JPS60179633A - Method for analyzing quantitatively layer state sample by emission spectrochemical analysis - Google Patents

Abstract

PURPOSE:To make the quantitative analysis in the depth direction of a sample surface possible, by recording the variation with time of the emission intensity of each element, obtaining the evaporated quantity of each element from the area of the characteristic curve of the emission intensity, and obtaining the distribution of each element in the depth direction based on the vaporized quantity. CONSTITUTION:In emission spectrochemical analysis of a sample processed by multilayer plating, etc. by glow discharge, the variation in the emission intensity with time of each element is recorded. The vaporized quantity of each element is obtained based on the calibration curve between the area of the emission intensity curve and the evaporated quantity of each element relating the reference sample prepared previously, from the area of the characteristic curve of the emission intensity. The ratio of each element is calculated from the evaporated quantity to obtain the distribution of each element in the depth direction. Thereby, the quantitative analysis of each element in the depth direction becomes possible.

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention is an analytical method for measuring the amount of adhesion of multilayer plating, etc. by optical emission spectrometry, in which the analysis proceeds in the depth direction while removing the sample surface using glow discharge. Regarding.

- Conventional technology The optical emission spectrometry method uses the sample as the cathode of a glow discharge tube and uses cathode sputtering to scrape the sample surface while emitting light from the evaporated sample atoms by glow discharge.The method is characterized by the ability to analyze changes in composition in the depth direction of the sample surface. However, until now only qualitative analysis was possible. For example, when analyzing galvanized steel,
Initially, the luminescence of zinc is strong and the luminescence of iron is weak, but as time passes, the luminescence of iron becomes stronger and the luminescence of zinc becomes weaker. This is because the zinc plating layer gradually evaporates and the iron base comes out, but by recording the temporal changes in the luminescence intensity of each element,
If we could simply convert the emission intensity axis into elemental concentration and the time axis into depth from the sample surface, quantitative analysis would be possible, but we cannot find an appropriate operation to convert both axes into elemental concentration and depth. , quantitative analysis was not possible.

C. Purpose The present invention provides a method for calculating element concentration and depth from luminescence intensity and time, and aims to enable quantitative analysis in the depth direction of a sample surface using glow discharge emission spectrometry.

2. Configuration Now suppose that we have obtained a time record of luminescence intensity as shown in Figure 1. In this figure, A indicates the luminescence intensity of the element B, and B indicates the luminescence intensity of the B element. This result qualitatively shows that the surface of the sample is covered with element B, that there is a mixed layer of both elements, and that the underlying layer is element B. The area of the shaded part in this figure is related to the amount of evaporation of element A between times tl and t2.

Furthermore, the luminescence intensity is related to the evaporation rate of the element at that point. A similar relationship holds true for element B as well.

Therefore, if the area between times t1 and t2 of the luminescence intensity curve is generally S, then the amount of element evaporation W within this time is W - f
It can be written as (S). Determine the shape of f (S) using a standard sample. In Figure 1, the area of the luminescence intensity curve of element B during tl)t2 time is Sa, and the area of element B is s.
b, and the area functions of the respective evaporation amounts are fa(S) and fb
(S), from this function A, B between tl and t2
The amount of evaporation of both elements is equal. Assuming that these are Wa and Wb, the composition of the exposed sample surface during times t1 and t≧ is A
Element W a / (W a, + W b ) B element Wb/(Wa+Wb). If the specific gravity of the alloy with this composition is g and the sample area is σ, then (W , a + W b )/gσ, and therefore the depth d of the sample surface cut between times t′l and t2 is reduced. By performing this operation by appropriately dividing the time width from the point of time 0 in Figure 1, the composition ratio and abrasion depth for each section can be determined, and the A in the depth direction as shown in Figure 2, A graph showing changes in the composition ratio of both elements B can be drawn.

E. Implementation/Example Approximate the form of the function f in the form as3+b8"+cs+d,
The coefficients a, b, c, and d are determined for each element using standard samples.

Figure 3 shows the analysis results of a sample coated with three layers of plating.

Qualitative analysis shows that the first layer is Cr plated and the second layer is F plated.
e, Zn alloy plating, third layer is Ni.

The base material is thought to be lre with Zn alloy plating.

Therefore, each coefficient of the function is determined for each of these elements. In Figure 3, Cr is chromium, Fe is iron, Zn is zinc,
N1 is the luminescence intensity curve of nickel. In the figure, the arrows at the ear opening and ``no'' indicate chrome and iron, respectively.

At the half-width point of each curve of zinc, considering that this point is the boundary of each layer, from time 0 to tl4 and from tl to t2
Until then, the area of each emission intensity curve in each time period from t2 to t3-1 was calculated, the amount of evaporation of each element in each layer was calculated, and then converted to the composition change of each element in the thickness direction. This is shown in Figure 4.

In the embodiments described above, the form of the function f (S) is expressed as a third-order polynomial, but the form of this equation can be arbitrary, and if it is expressed in this form, the program of the calculation by the computer becomes easier. Furthermore, in the above embodiment, the evaporation amount is determined by determining the functional form between the area of the emission intensity curve and the evaporation amount, and the depth of the layer is calculated from the evaporation amount. The relationship with the evaporation rate W is determined in advance, the composition is determined from the evaporation rate at each time point, the specific gravity is calculated from the composition, the abrasion speed of the sample surface at each time point is determined, and the composition change in the depth direction is determined. It is also possible to draw

In glow discharge emission spectroscopy, the evaporation rate of the same element varies considerably depending on the plating conditions, and therefore the luminescence intensity also varies. For this reason, the emitted light intensity cannot be said to be the content of the element, and since the evaporation rate is different, the elapsed time does not correspond uniquely to the distance in the depth direction. The reason why the emission intensity is strong and the duration is short is because there are many elements and the layer thickness is thin.
The fact that the light emission is weak and the duration is long does not mean that the element is small and the layer thickness is thick. On the one hand, the evaporation rate is fast;
On the other hand, the evaporation rate is slow.

In the present invention, since the amount of evaporation is calculated by the area of the emission intensity curve, quantitative analysis in the depth direction of the sample surface is possible without being affected by variations in the evaporation rate.

[Brief explanation of the drawing]

FIG. 1 is a detailed graph explaining the present invention. FIG. 2 is a graph explaining the results obtained by the present invention. FIG. 3 is a graph of an analysis example in which the method of the present invention was carried out.
It is a graph which shows the result of analyzing the analysis result of a figure by the method of this invention. Agent Patent Attorney Kosuke Agata

Claims (1)

[Claims] In optical emission spectrometry, the analysis proceeds in the depth direction of the sample surface while volatilizing the sample surface with a glow discharge tube that uses the sample as a cathode. The relationship between the intensity and the evaporation rate of the element at that time or the area of the luminescence light curve and the amount of evaporation of that element is determined in advance using a standard sample, and this is used to determine the specific gravity of the substance of each element in the sample and the total element. A quantitative analysis method for a layered sample using emission spectroscopy, characterized in that the amount of abrasion on the sample surface is calculated from the total amount of evaporation, and the distribution of each element in the depth direction is determined.