JP3369011B2 - Quantitative analysis method of weight composition ratio of element in depth direction of metal material in glow discharge emission spectroscopy - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the determination of the weight composition ratio of elements in the depth direction in glow discharge optical emission spectroscopy used for analyzing the surface of a metal material. It relates to the analysis method. In particular, materials such as hot rolling rolls used in the manufacture of steel materials, in which carbides and metal matrix are dispersed inhomogeneously, and coatings such as oxide films with different conductivity and luminescent properties from the base material are applied to the surface. The formed material,
The present invention relates to a method for quantitatively analyzing the weight composition ratio of elements in the depth direction when glow discharge emission spectroscopy is performed simultaneously and continuously on a coating and a base material. 2. Description of the Related Art Glow discharge emission spectroscopy is one of surface analysis methods for detecting elements emitted (emitted) from the surface of a material by sputtering using an inert gas. In this analysis method, an inert gas (such as an argon gas) is ionized to collide with the surface of the material, and the emission intensity of the element emitted (emitted) (sputtered) from the surface is set for each element. Measurement for a certain period of time by the dedicated detector. Then, the relationship between the weight composition ratio of each element and the depth from the surface is analyzed using the obtained emission intensity using a certain method. The following methods are known as means for quantitatively analyzing the weight composition ratio of elements in the depth direction in the glow discharge emission spectroscopy at this time. First,
Using a standard sample, the emission yield of each element required to convert the emission intensity measured by glow discharge emission spectroscopy into the weight composition ratio and the depth of the element is determined. Quantitative analysis methods for calculating the weight composition ratio of elements in the depth direction for various materials by using the same are well known (“Quantitative analysis of oxide film depth by glow discharge emission spectroscopy”). : Iron and Steel, Vol. 77, (1991), p25
3). [0003] However, in the conventional quantitative analysis method of the weight composition ratio of the elements in the depth direction, the light emission characteristics of a material measured using glow discharge are different from those of a standard sample. If it is the same as above, accurate quantitative analysis of the weight composition ratio of the element in the depth direction is possible, but accurate quantitative analysis different from the emission characteristics of the standard sample cannot be performed. In addition, the luminescent characteristics of the material often differ greatly depending on the length of the gap between the material and the anode electrode of the device, the cleanliness of the surface, the composition, and the like. In particular, in the case of a material in which a carbide and a metal matrix are heterogeneously dispersed, such as a hot-rolling roll used in a steel manufacturing process, the light emission characteristics may be significantly different even with the same composition. In addition, in a roll having an oxide film called black scale formed on the surface, the light emission characteristics of the black scale and the base material are significantly different. The composition and porosity of the black scale change depending on the conditions under which the black scale is formed. Therefore, it is difficult to accurately analyze the weight composition ratio of the element in the depth direction of such a material by the conventional method of obtaining and analyzing the luminescence yield in advance. On the other hand, there is a method of preparing a sample for cross-sectional observation and performing quantitative analysis in the depth direction by cross-sectional observation. However, it is necessary to cut out an expensive material such as a roll material each time.
This leads to an increase in analysis costs and R & D costs, making efficient experiments difficult. In order to analyze materials such as the above-mentioned hot rolls by glow discharge optical emission spectroscopy, a highly accurate quantitative analysis method of the weight composition ratio of elements in the depth direction in consideration of the difference in the light emission characteristics of the materials is required. is necessary. According to the present invention, the accuracy of glow discharge emission spectroscopy is improved by using the emission yield determined in advance and correcting the emission yield for each measurement in accordance with the difference in the emission characteristics of the materials. To provide a method for quantitative analysis of the weight composition ratio of elements in the depth direction with a high density. SUMMARY OF THE INVENTION The present invention provides a method for glow discharge optical emission spectroscopy, in which the luminous yield of each element is reduced when quantitative analysis of the weight composition ratio of the element in the depth direction of the metal material is performed. R
_n [(Volt / kg) · m ² · sec], the depth of the sputtering mark obtained by quantitative analysis of the composition weight ratio of the element in the depth direction using the luminescence yield R _n is d _a [μm], When the actually measured depth of the sputtering mark is _dr [μm], equation (1)
Correction emission yield obtained by R _n '[(Volt / kg) · m
² · sec], and quantitative analysis of the weight composition ratio of the element in the depth direction is performed again. To improve the _{R n '= R n · (} d r / d a) ......... (1) [0007] [action] Quantitative analysis accuracy of the weight composition ratio of the depth direction in the glow discharge optical emission spectroscopy element Is
It is important to accurately determine the coefficient of luminous yield for analyzing the measured luminous intensity and the weight composition ratio according to the material. In the conventional analysis method, a standard sample having substantially the same composition and a known composition is prepared before measurement, and the luminescence yield is determined in advance. The emission intensity of the standard sample is measured by glow discharge emission spectroscopy. Next, by measuring the weight loss of the dent (sputtering trace) of the measurement part formed by the emission (emission) of the element, and dividing by the measurement time (sputtering time) and the area of the dent of the measurement part, a unit is obtained. The weight loss of the material per time and unit area (referred to as mass sputtering rate) is determined. Then, the luminous yield of each element is determined by equation (2) from the luminous intensity of each element, the weight ratio of the material composition, and the mass sputtering rate. Then, in the subsequent quantitative analysis, the quantitative analysis of the weight composition ratio of the element in the depth direction is performed using the emission yield obtained here. R _n = I _n / V _m · C _n (2) where V _m [kg / (m ² · sec)] is a mass sputtering rate, C _n is a material composition ratio [−], I _n [ [Volt] is the emission intensity, and R _n [(Volt / kg) · m ² · sec] is the emission yield of element n. Next, when a quantitative analysis of the weight composition ratio of the element in the depth direction is performed by the conventional method using the light emission yield, t + Δt [se] from a certain time t [sec] based on the measured light emission intensity.
Equation (3) is used to determine the composition ratio ΔC _n [−] of the element n in the part removed by sputtering during c], and Equation (4) is used to determine the depth Δd [μm] of the part. Is used. [0010] Here, I _n '[Volt] emission intensity of a standard sample when the determined light emission yield, C _n' [-] is the weight composition ratio of the element n of the standard sample, V _m '[kg / (m ² .Sec)] is the mass sputtering rate at that time. When calculating the weight composition ratio of the element from the equation (3), since there is no term of the mass sputtering rate in the equation (3), even if the mass sputtering rate is different between the time of obtaining the emission yield and the time of the actual measurement. (Even if the emission characteristics differ between the standard sample and the actual measurement material), it is understood that it does not affect the quantitative analysis result of the weight composition ratio of the element. However, when the depth of the pit formed by removing the material by light emission is obtained from Equation (4), if the mass sputtering rate is different between when the luminescence yield is obtained and when the actual measurement is performed, the accurate depth is obtained. No quantitative analysis results can be obtained. Therefore, in order to accurately perform the quantitative analysis of the weight composition ratio of the elements in the depth direction, it is necessary to use the luminescence yield corrected according to the luminescence characteristics of the measurement material instead of using the luminescence yield determined in advance. Must. According to the present invention, the luminescence yield (R _n [(Volt / kg) · m ² · sec]) previously determined for a standard sample is corrected in accordance with the luminescence characteristics of the material to be measured, and a highly accurate depth is obtained. A method for performing quantitative analysis in the vertical direction has been devised. That is, the luminescence intensity (I _n [Volt]) of the material is measured, and the luminescence yield (R _n
[(Volt / kg) · m ² · sec]) and the depth (d _a [μm]) of the sputtering trace quantitatively analyzed using the depth of the hollow part (depth of the sputtering trace) actually formed in the material. is) the surface roughness meter measured the sputtering mark depth or the like (d _r as [μm]) and match, (d _r
/ D _a ) multiplied by the luminescence yield (R _n ) to obtain the corrected luminescence yield (R
_n ′ [(Volt / kg) · m ² · sec]), and the weight composition ratio of the element in the depth direction from the luminescence intensity (I _n ) measured again using the corrected luminescence yield (R _n ′). We considered a method of quantitative analysis of. In _{R n '= R n · (} d r / d a) ......... (1) wherein, (R _n ^{[(Volt / kg) · m 2} · sec ]) is luminous yield obtained in advance using the standard sample Rate, d _a [μm] is the calculated value of the depth of the sputtering mark obtained using the luminescence yield R _n , and d _r [μm] is the actually measured depth of the sputtering mark, R _n ′ [(Volt / kg ) · M ² · sec] is the corrected luminescence yield. In the present invention, the weight composition ratio of the element in the depth direction is analyzed again by the equations (3) and (4) using R _n 'defined by the equation (1). When this method is used, even if the emission characteristics of the standard sample and the material to be actually measured are different, the difference in the emission yield is corrected by Equation (1), and the emission yield according to the emission characteristics of the material is increased in the depth direction. Quantitative analysis of the weight composition ratio of the elements can be accurately performed. In the case of a material having an oxide film formed on a surface layer such as a hot-rolled roll, when the oxide composition of the surface layer and the roll base material are simultaneously and continuously analyzed quantitatively for the weight composition ratio of elements in the depth direction, the oxidation Since the light emission characteristics differ between the film and the base material,
Essentially, the oxide film and the base material must be quantitatively analyzed using different luminescence yields. However, the oxide film of the hot-rolled roll is usually composed of a plurality of oxides, and its composition ratio varies depending on the friction conditions when it is formed. That is, since the light emission characteristics of the oxide film vary depending on the conditions under which the oxide film is formed, it is difficult to obtain the light emission yield of such an oxide film in advance. However, using the method of the present invention, even if the luminescence yield of the black scale is unknown, the value of the luminescence yield is corrected so that the actually measured depth of the sputtering trace matches the depth of the sputtering trace by analysis. In addition, since a luminescence yield applicable to black scale is obtained, accurate quantitative analysis of the weight composition ratio of elements in the depth direction is possible. EXAMPLES Using a hot-rolled roll material, quantitative analysis of the element weight composition ratio in the depth direction was performed by glow discharge emission spectroscopy. Table 1 shows the chemical composition of the hot-rolled roll material. [Table 1] Samples of the hot-rolled roll material are shown in Table 1,
Two types of B were prepared. Sample A had no oxide film called black scale, and sample B had black scale. As for the sample B having the black scale, the sample was cut, the cross section was observed, and the thickness of the black scale was measured.
m. When an oxide constituting black scale was examined by X-ray diffraction analysis, it was mainly Fe ₃ O ₄ . These two samples were used to compare the results of quantitative analysis between the conventional method and the method of the present invention. Sputtering time is 60
0 seconds, emission voltage 200 V, argon gas 2 min / min
The measurement was performed while flowing 00 cc. However, with respect to the sample having black scales, the measurement was performed with the sputtering time set to 100 seconds. The sample A was used as a standard sample, and the luminescence yield (R _n ) used in the conventional method was obtained from the measurement result of the luminescence intensity of this sample using the equation (2). However, since the luminescence yield of oxygen cannot be determined from the standard sample, the luminescence yield of iron and oxygen (R _n ) was obtained from the quantitative analysis result of the sample B with black scale with a sputtering time of 100 seconds. I asked. Sputtering time is 10
The reason for setting the time to 0 second is that when the sputtering time is 100 seconds, the depth of the sputtering mark is smaller than the thickness of the black scale and does not reach the base material. This is because the rate can be obtained. Table 2 shows the obtained values of the luminescence yield. [Table 2] Next, using the luminescence yield (Table 2) obtained from the standard sample (sample A), quantitative analysis of the weight composition ratio of elements in the depth direction of sample B where black scale was present was carried out. From the measurement results of the luminescence intensity when the sputtering time is set to 600 seconds, the results of quantitative analysis of the weight composition ratio of the elements in the depth direction by the conventional method using Equations (3) and (4) are shown. It is shown in FIG. After the measurement, the depth of the sample sputtering mark was measured with a surface shape measuring device.
It was 2.0 μm. According to the quantitative analysis result of the weight composition ratio according to the conventional method shown in FIG.
This is 6.5 μm, which is largely different from the depth of the sputtering mark of 12.0 μm obtained by the actual measurement. Also,
The depth of the interface between the base material and the black scale (black film thickness) was found to be about 13 μm from the profiles of iron and oxygen, which was completely different from the actually measured 6.3 μm, and the weight composition ratio of the elements in the depth direction was accurate. I do not know. Therefore, the method of the present invention is used for sample B. Quantitative analysis was performed to determine the corrected luminescence yield using equation (1). The corrected luminescence yield (R _n ′) at that time is shown in Table 3, and using the obtained corrected luminescence yield, the formula (3),
FIG. 2 shows the weight composition ratio of the element in the depth direction obtained by (4). [Table 3] The depth of the sputtering mark obtained by the quantitative analysis and the depth of the sputtering mark measured by the surface shape measuring device were in good agreement. The depth (black film thickness) of the interface between the base material and the black scale is calculated from the profiles of iron and oxygen, and is about 6.5.
μm, which almost coincided with the actually measured value of 6.3 μm. In addition, the weight composition ratio of the base material region of each element substantially coincides with the chemical composition of the sample shown in Table 1, and quantitative analysis with higher precision in the depth direction than the conventional method is possible. By using the present invention, a high-precision quantitative analysis of the weight composition ratio of elements in the depth direction, which has been difficult with the conventional method, has become possible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows the results of the weight composition ratio of elements in the depth direction, which was quantitatively analyzed by a conventional method using a roll material without black scale as a standard sample and by a luminescence yield according to a conventional method. FIG. 2 is a result of a weight composition ratio of elements in a depth direction obtained by quantitatively analyzing a roll material having a black scale by a method according to the present invention.

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Shigeru Suzuki 20-1 Shintomi, Futtsu-shi, Chiba Nippon Steel Corporation Technology Development Division (56) References JP-A-60-179633 (JP, A) JP-A-60-185143 (JP, A) JP-A-3-176646 (JP, A) JP-A-6-18418 (JP, A) JP-A-6-117998 (JP, A) (58) Int.Cl. ⁷ , DB name) G01N 21/62-21/74 G01N 33/20 JICST file (JOIS)

Claims (1)

(57) [Claims 1] When performing quantitative analysis of the weight composition ratio of elements in the depth direction of a metal material using glow discharge emission spectroscopy, the luminescence yield of each element To R _n [(Volt / kg) · m ²
· Sec], emission yield using R _n quantitative analysis obtained in sputtering mark depth weight composition ratio of each element d _a [μ
m], and when the actually measured depth of the sputtering mark is _dr [μm], the corrected luminescence yield R _n ′ obtained by R _n ′ = R _n · (d _r / d _a ) (1) (Volt / kg) ・ m
² · sec], wherein the weight composition ratio of the element in the depth direction is analyzed again, and the quantitative analysis method of the weight composition ratio of the element in the depth direction of the metal material in glow discharge emission spectroscopy.