ASTM B – Designation: B – 98 (Reapproved ) UNCONTROLLED (if printed out) Standar. Basic Description: ASTM B X-Ray Fluorescence (XRF) is a non-destructive method of measuring plating thickness by using an X-ray beam to excite the. Designation: B − 98 (Reapproved ) Standard Test Method for This test method is under the jurisdiction of ASTM Committee B08 on Metallic.
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In an energydispersive system, the multichannel analyzer is set to accumulate the pulses comprising the same energy peak. It must be established experimentally that the minimum thickness requirements have been met for a particular substrate-source combination, although it is sometimes possible to back up the test specimen substrates with a sufficient thickness of b5568 of the same composition.
This procedure is commonly used for the measurement of hard gold coatings having a density of The exact relationship between the measured intensity and the coating 5b68 must be established by asfm use of standards having the same coating and substrate compositions as the samples to be measured.
This method is frequently used to measure gold thickness, platinum thickness, nickel thickness, or zinc thickness over metallic substrates. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every?
Calibration standards having the same radius of curvature as that of the test specimens can also be used to eliminate curvature effects.
Due to the low intensity of radioisotopes, they are unsuitable for measurements on small areas less than 0. Material testing you can trust since Protective coatings such as lacquer or chromate conversion coatings over the coating to be measured will also affect the results.
The instrument calibration may be made with standards of silver on nickel. Operation of the gas-? Our laboratory also provides laboratory services for plastic testingmetal testingrubber testingoil testingpaint testingplating testingadhesive testingcircuit board testingand other testing. However, if the method is based on intensity ratios rather than absolute intensities, minor variations in excitation energy are compensated for.
If the characteristic emission energies of the coating and substrate are sufficiently different, the only contribution of the substrate will be due to background.
ASTM B568 (measurement of coating thickness by XRF)
These limiting thicknesses are, in general, different for each coating material. Depending upon the atomic number of the coating, when the coating thickness is increased to a certain value, the characteristic radiation from the substrate will disappear, although a 2 Copyright by ASTM Int’l all rights reserved ; Reproduction authorized per License Agreement with Victoria Boyer ; Wed Mar 23 In all, thirteen 13 factors are highlighted and worth knowing about in case ast, occur.
The benefit to operators is that it details the variations in x-ray spectrometry systems and explains how XRF works with some terminology that may be useful. This does not mean that the result would necessarily qstm ten times as accurate see 7. For information on this important aspect, reference should be made to current documents of the National Committee on Radiation Protection and Measurement, Federal Register, Nuclear Regulatory Commission, National Institute of Standards and Technology formerly the National Bureau of Standardsand to state and local codes if such exist.
Published data in tabular form are available that relate spectrogoniometer settings to the characteristic emissions of elements for each of the commonly used analyzing crystals. The chief advantage of X-ray tube excitation is the high intensity provided.
The typical relationship between a coating thickness and the intensity of a characteristic emission from the coating metal is illustrated by the curve in the Appendix, Fig. If the coating on the standard is gold, but b5688 electroplated under conditions known to be the same as the coating being measured, the X-ray properties may be assumed to be the same for mass per unit area measurements. It is recommended that two sets of standards be maintained, that is, a set of primary standards and a set of working standards.
Care must be taken that the coating and substrate are thick 5b68 to prevent the primary X-ray beam from reaching and? In general, the radiation intensity varies directly with the current and the square of the potential. Standards representing various thickness ranges of a number of coatings on different substrates are generally available from thickness gage manufacturers. The major disadvantage of radioisotope excitation is the much lower intensities available as compared with X-ray tube sources.
ASTM B – 98 Standard Test Method for Measurement of Coating Thickness by X-Ray Spectrometry
If the coating of the standards is electrodeposited from the same bath and under the same conditions as the coating to be measured, the X-ray properties may be assumed to b658 the same. If not, make sure that the calibration has been made with a substrate having the same thickness and emission properties as the test specimens. A minimum area of 0.
This type of detector is maintained at a very low temperature in a liquid-nitrogen cryostat 77K. Thus, would give a standard deviation indicating 10 times the precision one-tenth the standard deviation obtained from counts. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
This shall be veri? Under such circumstances, thickness measurements must be corrected for density differences, unless density differences can be shown to be insigni?
The intensity of the characteristic silver emission is not in? Asttm of the techniques described below are based on the use of primary standards of known coating thicknesses which serve to correlate quantitatively the radiation intensity and thickness.
These should be used only to calibrate and periodically check the condition of the working standards. This error is independent of other sources of error such as those arising from mistakes on the part of the operator or from the use of inaccurate standards. This standard has been approved for use by agencies of the Department of Defense. Precision and Bias In the curve shown in the Appendix, see Fig.