JP2012018099A - Emission spectrophotometer, sample holding stage, and emission spectral analysis method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an emission spectrophotometer capable of accurately analyzing a metal sample with a small size of a diameter 15 mm or less by a spark discharge spectral analysis method, and quickly analyzing the sample without substantially destroying the same.SOLUTION: The emission spectrophotometer 1 of the present invention comprises a sample supporting base 10 with an opening 13, and an electrode 4 provided below an exposed portion 3d, which is exposed from the opening 13, of a metal sample 3 placed on the surface 10a side of the sample supporting base 10. Many spark discharges are generated in an inert gas atmosphere between the metal sample 3 and the electrode 4, and emission light for every spark discharge is dispersed to quantify elements in the metal sample. A ring member 11 made of an electrical insulation material for preventing a discharge into a portion 14 adjacent to the opening on the back side of the sample supporting base at spark-discharging is provided, and the opening diameter of the surface opening located on the surface of the sample supporting base is 15 mm or less.

Description

  The present invention relates to an emission spectroscopic analysis apparatus using spark discharge, a sample holding stage used in the apparatus, and an emission spectroscopic analysis method. The present invention particularly relates to an emission spectroscopic analysis apparatus and method capable of analyzing even a small sample that could not be analyzed conventionally.

  One of the elemental analysis methods for metal samples is spark discharge emission spectroscopy. This is a method in which a number of spark discharges are generated in an inert gas atmosphere between a metal sample and an electrode facing the metal sample, and the light emission of each spark discharge is analyzed to quantify the elements in the metal sample. It is.

  FIG. 11 shows a general configuration of a sample support table (light emitting stand) that supports a metal sample. The metal sample 3 having the flat surface portion 3a is placed on the surface 10a side of the sample support 10 having the opening 13. Here, the opening 13 is a space surrounded by the opening edge 13 a of the sample holder 10. On the back surface 10 b side of the sample support 10, the electrode 4 is disposed at a position below the exposed portion of the flat portion 3 a of the metal sample exposed from the opening 13 so as to face the exposed portion. The metal sample 3 is connected to the cathode side of the DC power supply device 12, and the electrode 4 is connected to the anode side. The opening diameter R2 of the opening 13 is larger than 15 mm. When the DC power supply device 12 is operated, a spark discharge is generated between the exposed portion of the metal sample 3 and the electrode 4. Such a conventional spark discharge optical emission spectrometer is described in Patent Document 1, for example.

  Further, in Patent Document 2, by providing an electrically insulating elastic member in the vicinity of the portion adjacent to the opening on the surface of the sample support table, the opening of the sample support table can be obtained even if the flat surface of the metal sample is not sufficiently polished. A technique is described in which the portion can be sufficiently sealed so that the airtightness of the discharge chamber is not impaired.

JP 2006-177922 A JP 2000-292355 A

  However, the conventional emission spectroscopic analyzers described in Patent Documents 1 and 2 have a restriction that the opening diameter R2 of the opening (see FIG. 11) must be larger than 15 mm. That is, when the opening diameter R2 is 15 mm or less, the sample support 10 is usually made of a metal material. Therefore, under normal spark discharge conditions, the sample support 10 is discharged to the portion 14 adjacent to the opening 13 on the back surface of the sample support 10. This is because if the sample support 10 itself is discharged in this manner, the analysis accuracy deteriorates and the emission spectroscopic analyzer itself may be destroyed.

  In addition, for a metal sample having a size of 15 mm or less, the opening of the sample support base cannot be completely covered with the metal sample, and inert gas (argon gas) leaks from the discharge chamber, resulting in abnormal discharge of the spark discharge. , Can not perform an effective analysis. Therefore, the conventional emission spectroscopic analyzer has a problem that only a metal sample having a flat surface portion 3a serving as an analysis surface can be analyzed with a diameter larger than 15 mm.

  For this reason, when analyzing a small metal sample having a diameter of 15 mm or less, a method other than the spark discharge emission spectroscopic analysis method had to be employed. For example, as a conventional analysis method for quantifying carbon atoms in a metal sample, for example, a combustion-infrared absorption method is common (JIS G1211). However, this analysis method is an analysis method in which the surface of a metal sample is cut and chips are measured, and is not a non-destructive analysis method because a part of the metal sample is used. Further, as a conventional analysis method for quantifying nitrogen atoms in a metal sample, for example, a melting thermal conductivity method is common. However, this is also an analysis method in which a metal sample is made into a solution to prepare an analysis sample, and is not a non-destructive analysis method because a part of the metal sample is used. In addition, when spark discharge emission spectrometry cannot be applied, elements in metal samples can be quantified by wet chemical analysis methods such as ICP emission analysis (JIS G1258). Must be made into a solution with an acid, and it takes several hours from sampling to completion of analysis, and skill is also required. In addition, these measurement methods cannot be applied to the analysis of the surface treatment layer of a metal material subjected to carburizing and quenching treatment or the like because the sample surface is removed by grinding or cutting treatment.

  On the other hand, the spark discharge optical emission spectrometry is a method in which the surface of analysis is vaporized by spark discharge, the light emitted at that time is dispersed with a spectroscope, the composition is analyzed from the wavelength, and the content is analyzed from the intensity. Strictly speaking, although a spark discharge trace remains after measurement, a part of the metal sample is not used for analysis, and can be said to be a substantially nondestructive analysis method. However, the conventional spark discharge emission spectroscopic analysis method uses a metal sample having a size larger than 15 mm as an analysis object from the viewpoint of analysis accuracy, and the analysis accuracy is inferior for analysis of a metal sample having a size of 15 mm or less. Cannot be used.

  Therefore, in view of the above problems, the present invention can accurately analyze a small-sized metal sample having a diameter of 15 mm or less by a spark discharge optical emission spectrometry, and can perform a substantially nondestructive analysis of the sample quickly. It is an object to provide an emission spectroscopic analysis apparatus, a sample holding stage used in the apparatus, and an emission spectroscopic analysis method.

  As a result of intensive studies, the inventors of the present invention have a configuration in which a spark discharge is not generated in a portion adjacent to the opening on the back surface of the sample support base, and the discharge applied to the sample without strictly controlling the discharge conditions. The idea that the area can be easily reduced in diameter has been obtained, and the present invention has been completed.

That is, in view of the above problems, the gist of the present invention is as follows.
(1) a sample support for placing the metal sample so that the flat part of the metal sample having an opening and a flat part is located on the surface side;
On the back surface side of the sample support base, an electrode is disposed at a position below the exposed portion of the flat portion of the metal sample exposed from the opening and facing the exposed portion at a predetermined interval;
An emission spectroscopic analyzer for quantifying the elements in the metal sample by generating a number of spark discharges in an inert gas atmosphere between the metal sample and the electrode and spectroscopically analyzing the light emission of each spark discharge. Because
A ring member made of an electrically insulating material for preventing discharge to a portion adjacent to the opening on the back surface of the sample support base during spark discharge;
The ring member is arranged such that the center line of the opening coincides with the center line of the opening of the sample support base,
An emission spectroscopic analyzer, wherein an opening diameter of a surface opening located on the surface of the sample support is 15 mm or less.

  (2) The emission spectroscopic analysis apparatus according to (1), wherein the ring member is disposed so that at least an inner diameter side portion of the ring member is exposed when viewed from a back surface side of the sample support base.

(3) The opening of the sample support base is an opening provided in a stepped recess provided for fixedly mounting the ring member,
The emission spectroscopic analyzer according to (1), wherein an opening diameter of the opening is larger than an opening diameter of the ring member.

(4) An emission spectroscopic analyzer for generating a number of spark discharges between the metal sample and the electrode in an inert gas atmosphere, and quantifying the elements in the metal sample by spectroscopically analyzing the light emission of each spark discharge. A sample holding stage used for
A ring member having an opening diameter of 15 mm or less made of an electrically insulating material;
A sample support having a stepped recess for fixing and mounting the ring member,
The sample holding stage, wherein the stepped recess is provided with an opening having an opening diameter larger than the opening diameter of the ring member.

(5) Place a metal sample having a flat portion on the surface side of the sample support base having an opening so that the flat portion is located on the surface side of the sample support base;
On the back surface side of the sample support base, an electrode facing the exposed portion at a predetermined interval is disposed at a position below the exposed portion of the flat portion of the metal sample exposed from the opening,
An emission spectroscopic analysis method that quantifies elements in the metal sample by generating a number of spark discharges in an inert gas atmosphere between the metal sample and the electrode and spectroscopically analyzing the light emission of each spark discharge. And
During spark discharge, a ring member made of an electrically insulating material for preventing discharge to a portion adjacent to the opening on the back surface of the sample support base is used, and the center line of the opening is the center line of the opening of the sample support base. Arrange to match,
An emission spectroscopic analysis method, wherein an opening diameter of a surface opening located on the surface of the sample support is 15 mm or less.

(6) The metal sample is steel having a carburized or nitrided surface.
The emission spectroscopic analysis method according to (5), wherein the quantitative analysis element in the metal sample is carbon or nitrogen.

  (7) The emission spectroscopic analysis method according to (6), wherein a discharge time of the spark discharge is set so that elemental analysis can be performed in a depth direction within 20 μm from the surface of the metal sample.

  According to the present invention, during spark discharge, a ring member made of an electrically insulating material that prevents discharge to a portion adjacent to the opening on the back surface of the sample support base is provided such that the center line of the opening of the ring member is Since it is arranged so as to coincide with the center line of the opening of the sample support base, even a small metal sample having a diameter of 15 mm or less, which is impossible to measure with a conventional emission spectroscopic analyzer, is highly accurate by spark discharge optical emission spectrometry. Analysis can be performed, and a substantially non-destructive analysis can be quickly performed on the sample.

It is the schematic which shows an example of the whole structure of the emission-spectral-analysis apparatus according to this invention. It is a figure which shows the sample holding stage used for the emission-spectral-analysis apparatus according to this invention, (a) is a perspective view when this stage is seen from the surface diagonally upper direction, (b) is sectional drawing containing the diameter of an opening part, and is metal The state before installing the sample 3 is shown, (c) is a cross-sectional view similar to (b), showing the state where the metal sample 3 is installed, and (d) is the sample support stage from the sample holding stage of (b). It is sectional drawing which extracted 10 only. It is the figure which observed the sample holding stage shown in FIG. 2 from the back surface side. It is sectional drawing containing the diameter of the opening part of another sample holding stage according to this invention. It is sectional drawing including the diameter of the opening part of another sample holding stage according to this invention. It is the figure which showed the relationship between a discharge peak current and a discharge scar diameter about spark discharge conditions. It is the figure which showed the relationship between a discharge frequency and a discharge scar diameter about spark discharge conditions. It is the figure which showed the relationship between discharge time and analysis depth about spark discharge conditions. It is the figure which showed the relationship between the analysis depth and carbon amount in Example 2. FIG. It is the figure which showed the relationship between the discharge time in Example 2, and carbon content. It is sectional drawing containing the diameter of the opening part of the sample holding stage of the conventional emission-spectral-analysis apparatus.

  Hereinafter, the present invention will be described in more detail with reference to the drawings. In principle, the same components are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 1, the emission spectroscopic analysis apparatus 1 of the present invention using spark discharge includes a light emitting unit, a spectroscopic unit, a photometric device 8, and a data processing device 9. The light emitting unit is composed of the discharge device 2, the metal sample 3, and the electrode 4, and is sparked many times between the metal sample 3 and the electrode 4 in response to a signal from the discharge device 2 in an inert gas atmosphere such as Ar gas. This is the part that generates electric discharge. The spectroscopic unit includes the slit 5, the diffraction grating 6, and the detector 7, and is a part that splits light emitted for each spark discharge generated in the light emitting unit. The spectral line detected by the detector 7 of the spectroscopic unit is processed by the photometric device 8. Based on the spectral line intensity input from the photometric device 8, the content of the element in the metal sample 3 is obtained by the data processing device 9. The metal sample 3 is an object to be measured and is also an electrode.

(Embodiment 1)
The sample holding stage of the light emitting unit including the main characteristic configuration of the emission spectroscopic analysis apparatus 1 of the present invention will be described in detail with reference to FIG. The sample holding stage includes a ring member 11 having an opening diameter R1 of 15 mm or less made of an electrically insulating material, and a step recess 13b (see FIG. 2D) for fixing and mounting the ring member 11. The step recess 13b is provided with an opening 13 having an opening diameter R2 (see FIG. 2B) larger than the opening diameter R1 of the ring member 11.

  Here, the opening 13 of the sample support 10 means an opening provided in the step recess 13b for fixing and mounting the ring member in the case of FIG. 2, and is a space surrounded by the opening edge 13a. . Further, as shown in FIG. 2B, the opening 15 of the ring member 11 is a space surrounded by the inner diameter end surface 15a of the ring member. The ring member 11 is arranged so that the center line of the opening 15 coincides with the center line of the opening 13 of the sample support base. Moreover, the opening 15 of the ring member can be continuous with the opening 13 of the sample support base to form a discharge space.

  As described above, the sample support 10 made of a metal material has the opening 13 and can place the metal sample 3 having the flat surface portion 3a so that the flat surface portion 3a is located on the surface 10a side. On the back surface 10b side of the sample support base, the discharge region is located below the exposed portion 3d of the flat portion 3a of the metal sample 3 exposed from the opening 13 (see FIG. 2C, hereinafter referred to as “discharge region”). And an electrode 4 made of a conductive material such as tungsten is disposed so as to face each other with a predetermined distance d. The metal sample 3 is connected to the cathode side of the DC power supply device 12, and the electrode 4 is connected to the anode side. The sample support 10 is grounded.

  Here, since the opening diameter R2 of the opening 13 of the sample support base provided in the step recess 13b is larger than the opening diameter R1 of the ring member 11, the vicinity of the electrode 4 on the back surface 10b side of the sample support base. In the portion, the electrically insulating material is exposed. FIG. 3 is a view of the sample holding stage shown in FIG. 2 observed from the back surface side, and it can be seen that the ring member 11 is arranged so that the inner diameter side portion thereof is exposed when viewed from the back surface 10b side. For this reason, even if the opening diameter R1 of the ring member 11 is 15 mm or less, which is smaller than the conventional one, discharge to the portion 14 adjacent to the opening 13 in the back surface 10b of the sample support base is prevented during spark discharge. be able to. In other words, even if the opening diameter R1 of the ring member 11 is 15 mm or less, the electric insulating material is not subjected to spark discharge, and therefore the actual spark discharge is limited to the exposed portion 3d of the metal sample 3. Is done. In addition, the diameter R3 of the circle shown by the broken line in FIG. 3 is the outer diameter of the ring member 11 as shown in FIG.

  As a result, the opening diameter R (see FIG. 2C) of the surface opening located on the surface 10a of the sample support base becomes the opening diameter R1 of the opening of the ring member 11 in this embodiment, which is 15 mm or less. It is also possible to place a small-sized metal sample having a diameter of 15 mm or less, which could not be measured with a conventional emission spectroscopic analyzer, on the sample support table to close the surface opening. Therefore, the spark discharge emission spectroscopic analysis can be performed with high accuracy, and the non-destructive analysis of the metal sample can be performed rapidly.

(Embodiment 2)
In the sample holding stage shown in FIG. 4, the ring-shaped member 11 is fitted inside the opening 13 of the sample support 10 that does not have a stepped recess as shown in FIG. That is, the entire outer peripheral surface of the ring member 11 is in contact with the entire inner diameter edge 13a of the opening 13 of the sample support. For this reason, the opening diameter R2 of the sample support base and the outer diameter R3 of the ring member 11 are substantially equal. The ring member 11 is arranged so that the center line of the opening 15 coincides with the center line of the opening 13 of the sample support base. Moreover, the opening 15 of the ring member has a space common with the opening of the sample support 10, and this can form a discharge space.

  Also in this embodiment, the electrically insulating material is exposed in the vicinity of the electrode 4 on the back surface 10b side of the sample support base. And the ring member 11 is arrange | positioned so that the whole may be exposed seeing from the back surface 10b side. For this reason, even if the opening diameter R1 of the ring member 11 is 15 mm or less, which is smaller than the conventional one, discharge to the portion 14 adjacent to the opening 13 in the back surface 10b of the sample support base is prevented during spark discharge. be able to. That is, even if the opening diameter R1 of the ring member 11 is 15 mm or less, the electric insulating material is not subjected to a spark discharge, so that the spark discharge is limited to the exposed portion 3d of the metal sample.

  As a result, the opening diameter R of the surface opening located on the surface 10a of the sample support base is also the opening diameter R1 of the opening of the ring member 11 in this embodiment, which can be 15 mm or less. A small-sized metal sample having a diameter of 15 mm or less, which could not be measured by the emission spectroscopic analyzer, can be placed on the sample support to close the surface opening. Therefore, the spark discharge emission spectroscopic analysis can be performed with high accuracy, and the non-destructive analysis of the metal sample can be performed rapidly.

(Embodiment 3)
In the sample holding stage shown in FIG. 5, the ring member 11 is provided so as to cover the portion 14 adjacent to the opening 13 in the back surface 10b of the sample support base. For this reason, the opening diameter R1 of the ring member 11 and the opening diameter R2 of the sample support base are substantially equal. The ring member 11 is arranged so that the center line of the opening 15 coincides with the center line of the opening 13 of the sample support base. Further, the opening 15 of the ring member can be continuous with the opening 13 of the sample support base to form a discharge space.

  Also in this embodiment, the electrically insulating material is exposed in the vicinity of the electrode 4 on the back surface 10b side of the sample support base. And the ring member 11 is arrange | positioned so that the whole may be exposed seeing from the back surface 10b side. For this reason, even if the opening diameter R1 of the ring member 11 is 15 mm or less, which is smaller than the conventional one, discharge to the portion 14 adjacent to the opening 13 in the back surface 10b of the sample support base is prevented during spark discharge. be able to. That is, even if the opening diameter R1 of the ring member 11 is 15 mm or less, the electric insulating material does not cause a spark discharge, and therefore the spark discharge is limited to the exposed portion 3d of the metal sample.

  As a result, the opening diameter R of the surface opening located on the surface 10a of the sample support is different from the first and second embodiments in the present embodiment, and becomes the opening diameter R2 of the sample support, which is 15 mm or less. be able to. Therefore, it is possible to place a small-sized metal sample having a diameter of 15 mm or less, which was impossible to measure with a conventional emission spectroscopic analyzer, on the sample support table, thereby closing the surface opening. Therefore, the spark discharge emission spectroscopic analysis can be performed with high accuracy, and the non-destructive analysis of the metal sample can be performed rapidly.

(Matters common to each embodiment)
In the first and second embodiments, it is preferable to fit the ring member 11 into the sample support 10 so that the surface of the sample support 10 and the ring member 11 are substantially flush with each other. In the third embodiment, the surface 10a of the sample support 10 is preferably flat. Thereby, the flat part 3a of the metal sample can be placed in close contact with the surface 10a of the sample support, and the opening 13 of the sample support or the opening 15 of the ring member can be sealed by the flat part 3a.

  Further, the ring member 11 is arranged so that the center line of the opening 15 coincides with the center line of the opening 13 of the sample support base, by performing a spark discharge uniformly on the exposed portion 3d of the metal sample, This is to ensure analysis accuracy.

  Examples of the electrically insulating material constituting the ring member 11 include ceramics such as alumina, zirconia, and silica.

  The optimum values of the opening diameter R1 of the ring member, the ring width W, and the distance d between the discharge region and the electrode vary depending on the size of the sample. An example is shown below.

  The opening diameter R1 of the ring member is preferably as small as 15 mm or less. This is because a smaller metal sample can be measured as R1 is smaller. However, it is preferably 1 mm or more, for example, about 2 mm. This is because if R1 is less than 1 mm, a sufficient discharge area for analysis cannot be secured, and the analysis accuracy may be lowered.

  In addition, if the ring width W of the ring member 11 is too narrow, exposure of the electrically insulating material to the back surface 10b becomes insufficient, and there is a possibility of discharging to the opening end 13a of the opening of the sample support base.

  The distance d between the discharge region and the electrode 4 is, for example, about 3 mm.

  And according to these embodiments, it becomes possible to analyze a small-sized metal sample within a range of 1 to 15 mm in diameter with a spark discharge optical emission spectrometer, and the time required for analysis is reduced to the conventional several hours. In comparison, it can be shortened to several tens of seconds. Therefore, in particular, when analyzing a large number of the same kind of metal samples, extraction analysis has been performed so far, and it is very useful in that it can be performed in a short time even if total analysis is performed.

(Analytical object)
Next, the metal sample 3 which is an analysis object will be described. The metal sample 3 that can be measured by the emission spectroscopic analysis apparatus of the present invention is not particularly limited, but a sample having an arbitrary size within a range of 1 to 15 mm in diameter that could not be analyzed by the spark discharge optical emission spectrometry in the past. If so, the benefits of the present invention can be fully received. For example, a gear having a diameter of about 3 mm made of steel whose surface is carburized or nitrided can be used. When analyzing the upper or lower surface of the gear having an opening of about 1 mm for inserting the rotation shaft at the center of the flat upper and lower surfaces, the measurement surface is about 2 mm. By installing it on the sample holding stage, it can be analyzed by spark discharge optical emission spectrometry. When the analysis surface is carburized, carbon is quantified in the depth direction, and when nitriding is performed, nitrogen is quantified in the depth direction.

(Spark discharge condition)
Next, the discharge conditions for spark discharge will be described. Since the emission spectroscopic analysis apparatus 1 of the present invention digitizes the spark discharge circuit that controls the discharge apparatus 2, the spark discharge conditions can be arbitrarily changed by a computer. The spark current value can be changed in units of 1 A within a range of 1 to 250 A, and the discharge frequency can be changed in units of 1 Hz within a range of 100 to 600 Hz. The spark discharge waveform (peak current, number of peaks, spark duration time) can be changed by, for example, dividing the plateau region of the peak current 1 to 255A and the discharge 1 to 200 and setting each current value at 0 to 30A. .

  Here, the conditions affecting the discharge area are: 1. Spark discharge current value (A) 2. Spark discharge frequency (Hz) 3. Spark discharge waveform (peak current, number of peaks, spark duration time) The distance d between the electrode tip and the sample. On the other hand, the condition affecting the depth of elemental analysis is the discharge time (s) of spark discharge. FIG. 6 is a diagram showing the relationship between the discharge peak current and the discharge scar diameter for the spark discharge conditions. It can be seen that there is a correlation between the spark discharge current value and the discharge area, and the discharge area decreases as the current value decreases. FIG. 7 is a diagram showing the relationship between the discharge frequency and the discharge scar diameter. There is a correlation between the spark discharge frequency and the discharge area, and it can be seen that the discharge area decreases as the frequency decreases. FIG. 8 is a diagram showing the relationship between the discharge time and the analysis depth. It can be seen that there is a correlation between the spark discharge time and the discharge depth, and that the discharge depth increases as the discharge time is increased.

  By appropriately combining these conditions, the optimum discharge conditions can be arbitrarily set in consideration of the dimensions (R1 to R3) of the sample holding stage according to the present invention.

  Here, in the present invention, since there is the ring member 11, the region where the metal sample 3 is actually discharged is limited to the exposed portion 3 d shown in FIG. 2C, but the ring member 11 is temporarily provided. If it is assumed that there is not, it is preferable from the following points to set the discharge conditions so that the discharge area on the back surface 10b is larger than R1.

  That is, when performing elemental analysis from the surface of the metal sample in the depth direction by the spark discharge optical emission spectrometry, analysis with higher accuracy becomes possible. When the discharge conditions are not set as described above, although the spark discharge is small, the spark impact is directly applied to the discharge region without being relaxed by the ring member 11. Then, since the speed at which the discharge trace is dug in the depth direction increases, analysis with sufficient accuracy in the depth direction cannot be performed. On the other hand, if the discharge conditions are set as described above, after the spark discharge is mitigated by the ring member 11, a spark impact is applied to the discharge region, so that the speed at which the discharge trace is dug in the depth direction is reduced. For this reason, elemental analysis can be performed with sufficient accuracy in the depth direction.

  In addition, in the first embodiment shown in FIG. 2, since there is the ring member 11, the region where the metal sample 3 is actually discharged is limited to the exposed portion 3d shown in FIG. When it is assumed that the member 11 is not provided, it is preferable to set the discharge conditions so that the discharge area on the back surface 10b is smaller than the opening diameter R2 of the sample support base. Otherwise, there is a possibility of discharging to the adjacent portion 14 of the opening 13.

  As for the discharge time, when performing the depth direction analysis of the steel whose surface has been carburized or nitrided, the discharge time of the spark discharge is set so that elemental analysis can be performed in the depth direction within 20 μm from the surface. It is preferable.

Example 1
The following example shows that a metal sample having a small diameter, which could not be measured by the spark discharge optical emission spectrometry, can be quantified without error from the case of using other analysis methods. Two types of samples A and B having different carbon contents are subjected to quantitative analysis of carbon by the emission spectroscopic analyzer of the present invention (Example), while the same sample is subjected to combustion-infrared absorption method (JIS G1211). ) Was also quantified (comparative example). The spark discharge emission analysis of the example was measured using the apparatus of FIG. The apparatus dimensions were R1: φ1.8 mm, R2: φ55 mm, and d: 2.1 mm. For each sample, Table 1 shows the discharge mark depth after performing the spark discharge emission analysis of the example, and the time taken for measurement in the example and the comparative example. In addition, Table 2 shows the results of the measurement of Examples and Comparative Examples using three samples for each of Samples A and B and calculating the average value of the carbon content.

  With the emission spectroscopic analysis apparatus of the present invention, it is possible to carry out quantitative analysis of carbon by the analysis method for small-diameter metal samples A and B, which could not be measured by the spark discharge emission spectroscopic analysis method. As shown, it was possible to obtain a value substantially in agreement with the measurement result by the combustion-infrared absorption method. On the other hand, as shown in Table 1, the measurement time was significantly shortened as compared with the combustion-infrared absorption method.

(Example 2)
A steel sample subjected to gas carburizing treatment (sample size, φ5.0 mm) was set in the spark discharge optical emission spectrometer of the present invention shown in FIG. 2, and carbon was used under the same conditions as in Example 1 except for the discharge time. The depth distribution of the quantity was measured. Table 3 shows the relationship between the discharge time, analysis depth, and carbon content. FIG. 9 shows the relationship between the analysis depth and the carbon content, and FIG. 10 shows the relationship between the discharge time and the carbon content. From these results, it can be seen that the amount of carbon increases toward the surface, and the amount of carbon decreases toward the inside.

  For a small-diameter metal sample that has been subjected to carburizing treatment, the ICP emission analysis method or the like could not measure the depth distribution of the carbon content. According to the emission spectroscopic analyzer of the present invention, this is measured. It became possible.

  According to the present invention, during spark discharge, a ring member made of an electrically insulating material for preventing discharge to a portion adjacent to the opening on the back surface of the sample support base is provided, and the opening of the ring member is the sample support base. Because it is arranged so as to be common or continuous with the aperture of the metal, a spark sample emission spectroscopic analysis method can accurately analyze a metal sample having a diameter of 15 mm or less, which could not be measured by a conventional emission spectroscopic analyzer. In addition, a substantially non-destructive analysis can be quickly performed on the sample.

DESCRIPTION OF SYMBOLS 1 Emission-spectral-analysis apparatus 3 Metal sample 3a The plane part of a metal sample 3d The exposed part of the plane part of a metal sample 4 Electrode 10 Sample support stand 10a The surface of a sample support stand 10b The back surface of a sample support stand 11 Ring member 13 Opening of a sample support stand 13a Opening edge of the sample support 13b Stepped recess 14 Part adjacent to the opening on the back of the sample support 15 Opening of the ring member 15a Opening edge of the ring member R1 Opening diameter of the ring member R2 Opening diameter of the sample support base R3 Ring Outer diameter of member

Claims (7)

A sample support for placing the metal sample so that the flat part of the metal sample having an opening and a flat part is located on the surface side;
On the back surface side of the sample support base, an electrode is disposed at a position below the exposed portion of the flat portion of the metal sample exposed from the opening and facing the exposed portion at a predetermined interval;
An emission spectroscopic analyzer for quantifying the elements in the metal sample by generating a number of spark discharges in an inert gas atmosphere between the metal sample and the electrode and spectroscopically analyzing the light emission of each spark discharge. Because
A ring member made of an electrically insulating material for preventing discharge to a portion adjacent to the opening on the back surface of the sample support base during spark discharge;
The ring member is arranged such that the center line of the opening coincides with the center line of the opening of the sample support base,
An emission spectroscopic analyzer, wherein an opening diameter of a surface opening located on the surface of the sample support is 15 mm or less.   2. The emission spectroscopic analysis apparatus according to claim 1, wherein the ring member is disposed so that at least an inner diameter side portion of the ring member is exposed when viewed from a back surface side of the sample support. The opening of the sample support is an opening provided in a step recess provided for fixedly mounting the ring member,
The emission spectroscopic analysis apparatus according to claim 1, wherein an opening diameter of the opening is larger than an opening diameter of the ring member. Used in an emission spectroscopic analyzer that quantifies the elements in a metal sample by generating a number of spark discharges between the metal sample and an electrode in an inert gas atmosphere and spectrally analyzing the light emission of each spark discharge. A sample holding stage,
A ring member having an opening diameter of 15 mm or less made of an electrically insulating material;
A sample support having a stepped recess for fixing and mounting the ring member,
The sample holding stage, wherein the stepped recess is provided with an opening having an opening diameter larger than the opening diameter of the ring member. On the surface side of the sample support base having an opening, a metal sample having a flat part is placed so that the flat part is located on the surface side of the sample support base,
On the back surface side of the sample support base, an electrode facing the exposed portion at a predetermined interval is disposed at a position below the exposed portion of the flat portion of the metal sample exposed from the opening,
An emission spectroscopic analysis method that quantifies elements in the metal sample by generating a number of spark discharges in an inert gas atmosphere between the metal sample and the electrode and spectroscopically analyzing the light emission of each spark discharge. And
During spark discharge, a ring member made of an electrically insulating material for preventing discharge to a portion adjacent to the opening on the back surface of the sample support base is used, and the center line of the opening is the center line of the opening of the sample support base. Arrange to match,
An emission spectroscopic analysis method, wherein an opening diameter of a surface opening located on the surface of the sample support is 15 mm or less. The metal sample is steel having a carburized or nitrided surface.
The emission spectroscopic analysis method according to claim 5, wherein the quantitative analysis element in the metal sample is carbon or nitrogen.   The emission spectroscopic analysis method according to claim 6, wherein a discharge time of the spark discharge is set so that elemental analysis can be performed in a depth direction within 20 μm from the surface of the metal sample.

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