JP3005844B2 - Method for forming metal phase test body of metal tubular sample material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

2. Description of the Related Art As is well known, for fuel cladding tubes and the like constituting a PWR fuel assembly, etc., when this is adopted in a nuclear reactor, among various tests as to whether or not combustion without hindrance will be carried out, it is required. After a corrosion test is performed 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 gold phase test is performed. The present invention, in such a 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, to form a metal phase test body that can be subjected to a metal phase test, for 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, if necessary, etching it and observing the polished surface with a metal microscope.

[0003] In the pressing method using the conventional press machine for forming the above-mentioned metal phase test body, a metal tubular sample 1 is first erected on a piston 2b in a cylinder 2a of the press machine 2 as shown in FIG. It is placed, and a powder resin 3 made of bakelite, diallyl slate, plastic, or the like is charged through the upper opening 2c.

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

However, according to the above pressing method, the powder resin 3 is melted by heating by the heater 2e, and when the powder resin 3 is cooled and solidified, thermal contraction occurs. Since the outer peripheral surface 1a of the metal tubular sample 1 and the outer cured resin portion 4a are oriented toward the axis, the oxide film O
Hardens in the close contact state through the inner side, but the inside cured resin portion 4
As a result, b also shrinks toward the axis and solidifies. As a result, an undesired gap g is generated between the inner peripheral surface 1b of the metal tubular sample 1 and the inner cured resin portion 4b as shown in FIG.

In the liquid resin method described above, as shown in FIG. 4, a metal tubular sample 1 mounted on a base 5 and a ring mounted on the base 5 are also mounted. A liquid resin 7 such as polyester or epoxy flows into the ring body 6. Since a curing agent is mixed in the liquid resin 7, the liquid resin 7 emits heat of less than 100 ° C. and is solidified by leaving it unattended. Therefore, when the liquid resin method is used, when the liquid resin 7 solidifies with heat shrinkage and the metal phase test body 4 as shown in FIG. The cured resin portion 4a is provided on 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 cured resin portion 4b.

As described above, when the conventional method for forming the metal phase test body 4 is employed, the gap between the inner peripheral surface 1b of the metal tubular sample 1 and the inner hardened resin portion 4b can be obtained by any of the above means. g, which causes the metal phase test body 4
Edge surface 1c exposed in the metal tubular sample 1
At the time of etching the gold phase observation surface (see FIG. 6), the applied etchant penetrates and remains in the gap g. As a result, as shown in FIG.
The etching solution leaches out during the etching process, and the generation of the stained portion 1d due to the leaching is inevitable.

[0008] In addition, the generation of the gap g causes the upper surface 4c of the metal phase test body 4 as shown in FIG.
Is polished to polish the edge surface 1c of the metal tubular sample 1, so-called sagging 1e occurs, and furthermore, the oxide film o formed on the metal tubular sample 1 is caught on the polishing paper surface. However, there is a problem that this is damaged such as peeling off from the inner peripheral surface 1b of the metal tubular sample 1.

When the above-mentioned gap g is formed,
The polishing debris intrudes into this, and when trying to polish using a fine-grained abrasive paper in the next step, the penetrated polishing debris advances from the gap, and the polishing debris having a large particle size is removed. Accordingly, there is a possibility that the edge polishing surface of the metal phase test body may be damaged.

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

[0011] However, it is extremely difficult to wind a dissimilar metal around the peripheral surface of the tubular sample in such a manner as to be in close contact with the simple winding means as described above. Even if the gold phase sample has a shape that can be easily wound, it is difficult to wind the sample so as to be in close contact with the oxide film.

In the case of using plating or coating means as described above, if the sample to be tested is a non-conductive material such as ceramics, the use of such means becomes impossible.

[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, the test sample or the liquid resin method is used. Embedded in a predetermined resin, when forming a metal phase test body to be subjected to the metal phase test, the surface of the test sample,
In order to prevent undesired gaps from occurring between the cured resin portion embedding this, first, not the metal tubular sample material as it is, but forming a gold phase sample in a vertically divided state,
Prior to embedding this gold phase sample in the cured resin part,
The gold phase sample is also subjected to an appropriate coating treatment for preventing generation of gaps, so that the oxide film in the gold phase sample can be sufficiently and easily observed with a metallographic microscope. That is the purpose.

[0014]

According to the present invention, in order to achieve the above object, a test 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 obtained. Is observed with a metallurgical microscope, and a metal phase test is performed on the test sample to measure the thickness of the oxide film. In the forming method, prior to the resin embedding step, after the test sample obtains a gold phase sample as a vertical split which is an axial direction of the metal tubular sample material, the edge surface of the gold phase sample is A tantalum foil is wrapped around the other peripheral surface, and the entire surface of the tantalum foil or the entire surface of the gold phase sample including the tantalum foil is used. Metal tubular sample characterized in that it can be used Trying to provide for metallographic specimens forming method of wood.

[0015]

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

Further, in the present invention, a tantalum foil that is hard to deform is first wound around the peripheral surface of the above-mentioned gold phase sample, and then an aluminum foil that is easily deformed is covered from the outside. However, the tantalum foil can be wrapped around the peripheral surface of the sample in a sufficiently close contact state and can be held, so that there is no reluctance between the cured resin portion of the gold phase test body and the gold phase sample. Even if the metal phase sample is polished without gaps, the oxide film can be prevented from being damaged or so-called sagging can be prevented, and the etching solution can be leached from the gaps. Can prevent the gold phase sample from being stained.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to FIGS. 1 and 2. The tubular sample material 11 shown in FIG. 1 has an outer diameter of about 10 mm, an axial length of about 10 mm, and a fuel cladding tube or the like. An oxide film 11a is formed on the outer surface of the zirconium alloy by an oxidizing process, and the tubular sample material 11 is cut, for example, by a cutting line 1 passing through the center axis thereof.
By cutting vertically in 2 or the like, a vertically split gold phase sample 13 cut in the longitudinal direction by half-split or the like is obtained.

Next, a tantalum foil 14 is first placed on the other surface of the vertically divided gold phase sample 13 except for both end surfaces 13a in the axial direction (a metal phase observation surface to be polished and subjected to a gold phase test) as shown in FIG. Wrap as shown in (b). A commercial product having a thickness of 0.1 to 0.2 mm can be used for the tantalum foil 14, and a tape-like material having a width equal to the height of the gold phase sample 13 in the longitudinal direction is used. Then, it is wound around the outer peripheral surface of the surface of the gold phase sample 13, and such an operation can be easily performed unlike the case of the tubular body.

Here, in the embodiment shown in FIG. 1 (b), after winding once around the gold phase sample 13, the side edges 14a are slightly overlapped with each other. It is also permissible to make the side edge portions 14a abutted or to make the number of turns plural.

Next, in the present invention, a commercially available aluminum foil 15 is usually placed on the entire surface of the tantalum foil 14 or the entire surface of the gold phase sample 13 from above the tantalum foil 14 wound around the outer peripheral surface of the gold phase sample 13 as shown in FIG. By applying the aluminum foil 15 to the metal phase sample 13, the tantalum foil 14 that does not easily come into contact with the metal phase sample 13 is applied to the metal phase sample 13 by utilizing the property of the aluminum foil that is easily plastically deformed. By pressing the aluminum foil 15 sufficiently to hold it in a close contact state, the metal phase sample wrapping body 16 is formed as shown in FIG. 1 (c).

The gold phase sample envelope 16 thus obtained 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 cylindrical test piece 17 having a diameter of about 30 mm and a height of about 20 mm and having a bottom end face as shown in FIG. 2 is obtained.

The gold phase test specimen 17 thus obtained is composed of a cured resin portion 17a made of bakelite or the like and a gold phase sample 13 buried in the resin portion 17a.
7b is polished in the usual manner and, if necessary, etched to obtain a polished edge 13a of the gold phase sample 13.
A gold phase observation surface is formed, and a metal phase test is performed on the thickness and physical properties of the oxide film 11a in the gold phase sample 13 using a well-known metal microscope and a scanning electron microscope.

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

Furthermore, a tantalum foil 14 is wound around the entire peripheral surface of the gold phase sample 13 except for the edge surface 13a, and the tantalum foil 14 is pressed and covered with an aluminum foil 15. As a result, the tantalum foil 14 comes into close contact with the peripheral surface of the gold phase sample 13 and this state is maintained by the characteristics of the aluminum foil 15.
3 and the tantalum foil 14 are closely held without any gap. Then, when the gap was measured for the gold phase test specimen 17 obtained by the method of the present invention, the gap g ₁ between the gold phase sample 13 and the tantalum foil 14 on the outer peripheral side in FIG.
Was zero, and it could be confirmed that the gap g ₂ between the gold 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 set as described above is that the tantalum foil 14 is hardly deformed and therefore has the property of not wrinkling. Since the tantalum foil 14 can be pressed by the easily deformable aluminum foil 15, the close contact state of the tantalum foil 14 with the metal phase sample 13 is determined by the aluminum foil 15.
Is to be held. Moreover, aluminum foil 1
5 has a softness not found in the tantalum foil 14, so that it functions as a kind of cushioning material in the metal phase test body 17, which further suppresses the generation of gaps. It is.

For this reason, even if the metal phase test piece 17 is polished as described above, the polished surface of the metal phase sample 13 may be sagged or the oxide film 11a may be damaged and peeled off. Therefore, the metal phase observation surface, which is the polished surface, can be observed with a metal microscope without any trouble.

Further, as described above, since there is substantially no gap, the etching solution does not leach onto the gold phase observation surface of the gold phase sample, and undesired contamination occurs. There was nothing.

As described in more detail in the present embodiment, the edge 13a of the gold phase sample 13 is not covered with the tantalum foil, and the aluminum foil 15 is entirely covered as described above. Even if it is, since the aluminum foil on the edge surface 13a is peeled off by a slight polishing treatment on the gold phase test body,
The polishing can be completed easily. Aluminum foil 1
In the case of No. 5, it is easier to fully press the tantalum foil 14 against the gold phase sample 13 in the case of the entire wrapping.
4, the polishing process may be further facilitated.

[0029]

Since the present invention can be carried out as described above, a vertically divided gold phase sample is used, and a tantalum foil and an aluminum foil having different characteristics are adhered on the gold phase sample. Then, by embedding this in a resin, a metal phase test body is obtained, whereby the gap easily generated between the cured resin portion and the metal phase sample can be made 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 the surface of the gold phase to be sagged, or cause the etchant to leach out of the gap. Thus, the gold phase test such as the measurement of an oxide film of a gold phase sample can be easily and reliably performed without any trouble.

[Brief description of the drawings]

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

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

FIG. 3 is a process explanatory view showing a pressing method as a method for forming a metal phase test body for 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 press method shown in FIG.

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

FIG. 6A is an enlarged plan view of a main part of the gold phase test piece showing an etching solution leaching state, and FIG. 6B is a vertical sectional front view showing the upper surface sagging state.

[Explanation of symbols]

 Reference Signs List 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 wrapping

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G21C 17/06 G01N 1/36

Claims (1)

(57) [Claims] 1. A test 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 metal microscope to measure the thickness of the oxide film. In order to conduct a metal phase test of the test sample to be performed, in a method of forming a test sample or a metal phase test body by a resin embedding process by a press method or a liquid resin method, prior to the resin embedding process, After obtaining a gold phase sample in which the test sample is vertically divided in the axial direction of the metal tubular sample material, a tantalum foil is wound around the other peripheral surface except for the edge surface of the gold phase sample. A gold phase of a metal tubular sample material, characterized in that a gold phase sample envelope formed by wrapping the entire surface of a foil or the entire surface of a gold phase sample containing the same with an aluminum foil is used. Test body formation method.