This standard adopts ISO 9220-1988(E) by reference. This standard specifies the technical requirements for the scanning electron microscope measurement method for the cross-sectional thickness of metal coatings. This standard is applicable to the measurement of the thickness of metal coatings in the cross section from micrometers to millimeters. JB/T 7503-1994 Scanning electron microscope measurement method for the cross-sectional thickness of metal coatings JB/T7503-1994 Standard download decompression password: www.bzxz.net
This standard adopts ISO 9220-1988(E) by reference. This standard specifies the technical requirements for the scanning electron microscope measurement method for the cross-sectional thickness of metal coatings. This standard is applicable to the measurement of the thickness of metal coatings in the cross section from micrometers to millimeters.

Mechanical Industry Standard of the People's Republic of China
JB/T 7503-94
Metallic Covering Cross-Section Thickness
Scanning Electron Microscope Measurement Method
Published on October 25, 1994
Ministry of Machinery Industry of the People's Republic of China
Implementation on October 1, 1995
Mechanical Industry Standard of the People's Republic of China
Metallic Covering Cross-Section Thickness
Scanning Electron Microscope Measurement Method
JB/T7503-94
This standard adopts ISO9220-1988 (E) "Metallic Covering-Determination of Covering Thickness-Scanning Electron Microscope Method". Subject Content and Scope of Application
This standard specifies the technical requirements for the scanning electron microscope measurement method for the cross-section thickness of metallic coverings. This standard is applicable to the measurement of the thickness of metallic coverings in the micrometer to millimeter range in the cross section. 2 Reference standards
GB6462
GB12334
3 Terms
Local thickness
Method for measuring the cross-sectional thickness of metal and oxide coatings with microscope For the definition and general rules of thickness measurement of metal and other inorganic coatings, see GB12334.
Measurement principle
Cut a block sample perpendicular to the coating from the specified position of the test piece, and make a cross-sectional metallographic sample through inlaying, grinding, polishing and etching, and measure it with a scanning electron microscope.
Measure the traditional microscopic image on the observation screen with a microscopic image micro-ruler, or measure the film (negative) with a photo enlarger or directly measure the enlarged photo (positive).
5 Instruments
5.1 Scanning electron microscope (SEM)
The resolution is equal to or better than 10nm.
5.2 Metal standard microscale
Use metal standard microscale to calibrate the magnification of SEM, or calibrate the microscale of microscopic image. The magnification error of metal standard microscale is less than 3%.
Factors affecting the accuracy of thickness measurement
6.1 Surface roughness: see 2.1 of GB6462. 6.2, Slope of sample cross section; see 2.2 of GB6462. 6.3
Slope of sample placement: Any slope relative to the electron beam caused by incorrect placement of the sample cross section may cause incorrect measurement results.
Deformation of covering layer: see 2.3 of GB6462. 6.5 Chamfer of covering layer edge: see 2.4 of GB6462. Approved by the Ministry of Machinery Industry on October 25, 1994
Implemented on October 1, 1995
Additional coating: See 2.5 of GB6462.
Etching: See 2.6 of GB6462.
Masking: See 2.7 of GB6462.
Poor contrast
JB/T 750394
When the atomic numbers of metals are close, the boundaries between several covering layers and between the covering layer and the substrate have poor visual contrast in the observation screen and appear unclear. For example, the boundary between bright and semi-bright nickel layers should be clearly identified by appropriate etching and SFM techniques. For some metal combinations, energy dispersive X-ray technology (see A2.3) or backscattered electron imaging technology (see A2.4) is used.
6.10 Magnification
For a given coating thickness, the measurement error tends to increase as the magnification decreases. The magnification should be selected according to practical conditions so that the field of view is 1.5 to 3 times the coating thickness. The magnification error index of a general commercial scanning electron microscope is ±10%. A metal standard microscale ruler can be used to correct the magnification to reduce the error of the magnification. Uniformity of magnification
Since the magnification of the entire field of view may be uneven, the magnification error index of a general commercial scanning electron microscope between the center and corners of the display screen is less than 25%. Therefore, correction and measurement must be performed at the same part of the field of view to avoid errors caused by uneven magnification. 6.12 Stability of magnification
6.12.1 The metal standard microscale ruler and the sample to be tested can be installed on the same sample holder or separately. Use the sample column height adjuster to ensure that the cross-section of the sample is at the same level as the plane of the standard microscale, so that the sample thickness and standard scale can be determined in a shorter time and the influence of magnification stability can be reduced. 6.12.2 After the scale of the standard microscale is photographed, without using the focus control and other electronic controls, adjust the X, Y and Z torsion arms of the sample stage to keep the test sample at the focus of the electron beam of the SEM to prevent the magnification from changing when adjusting the focus or other electronic controls (e.g., grating rotation, acceleration voltage, contrast). 6.13 Stability of Microscopic Images
The size of the microscopic image may change with time, temperature and humidity. If the scale image of the standard microscale and the sample thickness microscopic image are taken with the same film and printed on the same photographic paper and placed together, the errors caused by the change of the microscopic image and size can be reduced. Resin-coated photographic paper is recommended.
Preparation of Cross-Section
The measurement sample is prepared as follows: Cut the sample into a cross section perpendicular to the surface of the cover layer. b.
The surface of the coating in the cross-sectional specimen shall be flat and the entire width of the image shall be in focus at the same time when measured at the magnification used. All deformed material produced during cutting and preparation of the cross section shall be removed. The interface on the cross section of the coating shall be clearly defined by the contrast of the appearance alone or by a thin line that is easily distinguishable. Note: See Chapter A1 in Appendix A (reference) for details. Instrument calibration
8.1 Overview
Before using the instrument, calibrate the instrument magnification by taking a scale image using a metal standard microscale under the same conditions as the test specimen.
Pay attention to the factors affecting the results listed in Chapter 6, the measurement methods specified in Chapter 9, and the error limits specified in Chapter 10. The stability of the calibration should be checked frequently.
8.2 Video
Use the brightness and contrast automatic control switch to capture the scale image of the standard micro-scale and the cross-sectional thickness of the coating layer to be measured later 2
JB/T 750394
microscopic image. Or when the brightness and contrast are adjusted manually, the conditions for capturing the scale image and the thickness image must be the same, and there must be sufficient image contrast.
Use the differential image emphasis wheel to make the boundary clear, so as to facilitate the thickness measurement. 8.3 Measurement
8.3.1 Use a micrometer to measure the image film (negative film) captured by the photo enlarger or directly measure the enlarged image photo (positive film). Measure the vertical distance between the centers of the two lines in the captured image, with a visual accuracy of 0.1mm. 8.3.2 Repeat the measurement at least 3mm apart and at more than 3 different locations on the sample to determine the average distance. 8.4 Calculation of magnification
On the scale image, divide the average distance between the scale lines of the metal standard microscale by the scale line calibration distance to calculate the magnification of the image.
× 1000
Where: F--magnification;
L.--average distance between the scale lines of the image, mm; L--scale line calibration distance, um.
9 Measurement method
9.1 The scanning electron microscope shall be operated and used in accordance with the manufacturer's instructions, and attention shall be paid to the factors listed in Chapter 6 and the error requirements in Chapter 10. (1)
9.2 Take a cross-sectional thickness microscopic image under the same conditions as for calibration, and measure the microscopic image. The operation shall be carried out in accordance with 9.2.1 and 9.2.2.
9.2.1 Take a clear scale image of the metal standard microscale and a conventional microscopic image of a cross-sectional specimen with a clear cover layer and a defined boundary. For covering layer samples without obvious boundaries, the composition of the samples can be determined using X-ray images and backscattered electron images. 9.2.2 Use a vernier caliper or a high-precision ruler to measure the microscopic image of the film (negative film) magnified several times by the photo enlarger, or directly measure the photo (positive film) magnified several times.
9.3 Thickness calculation formula
Where: d--covering layer thickness, μm; www.bzxz.net
×1000
L. Straight-line distance between the boundaries of the covering layer in the microscopic image, mm; r——magnification (see 8.4);
18----120 The length of the microscale in the film microscopic image, mm (for SEM manufactured by Hitachi); L,—the calibrated length of the above microscale, um. 10 Measurement error
The calibration and operation of the instrument should ensure that the error of the measurement of the covering layer thickness is less than 10% or 0.1um (whichever is larger, see A2.5).
Result expression
The result is expressed in micrometers (um), with an accuracy of 0.01um, however, if the result is greater than 1μm, use three digits. Note: This requirement is used to reduce the measurement error caused by the processing of calculated values. 12 Test report
The test report shall contain at least the following contents:
The marking of the sample and the measurement location on the sample; the thickness measurement value;
The correction value of the magnification of the sample before and after measurement: the main factors that may affect the measurement results;
JB/T7503-94
The measurement image category: the secondary electron image, scattered electron image, absorbed electron image, transmitted electron image or the image composed of X-ray image and backscattered electron image in the traditional microscopic image method. f.
The measurement date and the name of the measurer.
JB/T750394
Appendix A
Guide to the preparation and determination of cross sections
(reference)
The preparation of cross sections of metal coatings depends mainly on the individual processes and their specific technologies. There are many applicable technologies. It is inappropriate to stipulate only one set of technologies, but it is impractical to include all appropriate technologies. The contents described in this appendix are for reference only. A1 Preparation of cross sections
A1.1 Inlay
In order to prevent the edge of the cross section of the metal coating from being chamfered, the specimen is often overlapped with a metal with a hardness close to that of the coating to support the outer surface of the coating. The thickness of the overlapped layer is at least 10um, and the electrical signal of the overlapped layer should be different from that of the coating. The test specimen can be clamped with a fixture or inlaid with bakelite powder, epoxy resin, low-melting alloy, etc. There should be no gap between the inlay material and the coating layer, and between the overlapped layer and the coating layer, and the inlay material and surface must be conductive to prevent charge accumulation. A1.2 Grinding and polishing: see Chapter A2 of GB6462. A1.3 Etching: see Chapter A3 of GB64G2. A2 Use of scanning electron microscope
A2.1 When measuring thickness according to the cross-sectional morphology revealed by the traditional microscopic image, if the boundary where the coating and the substrate intersect is not clear and is revealed only by contrast, the apparent width of the cross-sectional area of ​​the coating will change with the adjustment of contrast and brightness, and this change can be as high as 10%. In order to reduce the error generated, the contrast and brightness should be adjusted so that the morphological images of the coating and substrate structures are displayed. A2.2 Since the magnification of the scanning electron microscope will change with time and changes in instrument adjustment, the sample should be measured immediately after the instrument is calibrated. After the test measurement, the instrument should be calibrated immediately. For strict measurement, the average value of the calibrated measurement values ​​before and after the sample measurement should be used. A2.3 Many SEMs are equipped with energy dispersive X-ray spectrometers (EDS). For the case where the boundary contrast between the coating and the substrate is poor, it is useful to use X-ray images for thickness measurement. The best resolution of EDS is about 1μm. A2.4 The composition image of the backscattered electron image is helpful to identify metal layers with an atomic number difference of 1. This can only be achieved when the SEM is equipped with two detector devices arranged symmetrically relative to the electron beam axis. Its resolution is 0.1um. A2.5 There are no reports on extensive research on measurement errors. The measurement error of the microscale in the microscopic image photo corrected with a metal standard microscale is less than 1% (at a magnification of 1000), which does not include the inherent error of the standard microscale and other factors. The error in measuring thickness using the microscale in the microscopic image is less than 0.01μm. Additional notes:
This standard was proposed and coordinated by the Wuhan Materials Protection Research Institute of the Ministry of Machinery Industry. This standard was drafted by the Wuhan Materials Protection Research Institute. The main drafters of this standard are Liu Fuxing and Xia Zhengcai. 5
People's Republic of China
Mechanical Industry Standard
Metallic Covering Layer Transverse Surface Thickness
Scanning Electron Microscope Measurement Method
JB/T7503-94
Published by the Machinery Standardization Research Institute of the Ministry of Machinery Industry Printed by the Machinery Standardization Research Institute of the Ministry of Machinery Industry (P.O. Box 8144, Beijing
Zip Code 100081)
Copyright reserved
Reproduction is prohibited
Sheet 1/2
Format 880×12301/16
First edition in October 1995
Word count 10,000
First printing in October 1995
Number 00,001~500
Price 3.00 Yuan
No. 94-281
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