CN116538985A - Surface treatment layer thickness measurement method - Google Patents

Abstract

The invention discloses a method for measuring the thickness of a surface treatment layer, which comprises the following steps: obtaining standard normal distribution curves corresponding to different metal elements in standard samples of surface treatment layers with different thicknesses, wherein the normal distribution curves are relationship curves between element content and probability density of a certain element at a certain thickness; obtaining a sample normal distribution curve corresponding to each metal element of a sample to be detected; and obtaining the thickness value of the surface treatment layer calculated based on different metal elements of the sample to be measured one by one according to the standard normal distribution curve corresponding to each metal element under different standard thicknesses and the sample normal distribution curve corresponding to the corresponding metal element of the sample to be measured, so as to obtain the thickness of the surface treatment layer of the sample to be measured. The method can realize the rapid and nondestructive measurement of the thickness of the surface treatment layer, is not limited by a measurement area, has no too much limitation on the materials of the substrate of the sample to be measured and the surface treatment layer, and has wide applicability.

Description

Surface treatment layer thickness measurement method

technical field

The invention belongs to the technical field of measurement, and in particular relates to a method for measuring the thickness of a surface treatment layer.

Background technique

In the existing surface treatment layer measurement technology, measurement methods such as magnetic thickness measurement, eddy current thickness measurement, and spiral micrometer thickness measurement are usually used, but these methods have certain limitations in actual measurement; for example, the magnetic thickness measurement method requires substrate or The surface treatment layer is magnetic; the eddy current thickness measurement method requires the substrate and the surface treatment layer to have electrical conductivity; the use of a spiral micrometer is only suitable for thickness measurement in the boundary area of the substrate, and cannot measure the surface treatment layer in the middle area.

Contents of the invention

The purpose of the present invention is to provide a method for measuring the thickness of the surface treatment layer, which solves the problems of limited applicability and poor versatility of existing measurement methods.

The present invention realizes through following technical scheme:

The method for measuring the thickness of the surface treatment layer comprises the following steps:

S01. Obtain the standard normal distribution curve corresponding to each different metal element in the standard sample of the surface treatment layer with different thicknesses, the normal distribution curve is the relationship between the element content and the probability density of a certain element under a certain thickness curve;

S02. Obtain the sample normal distribution curve corresponding to each metal element of the sample to be tested;

S03. According to the standard normal distribution curve corresponding to each metal element under different standard thicknesses and the sample normal distribution curve corresponding to the corresponding metal element of the sample to be tested, the thickness of the surface treatment layer calculated based on the different metal elements of the sample to be tested is obtained one by one. value to obtain the thickness of the surface treatment layer of the sample to be tested.

As a further improvement of the above technical solution, step S01 includes:

S011, preparing standard samples with surface treatment layers of different thicknesses;

S012, measuring the thickness of the surface treatment layer of the standard sample;

S013, performing multiple measurements on the metal element content in the standard sample with different thicknesses, and obtaining the standard normal distribution curves corresponding to the different metal elements in the surface treatment layer with different thicknesses.

As a further improvement of the above technical solution, standard normal distribution curves corresponding to all metal elements with a content of not less than 0.1% in the standard sample are obtained.

As a further improvement of the above technical solution, in step S012, a magnetic thickness gauge, an eddy current thickness gauge, and a screw micrometer are used to measure the surface treatment thickness of the specified area on the standard sample multiple times to obtain the surface treatment layer thickness of the standard sample.

As a further improvement of the above technical solution, the designated area is the position where the metal element content in the standard sample is measured in step S013.

As a further improvement of the above technical solution, the metal element content in the sample to be tested is measured multiple times to obtain the normal distribution curve of the sample corresponding to each metal element in the sample to be tested.

As a further improvement of the above technical solution, the normal distribution curve of the sample corresponding to all the metal elements whose content is not less than 0.1% in the sample to be tested is obtained.

As a further improvement of the above technical solution, the test equipment, test method, and test parameters used to measure the metal element content in the sample to be tested are the same as the test conditions for the standard sample.

As a further improvement of the above technical solution, step S03 includes:

S031, fitting the standard normal distribution curve corresponding to a certain metal element under each different standard thickness with the sample normal distribution curve corresponding to the metal element of the sample to be tested;

S032. Obtain two standard normal distribution curves adjacent to both sides of the normal distribution curve of the sample, and obtain the metal by the metal according to the overlap area or mean distance or intersection point between the normal distribution curve of the sample and the two standard normal distribution curves. The thickness value of the surface treatment layer calculated by the element;

S033. Process the thickness values of each surface treatment layer obtained in step S032 to obtain the thickness of the surface treatment layer of the sample to be tested.

As a further improvement of the above technical solution, in step S032, the thickness value of the surface treatment layer is calculated according to a certain metal element, including:

Obtain the coincidence area ratio between the sample normal distribution curve and two standard normal distribution curves, the coincidence area ratio between the standard normal distribution curve and the sample normal distribution curve and the corresponding standard normal distribution curve area ratio;

When the overlapping area ratio of the normal distribution curve of the sample and the two standard normal distribution curves is not less than 5%, the thickness of the surface treatment layer corresponding to the calculation of the metal element is:

Among them, A is the standard thickness value corresponding to the standard normal distribution curve on the left side, B is the standard thickness value corresponding to the standard normal distribution curve on the right side, n ₁ % is the overlapping area ratio corresponding to the standard normal distribution curve on the left side, n ₂ % is the overlap area ratio corresponding to the standard normal distribution curve on the right;

When the overlapping area ratio of the normal distribution curve of the sample and the two standard normal distribution curves is less than 5%, the calculated thickness of the surface treatment layer corresponding to the metal element is:

Among them, N is the average value of the element content of the sample to be tested, N ₁ is the average value of the element content corresponding to the left standard normal distribution curve, N ₂ is the average value of the element content corresponding to the right standard normal distribution curve value;

When the overlap area ratio of the normal distribution curve of the sample and two standard normal distribution curves is not less than 5% on one side and less than 5% on the other side, the surface treatment obtained by corresponding calculation of the metal element The layer thickness is:

Obtain the intersection point between the standard normal distribution curve corresponding to the side where the overlapping area ratio is not less than 5% and the sample normal distribution curve and the metal element content corresponding to the intersection point. According to the corresponding metal element content in the metal element content and the surface The corresponding thickness value obtained from the standard curve of the treatment layer thickness is the thickness of the surface treatment layer calculated correspondingly from the metal element.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

The present invention establishes a standard database for thickness measurement based on the relationship between various elements and thickness of the substrate of the surface treatment layer with a standard thickness, and realizes the measurement of the thickness of the surface treatment layer by measuring the elements of the sample to be measured. The rapid and non-destructive measurement of the thickness of the surface treatment layer is not limited by the measurement area, and there are not too many restrictions on the materials of the substrate of the sample to be tested and the surface treatment layer, and has wide applicability.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be viewed The scope is limited, and those skilled in the art can also obtain other related drawings based on these drawings without creative work.

Fig. 1 is the standard sample prepared in the embodiment of the measuring method of the present invention.

Fig. 2 is a standard normal distribution curve corresponding to Fe elements in standard samples with different thicknesses in the embodiment of the measurement method of the present invention.

Fig. 3 is a sample normal distribution curve corresponding to the Fe element of the sample to be tested in the embodiment of the measurement method of the present invention.

Fig. 4 is a schematic diagram of a situation of fitting the standard normal distribution curve and the sample normal distribution curve in the embodiment of the measurement method of the present invention.

Fig. 5 is a schematic diagram of another situation of fitting the standard normal distribution curve and the sample normal distribution curve in the embodiment of the measurement method of the present invention.

Fig. 6 is a schematic diagram of another situation of fitting the standard normal distribution curve and the sample normal distribution curve in the embodiment of the measurement method of the present invention.

Fig. 7 is a standard corresponding curve of Fe element content and surface treatment layer thickness.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments.

The present invention establishes a standard database for thickness measurement based on the relationship between various elements and thickness of the substrate of the surface treatment layer with a standard thickness, and realizes the measurement of the thickness of the surface treatment layer by measuring the elements of the sample to be measured. The rapid and non-destructive measurement of the thickness of the surface treatment layer will not be limited by the measurement area. There is no restriction on the substrate of the sample to be tested and the material of the surface treatment layer. It can be measured by this method only if it contains metal elements.

In one embodiment, the method for measuring the thickness of the surface treatment layer includes the following steps:

S01. Perform surface treatment on the surface of known metal matrix materials according to the normal product manufacturing process, and prepare multiple standard samples with different surface treatment layers; the thickness of the surface treatment layer in standard samples is generally not less than 5um, and the thickness of each standard sample The thickness of the surface treatment shall generally cover the upper and lower thickness values for the required test thickness. Generally, part of the area on the standard sample should be reserved without surface treatment to identify the metal substrate material.

Clean the surface treatment layer of the standard sample, and measure the thickness of the surface treatment layer. Standard measuring tools can be used for measurement, such as magnetic thickness gauge, eddy current thickness gauge, screw micrometer and other instruments can be used for measurement. The specified area of the standard sample is measured by repeated multi-point measurement. The specified area is usually the area where metal elements are measured, and the standard average and standard deviation of the thickness measurement values are calculated. The number of measurements should not be less than 7 times/point. If the measurement data fluctuates greatly, the number of measurements should be increased.

The X-ray fluorescence spectrometer is used to measure standard samples with different surface treatment layer thicknesses, and multiple measurements are made in designated areas to measure the content of metal elements. Record the measured values of all metal elements with content ≥0.1%, and calculate their standard mean and standard deviation respectively.

Based on the thickness of the surface treatment layer of the standard sample obtained by the above measurement and the measured values of the different metal elements of the corresponding standard samples, the standard normal distribution curve corresponding to each different metal element in the standard sample of the surface treatment layer with different thicknesses is established. In the state distribution curve, the abscissa is the element percentage content, and the ordinate is the probability density of the measured value, forming a standard database corresponding to different metal elements in standard samples corresponding to different thickness surface treatment layers. The probability density here refers to the number of times corresponding to the same measured value when multiple measurements are made.

S02. Measure the metal element content of the sample to be tested. The test equipment, test mode and test process parameters used for the measurement are exactly the same as those used for the standard sample. The number of measurements is generally not less than 5 times/point, and the recorded content is ≥ 0.1% of the measured values of all metal elements, and calculate their standard mean and standard deviation respectively.

The sample normal distribution curve corresponding to each metal element of the sample to be tested is obtained based on the measured value.

S03. According to the standard normal distribution curve corresponding to each metal element under different standard thicknesses and the sample normal distribution curve corresponding to the corresponding metal element of the sample to be tested, the thickness of the surface treatment layer calculated based on the different metal elements of the sample to be tested is obtained one by one. value to obtain the thickness of the surface treatment layer of the sample to be tested.

In this step, the standard normal distribution curve corresponding to a certain metal element under each different standard thickness is fitted with the sample normal distribution curve of the corresponding metal element of the sample to be tested; Two standard normal distribution curves, according to the coincidence area or mean distance or intersection point position between the sample normal distribution curve and the two standard normal distribution curves, the surface treatment layer thickness value calculated by the metal element is obtained; The obtained thickness values of each surface treatment layer are processed to obtain the thickness of the surface treatment layer of the sample to be tested.

The measuring method of the present invention will be further described below in conjunction with specific examples.

1) Perform surface treatment (D.Cd) on the surface of the known metal substrate (30CrMnSiA) according to the normal product manufacturing process, and obtain 3 standard samples with thickness ranges of 5-12um, 12-18um, and 18-25um. The back of the sample is not subjected to surface treatment, and is used for subsequent component testing of the metal matrix; the prepared standard sample is shown in Figure 1.

2) Use acetone to wipe and clean the surface of the standard sample to remove surface pollutants that may affect the analysis, use a coating thickness gauge to perform multiple repeated multi-point thickness measurements on the designated area of the standard sample, and calculate the measured standard mean and standard deviation.

Among them, the formula for calculating the standard average value is:

x _i is the ith measured value;

The formula for calculating the standard deviation is:

3) Use the X-MET7500 X-ray fluorescence analyzer, select the measurement mode as Alloy LE Mode and the test process parameters (conventional focus test) to measure the metal element content of the standard sample, and the number of measurements is 8 times/point. Record the measured values of metal elements such as Fe, Cr, Mn, Cd, Co and other elements with a content of ≥0.1% in the substrate with a surface treatment layer, and calculate their standard average and standard deviation.

4) Use Minitab software to draw the standard normal distribution curve corresponding to the above-mentioned metal elements of the standard sample, as shown in Figure 2, it is the normal distribution curve corresponding to the Fe element corresponding to the surface treatment layer with different thicknesses, and the abscissa in the curve is the element percentage content , and the ordinate is the probability density of measured values, forming a standard database corresponding to different metal elements in standard samples corresponding to surface treatment layers with different thicknesses.

5) Measure the metal element content of the sample to be tested. The test equipment, test mode and test process parameters used in the measurement are exactly the same as those used in the measurement of the standard sample. The number of measurements is 8 times/point, and the metal elements such as Fe, The measured values of Cr, Mn, Cd, Co and other elements, and calculate their standard average and standard deviation.

6) Adopt the Minitab software to draw the sample normal distribution curve corresponding to each metal element of the test sample, as shown in Figure 3, it is the normal distribution curve of the Fe element content corresponding to the test sample, the abscissa is the element percentage content in the same curve, and the ordinate is Measures the probability density of a value.

7) Fit the sample normal distribution curve of each element of the sample to be tested with the standard normal distribution curve of each element of the standard sample with different thicknesses, and fit them into the same coordinate system to form the sample normal distribution curve corresponding to different elements and The set of standard normal distribution curves, as shown in Figure 4, is the case where the sample normal distribution curve and standard normal distribution curve corresponding to the Fe element are fitted to the same coordinate system;

Select two standard normal distribution curves adjacent to both sides of the sample normal distribution curve for analysis, as shown in Figure 4, calculate the coincidence of the coincidence area between the sample normal distribution curve and the selected two standard normal distribution curves Area ratio or average spacing, to obtain the calculated thickness of the surface treatment layer corresponding to the metal element. Specifically, the calculation method used is as follows:

Taking Fe element as an example, calculate the overlap area ratio between its corresponding sample normal distribution curve and two standard normal distribution curves.

When the overlap area ratio of the normal distribution curve of the sample and the two standard normal distribution curves is not less than 5%, as shown in Figure 4, the thickness of the surface treatment layer corresponding to the metal element is calculated according to the overlap area ratio. The formula is:

Among them, A is the standard thickness value corresponding to the standard normal distribution curve on the left side, B is the standard thickness value corresponding to the standard normal distribution curve on the right side, n ₁ % is the overlapping area ratio corresponding to the standard normal distribution curve on the left side, n ₂ % is the overlap area ratio corresponding to the standard normal distribution curve on the right.

When the overlapping area ratio of the normal distribution curve of the sample and the two standard normal distribution curves is less than 5%, as shown in Figure 5, the thickness of the surface treatment layer corresponding to the metal element is calculated according to the mean distance, and the calculation formula is:

Among them, N is the average value of the element content of the sample to be tested, N ₁ is the average value of the element content corresponding to the left standard normal distribution curve, N ₂ is the average value of the element content corresponding to the right standard normal distribution curve value.

When the overlapping area ratio of the normal distribution curve of the sample and the two standard normal distribution curves, the overlapping area ratio of one side is not less than 5%, and the other side is less than 5%, as shown in Figure 6, the corresponding calculation of the metal element is obtained The thickness of the surface treatment layer is:

Obtain the intersection point (point A in Figure 6) between the standard normal distribution curve and the sample normal distribution curve corresponding to the side where the overlapping area ratio is not less than 5%, and the Fe element content value corresponding to the intersection point in the coordinate system, As shown in Figure 6, the content of Fe element corresponding to point A is 36%;

Then on the Fe element content and surface treatment layer thickness standard corresponding curve (as shown in Figure 7), obtain the Fe element content corresponding to point A on the Fe element content curve, then draw a vertical line with the point of the corresponding position on the Fe element content curve vertical line, the intersection point (point B) of the vertical line and the thickness curve is obtained, and the thickness value corresponding to point B (taking Figure 7 as an example, the thickness value corresponding to point B is 10 μm) is the corresponding calculation by Fe element The obtained surface treatment layer thickness.

The standard corresponding curve between the metal element content and the thickness of the surface treatment layer is a curve drawn based on the data of the metal element content values corresponding to the surface treatment layer with different standard thicknesses obtained through detection. Taking Fe element as an example, as shown in the table below, for measurement The data corresponding to the obtained Fe element content and the thickness of the surface treatment layer:

Based on the data table obtained from the above measurements, a biaxial graph is drawn, as shown in Figure 7, where the left side of the ordinate corresponds to the Fe element content, and the right side of the ordinate corresponds to the thickness of the surface treatment layer. Only part of the measurement data is given in the above table. In actual operation, the amount of measurement data will be large, and the more measurement data, the smoother the drawn curve.

8) Repeat step 7) to obtain the surface treatment layer thickness value calculated corresponding to other elements, based on the surface treatment layer thickness value Ti calculated above, calculate the surface treatment layer thickness of the sample to be tested, the calculation formula is:

At this point, the thickness of the surface treatment layer of the sample to be tested can be obtained.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Any simple modifications and equivalent changes made to the above embodiments according to the technical essence of the present invention all fall within the scope of the present invention. within the scope of protection.

Claims (10)

1. The surface treatment layer thickness measurement method is characterized in that, comprising the following steps: S01. Obtain the standard normal distribution curve corresponding to each different metal element in the standard sample of the surface treatment layer with different thicknesses, the normal distribution curve is the relationship between the element content and the probability density of a certain element under a certain thickness curve; S02. Obtain the sample normal distribution curve corresponding to each metal element of the sample to be tested; S03. According to the standard normal distribution curve corresponding to each metal element under different standard thicknesses and the sample normal distribution curve corresponding to the corresponding metal element of the sample to be tested, the thickness of the surface treatment layer calculated based on the different metal elements of the sample to be tested is obtained one by one. value to obtain the thickness of the surface treatment layer of the sample to be tested. 2. The surface treatment layer thickness measuring method according to claim 1, characterized in that, step S01 comprises: S011, preparing standard samples with surface treatment layers of different thicknesses; S012, measuring the thickness of the surface treatment layer of the standard sample; S013, performing multiple measurements on the metal element content in the standard sample with different thicknesses, and obtaining the standard normal distribution curves corresponding to the different metal elements in the surface treatment layer with different thicknesses. 3. The method for measuring the thickness of the surface treatment layer according to claim 1 or 2, characterized in that the standard normal distribution curves corresponding to all metal elements with content not less than 0.1% in the standard sample are obtained. 4. The surface treatment layer thickness measuring method according to claim 2, wherein in step S012, a magnetic thickness gauge, an eddy current thickness gauge, and a screw micrometer are used to perform multiple times on the surface treatment thickness of the designated area on the standard sample. Measure to obtain the thickness of the surface treatment layer of the standard sample. 5 . The method for measuring the thickness of the surface treatment layer according to claim 4 , wherein the specified area is the position where the metal element content in the standard sample is measured in step S013 . 6. The method for measuring the thickness of the surface treatment layer according to claim 1, wherein the metal element content in the sample to be tested is measured multiple times to obtain a sample normal distribution curve corresponding to each metal element of the sample to be tested. 7. The method for measuring the thickness of the surface treatment layer according to claim 1 or 6, characterized in that the sample normal distribution curves corresponding to all metal elements whose content is not less than 0.1% in the sample to be tested are obtained. 8. The surface treatment layer thickness measuring method according to claim 6, characterized in that, the test equipment, test method, test parameters and test conditions for testing the standard sample are measured for the metal element content in the sample to be tested same. 9. The surface treatment layer thickness measurement method according to claim 1, characterized in that, step S03 comprises: S031, fitting the standard normal distribution curve corresponding to a certain metal element under each different standard thickness with the sample normal distribution curve corresponding to the metal element of the sample to be tested; S032. Obtain two standard normal distribution curves adjacent to both sides of the normal distribution curve of the sample, and obtain the metal by the metal according to the overlap area or mean distance or intersection point between the normal distribution curve of the sample and the two standard normal distribution curves. The thickness value of the surface treatment layer calculated by the element; S033. Process the thickness values of each surface treatment layer obtained in step S032 to obtain the thickness of the surface treatment layer of the sample to be tested. 10. The method for measuring the thickness of the surface treatment layer according to claim 9, wherein the calculation of the thickness value of the surface treatment layer according to a certain metal element in step S032 includes: Obtain the coincidence area ratio between the sample normal distribution curve and two standard normal distribution curves, the coincidence area ratio between the standard normal distribution curve and the sample normal distribution curve and the corresponding standard normal distribution curve area ratio; When the overlapping area ratio of the normal distribution curve of the sample and the two standard normal distribution curves is not less than 5%, the thickness of the surface treatment layer corresponding to the calculation of the metal element is: Among them, A is the standard thickness value corresponding to the standard normal distribution curve on the left side, B is the standard thickness value corresponding to the standard normal distribution curve on the right side, n ₁ % is the overlapping area ratio corresponding to the standard normal distribution curve on the left side, n ₂ % is the overlap area ratio corresponding to the standard normal distribution curve on the right; When the overlapping area ratio of the normal distribution curve of the sample and the two standard normal distribution curves is less than 5%, the calculated thickness of the surface treatment layer corresponding to the metal element is: Among them, N is the average value of the element content of the sample to be tested, N ₁ is the average value of the element content corresponding to the left standard normal distribution curve, N ₂ is the average value of the element content corresponding to the right standard normal distribution curve value; When the overlap area ratio of the normal distribution curve of the sample and two standard normal distribution curves is not less than 5% on one side and less than 5% on the other side, the surface treatment obtained by corresponding calculation of the metal element The layer thickness is: Obtain the intersection point between the standard normal distribution curve corresponding to the side where the overlapping area ratio is not less than 5% and the sample normal distribution curve and the metal element content corresponding to the intersection point. According to the corresponding metal element content in the metal element content and the surface The corresponding thickness value obtained from the standard curve of the treatment layer thickness is the thickness of the surface treatment layer calculated correspondingly from the metal element.