JP3937073B2 - Pretreatment method for metal analysis sample, apparatus for the same, and element analysis apparatus in metal - Google Patents

Description

【００３４】
XはA、Bの2試料について各5回づつ測定した酸素濃度の平均値であり、σはその標準偏差（ばらつき）を示す。このように本発明の実施例の場合、比較例に比べて酸素分析値は約1〜2ppm低い値を示し、分析精度も改善されている。分析に供した試料について表面解析を行ったところ、表面汚染相当分は約1〜2mmと推定され、本発明の適用によりちょうどその分の汚染が除去されたものと推定された。
【００３５】
【発明の効果】
本発明によれば、上記のように分析試料表面の汚染をスパッタリングにより除去する一連の操作を従来に比べて簡易に行うことができる。すなわち、上記特開平8-211043号公報に開示された手段のように試料台に載せられた分析試料を回転あるいは反転させる必要もなく、また、特開平11-316220号公報に開示された手段のように、分析試料を点支持するために煩雑なセット作業を伴うということもない。そのため、分析試料の予備処理に要する時間が減少し、試料１個当たりの分析時間が著しく減少する。
【図面の簡単な説明】
【図１】 本発明に係る金属分析試料の予備処理装置を備えた金属分析装置の１例を示す模式的説明図である。
【図２】 本発明における試料支持部と試料載置状態の１例を示す斜視図である。
【図３】 本発明における試料支持部と試料載置状態の他の１例を示す斜視図である。
【符号の説明】
1：予備処理室
2：（試料受けの）移動回転機構
3：試料受け
4：支持棒
7：対極
9：試料排出口
10：試料導入口
11：スライドゲート
12：試料投入口
13：反応室
S：金属分析試料[0001]
BACKGROUND OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal analysis sample pretreatment method and apparatus, and more particularly to a metal analysis sample pretreatment method for removing contaminants adhering and adsorbing to a sample surface in advance of analyzing trace elements in the metal. The present invention also relates to an apparatus for analyzing elements in metals using the apparatus.
[0002]
[Prior art]
Trace elements in steel, such as oxygen, carbon, nitrogen, and sulfur, affect material properties such as ductility and workability of steel, so accurate quantitative analysis is necessary. This has been widely pointed out not only for steel but also for metal materials in general as the purity of metal materials is increased, and therefore, there is a need for an analysis apparatus and analysis method with high accuracy and good operability.
[0003]
In order to meet such requirements, it is necessary to improve the accuracy of the analysis means and to remove contamination generated on the sample surface in the adjustment stage of the metal analysis sample. For example, in oxygen analysis in steel, if there is an adsorbed organic substance on the sample surface, or if there is surface oxidation due to an atmosphere such as carbon dioxide or air, a significant error will be caused in the analysis value. Therefore, in the inert gas melting-infrared absorption method widely used as a method for analyzing trace oxygen in metals, the surface of a metal analysis sample is treated and cleaned by electrolytic polishing or chemical polishing prior to analysis. It has been broken.
[0004]
However, even if the surface contamination is removed by such a method, cleaning chemical species and polishing chemical species associated with cleaning and polishing remain, or the sample surface is recontaminated by the air before measurement with an analyzer. Or reoxidation may occur. Due to these causes, significant errors occur in the quantitative analysis performed with the accuracy of ppm level (iron and steel vol.85, p.138 (1999), etc.). In particular, a clean metal surface is susceptible to atmospheric adsorption and oxidation, and removal of the recontaminated part is important for improving analysis accuracy.
[0005]
For this reason, a method is disclosed in which the surface contamination is removed by sputtering the surface of a metal analysis sample by discharge in a low-pressure gas, and the carbon analysis is carried out by transferring it directly to an analyzer (Japanese Patent Laid-Open No. 8-211043). Publication). In addition, after fixing the analysis sample with point support in the pretreatment chamber for removing the surface contamination of the analysis sample and removing the surface contamination portion by sputtering under an inert gas atmosphere, the pretreatment chamber, the reaction chamber, A method is disclosed in which a shutter is separated and a metal analysis sample is dropped into a reaction chamber, whereby the analysis target after processing is not exposed to the atmosphere (Japanese Patent Laid-Open No. 11-316220). .
[0006]
[Problems to be solved by the invention]
However, in the means disclosed in the above Japanese Patent Laid-Open No. 8-211043, since the metal analysis sample is placed on the sample stage during the sputtering process, the back surface (contact surface of the sample with the sample stage) is In order to clean it, it is necessary to rotate or reverse the metal analysis sample, which is not only complicated, but also the metal analysis sample may fall off the sample stage, making analysis impossible.
[0007]
The means disclosed in Japanese Patent Application Laid-Open No. 11-316220 can simultaneously perform decontamination treatment on almost the entire surface of the analysis sample. However, since this method provides point support for a metal analysis sample, there remains a problem relating to operability, which involves difficulty in setting the analysis sample.
[0008]
The present invention aims to solve the above-mentioned problems of the prior art, and provides an easy-to-operate means for removing contamination on the surface of a sample when analyzing a trace component in a metal. It is an object of the present invention to provide an analysis apparatus for elements in metals that are used.
[0009]
[Means for Solving the Problems]
The present invention provides a metal analysis sample pretreatment method in which the surface of a metal analysis sample is cleaned by sputtering in a pretreatment chamber maintained in an inert gas atmosphere prior to analysis of the components in the metal. The above-mentioned problem is solved by performing sputtering while supporting from the bottom side by a sample receiver with a very small contact area ratio with respect to the analysis sample.
[0010]
In the above-mentioned invention, it is desirable that the inert gas atmosphere for performing sputtering is pressure adjusted to 100 Pa or more and 1000 Pa or less, and the metal analysis sample contact area of the sample receiver is 10% or less of the surface area of the metal analysis sample. Is desirable.
[0011]
The metal analysis sample pretreatment apparatus of the present invention has a sample loading inlet that can be opened and closed at the top, a sample introduction port that can be opened and closed that communicates with the reaction chamber at the bottom, and a pretreatment chamber that has a gas inlet and an outlet. A sample receiver that is supported by a support rod that penetrates at least one side wall of the pretreatment chamber and is capable of horizontal movement and axial rotation, and maintains the sample at a predetermined potential in a state where the ratio of the contact area to the metal analysis sample is extremely small; And a counter electrode having a polarity opposite to that of the sample receiver and the sample, and arranged in a region that does not hinder the introduction of the sample into the pretreatment chamber and the introduction of the sample into the reaction chamber.
[0012]
It is preferable that the apparatus includes an analysis sample support moving mechanism that sends the support rod of the sample receiver together with the sample receiver and the metal analysis sample mounted thereon directly above the openable and closable inlet. The sample contact area of the sample receiver is preferably 10% or less of the surface area of the metal analysis sample.
[0013]
The metal element analysis apparatus of the present invention uses the metal analysis sample pretreatment apparatus.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings of examples according to the present invention.
[0015]
In the present invention, for example, the surface of a metal analysis sample is cleaned by sputtering in a pretreatment chamber maintained in an inert gas atmosphere prior to analysis of components in the metal as disclosed in JP-A-11-316220. It is applied to a pretreatment method for metal analysis samples. The greatest feature of the present invention is that the method for supporting the metal analysis sample is improved so that the metal analysis sample is supported from the bottom surface side, and the contact area of the support member with the metal analysis sample is as much as possible. This is in that a sample receiver with a smaller structure is adopted.
[0016]
FIG. 1 is a schematic explanatory view showing an example of a pretreatment apparatus for a metal analysis sample according to the present invention. As shown here, in the present invention, similarly to the example disclosed in Japanese Patent Application Laid-Open No. 11-316220, which is a conventional example, the metal analysis sample S has a surface contaminated portion in the pretreatment chamber 1 whose sputtering is performed. And then guided into the reaction chamber 13 of the metal element analyzer.
[0017]
Here, the pretreatment chamber 1 has a body shape as a whole. For example, a main body made of ceramics is provided with an inert gas inlet and an exhaust port. The pretreatment chamber 1 has a sample inlet 12 at the upper part and a sample outlet 9 at the lower part. The sample discharge port 9 is connected to a sample introduction port 10 that communicates with the reaction chamber 13 of the metal element analyzer main body through a slide gate 11 capable of maintaining confidentiality.
[0018]
A sample receiver 3 is arranged inside the preliminary processing chamber 1, and this sample receiver 3 is connected to the analysis sample support part moving and rotating mechanism 2 via a support rod 4 penetrating the side wall of the preliminary processing chamber 1. linked. As a result, the metal analysis sample S can be put in and out (horizontal direction) in a state where the metal analysis sample S is placed on the sample receiver 3, and can be inverted at a predetermined position by rotating the shaft to be dropped from the sample receiver. The sample receiver 3 also serves as an electrode for setting the metal analysis sample S to one polarity. Therefore, the support bar 4 is one electrode (not shown) of a power source (not shown) that generates a high voltage, for example, 1 KV. Connected to the cathode).
[0019]
A metal sample S and a counter electrode 7 electrically facing the sample receiver 3 on which the metal sample S is placed are installed at a position where the sample receiver on which the metal analysis sample S is placed can enter and exit. The counter electrode 7 is connected to a high-voltage power source in the same manner as the support bar 4, and its polarity is opposite to that of the support bar (in this case, the anode). Thus, after evacuating the inside of the pretreatment chamber 1, if an inert gas, for example, argon gas, is introduced at a predetermined pressure and a voltage is applied between the sample support portion and the counter electrode, the surface of the metal analysis sample S The contamination is removed by sputtering.
[0020]
The counter electrode 7 is placed in a region that does not hinder the introduction of the sample into the pretreatment chamber 1 and the introduction of the sample into the reaction chamber 13. Specifically, as shown in FIG. 1, the installation position of the counter electrode 7 is usually separated from the vertical area of the sample inlet in an area excluding the area within the vertical line surrounding the inlet 12 and the outlet 9. It is good to arrange at the position. However, even if the counter electrode 7 protrudes from the region in the vertical line surrounding the sample inlet 12 and the outlet 9, the implementation of the present invention will not be hindered unless the sample is charged and discharged.
[0021]
In the example shown in FIG. 1, the counter electrode 7 is installed above and below the sample receiver on which the metal analysis sample S is placed. However, the present invention is not limited to this. Depending on the shape of the sample, it can also be arranged facing left and right or diagonally. In addition, it is also possible to arrange at an asymmetrical position with respect to the sample. Further, the counter electrode can be formed into a cylindrical shape, and thereby, cleaning can be performed uniformly and efficiently from the periphery of the sample. The shape of the counter electrode can be freely set as long as it does not deviate from the purpose, and for example, a rectangular tube shape can also be used. Also, the number of counter electrodes is not particularly limited.
[0022]
In the present invention, the metal analysis sample S is supported by, for example, two rod-shaped sample receivers 3 as shown in FIG. As a result, the metal analysis sample S is supported in a state where the contact area with the bottom surface of the metal analysis sample S is extremely small while being placed on the sample support portion 3. As a result, not only the top and side surfaces of the metal analysis sample S but also the bottom surface side is sputtered except for a slight contact portion with the support portion 3. That is, the entire surface of the metal analysis sample S can be simultaneously subjected to the decontamination process. In addition, since the sample is simply placed on the support portion 3, the handling is simple.
[0023]
Such functions include supporting the sample support 3 from the bottom side of the metal analysis sample S, and sputtering ions (for example, argon gas ions) from the counter electrode 7 to the metal on the bottom side of the metal analysis sample S. This can be achieved by ensuring a sufficient gap for high-speed collision with the bottom surface side of the analysis sample S. For this purpose, the sample support unit 3 is required to support the metal analysis sample S from the bottom side in a state where the ratio of the contact area with the sample is extremely small.
[0024]
As a specific shape of the sample receiver that satisfies such requirements, there are two rod-like bodies shown in FIG. 2, but for example, a wire mesh-like one may be used as shown in FIG. In addition, it is only necessary that the contact area with the metal analysis sample S is small, such as a square or circular frame, and the gap is wide as viewed from the counter electrode 7. Note that the contact area between the metal analysis sample S and the sample support portion 3 affects the removal rate of the surface contaminated portion, and hence the analysis error, so it is preferable to design the contact area so as to be as small as possible. In general, it is sufficient if the ratio of the contact area of the sample receiver to the sample surface area is 10% or less. More preferably, the bottom area of the metal analysis sample is 5% or less, more preferably 3% or less.
[0025]
Note that these sample receivers 3 keep the metal analysis sample S at a constant polarity during the surface contamination removal by sputtering, so that the electrical conductivity must be excellent, and the sputtering treatment It must be free from gas and other pollutants generated by heat. In that sense, for example, it is preferable to use 18-8 stainless steel.
[0026]
In the pretreatment apparatus of the present invention, the sample receiver 3 is preferably configured to be movable forward, backward, and rotatable within the pretreatment chamber 1. In the example shown in FIG. 1, a sample receiver 3 is connected to a moving and rotating mechanism 2 via a support rod 4, and this moving and rotating mechanism 2 attaches the sample support part 3 to the preliminary processing chamber 1 by a known means such as a motor or a cylinder. Within, make it forward, backward and rotatable.
[0027]
By doing so, the surface contamination removal (sputtering) of the metal analysis sample S can be efficiently performed in a relatively narrow space surrounded by the counter electrode 7. Further, after the sputtering is finished, the metal analysis sample S is moved into the reaction chamber 13 by advancing and rotating the sample receiver 3 in the pretreatment chamber 1 to the position immediately above the sample introduction port 10 below the pretreatment chamber 1. Can be dropped.
[0028]
In order to pre-process a metal analysis sample using the metal analysis sample pre-processing apparatus configured as described above, first, the sample receiver 3 is moved to a position immediately below the sample inlet 12, and the metal analysis sample S is loaded. Drop it on it. Next, after closing the charging port 12 and the slide gate 11 and evacuating the processing chamber 1, an inert gas, for example, argon gas is introduced, and the pressure is adjusted to 100 to 1000 Pa. Thereby, the cleaning by sputtering is performed efficiently and reliably.
[0029]
Next, the sample receiver 3 is moved horizontally between the counter electrodes 7 in a state where the metal analysis sample S is placed. In this state, a voltage is applied to the sample receiver 3 and the counter electrode 7, and the surface of the metal analysis sample S is cleaned by sputtering.
[0030]
The metal analysis sample whose surface is cleaned is dropped into the elemental analyzer. Specifically, the sample holder on which the cleaned metal analysis sample is placed is horizontally moved to above the sample outlet 9 by the moving rotation mechanism 2, and this is moved and rotated with the slide gate 11 opened. The metal analysis sample S is inverted by the mechanism 2 and dropped into the elemental analysis device through the sample introduction port 10.
[0031]
Thus, according to the present invention, surface contamination due to sputtering of a metal analysis sample can be efficiently removed with good operability. The present invention can be applied regardless of the type of metal to be analyzed, and can also be applied regardless of the type of element to be analyzed or the analysis method. Furthermore, it is not restrict | limited also to the polarity and kind for performing sputtering. In the example shown in FIG. 1, the analysis sample side is a cathode, but this may be an anode, and the type of sputtering may be changed to arc sputtering. Furthermore, the analysis sample support part, the counter electrode, etc. and their surroundings can be directly or indirectly cooled by an appropriate refrigerant.
[0032]
【Example】
A steel sample having a diameter of 6 mm and a length of 5 mm was used as a metal analysis sample, and oxygen in the sample was quantified by a melting-infrared absorption method in an inert gas. The results are shown in Table 1. The examples in Table 1 are the results of oxygen analysis after the pretreatment by the pretreatment apparatus of the present invention shown in FIG. On the other hand, the comparative example is a result of performing oxygen analysis directly without performing pretreatment.
[0033]
[Table 1]

[0034]
X is the average value of the oxygen concentration measured 5 times for each of the two samples A and B, and σ indicates the standard deviation (variation). Thus, in the example of the present invention, the oxygen analysis value is about 1 to 2 ppm lower than the comparative example, and the analysis accuracy is also improved. When the surface analysis was performed on the sample subjected to the analysis, the surface contamination equivalent was estimated to be about 1 to 2 mm, and it was estimated that the contamination was just removed by the application of the present invention.
[0035]
【The invention's effect】
According to the present invention, as described above, a series of operations for removing contamination on the surface of an analysis sample by sputtering can be easily performed as compared with the conventional case. That is, there is no need to rotate or reverse the analysis sample placed on the sample stage as in the means disclosed in the above-mentioned JP-A-8-211043, and the means disclosed in JP-A-11-316220 As described above, there is no complicated setting work for point-supporting the analysis sample. For this reason, the time required for preprocessing the analysis sample is reduced, and the analysis time per sample is significantly reduced.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory view showing an example of a metal analyzer equipped with a pretreatment apparatus for a metal analysis sample according to the present invention.
FIG. 2 is a perspective view showing an example of a sample support portion and a sample mounting state in the present invention.
FIG. 3 is a perspective view showing another example of a sample support portion and a sample mounting state in the present invention.
[Explanation of symbols]
1: Pretreatment chamber
2: Moving rotation mechanism (of sample holder)
3: Sample receiver
4: Support rod
7: Counter electrode
9: Sample outlet
10: Sample inlet
11: Slide gate
12: Sample inlet
13: Reaction chamber
S: Metal analysis sample

Claims (7)

In a pretreatment method of a metal analysis sample, the surface of the metal analysis sample is cleaned by sputtering in a pretreatment chamber maintained in an inert gas atmosphere prior to analysis of the components in the metal.
A pretreatment method for a metal analysis sample, characterized in that the metal analysis sample is sputtered while being supported from the bottom side by a sample receiver having a very small contact area ratio with respect to the metal analysis sample. 2. The pretreatment method for a metal analysis sample according to claim 1, wherein the pressure of the inert gas atmosphere is adjusted to 100 Pa or more and 1000 Pa or less. The metal analysis sample pretreatment method according to claim 1 or 2, wherein the metal analysis sample contact area of the sample receiver is 10% or less of the surface area of the metal analysis sample. A sample loading inlet that can be opened and closed at the top, a sample processing inlet that can be opened and closed that communicates with the reaction chamber of the metal sample analyzer main body at the bottom, and a pretreatment chamber having a gas inlet and a gas outlet.
A sample receiver that is supported by a support rod that passes through at least one side wall of the pretreatment chamber and is capable of horizontal movement and axial rotation, and maintains the sample at a predetermined potential in a state in which the ratio of the contact area to the metal analysis sample is extremely small; and A metal having a polarity opposite to that of the sample receiver and the sample, and a counter electrode disposed in a region that does not hinder the introduction of the sample into the pretreatment chamber and the introduction of the sample into the reaction chamber Analytical sample pretreatment equipment. 5. The preliminary analysis of a metal analysis sample according to claim 4, wherein the support bar includes a moving mechanism for moving an analysis sample supporting portion that sends the sample receiver together with the metal analysis sample directly above the openable / closable sample discharge port. Processing equipment. 6. The pretreatment apparatus for a metal analysis sample according to claim 5, wherein the metal analysis sample contact area of the sample receiver is 10% or less of the surface area of the metal analysis sample. The elemental analyzer in the metal which comprises the metal analyzer in any one of Claims 4-6.

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