JPS58223047A - Method for x ray fluorescence analysis - Google Patents

Abstract

PURPOSE:To determine the thickness of a film of plated metal, wherein a substrate metal component is included in the components of the plated film, by measuring the intensity of fluorescent X rays at an angle the fluorescent X rays from the substrate metal are not detected and at an angle the X rays are detected. CONSTITUTION:X rays are irradiated from an exciting source 10 for a low angle and an exciting source 20 for a high angle over a plated metal. Fluorescent rays generated from a plated film 1 and a substrate metal 2 are converted into electric signals by detectors 11 and 12. The output of the detector 11 is inputted to a wave height analyzer 13 and a counter 14 through an amplifier 14 and converted into the intensity of the fluorescent X rays of the metal in the plated film. Meanwhile, the output of the detector 21 is inputted to a wave height analyzer 23 and a counter 24 through an amplifier 22, and converted into the intensity of the substrate metal 2. The outputs of the counter 14 and 24 are guided to an operator 30. The weight concentration and coating weight per unit area corresponding to the intensity of the fluroescent X rays are computed and displayed on a display device 31. Thus, the thickness or composition of the plated film of a Fe-Zn alloy plated steel plate can be accurately determined.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is characterized in that the base metal component is included in the components of the plating film.
The present invention relates to a method for quantifying the thickness, basis weight, and/or composition of a plating film on a plated metal, such as an Fe alloy plated steel plate, by fluorescence X@ analysis.

Fe-plated steel sheets, such as Fe-Zn plated steel sheets, which are superior in weldability, paintability, and cost efficiency, have been developed to replace conventional Ni-Zn (nickel zinc) alloy-plated steel sheets, and are used for automobile bodies. It is attracting attention as a new material.

As with conventional plated steel sheets, the quality control of the above plated steel sheets is carried out as well.
Of course, it is necessary to quantify the thickness and composition of the plating film. For materials such as Zn-plated steel sheets, in which the plating film is made of a single component other than Fe as the base metal, a method of quantifying the thickness of the plating film by fluorescent X-ray analysis has been put into practical use. That is, the fluorescent X-ray intensity of ZnKα generated from the plating film and FeKα generated from the base metal is measured, and this Fe is calculated based on the predetermined relationship (calibration curve) between the α fluorescent X-ray intensity and the plating film thickness. However, in the case of a Fe-Zn alloy plated steel sheet, the plating film consists of two components, Fe and Zn, so the fluorescent It is not easy to obtain a relationship between the thickness of the plating film and the plating film component contains Fe, which is the same as the underlying metal, so it is impossible to measure the plating film thickness using conventional fluorescent X-ray analysis. However, it was also impossible to quantify the 7C composition.

The present invention has been developed in view of the above circumstances, and its purpose is to improve the thickness and/or thickness of the plating film on plated metals, such as Fe alloy plated steel sheets, in which the base metal component is included in the components of the plating film. Alternatively, there is a point that provides a method for quantifying the composition using fluorescent X-ray analysis.

The fluorescent X-ray analysis method according to the present invention is a method for quantifying the thickness and/or composition of a plating film containing a base metal component by fluorescence X-ray analysis, in which the fluorescence X-rays from the base metal are substantially Fluorescent X-ray intensity measurement using the first excitation ray incident angle and fluorescent X-ray extraction angle that are not detected in
The present invention is characterized in that the fluorescent X-ray intensity is measured based on the second excitation ray incident angle and the fluorescent X-ray extraction angle at which the rays are detected, and the quantification is performed based on fixed positions on both sides.

The principle of the method of the present invention will be explained below. FIG. 1 is a diagram explaining the principle of the method of the present invention, in which excited X-rays are made incident at an incident angle ψ onto a Fe''Zn alloy-plated steel plate plated with Fe-Zn, which serves as the base metal. Fluorescent X-rays are taken out at an extraction angle ψ and the fluorescent X-ray intensity of Fe is measured. In this case, the difference between the fluorescent X-ray intensity of Fe and the weight concentration of Fe in the plating film is below MI"fl+ There is a relationship between formulas.

However, ■A. □: Fluorescence X-ray intensity of Fe: unit mass of analytical element Fe is excited #f fluorescence i-ca line 790 degrees
゛°□W, 8: Degree of Fe coating in the plating film (-F); Absorption coefficient (J') of the Fe-2n plating MM layer for excitation rays; Fe-Zn plating for fluorescent X-rays Turbidity absorption coefficient of the coating layer () +: Mass absorption of the base metal for excitation rays (!!-): Purchase price absorption coefficient of the entire base set for fluorescent X-rays 'Fe-Zn: Plated coating Layer density d: Plating film thickness ψ: Excitation ray incident angle ψ: Fluorescence ray extraction angle Now, if the excitation ray incidence angle ψ and the fluorescence X-ray extraction angle ψ are made smaller, the above equation (1) becomes as follows. , this relational expression: rainbow Fe fluorescence x1t#intensity I.

It can be seen that there is a unique relationship with the FQ heavy leaf concentration WFe in the plating film.
By measuring the fluorescent X-ray intensity at a low incident angle ψ and extraction angle ψ where the linear intensity is not detected, we can calculate the Fe fluorescent X-ray intensity I from the Fe weight concentration of Fe in the plating film. Find WFe.

Next, the above relationship will be clarified based on experimental results.

The sample used in the experiment was one that was electroplated in a plating solution containing Zn2+.The measurement conditions were as follows: W (tungsten) was used as the excitation source X-ray tube; Tube voltage-tube current as excitation condition is 30
The measurement time was 10 seconds at KV -39mA. Second
The figure shows Fe fluorescence
The linear strength IFoK (xCCp days) is plotted on the vertical axis, and the weight concentration of Fe in the plating film obtained by chemical analysis WF8 (%l
In this figure, the calibration curve is also shown. The values shown in this figure are FeKα Fe, which are in a positive correspondence relationship.

That has been proven.

For this device, the intensity of fluorescent X-rays from the underlying metal is detected.
When the excitation beam is completely incident at a high incident angle ψ and the fluorescent X-ray gold is extracted at an extraction angle ψ, as shown in equation (1) above, the process is affected by the thickness d of the plating film. Become. However, as mentioned above, W
When F8 is held constant, there is a unique relationship between the Fe fluorescence X-ray intensity IFeK and the plating film thickness d. Figure 3 shows the relationship between the Fe fluorescence X-ray intensity IFeK, yCcp days] measured under the conditions of high incidence angle ψ = extraction angle φ = 600 and the area weight [67 m2] obtained by chemical analysis. wFe
is shown as a variable, with I on the vertical axis and α for Fe on the horizontal axis. According to this figure, IFe.

It can be seen that there is a correspondence relationship between WFe and plating film thickness (fabric weight) d. In Fig. 3, the 0 point (solid line connection) indicates that wFe is 0% (R1) (Zn only), the X point (broken line connection) has the same <5.7 to 6.3%, and the Same (12.1-15.8%, 0 point (broken line connection) is the same < 33.5-36.7%, X point (solid line connection) is the same U
Results are shown for specimens with <44.0-47.5%. As described in detail above, the W-A obtained by low-angle fluorescent X-ray measurement. It can be seen that by measuring all the fluorescent X-ray intensities at high angles as all variables, the basis weight corresponding to the measured values can be obtained.

Next, the present invention will be specifically explained based on drawings showing its implementation state. FIG. 4 is a schematic diagram for carrying out the method of the present invention, in which X-rays are emitted from a low-angle excitation source 10 and a high-angle excitation source 2o, which are placed at appropriate positions above the plated metal. The fluorescent X-rays generated from the plating film 1 and the base metal 2 are extracted by irradiation, and the fluorescent X-rays are guided to a known detector 11, 21, etc., and the weight concentration or basis weight is measured 1.
Displayed 1. It has nine configurations. The X-rays from the excitation source 10 are irradiated onto the plating film 1 at a low incident angle ψ1, and the fluorescent X-rays extracted from the plating film l at an extraction angle ψ1 are guided to the detector 11 and converted into electrical signals. be done.

The output electric signal from the detector is input to an amplifier 12, where it is amplified and then converted into the fluorescent X-ray intensity of the metal in the plating film by a pulse height analyzer 13 and a counter 14.

On the other hand, the excitation source 2OOX rays are irradiated onto the base metal 2 at a high incident angle ψ2, and taken out from the base metal 2 at a high angle ψ.

Take out with 1. The fluorescent X-rays are at the low angle mentioned above! A detector 21. The amplifier 22 is converted into the fluorescent X-ray intensity of the base metal 2 by the wave height analyzer 23 and counter 24. The output of the counter 14.24 corresponding to the fluorescence X-ray intensity is led to the calculator 30. This arithmetic unit 30 has the relational expressions W-f(1) and FeK(r Fe
Fe FeKα I, W and basis weight (α to thickness Fθ) as shown in Fig. 3
The relational expression d=f (IFoKff, WFo) of Fe(S)d is set in advance, and the weight concentration and basis weight corresponding to the fluorescent X-ray intensity obtained as described above are calculated. 31 is displayed. As the detectors 11 and 21, it is preferable to use semiconductor detectors that can easily separate and measure the fluorescence intensities of Fe and Zrl.

Next, the results of measurements by the method of the present invention and conventional chemical analysis methods are compared to clarify the effects of the method of the present invention. WFoC%], and the horizontal axis shows WF obtained by conventional chemical analysis methods. C%)' is shown.

In FIG. 6, the vertical axis shows the basis weight Cg/m2]k obtained by fluorescent X-ray analysis using the method of the present invention, and the horizontal axis shows the basis weight Cg/m2]f obtained by the conventional chemical analysis method. As shown in Figure 5.6, the fluorescent X-ray analysis values obtained by the method of the present invention also match the chemical analysis values, and the weight concentration and basis weight of the plating film can be improved by implementing the method of the present invention. You can get the amount. In the above-mentioned embodiment, low angle and high angle measurements were performed simultaneously using two devices, but it is of course possible to perform the measurement twice using one device. Furthermore, in this example, the base metal is Fe and the plating film composition is Fe-Zn, but it goes without saying that the base metal may be a metal other than Fe, such as Cu, and the plating film may have a composition containing Cu.

As described above, when using the method of the present invention, it is possible to independently and accurately quantify the thickness or composition of the plating film of Fe-Zn alloy plated steel sheets, which are excellent in economy and weldability. Using this measurement result, it becomes possible to control the thickness of the plating film or the composition of the plating bath online, and the present invention greatly contributes to improving the quality of Fe-Zn alloy plated steel sheets. .

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the principle of the method of the present invention, and Figure 2 is
oK, z-WFo1 Figure 3 shows 'Fe with wFo as a variable.
Figure 4 is a graph showing the correlation between Ka and area weight, Figure 4 is a membrane diagram for carrying out the method of the present invention, and Figures 5 and 6 are graphs showing the relationship between Ka and area weight. It is a graph which shows the relationship between WFe and the weight of each. 10.20...Excitation source 11.21...Detector 30.
...Arithmetic unit 31...Display device patent applicant Sumitomo Metal Industries Co., Ltd. agent Patent attorney Noboru Kawano Daikiku 1 Figure 〆〆,■~Hashanbodan Gamble 6W Fe heavy 1'' Si Agricultural degree (/
, )Figure 2g +oct 〇- and) +0 211) 30
40 50th E11 < Outside/
7□Z] 3rd Fe2 4th Figure yS 5 Figure Quantity (Iotsu Scientific Analysis*>Cri A2) $6 Figure Procedure Amendment (Method) 1. Indication of Case 1982 Patent Application No. 105709 No. 2, Departure I
Name of EJ1 Fluorescence X-ray analysis power method 3, Relationship with the person making the amendment 41 cases Patent applicant 4, agent 6 Number of inventions increased by amendment 7, subject of amendment 8-1 Specification] Hosukutsu No. On page 3, line 17, the statement "Fe-Zn on r Fe" is corrected to "Fe-Zn1 on Fe2". 8-2 As shown in the attached drawing

Claims (1)

[Claims] ]-1 In the method of quantifying the thickness and/or composition of the plating film containing the base metal component by fluorescent X-ray analysis, the fluorescent X-rays from the base metal are not substantially detected. Fluorescent X-ray intensity measurement using the first excitation ray incident angle and fluorescence x151 extraction angle, and the second excitation ray incidence angle and fluorescence X-ray extraction angle at which the fluorescent X-rays from the underlying metal are detected. Fluorescent X#i! (strong) K measurement, and the quantification is carried out eight times based on constant values on both sides.