Measurement of metallic coating thickness X-ray spectrometric methods
Some standard content:
GB/T 169211997
This standard is formulated based on ISO8497.1990 "Metallic Cover Thickness Measurement by X-ray Spectrometry". It is equivalent to the international standard in terms of technical content and is basically the same as the international standard in terms of writing rules.
Compared with ISO3497, 1990, this standard is different in the numbering and arrangement of chapters 6 and 7, but the content and sequence are different. Appendix A of this standard is the appendix of the standard.
This standard replaces JB/T5068--91 "Metallic Cover Thickness Measurement by X-ray Spectrometry" from the date of its release and implementation.
This standard is proposed by the Ministry of Machinery Industry of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Standardization of Metallic and Non-metallic Coverings. The drafting unit of this standard: Wuhan Institute of Materials Protection, Ministry of Machinery Industry. The main drafter of this standard is Zhu Zhengsheng.
GB/T16921—1997
ISO Foreword
ISO (International Organization for Standardization) is a worldwide association of national standards bodies (ISO member bodies). The work of formulating international standards is generally carried out through IS technical committees. If each member body is interested in a subject determined by a technical committee, it has the right to make a statement to the committee. International organizations, both governmental and non-governmental, that have relations with ISO may also participate in the work. In all aspects of electrotechnical standardization, ISO works closely with the International Electrotechnical Commission (IEC).
The draft international standard adopted by the technical committee is sent to the member bodies for approval before it is adopted as an international standard by the ISO Council. According to ISO procedures, the member bodies that participate in the voting must have a minimum approval rate of 75% before it can be published as an international standard. International Standard ISO3497 was prepared by ISO/TC107 Technical Committee on Metallic and Other Inorganic Coatings. This second edition replaces and cancels the first edition (ISO3497, 1976) and is its technical revision. Appendix A is an integral part of this international standard. 1 Scope
National Standard of the People's Republic of China
Metallic Coating Thickness Measurement
X-ray Spectrometry Method
Measurement of Metallic Coating ThicknessX-ray Spectrometry Methods
This standard specifies the X-ray spectroscopy method for measuring the thickness of metallic coatings, GB/T 16921--1997
eqv ISO 3497:1990
The method specified in this standard is a non-contact non-destructive thickness measurement method that can simultaneously measure a number of three-layer systems. The measurement method used in this standard is basically a method for determining the mass per unit area. If the density of the coating material is known, the measurement result can also be expressed in terms of the linear density of the coating. The actual thickness measurement range of the coating material depends on the allowable measurement uncertainty. It also varies with the instruments and operating conditions used. The typical measurement ranges of commonly used metallic coating materials are shown in Appendix A (Standard Appendix). 2 Definitions
This standard adopts the following definitions.
2.1X-ray fluorescence (XRF)
Secondary radiation generated by high-energy incident X-rays irradiating a material. This secondary radiation has the wavelength and energy characteristics of the material. 2.2Fluorescence radiation intensity
Radiation intensity expressed in counts per second (radiation pulses) measured by the instrument. 2.3Normalized intensity (I)
Normalized fluorescence radiation intensity. The normalized intensity is independent of the measuring instrument, measuring time, and excitation radiation intensity. However, the geometric structure of the measuring system and the excitation radiation energy affect the normalized count rate.
Normalized intensity I. Given by formula (1):
Where, 7. Fluorescence radiation intensity measured on the coating sample; I. Fluorescence radiation intensity measured on the uncoated substrate material; I. Fluorescence radiation intensity measured on the coating material with a thickness greater than or equal to the saturation thickness; I, are measured under what conditions.
2.4 Shot and thickness
The minimum thickness at which the fluorescence radiation intensity of the material no longer changes detectably with the increase of the thickness of the material under certain conditions. Note 1: The saturation thickness is taken as the relationship between the energy or wavelength of the fluorescence radiation, the density and atomic number of the material, and the incident angle, the light radiation and the surface of the material. 2.5 Intermediate cover
Located between the surface cover and the base material, the thickness should be less than the saturation thickness of each layer. Note 2: In the measurement, the intermediate cover with a thickness exceeding the saturation thickness can be regarded as the real base. Approved by the State Administration of Technical Supervision on July 25, 1997 and implemented on February 1, 1998
2.6 Count rate
GB/T16921—1997
The number of fluorescence radiation pulses recorded by the instrument per unit time. 3 Principles
3.1 Basic Principles
The mass per unit area of the covering layer (or the linear thickness of the covering layer if the density is known) and the intensity of the generated fluorescence radiation have a certain relationship. Through any practical detection instrument, the relationship curve is first drawn using a standard combination of known unit mass (or thickness), and then the radiation intensity of the sample to be tested is measured under the same conditions. The mass per unit area (or thickness) of the covering layer is obtained through the relationship curve. The density of the covering layer material is the density of the covering state, not the theoretical density of the covering material during measurement. The fluorescence intensity is a function of the atomic number of the element. The covering layer (including the intermediate covering layer) and the substrate with different atomic numbers will produce their own characteristic radiation. By selecting one or more energy bands and adjusting the appropriate detection system, the surface covering layer and the intermediate covering layer can be measured simultaneously. 3.2 Excitation
3.2.1 Overview
The determination of metal coating thickness by X-ray spectroscopy is based on the fact that a strong and narrow beam of polychromatic or monochromatic X-rays is irradiated on the substrate and coating to produce secondary radiation of different wavelengths or energies. These secondary radiations have the characteristics of the elements constituting the coating and substrate. Usually, a high-voltage X-ray generator or appropriate radioactive isotopes are used to excite the secondary radiation. 3.2.2 Excitation by high-voltage X-ray tube
The X-rays generated by an X-ray tube with an external high voltage under stable conditions are irradiated on the sample to be tested through a collimator to produce excitation. It can provide higher radiation intensity. It can measure very small areas, and control and safety protection are also relatively easy. 3.2.3 Excitation by radioactive isotopes
The radiation is produced by selecting a suitable radioactive isotope source and irradiating it on the sample to be tested through a collimator. The energy of the ideal excitation ray should be slightly higher than the required characteristic X-ray energy. Only a few radioactive isotopes emit gamma rays that are included in the energy band suitable for coating thickness measurement. The structure of the radioisotope excited instrument is compact, no cooling device is required, and the radiation provided is basically monochromatic with low background intensity. However, its radiation intensity is low, so it cannot measure small areas, and its life span is short. Pay attention to personal protection when using high-intensity isotope sources. 3.3 Dispersion
3.3.1 Overview
The binary radiation generated by X-ray irradiation on the surface of the coating usually contains multiple wavelengths or energies. Wavelength dispersion and energy dispersion can be used to separate the components required for coating thickness measurement. 3.3.2 Wavelength dispersion
Use a crystal spectrometer to separate the characteristic wavelength of the coating or substrate. 3.3.3 Energy dispersion
Use a frequency detector or energy analyzer to separate the radiation energy of the coating or substrate. X-ray energy is usually expressed in wavelength or equivalent energy. The relationship between them is AE = 1. 239 6
Where a is wavelength, nm:
energy is 1. keV.
3.4 Detection
The long dispersion system is usually detected by gas proportional counter and scintillation counter. The energy dispersion system is usually detected by proportional counter and multi-channel analyzer. 3.5 Thickness measurement
3.5.1 Thickness measurement method
There are two X-ray thickness measurement methods:
(2)
GB/T 16921—1997
a) Emission method This is a thickness measurement method that measures the characteristic radiation intensity of the covering layer. When the thickness of the covering layer is less than the saturation value, this intensity will increase with the increase of the thickness of the covering layer (see Figure 1). b) Absorption method This is a thickness measurement method that measures the characteristic radiation intensity of the substrate. The rays that pass through the covering layer are absorbed by the covering layer and attenuated. Therefore, when the thickness of the covering layer is less than the saturation thickness, its intensity decreases with the increase of the thickness of the covering layer (see Figure 1h). When using the absorption method for actual measurement, ensure that there is no intermediate covering layer. The absorption characteristic curve is similar to the emission characteristic curve. The emission method can also be combined with the absorption method to measure the thickness by the ratio of the characteristic radiation intensity of the cover layer and the matrix. This method basically eliminates the influence of the distance between the test sample and the detector. Thickness of the cover layer
=) X-ray emission method
h) X-ray absorption method
Figure 1 Relationship between count rate intensity and cover layer thickness 3.5.2 Relationship curve
In all methods, the fluorescence radiation intensity is obtained by measuring the cumulative pulse value within a certain predetermined time. The applicable instruments currently sold on the market all directly adopt the normalized count rate system. From formula (1), it can be seen that the normalized count rate of the substrate without a covering layer greater than the saturation thickness is 0, while the normalized count rate of the covering layer greater than the saturation thickness is 1. Therefore, the count rates of all measurable thicknesses are within the normalized count rate range of 0 to 1. The relationship between unit area mass and fluorescence counting rate is shown in Figure 2. The logarithmic range is -
, the hyperbolic range is
0, the counting rate of saturated materials without coverage is
1, and the counting rate of saturated materials with coverage is
Figure 2 Relationship between unit area mass and naturalized counting rate. As shown in Figure 2, when measuring, the products with naturalized counting rate in the range of 0.3-0.8 can achieve the best sensitivity and measurement accuracy in the entire thickness measurement range by using thickness standards. When measuring the thickness value of other areas: due to the change of thickness: the relative uncertainty of the same thickness standard block may increase. At this time, other applicable standards with lower measurement uncertainty should be used and added to establish the correct mathematical relationship to ensure the measurement accuracy. When measuring a combined system of cap/matrix materials with large radiation energy differences (energy dispersion systems), a calibration standard with a similar or identical matrix is not necessarily required if the characteristic count rate ratio of the saturated body without a cap is very high (typically 10:1) (because the matrix material does not radiate in the same energy band as the cap material). When measuring a combined system of cover/substrate materials with similar energies, when the characteristic count rate ratio of the saturated cover layer to the uncovered substrate is 1:3, it is often necessary to select a suitable "filter" that selectively absorbs a certain material (generally the radiation of the substrate + the radiation of another material) and allows most of it to pass smoothly, thereby improving the measurement accuracy. This filter is usually placed manually or automatically between the tested surface and the detector. 3.6 Multi-layer thickness measurement
When the characteristic X-ray radiation of the inner layer of the cover is not completely absorbed by the outer cover layer, both the inner and outer cover layers may be measured, which requires the installation of an energy dispersion device of a multi-channel analyzer to simultaneously receive the characteristic energy bands of multiple cover layers. 3. 7 Measurement of alloy layer thickness
The thickness of some alloy or compound coatings can also be measured by X-ray spectroscopy, but its composition must be known or identified or its composition can be measured before thickness measurement.
Reference Note 3: The identified composition will introduce thickness measurement errors. Some coatings will form alloys through mutual diffusion with the substrate: the existence of these alloy layers will increase the uncertainty of measurement.
4 Instruments
A standard X-ray thickness measuring device is generally composed of an energy dispersion device and a microprocessor. The microprocessor converts radiation intensity into mass or thickness per unit area, and can store standard data and perform various measurement statistical calculations. The main components of the thickness measuring device include a primary X-ray source, a collimator, a sample stage, a detector and an evaluation system (see Figure 3). Note 4: Special components should be introduced when necessary. Special software, electronic filtering or physical filters are used to separate, filter or absorb the characteristic fluorescence energy of one or more materials present. The introduction of these devices can enhance the fluorescence of the material being tested, thereby reducing the measurement uncertainty. X-ray tube
Test sample
Detector
X-ray tube
a) X-ray tube
4.1 Primary X-ray source
Collimator
Filter
Test sample
Detector
Radioactive isotope
Collimator
Test sample
c) Radioactive isotope Primary X-ray source
Figure 3 Illustration of the main components of the energy dispersion system Collimator
Detector
Filter
b) X Radiation back
GB/T 16921:-1997
Usually used X-ray tubes or appropriate radioactive isotopes excite the fluorescence radiation used for measurement. 4.2 Collimator
A collimator is a single or multiple holes with precise dimensions that allow X-rays to pass through. These holes can be of any shape in theory, but the size and shape of the holes will determine the size of the incident X-ray beam on the surface of the cover to be measured. Existing commercial instruments generally use round, square or rectangular hole collimators.
4.3 Detector
A device used to receive the fluorescence radiation of the sample to be measured and convert it into a measurable radio signal. It can select one or more surface cover layers, intermediate cover layers and the characteristic energy spectrum of the base material. 4.4 Evaluation system
The software program configured according to the instrument design processes the acquired data to determine the unit area mass or thickness of the cover layer of the sample to be tested. 5 Factors Affecting Measurement Results
5.1 Counting Statistics
5.1.1 Introduction
Since the generation of X-ray photons is completely random, the number of emitted photons in a fixed time interval is not the same, so statistical errors are generated. This statistical error always exists in all radiation measurements. The counting rate in a short time interval may be very different from the counting rate in a long time interval, especially when the counting rate is low. To reduce the counting statistical error to an acceptable level, a properly long counting period must be used to accumulate enough counts. Statistical errors are independent of other errors.
5.1.2 Standard Deviation of Counts
The standard deviation S of the random counting error is very close to the square root of the total counts N, that is: S&N
Where: N is the counts at a given time.
In all measurements, the correct count rate within the range of N(1±
5.1.3 Standard deviation of thickness
> was 95%. YN
.-.(3)
The standard deviation of thickness measurement is different from the standard deviation of counting, but has a "definite function relationship" and depends on the slope of the calibration curve at the measurement point. The standard deviation of most commercially available X-ray fluorescence thickness gauges is expressed in thickness units or as a percentage of the average thickness. 5.2 Calibration standard block
When measuring thickness, it is necessary to calibrate with a thickness calibration standard block. The uncertainty of the standard block should generally be less than 5%. However, it is very difficult to ensure an uncertainty of 5% for thin coatings or due to roughness, porosity and diffusion. The calibration standard block can only be used when the normalized count rate of the coating is within the thickness measurement range of 0.05 to 0.9. 5.3 Coating thickness||t t||The range of the coating thickness affects the measurement uncertainty. In the curve of Figure 2, the measurement accuracy is the highest in the 0.3-0.8 logarithmic region. In other regions, the measurement accuracy will be significantly reduced. ...-Generally speaking, the thickness limit range is different for different coating materials. 5.4 Measurement area
The measurement area is determined by the size of the collimator aperture. In order to obtain satisfactory statistical counts in a short counting cycle (see 5.1), a collimator aperture that is commensurate with the shape and size of the sample should be selected to obtain the largest possible measurement area. The area of the collimator aperture should generally not be larger than the area available for measurement on the coating surface. However, in special cases, the measured area can be smaller than the beam area (see 5.11). However, it must be noted that the measurement base area should not be unable to obtain correct measurement results due to the saturation count rate. Calibration must be performed on samples of the same size. 5.5 Coating composition
GB/T 16921-1997bzxz.net
Extraneous impurities in the cap layer, co-precipitates or metal layers formed by diffusion at the interface between the matrix and the overburden will affect the measurement of the mass per unit area. The thickness measurement will also be affected by voids and pores. Calibration standard blocks prepared under the same conditions as the overburden and generated by representative characteristic X-rays can be used to eliminate these errors. Since the presence of included pores or voids leads to different densities, the cap layer with these defects is best measured by the mass per unit area. If the density of the cap layer to be measured is known, it can be input into the measuring instrument for correction (see 5.6). ||tt ||5.6 Density of the covering layer
If the density of the sample material of the magic covering layer is different from that of the calibration standard, a corresponding error will be generated during the thickness measurement. When the density of the covering material is known, this error can be eliminated and the thickness value can be obtained (see 3.1). If the measurement is in units of mass per unit area, the linear thickness can be obtained by dividing the measured value PA by the density of the covering layer P
d-×10
If the measurement is in linear units, the density-corrected thickness formula is: d=de
Where d is the linear thickness um
d. Linear thickness reading.um,
p,m-density of the covering material of the thickness calibration standard block, g/cm\; density of the covering material of the test specimen, g/cm, PA-mass per unit area of the covering layer of the test specimen, mg/em5.7 Matrix composition
When measuring thickness by X-ray emission method, the influence of matrix composition on the measurement result can be ignored under the following circumstances:4)
a) The wavelength of fluorescent X-ray emitted by the matrix does not invade the characteristic energy band of the fluorescence radiation of the selected covering layer. If it invades, measures must be taken to eliminate its influence
b) The fluorescent X-rays of the matrix material cannot excite the covering materialc) Use the intensity ratio method (see 3.5)
When measuring the thickness by X-ray absorption method, the matrix composition of the calibration standard block and the reference standard block should be the same as the matrix composition of the specimen.
5.8 Substrate thickness
When measuring thickness by X-ray emission method, the substrate of the double-sided coating sample should be thick enough to prevent the reverse coating from generating interference.
When measuring thickness by X-ray absorption method, the substrate thickness should be equal to or greater than its saturation thickness, otherwise the instrument must be calibrated with a reference standard block of the same substrate thickness (see 6.3). 5.9 Surface clarity
The attached substances on the surface of the measured coating, such as dust, grease or corrosion products, as well as protective layers and surface treatment layers, will cause measurement errors. 5.10 Intermediate coating
When the absorption characteristics of the intermediate coating are unclear, the absorption method cannot be used, and the emission method is recommended. 5.11 Sample yield
When measuring the thickness of the curved surface coating, a collimator hole of appropriate shape and size should be selected to minimize the influence of the surface curvature. For example, in practice, the use of a rectangular hole collimator to measure the surface of a cylinder is better. Generally, as long as the measurement allows, a collimator with a smaller aperture should be selected to reduce the influence of the curvature of the plane.
If a standard block of the same size or shape as the sample is used for calibration, the influence of the curvature of the sample will be eliminated, but this measurement must be performed on the same position, surface and measurement area of the sample. In this case, it is possible to use a collimator aperture with a larger area than the test sample. 5.12 Excitation energy and excitation intensity
GB/T 16921-1997
Since the intensity of fluorescence radiation depends on the excitation energy and excitation intensity, the instrument used must be able to stably provide X-rays with the same excitation energy and excitation intensity during calibration and measurement. 5.13 Detector
Instability or abnormal operation of the detector system will also introduce measurement errors. Therefore, before use, the instrument must be subjected to a stability test by means of an automatic or manual method. During the test, a single reference piece or sample is placed on a sample table irradiated with X-rays and is not moved during the entire test process. A series of single count rate measurements are made over a short period of time, selected according to the test requirements. The standard deviation of the series should not be significantly greater than the square root of the mean value of the series. In order to confirm the stability over a longer period of time, the above results can be compared with the results obtained previously at the same time. The time used for a single measurement series or the required interval between two independent measurement series is used to determine the stability of that period. 5.14 Radiation range Since the loss of radiation in the path will increase the measurement error, the radiation range should be as short as possible. When measuring elements with an atomic number less than 20, since sufficient radiation intensity cannot be excited under air conditions to meet the requirements of the type of instrument shown in Figure 3, it is necessary to perform the spectrometry under vacuum or ammonia conditions.
5.15 Conversion of count rate to mass per unit area or thickness In addition to direct manual calculation, commercial instruments generally use microprocessors to convert count rates to mass per unit area or thickness. The microprocessor usually has only one program derived by mathematical methods, which can meet the actual requirements of the test after inputting the data of appropriate calibration or reference standard blocks. The reliability of the conversion depends on the correctness of the standard line, equations, calculation methods and other conversion methods, and also on the quality, quantity and thickness calibration of the calibration standard blocks at the corresponding points when measuring thickness. When a micro-cover layer causes additional fluorescence in other layers, the conversion method should take this into account. Extrapolation within the thickness range determined by the calibration standard block may lead to large errors. 5.16 Inclination of the sample cut surface
When measuring, if the inclination of the surface to be measured relative to the incident X-ray beam is different from that when the calibration standard block is used, the count rate will change significantly, causing measurement errors. For example, a difference of 10 in inclination can result in a change of 4% in the count rate. 6 Calibration of the instrument
6.1 Overview
6.1.1 General requirements
The instrument calibration should be carried out in accordance with the instrument manual, and appropriate consideration should be given to the factors described in Chapter 5 and the requirements in Chapter 8. The instrument should be calibrated at least once a day using a thickness standard that is consistent with the cap/substrate to be measured. If the measured thickness value is obviously not in accordance with the requirements in Chapter 8, the instrument should be recalibrated. 6.2 Calibration Method
6.2.1 Linear Range Calibration
For measuring thin overburdens, since they are generally within the linear range with a normalized count rate below 0.3, it is recommended to use an uncovered substrate and a single overburden thickness standard of known thickness within the linear range to obtain a retrograde calibration: 6.2. 2 Logarithmic range calibration
When calibrating the thickness measurement in this range, at least four standard blocks must be used in the passband: a standard block of bulk material with an undegraded thickness: a standard block of double-cover material with at least the saturation thickness, a standard block of cover with a thickness close to or at the lower limit of the logarithmic range, and a standard block of decapping with a thickness close to the upper limit of the logarithmic range. 6.2.3 Full measurement range calibration
For full range measurement from 0 to the hyperbolic range thickness, it is also necessary to add a cover standard block with a thickness close to the end value of the limited range for calibration.
When measuring thin cover layers with a fully calibrated instrument, interpolation can be performed between the zero value and the minimum thickness value of the standard block. However, when measuring thick cover layers, if the maximum thickness value of the standard block is exceeded, it is generally not necessary to extrapolate, otherwise unreliable results may result (see 5.2). 6.3 Standard Blocks
6.3.1 General Requirements
GH/R16921—1997
The standard blocks used to calibrate the instrument must be reliable. The uncertainty of the thickness measurement depends directly on the uncertainty and measurement accuracy of the standard blocks. The standard blocks should have a uniform desired cover with a known unit mass or thickness. The thickness of the effective cover should not exceed ±5% of the specified value. The results are reliable only when they are used for cover layers of the same composition or known density. When measuring a cover layer of metal composition, the composition of the calibration block does not need to be the same, but it should be known. 6.3.2 Box Standard Sheets
If a metal foil is used as a standard sheet on a suitable substrate, it must be noted that the contact surface is clean and free of wrinkles and kinks. If there is a density difference, it must be compensated before measurement unless the measuring plate allows it. 6.4 Selection of Standard Blocks
The instrument can be calibrated by the unit mass or thickness value of the standard block, but the effect of density must be taken into account. Although the instrument design allows for some deviations from the ideal (see 3.1), the standard block must have the same or very similar coating and matrix materials as the test specimen. 6.5 X-ray emission (or absorption) characteristics of the standard The cover layer of the thickness standard block should have the same emission (or absorption) characteristics as the cover layer of the test specimen. If the thickness is measured by the X-ray absorption method and the intensity ratio method, the matrix of the thickness standard block should also have the same emission (or absorption) characteristics as the matrix of the test specimen. 6.6 Matrix thickness
When the matrix thickness is less than its saturation thickness, the X-ray absorption method is generally used. In this case, the matrix thickness of the specimen and the calibration standard block should be the same.
7 Measurement Procedures
7.1 General Requirements
Operate the instrument for measurement according to the instrument manual, and take due account of the factors listed in Chapter 5 and the accuracy requirements of Chapter 6.3 and Chapter 8. 7. 2 Precautions
2.1 Selection of collimator or aperture
Select the collimator or aperture according to the shape of the specimen and the effective test area. The distance between the collimator aperture and the specimen should remain unchanged during the test.
7.2.2 Curved Surface Measurement
When measuring a curved surface, if a sufficiently small collimator aperture can be selected so that the surface being tested is approximately consistent with a flat surface, the measurement can be performed after correction with a flat thickness standard block. Otherwise, the requirements of 5.4 and 5.11 should be considered. 7.2.3 Calibration
To ensure that the instrument and measurement conditions remain unchanged, the instrument should be calibrated at specified time intervals according to the requirements of the instrument manual. 7.2.4 Measuring time
Since the measurement uncertainty depends on the measurement time, a measurement time with an acceptably low measurement uncertainty should be selected. 7.2.5 Number of measurements
The measurement uncertainty is related to the number of measurements. An increase in the number of measurements will reduce the measurement uncertainty. If the number of measurements increases by times, the measurement uncertainty will decrease by one
The standard deviation should be calculated from at least 10 measurements on the same measurement surface. 7.2.6 Protective measures
Problems related to the protection of operators against X-rays shall be handled in accordance with the current relevant national standards and regulations. 7.2.7 Result expression
The conversion of intensity value (count rate) to mass per unit area or thickness can be performed automatically by commercially available instruments. For other instruments, a calibration curve similar to Figure 1 can be drawn. Generally, the results of mass per unit area are expressed in mg/cm2, and the results of thickness measurement are expressed in m. 8 Measurement uncertainty
GB/T 169211997
The calibration and operation of the instrument should make the measurement uncertainty less than 10%. In order to reduce the measurement uncertainty, the measurement time can be increased, the number of measurements can be increased, and the collimator aperture size can be changed (until the detector reaches saturation). 9 Test report The test report should include the following content: a) This standard number or reference standard number; b) Test interval; c) The measuring instrument used; d) The mark or abbreviation of the sample; e) Measured part of the sample:
[) Average number of measurements:
8) Diameter of the measuring instrument used for measurement and the area of measurement (if the two are different, they must be indicated separately): h) Measured value,
i) Density gauge used for thickness gauge and reason for use "Standard deviation of measured value";
k) Differences from the method of this standard
1) Matters that may affect the interpretation of the reported results; m) Name of laboratory and operator:
Wei Yi Layer
Palladium-nickel composite
Steel-lead
GB/T 169211997
Appendix A
(Standard Appendix)
Typical measurement ranges for common coating materials
Copper or nickel
Copper or nickel
Copper or tin
Copper or nickel
Copper or tin
1The measurement uncertainty is not constant over the entire range and increases towards each end of the range. 3The given values are approximate and depend on the acceptable measurement uncertainty approximate thickness range, r2
0~-100. 0
0~~ 40. 0
3 If the surface layer and the middle layer are measured at the same time, the measurable thickness range of each cover material will change due to the various interactions of the fluorescent X-ray beam, that is, the surface layer will absorb the fluorescence of the middle layer. For example, when measuring gold and nickel on copper, if the thickness of the gold coating exceeds 2.0um, there is not enough light to ensure high-precision measurement of the coating.
1 When measuring the thickness of a coating greater than 0 um (such as gold on copper or nickel, 005 um), the measuring instrument should display the measurement uncertainty specified by the instrument. This requires understanding the lower limit of the measurement range.
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