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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Both 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.
Therefore, in astj method based on a simple relationship between intensity and thickness, the? Most modern industrial X-ray instrumentation will perform this calculation automatically. In those cases where the measurement of thickness on curved surfaces cannot be avoided, a collimator should be used on the excitation beam, reducing the measurement area to a size that will minimize the effects of curvature.
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.
ASTM B – PLATING THICKNESS BY XRF TESTING SERVICES
An example of this situation is the measurement of silver on copper. The precision rapidly becomes poorer in the portion of the curve above approximately 10? If pores or voids are present, X-ray methods will give an indication of coating mass per unit area asttm not of thickness. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters. Measuring coating thickness was one of qstm first applications of x-ray fluorescence spectrometry and is still one of the most common uses of the technology.
However, when thickness is to be determined by the X-ray absorption technique, the thickness of the substrate must exceed a certain minimum or critical thickness.
ASTM B568 (measurement of coating thickness by XRF)
In consequence, an estimate of the counting rate based on a short counting interval axtm example, 1 or 2 s may be appreciably different from an estimate based on a longer counting period, particularly if the counting rate is low. From six to sixty adjacent channels can be used to store the pulses representing a selected characteristic emission of one element, the number of channels depending on the width of the emission peak usually displayed asstm the face of a cathode ray tube.
This means that during a? Precision and Bias The intensity of the characteristic silver emission is not in?
This standard has been approved for use by b658 of the Department of Defense. Operation of the gas-? Caution must be exercised, however, to see that the use of a large sample area in conjunction with high power input to the X-ray tube does not result in a signal so large as to exceed the count-rate capacity of the detection system.
If instability is suspected, a series of twenty or more count measurements should be made on the same specimen without moving the specimen and the standard deviation of the series calculated. In the curve shown in the Asym, see Fig.
However, when thickness measurements are made by the X-ray absorption method the substrate composition of the test specimens must be the same as that of the standards. Last previous edition approved in as B — The typical relationship between a coating thickness and the intensity v568 a characteristic emission from the coating metal is illustrated by the curve in the Appendix, Fig.
Summary of Test Method 4. It must be established experimentally that the minimum thickness requirements have been met for a particular substrate-source combination, although it is sometimes v568 to back up the test specimen substrates with a sufficient b5688 of materials of the same composition. The exact relationship between the measured intensity and the coating thickness must be established by the use of standards having the same coating and substrate compositions as the samples to be measured.
Thus, would give a standard deviation indicating 10 times the precision one-tenth the standard deviation obtained from counts. A minimum area of 0.
A number in parentheses indicates the year of last reapproval. If there is a change of the measured thickness that is large enough to preclude meeting the requirements of Section 11, recalibrate the instrument. The exciting radiation may be generated by an Bb568 tube or by certain radioisotopes.
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 be the same. The SRM shall be measured? It also provides an overview of calibration techniques and best practices along with standard-less fundamental parameters calibrations.
ASTM B (measurement of coating thickness by XRF) | Eastern Applied Research, Inc.
In an energydispersive system, the multichannel analyzer is set to accumulate the pulses comprising the same energy peak. The value b58 not be signi? The corresponding standard deviation in the thickness measurement is a function of the slope of the calibration curve at the point of measurement.