Method for non-destructive detection of the oxygen index of a wave-absorbing material

Abstract

This invention relates to the field of microwave absorbing material testing technology, specifically to a non-destructive method for detecting the oxygen index of microwave absorbing materials. The method involves measuring the levels of aluminum, phosphorus, and carbon at different locations on the bottom cross-section of the microwave absorbing material using an elemental analyzer, obtaining spectra; calculating the ratio of the peak integral area of ​​aluminum and phosphorus to that of carbon; and combining different oxygen index and ratio curves to evaluate the oxygen index at different locations on the bottom of the microwave absorbing material. This non-destructive testing of the oxygen index of microwave absorbing materials allows for the non-destructive, efficient, and rapid screening of products with different oxygen indices, facilitating the detection of oxygen index in microwave absorbing materials.

Description

Technical Field

[0001] This invention relates to the field of microwave absorbing material testing technology, and in particular to a non-destructive method for testing the oxygen index of microwave absorbing materials. Background Technology

[0002] Microwave absorbing materials for anechoic chambers are a type of carbon-impregnated flexible polyurethane absorbing material. These materials possess excellent absorption performance and good flame retardant properties. As the input power of the device under test increases exponentially, high demands are placed on the flame retardancy of the absorbing material. In the actual production process of absorbing materials, flame retardant performance testing is an essential step. Among these tests, the oxygen index test is used to evaluate the flame resistance of the absorbing material.

[0003] Currently, oxygen index testing involves random sampling of products after production. The test results only represent the range of oxygen index values ​​for the sampled products and cannot comprehensively and accurately assess the oxygen index of each individual product. Furthermore, oxygen index testing is a destructive test; each sampling test results in the product being cut and damaged, rendering it unusable for shipment. The more samples tested, the more wasted products there are, which is detrimental to the oxygen index detection of microwave absorbing materials. Summary of the Invention

[0004] The purpose of this invention is to provide a non-destructive method for detecting the oxygen index of microwave absorbing materials, aiming to solve the technical problem that each sampling test in the prior art leads to product cutting and damage, which is not conducive to the detection of the oxygen index of microwave absorbing materials.

[0005] To achieve the above objectives, the present invention employs a non-destructive method for detecting the oxygen index of microwave absorbing materials, comprising the following steps:

[0006] The elemental analysis instrument was used to measure the aluminum, phosphorus, and carbon elements at different locations on the bottom cross-section of the microwave absorbing material to obtain the spectrum.

[0007] Calculate the ratio of the integrated peak area of ​​aluminum and phosphorus to the integrated peak area of ​​carbon in the tested microwave absorbing material.

[0008] By combining different oxygen index and ratio curves, the oxygen index at different locations on the bottom of the tested microwave absorbing material is evaluated, thus achieving non-destructive testing of the oxygen index of the microwave absorbing material.

[0009] Before the step of measuring the levels of aluminum, phosphorus, and carbon at different locations on the bottom cross-section of the absorbing material using an elemental analyzer to obtain the spectrum:

[0010] By using an oxygen index meter, microwave absorbing materials with different oxygen index values ​​were tested. By using an elemental analyzer, the elemental spectrum of the microwave absorbing materials was measured, and the integral area of ​​the aluminum, phosphorus, and carbon peaks of the microwave absorbing materials was calculated.

[0011] The sum of the peak areas of aluminum and phosphorus is calculated, and then the sum of the peak areas is divided by the peak area of ​​carbon to obtain the ratio of the integral area of ​​aluminum and phosphorus peaks to the integral area of ​​carbon peak.

[0012] Plot the oxygen index values ​​on the ordinate and the ratio of the integral area of ​​aluminum and phosphorus peaks to the integral area of ​​carbon peak on the abscissa. Obtain curves for different oxygen indices using curve fitting.

[0013] In the step of evaluating the oxygen index at different locations on the bottom of the tested microwave absorbing material by combining different oxygen indices and ratio curves, and thus achieving non-destructive testing of the oxygen index of the microwave absorbing material, the process of obtaining different oxygen indices and ratio curves is as follows:

[0014] The oxygen index values ​​of some microwave absorbing sheets were obtained by measuring some microwave absorbing sheets with an oxygen index meter. Elemental analysis tests were performed on the microwave absorbing sheets to calculate the ratio of the peak integral area of ​​aluminum and phosphorus to the peak integral area of ​​carbon in the microwave absorbing sheets.

[0015] Plotting the oxygen index on the ordinate and the ratio on the abscissa, and fitting the curves, we obtain curves for different oxygen indices and ratios.

[0016] Among them, the step of evaluating the oxygen index at different locations on the bottom of the tested microwave absorbing material by combining different oxygen index and ratio curves, thus achieving non-destructive testing of the oxygen index of the microwave absorbing material:

[0017] The oxygen index value of the tested microwave absorbing material is determined by the ratio and the corresponding ratio curves for different oxygen indices.

[0018] This invention discloses a non-destructive method for detecting the oxygen index of microwave absorbing materials. The method involves measuring the levels of aluminum, phosphorus, and carbon at different locations on the bottom cross-section of the microwave absorbing material using an elemental analyzer, obtaining spectra. The ratio of the peak integral area of ​​aluminum and phosphorus to that of carbon is calculated. By combining different oxygen index and ratio curves, the oxygen index at different locations on the bottom of the microwave absorbing material is evaluated, achieving non-destructive testing of the oxygen index of the absorbing material. This method can non-destructively, efficiently, and rapidly separate products with different oxygen indices, which is beneficial for oxygen index detection of microwave absorbing materials. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a flowchart of the steps of the non-destructive method for detecting the oxygen index of microwave absorbing materials according to the present invention.

[0021] Figure 2 This is a graph showing the ratios of different oxygen indices in Example 1 of the present invention. Detailed Implementation

[0022] Please see Figure 1 ,in Figure 1 This is a flowchart illustrating the steps of a non-destructive method for detecting the oxygen index of microwave absorbing materials. The present invention provides a non-destructive method for detecting the oxygen index of microwave absorbing materials, comprising the following steps:

[0023] S1: Using an oxygen index meter, microwave absorbing materials with different oxygen index values ​​are tested. The elemental spectrum of the microwave absorbing materials is measured using an elemental analyzer, and the integral area of ​​the aluminum, phosphorus, and carbon peaks of the microwave absorbing materials is calculated.

[0024] S2: Calculate the total peak area of ​​aluminum and phosphorus elements, divide the total area by the peak area of ​​carbon element, and obtain the integral area ratio of aluminum and phosphorus peaks to the integral area ratio of carbon peak.

[0025] S3: Plot a graph with the oxygen index value on the ordinate and the ratio of the integral area of ​​aluminum and phosphorus peaks to the integral area of ​​carbon peak on the abscissa. Obtain curves for different oxygen indices by curve fitting.

[0026] S4: The aluminum, phosphorus and carbon elements at different locations on the bottom cross-section of the absorbing material are measured using an elemental analyzer to obtain the spectrum.

[0027] S5: Calculate the ratio of the integrated area of ​​aluminum and phosphorus peaks to the integrated area of ​​carbon peaks in the tested absorbing material;

[0028] S6: Measure the oxygen index of the absorbing sheet using an oxygen index meter, perform elemental analysis on the absorbing sheet, and calculate the ratio of the peak integral area of ​​aluminum and phosphorus to the peak integral area of ​​carbon in the absorbing sheet.

[0029] S7: Plot the oxygen index on the ordinate and the ratio on the abscissa, and fit the curve to obtain curves for different oxygen indices and ratios.

[0030] S8: By using the ratio and combining different oxygen indices with the ratio curve, the oxygen index at different locations on the bottom of the tested microwave absorbing material is evaluated, and the oxygen index value of the tested microwave absorbing material is determined, thus realizing non-destructive testing of the oxygen index of the microwave absorbing material.

[0031] In this embodiment, firstly, an oxygen index meter is used to test the microwave absorbing materials with different oxygen index values. Then, an elemental analyzer is used to measure the elemental spectrum of the microwave absorbing materials. The integrated areas of the aluminum, phosphorus, and carbon peaks are calculated. The total area of ​​the aluminum and phosphorus peaks is then calculated, and divided by the carbon peak area to obtain the ratio of the integrated area of ​​the aluminum and phosphorus peaks to the integrated area of ​​the carbon peak. A graph is plotted with the oxygen index value as the ordinate and the ratio of the integrated area of ​​the aluminum and phosphorus peaks to the integrated area of ​​the carbon peak as the abscissa. Curve fitting is used to obtain curves corresponding to different oxygen indices. Finally, the elemental analyzer is used to measure the aluminum, phosphorus, and carbon elements at different locations on the bottom cross-section of the microwave absorbing material to obtain the resulting spectra. The method calculates the ratio of the peak integrated area of ​​aluminum and phosphorus to that of carbon in the tested microwave absorbing material. The oxygen index of the absorbing sheet is then measured using an oxygen index meter. Elemental analysis is performed on the absorbing sheet to calculate the ratio of the peak integrated area of ​​aluminum and phosphorus to that of carbon. A graph is then plotted with the oxygen index as the ordinate and the ratio as the abscissa. A fitting curve is obtained to obtain curves showing different oxygen indices and ratios. Finally, by combining the ratio with the different oxygen index and ratio curves, the oxygen index at different locations on the bottom of the tested microwave absorbing material is evaluated, and the oxygen index value of the tested microwave absorbing material is determined. This method achieves non-destructive testing of the oxygen index of absorbing materials, enabling the non-damaging, efficient, and rapid screening of products with different oxygen indices, which is beneficial for oxygen index detection of absorbing materials.

[0032] Example 1

[0033] Please see Figure 2 ,in Figure 2 This is a curve graph showing the ratios corresponding to different oxygen indices in Example 1. A sample was taken from the bottom of the absorbing material, and the oxygen index of the sampled portion was measured to be 28.3% using an oxygen index meter. Elemental analysis was performed on the sampled portion with an oxygen index of 28.3%, and a spectrum was obtained. The integrated areas of the aluminum, phosphorus, and carbon peaks in this sample were calculated using spectrum analysis software. The total area of ​​the aluminum and phosphorus peaks was calculated, and then divided by the carbon peak area, resulting in a ratio of 0.8 between the integrated areas of the aluminum and phosphorus peaks and the carbon peak. This process was repeated, resulting in a ratio of 0.75 for a sample with an oxygen index of 27.8%, 0.88 for a sample with an oxygen index of 30.3%, 0.92 for a sample with an oxygen index of 31.2%, 0.95 for a sample with an oxygen index of 32.1%, and 1.1 for a sample with an oxygen index of 33.3%. Curves showing the ratios corresponding to different oxygen indices were plotted, as shown below. Figure 2As shown; then the dried microwave absorbing material is repaired, and a handheld elemental analyzer is used to test different positions on the bottom of the microwave absorbing material. The integrated areas of the peaks of aluminum, phosphorus and carbon are recorded, and the ratios are calculated. The oxygen index of different positions of the repaired microwave absorbing material is obtained through a curve graph. The oxygen index value and fluctuation range of this microwave absorbing material are then obtained by averaging the values, thus completing the oxygen index test of the non-destructive microwave absorbing material.

[0034] The above description discloses only one preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A non-destructive method for detecting the oxygen index of microwave absorbing materials, characterized in that, Includes the following steps: Microwave absorbing materials with different oxygen index values ​​were tested using an oxygen index meter. The elemental analyzer was used to measure the aluminum, phosphorus, and carbon elements at different locations on the bottom cross-section of the microwave absorbing material to obtain the spectrum. The ratio of the integrated area of ​​aluminum and phosphorus peaks to the integrated area of ​​carbon peaks in the tested microwave absorbing material is calculated. The oxygen index value is plotted on the vertical axis, and the ratio of the integrated area of ​​aluminum and phosphorus peaks to the integrated area of ​​carbon peaks is plotted on the horizontal axis. The curves corresponding to different oxygen indices are obtained. By combining different oxygen index and ratio curves, the oxygen index at different locations on the bottom of the tested microwave absorbing material is evaluated, thus achieving non-destructive testing of the oxygen index of the microwave absorbing material.

2. The method for non-destructive testing of the oxygen index of microwave absorbing materials as described in claim 1, characterized in that, Before the step of measuring the levels of aluminum, phosphorus, and carbon at different locations on the bottom cross-section of the absorbing material using an elemental analyzer to obtain the spectrum: By using an oxygen index meter, microwave absorbing materials with different oxygen index values ​​were tested. The elemental spectrum of the microwave absorbing materials was measured by an elemental analyzer, and the integral area of ​​the aluminum, phosphorus, and carbon peaks of the microwave absorbing materials was calculated. The sum of the peak areas of aluminum and phosphorus is calculated, and then divided by the peak area of ​​carbon to obtain the ratio of the integral area of ​​aluminum and phosphorus peaks to the integral area of ​​carbon peak.

3. The method for non-destructive testing of the oxygen index of microwave absorbing materials as described in claim 2, characterized in that, In the process of evaluating the oxygen index at different locations on the bottom of the tested microwave absorbing material by combining different oxygen indices and ratio curves, and achieving non-destructive testing of the oxygen index of the microwave absorbing material, the process of obtaining different oxygen indices and ratio curves is as follows: The oxygen index values ​​of some microwave absorbing sheets were obtained by measuring some microwave absorbing sheets with an oxygen index meter. Elemental analysis tests were performed on the microwave absorbing sheets to calculate the ratio of the peak integral area of ​​aluminum and phosphorus to the peak integral area of ​​carbon in the microwave absorbing sheets. Plotting the oxygen index on the ordinate and the ratio on the abscissa, and fitting the curves, we obtain curves for different oxygen indices and ratios.

4. The method for non-destructive testing of the oxygen index of microwave absorbing materials as described in claim 3, characterized in that, In the process of evaluating the oxygen index at different locations on the bottom of the tested microwave absorbing material by combining different oxygen index and ratio curves, the following steps are taken to achieve non-destructive testing of the oxygen index of the microwave absorbing material: The oxygen index value of the tested microwave absorbing material is determined by the ratio and the corresponding ratio curves for different oxygen indices.

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