JP4492285B2 - Method for producing sample for analysis of inclusions contained in metal aluminum sample - Google Patents

Description

The present invention relates to a method for producing a sample for analysis of inclusions contained in a metal aluminum sample. Specifically, the metal aluminum sample is heated and melted in a mold and cooled while concentrating the inclusions by centrifugal force. The present invention relates to a method for producing a sample for inclusion analysis by solidification.

Non-Patent Document 1 [FRMollard, et.al, Light Metals, 485-500 (1972)] and Non-Patent Document 2 are methods for producing analytical samples used for analysis of inclusions (3) contained in metallic aluminum. In [CHR.J.Semensen, METALLURGICAL TRANSACTIONS B, 12B, 733-743 (1981)], the metal aluminum sample (10) is loaded as it is into the mold (2), heated and melted, and then subjected to centrifugal force. Discloses a method of concentrating inclusions (3), cooling and solidifying them, and that the mold (2) is made of ceramics in terms of heat resistance and strength. Has been.

However, in the conventional manufacturing method, the analysis sample (1) after cooling and solidification is fixed to the ceramic mold (2), and the mold (2) is cut to take out the analysis sample (1). There was a problem that had to be. Further, depending on the type of ceramic, there is also a problem that impurities due to the ceramic are mixed into the analysis sample (1).

Examples of the mold (2) to which the analytical sample (1) does not adhere include those made of graphite. However, in the graphite mold (2), carbide (Al ₄ C ₃ ) is generated, and this is an analytical sample as an impurity. It will be mixed in (1).

F.R.Mollard, et.al, Light Metals, 485-500 (1972) CHR.J.Semensen, METALLURGICAL TRANSACTIONS B, 12B, 733-743 (1981)

Therefore, as a result of intensive investigations to develop a method for producing an inclusion analysis sample (1) without adhering to the mold (2) and without mixing impurities, the present inventor obtained a metal aluminum sample. As (10), the shape along the inner surface shape of the mold (2) is used by forming an anodized film on the surface, and this is loaded into the mold (2) and heated to melt. The present inventors have found that this anodized film can prevent the analysis sample (1) from adhering to the template (2) and mixing of impurities.

That is, the present invention heats the metal aluminum sample (10) in the mold (2) to a molten state, and then concentrates inclusions (3) contained in the metal aluminum sample (10) by centrifugal force. Cooling and solidifying the sample (1) used for the analysis of the inclusions (3),
The metal aluminum sample (10) has a shape along the shape of the inner surface (2a) of the mold (2), and an anodized film is formed on the surface.
Provided is a method for producing an analysis sample (1) of the inclusion (3), wherein the metal aluminum sample (10) is loaded into the mold (2) and heated to a molten state. is there.

According to the production method of the present invention, the anodic oxide film prevents impurities from being mixed from the mold (2), and also prevents sticking to the mold (2). Can be manufactured.

The mold (2) applied to the production method of the present invention is usually in a shape that allows the sample for analysis (1) after cooling to be easily taken out, for example, a cylindrical shape as shown in FIG. . The cylindrical mold (2) shown in FIG. 1 has an inner diameter (d ₂₀ ) of about ₂₀ mm to 40 mm, an outer diameter (d ₂₁ ) of 40 mm to 80 mm, a height (h ₂₁ ) of about 120 mm to 250 mm, and a thickness (t ₂ ) Is about 30 mm to 3 mm, and the depth (h ₂₀ ) is about 100 mm to 200 mm.

The mold (2) may be one in which the inner surface (2a) is made of ceramics, or may be made of graphite. As the graphite, those having a maximum particle size of usually 0.005 mm or more and 0.1 mm or less, preferably 0.06 mm or less are used, and the bulk density is usually 2.3 g / cm ³ or less, preferably 1.8 g / cm ^3. The above is used. Examples of such graphite include “MGY-11” (maximum particle diameter 0.05 mm, bulk density 1.74 g / cm ³ ), “MGY-43” (maximum particle diameter 0.01 mm, manufactured by ESC Corporation, Bulk density 1.85 g / cm ³ ), “MGY-71” (maximum particle diameter 0.04 mm, bulk density 1.80 g / cm ³ ), “MGY-72” (maximum particle diameter 0.04 mm, bulk density 1. 86 g / cm ³ ), “IG-43” (bulk density 1.82 g / cm ³ ) manufactured by Toyo Tanso Co., Ltd., and the like. Ceramics are the same as those used in ordinary production methods, such as high-density sintered mullite, alumina such as recrystallized alumina (Al ₂ O ₃ ), high-density sintered zirconia, boron nitride (BN), Al _2. MgO ₄ is exemplified. Such a mold (2) can be produced, for example, by a method of cutting from a raw material, a mold forming method in which the raw material is put in a mold and fired. The inner surface (2a) of the mold (2) is preferably smooth from the viewpoint that the analytical sample (1) after cooling can be easily taken out.

The metal aluminum may have a high purity of 99.99% or more, or may contain iron or other metal components used for building materials.

The metal aluminum sample (10) has a shape along the inner surface (2a) of the mold, and when a cylindrical mold (2) as shown in FIG. 1 is used, it has a cylindrical shape as shown in FIG. Is used. The outer diameter (d ₁ ) of the metal aluminum sample (10) is slightly smaller than the inner diameter (d ₂₀ ) of the mold, specifically, a small shape of about 0.2 mm to 0.5 mm. The metal aluminum sample (10) is loaded into 2), and it is preferable in that the analytical sample (1) after concentration is easily taken out. The height (h ₁ ) is the depth of the mold (h ₂₀ ). Smaller, usually about 80 mm to 160 mm.

Examples of inclusions contained in the metal aluminum sample (1) include non-metallic compounds such as metal oxides, nitrides, carbides, borides and the like, and the diameter is usually 0.2 μm to 100 μm. Degree.

An anodized film is formed on the surface of the metal aluminum sample (10) used in the present invention. Examples of the anodic oxide film include a sulfuric acid-based anodic oxide film obtained by electrolytic treatment in a sulfuric acid aqueous solution using a metal aluminum sample (10) as an anode and a graphite electrode as a cathode. The thickness of the anodic oxide film is usually 5 μm or more, preferably 10 μm or more because it is difficult to break even when the metal aluminum sample (10) is in a molten state, and usually 100 μm or less, preferably from the viewpoint of ease of formation. 50 μm or less.

The anodized film is a surface that contacts the inner surface (2a) of the mold when the metal aluminum sample (10) is loaded on the mold (2), specifically, as shown in FIG. 2, the metal aluminum sample (10). For example, it is preferable not to form an anodized film on the upper surface (13) that does not contact the mold (2). This metal aluminum sample (10) is useful as a metal aluminum sample (10) for inclusion analysis used for analysis of inclusions contained in metal aluminum because such an anodized film is formed on the surface. is there.

In the production method of the present invention, the metal aluminum sample (10) is loaded into the mold (2) and heated to a molten state. The heating temperature is a temperature at which the metal aluminum sample (10) can be in a molten state, and the inclusion (3) can be rapidly concentrated by centrifugal force. When the inner surface (2a) made of graphite is used as the mold, the temperature is 850 ° C. or less because oxidation of the inner surface of the mold can be suppressed. For the heating, for example, a heater such as an electric heater or an infrared heater is used.

In order to concentrate the inclusion (3) contained in the metal aluminum sample by centrifugal force, for example, the mold (2) loaded with the metal aluminum sample (10) is used in Non-Patent Document 1 [FRMollard, et.al, Mounted in a centrifuge (5) equipped with a holder (4) as disclosed in Light Metals, 485-500 (1972)) and heated by a heater (6) provided in the holder (4). Then, it may be centrifuged. The centrifugal separator (5) shown in FIG. 2 includes a rotating arm (7) that rotates the holder (4) and a housing (8) that surrounds the holder (4) rotated thereby. The rotary arm (7) is rotationally driven by, for example, an electric motor (not shown). The holder (4) is provided with a temperature measuring element (not shown) such as a thermocouple, and the temperature measuring element measures the temperature of the metallic aluminum in the mold (2) and outputs the heater (6). Is adjusted to heat the metallic aluminum to the above temperature.

Centrifugal force is usually 200G (200 times the gravitational acceleration) or more, preferably 300G (300 times the gravitational acceleration) or more in that the inclusion (3) can be quickly concentrated. In view of the strength of the holder (4), the rotating arm (7), etc., it is usually 800G or less, preferably about 500G or less.

The time required for concentration varies depending on the type and content of inclusions contained in the metal aluminum, the heating temperature, the degree of centrifugal force, etc., but is usually about 0.5 to 3 hours.

Inclusions contained in the metal aluminum sample are centrifuged by centrifugal force and concentrated on the bottom surface (11) side. After concentration, cooling from the bottom surface (11) side and solidifying, the inclusion (3) is concentrated on the bottom surface (11) and collected as shown in FIG. ) Can be obtained.

Since the metal aluminum sample (10) has a shape along the shape of the inner surface (2a) of the mold (2), the anode formed on the surface of the metal aluminum sample (10) even when centrifugal force is applied. The oxide film is not destroyed and the molten metal aluminum is centrifuged without direct contact with the mold (2) while the anodized film is formed on the surface. 1) can be obtained.

In order to analyze the inclusions in the metal aluminum by the analysis sample (1) thus obtained, the analysis sample (1) is cut in the same manner as usual, and the inclusions of the cut surface (14) What is necessary is just to observe the bottom face (11) vicinity where (3) accumulated by the microscope. The cut surface (14) after cutting is preferably polished. The microscope is not particularly limited, and is selected as appropriate according to the size and type of the inclusion (3) as usual, for example, an optical microscope such as a stereomicroscope, a polarizing microscope, a phase contrast microscope, a scanning Type electron microscope. Further, the inclusion component can be analyzed by an electron beam microanalyzer that is incorporated in, for example, a scanning electron microscope and analyzes X-rays generated by electron beam irradiation.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by this Example.

Example 1
[Make mold]
A high-density graphite “MGY-43” (maximum particle diameter 0.01 mm, bulk density 1.85 g / cm ³ ) manufactured by SCE Co., Ltd., is cylindrical and has an outer diameter (d ₂₁ ) 56 mm, height (h ₂₁ ), inner diameter (d ₂₀ ) 27 mm, depth (h ₂₀ ) 150 mm mold (2) was prepared.

[Preparation of metal aluminum sample]
A cylindrical metal aluminum sample (10) having an outer diameter (d ₁ ) of 26.6 mm and a height (h ₁ ) of 120 mm is prepared, and this is used as an anode and a graphite electrode as a cathode. Then, an electric current was applied for 20 minutes at a temperature of 20 ° C. and a current density of 0.13 A / cm ² to form an anodized film having a thickness of 10 μm on the bottom surface (11) and side surface (12) of the metal aluminum sample (10). A metal aluminum sample (10) for inclusion analysis was obtained. The mass of the metal aluminum sample after forming the anodized film was 180 g.

[Heating and concentration]
The metal aluminum sample (10) prepared above is loaded into the mold (2) prepared above, heated to 780 ° C. using a centrifugal separator (5) as shown in FIG. A 400 G centrifugal force was applied at temperature for 1 hour. Then, while applying the same centrifugal force, the mixture was cooled to 300 ° C. over 1 hour to solidify, and then allowed to cool to room temperature (about 25 ° C.), and an analytical sample (1) was taken out. When the mold (2) after taking out the analytical sample was visually observed, no cracks, chips, cracks, etc. were observed. As shown in FIG. 3 (b), the analytical sample (1) was cut in the height direction, the cut surface (14) was polished, and the vicinity of the bottom surface (11) was observed with a scanning electron microscope. Twenty-two inclusions (3) having a size of 1 to 5 μm were observed in an area of 10 mm × 10 mm. These inclusions (3) were all aluminum oxide. In addition, although the anodized film formed on the surface showed cracks, there was no destruction such as peeling that exposed metal aluminum.

Using the same mold (2), a metal aluminum sample (10) was prepared in the same manner as described above, and the operation of centrifuging was further repeated 20 times, but no cracks or the like were found in the mold (2).

Example 2
The mold was operated in the same manner as in Example 1 except that high density graphite “MGY-11” (maximum particle diameter 0.05 mm, bulk density 1.74 g / cm ³ ) manufactured by ESC Corporation was used as the high density graphite. (2) was created. An analytical sample (1) was obtained in the same manner as in Example 1 except that the template (2) prepared above was used instead of the template prepared in Example 1. When the mold (2) after taking out the analytical sample was visually observed, no cracks, chips, cracks, etc. were observed. The sample for analysis (1) was 179 g. The sample for analysis was cut and polished in the same manner as in Example 1, and the vicinity of the bottom surface (11) of the cut surface (14) was observed with a scanning electron microscope. 25 (3) were observed. These inclusions (3) were all aluminum oxide. In addition, although the anodized film formed on the surface showed cracks, there was no destruction such as peeling that exposed the metal aluminum.

Using the same mold (2), a metal aluminum sample (10) was prepared in the same manner as described above, and the process of centrifuging was further repeated twice. However, no cracks or the like were found in the mold (2).

Comparative Example 1
An analytical sample (1) was obtained in the same manner as in Example 1 except that the anodized film was not formed on the columnar metal aluminum sample (10), but was directly loaded into the mold (2). When the mold (2) after taking out the analytical sample was visually observed, no cracks, chips, cracks, etc. were observed. The mass of this analytical sample (1) was 173 g. When this analytical sample was cut and polished in the same manner as in Example 1, and the vicinity of the bottom surface (11) of the cut surface (14) was observed with a scanning electron microscope, inclusions of 1 μm to 5 μm in an area of 10 mm × 10 mm were observed. 125 (3) were observed. Most of these inclusions (3) were aluminum carbide.

Using the same mold (2), a metal aluminum sample (10) was prepared in the same manner as described above, and the process of centrifuging was further performed once. As a result, cracks were found in the cooled mold (2). .

It is a perspective view which shows typically an example of the casting_mold | template and metal aluminum sample which are applied to the manufacturing method of this invention. It is sectional drawing which shows typically an example of the centrifuge used for the manufacturing method of this invention. It is a perspective view which shows typically a mode that the sample (a) for analysis obtained by the manufacturing method of this invention and what cut | disconnected this (b) were seen from the bottom face side.

Explanation of symbols

1: Sample for analysis of metal aluminum 10: Metal aluminum sample
11: Bottom surface 12: Side surface 13: Upper surface 14: Cut surface h ₁ : Height d ₁ : Outer diameter 2: Mold
2a: mold inner surface h _21: Height h _20: Depth t _2: thickness d _20: inside diameter d _21: outer diameter 3: Inclusions 4: Holder 5: centrifuge 6: heater 7: Rotation arm 8: Housing

Claims (4)

After the metal aluminum sample is heated to a molten state in the mold, the inclusions contained in the metal aluminum sample are concentrated by centrifugal force, cooled and solidified to produce a sample used for analysis of the inclusions And how to
The metal aluminum sample has a shape along the inner surface of the mold, and an anodized film is formed on the surface,
The method for producing a sample for analysis of inclusions, wherein the metal aluminum sample is loaded into the mold and heated to a molten state. The manufacturing method according to claim 1, wherein the mold has an inner surface made of graphite or ceramics. The manufacturing method according to claim 1, wherein the anodized film has a thickness of 5 μm to 100 μm. An analysis sample is produced by producing an analytical sample by the production method according to any one of claims 1 to 3, cutting the obtained analytical sample, and observing the cut surface with a microscope. Method.

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