 4b is the metal tubular sample 1
The inside cured resin portions formed inside are shown respectively.

However, in the case of the pressing method, the powder resin 3 is heated by the heater 2e to melt, and when the powder resin 3 is cooled and solidified, thermal contraction occurs, and the thermal contraction force is caused by the metal phase test body 4. Since the metal tube-shaped sample 1 is oriented toward the axis, the outer peripheral surface 1a of the metal tubular sample 1 and the outer hardened resin portion 4a form an oxide film O.
Although it is solidified in a close contact state through the
As a result of b also shrinking toward the axial center and solidifying, as shown in FIG. 5, an undesired gap g occurs between the inner peripheral surface 1b of the metal tubular sample 1 and the inner hardened resin portion 4b.

Further, in the liquid resin method described above, as shown in FIG. 4, the metal tubular sample 1 mounted upright on the base 5 and the ring mounted upright on the base 5 as well. It is surrounded by a body 6, and a liquid resin 7 such as polyester or epoxy flows into the ring body 6. Since the liquid resin 7 contains a curing agent, the liquid resin 7 is solidified by releasing heat of less than 100 ° C. when left standing. Therefore, even when the liquid resin method is used, the liquid resin 7 is solidified with heat shrinkage, and when the metal phase test body 4 as shown in FIG. The cured resin portion 4a is the outer peripheral surface 1a of the metal tubular sample 1.
However, a gap g is generated between the inner peripheral surface 1b and the inner hardened resin portion 4b.

As described above, according to the conventional method for forming the metallic phase test body 4, a gap is formed between the inner peripheral surface 1b of the metal tubular sample 1 and the inner hardened resin portion 4b by any of the above means. g is generated, which causes the above-mentioned metal phase test body 4
Edge surface 1c exposed in the metal tubular sample 1 in
(See FIG. 6) During the etching treatment of the observation surface of the metal phase, the applied etching liquid remains in the gap g, and as a result, as shown in FIG. 6 (A),
The etching solution is leached in the etching process, and the contamination portion 1d is unavoidably generated.

Further, due to the generation of the gap g, as shown in FIG. 6 (B), the upper surface 4c of the metallic phase test body 4 is formed.
By polishing the end surface 1c of the metal tubular sample 1 by polishing, a so-called surface sag 1e is generated, and further, the oxide film o formed on the metal tubular sample 1 is caught on the polishing paper surface. However, this causes a problem such as damage such as peeling from the inner peripheral surface 1b of the metal tubular sample 1.

If the above-mentioned gap g is formed,
Abrasive debris will invade into this, and when trying to polish using abrasive paper with a fine particle size in the next step, the invading abrasive debris will advance from the gap and the abrasive debris with a large particle size. As a result, there is a risk of scratching the polished surface of the edge of the metallurgical test object.

Therefore, in order to solve the above-mentioned problems, a different metal is already wound around the outer periphery of the metal tubular sample, or a plating means or a coating means is applied to form the outer peripheral surface of the metal tubular sample. It is also considered that the oxide film is covered with a different kind of metal layer to prevent a defect such as damage due to polishing of the oxide film.

However, it is extremely difficult to wind the dissimilar metal around the peripheral surface of the tubular sample so as to be in close contact with the mere winding means as described above, and not only the workability is poor, but also at this time. Even if the metal phase sample has a shape that can be easily wound, it is difficult to wind the metal phase sample so that the sample is closely adhered to the oxide film.

Further, when the plating or coating means is used as described above, if the sample to be tested is a non-conductive material such as ceramics, the means cannot be adopted.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional drawbacks. For a test sample such as a fuel cladding tube, a conventional pressing method or a liquid resin method is applied to the sample to be inspected. Embedding in a predetermined resin, when forming a metal phase test body for use in the metal phase test, a test sample surface,
In order to prevent unintended gaps from being formed between the cured resin part and the embedded resin part, first the metallic phase sample material is not split as it is, but the metal phase sample is formed in a vertically split state,
Prior to embedding this gold phase sample in the cured resin part,
Appropriate coating treatment is also applied to the gold phase sample to prevent the generation of voids, thereby making it possible to sufficiently and easily observe the oxide film in the gold phase sample with a metallurgical microscope. That is the purpose.

[0014]

In order to achieve the above object, the present invention obtains a test sample by forming an oxide film on the surface of a metal tubular sample material, and polishes the edge of the test sample. By observing with a metallurgical microscope, to perform a metal phase test of a test sample for measuring the thickness of the oxide film, a metal phase test body is prepared by a resin embedding process of the test sample by a press method or a liquid resin method. In the method of forming, prior to the resin embedding step, the test sample is obtained as a longitudinal split in the axial direction of the metal tubular sample material to obtain a metallic phase sample, and the edge surface of the metallic phase sample is Except for this, a metal phase sample encapsulation formed by wrapping tantalum foil on the other peripheral surface, and further wrapping the entire surface of this tantalum foil or the entire surface of the metal phase sample including this with aluminum foil is used. Tubular sample characterized in that Trying to provide for metallographic specimens forming method of wood.

[0015]

According to this method for forming a test object for a metal phase, the test sample embedded in the resin by the pressing method or the liquid resin method is not a mere metallic tubular sample material itself, but is divided vertically into metal phases. Since the sample was obtained and the gold phase sample was embedded in the resin, the formation of the gap due to the shrinkage of the resin is suppressed as compared with the case where the metal tubular sample material is embedded in the resin as it is.

Further, according to the present invention, the tantalum foil which is not easily deformed is first wrapped around the peripheral surface of the above-mentioned gold phase sample, and then the easily deformable aluminum foil is covered from the outside. , The tantalum foil can be wrapped around the surface of the sample in a sufficiently tightly adhered state, and this can be held.Therefore, there is an unwillingness between the cured resin part of the metal phase test body and the metal phase sample. Even if the gold phase sample is polished without forming a gap, the oxide film can be prevented from being damaged or so-called sagging can be prevented from occurring, and the etching solution can be leached from the gap. Therefore, it is possible to prevent the gold phase sample from being soiled.

[0017]

EXAMPLES The present invention will be described below with reference to FIGS. 1 and 2. The tubular sample material 11 in FIG. 1 has an outer diameter of about 10 mm and an axial length of about 10 mm. As described above, a zirconium alloy is used, and an oxide film 11a is formed on the outer surface of the tubular sample material 11 by, for example, a cutting line 1 passing through the central axis point thereof.
By longitudinally cutting at 2, etc., a longitudinally-divided metal phase sample 13 cut in the longitudinal direction by half division or the like is obtained.

Next, a tantalum foil 14 is first formed on the other surfaces of the vertically divided metal phase sample 13 except for the both end edge surfaces 13a in the axial direction (the metal phase observation surface which is polished and subjected to the metal phase test). Wrap as in (b). As this tantalum foil 14, a commercially available product having a thickness of 0.1 to 0.2 mm can be used, and a tape-shaped one whose width length is equal to the height which is the longitudinal direction of the metallic phase sample 13 is used. Then, it is wound around the outer peripheral surface of the surface of the metal phase sample 13, and such work can be easily performed unlike the case of the tubular body.

Here, in the embodiment shown in FIG. 1B, after the metal phase sample 13 is wound once, its side edge portions 14a are slightly overlapped with each other. It is also permissible to bring the side edge portions 14a into a butted state or to make the number of windings plural.

Next, in the present invention, a commercially available aluminum foil 15 is provided on the entire surface of the tantalum foil 14 wound around the outer peripheral surface of the metallic phase sample 13 or the entire surface of the metallic phase sample 13 as shown in FIG. 1 (c). By applying the aluminum foil 15 by utilizing the property of the aluminum foil which is easily plastically deformed, the tantalum foil 14 which is hard to contact the gold phase sample 13 is attached to the metal phase sample 13 as described above. Since the aluminum foil 15 is sufficiently pressed so as to be pressed and held so as to be in a close contact state, the metal phase sample enclosure 16 is formed as shown in FIG. 1 (c).

The thus obtained gold phase sample enclosure 16 is
By using the conventional pressing method illustrated by FIG. 3,
For example, by embedding in Bakelite resin material and performing press molding by thermosetting as known using a press machine,
A metal phase test body 17 having a bottom end face as shown in FIG. 2 and having a cylindrical shape with a diameter of about 30 mm and a height of about 20 mm is obtained.

The metal phase test body 17 thus obtained is composed of a cured resin portion 17a made of Bakelite or the like and a metal phase sample 13 embedded in the resin portion 17a.
7b is polished by a conventional method and, if necessary, is etched to obtain a polished edge surface 13a of the gold phase sample 13.
Then, a metal phase observation surface is formed, and a metal phase test is conducted on the thickness and physical properties of the oxide film 11a in the metal phase sample 13 described above using a well-known metal microscope and a scanning electron microscope.

As described above, according to the present embodiment, as the metallic phase sample 13, the metallic tubular sample material 11 is not used as it is, but the vertically divided metallic phase sample 13 is embedded in the resin. Therefore, a large gap as described with reference to FIG. 3 is not formed due to heat shrinkage during resin processing.

Moreover, the tantalum foil 14 is further wrapped around the entire peripheral surface of the metal phase sample 13 except the end edge surface 13a, and the tantalum foil 14 is pressed and covered with the aluminum foil 15. Therefore, the tantalum foil 14 comes into close contact with the peripheral surface of the metallic phase sample 13, and this state is maintained by the characteristics of the aluminum foil 15. As a result, the metallic phase sample 1
3 and the tantalum foil 14 are closely held without a gap. Then, when the gap was measured for the metallic phase test body 17 obtained by the method of the present invention, the gap g ₁ between the metallic phase sample 13 and the tantalum foil 14 on the outer peripheral side in FIG. 2 was measured.
Was zero, and it was confirmed that the gap g ₂ between the metal phase sample 13 and the tantalum foil 14 on the inner peripheral side was 0.1 μm or less.

The reason why the gaps g ₁ and g ₂ can be made is that the tantalum foil 14 is not easily deformed and therefore has no wrinkle, so that it is likely to come into close contact with the gold phase sample 13. Since the tantalum foil 14 can be pressed by the aluminum foil 15 which is easily deformed, the close contact state of the tantalum foil 14 with the metal phase sample 13 can be prevented by the aluminum foil 15
Will be held. Moreover, aluminum foil 1
Since No. 5 has a softness that the tantalum foil 14 does not have, it plays a role of a kind of cushioning material in the metallic phase test body 17, which further suppresses the generation of gaps. Of.

For this reason, even if the metal-phase test body 17 is subjected to the polishing treatment as described above, the above-mentioned surface sag and damage peeling of the oxide film 11a may occur on the polished surface of the metal-phase sample 13. Therefore, the metal-microscope observation of the polished surface of the metallic phase can be performed without any trouble.

Further, as described above, since the gap is substantially not generated, the etching treatment liquid is prevented from leaching to the gold phase observation surface of the gold phase sample, and the undesired stain is caused. Never happened.

As will be described in more detail in this example, the end face 13a of the metallic phase sample 13 was not covered with tantalum foil, but was covered with the aluminum foil 15 as described above. Even if there is, since the aluminum foil of the edge surface 13a is peeled off by a slight polishing process on the metal phase test body,
The polishing can be easily completed. Aluminum foil 1
With respect to No. 5, it is easier to press the tantalum foil 14 against the metal phase sample 13 more easily with the entire covering.
It is also possible to cover only four, which makes the polishing process easier.

[0029]

Since the present invention can be carried out as described above, a vertically split metal phase sample is used, and a tantalum foil and an aluminum foil having different characteristics are doubly applied thereto. Then, by embedding this in a resin, a metal phase test body is obtained, which makes it possible to make the gap between the cured resin portion and the metal phase sample close to zero. . Therefore, when performing a gold phase test on an oxide film of a gold phase sample, the polishing process may damage the oxide film, cause surface sag on the observation surface of the gold phase, or even cause the etching solution to leak out from the gap. It is possible to eliminate the drawbacks of (1) and (2) above, which makes it possible to carry out a gold phase test such as measurement of an oxide film of a gold phase sample easily and with high reliability without any trouble.

[Brief description of drawings]

1 shows a surface material used for carrying out a method according to the present invention, (a) is a perspective view in which a part of a tubular sample material is cut away, and (b) is a vertically split metal phase sample and tantalum foil. FIG. 3 is a perspective view showing a state in which the aluminum foil is covered, and FIG. 6C is a perspective view showing a state in which an aluminum foil is overlaid on the one in FIG.

FIG. 2 is a plan view of a metallic phase test body molded by the method of the present invention.

FIG. 3 is a process explanatory view showing a pressing method which is a method for forming a metal phase test body of a tubular sample in a conventional example.

FIG. 4 is a process explanatory view showing a conventional method for forming a metal phase test body by a fluid resin method different from the pressing method shown in FIG.

FIG. 5 is an enlarged cross-sectional view of a main part of a metallic phase test body obtained by a conventional method.

FIG. 6 (A) is an enlarged plan explanatory view of an essential part showing an etching solution leached state of the same metal phase test body, and FIG. 6 (B) is a vertical sectional front explanatory view showing the same top surface drooping state.

[Explanation of symbols]

 11 Metal Tubular Sample Material 11a Oxide Film 13 Gold Phase Sample 13a Edge Surface 14 Tantalum Foil 15 Aluminum Foil 16 Gold Phase Sample Encapsulation

Claims (1)

[Claims] 1. A measurement sample is obtained by forming an oxide film on the surface of a metal tubular sample material, and the edge polished surface of the test sample is observed with a metallurgical microscope to measure the thickness of the oxide film. In order to perform a metal phase test of the test sample to be formed, in the method of forming a metal phase test body by a resin embedding step of this test sample by a pressing method or a liquid resin method, prior to the resin embedding step, After the test sample was obtained as a longitudinal split in the axial direction of the metal tubular sample material, a metal phase sample was obtained, and then a tantalum foil was wound around the peripheral surface other than the end edge surface of the metal phase sample, and this tantalum was further wrapped. The metallic phase of the metallic tubular sample material is characterized in that the entire surface of the foil or the entire surface of the metallic phase sample including the metallic foil is covered with an aluminum foil. Method for forming test body.