Method for determining the integral porosity of a local region of a thin metal layer on a flat substrate

Abstract

FIELD: porosimetry.SUBSTANCE: method for determining the integral porosity of a local region of a thin metal layer on a flat substrate includes determining the ratio of the pore volume to the geometric volume of the selected region and calculating the porosity of the material in it. The test sample is a thin metal layer of arbitrary shape with a thickness of 1 to 50 μm, applied to a flat metal substrate. To isolate the local area being studied in a thin metal layer, a foil mask with a round hole is applied to its surface. Using an optical profilograph, a profilogram of the surface profile of a flat metal substrate and the surface profile of a thin metal layer in a local area is obtained in an arbitrary plane passing through the axis of a round hole in a foil mask. Based on the difference in the heights of the surface profile of the thin metal layer in the local area and the surface profile of the flat metal substrate, the geometric thickness of the thin metal layer in the local area is determined without moving the mask. Using an X-ray fluorescence thickness gauge, using standards for the thickness of a solid material of a thin metal layer and a standard for the material of a flat metal substrate, the effective X-ray thickness of a thin metal layer in a local area is determined in the area limited by a round hole in a foil mask, by calculating the ratio of the effective X-ray thickness of a thin metal layer in a local area to the geometric thickness of a thin metal layer in a local area, the ratio of the total volume of open and closed pores in a local area to the geometric volume of a local area is determined, and the integral porosity of the material inside the local area of a thin metal layer is calculated using the formula: P = (1 - h0 / h)⋅100 %, where h0 is the effective X-ray thickness of the thin metal layer in the local region; h is the geometric thickness of the thin metal layer in the local region.EFFECT: increasing the accuracy of non-destructive measurements of the integral porosity of the material of a local region of a thin metal layer of arbitrary shape applied to a flat metal substrate.1 cl, 3 dwg, 1 tbl

Description

[0001] The invention relates to the field of porosimetry and can be used in the electronics industry, mechanical engineering and other fields of technology for non-destructive testing of the distribution of integral (open and closed) porosity in thin metal layers on flat substrates.

[0002] A method for determining the porosity of rocks by liquid saturation is known. The method consists of determining the void volume of a sample by measuring its volume and the difference in mass between the dry and liquid-saturated states. This method is widely used and provides accurate quantitative values ​​of open porosity. (GOST 26450.1-85 Rocks. Method for Determining the Open Porosity Coefficient by Liquid Saturation).

[0003] The disadvantage of this method is that it only determines the average value of open porosity across the entire sample volume. With this method, the porosity measurement results are affected by the choice of saturating liquid, its surface tension, and the wettability of the material surface within the pores. Furthermore, saturating the sample with liquid can affect its properties in subsequent studies.

[0004] Also known is a method for quantitatively determining the porosity of a galvanic coating by anodic polarization and measuring the steady-state current value, characterized in that, in order to ensure the possibility of determining the porosity of a cadmium coating on steel, anodic polarization is carried out in the potential range of 0.10-0.20 V relative to a normal hydrogen electrode in an aqueous solution containing 368-386 g / l of potassium oxalate monohydrate and 18-27 g / l of hydrogen chloride, and the current is measured after a time interval of 2-3 minutes after the start of polarization (SU 1458770, IPC G01N 15 / 08 (2006.01), published 02 / 25 / 1989).

[0005] The disadvantage of this method is that it only determines through porosity and only the cadmium coating on steel.

[0006] A spectroscopic method for determining the porosity of porous materials is known. This method involves preparing a sample of the material being studied, placing it in front of an IR radiation source, and recording its spectrum. A calibration curve of porosity versus absorption coefficient is first constructed using porosity standards made from a monolithic material of the same chemical nature as the sample being studied. A strong absorption band is selected in the recorded spectrum of the sample being studied, and the porosity of the sample being studied is determined using the calibration curve, taking into account its absorption coefficient (RU 2310188, IPC G01N 15 / 08, published 10.11.2007).

[0007] A disadvantage of this method is the inability to determine the porosity of samples deposited on metal substrates. Furthermore, due to the significant absorption of infrared radiation by metals, this method cannot determine the porosity of metal samples.

[0008] The closest to the claimed technical solution in terms of technical essence and the achieved technical result is a method for determining the intergranular effective porosity of rocks in three-dimensional models, including obtaining a three-dimensional tomographic image of the core using the X-ray tomography method, reconstructing a volumetric model of the sample with filtering by averaging voxels, processing the obtained volumetric model of pores by binarization using trash holding, in which the boundary between the rock and the pores is drawn along the histogram of the X-ray density distribution, obtaining a model of the entire volume of the sample and a model of the pore volume. By limiting the obtained model of pores and the model of the entire volume of the sample inside figures of the same dimensions, both limited volumes are measured and the porosity of the sample is calculated (RU 2777714, IPC G01N 23 / 046, G01N 15 / 08, published 08.08.2022).

[0009] A disadvantage of this method is the requirement for samples with a nearly cylindrical shape and transverse dimensions limited by the X-ray absorption of the sample material. Furthermore, implementation of the method involves a labor-intensive and ambiguous mathematical operation called binarization. Consequently, using this method to determine the porosity of a thin metal layer of arbitrary shape deposited on a flat substrate does not provide the required measurement accuracy.

[0010] The technical problem is to determine the integral (open and closed) porosity of the material of a local region of a thin metal layer of arbitrary shape applied to a flat metal substrate, without using porosity standards of the material under study.

[0011] The technical result consists in increasing the accuracy of non-destructive measurements of the integral porosity of the material of a local region of a thin metal layer of arbitrary shape applied to a flat metal substrate, by determining the ratio of the effective X-ray thickness of the thin metal layer, obtained using an X-ray fluorescence thickness gauge, to the geometric thickness of the thin metal layer, obtained using an optical profilograph.

[0012] The essence of the invention is a method for determining the integrated porosity of a local region of a thin metal layer on a flat metal substrate, including determining the ratio of the pore volume in the local region to the geometric volume of the local region of the sample and calculating the porosity of the material within it. The test sample is a thin metal layer of arbitrary shape, with a thickness of 1 to 50 μm, applied to a flat metal substrate.

[0013] To isolate the localized region of interest in a thin metal layer, a foil mask with a circular hole is applied to its surface, confined to the thin metal layer. Using an optical profilograph, a surface profile profile of the flat metal substrate and the surface profile of the thin metal layer in the localized region is obtained in an arbitrary plane passing through the axis of the circular hole in the foil mask. The geometric thickness of the thin metal layer in the localized region is determined from the difference in the heights of the surface profile of the thin metal layer in the localized region and the surface profile of the flat metal substrate.Then, using an X-ray fluorescence thickness gauge and a standard thickness standard for the solid material of the thin metal layer and a standard material of the flat metal substrate, the effective X-ray thickness of the thin metal layer in a local region is determined in the area bounded by the circular opening in the foil mask. By calculating the ratio of the effective X-ray thickness of the thin metal layer in the local region to the geometric thickness of the thin metal layer in the local region, the ratio of the total volume of open and closed pores in the local region to the geometric volume of the local region is determined, and the integral porosity of the material within the local region of the thin metal layer is calculated using the formula:

[0014] P = (1 - h0 / h)⋅100%,

[0015] where h0 is the effective X-ray thickness of a thin metal layer in a local area;

[0016] h- geometric thickness of a thin metal layer in a local area.

[0017] Fig. 1 shows a section of the sample, Fig. 2 shows the surface profile of the sample, Fig. 3 shows the measured profilogram of the surface profile of the sample, the table shows the results of measurements of the geometric and effective X-ray thickness of the thin metal layer in a local area.

[0018] Fig. 1 shows a cross-section of a sample consisting of a flat metal substrate 1 with a thin metal layer 2 applied to its surface. A foil mask 3 with a circular hole 4 in it is located on the surface of the thin metal layer 2. The circular hole 4 with an axis 5 selects a local region 6 in the thin metal layer 2, coaxial with the circular hole 4.

[0019] Fig. 2 shows the surface profile of the sample in a plane passing through the axis 5 of the circular hole 4 in the foil mask 3. The profile contains two sections 7 corresponding to the surface of the flat metal substrate 1, two sections 8 corresponding to the surface of the thin metal layer 2, two sections 9 corresponding to the surface of the foil mask 3, and a section 10 corresponding to the surface of a local region 6 of the thin metal layer 2 inside the circular hole 4 in the foil mask 3.

[0020] In the proposed method, a thin metal layer 2 (Fig. 1) of arbitrary shape with a thickness of 1 to 50 μm, applied onto a flat metal substrate 1, is used as the test sample. The lower limit of the thickness of the thin metal layer 2 is determined by the capabilities of the optical profilometry method, the roughness and flatness of the flat metal substrate 1 and the roughness of the thin metal layer 2 being tested. The upper limit of the thickness of the thin metal layer 2 used is determined by the thickness measurement range of the X-ray fluorescence thickness measurement method.

[0021] In order to reduce the influence of the deflection of the flat metal substrate 1, with the thin metal layer 2 being investigated applied to it, on the results of determining the geometric thickness of the thin metal layer 2 in the local region 6 by the optical profilometry method, the thickness of the flat metal substrate 1 should significantly exceed the thickness of the thin metal layer 2 applied to it and be more than 1 mm.

[0022] To isolate the local area 6 to be examined in the thin metal layer 2, a foil mask 3 with a round hole 4 with a diameter of at least 1 mm is applied to its surface. The foil mask 3 should not extend beyond the thin metal layer 2.

[0023] The thickness of the foil from which the mask is made is determined by the ease of attaching foil mask 3 to the surface of thin metal layer 2 during the measurements provided by the proposed method, and the range of surface profile heights recorded by the optical profilograph. The minimum size of the circular aperture 4 in foil mask 3 must exceed the size of the collimated X-ray beam of the X-ray fluorescence thickness gauge used. The maximum size of the circular aperture 4 in foil mask 3 is determined by the dimensions of the applied thin metal layer 2.

[0024] Using an optical profilograph, a profilogram (Fig. 2) is obtained in an arbitrary plane passing through the axis 5 of the circular opening 4 in the foil mask 3. The profilogram consists of two sections 7 of the surface profile of the flat metal substrate 1, two sections 8 of the surface profile of the thin metal layer 2 under study, two sections 9 of the surface profile of the foil mask 3, and a section 10 of the surface profile of the thin metal layer 2 under study in a local area 6. The slope of the profilogram is aligned using the two sections 7 of the surface profile of the flat metal substrate 1, located at the edges of the profilogram. The geometric thickness h of the thin metal layer 2 in a local area 6 is determined using the difference in the heights of section 10 of the surface profile of the thin metal layer 2 in a local area 6 and section 7 of the surface profile of the flat metal substrate 1.

[0025] To align the slope of the profilogram, the surface of the flat metal substrate 1 in the area corresponding to sections 7 of the profilogram should not be covered with a thin metal layer 2 and should have dimensions of at least 3 mm.

[0026] To increase the representativeness of the results of determination in the local region 6 of the geometric thicknessh of the thin metal layer 2 being investigated, the profilogram measurement is performed several times, rotating the sample being investigated around the axis 5 of the round hole 4 in the foil mask 3 at a random angle, and the average value of the geometric thicknessh of the thin metal layer 2 being investigated is calculated.

[0027] To determine the porosity of the thin metal layer 2 under study, in addition to the geometric thickness h of the thin metal layer 2, its effective X-ray thickness h0 is determined. The effective X-ray thickness is the equivalent thickness of a solid material that has the same X-ray absorption as the porous material.

[0028] Using an X-ray fluorescence thickness gauge, using the thickness standards of the solid material of the thin metal layer 2 and the material standard of the flat metal substrate 1, the effective X-ray thickness h0 of the thin metal layer 2 in the selected local area 6 is determined in the area limited by the round hole 4 in the mask made of foil 3.

[0029] To increase the representativeness of the results of determining the effective X-ray thickness h0 of the thin metal layer 2 being investigated in the local region 6, measurements are performed several times by randomly moving the collimated X-ray beam of the thickness gauge within the circular opening 4 in the foil mask 3, and the average value of the effective X-ray thickness h0 of the thin metal layer 2 being investigated is calculated.

[0030] The integral porosity of the material inside a local area of ​​a thin metal layer is calculated using the formula:

[0031] P = Vp / V⋅100%= (1 ​​- Vm / V)⋅100% =(1 - h0 / h)⋅100%,

[0032] where Vp is the total volume of open and closed pores inside a local area of ​​a thin metal layer;

[0033] V- geometric volume of the local region of the thin metal layer;

[0034] Vm- volume of material in the local area of ​​a thin metal layer;

[0035] h0-effective X-ray thickness of thin metal layer in local area;

[0036] h is the geometric thickness of the thin metal layer in the local area.

[0037] Example. The test sample consists of a thin silver layer 13 mm in diameter, obtained by low-temperature sintering of silver-containing paste ASP-043 (Heraues), located on the surface of a flat molybdenum substrate 24 mm in diameter and 1.4 mm thick.

[0038] A stainless steel foil mask with a diameter of 10 mm, a thickness of 0.18 mm, and a round hole with a diameter of 4 mm in the center of the foil mask is placed on the surface of the thin silver layer, without extending beyond its limits.

[0039] Using the Cyberscan Vantage 2 optical profiler, a profilogram of the surface profile of a flat molybdenum substrate, a thin layer of silver, a foil mask, and a thin layer of silver inside the round hole in the foil mask is obtained in an arbitrary plane passing through the axis of the round hole in the foil mask (Fig. 3).

[0040] Using the profilograph software, the slope of the flat molybdenum substrate's surface profile is aligned using two sections located at the edges of the profilogram. The geometric thickness h of the thin silver layer in the localized area within the circular aperture in the foil mask is determined from the difference in height between the surface profile of the thin silver layer in the localized area and the surface profile of the flat molybdenum substrate. Without moving the foil mask relative to the surface of the thin silver layer, the test sample is rotated at a random angle around the axis of the circular aperture in the foil mask, and the measurements are repeated.

[0041] A MAXXI 6 X-ray fluorescence thickness gauge is used to determine the effective X-ray thickness h0 of a thin silver layer in a localized area. Measurements are performed at a voltage of 40 kV on the X-ray tube with an X-ray beam aperture diameter of 0.5 mm. Oxford Instruments' thickness gauge standards for a solid silver layer and a thick molybdenum layer standard are used for calibration. Without moving the foil mask relative to the surface of the thin silver layer, the effective X-ray thickness h0 of the thin silver layer under study is determined in a localized area bounded by a circular opening in the foil mask. The measurements are repeated for other random positions of the X-ray beam within the localized area under study.

[0042] The measurement results are presented in the table. The average geometric thickness h of the thin silver layer in the localized area inside the circular hole in the foil mask was 27.7 μm. The average effective X-ray thickness h of the thin silver layer in the localized area inside the circular hole in the foil mask was 21.1 μm. The integral porosity of the material within the localized area of ​​the thin metallic silver layer is calculated using the formula:

[0043] P = (1 - h0 / h)⋅100%,

[0044] where h0 is the effective X-ray thickness of a thin layer of silver in a local area;

[0045] h- geometric thickness of a thin layer of silver in a local area.

[0046] The measured value of the integral porosity of the silver layer in the local area was 24%.

[0047] The invention makes it possible to determine, in a non-destructive manner, the integral porosity of the material of a local region of a thin metal layer of arbitrary shape applied to a flat metal substrate, by determining the ratio of the effective X-ray thickness of the thin metal layer, obtained using an X-ray fluorescence thickness gauge, to the geometric thickness of the thin metal layer, obtained using an optical profilograph.

[0048] Table

[0049] h, μm 27,9 27,8 27,5 27,5 27,4 27,6 27,7 27,8 27,9 27,5 h 0 , μm 20,4 22,1 21,1 20,9 20,2 22,0 22,3 22,1 20,3 20,0

Claims

A method for determining the integral porosity of a local region of a thin metal layer on a flat substrate, including determining the ratio of the pore volume to the geometric volume of the selected region and calculating the porosity of the material in it, characterized in that a thin metal layer of arbitrary shape with a thickness of 1 to 50 μm applied to a flat metal substrate is used as the test sample; in order to isolate the local region under study in the thin metal layer, a foil mask with a round hole is applied to its surface; using an optical profilograph in an arbitrary plane passing through the axis of the round hole in the foil mask, a profilogram of the surface profile of the flat metal substrate and the surface profile of the thin metal layer in the local region is obtained,based on the difference in the heights of the surface profile of the thin metal layer in the local area and the surface profile of the flat metal substrate, the geometric thickness of the thin metal layer in the local area is determined without moving the mask, using an X-ray fluorescence thickness gauge, using standards for the thickness of the solid material of the thin metal layer and a standard for the material of the flat metal substrate, the effective X-ray thickness of the thin metal layer in the local area is determined in the area limited by the round hole in the foil mask, calculating the ratio of the effective X-ray thickness of the thin metal layer in the local area to the geometric thickness of the thin metal layer in the local area, the ratio of the total volume of open and closed pores in the local area to the geometric volume of the local area is determined, and the integral porosity of the material inside the local area of ​​the thin metal layer is calculated using the formula:, P = (1 - h0 / h)⋅100%, where h0 is the effective X-ray thickness of a thin metal layer in a local area; h is the geometric thickness of a thin metal layer in a local region.

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