This standard specifies the method for measuring the thickness of metal coatings. This standard is applicable to the measurement of the thickness of metal coatings with a thickness of 0.01~1000μm, especially for measuring the thickness of thin coatings; when the thickness is less than 0.01μm, the straightness and smoothness of the workpiece surface are very high, and the thickness measurement is difficult. This method is applicable to the thickness measurement of the standard block for the thickness of the coating. GB/T 11378-1989 Method for measuring the
thickness of metal coatings with a thickness of 0.01~1000μm, especially for measuring the thickness of thin coatings; when the thickness is less than 0.01μm, the straightness and smoothness of the workpiece surface are very high, and the thickness measurement is difficult. This method is applicable to the thickness measurement of the standard block for the thickness of the coating.

National Standard of the People's Republic of China
Metallic coatings. Measurement of coating thickness-Profilometric method
Metallic coatings. Measurement of coating thickness-Profilometric methodGB 118T 889
This standard is equivalent to the international standard 1S01518--1980 "Metallic coating thickness-Profilometric method". Subject content and scope of application
This standard specifies the profilometric method for measuring the thickness of metallic coatings. This standard is suitable for measuring the thickness of metallic coatings with a thickness of 1.01 to 1000μm, especially for measuring the thickness of thin coatings. When the thickness is less than 0.01m, the requirements for the flatness and smoothness of the surface of the part are very low, and it is difficult to measure the original quality. This method is applicable to the thickness measurement of the standard for the preparation of coating thickness. 2 Reference standards
GB 61 Instrument terminology for measuring surface roughness by profilometry GB62 Profilometry stylus surface roughness measuring instrument Profilometry recorder and center line profilometry GB4953 Anodic dissolution coulometric method for measuring the thickness of metal coatings 3 Principle
By dissolving part of the coating or shielding part of the substrate before plating, a step is formed between the substrate and the coating, and then the height of the step is measured by a profilometry recorder. This height is the thickness of the coating. 4 Test instruments
Both types of profilometry recorders can be used 4.1 Electronic stylus instruments, namely surface analyzers and surface profilometry, are usually used to measure surface roughness, but this standard uses them to record the step. Their measuring characteristics are as follows: Measuring length
Measuring thickness range
Resolution (determined by measuring range)
4.2 Inductance comparator
Its measuring characteristics are as follows:
Measuring length
Measuring thickness range
Resolution (determined by measuring range)
Used:
1 150 45184: 30. 01115 ~ 1 μm. Approved by the State Administration of Technical Supervision on June 29, 1989 1 -100mm
0.15～250μm
0. 005 ~1μmll
1 ~100μm
4, 02 ~ 20μm
Implemented on January 1, 1990
5 Measurement method
5.1 Preparation of steps
GB 1137889
The steps are prepared by removing a part of the covering layer. The preparation of steps requires that the substrate and the top of the step are not damaged and corroded, and there should be no trace of the covering layer at the bottom of the step. The method for preparing steps is as follows. 5.1.1 Use appropriate materials to cover the entire area except the dissolution area. Then dissolve the unshielded covering layer with an appropriate reagent that does not corrode the substrate, and finally remove all the shielding materials.
5.1.2 Remove a small area of ​​coating using the electrolytic cell used in GB1955. If the stylus crosses the diameter of the circular pit formed by the small electrolytic cell in one direction, the outline of two steps can be felt. Remove the coating of four small circular areas in a 1 cm square. Then measure the height of the step by measuring the square from the step near each corner (see Figure 1).
5.1.3 Sometimes, the step is made by masking a part of the body before covering. The diameter of the masked surface is about 1 to 2 mm so that the boundary formed will not interfere with the measurement.
5.2 Rolling requirements
Determine the operating parameters according to the instrument and workpiece conditions, paying special attention to the factors affecting the measurement accuracy described in Section 6, and record the outline according to the instrument's operating instructions.
5.3 Thickness measurement
According to the two contour recording lines at the top and bottom of the step, draw the center line of each, and extend them so that the center line is directly above the other center line. The distance between the two center lines at the step point is measured as the step height, that is, the thickness of the cover layer. When making such measurements, the boundary effect should be avoided, and the variation of the cover layer thickness along the contour of the step should also be considered. 5.4 Measurement accuracy
The calibration and operation of the instrument should ensure that the measurement accuracy of the cover layer thickness is within the range of 10 μm (the larger error is taken). 6 Factors affecting accuracy
6.1 Contour recording
Because the thickness measurement is carried out on the contour to be recorded, if the step cannot be correctly drawn under a suitable magnification, the measurement error will increase. Inaccurate records may be caused by the poor quality of the recorder or improper adjustment. 6.2 Vertical magnification
If the vertical magnification is too low, the measurement accuracy will be poor. In this case, the magnification should be adjusted to the best width of the step profile recorded on the reference paper.
6.$ Graphic measurement
If the test plane is not parallel to the instrument reference surface, the horizontal record is inclined to the record paper grid and the vertical part of the step is also redundant. Of course, for certain selected combinations of vertical and horizontal magnification, stylus radius and step height (i.e. thickness), it can also be perpendicular to the record paper grid. When the profile is inclined, if the horizontal magnification and vertical magnification are not properly adjusted, errors will often occur when measuring the vertical distance between the center lines of the profile. GB 11378—89
In order to avoid these errors or additional mathematical operations, the instrument reference surface and the test surface should be aligned. This can be achieved by suitable fixtures and assemblies.
6.4 Magnitude of measuring force
If the measuring force on the stylus is too great, the stylus may be scratched or deformed, which may introduce measurement errors. Therefore, the measuring force should be kept to a minimum and should not exceed the reasonable values ​​given in Table A1 in Appendix A. 6.5 Stylus diameter and surface roughness
For rough surfaces, it is more appropriate to use a large-diameter stylus. If a small-diameter stylus is used at this time, the height of the step is difficult to measure accurately because the top and bottom contours of the step to be measured are difficult to determine. For surfaces with different roughness, the error is smaller when a small-diameter stylus is used. If a large-diameter stylus is used at this time, the contour of the step to be measured is distorted because the distance between the friction peaks on the two surfaces is different, and the stylus is more likely to be at a higher point on one surface than on the other.
A small-diameter stylus equipped with an electronic filter can produce a semi-smooth contour, but the corners of the step contour may become rounded. In principle, the recorded substrate roughness (the height from the peak to the bottom of the surface profile) should not exceed 10% of the step height. 6.6 Moving vibrations can cause irregularities or disturbances in the recorded profile, making it difficult to make precise measurements. The instrument should be isolated from the vibration source to minimize its influence. In principle, the peak to valley height should not exceed 10% of the step height. 6.7 Surface curvature Surface curvature will hinder the accurate measurement of step profiles, so it is best to measure on a flat surface as much as possible. If the measurement is made on a curved surface, the movement of the recording needle should be in the direction of the smallest curvature. For example, when measuring on a round surface, the recording needle should move in the direction of the axis.
6. Cleanliness
Any attachments, such as dust, grease and corrosion, will cause inaccurate measurements. Therefore, the surface to be measured should be cleaned and the air in the laboratory should be basically clean and dust-free. 6.9 Temperature
Temperature changes can affect the measurement. Therefore, the temperature should be kept uniform and stable. 6.10 Step shape
If the step is not well made (e.g. the corners are too round), it is difficult to determine the plane height between the top and the bottom of the step, which will cause difficulties in precise measurement. Therefore, the step should be made carefully.
6.11 Reference surface
Two reference surfaces are used: one is a circular guide that straddles the surface of the sample and slides on the sample to form a reference surface, and the other is a reference surface provided by the instrument reference accessory. It does not depend on the sample and is an auxiliary guide surface with a nominal shape similar to the contour of the sample. When the stylus slides along the reference surface with its bracket, the point motion of the stylus relative to the landing surface is recorded by the instrument. The reliability of the wheel record determines the mass ball (slippage and straightness) before the reference. . 6.12 Calibration
The thickness measurement error will not be less than the calibration error of the instrument and the error of the standard step height used to calibrate the instrument. Because the instrument may change after calibration, it needs to be calibrated again. The number of calibrations is determined based on experience. Even if the instrument is calibrated carefully, there may still be a 2% error due to the nonlinear characteristics of the instrument. To minimize this error, the instrument can be calibrated at two points close to the sides of the step to be measured. 7 Calibration bzxZ.net
7.1 The instrument should be calibrated according to the instrument manual and the influencing factors listed in Section 6 should be appropriately considered. 1.2 The standard block required for the calibration instrument should have a known step height error and be less than 10.5. However, if the combined step height is less than 10.1μm, the error may be much greater than 5%.
1.8 Repeat the calibration every certain period of time and whenever there is a suspicion of a change in the calibration (see 6.12). A1 Electronic stylus instrument
Its content is as follows:
GB 1137889
Appendix A
Two types of profile recorders
(Supplement)
A1.1 A conical or pyramidal stylus sensor with an included angle of 1.57 radians (90°) or 1.05 radians (60°), the nominal radius of the stylus tip being 2, 5, 10 or 50 μm, and the maximum static measuring force of its contact with the sample surface being as shown in A1. Table Al Jiang static measurement force on the stylus
Stylus tip half nominal, um
Melt needle static measurement force on the stylus average height
The most human, ()
1.0007 (0.07)
Company: 1) Suitable for low hardness metals such as radiation and. 5
0.004 (0.4)
0.016 (1.6)
0.01 (1.0)
A1.2 "A moving unit that slides the sensor along the reference track of the guide head. If the guide head may cause damage to the measured surface or deform the measured step, the sensor should slide along: a reference with a nominal shape of the wheel. A1.3 An amplification unit that amplifies the weight of the wheel can be selected from a nominal value of 1 to 10\ (V). A1.4 A recorder that depicts and amplifies the changes in the wheel. When used in conjunction with the moving unit, it can magnify the water half of the wheel to a nominal value of 1h~×10\ (V) A2 Inductance comparator|| tt||A2.1 The design of the inductance comparator is very similar to that of an electronic stylus instrument, the main difference being that the stylus has a large radius and cannot depict the fine contours of the surface.
A2.2 Operating parameters of an inductance comparator 1 A typical example is as follows: An inductance comparator with a table that enables the scanned surface to move in a straight line, a matching amplifier, and a load tolerance of not less than 0.5% uses the following operating parameters:
Stylus radius
Maximum magnification
Stylus static measurement maximum
Additional remarks:
250μr
50 000X
This standard was proposed by the Ministry of Machinery and Electronics Industry of the People's Republic of China. This standard was issued by the Technical Committee for Standardization of Metallic and Non-metallic Coatings 11. This standard was drafted by the Wuhan Institute of Materials Protection. The main drafter of this standard was Zhu Zhengniu.
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